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Application of deep learning method to Reynolds stress models of channel flow based on reduced-order modeling of DNS data

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Journal of Hydrodynamics 2019年第1期31卷 58-65页

作者： Zhen Zhang Xu-dong Song Shu-ran Ye yi-wei Wang Chen-guang Huang yi-ran An Yao-song Chen Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China College of Engineering Science University of Chinese Academy of SciencesBeijing 100049China College of Engineering Peking UniversityBeijing 100871China

Recently,the methodology of deep learning is used to improve the calculation accuracy of the Reynolds-averaged Navier-Stokes (ranS) *** this paper,a neural network is designed to predict the Reynolds stress of a channel flow of different Reynolds *** rationality and the high efficiency of the neural network is validated by comparing with the results of the direct numerical simulation (DNS),the large eddy simulation (LES),and the deep neural network (DNN) of other *** further enhance the prediction accuracy,three methods are developed by using several algorithms and simplified models in the neural *** the method *** regularization is introduced and it is found that the oscillation and the overfitting of the results are eflectively *** the method 2,y^+ is embedded in the input variable while the combination of the invariants is simplified in the method *** the predicted results,it can be seen that by using the first two methods,the errors are ***,the method 3 shows considerable advantages in the DNS trend and the smoothness of a ***,it is concluded that the DNNs can predict effectively the anisotropic Reynolds stress and is a promising technique of the computational fluid dynamics.

关键词： Deep neural network channel flow turbulence model Reynolds stress

Energy flexibility and resilience analysis of demand-side energy efficiency measures within existing residential houses during cold wave event

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Building Simulation 2024年第7期17卷 1043-1063页

作者： Xiaoyi Zhang Fu Xiao Yanxue Li yi ran Weijun Gao Innovation Institute for Sustainable Maritime Architecture Research and Technology Qingdao University of TechnologyQingdaoChina Department of Building Environment and Energy Engineering The Hong Kong Polytechnic UniversityHong KongChina Faculty of Environmental Engineering The Universityof KitakyushuKitakyushuJapan

Using the behind-meter data,this study applied a comparison and optimization-based framework to evaluate the energy flexibility and resilience of distributed energy resources within existing houses during cold wave *** analysis demonstrates the effectiveness of high envelope insulation level in improving energy resilience,identifies impacts of distributed energy resources on variations of household electricity ***,a 14.6%reduction in the median value of the normalized load of building group with low U-values,implementations of cogeneration system effectively suppressed variations of electricity *** energy performances of on-site generators are evaluated based on high resolution data,energy flexibility of domestic hot water and thermostatically controlled loads were investigated through built demand response *** reveal that electrifying hot water demand offers additional power flexibility,the integration of fuel cell cogeneration system has proven to be an efficient energy resource,enabling on-site generation of both electricity and hot water,substantially reducing grid *** extreme cold event resulted in significant spikes in space heating power *** optimization results demonstrate that reducing the indoor setpoint temperature effectively decreases daily power consumption by approximately 5.0%per degree *** findings help acquire better understanding of interconnections between energy efficiency and resilience of residential energy-efficient measures.

关键词： system modeling energy efficiency energy resilience cold wave thermal comfort

Strict Feasibility of Variational Inequalities in Reflexive Banach Spaces

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Acta Mathematica Sinica,English Series 2007年第3期23卷 563-570页

作者： yi ran HE Xiu Zhen MAO Mi ZHOU Department of Mathematics Sichuan Normal University Chengdu 610068 P. R. China

Strict feasibility is proved to be an equivalent characterization of （dual） variational inequalities having a nonempty bounded solution set, provided the mappings involved are stably properly quasimonotone. This generalizes an earlier result from finite-dimensional Euclidean spaces to infinitedimensional reflexive Banach spaces. Moreover, the monotonicity-type assumptions are also mildly relaxed.

