紫外线辐照HDPE／PA6共混物界面相互作用的研究

采用ＥＳＣＡ、Ｍｏｌａｕ实验、ＳＥＭ、ＤＳＣ、ＤＭＡ、抽滤分析、ＦＴ－ＩＲ和拉抻应力－应弯曲线，研究了紫外线辐照ＨＤＰＥ／ＰＡ６共混物的界面相互作用机理。结果表明，紫外线辐照下，ＨＤＰＥ分子链上引入Ｃ＝Ｏ、ＣＯＯＨ、－ＯＨ、－ＯＯＨ、－Ｃ－Ｏ－等极性基因；在与ＰＡ６熔融共混过程中， 的Ｃ＝Ｏ、ＣＯＯＨ等基团与ＰＡ６分子我寂的酰胺基或端胺基发生化学反应，生成ＨＤＰＥ－ＰＡ６共聚物。共聚物的形成增强了     

4Cr3Mo2NiVNb热作模具钢等温转变曲线的测定

采用Ｆｏｒｍａｓｔｅｒ－Ｆ热膨胀仪测定了４Ｃｒ３Ｍｏ２ＮｉＶＮｂ热作模具钢等温转变曲线，并与ＨＤ钢进行了对比分析，结果表明，与ＨＤ钢相比，ＨＤ２钢的Ａｃｌ，Ｍｓ下降，Ｃ曲线右移。该现象的产生主要是由合金的价电子结构所引起。     

一个多智能体机器人协作装配系统

介绍了一个基于多智能体概念实现的多机器人协作装配系统——ＭＲＣＡＳ（Ｍｕｌｔｉ－ＲｏｂｏｔＣｏｏｐｅｒａｔｉｖｅＡｓｓｍｂｌｙＳｙｓｔｅｍ）。该系统由组织级计算机、三台工业机器人和一台全方位移动小车（ＯＤＶ）组成，采用分层递阶体系结构。利用ＭＲＣＡＳ系统进行了多机器人协作装配的实验：在ＯＤＶ装配平台上，四台机器人合作装配一个大型桁架式工件。该工件具有多种装配构型，但任何一台机器人不能独立完成装配。     

紫舛线辐照HDPE／PVA短纤维共混物相容性及力学性能的 …

采用接触角测定、ＳＥＭ、抽滤分析和力学性能的测试研究了紫外线辐照ＨＤＰＥ／ＰＶＡ短纤维共混物的力学性能和相容性。结果表明，经紫外线辐照后，由于在分子链上引入了〉Ｃ＝Ｏ、－ＣＯＯＨ、－ＯＨ等极性基团，ＨＤＰＥ与水的接触角度小，亲水性增加。在与ＰＶＡ短纤维共混过程中，ＨＤＰＥ分子链上引入的含氧基团与ＰＶＡ分子链上－ＯＨ基团形成氢键，增强了共混体系相界面相互作用，使共混物的拉伸强度和冲击强度得到了明显提     

紫外线辐照HDPE\PVA短纤维共混物相容性及力学性能的研究

采用接触角测定、ＳＥＭ、抽滤分析和力学性能的测试研究了紫外线辐照ＨＤＰＥ＼ＰＶＡ短纤维共混物的力学性能和相容性。结果表明，经紫外线辐照后，由于在分子链上引入了＞Ｃ＝Ｏ、－ＣＯＯＨ、－ＯＨ等极性基团，ＨＤＰＥ与水的接触角变小，亲水性增加。在与ＰＶＡ短纤维共混过程中，ＨＤＰＥ分子链上引入的含氧基团与ＰＶＡ分子链上－ＯＨ基团形成氢键，增强了共混体系相界面相互作用，使共混物的拉伸强度和冲击强度得到了明显提高。当辐照时间超过１４４ｈ，由于ＨＤＰＥ降解严重，共混物的韧性突降。     

