强激光远场焦斑重构算法研究

 通过CCD图像采集单元结合传统的列阵相机测量高功率固体激光器的远场焦斑分布，采用图像处理技术的边缘算子提取焦斑的几何中心，提出通过几何中心对心的焦斑嵌套重构算法，解决了光斑饱和时的对心难题，实现了快捷准确测量激光焦斑，为激光器的实时控制提供参考数据。     

Irregularities of distribution with respect to strips

Summary A lower bound is established for the strip discrepancy of a broad class of point distributions. The bound implies unbounded strip discrepancy for equally weighted point distributions under favorable conditions. The methods of proof use notions from integral geometry.     

Making Use of Incomplete Observations for Regression in Bivariate Normal Model

Two estimates of the regression coefficient in bivariate normal distribution are considered: the usual one based on a sample and a new one making use of additional observations of one of the variables. They are compared with respect to variance. The same is done for two regression lines. The conclusion is that the additional observations are worth using only when the sample is very small.     

Pore formation during the pyrolysis of C-Nb2O5 and C-Ta2O5 xerogels

Binary organic-inorganic gels have been prepared by mixing a carbonaceous hydrosol and a Nb₂O₅ or Ta₂O₅ sol derived by hydrolysis of the alkoxides. The gels are pyrolyzed under an inert atmosphere into precursors in which carbon and the metal oxides are mixed very intimately. High temperature treatment converts the precursors into the cubic face centered carbides. The precursors as well as the carbides have been shown to be micro- and mesoporous materials. Measurements of nitrogen adsorption reveal a characteristic change of the shapes of the isotherms (Type I Type IV) and of the hysteresis loops (H4H2H1) during the thermal processes. Pore widening has been observed with rising temperature. The phenomena of crystallization, carbothermal reduction and sintering were found to control the pore shape and size. The results of the adsorption measurement correlate well with those of the thermoanalytical and X-ray diffraction studies.Dedicated to Professor Dr. rer.nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday     

Continuous approximation schemes for stochastic programs

One of the main methods for solving stochastic programs is approximation by discretizing the probability distribution. However, discretization may lose differentiability of expectational functionals. The complexity of discrete approximation schemes also increases exponentially as the dimension of the random vector increases. On the other hand, stochastic methods can solve stochastic programs with larger dimensions but their convergence is in the sense of probability one. In this paper, we study the differentiability property of stochastic two-stage programs and discuss continuous approximation methods for stochastic programs. We present several ways to calculate and estimate this derivative. We then design several continuous approximation schemes and study their convergence behavior and implementation. The methods include several types of truncation approximation, lower dimensional approximation and limited basis approximation.His work is supported by Office of Naval Research Grant N0014-86-K-0628 and the National Science Foundation under Grant ECS-8815101 and DDM-9215921.His work is supported by the Australian Research Council.     

Corrigendum to a Paper by Charak and Laine

This is a corrigendum to our paper, "On a class of prime entire functions", published in Acta Math. Sin., Engl. Ser., 25, 1647-1652 (2009).     

Integrated Groups and Smooth Distribution Groups

In this paper, we prove directly that α-times integrated groups define algebra homomorphisms. We also give a theorem of equivalence between smooth distribution groups and α-times integrated groups.     

Error bounds for asymptotic expansions of the distribution of the MLE in a GMANOVA model

Summary In this paper we obtain asymptotic expansions for the distribution function and the density function of a linear combination of the MLE in a GMANOVA model, and for the density function of the MLE itself. We also obtain certain error bounds for the asymptotic expansions.     

Approximation of the Posterior Distribution in a Change-Point Problem

We consider a family of models that arise in connection with sharp change in hazard rate corresponding to high initial hazard rate dropping to a more stable or slowly changing rate at an unknown change-point . Although the Bayes estimates are well behaved and are asymptotically efficient, it is difficult to compute them as the posterior distributions are generally very complicated. We obtain a simple first order asymptotic approximation to the posterior distribution of . The accuracy of the approximation is judged through simulation. The approximation performs quite well. Our method is also applied to analyze a real data set.     

Determination of various inorganic anions and organic acids in the atmospheric particulate matter using capillary zone electrophoresis with indirect UV detection

Capillary zone electrophoresis with indirect UV detection was developed for the simultaneous analysis of inorganic anions and organic acids using a mixed solution of 2,6-pyridinedicarboxylic acid and cetyltrimethylammonium hydroxide as the background electrolyte (BGE). The parameters which influence the separation, such as indirect UV detection wavelength, BGE conditions, applied voltage and extraction conditions were investigated. Thirteen inorganic anions and organic acids were detected within 20 min. The calibration curves of each analyte were linear with correlation coefficients greater than 0.991. The relative standard deviations (n = 10) of the peak areas ranged from 0.6% to 3.3%. The detection limits for these species ranged from 0.4 to 1.4 mg/L at a signal-to-noise ratio of 3. The recovery rate of each analyte was more than 80% under optimised extraction conditions, except for nitrite. The proposed method was applied towards the analysis of inorganic anions and organic acids in the atmospheric particulate matter using an Andersen sampler. The particle size of the particulate matter was determined, but not the size of the anions.