Exceptional electrochemical performance of freestanding electrospun carbon nanofiber anodes containing ultrafine SnO_<i>x</i> particles

Zhang, Biao,Yu, Yang,Huang, Zhendong,He, Yan-Bing,Jang, Donghyuk,Yoon, Won-Sub,Mai, Yiu-Wing,Kang, Feiyu,Kim, Jang-Kyo The Royal Society of Chemistry 2012 ENERGY AND ENVIRONMENTAL SCIENCE Vol.5 No.12

<P>SnO<SUB><I>x</I></SUB>–carbon nanofiber (CNF) composites are synthesized using the electrospinning technique for use as freestanding electrodes in Li-ion batteries. The electrodes made from the composites carbonized at 750 °C (SnO<SUB><I>x</I></SUB>–CNF-750) with 14.5 wt% SnO<SUB><I>x</I></SUB> deliver a remarkable capacity of 674 mA h g<SUP>−1</SUP> after 100 cycles when discharged at 0.5 A g<SUP>−1</SUP>. This result is considered the highest among those reported in the literature for anodes made from similar electrospun carbon fibers containing SnO<SUB><I>x</I></SUB> nanoparticles. An increase in carbonization temperature to 950 °C (SnO<SUB><I>x</I></SUB>–CNF-950) results in a significant reduction of the particle content in the fiber due to aggregation of Sn to form nanoparticles external to the fibers, with concomitant degradation of capacities. The presence of amorphous SnO<SUB><I>x</I></SUB> particles at the atomic scale embedded in the conductive CNFs is thought to be responsible for the exceptional electrochemical performance of the SnO<SUB><I>x</I></SUB>–CNF-750 electrodes. These ultrafine particles facilitate the reaction Sn + <I>x</I>Li<SUB>2</SUB>O → SnO<SUB><I>x</I></SUB> + 2<I>x</I>Li<SUP>+</SUP> + 2<I>x</I>e<SUP>−</SUP>, making it highly reversible, which is confirmed by the growing peak currents with increasing scan rate indicated by cyclic voltammetry, and the absence of Sn–Sn bonds in the particles revealed by the extended X-ray absorption fine structure spectroscopy (EXAFS). Both the SnO<SUB><I>x</I></SUB> particle size and content in the fiber play important roles in controlling the rate and cyclic performance of the SnO<SUB><I>x</I></SUB>–CNF composite electrodes.</P> <P>Graphic Abstract</P><P>This paper presents novel SnO<SUB><I>x</I></SUB>–carbon nanofiber composites with embedded ultrafine SnO<SUB><I>x</I></SUB> particles. The composites deliver remarkable power/energy densities as well as excellent cyclic performance due to their high reversibility and stability. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2ee23145j'> </P>

Performance Evaluation and Shear Resistance of Modular Prefabricated Two-Side Connected Composite Shear Walls

Can Mei,Zhendong Zhao,Yongshan Zhang,Dayang Wang,Chengqing Wu 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.8

This paper investigates the impact of configuration parameters on the seismic performance of the modular prefabricated two-side connected composite shear wall. Firstly, the finite element model of the modular prefabricated two-side connected composite shear wall was established and validated by Xu’s experimental results. Secondly, three aspects of parameter investigationswere discussed in detail based on the validated numerical technology, namely the design parameter of ISP, design parameter of the stud, and design parameter of reinforced concrete faceplate (RCF). Then, the computation formula of shear capacity is deduced on the basis of the finite element model for reference to structural design. The results of parameter analysis displayed that the seismic performance of the modular prefabricated two-side connected composite shear wall has excellent seismic performance with the array studs of the length-diameter ratio of 4 which the center distance of 150 mm, and RCF with the thickness of 75 mm. A satisfactory but unadventurous estimation of the shear capacity of a modular prefabricated two-side connected composite shear wall is supplied by the advised technique.

Geometry of Elytra Opening and Closing in Some Beetles (Coleoptera, Polyphaga)

Leonid Frantsevich,Zhendong Dai,Wei Ying Wang,Yafeng Zhang 한국응용곤충학회 2005 한국응용곤충학회 학술대회논문집 Vol.2005 No.05

Parameter identification of the phenomenological model for magnetorheological fluid dampers using hierarchic enhanced particle swarm optimization

Jin Guo,Zhendong Li,Mengxuan Zhang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.3

The magnetorheological (MR) fluid damper, as a new generation of highperformance and intelligent vibration damping devices for engineering structures, has broad application prospects in structural vibration reduction. Nonlinear hysteresis is a complex phenomenon of MR dampers. In this paper, the phenomenological model is used to simulate the dynamics of MR dampers. To accurately and efficiently identify the parameters of the phenomenological model, the hierarchical enhanced particle swarm optimization (HEPSO) algorithm is proposed. This algorithm applies a hierarchical optimization mechanism and introduces media particles to the enhanced PSO (EPSO) algorithm to improve the optimization process of parameter identification and enhance the performance of the PSO algorithm without reducing the possibility of finding the optimal solution. Compared with the standard PSO (SPSO) algorithm and the EPSO algorithm, the HEPSO algorithm has a higher efficiency, accuracy and robustness in identifying a highly nonlinear hysteretic system problem.

