检索结果-南通市图书馆

Enhanced multiple anchoring and catalytic conversion of polysulfides by SnO_(2)-decorated MoS_(2) hollow microspheres for high-performance lithium-sulfur batteries

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第5期100卷 216-223页

作者： Yun Tian Zhengyu Wei Fan li Songjie li lixiang Shao Mengyuan He Panfei Sun yuanyuan li School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education Zhengzhou UniversityZhengzhou 450001China

lithium-Sulfur(li-S)batteries are very competitive in energy storage equipment due to their high theoretical capacity and low cost of raw ***,the serious polysulfide"shuttle effect",volume expansion effect and slow conversion reaction kinetics of li-S batteries during the charge/discharge cycle process still need to be resolved ***,we prepared a novel sulfur host of SnO_(2)-decorated MoS_(2) hollow microspheres(SnO_(2)-MoS_(2) HMSs).The unique hollow structure provides enough space to accommodate a large amount of sulfur and effectively adapts to its large volume expansion during charge and discharge *** the other hand,the SnO_(2) nanoparticles that attached to the surface of the MoS_(2) nanosheets will accelerate the catalysis of MoS_(2) and enhance the bonding strength with the polysulfide intermediates through the S-Sn-O chemical bond,which further inhibits the shuttle *** newly synthesized SnO_(2)-MoS_(2) HMSs cathode has achieved excellent electrochemical *** initial discharge specific capacity of 1326.4 mAh g^(-1) was obtained at 0.2 C,and after 100 cycles,the specific capacity of the SnO_(2)-MoS_(2) HMSs/S cathode only decreased slightly to 1183.8 mAh g^(-1),its capacity retention rate reaching as high as 89.2%.We expect the newly synthesized hollow structured MoS_(2) with SnO_(2) decoration provides a new strategy for the construction of li-S battery cathode materials.

关键词： li-S batteries SnO_(2)-decorated hollow MoS_(2)microspheres S-Sn-O chemical bond Electrochemical performance

Fabrication of Iron-base Alloy by Spark Plasma Sintering

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2006年第2期22卷 257-260页

作者： yuanyuan li Xiaoqiang li Yah LONG Wei XIA Min ZHU Weiping CHEN College of Mechanical Engineering South China University of Technology Guazngzhou 510640 China

Fe-2Cu-2Ni-1Mo-0.8C （wt pct） elemental mixed powders were rapidly sintered within 6 min by spark plasma sintering, and the effects of sintering parameters on the densification degree and performance of the assintered materials were investigated. Results showed that when a proper combination of pulse electric current and constant electric current was employed for sintering, the density and bend strength of the as-sintered material reached the maxima, being 7.61×10^3 kg/m^3 and 1540 MPa, respectively. Its corresponding fracture morphology was characterized as the mix of ductile, intergranular and cleavage fractures.

关键词： Spark plasma sintering Iron-base alloy Density Microstructure and performance

Recent research progress for upconversion assisted dye-sensitized solar cells

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2021年第6期32卷 1834-1846页

作者： Xugeng Guo Wenpeng Wu yuanyuan li Jinglai Zhang li Wang Hans Ågren Institute of Upconversion Nanoscale Materials College of Chemistry and Chemical EngineeringHenan UniversityKaifeng 475004China Henan Center for Outstanding Overseas Scientists Henan UniversityKaifeng 475004China Department of Physics and Astronomy Uppsala UniversityBox 516SE-75120 UppsalaSweden

Upconversion(UC)technology makes it possible to harvest infrared(IR)light from the sun and has increasingly been employed in recent years to improve the efficiency of solar *** progress in the area concerns both research on fundamental principles and processes of UC and technologies of device *** increase of important solar cell parameters,like short-circuit photocurrent density and open-circuit photovoltage as well as the total photon-to-current efficiency,has been *** here review the research published during the last few years in the area,in particular we consider the two most cherished techniques,namely the incorporation of upconverting nanophosphors directly into the photoanodes of the solar cells and the introduction of plasmonic metal nanoparticles co-existing with the UC *** ways to achieve strong field enhancement,and the use of the non-linear nature of UC,is to apply microlenses,with or without assisting plasmonic *** enhanced UC action has been demonstrated by broad band and effective harvesting by organic IR antennas,with subsequent mediation by an intermediate nanoshell of the energy into the upconverting ***,nanohybrid and layer-by-layer technologies involving upconverting particles as well as the use of upconverting nanoparticles in hole-transport and electrolyte layers,tested in recent works,are also *** most of these technologies employ upconverting rare earth metals for sequential photon absorption,the main alternative technique,namely triplet-triplet annihilation UC using organic materials,is also *** is our belief that all these approaches will be further much researched in the near future,with potentially great impact on solar cell technology.

