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Reaction mechanism of self-propagating magnesiothermic reduction of ZrB_2 powders

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Rare Metals 2013年第4期32卷 408-413页

作者： Yong-Ting Zheng hong-bo li Zhong-Hai Xu Jing Zhao Pan Yang Science and Technology on Advanced Composites in Special Environments Laboratory Harbin Institute of Technology Materials Engineering Department North China Institute of Aerospace Engineering

Fine zirconium diboride （ZrB2） powders with high purity were successfully prepared by combustion synthesis through magnesiothermic reduction process in Mg-B2O3-ZrO2 system. The reaction mechanism was investigated by differential thermal analysis and quenching experiment. The results show that the whole magnesio-thermic reduction process includes three stages： first, molten B2O3 and Mg formed above the temperature of 650 ℃, and glassy B2O3 and solid ZrO2 particles were coated on the surface of the molten Mg; thus, the hollow balls can be formed when the molten Mg was exuded under capillary function. Second, ZrO2 particles reacted with molten Mg to form Zr and MgO with dissolution-precip-itation mechanism, which released a large amount of heat to induce the diffusion reaction between B203 and Mg to form B and MgO. Last, Zr reacted with B to form ZrB2 grains. The preparation of ZrB2 by self-propagating syn-thesis in Mg-B2O3-ZrO2 system is a solid-liquid-liquid reaction.

关键词： Reaction mechanism Magnesiothermicreduction Zirconium boride Self-propagating synthesis

Dimesitylborylphenyl substituted 1,3,4-oxadiazole:Synthesis,characterization and sensitivity to F^-

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Chinese Chemical Letters 2011年第5期22卷 599-602页

作者： Xiang hong li bo Xu, Kang Le Lv Ai Qing Zhang College of Chemistry and Materials South-Central University for Nationalities Wuhan 430074 China

A new 1,3,4-oxadiazole compound with a dimesitylboryl group was synthesized and characterized by ~1H NMR,MS,element analysis and X-ray single-crystal *** exhibits good blue emission at 425 nm and high sensitivity to f... 详细信息

关键词： 1 3.4-Oxadiazole Dimesitylboryl Fluoride anion Chemo-sensor

Microwave-assisted convenient synthesis of N-arylpyrrolidines in water

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Chinese Chemical Letters 2011年第3期22卷 276-279页

作者： hong bo li Wu liang Lang liu Kai Chen Yi Wu College of Material Science and Engineering Southwest University of Science and Technology Mianyang 621010 China

An efficient and clean synthesis of N-arylpyrrolidines from arylamines and 1,4-dimesyloxybutane was developed using microwave irradiation in an aqueous potassium carbonate medium without any *** procedure is rapid,sim... 详细信息

关键词： N-Arylpyrrolidine Arylamine 1 4-Dimesyloxybutane Microwave

Theoretical Studies on Structures and Properties of Endohedral Fullerenes Complexes: XH_n@C_(32)(X=F, O, N, C; n=1―4)

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Chemical Research in Chinese Universities 2008年第2期24卷 220-222页

作者： CHANG Ying-fei hong bo SUN li-li TANG Shu-wei WANG Rong-shun Institute of Functional Material Chemistry Faculty of Chemistry Northeast Normal University Changchun 130024 P R. China

Theoretical studies on structures and properties of endohedral fullerene complexes formed by encapsulating small molecules of HF, H20, NH3, and CH4 in a C32 fullerene cage, were carried out by ab initio method. Current calculations reveal that these processes to encase them in fullerene are energetically unfavorable because of the small cavity size of C32. The red shift in the F-H stretching frequency indicates the potential existence of hydrogen bonding between the HF molecule and the carbon cage.

关键词： Endohedral fullerene C32 Ab initio Stretching frequency Hydrogen bonding

Highly electronegative PtAu alloy for simultaneous hydrogen generation and ethanol upgrading

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Rare Metals 2023年第9期42卷 2949-2956页

作者： Kun Yin Meng-Gang li Yu-Guang Chao Yin Zhou Shao-Jun Guo Fang-Ze liu hong-bo li Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing100081China School of Materials Science and Engineering Peking UniversityBeijing100871China Advanced Research Institute of Multidisciplinary Sciences Beijing Institute of TechnologyBeijing100081China

Simultaneous electrochemical synthesis of high-valueadded chemicals and hydrogen is a promising technology for efficient carbon utilization and renewable energy storage. However, the lack of rational guidance for desi... 详细信息

关键词： hydrogen alloy hinder

Weak absorption test and defect analysis of optical coatings

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光学精密工程 2005年第4期13卷 430-434页

作者： HE hong-bo li Xia FAN Shu-hai ZHAO Yuan-an SHAO Jian-da FAN Zheng-xiu Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China

Surface thermal lensing technique was developed into a high-sensitive apparatus for weak absorption test and defect analysis of optical coatings. A continuous-wave 1 064 nm Nd:YAG laser and a He-Ne laser were employed as pump source and probe source, respectively. Low noise photoelectrical components and a lock-in amplifier were used for photo-thermal deformation signal detection. In order to improve sensitivity, the apparatus configuration was optimized by choosing appropriate parameters, including pump beam spot size, chopper frequency, detection distance, waist radius and position of probe beam. Coating samples were mounted on a x-y stage. Different procedures, such as single spot, linear scan and 2-dimension area scan, could be performed manually or automatically. Various optical coatings were prepared by both electron beam evaporation and ion beam sputtering deposition. High sensitivity was obtained and low to 1×10 -7 weak absorption was tested in low-loss coating samples. For the sensitivity extreme of the system, 1×10 -8 absorption was reason out to be measured by surface thermal lensing technique. Very small standard deviation was achieved for the reproducibility evaluation. Moreover, a spatial resolution of 25 micron was proved according to the area scan which traced out the profile of photo-thermal defects inside optical coatings. The system was employed in the analyses of optical absorption, absorption uniformity and defect characterization, and revealed the relationship between laser-induced damage and absorption of optical coatings.

