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Journal of Magnesium and Alloys 2023年第4期11卷 1213-1223页

作者： Xuewu Li qingyuan Yu Xi Chen Qiaoxin zhang State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China School of Mechanical Engineering Xi’an University of Science and Technology58 Yanta RoadXi’an 710054China School of Mechanical and Electronic Engineering Wuhan University of Technology122 Luoshi RoadWuhan 430070China

New-type magnesium alloy with prominent solubility and mechanical property lays foundation for preparing fracturing part in petroleum extraction.Herein,Mg-xZn-Zr-SiC alloy is prepared with casting strategy.Electrochemical and compression tests are conducted to assess the feasibility as decomposable material.Morphology,composition,phase and distribution are characterized to investigate decomposition mechanism.Results indicate that floccule,substrate component and reticulate secondary phase are formed on as-prepared surface.Sample also acts out enhanced compression strength to maintain pressure and guarantee stability in dissolution process.Furthermore,as decomposition time and zinc content increase,couple corrosion intensifies,resulting in gradually enhanced decomposition rate.Rapid sample decomposition is mainly due to basal anode dissolution,micro particle exfoliation and poor decomposition resistance of corroding product.Such work shows profound significance in preparing new-type accessible alloy to ensure rapid dissolution of fracturing part and guarantee stable compression strength in oil-gas reservoir exploitation.

关键词： Magnesium alloy Corrosion dissolution Compression strength Electrochemical test Decomposition mechanism

High Order Finite Difference WENO Methods for Shallow Water Equations on Curvilinear Meshes

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Communications on Applied Mathematics and Computation 2023年第1期5卷 485-528页

作者： Zepeng Liu Yan Jiang Mengping zhang qingyuan Liu School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026AnhuiChina School of Mathematics and Physics Anhui Jianzhu UniversityHefei 230026AnhuiChina

A high order finite difference numerical scheme is developed for the shallow water equations on curvilinear meshes based on an alternative flux formulation of the weighted essentially non-oscillatory(WENO)scheme.The exact C-property is investigated,and comparison with the standard finite difference WENO scheme is made.Theoretical derivation and numerical results show that the proposed finite difference WENO scheme can maintain the exact C-property on both stationarily and dynamically generalized coordinate systems.The Harten-Lax-van Leer type flux is developed on general curvilinear meshes in two dimensions and verified on a number of benchmark problems,indicating smaller errors compared with the Lax-Friedrichs solver.In addition,we propose a positivity-preserving limiter on stationary meshes such that the scheme can preserve the non-negativity of the water height without loss of mass conservation.

关键词： Shallow water equation Well-balanced High order accuracy WENO scheme Curvilinear meshes Positivity-preserving limiter

Time-inconsistent stochastic linear quadratic control for discrete-time systems

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Science China(Information Sciences) 2017年第12期60卷 44-56页

作者： qingyuan QI Huanshui zhang School of Control Science and Engineering Shandong University

This paper is mainly concerned with the time-inconsistent stochastic linear quadratic(LQ) control problem in a more general formulation for discrete-time systems. The time-inconsistency arises from three aspects: the coefficient matrices depending on the initial pair, the terminal of the cost function involving the initial pair together with the nonlinear terms of the conditional expectation. The main contributions are: firstly,the maximum principle is derived by using variational methods, which forms a flow of forward and backward stochastic difference equations(FBSDE); secondly, in the case of the system state being one-dimensional, the equilibrium control is obtained by solving the FBSDE with feedback gain based on several nonsymmetric Riccati equations; finally, the necessary and sufficient solvability condition for the time-inconsistent LQ control problem is presented explicitly. The key techniques adopted are the maximum principle and the solution to the FBSDE developed in this paper.

