有线数字机顶盒前端技术发展与应用

有线电视数字化前景广阔，但是机顶盒前端组成则非常灵活，文中对前端的基本原理和几种组成方式进行了论述。介绍了一些主流芯片和解决方案的技术特点。并讨论了前端的发展方向和组成原则。     

立式屏蔽电泵气体密封型轴承结构介绍

为了解决石墨轴承屏蔽电泵无法输送介质中含有微小固体颗粒的难题，介绍一种由滚动轴承代替石墨轴承的气体密封型屏蔽电泵。     

链轮闸门设计问题的探讨

本文结合国内外工程实践，在链轮闸门的链轮及其走道、门叶结构及止水装置、门槽体型及埋件、启闭力与启闭机等方面，对选型、布置、材质、关键技术、计算方法、工艺要求、经验数据等问题作了较全面的探讨，供链轮闸门的设计和优化作参考。     

碾压混凝土中粉煤灰最大掺量的确定方法探讨

本文针对碾压混凝土中粉煤灰的最大掺量问题，通过试验和计算，得到长龄期时粉煤灰掺量与Ｃａ（ＯＨ）２含量的关系。由此提出两种确定粉煤灰最大掺量的方法：１．由粉煤灰颗粒与Ｃａ（ＯＨ）２的反应程度确定粉煤灰的最大掺量；２．由粉煤灰的可渗出物与Ｃａ（ＯＨ）２的反应确定粉煤灰的最大掺量。     

碾压混凝土坝与粉煤灰

本文内容包括两部分:第一部分介绍碾压混凝土的特性、类型和碾压混凝土坝的发展概况;第二部分专题阐述粉煤灰在碾压混凝土中的作用,并通过试验资料,理论分析了不同类型、不同掺量的粉煤灰对碾压混凝土工作度、强度、抗渗性、水化热等性能的影响。     

裹包执行机构——滚子直动盘形凸轮参数的优化设计

本文依据数学规化理论,并运用先进的计算技术,提出了一种适用于裹包执行机构——滚子直动盘形凸轮参数的设计方法,编制了简洁实用的优化设计程序。     

Effect of formulation composition on the properties of controlled release tablets prepared by roller compaction

This study discusses the effect of formulation composition on the physical characteristics and drug release behavior of controlled-release formulations made by roller compaction. The authors used mixture experimental design to study the effect of formulation components using diclofenac sodium as the model drug substance and varying relative amounts of microcrystalline cellulose (Avicel), hydroxypropyl methylcellulose (HPMC), and glyceryl behenate (Compritol). Dissolution studies revealed very little variability in drug release. The t₇₀ values for the 13 formulations were found to vary between 260 and 550 min. A reduced cubic model was found to best fit the t₇₀ data and gave an adjusted r-square of 0.9406. Each of the linear terms, the interaction terms between Compritol and Avicel and between all three of the tested factors were found to be significant. The longest release times were observed for formulations having higher concentrations of HPMC or Compritol. Tablets with higher concentrations of Avicel showed reduced ability to retard the release of the drug from the tablet matrix. Crushing strength showed systematic dependence on the formulation factors and could be modeled using a reduced quadratic model. The crushing strength values were highest at high concentrations of Avicel, while tablets with a high level of Compritol showed the lowest values. A predicted optimum formulation was derived by a numerical, multiresponse optimization technique. The validity of the model for predicting physical attributes of the product was also verified by experiment. The observed responses from the calculated optimum formulation were in very close agreement with values predicted by the model. The utility of a mixture experimental design for selecting formulation components of a roller compacted product was demonstrated. These simple statistical tools can allow a formulator to rationally select levels of various components in a formulation, improve the quality of products, and develop more robust processes.     

直线步进电机在压路机发动机转速控制系统中的应用

本文介绍了采用直线步进电机作为驱动装置的压路机发动机转速闭环控制系统。直线步进电机具有结构简单、免维护、可靠性高、能实现位移的精确控制等特点，将其应用于电控油门装置上是一种先进的技术方案。文中详细叙述了该控制系统的组成及原理和控制程序的结构及功能。应用实践表明，采用上述控制装置取得了良好的效果。     

强化汽车齿轮的有效途径：计算顶隙与齿轮弯曲强度

文章提出了计算顶隙的概述一面分析后指出计算隙可以极大地提高齿轮的承载能力，为产品设计人员设计高强度齿轮提供了一种行之有效设计方法。     

袋装生活垃圾破碎机辊筒的设计

城市生活垃圾袋装化已成为我国城市生活垃圾主要的收集方式。在垃圾预处理过程中需要破碎机。本文讨论了根据选择性破碎的原理，运用连杆机构，设计破袋破碎机的辊筒。当袋装生活垃圾由进料口进入破袋破碎机内，经过选择性破碎后，破碎刀片收缩至防缠罩内，同时防缠罩上的刷子将粘缠在破碎刀片上的垃圾去除，以清理缠绕物和实现自我保护功能。