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On the Physical Processes in Contact binary Systems

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Chinese Journal of Astronomy and Astrophysics 2007年第2期7卷 235-244页

作者： Run-Qian Huang Han-Feng Song Shao-Lan bi National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming 650011 Graduate University of Chinese Academy of Sciences Beijing 100049

Three important physical processes occurring in contact binary systems are studied. The first one is the effect of spin, orbital rotation and tide on the structure of the components, which includes also the effect of meridian circulation on the mixing of the chemical elements in the components. The second one is the mass and energy exchange between the components. To describe the energy exchange, a new approach is introduced based on the understanding that the exchange is due to the release of the potential, kinetic and thermal energy of the exchanged mass. The third is the loss of mass and angular momentum through the outer Lagrangian point. The rate of mass loss and the angular momentum carded away by the lost mass are discussed. To show the effects of these processes, we follow the evolution of a binary system consisting of a 12m⊙ and a 5m⊙ star with mass exchange between the components and mass loss via the outer Lagrangian point, both with and without considering the effects of rotation and tide. The result shows that the effect of rotation and tide advances the start of the semi-detached and the contact phases, and delays the end of the hydrogen-burning phase of the primary. Furthermore, it can change not only the occurrence of mass and angular momentum loss via the outer Lagrangian point, but also the contact or semi-contact status of the system. Thus, this effect can result in the special phenomenon of short-term variations occurring over a slow increase of the orbital period. The occurrence of mass and angular momentum loss via the outer Lagrangian point can affect the orbital period of the system significantly, but this process can be influenced, even suppressed out by the effect of rotation and tide. The mass and energy exchange occurs in the common envelope. The net result of the mass exchange process is a mass transfer from the primary to the secondary during the whole contact phase.

关键词： stars binaries general - stars mass-loss - stars evolution

microstructure and nano-mechanical property of cold spray Co-base refractory alloy coating

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Acta metallurgica Sinica(English Letters) 2011年第3期24卷 190-194页

作者： Vongli LIANG bi SHI Xiaoping YANG Junbao ZHANG Xianming mENG Advanced Technology Institute Baosteel Technology Center Baoshan Iron & Steel Co. Shanghai 201900 China School of materials Science and Engineering Dalian University of Technology Dalian 116024 China

Co-base refractory alloy coating was prepared on carbon steel substrate by cold spray technology; microstructure and nano-mechenieal property were examined by scanning electron microscope （SEm） and nano indenter individually. The results showed that about 250 μm Co-base refractory alloy coating could be deposited o11 steel substrate by cold spray technique, interface between coating and substrate was combined well, and the refractory alloy particle had a significant plastic deformation during deposition process; mixing Ni powders into Co-base refractory alloy powders could increase the density and decrease the nano-hardness of coating, the nano-hardness and elastic modulus of refractory alloy coating was higher than 6 GPa and 160 GPa, respectively.

关键词： Cold spray Co-base refractory alloy microstructure Nano-mechanical property

Holographic technicolor model and dark matter

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Chinese Physics C 2020年第9期44卷 16-24页

作者： Yidian Chen Xiao-Jun bi mei Huang Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Physics University of Chinese Academy of SciencesBeijing 100049China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

We investigate the strongly coupled minimal walking technicolor model(mWT)in the framework of a bottom-up holographic model,where the global SU(4)symmetry breaks into SO(4)*** the holographic model,we found that 125 GeV composite Higgs particles and small Peskin–Takeuchi S parameter can be achieved *** addition,the model predicts a large number of particles at the TeV scale,including dark matter candidates Technicolor Interacting massive Particles(TImPs).If we consider the dark matter nuclear spin-independent cross-section in the range of 10^−45∼10^−48cm^2,which can be detected by future experiments,the mass range of TImPs predicted by the holographic technicolor model is 2∼4 TeV.

关键词： dark matter holography technicolor

microstructure of TiB Whisker Reinforced Ti matrix Composite

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Journal of materials Science & Technology 1997年第1期13卷 41-44页

作者： Lu, YX Li, DX Ping, DH bi, J ma, ZY Institute of metal Research Chinese Academy of Sciences Shenyang 110015 China

The composite of Ti matrix with TiB whisker reinforcement has been successfully fabricated. The content of TiB whisker in Ti matrix can reach about 30 vol. pet. metallographic examination, morphology and microstructure of TiB whisker, interface structure between TiB whisker and Ti matrix were investigated using optical microscope, SEm, TEm and HREm technology. The diameter distribution of TiB whisker is from 0.1 mu m to 3.5 mu m and the aspect ratio of TiB whisker is from 10 to 20. The cross-section of whisker is generally polygon. Because of good compatibility between TiB whisker and Ti matrix it is identified that there is no obvious interaction of Ti matrix with TiB reinforcement and TiB whisker reinforced Ti matrix composites have excellent elevated properties.

关键词： Fiber reinforced materials

Responses of soil stoichiometry and soil enzyme activities in the different distance around opencast coal mine of the Hulun Buir Grassland of China

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International Journal of Coal Science & Technology 2024年第1期11卷 221-231页

作者： Yinli bi Nan Guo Yanxu Zhang Xianglei Li Ziheng Song State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources China University of Mining and Technology(Beijing)Beijing100083China Institute of Ecological Environment Restoration in mine Areas of West China Xi’an University of Science and TechnologyXi’an710054China

The objectives of this study were to explore the changes in soil stoichiometry and enzyme activities at different distances from an opencast coal mine in the Hulun Buir Grassland of China. Four transects were established on north and east sides of the opencast coal mining area, and samples were collected at 50 m, 550 m, and 1550 m from the pit on each transect. Control samples were collected from a grassland station 8 km from the opencast coal mining area that was not disturbed by mining. Four replicate soil samples were collected at each point on the four transects. Soil physicochemical properties and enzyme activities were determined, and correlations between soil properties and stoichiometric ratios and enzyme activities were explored using redundancy analysis. The increase in distance from mining did not significantly affect soil properties, although soil urease activity was significantly lower than that of the control area. Soil properties 1550 m from the mine pit were similar to those at the grassland control. In addition, soil total nitrogen had the greatest effect on soil stoichiometry, and soil total potassium had the greatest effect on soil enzyme activities. Coal dust from opencast mining might be the main factor affecting soil stoichiometry and enzyme activities. The results of this study provide direction for the next step in studying the influence of mining areas on soil properties and processes.

