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Maser Emission of Relativistic Electrons Spiralling and Drifting in Curved Magnetic Fields

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Chinese Journal of Astronomy and Astrophysics 2007年第2期7卷 304-316页

作者： Jiong Liu Ye-fei Yuan Xiao-long Deng Center for Astrophysics University of Science and Technology of China Hefei 230026

Synchro-curvature radiation describes the emission from a relativistic charged particle which is moving and spiralling in a curved magnetic field. We investigate the maser emission for synchro-curvature radiation including drift of the guiding center of the radiating electron. It is shown that under some conditions the absorption coefficient can be negative, so maser can happen. These conditions are different from those needed for maser emission of curvature radiation including drift of the charged particles. We point out that our results, including the emissivity, can reduce to these of curvature radiation. Previously it was found that synchro-curvature radiation can not generate maser in vacuum, but we argue that synchrocurvature radiation including drift can generate maser even in vacuum. We discuss the possibilities of the potential applications of the synchro-curvature maser in modeling gamma ray bursts and pulsars.

关键词： masers - plasmas - radiation mechanisms non-thermal

Low-temperature superplasticity of cryorolled Ti-6Al-4V titanium alloy sheets

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Tungsten 2023年第4期5卷 522-530页

作者： fei-long Yu Charlie Kong Hai-Liang Yu State Key Laboratory of High Performance Complex Manufacturing Central South UniversityChangsha410083China College of Mechanical and Electrical Engineering Central South UniversityChangsha410083China Light Alloy Research Institute Central South UniversityChangsha410083China Mark Wainwright Analytical Centre University of New South WalesSydneyNSW2052Australia

To investigate the superplastic deformation behavior of cryorolled Ti-6Al-4V titanium alloy,tensile tests were carried out at760℃and 830℃with different strain *** evolution of grain and micro structure has been studied using transmission electron microscopy and electron backscatter *** the tensile temperature was 760℃(longation of the sample reached 385%,showing good low-temperature *** with the tensile temperature of 760℃,the fracture elongation of the s ample at 830℃was lower due to grain coarsening and *** strain rate sensitivity value m of all samples was larger than0.3,which confirmed that the cryorolled Ti-6A1-4V titanium alloy with a non-equiaxed grains structure can achieve high superplasticity at a temperature lower than 0.5T_(m),and indicated that the main deformation mechanisms in the tensile test at760-830℃were grain rotation and grain boundary *** the tensile test,the average grain size of all samples was less than 5μm,in which significant dynamic recrystallization and recovery occurred.

关键词： Ti-6Al-4V alloy Cryorolling Non-equiaxed grains structure Superplasticity

Simultaneous enhancement of mechanical properties and corrosion resistance of as-cast Mg-5Zn via microstructural modification by friction stir processing

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Journal of Magnesium and Alloys 2023年第6期11卷 1931-1943页

作者： fei long Gaoqiang Chen Mengran Zhou Qingyu Shi Qu Liu State Key Laboratory of Tribology Tsinghua UniversityBejjing 100084China Department of Mechanical Engineering Tsinghua UniversityBejjing 100084China

Magnesium alloys are ideal lightweight materials;however,their applications are extremely limited due to their low strength,poor ductility,and weak corrosion *** the present study,a friction stir processing(FSP)treatment was employed to optimize the mechanical properties and corrosion resistance of an as-cast Mg-5Zn *** average grain size of the Mg-5Zn alloy was refined from 133.8μm to1.3μm as a result of *** different directions,FSP exhibited the enhancement effects on different mechanical ***,according to the potentiodynamic polarization results,the corrosion current density at the free-corrosion potential of the FSPed sample,was 4.1×10^(-6)A/cm^(2)in 3.5 wt.%Na Cl aqueous solution,which was significantly lower than that of the as-cast *** impedance spectroscopy revealed that the polarization impedance,Rp,of the FSPed sample was 1534Ω/cm^(2)in 3.5 wt.%NaCl aqueous solution,which was 71.4%greater than that of the as-cast *** corrosion morphology of the FSPed sample in 3.5 wt.%NaCl aqueous solution exhibited largely uniform corrosion,rather than severe localized corrosion characteristics,which further reduced the corrosion depth on the basis of reducing the corrosion current *** results presented herein indicate that FSP is a viable technique for simultaneously improving the mechanical properties and corrosion resistance of the as-cast Mg-5Zn alloy.

