Investigation of Resistivity of Saturated Porous Media with Lattice Boltzmann Method

The lattice Boltzmann method is employed to study the electrical transport properties of saturated porous media.Electrical current flow through the porous media is simulated and the relationship between resistivity index and water saturation is derived. It is found that this kind of relation is not a straight line as described by the Archie equation with the parameter n being a constant in a log-log scale. A new equation is thus developed to formulate this relation with n being a function of porosity and water saturation. The comparisons between the results by lattice Boltzmann and by the laboratory experiments on rock samples demonstrate that this numerical method can provide an alternative way for the expensive laboratory experiments to investigate the electrical transport properties of saturated porous media and can be used to explore micro mechanisms more conveniently.     

A PATTERN RECOGNITION APPROACH FOR TONE CLASSIFICATION OF ISOLATED SYLLABLE IN PUTONGHUA

In this paper,a new approach of pattern recognition for tone classification of Putonghua Which is im-portant for speech recognition of Putonghua is discribed.In this method,four parameters of the fundamen-tal frequency trajectory are selected based on a large number of statistical experiments.It is assumed thatthe four parameters satisfy multidimensional Gaussion distribution and a non-Euclidean distancefunction for each tone class is derived according to the rule of minimum probability of calssification error.the optimal decision results are obtained in a sense of statistics.It is proved that this method provides verysatisfactory results by the experiments for speaker-independent tone classification of Putonghua.     

Quality evaluation of phase reconstruction in LED-based digital holography

An approach, based on the correlation between the intensity distribution of object wave of the directly recorded by charge-coupled device and the one reconstructed by computer, is proposed to evaluate the quality of the phase reconstruction in light emitting diode （LED） based phase-shifting digital holography. This method enables us to find out the optimal reconstructed phase even though the peak wavelength of LED, which is used for calibrating the phase-shifter, is inconvenient to be determined and tends to shift with temperature and driving current. The feasibility of this method is verified by both computer simulations and experiments.     

Mechanism of Explosive Technique on Relieving Welding Residual Stresses

The complex physical process of welding residual stress relieving by means of explosive technique is studied experimentally and numerically. The experiments are carried out in welded 16 MnR steel plates. In the numerical simulations, the explicit dynamic finite element method is adopted. The results from experiments and computations are consistent with each other. The mechanism of this technique is explained by considering the effect of stress wave reflection and superposition on the redistribution of stresses in this process. Based on the above studies, some advises and parameters are provided to practical applications of this technique.     

Performance improvement for optical packet switch with shared buffers

In this paper, an inner wavelength method is proposed to enlarge buffering capacity of shared fiber delay line buffers. In addition, an optical packet switch called extended shared buffer type optical packet switch(extended SB-OPS) is proposed to realize the inner wavelength method. In order to further improve performance of extended SB-OPS, a greedy algorithm based on inner wavelength method is introduced.The performance of extended SB-OPS is evaluated by simulation experiments.     

Performance improvement for optical packet switch with shared buffers

In this paper, an inner wavelength method is proposed to enlarge buffering capacity of shared fiber delay line buffers. In addition, an optical packet switch called extended shared buffer type optical packet switch (extended SB-OPS) is proposed to realize the inner wavelength method. In order to further improve performance of extended SB-OPS, a greedy algorithm based on inner wavelength method is introduced. The performance of extended SB-OPS is evaluated by simulation experiments.     

Natural color image segmentation using integrated mechanism

A new method for natural color image segmentation using integrated mechanism is proposed in this paper. Edges are first detected in term of the high phase congruency in the gray-level image. K-mean cluster is used to label long edge lines based on the global color information to estimate roughly the distribution of objects in the image, while short ones are merged based on their positions and local color differences to eliminate the negative affection caused by texture or other trivial features in image. Region growing technique is employed to achieve final segmentation results. The proposed method unifies edges, whole and local color distributions, as well as spatial information to solve the natural image segmentation problem. The feasibility and effectiveness of this method have been demonstrated by various experiments.     

