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Performance investigation of plasma magnetohydrodynamic power generator

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Applied Mathematics and Mechanics(English Edition) 2018年第3期39卷 423-436页

作者： Hulin HUANG linyong li Guiping ZHU Lai li College of Astronautics Nanjing University of Aeronautics and Astronautics

A magnetohydrodynamic （MHD） power generator system involves several subjects such as magnetohydrodynamics, plasma physics, material science, and structure mechanics. Therefore, the performance of the MHD power generator is affected by many factors, among which the load coefficient k is of great importance. This paper reveals the effect of some system parameters on the performance by three-dimensional （3D） numerical simulation for a Faraday type MHD power generator using He/Xe as working plasma. The results show that average electrical conductivity increases first and then decreases with the addition of magnetic field intensity. Electrical conductivity reaches the maximum value of 11.05 S/m, while the applied magnetic field strength is B = 1.75 T. When B 〉 3 T, the ionization rate along the midline well keeps stable, which indicates that the ionization rate and three-body recombination rate （three kinds of particles combining to two kinds of particles） are approximately equal, and the relatively stable plasma structure of the mainstream is preserved. Efficiency of power generation of the Faraday type channel increases with an increment of the load factor. However, enthalpy extraction first increases to a certain value, and then decreases with the load factor. The enthalpy extraction rate reaches the maximum when the load coefficient k equals 0.625, which is the best performance of the power generator channel with the maximum electricity production.

关键词： magnetohydrodynamic (MHD) power generator, Faraday type generatorchannel, ionization load factor, magnetic field

A hydrodynamic model of loop seal with a fluidized standpipe for a circulating fluidized bed

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Particuology 2018年第1期16卷 50-58页

作者： Changjin li Zheng ZOU Hongzhong li Qingshan Zhu State Key Laboratory of Multi-phase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

Loop seals are among the most common non-mechanical valves used in circulating fluidized bed sys- tems. In the present work. a fundamental study is conducted of a fluidized loop seal, which consists of a fluidized standpipe, a fluidized supply chamber, and a fluidized recycling chamber. Based on the princi- ples of momentum, mass. and energy conservation, a hydrodynamic model for a loop seal is established, consisting of 13 equations. The effects of operating conditions such as the bottom aeration rate, total solid inventory, and fluidizing gas velocity in the riser on the solids flow rate and the performance of the loop seal are studied by a combination of model analysis and experiments. The experiments are carried out in a circulating fluidized bed with silica gel particles （Geldart group A）. The model predictions show good agreement with the experimental data.

关键词： Circulating fluidized bed Loop seal Hydrodynamic model

Acidogenic sludge fermentation to recover soluble organics as the carbon source for denitrification in wastewater treatment： Comparison of sludge types

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Frontiers of Environmental Science & Engineering 2018年第4期12卷 25-32页

作者： lin lin Ying-yu li Xiao-yan li Environmental Engineering Research Centre Departmelt of Civil Engineering The University of Hong Kong Pokfulam Hong Kong China Shenzhen Engineering Research Laboratory for Sludge and Food Waste Treatment and Resource Recovery Graduate School at Shenzhcn Tsinghua University Shcnzhen 518055 China＊

For biological nitrogen （N） removal from wastewater, a sufficient organic carbon source is requested fbr denitrification. However. the organic carbon/nitrogen ratio in municipal wastcwatcr is becoming lower in recent years, which increases the demand for the addition of external organic carbon, e.g. methanol, in wastewater treatment. The volatile fatty acids （VFAs） produced by acidogenic fenncntation of sewage sludge can be an attractive alternative for methanol. Chemically enhanced primary sedimentation （CEPS} is an effective process that applies chemical coagulants to enhance the removal of organic pollutants and phosphorus from wastewater by sedimentation. In temls of the chemical and biological characteristics, the CEPS sludge is considerably different from the conventional primary and secondary sludge. In the present study, FeCI3 and PACI （polyalunfinum chloride） were used as the coagulants for CEPS treatment of raw sewage. The derived CEPS sludge （Fe-sludge and Al-sludge） was then processed with mcsophilic acidogenic fennentation to hydrolysc the solid organics and produce VFAs for organic carbon recovery, and the sludge acidogenesis efficiency was compared with that of the conventional primary sludge and secondary sludge. The results showed that the Fe-sludge exhibited the highest hydrolysis and acidogenesis efficiency, while the Al-sludge and secondary＇ sludge had lower hydrolysis efficiency than that of primary sludge. Utilizing ffie Fc-sludgc fermentation liquid as tbc carbon source for denitrificatiom more than 99%of nitrate removal was achieved in the main-stream wastewater treatment without any external carbon addition, instead of 35% obtained from the conventional process of primary sedimentation followed by the oxic/anoxic （O/A） treatment.

