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Enhancing aerodynamic performances of a high-turning compressor cascade via boundary layer suction

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Science China(Technological Sciences) 2010年第10期53卷 2748-2755页

作者： GUO Shuang1, CHEN ShaoWen1, lU HuaWei2, SONG YanPing1 & CHEN Fu1 1 School of Energy Science and engineering, Harbin institute of technology, Harbin 150001, China 2 Marine engineering college, dalian Maritime University, dalian 116026, China 1. School of Energy Science and engineering Harbin Institute of Technology Harbin 150001 China2. Marine Engineering College Dalian Maritime University Dalian 116026 China

Experimental investigation was carried out to study the effect of suction positions and suction flow rates on the aerodynamic performance of a compressor cascade with a large camber angle. The ink-trace flow visualization was conducted and the flow fields of the cascade were also measured. Three types of boundary layer suction configurations are compared,i.e. the suction surface suction,the endwall suction and the compound suction. Experimental results show that the large amount of suction flow rate gains more losses reduction than the small amount for a certain proper suction configuration,but the speed of loss decline slows down as the suction flow rate goes on increasing. Boundary layer suction on the suction surface obviously enhances the ability of the boundary layer around the midspan to withstand the negative pressure gradient of the flow passage. The range of the suction surface corner is also decreased. If the suction slot locates in the corner separation region where severe separation has happened,the flow separation will be terminated at the slot and redevelop downstream. And boundary layer suction on the endwall mainly influences the endwall corner region in remarkably delaying,lessening and reorganizing the corner separation. While the whole flow field is remarkably improved at both midspan and the corner region in the compound suction schemes. At higher suction flow rates,the aerodynamic performance of the compressor cascade is better than that with boundary layer suction simply on the suction surface or on the endwall. When the suction flow rate is 1.5% of the inlet mass flow,the compound suction scheme achieves a maximum loss reduction of 17% compared with the cascade without boundary layer suction.

关键词： boundary layer suction high-turning diffusion cascade suction flow rate suction position experimental investigation

Riverine sulfate sources and behaviors in arid environment,Northwest China:Constraints from sulfur and oxygen isotopes

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Journal of Environmental Sciences 2024年第3期137卷 716-731页

作者： Yifu Xu Wenjing liu bing Xu Zhifang Xu Key laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

The fate of riverine sulfate ion (SO_(4)^(2-)) and its environmental effects in arid environment are difficult to evaluate due to its complicated sources and strongly coupled behaviors with water cycle which is significantly modified by *** understand the sulfur cycle in aquatic systems in arid environment,the chemical and sulfur and oxygen isotopic compositions (δ^(34)S_(SO4)and δ^(18)O_(SO4)) of major rivers around the Badain Jaran Desert,northwestern China,were *** rivers had averaged SO_(4)^(2-)content at 1336μmol/l,over 10times higher than the global *** δ^(34)S_(SO4)and δ^(18)O_(SO4)values ranged from-5.3‰to+11.8‰and+1.6‰to+12.8‰,*** end-member analysis and the inverse model showed that riverine sulfate was mainly derived from evaporites dissolution (0-87%),sulfide oxidation (13%-100%) and precipitation (0-33%),indicating heterogeneity in sulfur sources and behaviors along the river drainage with the lithology variations and climate *** isotopic tools combining with hydro-chemistry compositions could be applied to reveal sulfur cycle in arid *** on the calculation,sulfide oxidation plays the primary role in the headwater and upstream in the Qilian-Mountains area,where sulfide is widely *** the proportion of evaporites dissolution contributing to riverine sulfate is much higher in downstream in a drier ***,less precipitation and higher temperature can lead to more intensive evaporation,affecting the process of sulfide oxidation and enhancing the rates of evaporites dissolution and sulfate precipitation in the basin.

