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Scissors vibration and its collective rotation in a microscopic investigation

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Chinese Physics C 2024年第12期48卷 118-128页

作者： fang-qi Chen School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China

The intrinsic vibrational motion and the rotational behavior of the scissors mode in well deformed nuclei are investigated with an angular-momentum-projected approach,which is interpreted as a generator-coordinatemethod with the generator coordinates corresponding to the degrees of freedom of *** picture of the intrinsic and rotational motion of the scissors mode is illustrated from the collective wave function within the framework of the *** harmonicity of the scissors vibration is found to arise naturally from the present model but can be disturbed by the Coriolis effect as spin *** odd and even spin members of the rotational band based on the scissors mode rotate about different axes perpendicular to each other,leading to the flipping moment of inertia and the consequent splitting behavior that has been suggested previously.

关键词： scissors mode collective rotation odd-even staggering angular momentum projection generator coordinate method

一元溶剂体系TKX-50结晶形貌的分子动力学模拟

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原子与分子物理学报 2025年第4期42卷 163-167页

作者：董羚陈芳李天浩郭国琦贾翔宇米方琦宁瑞星中北大学化学与化工学院太原030051

本文应用分子动力学方法(MD)和修正的Dreiding-TKX-50力场计算了三种单溶剂作用下TKX-50重要晶面层与溶剂层的相互作用能,采用修正的附着能模型预测了TKX-50在不同溶剂中的结晶形貌并与实验结果进行了对比.计算结果表明,TKX-50晶体真空... 详细信息

本文应用分子动力学方法(MD)和修正的Dreiding-TKX-50力场计算了三种单溶剂作用下TKX-50重要晶面层与溶剂层的相互作用能,采用修正的附着能模型预测了TKX-50在不同溶剂中的结晶形貌并与实验结果进行了对比.计算结果表明,TKX-50晶体真空形貌中的重要晶面为(020)、(011)、(11-1)和(100).水(H_(2)O)溶剂和N,N-二甲基甲酰胺(DMF)溶剂作用后所预测的TKX-50晶体形貌近似梭形,纵横比为1.857和2.073.乙二醇(EG)溶剂作用后所预测的TKX-50晶体形貌为块体,纵横比为2.320.

关键词：附着能结晶形貌分子动力学 TKX-50 溶剂

Single-pulse chaotic dynamics of functionally graded materials plate

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Acta Mechanica Sinica 2013年第4期29卷 593-601页

作者： Yu-Gao Huangfu fang-qi Chen College of Mathematics and Information Science Henan Polytechnic University Department of Mathematics Nanjing University of Aeronautics and Astronautics

Single-pulse chaos are studied for a functionally graded materials rectangular plate. By means of the global perturbation method, explicit conditions for the existence of a SiZnikov-type homoclinic orbit are obtained for this sys- tem, which suggests that chaos are likely to take place. Then, numerical simulations are given to test the analytical predic- tions. And from our analysis, when the chaotic motion oc- curs, there are a quasi-period motion in a two-dimensional subspace and chaos in another two-dimensional supplemen- tary subspace.

关键词： Functionally graded materials ~ Single-pulse ~Melnikov's method ~ Homoclinic orbit ~ Numerical simula-tion

Chaotic Motions of the van der Pol-Duffing Oscillator Subjected to Periodic External and Parametric Excitations with Delayed Feedbacks

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Acta Mathematicae Applicatae Sinica 2024年第4期40卷 1111-1126页

作者： Liang-qiang ZHOU fang-qi CHEN School of Mathematics Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Chaotic dynamics of the van der Pol-Duffing oscillator subjected to periodic external and parametric excitations with delayed feedbacks are investigated both analytically and numerically in this *** the Melnikov method,the critical value of chaos arising from homoclinic or heteroclinic intersections is derived *** feature of the critical curves separating chaotic and non-chaotic regions on the excitation frequency and the time delay is investigated analytically in *** monotonicity of the critical value to the excitation frequency and time delay is obtained *** is presented that there may exist a special frequency for this *** this frequency,chaos in the sense of Melnikov may not occur for any excitation *** also exists a uncontrollable time delay with which chaos always occurs for this *** simulations are carried out to verify the chaos threshold obtained by the analytical method.

