当军品材料民用化，就有了——陶瓷手表！

表在表壳表带使用陶瓷材料的，首屈一指当属雷达RADO。而且，还被雷达手表说成是“高技术陶瓷（HIGH-TECH CERAMICS）”和“太空材料”，它的手表产品系列中的拱型、银钻、精密陶瓷、整体陶瓷、恒星、赛瑞克斯等都使用了陶瓷的表壳和表带。

所谓的太空材料，主要是指美国航天飞机上面用的隔热瓦，能耐几千度的高温，那种材料也是陶瓷的，估计性质上和雷达手表上陶瓷材料是一样的。美国“哥伦比亚”号航天飞机，就是因为在起飞的时候，左翼上的隔热瓦被砸受损，在航天飞机返航的时候，不能抵御和大气层摩擦产生的高温，导致空中解体而失事的。

陶瓷也好，高技术陶瓷也罢，首先这个材料是比较现代，还有，就是其表面非常光洁、特耐磨、物理性质稳定、耐酸碱、抗腐蚀、不会变色脱色、质量很轻、而且无公害。它还不伤皮肤，而不锈钢表壳表带里面有镍金属，镍对人的皮肤不好，很多人都会过敏的。高科技陶瓷的制造工艺，是将极精细的氧化锆粉末，把粉末以高压注入模内后，在摄氏一千多度高温的烧结炉内结成不易磨损陶瓷部件，再以用钻石粉末打磨，方可制成。因此，它还算是粉末冶金。

手表的重量，也一直是个恼人的问题。如果是表壳直径比较大而且有一定厚度的手表，再配上不锈钢的实芯表带，那就差不多要有150克的重量了，带在手上确实比较坠手腕的。高技术陶瓷似乎比钛材料还要轻，别看它的表带比较厚，但是，表带内部都是用的塑料的支撑件，（精密陶瓷款的除外）就是这种表带在拆卸表带节的时候比较麻烦点。

高技术陶瓷还可以做成各种颜色的，比较常见的有黑色、银灰色、金色、蓝色、白色等颜色的。其中，以黑色的为最多，被称为“黑陶”。

至于手表上的陶瓷材料有什么缺点，我个人总结有这么几点：（1）棱角不太分明，表壳或表带形状基本上都是圆鼓隆冬的；（2）容易碎裂，比较怕摔和怕磕碰。（3）表带节之间缝隙过大，尤其是银钻系列的，它的表带和表壳连接处（第一节）缝隙特大，在佩带者手腕比较细的情况下，尤为明显。这样的话，一则不美观，二则也容易进去脏东西。

关于雷达陶瓷材料的手表的陶瓷表带节碎裂残损的情况，在售后维修上屡见不鲜。很多消费者都信誓旦旦的说，手表并没有被摔到地上，但是表带节还是碎裂或蹦瓷，更有严重的，是当换上新的表带节后，居然没过多长时间就又坏掉。从残损的手表部位上分析，发现全都是破碎在表带的穿钉轴的位置。这个说明破裂是由于穿钉轴变形造成的，穿钉轴变形和表带受力拉撑，按装表带时候手法不对都有关系。雷达精密陶瓷的手表，还比较好，陶瓷表带节很少见有坏的，因为它有个工字型的表带框架。对于整体陶瓷和银钻系列的手表，在佩带时候，尤其要格外小心，它的陶瓷部件比较多，也比较大，更容易发生损坏。