关键词： Sewage sludge Chemically enhanced primary sedimentation(CEPS) Acidogenic fermentation Organic carbon recovery Nitrogen removal

Metallic iron nanoparticles:Flame synthesis,characterization and magnetic properties

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Particuology 2013年第4期11卷 460-467页

作者： Yunfeng li Yanjie Hu Guangjian Huang Chunzhong li Key Laboratory for Ultrafine Materials of Ministry of Education School of Materials Science and EngineeringEast China University of Science & Technology Department of Surgery Huashan HospitalFudan University

Metallic iron （Fe） nanoparticles （NPs） with a typical core-sheU structure have been prepared by a simple and continuous flame spray pyrolysis （FSP） method, which are stabilized by the corresponding Fe304 shell with a thickness of 4-6 nm. The size of metallic Fe cores is about 30-80 nm. The core-shell structured iron NPs show an air stability as long as one month as a result of the protection of oxide shell. Through the control of the residence time of materials in flame and flame atmosphere, metallic Fe and iron oxides are obtained, showing a better external magnetic field responsibility. It is concluded that the evolution of morphology and composition of flame-made magnetic NPs could be attributed to the competition mechanism between reduction and oxidation reactions of in situ flame combustion, which offers more choices and better effective design strategy for the synthesis of advanced functional materials via FSP techniques.

关键词： Iron NPsFSPReducing flameMagnetic properties

A mini review on strategies for heterogenization of rhodium-based hydroformylation catalysts

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Frontiers of Chemical Science and Engineering 2018年第1期12卷 113-123页

作者： Cunyao li Wenlong Wang li Yan Yunjie Ding Dalian National Laboratory for Clean Energy 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 116023 China

Hydroformylation has been widely used in industry to manufacture high value-added aldehydes and alcohols, and is considered as the largest homogenously catalyzed process in industry. However, this process often suffers from complicated operation and the difficulty in catalyst recycling. It is highly desirable to develop a heterogeneous catalyst that enables the catalyst recovery without sacrificing the activity and selectivity. There are two strategies to afford such a catalyst for the hydrofromylation： immobilized catalysts on solid support and porous organic ligand （POL）-supported catalysts. In the latter, high concentration of phosphine ligands in the catalyst framework is favorable for the high dispersion of rhodium species and the formation of Rh-P multiple bonds, which endow the catalysts with high activity and stability respectively. Besides, the high linear regioselectivity could be achieved through the copolymerization of vinyl functionalized bidentate ligand （vinyl biphephos） and monodentate ligand （3vPPh3） into the catalyst framework. The newly-emerging POL-supported catalysts have great perspectives in the industrial hydroformylation.

关键词： hydroformylation porous organic ligand (POL)-supported catalysts heterogeneous catalysis high stability immobilization catalysts

Investigation of Endwall Flow Behavior with Plasma Flow Control on a Highly Loaded Compressor Cascade

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Journal of Thermal Science 2012年第4期21卷 295-301页

作者： Xiaohu ZHAO Yinghong li Yun WU Jun li Science and Technology on Plasma Dynamics Laboratory Air Force Engineering University Xi' an 710038 China

To discover the flow behavior in the endwall region and mechanism of plasma flow control on a highly loaded compressor cascade, distributions of static pressure coefficient, total pressure loss coefficient and streamline pat- tern were investigated. Results show that cross flow from the pressure surface to neighboring suction surface ex- ists under pitch-wise pressure gradient. The deflected endwall boundary layer flow interacts with the incoming flow, and then both of them leave off the endwall in tile form of a span-wise vortex. Effect of angle of attack on static pressure is greater than that of free stream velocity. The distinct variations of total pressure loss with end- wall actuations are mainly located within the outer verge of a triangular area with high total pressure loss. Effect of pitch-vAse actuation on separated flows is much better than that of stream-wise actuation, and both enhance with the increase of angle of attack and actuation strength. An efficient method for plasma flow control in the endwall region is the increase of actuation strength, such as adjusting discharge voltage or changing plasma power supply.

