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WD+RG systems as the progenitors of type Ia supernovae

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Research in Astronomy and Astrophysics 2010年第3期10卷 235-243页

作者： bo wang zhan-Wen Han National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Type Ia supernovae （SNe Ia） play an important role in the study of cosmic evolution, especially in cosmology. There are several progenitor models for SNe Ia proposed in the past years. By considering the effect of accretion disk instability on the evolution of white dwarf （WD） binaries, we performed detailed binary evolution calculations for the WD ＋ red-giant （RG） channel of SNe Ia, in which a carbon--oxygen WD accretes material from a RG star to increase its mass to the Chandrasekhar mass limit. According to these calculations, we mapped out the initial and final parameters for SNe Ia in the orbital period-secondary mass （log Pi_ M2^i） plane for various WD masses for this channel. We discussed the influence of the variation of the duty cycle value on the regions for producing SNe Ia. Similar to previous studies, this work also indicates that the long-period dwarf novae offer possible ways for producing SNe Ia. Meanwhile, we find that the surviving companion stars from this channel have a low mass after the SN explosion, which may provide a means for the formation of the population of single low-mass WDs （〈0.45 M⊙）.

关键词： stars: evolution -- supernovae: general -- binaries: close -- white dwarfs

A likely candidate of type Ia supernova progenitors: the X-ray pulsating companion of the hot subdwarf HD 49798

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Research in Astronomy and Astrophysics 2010年第7期10卷 681-688页

作者： bo wang zhan-Wen Han National Astronomical Observatories / Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

HD 49798 is a hydrogen depleted subdwarf 06 star and has an X-ray pulsating companion （RX J0648.0-4418）. The X-ray pulsating companion is a massive white dwarf. Employing Eggleton＇s stellar evolution code with the optically thick wind assumption, we find that the hot subdwarf HD 49798 and its X-ray pulsating companion could produce a type Ia supernova （SN Ia） in future evolution. This implies that the binary system is a likely candidate of an SN Ia progenitor. We also discuss the possibilities of some other WD ＋ He star systems （e.g. V445 Pup and KPD 1930＋2752） for producing SNe Ia.

关键词： binaries close -- stars individual (HD 49798) -- stars evolution -- supernovae general -- white dwarfs

Novel Evaluation Method of Vehicle Suspension Performance Based on Concept of Wheel Turn Center

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 935-944页

作者： wang bo GUAN Hsin LU Pingping zhan Jun State Key Laboratory of Automobile Simulation and Control Jilin University

The current research of suspension performance evaluation is mixed in the evaluation of vehicle handling and ride comfort. However, it is lack of a direct and independent evaluation method for suspension performance. In this paper, a novel wheel turn center method is proposed to evaluate the suspension performance. This method is based on the concept and application of wheel turn center （WTC） and sprung mass turn center （SPTC）. The vehicle body and each wheel are regarded to be independent rigid bodies and have their own turn centers which reflect respective steering motions and responses. Since the suspension is the link between vehicle body and wheels, the consistence between the sprung mass turn center and the wheel turn center reflects the effect and performance of the suspension system. Firstly, the concept and appropriate calculation method of WTC and SPTC are developed. Then the degree of inconsistence between WTC and SPTC and the time that they achieve consistence, when the vehicle experiences from transient steering to steady steering state, are proposed to evaluate suspension performance. The suspension evaluation tests are conducted under different vehicle velocities and lateral accelerations by using CarSim software. The simulation results show that the inconsistence of steering motion between vehicle body and wheels are mainly at high speeds and low lateral accelerations. Finally, based on the proposed evaluation indexes, the influences of different suspension characteristic parameters on suspension performance and their matches to improve steering coordination are discussed. The proposed wheel turn center method provides a guidance and potential application for suspension evaluation and optimization.

