国外以合成生物高聚物为基的可降解塑料

目前国外有三类重要的生物降解塑料,第一类是以天然高聚物为基的,第二类是以天然单体合成的高聚物为基的,第三类是以发酵过程生产的高聚物为基的。第一类已有大量论文报道,本文只综述第二类及第三类生物降解塑料的制造、特点、应用及发展现状和前景。     

Volume phase transition of polyelectrolyte gels in dimethyl sulfoxide/ tetrahydrofuran mixtures

Copolymer gels were prepared from 2-(acrylamido)-2-methylpropanesulfonic acid (AMPS), N,N-dimethylacrylamide (DMAA, comonomer) and N,N′-methylenebis(acrylamide) (BIS). The mole fraction of AMPS were 0.2674 and 0.4318, respectively, with the same BIS mole fraction of 0.013. These gels with counterions H⁺, Na⁺, and K⁺ were swollen at 25°C in mixtures of dimethyl sulfoxide (DMSO) and tetrahydrofuran (THF). A volume phase transition was observed at the THF volume fraction of about 0.58, indicating that the volume phase transition in a polyelectrolyte gel occurs when the medium polarity decreases sufficiently for ion-pair formation. On changing the counterion, the fraction of DMSO in the solvent mixture which is required to initiate swelling decreases in the order Na⁺, H⁺, and K⁺, the same as for counterion condensation in identical gels.     

Precise localization of eye centers with multiple cues

Automatic detection and precise localization of human eye centers are the essential processes in photo related multimedia applications. Since eye center points are used as reference base points for further intelligent processing, precise eye center localization is very important. In face recognition the accuracy of localization of eye centers directly influences the identification accuracy. A multiple stage approach with multiple cues for detection and precise localization of eye centers is presented in this paper. Multiple scopes searching strategy is used for correctly extracting eye patch images from the background. Dedicated gradient based features and curvelet based features are constructed and used for comprehensively revealing the intensity distribution characteristics and the edge based texture around eye centers. A rebuilt score calculation mechanism is proposed and the rebuilt scores are used as a specific measurement index reflecting the matching accuracy. The final localizations of eye centers are determined with integrating the gradient based scores and curvelet based scores. The experiment results testing on public face datasets show that the localization accuracy of proposed approach outperforms the accuracy with other state of the art methods.     

基于SOA的智能航运数据服务平台研究

为了实现全国范围的内河航运数据共享,提高我国内河航运的管理水平,需要一种稳定可靠、松耦合的数据共享方式。针对当前的内河航运数据共享需求,并根据当前我国各省的内河航运信息化建设的实际情况,参考国内外成熟的理论基础,提出了基于SOA的数据共享体系,从而实现多节点的关键数据实时共享的应用场景。通过这种方式可以实现内河航运数据共享服务,满足航运信息服务的要求,并适应今后不断增长的共享节点及共享压力。     

ZnO-B2O3-P2O5系封接玻璃的研究

采用熔融法制备了ZnO-B2O3-PO5 系无铅磷酸盐封接玻璃，研究了组成对玻璃结构、特征温度、热膨胀和化学稳定性的影响。结果表明：B2O3和P2O5为玻璃网络形成体，ZnO含量较低时可以参与到玻璃网络结构中，提高玻璃的稳定性；玻璃转变点Tg、熔制温度Tm、封接温度Ts、软化点Td都随P2O5／B2O3减小而增加；B2O3／ZnO是影响玻璃熔制温度的主要因素；ZnO含量对玻璃密度和热膨胀系数影响较大。ZnO-B2O3-PO5 系玻璃在中性环境下的化学稳定性较好。。     

碳纤维水泥石电阻测试方法研究

准确测量碳纤维水泥石的电阻率是碳纤维水泥石的压敏和温敏性能得以应用的关键问题之一。已有研究表明，电阻率测量结果准确性受电极的制作形式及电阻的测试方法影响较大。本文在试验的基础上，分析了几种适用于碳纤维水泥石的电极布置形式的特点及两极法和四极法对电阻测试结果的影响。研究表明，碳纤维水泥石电阻宜采用插入式四极法测量。     

Thermal and crystallization characteristics of poly(ethylene terephthalate) with poly(oxybenzoate‐p‐trimethylene terephthalate) copolymer

Poly(ethylene terephthalate) (PET) was blended with two different poly(oxybenzoate‐p‐trimethylene terephthalate) copolymers, designated T28 and T64, with the level of copolymer varying from 1 to 15 wt %. All samples were prepared by solution blending in a 60/40 (by weight) phenol/tetrachloroethane solvent at 50°C. The crystallization behavior of the samples was studied by DSC. The results indicate that both T28 and T64 accelerated the crystallization rate of PET in a manner similar to that of a nucleating agent. The acceleration of PET crystallization rate was most pronounced in the PET/T64 blends with a maximum level at 5 wt % of T64. The melting temperatures for the blends are comparable to that of pure PET. The observed changes in crystallization behavior are explained by the effect of the physical state of the copolyester during PET crystallization as well as the amount of copolymer in the blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1599–1606, 2002     

基于中国电信CEP协议的组件服务应用

面对复杂多变的需求,需要我们梳理出业务的本质,并设计一套与之相适应、易扩展的框架结构,让业务组件化,组件服务化,通过灵活的服务组装,来满足灵活多样的业务需求。本文旨在通过对中国电信CEP协议的剖析,指引如何通过对整个CEP层次结构进行归纳总结,体系化实现服务能力的封装与开放。     

浅谈现代油库中的信息化建设

随着我国科学技术水平和社会经济实力的不断提高,现如今的油库管理应该做到现代化、信息化.在油库管理的信息化建设中,计算机及其系统起到了至关重要的作用.本文介绍了油库管理信息系统的设计原则与具体内容,并详述了计算机系统是如何在油库的信息化管理中应用的.     

Finite‐time formation control of multiple nonholonomic mobile robots

This paper considers finite‐time formation control problem for a group of nonholonomic mobile robots. The desired formation trajectory is represented by a virtual dynamic leader whose states are available to only a subset of the followers and the followers have only local interaction. First of all, a continuous distributed finite‐time observer is proposed for each follower to estimate the leader's states in a finite time. Then, a continuous distributed cooperative finite‐time tracking control law is designed for each mobile robot. Rigorous proof shows that the group of mobile robots converge to the desired geometric formation pattern in finite time. At the same time, all the robots can track the desired formation trajectory in finite time. Simulation example illustrates the effectiveness of our method. Copyright © 2012 John Wiley & Sons, Ltd.