关键词： plasma flow control compressor cascade endwall region vortex

Effect of rock composition microstructure and pore characteristics on its rock mechanics properties

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International Journal of Mining Science and Technology 2018年第2期28卷 303-308页

作者： li Huamin li Huigui Wang Kailin liu Chuang School of Energy Science and Engineering Henan Polytechnic University Opening Project of Key Laboratory of Deep Mine Construction Henan Polytechnic University

This paper is to study the influence of composition, microstructure and pore characteristics on the rock mechanical properties. Five kinds of sandstone compositions were analyzed by using X-ray diffraction instrument. And the microstructure was observed by using scanning electron microscope. Then the pore distribution characteristic was investigated by using the low field nuclear magnetic resonance equipment. Finally, the uniaxial compression test was carried out to investigate the mechanical characteristics by using RMT150C mechanics experimental system and the uniaxial compressive strength, Poisson's ratio and elastic modulus were obtained. Compared to the analysis of the composition, structure and pore distribution and mechanical properties of the five kinds of sandstones, the relationship among composition,structure, pore distribution and mechanical properties was obtained. The results show that the composition, microstructure, pore distribution and mechanical properties of sandstone are closely *** the decrease of feldspar and quartz particles, the compressive strength and elastic modulus increase, while the porosity decreases.

关键词： Mechanical characteristics Pore characteristics Microstructure Composition Scanning electron microscope

Preparation of LaFe_(0.95)Pd_(0.05)O_3 perovskites and their catalytic performances in methane combustion

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Journal of Natural Gas Chemistry 2012年第2期21卷 113-118页

作者： Xiaojing Zhang Yong li Huaju li Wenjie Shen State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

The physic-chemical properties of LaFe0.95Pd0.05O3 perovskites were strongly dependent on the temperature of calcination. Most of the organic substances and inorganic impurities were readily removed at 723 K but single-phase and well crystallized perovskite structure was formed at 873 K. With further raising the calcination temperature, the crystallite size of LaFe0.95Pd0.05O3 increased considerably. The LaFe0.95Pd0.05O3 sample that calcined at 1073 K showed only comparable activity as the reference LaFeO3 catalyst, in particular below 923 K, but pre-treatment with the reaction gas at 1223 K resulted in significantly enhanced activity due to the generation of active PdO species on the surface. The hysteresis feature upon heating-cooling cycle further confirmed the strong interaction between Pd and LaFeO3 in the perovskite structure.

关键词： perovskite LaFe0.95Pd0.05O3 calcination temperature pre-treatment methane combustion

Chemical vapor deposition growth of two-dimensional heterojunctions

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Science China(Physics,Mechanics & Astronomy) 2018年第1期61卷 2-18页

作者： Yu Cui Bo li JingBo li ZhongMing Wei State Key LaboratoO' of Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences & College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences Beij'ing 100083 China

The properties of two-dimensional(2 D) layered materials with atom-smooth surface and special interlayer van der Waals coupling are different from those of traditional materials. Due to the absence of dangling bonds from the clean surface of 2 D layered materials, the lattice mismatch influences slightly on the growth of 2 D heterojunctions, thus providing a flexible design strategy.2 D heterojunctions have attracted extensive attention because of their excellent performance in optoelectronics, spintronics, and valleytronics. The transfer method was utilized for the fabrication of 2 D heterojunctions during the early stage of fundamental research on these materials. This method, however, has limited practical applications. Therefore, chemical vapor deposition(CVD) method was recently developed and applied for the preparation of 2 D heterojunctions. The CVD method is a naturally down-top growth strategy that yields 2 D heterojunctions with sharp interfaces. Moreover, this method effectively reduces the introduction of contaminants to the fabricated heterojunctions. Nevertheless, the CVD-growth method is sensitive to variations in growth conditions. In this review article, we attempt to provide a comprehensive overview of the influence of growth conditions on the fabrication of 2 D heterojunctions through the direct CVD method. We believe that elucidating the effects of growth conditions on the CVD method is necessary to help control and improve the efficiency of the large-scale fabrication of 2 D heterojunctions for future applications in integrated circuits.

关键词： two-dimensional materials heterojunctions chemical vapor deposition