申请国外博士后的好网站

申请国外博士后的好网站 请国外博士后的好网站 http://www.academictransfer.nl/org/http://www.postdocjobs.com/http://www.sciencejobs.comhttp://scijobs.org/http://recruit.sciencemag.org/http://www.nature.com/naturejobs/http://www.ccom/areerpath.http://www.jobsunlimited.com/http://www.newscientistjobs.com/http://www.smth.org/bbscon.php?board=AdvancedEdu&id=6371.英国：http://jobs.ac.uk/ 每天更新，2.德国马普研究所 http://www.mpg.de/english/institut/3.AIP工作信息: http://www.aip.org/careersvc/jobs/ 综合（很多国家）：或者 http://careers.physicstoday.org/search/其他有用地址：http://www.phdjobs.com/ (分专业）http://www.post-docs.com/http://www.aps.org/jobs/http://tiptop.iop.org/其他联系大学可以从 yahoo-教育－国家...往下找。学校排名可以从清华BBS查。现提供几个几乎所有重要综合性科学期刊都有博士后广告，每个著名学院，大学，研究院所甚至公司都有各自招聘信息在自己网站上几个著名的招聘网，http://www.postdocjobs.com/ http://www.newscientistjobs.com/splash.actionhttp://aaas.sciencecareers.org/js.php?q=postdoctoral+positionshttp://www.postdocjobs.com/jobs/国家留学基金委员会http://www.csc.edu.cn/gb/2007年国家留学基金资助出国留学项目指南http://www.csc.edu.cn/gb/downloaddoc/2007/xmzn.htm澳大利亚悉尼大学博士生、博士后项目http://www.csc.edu.cn/gb/downloaddoc/2007/项目指南/澳大利亚悉尼大学博士生、博士后项目.doc中德DAAD精英奖学金项目http://www.csc.edu.cn/gb/downloaddoc/2007/项目指南/中德DAAD精英奖学金项目.doc(1) JobMart, which is updated regularly (May find faculty positions also). http://www.kumc.edu/rrsnews/JobMart.htm#PostDoc(2) NMRInfo, which is a list related to NMR spectroscopy/imaging and will be updated regularly. http://www.spincore.com/nmrinfo/ (click "Positions" on the left side Menu)(3) SMI (The Society of Molecular Imaging). As the name can tell, it is related to molecular imaging, such as MRI, CT, PET, etc. http://www.mi-careers.org/cgi-bin/view.cgi(4) To browse the personal webpage of famous professors in your field, you may probably find a suitable position! http://www.sciencenet.cn/bbs/showpost.aspx?id=6510

中国期刊网文献如何导入Endnote

Referworks与Endnote

使用中国知网-CNKI进行文献检索时，勾选要导出的文献记录，点击存盘，即显示结果输出页，其中的Referworks可以帮助你导出研究结果到参考文献管理软件，例如Endnote。请按以下步骤具体操作如何将Referworks数据导入到Endnote。

第一步

从http://www.lib.unimelb.edu.au/endnote/filterfiles/CNKI.enf下载filter，并将其复制到你电脑中Endnote安装目录的filters文件夹中。

第二步

1、打开Endnote
2、点击File菜单，选择New来新建一个参考文献库（当然也可打开现有的文献库）
3、点击import，弹出一个对话框
4、点击choose file 来选择刚下载的RefWorks.txt，在import option中选择CNKI filter。如果它不在列中，点击other filters来找
5、在text translation中选择Unicode（UTF-8）
5、点击import来完成整个导入过程，你会发现所有在CNKI搜索结果中的文献已经被导入到Endnote了

Going to buy a used car!!!

As is known, it's really inconvenient to live without a car in USA. I just want to do some "homework" on how to buy a used car from the internet!

Here within is some related Ref:

With economics a major problem, used cars have become great alternatives to people who do not have much to spare in the financial area. Finding used cars is not really a problem as there are thousands of used cars outlets in the country. Buyers of used cars will, in fact, have a wide range of models and brands to choose from.But as these cars are already well used, it is important for buyers to understand the dynamics of buying a used car to ensure that they are getting value for their money.

Here are some tips that any buyer can take heart whether they are buying used or brand new automobiles.

Scout for the perfect deal The principle of collect and collect, then select also applies in buying a used car. Remember that used car outlets need you more than you need them, so make the most of this special privilege and look not only for the better but for the best car and the best deal.

Used car outlets, in fact, have special promos and deals that you can avail of. Some offer discounts, rebates and even installment payments while others opt for free services like changing of tire or cleaning.

Wait up for a good deal. For though you are not paying full price for the car, you still deserve quality from the payment that you are going to make. After all, whether it is brand new or a car already used, it will still put a huge dent on your budget. So you better make the most out of every penny that you will be shelling out.

