检索结果-南通市图书馆

NUMERICAL METHOD FOR MULTI-BODY FLUID INTERACTION BASED ON IMMERSED BOUNDARY METHOD

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2011年第4期23卷 476-482页

作者： ming ping-jian ZHANG Wen-ping School of Power and Energy Engineering Harbin Engineering University Harbin 150001 China

A Cartesian grid based on Immersed Boundary Method （IBM）, proposed by the present authors, is extended to unstructured grids. The advantages of IBM and Body Fitted Grid （BFG） are taken to enhance the computation efficiency of the fluid structure interaction in a complex domain. There are many methods to generate the BFG, among which the unstructured grid method is the most popular. The concept of Volume Of Solid （VOS） is used to deal with the multi rigid body and fluid interaction. Each body surface is represented by a set of points which can be traced in an anti-clockwise order with the solid area on the left side of surface. An efficient Lagrange point tracking algorithm on the fixed grid is applied to search the moving boundary grid points. This method is verified by low Reynolds number flows in the range from Re = 100 to 1000 in the cavity with a moving lid. The results are in a good agreement with experimental data in literature. Finally, the flow past two moving cylinders is simulated to test the capability of the method.

关键词： fluid-structure interaction Immersed Boundary Method (IBM) Volume Of Solid (VOS) unstructured grids

NUMERICAL SIMULATION OF SLOSHING IN RECTANGULAR TANK WITH VOF BASED ON UNSTRUCTURED GRIDS

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2010年第6期22卷 856-864页

作者： ming ping-jian DUAN Wen-yang College of Power and Energy Engineering Harbin Engineering University Harbin 150001 China College of Shipbuilding Engineering Harbin Engineering University Harbin 150001 China

A new method for sloshing simulation in a sway tank is present, in which the two phase interface is treated as a physical discontinuity, which can be captured by a well-designed high order scheme. Based on Normalized Variable Diagram （NVD）, a high order discretization scheme with unstructured grids is realized, together with a numerical method for free surface flow with a fixed grid. This method is implemented in an in-house code General Transport Equation Analyzer （ GTEA ） which is an unstructured grids finite volume solver. The present method is first validated by available analytical solutions. A simulation for a 2-D rectangular tank at different excitation frequencies of the sway is carried out. A comparison with experimental data in literature and results obtained by commercial software CFX shows that the sloshing load on the monitor points agrees well with the experimental data, with the same grids, and the present method gives better results on the secondary peak. It is shown that the present method can simulate the free surface overturning and breakup phenomena.

关键词： sloshing numerical simulation unstructured grid Volume Of Fluid (VOF)

Multi-objective optimization and evaluation of supercritical CO_(2) Brayton cycle for nuclear power generation

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第2期35卷 183-209页

作者： Guo-Peng Yu Yong-Feng Cheng Na Zhang ping-jian ming Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China School of Civil Engineering and Architecture East China Jiaotong UniversityNanchang 330013China

The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle *** models of four Brayton cycle layouts are developed in this study for different reactors to reduce the cost and increase the thermohydraulic performance of nuclear power generation to promote the commercialization of nuclear *** analysis,multi-objective optimizations,and four decision-making methods are applied to obtain each Brayton scheme’s optimal thermohydraulic and economic *** show that for the same design thermal power scale of reactors,the higher the core’s exit temperature,the better the Brayton cycle’s thermo-economic *** the four-cycle layouts,the recompression cycle(RC)has the best overall performance,followed by the simple recuperation cycle(SR)and the intercooling cycle(IC),and the worst is the reheating cycle(RH).However,RH has the lowest total cost of investment(C_(tot))of$1619.85 million,and IC has the lowest levelized cost of energy(LCOE)of 0.012$/(kWh).The nuclear Brayton cycle system’s overall performance has been improved due to *** performance of the molten salt reactor combined with the intercooling cycle(MSR-IC)scheme has the greatest improvement,with the net output power(W_(net)),thermal efficiencyη_(t),and exergy efficiency(η_(e))improved by 8.58%,8.58%,and 11.21%,*** performance of the lead-cooled fast reactor combined with the simple recuperation cycle scheme was optimized to increase C_(tot) by 27.78%.In comparison,the internal rate of return(IRR)increased by only 7.8%,which is not friendly to investors with limited *** the nuclear Brayton cycle,the molten salt reactor combined with the recompression cycle scheme should receive priority,and the gas-cooled fast reactor combined with the reheating cycle scheme should be considered carefully.

