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21.
With the growing size and complexity of power systems, system analysis—such as transients calculation—takes much time. Hence, fast calculation methods are required. Although parallel processing is a hopeful method, there have been difficulties in the parallel solution of linear equations which appear in power-flow calculations by the Newton-Raphson method. This paper aims at the fast calculation of the power-flow problem by means of parallel processing. In order to improve the suitability to the parallel solution of the differential equation in transients calculation, we assume the use of a direct-mapping parallel processing machine to map directly the network of a power system onto a network of processors. Under this assumption, we propose a new parallel-processing-oriented method in which the linear equation is solved by linear iterations between nodes with Aitken acceleration. We simulate the method on three model power systems and compare this Parallel Iterative Method (PIN) with a Parallel Direct Method (PDM) which uses the banded matrix according to the number of operations required. As a result, we can expect that PIM may solve linear equations faster than PDM with m processors, although the PIM might be inferior to the PDM with m × m processors, where m denotes the half-band width of the banded matrix. 相似文献
22.
Li2O在保护渣中的作用 总被引:7,自引:0,他引:7
采用在不同玻璃性的两种基渣中加入Li2O为研究Li2O对保护渣粘度,熔化温度及玻璃性能的影响,并对Li2O改善保护渣玻璃性的机理进行了探讨,提出了寻找高速连铸保护渣中Li2O的代用物的一种方法。 相似文献
23.
为了改善M2高速钢共晶碳化物的分布,本文利用小凝固试样变质的方法研究了Ti,N和Mg对M2高速钢凝固组织和硬度的影响。试验结果表明,加入Ti或Ti-N后,共晶碳化物形态和分布有很大改善,而加入Ti-N后对凝固组织有轻微的细化作用,但只添加Ti不补碳时,钢的淬火硬度和回火硬度均下降;加入适量的Mg可以使片状的M2C型共晶碳化物转为鱼骨状的M6C型共晶碳化物,使其分布有所改善,Ti和Mg复合加入可以明 相似文献
24.
有机盐聚合醇氯化钾钻井液的应用 总被引:5,自引:2,他引:3
霍尔果斯背斜构造极其复杂,内应力极高,地层倾角大,断层、破碎带多,并存在高低压互层;安集海河组的灰绿色软泥岩水化严重并具有粘弹塑性.该区块重点探井霍003井三开、四开井段选用有机盐聚合醇氯化钾钻井液,同时为保证钻井液在高密度下(2.55 g/cm^3)具有好的流变性,使用活化铁矿粉、活化重晶石加重.应用结果表明,由于采用了强抑制和多元封堵的措施,该钻井液具有良好的流变性和较强的携带能力,钻进中曾携带出重2.8 kg和5.1kg的大掉块;滤失量低,泥饼质量好,封堵能力强,造壁能力强,减轻了井下阻卡程度;有良好的储层保护能力;在室内研究的基础上,经过现场合理使用和维护钻井液,霍003井提高了机械钻速,缩短了钻井周期,井身质量优于邻井.指出在高密度下,未选出适合有机盐聚合醇氯化钾钻井液的稀释剂,钻井液流动性较差. 相似文献
25.
26.
High speedsteel (HSS) ,ischaracterizedbyex cellenthardness ,wearresistance ,and goodredhardness .Recently ,HSSisappliedtomanufacturehotrollingrollstoproducestripsofgoodshapeandsmallcrownwithextendedrollservicelife[1,2 ] .TheHSSisappliedtomanufacturerollcollarfor… 相似文献
27.
通过对牙轮钻、轴压、钻头速度、排碴风量、排碴风压的论述得出了如何调定牙轮钻的参数,为以后我矿牙轮钻在生产中获取最大经济效益积累了有益的资料。 相似文献
28.
Manual responses can be defined by differing response parameters. Any of them may generate a Simon effect. For all those response parameters, the same implementation of the Simon effect (in terms of subserving mechanism) is assumed. In 3 experiments, subjects had to respond with either fingers or sticks. Temporal properties of the Simon effect changed with response parameters relevant in a task. The Simon effect for manual responses decayed. For stick responses, in which the action goal differed from the anatomical mapping of the acting hand, a sustained Simon effect was observed. However, if the action goal for stick responses was not instrumental for selecting the correct response, the Simon effect decayed. The findings are consistent with the notion of different mechanisms involved in generating a Simon effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
29.
Herbert S. Bennett 《Journal of research of the National Institute of Standards and Technology》2007,112(4):209-221
In this paper, we present the theory for calculating Raman line shapes as functions of the Fermi energy and finite temperatures in zinc blende, n-type GaAs for donor densities between 1016 cm−3 and 1019 cm−3. Compared to other theories, this theory is unique in two respects: 1) the many-body effects are treated self-consistently and 2) the theory is valid at room temperature for arbitrary values of the ratio R = (Q2/α), where Q is the magnitude of the normalized wave vector and α is the normalized frequency used in the Raman measurements. These calculations solve the charge neutrality equation self-consistently for a two-band model of GaAs at 300 K that includes the effects of high carrier concentrations and dopant densities on the perturbed densities of states used to calculate the Fermi energy as a function of temperature. The results are then applied to obtain the carrier concentrations from Fermi energies in the context of line shapes in Raman spectra due to the coupling between longitudinal optical phonons and plasmons. Raman measurements have been proposed as a non-destructive method for wafer acceptance tests of carrier density in semiconductor epilayers. The interpretation of Raman spectra to determine the majority electron density in n-type semiconductors requires an interdisciplinary effort involving experiments, theory, and computer-based simulations and visualizations of the theoretical calculations. 相似文献
30.
The Karlsruhe Tritium Neutrino experiment (KATRIN) is going to use a very large electro-static tandem spectrometer to measure the electron spectrum from the tritium beta decay, where several kilometers of non-evaporable getter (NEG) strips (type ST707) are to be used to achieve the UHV requirements. Different geometrical configurations of the NEG strips have been studied by Monte Carlo simulations. It is shown that the resulting pumping speed of the getter pumps will allow to get a pressure below 10−11 mbar in the huge vessel with a volume of 1400 m3. By systematic assessment of the statistics of the pumping surfaces, it could be demonstrated that the design is sound. 相似文献