海能达无线通信解决方案在民用建筑中的应用

针对民用建筑通信需求、规模．结合无线通信产品与技术的发展趋势,介绍海能达为物业小区、大型商场、博物馆、展览馆等民用建筑提供的弱场覆盖解决方案,以及海能达数字无线互联系统在局域网和广域网中的应用。     

膨胀土渠道边坡的破坏与防治对策

膨胀土边坡的破坏在工程中极为常见,它是岩土工程的一个难题。当前对其破坏形式和破坏机理仍未形成统一的认识,影响了问题的解决。在对膨胀土地层结构分析的基础上,通过两个大型的现场试验,并结合许多滑坡实例,概括出膨胀土坡两种典型的滑动形式,即浅表层的膨胀型滑动(塌坡)和中深部的裂隙性滑坡,对膨胀土边坡的破坏有了新的认识。并分析了滑动的机理和影响因素,并对相应的处治对策提出了建议。     

Kinetic Description of Industrial Wastewater Ozonation Processes

Literary and experimental data on the ozonation kinetics of aqueous solutions and wastewater were analyzed. COD was suggested to be used as a kinetic parameter from the solution side. On the basis of the results obtained from the ozonation of model solutions and wastewater, the rate coefficient by COD of the reaction was shown to be constant during separate stages of the process. Due to the consumption of fast-reacting components and entering into the reaction of more slowly reacting intermediate products, the rate coefficient changed spasmodically with transition from one stage to another. The reaction order with respect to the COD of the solution was shown to be equal to the reaction order with respect to the pure component.     

Correlation between chain conformations and optical anisotropy of thin films of an organo-soluble polyimide

An organo-soluble polyimide was successfully synthesized by two step polycondensation accompanied with chemical imidization. Optical anisotropy of thin films was detected by a prism-coupler technique. The results showed that the optical anisotropic properties of thin films prepared from solutions in different solvents depend on the solution properties. It is concluded that the more expanded the chain conformation in solution, the larger the negative birefringence of thin films. © 1997 Elsevier Science Ltd.     

Effect of body-borne equipment on injury of military pilots and aircrew during a simulated helicopter crash

Military helicopter pilots are expected to wear a variety of items of body-borne equipment during flight so as to be prepared for any situation that may arise in combat. Helicopter seats are designed to a specified weight range for an occupant with equipment. This paper investigates how distributing the equipment on the body affects injury potential during a helicopter crash. A finite element model representing a helicopter seat with a fully deformable 50th percentile Hybrid III carrying equipment was developed. The model was subjected to a standard military certification crash test. Various equipment configurations were investigated and analysed to determine its influence on the risk of injury. It was found that placing the equipment low on the torso, i.e. near the thighs, not only reduces the likelihood of injury in the lumbar, spinal region but also provides favourable results in neck and head injury risk when compared to other configurations investigated. In contrast, placing equipment high on the torso, i.e. close to the chin, increases the lumbar load and implicitly, the risk of head injury. A statistical analysis is carried out using the Wilcoxon Signed Rank Test to deliver probability of loads experienced within a certain interval. This study recommends an equipment configuration that improves survivability for an occupant seated on a fixed load energy absorbing seat which is subjected to Military Standard 58095A Test 4.     

浅析印刷过程中纸张起皱的原因及解决办法

印刷过程中纸张起皱是常见故障之一,其影响因素主要有纸张(含水量、质量、纸张类型等)、印刷机具(机械精度、调节精度、操作人员的技术水平等)、印版处理等等。防止起皱一要保证纸张干湿度均匀、适中,二是要保证印刷机具的精度,三是要合理处理印版。     

浅谈连续数据保护解决方案在医院中应用

由于在医院中会有很多对于病案、物资、药剂等需要进行统计的东西,尽管也应用了HIS、LIS、RIS等的多个信息管理的系统,建立生产中心机房和灾备中心机房。虽然这些举措切实增强了工作效率和便于医生进行决策,提高了医院整体的管理效率。那么为了更好的全面防御故障与灾难,以及确保医院的业务运行不中断,医院决定采用美国飞康公司所生产的CDP连续数据保护方案,这个方案能够提供一系列的措施来全面保护医院一关键业务系统：     

SQL注入检测与防范方法研究

随着互联网的发展,Web应用程序开发也变得越来越普及.但目前很多B/S模式的Web服务技术的应用程序,在设计之初,都未能充分考虑数据的校验与过滤.因此,这些应用在使用中就存在着不少的安全隐患,SQL注入的攻击方式便乘虚而入.本文分析了SQL注入攻击的原理、特点,并对常用的注入方法进行了总结.最后,在主动防御的基础上,针对软件测评工作,提出了一套防范SQL注入的安全方案和思路.     

Encapsulation of perfluorocarbon gases into lipid-based carrier by PGSS

For the first time, gas-filled microparticles were successfully prepared using a supercritical fluid based technology. Low molecular weight perfluorcarbon (PFC) gases, C₃F₈ or C₄F₈, have been encapsulated into Gelucire^® 50/13 (lipid-based carrier: polyethylene glycol glycerides), using PGSS^® (Particles from Gas Saturated Solution) technique. Particles were produced from the fast expansion of the melted lipid carrier saturated with a mixture of (CO₂ + PFC). The presence of the gas into the produced microparticles was verified by Nuclear Magnetic Resonance (NMR) analysis of fluorine atom. The effect of carrier to PFC mass ratio and PFC structure on the entrapment efficiency of the PFC gas into the particles was evaluated at fixed at 8.5 MPa and 353 K. These parameters were fixed in a preliminary study according to the morphology, size and flowability of the particles. The stability of encapsulated C₄F₈ in microparticles showed to be higher than C₃F₈; it was determined to be 2 h, at room conditions at the optimized carrier: PFC mass ratio of 30:1.     

The development of a response surface model for the determination of infinite dilution partial molar volumes and excess volumes from dilute multi-component data alone. Implications for the characterization of non-isolatable solutes in complex homogeneous reactive systems

A non-ideal system containing several solutes, e.g. methanol, acetone, and 2-butanol in n-hexane was studied. Traditionally defined excess molar volumes (based on pure component molar volumes) of the multi-component solutions were measured in the limit of infinite dilution in n-hexane using a vibrating-tube densitometer at and . An experimental design in the concentration range 0.0015<x_solute-i<0.023 was explored, optimizing the metric distance among the solutes to avoid clustering. The partial molar volumes of methanol, acetone, and 2-butanol at infinite dilution determined from the multi-component data were very consistent with the values obtained from separate binary experiments. Next a total molar volume response surface model was developed. Only experimental total volume and component moles are needed for analysis. The partial molar volumes of all the solutes were accurately predicted from the multi-component data alone. A new expression for excess molar volume is proposed to express component interactions. This approach is undoubtedly of considerable usefulness for determination of the partial molar properties of non-isolated but observable species in multi-component reactive solutions.