2007-05-28

Carbon Nanotube (CNT) Links and Resources


http://www.cheaptubesinc.com
If you have keen interest in the Carbon Nanotube(CNT) field, you can go to that website.

http://www.nanotechnology.com

Small Times: Big News in Small Tech
Chemical Engineering & News

Nanotechweb.org

Nanotechnology Now

Nanobusiness Alliance

NSTI Nano Science and Technology Institute

The Foresight Institute

Nano-vip.com
www.nano-tsunami.com

http://www.sonics.biz/

http://www.understandingnano.com/



Technology News and Resources

Dispersion of CNTs - Cheap Tubes is now a sales representative company for a complete line of Ultrasonic Equipment. Please click here to find out more about the Sonics VCX 750 and other equipment. To view our recommended dispersion process, please visit our FAQs page or click here.



Cheap Tubes Recommends the following authors.

Nanotechnology: Basic Science and Emerging Technologies, M. Wilson et al, Chapman and Hall (2002) ISBN 1-58488-339-1

Carbon Nanotubes and Related Structures : New Materials for the Twenty-first Century”, P. F. Harris, Cambridge University Press (1999) ISBN 0-521-55446-2

Physical Properties of Carbon Nanotubes, R. Saito et al, Imperial College Press (1998) ISBN 1-86094-093-5

Wondrous World of Carbon Nanotubes (Internet Reference), M. J. M. Daenen et al. www.students.chem.tue.nl/ifp03/

The Science of Fullerenes and Carbon Nanotubes : Their Properties and Applications”, M. S. Dresselhaus et al, Academic Press (1996) ISBN 0-12221-820-5

Carbon Nanotubes – Preparation and Properties, T. W. Ebbesen ed., CRC Press (1996) ISBN 0- 84939-602-6

Carbon Nanotubes: Synthesis, Structure, Properties, and Applications, M. S. Dresselhaus et al eds., Springer-Verlag (2000) ISBN 3-54041-086-4

Carbon Nanotubes, T. W. Ebbesen, Ann. Rev. Mater. Sci. 24, 235 (1994); Physics Today 381, 678 (1996)

B.Q. Wei, et al, Appl. Phys. Lett. 79 1172 (2001)

R.H. Baughman, Science 290, 1310 (2000)

D.Walters, et al., Chem. Phys. Lett. 338, 14 (2001)

B. Gao, Chem. Phys. Lett. 327, 69 (2000)

R.Z. Ma, et al., Science in China Series E-Technological Sciences 43 178 (2000)

Nanotech Fortunes: Darrell Brookstein



Popular Technology Websites

CBS News Technology

CNN Sci-Tech

CNet Tech News

MIT Technology Review

Nature.com

USA Today-Tech

Science News

Science Daily Magazine

Scientific American

Technology Research News

The New York Times- Technology

The Smalley Group at Rice

The Nobel Prize in Chemistry 1996

http://library.lanl.gov/infores/nanotechnology.htm

http://www.mtpc.org/mni/research.htm

http://scitation.aip.org/dbt/dbt.jsp?KEY=VIRT01



Industry Links
IBM Nanoscale Science Department: Home Page

Academic and Government Resources
Australian National University in Canberra: Nanotubes produced by ball milling

CARAMEL Consortium, Sweden: Development of Nanotube-Based Nano-Electromechanical Devices (NEMS)

Clemson University: Apparao Rao's Nanotube Research site

Duke University: Jie Liu's Group: CVD Synthesis of Single-Wall Nanotubes

Enzo Menna at CNR Padova: Nanotubes and Nanotechnology links

ICB-CSIC Zaragoza (Spain): Group of Carbon Nanostructures and Nanotechnology

Michigan State University: David Tomanek's Nanotube Page

NASA JSC Nanotube Site

North Carolina Nanoscale Material Center

NASA: Use of Carbon Nanotubes in Space

Roberto "Maranza" Marangoni's Nanotube Page (in Italian)

Oxford University: Jeremy Sloan's page on 1D crystals in Nanotubes and related topics

Oklahoma University: Large Scale Production of Single Walled Nanotubes (Daniel Resasco)

Penn State University: Vincent Crespi's Nanotube page (general audience)

Rice University: Center for Nanoscale Science and Technology

University of Texas: Malcolm Brown's Nanopage

University of California at Berkeley: Alex Zettl's Group Home Page

University of Sussex: Harry Kroto's Fullerene Group Home Page

University Fribourg (Switzerland): Synthesis and Characterization of Carbon Nanostructures and Nanotubes

University of Kentucky: Advanced Carbon Materials Science Research and Engineering Ctr.

University of Toulouse: Nanocomposites and Carbon Nanotubes Group

University of Tokyo: Shigeo Maruyama's Nanotube Site

University of Helsinki: Ion irradiation of carbon nanotubes

University of Oxford: Malcolm Green's Nanotube Group

Universite Paris-Sud in Orsay: Fullerenes and Nanotubes (including nanotubes in zeolite and nanotube-based fibers)

Weizmann Institute: Daniel Wagner's Page on Mechanical Properties of Carbon Nanotubes and Composites

NIST - Nanotechnology Program

DOD - Nanoscience and Technology

Nanoscale Science, Engineering and Technology

The National Nanotechnology Initiative (NNI)

NASA's Nanotechnology Team

http://www.nystar.state.ny.us/rsch/nanotech.htm

Diccionario de Nanotecnología- Nanotubos (in Spanish)

Yongsheng Chen's group at Nankai University- Nanotube research at the Nanomaterials and Molecular Devices Laboratory

Federal University of Rio Grande do Sul- Ceramic Materials Laboratory

Emmanuel Flahaut's Double-walled Carbon Nanotube Page

Nanotube-based Space Elevator project

"Carbon nanotubes roll on"

"Multiwall carbon nanotubes"

"Single-wall carbon nanotubes"

"Controlling nanotube growth"

"Industry sizes up nanotubes"

PSIgate

CSIRO media release of 16 June 1999- Nanotubes for better TV screens

Boston College- Zhifeng Ren's Group

ETH Zürich- Home page of the Nesper group

Peter Butzloff- Nanotube Poetry

TechExpo- The Online Expositions for High Technology

University of Namur (Ph. Lambin)- Connecting carbon nanotubes

Purdue University- Nanotube Research in Ron Reifenberger's Lab

University of Mainz- Carbon Nanostructures page of Florian Banhart

Berkeley Lab- Electronic Devices within Carbon Nanotubes

University of Warwick- Links to Fullerene Sites

Michigan State University- Daily InScight Report

Molecular Dynamics Simulation of a Nanotube-Based Memory Element

University of Michigan- SWNT Production in a Reduced Gravity Environment

http://www.research.ibm.com/nanoscience/

Cambridge University- Milo Shaffer's Home Page

Michigan State University- Cluster Science Collaboration

North East Wales Institute of Higher Education- Advanced Materials Research Laboratory

Thomas Laude- Nanostructures of carbon and boron nitride

Rice University- Ching-Hwa Kiang's Group Home Page

Penn State University- Milton Cole's Page on Adsorption in Nanotubes

University of Sussex- Harry Kroto's Fullerene Group Home Page

North Carolina Center for Nanoscale Materials

Penn State University- Peter Eklund's Group Home Page

University of Pennsylvania- Jack Fischer's Group Home Page

NASA Carbon Nanotube Gallery

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ZPT-98型坦克研制历史及现状

ZPT-98型坦克研制历史及现状

一:研发史

1970年底,我国第二代主力坦克122中型坦克在经历3年多的发展后,因无法突破技术瓶颈的制约宣告失败。直至文革结束前的数年间,我国主力坦克的发展步伐处于停滞不前的状态。与此同时,西方国家的装甲部队正对其第二代主力坦克进行不断改进,并在苏联t-64和t-72坦克的刺激下,纷纷加快了第三代主力坦克的研发步伐。此时,受多种因素的制约,我国的坦克工业还仅徘徊在修修补补上,逐步拉大了与世界水平的差距。 挂装附加装甲的99坦克
1977年2月,在抖落了文革重负后,看着手中已经落后于北约和苏军近15年的装甲力量,陆军首次向军委科技装备委员会呈报了新型主力坦克的战术、技术指标要求。在上级的要求下,军工部门随即展开了新型坦克的研发工作。1978年4月,国防科工委和五机部在山西大同召开了“784”会议,讨论第二代(以后改称第三代)主力坦克的研发方案,重新提出了新型第二代主力坦克的研发目标,并对战技指标进行了论证。会议决定,第二代坦克以德国的“豹”2坦克为起点,主要作战目标是苏军的t-72坦克。会后,五机部成立了会战指挥部,任命了总设计师和副总设计师,掀开了我国坦克工业自文革后的首次发展高潮。

经过协作攻关后,1979年3月,617厂和201所研发成功了代号1224的新型坦克论证性底盘试验样车。该车安装有120毫米火炮,液力机械式变速箱、摩擦减震器和mb8v331tc41型引擎,总装成功后立即投入试车,主要目的是为了考核从德国引进的mb8v331tc41型引擎、辅助系统以及行走装置、总体布局和整车的总体性能。随后,617厂和201所又研发了代号1226和1226f2的两辆试验样车。这两辆试验样车的外形相同,除安装了与1224试验样车相同的120毫米滑膛炮外,无论是在坦克外形还是在车体结构上都与1224试验样车有很大不同,其战斗全重分别为45.3吨和45.8吨,车全长为9.947米(炮向前)。两辆样车的区别是动力装置系统不同,1226试验样车安装的是636厂生产的8v165型柴油引擎,该引擎的功率为1000马力;1226f2试验样车安装的是616厂生产的12v150型引擎,其功率也为1000马力。两种试验样车的动力传动装置均为纵置式,可整体吊装,给保养车辆带来了很大便利。另外,两种样车均采用了由617厂研发的液力机械综合变速箱,该变速箱有4个前进檔和1个倒文件,操作轻便,加速性和转向性能较好。悬吊装置采用了扭杆弹簧和液气筒复合悬吊,具有很好的避震性能。由于行走系统采用了6对小路轮和挂胶履带,与以往的坦克相比,两辆试验样车的通行能力和行走系统的寿命有明显提高。


从70年代末至80年代初,如何在平坦的三北地区防御和阻击北方随时会兵临城下的重装集群,对于装备窘陋的陆军而言是个大伤脑筋的问题。借着与北约国家刚建立的准盟友关系,我国曾考虑引进德国的“豹”2坦克作为陆军装甲部队的主力装备。一时间,军方高层和工厂的技术人员成了德国克劳斯-玛菲公司的常客。单在综合了全面的考量后,军方最终还是决定在吸收消化“豹”2技术的基础上研发具有我国特色的主力坦克。因此,在设计1224、1226和1226f2试验样车的过程中,充分借鉴了德国“豹”2坦克的许多设计理念。


1226和1226f2试验样车采用了焊接式炮塔,弹舱设置在炮塔尾部,乘员4人,在采用了许多新技术的条件下,试验样车取得了前所未有的一次性研发成功,同阶段的部件研发工作也呈现百花齐放的局面,使我国的坦克技术发展和技术储备有了新的实践和积累。

1981年80式坦克被指定为我国第二代主力坦克,1224、1226和1226f2试验样车实际上便成了第三代坦克的前期预研车。80式坦克成为第二代坦克后,我国军工部门把第三代坦克的论证工作提到了首要议程。不久,由于在论证中出现了两种不同的设计理念而产生了严重的意见分歧;第一种设计理念主张在苏军t-72坦克的基础上研发第三代坦克,其依据是我国已完全掌握了t-72的技术性能,在此基础上研发新一代坦克对承袭了苏式风格数十年的坦克工业体系无需做大的的调整。该方案为3人制坦克,125毫米火炮,采用自动装填机。第二种设计理念主张另起炉灶,以研发新型坦克为契机,彻底摆脱苏式体系。其设计方案为:采用类似以色列“驰车”式坦克的设计风格,引擎前置,120毫米主炮,半自动装填机,动力系统为大功率柴油引擎或燃气轮机,打破以往传统的坦克设计理念。由于两种设计理念各不相让,分歧较为严重,导致第三代坦克项目论证工作暂时中断。

1984年7月,在统一了设计理念后,重新召开了由军方和研发部门(201所)共同参加的第三代坦克战术、技术指标补充论证会议,会议决定采用类似t-72坦克的整体设计方案,并任命祝榆生为总设计师。1986年夏,该项目由总参谋部与国防科工委联合上报国务院、中央军委;同年,国务院、中央军委正式批复“第三代坦克是装甲兵2000年的主要装备”。在国家“七?五”计划中,第三代坦克被列为武器研发的重点项目。“八?五”项目期间被列为军队四大重点装备项目之一。


1989年春,总参装甲兵部与我国北方工业公司签订了第三代主力坦克(第一阶段)合同书、来年初,617厂生产出了首辆第三代坦克试验样车,并进行了工厂定型试验。1991年,经充分论证后,三代坦克论证与分析组对三代坦克的战技指标由40余项增加到70余项,这对提高和完善三代坦克的作战性能产生了深远影响。1992年,617厂又生产了4辆三代坦克样车。1993年,相关部门就三代坦克炮塔正面防护系统三步指针项目召开了技术会,会上决定,为适应未来战争的需要,将三代坦克炮塔的正面防护从二步指标(600毫米)提高至三步指标(700毫米)。


