基于点云数据的鞋楦数控编程及其仿真

在刻楦机的数控编程中,文章针对测量所得的鞋楦点云数据,利用一种常见的方法来处理点云数据并进行了针对鞋楦离散模型的刀轨计算,并介绍了如何利用CGTech公司的Vericut软件来进行刀轨仿真.     

Clarity of blends of double-fractionated palm olein with low-erucic acid rapeseed oil

Double-fractionated palm olein (DfPOo) fractions with iodine values (IV) of 60 and 65 were each blended with low-erucic acid rapeseed (LEAR) oil in various proportions. Clarities of the blends at different temperatures were determined. Maximum levels of DfPOo-IV60 and DfPOo-IV65 in blends that remained clear at 20°C for at least 120 d were 40 and 80%, respectively. At 15°C, the maximum levels were 10 and 40%, and at 10°C, 10 and 20%, respectively. At 5°C, only a blend of 10% DfPOo-IV65 in LEAR remained clear for 120 d. Maximum levels of DfPOo-IV60 and DfPOo-IV65 in blends that passed the cold test were 30% for both palm oleins. Maximum levels of the palm oleins in blends with LEAR were higher than those of blends with soybean oil. Cloud points were lower in palm olein/LEAR blends than those of palm olein/soybean oil blends, probably because LEAR contains less saturated fatty acids than soybean oil.     

Physical properties of oleochemical carbonates

Carbonates are a class of compounds that have recently found increasing interest in commercial applications owing to their physical properties and relatively straightforward synthesis. In this work, physical and fuel properties of five straight-chain C_17–39 and three branched C_17–33 oleochemical carbonates were investigated. These properties included cetane number (CN), low-temperature properties, (kinematic) viscosity, lubricity, and surface tension. The carbonates studied had CN ranging from 47 to 107 depending on carbon chain length and branching. For the same number of carbons, the CN of carbonates were lower than those of FA alkyl esters owing to interruption of the CH₂ chain by the carbonate moiety. Kinematic viscosities at 40°C ranged from 4.9 to 22.6 mm²/s whereas m.p. ranged from +3 to below −50°C depending on the carbonate structure. High-frequency reciprocating rig testing showed the neat carbonates to have acceptable lubricity that improved as chain length increased. Finally, the carbonate's ability to influence cold-flow properties in biodiesel (methyl soyate) and lubricity in low-lubricity ultra-low sulfur diesel were examined. The carbonates studied did not significantly affect cold flow or lubricity properties at concentrations up to 10,000 ppm (1 wt%). The properties of the carbonates resemble those of fatty alkyl esters with similar trends resulting from compound structure.     

引汉济渭工程运行调度综合服务平台的应用实践

针对引汉济渭工程运行调度的实际需求和特点,基于云计算技术,采用面向服务的体系结构(SOA)和JAVA EE平台技术架构,研发了基于云服务架构的引汉济渭工程运行调度综合服务平台,建立了基于平台、组件、知识图及可视化工具灵活搭建的引汉济渭工程运行调度业务应用系统构建模式,形成基于平台、基于组件、基于主题、基于可视化的应用模式,解决了传统的工程运行调度系统应用性差、功能单一、可扩展性差及应用模式单一等问题。通过平台提供工程运行调度业务服务,为工程联合调度提供技术支撑。     

Miscibility of oligomeric poly(dimethyl siloxanes) with long-chain unbranched alkanes: 2. Unsymmetrical cloud point curves

Previously obtained cloud point curves for mixtures of oligomeric poly(dimethyl siloxanes) (weight fraction W₁) with oligomeric polyethylenes have been supplemented by the use of samples of higher molecular weight. Initial flat regions at low-medium W₁ as well as a slight shoulder at extremely high W₁ are now considered to be due to crystallization, since the temperatures at which they occur are the melting points of the oligoethylenes. The actual cloud point curves were of an unsymmetrical dome shape, the form of which could not be simulated by using a concentration-independent interaction parameter g in the Flory-Huggins equation. However, spinodals calculated by assuming a quadratic dependence of g on composition were of the same shape as the experimental cloud point curves. The critical compositions calculated on this basis were also close to the experimental ones.     

移动平台闸站监控系统的设计与实现

针对水利闸站监控系统对于应急信息和措施的需求, 提出了移动平台水利闸站监控系统。首先分析了系统的 整体框架结构, 然后实现了一套移动客户端软件完成水利闸站监控的功能。将手机客户端与云平台服务器相连, 通 过网络通信方式获取闸站现场传感器信息, 远程采集和存储数据, 客户端移动终端系统具有前端处理与计算能力通 过移动无线网络访问服务器, 实现了对多控制节点的远程监控。结果表明该系统能及时有效地获取闸站水利信息 并进行调度, 提高了水利信息化水平。     

一种融合服务满意度的多因素感知云服务性能预测策略

提出了一种多因素感知的云服务性能预测策略,它基于综合权衡服务提供商的利益,通过合理定价和性能保障来量化和优化服务满意度,并以之驱动性能预测,并引入效用理论实现服务满意度的合理定价.最后通过模拟实验表明,它能够降低SLA破坏率,有效提高云服务的资源利用率.     

一种基于同态标签的动态云存储数据完整性验证方法

在云存储服务中,为使用户可以随时验证存储在云存储服务器上数据的完整性,提出一种基于同态标签的动态数据完整性验证方法。通过引入同态标签和用户随机选择待检测数据块,可以无限次验证数据是否完好无损,并支持数据动态更新;可信第三方的引入解决了云用户与云存储服务供应商因数据完整性问题产生的纠纷,实现数据完整性的公开验证;然后给出该方法的正确性和安全性分析,以及该方法的性能分析;最后通过实验验证了该方法是高效可行的。     

二维多层次的云服务可靠性评估方法研究

针对云服务业务流程管理的特点, 给出了云服务的组合实现框架; 依据随机Petri网的建模理论, 探讨了组合云服务流程网模型的细粒度建模方法; 根据动态多变的用户需求, 设计了二维多层次的云服务组合可靠性动态评估框架, 并给出了马尔可夫过程和等值约简的两种可靠性计算方法。应用示例分析结果表明, 该方法具有较好的动态适应性和灵活性, 能有效满足云服务的可靠性评估需求。     

一种用于云存储的可撤销的属性加密方案

由于云存储用户数量大,成分复杂,云存储中数据的安全防护问题成为其发展的一大制约,近年来,基于属性加密技术解决云存储中数据安全存储问题成为研究热点,但传统的属性加密方案存在密文长度相对较大且属性撤销复杂等问题。引入代理重加密技术,针对以上问题提出一种可撤销的密文属性基加密方案,在缩短密文长度的同时实现属性撤销操作,并证明该方案在DBDH假设下CPA是安全的。