电网电容电流的外加信号测量法

介绍了一种新的电网电容电流外加信号单频测量法,弥补了相位法、幅值法、幅值相位法在电力电网中测量的缺陷与不足。     

Study on Pollution Flashover Performance of Short Samples of Composite Insulators Intended for /spl plusmn/800 kV UHV DC

Based on the artificial pollution tests, the effects of pollution and high altitude on the flashover performance of short samples of five kinds of UHV/EHV dc composite long rod insulators are analyzed. The exponent characterizing the influence of salt deposit density on the flashover voltage is related with the profile and the material of the insulator shed. The values of the samples' exponents vary between 0.24 and 0.30, which are smaller than those of porcelain or glass cap-and-pin insulators, namely, the influence of the pollution on the composite long rod insulators is less, relatively. Thus, the composite insulators have certain advantages in severe pollution regions. The best ratio of the leakage distance to the arcing distance is about 3.35. The exponent characterizing the influence of air pressure on the flashover voltage is related with the profile and the material of the insulator shed and the pollution severity, the values of the samples' exponents vary between 0.6 and 0.8, which are larger than those of porcelain or glass cap-and-pin insulators. Therefore, the dc composite insulator used in high altitude regions should have enough arcing distance. Based on the test results, if insulator sample Type E is selected for the plusmn800 kV UHV dc transmission lines, the basic arcing distance should be no less than 8.16 m and the basic leakage distance no less than 30.2 m.     

基于信道性能的频谱分配算法

频谱分配是认知无线电的关键技术之一,各授权信道的可用概率与授权用户的到达率以及次用户业务量传送时间有关,并且实际效益还与该信道的衰落因子相关。提出了基于以上信道性能的CSGC频谱分配算法,该算法通过优先分配相对信道利用率高、信道衰落小的信道,达到最大化实际总效益的目的。仿真结果表明,该算法是有效的。     

受弯构件经环氧注浆裂缝修补受力性能研究

通过对2根经环氧注浆裂缝修补后的钢筋混凝土梁进行由下向上两点加载试验,研究对比修补前后裂缝开展宽度、位置及荷载-挠度曲线等的变化规律.结果表明,环氧树脂因良好的渗透性,不仅使经环氧树脂修补后的裂缝及周边混凝土得到有效加强,实现了"被粘物破坏"机制;而且可显著提高钢筋混凝土梁的初裂荷载,增强其抗弯刚度和抗裂性,对受力裂缝有着良好的修补效果.同时,基于现场注浆实际操作时间,引入折减系数,提出了修正后的计算注浆扩散半径公式.     

一种α稳定分布下的变抽头长度LMP算法

针对无法事先知道滤波器抽头长度,且系统中存在“稳定分布噪声的情况,提出了一种α稳定分布背景下的变抽头长度自适应算法,采用3个并行的滤波器,比较数据段内其平均P阶误差大小,每K点数据段更新一次抽头长度,数据段内滤波器权值采用LMP算法调整。算法仿真表明,算法在不同特征指数的α稳定分布下都具有很强的韧性,能自适应调整到最优抽头长度,达到最优抽头长度的LMP算法的稳态误差。     

丝胶热性能的研究

本文介绍了对丝胶在各种温度下的热失重,碳、氢、氮各元素相对含量的变化,氨基酸组成的改变,以及在氮气保护下经不同温度处理后的丝胶及其丝胶碳化物红外光谱行为的变化所进行的研究,定量、半定量地探索了丝胶分子组成和结构的改变及构成丝胶的各个氨基酸的热稳定性。根据热稳定性不同,可将组成丝胶蛋白质的氨基酸分成热不稳定、次不稳定和热稳定三类。氨基酸的热稳定性与其酸碱性无关。     

基于碳交易市场下的电力企业碳减排决策研究

中国CO2排放量巨大,其中电力企业的CO2排放量占全国总排放量的50%以上。在碳交易市场背景下,电力企业需要在拍卖购买碳配额进行减排与自主更新进行减排中作出抉择。基于成本效益法对发电企业的低碳成本进行了综合分析,将通过优化后所减少的CO2排放量作为收益,在碳排放交易市场的背景下将碳减排的经济效益进行量化,并通过与碳排放权交易市场的碳价格进行比较,从而得出火电企业所应作出的最佳决策。如结果所示,在一定条件下,如果企业进行技术更新后可以减排10%、20%、30%的电力生产CO2排放量,则火电企业所作出的碳减排决策分界点的拍卖比例分别为54%、27%与18%。     

Addition of Adipose-Derived Stem Cells to Mesenchymal Stem Cell Sheets Improves Bone Formation at an Ectopic Site

To determine the effect of adipose-derived stem cells (ADSCs) added to bone marrow-derived mesenchymal stem cell (MSC) sheets on bone formation at an ectopic site. We isolated MSCs and ADSCs from the same rabbits. We then prepared MSC sheets for implantation with or without ADSCs subcutaneously in the backs of severe combined immunodeficiency (SCID) mice. We assessed bone formation at eight weeks after implantation by micro-computed tomography and histological analysis. In osteogenic medium, MSCs grew to form multilayer sheets containing many calcium nodules. MSC sheets without ADSCs formed bone-like tissue; although neo-bone and cartilage-like tissues were sparse and unevenly distributed by eight weeks after implantation. In comparison, MSC sheets with ADSCs promoted better bone regeneration as evidenced by the greater density of bone, increased mineral deposition, obvious formation of blood vessels, large number of interconnected ossified trabeculae and woven bone structures, and greater bone volume/total volume within the composite constructs. Our results indicate that although sheets of only MSCs have the potential to form tissue engineered bone at an ectopic site, the addition of ADSCs can significantly increase the osteogenic potential of MSC sheets. Thus, the combination of MSC sheets with ADSCs may be regarded as a promising therapeutic strategy to stimulate bone regeneration.     

经济型高强钢筋的生产技术

新一代TMCP技术就是以超快速冷却技术为核心的NG-TMCP技术。采用该技术,可大批量生产低成本的HRB400热轧带肋钢筋,其主要规格为16、18、20和25mm,且各项性能指标符合国标GB1499.2的规定。采用该技术,可降低钢筋中的钒含量,使吨钢减少成本40元。     

PL2101电力线载波芯片I2C通信的实现

简要地介绍了电力线载波芯片PL2101、I^2C串行通信的基本原理以及两之间通信与程序的实现。