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Frontiers in Energy 2019年第3期13卷 483-493页

作者： Xiang LI Wenzheng ZHANG Zhong HUANG Dehao JU Li HUANG Mingzhi feng Xingcai LU Zhen HUANG Key Laboratory of Power Machinery and Engineering Ministry of EducationShanghai Jiao Tong UniversityShanghai 200240China Shanghai Marine Diesel Engine Research Institute Shanghai 201108China

Liquefied natural gas (LNG), mainly composed of methane, is in progress to substitute diesel fuel in heavyduty marine engine for practical, economic, and environmental considerations. However, natural gas is relatively difficult to be ignited in a large bore combustion chamber. A combustion enhancement technique called prechamber turbulent jet ignition (TJI) can permit combustion and flame propagation in a largebore volume. To investigate the effect of air-fuel equivalence ratio and pre-mixed pressure on pre-chamber TJI of methane/air mixtures with multiple orifices in a large bore volume, experimental tests and computational simulations were implemented to study the discharge of hot turbulent jets from six orifices of the pre-chamber. Different initial pressures and air-fuel equivalence ratios were considered to analyze the characteristics of TJI. The asymmetry of the turbulent jet actuated from six different orifices were found due to the asymmetric orientation of the spark plug, resulting in the inhomogeneous distribution of combustion in the constant volume chamber, which should be considered seriously in the marine engine design. Besides,as the premixed pressure increases, it has more effect on the flame propagation and plays a more important role, as it further increases.

关键词： marine engine natural gas methane turbulent jet ignition (TJI) pre-chamber

Research on numerical simulation of transient pressure for high-speed train passing through the most unfavourable length tunnel

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Transportation Safety and Environment 2023年第3期5卷 78-91页

作者： Zhao Liu feng Liu Shuanbao Yao Dawei Chen mingzhi Yang College of Mechanical Engineering Taiyuan University of TechnologyTaiyuan 030024China CRRC Qingdao Sifang Co.Ltd Qingdao 266111China Key Laboratory of Traffic Safety on Track of Ministry of Education Central South UniversityChangsha 410075China

The length of high-speed railway tunnel is an important factor affecting transient pressure of high-speed train.When the tunnel length is the most unfavourable,the transient pressure changes in the tunnel and on the surface of the train are the most severe,which may affect the safe operation of the train or damage the structure in the tunnel.Based on the three-dimensional,compressible,unsteady N-S equation and finite volume method,this paper uses the CFD numerical simulation method to study the change and amplitude distribution of the transient pressure on the train surface and the tunnel when a high-speed train passes through the most unfavourable length tunnel.A fast calculation method is proposed to save the cost of calculation;it has great applicability of pressure amplitude.The results show that the pressure distribution in the tunnel and on the surface of the train is affected by the train speed,the length of the train and the position of the measuring point.The minimum negative peak value in the tunnel appears at the position where the superposition phenomenon is the most severe,and the position will change with the speed of the train.There are two negative peak waveforms of the train surface pressure,and the first waveformn is greatly affected by the train speed.It improves a reference for studying the strength requirement of the most unfavourable length tunnels and trains,and ensures the safe operation of trains in tunnels of different lengths.

关键词： transient pressure high-speed train most unfavourable tunnel length

Profiling of miRNAs in porcine Sertoli cells

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Journal of Animal Science and Biotechnology 2021年第1期12卷 236-249页

作者： Xiaoxu Chen Yi Zheng Xueliang Li Qiang Gao Tongying feng Pengfei Zhang mingzhi Liao Xiu’e Tian Hongzhao Lu Wenxian Zeng College of Biological Science and Engineering Shaanxi University of TechnologyHanzhong 723001China Key Laboratory of Animal Genetics Breeding and Reproduction of the Ministry of AgricultureCollege of Animal Science and TechnologyNorthwest A&F UniversityYangling 712100ShaanxiChina College of Life Science Northwest A&F UniversityYangling 712100ShaanxiChina.