Give yourself time When buying or scouting for a used car, it is important that you give yourself ample time to look for one. Otherwise you will only end up buying a used car that you will not be using after a couple of months.

Giving yourself no time to decide and choose will only make you settle for a used car that is not really what you are looking for. This may be well and good for a brand new car because at least with a new one, you will not have to think about the wear and tear. Buying a used car in a hurry is suicide in more ways than one, because you are also compromising your safety when you choose in haste.

Be aware of the lemon law in your state The Lemon Law covers both used and brand new cars. While different states have different policies for used cars under the Lemon Law, basically, it gives you the same coverage. If you find that a used car is sold to you under false pretenses or did not function the way it was supposed to function in accordance to the guidelines, you have the right as a consumer to invoke the Lemon Law.

Buy from a friend Buying a used car from friends who you know is way better than buying used cars sold in shops. For unless you have an eye for quality used car, you might end up buying a junk that you will not be able to use in the long run. If you know people who are selling their used cars at lower costs not because the cars are already worn but because they are buying new models, thats better. Its better to buy the used cars from private individuals because in a way you know how the car was used.

Ask for referrals It is also a good idea to ask the help of people who have already bought used cars, as they will be able to guide you with the entire procedure as well as refer you to the right store and person that can help you choose a quality used car. They can also refer you to a reputable used car store that they have already tried. This way, you can be assured of the quality of product and service.

Dont be afraid to ask your friends, relatives or colleagues at work. Youll find that they are more than willing to help someone. After all, nothing boosts the ego than the thought that they can be experts in one subject.

Silicon Nanowires Upgrade Data-Storage Technology

Scientists at the National Institute of Standards and Technology (NIST), along with colleagues at George Mason University and Kwangwoon University in Korea, have fabricated a memory device that combines silicon nanowires with a more traditional type of data-storage. Their hybrid structure may be more reliable than other nanowire-based memory devices recently built and more easily integrated into commercial applications.

Centered is a photo of a ZnO nanowire array on a 4 inch silicon wafer. It is surrounded by images of the array at different locations and magnifications. Scale bars, clockwise from upper left, correspond to 2 µm, 500 nm, 200 nm, and 1µm.

As reported in a recent paper,* the device is a type of “non-volatile” memory, meaning stored information is not lost when the device is without power. So-called “flash” memory (used in digital camera memory cards, USB memory sticks, etc.) is a well-known example of electronic non-volatile memory. In this new device, nanowires are integrated with a higher-end type of non-volatile memory that is similar to flash, a layered structure known as semiconductor-oxide-nitride-oxide-semiconductor (SONOS) technology. The nanowires are positioned using a hands-off self-alignment technique, which could allow the production cost—and therefore the overall cost—of large-scale viable devices to be lower than flash memory cards, which require more complicated fabrication methods.

The researchers grew the nanowires onto a layered oxide-nitride-oxide substrate. Applying a positive voltage across the wires causes electrons in the wires to tunnel down into the substrate, charging it. A negative voltage causes the electrons to tunnel back up into the wires. This process is the key to the device’s memory function: when fully charged, each nanowire device stores a single bit of information, either a “0” or a “1” depending on the position of the electrons. When no voltage is present, the stored information can be read.

The device combines the excellent electronic properties of nanowires with established technology, and thus has several characteristics that make it very promising for applications in non-volatile memory. For example, it has simple read, write, and erase capabilities. It boasts a large memory window—the voltage range over which it stores information—which indicates good memory retention and a high resistance to disturbances from outside voltages. The device also has a large on/off current ratio, a property that allows the circuit to clearly distinguish between the “0” and “1” states.

Two advantages the NIST design may hold over alternative proposals for nanowire-based memory devices, the researchers say, are better stability at higher temperatures and easier integration into existing chip fabrication technology.

* Q. Li, X. Zhu, H. Xiong, S.-M. Koo, D.E. Ioannou, J. Kopanski, J.S. Suehle and C.A. Richter. Silicon nanowire on oxide/nitride/oxide for memory application. Nanotechnology 18 (2007) 235204.

