Wednesday, May 30, 2007

JPD -- SPECIAL CLUSTER ON PLASMA-AIDED FABRICATION OF NANOSTRUCTURES AND NANOASSEMBLIES

Journal of Physics D Volume 40, Number 8, 21 April 2007

http://www.iop.org/EJ/toc/0022-3727/40/8

SPECIAL CLUSTER ON PLASMA-AIDED FABRICATION OF NANOSTRUCTURES AND NANOASSEMBLIES

EDITORIAL REVIEW
2223

IOP Physics
Reviews Plasma-aided nanofabrication: where is the cutting edge?
K Ostrikov and A B Murphy
Abstract References Citing articles Full text: Acrobat PDF (2.03 MB)

CLUSTER PAPERS
2242
Plasma nanofabrications and antireflection applications
J Shieh, C H Lin and M C Yang
Abstract References Citing articles Full text: Acrobat PDF (1.12 MB)

2247
A plasma process for the synthesis of cubic-shaped silicon nanocrystals for nanoelectronic devices
Ameya Bapat, Marco Gatti, Yong-Ping Ding, Stephen A Campbell and Uwe Kortshagen
Abstract References Citing articles Full text: Acrobat PDF (890 KB)

2258
Synthesis of silicon nanocrystals in silane plasmas for nanoelectronics and large area electronic devices
P Roca i Cabarrocas, Th Nguyen-Tran, Y Djeridane, A Abramov, E Johnson and G Patriarche
Abstract References Citing articles Full text: Acrobat PDF (1.21 MB)

2267
Transport of nano-particles in capacitively coupled rf discharges without and with amplitude modulation of discharge voltage
Kazunori Koga, Shinya Iwashita and Masaharu Shiratani
Abstract References Citing articles Full text: Acrobat PDF (781 KB)

2272

IOP Physics
Reviews Metal plasmas for the fabrication of nanostructures
André Anders
Abstract References Citing articles Full text: Acrobat PDF (1.62 MB)

2285

IOP Physics
Reviews Factors determining properties of multi-walled carbon nanotubes/fibres deposited by PECVD
M S Bell, K B K Teo and W I Milne
Abstract References Citing articles Full text: Acrobat PDF (1.51 MB)

2293
Structure and properties of zirconia (ZrO2) films fabricated by plasma-assisted cathodic arc deposition
Weifeng Li, Xuanyong Liu, Anping Huang and Paul K Chu
Abstract References Citing articles Full text: Acrobat PDF (1.52 MB)

2300
Behaviour of oxygen atoms near the surface of nanostructured Nb2O5
U Cvelbar and M Mozetic
Abstract References Citing articles Full text: Acrobat PDF (367 KB)

2304
Chemically active plasmas for deterministic assembly of nanocrystalline SiC film
Q J Cheng, J D Long, Z Chen and S Xu
Abstract References Citing articles Full text: Acrobat PDF (640 KB)

2308
Nanostructures of various dimensionalities from plasma and neutral fluxes
I Levchenko and K Ostrikov
Abstract References Citing articles Full text: Acrobat PDF (1.43 MB)

2320

IOP Physics
Reviews New type of BN nanoparticles and films prepared by synergetic deposition processes using laser and plasma: the nanostructures, properties and growth mechanisms
Shojiro Komatsu
Abstract References Citing articles Full text: Acrobat PDF (5.63 MB)

2341
Plasma assisted production of chemical nano-patterns by nano-sphere lithography: application to bio-interfaces
Andrea Valsesia, Tarik Meziani, Frédéric Bretagnol, Pascal Colpo, Giacomo Ceccone and François Rossi
Abstract References Citing articles Full text: Acrobat PDF (1.57 MB)

2348
Control of particle size and phase formation of TiO2 nanoparticles synthesized in RF induction plasma
J-G Li, M Ikeda, R Ye, Y Moriyoshi and T Ishigaki
Abstract References Citing articles Full text: Acrobat PDF (1.26 MB)

2354
Thermal plasma synthesis of nanostructured silicon carbide films
Steven L Girshick and Jami Hafiz
Abstract References Full text: Acrobat PDF (1.57 MB)

2361

IOP Physics
Reviews Carbon nanostructures production by gas-phase plasma processes at atmospheric pressure
J Gonzalez-Aguilar, M Moreno and L Fulcheri
Abstract References Citing articles Full text: Acrobat PDF (2.19 MB)

2375
Large-scale production of single-walled carbon nanotubes by induction thermal plasma
Keun Su Kim, German Cota-Sanchez, Christopher T Kingston, Matej Imris, Benoit Simard and Gervais Soucy
Abstract References Citing articles Full text: Acrobat PDF (2.16 MB)

2388
Factors affecting synthesis of single wall carbon nanotubes in arc discharge
Michael Keidar
Abstract References Citing articles Full text: Acrobat PDF (202 KB)

2394
Suspension and solution plasma spraying of finely structured layers: potential application to SOFCs
P Fauchais, R Etchart-Salas, C Delbos, M Tognonvi, V Rat, J F Coudert and T Chartier
Abstract References Citing articles Full text: Acrobat PDF (3.66 MB)

2407
Growth mechanism of silicon-based functional nanoparticles fabricated by inductively coupled thermal plasmas
M Shigeta and T Watanabe
Abstract References Citing articles Full text: Acrobat PDF (1.71 MB)

TOPICAL REVIEW
R121

IOP Physics
Reviews Complex plasma: dusts in plasma
Osamu Ishihara
Abstract References Full text: Acrobat PDF (1.24 MB)


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Wednesday, May 23, 2007

Book: 《等离子体放电原理与材料处理》兼等离子体材料处理教材之面面观



最近从当当网上邮购了几本书,其中一本是UC Berkeley 教授Michael A.Lieberman and Allan J.Lichtenberg专著《Principles of Plasma Discharges and Materials Proce 》的中译本《等离子体放电原理与材料处理》清华蒲以康教授译(07年出版)。虽然曾有英文第一版电子版,但是出现中文版的时候还是毫不犹豫的买了一本。自己对此书的评价很简单:自己眼中本专业方向研究生在学期间最值得必读精读的两本书之一(另一本是阿杜的《电子薄膜科学》),可惜知之甚晚,不过希望现在亡羊补牢,犹时未晚。

【内容提要】本书全面深入地介绍等离子体物理和化学的基本原理,以及工业等离子体材料处理的原理,并应用基本理论分析各种常见等离子体源的放电状态。书中还介绍半导体材料的刻蚀、薄膜沉积,离子注入等低温等离子体在材料处理方面的应用,反映本领域的最新研究进展。全书共18章,内容包括等离子体的基础知识、等离子体放电过程中的粒子平衡和能量平衡、容性和感性放电、波加热的气体放电、直流放电、刻蚀、沉积与注入、尘埃等离子体,以及气体放电的动理论等。本书可供等离子体物理领域的研究生、技术人员,以及微纳电子领域的科技研发人员参考学习。
【作者简介】迈克尔·A·力伯曼,博士,加利福尼亚大学伯克利分校电子工程研究生院教授,曾发表170多篇有关等离子体、等离子体材料处理和非线性动力学方面的研究论文,而且同里登伯格教授合著有RegularandStochasticMotion和RegularandChaoticDynamics(第二版)。
摘录:等离子体材料处理教材之面面观
摘自:http://www.chinaecnet.com/ele/el063961.asp

本文摘自《电子工业专用设备》
黄梦琦,蒲以康 (清华大学工程物理系 北京 100084)
......
5 对现有书籍的比较

根据上文对不同的教材提出的理想要求,下面将对市场上销售的主要离子体相关书籍进行分析比较,进而了解当前等离子体材料处理方面教材的现状。

5.1 中文书籍

(1)《低温等离子体化学及其应用》

主要内容:从化学科学的角度对低温等离子体的基本概念、等离子体的诊断方法、等离子体化学反应的机理、基本反应过程、动力学模型的建立方法、等离子体聚合反应、等离子体引发聚合反应、等离子体表面处理的基础规律及其应用、氧等离子体化学及应用、已实用化的等离子体CVD技术作了系统的论述和介绍,并提供了涉及多个领域的应用信息[9]。

适合对象:本书完全从化学的立场来解释等离子体化学反应,强调的是等离子体化学技术在高分子聚合物材料方面的应用,而对等离子体化学技术在电子工业中的应用基本负责没有介绍,因此本书比较适合那些对分子聚合物材料加工和应用感兴趣的读者阅读,而对于我们选择教材来说,这本书中详细介绍的等离子体聚合化学并不是刻蚀化学,对微电子制造技术和薄膜沉积技术的指导意义不大,因此对于培养专家级研发人和技术人员来说,这本书都不合适。

(2)《等离子体化学与工艺》

主要内容:本书基础部分介绍了等离子体的性质、特点、化学反应规律及等离子体的发生方法和反应装置原理,应用部分介绍了等离子体在化学合成、薄膜制备、高分子聚合、高分子材料表面处理及半导体器件工艺领域的应用[10]。

适合对象:这本书关于实际应用部分的介绍重要放在了等离子体聚合化学方面的应用,虽然有涉及到溅射制膜的知识,但该过程只是物理过程,而并没有谈到刻蚀化学,对等离子体化学在电子工业上应用的介绍也很少,这主要是受到了国内研究趋势的影响,即国内对等离子体刻蚀技术的研究基础非常薄弱,过去的研究大部分仅限于等离子体聚合化学方面,涉及刻蚀化学的非常少,因此本书也不合适作为培养专家级研发人才和普通技术人员的教材。
(3)《等离子体加工技术》

主要内容:本书介绍了离子体加工技术原理及其应用,包括等离子体基本性质、等离子体的形成、等离子体诊断、等离子体加工技术中的物理化学问题,并重点介绍了化学气相沉积(VCD)、物理气相沉积(PVD)、刻蚀的等离子体设计及其应用[11]。