关键词： variational inequalities well-positioned sets barrier cone strict feasibility stably properly quasimonotone

Evolution, resilience and causes of global petroleum gas trade networks: 1995-2020

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Petroleum Science 2024年第5期21卷 3656-3674页

作者： Na Li yi-ran Song ying Wang Chun-Bao Ge School of Economics and Management Xinjiang UniversityUrumqi830046XinjiangChina School of Business Nanjing UniversityNanjing210093JiangsuChina Hefei Advanced Research Institute Anhui University of Finance&EconomicsHefei230071AnhuiChina

Based on the HS 4-digit code trade data in UNCOMTRADE from 1995 to 2020, this paper analyzes the characteristics of the evolution of the global PG trade network using the complex network approach and analyzes the changes in its resilience at the overall and country levels, respectively. The results illustrated that:(1) The scale of the global PG trade network tends to expand, and the connection is gradually tightened, experiencing a change from a “supply-oriented” to a “supply-and-demand” pattern, in which the U.S., Russia, Qatar, and Australia have gradually replaced Canada, Japan, and Russia to become the core trade status, while OPEC countries such as Qatar, Algeria, and Kuwait mainly rely on PG exports to occupy the core of the global supply, and the trade status of other countries has been dynamically alternating and evolving.(2) The resilience of the global PG trade network is lower than that of the random network and decreases non-linearly with more disrupted countries. Moreover, the impact of the U.S. is more significant than the rest of countries. Simulations using the exponential random graph model(ERGM) model revealed that national GDP, institutional quality, common border and RTA network are the determinants of PG trade network formation, and the positive impact of the four factors not only varies significantly across regions and stages, but also increases with national network status.

关键词： Petroleum gas Complex network approach Network resilience Exponential random graph model

Characterization and Comparison Analysis of WHO Monographs on Selected Medicinal Plants and Iso Standards of Chinese Materia Medica

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Chinese Journal of Integrative Medicine 2023年第6期29卷 540-548页

作者： YANG Jing-yi SANG Zhen WANG Rui SHI Yan-hong HUANG yi-ran School of Pharmacy Shanghai University of Traditional Chinese MedicineShanghai(201203)China Institute of Traditional Chinese Medicine International Standardization Shuguang Hospital Affliated to Shanghai University of Traditional Chinese MedicineShanghai(201203)China Institute of Traditional Chinese Medicine International Standardization Shanghai University of Traditional Chinese MedicineShanghai(201203)China

Medicinal plants or Chinese materia medica(CMM)are now attracting worldwide attention as they have increasingly prominent advantages over chemical drugs in disease treatment and *** the 1990s,World Health Organization(WHO)and International Organization for Standardization established the Technical Committee of Traditional Chinese Medicine(ISO/TC 249)have carried out the development of quality standards on medicinal plants or CMMs respectively,and a considerable number of monographs and international standards have been *** the two international organizations adhere to different principles,the standards they develop naturally have different *** by market demand and international trade,ISO mainly takes quality,efficacy and safety into consideration when developing standards,while WHO pays more attention to clinical practice,quality control and medication *** to now,there is a lack of comparative analysis on the records,background,principles,basic content,and main requirements of quality standards on medicinal plants or CMMs respectively published by WHO and ***,based on international standards of CMM developed by ISO/TC 249 platform and WHO Monographs on Selected Medicinal Plants,this paper systematically compares the purposes,selected principles,standard-developing process,basic content,and main quality requirements to summarize their similarities and differences,and find their merits,aiming to serve as a reference to the development of international standards for CMMs that helps them go global.

关键词： Chinese materia medica medicinal plants international standards International Organization for Standardization Technical Committee of Traditional Chinese Medicine World Health Organization

Slowly rotating charges from Weyl double copy for Kerr black hole with Chern-Simons correction

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Communications in Theoretical Physics 2024年第8期76卷 139-146页

作者： yi-ran Liu Jing-Rui Zhang Yun-Long Zhang School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100149China National Astronomy Observatories Chinese Academy of ScienceBeijing 100101China International Center for Theoretical Physics Asia-Pacific Beijing/HangzhouChina

The Weyl double copy builds the relation between gauge theory and gravity theory, in particular the correspondence between gauge solutions and gravity solutions. In this paper, we obtain the slowly rotating charge solutions from the Weyl double copy for the Kerr black hole with small Chern-Simons correction. Based on the Weyl double copy relation, for the Petrov type D solution in Chern-Simons modified gravity, we find the additional correction to the electromagnetic field strength tensor of the rotating charge. For the Petrov type I solution, we find that the additional electromagnetic field strength tensors have external sources, while the total sources vanish at the leading order.

