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Microstructure and properties of Y_2O_3-doped steel-cemented WC prepared by microwave sintering

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Rare Metals 2013年第5期32卷 496-501页

作者： Jun-Ming Luo Ji-Lin xu zhen-Chen zhong School of Materials Science and Engineering Nanchang Hangkong University

Steel-cemented WC was prepared by ball milling, cold compacting and microwave sintering with Fe powder as the matrix, WC as the hard phase and the addition of rare earth Y2O3. The results show that the interface of the WC particles and Fe matrix exhibits excellent wettability and liquidity when the microwave sintering temperature reaches 1,280℃. The density and mechanical properties of the steel bonded WC carbides could be greatly improved, the hard phases become finer and more uniform dispersed owing to the addition of Y2O3. With the increase of the Y2O3 contents, the grain becomes uniform and fine first, and then gathers and grows up. The relative density, microhardness and bending strength all rise first, reaching the maximum values of 97.29 %, HV1024 and 1,267.60 MPa at 0.5 % Y2O3, respectively, and then decrease. Moreover, the relative density and mechanical properties of the steel-cemented WC with nano-Y2O3 are higher than that with micron-Y2O3, which indicates that the effect of nano-Y2O3 is better than that of the micron-Y2O3.

关键词： Y2O3 content Microwave sintering Steel-cemented WC

Theoretical Investigation on Regioselectivities of Diels-Alder Reactions by Conjugated Effect

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Chinese Journal of Chemistry 2020年第12期38卷 1696-1702页

作者： zhen-zhen xu Jian Zhao Dong-Xia Zhao zhong-Zhi Yang Jiangxi Province Key Laboratory of the Causes and Control of Atmospheric Pollution and School of Chemistry Biology and Materials ScienceEast China University of TechnologyNonchangJiangxi 330013China School of Chemistry and Chemical Engineering Liaoning Normal UniversityDalianLiaoning 116029China

of main observation and conclusion The regioselectivities of 76 Diels-Alder reactions between unsymmetrical dienes and dienophiles were investigated by local softness and generalized local softness at atomic and chemical bond view,respectively,where the reactivity descriptors were calculated by finite difference approximation and ABEEMan *** on local HSAB principle and matching criterion of local softness,reasonable explanation and prediction on regioselectivities of all reactions through ABEEMan model have been obtained,which are in agreement with the experimental ***,at n-bond level,while the 1-substituents of dienes were NH2/NMe2,and NEt2/because of the p-R conjugated effect between the lone pairs of Natom and the conjugated n-bond of the four double-bonded carbon atoms in diene,it made the dienophile not easy to approach diene by Manner A,hence,Manner B can forecast the ortho regioisomer as main product well,and Manner A *** to the other reactions,both Manner A and Manner B can predict their *** can be seen that the ABEEMan model can take the effect of the chemical environment on the reaction reactivity into account richly,especially the system includes n-bond and lone ***,the results through the finite difference approximation are not reasonable.

关键词： reactivity conjugated approximation

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高品质学校的内涵结构、建设困境与突破路径

教学与管理 2025年第1期 19-23页

作者：邓纯臻隆平陈书忠重庆师范大学生命科学学院重庆401331 四川省攀枝花市第七高级中学校四川攀枝花617005 重庆市育才中学校重庆400050

高品质学校的创建既是区域教育高质量发展的基本组成,也是助推教育强国、人才强国建设的实践基础。综合来看,学校内部维度的高品质是一种过程取向以及主观层面的高品质,外部维度的高品质是一种结果取向以及客观层面的高品质,高品质学校... 详细信息

高品质学校的创建既是区域教育高质量发展的基本组成,也是助推教育强国、人才强国建设的实践基础。综合来看,学校内部维度的高品质是一种过程取向以及主观层面的高品质,外部维度的高品质是一种结果取向以及客观层面的高品质,高品质学校包括学生、教师、管理者以及课程、课堂、课题六个核心的动力要素。当前,高品质学校的建设依然在前沿理论、本地生源、教育资源以及师资队伍等方面存在一些阻碍,对此,建议从学校文化、优质资源、课程体系、师资队伍、管评系统等五个维度探寻突破路径,以期找到高品质学校的创新之路、高品质之路。

关键词：教育高质量发展高品质学校中小学管理学校治理

Accumulated damage process of thermal sprayed coating under rolling contact by acoustic emission technique

