非齐次投入产出模型的极限定理（I）

继承了华罗庚先生的工作，提出了和研究了一类消耗系数方阵Ａｎ随时间ｎ变化的，所谓非齐次投入产出模型：Ｚｎ＝Ｚ０Ａ１＾－１Ａ＾－１２．．．Ａ＾－１ｎ其中Ｚ０和Ｚｎ分别是最初年份和第ｎ年的产综，在研究此模型消耗系数方阵序列（Ａｎ）乘积极限性质的基础上，证明了：存在一非负向量子空间Ｅ，若初始产综Ｚ０∈Ｅ则一定存在某个自然数ｎ０，使当ｎ≥ｎ０时，第ｎ年的产综Ｚｎ有负分量，即第ｎ年至少有一个产品部门其产量为负     

Styan不等式的推广

设ｘ为ｎ×１单位向量，Ａ为ｎ×ｎ正交阵，Ｓｔｙａｎ［１］证明了这里λ１和λｎ为Ａ的最大和最小特征值。本文的目的是将上式的ｘ推广为ｎ×ｐ矩阵Ｘ，即证明了，对一切满足Ｘ′Ｘ＝Ｉｐ的矩阵ｘ和正定阵Ａ这里ｎ＞２ｐ，λ１≥…≥λｎ为Ａ的特征值，ｔｒ（Ａ）表示方阵Ａ的迹。     

制备SnO2薄膜时原料中水对其成膜和光电性质的影响

用无水ＳｎＣｌ４和ＳｎＣｌ４．５Ｈ２Ｏ为原料，用热喷涂法制备ＳｎＯ２薄膜，在基片温度为５３０℃时，对所制得ＳｎＯ２薄膜进行了Ｘ－射线，ＳＥＭ分析，并对其发电性质进行测定，总结出含Ｈ２Ｏ的ＳｎＣｌ４制得的ＳｎＯ２薄膜生长速度快，电阻率低。     

非齐次投入产出模型的极限定理（Ⅰ）

继承了华罗庚先生［１］的工作，提出和研究了一类消耗系数方阵Ａｎ随时间ｎ变化的、所谓非齐次投入产出模型：Ｚｎ＝Ｚ０Ａ－１１Ａ－１２…Ａ－１ｎ，其中Ｚ０和Ｚｎ分别是最初年份和第ｎ年的产综。在研究此模型消耗系数方阵序列｛Ａｎ｝乘积极限性质的基础上，证明了：存在一非负向量子空间Ｅｒ，若初始产综Ｚ０Ｅｒ，则一定存在某个自然数ｎ０，使当ｎ≥ｎ０时，第ｎ年的产综Ｚｎ有负分量，即第ｎ年至少有一个产品部门其产量为负值。此说明，若初始产综（实际上可看作是投入产综）不按一定范围的比例投入，那末若干年后，至少会有一个产量部门出现负产量，也即经济系统出现严重失调     

Ti3Sn和Ti3Sn—Nb的电子结构与力学行为

用离散变分Ｘα原子簇方法计算了Ｔｉ３Ｓｎ及加入Ｎｂ后的电子结构，键级（Ｂｏ）和态密度（ＤＯＳ）的分析结果表明：Ｔｉ３Ｓｎ中Ｔｉ－Ｓｎ间相互作用主要是Ｓｎ的Ｓｐ轨道与Ｔｉ的３ｄ，４ｓ，４ｐ轨道的作用，由于在Ｔｉ－Ｓｎ相互作用中ｐ－ｐ作用较强，导致Ｔ１ｅＳｎ的脆性较强，对面和柱面的键级分析结果表明：基面滑移时须破坏较多的近邻Ｔｉ－Ｓｎ键，滑移时需较大的剪切应力，柱面滑移改变的Ｔｉ－Ｓｎ键较少，容易滑移     