Background: Sertoli cells(SCs) create a specialized environment to support and dictate spermatogenesis.MicroRNAs(miRNAs), a kind of ~ 22 nt small noncoding RNAs, have been reported to be highly abundant in mouse SCs and play critical roles in spermatogenesis. However, the miRNAs of porcine SCs remain largely unknown.Methods: We isolated porcine SCs and conducted small RNA sequencing. By comparing miRNAs in germ cells, we systematically analyzed the miRNA expression pattern of porcine SCs. We screened the highly enriched SC miRNAs and predicted their functions by Gene Ontology analysis. The dual luciferase assay was used to elucidate the regulation of tumor necrosis factor receptor(TNFR)-associated factor 3(TRAF3) by ssc-miR-149.Results: The analysis showed that 18 miRNAs were highly expressed in SCs and 15 miRNAs were highly expressed in germ cells. These miRNAs were predicted to mediate SC and germ cell functions. In addition, ssc-miR-149 played critical roles in SCs by targeting TRAF3.Conclusion: Our findings provide novel insights into the miRNA expression pattern and their regulatory roles of porcine SCs.

关键词： MicroRNAs Pig Sertoli cell Spermatogenesis TRAF3

Effect of edge cracks on critical current degradation in REBCO tapes under tensile stress

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Superconductivity 2022年第1期1卷 52-62页

作者： Zhirong Yang Yi Li Peng Song mingzhi Guan feng feng Timing Qu State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Department of Mechanical Engineering Advanced Manufacturing InstituteTexas Center for SuperconductivityUniversity of HoustonHoustonTX 77024USA Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China Lab of Intelligent Manufacturing and Precision Machining Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

The slitting process for manufacturing REBa2Cu3O7δ(REBCO,RE=Rare earth)tapes of required width significantly improves the production efficiency and reduces production costs.However,edge cracks induced by the slitting process of wide REBCO tapes may cause premature degradation under high tensile stress in highfield magnets.Therefore,it is necessary to evaluate the effect of edge cracks of REBCO tapes on the critical current(Ic)degradation.Firstly,Ic degradation under artificial cracks was measured to validate the applicability of linear elastic fracture mechanics for the REBCO layer.The maximum circumferential stress criterion was used to derive the mixed-mode stress intensity factor of multiple oblique edge cracks.A semi-analytical model considering edge crack properties such as angleβ,spacing d,and length a,was built to evaluate the critical load and critical crack.We found that when the stress intensity factor at the crack tip is below KIC?2:3 MPa ffiffiffiffim p,edge cracks did not propagate.We examined commercial REBCO tapes manufactured by two different processes,concluding that edge cracks in these tapes will not cause premature degradation.

关键词： REBCO Degradation Stress intensity factor Multiple oblique edge cracks Fracture toughness

Efficient and stable PtFe alloy catalyst for electrocatalytic methanol oxidation with high resistance to CO

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Journal of Energy Chemistry 2024年第3期90卷 327-336,I0008页

作者： Qian Yang Sifan Zhang fengshun Wu Lihua Zhu Guang Li mingzhi Chen An Pei Yingliang feng Jiangxi Provincial Key Laboratory of Functional Molecular Materials Chemistry College of Chemistry and Chemical EngineeringFaculty of Materials Metallurgy and ChemistryJiangxi University of Science and TechnologyGanzhou 341000JiangxiChina College of Chemistry and Chemical Engineering Xiamen UniversityXiamen 361005FujianChina

