植被散射实验数据的特性分析

本文根据电波所获取的各种樾 射实测数据，分析了它们对不同极化波的响应特性。     

面向对象工程数据库管理系统O2S并发事务模型

Ｏ２Ｓ是我们在ＳＵＮ工作站上开发的一面向对象工程数据库管理。本文针对工程应用域事务的嵌套性，长时性，数据库逻辑分区性和涉及数据量大的四个显著特点，阐述了Ｓ２Ｓ的事务管理模型。对工程域事务的管理，数据库的恢复和封锁技术进行了讨论。     

C++程序设计教学中的技能培养

本文阐述了知识与技能的关系,以及C++程序设计教学中知识和技能的双重性要求。以选择语句为例,演示了"先知识后技能"的教学过程。实践证明,这样的教学安排行之有效。     

VPX总线标准研究及其在无人机中的应用展望

军用无人机以其低成本高效能、体积小隐身性能强、零伤亡等优势,被广泛应用于作战的各个阶段;但随着军事职能的拓展,传统无人机已无法满足在超恶劣战场环境下,完成多任务、分布式数据处理和大容量数据传输的要求,迫切需要一种新的、基于高性能传输总线的、支持多任务处理的无人机设备;VPX标准作为VME标准的升级版本,在国外无人机领域已有所应用;作为新一代军用加固总线产品,它满足串行、千兆高速数据率,支持PowerPC架构且扩展灵活,以其搭建无人机系统,完全可以满足现在乃至未来的需求;通过对无人机未来发展趋势及相关技术驱动因素分析,详细介绍了VPX及其后续OPENVPX标准,将其与之前版本总线进行比较,认为其在无人机系统各领域具有广泛的应用前景,最后给出一种基于VPX总线的无人机系统模型。     

The α- to β-Si3N4 transformation in the presence of liquid silicon

The compacts consisted of , -Si₃N₄ and free silicon are heat treated in the range 1650° C to 1750° C in an argon atmosphere in order to observe the following behaviours; the to phase transformation and variations of the microstructure during heat treatment in silicon nitride. For the microstructural observation of the heat treated specimens, the same grains in the polished surface were investigated before and after eliminating the retained silicon by etching. The to phase transformation, in this case, occurs via silicon melts irrespective of added -Si₃N₄. Both and phases are soluted and precipitated into molten silicon and their morphology are changed from an equiaxed shape to prismatic one. Although elongated grains are precipitated at low temperature or in the early stage of heat treatment, fine precipitated grains are mainly observed with increasing heat treating temperature.     

基于HCPN的发电企业项目管理工作流建模

如何对工程项目的成本、进度、质量情况进行控制和跟踪是发电企业的重要问题,应用工作流可通过对业务流程的整合及资源的合理分配解决这一问题。本文基于分层着色Petri网(HCPN),将工作流过程模型的逻辑结构和语义与HCPN中的网结构进行映射,进而利用CPN-TOOLS定义基于HCPN的项目管理工作流过程模型,并利用化简原则对工作流模型进行畅通性验证。     

Thermal cross-linking and anti-meltdrop properties of copolyester containing phosphorus/magnesium salt composites by in situ polymerization

Polyester is widely used in household products because of its good mechanical properties and wears resistance, but polyester is easy to ignite and inclined to produce droplet, so its application range is limited. The cross-linkable magnesium hydroxide nanoparticles were incorporated into flame-retardant polyester, which enables the phosphorus-containing copolyester with thermal cross-linking and anti-meltdrop properties. The nanoparticles were achieved by in situ polymerization and acted as a nucleating agent for improving the crystalline properties of the copolyester. Furthermore, the nanoparticles also enhanced anti-meltdrop properties and reduced the heat and gas release during the combustion process of the copolyester. The maximum heat release rate and total smoke release reduced by 39.8% and 74.4% compared with pure polyester. Specifically, the combustion products of the nanoparticles and phosphorus flame retardant could act a barrier role by covering the carbon layer to isolate air and heat, thereby resulting in excellent anti-meltdrop properties. The simple modification method reported here realizes the collaborative modification of flame retardant and anti-meltdrop properties of phosphorous flame-retardant copolyesters by thermal cross-linking.