高层结构几何非线性分析的QR法

本文利用ＱＲ法分析高层建筑结构几何非线性问题，建立了新的计算格式。该法不仅未知量的数目少，精度高，而且输入简单，计算速度快，可以用微机分析复杂问题。     

粒界缓冲型展宽效应对PTC材料温度系数的影响

本文利用相变扩张理论分析了粒界缓冲型展宽效应对BaTiO_3系PTC陶瓷的介电系数及温度系数a_r的影响,指出了晶粒尺寸和温度系数的关系。     

一种新颖的跳频振荡器

摘要本文综合考虑到频率合成技术及单端口体波谐振器HBAR的特点提出了一种基于一阶非线性PLL的锁相频率合成方案。文中对这种跳频方案的原理、性能特点作了详细论述、并通过实验、从不同角度对本方案进行了说明、同时对整机的各项指标作了详尽测试:在HBAR无载Q_N值为4000的情况下,该多模跳频振荡源的捷变范围为770MHz—840MHz、捷变时间小于20μS。杂散分量低于—60dB、二次谐波分量低于—34dB。离散捷变频率点为16点,构成闭环跳频系统后,对开环VCO的短稳改善了三个量级:从1.3×10~(-5)/ms到1.6×10~(-8)/ms及9.56×~(-7)/s到1.69×!0~(-9)/s,尤为重要的是该多模跳频振荡源达到此性能所需的硬件量很小,因此在对体积要求苛刻的场合、此种跳频方案具有极强的竞争力。     

Criteria of dynamic buckling estimation of thin-walled structures

The paper deals with dynamic buckling of thin-walled structures (plates and beam-columns with open cross-section) subjected to compressive rectangular pulse loading. The local, global and interactive dynamic buckling was analysed. Author proposes the new criterion for critical amplitude of pulse loading leading to stability loss. The proposed criterion is a modification of quasi-bifurcation criterion formulated by Kleiber, Kotula and Saran. Results obtained using proposed criterion were compared with other well-known criteria (Volmir (V) and Budiansky–Hutchinson (B–H) criterion).     

Nonlinear black-box modeling in system identification: a unified overview

A nonlinear black-box structure for a dynamical system is a model structure that is prepared to describe virtually any nonlinear dynamics. There has been considerable recent interest in this area, with structures based on neural networks, radial basis networks, wavelet networks and hinging hyperplanes, as well as wavelet-transform-based methods and models based on fuzzy sets and fuzzy rules. This paper describes all these approaches in a common framework, from a user's perspective. It focuses on what are the common features in the different approaches, the choices that have to be made and what considerations are relevant for a successful system-identification application of these techniques. It is pointed out that the nonlinear structures can be seen as a concatenation of a mapping form observed data to a regression vector and a nonlinear mapping from the regressor space to the output space. These mappings are discussed separately. The latter mapping is usually formed as a basis function expansion. The basis functions are typically formed from one simple scalar function, which is modified in terms of scale and location. The expansion from the scalar argument to the regressor space is achieved by a radial- or a ridge-type approach. Basic techniques for estimating the parameters in the structures are criterion minimization, as well as two-step procedures, where first the relevant basis functions are determined, using data, and then a linear least-squares step to determine the coordinates of the function approximation. A particular problem is to deal with the large number of potentially necessary parameters. This is handled by making the number of ‘used’ parameters considerably less than the number of ‘offered’ parameters, by regularization, shrinking, pruning or regressor selection.     

InGaAsP／InP PFBH激光器

采用Ｎ－ＩｎＰ衬底研制ＩｎＧａＡｓＰ／ＩｎＰ激光器和ＤＦＢ激光器在国内已报导过多次，本文介绍用Ｐ－ＩｎＰ衬底研制ＩｎＧａＡｓＰ／ＩｎＰ平面埋层异质结构激光器和ＤＦＢ－ＰＦＢＨ激光器，同时利用晶体生长和晶向的依赖关系，改进埋区的结构，使器件最高激射温度大于１００℃。     