Direct methanol fuel cells(DMFC) are widely considered to be an ideal green energy conversion device but their widespread applications are limited by the high price of the Pt-based catalysts and the instability in terms of surface CO toxicity in long-term operation.Herein,the PtFe alloy nanoparticles(NPs) with small particle size(~4.12 nm) supported on carbon black catalysts with different Pt/Fe atomic ratios(Pt_(1)Fe_(2)/C,Pt_(3)Fe_(4)/C,Pt_(1)Fe_(1)/C,and Pt_(2)Fe_(1)/C) are successfully prepared for enhanced anti-CO poisoning during methanol oxidation reaction(MOR).The optimal atomic ratio of Pt/Fe for the MOR is 1:2,and the mass activity of Pt_(1)Fe_(2)/C(5.40 A mg_(Pt)^(-1)) is 13.5 times higher than that of conventional commercial Pt/C(Pt/C-JM)(0.40 A mg_(Pt)^(-1)).The introduction of Fe into the Pt lattice forms the PtFe alloy phase,and the electron density of Pt is reduced after forming the PtFe alloy.In-situ Fourier transform infrared results indicate that the addition of oxyphilic metal Fe has reduced the adsorption of reactant molecules on Pt during the MOR.The doping of Fe atoms helps to desorb toxic intermediates and regenerate Pt active sites,promoting the cleavage of C-O bonds with good selectivity of CO_(2)(58.1%).Moreover,the Pt_(1)Fe_(2)/C catalyst exhibits higher CO tolerance,methanol electrooxidation activity,and long-term stability than other Pt_(x)Fe_(y)/C catalysts.

关键词： Alloy catalyst PtFe Methanol oxidation In-situ FTIR CO resistance

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高校大学生志愿者服务常态化机制的初步探究

中国轻工教育 2015年第3期18卷 43-45页

作者：冯明智天津科技大学天津300457

本文针对国内大学生志愿者常态化机制存在的问题,分别从信息管理机制、项目管理机制、服务培训机制、激励机制、绩效评估机制、筹资机制和共建机制提出解决措施,促进高校志愿服务事业的常态化、科学化、专业化、规范化发展,培养大学生... 详细信息

本文针对国内大学生志愿者常态化机制存在的问题,分别从信息管理机制、项目管理机制、服务培训机制、激励机制、绩效评估机制、筹资机制和共建机制提出解决措施,促进高校志愿服务事业的常态化、科学化、专业化、规范化发展,培养大学生树立正确的人生观和价值观。

关键词：大学生志愿者常态化

线间距对时速600公里级高速磁浮列车明线交会气动性能的影响

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空气动力学学报 2023年第4期41卷 31-40,I0001页

作者：王峰张雷杨明智尹小放中国中车长春轨道客车股份有限公司长春130000 中南大学交通运输工程学院长沙410075 轨道交通安全教育部重点实验室长沙410075

高速磁浮列车设计速度高达600 km/h,明线交会时压力波幅值激增,容易导致列车结构疲劳损伤。作为影响高速列车明线交会气动特性的关键参数,线间距是研究重点之一。本文采用计算流体力学数值仿真方法和网格滑移技术,模拟了高速磁浮列车在... 详细信息

高速磁浮列车设计速度高达600 km/h,明线交会时压力波幅值激增,容易导致列车结构疲劳损伤。作为影响高速列车明线交会气动特性的关键参数,线间距是研究重点之一。本文采用计算流体力学数值仿真方法和网格滑移技术,模拟了高速磁浮列车在线间距5.1 m、5.4 m、5.6 m的线路上明线交会时的气动特性,对比分析了高速磁浮列车表面压力分布及列车气动力/力矩的变化规律。结果表明:明线交会时,列车气动升力、侧向力和倾覆力矩随着线间距的增加明显降低;列车表面测点压力最大值、最小值的绝对值以及最大压力幅值随线间距增加近似呈线性关系降低;线间距5.1 m时,高速磁浮列车表面最大压力幅值为5379 Pa,小于车体承载极限±6000 Pa,满足600 km/h交会时对气动特性的要求。