1994年,总参兵种部和兵器总公司先后召开了两次“三代坦克火控系统研发方案评审会”。同年8月,在我国南方某地,2辆三代坦克初期样车进行了湿热地区的适应性摸底试验。试验中,2台样车共行驶了3800公里,发射各种炮弹200余发,完成16项试验项目。9月,在北京坨里和槐树岭地区又对三代坦克进行了可*性摸底试验和潜渡试验。1995年~1996年,3辆三代坦克初期样车在黑龙江塔河县北方试验场进行了寒区摸底试验。1996年初,兵种部三代坦克型号办公室在包头召开设计定型协调会。5月,617厂开始了三代坦克正式样车的总装工作。12月3日,在装甲兵装备技术研究所试验场隆重举行了三代坦克的交接仪式,三代坦克从此正式由工程研发阶段进入设计定型阶段。


12月底,试验部队迅速将三代坦克正式样车中的4辆调往塔河进行寒区适应性试验。在近2个多月的试验中,4辆样车累计行驶6900公里,完成近20余项试验项目。1997年底,三代坦克的正式样车再次进入塔河试验场进行寒区试验,4辆样车累计行驶20000公里,完成近30余项试验项目,发射各种炮弹760余发。到1998年底,在经历了5年的试验和部队试用后,三代坦克终于完成设计定型任务。经检测,三代坦克在火力、火控、装甲防护性能以及一些高新科技的应用上达到或超过了设计要求。由于三代坦克已被指定为“9910工程”(国庆五十周年阅兵)的重点车型,时间任务紧迫,在有关单位的不懈努力下,1998年底,三代坦克通过了鉴定定型,正式命名为ztz-98式主力坦克,并小批量生产参加“9910工程”。1999年10月1日,98式坦克在国庆阅兵式上首次公开露面。


在近10余年的研发过程中,三代坦克共耗资数亿人民币。参加阅兵式的单车造价为1600万人民币(约合190万美元),创下了我国国产坦克造价的新高。


在完成了98式坦克的设计定型后,科研单位又开始在该坦克基础上加紧研发改进型号。与98式坦克相比,98改的综合性能上又有较大提高,尤其是整车的可*性。2001年底,首批40辆98改坦克开始试装备解放军装甲部队。

二:整体布局

由于98式坦克的设计借鉴了t-72坦克的许多设计理念,所以从整体看,98式坦克就象t-72的放大版。98式坦克的底盘较t-72长出近1米,其路轮分布也较后者稀疏。与以往我国陆军的坦克相比,98式坦克的最大的变化体现在其炮塔方面,一改传统的卵形铸造炮塔,全面采用焊接结构,其正面与m1系列坦克有许多相似之处。

从整体布局上看,98式坦克仍采用传统布局模式,驾驶室前置,战斗室居中,动力室后置。车体采用装甲钢板焊接结构,由首部、侧部、尾部、底部以及风扇隔板、动力舱隔板合动力舱顶盖组成,车首上装甲板焊接有一对带弹性卡锁的牵引钩、两个前灯防护支架。车体翼子板上固定有外燃油箱、燃油供给管路、备品、工具附件箱以及外机油箱,车体尾部支架上固定有两个备用油桶。


坦克驾驶员位于车体前部中央,驾驶室上配有一扇单片舱门,舱门前的镜室内装有1具昼用单倍潜望镜和2具潜望镜。此外,驾驶员还配有1具双目微光夜视潜望镜,夜间视距为200米。


在车体首上装甲板内侧,布置有驾驶员舱门螺杆关闭装置和92式辐射与化学探测器以及滤毒通风装置。驾驶舱右侧布置有右燃油箱和弹架油箱,左侧有左燃油箱,驾驶员检测仪表板、蓄电池组以及电气设备,后面是自动装填机的旋转输弹机。


驾驶员室设有驾驶员座椅,座椅前面底部装甲板上安装有操纵杆,右前方有油门踏板、燃油分配开关和预压泵开关,在启动引擎时,驾驶员必须将燃油分配开关置于通位,并接通预压泵。驾驶员的右边有变速操纵档位选择器,上有两个手柄,一个方向选择手柄,一个单位选择手柄。在驾驶员的左边还有手动制动操纵手柄,在其附近还安装有各系统的电气操纵系统。


战斗室位于坦克中部,炮塔前部中间安装有火炮,火炮右侧安装有并列机枪,炮塔内有两名乘员(车长和炮长),其中车长位于炮塔内火炮的右侧,在车长舱盖的四周设有5个观察镜,指挥塔前方安装有1具周视瞄准镜,在周视瞄准镜的后面和车长舱盖右侧各有1个高射机枪枪架;炮长位于火炮的左侧,炮长舱盖前面有1具观瞄镜。


动力传动室位于坦克后部,与战斗室以装甲隔板隔开。动力系统可整体吊装,布局紧凑,与以往的坦克相比,98式坦克的战斗室加大了使用空间,为日后安装更大口径的坦克炮保留了余地。

三:武器系统

早在70年代,我国科研人员就展开了大口径坦克炮的研发工作,先后研发成功了120毫米、125毫米和130毫米等多种口径的坦克炮。在三代坦克炮口径的选择问题上,曾经有120毫米和125毫米两种口径之争。从实际情况看,120毫米高膛压滑膛炮的性能并不比125毫米坦克炮逊色,甚至某些性能上还优于125毫米坦克炮。由于98式坦克在设计时参考了苏式t-72坦克的许多技术特点,并直接借鉴了其自动装填机,这主要是为了大幅缩短研发周期。重新研发适用于120毫米火炮的新型自动装填机,在增加坦克设计难度的同时,坦克的整体设计也必须做较大修改。再者,120毫米炮弹为整装式结构,这就意味着与其配套的自动装填机体积不会太小,会给炮塔内的安装划定难以逾越的技术鸿沟。从目前西方安装有自动装弹机的法国勒克莱尔坦克和日本90式坦克看,其尾舱式自动装弹机的结构都比较复杂。我国89式120毫米自行反坦克炮的尾舱就安装有半自动装弹机。尽管提高了射速,但单从89式自行反坦克炮庞大的炮塔就可对其内部半自动装弹机的体积和复杂程度窥之一二。

从防护上讲,虽然西方坦克大都实现了弹药隔舱化,但在战场上采用尾舱式炮塔的坦克的生存能力不见得就比采用炮塔吊篮式自动装弹机的坦克高多少。单从弹药被命中的几率看,将弹药布置在尾舱的坦克要高于布置在车体内的坦克。另外,随着整装弹药重量的不断增加,造成装填手工作负荷不断增大,以目前坦克炮向大口径化发展的趋势看,在坦克上实现弹药的自动装填已成为必然。

我国前后发展了120毫米和125毫米反坦克弹药,前者采用整装式结构,后者采用了分装式结构。125毫米坦克炮早在1985年就研发成功,经不断改进,定型后的125毫米坦克炮的膛压已高于120毫米坦克炮。最终安装在98式坦克上的是zpt-98式50倍径125毫米高膛压光膛坦克炮。炮声身采用高强度 pcrni3nov,炮口动能比俄罗斯2a46m-1型125毫米坦克炮提高近45%,比“豹”2a5和m1a1/a2坦克上的rh-120型120毫米坦克炮高近30%。由于对身管实施了液力自紧技术,从而满足了高膛压火炮对身管强度的要求。为提高身管的耐烧蚀磨损寿命,火炮采用全膛镀铬工艺,使其寿命达到700发穿甲弹的水平,接近世界先进水准。为增强热防护效率,身管上安装了双层铝板气隙式热护套,防护效率为70%。


与俄罗斯2a46m-1型125毫米光膛坦克炮一样,ztp-98型坦克炮的炮闩也为横楔式,由冲杆弹簧式半自动控制,其上装有机械和电气式双功能击发系统。火炮反后坐装置为下置式,由带液量调节的筒式后坐节制杆式驻退机以及带针形杆复进节制器的三筒液气式复进机组成。火炮的药室长880毫米,正常后坐距离为280毫米~320毫米,最大后坐距离为330毫米。火炮身管质量为2.02吨,炮闩质量为72公斤,回转部分质量为2.6吨。火炮身管的抗弯强度为4320牛顿/米,厚度公差为0.6毫米,工艺加工弯曲度为0.7密耳,自由误差为0.18密耳。射击精度比俄式2a46m-1提高了25%。


zpt-98型坦克炮的摇架呈箍形,底座长1500毫米。底座上设有两条后坐滑轨,前滑轨为铜质环形衬筒,衬筒与炮身之间的安全膨胀间隙为0.3~0.9毫米,用于补偿身管射击时产生的热膨胀量。后滑轨由位于炮尾环和摇架上的轨道支架构成。可快速拆卸的摇架颈部由4颗螺栓固定。楔形半自动炮闩设在火炮上方,开闩力为245牛顿。车内加装一个驻退器和复进机液量可见控制装置,可在火炮不进行人工后坐情况下检查液量。另外,在火炮炮口端面装有前瞄准镜垫片,炮长借此可在车内迅速调整火炮。根据需要,火炮可用电点火装置、电击发和机械式手动击发射击。火炮可前抽更换,更换可在1小时内完成。

zpt-98型坦克炮配备的弹种包括采用半可燃药筒的(使用新型太根发射药)钨/铀合金尾翼稳定脱壳穿甲弹、尾翼稳定破甲弹和尾翼稳定多功能杀伤爆破榴弹,弹药基数为41发,其中2发置于自动装弹机的旋转输弹机内,19发放置在战斗室的各弹药箱内。在发射第三代钨合金尾翼稳定脱壳穿甲弹时(初速为1780米/秒),可在2000米距离击穿850毫米厚的均质装甲,而最新型特种合金穿甲弹(贫铀穿甲弹)在该距离上的穿甲厚度可达到960毫米,其弹芯长径比为30:1。为强化反坦克作战能力,98式坦克还配备了多功能榴弹,此乃增加装药的高爆型,威力较大,足以使坦克丧失战斗力。另外,98式坦克还配有仿俄制斯维尔河/反射9k119型(西方称at-11“狙击手”)雷射驾束制导炮射飞弹系统,车内一般携带有4枚飞弹。经过改进,新型炮射系统在98式坦克的炮长瞄准具内装有雷射发射机,飞弹的发射装药加长,全弹质量也有所增加。该弹可针对某种攻击情况(如静止发射攻击),选择复杂的飞行轨迹,低空飞向目标。


98式坦克的自动装弹机仿自俄式坦克,该系统由旋转输弹机、弹匣提升机、推弹机、药筒底壳抛出机构、火炮电机闭锁器、记忆装置、自动装填机配电盒、装弹操纵台、自动装填机操纵台、弹量指示器和全套电气系统安装组成。自动装弹机的装填角固定在4度30分,每发弹的装填时间为8秒。在自动装填方式时,98式坦克的主炮射速为8发/分,采人工装填,射速降为1~2发/分。试验证明,该自动装填机的间隔故障率为千分之三。目前,更新型的性能优良、使用可*、操作方便的装弹机系统已研发成功,将装备在98改进型坦克上。


98式坦克的辅助武器包括1挺86式7.62毫米并列机枪,安装于火炮右侧,采遥控电击发,弹链供弹,每条弹链内装250发弹,总共备弹2000发。车长指挥塔上装有1挺qjc88式12.7毫米高射机枪,由车子在炮塔外手动操纵,用单倍准直瞄准镜,对空中目标的最大表尺射程为1.5公里,俯仰范围为-4~+75度,战斗射速为80~100发/分,备弹300发,分装在5条弹链中。为了方便射击,在98式坦克的炮塔上共设有3个高射机枪枪架,其中车长指挥塔前方和右侧各有一个,炮长舱门左边设有1个。另外,3名乘员各配有1支56c型或95式短突击步枪。


四:火控系统


98式坦克上安装的是下反稳像式火控系统,该系统属指挥仪型数字式坦克火控系统,主要由昼夜观瞄、测距三合一的下反稳像式瞄准镜、火控计算机、控制盒、耳轴倾斜传感器、炮塔水平角速度传感器、横风传感器、炮控分系统组成。该系统与简易式火控系统的差别在于其光学瞄准线与火炮相互独立稳定,以炮长瞄准线作为稳定的基准,火炮随动于炮长瞄准线。下反稳像式火控系统是通过一个二自由度陀螺仪稳定瞄准镜中的下反射棱镜来实现炮长瞄准线的双向稳定。在瞄准状态时,炮长操作操控台驱动瞄准镜的瞄准线,使其瞄准跟踪目标,而火炮随动于瞄准线。当炮长在坦克行进间从瞄准镜向外观察目标时,瞄准镜中的目标和背景几乎是不动的,极大的方便了炮长在坦克行进间进行射击,而且射击时只需一次瞄准。使用时,炮长将瞄准镜标志瞄准目标中央并发射雷射测距后,目标不会出现扰动,炮长只需继续瞄准目标就可以射击。另外,火控系统中还配有火炮重合射击装置,当火炮调到计算机计算出的瞄准角和方位前置角的位置时,该装置会自动输出允许射击讯号,如果此时炮长已经按下射击按钮,火炮会自动射击。由于该下反稳像式火控系统是炮长瞄准线在高低向和水平向都稳定的,因此98式坦克不仅能在静止时以较高的命中率射击固定和活动目标,而且还可以在行进间以较高的首发命中率射击固定和活动目标。为提高坦克的作战能力,火控系统中增加了车长对火控进行操作的功能。在98式坦克车长指挥塔前方,有一具可360度旋转观察的上反式周视瞄准镜。该瞄准镜与炮长瞄准镜一样,均可在高低和水平方位上独立稳定,并有雷射测距和夜视功能,可独立稳定的搜索、选择和瞄准目标。车长可以进行目标指示,当炮长完成对一个目标射击后,车长可调转炮塔,使炮长捕捉车长选定的目标射击。此后,车长可继续搜索新的目标。如果车长突然发现对己方威胁较大的目标时,可立即调转火炮和炮塔,当火炮瞄准线与车长瞄准线重合时,炮塔停止转动,这就实现了超越调炮功能。如车长需了解炮长正在执行的任务时,可按下监视炮长按钮,此时车长瞄准线与炮长瞄准线重合,车长镜停止转动,车长镜和炮长镜观察同一目标,从而实现车长监视炮长功能。


