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Research on theoretical and numerical methods of single bubble oscillation

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Journal of Hydrodynamics 2021年第4期33卷 872-877页

作者： Jie-min zhan Yue-han Chen Yu-tian Li Department of Applied Mechanics and Engineering Sun Yat-sen UniversityGuangzhou510275China

A comparison of theoretical investigation and numerical simulation of a single bubble oscillation is carried out in this *** theoretical research is based on solving Rayleigh-Plesset(R-P)equation and Keller-Miksis(K-M)equation using Runge-Kutta *** numerical method focuses on the two discrete methods in the volume of fluid(VOF)method,geometric reconstruction(GR)and modified high resolution interface capturing(MHRIC).The results show that the interface captured by MHRIC in the collapse stage is more stable,and the evolution of bubble radius agrees better with the theoretical *** R-P equation and K-M equation,which omit the effect of the energy equation,have limitations when the bubble collapses under ultra-high pressure.

关键词： Cavitation bubble dynamics volume of fluid method geometric reconstruction(GR)

NUMERICAL SOLUTION OF THE NAVIER-STOKES EQUATIONS FOR 3-D REGION USING BODY-FITTED COORDINATE SYSTEM

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Journal of Hydrodynamics 1991年第3期3卷 105-109页

作者： Jie-min, zhan Di-ming, zhang Shongskan Univ Guangzhou China

A three-dimensional method is presented for the three dimensional Navier-Stokes equations using body-fitted coordinate system. For the convenience of generating the coordinate system, we give some slip-coordinate boundary conditions. Numerical results for driven flow in a polar cavity show excellent agreement with the experimental study given by L. Fuchs and N. Tillmark.

关键词： Computers Applications Fluid Mechanics Mathematical Models

A study of the effect of local scour on the flow field near the spur dike

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 98-105页

作者： Yu-Tian Li Jie-min zhan Wing-Hong Onyx Wai Department of Industrial Design School of Industrial Design and Ceramic ArtFoshan UniversityFoshan 528000China Department of Applied Mechanics and Engineering Shenzhen Campus of Sun Yat-sen UniversityShenzhen 518107China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China

The flow field near a spur dike such as down flow and horseshoe vortex system(HVS)are susceptible to the topographic changes in the local scouring process,resulting in variation of the sediment transport with *** this study,large eddy simulations with fixed-bed at different scouring stages were conducted to investigate the changes in flow *** results imply that the bed deformation leads to an increase in flow rate per unit area,which represent the capability of sediment transportation by water,in the scour ***,the intensity of turbulent kinetic energy and bimodal motion near the sand bed induced by the HVS were also ***,the peak moments between the two sediment transport mechanisms were ***,understanding the complex feedback mechanism between topography and flow field is essential for the local scour problem.

关键词： Spur dike Local scour Large eddy simulation Down flow Horseshoe vortex system

Thermodynamic reassessment of Ni–Ga binary system

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Rare Metals 2015年第12期34卷 864-872页

作者： zhan-min Cao Xian Shi Wei Xie Ikuo Ohnuma Kiyohito Ishida Zhi-Yu Qiao State Key Laboratory of Advanced Metallurgy School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Department of Materials Science Graduate School of Engineering Tohoku University

New experimental measurements of the phase diagram and the mixing enthalpy of liquid phase along with the previous experimental data were used in a reassessment of the Ni–Ga system. A set of self-consistent thermodynamic parameters of the Ni–Ga system is obtained using the calculation of phase diagram (CALPHAD) technique, and the available phase diagram and thermodynamic data are reproduced well within experimental error limits. Some noticeable improvements are obtained in the present work compared with the previous assessment: (1) the calculated Ga-rich liquidus is more reasonable; (2) Ni3Ga7 is adopted as the most Ga-rich compound rather than NiGa4; (3) the Ni5Ga3 phase is treated as the nonstoichiometric compound with consideration of its narrow homogeneity range; (4) the phase transformation between B81.5_Ni3Ga2 and Ni13Ga9 is considered instead of treating them as Ni3Ga2 phase simply; (5) the latest experimental data of mixing enthalpy for the liquid phase are adopted. The present study can be used as a basis for the development of a thermodynamic database of the Ni-based semiconductor alloy systems.