自适应声干扰抵消系统

随着视听设备本身的复杂程度日益上升，利用语音进行人机直接对话就越来越变得可能与必要。就语音识别本身而言，目前已能采用一、两片大规模集成电路芯片实现对高信噪比的孤立词的识别。但是当存在干扰与噪声时，其识别准确性将大幅下降。语音系统的输入ｘ（ｎ）由ｓ（ｎ）、ｎ（ｎ）、ｕ（ｎ）三部分组成。其中：ｓ（ｎ）是控制命令语音信号，ｎ（ｎ）是视听设备使用环境中的噪声，一般比较小，可以忽略不计。ｕ（ｎ）来自视听设备，可以将其视作一个已知干扰，因而可以采用声干扰抵消系统抵消其直达声分量以及部分混响声。若利用抵消系统…     

n变元n—1阶相关免疫3值逻辑函数的代数结构

给出了ｎ变元３值逻辑函数为ｎ－１阶相关免疫的充要条件，明确给出了这类函数的代数结构式，且在ｎ〉３时，给出了构造更大一类ｎ变元ｎ－１阶相关免疫平衡ｍ值逻辑函数的方法，最后分析了相关免疫３值逻辑函数的计数问题。     

传热规律对斯特林制冷机性能的影响

导出了斯特林制冷机在传热规律ｑ＝（ＴＲ＾ｎ－ＴＷ＾ｎ）下的最佳制冷系数与制冷率的关系，所得结果包括牛顿定律（ｎ＝１），线性叭象定律（ｎ＝－１）和热辐射定律（ｎ＝４）等条件的最优解。     

MSnO3和MSn0.5Zr0.5O3（M=Sr,Ba）的水热合成

本文利用水热合成方法对ＭＳｎＯ３和ＭＳｎ０．５Ｚｒ０．５（Ｍ＝Ｓｒ，Ｂａ）的合成进行了研究，并采用ＸＲＤ、ＳＥ几ＩＣＰ等进行产物进行了表征，结果表明：在Ｍ（ＯＨ）２．ＳｎＯ２（呈ＳｎＯ２＋ＺｒＯ２）－ＫＯＨ体系中，当ＫＯＨ／Ｓｎ和ＫＯＨ（Ｓｎ＋Ｚｒ）≥３０时，２６０℃下晶化５－７天，可获得ＭＳｎＯ３和ＭＳｎ０．５Ｏ３纯相，在Ｍ（ＯＨ）３－（ＳｎＯ２＋ＺｒＯ３）－ＫＯＨ－Ｈ２Ｏ体系中，可通过控制介质     

钢铁镀Sn扩散处理中镀层组织的形成

根据钢铁试样镀Ｓｎ扩散处理后镀层的显微组织、物相组成及性能等分析，讨论了镀层组织在处理中的形成过程及其原理。试验表明，钢铁试样经镀Ｓｎ扩散处理时，镀层与基体形成一对扩散偶，其结合转变为扩散结合，镀层由ＦｅＳｎ白亮层、白色基底及其上的ＦｅＳｎ晶体与液相间包晶反应生成的ＦｅＳｎ２灰色和黑色暗点以及表面极薄富Ｓｎ合金层组成。     

弹丸在多层复合介质中的爆炸破坏效应研究

根据实验得到的运动弹丸在多层复合介质中不同深度爆炸时产生的弹坑形状、体积及破坏面积，对破坏效应进行了理论分析，建立了弹丸在多层复合介质中的爆炸破坏分区；考虑主要影响破坏效果因素条件下应用量纲分析方法，并结合实验数据得到了破坏参数与比炸深的无量纲关系式和关系曲线，由这些曲线能够方便地查找所需最佳破坏效果对应的比炸深，在相同条件下，该结果可推广到类似目标的爆炸破坏效应分析。     

Analysis of field failure data when modeled Weibull slope increases with time

Weibull time‐to‐fail distributions cannot be correctly estimated from field data when manufacturing populations from different vintages have different failure modes. To investigate the pitfalls of ongoing Weibull parameter estimation, two cases, based upon real events, were analyzed. First, a time‐to‐fail distribution was generated assuming the same Weibull shape parameter representing an increasing failure rate for each monthly batch or vintage of production. The shape parameter was estimated from simulated field data at regular periods as the population accumulated service time. Estimates of the shape parameter were not constant, but gradually decreased (as had occurred in a real system) with added service time. In the second case, field reliability performance was modeled to match the actual historical data for one product from a disk drive manufacturer. The actual data was proprietary and was not directly available for analysis. A production schedule was modeled with a mix of two failure characteristics. The population reaching the field in the first 12 months had a low, constant failure rate. For the second and third years of production, higher volumes were introduced that had the higher, increasing failure rates of the first case. Assessment of the mixed population at each month of calendar time resulted in an increasing Weibull shape parameter estimate at each assessment. When the two populations were separated and estimated properly, a better fit with more accurate estimates of Weibull shape parameters resulted. Copyright © 2010 John Wiley & Sons, Ltd.     

