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Spectral energy distributions for TeV blazars

Research in Astronomy and Astrophysics 2018年第10期18卷 19-32页

作者： chao Lin jun-Hui Fan Center for Astrophysics Guangzhou UniversityGuangzhou 510006China Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province Guangzhou 510006China

In this work, we collected a sample of 69 TeV blazars from TeVCat, obtained their multi-wavelength observations, and fitted their spectral energy distributions by using a second degree poly-nomial function. The structure parameters of synchrotron bumps for 68 blazars and those of inverse- Compton bumps for 56 blazars were derived. Then, we conducted statistical analysis on the parame-ters （curvature, peak frequency, peak luminosity, bolometric luminosity and X/γ-ray spectral indexes）. From our analysis and discussions, we can conclude the following：（1） There is a clear positive correla-tion between the synchrotron peak frequency, log （Vp）^s, and the inverse-Compton peak frequency, log （Vp）^IC, and between the synchrotron peak luminosity, log （Vp）^sL（Vp）^s, and the inverse-Compton peak luminosity,log（Vp）^IC L（Vp）^IC. （2） The correlation between the peak frequency and the curvature of synchrotron bump is clearly different from that of the inverse-Compton bump, which further indicates that there are differ-ent emission mechanisms between them. （3） There is a correlation between log （Vp）^IC and γ-ray spectral index, αγ, for the TeV blazars： log （Vp）^IC = -（4.59 ± 0.30）αγ ＋（32.67 ±0.59）, which is consistent with previous work. （4） An ＂L-shape＂ relation is found between log（Vp）^s Up and αx for both TeV blazars and Fermi blazars. A significant correlation between log（Vp）^s and X-ray photon index （αx） is found for the TeV blazars with high synchrotron peak frequency： log（Vp）^s = -（3.20 ± 0.34）αx ＋（24.33 ± 0.79）, while the correlation is positive for low synchrotron peaked TeV sources. （5） In the αx -αγ diagram, there is also an ＂L-shape.＂ The anti-correlation is consistent with results available in the literature, and we also find a positive correlation between them. （6） Inverse-Compton dominant sources have luminous bolometric luminosities.

关键词： galaxies active - BL Lacertae objects general - quasars general - galaxies jets

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Cooling Rates of PREP Ti48Al Alloy

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Journal of Materials Science & Technology 2001年第1期17卷 91-92页

作者： Xuezhu MA jun SHEN Xiumei qi jun JIA School of Materials Science&Engineering Harbin institute of TechnologyHarbin 150001China

Determining the cooling rate of a rapidly-solidified (RS) technique subjectively is a prerequisite of knowing the RS technique, and it is difficult. Model of heat transfer is constructed in this paper in order to calculate cooling rates of rapidly-solidified Ti48AI alloy. Rapid solidification technique utilized is the plasma rotating electrode process (PREP hereafter). The results show that: the cooling rate of PREP is at the scope of 102-103 K/s.

关键词： cooling rate electrode process heat transfer RS technique in order

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Multiscale architectures boosting thermoelectric performance of copper sulfide compound

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Rare Metals 2021年第8期40卷 2017-2025页

作者： Xin-qi Chen Sheng-Jie Fan chao Han Tian Wu Lian-jun Wang Wan Jiang Wei Dai Jian-Ping Yang School of Physics and Mechanical and Electrical Engineering Hubei Engineering Technology Research Center of Environmental Purification MaterialsInstitute of Materials Research and EngineeringHubei University of EducationWuhan430205China State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai201620China Institute for Superconducting and Electronic Materials University of WollongongNorth WollongongNSW2500Australia

Owing to their high performance and earth abundance,copper sulfides(Cu_(2-x)S)have attracted wide attention as a promising medium-temperature thermoelectric *** and grain-boundary engineering are explored to tune the electrical transport and phonon scattering of Cu_(2-x)S based on the liquid-like copper *** multiscale architecture-engineered Cu_(2-x)S are fabricated by a room-temperature wet chemical synthesis combining mechanical mixing and spark plasma *** observed electrical conductivity in the multiscale architecture-engineered Cu_(2-x)S is four times as much as that of the Cu_(2-x)S sample at 800 K,which is attributed to the potential energy filtering effect at the new grain ***,the multiscale architecture in the sintered Cu_(2-x)S increases phonon scattering and results in a reduced lattice thermal conductivity of 0.2 W·m^(-1)·K^(-1) and figure of merit(zT)of 1.0 at 800 *** a zT value is one of the record values in copper sulfide produced by chemical *** results suggest that the introduction of nanostructure and formation of new interface are effective strategies for the enhancement of thermoelectric material properties.

