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Journal of Thermal Science 2020年第4期29卷 945-954页

作者： WANG yi LI Qingkuo BAI Huan ZHOU Xueqi LU Xin’gen School of Aeronautics and Astronautics Central South UniversityChangsha 410083China AECC Hunan Aviation Powerplant Research Institute Hunan Key Laboratory of Turbomachinery on Small and Medium Areo-EngineZhuzhou 412002China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China

As the total pressure ratio of centrifugal compressors increases, the diffuser inlet flow becomes highly subsonic or even supersonic, which causes additional shock loss. The shock loss leads the stage performance to drop greatly. Pre-compression is an efficient method for reducing shock loss and improving the stage performance. To study the effect of wedge diffusers with pre-compression blades on centrifugal compressor performance, wedge diffusers with various pre-compression angles, divergence angles and numbers of blades were designed and investigated via a numerical method. As a result, it is found that the compressor stage achieves high peak efficiency when the pre-compression angle ranges from 2.5° to 5.5° and when the divergence angle ranges from 7° to 9°. As the number of blades increases, the total pressure ratio and adiabatic efficiency of the compressor stage increase slightly, whereas the surge margin of the stage decreases.

关键词： wedge diffuser pre-compression high Subsonic centrifugal compressor

Exploring the influence of environmental factors in partitioning evapotranspiration along an elevation gradient on Mount Gongga, eastern edge of the Qinghai-Tibet Platea, China

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Journal of Mountain Science 2020年第2期17卷 384-396页

作者： sun Ju-ying sun Xiang-yang HU Zhao-yong WANG gen-xu Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China

Evapotranspiration(ET) is a crucial part of the global hydrological cycle, and quantifying ET components is significant for understanding the global water cycle and energy balance. However, there is no consensus on the value of ET components, especially in topographic abrupt change zone, such as eastern margin of the Qinghai-Tibet Platea, where values of ET changes along the altitudinal gradients. Our aim is to explore the influencing factors in partitioning evapotranspiration and how ET components change with increasing elevations. A novel approach was proposed to estimate ET components by adding net solar radiation(Rn) instead of the vapor pressure deficit(VPD) into the underlying water use efficiency(u WUE) model based on one-year continuous measurements of flux data along the elevation gradient on Mount Gongga. Correlation analysis shows that the u WUE model's performance can be improved significantly by considering Rn instead of VPD, with correlation coefficients increasing by 35%-64%. The ratios of transpiration(T) to ET(T/ET) were 0.47, 0.48, 0.50 and 0.35 for the deciduous broadleaf forest(BF), mixed coniferous and deciduous broadleaf forest(MF), evergreen needle forest(ENF) and shrub land(SL), respectively. Leaf area index(LAI) and air temperature(Ta) were the two main controlling factors in determining T/ET during the growing season and at an annual scale, while Rn and Ta played more important roles during the dormant season. This study highlights the importance of incorporating Rn in partitioning evapotranspiration by using the water use efficiency(WUE) method in a humid mountainous region, which can improve the estimation of T/ET on a global scale.

关键词： Eddy covariance Water use efficiency Radiation Evapotranspiration components

An Empirical Likelihood Method in a Partially Linear Single-index Model with Right Censored Data

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Acta Mathematica Sinica,English Series 2012年第5期28卷 1041-1060页

作者： yi Ping YANG Liu gen XUE Wei Hu CHENG College of Mathematics and Statistics Chongqing Technology and Business University College of Applied Sciences Beijing University of Technology

Empirical-likelihood-based inference for the parameters in a partially linear single-index model with randomly censored data is investigated. We introduce an estimated empirical likelihood for the parameters using a synthetic data approach and show that its limiting distribution is a mixture of central chi-squared distribution. To attack this difficulty we propose an adjusted empirical likelihood to achieve the standard X2-1imit. Furthermore, since the index is of norm 1, we use this constraint to reduce the dimension of parameters, which increases the accuracy of the confidence regions. A simulation study is carried out to compare its finite-sample properties with the existing method. An application to a real data set is illustrated.

