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基于电压稳定临界状态分区的无功源配置 被引量:2
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作者 李玮 方鸽飞 《机电工程》 CAS 2011年第8期1025-1027,1032,共4页
为解决无功功率不能远距离传输的问题,提出了在大电网电压稳定分区的基础上合理地配置无功源。首先,将分区点设定为电压稳定临界状态点,采用聚类分析的方法计算分区结果。然后,利用节点的无功裕度在电网拓扑中的分布,将各分区内无功裕... 为解决无功功率不能远距离传输的问题,提出了在大电网电压稳定分区的基础上合理地配置无功源。首先,将分区点设定为电压稳定临界状态点,采用聚类分析的方法计算分区结果。然后,利用节点的无功裕度在电网拓扑中的分布,将各分区内无功裕度最小的节点作为无功源配置点。最后,采用Matlab软件对IEEE30节点系统进行了仿真,分别将所提方法与"未分区、直接按照无功裕度大小配置"的方法作比较。结果表明,该方法在应对临界状态时系统的无功控制更加可靠,故其对于提高系统电压的稳定性效果更好。 展开更多
关键词 无功裕度 电压稳定临界状态分区 电压稳定
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乌鲁木齐市小流域山洪灾害临界雨量分区及防治区划研究 被引量:2
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作者 宾建华 窦新英 《水土保持研究》 CSCD 北大核心 2005年第5期252-255,共4页
分析了乌鲁木齐市以小流域为单元,在复杂的地形、地貌和不同的气候背景下,进行临界雨量的分区,并相应提出在阿拉沟流域取点与现有的气象站点构成5个代表点,运用泰森多边形法进行小流域分区,可达到科学、合理的效果,进而为山洪灾害防治... 分析了乌鲁木齐市以小流域为单元,在复杂的地形、地貌和不同的气候背景下,进行临界雨量的分区,并相应提出在阿拉沟流域取点与现有的气象站点构成5个代表点,运用泰森多边形法进行小流域分区,可达到科学、合理的效果,进而为山洪灾害防治规划研究提供了可靠的技术参数。 展开更多
关键词 小流域 山洪灾害 临界雨量分区 重点防治区划
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变风量多分区空调系统新风量计算 被引量:7
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作者 叶大法 杨国荣 《暖通空调》 北大核心 2008年第6期8-13,共6页
介绍了变风量多分区系统的区域新风需求、新风分布、通风效率和单/双通道多分区循环系统,借鉴ANSI/ASHRAE标准62.1—2004提出的系统新风量计算方法给出了变风量多分区空调系统的新风量计算方法。该方法有助于在新风节能方面拓展设计思路。
关键词 通风分区 呼吸区 空气分布效率 单/双通道多分区系统 区域/系统通风效率 临界分区
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Thermodynamics of Third Order Lovelock Anti-de Sitter Black Holes Revisited
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作者 ZOU De-Cheng YUE Rui-Hong YANG Zhan-Ying 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第3期449-456,共8页
We compute the mass and temperature of third order Lovelock black holes with negative Gauss-Bonnet coefficient a2 〈 0 in anti-de Sitter space and perform the stability analysis of topological black holes. When k = -1... We compute the mass and temperature of third order Lovelock black holes with negative Gauss-Bonnet coefficient a2 〈 0 in anti-de Sitter space and perform the stability analysis of topological black holes. When k = -1, the third order Lovelock black holes are thermodynamically stable for the whole range r+. When k = 1, we found that the black hole has an intermediate unstable phase for D = 7. In eight dimensional spacetimes, however, a new phase of thermodynamically unstable small black holes appears if the coefficient a is under a critical value. For D ≥ 9, black holes have similar the distributions of thermodynamically stable regions to the case where the coefficient & is under a critical value for D = 8. It is worth to mention that all the thermodynamic and conserved quantities of the black holes with fiat horizon do not depend on the Loveloek coefficients and are the same as those of black holes in general gravity. 展开更多
关键词 third order Lovelock gravity AdS space THERMODYNAMICS
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Role of hydro-geochemical functions on karst critical zone hydrology for sustainability of water resources and ecology in Southwest China 被引量:1
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作者 Xi Chen Yimeng Sun Richao Huang 《Acta Geochimica》 EI CAS CSCD 2017年第3期494-497,共4页
Focusing on sustainability of water resources and ecology in the complex karst critical zone, we illustrated functions of the hydro-geochemical analysis on hydrology from the aspects of connection and interaction amon... Focusing on sustainability of water resources and ecology in the complex karst critical zone, we illustrated functions of the hydro-geochemical analysis on hydrology from the aspects of connection and interaction among hydrology–vegetation–soils/rock fractures along the karst subsurface profile. We reviewed isotopic and geochemical interpretations on tracing water sources for plant uptake, quantifying watershed outlet flow composition and residence times, and evaluating long-term evolution among climate–landscape–hydrology in the karst critical zone. In this paper, the application of the hydro-geochemical analysis on the above aspects in the karst areas of southwest China was summarized. 展开更多
关键词 Hydro-geochemical analysis Karst critical zone Water resources Vegetation Southwest China
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The Effect on Sporadic-E of Quasi-Biennial Oscillation
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作者 Ramazan Atici Selcuk Sagir 《Journal of Physical Science and Application》 2016年第2期10-17,共8页
In this study, the relationship between the QBO (quasi-biennial oscillation), which is seen at the equatorial stratosphere, and critical frequency of layer (Es) sporadically observed at the ionospheric E region wa... In this study, the relationship between the QBO (quasi-biennial oscillation), which is seen at the equatorial stratosphere, and critical frequency of layer (Es) sporadically observed at the ionospheric E region was analyzed by using multiple regression model. For this analysis, Es layer critical frequency (foEs) obtained from four different stations at equatorial region and QBO measured at 10 hPa altitude values were used. The positive relationship between foEs and QBO was observed at all stations. An increase of 1 m/s at QBO leads to an increase of 0.01 Mhz, 0.02 Mhz, 0.02 Mhz and 0.01 Mhz (Jicamarca, Ascension, Manila and Kwajalein) on foEs, respectively. Expect for Manila station, westerly phase of QBO has greater effect on foEs compared to easterly phase of QBO at all other stations. It is seen that the changes occurred on foEs can be explained by the QBO at rates 47%, 46%, 32% and 44% for Jicamarca, Ascension, Manila and Kwajalein stations, respectively. 展开更多
关键词 Sporadic E QBO multiple regression model ionospheric E-Region.
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