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Discrete Morse Flow for Yamabe Type Heat Flows

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Journal of Partial Differential Equations 2023年第1期36卷 48-57页

作者： MA li zheng wei School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China

In this paper,we study the discrete Morse flow for either Yamabe type heat flow or nonlinear heat flow on a bounded regular domain in the whole space.We show that under suitable assumptions on the initial data g one has a weak approxi-mate discrete Morse flow for the Yamabe type heat flow on any time interval.This phenomenon is very different from the smooth Yamabe flow,where the finite time blow up may exist.

关键词： Discrete Morse flow Yamabe type flow critical exponent nonlinear heat flow

Facile fabrication of Fe/Zr binary MOFs for arsenic removal in water:High capacity,fast kinetics and good reusability

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Journal of Environmental Sciences 2023年第6期128卷 213-223页

作者： Qi Guo Yuan li Li-Wei Zheng Xiao-Yangwei Yan Xu Yi-Wen Shen Ke-Gang Zhang Chun-Gang Yuan Hebei Key Lab of Power Plant Flue Gas Multi-Pollutants Control Department of Environmental Science&EngineeringNorth China Electric Power UniversityBaoding 071000China Wetland Research Center for Baiyangdian Lake North China Electric Power UniversityBaoding 071000China

A water-stable bimetallic Fe/Zrmetal-organic framework[UiO-66(Fe/Zr)]for exceptional decontamination of arsenic in water was fabricated through a facile one-step strategy.The batch adsorption experiments revealed the excellent performances with ultrafast adsorption kinetics due to the synergistic effects of two functional centers and large surface area(498.33 m^(2)/g).The absorption capacity of UiO-66(Fe/Zr)for arsenate[As(V)]and arsenite[As(III)]reached as high as 204.1 mg/g and 101.7 mg/g,respectively.Langmuir model was suitable to describe the adsorption behaviors of arsenic on UiO-66(Fe/Zr).The fast kinetics(adsorption equilibrium in 30min,10mg/L As)and pseudo-second-ordermodel implied the strong chemisorption between arsenic ions and UiO-66(Fe/Zr),which was further confirmed by DFT theoretical calculations.The results of FT-IR,XPS analysis and TCLP test demonstrated that arsenic was immobilized on the surface of UiO-66(Fe/Zr)through Fe/Zr-O-As bonds,and the leaching rates of the adsorbed As(III)and As(V)from the spent adsorbent were only 5.6%and 1.4%,respectively.UiO-66(Fe/Zr)can be regenerated for five cycles without obvious removal efficiency decrease.The original arsenic(1.0mg/L)in lake and tapwater was effectively removed in 2.0 hr[99.0%of As(III)and 99.8%of As(V)].The bimetallic UiO-66(Fe/Zr)has great potentials in water deep purification of arsenic with fast kinetics and high capacity.

关键词： Arsenic Removal Metal-organic frameworks Bimetallic

Emerging roles of Aurora-A kinase in cancer therapy resistance

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药学学报:英文版 2023年第7期13卷 2826-2843页

作者： Dayong zheng Jun li Han Yan Gang Zhang wei li Edward Chu Ning wei School of Pharmacy North China University of Science and TechnologyTangshan 063210China Basic Medical Science College Liaoning University of Traditional Chinese MedicineShenyang 110032China Division of Biology and Biological Engineering California Institute of TechnologyPasadenaCA 91125USA Department of Oncology and Cancer Therapeutics Program Montefiore Einstein Cancer CenterAlbert Einstein College of MedicineBronxNY 10461USA

Aurora kinase A(Aurora-A),a serine/threonine kinase,plays a pivotal role in various cellular processes,including mitotic entry,centrosome maturation and spindle formation.Overexpression or gene-amplification/mutation of Aurora-A kinase occurs in different types of cancer,including lung cancer,colorectal cancer,and breast cancer.Alteration of Aurora-A impacts multiple cancer hallmarks,especially,immortalization,energy metabolism,immune escape and cell death resistance which are involved in cancer progression and resistance.This review highlights the most recent advances in the oncogenic roles and related multiple cancer hallmarks of Aurora-A kinase-driving cancer therapy resistance,including chemoresistance(taxanes,cisplatin,cyclophosphamide),targeted therapy resistance(osimertinib,imatinib,sorafenib,etc.),endocrine therapy resistance(tamoxifen,fulvestrant) and radioresistance.Specifically,the mechanisms of Aurora-A kinase promote acquired resistance through modulating DNA damage repair,feedback activation bypass pathways,resistance to apoptosis,necroptosis and autophagy,metastasis,and stemness.Noticeably,our review also summarizes the promising synthetic lethality strategy for Aurora-A inhibitors in RB1,ARID1A and MYC gene mutation tumors,and potential synergistic strategy for m TOR,PAK1,MDM2,MEK inhibitors or PD-L1 antibodies combined with targeting Aurora-A kinase.In addition,we discuss the design and development of the novel class of Aurora-A inhibitors in precision medicine for cancer treatment.