适合对象:虽然这本书比前两本书所覆盖知识面更广,但本书仅也只有8章159页,因此对原理和应用大多只能是简单介绍,而不可能在等离子体加工技术方面有深入分析。另外,本书出版于1990年,因此书中介绍的理论和应用都是20世纪80年代的内容,引用的文献更是古老,大多是1979、1980年的文献,当时对等离子体理论的研究还刚起步,实验和实际生产方面也很落后,而最近一段时间,等离子体刻蚀技术取得了突飞猛进的发展,以前的旧的理论早已和现在的实际生产脱节,无法指导现代化的生产,因此本书也不适合作为培养专家级研发人和普通技术人员的教材。

(4)《低温等离子体物理基础》

主要内容:本书系统地阐述了低温等离子体物理学的基础理论,包括低温等离子体的概述及基本性质,低温等离子体微观和宏观的理论描述,等离子体的产生诊断,电弧等离子体和高频等离子体物理,其中对低温等离子体的基本规律、粒子碰撞理论及存在电磁场时稠密低温等离子体的流动理论进行了深入的分析,最后简要揭示了等离子体的技术应用[12]。

适合对象:本书虽然题目是关于低温等离子体的,但内容中重点介绍的却是热等离子体(由电弧放电产生,接近热平衡的等离子体)理论、分析、描述的过程都是关于热等离子体的,而集成电路制造过程中用到的等离子体却是低温等离子体(由辉光放电产生,非热平衡的等等离子体)另外,本书出版于1983年,同样编写年代也太早,对于最新的研究成果多没有介绍,总结以上两个原因,本书并不适合作为培养等离子体材料处理方面人才的教材。

(5)《等离子体电子工程学》

主要内容:先从微观角度出发,了解等离子体中单个粒子的运动规律以及粒子间的碰撞过程,然后从控制角度把等离子体看作一个整体,考察其总体的平均行为特性,接着介绍从气体放电到等离子体诞生的发展过程,最重要的一部分是介绍生成等离子体的各种方法;用质量放电来生产低温等离子体的方法和用高频放电和微波放电法生产等离子体的方法,因为应用等离子体技术的一个重要方面是根据不同用途选择最合适的等离子体生成方法,最后介绍了等离子体在尖端电子制造和环境改善技术中的应用[13]。

适合对象:因为本书的编写目的是作为教授大学生等离子体课程的教科书,因此内容并不十分深奥,语言非常易懂。并且本书对等离子体在集成电路制造工艺中的应用介绍较浅显,只是对等离子体刻蚀方法作了一般性的描述,所以适合对等离子体相关知识刚入门的读者作为一本科普读物来阅读,以掌握等离子体的一些基本特性和生成方法,并不适合作为培养等离子体材料处理方面人才的教材。

(6)《等离子体物理学导论》 主要内容:本书作者是实验等离子体物理学方面的出色科学家。本书涉及等离子体流体方程、扩散和电阻率、分布函数和动力方程、等离子体中各类不稳定性和朗道阻尼等内容,本书对等离子体物理的相关概念,公式和原理作了详细的解析和论证,而对具体的等离子体技术应用的内容基本上没有涉及,因此这是一本纯粹教授等离子体物理理论的教科书[14]。

适合对象:因为本书是从加州大学洛杉矶分校的等离子体物理大学课程的讲课笔记发展而成,因此从难易程度来说非常合适作为学习和研究等离子体物理学知识的入门教材,但本书介绍的主要内容是关于等离子体受控核聚变的,并没有介绍低温等离子体的碰撞,激发现象及其材料的作用原理,因此并不适合那些学习低温等离子体物理的读者,另外由于本书编写的年代较早,(1981年),因此从内容和编写年代来说,本书都不适合作为培养低温等离子体材料处理方面人才的教材。

5.2 英文书籍

(1) Handbook of Advanced Plasma Proce ing Techniques

主要内容:本书介绍了等离子体物理基本概念,等离子体和材料处理模型,等离子体诊断,等离子体诱发的损伤和各种应用,如光掩模、微电子机械技术、半导体刻蚀、高密度等离子体沉积和磁性材料刻蚀等。本书介绍的重点放在材料处理的实际应用,对于各种刻蚀技术和刻蚀材料都做了详细介绍[15]。

适合对象:本书英文书籍是专门针对等离子体材料处理技术的一本技术手册,内容覆盖等离子体刻蚀技术的各个方面,如设备的使用方法,装配方法、设备的特点、刻蚀速率等参数如何调整等等,因此对于我们急需培养的等离子体材料处理方面的技术人员来说,这本书是一本全面专业的实用手册,但对于专业人员来说,这本书对于等离子体物理化学内容的介绍可能较少,因此不能完全满足这些读者对于基础理论的学习需要,必须结合另外的专门介绍等离子体物理化学基础理论的书籍一起学习。

(2) Principles of Plasma Discharges and Materials Proce ing

主要内容:全书共18章,依次介绍了等离子体的基本方程和平衡态性质、原子碰撞、等离子体动力学、扩散和输运、直流鞘层、化学反应和平衡、分子碰撞、化学动力学与表面过程、放电过程中的粒子平衡和能量平衡、容性放电、感性放电、波加热的气体放电、直流放电、刻蚀、沉积与注入、尘埃等离子体、气体放电的动力学理论,该书作者凭借积累多年的研究经验,在书中全面具体的介绍了近一二十年的等离子体材料处理技术和设备的发展过程,既有理论介绍,又有实际应用的部分,可以说是一本系统的等离子体材料处理方面的百科全书[16]。

适合对象:本书从物理原理上对各种放电模式的物理模型、刻蚀跟等离子体物理之间的关系进行分析,重点介绍如何将理论知识和实际技术和设备联系起来,这正是专业人才应该掌握的知识。该书内容全面,介绍由浅入深,非常适合作为教材使用,对于培养等离子体材料处理方面的各种不同人才来说都是一个很好的选择。

6 结果与讨论

总结以上分析比较的这些书籍,可以发现国内现有书籍的内容要么侧重等离子体聚合化学及应用,要么侧重等离子体受控核聚变的介绍,并且书籍发行的年代都十分古老,中文相关书籍缺少的是专门介绍低温等离子体材料处理处理方面的书籍,特别缺少那些介绍如何将等离子体基础知识和实际应用中等离子体离子体刻蚀工艺和刻蚀设备相结合的书籍,教材市场的这种现状是肯定不能满足国内对等离子体材料处理方面的教材的需要,而国外在这方面做的较好,不少介绍这方面先进技术的权威书籍都值得我们学习借鉴。因此读者在选择合适的等离子体材料处理方面的教材的时候,可以适当偏重英文教材。

要想改变我国等离子体材料处理方面教材市场的这种现状,我们应该以国外的优秀书籍为编写目标,努力编写出符合中国国情的等离子体材料处理方面的教材,另外,直接阅读英文书籍对于实际教学来说还是有困难的,因此我们也需要更多优秀的英文书籍的中译版。

最后,除了编写教材之外,还是很多其他的措施也能够促进我国等离子体刻蚀技术的发展,例如:建议教材编写者更多的进行实践;鼓励技术人员和研发人员参加企业举办的短训班或者实习,建立国家级研发中心,加大人才引进力度等。
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Monday, May 21, 2007

MRS Bulletin 0703: Advanced Inorganic Materials for Photovoltaics


Excerpted from:
http://www.mrs.org/s_mrs/sec_subscribe.asp?CID=8656&DID=193233

Advanced Inorganic Materials for Photovoltaics
Volume 32, No. 3
BUY THIS ISSUE

Guest Editors: Abdelilah Slaoui and Reuben T. Collins

By 2050, world annual energy consumption is predicted to grow from the present 13 terawatt-years (TWyr) to near 30 TWyr. Although all energy sources must be considered in meeting this challenge, sunlight is a plentiful source able to supply a significant amount of energy cleanly (without CO2 emission), if it can be captured efficiently and cost-effectively using photovoltaic materials. This issue of MRS Bulletin reviews the status and future development of solar photovoltaic technologies based on inorganic materials, covering cadmium telluride, amorphous silicon, quantum dots, multijunction solar cells, transparent conductors, and other innovations. We invite you to view the introductory article for this issue, "Advanced Inorganic Materials for Photovoltaics" by Abdelilah Slaoui and Reuben T. Collins, Guest Editors.

Article - Amorphous Silicon, Microcrystalline Silicon, and Thin-Film Polycrystalline Silicon Solar Cells
Ruud E.I. Schropp, Reinhard Carius, and Guy Beaucarne

Theme Article - Materials Challenges for CdTe and CuInSe2 Photovoltaics
Joseph D. Beach and Brian E. McCandless

Theme Article - High-Efficiency Multijunction Solar Cells
Frank Dimroth and Sarah Kurtz

Theme Article - Solar Cells Based on Quantum Dots: Multiple Exciton Generation and Intermediate Bands
Antonio Luque, Antonio Martí, and Arthur J. Nozik

Theme Article - Transparent Conducting Oxides for Photovoltaics
Elvira Fortunato, David Ginley, Hideo Hosono, and David C. Paine

Abstract
Transparent conducting oxides (TCOs) are an increasingly important component of photovoltaic (PV) devices, where they act as electrode elements, structural templates, and diffusion barriers, and their work function controls the open-circuit device voltage. They are employed in applications that range from crystalline-Si heterojunction with intrinsic thin layer (HIT) cells to organic PV polymer solar cells. The desirable characteristics of TCO materials that are common to all PV technologies are similar to the requirements for TCOs for flat-panel display applications and include high optical transmissivity across a wide spectrum and low resistivity. Additionally, TCOs for terrestrial PV applications must use low-cost materials, and some may require device-technology-specific properties. We review the fundamentals of TCOs and the matrix of TCO properties and processing as they apply to current and future PV technologies.

