“Segment-wise model” for theoretical simulation of barely visible indentation damage in composite sandwich beams: Part II – Experimental verification and discussion

When localized transverse loading is applied to a sandwich structure, the facesheet locally deflects and the core crushes. A residual dent induced by the core crushing significantly degrades the mechanical properties of the sandwich structure. In a previous paper, the authors established a “segment-wise model” for theoretical simulation of barely visible indentation damage in honeycomb sandwich beams with composite facesheets. Honeycomb sandwich beam was divided into many segments based on the periodic shape of the honeycomb and complicated through-thickness characteristics of the core were integrated into each segment. In this paper, the new model is validated by experiments using specimens with different types of honeycomb cores. In addition, the damage growth mechanism under indentation load was clarified from the viewpoint of the reaction force from the core to the facesheet. The applicability of the model to other types of core materials is also discussed.     

陶瓷废渣的再生利用技术及方向

阐述了当前陶瓷废渣所带来的环境危害以及利用现状，提出了以超细技术为基础，通过深加工，创新出陶瓷废渣利用的一条新的路子，同时提出了新的发展方向。     

Electrical conductivity of homopolymer and copolymers of <Emphasis Type="Italic">N</Emphasis>-vinylcarbazole

Poly(N-vinylcarbazole) (PVCz) is well known as an electroactive material due to its good photoconductivity, charge-transfer complexes, photoluminescence and electroluminescence properties. The block copolymers of N-vinylcarbazole were prepared and the effects of the relative composition, molar masses, architecture and doping on its electrical behavior were investigated. Controlled free radical polymerization has been carried out using nitroxide-mediated process in order to prepare a series of block copolymers of N-vinylcarbazole. 2,2,6,6-Tetramethyl-1-piperidinyloxy radical (TEMPO) was used to end-cap “living” homopolymer of p-bromostyrene, which was further used as a macroinitiator to polymerize N-vinylcarbazole and styrene. The copolymers have been doped at room temperature with LiClO₄ and the electrical conductivities were measured by two-probe method, which have shown to depend on copolymer’s relative composition and molar masses.     

FEP和多孔PTFE复合膜铁电驻极体的压电性及电荷动态特性

报道了将致密的FEP和多孔PTFE交互层叠在一起，采用热粘合的方法制备出具有孔洞结构的聚合物复合膜，然后经电晕极化处理使该复合膜成为铁电驻极体。最后用准静态方法测量该铁电复合膜的压电系数d33，并通过热刺激电流放电（TSD）电流谱和等温衰减研究了FEP和多孔PTFE复合膜铁电驻极体的电荷动态特性。结果表明：该复合膜的压电系数d33可达200～500pC/N，在0～12kPa的压强范围内呈现出良好的线性，并且在90℃下老化160min后仍保持在原来的43％且趋于稳定；FEP和多孔PTFE复合膜铁电驻极体电荷在热激发脱阱后复合途径主要有2种：一种是沿着固体介质的表面迁移与异性电荷复合，另一种是穿过固体介质层与异性电荷复合。在低温区（7512附近）前者占优，高温区（120℃附近）后者占优。     

微孔结构氟聚合物铁电驻极体的制备及其热稳定性研究

描述了一种微孔结构氟聚合物铁电驻极体的制备方法，利用准静态方法测量了该功能膜的压电系数如，并通过等温衰减和热刺激放电电流谱的测量研究了凼，的热稳定性。结果表明，这类氟聚合物铁电驻极体膜的准静态压电系数d33与热压时间有关；与聚丙烯（PP）压电驻极体膜相比较，氟聚合物压电驻极体膜不但具有更高的压电活性，而且呈现更优良的热稳定性。     

Electronic structure and transport properties of K-doped blue bronze Rb0.15K0.15MoO3

Single crystals of K-doped blue bronze Rb_0.15K_0.15MoO₃ and Rb_0.3MoO₃ have been investigated by measurements of the X-ray photoemission spectrum (XPS), electrical resistivity and thermoelectric power, respectively. Analysis of the XPS data reveals that two final states representing alternate screening channels coexist in Rb_0.15K_0.15MoO₃. Compared with the pure bronze, the Mo sites of the doped sample contain less 4d electrons which reflected in the movement of Mo3d spectrum. Due to the discrepancy of electronic structure, the K ion doping results in the notable increase of the single particle activation energy and decrease of the thermoelectric power in the charge density wave state.     

H<Subscript>∞</Subscript> Deconvolution Filters for Stochastic Systems with Interval Uncertainties

This paper is concerned with the robust H_∞ deconvolution filtering problem for continuous- and discrete-time stochastic systems with interval uncertainties. The matrices of the system describing the signal transmissions are assumed to be uncertain within given intervals, and the stochastic perturbation is in the form of multiplicative Gaussian white noise with constant variance. The purpose of the addressed problem is to design a robust H_∞ deconvolution filter such that the input signal distorted by the transmission channel could recover to a specified extent γ. By using stochastic analysis techniques and the Lyapunov stability theory, sufficient conditions are first derived for ensuring the asymptotical stability of the filtering error system. Then the filter parameters are characterized in terms of the solution to linear matrix inequalities, which can be easily solved by using available software packages. Two simulation examples are exploited to demonstrate the effectiveness of the proposed design procedures, respectively, for continuous- and discrete-time systems.     

框支短肢剪力墙结构中斜柱转换结构抗震试验研究

通过对两榀框支短肢剪力墙斜柱转换结构在竖向荷载及水平低周反复荷载共同作用下的拟静力试验,分析了试件的应力分布状态、破坏形态、荷载传递规律以及转换梁的受力性能和试件的抗震性能。试验结果表明,斜柱式转换结构受力特点类似于一个简单桁架,转换层上层传力梁强度和刚度对转换梁性能有重要的影响,设计合理的框支短肢剪力墙-斜柱转换结构具有较好的延性,可以形成多道抗震防线,从而获得较好的抗震性能。     

PJM输电权运行机制及其在我国区域电力市场阻塞管理中的应用

PJM电力市场采用节点边际电价(LMP)进行阻塞管理,利用点对点的金融性输电权(FTR)作为金融工具来分摊阻塞盈余、规避节点电价不稳定带来的市场风险。主要介绍了PJM电力市场中输电权的种类、输电权拍卖市场的特点、出清机制和结算方法。在此基础上,对我国区域电力市场的阻塞管理及输电权市场的设计提出了一些建议。     

基于遥感影像的长春城市用地建筑面积估算

基于知识规则的遥感影像分类方法以及空间网格技术(GRID)通过建立网格内城市建筑用地面积所含的阴影面积比例与容积率的关系,计算每个网格的建筑容积率,进而估算城市不同土地利用类型的建筑面积.结果表明:长春市2003年城市建筑总面积为135.98km2;用地类型平均容积率为商业用地＞公共建筑用地＞居住用地＞工业用地.基于知识规则的遥感分类方法以及空间网格技术(CRID)应用于建筑容积率估算不仅可以提高建筑容积率估算精度,而且进一步可以估算不同城市用地类型的建筑面积.