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Unsteady magnetohydrodynamic stagnation point flow — closed-form analytical solutions

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Applied Mathematics and Mechanics(English Edition) 2019年第4期40卷 449-464页

作者： T.G.fANG f.J.wang Bo GAO Mechanical and Aerospace Engineering Department North Carolina State University School of Energy & Power Engineering Jiangsu University

This paper investigates the unsteady stagnation point flow and heat transfer of magnetohydrodynamic(MHD) fluids over a moving permeable flat surface. The unsteady Navier-Stokes(NS) equations are transformed into a similarity nonlinear ordinary differential equation, and a closed form solution is obtained for the unsteadiness parameter of 2. The boundary layer energy equation is transformed into a similarity equation,and is solved for a constant wall temperature and a time-dependent uniform wall heat flux case. The solution domain, velocity, and temperature profiles are calculated for different combinations of parameters including the Prandtl number, mass transfer parameter, wall moving parameter, and magnetic parameter. Two solution branches are obtained for certain combinations of the controlling parameters, and a stability analysis demonstrates that the lower solution branch is not stable. The present solutions provide an exact solution to the entire unsteady MHD NS equations, which can be used for validating the numerical code of computational fluid dynamics.

关键词： unsteady stagnation point flow stretching/shrinking sheet magnetohy-drodynamic(MHD) Navier-Stokes(NS)equation

Structural evolution of Al–8%Si hypoeutectic alloy by ultrasonic processing

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Journal of Materials Science & Technology 2017年第11期33卷 1235-1239页

作者： J.Y.wang B.J.wang L.f.Huang Department of Applied Physics Northwestern Polytechnical University Xi'an 710072 China

High intensity power ultrasound was respectively introduced into three different solidification stages of Al–8%Si hypoeutectic alloy, including the fully liquid state before nucleation, the nucleation and growth process of primary α（Al） phase and L →（Al）＋（Si） eutectic transformation period. It is found that both the primary α（Al） phase and（Al ＋ Si） eutectic structure were refined by different degrees with various growth morphologies depending on the ultrasonic treatment stage. Based on the experimental results,the cavitation-induced nucleation due to the high undercooling caused by the collapse of tiny cavities was proposed as the major reason for refining the primary α（Al） phase. Meanwhile, obvious eutectic morphological change was observed only when ultrasound was directly introduced in the eutectic transformation stage, in which typical divorced eutectics and（Al ＋ Si） eutectic cells with symmetrical flower shape were formed at the top of the alloy sample. The introduction of ultrasound in each solidification stage also improves the yield strength of Al–8% Si alloy to a diverse extent.

关键词： Solidification Microstructure Metals and alloys Power ultrasound Refinement

Environmental impact of radionuclide migration in groundwater from a low intermediate level radioactive waste repository

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Journal of Environmental Sciences 2001年第2期13卷 180-184页

作者： J S wang Z f Yang S S Li Z M wang Institute of Environmental Sciences Beijing Normal University State Key Joint Laboratory of Environmental Simulation and Pollution Control Beijing 100875 China.

The radionuclide migration from a certain Chinese repository with low-intermediate level radioactive solid waste is studied. The migration in groundwater is analyzed and computed in detail. Under presumption of normal releasing, or the bottom of the repository has been marinated for one month with precipitation reaching 600 mm once and a 6 m aerated zone exists, a prediction for 7 radionuclides is conducted. It shows that the aerated zone is the primary barrier for migration. The migration for radionuclides 60Co, 137Cs, 90Sr, 63Ni, etc. will be retarded in it within 500 years. The concentration of 239Pu will be decreased by amount of 6 order. Only 3H and 14C can migrate through the aerated zone. The radionuclides that go through the aerated zone and enter the aquifer will exist in spring, stream and sea. Based on this, the intake dose by residents in different age group resulting from drinking contaminated spring water, eating seafood is calculated. The results showed that the impact of the repository to the key resident group is lower than the limit in national repository regulation standard. This complies with the repository management target.

关键词： intermediate level radioactive waste repository Environmental impact of radionuclide migration in groundwater from a low

Recovery of rare and precious metals from urban mines —— A review

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frontiers of Environmental Science & Engineering 2017年第5期11卷 3-19页

作者： Mengmeng wang Quanyin Tan Joseph f. Chiang Jinhui Li Key Laboratory for Solid Waste Management and Environment Safety (Tsinghua University) Ministry of Education of China School of Environment Tsinghua University Beijing 100084 China Department of Chemistry and Biochemistry State University of New York College at Oneonta Oneonta NY 13820 USA

