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Transient temperature characteristics of friction clutch disc considering thermal contact conductance under sliding conditions

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Friction 2023年第12期11卷 2253-2263页

作者： Yuwei LIU Yuanzhi SUN Ziyin GAO Fuhao YE pei tang School of Mechanical Electronic and Information Engineering China University of Mining and Technology-BeijingBeijing 100083China China North Vehicle Research Institute Beijing 100072China Huawei Machine Co. Ltd.Dongguan 523808China

High temperatures are generated due to the sliding contacts between the rubbing surfaces of the friction clutch *** this work,by considering the effective thermal contact conductance under sliding conditions,a simulation model of a two-dimensional transient temperature field of the clutch disc was developed.A numerical solution to obtain the surface temperature at different radii was presented based on the finite difference *** with the experimental data,the proposed model for estimating the surface temperature is more accurate than the conventional prediction *** results showed that the errors of the calculated temperatures at radii of 114 and 106 mm have obviously reduced by 12.98%and 12.60%,*** addition,the influences of pressure and relative speed on the surface temperature were *** temperature increases with the increase of the relative speed and pressure during the sliding period,and there is an interaction effect between pressure and speed on the surface temperature rise.

关键词： friction clutch finite difference analysis surface temperature thermal contact conductance

Asymmetric synthesis of ABC tricyclic systems in Daphniphyllum alkaloid

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Chinese Chemical Letters 2020年第3期31卷 685-688页

作者： Huijing Wang Qiuyan Dong Qinxia Xie pei tang Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial TechnologyWest China School of PharmacySichuan UniversityChengdu 610041China Chongqing Key Laboratory of Natural Product Synthesis and Drug Research School of Pharmaceutical SciencesChongqing UniversityChongqing 401331China Skaggs School of Pharmacy and Pharmaceutical Sciences University of California San DiegoLa Jolla 92093-0934United States

Efficient synthetic routs for the direct and rapid construction of[5-6-6]ABC tricyclic systems of daphmanidin A-type and calyciphylline A-type alkaloids have been successfully *** the daphmanidin A-type,the synthesis of[5-6-6]tricyclic framework utilize a HCl-mediated intramolecular Aldol reaction to construct the bicyclo[2.2.2]octane core and a thermal condensation to afford the ABC ring *** addition,for the calyciphylline A-type,an improved synthesis of ABC[5-6-6]tricyclic system was developed,featuring an introduction of methyl ester group at C2 before the Pd-catalyzed intramolecular oxidative alkylation to construct the desired bowl-shape tricyclic core with stereochemical control.

关键词： Daphniphyllum alkaloid Calyciohylline N 21-Deoxymacropodumine D ABC tricyclic framework Intramolecular Aldol reaction Pd-catalyzed intramolecular oxidative alkylation

One-step synthesis of carbon-supported copper nanoparticles from biomass for N-arylation of pyrazole

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Journal of Energy Chemistry 2018年第3期27卷 859-865页

作者： Wenjing Li Yongjun Gao pei tang Yao Xu Ding Ma inan 250002.Shandong China Beijing National Laboratory for Molecular Sciences.College of Chemistry and Molecular Engineering Peking University.Beijing 100871.China College of Chemistry&Environmental Science.Hebei University Baoding 071002HebeiChina

Carbon-supported copper catalyst was prepared for the first time in one-step with copper nitrate and corn stalk through calcination under different temperatures. Uniformly dispersed nanoparticles were obtained and were identified to be Cu（0） and Cu（Ⅰ） in XRD patterns. Excellent catalytic activity and selectivity were achieved in the N-arylation of pyrazole under ligand and protection gas free conditions. About90.4% of product yield was achieved with only 0.5 mol% of copper catalyst（Cu-C-300）, which was considerably more efficient than previous reports. XPS results suggested that the N-arylation of pyrazole activity was closely related to the surface Cu（Ⅰ） species.