关键词： time-inconsistency open-loop equilibrium control maximum principle FBSDE nonsymmetric Riccati equations

Experimental study on the flow behaviour of water-sand mixtures in fractured rock specimens

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International Journal of Mining Science and Technology 2021年第3期31卷 377-385页

作者： Boyang zhang qingyuan He Zhibin Lin Zhenhua Li School of Civil Engineering Henan Polytechnic UniversityJiaozuo 454000China State Key Laboratory of Coal Resources and Safe Mining School of MinesChina University of Mining and TechnologyXuzhou 221116China School of Minerals and Energy Resources Engineering UNSW SydneySydneyNSW 2052Australia

The study of flow behaviour of water-sand mixtures in fractured rocks is of great necessity to understand the producing mechanism and prevention of water inrush and sand gushing accidents.A self-developed seepage test system is used in this paper to conduct laboratory experiments in order to study the influence of the particle size distribution,the void ratio,and the initial mass of Aeolian sand on the flow behavior.It is concluded that the water flow velocity is insensitive to the initial mass of the Aeolian sand but increases with the power exponent in the Talbot formula and the specimen height.The outflow of the Aeolian sand increases with the power exponent in the Talbot formula,the specimen height,and the initial mass of the Aeolian sand.Besides,the outflow of the Aeolian sand changes exponentially with the water flow velocity.Finally,it is found that the fractured specimen has a maximum sand filtration capacity beyond which the outflow of the Aeolian sand significantly increases with the initial mass of the Aeolian sand.

关键词： Water inrush and sand gushing accidents Seepage flow of water-sand mixtures Fractured specimens Sand filtration capacity

Exploratory clinical study of chidamide,an oral subtype-selective histone deacetylase inhibitor,in combination with exemestane in hormone receptor-positive advanced breast cancer

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Chinese Journal of Cancer Research 2018年第6期30卷 605-612页

作者： Qingyuan Zhang Tao Wang Cuizhi Geng Yue zhang Jinwen zhang Zhiqiang Ning Zefei Jiang Department of Medical Oncology Harbin Medical University Cancer HospitalHarbin 150081China Department of Breast Cancer the 307th hospital of Chinese People's Liberation ArmyBeijing 100071China The Fourth Hospital of Hebei Medical University Shijiazhuang 050011China Shenzhen Chipscreen Biosciences Shenzhen 518057China

Objective: The recurrence or progression under endocrine therapy in hormone receptor-positive(HR+)advanced breast cancer(ABC) remained a critical clinical challenge.Chidamide is an oral subtype-selective histone deacetylase(HDAC) inhibitor with multiple functions in tumor growth inhibition and microenvironment modulation via epigenetic reprogramming.The purpose of this study was to evaluate the safety,pharmacokinetics(PK),and preliminary efficacy of chidamide in combination with exemestane in HR+ ABC patients.Methods: Eligible patients were postmenopausal women with HR+ ABC recurrent or progressed to at least one endocrine therapy.Blood samples were obtained in the run-in period and the first day of combination treatment for PK analysis.In combination treatment,patients were given exemestane 25mg daily and chidamide 30mg twice a week(BIW) until progression of disease or intolerable toxicities.A treatment cycle was defined as 4 weeks.Safety,PK parameters,and preliminary efficacy were evaluated.Results: A total of 20 patients were enrolled between July and December,2015.The median number of treatments cycle was 5.2(20.8 weeks) with 2 patients still on treatment at the data cut-off date of October,2017.The treatment-related adverse events(AE) ≥ grade 3 in more than 2 patients were neutropenia(35%),thrombocytopenia(30%),and leucopenia(20%).The plasma exposure of exemestane was consistent in the presence or absence of chidamide.A slight increase in chidamide exposure was noted in the presence of exemestane,probably due to the inter-and intra-patient variations.The best response in 16 evaluable patients was assessed by Response Evaluation Criteria in Solid Tumors(RECIST),including 4 patients with partial response,10 patients with stable disease.The median progression-free survival(PFS) was 7.6 months.Conclusions: The combination of chidamide with exemestane was generally well tolerated with promising preliminary efficacy in HR+ ABC patients.The overall results from this study encourage further pivotal trial in this pat

关键词： Advanced breast cancer hormone receptor-positive chidamide exemestane

Identification and classification of promoters using the attention mechanism based on long short-term memory

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Frontiers of Computer Science 2022年第4期16卷 103-109页