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Frontiers of Mechanical Engineering 2016年第3期11卷 227-232页

作者： Jia xu zhen-yu ZHOU zhong-yu PIAO Key Laboratory of Special Purpose Equipment and Advanced Processing Technology (Zhejiang University of Technology) Ministry ofEducation and Zhejiang Province Hangzhou 310014 China Key Laboratory of Special Purpose Equipment and Advanced Processing Technology (Zhejiang University of Technology) Ministry ofEducation and Zhejiang Province Hangzhou 310014 China The StateKey Laboratory of Fluid Power Transmission and Control Hangzhou310027 China

The accumulated damage process of rolling contact fatigue （RCF） of plasma-sprayed coatings was investigated. The influences of surface roughness, loading condition, and stress cycle frequency on the accumulated damage status of the coatings were discussed. A ball-on- disc machine was employed to conduct RCF experiments. Acoustic emission （AE） technique was introduced to monitor thc RCF process of the coatings. AE signal characteristics were investigated to reveal the accumulated damage process. Result showed that the polished coating would resist the asperity contact and remit accumulated damage. The RCF lifetime would then extend. Heavy load would aggravate the accumulated damage status and induce surface fracture. Wear became the main failure mode that reduced the RCF lifetime. Frequent stress cycle would aggravate the accumulated damage status and induce interface fracture. Fatigue then became the main failure mode that also reduced the RCF lifetime.

关键词： accumulated damage spray coating rolling contact fatigue acoustic emission

婴儿肠道源长双歧杆菌B2-01的益生特性及其高密度培养

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食品科学 2025年第1期46卷 28-39页

作者：彭芸燕钟舒莹刘冬梅许喜林华南理工大学食品科学与工程学院广东广州510641

以广州市3月龄健康婴儿粪便中分离出的乳酸杆菌为研究对象,经分子生物学鉴定确认为长双歧杆菌(Bifidobacterium longum),命名为B2-01。对B2-01进行包括体外抗氧化活性和肝损伤保护活性在内的益生特性和高密度培养研究,结果表明:B2-01具... 详细信息

以广州市3月龄健康婴儿粪便中分离出的乳酸杆菌为研究对象,经分子生物学鉴定确认为长双歧杆菌(Bifidobacterium longum),命名为B2-01。对B2-01进行包括体外抗氧化活性和肝损伤保护活性在内的益生特性和高密度培养研究,结果表明:B2-01具有较强的1,1-二苯基-2-三硝基苯肼自由基、羟自由基、超氧阴离子自由基、2,2′-联氮-双-(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除能力和抗脂质过氧化能力;在最高作用水平(DMEM完全培养基中发酵上清液体积分数10%)下,过氧化氢损伤和乙醇损伤L02细胞存活率可分别提高至89.10%和91.38%,同时能显著降低肝细胞中转氨酶的活力;高密度培养研究优化后的最佳培养条件确定为酵母浸提粉添加量3.45%、葡萄糖2.48%、乳糖2.79%、细菌学蛋白胨3.00%、低聚半乳糖2.50%。在此优化条件下,发酵液的活菌数最高可达4.20×10^(9) CFU/m L,比优化前(7.71×10^(8) CFU/mL)提高5.45倍。

关键词：长双歧杆菌婴儿肠道抗氧化活性酒精肝保护高密度培养

PROGRESS IN PHASE INVERSION EMULSIFICATION FOR EPOXY RESIN WATERBORNE DISPERSIONS

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Chinese Journal of Polymer Science 2007年第2期25卷 137-143页

作者： zhen-zhong Yang State Key Laboratory of Polymer Physics and Chemistry Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

In this review, our recent work in phase inversion emulsification （PIE） for polymer （especially epoxy resin） waterborne dispersions is summarized. Based on experimental results about PIE process, the physical model is proposed which can guide the synthesis of the waterborne dispersions such as polymer/nanoparticle composite dispersion. In the presence of a latent curing catalyst, PIE can give a crosslinkable epoxy resin waterborne dispersion. The dispersions can form cured transparent coatings with some unique properties such as UV shielding. They are promising in functional coatings, waterborne resin matrices for composites, and sizing for high performance fibers.

关键词： Phase inversion emulsification Epoxy resin Waterborne dispersions.

