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Detached-eddy simulations and analyses on new vortical flows over a 76/40° double delta wing

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Science China(Physics,Mechanics & Astronomy) 2013年第6期56卷 1062-1073页

作者： LI qin SUN dong ZHANG HanXin State Key Laboratory of Aerodynamics China and National Laboratory of CFD Beijing University of Aeronautics and Astronautics

Numerical simulations were performed on the massively separated flows of a 76/40° double delta wing using detached-eddy simulation(DES).A new type of cross-flow vortex is suggested.A vortex was initially generated near the junction of the strake and wing,which then moved towards the wing tip at certain wavelength and *** were made in detail on the mechanism of the generation of the cross-flow vortex,that is,the inviscid cross-flow instability which differs from that of the swept blunt ***-section topology of the cross-flow vortex is also investigated,and the wavelength of the vortex array and the characteristic frequency are *** analyses showed that the cross-flow vortices have an influence on the pressure distribution,which can cause a 10%-20% deviation from the averaged distribution.

关键词： double delta wing massively separated flows cross-flow instability vortex substructures DES

Urban natural gas demand and factors analysis in China:Perspectives of price and income elasticities

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Petroleum Science 2022年第1期19卷 429-440页

作者： Jia-Man Li Xiu-Cheng dong qin-Zhe Jiang Kang-yin dong School of International Trade and Economics University of International Business and EconomicsBeijing100029China UIBE Belt&Road Energy Trade and Development Center University of International Business and EconomicsBeijing100029China

Urban natural gas is becoming the main sector driving China’s natural gas consumption growth in recent *** study explores the impacts of urban natural gas price,wage,socioeconomic determinants,and meteorological conditions on urban natural gas demand in China over ***,this study also analyzes the potential regional heterogeneity and asymmetry in the impacts of gas price and income on China’s urban gas *** results reveal that:(1)The increased gas price can significantly reduce the urban gas demand,and the average income level may effectively promote the gas demand,also,a strong switching effect exists between electricity and natural gas in urban China;(2)these impacts are heterogeneous in regions among China,urban natural gas demand is largely affected by the gas price in regions with high-gas-price and by income in regions with low-gas-price;and(3)the impact of gas price on urban gas consumption is consistent in regions with different urban natural gas consumption,while the impact of income is *** study further provides several policy implications for improving the urban natural gas industry in China.

关键词： Urban natural gas demand Natural gas price Average wage Regional heterogeneity Asymmetry analysis

Tensile stress enhanced dynamic oxygen vacancies on interlayer stretched Bi_(2)O_(2)CO_(3) as pivotal knobs to promote sustainable selective CO_(2) photoreduction

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Journal of Energy Chemistry 2023年第8期83卷 173-179,I0006页

作者： Xian Shi Weidong Dai Xing'an dong qin Ren Ping yan Fan dong School of Chemistry and Environmental Engineering Sichuan University of Science&EngineeringZigong 643000SichuanChina Research Center for Carbon-Neutral Environmental&Energy Technology Institute of Fundamental and Frontier SciencesUniversity of Electronic Science and Technology of ChinaChengdu 611731SichuanChina State Centre for International Cooperation on Designer Low-Carbon and Environmental Materials(CDLCEM) School of Materials Science and EngineeringZhengzhou UniversityZhengzhou450001HenanChina College of Architecture and Environment Sichuan UniversityChengdu 610065SichuanChina

Surface oxygen vacancies(OVs) with abundant localized electrons on bismuth-oxygen based photocatalysts are proved to have the ability to capture and activate CO_(2).However,the surface OVs are easily filled with oxygen-containing species and destroyed,losing their effects as active sites and hindering the subsequent CO_(2)*** realistic and sustainable CO_(2)photoreduction,constructing sustainable and stable surface OVs as active sites on photocatalysts is *** work shows the synthesis of interlayer stretched Bi_(2)O_(2)CO_(3) ultrathin nanosheets with tensile stress,which are beneficial to continuously generating light-induced dynamic *** sufficient active sites,excellent,stable,and selective photoreduction of CO_(2)to CO under simulated solar light is *** light-induced OVs can reduce the energy barrier of rate-determining step,resulting in the 100% product *** results presented herein demonstrate the effect of dynamic OVs induced by interlayer tensile strain on catalysts for the enhanced selective CO_(2)photoreduction process.

