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CFRP厚度激光超声脉冲反射测试及工艺优化

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机械设计与制造 2024年第7期 46-49页

作者：贾红宾张明新乡职业技术学院信息工程学院河南新乡453000 河南理工大学机械工程学院河南郑州450000

为了提高碳纤维复合材料CFRP的厚度测试精度,设计了一种基于激光超声脉冲反射法的CFRP厚度测试方法,并进行工艺参数优化。研究结果表明:以凸透镜进行厚度测试时,可以达到5.2%以内的相对误差。提高光斑外径后,形成了更低幅值的超声波信... 详细信息

为了提高碳纤维复合材料CFRP的厚度测试精度,设计了一种基于激光超声脉冲反射法的CFRP厚度测试方法,并进行工艺参数优化。研究结果表明:以凸透镜进行厚度测试时,可以达到5.2%以内的相对误差。提高光斑外径后,形成了更低幅值的超声波信号。凸透镜聚焦形成的光斑面积比柱面透镜聚集形成的光斑面积更小,提高了能量密度,促进了更大幅值超声信号被激发,显著增强激光热弹效果。不存在外部光源的情况下,形成了具有稳定频率的反射信号。当光源功率提高后,信号中产生了更大噪声频率与幅值;背景噪声对多次反射回波也造成了淹没。功率0.45mW与0.60mW时,信号相对有效信号频率更大,对反射信号也造成明显影响。该研究可以拓宽到其它微观材料的厚度检测领域,具有很好的精度控制标准。

关键词：碳纤维复合材料激光超声脉冲测厚透镜光斑直径

乡村振兴战略下农村社区教育发展的价值、挑战及路径

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成人教育 2024年第6期44卷 20-26页

作者：彭海虹贾红彬张永上海开放大学社区教育部上海200433 华东师范大学教育学部上海200062

在全面推进乡村振兴的背景下,农村社区教育可以提升村民素质,赋能乡村产业、人才、文化、生态、组织振兴,建设富裕乡村、学习乡村、文明乡村、美丽乡村、善治乡村。针对当前农村社区教育在观念认识、内涵发展和体系建设等方面所面临的... 详细信息

在全面推进乡村振兴的背景下,农村社区教育可以提升村民素质,赋能乡村产业、人才、文化、生态、组织振兴,建设富裕乡村、学习乡村、文明乡村、美丽乡村、善治乡村。针对当前农村社区教育在观念认识、内涵发展和体系建设等方面所面临的多重性挑战,对标乡村振兴的战略要求,从凝聚组织发动合力、增强内涵发展活力、夯实体系建设能力等方面,尝试提出推进农村社区教育的可行性路径,为促进农村社区教育均衡普惠、特色高效发展提供借鉴。

关键词：乡村振兴农村社区教育价值挑战路径

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美沙酮按需转换法治疗癌痛的临床研究

中国疼痛医学杂志 2024年第3期30卷 189-195页

作者：杜美慧刘越曾永芬陈浩飞贾宏彬金毅徐州医科大学麻醉学院徐州221004 南京大学医学院附属金陵医院疼痛科南京210002

目的:探讨美沙酮按需转换法(Ad libitum,AL)治疗癌痛的有效性和安全性。方法:选取南京大学医学院附属金陵医院疼痛科2022年11月至2023年9月全身大剂量使用阿片类药物疼痛控制不佳的癌痛病人31例,采用每次20 mg(间隔≥2 h)按需口服美沙... 详细信息

目的:探讨美沙酮按需转换法(Ad libitum,AL)治疗癌痛的有效性和安全性。方法:选取南京大学医学院附属金陵医院疼痛科2022年11月至2023年9月全身大剂量使用阿片类药物疼痛控制不佳的癌痛病人31例,采用每次20 mg(间隔≥2 h)按需口服美沙酮转换,观察并记录美沙酮转换前、转换第1~7天和第14天病人平均疼痛数字分级评分法(numerical rating scale,NRS)评分;记录转换前、转换第1天、第3天及第7天不良反应;转换第1天至第5天补救次数;评估转换前和转换第7、14天病人生活质量(quality of life,QOL);评价并计算病人满意度和转换成功率(NRS评分降低50%,且无不能耐受的不良反应)。结果:与转换前相比,转换第1~7天及第14天病人平均NRS评分均降低(P<0.05),生活质量明显改善(P<0.001)。补救次数随滴定时间的延长而降低。病人均未出现不能耐受的药物不良反应,总体满意度为4.0(1.0),美沙酮转换成功率为93.5%。结论:全身大剂量阿片类药物使用病人,采用每次20 mg口服美沙酮按需转换效果确切、不良反应少,病人生活质量获得改善且满意度高,适合中国人群,可供临床参考。

关键词：美沙酮按需转换法癌痛

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

Extending Structures for Gel'fand-Dorfman Bialgebras

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Acta Mathematica Sinica,English Series 2024年第2期40卷 619-638页

