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Size effects on process performance and product quality in progressive microforming of shafted gears revealed by experiment and numerical modeling

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Advances in Manufacturing 2023年第1期11卷 1-20页

作者： Jun-yuan Zheng Hui Liu Ming-Wang fu Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongPeople’s Republic of China Research Institute for Advanced Manufacturing The Hong Kong Polytechnic UniversityHung HomKowloonHong KongPeople’s Republic of China

As one of the indispensable actuating components in micro-systems,the shafted microgear is in great production *** is a manufacturing process to produce microgears to meet the *** to the small geometrical size,there are uncertain process performance and product quality issues in this production *** this study,the shafted microgears were fabricated in two different scaling factors with four grain sizes using a progressively extrusion-blanking *** explore the unknown of the process,grain-based modeling was proposed and employed to simulate the entire forming *** results show that when the grains are large,the anisotropy of single grains has an obvious size effect on the forming behavior and process performance;and the produced geometries and surface quality are worsened;and the deformation load is *** deformation zones were identified in the microstructures with different hardness and distributions of stress and *** simulation by using the proposed model successfully predicted the formation of zones and revealed the inhomogeneous deformation in the forming *** undesirable geometries of microgears including material unfilling,burr and inclination were observed on the shaft and teeth of gear,and the inclination size is increased obviously with grain *** avoid the formation of inclination and material unfilling,the punch was redesigned,and a die insert was added to constraint the bottom surface of the gear *** new products had then the better forming quality.

关键词： Microforming Microprocess performance Microforming quality Size effect affected deformation behavior Die design optimization

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Nmnoparticle-mediated double-stranded RNA delivery system: A promising approach for sustainable pest management

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Insect Science 2021年第1期28卷 21-34页

作者： Shuo Yan Bin-yuan ren Jie Shen Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management College of Plant ProtectionChina Agricultural UniversityBeijingChina National Agricultural Technology Extension and Service Center BeijingChina

RNA interference(RNAi)targeting lethal genes in insects has great potential for sustainable crop *** with traditional double-stranded(ds)RNA delivery systems,nanoparticles such as chitosan,liposomes,and cationic dendrimers offer advantages in delivering dsRNA/small interfering(si)RNA to improve RNAi efficiency,thus promoting the development and practice of RNAi-based pest management ***,we illustrate the limitations of traditional dsRNA delivery systems,reveal the mechanism of nanoparticle-mediated RNAi,summarize the recent progress and successful applications of nanoparticle-mediated RNAi in pest management,and finally address the prospects of nanoparticle-based RNA pesticides.

关键词： dsRNA delivery nanocarrier pest control RNAi efficiency RNA pesticide

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Through-Thickness Texture Gradient in Hot-Rolled 25Mn-2.5Si-2Al TWIP Steel

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Journal of Iron and Steel Research International 2013年第4期20卷 46-53页

作者： SU Yu LI Lin fu ren-yu Department of Materials Science and Engineering Shanghai University

Texture is one of the important factors affecting sheet metal forming *** through-thickness texture gradient during the hot-rolling process of twinning induced plasticity（TWIP）steel sheet was investigated using electron backscatter diffraction and X-ray *** increasing reduction of the TWIP steel,the fraction of∑1 decreased,whereas the fractions of∑3,∑9,and∑*** 53%reduction,a similar trend could be found from its surface to the *** gradients of intensities of the fibers decreased with increasing hot-rolling *** intensities of face-centered cubic（fcc）shear textures E and Y were higher in the center than that at the surface for both *** 20% reduction,the intensity of fcc plain strain texture S orientation increased from the center to the surface.

关键词： twinning induced plasticity steel texture grain boundary character twinning

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Distribution control and formation mechanism of gas inclusions in directionally solidified Al2O3-Er3Al5O12-ZrO2 ternary eutectic ceramic by laser floating zone melting

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Journal of Materials Science & Technology 2021年第7期66卷 21-27页

作者： Haijun Su yuan Liu Qun ren Zhonglin Shen Haifang Liu Di Zhao Guangrao Fan Min Guo Jun Zhang Lin Liu Hengzhi fu Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518057China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an710072China

Distribution control and formation mechanism of gas inclusions formed in directionally solidified Al2O3-Er3Al5O12-ZrO2 eutectic ceramic rods are explored during laser floating zone melting. In atmospheric environment, highly-dense bubble-free eutectic rods are well fabricated at low solidification rate(<25μm/s). Gas inclusions form intermittently when the solidification rate is in the range of 25-50 μm/s,but produce continuously at higher solidification rates(100-200 μm/s). The gas inclusions exhibit an elongated finger-like pattern along the growth direction, which of the maximum value of diameter first increases and then decreases with increasing the solidification rate. Meanwhile, the volume fraction of gas inclusions increased gradually with the solidification rate. Based on the effect of surface tension gradient, heterogeneous nucleation of gas bubbles is evaluated to be the primary formation mechanism of gas inclusions.