关键词： Ni–Ga system CALPHAD technique Thermodynamic reassessment Phase diagram

Subcellular distribution and chemical form of Pb in hyperaccumulator Arenaria orbiculata and response of root exudates to Pb addition

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Frontiers of Environmental Science & Engineering 2015年第2期9卷 250-258页

作者： Yanqun ZU Yuan LI Huan min Fangdong zhan Li QIN Jixiu WANG College of Resources and Environment Yunnan Agricultural University Kunming 650201 China

Solution culture was conducted in order to understand accumulation characteristics and chemical forms of Pb in Arenaria orbiculata （A. orbiculata） and the response of root exudates to Pb addition. The results showed that： 1） Pb contents in the shoot and root of A. orbiculata increased with increasing in Pb concentrations in solution. 2） The contents of Pb chemical forms under Pb addition followed as： HAc extractable fraction＇（FriAC）〉 HC1 extractable fraction （FHcl）〉 NaCl extractable fraction （FNacl）〉 ethanol-extractable fraction （FE）〉 water extractable fraction （Fw）. 3） Increased Pb level in the medium caused increases in Pb contents in the four subcellular fractions of shoots and roots, with most accumulation in FIV （Fraction ＇IV, sbluble fraction） in shoots and FI （Fraction I, cell wall fraction） in roots. 4） Contents of soluble sugar and free amino acid of root exudates increased with increasing Pb concentration in solution. Significantly positive correlations between Pb and contents of soluble sugar and free amino acid were observed. 5） With Pb concentrations in solution, low molecular weight organic acids （LMWOAs） contents followed the tendency： tartaric acid 〉 acetic acid 〉 malic acid 〉 citric acid. Significantly positive correlation was observed between Pb and citric acid contents. The results indicate that soluble sugars, free amino acid and citric acid in root exudates of *** facilitate the absorption and accumulation of Pb, which exist in NaCl-, HCI- and HAc- extractable Pb forms, FI and FIV fractions, resulting in tolerance of *** to Pb.

关键词： Pb Arenaria orbiculat'a chemical forms,subcellular distribution root exudates hydroponic c/ilture

TYPHOON PROCESS AND ITS IMPACT ON THE SURFACE CIRCULATION IN THE NORTHERN SOUTH CHINA SEA

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Journal of Hydrodynamics 2011年第1期23卷 95-104页

作者： TANG Ling zhan Jie-min CHEN Yi-zhan LI Yok-sheung NIE Yu-hua Department of Applied Mechanics and Engineering Sun Yat-sen University Guangzhou 510275 China Department of Civil and Structural Engineering The Hong Kong Polytechnic University Hong Kong China South China Sea Branch State Oceanic Administration Guangzhou 510300 China

A severe typhoon Utor,occurring between July 3 and 8,2001,brought heavy rainfall,strong wind and storm *** was responsible for tremendous destruction and economic losses in Philippines,Taiwan and *** air-sea model system （MM5 and Princeton Ocean Model（POM））was built to simulate meteorological dynamics and ocean circulation in the South China Sea（SCS）.In the POM the output of MM5 was used as the input *** an increased number of vertical levels,a high-resolution planetary boundary layer scheme and updated landuse/vegetation data,the accuracy of computing wind,temperature and other meteorological fields are improved in near surface and upper levels in MM5 *** simulated trajectory and wind speed of Utor are close to the observed *** simulated distribution of rainfall is accorded well with measured data in the Pearl River Delta（PRD）*** different meteorological stations in Hong Kong,the wind,temperature and sea surface pressure are well *** simulated ocean surface current and surface temperature fields have an obvious rightward-biased response to the typhoon Utor,and the maximum velocity and the lowest temperature region appear in the 30 km of the right side of the typhoon *** typhoon Utor could make the water 50m under the surface ocean unwell to surface and the ocean surface temperature decrease by about 2°C.

关键词： mesoscale model MM5 Princeton Ocean Model(POM) air-sea coupling ocean surface circulation

A New Property of Conjugated Polymer PFP: Catalytic Degradation of Methylene Blue Aqueous Solution

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Chinese Chemical Letters 2005年第10期16卷 1361-1363页

作者： Bi Tao SU Shi Xiong SHE Shi Xiong min zhan Ying MA Key Lab of Gansu Polymer Materials Department of Chemistry Northwest Normal University Lanzhou 730070

A new property of conjugated polymer poly（furancarbinol-co-phenol）（PFP） was studied. The target copolymer was used as a catalyst after proper heating treatment. And dye methylene blue （MB） could be fully degraded and largely mineralized on PFP, under natural light or even in dark, in a few minutes. Furthermore, the catalytic activity could be preserved after several runs and the catalyst was readily separated. The effect of calcination temperature was also observed.

关键词： PFP catalytic property MB degradation mineralization.