Technical Feature - Reconstruction of Historical Alloys for Pipe Organs Brings True Baroque Music Back to Life
Brigitte Baretzky, Milan Friesel, and Boris Straumal

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Friday, May 18, 2007

转载 何毓琦:一个大学教授在美国的生活

转载一篇很不错的文章,此外作者也开了个blog:
http://www.sciencenet.cn/blog/何毓琦.htm

Excerpted from:
http://www.sciencenet.cn/htmlnews/2007511193241937179076.html

一流大学研究晋级两大黄金法则:成名要趁早 报告要做好

哈佛大学终身教授、美国工程院院士、中国科学院及中国工程院外籍院士何毓琦博士长期从事系统控制科学及工程应用研究,在最优控制、微分对策、团队论、离散事件动态系统和智能系统等方面做出了重大贡献。是动态系统现代控制理论的创导者之一。何毓琦博士长期致力于祖国大陆的科研发展,不但培养了多名中国学生,更在2001年受聘清华讲座教授。何毓琦博士以敢于针砭时弊闻名科学界,2007年4月25日入驻科学网博客以来,受到网民的热烈欢迎。现根据部分网民的要求,全文翻译《一个大学教授在美国的生活》(Life of an Academic in the US)一文,希望对中国读者有所帮助。


除了在工业界全职工作了三年,我的整个学术生涯都是在美国渡过的。尽管我一直只供职于一所大学,我在伯克利、得克萨斯大学奥斯丁分校、伦敦帝国学院做过整学期的访问学者,而且还对全世界无数学校和研究机构进行过短期访问。因此,将我40余年的经历与科学网的中国读者分享大概是一件有意义的事情。此外,在适当的时候,我愿意将这些在美国的经历与中国的情况相对照。当然了,美国大学的种类很多,我将主要讨论研究型大学。一些非常优秀的纯教学院校则不在我的讨论范围之内,如马萨诸塞州威廉姆镇的威廉姆斯学院(Williams College)和宾夕法尼亚州费城的斯沃特穆尔学院(Swarthmore College)。最后,下面写的都是我的个人经历,请不要当作典型或者真理。

在一流大学晋升主要通过两种途径。第一,成为一名伟大的教师(仅仅优秀是不够的)。也就是说,你能够在教授常见本科课程,比如基础经济学、基础物理、计算机入门等课程的时候发挥创造性和组织能力。这说起来容易,做起来难。因为从学术水平上讲,一个系里能够教这种课的老师很多,你必须表现出超常的教学和创造力。另外,学校里选课人数众多的本科课程其实很少。我在哈佛待了40多年,经常看到非常优秀甚至近乎伟大的老师没有拿到终身职位,不得不离开哈佛。(注:美国大学盛行一种制度,即所谓的“七年试用期”,在这七年里,你要么拿到终身职位,要么走人。不遵守这“七年试用期”的学校会被列入美国大学教授联合会的黑名单。)

另外一个晋级的途径当然就是搞研究了。教学基本上只是一个本地行为,而研究则是世界性的。对学校来说,一流的研究工作的性能价格比比教学要高的多,因此学校更看重研究。然而在一流大学里,你的竞争对手是全世界的研究人员。比如在哈佛,在决定你是否能够拿到终身教职的时候,学校会特意把你与世界上同领域的权威放在一起比较。

我是在1965年拿到哈佛的终身教授职位的,那之后的30年里,我们系没有授予任何一位系统科学领域的年轻教授终身职位。尽管哈佛校长和各系主任绝对不敢承认,我早早就意识到而且不断地教导年轻同事们:“哈佛付你钱是为了让你维护并不断提高它的世界声誉的,别的都是次要的。” 因此黄金法则一:尽早建立你的国际学术声誉

为了搞研究,你必须有经费、有学生。实际上,如果没有经费,你根本不可能供得起学生。在美国,尽管有各类奖学金,大多数研究生还都依靠导师的科研经费支持着。一般一个研究生一年要花掉导师五万美元。如果你的组里一直保持五到六个研究生的话,你每年最低必须保证25万美元左右的预算,而你必须和全美国的同领域科学家们竞争来争取这些经费。你不用指望研究生的头两年能有什么回报,博士生只有到了第三年第四年才开始出成绩,所以导师在录取研究生的时候是做出了很大投资的。我认识不少同事,跟我发誓赌咒再也不招中国学生了,因为他们来一两年就跑掉了,要么转去一个更好的学校,要么有了别的什么机会。不错,美国是一个自由的国家,从法律角度看,学生没有义务必须读完博士,但是从道德角度讲,导师在你身上花了那么多钱,你应该肩负起你的责任。然而,并不是所有中国学生都意识到这一点,这种行为对于后来想来美国读书的中国学生来说等于是过河拆桥。

还有,一个一线大学教授至少要花25%的工作时间在编写基金申请书、准备研究报告和撰写论文上。因此黄金法则二:擅长写作和演讲,了解什么是最前沿的课题,也就是所谓的“时势造英雄”。(当然了,如果你能开创一个崭新的研究领域,而且能够说服全世界这就是最前沿的,那就更棒了,所谓“英雄造时事”。)

黄金法则一和黄金法则二意味着你必须让全世界知道你是谁。怎么才能做到这一点呢?在优秀的学术期刊上发表文章,在学术会议上好好介绍你的研究。很多科学家以为搞科研是最最重要的,相比之下,写论文和做报告不那么重要。但是实际上,除非你提出了相对论或者搞定了人类基因图谱,你的研究要跟成千上万和你一样聪明的人竞争。实际上,我个人认为,有个好想法,写篇好文章和给个好报告是三项独立的而且同等重要的工作。每一项工作要付出的艰苦努力都是完全不同的。要想做个好报告,仅仅从论文里复制拷贝制作一套PPT是远远不够的,对着论文照本宣科也是远远不够的。我们经常看到一些本来才华横溢的科学家做的报告惨不忍睹,令人不忍卒听。实际上,一个好的报告应该能够让一般听众听懂,同时又给专家同行留下非常深刻的印象。统计数据表明,一篇普通的发表了的科技论文的读者只有5位,其中还包括了论文的编辑和审稿人。但是,一次优秀的讲座的听众可能多达数十人、数百人甚至数千人。大多数听众一个月后大概都不记得你讲座的具体内容了,但是多年以后他们可能还会记得,你的那次讲座非常成功。这种针对听众的讲座能给你带来许多意想不到的好处。目前,各种政府基金管理机构的官员参加大大小小的会议,主要就是为了了解最热门的研究领域,发现那些值得资助的人。你给报告的时候他们很可能就坐在听众中间。那么,让你的报告清晰易懂的重要性就显而易见了。然而,我还是不断地碰到很多研究出色的科学家在做报告的时候完全无视听众的存在,报告晦涩难懂,让人觉得他非常傲慢无礼。我年轻的时候,如果听不懂别人的报告,就怪自己无知;现在,如果我听不懂一个人在说些什么,我就怪那个作报告的人。让报告清楚明白、不浪费我的时间是他的责任。我的座右铭是“完全可以让任何人在任何特定时间内适当地明白任何事情。”

多年以来,投身学术研究意味着接受一种较为贫穷的生活方式,因为学校的工资低于工商业界,但是至少在科学技术领域,情况已经大为改观。为工业界做咨询可以大大增加你的收入,但是做咨询的真正好处在于你处理的是一些实际问题,你经常会受到这些实际问题的启发,转向新的研究方向。而且你取得任何一点成绩都会有一支“拉拉队”自动为你欢呼加油。你根本不需要付出额外的努力,说服别人你的工作很重要。你也不会钻牛角尖,在一些没人感兴趣的问题上浪费时间。几乎所有的美国大学都意识到咨询的这一好处,允许教授每周一天时间用于咨询工作。就我而言,我在整个学术生涯中都不断地从事咨询工作,而且我敢说我所有绝妙的研究想法都来源于某项咨询工作,尽管一开始的时候,我对这项咨询项目所知甚少。合适的咨询工作会创造“三赢”的局面:客户赢、学校赢、你也赢。

投身科研的另外一个次要好处是你可以借参加国际会议的机会周游五湖四海。商业界的人出差,时间都很紧,基本上来去匆匆,没什么休闲的机会。但是研究人员出差,会前会后都能找出观光的时间来(比方说王鸿飞博士的博客里写到的)。比起旅行的全部费用,你自费的部分是很少的。有本旅游手册叫做《有生之年必去的1000个地方》,我在40余年的学术生涯里,已经和我太太去了这1000个地方中的230个,还不算很多这本书没有列出来的地方。中国有句古话叫做“走千里路胜读万卷书。”旅行能够让你增长见识,而且在学术界你会和很多第一次见面的国际同行交上朋友,因为你们的研究兴趣相投,所以能够一见如故。他们是你最好的导游。(注:有一次,我让我的一个中国研究生招待一位南美同行,她回来以后非常兴奋,告诉我说这个陌生人竟然能够理解她的博士论文研究中的种种精妙之处,尽管他们来自两个隔着千山万水的不同国家,年龄相差很多而且以前从未谋面。)

至于研究的乐趣嘛,当你在数个月的艰苦工作后第一次有了不错的发现,你会陷入几秒钟的狂喜——全世界你是唯一一个认识这个真理的人。这样的感觉只可意会不可言传。你坐立不安,来回踱步,彻夜难眠,有时候甚至会高兴到胃疼的地步。我没有在商业界待过,不能百分之百肯定,但是我想这种发现的喜悦大概不亚于赢得一个大订单或者在股市大有斩获。要是我一年能享受一次这样的喜悦,我就很满足了。一个人回顾他的学术生涯,审查他一生撰写发表的所有文章,也许只有10%能够经受时间的考验。这和旅行很相似。你很高兴去过很多地方,但是只有几个地方让你终身难忘。