Urban mining is essential for continued natural resource extraction. The recovery of rare and precious metals （RPMs） from urban mines has attracted increasing attention from both academic and industrial sectors, because of the broad application and high price of RPMs, and their low content in natural ores. This study summarizes the distribution characteristics of various RPMs in urban mines, and the advantages and shortcomings of various technologies for RPM recovery from urban mines, including both conventional （pyrometallurgical, hydrometallurgical, and biometallurgical processing）, and emerging （electrochemical, supereritieal fluid, mechanochemical, and ionic liquids processing） technologies. Mechanical/physical technologies are commonly employed to separate RPMs from nonmetallic components in a pre-treatment process. A pyrometallurgical process is often used tbr RPM recovery, although the expensive equipment required has limited its use in small and medium-sized enterprises. Hydrometallurgical processing is effective and easy to operate, with high selectivity of target metals and high recovery efficiency of RPMs, compared to pyrometallurgy. Biometallurgy, though, has shown the most promise for leaching RPMs from urban mines, because of its low cost and environmental friendliness. Newly developed technologies electrochemical, supercritical fluid, ionic liquid, and mechanochemical have offered new choices and achieved some success in laboratory experiments, especially as efficient and environmentally friendly methods of recycling RPMs. With continuing advances in science and technology, more technologies will no doubt be developed in this field, and be able to contribute to the sustainability of RPM mining.

关键词： Rare and precious metals (RPMs) Distribution characteristics Recycling technology Emerging technology Supercritical fluid

Unleashing the Potential of Electroactive Hybrid Biomaterials and Self‑Powered Systems for Bone Therapeutics

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Nano-Micro Letters 2025年第2期17卷 463-497页

作者： Shichang Liu farid Manshaii Jinmiao Chen Xinfei wang Shaolei wang Junyi Yin Ming Yang Xuxu Chen Xinhua Yin Yunlei Zhou Honghui Hospital Xi’an Jiaotong UniversityXi’an 710018People’s Republic of China Department of Bioengineering Henry Samueli School of Engineering and Applied ScienceUniversity of California Los AngelesLos Angeles 90095USA Hangzhou Institute of Technology Xidian UniversityHangzhou 311231People’s Republic of China

The incidence of large bone defects caused by traumatic injury is increasing worldwide,and the tissue regeneration process requires a long recovery time due to limited self-healing *** bioelectrical phenomena have been well recognized as critical biophysical factors in bone remodeling and *** by bioelectricity,electrical stimulation has been widely considered an external intervention to induce the osteogenic lineage of cells and enhance the synthesis of the extracellular matrix,thereby accelerating bone *** ongoing advances in biomaterials and energy-harvesting techniques,electroactive biomaterials and self-powered systems have been considered biomimetic approaches to ensure functional recovery by recapitulating the natural electrophysiological microenvironment of healthy bone *** this review,we first introduce the role of bioelectricity and the endogenous electric field in bone tissue and summarize different techniques to electrically stimulate cells and ***,we highlight the latest progress in exploring electroactive hybrid biomaterials as well as self-powered systems such as triboelectric and piezoelectric-based nanogenerators and photovoltaic cell-based devices and their implementation in bone tissue ***,we emphasize the significance of simulating the target tissue’s electrophysiological microenvironment and propose the opportunities and challenges faced by electroactive hybrid biomaterials and self-powered bioelectronics for bone repair strategies.

关键词： Electroactive biomaterials Self-powered bioelectronics Bone regeneration Bone tissue

A new thermodynamically stable Nb_(2)Ni intermetallic compound phase revealed by peritectoid transition within binary Nb-Ni alloy system

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Journal of Materials Science & Technology 2022年第5期100卷 246-253页

作者： J.f.Zhao H.P.wang B.Wei School of Physical Science and Technology Northwestern Polytechnical UniversityXi’an 710072China

A new intermetallic compound of thermodynamically stable Nb_(2)Ni phase is discovered within Nb-Ni binary system,refreshing the current situation that there are only three stable intermediate phases of Nb_(7)Ni_(6),NbNi_(3) and NbNi_(8).The new stable phase is generated from the peritectoid transition:(Nb)+Nb_(7)Ni_(6)→Nb_(2)Ni,and the transformation temperature is 1533 *** refreshes the current equilibrium Nb-Ni binary phase *** is confirmed by transmission electron microscopy and the annealing experiments,which is determined to be the fCC structure(Pearson:cf96,space grope:fd-3m O2,a=11.888A).furthermore,the equilibrium properties of Nb_(2)Ni phase are produced by density functional theory,including the formation energy,cohesive energy,bulk modulus and lattice constant.

关键词： Intermetallic compound Peritectoid transition Transmission electron microscopy Density functional theory Nb alloy

No Novel Prevalent Mutations Detected in the Circulating Strains of Bf.7,BA.5.2,DY,and XBB—China,November 2022 to June 2023

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China CDC weekly 2023年第30期5卷 672-673页

作者： Liang wang George f.Gao CAS Key Laboratory of Pathogen Microbiology and Immunology Institute of MicrobiologyCenter for Influenza Research and Earlywarning(CASCIRE)CAS-TWAS Center of Excellence for Emerging Infectious Diseases(CEEID)Chinese Academy of SciencesBeijingChina University of Chinese Academy of Sciences BeijingChina.