关键词： Directional solidification Gas inclusions Eutectic oxide Laser floating zone melting Formation mechanism

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High temperature electrochemical discharge performance of LaFeO3 coated with C/Ni as anode material for NiMH batteries

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Progress in Natural Science:Materials International 2022年第6期32卷 684-692页

作者： Kailiang ren Jiajia Miao Wenzhuo Shen Huanhuan Su Yunpeng Pan Jiajin Zhao Xiangyu Pan yuan Li Yaokun fu Lu Zhang Shumin Han State Key Laboratory of Metastable Materials Science and Technology Yanshan University School of Environmental and Chemical Engineering Yanshan University

Perovskite LaFeO3is considered as a promising new anode material for nickel/metal hydride batteries due to its low cost,environmental friendliness and high temperature ***,the poor conductivity of LaFeO3material restricts the discharge ability,which is problematic for its future widespread *** solve the above issue,in this study,we prepared C/Ni-coated LaFeO3composite in view of the excellent electrical conductivity of carbon and nickel *** show that the C/Ni-coated LaFeO3composite delivers remarkably increased discharge capacity of ～345 mAh g-1at 60℃ in contrast to ～267 mAh g-1for pure ***,the carbon and nickel not only increase the electrical conductivity of the LaFeO3but also reduces the agglomeration of the LaFeO3,therefore,the C/Ni-coated LaFeO3composite serves superior long cycle-life,which maintains 60.9% after 100 cycles(52.9% for the LaFeO3sample).In overall,the electrochemical behavior of the C/Ni-coated LaFeO3composite confirms its high potential as nickel/metal hydride batteries for energy storage applications.

关键词： Energy storage Perovskite-type oxide Nickel metal hydride batteries LaFeO3 Electrochemical performance

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Preparation and characterization of biomimetic adsorbent from poly-3-hydroxybutyrate

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Journal of Environmental Sciences 2010年第8期22卷 1267-1272页

作者： Xiaoxuan Zhang Chaohai Wei Qincong He yuan ren College of Environmental Science and Engineering South China University of Technology Guangzhou 510006 China College of Chemistry and Material Science Anhui Normal University Wuhu 241000 China

Biomimetic adsorbent named as PHBBMA was prepared from lipophilic poly-3-hydroxybutyrate （PHB） by a modified double emulsion solvent evaporation method. PHBBMA, characterized by using scanning electron microscope and nitrogen adsorption/desorption measurements, is porous spherical particles. The characterization with the thermal gravimetric analysis and differential scanning calorimetry, 1 H nuclear magnetic resonance and Fourier transform infrared spectroscopy showed that PHBBMA preparation was a physical process without chemical reaction. The adsorption of PHBBMA for o-nitrochlorobenzene （o-NCB） was fitted better by Langmuir model than by Freundlich model, while the pseudo second-order model fitting was better than the pseudo first-order model fitting. The maximal adsorption capacity of PHBBMA for o-NCB was 57.83 mg/g at 30°C, although its specific surface area （S BET ） was only 8.45 m 2 /g. PHBBMA is a safe and environmental friendly adsorbent with high adsorption capacity because its component is innocuous and biodegradable PHB produced reusing wastes and contaminants, no byproduct can produced, and its ester and hydrocarbyl groups have strong affinity with organochlorine compounds. The further work will focus on the modification and improvement of PHBBMA in order to increase its S BET and adsorption capacity.

关键词： poly-3-hydroxybutyrate solvent evaporation technique biomimetic adsorbent adsorption

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A comparison of the catalytic hydrogenation of 2-amylanthraquinone and 2-ethylanthraquinone over a Pd/Al2O3 catalyst

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Frontiers of Chemical Science and Engineering 2017年第2期11卷 177-184页

作者： Enxian yuan Xiangwei ren Li Wang Wentao Zhao Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072 China School of Science Tianjin University Tianjin 300072 China

The hydrogenation of 2-ethylanthraquinone （eAQ）, 2-tert-amylanthraquinone （taAQ） and their mixtures with molar ratios of 1：1 and 1：2 to the corresponding hydroquinones （eAQH2 and taAQH2） were studied over a Pd/Al2O3 catalyst in a semi-batch slurry reactor at 60 ℃ and at 0.3 MPa. Compared to eAQ, TaAQ exhibited a significantly slower hydrogenation rate （about half） but had a higher maximum yield of H2O2 and a smaller amount of degradation products. This can be ascribed to the longer and branched side chain in taAQ, which limits its accessibility to the Pd surface and its diffusion through the pores of the catalyst. Density functional theory calculations showed that it is more difficult for taAQ to adsorb onto a Pd （111） surface than for eAQ. The hydrogenation of the eAQ/taAQ mixtures had the slowest rates, lowest H2O2 yields and the highest amounts of degradation products.

