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NUMERICAL STUDY OF VORTEX SHEDDING FROM A SQUARE CYliNDER AND ITS EFFECTS ON HEAT TRANSFER OF MIXED CONVECTION

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Journal of Hydrodynamics 2003年第3期15卷 103-111页

作者： Zhang Ning, li guang-zheng, huang jian-chun College of Civil Engineering and Mechanics, Huazhong University of Science and Technology, Wuhan 430074, China, College of Civil Engineering and Mechanics Huazhong University of Science and Technology Wuhan 430074 China

The influence of buoyancy on vortex shedding from a heated square cylinderand its effects on the heat transfer of mixed convection were simulated. The flow equations, basedon the velocity and the pressure, were solved along with the energy equation by a modified SIMPLERalgorithm - the Quick Scheme and small Control Volume (QSCV) algorithm developed by the authors ofthe present paper. A set of optimized computational domain and artificial lateral boundaryconditions were used along with the QSCV algorithm. Several cases were simulated for the Grashofnumbers up to 1. 8 X 10~5, the Reynolds numbers up to 500, and a range of angles between free streamvelocity and gravity from 0 to 1.5π. In opposing flow, the results distinguish two different flowpatterns: periodic flow for Gr Gr_c, anda precise correlation between Gr_c and Re expressed as Gr_c = 0. 00166(Re)^(2.97795) for Re up to500 was firstly obtained. In cross flow, it could be seen that the Ri = Gr/Re^2 plays a great rolein the wake vortex patterns and the temperature fields. In aiding flow, it is found that the mainflow currents cause a large expansion of the streamlines and isotherms in the direction normal tothe free stream velocity. These changes in the wake vortex patterns and the temperature fieldsgreatly modify the heat flux along the surface of the square cylinder and consequently, the heattransfer rate is strongly dependent upon the Reynolds numbers, the Grashof numbers, and the gravitydirection.

关键词： buoyancy mixed convection vortex shedding numerical simulation

Synthesis, Photoluminescence and Photocatalytic Performance of BiPO4 with Different Phase Structures

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Chemical Research in Chinese Universities 2013年第3期29卷 556-562页

作者： WANG Yun-jian li li-ping zheng Jing huang Xin-song li guang-she State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences Fuzhou 350002 P. R. China Graduate University of Chinese Academy of Sciences Beijing 100049 P. R. China

Three kinds of crystal phase BiPO4（HP, LTBP, and HTBP） were selectively synthesized by controlling the preparation conditions. Structures of the three samples are all constructed by PO4 and BiO8 polyhedra but with different geometric structures. Detailed characterization was carried out by X-ray diffraction（XRD）, scanning eletron microscopy（SEM） and Raman, UV-Vis, and luminescence spectrometries. Three samples exhibit huge distinctions in their photoluminescence（PL） lifetime： 0.68, 162 and 160 μs for HP, LTBP, and HTBP, respectively. More interesting, an outstanding photocatalytic activity is observed for as-prepared LTBP nanorod, which shows even higher activity for the degradation of MB solution than P25. In addition, experiments were carried out to clarify the role of hydroxyl （OH） and superoxide radicals（O2·） played in photocatalytic process and it was found O2·was the main active species in BiPO4 photocatalysts. Further comparison of structural and photocatalytic properties of the three samples finds that structure distortion is contributed to their property difference. A correlation was found between photocatalytic performance and the distortion of BiO8 dodecahedra. The internal field generated by the distortion of BiO8 dodecahedra was believed advantageous for the separation of electron and hole, which was in favor of the improvement of photocatalytic activity. This correlation may help to design other photocatalysts with high activity.

关键词： BiPO4 Photoluminescence Photocatalysis -

Experimental research on semi-coke for blast furnace injection

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Journal of Iron and Steel Research International 2021年第4期28卷 391-401页

作者： chun-chao huang Xiao-jun Ning guang-wei Wang jian-liang Zhang zheng-fu Peng Hai-peng Teng State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Guanzhuang Campus University of Science and Technology BeijingBeijing 100083China

The combustion properties and grindability of Shenmu low-rank coal(SM)and its four different semi-cokes were studied by the self-designed equipment and Hardgrove *** four semi-cokes were obtained under the pyrolysis temperature of 400,500,600 and 700℃,named as SM-400,SM-500,SM-600 and SM-700,*** analyses of nitrogen adsorp-tion,Fourier-transform infrared spectroscopy(FTIR)spectra and Raman spectra were carried out to explain the change in combustion ratio and *** result showed that the specific surface area of samples had an essential effect on the combustion ratio of SM-400 and ***,the grindability depended on the strength of coal matrix,and the augment of pore amounts would increase the *** functional groups and graphitization degree of the same sam-ple were identical with the combustion *** the pyrolysis upgrading temperature increasing,the combustion ratio of sample decreased,corresponding to the decrease in the benzene ring and the increase in graphitization *** addition,the thermogravimetric analysis was carried out,and the result was compared against what was shown in the data of com-bustion *** pulverized coal injection,the combustion ratio was more intuitive and more accurate than combustibility.

