检索结果-南通市图书馆

Communications in Theoretical Physics 2014年第9期61卷 315-319页

作者：尤源陆法林孙东升陈昌远 School of Physics and Electronics Yancheng Teachers University

Using an improved approximate formula to the centrifugal term, we present arbitrary l-state scattering solutions of the hyperbolic potential. The approximate analytical formula of scattering phase shifts and normalized wavefunctions are presented. All data calculated by the above approximate analytical formula are compared with those obtained by using the numerical integration method in the scattering state cases. We find that this improved approximate formula is better than previous one since the calculated results are in good agreement with those exact ones.

关键词： hyperbolic potential scattering solutions analytical approximations

Shock Wave Solution for a Class of Nonlocal Nonlinear Singularly Perturbed Boundary Value Problems with Turning Point

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2015年第3期31卷 701-706页

作者： Xiang-lin HAN Wan-tao LIN Zeng-ji DU Jia-qi MO Huzhou Teachers College State Key Laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamic Institute of Atmospheric Physics Chinese Academy of Sciences School of Mathematical sciences Xuzhou Normal University Department of Mathematics Anhui Normal University

The nonlocal nonlinear boundary value problem with turning point is considered. Leading the stretched variables the formal asymptotic solution of the original problem is constructed. And by using the theory of differential inequalities the existence and uniformly validity of solution for the original boundary value problems are proved. The contribution of this paper is that, the asymptotic behavior of solution is studied by using a simple and special method.

关键词： turning point nonlocal nonlinear singular perturbation shock wave

Adaptive switching frequency buck DC-DC converter with high-accuracy on-chip current sensor

在线全文

学校读者我要写书评

暂无评论

Journal of Semiconductors 2015年第5期36卷 111-119页

作者：江金光黄飞熊智慧 Global Navigation Satellite System Research Center Wuhan University

A current-mode PWM buck DC-DC converter is proposed. With the high-accuracy on-chip current sen- sor, the switching frequency can be selected automatically according to load requirements. This method improves efficiency and obtains an excellent transient response. The high accuracy of the current sensor is achieved by a simple switch technique without an amplifier. This has the direct benefit of reducing power dissipation and die size. Additionally, a novel soft-start circuit is presented to avoid the inrush current at the starting up state. Finally, this DC-DC converter is fabricated with the 0.5μm standard CMOS process. The chip occupies 3.38 mm2. The accuracy of the proposed current sensor can achieve 99.5% @ 200 mA. Experimental results show that the peak efficiency is 91.8%. The input voltage ranges from 5 to 18 V, while a 2 A load current can be obtained.

关键词： DC-DC switching frequency current sensor soft-start wide load range

Teleportation of N-Particle Entangled GHZ State via Entanglement Swapping

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2006年第4X期46卷 595-598页

作者： SHA Jin-Qiao FANG Jian-Xing ZHU Shi-Qun JIANG Wei-Xing QIAN Xue-Min School of Physical science and Technology Suzhou University Suzhou 215006 China

In this scheme, N non-maximally entangled particle pairs are used as quantum channel to teleport an unknown N-particle entangled GHZ state via entanglement swapping. In order to realize this teleportation, the sender Alice operates Bell-state measurement on particles belonging to herself. Then she informs the results to the receiver Bob through classical communication. According to the results, Bob operates corresponding transformation to reconstruct the initial state. The advantage of this scheme is that it needs only one common unitary matrix for Alice＇s different results, which has a more general meaning. As a special case, teleporting an unknown three-particle entangled GHZ state is proposed.