最好的一点是,搞研究的人时间比较自由,基本上你可以自行安排。你是你自己的老板。和普通商业界人士比起来,除了申请经费,你不得不做的无聊重复的工作要少很多。你可以在你真心喜欢的工作上投入差不多50%的时间和精力。我一直告诫我的学生,如果你50%的时间喜欢你正在做的工作,那么这就是一个非常棒的工作!因为你喜欢你的工作,所以你会格外刻苦。节假日和平时没有区别。一天工作20个小时、一周工作100个小时更是家常便饭。我已经这把年纪了,而且正式退休了,每天醒着的一半以上的时间还花在学术上。

通过在中国的所见所闻,还有我在科学网博客上读到的,我发现中国的学术生活正在变得越来越国际化,和世界其它地方越来越像了。我期待着将来与科学网和其它地方的同行们更多地交换意见。(科学网 何姣译)


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<大面积玻璃镀膜> (德)格雷瑟



本书为大面积玻璃镀膜技术领域专著。介绍了利用薄膜技术对平板玻璃进行重新定义深加工的可能性与商机。玻璃薄膜可以分成两大方问:真空条件下的物理工艺和大气条件下的化学工艺。各种玻璃镀膜产品有着广泛的应用。本书对其历史现状及其发展前景作了详尽的论述及预测,也对各种镀膜技术的优缺点进行了比较。更为难能可贵的是,作者把近年来镀膜的最新技术也做了介绍。本书可供从事本专业的大学师生、工厂企业技术人员学习之用。


作者:(德)格雷瑟 著,董强 译 出版社:上海交通大学出版社 出版日期:2006-4-1 ISBN:7313042361 字数:417000 印次:1 版次:1 纸张:铜版纸
目录
第1章 平板玻璃
1.1 平板玻璃简史
1.2 浮法玻璃
1.3 平板玻璃的化学成分及结构
1.4 平板玻璃的性能
1.4.1 光学性能
1.4.2 力学性能
1.4.3 热性能
1.4.4 电性能
1.4.5 化学稳定性
1.5 平板玻璃的市场
第2章 镀膜赋予了平板玻璃崭新的含义
2.1 平板玻璃深加工工艺的分类
2.2 利用表面处理技术对玻璃进行深加工
2.3 镀膜工艺及膜层
2.4 平板玻璃膜层及其要求
2.5 镀膜工艺、镀膜材料和平板玻璃表面之间的相互作用及其对膜层性能的影响
第3章 表面条件及其对膜层的影响
3.1 平板玻璃的原始表面
3.2 玻璃表面的腐蚀
3.2.1 腐蚀的起源及其对膜层的影响
3.2.2 避免和去除腐蚀层的方法
3.2.3 玻璃表面腐蚀的检查
3.3 平板玻璃表面上的杂质
3.4 平板玻璃表面在镀膜前的准备
3.4.1 对用于镀膜平板玻璃表面洁净度的要求
3.4.2 用于镀膜的平板玻璃片的清洁工艺
3.4.3 预处理后的平板玻璃表面的检查
第4章 平板玻璃的薄膜技术
4.1 薄膜技术的分类和要求
4.2 用于平板玻璃镀膜的溅射沉积真空工艺
4.2.1 在平板玻璃上镀膜的溅射工艺的应用领域
4.2.2 溅射沉积的原理
4.2.3 非反应溅射
4.2.4 反应溅射
4.2.5 溅射技术
4.2.5.1 直流和交流溅射
4.2.5.2 磁控溅射
4.2.6 平板玻璃镀膜中使用的靶材及其生产加工
4.2.7 溅射镀膜设备和工艺
4.2.7.1 箱式设备的溅射沉积
4.2.7.2 镀膜生产线的溅射沉积
4.3 用于平板玻璃镀膜的化学工艺
4.3.1 化学还原工艺
4.3.1.1 化学还原镀膜中的化学过程
4.3.1.2 采用化学还原工艺的镀膜技术
4.3.2 热平板玻璃上的化学镀膜
4.3.2.1 热平板玻璃表面上膜层的化学反应
4.3.2.2 液体喷淋技术的镀膜
4.3.2.3 化学气相沉积(CvD)技术的镀膜
4.3.3 溶胶一凝胶镀膜
4.3.3.1 溶胶一凝胶镀膜的化学过程
4.3.3.2 溶胶一凝胶镀膜技术
4.4 等离子体辅助CⅧ
第5章 薄膜平板玻璃产品
第6章 基于镀膜平板玻璃的电可控产品
第7章 基于平板玻璃的薄膜太阳能电池的光电池模块
附录
AⅠ.利用导纳法来计算膜系在阳光辐射范围内的光谱行为
AⅡ.导电膜层在长波长范围内的光谱性能的计算
AⅢ.如何计算在没有人射阳光辐射(夜晚)时的外表面温度
AⅣ.颜色及色彩重现
参考文献
第1章 平板玻璃
第2章 镀膜赋予了平板玻璃崭新的含义
第3章 表面条件及其对膜层的影响
第4章 平板玻璃的薄膜技术
第5章 薄膜平板玻璃产品
第6章 基于镀膜平板玻璃的电可控产品
第7章 基于平板玻璃的薄膜太阳能电池的光电池模块
附件
符号表
缩写
人名
地名

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Monday, May 14, 2007

Advice to a Young Scientist by Edsger W. Dijkstra

Excerpted from:
http://www.cs.utexas.edu/users/EWD/transcriptions/EWD10xx/EWD1055A.html
another one
http://math.ucr.edu/home/baez/advice.html

Raise your standards as high as you can live with, avoid wasting your time on routine problems, and always try to work as closely as possible at the boundary of your abilities. Do this because it is the only way of discovering how that boundary should be moved forward.

We all like our work to be socially relevant and scientifically sound. If we can find a topic satisfying both desires, we are lucky; if the two targets are in conflict with each other, let the requirement of scientific soundness prevail.

Never tackle a problem of which you can be pretty sure that (now or in the near future) it will be tackled by others who are, in relation to that problem, at least as competent and well-equipped as you are.

Write as if your work is going to be studied by a thousand people.

Don't get enamored with the complexities you have learned to live with (be they of your own making or imported). The lurking suspicion that something could be simplified is the world's richest source of rewarding challenges.

Before embarking on an ambitious project, try to kill it.

Remember that research with a big R is rarely mission-oriented and plan in terms of decades, not years. Resist all pressure --be it financial or cultural-- to do work that is of ephemeral significance at best.

Don't strive for recognition (in whatever form): recognition should not be your goal, but a symptom that your work has been worthwhile.

Avoid involvement in projects so vague that their failure could remain invisible: such involvement tends to corrupt one's scientific integrity.

Striving for perfection is ultimately the only justification for the academic enterprise; if you don't feel comfortable with this goal --e.g. because you think it too presumptuous--, stay out!

another one
http://math.ucr.edu/home/baez/advice.html

John Baez
March 25, 2007
I have reached the stage where young mathematicians and physicists sometimes ask me for advice. Here is my advice. Most of it applies to grad students and postdocs in any branch of science who seek an academic career involving research. The stuff on giving good talks will be helpful to almost all scientists, since most give pretty bad talks. Near the end I have a section on a more specialized question that vexes many students who email me: should I go into math or physics?
On Keeping Your Soul
Some Practical Tips
Go to the most prestigious school and work with the best possible advisor. A good advisor will give you a hot topic to work on where you can get results that people will find interesting. A good advisor will be so famous that merely being their student will cause people to be interested in you. A good advisor will go to bat for you when it comes time for you to get a job. A good advisor will be politically well-connected and lubricate your way straight to the holy groves of academe. A good advisor will also work your butt off and scare the crap out of you by expecting you to know about millions of things - don't let that put you off.

Publish. Publish papers that get definitive results on fashionable subjects, so they'll get cited. Publish papers that open up promising new lines of investigation. Publish papers that people can actually read - but don't tell anyone else this trick, or everyone will start doing it, and then where will you be? Publish papers that show you have your own research program. Publish papers that create a shock wave the moment they hit the archive! But most importantly: publish.
Go to conferences. There's an infinite number of conferences, and you should go to them. Give lots of talks, chat with lots of people, make connections, find out where the jobs are, find out what people are working on, find out what people will be working on. Have fun and be friendly. And most of all: give good talks!


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Wednesday, May 09, 2007

Harold R Kaufman


Excerpted from:
http://www.svc.org/H/H_Kaufman.html

Harold R. Kaufman is an American physicist, noted for his development of ion thrusters for NASA during the 1950's and 60's. Kaufman developed a version of the duoplasmatron for the purpose of spacecraft propulsion. ...

RS: Here we are at the 47th Annual Society of Vacuum Coaters Technical Conference in Dallas, Texas, and we have the honor of being with Dr. Harold Kaufman, one of the pioneers in the field of ion beam-assisted tools. We were hoping to get a feel from him on some of the contributions that this major development in the field has helped the rest of us get our jobs done.

RS: How did you acquire this Von Ardenne source? Was it electron based?

HK: It worked on the same principles as the electron bombardment source I worked on, but it was a single-aperture source. If you know anything about accelerating charged particles, you know you get very low currents out of a single aperture. But if you want enough current to be suitable for thrust to propel a spacecraft, you need less voltage and more current. You need to match it with the requirement. The electrons were emitted from a hot filament; they bombarded neutral atoms or molecules; the electrons were constrained by a magnetic field; and then they were electrostatically accelerated. All those parts were the same—just all the wrong proportions.

What I was able to do was to generate a large beam that could give significant thrust. That was in 1959 or 1960. Along about 1970, people became interested in modifying films with ion beams, so I had a head start on designing the sources that were needed for that sort of application.
......
RS: The original invention focused on space travel. Did you ever get to try any of these on actual spacecraft?

HK: There was a test flight in 1964, and there was another in 1970. But this is one of those fields where things move slowly. The first application did not occur until 1997. So, you can see that there was some slow motion there. I was involved in 10 or 20 mission calculations and program proposals and such. That’s one of the reasons I got interested in thin films because it was something I could do right away instead of waiting for 10 or 20 years.
......
RS: The time constant was much faster then. How did you transition from the NASA thruster approach to this ion source? Did people approach you or did you think that you might have something that could be applicable to the field?