Changes in lake area and water level in response to hydroclimate variations in the source area of the Yellow River:a case study from Lake Ngoring

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Frontiers of Earth Science 2023年第4期17卷 920-932页

作者： Yang PU min zhan Xiaohua SHAO Josef PWERNE Philip AMEYERS Jiaojiao YAO Da ZHI School of Geographical Sciences Nanjing University of Information Science&TechnologyNanjing 210044China Department of Geology and Environmental Science University of PittsburghPittsburgh PA 15260USA Department of Earth and Environmental Sciences The University of MichiganAnn Arbor MI 48109USA

In the north-eastern Qinghai-Tibet Plateau(QTP),the source area of the Yellow River(SAYR)has been experiencing significant changes in climatic and environmental conditions in recent *** date,few studies have combined modern hydrological conditions with paleoclimate records to explore the mechanism(s)of these *** study seeks to improve understanding of hydrological variability on decadal and centennial timescales in the SAYR and to identify its general *** first determined annual fluctuations in the surface area of Lake Ngoring from 1985 to 2020 using multi-temporal Landsat *** results show that lake surface area changes were generally consistent with variations in precipitation,streamflow and the regional dry-wet index in the SAYR,suggesting that the water balance of the Lake Ngoring area is closely associated with regional hydroclimate *** records are also comparable to the stalagmite δ^(18)O monsoon record,as well fluctuations in the Southern Oscillation Index(SOI).Moreover,an association of high TSI(total solar insolation)anomalies and sunspot numbers with the expansion of Lake Ngoring surface area is observed,implying that solar activity is the key driving factor for hydrologic variability in the SAYR on a decadal *** this line of reasoning,we compared the δ^(13)C org-based lake level fluctuations of Lake Ngoring for the last millennium,as previously reported,with the hydroclimatic history and the reconstructed TSI *** conclude that the hydrological regime of Lake Ngoring has been mainly controlled by centennial fluctuations in precipitation for the last millennium,which is also dominated by solar *** general,it appears that solar activity has exerted a dominant influence on the hydrological regime of the SAYR on both decadal and centennial timescales,which is clearly manifested in the variations of lake area and water level of Lake Ngoring.

关键词： Qinghai-Tibet Plateau(QTP) source area of the Yellow River(SAYR) lake area/level Asian summer monsoon(ASM) El Nino-Southern Oscillation(ENSO) total solar insolation(TSI)

Nonalcoholic fatty liver disease is associated with benign gastrointestinal disorders

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World Journal of Gastroenterology 2013年第45期19卷 8301-8311页

作者： Srinevas K Reddy min zhan H Richard Alexander Samer S El-Kamary Department of Surgery University of Maryland School of Medicine BaltimoreMD 21201 United States Department of Epidemiology and Public Health University of Maryland School of Medicine Baltimore MD 21201United States Departments of Pediatrics Epidemiology and Public Health University of Maryland School of MedicineBaltimore MD 21201 United States

AIM:To explore associations between nonalcoholic fatty liver disease(NAFLD)and benign gastrointestinal and pancreato-biliary ***:Patient demographics,diagnoses,and hospital outcomes from the 2010 Nationwide Inpatient Sample were *** liver diseases were identified using International Classification of Diseases,the 9thRevision,Clinical Modification *** with NAFLD were compared to those with other chronic liver diseases for the endpoints of total hospital charges,disease severity,and hospital *** stepwise logistic regression analyses to assess for the independent association of demographic,comorbidity,and diagnosis variables with the event of NAFLD(vs other chronic liver diseases)were also ***:Of 7800441 discharge records,32347(0.4%)and 271049(3.5%)included diagnoses of NAFLD and other chronic liver diseases,*** patients were younger(average 52.3 years vs55.3 years),more often female(58.8%vs 41.6%),less often black(9.6%vs 18.6%),and were from higher income areas(23.7%vs 17.7%)compared to counterparts with other chronic liver diseases(all P<0.0001).Diabetes mellitus(43.4%vs 28.9%),hypertension(56.9%vs 47.6%),morbid obesity(36.9%vs 8.0%),dyslipidemia(37.9%vs 15.6%),and the metabolic syndrome(28.75%vs 8.8%)were all more common among NAFLD patients(all P<0.0001).The average total hospital charge($39607 vs$51665),disease severity scores,and intra-hospital mortality(0.9%vs6.0%)were lower among NALFD patients compared to those with other chronic liver diseases(all P<0.0001).Compared with other chronic liver diseases,NAFLD was significantly associated with diverticular disorders[OR=4.26(3.89-4.67)],inflammatory bowel diseases[OR=3.64(3.10-4.28)],gallstone related diseases[OR=3.59(3.40-3.79)],and benign pancreatitis[OR=2.95(2.79-3.12)]on multivariable logistic regression(all P<0.0001)when the latter disorders were the principal diagnoses on hospital *** relationships were observ

关键词： Nationwide inpatient sample Nonalcoholic fatty liver disease Chronic liver disease Diverticular disease Pancreatitis Gallstones Inflammatory bowel disease