关键词： Supercritical CO_(2)Brayton cycle Nuclear power generation Thermo-economic analysis Multi-objective optimization Decision-making methods

Danhongqing formula alleviates cholestatic liver fibrosis by downregulating long non-coding RNA H19 derived from cholangiocytes and inhibiting hepatic stellate cell activation

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Medicine 2024年第2期22卷 188-198页

作者： Meng Li Yang Zhou Hui Zhu Lie-ming Xu jian ping Institute of Liver Diseases Shuguang HospitalShanghai University of Traditional Chinese MedicineShanghai 201203China Preventive Treatment Center Yueyang Hospital of Integrated Traditional Chinese and Western MedicineShanghai University of Traditional Chinese MedicineShanghai 200437 China Department of Gastroenterology Suzhou Traditional Chinese Medicine HospitalSuzhou 215000Jiangsu ProvinceChina Shanghai Key Laboratory of Traditional Chinese Medicine Shanghai 201203China Key Laboratory of Liver and Kidney Diseases(Ministry of Education) Shanghai 201203China

Objective:This study explores the mechanism of action of Danhongqing formula(DHQ),a compoundbased Chinese medicine formula,in the treatment of cholestatic liver ***:In vivo experiments were conducted using 8-week-old multidrug resistance protein 2 knockout(Mdr2-/-)mice as an animal model of cholestatic liver *** was administered orally for 8 weeks,and its impact on cholestatic liver fibrosis was evaluated by assessing liver function,liver histopathology,and the expression of liver fibrosis-related ***-time polymerase chain reaction,Western blot,immunohistochemistry and other methods were used to observe the effects of DHQ on long non-coding RNA H19(H19)and signal transducer and activator of transcription 3(STAT3)phosphorylation in the liver tissue of Mdr2-/-*** addition,cholangiocytes and hepatic stellate cells(HSCs)were cultured in vitro to measure the effects of bile acids on cholangiocyte injury and H19 *** overexpressing H19 were constructed,and a conditioned medium containing H19 was collected to measure its effects on STAT3 protein expression and cell *** intervention effect of DHQ on these processes was also *** overexpressing H19 were constructed to measure the impact of H19 on cell activation and assess the intervention effect of ***:DHQ alleviated liver injury,ductular reaction,and fibrosis in Mdr2-/-mice,and inhibited H19expression,STAT3 expression and STAT3 *** formula also reduced hydrophobic bile acid-induced cholangiocyte injury and the upregulation of H19,inhibited the activation of HSCs induced by cholangiocyte-derived conditioned medium,and decreased the expression of activation markers in *** overexpression of H19 in a human HSC line confirmed that H19 promoted STAT3 phosphorylation and HSC activation,and DHQ was able to successfully inhibit these ***:DHQ effectively alleviated spontaneous cholestatic liver fibrosis in Md

关键词： Liver cirrhosis biliary Long non-coding RNA H19 Danhongqing formula Cholangiocyte Hepatic stellate cells STAT3 transcription factor

Research on thermal insulation materials properties under HTHP conditions for deep oil and gas reservoir rock ITP-Coring

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第04期21卷 2625-2637页

作者： Zhi-Qiang He He-ping Xie Ling Chen jian-ping Yang Bo Yu Zi-Jie Wei ming-Zhong Gao State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering College of Water Resource and Hydropower Sichuan University Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization Institute of Deep Earth Sciences and Green Energy College of Civil and Transportation Engineering Shenzhen University School of Mechanical Engineering Sichuan University College of Polymer Science and Engineering Sichuan University