关键词： Censored data regression model empirical likelihood x2-distribution

Improved Twin Support Vector Machine Algorithm and Applications in Classification Problems

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China Communications 2024年第5期21卷 261-279页

作者： sun yi Wang Zhouyang Beijing University of Posts and Telecommunications School of Computer Science(National Pilot Software Engineering School) Beijing University of Posts and Telecommunications International School

The distribution of data has a significant impact on the results of *** the distribution of one class is insignificant compared to the distribution of another class,data imbalance *** will result in rising outlier values and ***,the speed and performance of classification could be greatly *** the above problems,this paper starts with the motivation and mathematical representing of classification,puts forward a new classification method based on the relationship between different classification *** with the vector characteristics of the actual problem and the choice of matrix characteristics,we firstly analyze the orderly regression to introduce slack variables to solve the constraint problem of the lone *** we introduce the fuzzy factors to solve the problem of the gap between the isolated points on the basis of the support vector *** introduce the cost control to solve the problem of sample ***,based on the bi-boundary support vector machine,a twostep weight setting twin classifier is *** can help to identify multitasks with feature-selected patterns without the need for additional optimizers,which solves the problem of large-scale classification that can’t deal effectively with the very low category distribution gap.

关键词： fuzzy ordered regression(OR) relaxing variables twin support vector machine

An alkaline fusion mechanism for aluminate rare earth phosphor:cation-oxoanion synergies theory

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Rare Metals 2019年第4期38卷 299-305页

作者： yi-Fan Liu Shen-gen Zhang Bo Liu Han-Lin Shen Institute for Advanced Materials and Technology University of Science and Technology Beijing

Waste aluminate rare earth phosphor is an important rare earth elements (REEs) secondary resource, which mainly consists of BaMgAl1()O|7:Eu2+(BAM) and CeMgAl11O19:Tb^3+(CMAT). Alkaline fusion process is widely used to recycle REEs from aluminate phosphor, but the related theory remains imperfect. In this paper, a series of alkaline fusion experiments of CMAT were performed to describe the phase change law of CMAT reactions. Based on comprehensive analysis, cation-oxoanion synergies theory (COST) was proposed to explain the aluminate phosphor structure damage. On the mirror plane of aluminate phosphor crystal structure, alkali metal cations (Na^+,K^+) would substitute rare earth ions, while free oxoanion (OH^-, CO3^2-, O2^2-) can combine with rare earth ions. These two ionic forces ensure that rare earth ions can be substituted by cations. Then, the structure is decomposed. Morphological analysis shows that observable expression of COST can be described by shrinking core model after simplification. Reaction rate constant calculated indicates that the reaction degree is nanometers per second. COST provides a more complete mechanism, and it can help improve rare earth recycling technology furtherly.

关键词： Aluminate phosphor Alkaline fusion Rare earth Mechanism

Optimization on class of operator equations in the probabilistic case setting

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Science China Mathematics 2007年第1期50卷 100-104页

作者： gen-sun FANG Li-xin QIAN School of Mathematical Sciences Beijing Normal UniversityBeijing 100875China College of Mathematics and Physics Zhejiang Normal UniversityJinhua 321004China

In this paper, we introduce a problem of the optimization of approximate solutions of operator equations in the probabilistic case setting, and prove a general result which connects the relation between the optimal approximation order of operator equations with the asymptotic order of the probabilistic width. Moreover, using this result, we determine the exact orders on the optimal approximate solutions of multivariate Freldholm integral equations of the second kind with the kernels belonging to the multivariate Sobolev class with the mixed derivative in the probabilistic case setting.

关键词： probabilistic width Gauss measure multivariate Sobolev space operator equation 41A46 41A63 45L05 60G15

Non-Linear Approximation of Functions with Mixed Smoothness by Sets of Finite Pseudo-Dimension

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Acta Mathematica Sinica,English Series 2007年第4期23卷 671-676页

作者： Guang Gui CHEN gen sun FANG Yuan Long RUAN School of Mathematics and Computer Engineering Xihua University Chengdu 611930 P. R. China School of Mathematical Science Beijing Normal University Beijing 100875 P. R. China

In this paper, the non-linear approximation on the class of multivariate functions with bounded mixed derivatives is investigated, and the asymptotic degree of the non-linear width on this class is determined.