关键词： Friction stir processing Magnesium alloy Corrosionmode Texture softening Anisotropy in mechanical properties

Biocompatibility of marine magnetotactic ovoid strain MO-1 for in vivo application

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Journal of Oceanology and Limnology 2021年第6期39卷 2107-2115页

作者： Changyou CHEN Pingping WANG long-fei WU Tao SONG Beijing Key Laboratory of Bioelectromagnetism Institute of Electrical EngineeringChinese Academy of SciencesBeijing 100190China France-China Joint Laboratory for Evolution and Development of Magnetotactic Multicellular Organisms Chinese Academy of SciencesBeijing 100029China Aix Marseille University CNRSLCBMarseille F-13402France University of the Chinese Academy of Sciences Beijing 100049China

Magnetotactic bacteria are capable of biosynthesizing magnetic nanoparticles,also called magnetosomes,and swimming along magnetic field *** abilities endow the whole cells of magnetotactic bacteria with such applications as targeted therapy and manipulation of *** have shown that the intact marine magnetotactic bacteria MO-1 kill efficiently antibiotic-resistant pathogen Staphylococcus aureus in vivo,but the biocompatibility of this marine bacterium is *** this study,the strain MO-1 was chosen to analyze its biocompatibility and potential for biomedicine *** showed that MO-1 cells could be guided at 37℃ under an external magnetic field and swim in the blood plasma and *** could keep active locomotivity within 40 min in the plasma and urine,although their velocity slowed *** incubated with human cells,magnetotactic bacteria MO-1 had no obvious effects on cellular viability at low dose,while the cell toxicity increased with the augmentation of the quantity of the MO-1 cells *** the in-vivo experiments,the median lethal dose of magnetotactic bacteria MO-1 in rats was determined to be 7.9×10^(10) bacteria/*** results provided the foundation for the biocompatibility and safety evaluations of magnetotactic bacteria MO-1 and suggested that they could be basically used in clinical targeted therapy.

关键词： magnetotactic bacteria motility cell interaction median lethal dose

Vertical dynamic response of the ballastless track on long-span plate-truss cable-stayed bridges

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Science China(Technological Sciences) 2015年第2期58卷 236-247页

作者： LI Yong Le SU Yang XIA fei long ZHANG Nan Department of Bridge Engineering Southwest Jiaotong University MOE Key Laboratory of High Speed Railway Engineering Southwest Jiaotong University Department of Bridge Engineering Northern Jiaotong University

An analytical model is presented to study vertical dynamic response of the ballastless track on long-span plate-truss cable-stayed bridges based on an explicit dynamic analysis *** the model,the train,ballastless track and bridge are treated as a coupled vibration system with *** simulating the dynamic process of the system,this paper discusses the distribution law of dynamic responses of the bridge deck and the bed *** shows the necessity of a base plate for the ballastless track on the long-span plate-truss cable-stayed *** of the influence of different train speeds and stiffness of the elastic vibration-damping pad on the dynamic responses of the bridge deck and the bed slab is also *** reasonable stiffness value of elastic vibration-damping pad is proposed.

关键词： long-span cable-stayed bridge plate-truss girder ballastless track train-induced vibration vehicle-bridge system

Classification and Comparison of Wave Impact Modes on Semi-Submersibles

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China Ocean Engineering 2021年第2期35卷 161-175页

作者： GUO Ying-hao XIAO long-fei WEI Han-di LI Xin LI Lei DENG Yan-fei State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China SJTU-Sanya Yazhou Bay Institute of Deepsea Technology Hainan 572024China CIMC Offshore Co.Ltd. Shenzhen 518000China

Semi-submersibles for offshore oil exploration and exploitation often suffer from severe wave impacts in extreme ocean *** to the complex wave interactions among structural components of semi-submersibles,in-depth analyses on the characteristics of wave impact events are of significance for both industry and *** experimental study was carried out to investigate the local wave impact loads on a semi-submersible,with focus on understanding the wave impacts by identifying typical impact *** criteria are proposed to classify major wave impacts on the semi-submersible into six modes and two *** results show that the classification is reasonable and provides valuable information for studying wave impacts on *** incident wave characteristics at the fore column of the semi-submersible have important influence on the wave impact *** fore-column dominating wave impacts exert the most intense loads on the fore column and feature well-developed breaking waves or slightly breaking waves at the fore ***,the aft-column dominating wave impacts exert the most intense loads on the aft column or the deck bottom and feature non-breaking waves at the fore *** loss during the fore-column impact weakens the impact severity on the aft column in the fore-column dominating wave *** shoaling effect of the submerged pontoon and different motion configurations of the platform result in higher occurrence rate of the aft-column dominating wave *** impact modes are also distinguished by different spatial distributions of wave impact loads.