关键词：光学涂覆技术吸收能力稳定性激光技术

Comparison of the Coronal Green-line Intensities with the EUV Measurements from SDO/AIA

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Research in Astronomy and Astrophysics 2022年第7期22卷 191-205页

作者： Xue-Fei Zhang Yu liu Ming-Yu Zhao Ji-hong liu Abouazza Elmhamdi Teng-Fei Song Zi-Han li hong-bo li Fei-Yang Sha Jing-Xing Wang Xiao-bo li Yuan-Deng Shen Shun-Qing liu hong-Fei liang R.M.Al-Shammari Yunnan Observatories Chinese Academy of SciencesKunming 650011China University of Chinese Academy of Sciences Beijing 100049China Shijiazhuang University Shijiazhuang 050035China School of Physical Science and Technology Southwest Jiaotong UniversityChengdu 610031China Department of Physics and Astronomy King Saud UniversityP.O.Box 2455Riyadh 11451Saudi Arabia Yunnan Normal University School of Physics and Electronic InformationKunming 650500China Institute of Space Physics Luoyang Normal UniversityLuoyang 471934China

The intensity of the green line(Fe ⅩⅣ 5303 A) is the strongest in the visible spectrum of the solar corona,and this line has been used as long-term powerful diagnostic tools for studying the coronal configurations and hot plasma ***,it remains unclear and an open question whether there exists close relationship between the green line intensities and the coronal extreme ultraviolet(EUV) line emissions for various coronal *** this paper,we use the green-line data by the lijiang YOGIS Lyot coronagraph and the EUV data from the Solar Dynamics Observatory/Atmospheric Imaging Assembly instruments in order to perform direct comparisons and analyses,based on two algorithms developed to extract particular features in the low *** is found that,among the correlation coefficients obtained between the intensities of 5303 A and the EUV lines,the coefficients between the green line and the 211 A wavelength for different coronal structures and different limb locations always keep the highest values(ranging from 0.89 to 0.99),which has not been reported *** result can be helpful and promising to link together the various physical processes involved at different heights in the corona by precisely tracking the bright loops or other features observed in 5303 A above the limb down to the correct surface locations revealed by the 211 A ***,the ground-based observations of the coronal green line and the space-based EUV observations at 211 A can advantageously complement each other when there is a need.

关键词： Sun:corona Sun:magnetic fields stars:coronae

Dioxygen affinities and catalytic oxidation performance of cobalt(Ⅱ) hydroxamates with benzo-15-crown-5 pendants

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Chinese Chemical Letters 2007年第1期18卷 103-106页

作者： hong bo li Chuan Qin Wen Bing Yang Xiao Ping Hu Sheng Ying Qin College of Material Science and Engineering Southwest University of Science and Technology Mianyang 621010 China Department of Chemistry Sichuan University Chengdu 610064 China

The oxygenation constants （Ko2） of cobalt（Ⅱ） hydroxamates （CoL^1 2-CoL^3 2） with benzo-15-crown-5 （B15C5） pendants were measured over the range of -5 to ＋20 ℃, and the values of thermodynamic parameters （ΔH^0 and ΔS^0） were calculated based on these （Ko2） values, Meanwhile, these crowned complexes were employed to the oxidation for p-xylene to p-toluic acid with air at 110Δ under normal atmospheric pressure. The effects of B15C5 pendant and the length of chain bonded to B15C5 in these complexes on the O2-binding capabilities and oxidation for p-xylene were investigated with the comparison of crown-free analogues CoL^4 2.

关键词： Benzo-15-crown-5 Cobalt(Ⅱ) hydroxamates Dioxygen affinity Catalytic oxidation p-Xylene

Synthesis, crystal structure and thermal analysis of tetraiodo-4,4'-bi-1,2,4-triazole

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Chinese Chemical Letters 2013年第9期24卷 786-788页

作者： Lei li Yu Chi Xiao-Yu Zhang Guang-Quan Zhang Yong Zhang Ting-Xing Zhao Ming Huang hong-bo li School of Materials Science and Engineering Southwest University of Science and Technology Institute of Chemical Materials CAEP

Tetraiodo-4,4＇-bi-l,2,4-triazole （1） was synthesized from a reaction of iodine monochloride witb 4,4＇ bi- 1,2,4-triazole （2）, which was prepared by a transamination reaction between 4-amine-1,2,4-triazole and N,N-dimethylformamide azine dihydrochloride （3） obtained via a Vilsmeier reaction. The title compound was extensively characterized by melting point, elemental analysis, 1R, HRMS and single crystal X-ray diffraction. The single crystal X-ray structural analysis reveals that compound 1 exhibits a stable conformation with the two triazole rings being perpendicular to minimize three-dimensional steric hindrance and stacking through aromatic zr. analysis from TGA and DSC indicates that resnectivelv. Jr packing interactions between molecules. The therma compound I decomposes at 275.40 ℃ and 338.35 C

关键词： Tetraiodo-4 4'-bi- 1 2 4-triazole Synthesis Crystal structure Thermal stability