关键词： Chern-Simons modified gravity Weyl double copy Kerr black hole

A structural comparison of measurement-based admission control algorithms

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The Journal of China Universities of Posts and Telecommunications 2006年第3期13卷 81-86页

作者： GU yi-ran WANG Suo-ping WU Hai-ya The College of Automation Nanjing University of Posts and TelecommunicationsNanjing 210003 China Ningbo Branch Co. Zhejiang Telecommunication Co. Ltd. Zhejiang ProvinceNingbo 315000 China

Measurement-based admission control （MBAC） algorithm is designed for the relaxed real-time service. In contrast to traditional connection admission control mechanisms, the most attractive feature of MBAC algorithm is that it does not require a prior traffic model and that is very difficult for the user to come up with a tight traffic model before establishing a flow. Other advantages of MBAC include that it can achieve higher network utilization and offer quality service to users. In this article, the study of the equations in the MBAC shows that they can all be expressed in the same form. Based on the same form, some MBAC algorithms can achieve same performance only if they satisfy some conditions.

关键词： connection admission control MBAC measurement process

Synthesis of High Performance Cyclic Olefin Polymers Using Highly Efficient WCl6-based Catalyst System

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Chinese Journal of Polymer Science 2018年第2期36卷 214-221页

作者： yi-ran Zhang Ji-Xing Yang Li Pan Yue-Sheng Li Tianjin Key Laboratory of Composite and Functional Materials School of Materials Science and EngineeringTianjin UniversityTianjin 300350China Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China

Cyclic olefin polymers（COPs） with high glass transition temperature, high transparency（higher than 80%） in the visible light range, excellent thermal stability and outstanding mechanical properties have been synthesized by effective ring opening metathesis polymerization（ROMP） of exo-1,4,4 a,9,9 a,10-hexahydro-9,10（1′,2′）-benzeno-l,4-methanoanthracene（HBM） and dicyclopentadiene（DCPD） or norbornene（NBE） using WCl6/i-Bu3Al/ethanol/1-hexene catalyst system, followed by hydrogenation of double bonds. 1-Hexene acted as a molecular weight controller in the polymerization reaction, tuning the number-average molecular weight（Mn） of P-HBM from 5.8 × 10^4 to 41.1 × 10^4. The monomer composition and thermal properties of the copolymers were characterized by nuclear magnetic resonance（NMR）, differential scanning calorimetry（DSC） and thermogravimetric analysis（TGA）. The saturated polymers exhibited high decomposition temperatures（Td） around 340 ℃ and glass transition temperatures（Tg） in the range from 117.5 ℃ to 219.7 ℃. What is more, tensile tests indicated that the mechanical properties of the COPs could be effectively tuned in a wide range by introducing varying amount of small cyclic olefin such as DCPD or NBE.

关键词： Ring-opening metathesis polymerization Hydrogenation Cyclic olefin polymers Glass transition temperature Mechanical properties

Prediction of properties distribution of 7B50 alloy thick plates after quenching and aging by quench factor analysis method

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Rare Metals 2019年第11期38卷 1043-1050页

作者： Lei Kang yi-ran Zhou Gang Zhao Kun Liu Ni Tian Key Laboratory for Anisotropy and Texture of Materials Ministry of EducationSchool of Materials Science and EngineeringNortheastern UniversityShenyang 110819China Department of Applied Science University of Quebec at ChicoutimiSaguenayQC G7H 2B1Canada

In the present work,continuous cooling curves were accurately measured by the modified Jominy specimen of 7B50 alloy during water-spray quenching ***,the time-temperature-properties(TTP) curves of this alloy were obtained during isothermal *** on the accurate cooling curves and TTP curves,the hardness distribution along the thickness direction of 7B50 alloy thick plates was predicted by quench factor analysis *** is found that the quench sensitive temperature range of 7B50 alloy is 240-410℃,the nose temperature is 335℃,and the incubation period at the nose temperature is about 0.87 *** 7B50 alloy was isothermal treated at 180-400℃ after solid solution treatment(470℃ for 1 h followed by 483℃ for 2 h),the exponent(n) in the Johnson-Mehl-Avrami equation is close to 1 until transformed fraction of new precipitates is up to 60%,indicating that new precipitates first grow into rodlike shape and then coarsen or *** the distance is less than 65 mm from the spray quenching surface of the modified Jominy specimen,the deviation between the predicted and measured hardness is less than 2.7%,confirming the quench factor analysis method as the feasible way to predict the hardness distribution along the thickness direction of 7B50 alloy thick *** the distance from the spray quenching surface is 25 mm,the average cooling rate in quench sensitive temperature range is 9.93 ℃·s^-1,while the quench factor(τ) is 9.89 and the corresponding predicted hardness is HV 185.1 equivalent to 97.3% of the maximum measured hardness of 7B50 alloy in T6 temper.

关键词： 7B50 aluminum alloy Quench factor analysis method Time-temperature-properties curve Continuous cooling curve Properties prediction