纳米Au团簇在氧化钛修饰的介孔分子筛MCM-41中的组装

以钛酸丁酯为ＴｉＯ_２前驱体,使ＴｉＯ_２均匀分散于纯硅介孔分子筛ＭＣＭ－４１的介孔孔道内表面,利用ＴｉＯ_２光学性质将ＡｕＣｌ－４还原为Ａｕ（０）并组装于氧化钛修饰的ＭＣＭ－４１孔道中．对所合成的Ａｕ负载的氧化钛修饰的ＭＣＭ－４１进行了ＸＲＤ,ＸＰＳ,Ｎ_２吸附－脱附曲线,及固体ＵＶ－Ｖｉｓ漫反射等多种结构表征．由ＸＰＳ谱和固体ＵＶ－Ｖｉｓ漫反射吸收光谱的ｐｌａｓｍｏｎ吸收峰证明Ａｕ团簇呈现０价的金属状态．     

沥青基高比表面积活性碳的物理及化学结构

本文用ＡＳＡＰ２０００吸附仪测定了吸附性能优异的沥青基高比表面积新型活性碳（ＰＨＡＣ）的ＢＥＴ比表面积、用ＢＪＨ和ＤＲＳ法分析了其孔隙结构参数，用ＸＰＳ测定了ＰＨＡＣ的表面元素组成及含氧官能团，对ＰＨＡＣ的表面形态结构进行了ＳＥＭ和ＴＥＭ观察。研究表明：ＰＨＡＣ具有高度发达且均匀的微孔结构，其表面含有一定量的Ｃ－Ｏ－Ｃ、Ｃ－ＯＨ、Ｃ＝Ｏ、Ｏ＝Ｃ－Ｏ等多种类型的含氧官能团。     

CONTENTS OF NEW CARBON MATERIALS OF Vol.16

Ｎｏ .1ＲｅｓｅａｒｃｈａｒｔｉｃｌｅｓＳＴＵＤＹＯＮＴＨＥＭＩＣＲＯＷＡＶＥＡＢＳＯＲＢＩＮＧＰＲＯＰＥＲＴＹＯＦＣＯＭＰＯＳＩＴＥＭＡＴＥＲＩＡＬＣＯＮＴＡＩＮＩＮＧＣＡＲＢＯＮＮＡＮＯＴＵＢＥＳ　ＷＩＴＨＮＩＣＯＡＴＩＮＧＳＨＥＮＺｅｎｇ ｍｉｎ　ＺＨＡＯＤｏｎｇ ｌｉｎ(1) :1………………………………………………………………………ＡＮＥＦＦＥＣＴＩＶＥＭＥＴＨＯＤＦＯＲＰＩＴＣＨＣＯＭＰＯＳＩＴＩＯＮＤＥＳＩＧＮＺＨＩＬｉｎ ｊｉｅ　ＳＯＮＧＪｉｎ ｒｅｎ　ＬＩＵＬａｎｇ(1) :5………………………     

SACD和DVDAudio芯片抢占滩头

ＳＡＣＤ和ＤＶＤＡｕｄｉｏ正在争夺继ＣＤ机之后音频市场的“制空权”,因此比赛正在加紧进行。今年５月份,ＣＩＲＲＵＳＬＯＧＩＣ公司公布了通用ＤＶＤＡｕｄｉｏ解码器集成电路ＣＳ４９３００。该集成电路采用ＣＭＯＳ０－２４μｍ工艺,５Ｖ工作电源;一片电路可实现ＭＬＰ、ＡＣ３、ＤＴＳ、ＭＰＥＧＡｕｄｉｏ解码,并具有与ＨＤＣＤ、ＤｏｌｂｙＶｉｒｔｕａｌ、１９２ｋＨｚ／ＰＣＭ相适应的各项功能。每片价格约１５美元。最近日本ＢｕｒｒＢｒｏｗｎ公司７月份发表了用于ＳＡＣＤ的Ｄ／Ａ变换器ＤＳＤ１７００Ｅ,样品价格约…     

