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Experimental Investigation on Starting Process of Supersonic Single-stage Air Ejector

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Journal of Thermal Science 2012年第4期21卷 348-353页

作者： Zou jian-jun Zhou Jin Lu Hui-qiang Hu yong College of Aerospace and Material Engineering National University of Defense Technology Changsha 410073 China

This paper deals with experimental study of flow field of starting process in two-dimensional, single-stage supersonic ejector on different air total pressure. Schlieren pictures of flow field were taken, static pressure distribu-tions on side wall were measured. The obtained results show that, on critical pressure, the starting main shock waves in ejector oscillated back and forth between the second throat and the middle section of the mixing chamber, it causes the pressure in the second half of the mixing chamber acutely fluctuated .When the working pressure of the active flow is higher than the critical starting pressure, ejector starts normally and the inner flow-field of the mixing chamber keeps stable and the shock waves in the second throat have a certain degree of oscillation . After ejector starts, the operating pressure of the active flow may be lower than the starting pressure .

关键词： supersonic ejector start process flow-field shock waves

Molecular insight into the GaP(110)-water interface using machine learning accelerated molecular dynamics

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Journal of Energy Chemistry 2023年第7期82卷 239-247,I0006页

作者： Xue-Ting Fan Xiao-jian Wen yong-Bin Zhuang jun Cheng State Key Laboratory of Physical Chemistry of Solid Surfaces iChEMCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005FujianChina Shenzhen Research Institute of Xiamen University Shenzhen 518057GuangdongChina Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen 361005FujianChina

GaP has been shown to be a promising photoelectrocatalyst for selective CO_(2)reduction to *** to the relevance of the interface structure to important processes such as electron/proton transfer,a detailed understanding of the GaP(110)-water interfacial structure is of great *** initio molecular dynamics(AIMD)can be used for obtaining the microscopic information of the interfacial ***,the GaP(110)-water interface cannot converge to an equilibrated structure at the time scale of the AIMD *** this work,we perform the machine learning accelerated molecular dynamics(MLMD)to overcome the difficulty of insufficient sampling by *** the help of MLMD,we unravel the microscopic information of the structure of the GaP(110)-water interface,and obtain a deeper understanding of the mechanisms of proton transfer at the GaP(110)-water interface,which will pave the way for gaining valuable insights into photoelectrocatalytic mechanisms and improving the performance of photoelectrochemical cells.

关键词： Photoelectrocatalysis GaP(110)-water interface Machine learning accelerated molecular dynamics

Composition Preference of Amino Acids in Model-Proteins

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Chinese Physics Letters 2001年第3期18卷 449-451页

作者： WANG jian-yong WANG jun WANG Wei National Laboratory of Solid State Microstructure and Department of Physics Nanjing UniversityNanjing 210093

The folding behaviour of some sequences of 36 monomers with different proportion of hydrophobic residues in a three-dimensional lattice based on the Miyazawa-Jernigen interaction *** is found that the sequences with good folding properties are those with an optimal number of hydrophobic residues,neither too many nor too *** reason for the deterioration of folding properties of sequences out of this range has also been analysed.

关键词： matrix. residues sequences

Regional differences in global glacier retreat from 1980 to 2015

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Advances in Climate Change Research 2019年第4期10卷 203-213页

作者： LI Yao-jun DING yong-jian SHANGGUAN Dong-Hui WANG Rong-jun State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou730000China Key Laboratory of Ecohydrology of Inland River Basin Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou730000China University of Chinese Academy of Sciences Beijing100049China