Contact: Michael E. Newman michael.newman@nist.gov 301-975-3025 National Institute of Standards and Technology (NIST)

Image Credit: COPYRIGHT STATUS: LBNL (Lawrence Berkeley National Laboratory) authored documents are sponsored by the U.S. Department of Energy under Contract DE-AC02-05CH11231. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce these documents, or allow others to do so, for U.S. Government purposes.

These documents may be freely distributed and used for non-commercial, scientific and educational purposes. Commercial use of the documents available from this server may be protected under the U.S. and Foreign Copyright Laws.

Merry Christmas!

It's really exciting to have a good travel to Napa and San Francisco this Christmas. The unforgetable Golden Gate Bridge, Twin Peaks, Bay Bridge Pier, Pier 39 (Fisherman's wharf), City Hall, ChinaTown... scene, the dilicious Chinese cuisine food are still clear in my mind. 3 busy days, a close to the U.S. culture and big city life.


After that, I have to shoot with the NSF left by Prof. Shen and the whole day long. Just feel so tired about it!!!

Better Body Armor Expected from New Material Formation Process Developed at Georgia Tech

Professor Robert Speyer and his research team have created a new boron carbide formation process. The method yields higher relative densities -- thus better ballistic performance -- than currently available boron carbide armor. Here, Speyer holds a prototype thigh plate.

A Georgia Institute of Technology researcher has developed a process that increases the hardness and improves the ballistic performance of the material used by the U.S. military for body armor. The researcher's start-up company is commercializing the technology.

Boron carbide is the Defense Department’s material of choice for body armor. It is the third hardest material on earth, yet it’s extremely lightweight. But it has an Achilles heel that piqued the interest of Georgia Tech Professor of Materials Science and Engineering Robert Speyer five years ago.

He knew that the boron carbide powder used to form the armor had a reputation for poor performance during sintering -- a high-temperature process in which particles consolidate, without melting, to eliminate pores between them in the solid state. Poor sintering yields a more porous material that fractures more easily – not a good thing for a soldier depending on it to stop a bullet.

Determined to understand the sintering problem, Speyer built an instrument called a differential dilatometer to measure the expansion and contraction of materials during sintering heat treatments to temperatures as high as 4,300 degrees Fahrenheit.

“As a particle compact sinters, it shrinks 12 to 15 percent,” Speyer explained. “There are nuances that occur in contraction, and if you monitor them accurately (with a dilatometer), it tells you what is happening at different stages in the sintering process. So we used that information in conjunction with additional materials characterization techniques to figure out the reasons why boron carbide didn’t sinter well, and then found ways around them.”

From these findings, Speyer and his research team have created a new boron carbide formation process based on methodical control of thermal and atmospheric conditions during sintering. The method yields higher relative densities – and thus better ballistic performance – than currently available boron carbide armor.(Relative density is a percentage that indicates how close a material is to its theoretical density, which implies having no pores.)

A new boron carbide formation process allows for the creation of complicated, curved shapes for use in helmets and other body armor. Here, a small-scale prototype helmet is shown.

The research has been reported in the Journal of Materials Research.

The current commercial process, called hot pressing, squeezes boron carbide powders together between large dies, while heating to elevated temperatures. It yields armor materials with a 98.1 percent relative density.

Speyer’s pressureless sintering method yields a 98.4 percent relative density and hardness greater than hot pressing. But it can be done faster and at a lower cost than hot pressing. For the most demanding applications, post-sintering hot isostatic pressing (HIP) is used. It increases the relative density of the part to 100 percent through the hydrostatic squeezing action of a high-temperature, high-pressure gas.

“Our material made using HIP is remarkably harder than the current ceramic armor used in the Iraq and Afghanistan theaters,” Speyer said. “Plus, because we’re not using uni-axial hot pressing, we can make complicated, curved shapes for use in form-fitting body armor and other applications. Hot pressing allows for some curvature so long as the parts can stack together, but there’s no chance of making parts like a single-piece helmet.”

