Isotope dilution analysis of selenite and selenate in natural water using microwave-induced nitrogen plasma mass spectrometry.

Isotope dilution analysis of the sub-microg l(-1) levels of selenite and selenate in natural water samples by microwave-induced nitrogen plasma mass spectrometry (MIP-MS) was performed. An appropriate amount of a spike solution containing 78Se-selenite and 78Se-selenate was added to the natural water sample to be analyzed. Both analytes in the water were then concentrated simultaneously by passing the sample through a column that was filled with an anionic exchange resin. After the concentration process, all of the selenite and some of the selenate on the resin were eluted by 0.03 M nitric acid. The residual selenate was eluted by 0.13 M nitric acid. The eluted sample solutions were injected into MIP-MS, and isotope dilution analyses were carried out. Selenite and selenate concentrations as low as 0.01 microg l(-1) in the natural water sample were successfully determined by the proposed method.     

An effective method for coupling single-mode fiber to thin-filmwaveguide

An effective method for coupling optical signals from single-mode fibers to thin-film waveguides is proposed. The authors show that this method provides high coupling efficiency for connecting fibers of different core diameters to thin-film waveguides of different film thicknesses or refractive indexes. The authors summarize the theoretical treatment of the coupler. Examples of couplers designed for SiO₂ -based materials as well as iron garnets are presented. Fabrication of the proposed coupler and its experimental results are described     

The measurement of penetration depth and surface resistance of bulk YBCO superconductor by using microstrip resonator method

We have measured the resonance curves of a high Tc superconducting microstrip resonator at both room temperature and liquid nitrogen temperature, and done same thing to a copper microstrip resonator with the same width and length as high Tc superconducting microstrip resonator. These four curves have been compared with each other. After that we obtained the penetration depth and surface resistance of high Tc superconductor at liquid nitrogen temperature. The microstrip resonator method has the advantage of simple. The results agree with theoretical prediction and other papers quite well.     

A comparison of some domain decomposition and ILU preconditioned iterative methods for nonsymmetric elliptic problems

In recent years, competitive domain-decomposed preconditioned iterative techniques of Krylov-Schwarz type have been developed for nonsymmetric linear elliptic systems. Such systems arise when convection-diffusion-reaction problems from computational fluid dynamics or heat and mass transfer are linearized for iterative solution. Through domain decomposition, a large problem is divided into many smaller problems whose requirements for coordination can be controlled to allow effective solution on parallel machines. A central question is how to choose these small problems and how to arrange the order of their solution. Different specifications of decomposition and solution order lead to a plethora of algorithms possessing complementary advantages and disadvantages. In this report we compare several methods, including the additive Schwarz algorithm, the classical multiplicative Schwarz algorithm, an accelerated multiplicative Schwarz algorithm, the tile algorithm, the CGK algorithm, the CSPD algorithm, and also the popular global ILU-family of preconditioners, on some nonsymmetric or indefinite elliptic model problems discretized by finite difference methods. The preconditioned problems are solved by the unrestarted GMRES method. A version of the accelerated multiplicative Schwarz method is a consistently good performer.     

k维布朗运动C-R型增量在Hlder范数下的泛函极限定理

本文在Ｈ ｌｄｅｒ范数生成的强拓扑下，　通过建立大偏差公式，　得到了ｋ维布朗运动Ｃ－Ｒ型增量在Ｈ ｌｄｅｒ范数下的泛函极限定理．     

涉及导函数的亚纯函数的唯一性

本文研究亚纯函数f与f＇具有两个公共值时的Frank问题,证明了若f与f＇以0为CM公共值,以有穷非零复数b为IM公共值,则f=f＇或f=2b/1-ce-2z,其中c为任一有穷非零复数.     

光刻用有机金浆研究

光刻有机金浆是以金的树脂酸盐为主，配以有关的贵、贱金属的树脂酸盐等制成。这种浆料分散性好，纯度高，烧制成的金膜薄而致密，覆盖率高，光刻出的图形边沿整齐，分辨率高，附着力好，可以制作出较精密的线路，对于厚薄膜难于满足的一些性能得到了实现和提高。对我国电子工业发展将会起到一定的积极作用。     

On Selecting k Balls from an N-circle Without Unit Separation

Ｏｎ　Ｓｅｌｅｃｔｉｎｇ　ｋ　Ｂａｌｌｓ　ｆｒｏｍ　ａｎ　Ｎ－ｃｉｒｃｌｅ　Ｗｉｔｈｏｕｔ　Ｕｎｉｔ　ＳｅｐａｒａｔｉｏｎＣａｉＴｉａｎｘｉｎ（蔡天新）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｃｍａｔｉｃｓ，ＨａｎｇｚｈｏｎＵｎｉｖｅｒｓｉｔｙ，Ｈａｎｇｚ...     

On the Residues of Binomial Coefficients and Their Products Modulo Prime Powers

In this paper, we show several arithmetic properties on the residues of binomial coefficients and their products modulo prime powers, e.g., for any distinct odd primes p and q. Meanwhile, we discuss the connections with the prime recognitions. Received November 5, 1998, Accepted December 7, 2000.     

Si离子注入和退火温度对GaN黄光的影响

对光致发光谱中无黄光和有强黄光的两组GaN样品作了Si离子注入 ,研究了Si离子注入及退火温度对其黄光的影响 .当退火温度升高时 ,不管是哪一组样品 ,其黄光强度和黄光强度与带边发光带强度之比都是增强的 .无黄光的GaN样品在注入Si离子并经退火后出现明显的黄光 ;而有强黄光的GaN样品经相同处理后 ,其黄光强度较原生样品大大降低 .实验结果表明离子注入加上适当退火会在GaN中引入与黄光有关的深受主缺陷从而使黄光强度增加 ,此外 ,在离子注入过程中GaN表面不仅可以吸附离子注入引入的点缺陷 ,而且还能够吸附GaN中原有的与黄光有关的点缺陷 ,这种吸附作用随离子注入剂量增加而变强 .