Experimental investigation on frictional properties of stressed basalt fractures

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第6期15卷 1457-1475页

作者： zhen zhong Congqiang xu Lei Wang Yunjin Hu Fengshou Zhang School of Civil Engineering Shaoxing UniversityShaoxing312000China Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province Shaoxing UniversityShaoxing312000China Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai200092China Key Laboratory of Geotechnical&Underground Engineering of Ministry of Education Tongji UniversityShanghai200092China

The frictional strength and sliding stability of faults are crucial in interpreting earthquake mechanisms and ***,we report friction experiments on basalt fractures,using a self-designed triaxial apparatus that allows direct shear of samples under coupled hydro-mechanical ***(VS)and slide-hold-slide(SHS)experiments are performed on both bare and gouge-bearing surfaces of Xiashan basalt subjected to cyclic shear velocities at 1e30 mm/s,effective normal stresses of 1e5 MPa,and pore pressures of 70e300 *** measured basalt friction coefficients are in the range of 0.67e0.74,which is sensitive to gouge thickness,normal stress,and ***,a reduction in friction coefficient is observed with an increment in gouge thickness,normal stress,and pore *** on the microscopic observation of the pre-and post-shearing sliding surfaces,this weakening effect in friction coefficient can be attributed to powder ***,the VS test results reveal predominantly velocity-strengthening behavior at investigated slip velocities,and this velocity strengthening behavior does not appear to be influenced by variations in normal stress,gouge thickness,and ***,changes in sliding velocity and normal stress can lead to a shift between stable and unstable ***,stable sliding is favored by high sliding velocities and low normal stress applied in this ***,we analyze the experimental data by calculating the rate-and-state parameters using the rate-and state-dependent friction(RSF)***,the calculated friction rate parameter(a-b)supports the velocity-strengthening *** frictional relaxation(Dmc)during hold periods and frictional healing(Dm)upon re-shearing are linearly proportional to the logarithmic hold time,which may be attributed to the growth in true contact area with hold *** study sheds light on the roles of sliding velocity,and gouge thickness in controlling f

关键词： Rock friction Basalt fracture Gouge Velocity-strengthening behavior Frictional healing

Doping-induced charge transfer in conductive polymers

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Chinese Chemical Letters 2024年第1期35卷 45-51页

作者： Siyi Luo zhen xu Fei zhong Hui Li Lidong Chen State Key Laboratory of High Performance Ceramics and Superfine Microstructures Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Molecular doping has become a widely used method to modulate the electric performance of organic semiconductors(OSC).Highly effective charge transfer during molecular doping is desired to achieve ideal electrical *** types of charge transfer mechanisms are widely accepted in molecular doping process:integer charge transfer(ICT)and charge transfer complex(CTC).In this review,fundamental principles of two mechanisms are revisited and the characterization methods are *** key points for the formation of two mechanisms are highlighted from aspects of molecular structure and process ***,the strategies to improve the proportion of ICT are ***,the challenges and perspectives for future developments in the molecular doping of polymer semiconductors are provided.

关键词： Molecular doping Charge transfer Integer charge transfer Charge transfer complex Conjugated polymer

QUANTIFYING THE SHORT LIFETIME WITH TCSPC-FLIM:FIRST MOMENT VERSUS FITTING METHODS

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Journal of Innovative Optical Health Sciences 2013年第4期6卷 1-10页

作者： LINGLING xu zhong-CHAO WEI SHAOQUN ZENG zhen-LIHU ANG Britton Chance Center for Biomedical Photonics Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology Wuhan 430074 P.R.China Key Laboratory of Biomedical Photonics of Ministry of Education Department of Biomedical Engineering Huazhong University of Science and Technology Wuhan 430074 P.R.China Laboratory of Nanophotonic Functional Materials and Devices South China Normal University Guangzhou 510006P.R.China

Combing the time corelated single photon counting(TCSPC)with fuorescence lifetime imaging microscopy(FLIM)provides promising opportunities in revealing important information on the microenvironment of cells and tissues,but the applications are thus far mainly limited by the accuracy and precision of the TCSPC-FLIM *** we present a comprehensive in-vestigation on the perforance of two data analysis methods,the first moment(M_(1))method and the conventional least squares(Fitting)method,in quantifying fuorescence *** found that the Mp method is more superior than the Fitting method when the lifetime is short(70-400ps)or the signal intensity is weak(<10^(3) photons).

关键词： Fluorescence lifetimne imaging tim-correlated single photon counting the distribution of the first moment(M_(1))