98式坦克的车长和炮长无论昼夜都具备行进间射击固定和静止目标的能力,射击反应时间短,当静对静时≤5秒,静对动时≤秒,动对动时≤9秒。经测试,98式坦克在2000米距离上的首发命中率在85%以上。为适应错综复杂的战场环境,98式坦克的火控系统还可以降级使用。当稳像部分出现故障时,该系统还可作为自动装表简易式火控系统使用;假如自动装表简易式火控系统也出现故障,还可以用人工装定表尺进行瞄准射击。


近几年,由于在火控系统关键技术上取得突破性进展,我国先后研发成功了多种自动跟踪火控系统和瞄导合一的大死循环式火控系统。在98式改进型坦克上,安装的是最新型瞄导合一的大死循环火控系统。瞄导合一大死循环火控系统是一种可对射击结果实施自动校正的火控系统,假如首发射??偏差的距离和角速度自动输入火控计算机进行下一发弹的修正计算后立即射击,大大提高了次发命中率。在大死循环火控系统中,如何自动的实时测出弹着点偏差并进行自动校正,是应用这种火控系统的前提和技术关键。系统中必须有能自动跟踪目标和自动跟踪弹丸的装置和传感器。目前跟踪目标用自动跟踪器实现,自动跟踪器可用闭路电视和热像仪实现;自动跟踪弹丸采用脱靶距离传感器(如无线电定位传感器及观点传感器等)实现。由于热像仪可以根据目标的热特征跟踪目标,又能利用弹丸的热特征自动跟踪弹丸,因而也可以作为自动跟踪器和脱靶距离传感器。由于大死循环火控系统是建立在对脱靶距离实时自动校正的基础上,因而要求火炮要有行高的初速,这样弹丸飞行的时间就能缩短利于迅速校正射击。大死循环火控系统可明显提高第二发弹的命中率,用于射击越野行进的高速目标效果明显。在测试中,98改进型坦克在2000米距离对运动目标进行的46次第二发补射中(人为设定),命中率为100%。

五:夜视系统


98式坦克上的炮长用热像仪是解放军装备的比较先进的热成像系统,该热像仪的探测器为SPRITE探测器,其光敏面是粘贴在蓝宝石衬底上以光刻掩膜而成底8条蹄镉汞芯片。SPRITE探测器与单元数组探测器相比,其优点是探测器就完成了时间延迟积分处理,即signal processing in the element,SPRITE也由此得名。SPRITE探测器必须在80K左右且真空中才有良好的性能,所以它需要封装在杜瓦瓶里,由制冷机对杜瓦瓶进行制冷。98式坦克上炮长热像仪采用分置式斯特林制冷机制冷,连续工作时间在12小时以上,试用探测器工作的制冷时间为5分钟。热像仪全重42公斤,采用串并联方式扫描,视场为5.6X3.8度(11.4倍);12X8度(5倍)。在昼间对坦克目标的识别距离为2600米,夜间为2750米。


目前,我国已研发成功第二代热像仪,该热像仪不需光电扫描,由探测器直接接受全视场的热辐射讯号而成凝视图像,因此也称凝视焦平面热像仪。其作用距离可达7~9公里,灵敏度和分辨率比第一代热像仪有很大提高,且结构紧凑,造价低廉,平均无故障时间为4000小时,在能见度只有100米的恶劣环境中对目标的发现距离为4000米,识别距离3100米。该热像仪已安装在98改进型坦克上。


六:防护性能


98式坦克的外形低矮(不到2.3米),车首和炮塔正面采用可更换式新型复合装甲。其中车首用均质轧制装甲焊接而成,重要部位采用迭型陶瓷复合装甲加强。首上装甲板为多层复合装甲,具体结构为钢-玻璃纤维板-超硬钢-钢,总厚度为220毫米,倾角为22度,其防护能力相当于500~600毫米均质装甲。车体首下装甲板厚度为80毫米,挂装有两块大型钢质塑料板,也可以挂一具推土铲。车体两侧安装有8毫米厚夹布橡胶履带裙板,前护板和侧裙板对带倾斜引信的反坦克地雷和破甲弹有一定防护作用。另外,为保护驾驶员的安全,其座椅悬吊在车体上,底部加强了防护装甲,两侧各焊接有一根垂直钢架,用以提高结构强度。98式坦克的炮塔装甲由复合材质和特种钢组成,两者间的夹层内还有特种材质,故又称间隙式复合装甲。其在2000米距离上可抗击穿甲能力在700毫米的动能穿甲弹和破甲能力在800毫米以上的战防弹。在1997年冬季进行的低温试验中,98式坦克经受了14发105毫米尾翼稳定脱壳穿甲弹的攻击,无一击穿坦克的前装甲。后来用T-72C坦克上的125毫米炮对其射击6次,依然无法击穿前装甲。


如果披挂上附加装甲,在车重增加0.7吨的情况下,98式坦克的抗APFSDS穿甲能力在830毫米以上,抗HEAT穿甲能力在1060毫米以上;在炮塔和车体上安装新型双防反应装甲后,抗APFSDS和HEAT的能力可达到1000~1200毫米。另外,98式坦克的侧屏蔽前端还装有反应装甲,顶部装甲也得以强化。


众所周知,坦克最薄弱的防护在炮塔顶部,在制导武器(尤其是攻顶弹药)比重日趋增重的今天,单纯依*坦克的硬防护已经无法完全满足坦克生存的要求。为进一步增强98式坦克的生存力,其上安装了反导软防护系统。该系统由JD-3红外干扰机、烟雾弹系统、雷射告警装置和控制系统组成。JD-3红外干扰机由红外发射机、电源和控制装置、控制板组成,系统总质量为75公斤。通常情况下,在坦克主炮两侧各装一台JD-3红外干扰机。JD-3红外干扰机的方位覆盖范围为主炮两侧22度方位角,高低覆盖范围是5度,在探测到来袭目标后2秒内发射0.7~2.5μm波段的红外脉冲辐射讯号。红外干扰机能够持续发射编码红外脉冲干扰讯号,使红外制导反坦克弹药的制导电路产生假讯号,可有效干扰“TOW”、“龙”、“霍特”等反坦克飞弹。


烟雾弹系统由94式烟雾发射器和97式烟雾弹组成。该系统可在3秒内在距离坦克50~80米处形成气溶胶烟雾屏障,对敌方的雷射目标指示器和雷射测距机产生屏蔽,对0.4~14μm波段具有较好的遮蔽作用,持续作用时间为20秒。试验证明,该系统可使“TOW”、“龙”、“小牛”、“地狱火”等反坦克飞弹的命中率降低75~80%;使“霍特”、“米兰”等反坦克飞弹的命中率降低2/3;使雷射测距机辅助射击的各种火炮命中率下降2/3。


除软防护系统外,98式坦克上还可以安装新型主动式防御系统。该系统由控制装置、毫米波雷达、发射系统组成,各子系统采用了模块化设计,可以快速更换。该系统的工作原理是:车长将系统置于工作状态,此时雷达采用监视工作状态。当探测到距坦克50米之内、在规定的范围内飞行的目标时,雷达自动转换成跟踪模式,并向火控计算机提供目标的弹道数据,由火控计算机确定来袭弹药是否可能命中坦克。如判断来袭弹药会命中坦克,雷达则提供精确跟踪数据,计算机确定防御弹药的发射位置和时间,在来袭弹药距坦克1.5~4.2米处爆炸,击中来袭弹药,使来袭弹药的弹头提起爆炸或使其偏离飞行轨道。如判断来袭弹药不构成威胁,雷达则恢复到监视状态。主动防御系统可对付速度为70~700米/秒的来袭目标,系统重新做好准备只需0.2~0.4秒。该系统对协同作战的步兵危险区为20~30米。另外,该系统可自动识别假目标,如飞鸟、子弹、炮弹破片和己方发射的炮弹或飞弹等。主动防御系统可安装在多种装甲车辆上,可将装甲车辆的生存能力提高近2倍。安装该系统的坦克不会对其他坦克产生电磁干扰,系统本身也有良好的反电子干扰能力。


在98式坦克的内部安装有集体三防装置和自动灭火抑爆系统,战斗舱、驾驶舱及其舱盖的内壁加装有一层防辐射衬层,可降低r射线对乘员的伤害。此外,在坦克被穿甲弹击中时还可以防止乘员受到从内部崩落的碎片的伤害。车体和炮塔均涂有三色迷彩涂层。


在波斯湾战争中,伊拉克的装甲车辆由于没有装备预防“二次”效应的有效设备,导致了惨重伤亡(尤其是较为先进的T-72坦克)。经测试,坦克战斗舱内,由HEAT射流引起的车内油气混合物爆炸,会在140毫秒~240毫秒内形成0.35~1.4兆帕的超压,有的甚至达到2兆帕,伴随爆炸形成的热辐射强度可达6~10瓦/平方公分。当弹丸穿透装甲板时,车内人员很容易受到三种主要危害:压力冲击、皮肤烧伤和毒剂效应。对人体而言,假如作用于身体的压力时间超过50毫秒,0.1兆帕以上的超压通常会造成肺部永久性损伤。0.3兆帕以上的超压将使人员的死亡率达50%。当超压值达到0.4~0.5兆帕时,人员将必死无疑。按医学要求,皮肤以下0.08毫米深处的温度超过43.5摄氏度,身体裸露部位将遭受难以恢复的2度烧伤。或者用热辐射计表示,即10瓦/平方公分强度的热辐射作用在皮肤上的时间超过100毫秒时,所引起的皮肤烧伤将会达到1度。除了超压、皮肤烧伤外,毒剂对乘员的伤害也不能忽视。在残酷的战场环境下,当车辆中弹时,车内乘员处于高度紧张、担忧状态。人员体内肾上腺素将会增高,这会增加人体对毒性物质的敏感性。毒性物质来自爆炸后的产物、燃烧的产物及热分解产物。爆炸产生的毒性物质取决于来袭弹药的性质,燃烧和热分解产生的毒性物质的多少取决于感受穿透射流的敏感速度和灭火的持续时间。综上所述,装甲车辆内一旦发生“二次效应”,对车内乘员的伤害将是致命。因此,给装甲车辆配备高效的灭火和抑爆系统,预防“二次效应”,对提高坦克在战场上的生存能力有着极其重要的作用。

在装甲车辆内,有效的灭火抑爆系统应该具备敏感的探测器、快速的控制系统和有效的灭火剂,这样才能有效制止爆炸和彻底地避免“二次效应”。通过研究人员地反复试验证明。如在130毫秒内扑灭坦克内的各种火灾,就能够避免各种油气混合物的爆炸。在预防二度烧伤时,只要10瓦/平方公分热辐射作用在皮肤表面的时间不超过100毫秒,就能使乘员避免遭受较为严重的二度烧伤。但是,如果压力的作用在50毫秒以上时,同样会造成人体的各部位损伤甚至死亡。因此,自动灭火抑爆系统的反应时间越快、抑制超压和避免烧伤效果就越好。


早在60年代初期,我国就展开了装甲车辆自动灭火系统的研发,但由于各种原因进展缓慢。直到中越边境冲突后,战场上的血的教训使解放军提高了对装甲车辆自动灭火装置作用的认识并产生了迫切要求,自动灭火系统的研究工作因而加快。1980年,我国自行研发了80式自动灭火装置并装备于各型装甲车辆上,经实践证明,使用效果良好。但是,该系统还不具备抑爆功能。因此,80年代初,我国引进了“SAFE”系统,并很快完成了样机试制和全部系统的国产化。后来,在其基础上我国又发展了更先进的自动抑爆系统。98式坦克上装备的是92式自动灭火抑爆系统,该系统由关系探测器(6个)、控制盒、灭火瓶(4个)、紧急开关和电缆组成。??油气混合物爆炸,并能够将油气爆炸产生的压力限制在0.1兆帕以内,这样能够使乘员的皮肤烧伤程度限制在1度以下,故可以达到灭火抑爆作用,防止“二次效应”发生。在灭火瓶中,装有液态的“哈隆”1301灭火剂,并充满氮气,阀体直接装在瓶口上,不使用分布管路,这样可以极大的缩短喷射时间。