A new boron carbide formation process allows for the creation of complicated, curved shapes. Here, a nozzle made from the material is shown.

To make such products, Speyer has formed a company called Verco Materials under the advisory support of Georgia Tech’s VentureLab, which helps faculty members commercialize their research. Ceramics expert Beth Judson is the company’s general manager, and Jon Goldman is the VentureLab commercialization catalyst helping Verco get started. A Georgia Tech patent on Speyer’s sintering process for boron carbide
is pending, and when granted, Verco will have access to an exclusive license, Judson said.

The company has received two technology commercialization grants – totaling $100,000 -- from the Georgia Research Alliance to fabricate prototypes for potential military and industrial customers. The Georgia Tech Rapid Prototyping and Manufacturing Institute assisted with fabrication of model armor shapes. Also, VentureLab continues to analyze the company’s potential markets.

Beyond body armor, potential military applications include aircraft/rotorcraft protective components. Civilian markets include industries “that can exploit the phenomenal abrasion resistance of theoretically dense boron carbide,” Speyer said.

The micrograph on the left depicts the historically typical porous microstructure of pressureless sintered boron carbide. At right is a theoretically dense boron carbide microstructure that was pressureless-sintered and post-hot isostatic pressed based on research by Professor Robert Speyer.

Products manufactured by these industries include bearings, blast nozzles, cutting and mining tools, and pump and turbine shafts. The military market is growing rapidly with more than a half billion dollars worth of ceramic armor orders pending in this fiscal year, Goldman noted. That market is expected to double by 2009, according to a recent report in the publication Ceramic Industry. Bearings are a $27 million market with 5.7 percent annual growth expected through 2007.

Military applications – body armor, in particular – would be Verco’s first target market, and its potential is promising, Speyer noted. The U.S. Army Soldier Systems Center in Natick, Mass., has conducted ballistic testing on a small boron carbide disk provided by Verco. Detailed results are classified, but the Army says they are encouraging. With a $75,000 grant from the center, Verco will produce 6- by 6-inch plates for more comprehensive military ballistic testing within the next few months.

Early next year, the Army Research Laboratory (ARL) at the Aberdeen Proving Ground in Maryland will be examining boron carbide materials (including complex shapes) they purchased from Verco. ARL is interested in Verco’s potential ability to form complex shapes cost effectively.

Meanwhile, Verco expects to make thigh and shin plate prototypes in early 2006 for a Johnstown, Penn., company called Concurrent Technologies Corporation (CTC). The plates will be evaluated for use in CTC’s Ballistic Gauntlet, a new lower-body armor product for use in military and commercial vehicles in war zones to protect against the pervasive threat of improvised explosive devices. It was the idea of CTC engineer Scott Burk, who recently served in the Persian Gulf for 21 months.

The company’s current design calls for the Ballistic Gauntlet’s thigh and shin plates to be made from titanium, but its cost has risen recently, and it’s hard to form and heavier than boron carbide, Judson and Goldman said.

In one other effort, Verco and the Georgia Tech Research Institute (GTRI) are collaborating. GTRI has developed a composite armor “blast bucket” for the ULTRA AP, a concept vehicle designed to illustrate potential technology options for improving survivability and mobility in future military combat vehicles. Verco and GTRI hope to modify the “blast bucket” by replacing heavier ceramic spheres with lightweight boron carbide spheres in the composite structure to make it attractive for use in new helicopters, as well as in retrofitting current rotorcraft, Judson said.

If Verco gets initial defense-related contracts from the customers it is courting, the company would need a tremendous productive capacity – enough to make thousands of parts a week, Judson and Goldman said. Plans call for a highly automated manufacturing facility in Georgia that would initially hire a significant number of engineering and manufacturing employees.

---

RESEARCH NEWS
& PUBLICATIONS OFFICE
Georgia Institute of Technology
75 Fifth Street, N.W., Suite 100
Atlanta, Georgia 30308 USA

MEDIA RELATIONS CONTACT:
John Toon (404-894-6986); E-mail: (john.toon@edi.gatech.edu).

WRITER: Jane Sanders