Global warming triggers shrinking and thinning of glaciers worldwide,with potentially severe implications for human ***,regional differences in glacier retreat and its relationship with climatic characteristics have not been conclusively *** this study,regional changes in global glaciers based on two primary features,area change and mass balance,were investigated on the basis of data collected from published research on glacier *** show that during the period 1980—2015,the rate of global glacier area shrinkage was 0.18%per year and that of global glacier mass loss was 0.25 m *** *** of glaciers located at low and middle latitudes was characterized by severe area shrinkage and mass ***,in the Arctic,deglaciation was characterized by ice thinning due to a low area reduction but relatively high mass loss ***,glaciers in high southern latitudes were in a relatively stable *** Mountain Asia exhibited the lowest rate of area shrinkage and mass loss among glaciers located at low and middle latitudes,and a slower rate of mass loss compared with the global *** in the Tropical Andes exhibited the fastest rate of glacier area shrinkage(—1.6%per year),whereas Antarctic and Subantarctic glaciers showed the lowest rate(—0.11%per year).For mass balance,the most negative occurred at Southern Andes(—0.81 m *** year),followed by Alaska(-0.74 m *** year).Only the Antarctic and Subantarctic experienced small mass gain(0.04 m *** year).High levels of correlation are found between the rates of glacier retreat and annual average temperature and annual total precipitation instead of their *** variability of the surface climate conditions in the glacier environment plays a key role in driving these regional differences in global glacier retreat.

关键词： Glacier retreat Regional differences Climate change

Degradation of Acenaphthene by Ozone

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Biomedical and Environmental Sciences 2007年第4期20卷 291-294页

作者： DI WU yong-jun XU jian-LONG WANG Laboratory of Environmental Technology INET Tsinghua University Beijing 100084 China Harbin Institute of Technology Harbin 150001 Heilongjiang China

To investigate the oxidation of acenaphthene （Ace）, a polycyclic aromatic hydrocarbon （PAH） with a saturated C-C bond by ozone and to characterize the intermediate products of ozonation. Methods Ozone was generated from filtered dry oxygen by an ozone generator and continually bubbled into a reactor containing lg/L Ace dissolved in an acetonitrile/water solvent mixture （90/10, v/v） at a rate of 0.5 mg/s. HPLC was used to analyze the Ace concentration. Total organic carbon （TOC） was used to measure the amount of water soluble organic compounds. GC-MS was used to identify the ozonized products. Oxygen uptake rate （OUR） of activated sludge was used to characterize the biodegradability of ozonized products. Results During the ozonation process, Ace was degraded, new organic compounds were produced and these intermediate products were difficult mineralize by ozone, with increasing TOC of soluble organics. The ozonized products were degraded by activated sludge more easily than Ace. Conclusion Ozonation decomposes the Ace and improves its biodegradability. The ozonation combined with biological treatment is probably an efficient and economical way to mineralize acenaphthene in wastewater.

关键词： Ozone Acenaphthene PAHs Biodegradation Persistent organic pollutant

The catassembled generation of naphthalene diimide coordination networks with lone pair-π interactions

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Science China Chemistry 2016年第11期59卷 1492-1497页

作者： yong Chen jian-jun Liu Chang-Rong Fan jun-Qian Li Mei-Jin Lin College of Chemistry Fuzhou University State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of Sciences

Catassembly is a new concept in molecular assembly that is analogous to catalysis in chemical synthesis. However, for most molecular-assembled processes, the catassembler contributions are rather inconspicuous due to the low activation barriers. As a result, few systems dealing with the catassembly are available until now. In this paper, we report that naphthalene diimide coordination networks are formed under the catassembly of lone-pair-bearing catassemblers(e.g., N,N-dimethylacetamide, N-methylpyrrolidin-2-one). During such molecular assembly, a stable transition state between the electron-deficient naphthalene diimide tectons and catassemblers via the less common lone pair-π interactions was observed, which is supposed to play the key role in the enhancement of coordination abilities of organic tectons and thus formation of the final coordination networks.

关键词： catassembly coordination network naphthalene diimide lone pair-π interaction

First-principle study on the surface atomic relaxation properties of sphalerite

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International Journal of Minerals,Metallurgy and Materials 2012年第9期19卷 775-781页

作者： jian Liu Shu-ming Wen yong-jun Xian Shao-jun Bai Xiu-min Chen Faculty of Land Resource Engineering Kunming University of Science and Technology Kunming 650093 China National Engineering Laboratory of Vacuum Metallurgy Kunming University of Science and Technology Kunming 650093 China