七:光电通信及对抗系统


调频通信是扩展频谱(扩频)通信的一种,作为通信电子对抗的重要手段被广泛应用于装甲车辆的通信系统。98式坦克上采用的是新型VHF-2000型坦克通信系统,该系统具备良好的电子对抗性能,系统通用性好,便于使用维修,可*性高,电磁兼容性及同台多机工作性能良好等特点。在98式坦克炮塔后部右侧,有一具敌我识别与雷射通信系统,其雷射敌我识别与雷射光波作为载波传递讯号。这是一套小型化的一机多功能的车载系统,供车长用于敌我识别、发射数字指令、进行语音通信,并可发展用于雷射搜索。系统的全方位接收机控制头也可用于对0.9~1.06μm雷射告警器。该系统可抗光、电、磁干扰,工作距离≥3.6公里,高低向-10~+45度(与车长周视镜相同),水平向360度,识别一次目标时间≤0.6秒,有60种敌我识别密码。系统能显示敌我识别结果。数字通信指令、正在通信与等待通信车的概略方位。


在坦克炮塔尾舱右侧顶甲板上方,装有9602型GPS导航定位接收天线,负责接收并放大导航卫星发射的高频讯号,并变成中频讯号送入接收机。在炮塔尾舱内右侧甲板上,接收并处理来自天线的中频讯号盒来自GPS接收机显示控制器的控制指令,其显示控制器安装在炮塔内右侧座圈下方,显示导航信息并输入输出控制指令。9602型GPS卫星导航仪是二通道的C/A码接收机,可对四颗卫星按时分制进行时序观测,采用L1载波上调制的C/A码进行续距测量,由导航处理机实时求出三维位置和速度。如果可供观测的卫星只有三颗时,接收机可以将人工输入的高程或上次三维定位得到的高程作为已知值,进行二维定位,实时求出经纬值,对于军事用户而言,可将经纬值交换成我国九四军用网络坐标值。9602型GPS接收装置被动式导航、无积累误差、保密性较好。可全天候向乘员提供坦克所处位置的三维坐标式军用网络直角坐标,能提供坦克的行进方位、行进速度等数据。输入目标可提供目标的方位和距离。输入多个航路点后可建立航线,并对偏航距离和接近目标距离进行报警。设备本身具备进行共况自检和故障诊断功能。9602型GPS属单一的粗码定位系统,其精度目前相对较低(100米),对于有些战术要求还不能满足。“GLONSS/GPS”兼容型导航定位位置在我国已研发成功。它的精度可以达到20米。单一GPS只是过渡产品,最终要被双G兼容机所取代,一旦98改进型坦克配备了双G兼容机,则可与车内电台、雷射测距等设备连接起来,构成车际信息系统,可实现战场管理,火力支持、目标营救、敌我识别等多种战术任务,届时98改进型坦克将成为解放军最新的数字化坦克。


在98式坦克炮长舱门后部基座上,装有一具新颖独特的装置,此即为雷射压制观瞄系统。由于红外干扰机的作用仅局限于干扰红外制导方式的飞弹,不能干扰其它方式制导的飞弹,要具备多功能干扰能力,就要为坦克配备多种不同的光电对抗设备。该系统在与敌方对抗时,能起到干扰和压制对方观瞄系统的作用。该系统供车长或炮长操作,能发射激光束对敌方观瞄体系进行压制、干扰。由于激光束固有的特性,既然能压制干扰观瞄系统,那么对人体的危害性是不言而喻的。特别是对于使用直视型光学观瞄镜对己方观瞄的敌方人员的眼睛,其杀伤效果特别明显。另外,雷射压制观瞄系统还可以对敌方使用可见光、近红外光电传感器的火控、制导系统(如雷射测距机、微光夜视仪、电视摄像头、观瞄镜等)实施干扰,使之饱和失效,甚至产生永久性损坏,即仪器致盲,从而失去战斗能力。同样,为预防敌方对己方实施雷射照射,98式坦克上的驾驶员均配有防雷射光镜。雷射压制观瞄系统由微机控制器、跟踪转台及随动系统、雷射压制仪、热成像干扰机(气体雷射发射机)组成。为实现车长、炮长遥控跟踪瞄准,对跟踪转台采用数字式位置死循环控制方式。该系统可360度全方位工作,俯仰角为-12~90度,跟踪角速度左右为45度/秒,俯仰40度/秒。从炮长(或车长)按下按钮到系统对准目标只需1秒钟。雷射输出能量为1000兆焦,脉冲重复工作频率为10次/秒,最大作用距离为4000米,系统连续工作时间为30分钟,激光器的寿命为120万次。

八:动力传动系统


长期以来,缺乏大功率引擎是制约我国主力坦克水平的一大技术瓶颈。经过不懈努力,我国在80年代末研发成功了多种1200马力的大功率柴油引擎。其中150HB系列的1200马力涡轮增压中冷式大功率柴油引擎的性能较为出色,被选中作为98式坦克的动力系统。可能是在设计时参考和借鉴了德国MTU公司的MB871ka501型引擎的设计理念,所以150HB引擎与其有着惊人的相似之处。

由于安装了大功率引擎,51吨重的98式坦克的单位功率达到了23.54马力/吨,最大公路时速高达70公里/小时,0~32公里加速时间为12秒。在输出功率相同的情况下,150HB引擎的质量比英国“挑战者”坦克上安装的CV12TVC-1200型引擎轻15%。


为适应装甲兵的发展要求,我国在150HB柴油引擎的基础上研发成功了具有世界水准的150HB1500马力大功率引擎,其研制时瞄准的目标九四德国的MT883型引擎。目前,该引擎已安装在98改进型坦克上。经测试,98改进型坦克的最大公路时速和最大越野时速分别为80公里/小时和60公里/小时。


在98式坦克上仍采用传统的机械传动、液力控制装置。传动装置由传动箱、两个侧变速箱和同轴侧传动器组成。侧变速箱为行星式,带摩擦离合器,采用液力操纵,有7个前进档和1个倒档,每个变速箱内有2个闭锁离合器和4个机械式制动器。


在行走部分上,98式坦克采用两条双销挂胶履带(每条由85块履带板组成,总质量为2.1吨,使用寿命为10000公里)、6对直径为730公里的双缘路轮、两对挂胶托带轮、两对挂胶托边轮以及主动轮和诱导轮组成,主动轮在后,诱导轮在前。在第一、第二和第六路轮上安装有液力套筒式避震器和“Z”形轴避震器。悬吊装置的扭杆沿底甲板横向布置,操纵装置的拉杆沿侧甲板布置。由于对扭杆进行了改进,路轮行程增至340毫米,从而使车辆平均行驶速度提高了12%,从停车状态加速到42公里/小时只需10秒。

八:改进

由于98式坦克在防护、火力和火控方面已具相当水准,提高动力系统的可*性问题就显得日益突出。由于引擎体积的问题,98式坦克的动力传动室采用纵置布局,造成车体过长和过重,阻碍了其性能提升。在安装相同功率引擎的情况下,北方工业公司新近推出的MBT-2000型坦克由于改进了引擎并采用横置布局,其车体长度仅为6.487米,使得战斗全重为46吨的MBT-2000的车体防护性能反而优于51吨重的98式坦克。所以,在98式坦克投入大规模生产前,为其更换全新的底盘已势在必行。经过长时间考验证明,MBT-2000型坦克的动力传动系统的可*性是目前我国国内最好的,与世界先进水平差距较小。如将98式坦克的炮塔略加改进后安装在MBT-2000坦克的底盘上,将会使整车性能有大幅提高。我国科研人员曾对一辆98式坦克进行了改进,将其炮塔安装在MBT-2000坦克底盘上,改装后的坦克命名为98改型坦克。该坦克战斗全重为50吨,车体前部防护性能相当于650毫米厚的均质装甲。为对付更大的威胁,在必要情况下可以在炮塔的前装甲上焊接楔形复合装甲块,可以进一步提高炮塔的防护能力。有关单位曾将一辆98式坦克进行了类似的试验,结果较为满意。


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Max Planck Institute of Microstructure Physics

Scientific Profile, History, People, Cooperation of Max Planck Institute of Microstructure Physics

Max Planck Institute of Microstructure Physics
Scientific Profile

Experimental and theoretical research carried out at the Max Planck Institute of Microstructure Physics is primarily focussed on solid state phenomena that are determined by small dimensions and surfaces and interfaces. The investigations concentrate on establishing relations between the magnetic, electronic, optical, and mechanical properties of solids and their microstructure. Thin films and surfaces are investigated as well as nanocrystalline materials, phase boundaries and defects in bulk crystals. The results of the research will provide the necessary information for creating new and improved functional or structural materials in application areas such as sensorics, opto- and microelectronics.

History

The Max Planck Institute of Microstructure Physics was founded in 1992 as the first institute of the Max-Planck-Gesellschaft in the eastern part of Germany based on the previous Academy of Science Institute of Solid Sate Physics and Electron Microscopy. The institute consists of two experimental departments (I and II) and the theory department. A new laboratory building for the experimental departments, including also workshop facilities and a hall for special experiments, were put into use in September 1997. Two other buildings were reconstructed and are available since the beginning of 1999. Guest houses of the institute was opened in 1995 and in 1999.


People

The staff of the institute including scientific, technical and administrative personnel, comprised 99 positions, partly occupied by non-tenured personnel (19 scientists and 4 technicians). In addition, 44 co-workers have been funded by outside sources (incl. 16 graduate students) and 26 graduate students and 38 postdocs by MPG fellowships. Furthermore, 99 scientists (61 person-years) from abroad worked at the institute (incl. 26 graduate students).

Cooperation

A joint German-French research association in the field of magnetic thin films called "Laboratoire Européen Associé" (LEA) and collaboration based on an official agreement in the area of wafer bonding technology between the Research Center of Advanced Science and Technology (RCAST) at the University of Tokyo and the Max Planck Institute in Halle are well established now. Furthermore, starting on April 4, 2005 the Max Planck Research School for Science of Nanostructures together with Martin Luther University Halle Wittenberg and the Institute for Mechanics of Materials, Halle was established.

For more information, please go to this website:
http://www.mpi-halle.mpg.de/mpi/mpi_f_abo.html

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A Maven in Electronic Thin Film Science--Professor King - Ning Tu


Professor; B.S., National Taiwan University; M.S., Brown University; Ph.D. in Applied Physics, Harvard University(1968) ; Senior Manager of Materials Science Department at IBM T.J. Watson Research Center; Science Research Council Senior Research Fellow and The Royal Society Guest Research Fellow at Cavendish Laboratory, UK; Fellow of American Physical Society; Fellow of the Metallurgical Society; Overseas Fellow of Churchill College; Application to Practice Award of the Metallurgical Society; Alexander von Humboldt Research Award for senior US scientists; President of the Materials Research Society in 1981, Member of Academia Sinica, Republic of China.

As of April 2007, the total number of citation N = 10186.
h-factor = 56.
a-factor = N/(h x h) = 3.25.


RESEARCH DESCRIPTION
Our research interest is in wafer-based and flux-driven materials science. Modern microelectronic, opto-electronic, bio-sensor, and MEMS devices are built on wafers, involving the growth or removal of mono-layers of atoms from the wafer surface or an interface. They are open systems, in which the initial wafer surface area is constant and the flux-driven processes can come from atoms, molecules, or energy beams. Specifically, we concentrate on interfacial reactions, including metal-Si reaction, Cu-Sn reaction in solder joints, nanoscale interdiffusion and reaction, polarity effect of electromigation on interfacial reaction, and kinetic theories of interfacial reaction.

Our major research areas are (1) Cu-Sn reactions in Pb-free solder metallurgy for electronic packaging technology, (2) Advanced materials reliability problems of microelectronic devices, especially the interaction among electromigration, chemical reaction, and mechanical stress in flip chip technology, and (3) Nanoscale interdiffusion and reactions. In addition, we also conduct exploratory research on (4) Interaction of implanted metallic atoms with dislocations and grain boundaries in Si, and (5) Kinetic theories of interdiffusion and reactions.

On Pb-free solder metallurgy, we study the applications of eutectic SnAg, SnAgCu, SnCu, SnZn as solder bumps to flip chip technology. The wetting reaction and solid state aging of these Pb-free alloys with thin film under-bump-metallization are of interest. Due to the large difference in thermal expansion coefficients between the Si chip and its packaging substrate, the solder joints are stressed. In turn, the stress affects chip-packaging interaction and the integrity of Cu/ultra low k multi-layered interconnect structure on the chip. The diameter of the solder balls is approaching 50 mm, so electromigration becomes a reliability issue. The advanced materials reliability problems due to a combined action from chemical, electrical, and mechanical forces in flip chip technology will be studied systematically. Electromigration induced microstructure evolution and grain rotation in Pb-free solder alloys requires investigation. A unique nature of most Pb-free solders is that they are very rich in Sn, hence the old topics of Sn whisker, Sn pest, and Sn cry are of interest again. We shall combine micro-diffraction in synchrotron radiation, focused ion beam imaging, and cross-sectional transmission electron microscopy to study these issues. In optical packaging, we interest in how to wet an optical fiber by molten solder and how to achieve high precision alignment by solder joints.

On interconnect technology, our research emphasizes the effect of current crowding on vacancy and solute diffusion in electromigration. The nature of the electromigration force along the direction of current density gradient, i.e., normal to the current flow, will be explored. Why actual failures tend to initiate in the low current density regions will be studied. The effect of current crowding on joule heating as well as on stress concentration will be analyzed. The nature of back stress induced by electromigration and whether or not there is back stress in Cu interconnect will be investigated.