关键词： Semi-coke Combustion ratio Functional group Graphitization degree Grindability

liquid crystal character controlled by complementary discotic molecules mixtures： Columnar stacking type and mesophase temperature range

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Chinese Chemical Letters 2016年第3期27卷 475-480页

作者： Yan li Ming-guang li Ya-Jun Su jian-Gang liu Yan-chun Han Shi-Jun zheng li-Xiang Wang State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China University of the Chinese Academy of Sciences Beijing 100049 China School of Materials Science and Engineering Zhengzhou University Zhengzhou 450052 China

In this work, the mesophase properties were tuned via mixing two discotic molecules with structural complementarity. Compared with the liquid crystalline hexakis（n-hexyloxy）triphenylene（H6TP）materials（columnar hexagonal phase from 53 ℃ to 91 ℃）, mesophase types as well as phase transition temperatures varied with the introduction of crystalline hexaazatriphenylene derivative（PBH）molecules. The introduction of less than 33% amount of PBH disrupted the columnar hexagonal phase formed by H6 TP remarkably, followed by the decreased clearing temperatures of liquid crystals. As the PBH amount was further increased, the destroyed columnar hexagonal phase was turned into the columnar rectangular phase, in which H6 TP and PBH molecules together formed the columnar mesophase. The formation of new mesophase contributed to the enlarged mesophase temperature（from44 ℃ to 144 ℃）. We speculated that the alkyl chains interaction induced by the PBH component competed with the strong p–p stacking between H6 TP molecules, thus altering the liquid crystalline properties including mesophase types and phase transition temperatures.

关键词： Alkyl chains packing Mesophase type liquid crystals Phase transitions Mixture

Control and Patterning of Various Hydrophobic Surfaces:Insitu Modification Realized by Flexible Atmospheric Plasma Stamp Technique

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Journal of Bionic Engineering 2020年第3期17卷 436-447页

作者： Nan Zhang chun huang Jiaqian li ling Kang Huanxi zheng Yaqin He Zuankai Wang Xiaofeng Zhou jian Zhang Shanghai Key Laboratory of Multidimensional Information Processing School of Communication and Electronic EngineeringEast China Normal UniversityShanghai 200241China Department of Mechanical Engineering City University of Hong KongHong Kong 999077China Shanghai Institute of Intelligent Electronics Systems Fudan UniversityShanghai 200433China

Wettability plays a vital role in fundamental researches and practical *** control and patterning have been widely studied in various *** researches have grown rapidly,the methods are still restricted by limitations including complicated processes,high equipment requirements and shortage of methods to treat complex *** we report a simple,low cost,array-based wettability control and patterning method via in-situ modification by flexible plasma *** control and patterning on surfaces of superhydrophobic aluminum,superhydrophobic PDMS and silicon,even plant leaf and fruit are *** relationships between the wettability and the treatment time are *** elucidate that the wetting states can also be *** surface modification mechanism of in-situ plasma treatment is further *** the step by step treatment,gradient and arbitrary wettability patterning on surfaces have been ***,the patterned wettability on the inner surface of a tube has been realized,which has never been ***,in-situ wettability patterning is applied to achieve microfluidics channels on the inner surface of superhydrophobic *** work will bring new insights into the study of wetting field and stimulate more applications on wettability control and patterning.

关键词： wettability control patterning in-situ modification flexible plasma stamp atmospheric

Mechanical properties and surface characteristics of SiC fibers irradiated by swift heavy ions

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Nuclear Science and Techniques 2022年第9期33卷 37-47页

作者： li-Qing Zhang Chong-Hong Zhang Chen-chun Hao Guo-Dong Hu zheng-Dong Feng Yong-jian Tang Wen-Kun Zhu jian-Yang li Qing huang Southwest University of Science and Technology Mianyang 621010China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China

SiC fibers were irradiated by 414.4-MeV^(112)Sn^(27.3+)ions to different fluences(5.0×10^(12),6.0×10^(13),1.6×10^(14),and 1.92×10^(15)ions/cm^(2)).^(112)Sn^(27.3+)deposited its energy mainly via electron energy loss and passed through the SiC ***,the mechanical properties and surface characteristics of fibers were studied using a specific single filament tensile test and field emission scanning electron *** revealed that the carbon concentration on the fiber surface increased while the silicon concentration ***,the addition of oxygen was found to correlate with an increase in ion ***,the fiber surface morphology of the least fluence(5.0×10^(12)ions/cm^(2))irradiated specimen displayed no obvious changes and its diameter was slightly *** successive increases of ion fluence,large grains/bubbles on the fiber surface first appeared and then disappeared,and the diameter of fibers evidently ***,at the highest fluence(1.92×10^(15)Sn ions/cm^(2))irradiated specimen,some fibers were brittle *** a result,the mean tensile strength and the average elastic modulus of the fibers generally decreased with respect to the ion *** degradation mechanisms of mechanical properties of SiC fibers under irradiation are discussed in detail.