常压MOCVD制备MgO薄膜的研究

本文首次报道用常压金属有机化学气相沉积（ＡＰ－ＭＯＣＶＤ）在Ｓｉ（１００），ＳｉＯ２／Ｓｉ（１００）和Ｐｔ／Ｓｉ（１００）衬底上外延高质量的ＭｇＯ薄膜。研究了衬底温度与薄膜的取向性关系和ＭｇＯ薄膜的潮解特性。高纯ｍａｇｎｅｓｉｕｍａｃｅｔｙｌａｃｅｔｏｎａｔｅ［ｂｉｓ（２，４－ｐｅｎｔａｎｅｔａｎｅ－ｄｉｏｎｏ）ｍａｇｎｅｓｉｕｍ］［Ｍｇ（ＣＨ２ＣＯＣＨ２ＣＯＣＨ３）２］作为金属有机源，扫描电镜（ＳＥＭ），透射电镜（ＴＥＭ）和Ｘ－ＲＡＹ衍射实验显示，在较低的衬底温度（～４８０℃）下一次淀积成单晶膜。薄膜均匀，致密，结晶性和取向性很好，衬底温度（Ｔｓ）在４００℃到６８０℃之间，在Ｓｉ（１００）衬底上生长的ＭｇＯ薄膜都具有［１００］取向，在Ｓｉ（１００）、ＳｉＯ２／Ｓｉ（１００）和Ｐｔ／Ｓｉ（１００）衬底上生长的ＭｇＯ薄膜也都具有［１００］取向。     

装配体的参数化设计研究

通过参数化零件的数据关联分析,并将机械产品的装配模型抽象成两个两件的逐层级联关系,从而对零件模型数据进行装配适应性重构,建立起装配节点上的数据继承、传递和零件驱动关系,实现设计参数和几何模型参数的匹配和连接,从而达到整机产品的参数化设计目的,并以减速箱产品为实例,采用Pro/E系统实现了该装配体的参数化设计.     

一种基于结构动态特性的物理参数识别算法及应用

结合经典数学理论均匀设计和回归分析,借助有限元计算软件和动态测试技术,提出一个简单实用的结构物理参数识别算法,该算法是基于频域法识别物理参数的一种方法。大量的数值计算和工程应用表明,当系统具有良好可重复性和稳定性,待识别参数为一元或二元时,该算法能够有效地解决这类系统中的参数识别问题。利用该算法对某钢桁架结构边界条件中的部分连接刚度进行识别,得到了比较满意的结果,并验证了该算法解决实际问题时的有效性和可行性。     

An Analysis of the Possibilities of Modern Methods of Measuring the Efficiency of Thermoelectric Elements and Their Realization

Modern methods of measuring the efficiency parameter – the basic criterion for estimating the quality of thermoelectric elements – are considered. An analysis of the classical Harman method and its modified version is given as well as of the test method of analyzing the transient characteristic. The last two methods are carried out using the ZRTM measurement system software package. Results of tests of thermoelectric elements are presented in detail.     

An alternate method for determination of brittleness of ceramics and polymers

As opposed to a pendulum scratching test for the determination of brittleness parameter for ceramics and polymers, this paper proposes an alternate brittleness parameter based on indentation analysis. The important advantages are that (i) no elaborate experiments are needed, and (ii) the proposed brittleness parameter has physical implications. The proposed parameter is as effective as the pendulum test for categorizing the brittleness of ceramics and polymers.     

Photoluminescence in amorphous carbon thin films and its relation to the microscopic properties

The photoluminescence properties of amorphous hydrogenated carbon (a-C:H) films grown using a r.f. plasma have been investigated. It is found that the photoluminescence (PL) spectra exhibit a red shift, accompanied by a sharp decrease in PL efficiency and an increase in electron spin density as the applied r.f. power increases. The results can be interpreted by a model in which the a-C:H films consist of two phases with π-bonded clusters embedded in an sp³-bonded amorphous matrix. The excitation and the recombination of electron hole pairs are believed to take place in the π-bonded clusters. As a result of the confinement effect of electron hole pairs in these clusters, the cluster size becomes an important parameter in understanding the PL properties of a-C:H films.     