On nanoscale interdiffusion and reactions, we study the reaction of ultra thin metal films on nano Si wires and vice versa, and the nanoscale explosion in multi-layered nano-thickness thin films. Hollow nanostructure formation based on the Kirkendall effect will be investigated.

On extended defects in Si, we study the nucleation, growth, and ripening of dislocation loops formed by ion implantation and post-implantation annealing. The interaction of these loops with metallic atoms such as Ni and Co will be investigated. We also investigate the nano-grid of screw dislocation network, or very small angle twist-type grain boundary in Si bicrystals formed by wafer bonding. Again we examine the interaction of implanted metallic atoms with these dislocation networks.

Kinetic theory of phase transformations in open systems under the constraint of a constant surface area applies to phase changes on a wafer or on a given area of surface or interface will be developed. For example, the constraint of constant area is fundamental to the ripening of hemispherical scallops during the reaction between molten solder and Cu. The existence of nano channels between the scallops will be studied. The constraint of constant area also applies to the linear rate of grain growth in thin film deposition.


2006-2007 Publications:

A. M. Gusak, G. V. Lutsenko, and K. N. Tu, “Ostwald ripening with non-equilibrium vacancies,” Acta Mat., 54, 785-791 (2006).



Lingyun Zhang, Shengquan Ou, Joanne Huang, K. N. Tu, Stephen Gee, and Luu Nguyen, “Effect of current crowding on void propagation at the interface between intermetallic compound and solder in flip chip solder joints, “ Appl. Phys. Lett., 88, 012106 (2006).



S. W. Liang, T. L. Shao, Chih Chen, Everett C. C. Yeh, and K. N. Tu, “Relieving the current crowding effect in flip-chip solder joints during current stressing, “ J. Mater. Res., 21, 137-146 (2006).



M. O. Alam, B. Y. Wu, Y. C. Chan, and K. N. Tu, "High electric current density induced interfacial reactions in the micro Ball Grid Array (µBGA) solder joint" Acta Mat., 54, 613-621 (2006).



J. W. Nah, Fei Ren, K. N. Tu, Sridharan Venk, and Gabe Camara, “Electromigration in Pb-free flip chip solder joints on flexible substrates,“ J. Appl. Phys., 99, 023520 (2006).



Young-Woo Okm Tae-Yeon Seong, Chel-Jong Choi, and K. N. Tu, “Field emission form Ni-disilicide nanorods formed by using implantation of Ni an Si couples with laser annealing,” Appl. Phys. Lett., 88, 043106 (2006).



Z. H. Gan, W. Shao, M. Y. Yan, A. V. Vairagar, T. Zaporozhets, M. A. Meyer, A. Krishnamoorthy, , K. N. Tu, A. Gusak, E. Zschech, and S. G. Mhailkar, “Understanding the impact of surface engineering, structure, and design on electromigration through Monte Carlo simulation and in-situ SEM studies,” in “Stress-induced phenomena in metallization,” AIP Proceedings of 8th Workshop on Stress-induced Phenomena in metallization, Dresden, Germany, vol. 817, p.34-42 (2006).



M. Y. Yan, K. N. Tu, A. V. Vairagar, M. A. Meyer, H. Geisler, A. Preusse, and E. Zschech, “Effect of overburden thicknss on the copper microstructure of dual-inlaid interconnect structures,” AIP Proceedings of 8th Workshop on Stress-induced Phenomena in metallization, Dresden, Germany, vol. 817, p. 211-216 (2006).



M. Y. Yan, K. N. Tu, A. V. Vairagar, S. G. Mhaisalkar, and Ahila Krishnamoorthy, “A direct measurement of electromigration induced drift velocity in Cu dual damascene interconnects,” Microelectronics Reliability, 46, 1392-1395 (2006).



K. N. Tu, M. Y. Yan, Fei Ren, Joannne Huang, Emily Ou, L. Y. Zhang, and J. W. Nah, “Electromigration in flip chip solder joints,” AIP Proceedings of 8th Workshop on Stress-induced Phenomena in metallization, Dresden, Germany, vol. 817, p. 327-338 (2006)



Jae-Woong Nah, Fei Ren, Kyung-Wook Paik, and K. N. Tu, “Effect of electromigration on mechanical shear behavior of flip chip solder joints,” J. Mater. Res., 21, 698-702 (2006).



Annie T. Huang, A. M. Gusak, K. N. Tu, and Yi-Shao Lai, “Thermomigration in SnPb composite flip chip solder joints,” Appl. Phys. Lett., 88, 141911 (2006).



S. W. Liang, Y. W. Chang, T. L. Shao, Chih Chen, and K. N. Tu, “Effect of three-dimensional current and temperature distribution on void formation and propagation in flip chip solder joints during electromigration,” Appl. Phys. Lett., 89, 022117 (2006).



Xi Zhang, K. N. Tu, Y. H. Xie, C. H. Tung, and S. Y. Xu, “Single-step fabrication of Ni films with arrayed macropores and nanostructured skeletons,” Adv. Mater., 18, 1905-1909 (2006).



Xi Zhang, K. N. Tu, Y. H. Xie, and C. H. Tung, “High aspect ration Ni structure fabricated by electrochemical replication of hydrofluoric acid etched Si,” Electrochemical and Solid State Letters, 9, C150-C152 (2006).



R. Agarwal, Shengquan E. Ou, and K. N. Tu, “Electromigration and critical product in eutectic SnPb solder lines at 100 C,” J. Appl. Phys., 100, 024909 (2006).



Annie T. Huang, K. N. Tu and Yi-Shao Lai, “Effect of the combination of electromigration and thermomigration on phase migration and partial melting in flip chip composite SnPb solder joints,” J. Appl. Phys., 100, 033512 (2006).



Fei Ren, Jae-Woong Nah, K. N. Tu, Bingshou Xiong, Luhua Xu, and John H. L. Pang, “Electromigration induced ductile-to-brittle transition in lead-free solder joints,” Appl. Phys. Lett., 89, 141914 (2006).



Luhua Xu, John H. L. Pang and K. N. Tu, “Effect of electromigration-induced back stress gradient on nano-indentation marker movement in SnAgCu solder joints,” Appl. Phys. Lett., 89, 221909 (2006).



Fan-Yi Ouyang, K. N. Tu, Yi-Shao Lai, and Andriy M. Gusak, “Effect of entropy production on microstructure change in eutectic SnPb flip chip solder joints by thermomigration.” Appl. Phys. Lett., 89, 221906 (2006).



Xi Zhang and K. N. Tu, “Preparation of hierarchically porous nickel from macroporous silicon,” J. of Am. Chem. Soc., Communication, 128 (47), 15306-15307, Nov. 2006.



Xi Zhang, F. Ren, M. S. Goorsky, and K. N. Tu, “Study of the initial stage of electroless nickel deposition on Si (100) substrates in aqueous alkaline solution”, Surface and Coatings Technology, 201 (6), 2724 -2732, Dec. 2006.



Jae-Woong Nah, J. O. Suh, K. N. Tu, Seung Wook Yoon, Vempati Srinivasa Rao, Vaidyanathan Kripesh, and Fay Hua, “Electromigration in flip chip solder joints having a thick Cu column bump and a shallow solder interconnect,” J. Appl. Phys., 100, 123513 (2006).



Zhenghao Gan, A. M. Gusak, W. Shao, Zhong Chen, S. G. Mhaisalkar, T. Zaporozhets, and K. N. Tu, “Analytical modeling of reservoir effect on electomigration in Cu interconnects,” J. Mater. Res., 22, 152-156 (2007).



Luhua Xu, Pradeep Dixit, Jianmin Miao, John H. L. Pang, Xi Zhang, and K. N. Tu, “Through-wafer electroplated copper interconnect with ultrafine grains and high density of nanotwins,” Appl. Phys. Lett., 90, 033111 (2007).



Chengkun Xu, Xi Zhang, K. N. Tu, and Y. H. Xie, “Nickel displacement deposition of porous silicon with ultrahigh aspect ratio,” J. of Electrochemical Society, 154(3), D170-D174 (2007).



K. N. Tu, Chin Chen, and Albert T. Wu, “Stress analysis of spontaneous Sn whisker growth,” J. Mater. Sci: Mater. Electron., 18, 269-281 (2007).



W. Shao, S. G. Mhaisalkar, T. Sritharan, A. V. Vairagar, H. J. Engelmann, O. Aubel, E. Zschech, A. M. Gusak, and K. N. Tu, „Direct evidence of Cu/cap/liner edge being the dominant electromigration path in dual damascene Cu interconnects,“ Appl. Phys. Lett., 90, 052106 (2007).



Xi Zhang, Zhong Chen, and K. N. Tu, "Immersion nickel deposition on blank silicon in aqueous solution containing ammonium fluoride", Thin Solid Films, 515, 4696-4701 (2007).



Jae-Woong Nah, Kai Chen, K. N. Tu, Bor-Rung Su, and Chih Chen, “Mechanism of electromigration-induced failure in flip chip solder joints with a 10 micron thick Cu under-bump-metallization”, J. Mater. Res., 22, 763-769 (2007).



Chengkun Xu, Mingheng Li, Xi Zhang, K. N. Tu, and Y. H. Xie, “Theoretical studies of displacement deposition of Ni into porous Si with ultrahigh aspect ratio”, Electrochimica Acta, 52, 3901-3909 (2007).



J. W. Jang, J. K. Lin, D. R. Frear, T. Y. Lee, and K. N. Tu, “Ripening-assisted void formation in the matrix of Pb-free solder joints during solid-state aging,” J. Mater. Res., 22, 826-830 (2007).







List of thesis students in the last five years
Ph.D. students:

Dr. Harqkyun Kim, 1996 Dissertation title: "Instability at wetting tip and wetting interface of Sn-based solders on Cu substrate." Now at BMR, Orange County, CA.

Dr. Jia-Sheng Huang, 1997 Dissertation title: "Polarity effect on failure of Ni and Ni2Si contacts on p+-Si and n+-Si under high current densities." Now at Agere, Alhambra, CA.

Dr. Patrick G. Kim, 1998 Dissertation title: "Wetting behaviors of Pb-based and Pb-free solders on Au, Pd, and Ni substrates." Now at Amkor Technology, Chandler, AZ.

Dr. Lowen Chow, 1999 Dissertation title: "Structure and mechanical propertes of low dielectric constant xerogel thin films" Now at Intel, Santa Clara, CA.

Dr. Chien-Neng Liao, 1999 Dissertation title: "Thermoelectric characterization of Si thin films in SOI wafers and thermal conductivity of low dielectric constant thin films." Now assistant professor at National Tsing Hua University, Hsinchu, Taiwan, ROC.

Dr. Chih Chen, 1999 Dissertation title: "Grain boundary structure in twist-type Si bicrystals made from SOI and dopant activation in SOI by high density currents." Now assistant professor at National Chiao Tung Univeristy, Hsinchu, Taiwan, ROC (starting 08/01/00).

Dr. Dawei Zheng, 1999 Dissertation title: “Measurement of local stress for microelectronics applications,” Now at Lightcrosss, Los Angeles, CA.

Dr. Chengyi Liu, 3/00, Ph.D. Dissertation on "Wetting behavior and electromigration of SnPb solders as a function of alloy composition." Now assistant professor at National Central University, Chungli, Taiwan, ROC.

Dr. Taek Yeong Lee, 2001 Dissertation title: "Electromigration and solid state aging of Pb-free flip chip solder joints and synchrotron radiation study of Sn whisker growth," Now at AT&T Bell Lab., Lucent Technologies, Murray Hill, NJ.

Dr. Peter Sangwoo Nam, 11/01, Dissertation title: "GaAs backside through chip via hole integration using inductively coupled plasma etching." Now at TRW, Redondo Beach, CA.

Dr. Woojin Choi, 2002 Dissertation title "Reliability of Pb-free solders in electronic packaging technology." Now at Intel, Chandra, AZ.

Dr. Hua Gan, 2004 Dissertation Title, “Polarity effect of electromigration on intermetallic compound formation in Pb-free solder V-groove samples.” Now at IBM T. J. Watson Research Center, Yorktown Heights, NY.

Albert T. C, Wu, 12/04, Ph.D. dissertation on "Electromigration and Microstructure Evolution in Anisotropic Conducting Tin Studied by Synchrotron X-ray Microdiffraction." Now at Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA.

Dr. Emily Shengquan Ou, 2005 Dissertation Tiltle, "The polarity effect of electromigration on intermetallic compound formation and back stress in V-groove solder lines." Now at Intel, Chandler, AZ.

M.Sc. students:

Wang Yang, 1995 Thesis title: "Ultra-fast soldering reaction of eutectic SnPb and eutectic SnBi on Pd surfaces." Now at Vitesse Semiconductor Corp., Camarillo, CA.

Ann A Liu, 1996 Thesis title: "Spalling of Cu-Sn compounds in the soldering reaction between eutectic SnPb and Au/Cu/Cr thin films." Now at TRW, Redondo Beach, CA.

Sharon S. Y. Huang, 1997 Thesis title: "Ultra-thin TaN as diffusion barrier for Cu interconnects." Now at Applied Materials, Santa Clara, CA.