关键词： Upconversion nanoparticles Dye-sensitized solar cells Infrared light Triplet-triplet annihilation Photovoltaic systems

Permeable Steel and Its Application in Plastic-injection Mould

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2010年第3期23卷 312-316页

作者： ZHOU Zhaoyao CAO Wenjiong WU Zhengqiang YU Minqiang li yuanyuan School of Mechanical and Automotive Engineering South China University of Technology Guangzhou 510640 China

The gas in plastics mould has great influence on performance, appearance and lifespan of the injection molded parts. Venting channel and its appendix system should be used for gas exhausting in general. However, the dependence on the venting system complicates the mould design. Furthermore in certain condition, it is difficult to integrate the venting system into the mould. Currently a kind of mold material which has gas permeability has been developed in abroad, but the applications of this mold material were restricted by its higher cost and smaller size. In this research, a porous material which was made by powder metallurgy was applied to plastic mould to replace the venting system. Permeability of the steel with different secondary processing was tested and compared with a special apparatus. The metallographic samples of the steel with different secondary processing were prepared and investigated. Finally an actual injection set was established to investigate the applications of permeable steel. The metallographies indicate that the micro-holes inside permeable steel were interconnected. Moulds made of permeable steel exhibit good permeability in the plastic-injection experiments and gas generated in the mould cavity was smoothly exhausted. The melted plastic did not penetrate into the mould or block in the micro-holes. After several times of plastic-injection experiments, the mould still retained good permeability. The strength of this permeable steel is between 200–250 MPa and suitable for industrial applications. The venting systems simplified by permeable steel in plastic-injection have simple structures, which can be applied into any place that requires gas exhausting.

关键词： powder metallurgy permeable steel plastic-injection mould venting system

Numerical Simulation of Upsetting a Cubic Sintered Iron Powder Compact

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2003年第Z1期19卷 141-143页

作者： Wei XIA Puqing CHEN Zhaoyao ZHOU Weibin ZHAO yuanyuan li College of Mechanical Engineering South China University of Technology Guangzhou 510640 China College of Mechanical Engineering South China University of Technology Guangzhou 510640 China College of Mechanical Engineering South China University of Technology Guangzhou 510640 China College of Mechanical Engineering South China University of Technology Guangzhou 510640 China College of Mechanical Engineering South China University of Technology Guangzhou 510640 China

This paper establishes a mechanical model for sintered powder metal material and simulates the material *** metal specimens were compacted, sintered and upset. Relative density and contour of the specimen were measured. The force displacement relationship during upsetting was recorded. The same upsetting process was simulated with 3-dimensional finite element method. In simulation, the cubic specimen was treated as a piece of metal embedded with pores. Its overall relative density was controlled via adjusting the concentration of the *** the virtual upsetting process, when the pores are compressed, material around the pores will be in touch with each other. This kind of self-contact effect was dealt with direct contact detecting method. Classical V. Mises principle and isotropic hardening rule were applied on the material. Simulation results agree with experimental.

关键词： Metal powder, Porous material, FEM

Max-plus-linear model-based predictive control for constrained hybrid systems: linear programming solution

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

控制理论与应用（英文版） 2007年第1期5卷 71-76页

作者： yuanyuan ZOU Shaoyuan li Institute of Automation Shanghai Jiao Tong University Shanghai 200240 China

In this paper, a linear programming method is proposed to solve model predictive control for a class of hybrid systems. Firstly, using the （max, ＋） algebra, a typical subclass of hybrid systems called max-plus-linear （MPL） systems is obtained. And then, model predictive control （MPC） framework is extended to MPL systems. In general, the nonlinear optimization approach or extended linear complementarity problem （ELCP） were applied to solve the MPL-MPC optimization problem. A new optimization method based on canonical forms for max-min-plus-scaling （MMPS） functions （using the operations maximization, minimization, addition and scalar multiplication） with linear constraints on the inputs is presented. The proposed approach consists in solving several linear programming problems and is more efficient than nonlinear optimization. The validity of the algorithm is illustrated by an example.