曲线插值的一种具有还圆性的细分方法

传统的线性四点插值细分方法不能表示圆等非多项式曲线,为了解决这种问题,基于几何特性提出了一种带有一个参数的四点插值型曲线细分方法。细分过程中,过相邻三插值点作圆,过相邻二插值点的圆弧有两个中点,将其加权平均得到新插值点,文中给出了插值公式和算法描述。所给方法具有还圆性,可以实现保凸性。实例分析对比了本方法与多种细分方法的差异,说明本方法是有效的,当参数取值较小时,曲线靠近控制多边形。     

Bayesian Inference and Life Testing Plan for the Weibull Distribution in Presence of Progressive Censoring

This article deals with the Bayesian inference of unknown parameters of the progressively censored Weibull distribution. It is well known that for a Weibull distribution, while computing the Bayes estimates, the continuous conjugate joint prior distribution of the shape and scale parameters does not exist. In this article it is assumed that the shape parameter has a log-concave prior density function, and for the given shape parameter, the scale parameter has a conjugate prior distribution. As expected, when the shape parameter is unknown, the closed-form expressions of the Bayes estimators cannot be obtained. We use Lindley's approximation to compute the Bayes estimates and the Gibbs sampling procedure to calculate the credible intervals. For given priors, we also provide a methodology to compare two different censoring schemes and thus find the optimal Bayesian censoring scheme. Monte Carlo simulations are performed to observe the behavior of the proposed methods, and a data analysis is onducted for illustrative purposes.     

A model for Bayesian software reliability analysis

Two problems which are of great interest in relation to software reliability are the prediction of future times to failure and the calculation of the optimal release time. An important assumption in software reliability analysis is that the reliability grows whenever bugs are found and removed. In this paper we present a model for software reliability analysis using the Bayesian statistical approach in order to incorporate in the analysis prior assumptions such as the (decreasing) ordering in the assumed constant failure rates of prescribed intervals. We use as prior model the product of gamma functions for each pair of subsequent interval constant failure rates, considering as the location parameter of the first interval the failure rate of the following interval. In this way we include the failure rate ordering information. Using this approach sequentially, we predict the time to failure for the next failure using the previous information obtained. Using also the relevant predictive distributions obtained, we calculate the optimal release time for two different requirements of interest: (a) the probability of an in‐service failure in a prescribed time t; (b) the cost associated with a single or more failures in a prescribed time t. Finally a numerical example is presented. Copyright © 2000 John Wiley & Sons, Ltd.     

Perfluorosulfonated ionomer-modified diffusive gradients in thin films: tool for inorganic arsenic speciation analysis

A new concept in speciation analysis based on the diffusive gradients in thin films (DGT) technique is described. By use of two sets of DGT devices, one set with perfluorosulfonated ionomer (Nafion) diffusive membranes and the other with polyacrylamide, anionic and uncharged analytes can be fractionated on the basis of charge. The dual device method is applied to speciation analysis of dissolved inorganic arsenic species. Over the environmentally significant pH range, inorganic As(III) exists as neutral H(3)AsO(3), whereas As(V) is present as anionic H(2)AsO(4)(-) and HAsO(4)(2-). The measured diffusion coefficient of As(III) through the negatively charged Nafion membrane is significantly larger than that of the As(V) species, whereas diffusion rates are similar through polyacrylamide diffusive gels. Hence, after simultaneously deploying DGT devices with and without Nafion membranes, measurement of the amount of accumulated As in each type of device enables the concentration of both oxidation states to be determined.     

大型空间环模器热沉仿真研究

用分布参数方法，建立了热沉动态数学模型，运用MATRIXx仿真平台，建立了仿真模型，并进行了动，静态工况仿真计算。得出了热沉在稳定工况下的温度场，流量与最大温差的关系及温度动态特性，为热沉的优化设计，温度控制提供了重要依据，也为调温系统的动态仿真奠定了基础。