关键词： Ultrathin Bi_(2)O_(2)CO_(3) Dynamic oxygen vacancies Product selectivity Charge transfer CO_(2) phororeduction

Microstructure and Mechanical Properties of Mg–3Al–Zn Magnesium Alloy Sheet by Hot Shear Spinning

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Acta Metallurgica Sinica(English Letters) 2020年第9期33卷 1226-1234页

作者： Fenghua Wang Peng Su Linxin qin Shuai dong yunliang Li Jie dong National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China Sinopec Northwest Oilfield Company Urumqi 830011China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Light Alloy Net Forming National Engineering Research Center Co.Ltd Shanghai 201615China

Hot shear spinning experiments with Mg–3.0 Al–1.0 Zn–0.5 Mn(AZ31 B, wt%) magnesium alloy sheets were conducted at various temperatures, spindle speeds and feed ratios to investigate the effects of these processing parameters on the microstructure, crystallographic texture and mechanical properties. The AZ31 B sheet displayed good shear formability at temperatures from 473 to 673 K, spindle speeds from 300 to 600 rev/min and feed ratios from 0.1 to 0.5 mm/rev. During the dynamic recrystallization process, the grain size and texture were affected by the deformation temperature of the hot shear spinning process. Each of the spun sheets presented a strong basal texture, and the c-axis of most of the grains was parallel to the normal direction. The optimal hot shear spinning parameters were determined to be a temperature of 473 K, a spindle speed of 300 rev/min and a feed ratio of 0.1 mm/rev. The yield strength, ultimate tensile strength and elongation in the rolled direction reached 221 MPa, 288 MPa and 14.1%, and those in the transverse direction reached 205 MPa, 280 MPa and 12.4%, respectively. The improved strength and decreased mechanical anisotropy resulted from the fine grain size and strong basal texture.

关键词： AZ31B magnesium alloy Shear spinning Texture Grain refinement

Generous or Selfish? Weighing Transaction Forwarding Against Malicious Attacks in Payment Channel Networks

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Journal of Computer Science & Technology 2022年第4期37卷 888-905页

作者： yi qin qin Hu dong-Xiao yu Xiu-Zhen Cheng School of Computer Science and Technology Shandong UniversityQingdao 266237China Department of Computer and Information Science Indiana University-Purdue University IndianapolisIndianapolis 46202U.S.A.

Scalability has long been a major challenge of cryptocurrency systems,which is mainly caused by the delay in reaching consensus when processing transactions *** an effective mitigation approach,the payment channel networks(PCNs)enable private channels among blockchain nodes to process transactions off-chain,relieving long-time waiting for the online transaction *** state-of-the-art studies of PCN focus on improving the efficiency and availability via optimizing routing,scheduling,and initial deposits,as well as preventing the system from security and privacy ***,the behavioral decision dynamics of blockchain nodes under potential malicious attacks is largely *** fill this gap,we employ the game theory to study the characteristics of channel interactions from both the micro and macro perspectives under the situation of channel depletion *** study is progressive,as we conduct the game-theoretic analysis of node behavioral characteristics from individuals to the whole population of *** analysis is complementary,since we utilize not only the classic game theory with the complete rationality assumption,but also the evolutionary game theory considering the limited rationality of players to portray the evolution of *** results of numerous simulation experiments verify the effectiveness of our analysis.

关键词： blockchain payment channel network game theory

Revealing the scientific connotation of compatibility of Chinese medicine medica based on self-assembly technology

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Journal of Traditional Chinese Medicine 2024年第6期44卷 1288-1295页

作者： dong yingying GUO qin GAO yuan WANG Huanhuan BAI dong Institute of Basic Theory of Chinese Medicine China Academy of Chinese Medical SciencesBeijing 100700China Basic Medical School Shaanxi University of Chinese MedicineXianyang 712046China

Chinese materia medica(CMM) compatibility is one core content in the theory of Traditional Chinese Medicine(TCM), and elaborating the scientific connotation of CMM compatibility is of great significance to promote the modernization of TCM. Self-assembly is the combination of active ingredients into aggregates through noncovalent bonds, such as hydrogen bonding, electrostatic interactions, ionic interactions, and hydrophobic interactions. The complex properties and special structures of CMM components create the basis for selfassembly. The self-assembled materials formed after CMM compatibility is an important part of the material basis for the efficacy of TCM, which can help explain the scientific connotations of CMM compatibility. This review summarizes the self-assembly phenomenon from the perspective of drug pair combinations in recent decades and explains the scientific connotation of CMM compatibility about the material basis, pharmacodynamic changes, and mechanism of action, providing new ideas and methods for the study of TCM.

