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Boosting alkaline hydrogen evolution via spontaneous built-in electric field

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Rare Metals 2024年第11期43卷 5848-5859页

作者： Ze-Peng Lv Da-He Zhang Meng-Lu Zang Shao-Long Li Ji-Lin He jian-xun Song Zhongyuan Critical Metals Laboratory Zhengzhou UniversityZhengzhou 450001China Henan Province Industrial Technology Research Institute of Resources and Materials Zhengzhou UniversityZhengzhou 450001China College of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

The electrochemical reaction rate strongly depends on the pH of the solution and the relatively sluggish alkaline hydrogen evolution reaction(HER)process,attributed to alterations in the type of proton donor and binding energy,has consistently presented a significant ***,we report a new method for boosting alkaline HER via spontaneous built-in electric field strategy employed on cobalt phosphide nanofibers(NFs)*** anion-cation dual-introduction of V and N on the NFs not only increases the electrochemical surface area but also enhances the catalytic activity,thereby elevating the performance of alkaline *** investigation strategy combining experiments and calculations revealed the charge transfer law between multiple active components and the enhanced regulation mechanism of alkaline HER process,ultimately achieving a nearly twice increase in reaction overpotential of the as-fabricated catalyst at-10 mA·cm^(-2).This new approach provides a potential strategy for improving the efficiency of core catalyst for energy conversion technologies.

关键词： Multiple active sites Built-in electric felid Chemical substitution Hydrogen Electrocatalyst

The Synthesis of Cyclotriphosphazene Liquid Crystals

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Chinese Chemical Letters 1998年第8期9卷 727-729页

作者： Yong Gang YANG jian xun WEN(Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032) Shanghai Inst. of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China

Four functional cyclotriphosphazene liquid crystals have been synthesized. Their phase transition temperatures have also been measured by polarizing textural observation and confirming by DSC.

关键词： cyclotriphosphazene liquid crystal synthesis

A multiple maneuvering targets tracking algorithm based on a generalized pseudo-Bayesian estimator of first order

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第6期14卷 417-424页

作者： Shi-cang ZHANG jian-xun LI Liang-bin WU Chang-hai SHI School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University Aviation Key Laboratory of Science and Technology on AISSS AVIC Radar and Avionics Institute

We describe the design of a multiple maneuvering targets tracking algorithm under the framework of Gaussian mixture probability hypothesis density(PHD) ***,a variation of the generalized pseudo-Bayesian estimator of first order(VGPB1) is designed to adapt to the Gaussian mixture PHD filter for jump Markov system models(JMS-PHD).The probability of each kinematic model,which is used in the JMS-PHD filter,is updated with *** weighted sum of state,associated covariance,and weights for Gaussian components are then *** and merging techniques are also adopted in this algorithm to increase *** of the proposed algorithm is compared with that of the JMS-PHD ***-Carlo simulation results demonstrate that the optimal subpattern assignment(OSPA) distances of the proposed algorithm are lower than those of the JMS-PHD filter for maneuvering targets tracking.

关键词： Gaussian mixture PHD filter Jump Markov system Generalized pseudo-Bayesian estimator of first order(GPB1) Multi-target tracking

Synchronization of MIMO OFDM systems by perfect complete generalized complementary orthogonal loosely synchronous code groups

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The Journal of China Universities of Posts and Telecommunications 2009年第2期16卷 1-7页

作者： WANG jian YANG xun LI Dao-ben School of Information Engineering,Beijing University of Posts and Telecommunications,Beijing 100876,China School of Information Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

This article proposes a time/frequency synchronization algorithm in the multiple input multiple output （MIMO） systems, in which the perfect complete generalized complementary orthogonal loosely synchronous code groups are used as the synchronization sequence. The synchronization algorithm is divided into four stages： 1） synchronization in time domain by signal autocorrelation; 2） synchronization in frequency domain by fast Fourier transform （FFT）; 3） multipath dissociation using coherent detection and fine time synchronization; 4） fine frequency offset estimation by phase rotation. As per the perfect complete generalized complementary orthogonal loosely synchronous code groups, the cross-correlation and out-of-phase auto-correlation for any relative shift between any two codes is always zero. This ideal property makes the time/frequency synchronization algorithm simple and efficient. The simulation results show that even in the multipath fast fading channel with low signal noise ratio （SNR）, the MIMO system can get synchronized both in the time domain and frequency domain with high stability and reliability.