关键词： Aurora-A Therapy resistance Chemoresistance Targeted therapy Radioresistance Synthetic lethality Alisertib PROTAC

Diverse strategic approaches en route to Taxol total synthesis

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Chinese Chemical Letters 2022年第12期33卷 4957-4968页

作者： Zexian li Jianfeng zheng wei-Dong Z.li Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs School of Life Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Taxol is one of the most famous diterpenoid natural products used in clinical cancer therapy.Taxol and its analogues are popular synthetic targets and have attracted worldwide attention over the past decades.Tremendous research efforts have already been made and ten groups have achieved the total synthesis of Taxol since 1994.This mini-review summarized the recent highlights of divergent strategic approaches towards the chemical synthesis of Taxol's carbocyclic framework bearing a bridged eight-membered ring.

关键词： Taxol Total synthesis Biomimetic synthesis linear strategy Convergent strategy

Impact of Antimicrobial Stewardship Programs on Antibiotic Use and Drug Resistance:Analysis of Data from Maternal and Child Health Care Hospitals in Hubei Province,China

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Current Medical Science 2022年第5期42卷 1106-1110页

作者： Ya-zheng ZHAO Ting-ting li wei FU Department of Pharmacy Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China

ObjectiveTo evaluate the impact of Antimicrobial Stewardship Programs(ASPs)on antibiotic use and drug resistance.MethodsThis was a retrospective,multicenter,management intervention study.The data from 85 maternity hospitals(maternal and child health care hospitals)in Hubei province from 2012 to 2019 were collected.The indicators related to antimicrobial drug use included the utilization rate of different grades of antimicrobial drugs,the intensity of antimicrobial agent use,the rational use of prophylactic antimicrobial agents before class I surgical incision,and pathogenic detection and consultation rates before antimicrobial drug use.ResultsSince the implementation,the purchase of antimicrobial agents in hospitals has been maintained within the prescribed range,and the defined daily dose system(DDDs)of antimicrobial agents has been reduced,prophylactic use and accurate treatment of antimicrobial agents related to class I surgical incision have been more reasonable.With the implementation of ASPs,the detection rate of imipenem-resistant Acinetobacter baumannii,cefotaxime-resistant Escherichia coli,and methicillin-resistant Staphylococcus aureus has been decreased in China from national bacterial resistance surveillance data.ConclusionASPs have positive effects on antibiotic use and drug resistance in 85 maternity hospitals(maternal and child health care hospitals).

关键词： Antimicrobial Stewardship Program antimicrobial resistance maternal and child health care hospitals

Superplastic Tension Behavior of Dissimilar TC4/SP700 Laminate through Diffusion Bonding

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 353-363页

作者： Qianwen Zhang Tianle li Yanbin Han wei zheng Xifeng li Jianjun Wu School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an710072China AVIC Xi’an Aircraft Industry Group Company Ltd Xi’an710089China Institute of Forming Technology and Equipment School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200030China

Superplastic forming is a practical method to manufacture complex-shaped parts of titanium alloys with large deformation.Laminated parts of dissimilar titanium alloys fabricated by superplastic forming can achieve excellent performance by combining the advantages of components.This work displays the superplastic tension behavior and microstructural evolution of dissimilar TC4/SP700 laminate prepared by the diffusion bonding process.Two titanium alloys can achieve metallurgical bonding at parameters of 800℃/1 h/5 MPa.Except for dynamic recrystallization and grain growth behaviors upon superplastic tension,stress-induced phase transformation plays an important role inαtoβphase transformation apart from the elevated temperature.The superplastic deformation can be attributed to the grain boundary sliding accommodated multiplex motion of dislocations.In addition,the retained strengths of all dissimilar TC4/SP700 laminates after superplastic deformation with different strain rates and temperatures range from 807 to 890 MPa.

