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Computational Study on the Boundary Layer Suction Effects in the Supersonic Compressor Flow with a Bowed Blade

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Journal of Thermal Science 2022年第2期31卷 511-528页

作者： cao Zhiyuan SONG Cheng GAO Xi ZHANG xiang LIU Bo School of Power and Energy Northwestern Polytechnical UniversityXi'an 710072China

Flow control methodologies have been widely used to eliminating flow separation and increasing the blade load in axial *** at revealing the flow mechanism of coupled bowed blading and boundary layer suction in a supersonic compressor cascade,a cascade with a diffusion coefficient of 0.62 is numerically *** of all,according to the available experimental data,the numerical method was validated;then,different bowed blading effects on flow field in detail were investigated;at last,based on the flow physics of purely bowed blading,the positively bowed blade was coupled with boundary layer suction on blade suction surface,whereas the negatively bowed blade was coupled with endwall *** coupled control method,influence mechanism on flow field,especially on the shock structure was revealed,and different aspect ratios of coupled control method were investigated as *** showed that the coupled positively bowed blading and suction surface suction can eliminate the flow separation *** with that of baseline supersonic cascade,the total pressure loss coefficient of the coupled scheme was reduced by 37.4%at *** mid-span,the shock moved downstream and the single shock was separated to a dual-shock structure since the positively bowed blading reduced the static pressure of *** coupled negatively bowed blading and endwall suction also effectively enhanced the performance of cascade by removing the corner separation,with the loss coefficient reduced by as much as 41.9%.However,the suction coefficient of optimal coupled negatively bowed blading scheme reached 10.5%,which is too high for practical *** coupled control,the 3 D shock structure became“C”shaped distribution along spanwise because of the difference in influence mechanism of negatively bowed blading on different spanwise *** to the opposite influence effect of positively and negatively bowed blading,the shock structure in the two different sc

关键词： supersonic compressor cascade bowed blading boundary layer suction shock aspect ratio

Blade Lean and Tip Leakage Flows in Highly Loaded Compressor Cascades

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Journal of Thermal Science 2021年第4期30卷 1388-1405页

作者： cao Zhiyuan SONG Cheng ZHANG xiang GAO Xi LIU Bo School of Power and Energy Northwestern Polytechnical UniversityXi’an 710072China

Blade lean has been intensively utilized in axial *** this study,three families of highly loaded compressor cascades featuring different aspect ratios(AR)with different levels of blade lean were designed and simulated with and without tip *** influences of blade lean on corner separation and tip leakage flow(TLF)were *** show that blade lean can exert spanwise pressure gradient confined to the fore part,spanwise mass flow rate re-distribution exhibiting differently at fore and rear part of blade,and stage reaction *** has a significant influence on blade *** the increase of AR,corner separation grows significantly and requires a higher lean level to be *** eliminates corner separation of linear cascades but also increases the loss of leaned cascades;blade lean introduces 22%higher tip leakage mass flow,but exhibits 43%(blade M)and 38%(blade E)lower tip leakage *** flow mechanism can be mainly accounted by the reduction of bulk flow velocity,tip leakage velocity and the velocity difference near leading edge(LE).High AR cascade induces re-distribution of TLF along blade chord and reduces leakage loss compared with low AR counterpart.

关键词： axial compressor leaned blade tip leakage flow aspect ratio corner separation

Darboux integrability and algebraic limit cycles for a class of polynomial differential systems

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Science China Mathematics 2014年第4期57卷 775-794页

作者： cao JinLong LLIBRE Jaume ZHANG xiang Department of Mathematics Shanghai Jiao Tong University Departament de Matemàtiques Universitat Autònoma de Barcelona Ministry of Education Key Lab of Scientific and Engineering Computing Shanghai Jiao Tong University

This paper deals with the existence of Darboux first integrals for the planar polynomial differential systems x=x-y+P n+1(x,y)+xF2n(x,y),y=x+y+Q n+1(x,y)+yF2n(x,y),where P i(x,y),Q i(x,y)and F i(x,y)are homogeneous polynomials of degree *** this class,we identify some new Darboux integrable systems having either a focus or a center at the *** such Darboux integrable systems having degrees 5and 9 we give the explicit expressions of their algebraic limit *** the systems having degrees 3,5,7 and 9and restricted to a certain subclass we present necessary and sufficient conditions for being Darboux integrable.