关键词： wave impact load semi-submersible wave breaking energy loss shoaling effect

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立德树人视域下时代新人培育研究

湖北开放职业学院学报 2025年第3期38卷 146-147,153页

作者：宋昱璇龙飞宋岱岳沈阳工业大学辽宁沈阳110870

为社会主义伟大事业后继有人,按标准准确实现第二个百年奋斗目标,高等院校必须做奋进“领头羊”。培养一批又一批迎难而上、主动担当、适应党和国家的高层次人才。然而实现这一目标,我们必须紧紧围绕根本任务开展各项教育教学活动,将立... 详细信息

为社会主义伟大事业后继有人,按标准准确实现第二个百年奋斗目标,高等院校必须做奋进“领头羊”。培养一批又一批迎难而上、主动担当、适应党和国家的高层次人才。然而实现这一目标,我们必须紧紧围绕根本任务开展各项教育教学活动,将立德树人作为培养人才的“地基”。高校如何做才能达到立德树人这一期盼与要求便成为高校培养人才不可或缺的专题之一。

关键词：立德树人红色高校

铀对α-Al_(2)O_(3)中氢与本征点缺陷相互作用的影响

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原子与分子物理学报 2025年第5期42卷 123-129页

作者：杨飞龙向鑫胡立张桂凯陈长安中国工程物理研究院材料研究所江油621908

在长期高温服役过程中,铀床的氚渗透泄露问题是聚变堆涉氚系统中需要关注的焦点之一,而一种行之有效的解决思路是在内壁制备阻氚涂层.然而,服役过程中通过热扩散渗入涂层内部的铀可能在阻氚涂层氢行为中起作用,进而影响其服役可靠性.基... 详细信息

在长期高温服役过程中,铀床的氚渗透泄露问题是聚变堆涉氚系统中需要关注的焦点之一,而一种行之有效的解决思路是在内壁制备阻氚涂层.然而,服役过程中通过热扩散渗入涂层内部的铀可能在阻氚涂层氢行为中起作用,进而影响其服役可靠性.基于此,采用第一性原理计算方法,研究了铀对α-Al_(2)O_(3)中氢与本征点缺陷相互作用的影响.结果发现,铀对α-Al_(2)O_(3)中空位型本征点缺陷及氢相关缺陷的存在形式、电荷态及相对稳定性有重要影响.从形成能观点来看,铀对α-Al_(2)O_(3)中空位型本征点缺陷及氢相关缺陷的形成有利,且α-Al_(2)O_(3)中空位型点缺陷对氢的捕陷能力因铀的引入显著增加.研究结果对α-Al_(2)O_(3)基内壁阻氚涂层在氚工艺系统铀床中应用的可靠性评估具有重要的指导意义.

关键词：铀本征点缺陷氢相关缺陷相互作用 α-Al_(2)O_(3)

维普期刊数据库博看期刊

The Effect of Planting Oilseed Rape and Compost Application on Heavy Metal Forms in Soil and Cd and Pb Uptake in Rice

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Agricultural Sciences in China 2011年第2期10卷 267-274页

作者： WU fei-long LIN Dai-yan SU De-chun College of Resources and Environmental Sciences China Agricultural UniversityBeijing 100193P.R.China Institute of Agricultural Engineering Fujian Academy of Agricultural SciencesFuzhou 350013P.R.China

Pot experiments were conducted under greenhouse condition to investigate whether Cd and Pb uptake by rice could be reduced when it was rotated with oilseed rape and compost *** results showed that the rice grown after oilseed rape had significantly lower Cd and Pb concentrations in both straw and *** and Pb concentrations in the grains of the rice rotated with oilseed rape decreased by approximately 46-80% and 17-86%,respectively,although the Cd and Pb removal by oilseed rape ranged only from 2.39-3.67 and 0.032-0.13% of the total content in *** amendment also decreased the bioavailability of Cd and Pb in the soil and reduced Cd and Pb uptake by oilseed rapes and *** concentrations of Cd and Pb significantly decreased in the exchangeable and carbonate fractions and Pb concentration decreased in the organic matter and sulfide fractions in the contaminated soil after planting oilseed rapes.

关键词： heavy metal crop rotation compost oilseed rape rice