作者： Qingwen Li Lichao zhang Lei Xu Quan Zou Jin Wu qingyuan Li Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu610054China State Key Laboratory of Brain and Cognitive Science Institute of BiophysicsChinese Academy of SciencesBeijing100101China Forestry and Fruit Tree Research Institute Wuhan Academy of Agricultural SciencesWuhan430075China School of Intelligent Manufacturing and Equipment Shenzhen Institute of Information TechnologyShenzhen518172China School of Electronic and Communication Engineering Shenzhen PolytechnicShenzhen518055China School of Management Shenzhen PolytechnicShenzhen518055China

A promoter is a short region of DNA that can bind RNA polymerase and initiate gene transcription.It is usually located directly upstream of the transcription initiation site.DNA promoters have been proven to be the main cause of many human diseases,especially diabetes,cancer or Huntington’s disease.Therefore,the classification of promoters has become an interesting problem and has attracted the attention of many researchers in the field of bioinformatics.Various studies have been conducted in order to solve this problem,but their performance still needs further improvement.In this research,we segmented the DNA sequence in a k-mers manner,then trained the word vector model,inputted it into long short-term memory(LSTM)and used the attention mechanism to predict.Our method can achieve 93.45%and 90.59%cross-validation accuracy in the two layers,respectively.Our results are better than others based on the same data set,and provided some ideas for accurately predicting promoters.In addition,this research suggested that natural language processing can play a significant role in biological sequence prediction.

关键词： promoter bioinformatics natural language processing attention mechanism

Adhesive Contact of a One-Dimensional Hexagonal Quasicrystal Half-Space Punched by a Spherical Indenter

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Acta Mechanica Solida Sinica 2022年第5期35卷 787-799页

作者： Peidong Li Yuwei Liu Songhan zhang Bingmei Shao Haidong Fan qingyuan Wang Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan ProvinceSichuan UniversityChengdu610065China Chengdu University Chengdu610106China School of Civil Engineering Dalian University of TechnologyDalian116024China

This paper develops the adhesive contact theory for a one-dimensional hexagonal quasicrystal half-space punched by a spherical indenter on the basis of the classical adhesive contact models involving the Johnson–Kendall–Roberts(JKR)model,the Maugis–Dugdale(MD)model and the Derjaguin–Muller–Toporov(DMT)model.By using the superposition principle combined with the Griffith energy balance,all the significant physical quantities for adhesive contact,such as the energy release rate,indentation force,penetration depth,contact radius and pull-out force,are obtained for different models.The result for the DMT model is derived from the MD solution through a limiting procedure.A numerical calculation is carried out to verify the present analytical solutions,to compare different contact models,and to analyze the influence of the phason field on the results.It is indicated that the effect of the phason field on the result for the MD model is pronounced,especially for a small contact radius.However,the phason effect on the JKR and DMT results is not significant.The present solution can serve as a theoretical basis for nano-indentation and atomic force microscopy to measure the material properties of quasicrystals.

关键词： Adhesive contact Quasicrystal Spherical indenter Analytical solution

Long-term trend of water vapor over the Tibetan Plateau in boreal summer under global warming

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Science China Earth Sciences 2022年第4期65卷 662-674页

作者： Jingwen YU Qingquan LI Yihui DING Jie zhang qingyuan WU Xinyong SHEN Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory on Climate and Environment ChangeNanjing University of Information Science&TechnologyNanjing 210044China Laboratory for Climate Studies National Climate CenterChina Meteorological AdministrationBeijing 100081China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China

In this study,the long-term trend of water vapor over the Tibetan Plateau(TP)in boreal summer is investigated by using observation and reanalysis data from 1979 to 2019.The historical experiment simulations of 19 models that participated in the Coupled Model Intercomparison Project phase 6(CMIP6)are evaluated,and the future variation tendency under four emission scenarios is projected.The results indicate that the water vapor content and the net water vapor budget over the TP show notable increasing trends,which are mainly manifested by a significant increase in the net water vapor import and a significant decrease in the water vapor export on the eastern boundary of the TP.This is mainly due to an anomalous anticyclone from Lake Baikal to the Mongolian Plateau.The CMIP6 multi-model ensemble can well simulate the variation characteristics of the TP net water vapor budget.The projection results indicate that by the end of the twenty-first century,the water vapor content,the net water vapor import and precipitation over the TP will increase.Under a high-emissions scenario and compared with the current period(1991–2014),these three variables will increase by 47.99%,59.77%and 18.59%in the long term(2081–2100),respectively.The significant enhancement of meridional water vapor transport over the northern TP may be the main reason for the increase in humidity over the TP.