关键词： Darboux first integral algebraic limit cycles Abel differential equation

Effect of Mg addition on TiN inclusions in GCr15 bearing steel

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Journal of Iron and Steel Research International 2022年第6期29卷 925-938页

作者： Lei cao Guo-cheng Wang Yuan-you Xiao rong-guang Yang School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina Key Laboratory of Metallurgy Engineering Liaoning Province University of Science and Technology LiaoningAnshan 114051LiaoningChina Steel Rolling Department Shougang Jingtang United Iron and Steel Co.Ltd.Tangshan 063200HebeiChina

Compared with the original GCr15 bearing steel,TiN inclusions are greatly reduced by the effect of Mg addition,and many different types of non-metallic Mg-containing inclusions were observed in Mg-treated GCr15 bearing steel which includes MgO,MgS·MnS,MgO–MgS·MnS,MgAl_(2)O_(4)–MgS·MnS,MgO–TiN,MgS·MnS–TiN,and MgO–MgS·MnS–*** inclusion size distribution based on automatic inclusion analysis software shows that the number of inclusion with the size ranging from 1 to 3μm increases obviously because a large amount of MgO,MgS·MnS,TiN inclusions containing Mg with smaller sizes are massively *** situ observation on the experimental steel by high-temperature confocal laser scanning microscopy confirms that MgO can provide nucleation sites for *** addition,the MgS·MnS and MgO–MgS·MnS inclusions can also provide positions for the nucleation of *** calculations indicate that after Mg addition to liquid steel,a large number of fine MgO inclusions are generated in the liquid steel because of the strong reactivity of Mg and *** the same time,MgS precedes TiN precipitates in the solid–liquid two-phase region;thus,MgO and MgS·MnS can provide sites for TiN *** last,two possible formation pathways for the above various TiN inclusions containing Mg are discussed.

关键词： Mg treatment GCr15 bearing steel TiN inclusion Size distribution In situ observation

miR-10b promotes porcine immature Sertoli cell proliferation by targeting the DAZAP1 gene

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Journal of Integrative Agriculture 2019年第8期18卷 1924-1935页

作者： WENG Bo RAN Mao-liang cao rong PENG Fu-zhi LUo Hui GAo Hu TANG xiang-wei YANG An-qi CHEN Bin College of Animal Science and Technology/Hunan Provincial Key Laboratory for Genetic Improvement of Domestic Animal Hunan Agricultural University

MicroRNAs(miRNAs) have been widely identified in porcine testicular tissues and implicated as crucial regulators of proliferation, apoptosis, and differentiation in porcine spermatogenesis related cells. However, the function roles of most of the miRNAs that have been identified in Sertoli cells are poorly understood. In the present study, six experiments were conducted to study the regulatory role of miR-10b in porcine immature Sertoli cells. In experiment 1, the results showed that the relative mRNA expression level of miR-10b in porcine testicular tissues decreased quadratically(P0.05) on porcine immature Sertoli cell apoptosis. In experiment 6, the co-transfection treatment results showed that miR-10b promoted(P<0.05) porcine immature Sertoli cell proliferation by targeting DAZAP1 gene. Overall, these experiments demonstrated that miR-10b promotes porcine immature Sertoli cell proliferation by targeting the DAZAP1 gene.

关键词： miR-10b DAZAP1 gene expression proliferation porcine immature Sertoli cell

Efficient construction of calcium fluoride nanoaggregates for enhanced water vapor adsorption

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Particuology 2024年第6期89卷 191-197页

作者： Dan-Lei Yang Jing cao rong-Kun Liu Jie-Xin Wang School of Life Sciences and Chemical Engineering Jiangsu Second Normal UniversityNanjing210013China State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China Research Center of the Ministry of Education for High Gravity Engineering and Technology Beijing University of Chemical TechnologyBeijing100029China Petrochemical Research Institute PetroChinaBeijing102206China

Calcium fluoride(CaF_(2))is an ideal adsorbent for the dehydration of gaseous hydrogen fluoride(HF)containing water *** this work,a novel CaF_(2)absorbent,spherical CaF_(2)nanoaggregates(NAs)with a closely packed structure,was proposed and efficiently fabricated by spray drying *** the building blocks of CaF_(2)NAs,the CaF_(2)nanoparticles(NPs)were prepared by the addition of excess calcium ions(Ca^(2+))or fluorine ions(F−)in the *** results indicated that the CaF_(2)NPs synthesized by excess Ca^(2+)and the corresponding NAs exhibited much better water vapor adsorption properties than their counterparts by excess F−,owing to higher zeta *** importantly,whether excess Ca^(2+)or F^(−),CaF_(2)NAs had further enhanced water vapor adsorption capacity compared to primary CaF_(2)NPs,possibly owing to their unique nano-micro secondary structures and higher surface *** work has great potential in the development of high-performance absorbents for separating moisture from corrosive gas HF.