关键词： Thermoelectric properties Copper sulfides Room-temperature synthesis Nanostructure Semiconductor

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Synthesis of 2,4-Diarylcyclooctenopyridines with One-pot Four-component Reactions

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Chemical Research in Chinese Universities 2009年第3期25卷 338-342页

作者： WANG qi-fang YAN chao-guo College of Chemistry ＆ Chemical Engineering Yangzhou University Yangzhou 225002 P. R. China

An efficient one-pot four-component reaction has been developed for the synthesis of 2,4-diarylcyclooctenopyridines, in moderate yields. This route is an effective modified two-step synthesis of Krohnke pyridine and involves a four-component tandem reaction of pyridinium bromide with aromatic aldehydes and cyclooctanone in a system of NHaOAc/HOAc under microwave irradiation.

关键词： Pyridine Cycloalkenopyridine Multicomponent reaction Microwave irradiation

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A multifunctional electrolyte with highly-coordinated solvation structure-in-nonsolvent for rechargeable lithium batteries

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Journal of Energy Chemistry 2020年第12期29卷 362-377页

作者： Hui Zhao Jjinlei Gu Yuliang Gao qian Hou Zengying Ren Yaqin qi Kun Zhang chao Shen jun Zhang Keyu Xie State Key Laboratory of Solidifcation Processing.Center for Nano Energy Materials School of Materials Science and Engineering.Northwesterm Polytechnical University and Shaanxi Joint Laboratory of Graphene(NPU)Xi'an 710072.ShaanxiChina

Rechargeable lithium-based battery is hailed as next-generation high-energy-density battery ***, growth of lithium dendrites, shuttle effect of lithium polysulfides intermediates and unstable interphase of high-voltage intercalation-type cathodes largely prevent their practical ***, to fully conquer the three challenges via one strategy, a novel electrolyte with highlycoordinated solvation structure-in-nonsolvent is designed. On account of the particular electrolyte structure, the shuttle effect is completely suppressed by quasi-solid conversion of S species in Li-S batteries,with a stable cycle performance even at lean electrolyte(5μL mg^(-1)). Simultaneously, in-situ-formed highly-fluorinated interphases can not only lower Li+diffusion barrier to ensure uniform nucleation of Li but also improve stability of NCM cathodes, which enable excellent capacity retention of Lik LiNi(0.5)Co(0.2)Mn(0.3)O2 batteries under conditions toward practical applications(high loading of 2.7 m Ah cm^(-2) and lean electrolyte of 5 m L Ah^(-1)). Besides, the electrolyte is also nonflammable. This electrolyte structure offers useful guidelines for the design of novel organic electrolytes for practical lithium-based batteries.

关键词： Li-S battery Li dendrite High voltage Highly-coordinated solvation structure-in-nonsolvent Nonflammable electrolyte

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Understanding the spatial interaction of ultrasounds based on three-dimensional dual-frequency ultrasonic field numerical simulation

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China Foundry 2024年第1期21卷 29-43页

作者： Zhao-yang Yin qi-chi Le Yan-chao Jiang Da-zhi Zhao qi-yu Liao qi Zou Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China

A transient 3D model was established to investigate the effect of spatial interaction of ultrasounds on the dual-frequency ultrasonic field in magnesium alloy *** effects of insertion depth and tip shape of the ultrasonic rods,input pressures and their ratio on the acoustic field distribution were discussed in ***,the spacing,angle,and insertion depth of two ultrasonic rods significantly affect the interaction between distinct *** a result,various acoustic pressure distributions and cavitation regions are *** spherical rods mitigate the longitudinal and transversal attenuation of acoustic pressure and expand the cavitation volume by 53.7%and 31.7%,respectively,compared to the plate and conical *** the input pressure will enlarge the cavitation region but has no effect on the acoustic pressure distribution *** acoustic pressure ratio significantly affects the pressure distribution and the cavitation region,and the best cavitation effect is obtained at the ratio of 2:1(P15:P20).