关键词： Corn stalk Carbon-supported copper N-arylation Ligand-free

Achieving High Strength-plasticity of Nanoscale Lamellar Grain Extracted from Gradient Lamellar Nickel

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Chinese Journal of Mechanical Engineering 2022年第4期35卷 67-78页

作者： Zimeng Wang Yunfei Jia Yong Zhang pei tang Xiancheng Zhang Shantung Tu Key Laboratory of Pressure Systems and Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China

Traditional metallic materials usually face a dilemma between high strength and poor strain hardening ***,heterogeneous structured metallic materials have been found to obviously overcome the ***,gradient lamellar structure was fabricated through ultrasound-aided deep rolling technique in pure Ni with high stacking fault energy after heat *** gradient lamellar Ni was successively divided into the four ***-situ micropillar compression tests were conducted in diferent regions to reveal the corresponding microscopic mechanical *** characterization techniques were performed to explore underlying deformation mechanisms and the efects of microstructural parameters on deformation *** work demonstrates that the micropillar with near nanoscale lamellar thickness possesses excellent strength and *** one hand,the reason for high strength of near nanoscale micropillar is that the strength of micropillar increases with the decrease of lamellar thickness according to the Hall-Petch *** the other hand,numerous lamellar grain boundaries perpendicular to the loading direction is found to hinder the motion of slip bands,resulting in great strain hardening capacity in the near nanoscale lamellar micropillar.

关键词： Nanoscale lamellar structure Compression test Slip Dislocation

Unraveling the mechanism of potassium metal capacitor for highly efficient charge storage

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Science China Chemistry 2024年第5期67卷 1578-1588页

作者： Qianqian Yao pei tang Kunyao Peng Zhenyuan Miao Yuecong Chen Qingyun Dou Xingbin Yan Department of Materials Science and Engineering Sun Yat-sen UniversityGuangzhou 510275China South China Academy of Advanced Optoelectronics South China Normal UniversityGuangzhou 510006China

Although hybrid metal ion capacitors(MICs) are highly desired to achieve both high power density of supercapacitors and high energy density of rechargeable batteries, the mismatch problem of electrochemical kinetics of negative and positive electrodes in MICs hampers the realization of this goal. Here, a new hybrid capacitor concept-potassium metal capacitor(PMC) is proposed for the first time, where potassium metal and commercial activated carbon(AC) without any modification are applied as negative and positive electrodes, respectively, and the electrolyte is the same as that of non-aqueous potassium ion batteries. The simplest PMC prototype exhibits a good combination of high energy density(184.9 Wh kg^(-1)) and power density(12.4 kW kg^(-1)), which benefits from the synergistic effect of potassium metal and AC electrode. The former experiences fast potassium plating/striping during charging and discharging, and the later possesses complex multiple charge behaviors driven by low potential of potassium metal. Specifically, below open-circuit voltage, transportation of solvated cations in AC pores plays an important role;beyond this voltage, synergy actions of cations and anions, including adsorption/desorption of solvated cations and anions, and ions exchange between them, dominate the capacitance contribution. This work enriches the types of MICs, and deepens the understanding of the energy storage mechanism of non-aqueous hybrid metal capacitors.

关键词： hybrid capacitor potassium metal activated carbon charge storage mechanism

Synthesis,Crystal Structure,and Magnetic Property of One 3D Nickel Coordination Polymer Based on 2-Hydroxy-5-(3',5'-terephthalic acid)Pyridine and 1,4-Bis(1-imdazoly)benzene

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Chinese Journal of Structural Chemistry 2015年第10期34卷 1519-1524页

作者： tang pei-Qin HAO Lu-Jiang FAN Li-Ming LIU Xin-Zheng LI Bin ZHANG Xiu-tang Advanced Material Institute of Research College of Chemistry and Chemical EngineeringQilu Normal University College of Biological Engineering Qilu University of Technology State Key Laboratory of Crystal Materials Shandong University

One novel nickel coordination polymer, {[Ni（OTP）（bib）1.5（H2O）]·2H2O}n（1, H2 OTP = 2-hydroxy-5-（3＇,5＇-terephthalic acid） pyridine, bib = 1,4-bis（1-imdazoly）benzene）, has been synthesized and characterized by elemental analysis（EA）, IR, powder X-ray diffraction（PXRD）, and thermogravimetric（TG） analyses. The crystal of 1 crystallizes in monoclinic, space group P21/n with a = 12.2860（5）, b = 13.8246（6）, c = 19.0140（8） A, β = 104.3870（1）°, V = 3128.2（2） A3, Z = 4, C32H28N7 Ni O8, Mr = 697.32, Dc = 1.481 g/cm^3, F（000） = 1444 and μ（Mo Kα） = 0.684 mm-1. The final R = 0.0704 and w R = 0.1764 for 5485 observed reflections with I 2σ（I） and R = 0.1087 and wR = 0.2010 for all data. Topology analysis reveals that complex 1 is a 3D 2-fold interpenetrated {4^4·6^6}-nov net based on the 1D [Ni（OTP）]n chain and the 2D [Ni2（bib）3]n sql sheet. And the variable-temperature magnetic susceptibility measurements exhibit weak antiferromagnetic coupling interaction.

