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CsEE Journal of Power and Energy systems 2021年第4期7卷 821-831页

作者： Yang liu Zehui Lin Kaishun Xiahou Yuqing Lin q.H.Wu school of Electric Power Engineering South China University of TechnologyGuangzhou 510640China

This paper proposes an equivalent Hamiltonian equations model for the modular multilevel converter-based high-voltage direct-current(MMC-HVDC)transmission system,and constructs an energy function for multi-machine power systems with MMC-HVDC transmission *** equivalent Hamiltonian equations model is verified to be able to track the power output dynamics of the full model of an MMC-HVDC transmission *** theoretical and numerical studies have been undertaken to validate that the energy function proposed for hybrid AC/DC systems satisfies the conditions of an energy *** work of this paper bridges the gap between the well-developed direct methods of transient stability analysis and power systems with MMC-HVDC transmission lines.

关键词： Energy function equivalent Hamiltonian equations model hybrid AC/DC power system MMC-HVDC transient stability

On Identical Problems of Natural Convection in Enclosures and Applications of the Identity Character

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Journal of Thermal science 1993年第2期2卷 116-125页

作者： Yang, M. Tao, W.q. Wang, q.W. Lui, s.s. Xi'an Jiaotong Univ Xi'an China

In this paper, a concept of 'identical problems' of natural convection in enclosures is presented. A pair of problems of natural convection in enclosures is said to be identical if they look different in appearance but with appropriate selection of coordinates and appropriate definition of dimensionless variables for each problem, they will have identical geometric configurations and identical dimensionless governing equations and related boundary conditions. The identical characteristics of a pair of problems of natural convection in enclosures with an internal isolated island are demonstrated via dimensionless mathematical formulation and flow visualization results. Numerical computations are performed and the predicted streamlines agree with the flow visualization results. A number of other possible pairs of identical problems are also presented. Applications of the identical character are provided and assumptions under which the identical problems may exist are discussed.

关键词： natural convection enclosure flow identical problems

The circadian clock affects starvation resistance through the pentose phosphate pathway in silkworm,Bombyx mori

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Insect science 2025年第1期32卷 55-68页

作者： Tai-Ming Dai Jian-Feng qiu Cheng Luo Wen-Zhao Cui Kai liu Jiang-Lan Li Ruji Peng Yang-Hu sima shi-qing Xu school of Life sciences Suzhou Medical College of Soochow UniversitySuzhouJiangsu ProvinceChina Institute of Agricultural Biotechnology&Ecology(IABE) Soochow UniversitySuzhouJiangsu ProvinceChina

Disruption of the circadian clock can affect starvation resistance,but the molecular mechanism is still ***,we found that starvation resistance was significantly reduced in the core gene BmPer deficient mutant silkworms(Per−/−),but the mutant's starvation resistance increased with larval *** natural physiological conditions,the weight of mutant 5th instar larvae was significantly increased compared to wild type,and the accumulation ability of triglycerides and glycogen in the fat bodies was ***,under starvation conditions,the weight consumption of mutant larvae was increased and cholesterol utilization was *** analysis showed that beta-oxidation was significantly upregulated under starvation conditions,fatty acid synthesis was inhibited,and the expression levels of genes related to mitochondrial function were significantly *** investigations revealed that the redox balance,which is closely related to mitochondrial metabolism,was altered in the fat bodies,the antioxidant level was increased,and the pentose phosphate pathway,the source of reducing power in cells,was *** findings suggest that one of the reasons for the increased energy burden observed in mutants is the need to maintain a more robust redox balance in metabolic *** necessitates the diversion of more glucose into the pentose phosphate pathway to ensure an adequate supply of reducing power.

关键词： Bombyx mori circadian clock oxidative stress pentose phosphate pathway starvationresistance

Constructing an Energy Function for Power systems with DFIGWT Generation Based on a synchronous-generator-mimicking Model

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CsEE Journal of Power and Energy systems 2022年第1期8卷 64-75页

作者： Yang liu Chenying Xu Zehui Lin Kaishun Xiahou q.H.Wu the school of Electric Power Engineering South China University of TechnologyGuangzhou 510640China

In this paper we construct an energy function for multi-machine power systems with doubly-fed induction generator-based wind turbine(DFIGWT)according to a synchronous-generator-mimicking(sGM)model of the *** sGM model is proposed to approximate the dynamics of a *** to the modelling of a synchronous generator(sG),the internal dynamics of a DFIGWT are also described with differential equations of newly constructed virtual rotor angle and internal electromotive force(EMF)in the sGM ***,the power flow of a DFIGWT is expressed by nonlinear functions of its virtual rotor angle and internal *** sGM model bridges the gap between the irregular and complex modelling of DFIGWTs and the well-developed energy function construction techniques for sG *** on the sGM model,a numerical energy function is constructed for power systems with DFIGWT *** theoretical analysis and numerical studies were undertaken to validate that the proposed energy function satisfies the necessary conditions for an energy function of a power system.