HK: Well, a couple of people approached me. Jerry Cuomo thought it would be interesting to use these ion sources on some of the work he was doing at IBM Yorktown. He invited me to come out there for several weeks each summer. By then, I had retired from NASA, and I was working at Colorado State University.

For the first 8 or 10 weeks, I averaged one patent disclosure per week of employment. I got my post-graduate education in patents from Jerry. He was quite good at that. He taught me one of the fundamental things: If something goes horribly bad in the laboratory, you should say, “Now what can that be a real opportunity for?” You turn it around and look for a patent.

RS: Prudent advice. As you worked with these early films, what was the application that you were trying to engineer or accomplish?

HK: The early films were all really things that Jerry had been interested in. I was not a prime mover in any of the films. I worked with Jerry and with Jim Harper also, and later Steve Rossnagel—all at IBM Yorktown. Typically, they would present the problem, and we’d work together solving it. I sort of approached the films in a general way. I would come into contact with a lot of problems, and I would try to generate a few general concepts to deal with them, rather than looking at specific ones only.

RS: Did IBM allow you to practice your art in other areas or was it exclusively arranged?

HK: No. It was not exclusive. It was very generous in that we would have a patent, and IBM and I would have equal rights to the patent, which was very nice. This would help build up the patent portfolio. Very generous, and it’s easy to be productive under those conditions.
.......
RS: What do you think is one of the major accomplishments as you look around the industry and see where all of your sources are implemented? What makes you proud of some of the different devices you have developed?

HK: Oh that’s a difficult question. You must realize that a lot of us work in technology because we enjoy it. It’s a nice way to make a living. We get caught up in the pursuit. I’m not a hunter, but I suspect that looking for new knowledge must have some of the same thrill as going out and hunting for a wild animal. You get caught up in that and you don’t worry too much about some of the other things. I try to take an overall look. What I get out of the overall look is that in technology, we are a subculture of the overall whole culture we live in.

A couple of years ago I visited Mesa Verde. That made a deep impression on me. There were stone houses. People lived there in relatively secluded areas and were able to sustain their culture from about 600 A.D. to 1200 A.D. Except for little changes, like maybe some human sacrifice at the end, the culture was essentially static. 600 years. It only took us 300 years to go from Sir Isaac Newton to landing on the Moon. Something has changed in the last few hundred years so that we’ve become a very active society, technically moving ahead. Still the people who are doing it are a small fraction, maybe 1% of the total culture. I guess what impresses me more is not my particular contribution to it but rather that I am part of a subculture that is moving ahead our overall culture at a terribly fast rate compared to anything previous in history.
.........
RS: As you mentioned the future, where do you think that this technology will go? Do you foresee more use for interplanetary emissions for these thrusters? Do you see ion-assist low-voltage new devices for physical control of nanostructures?

HK: I think both of those. We are planning at present for interplanetary missions. We’re looking at all types of thrusters. That seems to be moving ahead. That one is surprising how slow it is. We landed on the Moon 35 years ago, and we never went back to it. But we do seem to be moving ahead on some of the plans to go to other planets.

I see partly the end product changing. We’re obviously going to have “smart” machines in almost everything we touch. There will be computers embedded in everything. The ion sources will increase their use. They’ve generally been competing with plasma processing. If you can do it with plasma processing, it’s probably cheaper than having a separate ion source. But the ion sources are coming down in price; they’re becoming more useful and more practical. I think that they will continue to expand in use. So will a lot of other things.

In the ion source field, it seems like we add new ion sources, new concepts, all of the time; but we don’t drop many of the old ones. The whole field becomes more complex.

RS: And broader. We’re going to conclude at this point, so if there is anything else that you would like to mention for posterity . . .

HK: Well, I’ve enjoyed this meeting, and I have particularly enjoyed the tutorial seminars. Don Mattox looking back on some of the technical developments was very interesting.
Charlie Bishop’s talk was fascinating too. He’s looking at transition. Our profit model for the past is going to disappear. We’re going to have to live more as a commodity rather than high-tech where we can charge very high prices. That’s part of a change that’s occurring. We’ll keep seeing more of those changes too. We seem to be becoming more competitive and the rate of technological development doesn’t seem to be slowing at all yet.

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Tuesday, May 08, 2007

Resent Visiting Report of Xiaobo's blog










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Monday, May 07, 2007

When to change your lab

Excerpted from:
http://sciencecareers.sciencemag.org/career_development/previous_issues/articles/3570/knowing_when_to_break_free_from_your_pi

"You should leave as soon as you feel there is more value in leaving than in staying. In the short term, staying in your current position is likely to yield more publications in high-impact journals. But, as you suspect, there is more to getting a lectureship than a compelling publication record."

"This is only one example, but we can draw some general conclusions:

Fellows are usually very attractive to universities because the fellowship has given them a chance to build an independent funding and publication record, as well as a research group. You can read more about Fellows' experiences in a recent International Career Report that was published jointly by Next Wave and Science magazine in April 2005. All institutions value a breadth of research experience. "This department looks to appoint the very best people from the best international labs, so competition is tough," explains Smith. If you only ever work with one PI, you are only seeing one approach to research. You are less likely to have learned to develop novel ideas and projects, as well as to work and think independently. If you try to argue that your existing work was based on your ideas, it begs the question, why weren't you trying to find a personal fellowship to do that work on your own?

You are still on-track for a fellowship, assuming your publication record is strong. Fellows in the International Career Report mentioned that a good time to start applying for a fellowship is between your 4th and 6th year of postdoc. That leaves you about 6 months to find a foreign postdoc and 3 years to carry it out.
......"


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Saturday, May 05, 2007

莱宝APS离子源


一年前在真空论坛许老师曾深入的讨论过此问题,由于论坛上常出现帖子丢失现象,现在将其部分内容以及自己当时的帖子整理一下,以便自用。


“以下是引用许在2005-3-30 8:53:00的发言:

莱宝APS1104光学镀膜机可以说是目前国内镀膜界的王牌。这个镀膜机主要是两台电子蒸发源何一台APS离子源组成。其APS离子源可以说是镀膜机的心脏,其结构十分独特。首先它是Kaufman型离子源,但其阴极不是常用的钨丝,而是昂贵的LaB6材料。另外其磁场不是由永久磁铁产生,而是由电磁线圈产生。从参数来看,其磁场较弱,功率也不大,但其显著特点是在被镀工件上产生的温度低,其各项参数调得使成膜时热力学平衡好,成膜致密。可以说目前国内高档光学镀膜全靠莱宝机,尽管其价格远远高于其他镀膜厂家。

再谈谈莱宝APS离子源。因为这个离子源太独特了,随APS镀膜机,特别是APS1104在国内光学镀膜界的大量采用而为许多用户。APS是Advanced Plasma Source的打头缩写。顾名思义,是先进等离子源。我开始错误的认为它是Kaufman源,后来又觉得它与霍尔源接近,其实它谁都不像,就像它自己。它有些什么特点呢?
1 用很粗大的根BLa6棒作阴极2 很长很深的阳极管包围着阴极3 另外有一个加热BLa6阴极达1500度的加热器4 另有一层法拉第屏蔽5 进气管在离子源出口而不在底部6 功率非常大,光加热器就1.8千瓦,发射功率达15千瓦根据以上特点,做点主观分析:1 BLa6阴极电子发射效率较高,热稳定性相对钨丝要好一些,可提供大电子流,较长运行时间。
2 阳极管长深对离子发射有利(电场长)
3 可将BLa6阴极加热到1500的加热器水平的确高,就像在真空室放了一个炼钢炉,如何保温,冷却。就是电磁线圈的绝缘漆就是一个难题,又要出气率低又要耐一定温度(当然不是1500,因为该离子源采用了水冷却底座)
4 法拉第屏蔽在这里可能就有点讲究,该屏蔽,阴极,阳极应该处在不同电势
5 进气管在顶部容易理解,因为底部有一个“火炉”。但整个离子源好像把气体拉进阳极管离子化后在发射出来
6 功率之大很少有其它离子源能比,但其能级却能控制在250电子伏特以下,对无栅离子源来说真不容易。
7 采用电磁线圈作磁场源看来很笨(体积大,多一套电源),但却增加了可调节参数8 由于电子流大,调节参数多,粒子流在阳极管内基本上完全中和。以上只是一些主观分析。欢迎实际用过APS离子源的同行参加讨论”
------------------------------------------------------

xbimr于2006-4-2 15:08:40编辑过

请教:
(1) “4 另有一层法拉第屏蔽”------法拉第屏蔽的作用是干什么的啊?这个不明白
(2) “ APS是Advanced Plasma Source的打头缩写。顾名思义,是先进等离子源。我开始错误的认为它是Kaufman源,后来又觉得它与霍尔源接近,其实它谁都不像,就像它自己。”------------------个人认为它可能是Kaufman与霍尔源的一个结合体:),采用用很粗大的根BLa6棒作阴极,类似欲Kaufman源那样通过外加电子来降低等离子体工作压强,或者达到增加功率密度的目的;而对于它的等离子体引出系统则是借鉴霍尔源的引出系统的原理,通过不均匀磁场之间的电位差(方向是内部高于出口)来加速在等离子体区域的离子,将它引出,这样可以采用无栅极的,也就没有什么阴极污染/烧蚀问题,此外离子流密度大小也不受所谓空间电荷限制的制约;另外从它的离子流能量分布是介于20——200EV之间,这个范围也是通常霍尔源的能量范围,估计它的能量分布范围也比较宽,这些都是霍尔源引出系统的特点,也是适用于薄膜制备的能量范围,所以用于光学镀膜。
(3) 它采用电磁线圈的原因可能在于,通过改变磁场,随即改变电位梯度,随即改变离子加速的能量,达到控制离子能量的目的?假如采用固定磁场,就少了控制控制离子能量的一个方法(4) APS离子源的离子能量对于有些薄膜,特别是关心电学性能等物理性能的薄膜植被来说,能量还是偏高了,最好应该小于20-30EV,这个范围能量的,一般是需要什么样的离子源可以达到要求,而且同时要保证相对离子流密度不能太小和不均匀??-----个人瞎掰,敬请指教:)
-----------------------------
APS等离子体源工作原理