作者： jia jia WEN Yan Yong hong School of Mathematics Hangzhou Normal UniversityHangzhou 311121P.R.China

Gel'fand-Dorfman bialgebra,which is both a Lie algebra and a Novikov algebra with some compatibility condition,appeared in the study of Hamiltonian pairs in completely integrable *** also emerged in the description of a class special Lie conformal algebras called quadratic Lie conformal *** this paper,we investigate the extending structures problem for Gel'fand-Dorfman bialgebras,which is equivalent to some extending structures problem of quadratic Lie conformal ***,given a Gel'fand-Dorfman bialgebra(A,o,[.,.]),this problem is how to describe and classify all Gel'fand-Dorfman bialgebra structures on a vector space E(A⊂E)such that(A,o,[.,.])is a subalgebra of E up to an isomorphism whose restriction on A is the identity *** by the theories of extending structures for Lie algebras and Novikov algebras,we construct an object gH2(V,A)to answer the extending structures problem by introducing the notion of a unified product for Gel'fand-Dorfman bialgebras,where V is a complement of A in *** particular,we investigate the special case when dim(V)=1 in detail.

关键词： Gel'fand-Dorfman bialgebra Lie conformal algebra Extending structures problem Novikovalgebra

Interfacial reaction between AZ91D magnesium alloy melt and mild steel under high temperature

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China Foundry 2024年第2期21卷 159-167页

作者： jia-hong Dai jian-yue Zhang bin jiang Xiang-jun Xu Zhong-tao jiang hong-mei Xie Qing-shan Yang Guo-qing Zhang College of Materials Science and Engineering Yangtze Normal UniversityChongqing 408100China National Engineering Research Center for Magnesium Alloys College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Chongqing Jiulongyuan High-tech Industry Group Co. Ltd.Chongqing 400080China Loncin Industry Co. Ltd.Chongqing 400080China Department of Materials Science and Engineering The Ohio State UniversityColumbusOH 43210USA Chongqing Key Laboratory of Materials Surface&Interface Science Chongqing University of Arts and SciencesChongqing 402160China School of Metallurgy and Material Engineering Chongqing University of Science and TechnologyChongqing 401331China

The metallurgical quality control of magnesium(Mg)and Mg alloys in melting process is required to ensure a satisfied mechanical and corrosion performance,while the typical used steel crucible introduces impurities and interfacial interaction during melting ***,a systematic study about impurities diffusion and interfacial interaction between molten Mg and steel is *** the present study,the interfacial reaction between molten AZ91D Mg alloy and mild steel during melting process was investigated with the melting temperatures of 700℃,750℃ and 800℃.The results show that Al(Fe,Mn)intermetallic layer is the intermetallic primarily formed at the interfaces of AZ91D melt and mild ***,Al_(8)(Mn,Fe)5is indexed between Al(Fe,Mn)and ***_(3)C appears between the mild steel and Al(Fe,Mn)at 700℃ and 750℃,but absent at 800℃ due to the increased solubility of carbon in Mg *** is found that the growth of the intermetallic layer is controlled by diffusion mechanism,and Al and Mn are the dominant diffusing species in the whole interfacial reaction *** measuring the thickness of different layers,the growth constant was *** increases from 1.89(±0.03)×10^(-12)m^(2)·s^(-1)at 700℃ to 3.05(±0.05)×10^(-12)m^(2)·s^(-1)at 750℃,and 5.18(±0.05)×10^(-12)m^(2)·s^(-1)at 800℃.Meanwhile,the content of Fe is linearly increased in AZ91D with the increase of holding time at 700℃ and 750℃,while it shows a significantly increment after holding for 8 h at 800℃,indicating holding temperature is more crucial to determine the Fe content of AZ91D than holding time.

关键词： AZ91D mild steel interface reaction intermetallic growth kinetics

High-entropy oxide-supported platinum nanoparticles for efficient hydrogen evolution reaction

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Rare Metals 2024年第4期43卷 1537-1546页

作者： Ming-Yu Fan jia-Jun Wang Jun Zhao hong Zhang Tian-Yi Ma Xiao-Peng Han Wen-bin Hu School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional Materials Key Laboratory of Advanced Ceramics and Machining TechnologyTianjin UniversityTianjin300350China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou350207China School of Science RMIT UniversityMelbourneVIC3000Australia

High-entropy oxides(HEOs)are a new class of single-phase structures with unique electronic and catalytic properties;therefore,it is worthwhile to explore their applications in *** this study,a Pt/(FeCoNiCrAl)_(3)O_(4)nanohybrid using HEO as a support was developed as an efficient catalyst for the hydrogen evolution reaction(HER).Pt/(FeCoNiCrAl)_(3)O_(4)exhibited high HER activity with a low overpotential of 22 mV at10 mA·cm^(-2),outperforming other binary,ternary,and quaternary *** HER activity of Pt/(FeCoNiCrAl)_(3)O_(4)was higher than that of a commercial Pt/C with a significantly lower Pt *** catalyst exhibited good activity and long-term stability(60 h)in an electrolytic water-splitting *** good activity can be attributed to the fact that the introduction of Pt effectively facilitates electronic interactions between Pt and the *** addition,the HEO substrate was more favorable for dispersing Pt particles,optimizing the electrochemical specific surface area,and significantly reducing the charge resistance of the *** study extends the application of HEOs in electrocatalysis and demonstrates the promising prospects of HEOs as supports for electrocatalysts.