关键词： Van der Pol-Duffing oscillator time delay chaos parametric excitation Melnikov method

Estimates for parametric Marcinkiewicz integrals in BMOand Campanato spaces

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Applied Mathematics(A Journal of Chinese Universities) 2011年第2期26卷 230-252页

作者： fang qi-quan SHI Xian-liang College of Mathematics and Computer Science Hunan Normal University Changsha Hunan 410081China

In this paper, the authors consider the behaviors of a class of parametricMarcinkiewicz integrals μ_Ω~ρ, μ_（Ω,）^（＊,）~ρ_λ and μ_Ω~ρ,S on BMO（Rn） and Campanato spaces with com-plex parameter ρ and the kernel Ω in Llog~＋ L（S^（n-1））. Here μ_（Ω,）^（＊,）~ρ_λand μ_Ω~ρ,S are parametricMarcinkiewicz functions corresponding to the Littlewood-Paley g_λ~＊-function and the Lusin areafunction S, respectively. Under certain weak regularity condition on Ω, the authors prove thatif f belongs to BMO（Rn） or to a certain Campanato space, then [μ_（Ω,）^（＊,）~ρ_λ（f）]~2, [μ_Ω~ρ,_S（f）]~2 and[μ_Ω~ρ（f）]~2 are either infinite everywhere or finite almost everywhere, and in the latter case, somekind of boundedness are also established.

关键词： parametric Marcinkiewicz integrals Campanato space weak Dini-type regularity condition.

A Model for Precipitation Kinetics in Vanadium Microalloyed Steel

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Journal of Iron and Steel Research International 2010年第2期17卷 36-42页

作者： fang fang YONG qi-long YANG Cai-fu SU Hang Structure Material Institute Central Iron and Steel Research Institute Beijing 100081 China

Small dispersoid particles inhibit recrystallization which is critical in controlling the grain structure of many high strength low alloy steels. A general kinetic model has been developed to predict precipitation of V（C, N） in vanadium microalloyed steels with a series of carbon and nitrogen contents. The solubility product and driving force of carbonitrides precipitated in austenite as well as the interracial energy and other parameters can be evaluated to predict Nucleation rates-Temperature （NrT） and Precipitation-Time-Temperature （PTT） diagram. By using stress relaxation tests and fitting with Avrami equation, it is possible to draw PTT diagrams. The predictions of the model coincide with results of experimental investigation on V（C, N） precipitation in austenite. The nose temperature is around 850 ℃ obtained by experiment which is different from the prediction of the model and the difference is 30 ℃, and nitrogen has more effect on the shape of ＂C＂ curve of PTT diagram than carbon that makes ＂C＂ curve move leftward significantly.

关键词： kinetic calculation model PTT curve stress relaxation nitrogen

Paleoenvironmental Evolution of the Beilun River Estuary,Northwest South China Sea,During the Past 20,000 Years Based on Diatoms

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Acta Geologica Sinica(English Edition) 2016年第6期90卷 2244-2257页

作者： CHEN Min qi Hongshuai LAN Dongzhao LAN Binbin fang qi Third Institute of Oceanography State Oceanic Administration

The paleoenvironmental history of the Beilun River estuary on the coast of Beibu Gulf in the northwest South China Sea is reconstructed based on fossil diatoms, isotopic dating, sedimentary grain size data, mineralogy and geochemistry in three sediment core samples. Results show that the estuary has experienced significant environmental changes since deposition began about 20,000 yr ago. Freshwater runoff of the Beilun River initially was strong. However, the freshwater runoff reduced significantly after a transgressive event. Subsequently the estuary’s position began to migrate to the northeast. At the end of the Late Pleistocene the estuary shifted gradually towards the southwest. In the Early-Mid Holocene, the estuary’s geomorphology was shaped by seawater transgressing into the ancient river channel. The basin was filled continuously but slowly to form the present Beilun River estuary. Holocene transgression in this area could be divided roughly into three stages, including oscillation period 1, the maximum transgression period, and oscillation period 2.