出处:apsLaB6 2007年07月12日 11:09 阅读 57 次我单位提供质优价廉的德国Leyblod APS镀膜机国产LaB6阴极,目前已经批量生产,性能稳定,销往国内外,成功应用在德国Leyblod APS镀膜机的APS源上,所镀出的产品包括,IR-Cut Filter,紫外红外截止滤光片、红绿蓝(RGB)滤光片、窄带滤光片、二向色镜、介质高反膜、晶体镀膜,各种增透膜等镀膜产品。详细资料请来信联系: apspart@yahoo.com.cn,或留言。我们将提交相关资料供参考:性能参数、激活记录、使用记录(放电电压Vd、偏压、放电电流IC)、及实际镀膜产品的曲线。 APS是Advanced Plasma Source的缩写,原理如下图。等离子体源位于真空室底部,由LaB6阴极、阳极筒和螺旋磁场构成。圆柱形LaB6由石墨加热器直接加热。介于阳极和阴极之间的直流电压建立了一个带有电子的辉光放电等离子体,工作气体是Ar气。由于阳极筒周围螺旋磁场的作用,在磁力线方向等离子体电子迁移率迅速增加,而在阳极筒半径方向迅速减少。随着电子沿磁力线方向运动,等离子体就从阳极筒中射出,并射向基板。反应气体(O2)从阳极筒上方的管道中流出来。在高密度、高能量的等离子体的作用下,反应气体变得有活性并且部分被电离。反应气体的电离降低了反应气体的压强,这对于增加薄膜的化学计量(stoichimetry)是必需的。随着等离子体在真空室的扩张,蒸发物也被部分电离。对金属的电离是特别有效的。除了离子辅助镀的作用产生以外,也产生了电镀效果(电镀:利用电解作用使金属或其它材料制件的表面附着一层金属膜的工艺)。等离子体源与真空室的地面是绝缘的。由于等离子体中电子的高迁移率效果,产生了一个相对于真空室内壁和基板间的正的自偏压(Bias)。离子能量主要由自偏压决定。偏压的量级依赖于放电电压、磁场强度和真空室压力(Ar和O2的流量决定)。在被加速的等离子体离子的冲击及迁移下,基片表面薄膜的迁移率及填充密度就有所增加。与此同时,等离子体中的电子与膜层表面的正离子起到了中和作用,促进了等离子体对基板轰击的一致性。被电离的Ar+离在电场的作用下,对LaB6阴极溅射,这样LaB6阴极就会源源不断的产生大量的电子。等离子体高效的作用使得薄膜的增长速度可以很高,典型值可在0.5—1.5nm/s,具体值由蒸发物决定。虽然APS大部他是可用来提高生产量和性能,但是它也可用来随意的控制薄膜的性质,如密度、化学计量、折射率、甚至是薄膜的应力。


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Friday, May 04, 2007

UIUC - Professor Joe Greene

这几天SVC正在举行50th Annual SVC Technical Conference,网上看到一直很葱白的UIUC - Professor Joe Greene做大会特别报告:Design of Self-organized Nanostructures in Hard Ceramic Films with Enhanced Properties and Controlled Interfacial Structure。不由自主的想表述下心中葱白之情,但却觉得暂时了解/理解得不够深刻,不敢造次(属于盲目葱白类型,呵呵),具体待下次补充。


Up to May 2007
Results found: 220
Sum of the Times Cited :4,799
Average Citations per Item : 21.81
h-index :39


Joe Greene is the D.B. Willett Professor of Materials Science at the University of Illinois and the Tage Erlander Professor of Materials Physics at Linköping University, Sweden. The focus of his research has been the development of an atomic-level order to controllably manipulate microchemistry, microstructure, and, hence, physical properties. His work has involved film growth by all forms of sputter deposition; solid and gas-source MBE, UHV-CVD, MOCVD, and ALE. Joe has published more than 500 papers and review articles, 22 book chapters, and he has co-edited four books in the general areas of crystal growth, thin-film physics, and surface science. In particular, he has used energetic accelerated condensing species and UV photochemistry for probing as well as stimulating surface reactions that do not proceed thermally. He is currently Editor-in-Chief of Thin Solid Films and past Editor of CRC Critical Reviews in Solid State and Materials Sciences. He is active in AVS where he has served as a Trustee, as Chair of the Thin Film Division, twice as a member of the Board of Directors, as President of the Society in 1989, and currently serves on the Advanced Surface Engineering Division (ASED) Executive Committee. His major awards include the John A. Thornton Memorial Award (1991) from AVS for “outstanding research in thin films”; the Tage Erlander Award (1991) from the Swedish Natural Science Research Council for “contributions to the physics and chemistry of thin films”; Senior University of Illinois Scholar (1991) for “distinction as a member of the faculty”; an Honorary Doctor of Science Degree (1992) from Linköping University; Fellow of AVS (1993); the Technical Excellence Award from the Semiconductor Research Corporation (SRC) for “outstanding research contributions in the development of low-energy accelerated-ion doping during MBE Si and Si1-xGex film growth” (1994); the 1996 DOE Award for Sustained Outstanding Research, the 1998 David Adler Award in Materials Physics from the American Physical Society for “outstanding research and lecturing on the physics and chemistry of thin films”; Fellow of the American Physical Society (1998); the 1998 Aristotle Award from SRC for “career achievement in outstanding graduate student teaching in its broadest sense”; the D.B. Willett Professor of Engineering; the 1999 MRS David Turnbull Award for “contributions to the use of non-thermal methods in the growth of thin films and the engineering of their phase, composition, and microstructure and for excellence in teaching and writing”; the 2001 International Scientist of the Year for “contributions to thin film science;” and election to the U.S. National Academy of Engineering in 2003 for “pioneering studies in the synthesis and characterization of epitaxial and highly ordered polycrystalline materials.”
1. POWELL RC, LEE NE, KIM YW, et al.HETEROEPITAXIAL WURTZITE AND ZINCBLENDE STRUCTURE GAN GROWN BY REACTIVE-ION MOLECULAR-BEAM EPITAXY - GROWTH-KINETICS, MICROSTRUCTURE, AND PROPERTIES JOURNAL OF APPLIED PHYSICS 73 (1): 189-204 JAN 1 1993 Times Cited: 262
2. GREENE JE, SUNDGREN JE, HULTMAN L, et al.DEVELOPMENT OF PREFERRED ORIENTATION IN POLYCRYSTALLINE TIN LAYERS GROWN BY ULTRAHIGH-VACUUM REACTIVE MAGNETRON SPUTTERING APPLIED PHYSICS LETTERS 67 (20): 2928-2930 NOV 13 1995 Times Cited: 123
3. Zheng WT, Sjostrom H, Ivanov I, et al.Reactive magnetron sputter deposited CNx: Effects of N-2 pressure and growth temperature on film composition, bonding, and microstructure JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS 14 (5): 2696-2701 SEP-OCT 1996 Times Cited: 117
4. VANNOSTRAND JE, CHEY SJ, HASAN MA, et al.SURFACE-MORPHOLOGY DURING MULTILAYER EPITAXIAL-GROWTH OF GE(001) PHYSICAL REVIEW LETTERS 74 (7): 1127-1130 FEB 13 1995 Times Cited: 117
5. RAMIREZFLORES G, NAVARROCONTRERAS H, LASTRASMARTINEZ A, et al.TEMPERATURE-DEPENDENT OPTICAL BAND-GAP OF THE METASTABLE ZINCBLENDE STRUCTURE BETA-GAN PHYSICAL REVIEW B 50 (12): 8433-8438 SEP 15 1994 Times Cited: 116
6. LIN ME, XUE G, ZHOU GL, et al.P-TYPE ZINCBLENDE GAN ON GAAS SUBSTRATES APPLIED PHYSICS LETTERS 63 (7): 932-933 AUG 16 1993 Times Cited: 107
7. LUBBEN D, TSU R, BRAMBLETT TR, et al.MECHANISMS AND KINETICS OF SI ATOMIC-LAYER EPITAXY ON SI(001)2X1 FROM SI2 H6 JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS 9 (6): 3003-3011 NOV-DEC 1991 Times Cited: 105


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BOOK - Vacuum Deposition onto Webs, Films and Foils


看到一本关于Vacuum Web Coating的书,具体内容暂时没有时间来看,因此无从评论,稍后有空再做陈述。有趣的是本书作者也开了个比较有意思的真空镀膜类blog圈,包含些行业人士的blog,有兴趣的可以看看:http://www.vacuumcoatingblog.com/

Vacuum Deposition onto Webs, Films and Foils (Materials Science and Process
Technology)
by Charles Bishop (Author)
http://www.amazon.com/exec/obidos/ASIN/0815515359/aimcal-20

About the Author
Charles A. Bishop, Ph.D., C.Eng., MIMMM is an expert in vacuum deposition of thin film coatings and associated processes with almost 30 years experience. He now runs his own consultancy business. Specializing in roll-to-roll processing of webs, films and foils, his expertise covers system design, process development and system control as well as troubleshooting. Other related expertise includes optical thin film modelling, radiation cure technology, and teaching/training of vacuum technology. Dr. Bishop is the author of over 50 technical papers and 5 patents. During his time in industry he worked for ICI as a senior research scientist in Surface Engineering within the New Science Group. His diverse ICI experience encompassed wide ranging applications including Nylons (fibre surface treatment by plasma), Polyesters, Explosives(vacuum deposited pyrotechnics), Imagedata (optical data storage) and Flex Products Inc (ITO, vacuum deposited pigments).