关键词： pseudo-dimension non-linear width mixed smoothness

Thermodynamics and kinetics of extracting zinc from zinc oxide ore by the ammonium sulfate roasting method

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International Journal of Minerals,Metallurgy and Materials 2015年第5期22卷 467-475页

作者： yi sun Xiao-yi Shen Yu-chun Zhai School of Materials and Metallurgy Northeastern University

Thermodynamic analyses and kinetic studies were performed on zinc oxide ore treatment by （NH4）2SO4 roasting technology. The results show that it is theoretically feasible to realize a roasting reaction between the zinc oxide ore and （NH4）2SO4 in a temperature range of 573-723 K. The effects of reaction temperature and particle size on the extraction rate of zinc were also examined. It is found that a surface chemical reaction is the rate-controlling step in roasting kinetics. The calculated activation energy of this process is about 45.57 kJ/mol, and the kinetic model can be expressed as follows： 1 - （1 - α）1/3 = 30.85 exp（-45.57/RT）·t. An extraction ratio of zinc as high as 92% could be achieved under the optimum conditions.

关键词： zinc metallurgy extraction ammonium sulfate ore roasting thermodynamics kinetics

Dark Energy Accretion onto a Black Hole in an Expanding Universe

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Communications in Theoretical Physics 2009年第9期52卷 441-444页

作者： sun Cheng-yi Institute of Modern Physics Northwest University Xi＇an 710069 China

By using the solution describing a black hole embedded in the FLRW universe,we obtain the evolvingequation of the black hole mass expressed in terms of the cosmological *** evolving equation indicates thatin the phant... 详细信息

关键词： black hole dark energy accretion FRW universe

Induction of Protection against Paraquat-induced Oxidative Damage by Abscisic Acid in Maize Leaves is Mediated through Mitogen-activated Protein Kinase

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Journal of Integrative Plant Biology 2009年第10期51卷 961-972页

作者： Hai-Dong Ding Xiao-Hua Zhang Shu-Cheng XU Li-Li sun Ming-yi Jiang A-ying Zhang yin-gen Jin College of Life Sciences Nanjing Agricultural University Nanjing 210095 China College of Biosciences and Biotechnology Yangzhou University Yangzhou 225009 China College of Life Sciences Fuyang Teachers College Fuyang 236032 China National Key Laboratory of Crop genetics and Germplasm Enhancement Nanjing Agricultural University Nanjing 210095 China

Mitogen-activated protein kinase （MAPK） cascade has been shown to be important components in stress signal transduction pathway. In the present study, protection of maize seedlings （Zea mays L.） against paraquat-generated oxidative toxicity by abscisic acid （ABA）, its association with MAPK and ZmMPK5, a candidate for MAPK were investigated. Treatment of maize leaves with exogenous ABA led to significant decreases in the content of malondialdehyde, the percentage of ion leakage and the level of protein oxidation （in terms of carbonyl groups） under paraquat （PQ） stress. However, such decreases were blocked by the pretreatment with two MAPK kinase inhibitors PD98059 and U0126. The damage caused by PQ was further aggravated by inhibitors. Two inhibitors also suppressed the total activities of the antioxidant enzymes superoxide dismutase （SOD, EC 1.***.1.1）, catalase （CAT, EC 1.***.1.6）, ascorbate peroxidase （APX, EC ***）, and glutathione reductase （GR, EC 1.***.4.2）. Besides, treatment with PQ stimulated the activation of a 46 kDa MAPK, which was identified as ZmMPK5 by in-gel kinase assay with immunoprecipitation. These results reveal that ABA-induced protection against PQ-generated oxidative damage is mediated through MAPK cascade in maize leaves, in which ZmMPK5, a candidate for MAPK, is demonstrated to be involved.

关键词： abscisic acid mitogen-activated protein kinase oxidative damage paraquat Zea mays