Jessica P. Almaraz, 1998 Thesis title: "Morphology of the wetting reaction of Pb-free solder (eutectic SnAg and eutectic SnBi) on Ni substrates." Now at Northrop, Palmdale, CA.

Ben Zhengyi Jia, 1997 Thesis title: “Stress of Ni thin films on Si wafers,” Now a graduate student in Dept. EE, UCLA.

Yi-Pin Tsai, 1999 thesis title: “Microstructure and properties of low dielectric constant porous polymer PAE thin films,” Now at Intel, Los Angeles, CA.

Judy Pei-Yao Liu, 2000 Thesis title "Microstructure and property of Organically Modified Silicate Film Used for Interlayer Dielectric with Low dielectric Constant." Now at Applied Materials, Hsinchu, Taiwan, ROC.

Quyen Tang Huynh, 2000 Thesis title "Electromigration Study in PbSn Solder Lines." Now at Intel, Los Angeles, CA.

Gu Xu, 11/01, Thesis title "Effect of electromigration in V-shaped solder lines." Now at Dept. MSE, UCLA.

Cindy Wan-Ying Ma, 2002 Thesis title "The synthesis and characterization of porous low-k methylsilsesquioxane films for interlayer dielectric applications."

Jongsung Kim, 2002 Thesis title "Flow kinetics of molten Pb-free solders along V-groove etched on (001) Si surface." Now at UCLA.

Seung-Yub Lee, 2003 Thesis Title "Synthesis and Characterization of Organically Modified Silicates Thin Film for Low Dielectric Constant Materials." Now at Caltech.

Xi Zhang, 2004 Thesis Title, “Electroless Ni metallization of macro-porous silicon for the application to cross-talk isolation in mixed signal integrated circuits.” Now a Ph. D. candidate in Dept. of MSE, UCLA.

Minyu Yan, 2005 thesis on "The effect of immersion and evaporated Sn coating on the electromigration failure mechanism and lifetime of Cu damascene interconnects." Now a Ph. D. student in UCLA.

Mr. Rajat Agarwal, 2005 Thesis Title, "Electromigration in eutectic SnPb V-groove solder lines at 100 C." Now at Intel, Santa Clara, CA.

To see more detail information, please go to this webpage:
http://www.seas.ucla.edu/ms/faculty1/tu.html

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2007-05-19

越野之王--悍马(HUMMER)


一提起悍马(HUMMER),你立即会想到那一种具有越野之王称号的车辆,尤其是在伊拉克战争中及战争后,你总能从电视中看到美国大兵驾驶悍马军车巡逻于巴格达街头,或者被袭击后的现场。但在电视上看到的是军用悍马,你不可能买到,你出再高的价钱也只能买到民用版悍马。性能及外形最接近军用悍马的民用版悍马是H1型,这是一款真正的越野车,它在美国的基本售价为10.5万美元。如果你出不起这个价,可以买悍马H2型,这是一款现在正在中国流行的SUV,它的基本售价为48800美元(在亚运村市场曾标出150万元RMB,现在标价为118万RMB)。从今年夏天开始,悍马H2SUT也将开卖,它的价格至今还是个秘。SUT是什么?那是“运动型多功能卡车”的意思。在美国,卡车(Truck)一般是指我们中国人根本不正眼看的皮卡。在美国开皮卡就像是穿牛仔裤一样,不分贵贱和贫富,谁都可以开,而且从某种程度上讲,驾驶一辆皮卡比开轿车或SUV都更具“美国精神”。然而,悍马那高昂的价格把许多悍马迷拒之门外,它那宽大的车身也显得太霸道,它那“油老虎”式的大排量发动机也让不少人负担不起。



H3T——悍马小弟

哪里有需要,哪里就有产品。专为年轻人设计的小型悍马H3T概念车最近亮相,骤然间唤起了众多悍马车迷们的希望。H3T是一款单排皮卡车型,它虽是最小的悍马,长宽高仅为4443×1893×1795mm,但它继承了悍马H1的反叛造型特征,也拥有美国军车的DNA。H3T的两门两座式皮卡设计,是当今美国最为时尚的车身造型。

悍马H3T的外形就是皮卡,与它的三个哥哥H1、H2和H2 SUT都不同。它的顶篷可以电动打开,后窗也可以隐藏起来,从而形成一个完全开放的驾驶室。H3T的机盖仍像它的哥哥们一样是向前打开,而是是半自动的。它的通过性极强,配用34英寸的轮胎,离地间隙高达11.5英寸,从而使其接近角和离去角分别达到51度和50度。虽然你一眼就可看出H3T是悍马家族成员,但由于车身尺寸要小些,线条也稍柔顺些,因此比它的哥哥们看起来更亲切些,至少没有H1那么野蛮,也没有H2那样张扬。同时,较紧凑的车身尺寸也让H3T显得更具动感和灵敏。

H3T的轮胎和内饰设计是与世界运动服装名牌耐克合作的产物。耐克将它在运动鞋上的制作技术应用在
H3T轮胎上,使其不论在何种路面上都具有很强的抓地力;耐克在运动衣上的制作技术则运用在H3T的座
椅面料上,这种面料不仅轻质,而且不需机械手段即可达到温暖如春或清爽宜人的效果。


以往的悍马车都是在通用全尺寸卡车平台上开发的车型,而H3T则是在通用中型卡车平台上设计的车型。
它的四轮都靠近车身四角,采用四轮盘式刹车,前盘上设置了6活塞式卡钳,后盘则是4活塞式卡钳。



H3T配用通用的新型Vortec 3.5升直列五汽缸发动机,最大功率高达350马力,升功率达到100马力/升。

最大扭矩为474Nm。













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2007-05-14

A Brief Introduction of Fractal(分形几何学简介)


谁创立了分形几何学?
1973年,曼德勃罗(B.B.Mandelbrot)在法兰西学院讲课时,首次提出了分维和分形几何的设想。分形(Fractal)一词,是曼德勃罗创造出来的,其愿意具有不规则、支离破碎等意义,分形几何学是一门以非规则几何形态为研究对象的几何学。由于不规则现象在自然界是普遍存在的,因此分形几何又称为描述大自然的几何学。分形几何建立以后,很快就引起了许多学科的关注,这是由于它不仅在理论上,而且在实用上都具有重要价值。
分形几何与传统几何相比有什么特点:
⑴从整体上看,分形几何图形是处处不规则的。例如,海岸线和山川形状,从远距离观察,其形状是极不规则的。
⑵在不同尺度上,图形的规则性又是相同的。上述的海岸线和山川形状,从近距离观察,其局部形状又和整体形态相似,它们从整体到局部,都是自相似的。当然,也有一些分形几何图形,它们并不完全是自相似的。其中一些是用来描述一般随即现象的,还有一些是用来描述混沌和非线性系统的。


什么是分维?
在欧氏空间中,人们习惯把空间看成三维的,平面或球面看成二维,而把直线或曲线看成一维。也可以梢加推广,认为点是零维的,还可以引入高维空间,但通常人们习惯于整数的维数。分形理论把维数视为分数,这类维数是物理学家在研究混沌吸引子等理论时需要引入的重要概念。为了定量地描述客观事物的“非规则”程度,1919年,数学家从测度的角度引入了维数概念,将维数从整数扩大到分数,从而突破了一般拓扑集维数为整数的界限。

分维的概念我们可以从两方面建立起来:一方面,我们首先画一个线段、正方形和立方体,它们的边长都是1。将它们的边长二等分,此时,原图的线度缩小为原来的1/2,而将原图等分为若干个相似的图形。其线段、正方形、立方体分别被等分为2^1、2^2和2^3个相似的子图形,其中的指数1、2、3,正好等于与图形相应的经验维数。一般说来,如果某图形是由把原图缩小为1/a的相似的b个图形所组成,有:
a^D=b, D=logb/loga
的关系成立,则指数D称为相似性维数,D可以是整数,也可以是分数。另一方面,当我们画一根直线,如果我们用0维的点来量它,其结果为无穷大,因为直线中包含无穷多个点;如果我们用一块平面来量它,其结果是0,因为直线中不包含平面。那么,用怎样的尺度来量它才会得到有限值哪?看来只有用与其同维数的小线段来量它才会得到有限值,而这里直线的维数为1(大于0、小于2)。与此类似,如果我们画一个Koch曲线,其整体是一条无限长的线折叠而成,显然,用小直线段量,其结果是无穷大,而用平面量,其结果是0(此曲线中不包含平面),那么只有找一个与Koch曲线维数相同的尺子量它才会得到有限值,而这个维数显然大于1、小于2,那么只能是小数(即分数)了,所以存在分维。其实,Koch曲线的维数是1.2618……。

Fractal(分形)一词的由来
据曼德勃罗教授自己说,fractal一词是1975年夏天的一个寂静夜晚,他在冥思苦想之余偶翻他儿子的拉丁文字典时,突然想到的。此词源于拉丁文形容词fractus,对应的拉丁文动词是frangere(“破碎”、“产生无规碎片”)。此外与英文的fraction(“碎片”、“分数”)及fragment(“碎片”)具有相同的词根。在70年代中期以前,曼德勃罗一直使用英文fractional一词来表示他的分形思想。因此,取拉丁词之头,撷英文之尾的fractal,本意是不规则的、破碎的、分数的。曼德勃罗是想用此词来描述自然界中传统欧几里德几何学所不能描述的一大类复杂无规的几何对象。例如,弯弯曲曲的海岸线、起伏不平的山脉,粗糙不堪的断面,变幻无常的浮云,九曲回肠的河流,纵横交错的血管,令人眼花僚乱的满天繁星等。它们的特点是,极不规则或极不光滑。直观而粗略地说,这些对象都是分形。

分形的定义
曼德勃罗曾经为分形下过两个定义:
(1)满足下式条件
Dim(A)>dim(A)
的集合A,称为分形集。其中,Dim(A)为集合A的Hausdoff维数(或分维数),dim(A)为其拓扑维数。一般说来,Dim(A)不是整数,而是分数。

(2)部分与整体以某种形式相似的形,称为分形。
然而,经过理论和应用的检验,人们发现这两个定义很难包括分形如此丰富的内容。实际上,对于什么是分形,到目前为止还不能给出一个确切的定义,正如生物学中对“生命”也没有严格明确的定义一样,人们通常是列出生命体的一系列特性来加以说明。对分形的定义也可同样的处理。
(i)分形集都具有任意小尺度下的比例细节,或者说它具有精细的结构。
(ii)分形集不能用传统的几何语言来描述,它既不是满足某些条件的点的轨迹,也不是某些简单方程的解集。
(iii)分形集具有某种自相似形式,可能是近似的自相似或者统计的自相似。
(iv)一般,分形集的“分形维数”,严格大于它相应的拓扑维数。
(v)在大多数令人感兴趣的情形下,分形集由非常简单的方法定义,可能以变换的迭代产生。

转自:http://library.thinkquest.org/C006364/GB/fractal/intro.htm

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2007-05-08

Another notable figure in City Univerisity of Hongkong-Prof. Lee, Shuit-Tong(Hongkong)



Prof. Lee, Shuit-Tong
Member (Academican), Chinese Academy of Sciences

Professor (Chair) of Materials Science
Department of Physics & Materials Science

Director, Center Of Super-Diamond and Advanced Films (COSDAF)

BSc (CUHK), MS (Rochester), PhD (UBC)
Research Interest

Nanoscience and nanotechnology

Nanobiosensors

Nanooptoelectronics

Organic light emitting diode (OLED display technology

Nanodiamond

cBN and super-hard coatings

Surface science and modification



Awards

Hsun Lee Lecture Award, Institute of Metal Research, CAS, Shenyang, 2006

National Natural Science Award (2nd Class Award), State Council of the People's Republic of China, 2005

National Natural Science Award (2nd Class Award), State Council of the People's Republic of China, 2003

Croucher Senior Research Fellowship Award, Hong Kong, 2002

Humboldt Research Awards, Germany (from Alexander von Humboldt Foundation), 2001



Professional Roles

Editorship

Associate Editor, Applied Physics Letters (2006 - present)

Associate Editor, Diamond and Related Materials (1995 - present)

Regional Editor for Asia, Physica Status Solidi (2004 - present)

Editorial Board, Applied Physics Letters (2003 - 2005), Journal of Applied Physics (2003-2005), New Carbon Materials (1999 - present), Journal of Materials Science & Technology (2002 - 2005), Chinese Physical Society - Journal of Luminescence and Nanotechnolgy (2004 - present ) & Precision Engineering (2004 - present)

Advisory Editorial Board, Advanced Functional Materials (2000 - present) & Applied Nanoscience (2003 - present)

Guest Editor, Nanotechnology (Special issue, 2005)

Director, Key Laboratory of Nano-organic Optoelectronic Materials and Devices, TIPC, Chinese Academy of Sciences, Beijing, P.R. China (2001 - present)



Publications in Nature / Science

 


S. T. Lee, Y. Lifshitz, "The road to diamond wafers", Nature 424, 500 (2003).

D. D. D. Ma, C. S. Lee, F. C. K. Au, S. Y. Tong, S. T. Lee, "Small diameter silicon nanowire surface", Science 299,

1874-1877 (2003). The images of the paper were printed as the coverpage of the journal, Science (March 2003).

Y. Lifshitz, Th. Kohler, Th. Frauenheim, I. Guzmann, A. Hoffman, R. Q. Zhang, X. T. Zhou, S. T. Lee, "The mechanism of

diamond nucleation from energetic species", Science 297, 1531 (2002).

