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基于暂态特征突变量的配电网故障选线方法研究
The Research of a Method to Select Fault Line for Power Distribution Networks Based on Transient Quantity Mutation
 [PDF]

,
Advances in Energy and Power Engineering (AEPE) , 2015, DOI: 10.12677/AEPE.2015.35022
Abstract:
本文对于配电网络常见的单相接地故障,提出了一种基于暂态特征突变量的综合选线方法。首先,对故障后各线路的暂态零序电流进行小波分解;然后,由小波分解系数求得低频能量占总能量的百分比来区分为强故障或弱故障;最后,在强故障情况下采用小波包系数极性法,在弱故障情况下采用暂态零序能量法来选择故障线路。通过MATLAB进行了大量的仿真验证,结果表明该方法具有很好的选线能力,即使发生母线故障、相电压过零故障,高阻接地故障时也能正确选线。
For the single-phase grounding fault in the power distribution, a method to select fault line was proposed in the paper. Firstly, wavelet decomposition was used to transient zero-sequence current of each line after fault; then, the percentage of the low frequency energy to the total energy, which were calculated by the wavelet coefficients, was used to distinguish strong or weak fault; finally, the fault line was selected by comparing the polarities of the wavelet packet decomposition coefficient in the strong fault situation, but comparing the transient zero-sequence energy in the weak fault situation. The MATLAB simulation results show that the method is proposed has good ability to carry out the fault line. The criterion can keep the high reliability when the circuit is bus-bar, high resistance or voltage zero grounding.
不同放牧率对冷蒿小禾草草原土壤微生物数量和生物量的影响

草地学报 , 1999, DOI: 10.11733/j.issn.1007-0435.1999.03.008
Abstract: 以围栏轮牧方式研究不同放牧率对退化草原土壤微生物的影响。结果表明,围栏及适度放牧四年后使土壤微生物的数量显著提高(P<0.01),有利于退化草原的逐步恢复。与对照区比较,放牧区微生物各类群的数量均呈减少趋势,并与土壤有机碳变化密切相关(P<0.01)。九年后,在4羊/ha区的微生物量-C高于对照区,而在1.33和6.67只羊/ha区则有所降低。长期中牧(4只羊/ha)对土壤微生物总数无显著影响。
我国城镇化发展与环境污染的关系研究—基于31个省市Panel Data变系数模型与VAR模型的实证分析
Analysis of the Relationship between Chinese Urbanization and Environmental Pollution —An Empirical Study Based on Panel Data Model with Variable Coefficients and VAR Model of 31 Provinces and Cities
 [PDF]

, 兰海强, 干文
Statistics and Applications (SA) , 2014, DOI: 10.12677/SA.2014.33016
Abstract:
“积极稳妥地推进城镇化”自纳入“十五”规划以来,已成为我国一项基本发展战略。而随着生活水平的日益提高,人们对环境问题也越来越关注。因此,研究城镇化发展与环境污染的关系有重要意义。本文首先利用环境类指标构造环境污染指数,并对历年城镇化率的统计口径进行了修正,然后用描述性统计方法对我国城镇化发展与环境污染的关系进行了特征研究,最后利用Panel Data变系数模型和VAR模型从静态和动态角度对城镇化发展与环境污染的关系进行了深入探讨。研究结果表明,我国大多数省市处于倒U型曲线的左半段,即城镇化的发展带来了一定的环境污染问题。然而对于少数省市(如北京、上海和天津等),城镇化发展会改善环境状况。针对这些结论,提出了相应的对策建议。
Since the 10th Five-Year Plan of China, “actively yet prudently moving forward with urbanization” has been a fundamental development strategy in our country. With rising living standards, people increasingly concern about environmental issues. Therefore, it is quite meaningful to study the relationship between urbanization and environmental pollution. First of all, we use environmental indicators to structure environmental pollution index and conduct a statistical correction on the urbanization rate over the years. Then, features of the relationship between Chinese urbanization and environmental pollution are studied by descriptive statistics. Finally, by using varied coefficients Panel Data model and VAR model, we deeply discuss the relationship between the de-velopment of urbanization and environmental pollution from the perspective of both static and dynamic. The result shows that, the majority of our provinces in the left sections of the inverted U shaped curve, namely the development of urbanization has brought some environmental problems. While for few provinces (such as Beijing, Shanghai and Tianjin etc.), urbanization will improve the environment. According to these conclusions, the paper puts forward the corresponding development suggestions.