关键词： quantum teleportation N-particle entangled GHZ state entanglement swapping

Effect of thermo-mechanical treatment on mechanical and elastic properties of Ti–36Nb–5Zr alloy

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2015年第3期25卷 229-235页

作者： Qingkun Meng Qing Liu Shun Guo Yongqi Zhu Xinqing Zhao School of Materials science and Engineering Beihang University Institute for Advanced Materials Jiangsu University Division of science and Technology Information General Research Institute for Nonferrous Metals

The evolutions of phase constitutions and mechanical properties of a β-phase Ti–36Nb–5Zr(wt%) alloy during thermo-mechanical treatment were investigated. The alloy consisted of dual(β t α″) phase and exhibited a double yielding phenomenon in solution treated state. After cold rolling and subsequent annealing at 698 K for 20 min, an excellent combination of high strength(833 MPa) and low modulus(46 GPa) was obtained. The high strength can be attributed to high density of dislocations, nanosized α phase and grain refinement. On the other hand, the low Young’s modulus originates from the suppression of chemical stabilization of β phase during annealing, which guarantees the low β-phase stability. Furthermore, the single-crystal elastic constants of the annealed Ti–36Nb–5Zr alloy were extracted from polycrystalline alloy using an in-situ synchrotron X-ray technique. The results indicated that the low shear modulus C44 contributes to the low Young’s modulus for the Ti–36Nb–5Zr alloy, suggesting that reducing C44 through thermo-mechanical treatment might be an efficient approach to realize low Young’s modulus in β-phase Ti alloys. The results achieved in this study could be helpful to elucidate the origin of low modulus and sheds light on developing novel biomedical Ti alloys with both low modulus and high strength.

关键词： Biomedical Ti alloys Martensitic transformation Young’s modulus Elastic constants

Super-High Initial Velocity Mechanism of Bullet Propulsion with Adaptive Pressure-Maintaining Chamber

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Beijing Institute of Technology 2020年第1期29卷 23-28页

作者： Junbo Xiao Hongqiang Li Zhenqiang Liao Ming Qiu Jie Song School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China

To deal with the problem that the initial velocity of the bullet is difficult to increase,the research on the super-high initial velocity propulsion in the barrel weapon with an adaptive pressure-maintaining chamber are *** the law of gun-powder burning and the flow characteristics of gun-powder gas in multi-chamber,the scheme of super-high initial velocity propulsion with an adaptive pressure-maintaining chamber is designed,the ballistic model of the barrel weapon with super-high velocity bullet propulsion is *** research results show that the technical scheme can greatly increase the initial velocity of the bullet with the peak pressure keeping nearly the same as the tradition barrel *** research results can provide a theoretical foundation to significantly increase the initial velocity in barrel weapons using solid propellants,and have an important reference value to comprehensively increase the power of the barrel weapons.

关键词： inner trajectory adaptive pressure-maintaining chamber super-high initial velocity propulsion barrel weapon

Thermal Properties of K(Y_(1-x)Yb_x)(WO_4)_2(x=0.098,0.196,0.294) Crystal

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2010年第1期29卷 109-113页

作者：唐丽永王国富 School of Material science & Engineering Jiangsu University State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterThe Chinese Academy of Sciences

Thermal properties of pure KY（WO4）2 and K（Y1-xYbx）（WO4）2（x=0.098,0.196,0.294） crystals were *** specific heat and thermal diffusivity of crystals were calculated at a range of 50～300 ℃.The calculated result shows that the specific heat and thermal diffusivity of K（Y1-xYbx）（WO4）2（x=0.098,0.196,0.294） crystals were slightly affected by the Yb3＋ *** thermal expansion coefficient of K（Y0.804Yb0.196）（WO4）2 crystals along x,y and z axes were determined to be 13.51,4.474 and 16.60×10-6 K^-1,respectively. These results suggest the K（Y1-xYbx）（WrO4）2 （x = 0.098, 0.196, 0.294） crystal as a laser crystal of low-middle power.