关键词： MIMO OFDM synchronization complementary orthogonal code loosely synchronous (LS) code

Effect of Electric Potentials on Microstructure, Corrosion and Wear Characteristic of the Nitrided Layer Prepared on 2Cr13 Stainless Steel by Plasma Nitriding

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Acta Metallurgica Sinica(English Letters) 2019年第6期32卷 733-745页

作者： Yang Li Shang-Zhou Zhang jian-xun Qiu Yong-Yong He Jun-Jie Xiu Qian-Wen Ye Zhong-Li Liu School of nuclear equipment and nuclear engineering Yantai University.Yantai 264005China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China

Plasma nitriding is a widely used technology to enhance the surface performance and extend the service life of alloy *** current research mainly focuses on the influences of time,temperature,gas type and pressure parameters on nitriding behavior,while fewer studies have been conducted on the electric *** paper mainly reports the effect of the electric potential on nitriding *** conditions were set using cathodic,anodic and floating potentials in a plasma nitriding furnace.2Cr13 stainless steel was nitrided at 450°C for 5h in an NH3 *** experimental results show that the nitriding treatment can be well performed under the different electric potentials,but differences exist in microstructures,morphologies and performance results of the modified *** thickness and hardness values of the nitrided layer are ranked as follows:cathodic[anodic[floating *** anodic nitrided surface has an obvious particle deposition layer composed of nitrides and *** and tribological experiments show that the corrosion resistance and wear resistance were significantly improved after a nitriding treatment using the three electric ***,the floating nitriding treatment resulted in the best tribological performance and corrosion resistance.

关键词： Nitriding Stainless steel Wear Corrosion

Effect of cooling rate on microstructure and inclusion in non-quenched and tempered steel during horizontal directional solidification

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Journal of Iron and Steel Research International 2019年第9期26卷 973-982页

作者： Hui Liu Zong-ze Huang Da-jiang Yu De-lin Hu Hong-gang Zhong Qi-jie Zhai jian-xun Fu State Key Laboratory of Advanced Special Steel School of Materials Science and EngineeringShanghai UniversityShanghai 200072China State Key Laboratory of Development and Application Technology of Automotive Steels (Baosteel Group) Shanghai 201900China

In order to investigate the relationship between microstructure and MnS inclusion in non-quenched and tempered steel, and cooling rate during horizontal directional solidification, 49MnVS steel was used to conduct the experiments with a selfdesigned device. The mathematical effect of cooling rate on dendritic arm spacing and mean diameter of MnS particles (dMnS) were determined by using linear regression method. The results show that the length of dendrite from solid–liquid interface to end-solidification decreased with increasing the withdrawal velocity (#). dMnS has a similar value in the area of the steady directional solidification;the value of dMnS was 4.1, 3.6, 3.3, 2.8 and 2.3 lm at withdrawal velocity of 50, 75, 100, 150 and 200 lm/s, respectively. dMnS increased with reducing # or RC (interface cooling rate). MnS precipitated in the gaps between dendrites and was influenced by secondary dendritic arm spacing. Besides, a new concept of the ‘Precipitation Unit Space’(PUS) was proposed and the relationships between dMnS, VPUS (volume of PUS) and RC were obtained.

关键词： Horizontal directional solidification Dendrite MnS Inclusion Cooling rate

High Temperature Superconductivity in the Past Twenty Years Part 2——Towards to Practical Applications

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Journal of Electronic Science and Technology of China 2008年第2期6卷 237-254页

作者： jian-xun Jin The Center of Applied Superconductivity and Electrical Engineering University of Electronic Science and Technology of China Chengdu 610054 China

After discovering high temperature superconducting materials 20 years ago, the preparation of applicable HTS materials has been pursued along with HTS mechanism and characteristic study. At present, the focus on the applied HTS technology has been moving to the industrial preparations from the laboratory research stage, and the technology has been well verified for practical applications from small to large scales. The fabrication techniques of engineering HTS materials are being industrialized; and various HTS devices are also on the way towards practical applications. This paper provides a comprehensive summary on the applied high temperature superconductivity with regard to various applicable HTS materials, their preparation techniques and charac- terization, and applications in a wide range.

关键词： High temperature superconductors(HTS) HTS applications strong current applications,critical currents magnetic fields.

High Temperature Superconductivity in the Past Twenty Years Part 1——Discovery, Material, and Theory

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Journal of Electronic Science and Technology of China 2008年第2期6卷 225-236页

作者： jian-xun Jin The Center of Applied Superconductivity and Electrical Engineering University of Electronic Science and Technology of China Chengdu 610054 China

Twenty years after the discovery of hightemperature superconductors （HTSs）, the HTS materials now have been well developed. Meanwhile the mechanism of superconductivity is still one of the topical interests in physics. The achievements made on HTS materials and theories during the last twenty years are reviewed comprehensively in this paper.

关键词： High temperature superconductivity,high temperature superconductor high temperaturesuperconducting theory

Features and Prototypes of HTS High Q Resonant Circuit

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Journal of Electronic Science and Technology of China 2007年第2期5卷 130-135页

作者： jian-xun Jin The Center of Applied Superconductivity and Electrical Engineering University of Electronic Science and Technology of China （UESTC） Chengdu 610054 China

High Te superconductor （HTS） technology has been used to develop a unique high Q resonant circuit. Such circuit or device has some special characteristics such as very high voltage generation. Theoretical study and experimental approaches have proceeded for the concept verification. This paper presents the theory about this high Q resonant circuit. The operation principle of the circuit is described. A practical prototype for HTS high voltage generation is also demonstrated. The experiment result shows that very high voltages can be achieved by the developed method using HTS technology.

关键词： Electronic resonant circuit high Q inductor high Tc superconductor high voltage power electronic switch.