330MW火电机组热系统节能诊断

利用火电厂热力系统节能诊断理论，对陕西蒲电二期N330-17．75／540／540型机组的热力系统运行方式、热力参数等进行了节能潜力分析和定量计算。利用等效热降理论进行定量诊断计算得出总节能潜力达到3．2g／kWh，可以显著地提高机组运行的经济性。     

虚拟仪器技术在雷达系统测试中的应用

分析了现代雷达系统对新一代雷达测试系统的要求,总结了虚拟仪器的发展、优势和关键技术,并对新一代雷达测试系统进行了展望.     

高炉铁口孔道侵蚀过程的模拟

从流体动力学的角度出发,建立高炉出铁口处流动的数学模型.基于对孔口出流出口处流线公式的推导并作适当修正,计算出铁时铁口孔道的侵蚀形状,并描述了侵蚀过程.通过水模型实验和模拟计算的方法分别模拟出侵蚀过程.实验与模型假设较为符合,可以为铁口区的维护以及推荐适宜的打泥量提供参考.     

Immune clonal coevolutionary algorithm for dynamic multiobjective optimization

In this paper, a new evolutionary algorithm, called immune clonal coevolutionary algorithm (ICCoA) for dynamic multiobjective optimization (DMO) is proposed. On the basis of the basic principles of artificial immune system, the proposed algorithm adopts the immune clonal selection to solve DMO problems. In addition, the theory of coevolution is incorporated in ICCoA in global operation to preserve the diversity of Pareto-fronts. Moreover, coevolutionary competitive and cooperative operation is designed to enhance the uniformity and the diversity of the solutions. In comparison with NSGA-II, immune clonal algorithm for DMO and direction-based method, the simulation results obtained on 5 difficult test problems and on related performance metrics suggest that ICCoA can achieve better distributed solutions and be very effective in maintaining the uniformity of Pareto-fronts.     

无线传感器网络LEACH路由协议研究与改进

针对LEACH算法随机选取簇头,未考虑节点剩余能量及单跳与sink节点通信造成能量损耗过快的问题。引入以剩余能量及邻居节点数作为权重因子的时间等候簇头竞争模式选取簇头,并提出LEACH与蚁群算法相结合建立簇间路由机制,采用局部信息素更新,综合簇头节点的剩余能量及节点距离,为簇首与sink节点通信建立多跳路由,达到降低簇头节点能耗过快的目的。仿真实验结果表明,改进算法在降低能耗、延长网络生命周期等方面较LEACH算法有较大提高。     

Polysiloxane-Based Polyurethanes with High Strength and Recyclability

Polysiloxanes have attracted considerable attention in biomedical engineering, owing to their inherent properties, including good flexibility and biocompatibility. However, their low mechanical strength limits their application scope. In this study, we synthesized a polysiloxane-based polyurethane by chemical copolymerization. A series of thermoplastic polysiloxane-polyurethanes (Si-TPUs) was synthesized using hydroxyl-terminated polydimethylsiloxane containing two carbamate groups at the tail of the polymer chains 4,4′-dicyclohexylmethane diisocyanate (HMDI) and 1,4-butanediol as raw materials. The effects of the hard-segment content and soft-segment number average molecular weight on the properties of the resulting TPUs were investigated. The prepared HMDI-based Si-TPUs exhibited good microphase separation, excellent mechanical properties, and acceptable repeatable processability. The tensile strength of SiTPU-2K-39 reached 21.5 MPa, which is significantly higher than that of other flexible polysiloxane materials. Moreover, the tensile strength and breaking elongation of SiTPU-2K-39 were maintained at 80.9% and 94.6%, respectively, after three cycles of regeneration. The Si-TPUs prepared in this work may potentially be used in gas separation, medical materials, antifouling coatings, and other applications.     

FvNST1b NAC Protein Induces Secondary Cell Wall Formation in Strawberry

Secondary cell wall thickening plays a crucial role in plant growth and development. Diploid woodland strawberry (Fragaria vesca) is an excellent model for studying fruit development, but its molecular control of secondary wall thickening is largely unknown. Previous studies have shown that Arabidopsis NAC secondary wall thickening promoting factor1 (AtNST1) and related proteins are master regulators of xylem fiber cell differentiation in multiple plant species. In this study, a NST1-like gene, FvNST1b, was isolated and characterized from strawberry. Sequence alignment and phylogenetic analysis showed that the FvNST1b protein contains a highly conserved NAC domain, and it belongs to the same family as AtNST1. Overexpression of FvNST1b in wild-type Arabidopsis caused extreme dwarfism, induced ectopic thickening of secondary walls in various tissues, and upregulated the expression of genes related to secondary cell wall synthesis. In addition, transient overexpression of FvNST1b in wild-type Fragaria vesca fruit produced cells resembling tracheary elements. These results suggest that FvNST1b positively regulates secondary cell wall formation as orthologous genes from other species.     

改进 8 邻域节点搜索策略 A ∗ 算法的路径规划

针对传统 A ? 算法所规划路径存在易触碰障碍物,冗余节点过多等问题。 提出了一种改进 8 邻域节点搜素策略 A ? 算法 的路径规划。 首先,在 A ? 算法中改进节点搜索条件,使得获得的节点与周围障碍物节点保持一定安全距离;然后利用垂距限 值法剔除改进后路径上的冗余节点,并保留关键节点;最后,基于关键节点利用 B 样条曲线拟合出一条平滑路径。 在不同规模 的多障碍物地图环境下进行多次实验与对比,结果表明,相比于传统 A ? 算法,提出的改进 A ? 算法,获得的路径节点与障碍物 节点的安全距离平均保持在 0. 46,路径节点平均减少了 66. 8%,有效提升机器人的工作效率和安全性。     

某四层砖混结构千斤顶顶升纠倾方案研究与应用

根据某四层砖混结构半幢楼下沉、倾斜、扭转以及墙体严重开裂等现象,应用工程概念(如结构变形协调原理等),采用单排千斤顶并用人工操作方式将半幢楼成功顶升纠倾,证明该技术能够应用于无圈梁无构造柱整体性较差的砖混结构。     

一维纳米氧化锌制备方法及生长机理浅析

氧化锌(ZnO)是一种优良半导体材料,一维纳米结构ZnO因其极大地应用前景,更是引起了研究者的高度关注与深入研究。归纳、分析一维纳米ZnO的气相、液相、固相三类制备方法及其生长机理,深刻剖析气相制备方法的三种生长机制及其研究概况,为实现一维纳米ZnO的可控制备提供研究基础,对一维纳米ZnO制备方法的研究具有一定的理论指导意义。