Ongoing surveillance of severe acute respiratory syndrome virus 2(SARS-CoV-2)’s genetic variations remains crucial for effective epidemic prevention and *** prior research demonstrates the cocirculation of two pre-existing Omicron subvariants,BA.5.2 and Bf.7,which were responsible for the coronavirus disease 2019(COVID-19)surge in Beijing following modifications to prevention and control policies in mid-November 2022—a snapshot of China’s situation at the time(1).following a period of relatively low COVID-19 case count after february 2023,a noticeable increase was observed from late April 2023(2).

关键词： prevention acute respiratory

Kangfuxin solution alleviates esophageal stenosis after endoscopic submucosal dissection:A natural ingredient strategy

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World Journal of Gastroenterology 2025年第1期31卷 110-125页

作者： Xin Zhou Dan Ma Yi-Xiang He Jing Jin Hong-Lian wang Yun-feng wang fan Yang Jian-Qin Liu Jie Chen Zhi Li Department of Spleen and Stomach Diseases the Affiliated Traditional Chinese Medicine HospitalSouthwest Medical UniversityLuzhou 646000Sichuan ProvinceChina The Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Digestive System Diseases of Luzhou City The Affiliated Traditional Medicine HospitalSouthwest Medical UniversityLuzhou 646000Sichuan ProvinceChina Department of Gastroenterology Changhai HospitalNaval Medical UniversityShanghai 20082China Research Center of Integrated Chinese and Western Medicine The Affiliated Traditional Chinese Medicine HospitalSouthwest Medical UniversityLuzhou 646000Sichuan ProvinceChina School of Integrated Traditional Chinese and Western Clinical Medicine North Sichuan Medical CollegeNanchong637100Sichuan ProvinceChina

BACKGROUND Esophageal stricture ranks among the most significant complications following endoscopic submucosal dissection(ESD).Excessive fibrotic repair is a typical pathological feature leading to stenosis after *** To examine the effectiveness and underlying mechanism of Kangfuxin solution(KfX)in mitigating excessive fibrotic repair of the esophagus *** Pigs received KfX at 0.74 mL/kg/d for 21 days after esophageal full circumferential *** examinations occurred on days 7 and 21 *** vitro,recombinant transforming growth factor(TGf)-β1(5 ng/mL)induced a fibrotic microenvironment in primary esophageal fibroblasts(pEsf).After 24 hours of KfX treatment(at 1.5%,1%,and 0.5%),expression ofα-smooth muscle actin-2(ACTA2),fibronectin(fN),and type collagen I was *** signaling was analyzed,including TGf-β1,Smad2/3,and phosphor-smad2/3(p-Smad2/3).RESULTS Compared to the Control group,the groups treated with KfX and prednisolone exhibited reduced esophageal stenosis,lower weight loss rates,and improved food tolerance 21 d after *** treatment,Masson staining revealed thinner and less dense collagen fibers in the submucosal ***,the expression of fibrotic effector molecules was notably ***,KfX downregulated the transduction levels of fibrotic functional molecules such as TGf-β1,Smad2/3,and p-Smad2/*** vitro,pEsf exposed to TGf-β1-induced fibrotic microenvironment displayed increased fibrotic activity,which was reversed by KfX treatment,leading to reduced activation of ACTA2,fN,and collagen *** 1.5%KfX treatment group showed decreased expression of p-Smad 2/3 in TGf-β1-activated *** KfX showed promise as a therapeutic option for post-full circumferential esophageal ESD strictures,potentially by suppressing fibroblast fibrotic activity through modulation of the TGf-β1/Smads signaling pathway.

关键词： Kangfuxin solution Natural component Endoscopic submucosal dissection Esophagus stricture fibrosis

COVID-19 Expands Its Territories from Humans to Animals

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China CDC weekly 2021年第41期3卷 855-858页

作者： George f.Gao Liang wang Chinese Center for Disease Control and Prevention BeijingChina CAS Key Laboratory of Pathogen Microbiology and Immunology Institute of MicrobiologyCenter for Influenza Research and EarlywarningCAS-TWAS Center of Excellence for Emerging Infectious DiseasesChinese Academy of SciencesBeijingChina

THE GLOBAL STATUS Of COVID-19 PANDEMIC Since the discovery of a novel type of coronavirus named severe acute respiratory syndrome coronavirus 2(SARS-CoV-2,also known as 2019-nCoV,or HCoV-19)(1),the causative agent of coronavirus disease 2019(COVID-19),COVID-19 has been spreading globally during a short period of *** of August 17,COVID-19 had caused more than 206 million infections,of which more than 4 million had died worldwide(2),which is the worst pandemic caused by coronaviruses thus far.

关键词： acute respiratory globally