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Study on the tribological properties of metal rolling bearing under lubrication with diketone lubricants

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Science China(Technological Sciences) 2024年第7期67卷 2003-2017页

作者： DU ShaoNan ZHANG ChenHui luo zhi State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China Beijing National Laboratory of Molecular Sciences CAS Key Laboratory of Engineering PlasticsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China

In this article, 1-(4-ethylphenyl)-nonane-1,3-dione(0206) was prepared by Claisen condensation. By mixing 0206, chelate, and base oil in a ratio of 3.2:4.8:2, a diketone lubricant(PAO=14(20%)) that can achieve superlubricity was prepared and applied to bearing lubrication experiments. The experimental results show that when the bearing was lubricated by base oil, the friction coefficient(COF) and temperature rise decreased with the decrease of the viscosity of PAO. When PAO=14(20%) was used as the lubricant, the COF of the bearing was the lowest(0.001), and the wear morphology was comparable to that of the bearing lubricated with commercial lubricant. Compared with the base oil with the same viscosity, it is found that the COF and temperature rise of the bearing lubricated by PAO=14(20%) were lower under any experimental conditions. And when the amount of lubricant added was 10 μL, the COF of the bearing lubricated by PAO=14(20%) reached a very low value(0.0004).Bearing ball surface analysis identified the formation of diketone adsorption films. Combined with the previous PAO=14(20%)superlubricity mechanism, it was considered that the occurrence of tribochemical reaction and the bearing effect of chelates were the main reasons for the existence of ultra-low friction coefficient and low wear. In addition, when there were polar molecules in the lubricant, they were adsorbed on the metal surface through tribochemical reactions, resulting in many irregular pits on the surface.

关键词： superlubricity diketone chelate tribochemical recations bearing lubrication

Medium-Mn steels for hot forming application in the automotive industry

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International Journal of Minerals,Metallurgy and Materials 2021年第5期28卷 741-753页

作者： Shuo-shuo Li Hai-wen luo School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

Advanced high-strength steels have been widely used to improve the crashworthiness and lightweight of *** from the popular cold stamping,hot forming of boron-alloyed manganese steels,such as 22MnB5,could produce ultra-high-strength steel parts without springback and with accurate control of ***,hot-formed medium-Mn steels could have many advantages,including better mechanical properties and lower production cost,over hot-formed *** paper reviews the hot forming process in the automotive industry,hot-formed steel grades,and medium-Mn steel grades and their application in hot forming in *** particular,the adaptabilities of medium-Mn steels and the presently popular 22MnB5 into hot forming were compared *** research should focus on the technological issues encountered in hot forming of medium-Mn steels to promote their commercialization.

关键词： medium-Mn transformation-induced plasticity steel hot forming mechanical properties retained austenite baking

Covert communication with beamforming over MISO channels in the finite blocklength regime

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Science China(Information Sciences) 2021年第9期64卷 187-201页

作者： Xinchun YU Yuan luo wen CHEN School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

This paper considers beamforming techniques for covert communication over multiple input single output(MISO) channels with finite blocklength. We first show that the optimal input distribution for covert communication over complex Gaussian channels is circular symmetric complex Gaussian. By reviewing our previous results on the throughput of Gaussian random coding over additive white Gaussian noise(AWGN) channels, the achievability and converse bounds on the attainable throughput over MISO channels are analyzed. Then, the optimal beamforming strategies and their relationship with the transmitting power are thoroughly investigated in a variety of situations in terms of several types of channel state information available at both ends of the system. We reveal the fact that the maximal allowable transmit power is not constrained by covertness requirement when there is full channel information of the adversary, while there is an upper bound of the transmit power which is based on beamforming and an outage-based covertness criterion if there is only partial channel information of the adversary. Finally, numerical results are presented to show that the throughput of covert communication can be increased notably by adopting a proper beamforming strategy in MISO channels in comparison with the single antenna case.

关键词： beamforming circular symmetric complex Gaussian covert communication MISO channels power control

Properties of Boron-Substituted Heterofullerenes

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Chinese Physics Letters 1998年第2期15卷 106-108页

作者： ZOU Ying luo Min-xing WANG zhi-jian LI wen-zhu Zhejiang Institute of Modern Physics Department of PhysicsZhejiang UniversityHangzhou 310027

On the basis of a succinct description of geometrical configurations for giant fullerenes,the electronic properties and structural distortions of heterofullerenes C_(N-1)B(N=60,180,240,420,540,720,780)are analyzed by the extended Su-Schrieffer-Heeger *** comparison with their pristine fullerenes CN,local distortions and mid-gap states are found to occur in boron-doped giant fullerenes.

关键词： distortion boron fullerenes

Influence of annealing on microstructure and hydrogen storage properties of V48Fe12Ti15Cr25 alloy

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Journal of Iron and Steel Research International 2020年第2期27卷 217-227页

作者： Long luo Xuan Bian wen-yuan Wu Ze-ming Yuan Yong-zhi Li Ting-ting Zhai Feng Hu School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina Analytical and Testing Center Inner Mongolia University of Science and Technology.Baotou 014010Inner MongoliaChina

V48Fe12Ti15Cr25 alloy was prepared using vacuum arc melting and was subsequently annealed for 10 h at 1273 *** effects of annealing on the hydrogen storage properties and microstructure of the V48Fe12Ti15Cr25 alloys were *** results indicated that the alloy consisted of main body-centered cubic,Ti-rich,and TiFe *** annealing,the kinetic properties of the alloy were improved but its hydrogen storage capacity was slightly *** kinetic mechanisms of the hydrogen absorption and desorption of the alloys were *** dehydrogenation enthalpy of the alloy was decreased by 2.57 kJ/mol after *** scanning calorimetry indicated that the hydride decomposition temperature of the annealed alloy was *** hydrogen desorption activation energies of the as-cast and annealed alloys were calculated to be 79.41 and 71.25 kJ/mol,*** results illustrated that annealing was a beneficial method of improving the kinetic and thermodynamic properties of the hydrogen absorption/desorption of the alloy.