Review
“Vacuum Deposition onto Webs, Films, and Foils is a comprehensive reference
work for anybody working in vacuum coating of polymer films. The book contains
detailed sections on all aspects of this technology, from the vacuum itself to the coating process, from winding to troubleshooting. The author has many years experience in the field, and it shows.”

Dr. A.G. Spencer - Alacritas Consultancy, Ltd.

“This new book is THE source for persons interested in roll-to-roll vacuum coating. The author displays a breadth of experience and a wealth of knowledge. The material is well organized, refreshing, comprehensive, and accessible. Experts will learn many new things, and newcomers can avoid numerous pitfalls.”

Dr. Donald J. McClure - 3M
Corporate Research Materials Laboratory --3m Corporate


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“10 Lessons of an MIT Education”by Gian-Carlo Rota

Excerpted from:
http://www.lifebang.com/archives/366
and
http://www.math.tamu.edu/~cyan/Rota/mitless.html

理工科学生需要知道的十件事
发表于Thursday, 四月 19th, 2007
一位在MIT教数学的老师总结了十条经验,对理工科学生应该很有教益:

你能够做到每天七个小时坐在书桌前。
只有在学你觉得学不会的东西时才能学到东西。
总的来说,知其所以然比知其然重要得多。
在科学和工程方面,没有人能骗太久。
并不是天才才能做有创造性的工作。
你必须对自己高标准严要求。
世界变化很快,你最好选学那些坚实恒久的学科,少赶时髦。
你永远赶不上进度,别人也一样。
未来的计算机文化是正发生在你的身边,并不是计算机文化课上学的东西。
数学仍然是科学界的女皇。

http://www.math.tamu.edu/~cyan/Rota/mitless.html

10 Lessons of an MIT Education

by Gian-Carlo Rota

Lesson One: You can and will work at a desk for seven hours straight, routinely. For several years, I have been teaching 18.30, differential equation, the largest mathematics course at MIT, with more than 300 students. The lectures have been good training in dealing with mass behavior. Every sentence must be perfectly enunciated, preferably twice. Examples on the board must be relevant, if not downright fascinating. Every 15 minutes or so, the lecturer is expected to come up with an interesting aside, joke, historical anecdote, or unusual application of the concept at hand. When a lecturer fails to conform to these inexorable requirements, the students will signify their displeasure by picking by their books and leaving the classroom.

Despite the lecturer's best efforts, however, it becomes more difficult to hold the attention of the students as the term wears on, and they start falling asleep in class under those circumstances should be a source of satisfaction for a teacher, since it confirms that they have been doing their jobs. There students have been up half the night-maybe all night-finishing problem sets and preparing for their midterm exams.

Four courses in science and engineering each term is a heavy workload for anyone; very few students fail to learn, first and foremost, the discipline of intensive and
constant work.

Lesson Two: You learn what you don't know you are learning. The second lesson is demonstrated, among other places, in 18.313, a course I teach in advanced probability theory. It is a difficult course, one that compresses the material typically taught in a year into one term, and it includes weekly problem sets that are hard, even by the standards of professional mathematicians. (How hard is that? Well, every few years a student taking the course discovers a new solution to a probability problem that merits publication as a research paper in a refereed journal.)

Students join forces on the problem sets, and some students benefit more than others from these weekly collective efforts. The most brilliant students will invariably work out all the problems and let other students copy, and I pretend to be annoyed when I learn that this has happened. But I know that by making the effort to understand the solution of a truly difficult problem discovered by one of their peers, students learn more than they would by working out some less demanding exercise.

Lesson Three: By and large, "knowing how" matters more than "knowing what." Half a century ago, the philosopher Gilbert Ryle discussed the difference between "knowing how" courses are those in mathematics, the exact sciences, engineering, playing a musical instrument, even sports. "Knowing what" courses are those in the social sciences, the creative arts, the humanities, and those aspects of a discipline that are described as having social value.


At the beginning of each term, students meet with
their advisors to decide on the courses each will study, and much of the
discussion is likely to resolve around whether a student should lighten a heavy
load by substituting one or two "knowing what" courses in place of some stiff
"knowing how" courses.

To be sure, the content of "knowing what" courses
if often the most memorable. A serious study of the history of United States
Constitution or King Lear may well leave a stronger imprint on a student's
character than a course in thermodynamics. Nevertheless, at MIT, "knowing how"
is held in higher esteem than "knowing what" by faculty and students alike. Why?

It is my theory that "knowing how" is revered because it can be tested.
One can test whether a student can apply quantum mechanics, communicate in
French, or clone a gene. It is much more difficult to asses an interpretation of
a poem, the negotiation of a complex technical compromise, or grasp of the
social dynamics of a small, diverse working group. Where you can test, you can
set a high standard of proficiency on which everyone is agreed; where you cannot
test precisely, proficiency becomes something of a judgment call.

At certain liberal arts colleges, sports appear to be more important than classroom
subjects, and with good reason. A sport may be the only training in "knowing
how"-in demonstrating certifiable proficiency-that a student undertakes at those
colleges. At MIT, sports are a hobby (however passionately pursued) rather than
a central focus because we offer a wide range of absorbing "knowing how"
activities.

Lesson Four: In science and engineering, you can fool very
little of the time. Most of the sweeping generalizations one hears about MIT
undergraduates are too outrageous to be taken seriously. The claim that MIT
students are naive, however, has struck me as being true, at least in a
statistical sense.

Last year, for example, one of our mathematics
majors, who had accepted a lucrative offer of employment from a Wall Street
firm, telephoned to complain that the politics in his office was "like a soap
opera." More than a few MIT graduates are shocked by their first contact with
the professional world after graduation. There is a wide gap between the
realities of business, medicine, law, or applied enginering, for example, and
the universe of scientific objectivity and theoretical constructs that is MIT.

An education in engineering and science is an education in intellectual
honesty. Students cannot avoid learning to acknowledge whether or not they have
really learned. Once they have taken their first quiz, all MIT undergraduates
know dearly they will pay if they fool themselves into believing they know more
than is the case.

On campus, they have been accustomed to people being
blunt to a fault about their own limitations-or skills-and those of others.
Unfortunately, this intellectual honesty is sometimes interpreted as naivete.

Lesson Five: You don't have to be a genius to do creative work. The idea
of genius elaborated during the Romantic Age (late 18th and 19th centuries) has
done harm to education. It is demoralizing to give a young person role models of
Beethoven, Einstein, and Feynman, presented as saintly figures who moved from
insight to insight without a misstep. Scientific biographies often fail to give
a realistic description of personality, and thereby create a false idea of
scientific work.

Young people will correct any fantasies they have about
genius, however, after they come to MIT. As they start doing research with their
professors, as many MIT undergraduates do, they learn another healthy lesson,
namely, a professor may well behave like a fumbling idiot.

The drive for
excellence and achievement that one finds everywhere at MIT has the democratic
effect of placing teachers and students on the same level, where competence is
appreciated irrespective of its provenance, Students learn that some of the best
ideas arise in groups of scientists and engineers working together, and the
source of these ideas can seldom be pinned on specific individuals. The MIT
model of scientific work is closer to the communion of artists that was found in
the large shops of the Renaissance than to the image of the lonely Romantic
genius.

Lesson Six: You must measure up to a very high level of
performance. I can imagine a propective student or parent asking, "Why should I
(or my child) take calculus at MIT rather than at Oshkosh College? Isn't the
material practically identical, no matter where it is taught, while the cost
varies a great deal?"

One answer to this question would be following:
One learns a lot more when taking calculus from someone who is doing research in
mathematical analysis than from someone who has never published a word on the
subject. But this is not the answer; some teachers who is doing research in
mathematical analysis than from someone who has never published a word on the
subject. But this is not the answer; some teachers who have never done any
research are much better at conveying the ideas of calculus than the most
brilliant mathematicians.

What matters most is the ambiance in which the
course is taught; a gifted student will thrive in the company of other gifted
students. An MIT undergraduate will be challenged by the level of proficiency
that is expected of everyone at MIT, students and faculty. The expectation of
high standards is unconsciously absorbed and adopted by the students, and they
carry it with them for life.

Lesson seven: The world and your career are unpredictable, so you are better off learning subjects of permanent value. Some students arrive at MIT with a career plan, many don't, but it actually doesn't matter very much either way. Some of the foremost computer scientists of our day received their doctorates in mathematical logic, a branch of mathematics that
was once considered farthest removed from applications but that turned out
instead to be the key to the development of present-day software. A number of
the leading figures in experimental molecular biology received their doctorates
in physics. Dramatic career shifts that only a few years ago were the exception
are becoming common.

Our students will have a harder time finding
rewarding jobs than I had when I graduated in the fifties. The skills the market
demands, both in research and industry, are subject to capricious shifts. New
professions will be created, and old professions will become obsolete with the
span of a few years. Today's college students have good cause to be apprehensive
about future.

The curriculum that most undergraduates at MIT choose to
follow focuses less on current occupational skills than on those fundamental
areas of science and engineering that at least likely to be affected by
technological changes.

Lesson Eight: You are never going to catch up,
and neither is anyone else. MIT students often complain of being overworked, and
they are right. When I look at the schedules of courses my advisees propose at
the beginning of each term, I wonder how they can contemplate that much work. My
workload was nothing like that when I was an undergraduate.

The
platitudes about the disappearance of leisure are, unfortunately, true, and
faculty members at MIT are as heavily burdened as students. There is some
satisfaction, however, for a faculty member in encountering a recent graduate
who marvels at the light work load they carry in medical school or law school
relative to the grueling schedule they had to maintain during their four years
at MIT.

Lesson Nine: The future belongs to the
computer-literate-squared. Much has been said about computer literacy, and I
suspect you would prefer not to hear more on the subject. Instead, I would like
to propose the concept computer-literacy-squared, in other words computer
literacy to second degree.