关键词： Chinese materia medica compatibility medicine Chinese Traditional self-assembly phenomenon reduce adverse reactions and increase desired effects component interactions review

Thermal comfort assessment in civil aircraft cabins

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Chinese Journal of Aeronautics 2014年第2期27卷 210-216页

作者： Pang Liping qin yue Liu dong Liu Meng School of Aviation Science and Engineering Beihang University

Aircraft passengers are more and demanding in terms of thermal comfort. But it is not yet easy for aircraft crew to control the environment control system （ECS） that satisfies the thermal comfort for most passengers due to a number of causes. This paper adopts a corrected predicted mean vote （PMV） model and an adaptive model to assess the thermal comfort conditions for 31 investigated flights and draws the conclusion that there does exist an uncomfortable thermal phe- nomenon in civil aircraft cabins, especially in some short-haul continental flights. It is necessary to develop an easy way to predict the thermal sensation of passengers and to direct the crew to con- trol ECS. Due to the assessment consistency of the corrected PMV model and the adaptive model, the adaptive model of thermal neutrality temperature can be used as a method to predict the cabin optimal operative temperature. Because only the mean outdoor effective temperature ET＊ of a departure city is an input variable for the adaptive model, this method can be easily understood and implemented by the crew and can satisfy 80-90% of the thermal acceptability levels of passen- gers.

关键词： Adaptive model of thermalneutrality temperature Civil aircraft cabin Mean outdoor effectivetemperature Optimal operativetemperature PM~ Thermal comfort assessment

An anchor-based spectral clustering method

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Frontiers of Information Technology & Electronic Engineering 2018年第11期19卷 1385-1396页

作者： qin ZHANG Guo-qiang ZHONG Jun-yu dong Department of Computer Science and Technology Ocean University of China Science and Information College Qingdao Agricultural University

Spectral clustering is one of the most popular and important clustering methods in pattern recognition,machine learning, and data mining. However, its high computational complexity limits it in applications involving truly large-scale datasets. For a clustering problem with n samples, it needs to compute the eigenvectors of the graph Laplacian with O(n^3) time complexity. To address this problem, we propose a novel method called anchor-based spectral clustering(ASC) by employing anchor points of data. Specifically, m(m≤n) anchor points are selected from the dataset, which can basically maintain the intrinsic(manifold) structure of the original data. Then a mapping matrix between the original data and the anchors is constructed. More importantly, it is proved that this data-anchor mapping matrix essentially preserves the clustering structure of the data. Based on this mapping matrix, it is easy to approximate the spectral embedding of the original data. The proposed method scales linearly relative to the size of the data but with low degradation of the clustering performance. The proposed method, ASC,is compared to the classical spectral clustering and two state-of-the-art accelerating methods, i.e., power iteration clustering and landmark-based spectral clustering, on 10 real-world applications under three evaluation *** results show that ASC is consistently faster than the classical spectral clustering with comparable clustering performance, and at least comparable with or better than the state-of-the-art methods on both effectiveness and efficiency.

关键词： Clustering Spectral clustering Graph Laplacian Anchors

Formation of adiabatic shearing band for high-strength Ti-5553 alloy:A dramatic thermoplastic microstructural evolution

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Defence Technology（防务技术） 2022年第11期18卷 2045-2051页

作者： dong-yang qin ying-gang Miao yu-long Li School of Aeronautics Northwestern Polytechnical UniversityXi'an710072China School of Civil Aviation Northwestern Polytechnical UniversityXi'an710072China

By using split Hopkinson pressure bar, optical microscopy and electronic microscopy, we investigate the influence of initial microstructures on the adiabatic shear behavior of high-strength Ti-5Al-5V-5Mo-3Cr(Ti-5553) alloy with lamellar microstructure and bimodal microstructure. Lamellar alloy tends to form adiabatic shearing band(ASB) at low compression strain, while bimodal alloy is considerably ASBresistant. Comparing with the initial microstructure of Ti-5553 alloy, we find that the microstructure of the ASB changes dramatically. Adiabatic shear of lamellar Ti-5553 alloy not only results in the formation of recrystallized β nano-grains within the ASB, but also leads to the chemical redistribution of the alloying elements such as Al, V, Cr and Mo. As a result, the alloying elements distribute evenly in the *** contrast, the dramatic adiabatic shear of bimodal alloy might give rise to the complete lamination of the globular primary a grain and the equiaxial prior β grain, which is accompanied by the dynamic recrystallization of a lamellae and β lamellae. As a result, ASB of bimodal alloy is composed of a/β nanomultilayers. Chemical redistribution does not occur in ASB of bimodal alloy. Bimodal Ti-5553 alloy should be a promising candidate for high performance armors with high mass efficiency due to the processes high dynamic flow stress and excellent ASB-resistance.

关键词： Titanium alloys Armor High loading rate Adiabatic shearing band Dynamic phase transformation