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Grain refinement of 5A06 aluminum alloy welds caused by tungsten inert gas welding arc characteristics under Ar-He alternating gas supply conditions:a coupled method of water-cooled copper plate test/numerical simulation

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Journal of Iron and Steel Research International 2024年第3期31卷 767-777页

作者： Hong-bin Dai jian miao Jia-xin Lin School of Materials Science and Engineering Harbin University of Science and TechnologyHarbin 150040HeilongjiangChina

The welding arc,as a carrier for the conversion of electrical energy to thermal energy,has a direct impact on the quality of welding by its properties and *** the tungsten inert gas(TIG)welding process under the condition of Ar-He alternating gas supply,the arc is alternately converted between Ar arc and He arc with an alternating gas supply cycle,which has obvious arc change *** FLUENT software was used to numerically simulate the characteristics of the TIG arc under the condition of alternating gas supply,and the arc temperature field,arc pressure,electric potential and current density distribution under the condition of alternating gas supply were *** with the real-time data of arc pressure measured by the water-cooled copper plate with holes,it is proved that the TIG arc has obvious dynamic characteristics under the condition of Ar-He alternating gas *** unique dynamic TIG arc acts on the 5A06 aluminum alloy weld,causing the molten pool to stir,resulting in uniform microstructure and grain refinement at the weld,and thereby improving the mechanical properties of the welded joint.

关键词： Alternating gas supply Grain refinement Numerical simulation Tungsten argon arc morphology Microstructure Mechanical property

Optimal Energy-Efficient Operation of a Metro Train on a Long and Steep Downhill Segment

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CSEE Journal of Power and Energy Systems 2023年第6期9卷 2356-2365页

作者： Deqiang He Hanqing jian Yanjun Chen jian miao Zhixiao Luo Chonghui Ren Lang Zhang the department of State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Guangxi Key Laboratory of Manufacturing System&Advanced Manufacturing TechnologySchool of Mechanical EngineeringGuangxi UniversityNanning 530004China the department of Guangxi Police College Nanning 530028China. the department of Nanning Rail Transit Co. Ltd.Nanning 530029China

Because the standard four-stage operation and con-trol strategy cannot fully utilize the gravitational potential energy of a train operating on a long and steep downhill segment,this paper further improves the method for train operation and control *** improved operation includes three stages of acceleration,coasting-speed limit cruising,and *** the speed limit,time limit,and distance limit as the constraints,the coasting condition switching point,braking condition switching point,traction coefficient,and braking force coefficient are used as the decision ***,an improved train traction energy consumption model is constructed,and an improved differential evolution algorithm is designed to solve this *** improved method is used to simulate two long and steep downhill segments of the Nanning *** results show that the improved method can meet the requirements of speed limit,time limit,and distance *** with the standard four-stage operation,the improved train operation and control strategy can reduce train energy consumption by more than 40%on the two long and steep downhill segments;compared with other similar algorithms,the improved algorithm is more suitable for solving the model.

关键词： Energy-efficient operation improved differential evolution algorithm long and steep downhill segment metro train

Rearrangement and the weighted logarithmic Sobolev inequality

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Applied Mathematics(A Journal of Chinese Universities) 2021年第2期36卷 207-217页

作者： jianG Ming-hong RUAN jian-miao ZHU Xiang-rong Department of Mathematics Zhejiang Normal UniversityJinhua 321004China Department of Mathematics Zhejiang International Studies UniversityHangzhou 310014China

Here we consider some weighted logarithmic Sobolev inequalities which can be used in the theory of singular Riemanian *** give the necessary and sufficient conditions such that the 1-dimension weighted logarithmic Sob... 详细信息

关键词： rearrangement singular Riemannian manifold weighted logarithmic Sobolev inequality

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Increased CAP37 Expression in Stable Chronic Obstructive Pulmonary Disease

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Current Medical Science 2022年第5期42卷 949-957页

作者： Jin-qing CHEN Yi-fei DUAN jian-miao WANG Department of Respiratory and Critical Care Medicine Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China