A large fraction of MIT undergraduates major
in computer science or at least acquire extensive computer skills that are
applicable in other fields. In their second year, they catch on to the fact that
their required courses in computer science do not provide the whole story. Not
because of deficiencies in the syllabus; quite the opposite. The undergraduate
curriculum in computer science at MIT is probably the most progressive and
advanced such curriculum anywhere. Rather, the students learn that side by side
with required courses there is another, hidden curriculum consisting of new
ideas just coming into use, new techniques and that spread like wildfire,
opening up unsuspected applications that will eventually be adopted into the
official curriculum.

Keeping up with this hidden curriculum is what will
enable a computer scientist to stay ahead in the field. Those who do not become
computer scientists to the second degree risk turning into programmers who will
only implement the ideas of others.

Lesson Ten: Mathematics is still the
queen of the sciences. Having tried in lessons one through nine to take an
unbiased look at the big MIT picture, I'd like to conclude with a plug for my
own field, mathematics.

When an undergraduate asks me whether he or she
should major in mathematics rather than in another field that I will simply call
X, my answer is the following: "If you major in mathematics, you can switch to X
anytime you want to, but not the other way around."

Alumni who return to
visit invariably complain of not having taken enough math courses while they
were undergraduates. It is a fact, confirmed by the history of science since
Galileo and Newton, that the more theoretical and removed from immediate
applications a scientific topic appears to be, the more likely it is to
eventually find the most striking practical applications. Consider number
theory, which only 20 years ago was believed to be the most useless chapter of
mathematics and is today the core of computer security. The efficient
factorization of integers into prime numbers, a topic of seemingly breathtaking
obscurity, is now cultivated with equal passion by software desigers and code
breakers.

I am often asked why there are so few applied mathematicians
in the department at MIT. The reason is that all of MIT is one huge applied
mathematics department; you can find applied mathematicians in practicially
every department at MIT except mathematics.


From the Association of
Alumni and Alumnae of MIT April 1997




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Wednesday, May 02, 2007

Business skills for science and technology ---- Courses

I would like to recommend a highly valuable website for the people who are probably interested in R&D management.

http://www.richardreeves.net/index.htm


Website of Richard Reeves
Courses available from Richard. Links to other tutors who used to provide courses for the R&D Management Centre.Briefing Papers.Information about R&D Management.

About R&D
An introduction to R&D Management
A practitioner's recommended booklist
A practitioner's recommended papers


Definition - What is R&D?

The term “Research and Development” is widely used to describe the activity in a company where scientists and engineers are employed to extend the science or technology underlying the company’s work and to develop new products, processes or services. A company that fails to improve its products and replace those that become obsolete will suffer declining profitability due to the activities of competitors and the advance of technology generally. Some leading companies claim that thirty per cent of their revenues at any one time are due to products developed in the previous three years. In more mature sectors of industry the pace of change is slower, but profit margins tend to be smaller in mature sectors and relatively small advances become important.

Contents
Introduction
New Thinking
The Nature of R&D
Creating Intellectual Capital
Three Generations of R&D
R&D & The Company
Types of Work Undertaken by R&D
Financial Appraisal of R&D
Defining the R&D task
Management tools
Stage-gate® management of New Product Development
Management of the R&D portfolio
Organisation and staffing
Management structure and location of R&D
R&D Staffing
All change in R&D
Independent R&D
The problem of basic research
Technology Foresight
References and further reading
For further information


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Tuesday, May 01, 2007

"Industrial Postdocs" By Rick H। Fields

Excerpted from the website: http://sciencecareers.sciencemag.org/career_development/previous_issues/articles/0140/industrial_postdocs_the_pros_and_cons_of_doing_an_industrial_postdoc

This is a short essay concerning the advantage and disadvantage of doning an industrial postdoc. Interestingly, the author is a postdoc in thin film materials science as same as we do. So it is more valuable to help us to make a suitable choice. According to author's opinion and experience, as an industial postdoc you will learn much knowledge that can't gain from textbook and academic journal, cooperate with talented engineers and scientists in a wide variety of disciplines, and obtain a competitive salary, but in the same time, you will likely face a stifling environment which would confine and limit your productivity. Of course, we should consider the author is working in a large industrial reasearch center in USA, and his case may be different from that of us, thus the conclusion is also circumstantial.

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Industrial Postdocs: The Pros and Cons of Doing an Industrial Postdoc

Rick H। Fields United States6 August 1999
BACK TO THE FEATURE INDEX
CHOOSING AN INDUSTRIAL POSTDOC TO FINALLY GET A LIFE
SIMILARITIES AND DIFFERENCES BETWEEN INDUSTRIAL AND ACADEMIC POSITIONS IN THE PHARMACEUTICAL INDUSTRY
THE WAVE OF THE PRESENT

Rick H। Fields is a Thin Film Materials Science postdoc working in a large industrial research center in California. His name has been changed to protect his identity.

As long back as I can remember, I always intended to obtain a doctorate degree in the sciences। As my father had done, I planned on joining the ranks of industrial researchers to advance technology for the profit of the company, the benefit for consumers, and possibly society. During my graduate career, I visited and interacted with many researchers from industrial, national, and university laboratories. I was truly fortunate in that I had numerous possibilities after graduation. However, my goal of obtaining a permanent research staff position at a California company limited my choices to a handful of companies. From the beginning, my job search focused on a particular company. Let's call them Company X. I was attracted by the productivity of numerous highly respected scientists of Company X's research center.

Despite being actively recruited by Company X, I was unable to secure a permanent research position as I had hoped। Instead, I was offered a postdoctorate position by a reputable researcher at the company. Despite my high ambitions, I decided that an industrial postdoc would provide me with extensive exposure within the company and potentially lead to a permanent position. The experience would also make me attractive to other potential future employers. Eighteen months have passed since I made the decision. I will try to shed light on the positives and negatives of pursuing an industrial postdoc position based on my experience and that of fellow industrial postdocs.

High-tech companies hire industrial postdocs as a recruitment tool and to do exploratory research beyond the scope of the designated program। If one has not decided whether to pursue an academic or industrial career, an industrial postdoc position is an excellent opportunity to observe the environment and demands of an industrial researcher. The secrecy and motivations behind industrial or applied research is an entirely foreign world for most graduate students when emerging from an academic environment. You will be reeducated in terminology and processes not listed in graduate textbooks or academic journals. You may find yourself operating state-of-the-art research and manufacturing equipment supported by an active supporting staff of technical engineers. The competitive race for cutting-edge technology requires large-scale but selective capital investment by high-tech companies. The highlight of my postdoc experience is my professional and personal associations with the collection of motivated and talented engineers and scientists. These experts were readily available to dispense advice regarding a wide variety of disciplines and problems. An advantage of the "temporary employee" status of postdocs is that I was "excused" from most of the bureaucratic requirements imposed by corporate management. Financially, industrial postdocs are paid competitively with similar positions at national labs and considerably more than academic postdocs. Industrial postdocs are also invited to participate in the company stock purchase plan and other employee discount programs.

The disadvantages of being an industrial postdoc are numerous and complicated। Your experience may vary greatly from mine depending on the industry, corporate culture, your attitude, and your supervisor. Being in industry, one must naturally expect to focus on an aspect related to commercial technology. Basic science research does exist within industry, but such opportunities are few and with limited funding due to marginal interest from management. Because you are regarded as a temporary employee, the company is obliged to protect its many industrial secrets by denying you access or exposure. I found this unbelievably frustrating and detrimental to my scientific development. Despite the availability of experts and equipment, I became aware very quickly of the limits and closed doors. I am not permitted to attend the weekly group meetings nor other internal discussions. I flourished in the openness of the academic setting, but wilted in this stifling environment. After some time, one simply loses interest in the projects of the other group members. To avoid disclosure problems, you may be assigned projects only distantly related to product level technology; however, if your research results suggest a new area of unlicensed technologies, you will experience great difficulty in publishing or disclosing your work outside of the company. All external publications and presentations must go through a process of managerial approval to determine if the research results are proprietary. Similarly, internal collaborations are encouraged but limitations to external collaborations exist due to financial and proprietary constraints.

There are a number of more subtle and circumstantial disadvantages to the industrial environment। If you design and construct an analytical or characterization tool, your association with the equipment can create the dangerous situation of being reduced to a glorified technician. Postdocs in this position resented the narrow focus of their position and felt abused. In the industrial management scheme, a hierarchy of decision-making and control exists where the focus of research is often dictated from above. The external control can create situations of unwanted interference. I soon also realized that my position placed me at the bottom of the pyramid of power. The progress of my work was impeded by delays because my samples were often deemed "low priority." As a postdoc, you are granted a limited travel budget to attend conferences in your field which is subjected to managerial approval. Despite the competitive pay as a postdoc, the postdoc salary is only 50% to 70% of that of the researchers and supporting engineering staff. Due to the temporary employee status, I am denied certain benefits given to permanent employees such as a dental plan and contributions to a retirement account. Postdocs are not eligible for pay increases during the length of their contract and ineligible for variable pay such as bonuses. Finally, working for 2 years for a company does not guarantee any position, let alone a research position. Many of the retained postdocs are often placed in engineering positions due to the lack of new research positions.

During the 18 months of my postdoc, I often asked myself if I would have made the same decision. Although I am very happy with my fellow co-workers, I continually suffered from an overwhelming sense of frustration that never abated. I found the environment to be confining and it limited my productivity. I wanted to contribute more, but my enthusiasm was often doused by the policy of confidentiality. In hindsight, I probably should have increased my options and pursued my goal of a permanent industrial position to greater lengths. In the months remaining in my postdoc, I will seek a permanent position at an industrial research center. The change in status may eliminate the frustration of closed doors, but I realize that many of the limitations I listed are intrinsic to the industrial environment.

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