关键词：高速磁浮列车线间距交会压力波压力幅值气动力

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误诊为尿布皮炎的早期先天梅毒一例

中国麻风皮肤病杂志 2022年第4期38卷 247-248页

作者：徐雅婷冯明智吴敏智苏州市第五人民医院苏州215505

患儿,男,4个月。臀部、阴囊、股部红斑1个月。曾于多家医院诊断为尿布皮炎,治疗无效。患儿TPPA阳性,TRUST 1∶512,抗梅毒螺旋体IgM阳性。患儿父母均无皮疹,TPPA均阳性,母亲TRUST滴度1∶32;父亲TRUST滴度1∶64。患儿母亲孕期未进行围产... 详细信息

患儿,男,4个月。臀部、阴囊、股部红斑1个月。曾于多家医院诊断为尿布皮炎,治疗无效。患儿TPPA阳性,TRUST 1∶512,抗梅毒螺旋体IgM阳性。患儿父母均无皮疹,TPPA均阳性,母亲TRUST滴度1∶32;父亲TRUST滴度1∶64。患儿母亲孕期未进行围产期保健,否认梅毒诊治史,分娩时医院发现母亲血梅毒抗体阳性,未对患儿进行梅毒抗体检测。早期先天性梅毒症状缺乏特异性,容易误诊,医生应予以重视,对疑似梅毒患儿行梅毒抗体检测。

关键词：先天梅毒

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船用预燃室式天然气发动机稀薄燃烧特性试验

内燃机学报 2023年第4期41卷 324-331页

作者：李翔冯明志郑圣彬黄立黄震上海交通大学动力机械与工程教育部重点实验室上海200240 上海船用柴油机研究所上海201108 船舶与海洋工程特种装备和动力系统国家工程研究中心上海200031

以船用预燃室式天然气发动机为研究对象,以点火正时(SOI)和过量空气系数(φa)为变量开展缸内稀薄燃烧特性影响规律的研究.在此基础上对试验数据开展主效应和帕累托分析,得出量化的规律性结果.结果表明:一方面,影响着火延迟和燃烧放热速... 详细信息

以船用预燃室式天然气发动机为研究对象,以点火正时(SOI)和过量空气系数(φa)为变量开展缸内稀薄燃烧特性影响规律的研究.在此基础上对试验数据开展主效应和帕累托分析,得出量化的规律性结果.结果表明:一方面,影响着火延迟和燃烧放热速率权重较大的为SOI,通过优化可以将滞燃期缩短至12°CA以内,将燃烧重心控制在14°CA ATDC以前;而对于燃烧持续期,影响权重较大的为φa,将各工况下φa控制为1.66~1.84,可以将燃烧持续期控制在28°CA以内;另一方面,φa的运行范围已经达到并超过了车用重载的稀薄极限.由于采用了独立供气的预燃室形式,船用预燃室式天然气发动机可在缸径较大、平均有效压力(BMEP)较高的前提下实现比重载天然气发动机更加稀薄的燃烧组织,从而有利于实现较高的热效率,同时更好的兼顾NO_(x)排放.

关键词：船用天然气发动机稀薄燃烧特性过量空气系数

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船舶柴油机排放控制技术的新发展

柴油机 2010年第1期32卷 13-17页

作者：冯明志七一一研究所上海201108

随着航运业和船舶制造业的迅速发展，国际上对船舶发动机排放的限制越来越严格。世界各国主要船舶柴油机制造商和研究机构都在积极致力于低排放大功率柴油机的开发研究。重点介绍了近年来船舶排放法规的变化、船舶柴油机排放控制技术的... 详细信息

随着航运业和船舶制造业的迅速发展，国际上对船舶发动机排放的限制越来越严格。世界各国主要船舶柴油机制造商和研究机构都在积极致力于低排放大功率柴油机的开发研究。重点介绍了近年来船舶排放法规的变化、船舶柴油机排放控制技术的发展趋势以及超低排放船舶柴油机研究最新进展。

关键词：船舶柴油机排放控制技术