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Experimental and Internal Flow Investigation on the Performance of a Hydraulic Retarder with Different Liquid-Filled Amount and Blade Inclination Angles

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Journal of Thermal Science 2022年第3期31卷 923-933页

作者： DAI Cui DONG Liang ZHANG Xing zhu Jiancheng LIN Haibo School of Energy and Power Engineering Jiangsu UniversityZhenjiang212013China Sichuan Provincial Key Lab of Process Equipment and Control Sichuan University of Science&EngineeringZigong643000China Research Center of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang212013China Pipeline Research Design Center PipeChina North Pipeline CompanyLangfang065000China

In order to study the variation of brake torque,vibration,pressure fluctuation,exterior noise and internal flow for a hydraulic retarder with different inclination angles and liquid-filled amount,a bench-scale hydraulic retarder was *** INV3020 data collection system was used for the synchronous acquisition of brake torque,vibration,pressure fluctuation and exterior noise *** were performed with different inclination angles(90°and 75°)and six liquid-filled amount(50 vol%,60 vol%,70 vol%,80 vol%,90vol%and 100 vol%).The torque-volume ratio was proposed to accurately analyze the influence of inclination angle on the liquid volume in stator and rotor and the brake *** multiphase flow model was employed to capture the volume and velocity *** research shows that the brake performance improves and the vibration increases with the decrease of inclination angle and the increase of liquid-filled *** pressure fluctuation increases as the liquid-filled amount increases,while the lower inclination angle effectively lowers the pressure fluctuation *** sound pressure level trends upward with increasing liquid-filled amount,and the lower inclination angle can effectively reduce the *** volume distribution of the liquid phase under different liquid-filled amount is basically *** lower inclination angle can induce more vortexes.

关键词： hydraulic retarder blade inclination angle liquid-filled amount brake torque vibration pressure fluctuation noise numerical calculation

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Relaxed Stability Criteria for Time-Delay Systems:A Novel Quadratic Function Convex Approximation Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 996-1006页

作者： Shenquan Wang Wenchengyu Ji Yulian Jiang Yanzheng zhu Jian Sun College of Electrical and Electronic Engineering Changchun University of TechnologyChangchun 130012China the College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China Key Laboratory of Complex Systems Intelligent Control and Decision Beijing Institute of TechnologyBeijing 100081China

This paper develops a quadratic function convex approximation approach to deal with the negative definite problem of the quadratic function induced by stability analysis of linear systems with time-varying *** introducing two adjustable parameters and two free variables,a novel convex function greater than or equal to the quadratic function is constructed,regardless of the sign of the coefficient in the quadratic *** developed lemma can also be degenerated into the existing quadratic function negative-determination(QFND)lemma and relaxed QFND lemma respectively,by setting two adjustable parameters and two free variables as some particular ***,for a linear system with time-varying delays,a relaxed stability criterion is established via our developed lemma,together with the quivalent reciprocal combination technique and the Bessel-Legendre *** a result,the conservatism can be reduced via the proposed approach in the context of constructing Lyapunov-Krasovskii functionals for the stability analysis of linear time-varying delay ***,the superiority of our results is illustrated through three numerical examples.

关键词： Equivalent reciprocal combination technique quadratic function convex approximation approach stability timevarying delay

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Real-Time Iterative Compensation Framework for Precision Mechatronic Motion Control Systems

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IEEE/CAA Journal of Automatica Sinica 2022年第7期9卷 1218-1232页

作者： Chuxiong Hu Ran Zhou Ze Wang Yu zhu Masayoshi Tomizuka State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084 Beijing Key Laboratory of Precision/Ultra-Precision Manufacture Equipments and Control Tsinghua UniversityBeijing 100084China Department of Mechanical Engineering University of CaliforniaBerkeleyCA 94720-1740 USA IEEE

With regard to precision/ultra-precision motion systems,it is important to achieve excellent tracking performance for various trajectory tracking tasks even under uncertain external *** this paper,to overcome the limitation of robustness to trajectory variations and external disturbances in offline feedforward compensation strategies such as iterative learning control(ILC),a novel real-time iterative compensation(RIC)control framework is proposed for precision motion systems without changing the inner closed-loop ***,the RIC method can be divided into two parts,i.e.,accurate model prediction and real-time iterative *** accurate prediction model considering lumped disturbances is firstly established to predict tracking errors at future sampling *** light of predicted errors,a feedforward compensation term is developed to modify the following reference trajectory by real-time iterative *** the prediction and compen-sation processes are finished in a real-time motion control sampling *** stability and convergence of the entire control system after real-time iterative compensation is analyzed for different *** simulation results consistently demonstrate that the proposed RIC framework possesses satisfactory dynamic regulation capability,which contributes to high tracking accuracy comparable to ILC or even better and strong robustness.