关键词： TC4/SP700 laminate Diffusion bonding Microstructure Superplastic tension Strength

Steady-state Voltage Security-constrained Optimal Frequency Control for Weak HVDC Sending-end AC Power Systems

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JOURNAL OF MODERN POWER SYSTEMS AND CLEAN ENERGY 2024年第2期12卷 658-669页

作者： Wang, Qiangqiang Yao, liangzhong Xu, Jian zheng, Yuping li, wei Wang, wei Wuhan Univ Sch Elect Engn & Automat Wuhan 430072 Peoples R China Wuhan Univ Hubei Engn & Technol Res Ctr AC DC Intelligent Dis Wuhan 430072 Peoples R China NARI Grp Corp State Grid Elect Power Res Inst State Key Lab Smart Grid Protect & Control Nanjing 211106 Peoples R China

Due to the fact that a high share of renewable energy sources (RESs) are connected to high-voltage direct current (HVDC) sending-end AC power systems, the voltage and frequency regulation capabilities of HVDC sending-end AC power systems have diminished. This has resulted in potential system operating problems such as overvoltage and overfrequency, which occur simultaneously when block faults exist in the HVDC link. In this study, a steady-state voltage security-constrained optimal frequency control method for weak HVDC sending-end AC power systems is proposed. The integrated virtual inertia control of RESs is employed for system frequency regulation. Additional dynamic reactive power compensation devices are utilized to control the voltage of all nodes meet voltage security constraints. Then, an optimization model that simultaneously considers the frequency and steady-state voltage security constraints for weak HVDC sending-end AC power systems is established. The optimal control scheme with the minimum total cost of generation tripping and additional dynamic reactive power compensation required is obtained through the optimization solution. Simulations are conducted on a modified IEEE 9-bus test system and practical Qing-Yu line commutated converter based HVDC (LCC-HVDC) sending-end AC power system to verify the effectiveness of the proposed method.

关键词： HVDC transmission Voltage control Reactive power Steady-state Power system stability Frequency control Power system dynamics Renewable energy source (RES) high-voltage direct current (HVDC) AC power system optimal frequency control steady-state voltage security dynamic reactive power compensation OPTIMIZATION STRATEGY STABIliTY GRIDS DFIG

Study on influence of key blasthole parameters on tunnel overbreak

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Underground Space 2023年第2期9卷 76-90页

作者： Zi-qiang li zheng li wei-wei Huang Xuan-ming Ding Hang Zhang School of Civil Engineering and Architecture Chongqing University of Science&TechnologyChongqing 401331China Key Laboratory of New Technology for Construction of Cities in Mountain Area Ministry of EducationChongqing UniversityChongqing 400045China Chongqing City Construction Investment(Group)Co. Ltd.Chongqing 400023China School of Civil Engineering Chongqing University400045China

To determine the influence of key blasthole parameters on tunnel overbreak during blasting construction,an intelligent detection sys-tem for tunnel blasting construction is independently developed.And the key blasthole parameters and overbreak of a typical section of a single line tunnel under the condition of Class V surrounding rock are analyzed and detected.The actual data obtained is compared with the results of numerical simulations and theoretical calculations.The results are as follows:(1)Quantitative analysis is performed based on the blasthole angle,opening position,and charge mass by the self-developed intelligent detection equipment for blasthole parameters,which can be used to guide the drilling construction.Intelligent scanning equipment for outline excavation can be used to image the actual excavation section in real-time and has the advantages of high precision and fast speed;(2)Tunnel overbreak can be regarded as consisting of two parts:the surrounding rock damage caused by the blasting load,and the collapse of the surrounding rock caused by the blasthole opening position.Every parameter of the peripheral hole will affect the tunnel overbreak;however,the key parameter is the blasthole opening position;(3)The distributions of the tunnel overbreak volume obtained with the theoretical analysis,finite element simulation,and measurements are basically consistent.Under the condition of Class V surrounding rock,the overbreak of this single line tunnel can reach 14.1–78.2 cm.To meet the specification requirements,the opening position and construction accuracy of the peripheral hole should be strictly controlled.

关键词： Tunnel blasting Blasthole parameters Tunnel overbreak Surrounding rock damage Smooth surface blasting

Oxidation behaviors of TA15 titanium alloy and TiBw reinforced TA15 matrix composites prepared by spark plasma sintering

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Journal of Materials Science & Technology 2020年第2期37卷 46-54页

作者： Dongjun Wang Hao li wei zheng National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Xi’an Space Engine Company limited Xi’an710100China

The purpose of this study is to investigate the oxidation behaviors of the TA15 titanium alloy and TiBw/TA15 composite with network microstructure in the temperature range of 873–1073 K.The results show that the oxidation kinetics of the TA15 titanium alloy and TiBw/TA15 composite follows different laws at various oxidation temperatures.Moreover,the effective activation energy Q for oxidation of the TA15 titanium alloy and TiBw/TA15 composite is determined to be 299±19.9 kJ/mol and 339±8.31 kJ/mol at the temperature of 973–1073 K,respectively.The experimental achievements of oxidation kinetics and oxide scales formed in the test temperatures indicate that the TiBw/TA15 composite exhibits a higher oxidation resistance than TA15 titanium alloy.A schematic diagram of oxidation mechanism is established to further reveal the oxidation process for TiBw/TA15 composite at elevated temperatures.

关键词： Composite materials Powder metallurgy Sintering Kinetics Oxidation