关键词： Sulfur and oxygen isotopes Source apportionment Inverse model Arid environment Inland rivers Northwestern China

A Mathematical Model for EstimatingElectroosmosis Effect on Water Displacing Oil Process in Porous Media and Its Application

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Journal of Earth Science 1999年第3期18卷 241-244页

作者： Yun Junxian (chemical engineering institute, dalian University of technology, dalian 116012)Zhang Ningsheng Zhang Wei Wu Xinmin(Department of Petroleum engineering, Xi’an Petroleum institute, Xi’an 710065) chemical engineering institute Dalian University of Technology DaLian 116012 Department of Petroleum engineering Xi'an Petroleum Institute Xi'an 710065

A mathematical model based on Darcy's law and electroosmosis equation in porous media is developed and two parameters named electroosmosis coefficient K, and relative electroosmosis coefficient Kre are used to calculate the curves of Ke and Krevs. water saturation whick are employed to estimate the effect of electroosmosis on water displacing oil process in sandstone cores. Under the conditions of constant injection rate displacement and constant electrical potential gradient, the method to calculate parameters K. and K. at different water saturation is developed and unsteadystate displacement *** data under the effect of electroosmosis are used to determine the Parameter values. The results show that K, and K, are increased firstly with increasing water saturation and then decreased. This trend shows the inter-relationship between electroosmosis and the water displacing oil process. Finally, application of the model to ECMP mechauics studies and ac-tual reservoirs is analyzed in this peper.

关键词： electroosmosis mathematical model electrical-chemical producing method displacement experiment porous media

Adsorption and reaction of CO and O_2 on the Ag/Pt(110) surface studied by photoemis-sion electron microscopy

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Chinese Science Bulletin 2001年第12期46卷 998-1002页

作者： HUANG Weixin & BAO XinheState Key laboratory of Catalysis, dalian institute of chemical Physics, Chinese Academy of Sciences, dalian 116023, China State Key laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian China

The Ag/Pt(110) model catalyst was prepared by evaporating silver on Pt(110). Adsorption and reaction of CO and O2 on Ag/Pt(110) surface were studied in situ by photo-emission electron microscopy (PEEM) during the pressure range of 10-5-10-2 Pa at 480 K. The Ag/Pt(110) surface consisted of Pt(110), AgPt interface and Ag area after annealing at 500 K. The dosing pressure of CO and O2 had a larger influence on their adsorption on the Ag area than on the Pt(110) and AgPt interface. Small Pt clusters formed on the Ag area and AgPt interface, which had a stronger ability to adsorb CO than Pt(110) terrace. The existence of Ag had an obvious influence on the kinetic of CO oxidation on Pt(110). No pattern was observed on the AgPt interface under the same condition when the formation of reaction-diffusion waves occurred on Pt(110).

关键词： silver Pt(110) carbon monoxide oxygen adsorption reaction photoemission electron microscopy.

THE　THEORY　OF　RESONANT　AND　NONRESONANT　PUMP－PROBE　POlARIZATIONSPECTROSCOPYFORGROUND－STATECOHERENCE

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Chinese chemical letters 1996年第4期7卷 353-356页

作者： Yi ZHAO Guo Zhong HE(State Key laboratory of Molecular Reaction Dynamics, dalian institute of chemical Physics. Chinese Academy of Sciences, dalian 116023) CHINESE ACAD SCI DALIAN INST CHEM PHYSSTATE KEY LAB MOL REACT DYNAMDALIAN 116023PEOPLES R CHINA

A density matrix treatment of the time evolution of the third order polarization response describing the ground state coherence induced by ultrafast pulses is given. The explicit formulas of polarization response for nonresonant and resonant excitation are derived. The results show that the signal can be greatly enhanced in case of resonance. For specification, we discuss the ground- state rotational coherence based on the if irreducible tensor algebra.

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Catalytic oxidation of soot particulates over MnO_x-CeO_2 oxides prepared by complexation-combustion method

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Journal of Natural Gas Chemistry 2010年第1期19卷 86-90页

作者： Wenjuan Shan, Na Ma, Jiali Yang, Xiaowei Dong, Chang liu, lingling Wei institute of Chemistry for Functionalized Materials, college of Chemistry and chemical engineering, liaoning Normal University, dalian 116029, liaoning, China [a] institute of Chemistry for Functionalized Materials College of Chemistry and Chemical Engineering Liaoning Normal University Dalian 116029 Liaoning China