关键词： Precision motion control prediction model real-time iterative compensation trajectory tracking

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Increasing seed lint fiber density for promoting cotton yield:Opportunities and challenges

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Molecular Plant 2024年第10期17卷 1490-1493页

作者： Tianlun Zhao Jinhong Chen Shuijin zhu Qian-Hao zhu College of Agriculture and Biotechnology Zhejang UniversityHangzhou 310058China institute of Hainan Zhejang UniversitySanya 572025China CSIRO Agriculture and Food GPO Box 1700CanberraACT 2601Australia

Cotton fibers are single-celled and cellulose-enriched epidermal seed hairs and the most important natural fibers for the global textile *** seeds produce two distinct types of fibers:lint(long)and fuzz(short).Lint is the most economically valuable product of cotton,despite seeds being one of the major sources of edible oil and feeds of ruminant animals and fuzz having usages in multiple industrial products(Maeda et al.,2023).Increasing lint yield is therefore the primary goal of all cotton breeding programs *** yield is determined by plants per unit area,bolls per plant,boll weight,and lint *** yields of modern elite cotton cultivars are mainly due to the increased lint percentage,and therefore improving the lint percentage will continue to be the main breeding strategy for pursuing ever-higher lint yields.

关键词： breeding fibers cotton

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Small-sized Ni-Co/Mo_(2)C/Co_(6)Mo_(6)C_(2)@C for efficient alkaline and acidic hydrogen evolution reaction by an anchoring calcination strategy

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Frontiers of Chemical Science and Engineering 2024年第5期18卷 95-103页

作者： Jianxia Gu Ying zhu Haiyan Zheng Chunyi Sun Zhongmin Su Department of Chemistry Xinzhou Normal UniversityXinzhou 034000China School of Chemistry Northeast Normal UniversityChangchun 130024China

A novel,cheap and highly efficient Ni-Co/Mo_(2)C/Co_(6)Mo_(6)C_(2)@C nanocomposite has been successfully constructed through simple one-step carbonization method in a nitrogen *** in the precursor can effectively anchor molybdenum-based Keggin-type polyoxometallate and NiCo-layered double hydroxide through electrostatic and coordination interactions,which avoids the aggregation of catalyst particles during the pyrolysis *** optimization,the obtained Ni-Co/Mo_(2)C/Co_(6)Mo_(6)C_(2)@C possesses small size(3-8 nm),large specific surface area and hierarchical pore *** importantly,Ni-Co/Mo_(2)C/Co_(6)Mo_(6)C_(2)@C presents remarkable hydrogen evolution reaction activity with low overpotentials in 0.5 mol·L^(-1)H_(2)SO_(4)(102.3 mV)and 1 mol·L^(-1)KOH(95 mV)to afford the current density of 10 mA·cm^(-2),as well as small Tafel slopes of 82.49 and 99.92 mV·dec^(-1),***,this catalyst also shows outstanding stability for 12 h without a significant change in current *** excellent catalytic performance of Ni-Co/Mo_(2)C/Co_(6)Mo_(6)C_(2)@C can put down to the synergistic effect between multiple components and the small size of the *** work provides unique insights into the preparation of efficient transition metal-based catalysts for HER.

关键词： polyoxometallates layered double hydroxide transition metal-based electrocatalysts hydrogen evolution reaction

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Catalyst-free,radical-mediated intermolecular 1,2-arylheteroarylation of alkenes by cleaving inert C–C bond

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Science China Chemistry 2021年第10期64卷 1703-1708页

作者： Meishan Ji Xinxin Wang Jige Liu Xinxin Wu Chen zhu Key Laboratory of Organic Synthesis of Jiangsu Province College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China Key Laboratory of Synthetic Chemistry of Natural Substances Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

A novel photoinduced intermolecular 1,2-arylheteroarylation of alkenes and the efficient synthesis of valuable polyarylalkanes are *** reaction is operationally simple,proceeds under mild conditions and with no additional catalyst and *** strategically designed radical cascade reaction is enabled by electron transfer,and involves cleavage of an inert C–C *** process features broad functional group compatibility as well as high product transformability.

关键词： alkene difunctionalization arylation catalyst-free C–C activation functional group migration radical reactions

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Hepatocellular carcinoma: Current situation and challenge

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Hepatobiliary & Pancreatic Diseases International 2019年第4期18卷 303-304页

作者： Zhao Li Ji-Ye zhu Department of Hepatobiliary Surgery Peking University People’s HospitalBeijing 100044China Peking University Institute for Organ Transplantation Beijing 100044China Beijing Key Laboratory of Liver Cirrhosis and Liver Cancer Beijing 100044China

Hepatocellular carcinoma(HCC)ranks the fourth cause of cancer-related death worldwide[1].More than 50%newly diagnosed HCC patients are in China,while 70%of them are at advanced stage when they are diagnosed[2].These patients have lost the opportunity of radical surgery and can only receive palliative ***,the modality for these advanced stage HCC patients mainly include:targeted therapy,interventional therapy,chemotherapy,radiotherapy,and immunotherapy.

