动态特性的参数设计在差示光度法测金中的应用

本文提出对动态特性参数设计使用相关系数与信噪比作为内表指标进行分析 ,并使用该分析方法优化了差示光度法测较高浓度金矿样的试验条件。     

Synthesis and characterization of surface‐initiated polymer brushes on silicon substrates by reversible addition fragmentation chain transfer polymerization

Polymer brushes were prepared by using the reversible addition fragmentation chain transfer (RAFT) technique. The silicon substrates (Si (111) surface) were modified with ethyl xanthate groups which were introduced by the treatment of Si (111) surface with sodium ethyl xanthate. The polymer brushes were then prepared under RAFT conditions from the Si (111) wafer. Its “living” characteristics were determined by a series of characterizations including gel permeation chromatography (GPC), ellipsometry, and contact angle measurements. The results showed a well‐defined graft layer consisting of polymer brushes with low‐polydispersity could be prepared directly on Si (111)‐X surface (where X represents an ethyl xanthate groups). The structure of the polymer brushes was characterized and confirmed with the surface sensitive techniques such as X‐ray photoelectron spectroscopy (XPS) and scanning probe microscopy (SPM). Copyright © 2007 John Wiley & Sons, Ltd.     

Novel NO2 Gas Sensor Based on Cr(III) Complex Thin Film

The results concerning the gas‐sensing characteristics of novel NO₂ gas sensors, fabricated from complex [Cr(bipyO₂)Cl₂]Cl thin films, were first presented. The sensors exhibited high response to NO₂ gas in the concentration range from 1.97% to 6.67% at relative low temperatures (from room temperature to 348 K). No response to H₂S and SO₂ was observed. The maximum response for 6.03% NO₂ was approximately 11.7 at 338 K and 10 V operating voltage. The response time of the sensors was about 4.5 min for NO₂ and the recovery time about 40 s. The effect of the electrical resistance change of the sensors in the presence of NO₂ could be used for gas sensing measurements. The performance and reliability of the sensors showed their potential applications for monitoring and controlling NO₂ component continuously in chemical production.     

Injection locked single mode operation of a tea CO2 laser with high energy extraction

Generation of reproducible smooth pulses from longitudinal mode control of a TEA CO₂ laser by signal injection from a cw CO₂ laser is reported and the operating conditions investigated for several new geometries. Applied to unstable resonators, the efficient and spectrally pure, high power output obtains has important application in the area of optical pumping.     

Optimal indemnity contracts

Conditions under which policies with deductible provisions, coinsurance provisions, or premium rebates are optimal are given. Results of previous papers on indemnity costs are considered as special cases. For both personal and commercial lines of insurance, further applications consider income taxes, interest income and acquisition costs.     

Submillimeter imaging with a pyroelectric TV camera

The use of a TV camera with a standard pyroelectric tube for imaging continuous submillimeter (submm) waves is described. The spectral sensitivity of such pyroelectric vidicon has been measured. The results of experiments on diffraction and interference using submm laser radiation are presented. For the first time, submm images of different objects have been obtained with the aid of a pyroelectric vidicon. It has been shown that a pyroelectric TV camera can be effectively employed in various laser studies as well as in submm imagery technique.     

Imaging characteristics of toroidal and ellipsoidal mirrors for synchrotron radiation source Indus-1

We discuss and compare the imaging characteristics of toroidal and ellipsoidal mirrors for different horizontal acceptances of synchrotron radiation source Indus-1; using a ray tracing method. It has been shown that the toroidal and ellipsoidal mirrors have similar focussing behaviour at small horizontal acceptances. For large horizontal acceptances, toroidal mirror shows an asymmetry in the focussed image. Though the data used here are for Indus-1, the results are generally valid for any bending magnet synchrotron radiation source incident at grazing angles on these mirrors.     

Si基Bi4Ti3O12铁电薄膜的制备与特性研究

采用sol-gel工艺, 在分层快速退火的工艺条件下成功地制备了高质量Si基Bi_{4Ti3O12铁电薄膜. 研究了Si基Bi4Ti3O12薄膜的生长行为、铁电性能、C-V特性和疲劳特性. 研究表明: Si基Bi4Ti3O12薄膜具有随退火温度升高沿c轴择优生长的趋势; 退火温度通过影响薄膜的晶粒尺寸、生长取向和薄膜中载流子的浓度来改变Si基Bi关键词： sol-gel法 铁电薄膜 4Ti3O12')" href="#">Bi4Ti3O12 C-V特性}     

正三角形及正方形微光学腔模式特性研究

微谐振腔模式特性研究是利用微腔研制新型光电器件的基础．为了研制出能采用平面工艺制作的定向输出的微腔激光器，文章采用解析和数值模拟方法深入研究了正三角形及正方形光学微腔的模式特性，并得到与数值模拟结果符合非常好的解析场分布及模式波长．对正方形光学微腔，把模式组合成满足正方形对称性的场分布，发现其类WG模式只存在品质因子比它小一个数量级以上的偶然简并模式，因此正方形微腔有利于实现真正的单模工作．     

Improved directional couplers for overmoded waveguide systems

The performance of multihole directional couplers can be considerably improved by placing a second hole structure to the existing one. The improvement may be aimed at directivity or at suppression of certain unwanted modes propagating either in forward or backward direction.