关键词： Opencast coal mine Soil stoichiometry Soil enzyme activities Distance Grassland

Concatenated Alamouti codes using multi-level modulation and symbol mapping diversity technique

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Frontiers of Electrical and Electronic Engineering in China 2010年第4期5卷 464-469页

作者： mingwei CAO Guangguo bi China Ship Research and Development Academy Beijing 100192China National mobile Communications Research Laboratory Southeast UniversityNanjing 210096China

A family of space-time block codes(STBCs)for systems with even transmit antennas and any number of receive antennas is *** new codeword matrix is constructed by concatenating Alamouti space-time codes to form a block diagonal matrix,and its dimension is equal to the number of transmit *** Alamouti codes in the same codeword matrix have the same information;thus,full transmit diversity can be achieved over fading *** improve the spectral efficiency,multi-level modulations such as multi-quadrature amplitude modulation(m-QAm)are *** symbol mapping diversity is then exploited between transmissions of the same information from different antennas to improve the bit error rate(BER)*** proposed codes outperform the diagonal algebraic space-time(DAST)codes presented by Damen[Damen et *** Transactions on Information Theory,2002,48(3):628–636]when they have the same spectral ***,they outperform the 1/2-rate codes from complex orthogonal ***,compared to DAST codes,the proposed codes have a low decoding complexity because we only need to perform linear processing to achieve single-symbol maximum-likelihood(mL)decoding.

关键词： space-time block codes(STBCs) symbol mapping spectral efficiency decoding complexity pairwise error probability(PEP)

Influence of rare earth oxides on microstructure and mechanical properties of nickel-based superalloys fabricated by high energy beam processing:A review

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Journal of Rare Earths 2024年第9期42卷 1629-1645,I0001页

作者： Lianjie bi Hua Yan Peilei Zhang Haichuan Shi Zhiyuan Li Ruidi Li School of materials Science and Engineering Shanghai University of Engineering ScienceShanghai201620China College of Agricultural Science and Engineering Hohai UniversityNanjing211100China Department of mechanics and maritime Science Chalmers University of TechnologyGothenburSE41296Sweden State Key Laboratory of Powder metallurgy Central South UniversityChangsha410083China

In this paper,the effects of rare earth oxides on the micro structure and mechanical properties of nickelbased superalloys prepared by high-energy beam processing technology were critically *** focus is on the optimal amount of rare earth oxides that can produce ideal *** attention was paid to their main strengthening mechanisms,including solid solution strengthening mainly in the form of solid solution dissolved in the nickel-based alloy and improving the microstructure of the alloy by grain refinement or fine grain strengthening produced by homogenizing the distribution phase.Y_(2)O_(3),La_(2)O_(3) and CeO_(2) rare earth oxides can also improve the fluidity of the alloy molten pool and reduce the segregation of alloying *** advantages can significantly improve the mechanical properties of the ***,this paper outlines the future research directions of rare earth oxides,aiming to expand their application potential.

关键词： Rare earths High energy beam Nickel-based superalloys microstructure mechanical properties

Covalent Organic Frameworks with trans-Dimensionally Vinylene-linked π-Conjugated motifs

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Chemical Research in Chinese Universities 2022年第2期38卷 382-395页

作者： bi Shuai mENG Fancheng ZHANG Zixing WU Dongqing ZHANG Fan School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240P.R.China

Vinylene-linked covalent organic frameworks(COFs) are a class of promising porous organic materials that feature fully π-conjugated structures, high crystallinity, permanent porosity, ultrahigh chemical stability, and extraordinary optoelectronic properties. Over the past 5 years, this kind of material has been witnessed rapid development either in chemical synthesis or in potential applications. In this review, we summarize the chemistry to synthesize vinylene-linked COFs, especially the synthetic strategies involving activation of aryl methyl groups for condensation reaction. We then scrutinize the state-of-the-art development in properties and functions of this kind of COFs. Our own opinions on the further development of the vinylene-linked COFs are also presented for discussion.

关键词： Covalent organic framework(COF) Vinylene linkage Stability π-Conjugated structure Semiconducting property

Progress in Organic Solar Cells: materials, Physics and Device Engineering

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Chinese Journal of Chemistry 2021年第9期39卷 2607-2625页

作者： Pengqing bi Shaoqing Zhang Jingwen Wang Junzhen Ren Jianhui Hou State Key Laboratory of Polymer Physics and Chemistry Beijing National Laboratory for MolecularSciences CAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemistry and biology Engineering University of Science and Technology BeijingBeijing 100083China University of Chinese Academy of Sciences Beijing 100049China

Organic solar cells(OSCs)have been developed for few decades since the preparation of the first photovoltaic device,and the record power conversion efficiency(PCE)certified by national renewable energy laboratory(NREL)has exceeded 17%.Looking back the whole history of OSCs,its rapid development is inseparable from multi-disciplinary efforts,including the new materials synthesizing,the device physics,and the device engineering,especially the breakthroughs in these *** this review,we are aiming at reviewing the history of the development of OSCs and summarizing the representative breakthroughs.

关键词： Energy conversion Organic solar cells materials science Photophysics Device engineering