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111.
         下载免费PDF全文
This paper proposes a new estimation method to determine arbitrary circuit parameters for the harmonic analysis of a distribution network. Harmonic analysis is important in maintaining electric power quality. An interesting phenomenon, a temporary cut‐down of the harmonic voltage level at dawn, even if demand is slightly increasing at this time, is often observed in actual power systems. This paper proposes to utilize observations of this phenomenon to estimate circuit parameters. In addition, it is claimed that a detailed equivalent circuit is preferable to a conventional simplified equivalent circuit for explaining the phenomenon. This paper also discusses the usefulness of the Harmonic Characteristics Curve, which is proposed in this paper as a new concept, at the secondary winding of the distribution transformer, and the correlation of PQ, the monitored values of the active and reactive power at the secondary winding of distribution transformer. This correlation should determine the equivalent fundamental frequency admittance of the shunt capacitors installed for distribution lines. © 2014 Wiley Periodicals, Inc. Electr Eng Jpn, 187(1): 16–23, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22451  相似文献   
112.
基于遗传算法的高压长线路双端故障测距研究   总被引:2,自引:1,他引:2  
为提高高压长线路故障定位的准确度,提出了一种基于遗传算法的故障定位新方法。该方法基于线路分布参数模型,按照故障线路两端沿线向对端推得的故障点电压幅值相等的原则列写故障测距方程,并通过相量法对电压分布函数的单调性进行分析,得到伪根判别法则的数学表达式;引入遗传算法求解故障测距方程,采用群体搜索和多父体重组策略,自适应和容错能力强且能够保证解群搜索的遍历性和快速性;在一次搜索中算法可求得故障距离的多个解,有利于伪根的判别。ATP仿真结果和实际应用证明了该方法不受过渡阻抗、故障类型及不同步角的影响,计算速度快且精确度高。  相似文献   
113.
ATP系统的粗跟踪平台外框架对内框架的耦合作用以及内框架自身的不平衡所引起的加速度干扰是影响空间光通信系统光信号跟踪性能的重要因素。针对方位跟踪通道中的内框架系统结构,提出了应用一种混合自适应控制方法,该方法在设计自适应控制器时采用离散与连续相结合的方法,并将耦合作用和加速度干扰转换为对象的未建模动态进行处理。最终的仿真结果表明,被控对象在具有未建模动态和干扰的情况下,采用混合自适应控制算法能够获得较高的跟踪精度。  相似文献   
114.
在分析超高压电网中发生各种故障类型模分量的特征基础上,通过提取信号暂态数据窗能量谱,提出了一种利用数学形态学梯度提取暂态电流故障特征进而识别故障类型的新方案.通过一个典型500 kV双端系统进行的大量ATP仿真计算表明,在不同位置、过渡电阻、故障初始角的情况下发生各种故障均能正确、快速地识别故障相,与传统算法相比计算量较少,且具有更高的灵敏度和更快的故障响应速度.  相似文献   
115.
无人机激光无线能量传输及跟踪瞄准方法研究   总被引:1,自引:0,他引:1       下载免费PDF全文
本文介绍了无人机的特点与发展趋势,针对小型无人机能量供给不足的问题,阐述了激光无线能量传输的现状,在此基础上总结了无人机激光无线能量传输的系统结构,分析了无人机激光无线能量传输系统的效率及影响因素,并提出了一种基于协作目标的捕获跟踪瞄准方法。  相似文献   
116.
酶法转化谷氨酰胺   总被引:7,自引:0,他引:7  
高产谷氨酰胺的谷氨酸棒杆菌经酶解和超声波处理后,释放出高活性的谷氨酰胺合成酶(Glutamine synthetase,简称GS). GS的胞外催化反应受各种反应条件和因素的影响. 通过单因子实验、响应面实验和正交实验发现,反应混合物中最显著的影响是腺三膦(ATP),当ATP浓度在40~50 mmol/L时,催化作用达到最高;同时酶量对反应也有较大的影响. 研究了粗酶液在细胞外反应时各种因素对谷氨酸棒杆菌GS催化作用的影响,获得了体外酶催化反应的适宜条件,最高转化产生的谷氨酰胺可达7.1 g/L,转化率达到94.8%.  相似文献   
117.
Following major advances in the field of medicinal chemistry, novel drugs can now be designed systematically, instead of relying on old trial and error approaches. Current drug design strategies can be classified as being either ligand- or structure-based depending on the design process. In this paper, by describing the search for an ATP synthase inhibitor, we review two frequently used approaches in ligand-based drug design: The pharmacophore model and the quantitative structure-activity relationship (QSAR) method. Moreover, since ATP synthase ligands are potentially useful drugs in cancer therapy, pharmacophore models were constructed to pave the way for novel inhibitor designs.  相似文献   
118.
艾珂 《天津冶金》2004,(1):35-38
列车超速防护(ATP)系统是城市轨道交通自动控制的重要组成部分。以ATP为对象的仿真系统对于ATP系统的研制、检验以及展示具有十分重要的意义。文章介绍了国内外ATP系统的发展状况和国产铁路ATP仿真系统的基本组成及其设计指导思想。  相似文献   
119.
    
ABSTRACT:  The study was carried out to evaluate the effects of gamma-irradiation alone or in combination with oregano essential oil on murein composition of  Staphylococcus aureus  and on the intracellular and extracellular concentration of ATP. The bacterial strain was treated with 3 irradiation doses: 1.2 kGy to induce cell damage, 2.9 kGy to obtain a viable but nonculturable state, and 3.5 kGy to cause cell death. Oregano essential oil was used at 0.010% and 0.013% (w/v), which is the minimum inhibitory concentration (MIC). All treatments had a significant effect ( P  ≤ 0.05) on the murein composition, although some muropeptides did not seem to be affected by the treatment. Each treatment influenced differently the relative percentage and number of muropeptides. There was a significant ( P  ≤ 0.05) correlation between the reduction of intracellular ATP and increase in extracellular ATP following treatment of the cells with oregano oil. The reduction of intracellular ATP was even more important when essential oil was combined with irradiation. Also, irradiation alone of  S. aureus  induced a significant decrease ( P  ≤ 0.05) of the internal ATP and a significant increase ( P  ≤ 0.05) of the external ATP. However, no significant difference ( P  > 0.05) was observed in ATP concentrations between different radiation doses. Transmission electron microscopic observation revealed that oregano oil and irradiation have an effect on cell wall structure.  相似文献   
120.
    
By means of gene disruption analyses, Saccharomyces cerevisiae strain YPH499 was shown to have two, and only two, copies of ATP3 that encodes the gamma-subunit of H+-dependent ATP synthase and locates on the right arm of chromosome II. Linkage analyses of the two distinguishably marked copies of ATP3 indicated that the distance between them was about 43 cM. Since YBR030W, an ORF proximal to ATP3 by a distance of 17 kbp, was also found to be duplicated, we marked them with two distinguishable nutritional markers, which were also distinguishable from those used for marking the two copies of ATP3, and achieved four-point linkage analyses; CEN2 marked with an appropriate nutritional marker gene was included as a reference point. And, the following linkage map was deduced: CEN2- [11 cM]-YBR030Wa- [8 cM]-ATP3a-[47 cM]-ATP3b- [55 cM]-YBR030Wb. From this map, we suspected that a segment spanning at least YBR030W-ATP3 would be inversely duplicated on the right arm of chromosome II. We then carried out chromosome fragmentation analyses, using several laboratory strains including YPH499, and obtained data in accord with our speculation for all strains, although the distance between the two copies of ATP3 varied from 48 kbp to 192 kbp among the strains examined.  相似文献   
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