Achieving C/CuO microfiber composites with efficient microwave absorbing performance at low thickness

Journal of Materials Science: Materials in Electronics - The carbon fibers with low density still face significant microwave absorbing application issues due to their high dielectric constant....     

A density functional theory study on the interaction between UO_2~(2+) and the carbamoylphosphoramidic acid ligand for uranium extraction from seawater

Phosphorylurea molecules, which contain both phosphoryl and carbonyl groups, are considered efficient extractants for UO_2~(2+). This study aims to explain the complexation of UO_2~(2+)with carbamoylphosphoramidic acid(CPO), a simple model for phosphorylurea, for ligand design for uranium recovery from seawater using density functional theory calculations, natural bond order analysis,and the quantum theory of atoms in molecules. The results showed that, when CPO acts as a monodentate ligand, the affinity of phosphoryl for UO_2~(2+)is stronger than that of carbonyl, and CPO coordinates with UO_2~(2+)through the phosphoryl oxygen atom. When CPO serves as a bidentate ligand, both the phosphoryl and carbonyl oxygen atoms connect to UO_2~(2+), and the U–O(carbonyl) bond plays a more important role than the U–O(phosphoryl) bond in the interaction between UO_2~(2+)and CPO. This paradox may be caused by the significant charge transfer from the U–O(carbonyl) p bond orbital to the C–N σ antibond orbital of the bidentate CPO. The NH spacer between the phosphoryl and carbonyl groups could ensure the delocalization of the electron system of the molecule. The bidentate binding motif is favored by entropy and opposed by enthalpy, while the monodentate binding motif is favored by enthalpy and opposed by entropy. Ultimately, the bidentate binding motif is more favorable than the monodentate one. As expected, the interaction between UO_2~(2+)and the deprotonated CPO is stronger than that between UO_2~(2+)and the neutral CPO. Comparing the interaction between UO_2~(2+)and CPO with that between UO_2~(2+)and Nphenylcarbamoylphosphoramidic acid(Ph CPO), formed by replacing one hydrogen atom from the terminal nitrogen atom of CPO with a phenyl group, the phenyl substituent at the terminal nitrogen atom of Ph CPO shows a slightly negative effect on the interaction between UO_2~(2+)and Ph CPO.     

一种新的故障链路识别算法RPI

针对目前大多数故障链路识别算法不能兼顾良好稳定性和低计算复杂性的问题,该文提出一种基于参考路径的故障链路识别算法RPI(Reference Path based lossy link Identification algorithm)。该算法根据路径间的性能差异,从经过同一链路的所有路径中选取一部分作为该链路的参考路径,然后采用启发式方法根据参考路径间的性能相关性识别该链路的状态。相较已有算法,RPI更充分地利用了测量数据的可用信息,具有更好的稳定性,同时启发式估计策略保证了算法的低计算复杂性。仿真结果表明RPI能够在多种网络场景下较同类算法更精确地识别出故障链路。     

真空感应炉熔炼Inconel713C氧氮含量控制工艺

研究了150 kg真空感应炉熔炼Inconel713C氧、氮含量控制工艺,设计了四种不同的熔炼方案,研究了熔化时间、精炼前碳的加入量、精炼参数等因素对Inconel713C氧、氮含量的影响。结果表明,将0.14%/(质量比).脱氧剂碳随原料加入炉内,熔化时间为80 min,全熔后在钢液中加入0.03%.脱氧剂碳,在精炼温度为1450℃下精炼25 min,精炼后钢液中氧、氮含量均可控制在10×10^-6以内。     

政府工程中工程项目管理委托选择标准研究

我国政府工程中正在探索推行"代建制'即工程项目管理委托模式,但其中对项目管理单位的选择还没有统一详细的标准.在皿Ic推荐的工程咨询单位选择标准基础之上,通过分析我国"代建制"实施较早的上海、北京、武汉、重庆、深圳等城市的选择标准,构建了适合我国现状的选择标准体系.     

北京工业大学体育馆空调系统设计

介绍了该体育馆空调系统的冷热源、空调方案、气流组织、水系统、防排烟系统等的设计。通过采用合理的送排风气流组织设计,体育馆内温度场、速度场达到了很好的使用要求;空调冷热源采用地源热泵制冷机,达到了节能的目的。     

上海浦东国际机场大水灰比三轴深层搅拌桩配合比试验研究

上海浦东国际机场二期地基土具有典型软土特性,地基处理非常重要.试验段施工证明,采用常规两轴搅拌桩施工工艺无法满足地基处理要求.因此,采用SMW工法桩的二轴水泥土搅拌桩机进行加固施工.为获得大水灰比深层搅拌桩稳定施工工艺、确保工程质量,深层搅拌桩配合比成为能否实现这一目标的关键技术.依据配合比确定的原理,对室内配合比试验的研究方案、方法、确定程序进行研究,解决了规范条件不适用情况下,大水灰比水泥土深层搅拌法的配合比试验问题,为某机场深层搅拌桩复合地基施工及验收提供依据.     

蒸汽发生器泄漏率监测仪修复经验总结

目前压水堆核电站使用辐射监测仪对主蒸汽管道中的N-16核素浓度进行连续监测,由于蒸汽发生器泄漏监测仪长期工作在高温高湿环境下,普遍存在故障率偏高的问题,影响到了核电站相关系统的正常运行。从6台SGLM201型蒸汽发生器泄漏率监测仪的故障诊断、故障原因分析、修复技术研究等方面入手,分析了总γ计数异常闪发故障、稳峰异常故障...     

脉冲电源印染污水处理的负载特性分析

基于电化学理论方法和参数拟合,对脉冲电源作用下印染污水处理的电解槽负载进行建模.先在电化学原理的基础上进行理论建模,采用电化学阻抗谱方法,得出电解槽负载的等效电路模型.通过测量负载的阶跃响应曲线并进行参数拟合,对实际工程应用中的等效电路模型进行定量分析,得出模型中各个参数的具体值.最后按照得出的参数值进行仿真,并与实验结果相比较,比较结果证明了等效电路的合理性.     

数字图书馆多媒体专题文献动态网站建设

介绍在数字图书馆建设中应用JSP技术和java组件技术建立多媒体专题文献网站的意义、方案、相关技术和一个实例。