关键词： 2-hydroxy-5-(3',5'-terephthalic acid)pyridine 1,4-bis(1-imdazoly)benzene nickel topology magnetic property

Concise syntheses of 13-methylprotoberberine and 13-methyltetrahydroprotoberberine alkaloids

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Chinese Chemical Letters 2022年第12期33卷 5080-5083页

作者： Wenchang Chen Xiaofen Yi Hongmin Qu Yu Chen pei tang Fener Chen Sichuan Research Center for Drug Precision Industrial Technology West China School of PharmacySichuan UniversityChengdu 610041China Engineering Center of Catalysis and Synthesis for Chiral Molecules Department of ChemistryFudan UniversityShanghai 200433China hanghai Engineering Center of Industrial Asymmetric Catalysis for Chiral Drugs Shanghai 200433China

The concise syntheses of eight 13-methylprotoberberine(13-MePB)and eight enantioenriched 13-methyltetrahydroprotoberberine(13-MeTHPB)alkaloids have been achieved in a tactically modular *** synthetic work features a one-pot metal-free Pictet-Spengler/Friedel-Crafts hydroxyalkylation/dehydration/oxidation sequence and a following highly enantioselective Ir-catalyzed *** such brevity and modularity,our developed synthetic route would be greatly beneficial to the efficient syntheses of existing natural products and new fully synthetic variants of 13-MePB and 13-MeTHPB family.

关键词： 13-Methylprotoberberine 13-Methyltetrahydroprotoberberine One-pot metal-free sequence Asymmetric hydrogenation

Synthesis and Characterization of Fluorine-containing Poly(ether ether ketone)s

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Chemical Research in Chinese Universities 2010年第4期26卷 672-674页

作者： ZHANG pei ZHAO Yun tang Xin-liang ZHOU Ming-ji JIAO Qing-ze School of Chemical Engineering and Environment Beijing Institute of Technology Beijing 100081 P. R. China

Poly（ether ether ketone）s（PEEK） are a class of high performance engineering thermoplastics known for their excellent thermal, mechanical, and electrical properties. This class of advanced materials has currently received considerable attention for potential application in aerospace, electronics, automobile and other high technology fields. However, it is difficult for PEEK to be processed because of their high melting temperature and poor solubility.

关键词： Fluorine-containing polymer Solubility Dielectric constant

Combined enzymatic hydrolysis and herbal extracts fortification to boost in vitro antioxidant activity of edible bird's nest solution

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Chinese Herbal Medicines 2021年第4期13卷 549-555页

作者： pei Ling tang Hooi Shin Goh Swee Seng Sia Department of Bioscience Faculty of Applied SciencesTunku Abdul Rahman University CollegeSetapak53300 Kuala LumpurMalaysia Nestlin Malaysia Sdn.Bhd. 3AJalan PayamasTaman Industri PayamasTangkak 84900JohorMalaysia

Objective:Edible bird’s nest(EBN)is a popular traditional tonic food in Chinese population for *** is one of the main EBN suppliers in the *** study aims to explore the best strategy to boost the antioxidant potential of EBN ***:In this study,the raw EBN(4%,mass to volume ratio)was initially enzymatic hydrolyzed using papain enzyme to produce EBN hydrolysate(EBNH),then spray-dried into powdered ***,4%(mass to volume ratio)of EBNH powder was dissolved in ginger extract(GE),mulberry leaf extract(MLE)and cinnamon twig extract(CTE)to detect the changes of antioxidant activities,***:Results obtained suggest that enzymatic hydrolysis significantly reduced the viscosity of 4%EBN solution from(68.12±0.69)m Pa·s to(7.84±0.31)m Pa·***,the total phenolic content(TPC),total flavonoid content(TFC),total soluble protein,DPPH scavenging activity and ferric reducing antioxidant power(FRAP)were substantially increased following EBN hydrolysis using papain *** addition,fortification with GE,MLE and CTE had further improved the TPC,TFC,DPPH scavenging activity and FRAP of the EBNH *** the samples,MLE-EBNH solution showed the most superior antioxidant potential at(86.39±1.66)%of DPPH scavenging activity and(19.79±2.96)mmol/L FeSO;of ***:This study proved that combined enzymatic hydrolysis and MLE fortification is the best strategy to produce EBN product with prominent in vitro antioxidant *** preliminary study provides new insight into the compatibility of EBN with different herbal extracts for future health food production.

关键词： antioxidant cinnamon twig edible bird’s nest enzymatic hydrolysis ginger mulberry leaves