Y. Lifshitz, X. F. Duan, N. G. Shang, Q. Li, L. Wan, I. Bello, S. T. Lee, "Epitaxial diamond polytypes on silicon", Nature 412, 404 (2001).

S.T. Lee, H. Y. Peng, X. T. Zhou, N. Wang, C. S. Lee, I. Bello, and Y. Liftshitz, "A nucleation site and mechanism leading to epitaxial growth of diamond films", Science 287,104-106 (2000).

To see more detailed information about Prof. Lee Shuit-Tong, please go to this website:
http://www.cityu.edu.hk/cosdaf/Member%20Profiles/profilestlee.htm
Where you can find the lastest photo, and the members of his research group, as well as the condition about the Center Of Super-Diamond and Advanced Films(COSDAF).
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中文简介:
李述汤教授为材料化学及物理学家,是香港城市大学物理及材料科学系讲座教授。 1969年畢業於香港中文大學化學系,1971年在美國 Rochester 大學化學系獲碩士學位,1974年於加拿大 British Columbia 大學化學系獲博士學位。1969年毕业于香港中文大学化学系,1971年在美国 Rochester大学化学系获硕士学位,1974年于加拿大BritishColumbia大学化学系获博士学位。 1974年至1976在美國加州大學伯克力分校做博士後研究,1976年至1994年在美國Eastman Kodak公司任研究員,1994年到香港城市大學工作至今,現任香港城市大學超金剛石及先進薄膜研究中心主任,並兼任中國科學院理化技術研究所研究員和納米有機光電子實驗室主任。1974年至1976在美国加州大学伯克力分校做博士后研究,1976年至1994年在美国Eastman Kodak公司任研究员,1994年到香港城市大学工作至今,现任香港城市大学超金刚石及先进薄膜研究中心主任,并兼任中国科学院理化技术研究所研究员和纳米有机光电子实验室主任。

  李教授長期致力於光電子材料,如納米材料、金剛石和相關材料以及有機電致發光材料領域的研究。  李教授长期致力于光电子材料,如纳米材料、金刚石和相关材料以及有机电致发光材料领域的研究。 在《Science》、《Nature》等國際重要期刊發表論文550餘篇,獲美國專利15項,撰寫專著6部,論文被他人引用5000餘次。在《Science》、《Nature》等国际重要期刊发表论文550余篇,获美国专利15项,撰写专著6部,论文被他人引用5000余次。 2001至2005年相繼榮獲德國洪堡基金會研究成就獎 (Humboldt Research Award)、香港裘槎基金會高級研究成就獎(Croucher Senior Research Fellowship) 和2項中國國家自然科學二等獎 (State Natural Science Award, 2002 & 2005)。2001至2005年相继荣获德国洪堡基金会研究成就奖 (HumboldtResearchAward)、香港裘槎基金会高级研究成就奖(CroucherSeniorResearchFellowship) 和2项中国国家自然科学二等奖(StateNaturalScienceAward,2002&2005)。 目前擔任多種國際期刊的編輯及編委,包括《Applied Physics Letters》和《Diamond & Related Materials》的副總編輯、《Physica Status Solidi》國際雜誌亞太區主編。目前担任多种国际期刊的编辑及编委,包括《Applied PhysicsLetters》和《Diamond&RelatedMaterials》的副总编辑、《PhysicaStatusSolidi》国际杂志亚太区主编。 2005年12月榮膺為中國科學院院士。2005年12月荣膺为中国科学院院士。

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2007-05-07

Two Letters of Premier Wen









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The Working Principle of Plasma Sprayer ( 等离子喷涂设备的工作原理)

等离子喷涂技术是继火焰喷涂之后大力发展起来的一种新型多用途的精密喷涂方法.它包括大气等离子喷涂,保护气氛等离子喷涂,真空等离子喷涂和水稳等离子喷涂。 等离子体喷涂具有如下优点:①超高温特性,便于进行高熔点材料的喷涂。②喷射粒子的速度高,涂层致密,粘结强度高。③由于使用惰性气体作为工作气体,所以喷涂材料不易氧化。

其工作原理如下:

<1>等离子的形成(以N2为例):



0°k时,N2分子的两个原子程哑铃形,仅在x,y,z方向上平动;

大于10°k时,开始旋转运动;

大于10000°k时,原子间产生振动,分子与分子间碰撞,则分子会发生离解变为单原子:

N2+Ud——>N+N 其中 Ud为离解能

温度再升高,原子会发生电离: N+Ui——>N++e 其中 Ui为电离能

气体电离后,在空间不仅有原子,还有正离子和自由电子,这种状态就叫等离子体。

等离子体可分为三大类:①高温高压等离子体,电离度100%,温度可达几亿度,用于核聚变的研究;②低温低压等离子体,电离度不足1%,温度仅为50~250度;③高温低压等离子体,约有1%以上的气体被电离,具有几万度的温度。离子、自由电子、未电离的原子的动能接近于热平衡。热喷涂所利用的正是这类等离子体。

<2>喷涂原理:

等离子喷涂原理如图2所示。


等离子喷涂是利用等离子弧进行的,离子弧是压缩电弧,与自由电弧项比较,其弧柱细,电流密度大,气体电离度高,因此具有温度高,能量集中,弧稳定性好等特点。

按接电方法不同,等离子弧有三种形式:

①非转移弧:指在阴极和喷嘴之间所产生的等离子弧。这种情况正极接在喷嘴上,工件不带电,在阴极和喷嘴的内壁之间产生电弧,工作气体通过阴极和喷嘴之间的电弧而被加热,造成全部或部分电离,然后由喷嘴喷出形成等离子火焰(或叫等离子射流)。

等离子喷涂采用的就是这类等离子弧。

②转移弧:电弧离开喷枪转移到被加工零件上的等离子弧。这种情况喷嘴不接电源,工件接正极,电弧飞越喷枪的阴极和阳极(工件)之间,工作气体围绕着电弧送入,然后从喷嘴喷出。

等离子切割,等离子弧焊接,等离子弧冶炼使用的是这类等离子弧。

③联合弧:非转移弧引燃转移弧并加热金属粉末,转移弧加热工件使其表面产生熔池。这种情况喷嘴,工件均接在正极。

等离子喷焊采用这种等离子弧。

进行等离子喷涂时,首先在阴极和阳极(喷嘴)之间产生一直流电弧,该电弧把导入的工作气体加热电离成高温等离子体,并从喷嘴喷出,形成等离子焰,等离子焰的温度很高,其中心温度可达30000°k,喷嘴出口的温度可达

; 15000~20000°k。焰流速度在喷嘴出口处

可达1000~2000m/s,但迅衰减。粉末由送

粉气送入火焰中被熔化,并由焰流加速得到高于150m/s的速度,喷射到基体材料上形成膜。

图3等离子焰流温度分布


<3>等离子喷涂设备:等离子喷涂设备主要包括:

①喷枪:实际上是一个非转移弧等离子发生器,是最关键的部件,其上集中了整个系统的电,气,粉,水等。

②电源:用以供给喷枪直流电。通常为全波硅整流装置。

③送粉器:用来贮存喷涂粉末并按工艺要求向喷枪输送粉末的装置。

④热交换器:主要用以使喷枪获得有效的冷却,达到使喷嘴延寿的目的。

⑤供气系统:包括工作气和送粉气的供给系统。

⑥控制框:用于对水,电、气、粉的调节和控制。

<4>等离子喷涂工艺:

在等离子喷涂过程中,影响涂层质量的工艺参数很多,主要有:

①等离子气体:气体的选择原则主要根据是可用性和经济性,N2气便宜,且离子焰热焓高,传热快,利于粉末的加热和熔化,但对于易发生氮化反应的粉末或基体则不可采用。Ar气电离电位较低,等离子弧稳定且易于引燃,弧焰较短,适于小件或薄件的喷涂,此外Ar气还有很好的保护作用,但Ar气的热焓低,价格昂贵。

气体流量大小直接影响等离子焰流的热焓和流速,从而影响喷涂效率,涂层气孔率和结合力等。流量过高,则气体会从等离子射流中带走有用的热,并使喷涂粒子的速度升高,减少了喷涂粒子在等离子火焰中的“滞留”时间,导致粒子达不到变形所必要的半熔化或塑性状态,结果是涂层粘接强度、密度和硬度都较差,沉积速率也会显著降低;相反,则会使电弧电压值不适当,并大大降低喷射粒子的速度。极端情况下,会引起喷涂材料过热,造成喷涂材料过度熔化或汽化,引起熔融的粉末粒子在喷嘴或粉末喷口聚集,然后以较大球状沉积到涂层中,形成大的空穴。

②电弧的功率:

电弧功率太高,电弧温度升高,更多的气体将转变成为等离子体,在大功率、低工作气体流量的情况下,几乎全部工作气体都转变为活性等粒子流,等粒子火焰温度也很高,这可能使一些喷涂材料气化并引起涂层成分改变,喷涂材料的蒸汽在基体与涂层之间或涂层的叠层之间凝聚引起粘接不良。此外还可能使喷嘴和电极烧蚀。

而电弧功率太低,则得到部分离子气体和温度较低的等离子火焰,又会引起粒子加热不足,涂层的粘结强度,硬度和沉积效率较低。

③供粉

供粉速度必须与输入功率相适应,过大,会出现生粉(未熔化),导致喷涂效率降低;过低,粉末氧化严重,并造成基体过热。

送料位置也会影响涂层结构和喷涂效率,一般来说,粉末必须送至焰心才能使粉末获得最好的加热和最高的速度。

④喷涂距离和喷涂角

喷枪到工件的距离影响喷涂粒子和基体撞击时的速度和温度,涂层的特征和喷涂材料对喷涂距离很敏感。

喷涂距离过大,粉粒的温度和速度均将下降,结合力、气孔、喷涂效率都会明显下降;过小,会使基体温升过高,基体和涂层氧化,影响涂层的结合。在机体温升允许的情况下,喷距适当小些为好。

喷涂角:指的是焰流轴线与被喷涂工件表面之间的角度。该角小于45度时,由于“阴影效应”的影响,涂层结构会恶化形成空穴,导致涂层疏松。

⑤喷枪与工件的相对运动速度

喷枪的移动速度应保证涂层平坦,不出线喷涂脊背的痕迹。也就是说,每个行程的宽度之间应充分搭叠,在满足上述要求前提下,喷涂操作时,一般采用较高的喷枪移动速度,这样可防止产生局部热点和表面氧化。

⑥基体温度控制

较理想的喷涂工件是在喷涂前把工件预热到喷涂过程要达到的温度,然后在喷涂过程中对工件采用喷气冷却的措施,使其保持原来的温度。

近几年来,在等离子喷涂的基础上又发展了几种新的等离子喷涂技术,如:

1)真空等离子喷涂(又叫低压等离子喷涂)

真空等离子喷涂是在气氛可控的,4~40Kpa的密封室内进行喷涂的技术。

因为工作气体等离子化后,是在低压气氛中边膨胀体积边喷出的,所以喷流速度是超音速的,而且非常适合于对氧化高度敏感的材料。

2)水稳等离子喷涂

前面说的等离子喷涂的工作介质都是气体,而这种方法的工作介质不是气而是水,它是一种高功率或高速等离子喷涂的方法,其工作原理是:

喷枪内通入高压水流,并在枪筒内壁形成涡流,这时,在枪体后部的阴极和枪体前部的旋转阳极间产生直流电弧,使枪筒内壁表面的一部分蒸发、分解,变成等离子态,产生连续的等离子弧。由于旋转涡流水的聚束作用,其能量密度提高,燃烧稳定,因此,可喷涂高熔点材料,特别是氧化物陶瓷,喷涂效率非常高。

http://www2.zzu.edu.cn/classware/clkx/menu/biaomian/content/chap5/5-3.htm


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2007-05-06

Engineers Create 'Optical Cloaking' Design For Invisibility(excerpted from sciencetoday)

Science Daily — Researchers using nanotechnology have taken a step toward creating an "optical cloaking" device that could render objects invisible by guiding light around anything placed inside this "cloak."
The Purdue University engineers, following mathematical guidelines devised in 2006 by physicists in the United Kingdom, have created a theoretical design that uses an array of tiny needles radiating outward from a central spoke. The design, which resembles a round hairbrush, would bend light around the object being cloaked. Background objects would be visible but not the object surrounded by the cylindrical array of nano-needles, said Vladimir Shalaev, Purdue's Robert and Anne Burnett Professor of Electrical and Computer Engineering.

The design does, however, have a major limitation: It works only for any single wavelength, and not for the entire frequency range of the visible spectrum, Shalaev said.

"But this is a first design step toward creating an optical cloaking device that might work for all wavelengths of visible light," he said.

Research findings are detailed in a paper appearing this month in the journal Nature Photonics. The paper, which is appearing online this week, was co-authored by doctoral students Wenshan Cai and Uday K. Chettiar, research scientist Alexander V. Kildishev and Shalaev, all in Purdue's School of Electrical and Computer Engineering.

Calculations indicate the device would make an object invisible in a wavelength of 632.8 nanometers, which corresponds to the color red. The same design, however, could be used to create a cloak for any other single wavelength in the visible spectrum, Shalaev said.