Relationship Between the Solubility Parameter and the Surface Free Energy of Some Solids

Solubility parameters for a number of drugs and related organic solids were determined from their dispersion and polar surface free energy data by means of an equation found to be valid for solvents. The relation fits quite well all solids investigated with an excellent correlation coefficient. The calculated solubility parameters, _O, were checked with the ones estimated from molecular groups and fragment constants according to Fedors method, _F. A similar _O of 14.6 was obtained for o-hydroxybenzoic and p-hgdroxybensoic acids. The deviations from _F shown in ethyl-p-aminobenzoate, benzoic acid, and aspirin were attributed to the imperfection of their vapor.

The solubility profile of hydrocortisone acetate was obtained in dioxane-water mixtures, and the solubility parameter of the drug was determined from the peak solubility in this binary solvent system. The experimental results for some drugs were compared with their solubility parameters calculated from the surface free energy data. Excellent agreement was found for hydrocortisone acetate, whereas griseofulvin and p-hydroxybenzoic agreed fairly. The “chameleonic” behavior of benzoic acid results in different experimental Solubility parameter, and the percentage deviation from _O ranged from 3.4-20.8. A deviation of 11.8% was obtained for ethyl-p-aminobenzoate and was attributed to the influence of its crystal structure which would account for its low _E value measured. The relation suggested was also applied to the dicarboxylic acids. The odd-even alteration seen in their melting points is not reflected on their solubility parameters. The high _O calculated for these acids were related to their elongated shape.     

A Shewhart‐type Control Scheme to Monitor Weibull Data without Subgrouping

This study proposes a Shewhart control scheme to simultaneously monitor the shape parameter and the scale parameter of Weibull data without subgrouping. The proposed control scheme comprises two charts: the X chart and the moving‐ratio (MRa) chart. The X chart plots individual observations to detect the shift of the scale parameter by assuming that the shape parameter is in‐control. In contrast, the MRa chart plots moving ratios, the minimum of two consecutive Weibull data divided by the maximum of them, to detect the shift of the shape parameter. This study models the transition process of the proposed control scheme as a Markov chain to calculate two performance measures: the average number of observations to signal and the average run length. Performance analysis shows that the proposed control scheme is effective in detecting the shift of parameters, especially for the downward shift of the shape parameter. Finally, the implementation of the proposed control scheme is illustrated in two skewed data sets. Copyright © 2013 John Wiley & Sons, Ltd.     

Relationship Between the Solubility Parameter and the Surface Free Energy of Some Solids

Abstract

Solubility parameters for a number of drugs and related organic solids were determined from their dispersion and polar surface free energy data by means of an equation found to be valid for solvents. The relation fits quite well all solids investigated with an excellent correlation coefficient. The calculated solubility parameters, _O, were checked with the ones estimated from molecular groups and fragment constants according to Fedors method, _F. A similar _O of 14.6 was obtained for o-hydroxybenzoic and p-hgdroxybensoic acids. The deviations from _F shown in ethyl-p-aminobenzoate, benzoic acid, and aspirin were attributed to the imperfection of their vapor.

The solubility profile of hydrocortisone acetate was obtained in dioxane-water mixtures, and the solubility parameter of the drug was determined from the peak solubility in this binary solvent system. The experimental results for some drugs were compared with their solubility parameters calculated from the surface free energy data. Excellent agreement was found for hydrocortisone acetate, whereas griseofulvin and p-hydroxybenzoic agreed fairly. The “chameleonic” behavior of benzoic acid results in different experimental Solubility parameter, and the percentage deviation from _O ranged from 3.4-20.8. A deviation of 11.8% was obtained for ethyl-p-aminobenzoate and was attributed to the influence of its crystal structure which would account for its low _E value measured. The relation suggested was also applied to the dicarboxylic acids. The odd-even alteration seen in their melting points is not reflected on their solubility parameters. The high _O calculated for these acids were related to their elongated shape.     

