传感器网络启动式自组织方法

无线传感器网络如何形成一个有序的自组织网络结构是一项重要研究内容,针对按地理区域交替性工作的动态监测网络,提出了相应的网络自组织方法,该方法以启动式方式运行网络,通过单播信令的方式分配MAC地址,标记相邻节点。在数据转发过程中以局部最小代价函数为准则转发数据。仿真实验表明,该自组织方法具有较短的MAC地址,适宜相应的网络环境。     

Measurement of density of the gap states ina-Si:H by the normalization of photoconductivity

The spectra of the optical absorption coefficient in low absorption region are obtained by using a normalization procedure for the photoconductivity spectra. The results are explained in terms of the optical transition of electrons from localized states in the exponential valence band tail and in dangling bond states 1.0 eV below the conduction band edge to extended conduction band states. Then the density of the gap states below the Fermi levelE _F is obtained. From the investigation of recombination kinetics, the average density of the gap states over the range of ) and the density of the gap states above the Fermi levelE _F are obtained. These indicate that the width of the conduction band tail is smaller than that of the valence band tail.     

改善30Cr2MoV钢大锻件冲击韧性及晶粒度的研究

通过模拟试验及生产试验,对改善30Cr2MoV钢锻件冲击性能及晶粒度进行了分析研究,找到了较为有效的热处理方法,可使用的FATT达到20℃以下,晶粒度达到6级以上。     

Cu—Cr合金电极触头板铸件的熔制

含０．４％～１．０％Ｃｒ的Ｃｕ－Ｃｒ合金具有优良的导电、导热性能，铸件经热处理强化后可获得较高的综合力学性能。近年来该合金作为一种新材料被广泛地用于制作电子工业、电器设备上的电极触头板、接触环、夹持体等零件。Ｃｕ－Ｃｒ合金存在易氧化吸气、凝固范围窄、收缩较大、易形成集中缩孔等缺陷，这些铸造特性给生产优良的Ｃｕ－Ｃｒ合金铸件带来一定的困难。以采用常规的熔炼设备和造型材料熔铸出Ｃｕ－Ｃｒ合金铸件——高压大电流电极触头板为例讨论这一熔铸的工艺方法。     

添加WC对镍基合金激光熔敷层硬度及腐蚀磨损行为的影响

探讨了添加ＷＣ的镍基合金Ｇ１１２激光熔敷层的性能，结果表明，添加２０％ＷＣ的激光熔敷层的硬度ＨＶ０．２比末添加的提高近一倍，在酸性介质中的耐蚀性有所降低，但腐蚀磨损性能却得到大改善，其腐蚀磨损机制在低冲击速度下，由犁削磨损，坑穴腐蚀及应力腐蚀变为犁削磨损为主，在高冲击速度下，两者的腐蚀磨损机制趋于一致，均为犁削磨损为主，伴以抗穴腐蚀及应力腐蚀。     

CO2气体保护的激光焊接12mm厚低碳钢板

采用CO2 作为保护气体消除大熔深激光焊接低碳钢时易发生的气孔问题 ,并对比研究了CO2 和Ar气保护条件下 12mm厚低碳钢板激光焊缝的组织和韧性。焊接试验利用 4kWNd :YAG激光器 ,采用双面深熔焊的方法 ,焊接条件为 4kW激光功率和0 .3 ,0 .5m/min的焊接速度。冲击试验采用一种自行设计的带侧面缺口的三缺口冲击试样 ,以保证断裂全部发生在焊缝。结果表明 ,利用CO2 作保护气体焊接低碳钢板 ,可以有效消除大熔深激光焊接时的气孔问题 ,并获得比Ar气保护下硬度较低 ,冲击韧性高的焊缝。研究工作为解决大功率激光深熔焊时容易发生的气孔问题提供了一条有效途径     

形成针对太湖流域三类水源的综合解决方案实现典型和新型污染物的协同控制

太湖流域是我国典型的水质缺水型地区,饮用水安全保障工作面临较大挑战。"十三五"水专项"太湖流域饮用水安全保障工程技术与综合管理技术集成研究"课题梳理了太湖流域饮用水专项实施以来的课题及关键技术,针对太湖流域水源水质特征和区域供水特征,通过水源水质评估、关键技术遴选、工艺协同优化和示范工程验证,形成了针对太湖流域三类典型水源水质特征的分类综合解决方案,实现了典型和新型污染物的协同控制,以期为太湖流域饮用水安全保障提供技术支撑,为国家饮用水安全保障战略实施提供可借鉴的方案。     

Synergistic effects of organically modified montmorillonite in combination with metal oxides on the fire safety enhancement of intumescent flame-retarded epoxy resins

Synergistic effects of organically modified montmorillonite (OMMT) in combination with different metal oxides (Bi₂O₃, Sb₂O₃, and MoO₃) on the fire safety enhancement of the intumescent flame-retarded epoxy resins (EPs) were systematically evaluated. The results from X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses show that the OMMT and metal oxides acquire a uniform distribution in the EP matrix, and OMMT platelets exhibit a fully exfoliated state. The flammability and thermogravimetry (TG) tests show that the intumescent flame retardant (IFR)-OMMT-metal oxide ternary system can endow EPs with the higher synergistic efficiencies on the enhancement of flame retardancy, smoke suppression properties, and charring ability compared to those of IFR or IFR-OMMT system, and the synergistic efficiency is the following order: IFR/OMMT/Sb₂O₃ > IFR/OMMT/MoO₃ > IFR/OMMT/Bi₂O₃. In particular, the sample, filled with 1.5 wt% OMMT, 1.5 wt% Sb₂O₃, and 27 wt% IFR, passes the UL94 V-0 rating and acquires the highest limiting oxygen index value of 28.5% among the samples. The IFR-OMMT-metal oxide ternary system exerts a better synergistic effect on the generation of crosslinking and aromatic structures that supply the excellent charring effect and barrier effect for the EPs, and the synergistic efficiency of IFR-OMMT-metal oxide ternary system is varied with the types of metal oxides.     

Pd/Mg(OH)2 Heterogeneous Nanocatalysts Synthesized by a Facile One-Pot Hydrothermal Method for CO Direct Esterification to Dimethyl Oxalate

Catalysis Letters - Pd-based heterogeneous nanocatalysts have wide application in chemical industry. However, the traditional synthesis process contains multi-steps such as impregnation, dry,...     

Novel Mo-V Oxide Catalysts with Nanospheres as Templates for the Selective Oxidation of Acrolein to Acrylic Acid

Catalysis Letters - Novel Mo-V-PMMA and Mo-V-PS catalysts are prepared by addition of hard polymethyl methacrylate (PMMA) and polystyrene (PS) nanospheres into Mo/V compounds in the preparation...