Template-assisted synthesis of lamellar mesostructured hydroxyapatites

Novel lamellar mesostructured hydroxyapatites have firstly been synthesized by template-assisted technique. The mild and nontoxic surfactant, phosphoric acid monododecyl ester (MAP), is used to act as a structure-directing template. The structure of sample was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscope and Transmission electron microscopy. The results indicate that the obtained sample is a well-organized lamellar mesostructured hydroxyapatite with a uniform layer spacing of 3.64 nm.     

Face recognition using elastic local reconstruction based on a single face image

In this paper, we propose a new face recognition algorithm based on a single frontal-view image for each face subject, which considers the effect of the face manifold structure. To compare two near-frontal face images, each face is considered a combination of a sequence of local image blocks. Each of the image blocks of one image can be reconstructed according to the corresponding local image block of the other face image. Then an elastic local reconstruction (ELR) method is proposed to measure the similarities between the image block pairs in order to measure the difference between the two face images. Our algorithm not only benefits from the face manifold structure, in terms of being robust to various image variations, but also is computationally simple because there is no need to build the face manifold. We evaluate the performance of our proposed face recognition algorithm with the use of different databases, which are produced under various conditions, e.g. lightings, expressions, perspectives, with/without glasses and occlusions. Consistent and promising experimental results were obtained, which show that our algorithm can greatly improve the recognition rates under all the different conditions.     

二阶A型Cooper变换的增强型

对二阶Ａ型Ｃｏｏｐｅｒ变换进行增强，放宽可用性条件，并证明了其正确性，最后举例说明其应用。     

论教育的公益性和营利行为

教育是一项公益性事业，追求公共利益是发展教育事业的基本目标，教育的公益性并不取决于办学形式，教育的公益性也不反对追求教育的功利价值和效率价值．教育的公共利益中也包含物质利益，其公益性是以市场经济为基础的。     

超市收费排队系统的性能比较及其进一步优化

详细统计了超市顾客的到达速率和顾客能接受的最大排队队长及最长等待时间,并了解了超市针对市场竞争采取的排队规定和措施,利用排队论的有关知识分析超市收银系统的特点,建立超市收银系统的数学模型,通过求解数学模型,得到模型的最优解决方案,最后针对超市收银系统的不足,对超市收银系统进行了改进。     

Ductile Phase Toughened Brittle Materials

Toughening of brittle materials by the inclusion of ductile phases is governed by several important factors which include ceramic-ductile phase interfacial bond strength, physical and chemical compatibility between ceramic and ductile phase, geometry and mechanical properties of ductile phase. The present understanding of the effect of these factors on toughening is reviewed and clarified. Continuous ductile phases (network, fibre or plate) are found to be more efficient for the toughening of brittle materials than discrete ductile particles. However, ductile particle toughened brittle materials have the advantages of material homogeneity isotropy and particularly better high temperature properties. It has been demonstrated that the influence of interfacial bond strength is determined by the geometry of the ductile phase in the composites. For the comparatively continuous ductile phase, such as ductile network, fibre or plate, comparatively weak inteffocial bond strength can promote partial debonding of the brittle matrix-ductile phase intedece during crack propagation and is beneficial for toughening. For discrete particulate ductile phase toughened brittle materials, the small gauge length of the ductile phase often results in the ductile phase pull-out during crack propagation which is the main limitation to toughening.Thus strong bond strength is required to ensure the bridging of the crack by the ductile phase.The coefficient of thermal expansion (CTE) mismatch between matrix and ductile phase has also been correlated with the geometry of the ductile phase. In most of the ceramic/metal systems,the CTE of the ductile metal phase is greater than that of the ceramic matrix. In the case of ductile network, fibre or plate, the residual stress created by the CTE mismatch can contribute to toughening through its influence on the initial crack opening stress while the bridging of the crack by the ductile phase is still ensured. However, for discrete ductile particles, the residual stress created by CTE mismatch is liable to cause cracks to by-pass the spherical particles, limiting the efficient use of the inherent toughness of the ductile phase. Low-modulus ductile inclusions are beneficial for the bridging of cracks by the ductile phase. Softer, more ductile inclusions are more effective for the toughening of brittle materials by particulate ductile phase     

SNCP环带链的组网与维护

在实际传输网络结构中,有些站点由于条件限制不能与其它站点连接成环.过去采用通道保护(PP)环带链组网,环链网元间业务在环上没有保护;随着技术的发展,提出了子网连接保护(SNCP)环带链组网方式,确保环链网元间业务在环上得到保护,使网络的稳定性和可靠性大大提高.     

Novel blood-compatible waterborne polyurethane using chitosan as an extender

A series of novel block polymers of polyurethane (PU) and chitosan have been prepared in two steps. The first step is the preparation of PU prepolymer, obtained from polytetramethylene oxide glycol (PTMO, M_n = 1000), isophrone diisocyanate (IPDI), and 2,2′-dimethylol propionic acid (DMPA), followed by ionizing PU prepolymer with triethylamine (TEA). The second step involves PU chain-extended by water-soluble chitosan of low molecular weight (M_n = 5000) by self-emulsion polymerization method. The sizes of the latex particles, morphology, and copolymer architecture have been characterized by dynamic light scattering (DLS), general tensile test, infrared spectroscopy (IR), surface contact angle measurement, and transmission electron microscopy (TEM). Furthermore, it shows that the addition of chitosan remarkably increases anticoagulative property of PU elastomers confirmed by the recalcification time. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Piezoelectric Nanogenerators for Self-Powered Nanodevices

A novel approach converts nanoscale mechanical energy into electric energy for self-powering nanodevices.In our own work, we've used piezoelectric zinc-oxide nanowire (ZnO NW) arrays to demonstrate a novel approach for converting nanoscale mechanical energy into electric energy. Here, we review the fundamental principle behind the nanogenerator, present an approach for improving its performance, and discuss some of the challenges we face in pushing this technology to reach its potential.