Wind resistance performance of a continuous welding stainless steel roof under static ultimate wind loading with testing and simulation methods

DaYang Wang,Zhendong Zhao,Tong Ou,Zhiyong Xin,Mingming Wang,Yongshan Zhang 한국풍공학회 2021 Wind and Structures, An International Journal (WAS Vol.32 No.1

Ultrapure ferritic stainless steel provides a new generation of long-span metal roof systems with continuous welding technology, which exhibits many unknown behaviors during wind excitation. This study focuses on the wind-resistant capacity of a new continuous welding stainless steel roof (CWSSR) system. Full-scale testing on the welding joints and the CWSSR system is performed under uniaxial tension and static ultimate wind uplift loadings, respectively. A finite element model is developed with mesh refinement optimization and is further validated with the testing results, which provides a reliable way of investigating the parameter effect on the wind-induced structural responses, namely, the width and thickness of the roof sheeting and welding height. Research results show that the CWSSR system has predominant wind-resistant performance and can bear an ultimate wind uplift loading of 10.4 kPa without observable failures. The welding joints achieve equivalent mechanical behaviors as those of base material is produced with the current of 65 A. Independent structural responses can be found for the roof sheeting of the CWSSR system, and the maximum displacement appears at the middle of the roof sheeting, while the maximum stress appears at the connection supports between the roof sheeting with a significant stress concentration effect. The responses of the CWSSR system are greatly influenced by the width and thickness of the roof sheeting but are less influenced by the welding height. Ultrapure ferritic stainless steel provides a new generation of long-span metal roof systems with continuous welding technology, which exhibits many unknown behaviors during wind excitation. This study focuses on the wind-resistant capacity of a new continuous welding stainless steel roof (CWSSR) system. Full-scale testing on the welding joints and the CWSSR system is performed under uniaxial tension and static ultimate wind uplift loadings, respectively. A finite element model is developed with mesh refinement optimization and is further validated with the testing results, which provides a reliable way of investigating the parameter effect on the wind-induced structural responses, namely, the width and thickness of the roof sheeting and welding height. Research results show that the CWSSR system has predominant wind-resistant performance and can bear an ultimate wind uplift loading of 10.4 kPa without observable failures. The welding joints achieve equivalent mechanical behaviors as those of base material is produced with the current of 65 A. Independent structural responses can be found for the roof sheeting of the CWSSR system, and the maximum displacement appears at the middle of the roof sheeting, while the maximum stress appears at the connection supports between the roof sheeting with a significant stress concentration effect. The responses of the CWSSR system are greatly influenced by the width and thickness of the roof sheeting but are less influenced by the welding height

Thermo-Mechanical Coupling Analysis of the Actuating Mechanism in a High Speed Press

Jin Cheng,Zhendong Zhou,Yixiong Feng,Zhenyu Liu,Yangyan Zhang 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.5

In order to ensure the manufacturing precision of an ultra-precision high speed press, an integrated thermo-mechanical coupling model of its actuating mechanism is proposed, which includes the mechanical models of the slider and crankshaft, the thermal models for calculating the heat generation powers at different bearings as well as the heat transfer and heat dissipation in the actuating mechanism. The validity of the proposed thermo-mechanical coupling model is verified by a thermal equilibrium experiment when the press operates under the full load of 3000kN at 300 rpm. A sensitivity analysis is conducted to investigate the simulation errors resulting from the variation of the ambient temperature, the results of which demonstrate that the average ambient temperature should be applied for improving simulation accuracy. Then the thermal stiffness of the actuating mechanism and the thermo-mechanical coupling characteristics of different parts are analyzed by the proposed model with the average ambient temperature applied. The influences of the thermally induced loads on the thermal stiffness are discussed in detail. It is concluded that the temperature rise of the actuating mechanism in the stamping process of a high speed press should be fully considered in the design phase for ensuring its manufacturing precision.

DEVELOPMENT OF A COMPOUND POWER-SPLIT HYBRID POWER SYSTEM FOR COMMERCIAL VEHICLES

Qing Li,Zhendong Zhang,Jianyong Bai,Tong Zhang,Fuxiang Gai 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.1

A novel compound power-split hybrid power system based on two planetary gear sets for commercial vehicles is developed. The equivalent lever diagram is used to investigate the components speed and torque characteristics of the system, and then the system dynamic torque control and transmission efficiency are described in equations. Six types of operating modes which are divided into two pure electric modes and four hybrid modes are analyzed by the simplified combined lever diagrams, and their torque decoupling in form of formula is derived. The hybrid transmission (HT) external characteristic is analyzed simultaneously. A control strategy which implements the rule-based (RB) method for the system is depicted. To evaluate the performance of a hybrid vehicle equipped with this hybrid system, the vehicle control and physical models are developed. Then power performance and economic performance simulations are performed. Meanwhile, corresponding tests are carried out to validate simulations. Simulation and test results indicate that, the fuel consumption for C-WTVC of the vehicle equipped with the proposed hybrid system is about 11 L/100 km and it declines by 21 % compared with 14 L/100 km of the traditional vehicle.