关键词： Hybrid systems Max-plus-linear systems Model predictive control Canonical form Max-min-plus- scaling function linear programming

Structural view of the regulatory subunit of aspartate kinase from Mycobacterium tuberculosis

在线全文

学校读者我要写书评

暂无评论

Protein & Cell 2011年第9期2卷 745-754页

作者： Qingzhu Yang Kun Yu liming Yan yuanyuan li Cheng Chen Xuemei li National Laboratory of Biomacromolecules Institute of BiophysicsChinese Academy of SciencesBeijing 100101China Structural Biology Laboratory Tsinghua UniversityBeijing 100084China

The aspartate kinase(AK)from Mycobacterium tuberculosis(Mtb)catalyzes the biosynthesis of aspartate family amino acids,including lysine,threonine,isoleucine and *** determined the crystal structures of the regulatory subunit of aspartate kinase from Mtb alone(referred to as MtbAKβ)and in complex with threonine(referred to as MtbAKβ-Thr)at resolutions of 2.6A and 2.0Å,***β is composed of two perpendicular non-equivalent ACT domains[aspartate kinase,chorismate mutase,and TyrA(prephenate dehydrogenase)]per *** ACT domain contains two α helices and four antiparallel β *** structure of MtbAKβ shares high similarity with the regulatory subunit of the aspartate kinase from Corynebacterium glutamicum(referred to as CgAKβ),suggesting similar regulatory *** assays in our study showed that MtbAK is inhibited by *** on crystal structure analysis,we discuss the regulatory mechanism of MtbAK.

关键词： Mycobacterium tuberculosis aspartate kinase crystal structure βsubunit

Research progress on gel polymer electrolytes for lithium-sulfur batteries

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2021年第5期30卷 420-437页

作者： Jie Qian Biyu Jin yuanyuan li Xiaoli Zhan Yang Hou Qinghua Zhang College of Chemical and Biological Engineering Zhejiang UniversityHangzhou 310027ZhejiangChina Institute of Zhejiang University-Quzhou Quzhou 324000ZhejiangChina

lithium-sulfur(li-S)batteries have become a promising candidate for advanced energy storage system owing to low cost and high theoretical specific *** the last decade,in pursuit of li-S batteries with enhanced safety and energy density,the investigation on the electrolytes has leaped form liquid organic electrolytes to solid polymer ***,such solid-state li-S battery system is greatly limited by unfavorable ionic conductivity,poor interfacial contact and narrow electrochemical windows on account of the absence of any liquid *** address these issues,gel polymer electrolytes(GPEs),the incorporation of liquid electrolytes into solid polymer matrixes,have been newly *** the excellent ionic transport and low interfacial resistance provided by GPEs have prompted numerous researchers to make certain progress on high-performance li-S coins,a comprehensive review on GPEs for li-S batteries remains ***,this review focuses on recent development and progress on GPEs in view of their physical and chemical properties for the applications in li-S *** on the components including solid hosts,liquid solutions and fillers of GPEs are systematically summarized with particular emphasis on the relationship between components and ***,current challenges and directional outlook for fabricating GPEs-based li-S batteries with outstanding performance are outlined.

关键词： lithium-sulfur batteries Gel polymer electrolytes Solid hosts liquid solutions

Parametric study on contact sensors for MASW measurement-based interfacial debonding detection for SCCS

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2024年第2期23卷 331-344页

作者： Chen Hongbing Pang Xin Gan Shiyu li yuanyuan Gokarna Chalise Nie Xin Research Institute of Urbanization and Urban Safety School of Civil and Resource EngineeringUniversity of Science and Technology BeijingBeijing 100083China Department of Civil Engineering Tsinghua UniversityBeijing 100084China Faculty of Infrastructure Engineering Dalian University of TechnologyDalian 116081China

Steel-concrete composite structures(SCCS)have been widely used as primary load-bearing components in large-scale civil *** the basis of the co-working ability of steel plate and concrete,the bonding status plays an essential role in guaranteeing the structural performance of ***,efficient non-destructive testing(NDT)on interfacial debondings in SCCS has become a prominent research ***-channel analysis of surface waves(MASW)has been validated as an effective NDT technique for interfacial debonding detection for ***,the feasibility of MASW must be validated using experimental *** study establishes a high-frequency data synchronous acquisition system with 32 channels to perform comparative verification experiments in ***,the current sensing approaches for high-frequency vibration and stress waves are ***,three types of contact sensors,namely,piezoelectric lead-zirconate-titanate(PZT)patches,accelerometers,and ultrasonic transducers,are selected for MASW ***,the selection and optimization of the force hammer head are *** experiments are carried out for the optimal selection of ultrasonic transducers,PZT patches,and accelerometers for MASW *** addition,the influence of different pasting methods on the output signal of the sensor array is *** results indicate that optimized PZT patches,acceleration sensors,and ultrasonic transducers can provide efficient data acquisition for MASW-based non-destructive *** research findings in this study lay a solid foundation for analyzing the recognition accuracy of contact MASW measurement using different sensor arrays.

关键词： steel-concrete composite structures(SCCS) interface debonding detection multi-channel analysis of surface waves(MASW) sensor selection comparative experimental study