关键词： CaF_(2)nanoaggregates Water vapor adsorption Spray drying

Experimental study on interaction mechanism of small H-beams and a soil-cement retaining wall

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Journal of China University of Mining and Technology 2008年第1期18卷 149-152页

作者： WANG Suo-rong cao Bao-fei jiangsu Changzhou Higher Vocational School of Construction Changzhou Jiangsu 213016 China jiangying Polytechnic College Jiangyin Jiangsu 214400 China

Small H-beams such as the No.14-20 I-steel can be inserted into soil-cement retaining walls to form small H-beam soil-cement compound walls, functioning both as a retaining wall and a cutoff wall for braced structure excavations. Being different from the mixed soil-cement wall （SMW）, the interaction between soil-cement and small H-steel is very good. We have carried out a series of bending experiments on small H-beams in soil-cement model compound beams to study the mechanism of interactions. The results show that the interaction between H-beams and soil-cement is very good, whether the H-beam is single or double. Joint forms of double H-beams at one end have little effect on both the contribution coefficient and on ultimate deflection before cracking. But after cracking, the joint forms greatly affect the contribution coefficient. We conclude that the rigid joint girder for double H-beams is a better choice in oractice.

关键词： small H-steel soil-cement compound beam rigidity contribution coefficient ultimate deflections soil type experi-mental study

Engagement in outdoor physical activity under ambient fine particulate matter pollution: A risk-benefit analysis

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Journal of Sport and Health Science 2022年第4期11卷 537-544页

作者： Ruopeng An Hyojung Kang Lianzhong cao Xiaoling xiang Brown School Washington UniversitySt.LouisMO 63130USA Department of Kinesiology and Community Health University of IllinoisChampaignIL 61820USA School of Management and Journalism Shenyang Sport UniversityShenyang 110102China School of Social Work University of MichiganAnn ArborMI 48109USA

Background:Outdoor physical activity(PA)brings important health benefits,but exposure to polluted air increases health *** study aimed to quantify the tradeoff of PA under fine particulate matter(PM_(2.5))air pollution by estimating the optimal PA duration under various pollution ***:A risk-benefit analysis was performed to estimate the optimal outdoor moderate-intensity PA(MPA)duration under varying PM_(2.5) ***:An inverse nonlinear relationship was identified between optimal MPA duration and background PM_(2.5) concentration *** background PM_(2.5) concentration increased to 186 μg/m^(3),the optimal outdoor MPA duration decreased to 2.5 h/week,the minimum level recommended by current PA *** background PM_(2.5) concentration further increased to 235 μg/m^(3),the optimal outdoor MPA duration decreased to 1 h/*** relationship between optimal MPA duration and background PM_(2.5) concentration levels was stronger when exercising at a location closer to a source of air *** to the general adult population,adults aged 60 years and older had substantially steeper curves—the optimal outdoor MPA duration decreased to 2.5 h/week when background PM_(2.5) concentration reached 45 μg/m^(3).Conclusion:The health benefit of outdoor MPA by far outweighs the health risk of PM_(2.5) pollution for the global average urban background concentration(22 μg/m^(3),).This modeling study examined a single type of air pollutant and suffered from measurement errors and estimation *** research should examine other air pollutants and indoor PA,incorporate short-and mid-term health effects of MPA and air pollution into the risk-benefit analysis,and provide estimates specific for high-risk subgroups.

关键词： Air pollution Exercise Physical activity PM_(2.5) Risk-benefit analysis

An Encrypted Image Retrieval Method Based on SimHash in Cloud Computing

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Computers, Materials & Continua 2020年第4期63卷 389-399页

作者： Jiaohua Qin Yusi cao Xuyu xiang Yun Tan Lingyun xiang Jianjun Zhang College of Computer Science and Information Technology Central South University of Forestry&TechnologyChangsha410004China School of Computer and Communication Engineering Changsha University of Science and TechnologyChangsha410114China College of Engineering and Design Hunan Normal UniversityChangsha410012China

With the massive growth of images data and the rise of cloud computing that can provide cheap storage space and convenient access,more and more users store data in cloud ***,how to quickly query the expected data with privacy-preserving is still a challenging in the encryption image data *** this goal,this paper proposes a ciphertext image retrieval method based on SimHash in cloud ***,we extract local feature of images,and then cluster the features by *** on it,the visual word codebook is introduced to represent feature information of images,which hashes the codebook to the corresponding ***,the image feature vector is generated by SimHash searchable encryption feature algorithm for similarity *** experiments on two public datasets validate the effectiveness of our ***,the proposed method outperforms one popular searchable encryption,and the results are competitive to the state-of-the-art.

关键词： Cloud computing SimHash encryption image retrieval K-means