关键词： diatoms Beilun River estuary paleoenvironment Quaternary

Flux-pinning-induced stress behaviors in a long superconducting slab with central cuboid hole

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Acta Mechanica Sinica 2021年第8期37卷 1255-1263,I0001页

作者： qi-fang Liu Wen-Jie Feng Jia-Yu Liu School of Civil Engineering Shandong UniversityJinan 250061China State Key Lab Mech Behav&Syst Safety Traff Engn Shijiazhuang Tiedao UniversityShijiazhuang 050043China Hebei Key Lab Smart Mat&Struct Mech Shijiazhuang Tiedao UniversityShijiazhuang 050043China

This paper investigates the flux-pinning-induced stress behaviors in a long superconducting slab with a central cuboid *** distribution of flux density is analytically derived for the critical current density of Kim model by considering the effects of the *** concentration of stress for both of the zero-field cooling(ZFC)and the field cooling(FC)magnetization processes are investigated through numerical simulation by using finite element *** results indicate the potential failure mode varies with the height-width ratio and the dimensions of the *** to the case of infinite hole height,the stress concentration behavior for the FC process is more critical when the dimensions of the hole are *** findings in this paper are useful for understanding of the degrade mechanism of superconductor in service and the design of new system.

关键词： Electromagnetic force Cuboid hole Stress concentration factor Superconducting slab

Microstructure and Precipitation Behavior in HAZ of V and Ti Microalloyed Steel

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Journal of Iron and Steel Research International 2009年第3期16卷 68-72,77页

作者： fang fang YONG qi-long YANG Cai-fu SU Hang China Iron and Steel Research Institute Group Beijing 100081 China

Three steels containing 0.05%C-0.1%V-0.01%N （steel V-LN）,0.05%C-0.1%V-0.02%N （steel V-HN）,and 0.05%C-0.1%V-0.02%N-0.01%Ti （steel V-HN-Ti）,which were all essentially vanadium microalloyed steels,were subjected to simulating the microstructure of a coarse grained heat affected zone （CGHAZ）. The process involved reheating to 1 350 ℃,rapid cooling to room temperature,and varying the welding heat input from 15 kJ/cm to 54 kJ/cm,including four cooling rates of t8/5 equal to 7.5 s,20 s,40 s,100 s,and the relationship of heat input to t8/5 was calculated by Quiksim software. The microstructure and precipitation of vanadium and titanium carbon nitrides are studied. The results indicate that the microstructure consists of granular bainite and some side plate ferrite in the grain boundary when the steels are produced with the highest heat input. As the heat input decreased,numerous polygonal ferrites and grain boundary ferrites appeared,and the size apparently increased. When the steel contained high nitrogen,it was considerably easier to form martensite-austenite island,which was even worse for the toughness and other properties of the steel. For the limitation of cooling time,vanadium carbon nitrides could not precipitate sufficiently,but as titanium was added,the unmelted or precipitated TiN on cooling absorbed some fraction of nitrogen in the matrix and made more precipitate positions for the round V（C,N）,and thus several useful round particles could be seen in titanium-contained steel,and most of them were around TiN. By this experiment,we can conclude that with the help of titanium,nitrogen-enhanced steel had a better prior austenite grain size,was considerably easier to precipitate,reduced free nitrogen in the matrix effectively,and provided a very effective mechanism for restriction grain growth in the HAZ.

关键词： precipitate weld input toughness nitrogen