Speech recognition based on a combination of acousticfeatures with articulatory information

The contributions of the static and dynamic articulatory information to speech recognition were evaluated, and the recognition approaches by combining the articulatory information with acoustic features were discussed. Articulatory movements were observed by the Electromagnetic Articulographic System for reading speech, and the speech signals were recorded simultaneously. First, we conducted several speech recognition experiments by using articulatory features alone, consisting of a number of specific articulatory channels, to evaluate the contribution of each observation point on articulators. Then, the displacement information of articulatory data were combined with acoustic features directly and adopted in speech recognition. The results show that articulatory information provides with additional information for speech recognition which is not encoded in acoustic features. Furthermore, the contribution of the dynamic information of the articulatory data was evaluated by combining them in speech recognition. It is found that the second derivative of articulatory information provided quite larger contribution to speech recognition comparing with the second derivative of acoustical information. At last, the combination methods of articulatory features and acoustic ones were investigated for speech recognition. The basic approach is that the Bayesian Network (BN) is added to each state of HMM, where the articulatory information is represented by the BN as a factor of observed signals during training the model and is marginalized as a hidden variable in recognition stage. Results based on this HMM/BN framework show a better performance than the traditional method.     

An element-free Galerkin （EFG） method for numerical solution of the coupled Schrodinger-KdV equations

The present paper deals with the numerical solution of the coupled Schrodinger-KdV equations using the elementfree Galerkin （EFG） method which is based on the moving least-square approximation. Instead of traditional mesh oriented methods such as the finite difference method （FDM） and the finite element method （FEM）, this method needs only scattered nodes in the domain. For this scheme, a variational method is used to obtain discrete equations and the essential boundary conditions are enforced by the penalty method. In numerical experiments, the results are presented and compared with the findings of the finite element method, the radial basis functions method, and an analytical solution to confirm the good accuracy of the presented scheme.     

An element-free Galerkin(EFG) method for numerical solution of the coupled Schrdinger-KdV equations

The present paper deals with the numerical solution of the coupled Schrdinger-KdV equations using the elementfree Galerkin(EFG) method which is based on the moving least-square approximation.Instead of traditional mesh oriented methods such as the finite difference method(FDM) and the finite element method(FEM),this method needs only scattered nodes in the domain.For this scheme,a variational method is used to obtain discrete equations and the essential boundary conditions are enforced by the penalty method.In numerical experiments,the results are presented and compared with the findings of the finite element method,the radial basis functions method,and an analytical solution to confirm the good accuracy of the presented scheme.     

Extraction of isotropic points using simulated isoclinics obtained by photoelasticity-assisted finite element analysis

A method for extracting isotropic points in structures using simulated isoclinics obtained from a combination of photoelastic experiments and finite element analysis (FEA) is presented. This method is divided into two parts. The first part involves the confirmation of the boundary condition necessary for FEA using isochromatics obtained by photoelastic experiments. The second part involves the determination of isotropic points using simulated isoclinics obtained by FEA under the boundary condition confirmed by photoelastic experiments. This method is applied to a ring and T-shaped plates subjected to a compressive load. The results show that the isotropic points in the ring and T-shaped plates could be accurately and easily extracted by this method.     

一个获得压水峰良好效果的简单方法

蛋白质NMR中最基本的实验是HSQC实验．在HSQC实验中,水峰压制的主要方法之一是利用一对与异核旋磁比比值相适应的梯度脉冲．该文介绍一种简单易行的方法,只需对这一对脉冲进行适当的延长便能使得水峰几乎完全消失.     