关键词： SiC fibers Swift-heavy-ion irradiation FE SEM Tensile test

Effects of Estrogen on ER, NGF, and ChAT Expression in Cerebellum of Aging Female Sprague-Dawley Rat

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Agricultural Sciences in China 2007年第3期6卷 368-374页

作者： CHEN zheng-li FAN guang-li LUO Qi-hui ZHU chun-mei huang Yi-dan College of Animal Science and Technology Northwest A＆F University Yangling 712100 P.R.China College of Animal Science and Technology Sichuan Agricultural University Yaan 625014 P.R.China

This article discusses the effects of estrogen on the expression of estrogen receptor （ER）, nerve growth factor （NGF）, and choline acetyltransferase （CHAT） in the cerebellum of rats. The model of aging female rat was established to study the expression and distribution of ER, NGF, and ChAT in the cerebellum following 17β-estradiol treatment using the technique of immunohistochemical ultrasensitive SP in sprague-dawley rat. The immunoreactive productions were distributed in stratum Purkinje cell, nucleus dentatus, nucleus interpositus, and nucleus fastigii of cerebellum, and the ER positive production was mainly located in the plasma, cytoplasmic membrane, and neurite, and also existed in nucleus. The general tendency of the expression of ER, NGF, and ChAT positive production in the cerebellum cortex and nuclei of aging rat significantly decreases, while the intensity and quantity of the immunoreactive production ascends predominantly after 17β-estradiol treatment. Simultaneously, the positive neurite of Purkinje cell shows a similar tendency. The above- mentioned results suggest that the estrogen upregulates the expression of NGF and CHAT, and plays a vital role in sustaining and protecting the structure and function of cerebellum neurons. Furthermore, the similarity of their changing tendency implies that they were correlated and cooperated during the course in effect of estrogen on cerebellum. It also showed that the action of estrogen in cerebellum could be via genomic and nongenomic mechanism.

关键词： estrogen receptor (ER) nerve growth factor (NGF) choline acetyltransferase (CHAT) immunohistochemical ultrasensitive SP cerebellum rat

Interfacial Improvement of Carbon Fiber/Epoxy Composites by Incorporating Superior and Versatile Multiscale Gradient Modulus Intermediate Layer with Rigid-flexible Hierarchical Structure

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Chinese Journal of Polymer Science 2021年第7期39卷 896-905页

作者： Pei-Feng Feng Guo-Jun Song Wen-jian Zhang Hao zheng Bo-Wen li Shao-Feng Zhou Ya-Qing liu guang-Shun Wu li-chun Ma Institute of Polymer Materials School of Material Science and EngineeringQingdao UniversityQingdao 266071China Shanxi Province Key Laboratory of Functional Nanocomposites North University of ChinaTaiyuan 030000China School of Chemistry and Materials Science Ludong UniversityYantai264025China

In order to enhance the interfacial adhesion of carbon fiber(CF)and polymer matrix,a multiscale gradient modulus intermediate layer with rigid-flexible(GO-PA)hierarchical structure was designed and fabricated between CFs and matrix by a facile and businesslike *** polarity,roughness and wettability of CFs surface as well as the thickness of intermediate layer in composite have been significantly increased after rigid-flexible hierarchical structure was *** IFSS,ILSS,compression and impact toughness manifested that the hierarchical structure could bring about a fantastic improvement(76.8%,46.4%,40.7%and 37.8%)for the interfacial and mechanical properties than other previous ***,the establishment of CF surface with gradient modulus rigid-flexible hierarchical structure via regulation of nanoparticles and polymer array would open a new,viable and promising route to obtaining high-performance composites.

关键词： Carbon fibers Polymer-matrix composites Interface Hierarchical structure Gradient modulus

Effect of heat treatment on microstructure,mechanical and tribological properties of in-situ (TiC+TiB)/TC4 composites by casting

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China Foundry 2023年第3期20卷 207-217页

作者： Bo-wen zheng Shuai Chen chun-yu Yue Xue-jian lin Fu-yu Dong Hong-jun huang Xiao-jiao Zuo Yin-xiao Wang Xiao-guang Yuan School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

To enhance the performance of in-situ synthesized 6vol.%(Ti C+Ti B)/TC4 titanium matrix composites fabricated by casting,a variety of heat treatment processes were carried *** conducting microstructure observations following various heat treatments,it was found that the composites exhibit a basketweave microstructure,consisting of an α phase and a transformed β *** sizes of(α+β) phases were found to be refined to varying degrees after the heat treatment processes,while the morphology of Ti B remains largely unchanged and Ti C becomes *** testing revealed that all composites subjected to different heat treatments demonstrate a notable increase in ultimate compressive strength as well as a slight improvement in plasticity compared to the as-cast *** results of the tribological performance test indicated that the heat-treated composites exhibit lower average friction coefficient,specific wear rate,and worn surface roughness compared to the as-cast *** the heat treatment processes studied,the composite solution heated at 1,150 °C/1 h followed by air cooling,then 950 °C/1 h followed by air cooling,and finally 500 °C/4 h followed by air cooling,demonstrates the highest levels of hardness,compressive strength,and wear *** improvements are attributed to the combined effects of solid solution strengthening,grain refinement,and the pinning of dislocation slip.

关键词： titanium matrix composites heat treatment mechanical properties tribological properties