关键词： DFIGWT energy function multi-machine power systems synchronous-generator-mimicking model

Estimating Critical Clearing Time of Grid Faults Using DA of state-Reduction Model of Power systems

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CsEE Journal of Power and Energy systems 2024年第2期10卷 807-820页

作者： Yang liu Zhongyang Chen Huanjin Yao Lin Yi q.H.Wu school of Electric Power Engineering South China University of TechnologyGuangzhou 510640China China southern Power Grid Research Institute Guangzhou 510663China

This paper proposes a critical clearing time (CCT) estimation method by the domain of attraction (DA) of a state-reduction model of power systems using sum of squares (sOs) programming. By exploiting the property of the Jacobian matrix and the structure of the boundary of the DA, it is found the DA of the state-reduction model and that of the full model of a power system are topological isomorphism. There are one-to-one correspondence relationships between the number of equilibrium points, the type of equilibrium points, and solutions of the two system models. Based on these findings, an expanding interior algorithm is proposed with sOs programming to estimate the DA of the state-reduction model. state trajectories of the full model can be transformed to those of the state-reduction model by orthogonal or equiradius projection. In this way, CCT of a grid fault is estimated with the DA of the state-reduction model. The calculational burden of sOs programming in the DA estimation using the state-reduction model is rather small compared with using the full model. simulation results show the proposed expanding interior algorithm is able to provide a tight estimation of DA of power systems with higher accuracy and lower time costs.

关键词： Critical clearing time domain of attraction expanding interior algorithm state-reduction model sOs programming

ON THE BURN REsIsTANCE OF Ti-35V-15Cr-0.05C TITANIUM ALLOY

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Acta Metallurgica sinica(English Letters) 1998年第3期11卷 202-206页

作者： G.P.Li D.Li Y.Y.liu q.J.Wang s.X.Guan q.C.Li Inst of Metal Research The Chinese Acad of Sciences Shenyang China

The Ti-35V-15Cr-0.05C (wt% is a new nonburning titanium alloy. The test for alloy combustibility was carried out by using CO2 laser. A 430 watt and 6mm diameter laser spot impinges directly on the sample within normal atmospheric pressure and temperature. The results show that the ignition time of the nonburning titanium alloy is the longest in the eight examined titanium alloys, and is 3.5 times that of TC4 alloy. The ignition tempeerature of the nonburning alloy is 2991° C, and is higher than that of TC4 alloy by 1976°C. On the condition of high tempeerature and rich oxygen,the surface of alloy forms a melting layer which plays roles of oxygen insulation, heat insulation and burning products insulation. This is the mechanism of combustion resistance.

关键词： Ti-35V-15Cr-0.05C (wt%) nonburning titanium alloy combustion resistance

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不同产地虾酱代谢物组的比较

食品科学 2025年第4期46卷 147-153页

作者：刘佳乐郑兰萍刘颖刘敏陈亚泉龙肇付湘晋中南林业科技大学食品科学与工程学院湖南长沙410004 长沙环境保护职业技术学院湖南长沙410004 湖南汇湘轩生物科技股份有限公司湖南省调味料绿色制造工程技术研究中心湖南浏阳410323 湖南湘典食品有限公司湖南浏阳410300

目的:探究不同产地虾酱非挥发性小分子组成。方法:采用超高效液相色谱-静电场轨道阱高分辨质谱技术对山东、广东、河北地区虾酱中的代谢物进行检测;结合正交偏最小二乘判别分析识别不同产地虾酱特征性代谢物。结果:虾酱富含氨基酸、脂... 详细信息