"How to create a design that works for all colors of visible light at the same time will be a big technical challenge, but we believe it's possible," he said. "It is clearly doable. In principle, this cloak could be arbitrarily large, as large as a person or an aircraft."

The research is based at the Birck Nanotechnology Center at Purdue's Discovery Park.

Other researchers published findings in 2006 describing the mathematics generally required for the optical cloaking device. Those researchers include: John Pendry at the Imperial College in London, along with David Schurig and David R. Smith at Duke University, and simultaneously, Ulf Leonhardt at the University of St. Andrews in Scotland.

"These mathematical requirements were very general, and then we determined how to fulfill the requirements with a specific design," Shalaev said.

Leonhardt, a professor of theoretical physics, wrote a commentary piece about the Purdue paper appearing in the same issue of Nature Photonics. In the commentary, he compares the Purdue design to the Roman creation of "the first optical metamaterial," a type of glass containing nanometer-scale particles of gold. In ordinary daylight, a cup made of the glass appeared green, but then it glowed ruby when illuminated from the inside.

The Purdue research, Leonhardt writes, represents " ... theoretical simulations that show that a modified Roman cup based on modern nanofabrication technology will act as an invisibility device ... Any object you put inside will disappear as if dissolved in air, provided it is viewed through polarizing tinted glasses of precisely that colour."

Other researchers have developed concepts for cloaking objects smaller than the wavelengths of visible light and for objects detected in the microwave range of the spectrum, which are much larger than the wavelengths of visible light. But the new design is the first for cloaking an arbitrary object in the range of light visible to humans.

"What we propose is the cloaking of objects of any shape and size," Shalaev said.

Two requirements are needed to render an object invisible: Light must not reflect off of the object, and the light must bend around the object so that people would see only the background and not the cloaked object itself.

"If you satisfied only the first requirement of preventing light from reflecting off of the object, you would still see the dark shadowlike shape of the object, so you would know something was there," Shalaev said. "The most difficult requirement is to bend light around the cloaked object so that the background is visible but not the object being cloaked. The viewer would, in effect, be seeing around, or through, the object."

The device would be made of so-called "non-magnetic metamaterials." Meta in Greek means beyond, so the term metamaterial means to create something that doesn't exist in nature. Unlike designs for invisibility in the microwave range, the new design has no magnetic properties. Having no magnetic properties makes it much easier to cloak objects in the visible range but also causes a small amount of light to reflect off of the cloaked object.

"But this could, in principle, be offset by other means, for example, with antireflective coatings," Shalaev said. "The big challenge is how to make rays bend around the object, which we have described how to do in this paper."

A key factor in the design is the ability to reduce the "index of refraction" to less than 1. Refraction occurs as electromagnetic waves, including light, bend when passing from one material into another. Refraction causes the bent-stick-in-water effect, which occurs when a stick placed in a glass of water appears bent when viewed from the outside. Each material has its own refraction index, which describes how much light will bend in that particular material and defines how much the speed of light slows down while passing through a material.

Natural materials typically have refractive indices greater than 1. The new design reduces a refractive index to values gradually varying from zero at the inner surface of the cloak, to 1 at the outer surface of the cloak, which is required to guide light around the cloaked object.

Creating the tiny needles would require the same sort of equipment already used to fabricate nanotech devices. The needles in the theoretical design are about as wide as 10 nanometers, or billionths of a meter, and as long as hundreds of nanometers. They would be arranged in layers emanating from a central spoke in a cylindrical shape. A single nanometer is roughly the size of 20 hydrogen atoms strung together.

Although the design would work only for one frequency, it still might have applications, such as producing a cloaking system to make soldiers invisible to night-vision goggles.

"Because night-imaging systems detect only a specific wavelength, you could, in theory, design something that cloaks in that narrow band of light," Shalaev said.

Another possible application is to cloak objects from "laser designators" used by the military to illuminate a target, he said.

Leonhardt says in his commentary that creating a cloak for rendering total invisibility in the entire visible spectrum would require "further advances in optical metamaterials, new combinations of nanotechnology with highly abstract ideas ..."

The optical cloaking research is an indirect spinoff of research in Shalaev's lab that has been funded by the U.S. Army Research Office to develop metamaterials. In previous work, Shalaev's team created a metamaterial that has a "negative index of refraction" in the wavelength of light used for telecommunications, a step that could lead to better communications and imaging technologies. More recently, the researchers moved the wavelength for a negative refractive index material to the visible range.

Note: This story has been adapted from a news release issued by Purdue University.
To see more detail, please go to this website:
http://www.sciencedaily.com/releases/2007/04/070402141206.htm

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2007-05-05

An Introduction of Professor Paul K Chu(朱剑豪教授)(City University of Hong Kong)


Paul K Chu was born in Hong Kong and attended both primary and secondary school at St. Joseph's Anglo-Chinese School. He went to the United States at the age of 17 and was accepted to the honors program at The Ohio State University in Columbus, Ohio. He was awarded the prestigious American Chemical Society (ACS) Student Fellowship and worked at New England Aquarium in Boston on trace metal analysis of seawater during the summer of 1976. He received his BS in mathematics (cum laude and phi beta kappa) from Ohio State in 1977 and went to graduate school at Cornell University in Ithaca, New York. He won the DuPont teaching award as a teaching assistant at Cornell in 1978 and joined the research group of Prof. George H Morrison of the Department of Chemistry. Prof. Morrison was one of the prominent figures in analytical chemistry having been involved with the Apollo moon expedition programs. Prof. Morrison was a winner of the ACS Analytical Chemistry Award and Editor-in-Chief of Analytical Chemistry, the premier journal in analytical chemistry published by the American Chemical Society. Under the supervision of Prof. Morrison and Prof. James W Mayer of the Department of Materials Science & Engineering at Cornell, Paul conducted research on ion beam processing and characterization of semiconductors and received his MS and PhD in chemistry in 1979 and 1982, respectively.

Upon graduation, he joined Charles Evans & Associates in California which was a small company at that time but later became one of the biggest companies in the late 1980s in materials characterization. During the eight year span from 1982 to 1990, Paul was promoted 4 times and became one of the most recognized international figures in the area of secondary ion mass spectrometry (SIMS). He was one of the organizers of the SIMS-VII conference in Monterey, California in 1989, and wrote the chapter on SIMS in “Encyclopedia of Materials Characterization”. In 1990, with the help of the parent company, Paul started his first company, Evans Asia, in Hong Kong / Taiwan / Singapore / China specializing in materials characterization and analytical equipment.

In 1996, he joined City University of Hong Kong as a faculty member and ventured into the new area of plasma immersion ion implantation (PIII). He obtained financial support from City University of Hong Kong, University of Hong Kong, Hong Kong University of Science & Technology, as well as Hong Kong Research Grants Council (RGC) to establish the Plasma Laboratory in City University of Hong Kong. The Plasma Laboratory has emerged to be one of the most well known and versatile PIII facilities in the world, and Paul is recognized as one of the leading international figures in plasma-based materials engineering. He is the elected Chairman of the International Plasma-Based Ion Implantation Executive Committee which organizes the biannual International Workshop on Plasma-Based Ion Implantation and Deposition (PBII&D). He is also a member of the Ion Implantation Technology (IIT) International (Governing) Committee that organizes the biannual International Conference on Ion Implantation Technology.

Paul joined IEEE in 1997, became a senior member in 1999, and was elected Fellow of the Institute of Electrical and Electronics Engineers in 2003 for his contributions to the understanding of plasma immersion ion implantation and deposition. He is very active in the IEEE serving as a member of the international advisory board of the IEEE International Conference on Plasma Science (ICOPS) from 1996 to 1998, Guest Editor of 3 special issues of IEEE Transactions on Plasma Science [vol. 34, no. 4 (2006); vol. 33, no. 4 (2005); vol. 32, no. 2 (2004)], Senior Editor of IEEE Transactions on Plasma Science since 2006, and an executive committee (ExCom) member of the IEEE Plasma Science and Application Committee (PSAC) since 2007. Paul joined AVS (American Vacuum Society) in 2002 and was elected Fellow of AVS in 2006 for his contributions to plasma science and surface engineering of materials and industrial components. He is also Fellow of the Hong Kong Institution of Engineers (FHKIE). Paul is an elected scientific member of the Böhmishe Physical Society (BPS) as well as member of the American Chemical Society (ACS) and Materials Research Society (MRS). Locally, he is a technical advisor to the National 863 Materials & Surface Engineering R&D Center in Shenzhen, China, advisor to Shenzhen Polytechnic, and member of the standing committee of the Chinese Mechanical Engineering Society. He is an associate editor of International Journal of Plasma Science and Engineering and has been a member of the Editorial Board of Materials Science and Engineering: Reports since 2005, International Journal of Molecular Engineering since 2006, Surface and Interface Analysis since 2006, and Recent Patents on Material Science since 2007. He was a member of the Editorial Board of Nuclear Instruments and Methods in Physics Research B: Beam Interactions with Materials and Atoms from 2000 to 2006 and guest editor of the PBII&D2005 special issue published in Surface and Coatings Technology [vol. 201, no. 15 (2007)]. He was a co-chair / organizer of Symposium GG: Ion-Beam-Based Nanofabrication in the MRS Spring Meeting in San Francisco in 2007. He was a member of the Hong Kong Research Grants Council (RGC) Engineering Panel from 2000 to 2006.

Academically, in addition to being Professor (Chair) of Materials Engineering in the Department of Physics & Materials Science in City University of Hong Kong, he holds or has held advisory / visiting professorship in ten universities and research institutes in China: Institute of Microelectronics in Peking University (Beijing), Department of Materials Science in Fudan University (Shanghai), Department of Materials Science and Engineering in Shanghai Jiaotong University (Shanghai), Department of Materials Engineering in Southwest Jiaotong University (Chengdu), School of Materials Science and Engineering in Harbin Institute of Technology (Harbin), Department of Physics in Nanjing University (Nanjing), College of Materials Engineering in Jiamusi University (Jiamusi), Southwestern Institute of Physics (Chengdu), Shanghai Institute of Ceramics of The Chinese Academy of Sciences, and Shanghai Institute of Microsystem and Information Technology of The Chinese Academy of Sciences. He has established a joint PhD program with the University of Sydney in Australia in which students in his research group in City University of Hong Kong or School of Physics in the University of Sydney receive PhD degrees from both universities upon graduation. He also participates in a similar joint PhD program between City University of Hong Kong and Tsinghua University, China. Paul's teaching credentials are quite impressive. He won the DuPont Teaching Award at Cornell University. At City University of Hong Kong, he has been voted “best lecturer” and “best presenter” by students in his department and short listed for the Teaching Excellence Award. He has taught many short courses and professional seminars on materials characterization and processing in universities and companies in the US, Canada, China, Japan, Korea, Taiwan, and Singapore.

Paul's research activities are quite diverse, spanning plasma science and engineering, ion implantation, surface modification, functional thin films, biomaterials, semiconductor materials and processing, optoelectronic materials, as well as nanotechnology. He is the editor of two books on biomaterials and plasma engineering. He has published more than 10 book chapters, 550 papers in international refereed journals, and 550 international conference papers, many of which invited or plenary. His innovative works on light emission from plasma-implanted silicon, novel silicon-on-insulator (SOI) materials, as well as the enhancement of surface bioactivity and blood compatibility of biomaterials using plasma, chemical, and optical techniques have been featured many times in magazines and electronic journals. He has obtained US$10 million in research funding from agencies and companies in Hong Kong, Australia, China, Germany, Switzerland, and the US. Two of his research projects were awarded the "Excellent" rating by the City University of Hong Kong and Hong Kong Research Grants Council and he was the winner of the Second Best Paper Award in the IEEE International SOI Conference.

Paul is also heavily involved in applied research and industrial applications. His innovations on plasma processing and instrumentation have led to 8 United States patents and 3 Chinese patents. He founded his second company, Plasma Technology Ltd., in 1998 and co-founded his third company, Chengdu Pulsetech Electrical Co. Ltd., in 2001 to address the Chinese and other markets. The two companies specialize in the development of commercial plasma-based technologies as well as production of hardware such as ion sources, plasma implanters, and power supplies while also providing consultation to the industry. He was awarded the Applied Research Certificate of Merits for innovations in plasma instrumentation and power supplies and Hong Kong Awards for Industry: Technological Achievement Certificate of Merit for the development of plasma implantation and deposition technologies. Internationally, Paul’s achievement was instrumental to the establishment of Silicon Genesis Corporation in the Silicon Valley in California. Paul's research group produced the world’s first 100mm and 150mm silicon-on-insulator (SOI) wafers by plasma immersion ion implantation and ion-cutting, leading to multi-million dollar capital infusion from Intel, Applied Materials, MEMC, Komatsu, H&Q and other VCs into Silicon Genesis. The invention was featured on the cover of the 40th anniversary issue of Solid State Technology as the representative technology from Hong Kong.

Paul participates actively in amateur sports and is Honorary Manager of the City University of Hong Kong varsity badminton and swimming teams. He has won men's singles, men's doubles, mixed doubles, and teams events in CityU Student/Staff badminton tournaments. In swimming, he holds all of the City University of Hong Kong staff records in breast stroke and butterfly and has won more than 100 medals in Hong Kong masters swimming competitions.

For more information, please go to this website:
http://www.cityu.edu.hk/ap/plasma/Paul%20Chu/paul_chu.htm

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