关键词： suspension evaluation wheel turn center sprung mass turn center

A PROXIMAL POINT ALGORITHM FOR A SYSTEM OF GENERALIZED MIXED VARIATIONAL INEQUALITIES

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Journal of Systems Science & Complexity 2012年第5期25卷 964-972页

作者： bo WAN Xuegang zhan Department of Mathematics and Statistics Chongqing Technology and Business University School of Accountancy Chongqing Technology and Business University

This paper introduces and considers a new system of generalized mixed variational inequal- ities in a Hilbert space, which includes many new and known systems of variational inequalities and generalized variational inequalities as special cases. By using the two concepts of η-subdifferential and η-proximal mappings of a proper function, the authors try to demonstrate that the system of generalized mixed variational inequalities is equivalence with a fixed point problem. By applying the equivalence, a new and innovative η-proximal point algorithm for finding approximate solutions of the system of generalized mixed variational inequalities will be suggested and analyzed. The authors also study the convergence analysis of the new iterative method under much weaker conditions. The results can be viewed as a refinement and improvement of the previously known results for variational inequalities.

关键词： Lipschitz continuity proximal point algorithms relaxed (γ τ)-cocoercivity system ofgeneralized mixed variational inequalities.

The mechanisms of thermal solidification agent promoting steam diversion in heavy oil reservoirs

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Petroleum Science 2024年第3期21卷 1902-1914页

作者： zhan-Xi Pang Qian-Hui wang Qiang Meng bo wang Dong Liu State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China Liaohe Oilfield Institute CNPC ChinaPanjin124000LiaoningChina Henan Oilfield Institute Sinopec ChinaNanyang473400HenanChina Tianjin Branch of China National Offshore Oil Company(CNOOC)Ltd. Tianjin300452China

At high cycles of steam huff&puff,oil distribution in reservoirs becomes stronger heterogeneity due to steam *** solidification agent can be used to solve this *** solution is a lowviscosity liquid at normal temperature,but it can be solidified above 80℃.The plugging degree is up to 99%at 250℃.The sweep efficiency reaches 59.2%,which is 7.3%higher than pure steam *** addition,simultaneous injection of viscosity reducer and/or nitrogen foams can further enhance oil *** mechanism of this technology depends on its strong plugging ability,which changes the flowing pattern of steam to effectively mobilize remaining *** reducer and nitrogen foams further expand the sweep range and extends the effective ***,thermal solidification agent can plug steam channeling paths and adjust steam flowing direction to significantly enhance oil recovery at high cycles of steam huff&puff.

关键词： Heavy oil reservoir Steam huff&puff Steam channeling Steam diversion Plugging performance Mechanism analysis

Reanalysis of the Isotopic Mixture of Neutron-Capture Elements in the Metal-Poor Star HD 175305

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Chinese Physics Letters 2012年第1期29卷 299-302页

作者： zhanG Jiang wang bo zhanG bo HAN zhan-Wen National Astronomical Observatories/Yunnan Observatory Chinese Academy of SciencesKunming 650011 Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650011 School of Mathematics and Science Shijiazhuang University of EconomicsShijiazhuang 050016 Department of Physics Hebei Normal UniversityShijiazhuang 050016

The neutron-capture process is traditionally postulated to be responsible for the nucleosynthesis of heavy elements beyond *** on theleast squares method and solar isotopic abundances from the classical model,we estimate the relative contributions of the s- and r-processes to the abundance of neutron-capture elements in the metalpoor star HD 175305 from the component *** the calculated component coefficients C_(r) and C_(s),the model predicts the isotopic fractions of elements Nd,Sm and Eu to be f_(142+144) =0.482,f_(152+154) =0.525 and f_(l51) =0.450,*** well as the observed abundances,the isotropic fractions are also consistent with the ***,for the first time,we estimated the contribution percentage of the two neutron processes (the r- and s-processes) from the observed isotopic fractions of different elements in HD 175305,*** r-process contribution of 67%^(+21%)_(-32%) from the 4604 (A) line of Sm.

关键词： elements Mixture analysis

Modelling and Verification of Real-Time Publish and Subscribe Protocol Using UPPAAL and Simulink/Stateflow

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Journal of Computer Science & Technology 2020年第6期35卷 1324-1342页

作者： Qian-Qian Lin Shu-Ling wang bo-Hua zhan Bin Gu State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijing 100190China Beijing Institute of Control Engineering Beijing 100081China

Real-Time Publish and Subscribe (RTPS) protocol is a protocol for implementing message exchange over an unreliable transport in data distribution service (DDS). Formal modelling and verification of the protocol provide stronger guarantees of its correctness and efficiency than testing alone. In this paper, we build formal models for the RTPS protocol using UPPAAL and Simulink/Stateflow. Modelling using Simulink/Stateflow allows analyzing the protocol through simula-tion, as well as generate executable code. Modelling using UPPAAL allows us to verify properties of the model stated in TCTL (Timed Computation Tree Logic), as well as estimate its performance using statistical model checking. We further describe a procedure for translation from Stateflow to timed automata, where a subset of major features in Stateflow is supported, and prove the soundness statement that the Stateflow model is a refinement of the translated timed automata model. As a consequence, any property in a certain fragment of TCTL that we have verified for the timed automata model in UPPAAL is preserved for the original Stateflow model.