MnOx-CeO2 oxides prepared by complexation-combustion method were used for soot oxidation. The highest conversion rate of soot was obtained on a MnOx-CeO2 oxide prepared under mild acid condition of pH = 4, where the oxidation temperature corresponding to maximum activity was decreased more than 150 ℃ compared with that of un-catalytic soot oxidation. The structure and property of the catalysts were investigated by X-ray powder diffraction （XRD） and temperature programmed reduction （TPR）. The results indicated that there were at least two kinds of Mn species present in MnOx-CeO2 catalysts, i.e. Mn ions within CeO2 lattice and high dispersion MnOx on the surface of CeO2. The presence of Mn ions in the CeO2 lattice improved the oxygen vacancy due to the charge difference, and the CeO2 considerably decreased the reduction temperature of MnOx. The capability to activate oxygen through the oxygen exchange between O2 in gas phase and lattice oxygen species in MnOx-CeO2 oxide contributed to the high catalytic activity for the reaction.

关键词： soot oxidation MnOx-CeO2 oxides active oxygen

Sensing Time Optimization in Energy-Harvesting Cognitive Radio with Interference Rate Control

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China Communications 2016年第1期13卷 47-56页

作者： DENG Zhian lIU Xin JIA Min lU Weidang School of Information Science and technology Dalian Maritime University School of Information and Communication engineering Dalian University of Technology Communication Research Centre Harbin Institute of Technology college of Information engineering Zhejiang University of Technology

In this paper,an energy-harvesting cognitive radio(CR) is considered,which allows the transmitter of the secondary user(SU) to harvest the primary signal energy from the transmitter of the primary user(PU) when the presence of the PU is *** the harvested energy is converted into the electrical power to supply the transmission of the SU at the detected absence of the *** adopting the periodic spectrum sensing,the average total transmission rate of the SU is maximized through optimizing the sensing time,subject to the constraints of the probabilities of false alarm and detection,the harvested energy and the interference rate *** simulation results show that there deed exists an optimal sensing time that maximizes the transmission rate,and the maximum transmission rate of the energy-harvesting CR can better approach to that of the traditional CR with the increasing of the detection probability.

关键词： cognitive radio spectrum sensing energy detection energy harvest transmission rate

A New Quaternary Ammonium Heteropolyoxotungstate Catalyst for Propylene Epoxidation to Propylene Oxide

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Chinese chemical letters 2004年第12期15卷 1491-1493页

作者： Ying lU Meng lI Rong Hua ZHANG Zu Wei XI Shuang GAOf dalian institute of chemical Physics, Chinese Academy of Sciences, dalian 116023 dalian institute of chemical Physics Chinese Academy of Sciences

A new quatemary ammonium heteropolyoxotungstant (cat.C) is prepared andcharacterized. And the cat.C also is an reaction-controlled phase-transfer catalyst The catalyticsystem of O_2/EAHQ (2-ethylanthrahydroquinone)/cat.c is used for the epoxidation of propylene.Under the optimal conditions, the yield of propylene oxide based on EAHQ is 84.1%, theselectivity for propylene oxide based on propylene is 99.8% and the conversion of propylene basedon EAHQ is 84.3%. The cat.c precipitates after the epoxidation reaction for easy separation.The cat C is stable enough to be recycled three times without any loss in selectivity.

关键词： Epoxidation propylene reaction-controlled phase-transfer catalyst.

Preparation of a Novel Micro/nano Tubes via Electrospun Fiber as a Template

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Journal of Materials Science & technology 2004年第5期20卷 613-616页

作者： Taiqi lIUSchool of Materials and chemical engineering, Beijing institute of Petro-chemical technology, Beijing 102617, China Sch. of Mat. and Chem. Eng. Beijing Inst. of Petrochem. Technol. Beijing 102617 China

Poly (para-xylylene) hollow fibers with inner diameters can be prepared via template fibers electrospun from solutions. The PPX is deposited from the vapor phase and the template fiber is selectively removed by heat treatment or solvent extraction. The PPX is partially crystalline and the crystal modification depending on the route is used to extract the template fiber. The thermal stability of the hollow fibers is only slightly reduced relative to the bulk material and the same holds for the UV-stability.

关键词： Electrospinning Fiber chemical vapor deposition Physical vapor deposition Crystal Conductivity