Prediction of the elastic behaviour of hybrid and non-hybrid woven composites

A micromechanical model called MESOTEX is presented for prediction of the elastic behaviour of composites reinforced with non-hybrid weave (plain weave, satin weave and twill weave) and hybrid weave (hybrid plain weave and hybrid twill weave) fabrics. By using the classical thin laminate theory applied to each woven structure, this analytical model takes into account the strand undulations in the two directions and also integrates the geometrical and mechanical parameters of each constituent (resin, fill and warp strands). A representative volume is chosen for each woven composite and the fibre architecture is described by several functions. To determine the effectiveness of this analysis, the elastic properties predicted for each woven composite are compared with experimental results and results extracted from the literature. This correlation shows excellent agreement between measured and predicted values, with a very low calculation cost (CPU time of less than 0·01 s).     

The Stability of Rare Earth-Iron-Nitrides Sm_2(Fe,M)_(17)N_y,Permanent Magnets

The effects of the partial substitution of element M(M=Cr,V,Mn,x=0.05;Zr,Ga,x=0.017;Si,x=0.15;Co,x=0.10)for Fe in samarium-iron-nitride Sm_2(Fe_(1-x)M_x)_(17)N_y compounds on their stabilitiesand Curie temperatures have been studied.It is found that Co,Ga can raise the Curie temperature of thecompounds.The initial decomposition temperatures cannot be raised significantly by all the studied elementsexcept Co.The result contradicts the formation enthalpy consideration.The final decomposition tempera-tures can be raised by all of the substitution elements.The effects of atmospheres on their decomposition be-havior were also studied.The results show that oxidation is the major reason for magnetic deterioration ofthe powder heated in air.Compared with nitrogen atmosphere,argon or vacuum helps to delay the decompo-sition of the compounds.     

Insulin-like growth factor binding protein-1 at mouse neuromuscular synapses

The insulin-like growth factor (IGF) signaling system includes the growth factors and their cell surface receptors, along with circulating IGF binding proteins (IGFBPs) that may alter and modulate the action of these neurotrophic hormones. These IGFBPs, along with IGFs and receptors, have been detected in various tissues including the brain. In this study, using polyclonal antibody to human IGFBP-1 or bovine IGFBP-2, we found that mouse muscle extracts contain similar-sized proteins that cross-react with these antibodies on Western immunoblots. After establishing that these antibodies reacted with the homologous murine IGFBPs, we performed immunocytochemistry to demonstrate the localization of IGFBP-1 at the neuromuscular junction, a model nicotinic, cholinergic synapse, as well as within intramuscular nerves. IGFBP-2, a distinct macromolecule, is present on the surface of muscle fibers and is not present within synapses or nerves.     

Automatically modeling, simulating and explaining physical systems

This paper presents an interactive framework for constructing models from high-level specifications of real physical systems, deriving low-level simulations from the constructed models and then generating explanations of the simulated behavior to help engineers interpret and control the real physical systems. To demonstrate our method, we show an example of modeling river networks, which are eco-environmental engineering systems, to provide a computer-based solution to problems of simulating and controlling concentrations of water quality constituents in river networks[1].     

Carbon fibre composites based on polyimide/silica ceramers: aspects of structure-properties relationship

Polyimide/silica ceramers, based on the products of the hydrolysis of tetraethoxysilane (TEOS) and a commercial poly(amic acid) solution, were used to fabricate unidirectional carbon fibre composites, which were subsequently evaluated with respect to thermal and mechanical properties. There is evidence to suggest that the silica component of these ceramers is present as dispersed discrete particles at low silica concentration (i.e. 7 wt%) and as fine interconnected domains trapped within the polyimide matrix at higher silica content (i.e. 14 wt%). The dimensions of the silica domains were in the region of 7–20 nm. Carbon fibre composites produced from ceramer solutions (CF/ceramers) were found to exhibit lower thermal expansion and a greater retention of flexural and interlaminar shear properties at elevated temperature than the corresponding polyimide-matrix composites (CF/polyimide). The properties of CF/ceramers were generally better for systems containing the higher amount of silica and were improved further by lowering the pH value of the precursor ceramer solution. This is believed to have resulted from the enhanced fluidity of the ceramer gel within the pre-impregnated fibres, giving rise to a higher packing density of the fibres and a more homogeneous distribution of fibres. CF/ceramers were also found to exhibit a better thermal oxidative stability at 350°C than the corresponding CF/polyimide, although a substantial amount of porosity developed in the case of ceramers with the higher silica content.     

增值税发票抵扣联移动认证系统的研究

无线通信技术和无线通信终端设备的发展为增值税发票抵扣联移动认证系统的研发提供了技术支持。文章从企业的实际需求为设计出发点,选择Visual Studio2005之C#作为本系统开发环境,综合利用微软移动通信技术(Microsoft Windows Mobile)和汉字设别技术,研发了增值税发票抵扣联移动认证系统。该系统通过"取得增值税专用发票→文字识别→无线认证→认证结果接收"等流程实现了增值税发票抵扣联的移动认证。     

“健康云”如何实现医疗信息化综述

对云计算技术实现医疗信息化的背景、研究基础、核心技术进行探讨,具体阐述了“健康云”在居民电子健康档案中的应用以及在医院信息管理系统中的应用,包括系统特点、整体架构等方面,并对其未来发展予以展望。     

A formal model for the interoperability of service clouds

Large-scale service-oriented computing is based on the idea that services from various servers are combined into one distributed application. Referring to a collection of services on one server as a ??service cloud??, the problem investigated in this paper is to define formal high-level specifications of such distributed applications and to enable the location of suitable services for them. Based on the language-independent model of Abstract State Services (AS²s), which serves as a universal integrated model for data and software as services, we extend AS²s by high-level action schemes called ??plots?? as a means to specify permitted sequences of service operations. On these grounds, we develop a model for service mediators, that is, specifications of composed services in which service slots have to be filled by actual services, and investigate matching conditions for slots of mediators and services. For a services to match a slot in a mediator, a (generalised) projection of the mediator must comply with the plot of the service. Furthermore, the service must be semantically adequate, which requires the use of a service ontology.     

多分量调频信号的阵列处理时频交叉项的抑制方法

在应用时频-MUSIC方法对多分量调频信号进行到达角估计的问题中,针对时频分布中交叉项的存在对估计性能的影响,提出了一种基于阵列信号处理抑制时频分布交叉项的新方法。该方法利用多信源在各阵元上的延迟对时频分布交叉项振荡相位的影响,联合运用多通道信号处理和图像处理的方法,采用二维乘法滤波,减小高频振荡交叉项在时频图像中的占据区域,从而达到抑制交叉项的目的。仿真实验显示该方法具有良好的效果。     

Assessing Optimal Digital Elevation Model Selection for Active River Area Delineation Across Broad Regions

Water Resources Management - The Active River Area (ARA) is a spatial approach for identifying the extent of functional riparian area. Given known limitations in terms of input elevation data...