关键词： Real-Time Publish and Subscribe(RTPS) modelling verification UPPAAL Simulink/Stateflow

Strain rate analyses during elliptical vibration cutting of Inconel 718 using finite element analysis,Taguchi method,and ANOVA

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Advances in Manufacturing 2020年第3期8卷 316-330页

作者： Hai-bo Xie Zi-Qing Yang Na Qin zhan-Jiang wang Tribology Research Institute Department of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu610031People’s Republic of China

The high strain rate in metal cutting significantly affects the mechanical properties of the work piece by altering its *** study outlines the material strain rates during elliptical vibration *** finite element analysis,Taguchi method,and analysis of variance(ANOVA)were employed to analyze the effects and contributions of cutting and vibration process parameters(feed rate,rake angle,tangential amplitude,and frequency of vibration)on the variation of strain rates during machining of Inconel *** signal-to-noise analysis on an L18(2^1×3^3)orthogonal array was used to determine the optimum parametric combination for the maximum strain rate,and ANOVA was applied to evaluate the significance of control parameter factors on the strain *** results of the finite element analysis under different conditions illustrated that the feed rate and rake angle were negatively related to the strain rate,whereas the tangential amplitude and frequency had a positive ***,ANOVA results indicated that the effect of the feed rate,tool rake angle,vibration frequency,and tangential amplitude on the strain rate were all statistically significant,with a reliability level of 95%.Of these,the dominant parameter affecting the strain rate was the feed rate,with a percentage contribution of 40.36%.The estimation of the optimum strain rate and confirmation tests proved that the Taguchi method could successfully optimize the working conditions to obtain the desired maximum strain rate.

关键词： Elliptical vibration cutting Strain rate Finite element(FE) Taguchi method Analysis of variance(ANOVA)

冻融环境下玄武岩纤维增强泡沫混凝土的单轴压缩特性

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三峡大学学报（自然科学版） 2025年第1期47卷 1-8页

作者：吕国旭陈波周程涛詹明强河海大学水利水电学院南京210098 河海大学水灾害防御全国重点实验室南京210098 福建水口发电集团有限公司福州350001

为了研究密度、纤维掺量及冻融循环对玄武岩纤维增强泡沫混凝土单轴压缩特性的影响,借助X-CT技术以及Avizo软件对试件的孔隙构造进行了研究,对不同冻融环境下的多种密度等级(800和1000kg/m3)及纤维体积掺量(0%、0.15%、0.30%、0.45%)的... 详细信息

为了研究密度、纤维掺量及冻融循环对玄武岩纤维增强泡沫混凝土单轴压缩特性的影响,借助X-CT技术以及Avizo软件对试件的孔隙构造进行了研究,对不同冻融环境下的多种密度等级(800和1000kg/m3)及纤维体积掺量(0%、0.15%、0.30%、0.45%)的玄武岩纤维增强泡沫混凝土进行了单轴压缩试验,分析了不同影响因素下玄武岩纤维增强泡沫混凝土的单轴压缩特性,对各因素与抗压强度的关系进行了灰关联度分析,并使用机器学习算法模型对抗压强度进行预测.结果表明:掺入玄武岩纤维能有效提高泡沫混凝土抵抗冻融的能力,体积掺入0.15%、0.30%、0.45%的试件冻融80次后强度损失率分别为75.2%、46.2%、37.8%.密度等级与抗压强度关联度最大,灰关联度为0.799;其次是纤维掺量,关联系数为0.723;灰狼算法优化下的长短期记忆网络模型对玄武岩纤维增强泡沫混凝土抗压强度的预测性能良好.

关键词：玄武岩纤维增强泡沫混凝土单轴压缩冻融循环 X-CT 灰关联度长短期记忆网络灰狼优化算法