Tree-based partitioning of date for association rule mining

The most computationally demanding aspect of Association Rule Mining is the identification and counting of support of the frequent sets of items that occur together sufficiently often to be the basis of potentially interesting rules. The task increases in difficulty with the scale of the data and also with its density. The greatest challenge is posed by data that is too large to be contained in primary memory, especially when high data density and/or low support thresholds give rise to very large numbers of candidates that must be counted. In this paper, we consider strategies for partitioning the data to deal effectively with such cases. We describe a partitioning approach which organises the data into tree structures that can be processed independently. We present experimental results that show the method scales well for increasing dimensions of data and performs significantly better than alternatives, especially when dealing with dense data and low support thresholds. Shakil Ahmed received a first class BSc (Hons) degree from Dhaka University, Bangladesh, in 1990; and an MSc (first class), also Dhaka University, in 1992. He received his PhD from The University of Liverpool, UK, in 2005. From 2000 onwards he is a member of the Data Mining Group at the Department of Computer Science of the University of Liverpool, UK. His research interests include data mining, Association Rule Mining and pattern recognition. Frans Coenen has been working in the field of Data Mining for many years and has written widely on the subject. He received his PhD from Liverpool Polytechnic in 1989, after which he took up a post as a RA within the Department of Computer Science at the University of Liverpool. In 1997, he took up a lecturing post within the same department. His current Data Mining research interests include Association rule Mining, Classification algorithms and text mining. He is on the programme committee for ICDM'05 and was the chair for the UK KDD symposium (UKKDD'05). Paul Leng is professor of e-Learning at the University of Liverpool and director of the e-Learning Unit, which is responsible for overseeing the University's online degree programmes, leading to degrees of MSc in IT and MBA. Along with e-Learning, his main research interests are in Data Mining, especially in methods of discovering Association Rules. In collaboration with Frans Coenen, he has developed efficient new algorithms for finding frequent sets and is exploring applications in text mining and classification.     

Equilibrium distribution of water in the two-phase system supercritical carbon dioxide–textile

When natural fibres are dyed in supercritical carbon dioxide, the addition of a small amount of water increases coloration. For a process design it is important to know how much water has to be added to obtain a desired humidity of both textile and carbon dioxide. In this work a thermodynamic model is proposed to calculate the distribution of water over the textile phase and the supercritical phase as a function of pressure and temperature. The phase equilibrium is described with Raoult's law for non-ideal fluids. The absorbed water in the textile is a condensed phase and is modelled here as a non-ideal liquid, using the NRTL-equation. The non-ideality of the supercritical phase is described by a solubility enhancement factor, a new equation derived from statistical thermodynamics. Although the model is applied to cotton, viscose, silk and wool, it can be used for all water absorbing textiles.     

电流控制LPE生长In_（1－x）Ga_xAs_yP_（1－Y）

用电流控制液相外延（ＣＣＬＰＥ）方法首次在（１００）ＩｎＰ衬底上成功地生长出Ｉｎ１－ｘＧａｘＡｓｙＰ１－ｙ（０．３０＜ｘ＜０．４７，０．７０＜ｙ＜０．９６）外延层，并对外延层特性进行了详细研究，提出在ＩｎＰ衬底上生长电外延层的机理，推导出生长动力学的理论模型，该模型与上述实验结果十分吻合。     

TiO_2对ZrO_2－NiCr金属陶瓷烧结特性和相稳定性的影响

本文研究了ＴｉＯ２掺入对ＣａＯ稳定ＺｒＯ２（简称ＣａＳＺ－ＮｉＣｒ）金属陶瓷烧结特性的影响，测定了ＣａＳＺ－ＮｉＣｒ－ＴｉＯ２金属陶瓷烧结样品的密度和显微硬度，结果表明，ＴｉＯ２的掺入能提高ＣａＳＺ－ＮＩＣｒ金属陶瓷的烧结密度和显微硬度，对ＣａＳＺ－ＮｉＣｒ金属陶瓷有助烧结作用．金相观察表明，ＴｉＯ３的掺入改变了ＮｉＣｒ相在金属陶瓷中的形貌，说明了ＮｉＣｒ与ＣａＳＺ的浸润性有一定的改善．ＸＲＤ和ＥＰＭＡ分析结果显示，ＴｉＯ２偏聚在ＮｉＣｒ金属相中，不影响ＣａＳＺ的稳定性．