目的:探究不同产地虾酱非挥发性小分子组成。方法:采用超高效液相色谱-静电场轨道阱高分辨质谱技术对山东、广东、河北地区虾酱中的代谢物进行检测;结合正交偏最小二乘判别分析识别不同产地虾酱特征性代谢物。结果:虾酱富含氨基酸、脂肪酸类代谢物,形成了大量N-脂酰化合物,相对含量高的有肉桂酸、11’-羧基-α-铬醇和β-亮氨酸等,虾酱中还新发现多巴胺、去甲肾上腺素、6-羟基褪黑素、γ-谷氨酰胺-5-羟基色氨酸等积极神经递质类活性物质;山东虾酱主要有肉桂酸、β-亮氨酸等特征代谢物;广东虾酱主要有12-Hete-T和N-油酰牛磺酸等特征代谢物;河北虾酱主要有二十碳五烯酸和花青素-3-O-(6’-丙酰基阿拉伯糖苷)等特征代谢物。结论:虾酱富含β-亮氨酸、谷氨酸、脯氨酸-缬氨酸和亮氨酸-甘氨酸等小分子物质和牛磺酸、去甲肾上腺素和多巴胺等生物活性成分。不同产地虾酱中代谢产物组成具有一定的产地特异性。

关键词：虾酱代谢组学超高效液相色谱-静电场轨道阱高分辨质谱正交偏最小二乘判别分析特征代谢物

synthesis of Triphenyltin 2-(1,2-Ethylenedithio) Methylene-3-Oxo-5-Aryl-4-Pentenoate

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Chinese Chemical Letters 1998年第1期9卷 21-22页

作者： Li, JX liu, q Zhao, MX liu, JF Li, sY He, Y NE Normal Univ Dept Chem Changchun 130024 Peoples R China

Under esterification conditions, 2-(1,2-ethylenedithio) methylene-3-oxo-5-aryl-4-pentenoic acid 3 afforded the decarboxylated products 4. The triphenyltin 2-(1, 2-ethylenedithio) methylene-3-oxo-5-aryl-4-pentenoates 5... 详细信息

关键词： esterification alpha-oxo ketene dithioacetal aryl aldehyde

DYNAMIC ANALYsIs OF ARREsT OF BUCKLE PROPAGATION ON A BEAM ON A NONLINEAR ELAsTIC FOUNDATION BY FEM

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Acta Mechanica solida sinica 1997年第1期10卷 28-30,32-35页

作者： Zou, sZ Huang, YY liu, ZH qian, q sHAsHI UNIV SHASHI 434000PEOPLES R CHINA HUAZHONG UNIV sCI & TECHNOL WUHAN 430074PEOPLES R CHINA ACAD sINICA INST MECHBEIJING 100080PEOPLES R CHINA

Based on the dynamic governing equation of propagating buckle on a beam on a nonlinear elastic foundation, this paper deals with an important problem of buckle arrest by combining the FEM with a time integration technique. A new conclusion completely different from that by the quasi-static analysis about the buckle arrestor design is drawn. This shows that the inertia of the beam cannot be ignored in the analysis under consideration, especially when the buckle propagation is suddenly stopped by the arrestors.

关键词： buckle propagation arrest of buckle beam on a nonlinear foundation finite element method

Comparing Ordinary Kriging and Regression Kriging for soil Properties in Contrasting Landscapes

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Pedosphere 2010年第5期20卷 594-606页

作者： q.ZHU H.s.LIN Department of Crop and soil sciences 116 ASI BuildingThe Pennsylvania State UniversityUniversity ParkPA 16802(USA)

The accuracy between ordinary kriging and regression kriging was compared based on the combined consideration of sample size,spatial structure,and auxiliary variables(terrain indices and electromagnetic induction surveys) for a variety of soil properties in two contrasting landscapes(agricultural ***).When spatial structure could not be well captured by point-based observations(e.g.,when the ratio of sample spacing over correlation range was > 0.5),or when a strong relationship existed between target soil properties and auxiliary variables(e.g.,their R2 was > 0.6),regression kriging(RK) was more accurate for interpolating soil properties in both landscapes ***,ordinary kriging(OK) was *** depth and wetness condition did not appear to affect the selection of kriging for soil moisture interpolation,because they did not significantly change the ratio of sample spacing over correlation range and the relationship with the auxiliary *** of a smaller ratio of elevation change over total study area(E/A = 1.2) and multiple parent materials in the agricultural land,OK was generally more accurate in that *** contrast,a larger E/A ratio of 6.8 and a single parent material led to RK being preferable in the steep-sloped forested *** results from this study can be useful for selecting kriging for various soil properties and landscapes.

关键词： geostatistics soil moisture spatial interpolation spatial structure