Deep oil and gas reservoirs are under high-temperature conditions, but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability, resulting in distorted resource assessments. The development of in situ temperaturepreserved coring(ITP-Coring) technology for deep reservoir rock is urgent, and thermal insulation materials are key. Therefore, hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials) were proposed as thermal insulation materials. The materials properties under coupled hightemperature and high-pressure(HTHP) conditions were tested. The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased; additionally,increasing temperature accelerated the process. High temperatures directly caused the thermal conductivity of the materials to increase; additionally, the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity. High temperatures weakened the matrix, and high pressures destroyed the HGM, which resulted in a decrease in the tensile mechanical properties of the materials. The materials entered the high elastic state at 150.C, and the mechanical properties were weakened more obviously, while the pressure led to a significant effect when the water absorption was above 10%. Meanwhile, the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86% at 100.C and 100 MPa, respectively, which meet the application requirements of the self-designed coring device. Finally, K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100.C and 100 MPa. To further improve the materials properties, the interface layer and EP matrix should be optimized. The results can provide references for the optimization and engineering application of materials and thus technical su

关键词： Deep oil and gas reservoir rock In situ temperature-preserved coring (ITP-Coring) Hollow glass microsphere/epoxy resin thermal insulation materials (HGM/EP materials) High-temperature and high-pressure (HTHP) Physical and mechanical properties

Spherical Confinement Generates Entropic Force to Accelerate Polymer Chain Detachment

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第3期42卷 407-416,I0010页

作者： Yu-Shan Zheng jian-ping Zhou Yan Xu Kai Li Mechanical Engineering Xinjiang UniversityUrumqi 830002China

To understand the dynamic process of polymer detachment, it is necessary to determine the mean detachment time of a single breakable link, which is modeled as a spring. Normally, this time can be viewed as the escape of a Brownian particle from the potential well of the spring. However, as the free dangling length of the polymer chain increases, the conformational entropy of the chain is affected by geometric confinement. It means that the wall exerts a repulsive force on the chain, resulting in accelerated link detachment from a macroscopic perspective. In this work, we investigate the effect of entropy on the detachment rate in the case where the substrate is spherical. We demonstrate that spherical confinement accelerates chain detachment both inside and outside the sphere. An analytical expression for the mean detachment time of breakable links is given, which includes an additional pre-factor that is related to the partition function. Additionally, we analyze the expressions for entropic forces inside the sphere, outside the sphere, and on a flat wall, comparing their magnitudes to explain the difference in mean detachment time.

关键词： Polymer detachment Breakable link Entropic force Mean first passage time

Accurate simulations of pure-viscoacoustic wave propagation in tilted transversely isotropic media

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第2期21卷 866-884页

作者： Qiang Mao jian-ping Huang Xin-Ru Mu Ji-Dong Yang Yu-jian Zhang Geosciences Department China University of Petroleum(East China)Qingdao266580ShandongChina Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao266207ShandongChina

Forward modeling of seismic wave propagation is crucial for the realization of reverse time migration(RTM) and full waveform inversion(FWI) in attenuating transversely isotropic media. To describe the attenuation and anisotropy properties of subsurface media, the pure-viscoacoustic anisotropic wave equations are established for wavefield simulations, because they can provide clear and stable wavefields. However, due to the use of several approximations in deriving the wave equation and the introduction of a fractional Laplacian approximation in solving the derived equation, the wavefields simulated by the previous pure-viscoacoustic tilted transversely isotropic(TTI) wave equations has low accuracy. To accurately simulate wavefields in media with velocity anisotropy and attenuation anisotropy, we first derive a new pure-viscoacoustic TTI wave equation from the exact complex-valued dispersion formula in viscoelastic vertical transversely isotropic(VTI) media. Then, we present the hybrid finite-difference and low-rank decomposition(HFDLRD) method to accurately solve our proposed pure-viscoacoustic TTI wave equation. Theoretical analysis and numerical examples suggest that our pure-viscoacoustic TTI wave equation has higher accuracy than previous pure-viscoacoustic TTI wave equations in describing q P-wave kinematic and attenuation characteristics. Additionally, the numerical experiment in a simple two-layer model shows that the HFDLRD technique outperforms the hybrid finite-difference and pseudo-spectral(HFDPS) method in terms of accuracy of wavefield modeling.