关键词： chemotherapy patients therapy

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Examination on the wear process of polyformaldehyde gears under dry and lubricated conditions

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Friction 2021年第3期9卷 538-550页

作者： Guoda YU Huaiju LIU Ken MAO Caichao zhu Zehua LU State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400030China School of Engineering the University of WarwickCoventry CV47ALUK

This study presents the results of detailed wear process examination on polyformaldehyde gears under both dry and lubricated conditions.A multi-purpose durability test rig was employed to study the wear performance of polyformaldehyde gear *** wear behaviors of polyformaldehyde gears under dry and oil-lubricated operating conditions were characterized via measurements of gear tooth surface micro-topography and tooth profile *** the dry running condition,a hump and a gully appear on the tooth surface in the pitch line area of the driving gear and the driven wheel,*** largest amount of wear was observed around the tooth root of the driving ***,the gear tooth wear pattern with lubrication is different from that under the dry running condition.

关键词： polyformaldehyde gear lubrication wear surface damage

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Revealing the anti-sintering phenomenon on silica-supported nickel catalysts during CO_(2)hydrogenation

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Journal of Environmental Sciences 2024年第6期140卷 270-278页

作者： Liuqingqing Yang Tiancheng Pu Feixiang Tian Yulian He Minghui zhu State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China University of Michigan-Shanghai Jiao Tong University Joint Institute Shanghai Jiao Tong UniversityShanghai 200240China School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

The CO_(2)catalytic hydrogenation represents a promising approach for gas-phase CO_(2)utilization in a direct *** to its excellent hydrogenation ability,nickel has been widely studied and has shown good activities in CO_(2)hydrogenation reactions,in addition to its high availability and low ***,Ni-based catalysts are prone to sintering under elevated temperatures,leading to unstable catalytic *** the present study,various characterization techniques were employed to study the structural evolution of Ni/SiO_(2)during CO_(2)*** anti-sintering phenomenon is observed for both 9%Ni/SiO_(2)and 1%Ni/SiO_(2)during CO_(2)hydrogenation at 400℃.Results revealed that Ni species were re-dispersed into smaller-sized nanoparticles and formed Ni^(0)active *** interestingly,this anti-sintering phenomenon leads to distinct outcomes for two catalysts,with a gradual increase in both reactivity and CH_(4)selectivity for 9%Ni/SiO_(2)presumably due to the formation of abundant surface Ni°from redispersion,while an apparent decreasing trend of CH_(4)selectivity for 1%Ni/SiO_(2)sample,presumably due to the formation of ultra-small nanoparticles that diffuse and partially filled the mesoporous pores of the silica support over ***,the redispersion phenomenon was found relevant to the H_(2)gas in the reaction environment and enhanced as the H_(2)concentration *** finding is believed to provide in-depth insights into the structural evolution of Ni-based catalysts and product selectivity control in CO_(2)hydrogenation reactions.

关键词： Carbon dioxide utilization CO_(2)hydrogenation Nickel-based catalysts Anti-sintering Structural evolution

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Flow field and convective heat transfer of smallscale Taylor-Couette flow induced by end leakage

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Chinese Journal of Aeronautics 2023年第11期36卷 71-90页

作者： Jingyang ZHANG Zhaokun MA Yuan LIU Guiping zhu Yuanwei LYU College of Astronautics Nanjing University of Aeronautics and AstronauticsNanjing 210016China

More and more researchers have paid attention to Taylor-Couette flow whose axial dimension is much larger than other ***,featured by the limited axial length of the bearing,its flow field and convective heat transfer between the rotator and the stator are highly conglutinated with the leakage at the end of the *** investigation was conducted on the flow field and convective heat transfer of small-scale Taylor-Couette flow induced by end leakage through means of numerical simulation and experimental *** static pressure and temperature of the stator were captured by a micromanometer and a time-resolved infrared camera,*** Eddy Simulation(LES)was performed to reveal the instantaneous and mean flow field of the shearing *** show that the flow field and convective heat transfer are tightly associated with the presence of end *** approaching the end of the clearance,the flow is dominated by the axial flow induced by the end leakage,and then a series of Taylor vortices gradually distorts and tilts as moving *** the angular direction,the maximum and minimum static pressures take place near minimum clearance height,*** static pressure along the angular direction and the axial velocity near the minimum clearance height as well as the Nusselt number increase with increases of the rotational Reynolds number and the eccentricity ratio while decreasing with an increase of the dimensionless clearance *** natural convection by buoyancy and forced convection by the shearing flow play a significant role in convective heat *** with classic Taylor-Couette flow,the occurrence of leakage decreases the maximum static pressure while increasing the minimum static *** formation and evolution of the Taylor vortex are dominated by the axial flow.

关键词： End leakage Experimental measurement Large eddy simulation Limited length Taylor-Couette flow Taylor vortex

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