Size- and shape-dependent melting enthalpy and entropy of nanoparticles

A theoretical model free of any adjustable parameter was derived based on the relation between Gibbs energy change and size to describe the size- and shape-dependent behavior of the melting enthalpy and entropy of nanoparticles. For the melting enthalpy and entropy of vanadium (V), silver (Ag), and copper (Cu) nanoparticles, the results of pure theoretical calculation are in good agreement with available molecular dynamic results. The effect of size on the melting enthalpy and entropy of nanoparticles is greater compared to that of shape effect. The melting enthalpy and entropy decrease with particle size decreasing and the smaller the particle size, the greater the size and shape effects. Furthermore, at the same equivalent diameter, the more the shape of nanoparticles deviates from that of the sphere, the smaller the melting enthalpy and entropy. The thermodynamic relations derived herein can quantitatively describe the influence regularities of size and shape on the melting thermodynamic properties of nanoparticles.     

Robust Regression using Probability Plots for Estimating the Weibull Shape Parameter

The Weibull shape parameter is important in reliability estimation as it characterizes the ageing property of the system. Hence, this parameter has to be estimated accurately. This paper presents a study of the efficiency of using robust regression methods over the ordinary least‐squares regression method based on a Weibull probability plot. The emphasis is on the estimation of the shape parameter of the two‐parameter Weibull distribution. Both the case of small data sets with outliers and the case of data sets with multiple‐censoring are considered. Maximum‐likelihood estimation is also compared with linear regression methods. Simulation results show that robust regression is an effective method in reducing bias and it performs well in most cases. Copyright © 2006 John Wiley & Sons, Ltd.     

The Comparative Method for Apparent Density Measurement as a Means of Fine Carbonaceous and Inorganic Porous Material Characterization by the Determination of Shape Coefficient

These investigations are a part of work whose aim is an elaboration of a characterization method for porous fine powders with use of densimetric measurements. Especially, attention to methods of shape coefficient determination was given in this work because many other investigations pointed out that knowledge of this parameter is necessary for such studies. Shape coefficient values were determined with the use of Powers's method (K), the quantitative method (1/L), and the new comparative method (1/k). While densimetric measurements in the characterization of solids are a standard, the comparative method of apparent density determination is applied for the calculation of shape coefficients (1/k). The shape coefficient (1/k) characterizes not a single element of the fine solid but a collection of particles in the bed. The coefficient (1/k) represents the out-of-roundness degree of packed grains in relation to a bed of spheres with the same size distribution as the investigated material.     

Educating local radial basis functions using the highest gradient of interest in three dimensional geometries

We present a novel methodology to effectively localize radial basis function approximation methods in three dimensions. The local scheme requires shape parameter‐dependent functions that can be used to approximate gradients of scattered data and to solve partial differential operators. The optimum shape parameter is obtained from the highest gradient of interest, where a known analytical function, when boundary conditions are not present, or a shape parameter‐free global approximation are used to educate the localized scheme. The later option is applicable to problems where the operator needs to be solved multiple times, like in time evolution or stochastic integration. Past shape parameter's optimizations, for two‐dimensional domains, based on the condition number of the interpolant matrix, were unable to provide satisfactory approximations. The applicability of our method is illustrated in the context of an analytical expression interpolation and during a Ginzburg–Landau relaxation of a free energy functional. In general, the optimum shape parameter depends on geometry, node distribution, and density, whereas the approximation errors decrease as the node density and the local stencil size increase. The effective localization of radial basis functions motivates its use in moving boundary problems and accelerates solutions through sparse matrix solvers. Copyright © 2016 John Wiley & Sons, Ltd.     

Bias correction for the least squares estimator of Weibull shape parameter with complete and censored data

Estimation of the Weibull shape parameter is important in reliability engineering. However, commonly used methods such as the maximum likelihood estimation (MLE) and the least squares estimation (LSE) are known to be biased. Bias correction methods for MLE have been studied in the literature. This paper investigates the methods for bias correction when model parameters are estimated with LSE based on probability plot. Weibull probability plot is very simple and commonly used by practitioners and hence such a study is useful. The bias of the LS shape parameter estimator for multiple censored data is also examined. It is found that the bias can be modeled as the function of the sample size and the censoring level, and is mainly dependent on the latter. A simple bias function is introduced and bias correcting formulas are proposed for both complete and censored data. Simulation results are also presented. The bias correction methods proposed are very easy to use and they can typically reduce the bias of the LSE of the shape parameter to less than half percent.