关键词： V-based solid solution alloy Annealing Microstructure Hydrogen storage Kinetic mechanism

Gravitational perturbations of the Einstein-Euler-Heisenberg black hole

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Chinese Physics C 2022年第8期46卷 287-300页

作者： zhi luo Jin Li Department of Physics Chongqing UniversityChongqing 401331China

The prospect of using gravitational wave detections via the quasinormal modes(QNMs) to test modified gravity theories is exciting area of current *** waves(GWs) emitted by a perturbed black hole(BH) will decay as a superposition of their QNMs of oscillations at the ringdown *** this work,we investigate the QNMs of the Einstein-Euler-Heisenberg(EEH) BH for both axial and polar gravitational *** obtain master equations with the tetrad formalism,and the quasinormal frequencies of the EEH BH are calculated in the 6 th order wentzel-Kramers-Brill?uin *** is interesting to note that the QNMs of the EEH BH would differ from those of the Reissner-Nordstr?m BH under the EH parameter,which indicates the EH parameter would affect the gravitational perturbations for the EEH BH.

关键词： black hole quasinormal modes gravitational perturbation

Reflected Backward Doubly Stochastic Differential Equations with Discontinuous Coefficients

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Acta Mathematica Sinica,English Series 2013年第4期29卷 639-650页

作者： zhi LI Jiao Wan luo School of Information and Mathematics Yangtze University School of Mathematics and Information Sciences Guangzhou University

In this paper, we study one-dimensional reflected backward doubly stochastic differential equations （RBDSDEs） with one continuous barrier and discontinuous （left or right continuous） genera- tor. We obtain an exis... 详细信息

关键词： Reflected backward doubly stochastic differential equations existence theorem comparison theorem

Linearly Polarized Polarization-Maintaining Er^(3+)-Doped Fluoride Fiber Laser in the Mid-Infrared

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Journal of Electronic Science and Technology 2022年第1期20卷 1-8页

作者： Hong-Yu luo Yong-zhi Wang State Key Laboratory of Electronic Thin Films and Integrated Devices School of Optoelectronic Science and EngineeringUniversity of Electronic Science and Technology of ChinaChengdu 610054

We demonstrated the~2.8-μm and~3.5-μm linearly polarized continuous wave(CW)laser outputs from a polarization-maintaining(PM)Er^(3+)-doped fluoride fiber *** introducing a film polarizer into the cavity to select the laser polarization orientation,the~2.8-μm linearly polarized CW laser with a high polarization extinction ratio(PER)of~23 dB and maximum output power of 2.37 W was achieved under double-end pumping at 976 *** adding another 1981-nm pump source simultaneously,the~3.5-μm linearly polarized CW laser was also obtained,giving higher PER of~27 dB and maximum output power of 307 mW which is only limited by the available power of 1981-nm *** the best of our knowledge,this is the first report on a mid-infrared linearly polarized CW PM fiber laser in the>2.5-μm mid-infrared *** work not only opens up opportunities for some new mid-infrared applications,but also provides a promising platform for developing high-stability and versatile mid-infrared laser sources.

关键词： Fiber laser linearly polarized mid-infrared polarization-maintaining(PM)

Iron-based layered double hydroxide packed with metal-organic frameworks for enhanced overall water-splitting electrocatalysis

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Tungsten 2024年第4期6卷 859-868页

作者： Long Chen Yun luo zhi-Peng Yu Yi-Kun Cheng Yang Zheng Li He Jia-Hao Xiong wen-wen Kong Key Laboratory for Green Process of Chemical Engineering of Xinjiang Bingtuan School of Chemistry and Chemical EngineeringShihezi UniversityShihezi832003China Institute of Scientific Research Luzhou North Chemistry Industry Co.LtdLuzhou646600China International Iberian Nanotechnology Laboratory(INL) Avenida Mestre Jose Veiga4715-330BragaPortugal CAS Key Laboratory of Functional Materials and Devices for Special Environments Xinjiang Key Laboratory of Electronic Information Materials and DevicesCenter of Materials Science and Optoelectronics EngineeringXinjiang Technical Institute of Physics and Chemistry of CASUrumqi830011China

Designing hybrid materials with numerous catalytic active sites,high specific surface area,and interfacial interactions is an effective strategy to improve electrocatalytic *** this work,iron-based metal organic frameworks(Fe-MOFs)@(Co,Ni)Fe-layered double hydroxide(LDH)is successfully constructed using the similar"MOF growing on LDH"strategy for oxygen evolution reaction and hydrogen evolution reaction in the alkaline *** synthesized hybrid materials in this particular way show excellent electrochemical overall water-splitting performance with the cell voltage of 1.62 V at10 mA·cm^(-2) in the alkaline environment due to the optimized adsorption/desorption properties of metal ions on oxygencontaining species and interfacial effects of hybrid ***-MOFs@(Co,Ni)Fe-LDH also exhibits excellent hydrogen and oxygen production efficiency of 370 and 175μL·min^(-1),*** work draws on an effective approach to the fabrication of MOF@LDH structures and provides new insights into overall water-splitting in alkaline conditions.

关键词： Metal-organic frameworks(MOFs) Layered double hydroxide Electrocatalysis Water splitting Interfacial interactions