CHARACTERISTICS AND FUNCTION OF DECOMPOSER SUBSYSTEM IN LEYMUS CHINESIS STEPPE
羊草草原分解者亚系统的特性及作用

ZhaoJi,

生态学报 , 1995,
Abstract: he present paper studied the charactristics and functions of decomposer subsystem ofLeymus chinensis steppe in Inner Mongolia. The decompositions of litter of Leymus chinensis plant and materials in different phenological periods were determined by net-bag method. Themain results were as follows:1. The biomass of microorganisms and the activities of enzymes (protease and invertase)on the surface of the residues of young plants were higher than thatof old plants. The decomposing rate of young plants mate...
通过腹腔门进行猪羊生殖生物学非手术连续观察和采集

科学通报 , 1991,
Abstract: 动物对内脏痛疼刺激是很不敏感的。从而对正常清醒动物腹腔器官,进行触创较大的生物学观察和采集,有了可能。我们从1982年底开始,在猪腹壁切口安拉链,制备成持久性创口,腹腔门,给这种可能的兑现打
γ-氨基丁酸注于大脑皮层和侧脑室内对家兔条件反射活动的影响
梅镇彤,
科学通报 , 1960,
Abstract: 1950年Roberts等和Awapara等证明在哺乳动物的脑髓中含有大量的γ-氨基丁酸(以下简称GABA)。1953年Florey观察到哺乳类动物脑髓的抽提物中含有抑制龙虾伸展受纳器神经原放电的物质,并命名为抑制因素(FactorI)。1956年Florey等又进一步指出,GABA是抑制因素的主要成分。于是这一个在脑髓中大量存在、而又具有特殊生理效应的物质就引起了神经生理学家广泛的兴趣。
关于传统的跳角測定方法存在问题的试验分析

兵工学报 , 1985,
Abstract: ?本文在对大、小口径火炮跳角试验数据整理分析的基础上发现:同一发弹,按传统跳角定义及其测试方法所得的跳角值随靶距不同而变化很大,且同一发弹在不同距离上的最大最小跳角差|△γ|与起始章动幅值成正比。本文对产生此现象的原因作了解释和分析。为纠正传统跳角定义上的缺陷而提出新的跳角定义为:射前炮(枪)身轴线与射后弹道起始段螺线弹道轴线间的夹角。
径向基SVM核参数混沌优化及工程应用

安徽大学学报(自然科学版) , 2007,
Abstract:
盛夏南疆降水过程与南亚高压

气象 , 1978, DOI: 10.7519/j.issn.1000-0526.1978.09.006
Abstract:
基于分子动力学模拟研究温度致Aβ42蛋白构象变化
Conformation Transformation of Aβ42 Protein under Different Temperature by Molecular Dynamics Simulations
 [PDF]

付静, 立岭,
Hans Journal of Biomedicine (HJBM) , 2013, DOI: 10.12677/HJBM.2013.31001
Abstract:
基于分子动力学模拟方法研究了不同温度对Aβ42蛋白结构的影响。模拟选用GROMACS软件包和GROMOS 43A1分子力场,在300 K、340 K和380 K下分别进行60 ns的分子动力学模拟。通过计算原子均方根涨落、回旋半径、二级结构形成几率等参数,分析了Aβ42蛋白结构的稳定性、二级结构及三级结构形成。研究发现:该蛋白在三种不同温度下,都没有稳定结构,表现出固有无序特征,温度会导致结构特征发生显著变化;在高温(380 K)时,会产生α螺旋向β折叠转换的趋势。
The temperature-induced conformation changes of Aβ42 protein were studied by molecular dynamics simu-lation. The three independent molecular dynamics simulations of Aβ42 protein at different temperatures 300 K, 340 K and 380 K, were performed using the GROMACS software package and GROMOS 43A1 force field, respectively. Each simulation was run for 60 ns. Based on the simulations, we analyzed the conformation changes of Aβ42 protein and the formation of its secondary structure and tertiary structure. The results indicated that Aβ42 protein has no stable structure and it has the characters of intrinsically disorder proteins at the different temperatures. It also shows that the structure of Aβ42 protein change obviously with different temperature. In addition, there is a change tendency from α-helix to β-sheet at 380 K.
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