关键词： hydrogenation hydrogen peroxide anthraquinone Pd catalyst AO process

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Polymerization of fluorescent analogue of plant actin in vitro and in vivo

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Chinese Science Bulletin 2000年第17期45卷 1583-1586页

作者： ren Haiyun yuan Ming Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education College of Life SciencesBeijing Normal UniversityBeijing 100875China Key Laboratory of Plant Physiology and Biochemistry of Ministry of Agriculture Department of Plant SciencesCollege of Biological SciencesChina Agricultural UniversityBeijing 100094China

Maize pollen actin has been labeled with Oregon Green 488 iodoacetamide. A yield of 3 mg fluorescent actin analogue has been obtained from 10 mg of maize pollen actin, which is 99% in purity and the dye/protein ratio is 72%. In the presence of Mg2+ and K+, the fluorescent actin analogue polymerized into filaments in vitro. Green fluorescent filaments were observed when the fluorescent actin was introduced into living plant cells by microinjection, indicating that the fluorescent actin analogue functions similarly to the native actin.

关键词： fluorescent actin analogue actin filaments microinjection.

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Facile synthesis of molybdenum carbide nanoparticles in situ decorated on nitrogen-doped porous carbons for hydrogen evolution reaction

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Journal of Energy Chemistry 2019年第5期28卷 78-84页

作者： Jin-Tao ren Yue-Jun Song Zhong-Yong yuan National Institute for Advanced Materials School of Materials Science and EngineeringNankai UniversityTianjin 300350China Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)Nankai UniversityTianjin 300071China

Molybdenum-based electrocatalysts are promising candidates of platinum (Pt)-based materials in electrocatalyzing hydrogen evolution reaction (HER), due to their cost-efficient and resembled electronic properties. Reported herein is the preparation of molybdenum carbide nanoparticles uniformly decorated on nitrogen-modified carbons (Mo2C/NC) through the carbonization of Mo-based polymers under hydrogen atmosphere by using poly(p-phenylenediamine) and ammonium heptamolybdate polymer analogue as precursors. And the molybdenum nitride nanoparticles loaded on porous N-doped carbons (Mo2N/NC) are also fabricated by calcination the polymer precursors in nitrogen gas. The Mo2C/NC shows more excellent electrocatalytic activity than Mo2N/NC in 0.5 M H2SO4, together with robust long-term durability. The well-crystalline nanoparticles and the increased electron conductivity are the main characters responded for the high catalytic efficiency of the fabricated electrocatalysts. This easily fabrication procedure may provide a facile route to prepare non-noble metal carbide/nitride catalysts featuring wellengineered structural and textural peculiarities for realistic energy conversion system.

关键词： Molybdenum carbide Molybdenum nitride Nitrogen-doped carbon Hydrogen evolution reaction Electrocatalysis

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Next-generation sequencing and single-cell RT-PCR reveal a distinct variable gene usage of porcine antibody repertoire following PEDV vaccination

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Science China(Life Sciences) 2020年第8期63卷 1240-1250页

作者： ren Li Fang fu Li Feng PingHuang Liu State Key Laboratory of Veterinary Biotechnology Harbin Veterinary Research InstituteChinese Academy of Agricultural SciencesHarbin 150001China

Porcine epidemic diarrhea virus(PEDV)is the most common diarrhea-causing pathogen in newborn *** clarifications of the overall antibody repertoire and antigen-specific antibody repertoire are essential to provide important insights into the B-cell response and reshape new ***,we applied next-generation sequencing(NGS)technology to investigate immunoglobulin(Ig)variable(V)gene segment usage of swine B-cells from peripheral blood lymphocytes(PBL)and mesenteric lymph node(MLN)cells following PEDV *** identified the transcripts of all functional Ig V-genes in antibody ***1 S2,IgKV1-11,and IgLV3-4 were the most prevalent gene segments for heavy,kappa,and lambda chains,respectively,in PBL and *** previous studies,IgKV1,instead of IgKV2,and IgLV3,instead of IgLV8,were the prevalent Ig V-gene families for kappa and lambda light chains,*** further examined the antibody repertoire of PEDV spike-specific B cells by single-cell *** contrast to the overall antibody repertoire,Ig V-gene segments of PEDV spike-specific B cells preferentially adopted IgHV1-4 and IgHV1-14 for heavy chain,IgKV1-11 for kappa chain,and IgLV3-3 for lambda *** results represent a comprehensive analysis to characterize the Ig V-gene segment usage in the overall and PEDV spike-specific antibody repertoire in PBL and MLN.

关键词： porcine epidemic diarrhea virus(PEDV) next-generation sequencing(NGS) single-cell RT-PCR antibody repertoire

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