Objective Cationic antimicrobial protein of 37 kDa(CAP37),a neutrophil-derived protein originally identified for its antimicrobial activity,is now known to have many regulatory effects on host ***,its role in the pathogenesis of chronic obstructive pulmonary disease(COPD)has not been *** therefore investigated the expression of CAP37 in COPD and its effects on airway structural cells,including bronchial epithelial cells,smooth muscle cells,and *** CAP37 was detected in the lung tissue,sputum,and plasma of COPD patients and the control subjects,as well as in the neutrophils stimulated by cigarette smoke extract(CSE).BEAS-2B cells,human bronchial smooth muscle cells(HBSMCs),and MRC-5 cells were treated with CAP37 or an anti-CAP37 antibody plus ***(IL)-6 and IL-8 were detected in the BEAS-2B *** cell proliferation was analyzed in the *** were also detected in the MRC-5 *** The expression of CAP37 was increased in the lung tissue and sputum supernatant of the COPD patients compared with the control *** sputum supernatant CAP37 levels were inversely correlated with the forced expiratory volume in the first second percentage predicted in ***37 was induced by CSE stimulation in the peripheral blood neutrophils from healthy ***37 induced expression of IL-6 and IL-8 in BEAS-2B cells,and collagen expression of lung fibroblasts(MRC-5 cells).However,CAP37 did not significantly alter the proliferation of the *** Our findings indicated that neutrophil-derived CAP37 may be involved in airway inflammation and fibrosis in COPD via affecting the bronchial epithelial cells,and fibroblasts,thus suggesting a possible role of CAP37 in the development and progression of COPD.

关键词： cationic antimicrobial protein of 37 kDa chronic obstructive pulmonary disease fibrosis inflammation neutrophil

On Matrix Гα-group Inverse and Гα-sharp Ordering

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Chinese Quarterly Journal of Mathematics 2008年第2期23卷 215-221页

作者： ZHANG Jin-ou CEN jian-miao Department of Mathematics Ningbo University Ningbo 315211 China

The Γα-group inverse and the Γα-sharp ordering in matrix set are introduced. Some characterizations and properties of the Γα-sharp ordering are given. The relations between the Γα-sharp ordering and the Γα-m... 详细信息

关键词： matrix Гα-group inverse Гα-sharp ordering

Calculations of plastic collapse load of pressure vessel using FEA

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第7期9卷 900-906页

作者： Peng-fei LIU Jin-yang ZHENG Li MA Cun-jian miao Lin-lin WU Institute of Chemical Machinery and Process Equipment Zhejiang University Hangzhou 310027 China

This paper proposes a theoretical method using finite element analysis(FEA) to calculate the plastic collapse loads of pressure vessels under internal pressure,and compares the analytical methods according to three criteria stated in the ASME Boiler Pressure Vessel Code. First,a finite element technique using the arc-length algorithm and the restart analysis is developed to conduct the plastic collapse analysis of vessels,which includes the material and geometry non-linear properties of vessels. Second,as the mechanical properties of vessels are assumed to be elastic-perfectly plastic,the limit load analysis is performed by em-ploying the Newton-Raphson algorithm,while the limit pressure of vessels is obtained by the twice-elastic-slope method and the tangent intersection method respectively to avoid excessive deformation. Finally,the elastic stress analysis under working pressure is conducted and the stress strength of vessels is checked by sorting the stress results. The results are compared with those obtained by experiments and other existing models. This work provides a reference for the selection of the failure criteria and the calculation of the plastic collapse load.

关键词： Plastic collapse load Pressure vessel Finite element analysis (FEA) Design by analysis (DBA)

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Quantitative Structure-Activity Relationships in the Lithium and Sodium Affinities of n-Alkyl Fluorides

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Chinese Chemical Letters 2002年第1期13卷 41-44页

作者： Ke Chun ZHANG jian miao FAN Lei LIU Qing Xiang GUO Department of Chemistry University of Science and Technology of ChinaHefei 230026

B3LYP/6-31+g (d, p) method was used to calculate the lithium and sodium affinities of n-alkyl fluoride. These affinities were found to obey the Holmes relationship, i.e. they correlate linearly with the quotient n/(n+1), where n is the number of carbon atoms in the alkyl chain. From the correlation the limiting values of lithium and sodium affinities for very long alkyl chain were predicted to be 153.3 kJ/mol and 108.4 kJ/mol, respectively.

关键词： Lithium affinity sodium affinity density functional theory C-F卪etal interaction ion attachment.