The surface properties of sphalerite （ZnS） were theoretically investigated using first principle calculations based on the density functional theory （DFT）. DFT results indicate that both the （110） and the （220） surfaces of sphalerite undergo surface atom relaxation after geometry optimization, which results in a considerable distortion of the surface region. In the normal direction, i.e., perpendicular to the sur- face, S atoms in the first surface layer move outward from the bulk （dl）, whereas Zn atoms move toward the bulk （d2）, forming an S-enriched surface. The values of these displacements are 0.003 nm for dl and 0.021 nm for d2 on the （110） surface, and 0.002 nm for dl and 0.011 nm for d2 on the （220） surface. Such a relaxation process is visually interpreted through the qualitative analysis of molecular mechanics. X-ray photoelectron spectroscopic （XPS） analysis provides the evidence for the S-enriched surface. A polysulphide （S n^2- ） surface layer with a bind- ing energy of 163.21 eV is formed on the surface of sphalerite after its grinding under ambient atmosphere. This S-enriched surface and the S 2- surface layer have important influence on the flotation properties ofsphalerite. Keywords：

关键词： sphalerite surface relaxation density fimctional theory froth flotation

Adsorption and Reaction of CN +O→OCN on Cu(100) Surface: A Density Functional Theory Study

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Chinese Journal of Structural Chemistry 2005年第8期24卷 865-874页

作者： LI Yi HU jian-Ming ZHANG yong-Fan LI jun-Qiana Department of Chemistry Fuzhou University ChinaFuzhou 350002 Scientific and Technical Section Command Academy of FuzhouThe Chinese People''s Armed Police Force ChinaFuzhou 350002 State Key Laboratory of Structural Chemistry ChinaFuzhou 350002

The adsorption and reaction of O ＋ CN → OCN on Cu（100） are studied by using density functional theory and cluster model. Cu14 cluster model is used to simulate the surface. The calculated results show that the OCN species with the molecule perpendicular to the surface via N atom （N-down） is more favorable than other adsorption models, and the N-down at the bridge site is the most favorable. For N-down, calculated OCN symmetric and asymmetric stretching frequencies are all blue-shifted compared with the calculated values of free and in good agreement with the experiments. The charge transfer from the surface to the OCN species leads to that the bonding of OCN to the metal surface is largely ionic. The present studies also show that CN with the molecule perpendicular to the surface via C atom （NC-down） at the top site is the most stable. Except NC-down at the top site, the calculated CN stretching frequencies are all red-shifted. With O coadsorbed at the hollow site, the adsorption of NC-down at the next nearest bridge or top site is energetically more favorable than that at the adjacent hollow site. The reaction of O ＋ CN → OCN on Cu（100） has no energy barrier via both Eley-Rideal and Langmuir-Hinshelwood processes.

关键词： density functional theory adsorption and reaction cyanate,cyanide Cu(100) surface

Mechanical joint performances of friction self-piercing riveted carbon fiber reinforced polymer and AZ31B Mg alloy

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Journal of Magnesium and Alloys 2022年第12期10卷 3367-3379页

作者： Yuan Li yong Chae Lim jian Chen Jiheon jun Zhili Feng Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA

Carbon fiber reinforced polymer(CFRP) and AZ31B Mg alloy were joined by the friction self-piercing riveting(F-SPR) with different steel rivet shank sizes. With the increase of rivet shank size, lap shear fracture load and mechanical interlock distance increased. Ultrafine grains were formed at the joint in AZ31B as a result of dynamic recrystallization, which contributed to the higher hardness. Fatigue life of the CFRP-AZ31B joint was studied at various peak loads of 0.5, 1, 2, and 3 kN and compared with the resistance spot welded AZ31B-AZ31B from the open literature. The fatigue performance was better at higher peak load(>2 kN) and comparable to that of resistance spot welding of AZ31B to AZ31B at lower peak loads(<1 kN). From fractography, the crack initiation for lower peak load(<1 kN) case was observed at the fretting positions on the top and bottom surfaces of AZ31B sheet. When peak load was increased, fretting between the rivet and the top of AZ31B became more dominant to initiate a crack during fatigue testing.

关键词： Friction self-piercing riveting Magnesium alloy Carbon fiber reinforced polymer Dynamic recrystallization Fatigue life Crack initiation