关键词： dual-frequency ultrasonic numerical model acoustic pressure spatial interaction magnesium alloy

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Precision measurement of the Newtonian gravitational constant

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National Science Review 2020年第12期7卷 1803-1817页

作者： chao Xue Jian-Ping Liu qing Li jun-Fei Wu Shan-qing Yang qi Liu Cheng-Gang Shao Liang-Cheng Tu Zhong-Kun Hu jun Luo Tian qin Research Center for Gravitational Physics & School of Physics and Astronomy Sun Yat-sen University(Zhuhai Campus) MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics PGMF and School of PhysicsHuazhong University of Science and Technology

The Newtonian gravitational constant G,which is one of the most important fundamental physical constants in nature,plays a significant role in the fields of theoretical physics,geophysics,astrophysics and *** G was the first physical constant to be introduced in the history of science,it is considered to be one of the most difficult to measure accurately so *** the past two decades,eleven precision measurements of the gravitational constant have been performed,and the latest recommended value for G published by the Committee on Data for Science and Technology(CODATA) is(6.674 08 ±0.000 31) × 10m~3 kgswith a relative uncertainty of 47 parts per *** uncertainty is the smallest compared with previous CODATA recommended values of G;however,it remains a relatively large uncertainty among other fundamental physical *** this paper we briefly review the history of the G measurement,and introduce eleven values of G adopted in CODATA 2014 after 2000 and our latest two values published in 2018 using two independent methods.

关键词： precision measurement Newtonian gravitational constant CODATA

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Local solvability of the k-Hessian equations

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Science China Mathematics 2016年第9期59卷 1753-1768页

作者： TIAN GuJi WANG qi XU chao-Jiang Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences The School of Statistics and Mathematics Zhongnan University of Economics and Law School of Mathematics and Statistics Wuhan University Laboratoire de Math'ematiques CNRS UMR 6085 Universite de Rouen

We give a classification of second-order polynomial solutions for the homogeneous k-Hessian equation σ_k[u] = 0. There are only two classes of polynomial solutions: One is convex polynomial; another one must not be(k + 1)-convex, and in the second case, the k-Hessian equations are uniformly elliptic with respect to that solution. Based on this classification, we obtain the existence of C∞local solution for nonhomogeneous term f without sign assumptions.

关键词： k-Hessian equations local solution uniform ellipticity implicit function theorem

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Demetallation of organometallic and metal-mediated reactions

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The Innovation 2022年第4期3卷 19-21页

作者： chao-jun Li Department of Chemistry and FQRNT Centre for Green Chemistry and Catalysis McGill University801 Sherbrooke Street WestMontrealQC H3A0B8Canada

The use of stoichiometric organometallic reagents and stoichiometric metals formed the basis of vast majority of classical reactions for constructing carbon–carbon *** indispensable requirement of stoichiometric metals for such reactions constitutes significant challenges in terms of resource sustainability,operational safety,and chemical-waste *** recent developments in C–H functionalizations,hydrogenative alkene/alkyne addition to electrophiles,the hydrazone umpolung chemistry,and other emerging fields such as the electrosynthesis and photoredox chemistry provide potential solutions to overcome these inherent challenges.

关键词： chemistry bonds overcome

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A new type of triptycene-based stationary phases with alkylated benzimidazolium cations for gas chromatographic separations

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Chinese Chemical Letters 2019年第7期30卷 1415-1418页

作者： jun He Meiling qi Key Laboratory of Cluster Science Ministry of Education of China School of Chemistry and Chemical EngineeringAnalysis & Testing Center Beijing Institute of Technology

Favorable physicochemical properties and unique molecular recognition capability endow triptycenebased materials with good potential as stationary phases for gas chromatography (GC). This work reports a new type of triptycene-based materials functionalized by three benzimidazolium cations with different peripheral alkyl lengths (denoted as TP-3Bim-5C and TP-3Bim-12C) and their GC separation performance. As a result, they shared high resolving performance for the naphthalene isomers but differed for the benzene derivatives with varying polarity. Moreover, their capillary columns exhibited good repeatability and thermal stability. This work presents a facile strategy for tailoring the selectivity of the TP-based stationary phases and demonstrates their promising future for chromatographic analysis.

关键词： Triptycene-based materials Benzimidazolium cation Gas chromatography Stationary phase Separation performance

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