关键词： tungstates thermal conductivity thermal expansion

Environmentally Friendly and Multifunctional Shaddock Peel-Based Carbon Aerogel for Thermal-Insulation and Microwave Absorption

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2021年第7期13卷 28-41页

作者： Weihua Gu Jiaqi Sheng Qianqian Huang Gehuan Wang Jiabin Chen Guangbin Ji College of Materials science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016People’s Republic of China Shenyang Aircraft Design Institute Yangzhou Collaborative Innovation Research Institute Co. LtdShenyang 225002People’s Republic of China

Eco-friendly electromagnetic wave absorbing materials with excellent thermal infrared stealth property,heat-insulating ability and compression resistance are highly attractive in practical *** the aforesaid requirements simultaneously is a formidable ***,ultra-light carbon aerogels were fabricated via fresh shaddock peel by facile freeze-drying method and calcination process,forming porous network *** the heating platform temperature of 70℃,the upper surface temperatures of the as-prepared carbon aerogel present a slow upward *** color of the sample surface in thermal infrared images is similar to that of the *** the maximum compressive stress of 2.435 kPa,the carbon aerogels can provide favorable *** shaddock peel-based carbon aerogels possess the minimum reflection loss value(RLmin)of−29.50 dB in X ***,the effective absorption bandwidth covers 5.80 GHz at a relatively thin thickness of only 1.7 *** the detection theta of 0°,the maximum radar cross-sectional(RCS)reduction values of 16.28 dB m^(2) can be *** simulations of RCS have aroused extensive interest owing to their ingenious design and time-saving *** work paves the way for preparing multi-functional microwave absorbers derived from biomass raw materials under the guidance of RCS simulations.

关键词： Microwave absorption Thermal insulation Carbon aerogel Radar cross-sectional simulation Multi-function

Stabilizing nickel sulfide nanoparticles with an ultrathin carbon layer for improved cycling performance in sodium ion batteries

在线全文

学校读者我要写书评

暂无评论

Nano Research 2016年第10期9卷 3162-3170页

作者： Feipeng Zhao Qiufang Gong Brian Traynor Duo Zhang Jiaojiao Li Hualin Ye Fengjiao Chen Na Han Yeyun Wang Xuhui Sun Yanguang Li Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Soochow University Suzhou 215123 China Departments of Physics and Chemistry Trinity College University of Dublin Dublin 2 Ireland

Nanostructured metal sulfides are potential electrode materials for sodium-ion batteries; however, they typically suffer from very poor cycling stability due to large volume changes and dissolution of discharge products. Herein we propose a rational material design strategy for sulfide-based materials to address these problems. Taking nickel sulfide （NiSx） as an example, we demonstrated that its electrochemical performance can be dramatically improved by confining the NiSx nanoparticles in a percolating conductive carbon nanotube network, and stabilizing them with an ultrathin carbon coating layer. The carbon layer serves as a physical barrier to alleviate the effects of both the volume change and dissolution of active materials. The hybrid material exhibited a large reversible specific capacity of 〉500 mAh/g and excellent cycling stability over 200 cycles. Given the traditionally problematic nature of NiSx as a battery anode material, we believe that the observed high performance reported here reflects the effectiveness of our material design strategy.

关键词： metal sulfides sodium-ion batteries composite carbon coating layer cycling stability

Hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets as an efficient bifunctional catalyst for Zn–air battery

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

Journal of Energy Chemistry 2019年第6期28卷 59-66页

作者： Yuhui Tian Li Xu Jian Bao Junchao Qian Huaneng Su Huaming Li Haidong Gu Cheng Yan Henan Li School of Chemistry and Chemical Engineering Institute for Energy ResearchJiangsu UniversityZhenjiang 212013JiangsuChina jiangsu Key Laboratory for Environment Functional Materials School of Environmental Science and EngineeringSuzhou University of Science and TechnologySuzhou 215009JiangsuChina School of Chemistry Physics and Mechanical EngineeringQueensland University of TechnologyBrisbaneQLD 4001Australia

Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets(Co/N-Pg) is fabricated for Zn–air batteries. A lowcost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn–air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap(0.81 V at 50 mA cm^-2) and high peak power density(119 mW cm^-2) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn–air battery.

关键词： Zn-air batteries Oxygen reduction reaction Oxygen evolution reaction Nitrogen-doped carbon nanosheets Cobalt oxides