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Comparison of LAMP,GeneXpert,Mycobacterial Culture,Smear Microscopy,***,TBAg/PHA Ratio for Diagnosis of Pulmonary Tuberculosis

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Current Medical Science 2021年第5期41卷 1023-1028页

作者： Yan DENG Yi-fei DUAN Shu-pei GAO jian-miao WANG Department of Respiratory and Critical Care Medicine Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China Department of Infection Control Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China

Objective:To investigate the application value of loop-mediated isothermal amplification(LAMP),GeneXpert,mycobacterial culture,smear microscopy,***(TSPOT),ratio of TB-specific antigen to phytohemagglutinin(TBAg/PHA ratio)in the detection of mycobacterium tuberculosis in the bronchoalveolar lavage ***:A retrospective analysis was performed on the patients who underwent bronchoscopy from December 2018 to November 2019 in Tongji *** patients with positive tuberculosis culture or positive GeneXpert in bronchoalveolar lavage fluid were selected as the case group,and those without tuberculosis served as the control *** receiver operating characteristic(ROC)curve was used to evaluate the diagnostic value of LAMP,GeneXpert,culture,smear microscopy,TSPOT,and TBAg/PHA ***:For the patients with positive cultures as case,the sensitivity of LAMP,GeneXpert,smear microscopy,TSPOT and TBAg/PHA ratio was 73.49%,89.16%,25.30%,80.00%,33.85%,respectively,the specificity was 99.00%,100.00%,99.00%,86.00%,100.00%,respectively,the area under the ROC curve(AUC)was 0.849,0.938,0.633,0.830,0.669,*** the patients with positive GeneXpert as case,the sensitivity of LAMP,mycobacterial culture,smear microscopy,TSPOT and TBAg/PHA ratio was 73.20%,74.23%,22.68%,68.92%,29.73%,respectively,the specificity was 99.00%,100.00%,99.00%,86.00%,100.00%,respectively,the AUC was 0.853,0.878,0.623,0.775,0.649,***:The sensitivity of GeneXpert was *** sensitivity and diagnostic value of LAMP were slightly lower than those of GeneXpert,and were similar to tuberculosis *** sensitivity of smear microscopy was *** specificity of TSPOT was *** TBAg/PHA ratio>0.2 was used as a diagnostic index,the specificity was improved,but the sensitivity was low.

关键词： pulmonary tuberculosis bronchoalveolar lavage fluid loop-mediated isothermal amplification GeneXpert TSPOT

Diagnostic Value of Targeted Next-generation Sequencing in Pulmonary Mycobacterial Infections

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Current Medical Science 2024年第5期44卷 947-953页

作者： Yu TAO Zi-wei ZHOU Yi-fei DUAN jian-miao WANG Department of Respiratory and Critical Care Medicine Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China

Objective This study aimed to explore the diagnostic value of novel technique-targeted next-generation sequencing(tNGS)of bronchoalveolar lavage fluid(BALF)in pulmonary mycobacterial *** This retrospective study was conducted on patients who underwent bronchoscopy and tNGS,smear microscopy,and mycobacterial culture of *** with positive Mycobacterium tuberculosis(MTB)culture or GeneXpert results were classified into the tuberculosis case *** diagnosed with nontuberculous mycobacteria(NTM)-pulmonary disease(NTM-PD)composed the case group of NTM-PD *** control group comprised patients without tuberculosis or ***,specificity,and receiver operating characteristic(ROC)curves were used to evaluate the diagnostic *** For tuberculosis patients with positive mycobacterial culture results,the areas under the ROC curves(AUCs)for tNGS,GeneXpert,and smear microscopy were 0.975(95%CI:0.935,1.000),0.925(95%CI:0.859,0.991),and 0.675(95%CI:0.563,0.787),*** tuberculosis patients with positive GeneXpert results,the AUCs of tNGS,culture,and smear microscopy were 0.970(95%CI:0.931,1.000),0.850(95%CI:0.770,0.930),and 0.680(95%CI:0.579,0.781),*** NTM-PD,the AUCs of tNGS,culture,and smear-positive but GeneXpert-negative results were 0.987(95%CI:0.967,1.000),0.750(95%CI:0.622,0.878),and 0.615(95%CI:0.479,0.752),*** sensitivity and specificity of tNGS in NTM-PD patients were 100%and 97.5%,*** tNGS demonstrated superior diagnostic efficacy in mycobacterial infection,indicating its potential for clinical application.

关键词： targeted next-generation sequencing Mycobacterium tuberculosis nontuberculous mycobacteria bronchoalveolar lavage fluid