关键词： High-entropy oxides Hydrogen evolution reaction Nanohybrid Water electrolysis

Optimizing intrinsic cocatalyst activity and light absorption efficiency for efficient hydrogen evolution of 1D/2D ReS_(2)-CdS photocatalysts via control of ReS_(2)nanosheet layer growth

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Journal of Materials Science & Technology 2024年第1期168卷 103-113页

作者： Ghufran Aulia bin Azizar Jong Wook hong Department of Chemistry University of UlsanUlsan 44610Korea

The visible-light-driven hydrogen evolution is extremely important,but the poor charge transfer capa-bility,a sluggish evolution rate of hydrogen,and severe photo-corrosion make photocatalytic hydrogen evolution *** this study,we present 1D/2D ReS_(2)-CdS hybrid nanorods for photocatalytic hy-drogen evolution,comprised of a ReS_(2)nanosheet layer grown on CdS *** found that precise control of the contents of the ReS_(2)nanosheet layer allows for manipulating the electronic structure of Re in the ReS_(2)-CdS hybrid *** ReS_(2)-CdS hybrid nanorods with optimal ReS_(2)nanosheet layer content dramatically improve photocatalytic hydrogen evolution ***,photocatalytic hydro-gen evolution activity(64.93 mmol g^(−1)h^(−1))of ReS_(2)-CdS hybrid nanorods with ReS_(2)nanosheet layers(Re/Cd atomic ratio of 0.051)is approximately 136 times higher than that of pure CdS nanorods under visible light ***,intimated coupling of the ReS_(2)nanosheet layer with CdS nanorods reduced the surface trap-site of the CdS nanorods,resulting in enhanced photocatalytic *** de-tailed optical and electrical investigations demonstrate that the optimal ReS_(2)nanosheet layer contents in the ReS_(2)-CdS hybrid nanorods can provide improved charge transfer capability,catalytic activity,and light absorption *** study sheds light on the development of photocatalysts for highly efficient photocatalytic hydrogen evolution.

关键词： Photocatalyst Hydrogen evolution reaction ReS_(2)-CdS heterostructure Control of ReS_(2)nanosheet layer growth Optimization of cocatalyst activity and light absorption

Intracellular redox potential-driven live-cell synthesis of CdSe quantum dots in Staphylococcus aureus

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Science China Chemistry 2024年第3期67卷 990-999页

作者： Cai-Qin Wu An-An Liu Xu Li jia-Wei Tu Juan Kong Ling-Ling Yang jian-hong jia Chuan Wang bin Hu Zhi-Xiong Xie Dai-Wen Pang The Institute for Advanced Studies College of Chemistry and Molecular SciencesCollege of Life SciencesHubei Key Laboratory of Cell HomeostasisWuhan UniversityWuhan 430072China Research Center for Analytical Sciences College of ChemistryState Key Laboratory of Medicinal Chemical BiologyTianjin Key Laboratory of Biosensing and Molecular RecognitionFrontiers Science Center for New Organic MatterFrontiers Science Center for Cell Responsesand Haihe Laboratory of Sustainable Chemical TransformationsNankai UniversityTianjin 300071China

Biosynthesized semiconductor quantum dots(QDs) have bright fluorescence,adjustable particle sizes,and environmental friendliness,endowing them with convenience and potential for biological *** to the unclear mechanism of the cellular environment on the live-cell synthesis of QDs,it is still difficult to regulate their optical ***,the critical role of the intracellular redox environment in regulating the fluorescence properties of biosynthesized CdSe QDs in Staphylococcus aureus(***) has been *** glutathione peroxidase(GPx) activity directly affects the intracellular H_(2)O_(2) produced in the SeO_(3)^(2-) reduction,which further manipulates the glutathione redox cycle to determine the content of low-valence *** a result,the fluorescence intensity of the synthesized CdSe QDs increases by 60% in the GPx overexpressed *** cellular redox potential that is controlled by the GSH redox cycle provides the driving force for the reduction of SeO_(3)^(2-),facilitating the synthesis of CdSe QDs in *** *** proposed mechanism of the cellular redox state provides a new perspective for regulating the synthesis of semiconductor nanomaterials in live cells.

关键词： redox H_(2)O_(2) peroxidase quantum dot Staphylococcus aureus