关键词： Tibetan Plateau Boreal summer Water vapor transport Long-term trend Projection

Risk factors for intracranial hemorrhage and mortality in adult patients with severe respiratory failure managed using veno-venous extracorporeal membrane oxygenation

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Chinese Medical Journal 2022年第1期135卷 36-41页

作者： Xiaojing Wu Min Li Ying Cai Tianshu Zhai Yi zhang qingyuan Zhan Sichao Gu Department of Pulmonary and Critical Care Medicine Center for Respiratory MedicineChina-Japan Friendship HospitalBeijing 100029China National Clinical Research Center for Respiratory Diseases Beijing 100029China

Background: Intracerebral hemorrhage (ICH) is one of the most severe complications during veno-venous extracorporeal membrane oxygenation (VV-ECMO). This study aimed to determine the risk factors for ICH and mortality in such patients.Methods: We analyzed the clinical data of 77 patients who received VV-ECMO due to severe respiratory failure from July 2013 to May 2019 at China-Japan Friendship Hospital. Demographical data, laboratory indices, imaging characteristics, and other clinical information were collected. Multivariable logistic regression analyses were performed to identify risk factors for ICH and mortality.Results: Of 77 patients, 11 (14.3%) suffered from ICH, and 36 (46.8%) survived. The survival rate was significantly lower (18.2% [2/11]vs. 51.5% [34/66],P = 0.040) in patients with ICH than in those without ICH. Multivariable analysis revealed that factors independently associated with ICH were diabetes mellitus (adjusted odds ratio [aOR]: 12.848, 95% confidence interval [CI]: 1.129-146.188,P = 0.040) and minimum fibrinogen during ECMO (aOR: 2.557, 95% CI: 1.244-5.252,P = 0.011). Multivariable analysis showed that factors independently associated with mortality were acute hepatic failure during ECMO (aOR: 9.205, 95% CI: 1.375-61.604,P = 0.022), CO2 retention before ECMO (aOR: 7.602, 95% CI: 1.514-38.188,P = 0.014), and minimum platelet concentration during ECMO (aOR: 0.130, 95% CI: 0.029-0.577,P = 0.007).Conclusions: Diabetes mellitus and minimum fibrinogen concentration during ECMO are risk factors for ICH in patients with severe respiratory failure managed using VV-ECMO. This indicated that anticoagulants use and nervous system monitoring should be performed more carefully in patients with diabetes when treated with VV-ECMO due to severe respiratory failure.

关键词： Veno-venous extracorporeal membrane oxygenation Severe respiratory failure Intracranial hemorrhage Mortality Risk factors

Microcrack fracturing of coal specimens under quasi-static combined compression-shear loading

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第5期12卷 1014-1026页

作者： qingyuan He Yingchun Li Danqi Li Chengguo zhang State Key Laboratory of Coal Resources and Safe Mining School of MinesChina University of Mining and TechnologyXuzhou221116China School of Minerals and Energy Resources Engineering University of New South WalesSydney2052Australia State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian116024China Department of Civil Engineering Monash UniversityClaytonMelbourneVIC3800Australia

Coal pillars are usually loaded under combined compression-shear stresses at underground coal mines.Their long-term stability is critical to the utilization of underground structures,such as underground reservoirs at coal mines.In this study,a modified rock property testing system was used to explore the mechanical properties of coal specimens under quasi-static combined compression-shear loading conditions.The acoustic emission technique was applied to investigating the microcrack fracturing of coal specimens at various inclination angles.The experimental results show that specimen inclination has remarkable effects on the microcrack initiation,microcrack damage and ultimate failure of the coal specimen.The failure mode of the coal specimen tends to transit from axial splitting to shear failure with increasing specimen inclination,and its peak strength is closely associated with the microcrack damage threshold.In practice,it is recommended to consider coal strength under combined compression-shear loading when using empirical pillar strength formulae so that the effect of pillar inclination can be included.

关键词： Microcrack initiation(CI) Microcrack damage(CD) Microcrack fracturing Acoustic emission Coal properties