A multilevel correction method for Stokes eigenvalue problems and its applications

In this paper, a new multilevel correction scheme is proposed to solve Stokes eigenvalue problems by the finite element method. This new scheme contains a series of correction steps, and the accuracy of eigenpair approximation can be improved after each step. In each correction step, we only need to solve a Stokes problem on the corresponding fine finite element space and a Stokes eigenvalue problem on the coarsest finite element space. This correction scheme can improve the efficiency of solving Stokes eigenvalue problems by the finite element method. As applications of this multilevel correction method, a multigrid method and an adaptive finite element technique are introduced for Stokes eigenvalue problems. Some numerical results are given to validate our schemes. Copyright © 2013 John Wiley & Sons, Ltd.     

Controllable Preparation of Hierarchical ZnO Nanocages and its Oxygen Vacancy through the Nanoscale Kirkendall Process

The synthesis of ZnO with tailorable shapes and point defects is important for its potential applications. Here, a facile approach is demonstrated to prepare ZnO nanocages with controllable porous shell structures though sintering a Zn‐based cyanide‐bridged coordination polymer under different temperatures. The transformation of ZnCP microspheres into ZnO nanocages is based on two types of nanoscale Kirkendall effect, which are related to low temperature solid–solid interfacial oxidation and high temperature solid–gas interfacial reaction, respectively. At low temperature (around 300 °C) and before the ZnCP decomposition, the novel “hierarchical ZnO bigger nanocages embedded with smaller nanocages with 10 nm nanocrystals” can be generated. By contrast, when coming to the total decomposition of ZnCP at 800 °C, ZnO nanocages with significantly increased sizes and large cavities are generated, and large amounts of oxygen vacancies (V_O) are created at the same time, leading to the dramatic increased luminescence intensities of the UV peak due to V_O at 540 nm. Thus, the luminescence intensities versus defect concentration in the prepared ZnO nanocages can also be controlled by tuning the sintering temperatures.     

基于小波包和ZFFT的舰船辐射噪声调制特征融合和提取

舰船噪声调制包络谱是水下目标识别的重要特征。本文提出了一种基于小波包分析和ZFFT的高频噪声解调分析(DEMON)方法,对多子带包络谱进行融合,得到了线谱特征明显的DEMON谱;利用倍频算法,对DEMON谱进行了轴频提取。舰船实测数据证明该分析方法的可行性和有效性。     

反重力充填二维流形的显示、观察及分析

本文介绍了反重力充填二维流形的颗粒显示、拍摄和数据测取方法。作为分析实例,给出了充型扩散角随内浇道扩张角变化的实验结果。     

压缩氦原子团簇Hen（n＝3，4，5）排斥势及其多体展开分量计算

 采用Lowdin方法计算了处于压缩状态的氦原子团簇He_n（n＝3，4，5）的排斥势及其多体展开分量。发现随原子数目或压缩度增大，多体展开式的收敛性变差。多体展开式中两体势分量、四体势分量为正值，三体势分量和五体势分量为负值。因此，在进行近似处理时，两体近似法计算的排斥势偏高。经三体修正后的排斥势必然偏低。该计算结果与最新的实验结果定性符合。发现四体势和五体势分量对高密度氦状态方程仍然具有重要贡献。     

高温高密度条件下氢分子间三体与四体相互作用

 为描述高温高密度条件下氢分子间复杂的多体相互作用，以Ree和Bender对两个氢分子间平均作用势的CI计算结果为基础，提出一种可以描述旋转氢分子外域电子云分布的等效氦原子模型。采用该模型所计算的氢分子三体势与CI计算结果符合较好。还对氢分子间四体势进行了计算。     

建立在小波变换基础上的心率变异信号的仿真建模和分解

心率变异性（HeartRateVariability，简记为HRV）是无创检测心脏自主神经调节功能的一种手段，是近年来心电信号处理领域的一个前沿研究热点．考虑到HRV仿真建模的重要性和对HRV信号的1／f成分和非1／f成分分解开，分别处理的必要性，本文建立了基于小波逆变换的HRV信号仿真模型。用该模型仿真的HRV信号不仅包含谐波部分还反映了1／f部分，并且能准确地控制谐波部分的频率。仿真结果表明该模型能较好地仿真出时域、频域特征都接近实际HRV信号的HRV信号．针对1／f过程的特点，本文提出了基于小波变换的方法将HRV信号的1／f成分和非1／f成分在时域上分解开的算法．分解结果表明服这种算法的可行性。     

Production of a Monoclonal Antibody by Simultaneous Immunization of Staphylococcal Enterotoxin A and B

In this paper, a method of simultaneous immunizing BALB/c mice with staphylococcal enterotoxin (SE) A and B (SEA and SEB) to prepare a monoclonal antibody (3F2) for detecting both of SEA and SEB was developed. The results showed that antibody 3F2 had high titers against both SEA and SEB by enzyme-linked immunosorbent assay (ELISA). The sensitivities of 3F2 to SEA and SEB detected by ELISA were 133.2 and 82.5 ng/mL, respectively, and the detection limits for the two enterotoxins were about 1 ng/mL. The antibody 3F2 had high specificities and affinities to both SEA and SEB, and had no cross-reaction with SEC₁, bovine serum albumin, and ovalbumin. SEs-free skimmed milk samples were spiked with different concentrations of SEA, SEB, or both of them, respectively. Average recoveries of SEA and SEB from the spiked samples were all nearly between 82% and 104%. The result suggested that one cell fusion with simultaneous immunization by multiple antigen to prepare monoclonal antibody against them was possible, simple, and economic. The monoclonal antibody could be used in simultaneous detecting multifarious SEs.     

Research of NO2 vertical profiles with look-up table method based on MAX-DOAS

Obtaining the vertical distribution profile of trace gas is of great significance for studying the diffusion procedure of air pollution.In this article,a look-up table method based on multi-axis differential optical absorption spectroscopy(MAX-DOAS)technology is established for retrieving the tropospheric NO₂ vertical distribution profiles.This method retrieves the aerosol extinction profiles with minimum cost function.Then,the aerosol extinction profiles and the atmospheric radiation transfer model(RTM)are employed to establish the look-up table for retrieving the NO₂ vertical column densities(VCDs)and profiles.The measured NO₂ differential slant column densities(DSCDs)are compared with the NO₂ DSCDs simulated by the atmospheric RTM,and the NO₂ VCDs,the weight factor of NO₂ in the boundary layer,and the boundary layer height are obtained by the minimization process.The look-up table is established to retrieve NO₂ VCDs based on MAX-DOAS measurements in Huaibei area,and the results are compared with the data from Copernicus Atmospheric Monitoring Service(CAMS)model.It is found that there are nearly consistent and the correlation coefficient R2 is more than 0.86.The results show that this technology provides a more convenient and accurate retrieval method for the stereoscopic monitoring of atmospheric environment.     

A hybrid algorithm for linearly constrained minimax problems

Many real life problems can be stated as a minimax problem, such as economics, finance, management, engineering and other fields, which demonstrate the importance of having reliable methods to tackle minimax problems. In this paper, an algorithm for linearly constrained minimax problems is presented in which we combine the trust-region methods with the line-search methods and curve-search methods. By means of this hybrid technique, it avoids possibly solving the trust-region subproblems many times, and make better use of the advantages of different methods. Under weaker conditions, the global and superlinear convergence are achieved. Numerical experiments show that the new algorithm is robust and efficient.