基于光谱信息的空间目标模式识别算法研究

在观测空间目标时,往往会受到地基观测仪器等因素的制约,导致无法利用目标图像信息从外形上进行识别。根据不同空间目标表面组成材料不同,其产生的反射光谱会存在差异这一特性,可利用空间目标特有的光谱信息进行识别分类。基于此,从光谱学角度对空间目标识别算法进行研究,在K最近邻算法(KNN)的基础上,采用了一种自适应权重局部超平面方法(AWKH),算法主要在计算预测样本与超平面距离时加入对特征权重的考虑,构建了以样本特征组间差与组内差的比值作为特征权重值的超平面模型,从而提高了分类效果和分类效率。为验证算法的分类效果,本文进行了四组验证实验,第一组实验将美国地质勘探局数据库中提取出的九种常用材料光谱随机选出三种混合成多类进行识别;第二、三组实验将四种常用空间目标材料的光谱作为纯物质光谱,分别从可见光和近红外波段对其混合物质进行分类;第四组实验通过实测四个方形模型样本六个面的光谱对其进行识别分类。实验过程中将实验结果与目前常用的支持向量机(SVM)进行对比,对比结果表明改进后的AWKH算法在识别精度和样本适用范围上具有更高的优越性。     

间歇性正比于系统变量方法控制超混沌的实验

利用电子电路和PSPICE软件实现了间歇性正比于系统变量方法控制超混沌的实验，在实验中进一步拓展间歇性正比于系统变量方法，用一个微扰反馈信号作用到系统的其它变量，得到了较好的控制效果。     

Feasibility study of online tuning of the luminosity in a circular collider with the robust conjugate direction search method

The robust conjugate direction search(RCDS) method has high tolerance to noise in beam experiments.It has been demonstrated that this method can be used to optimize the machine performance of a light source online.In our study,taking BEPCII as an example,the feasibility of online tuning of the luminosity in a circular collider is explored,through numerical simulation and preliminary online experiments.It is shown that the luminosity that is artificially decreased by a deviation of beam orbital offset from optimal trajectory can be recovered with this method.     

激光聚变靶设计中参数不确定性指标的线性近似法

激光聚变的点火对实验、器件、制靶及诊断等各方面的控制能力都有很高的要求。随着实验逐步趋近点火设计, 实验的精密化要求也逐步提高。精密化实验要求靶设计不仅给出激光能量、靶尺寸、气压等参数, 还需要给出这些关键参数的不确定性指标要求。因此, 获得这些不确定性指标也成为靶设计的主要内容之一。针对如何在实验设计中更为方便有效地获得参数的不确定性指标问题, 通过理论结合数值模拟研究给出了一种基于线性近似的方法。这一方法综合考虑各种关键参数变化对实验结果的影响, 平衡器件、制靶等对各种参数的控制能力, 来获得参数的不确定性指标。以一个气体靶设计为例, 通过数值模拟来展示这种方法的使用。结果表明, 这一方法可以在显著降低工作量的情况下有效地获得实验设计的参数不确定性指标。     

差分吸收光谱法监测NO2浓度技术研究

差分吸收光谱(DOAS)是利用气体分子对光谱具有特殊吸收这一特性来测量气体浓度的一种测量技术.本文介绍了DOAS法的基本测量原理,分析了DOAS的数据处理方法,并用DOAS法进行了不同情况时NO2气体浓度测量的实验研究.     

Elastic constants of the SrLaAlO4 and SrLrGagaO4 crystals measured at ultrasonic and hypersonic oustic frequencies

Elastic constants measured by Brillouin light-scattering experiments were compared with results estimated from the pulse-echo-overlap method for the ultrasonic frequency to find dispersion in their values. In this way Brillouin hypersonic experiments complete the ultrasonic results. The present investigation includes a careful analysis of the accuracy of the results. The measured values of elastic constants suggest a weak dispersion in acoustic wave velocities. However, given the magnitude of the experimental errors, it is difficult to conclude about the dispersion.     

Schlieren method and its application for plasma diagnostics

In recent years experiments were done with the application of the schlieren method for measuring electronic and atomic density gradients in plasma. The method proved to be useful. The aim of this paper is to point out the advantages of this rarely used optical method. The principle, characteristic and application of the mentioned method in plasma physics are described.     

激光激发荧光谱的双光路多道分析方法研究

使用双光路相关方法有效的克服了激光激发荧光谱分析中激发激光波动对荧光光谱分析的影响 ,显著降低了分析误差。在对若丹明 6G荧光和对十二烷基硫酸钠 (SDS)对R6G的荧光增强的测量中 ,相关系数大于 0 9。和采样平均法比较表明 ,在激发光波动较大时 ,此方法有明显优势。