Coat colour phenotype of Qingyu pig is associated with polymorphisms of melanocortin receptor 1 gene

Xiaoqian Wu,Zhendong Tan,Linyuan Shen,Qiong Yang,Xiao Cheng,Kun Liao,Lin Bai,Surong Shuai,Mingzhou Li,Xuewei Li,Shunhua Zhang,Li Zhu 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.7

Objective: Qingyu pig, a Chinese indigenous pig breed, exhibits two types of coat colour phenotypes, including pure black and white with black spotting respectively. Melanocortin receptor 1 (MC1R) and agouti signaling protein (ASIP) are two widely reported pivotal genes that significantly affect the regulation of coat colour. The objectives of this study were to investigate whether the polymorphisms of these two genes are associated with coat colour and analyze the molecular mechanism of the coat colour separation in Qingyu pig. Methods: We studied the phenotype segregation and used polymerase chain reaction amplification and Sanger sequencing to investigate the polymorphism of MC1R and ASIP in 121 Qingyu pigs, consisting of 115 black and 6 white with black spotted pigs. Results: Coat colour of Qingyu pig is associated with the polymorphisms of MC1R but not ASIP. We only found 2 haplotypes, EQY and Eqy, based on the 13 observed mutations from MC1R gene. Among which, Eqy presented a recessive inheritance mode in black spotted Qingyu pigs. Further analysis revealed a g.462-463CC insertion that caused a frameshift mutation and a premature stop codon, thus changed the first transmembrane domain completely and lost the remaining six transmembrane domains. Altogether, our results strongly support that the variety of Qingyu pig’s coat colour is related to MC1R. Conclusion: Our findings indicated that black coat colour in Qingyu pig was dominant to white with black spotted phenotype and MC1R gene polymorphism was associated with coat colour separation in Qingyu pig.

Stem Rot on Adzuki Bean (Vigna angularis) Caused by Rhizoctonia solani AG 4 HGI in China

Sun, Suli,Xia, Changjian,Zhang, Jiqing,Duan, Canxing,Wang, Xiaoming,Wu, Xiaofei,Lee, Suk-Ha,Zhu, Zhendong The Korean Society of Plant Pathology 2015 Plant Pathology Journal Vol.31 No.1

During late August and early September 2011, stem rot symptoms were observed on adzuki bean plants (Vigna angularis) growing in fields located in Beijing and Hebei Province, China, respectively. In this study, four isolates were obtained from infected stems of adzuki bean plants. Based on their morphology, and sequence and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses of the ribosomal DNA internal transcribed spacers (rDNA-ITS) region, the four isolates were identified as Rhizoctonia solani in anastomosis group (AG) 4 HGI. Pathogenicity tests showed that all isolates were strongly pathogenic to adzuki bean and resulted in serious wilt symptoms which was similar to observations in the fields. Additionally, the isolates infected several other crops and induced related rot on the roots and basal stems. To our knowledge, this is the first report of Rhizoctonia solani AG 4 HGI causing stem rot on adzuki bean.

Effect of EGR Combined with Intense Tumble Flow on a Well-Calibrated Commercial Turbocharged GDI Engine

Yin Congbo,Pan Hao,Zhang Zhendong,Zhu Haibing,Shen Kai 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.5

A turbocharged GDI engine with variable intake tumble is used to study the effects of EGRcombined with enhanced tumble on the engine’s economy, power, and emissions characteristics. The effects of EGR with enhanced intake tumble flow, on the combustion phase, combustion duration, knock index and combustion cycle variation of the engine, were studied at two speeds of 1500 r/min and 2000 r/min from low to medium and to full load. The research shows that although the commercial engine has been well calibrated and optimized, the optimization of EGR and enhanced tumble flow together with the optimization of the ignition angle can improve the engine’s economy and emission characteristics, while maintaining relatively fast burning speed and low combustion cycle variation. From medium to heavy load, the economy can be improved by 2.6 ~ 10 %, and the minimum fuel consumption can be reduced to 213 g/kW.h (ƞe = 36.8 %). At the same time, the increase of the combustion cycle variation is controlled within 5 %, but as the load and the EGR ratio increase, the power loss cannot be compensated by the advance of the ignition angle. The 6 ~ 21 % EGR ratio brings 3.5 ~ 9 % power loss.