关键词： Pure-viscoacoustic TTI wave equation Attenuation anisotropy Seismic modeling Low-rank decomposition method

Short-term displacement prediction for newly established monitoring slopes based on transfer learning

在线全文

学校读者我要写书评

暂无评论

China Geology 2024年第2期7卷 351-364页

作者： Yuan Tian Yang-landuo Deng ming-zhi Zhang Xiao Pang Rui-ping Ma jian-xue Zhang Institute of Remote Sensing and Geographical Information Systems Peking UniversityBeijing 100871China Beijing Key Laboratory of Spatial Information Integration and Its Applications Beijing 100871China Institute of Public Safety Research Department of Engineering PhysicsTsinghua UniversityBeijing 100084China China Institute of Geo-Environment Monitoring Beijing 100081China Technology Innovation Center for Geohazard Monitoring and Risk Early Warning Ministry of Natural ResourcesBeijing 100081China

This study makes a significant progress in addressing the challenges of short-term slope displacement prediction in the Universal Landslide Monitoring Program,an unprecedented disaster mitigation program in China,where lots of newly established monitoring slopes lack sufficient historical deformation data,making it difficult to extract deformation patterns and provide effective predictions which plays a crucial role in the early warning and forecasting of landslide hazards.A slope displacement prediction method based on transfer learning is therefore ***,the method transfers the deformation patterns learned from slopes with relatively rich deformation data by a pre-trained model based on a multi-slope integrated dataset to newly established monitoring slopes with limited or even no useful data,thus enabling rapid and efficient predictions for these ***,as time goes on and monitoring data accumulates,fine-tuning of the pre-trained model for individual slopes can further improve prediction accuracy,enabling continuous optimization of prediction results.A case study indicates that,after being trained on a multi-slope integrated dataset,the TCN-Transformer model can efficiently serve as a pretrained model for displacement prediction at newly established monitoring *** three-day average RMSE is significantly reduced by 34.6%compared to models trained only on individual slope data,and it also successfully predicts the majority of deformation *** fine-tuned model based on accumulated data on the target newly established monitoring slope further reduced the three-day RMSE by 37.2%,demonstrating a considerable predictive *** conclusion,taking advantage of transfer learning,the proposed slope displacement prediction method effectively utilizes the available data,which enables the rapid deployment and continual refinement of displacement predictions on newly established monitoring slopes.

关键词： Landslide Slope displacement prediction Transfer learning Integrated dataset Transformer Pre-trained model Universal Landslide Monitoring Program(ULMP) Geological hazards survey engineering

Constructing highly safe and long-life calcium ion batteries based on hydratedvanadium oxide cathodes featuring a pillar structure

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第6期43卷 2597-2612页

作者： Chun-Fang Wang Shi-Wei Zhang Lan Huang Yuan-Min Zhu Feng Liu jian-Chuan Wang Li-ming Tan Chun-Yi Zhi Cui-ping Han Powder Metallurgy Research Institute Central South UniversityChangsha410083China Songshan Lake Materials Laboratory Dongguan 523808China Research Institute of Interdisciplinary Science and School of Materials Science and Engineering Dongguan University of TechnologyDongguan 523808China Department of Materials Science and Engineering City University of Hong KongHong Kong 999077China Faculty of Materials Science and Energy Engineering/Institute of Technology for Carbon Neutrality Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

Calcium-ion batteries(CIBs)have generated intense interest due to the growing demand for safer,cheaper,and large-scale energy storage ***,their development is still in its infancy,owing to the lack of suitable cathodes for sustaining reversiblc Ca^(2+)intercalation/***,layered H_(2)V_(3)O_(8)(HVO)with Zn^(2+)pre-insertion(ZHVO)is reported as a high-rate and highly durable cathode material for *** existence of Zn^(2+)and H_(2)O pillars could expand the interlayer spacing up to 1.8 nm,which is favorable for the diffusion of bulky Ca^(2+).The formation of Zn-O bonds facilitates electron transfer and enhances electrical ***,the ZHVO cathode achieves superior capacity performance(213.9 mAh·g^(-1)at 0.2 A·g^(-1))and long lifespan(78.3%for 1,000 cycles at 5 A·g^(-1))compared to pristine *** functional theory(DFT)calculations revealed that Zn^(2+)moved during Ca^(2+)intercalation,thereby reducing the diffusion energy barrier and facilitating Ca^(2+)***,a safe aqueous calcium ion cell was successfully assembled.

关键词： Multivalent batteries Calcium-ion batteries Layered structure Vanadium oxide Cathode materials