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Repelling effects of Mg on diffusion of He atoms towards surface in SiC: Irradiation and annealing experiments combined with first-principles calculations

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Journal of Advanced Ceramics 2023年第12期12卷 2284-2299页

作者： Min Liu Qiqi Li jun hui Yongfeng Yan Renduo Liu Biao Wang Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China School of Materials Science and Engineering Dongguan University of TechnologyDongguan 523000China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China

In this study,the effects of Mg on the formation of He bubbles and diffusion behavior of He atoms in cubic silicon carbide(3C–SiC)were investigated by irradiation and annealing experiments as well as first-principles calculations.TEM results indicated that two damage bands were formed in He&Mg irradiated SiC.During annealing,Mg could prevent He atoms from diffusing to the surface,resulting in the formation of the He bubbles in the deeper areas far from Mg-implanted regions,which is helpful in avoiding surface blisters.First-principles calculations were then performed to explore the effects of Mg on the He behavior in SiC.The solution energy,binding energy charge density,bond length,and crystal orbital Hamiltonian population of these elements were calculated to identify their states.The results suggested that the binding capacity between He and Mg was weak,and Mg could increase the diffusion energy barrier of He.Ab initio molecular dynamics(AIMD)simulation showed that Mg could make He in a high-energy unstable state,and force He atom to move toward the vacancy away from Mg,which explains the experimental results.

关键词： SiC irradiation He bubbles Mg ab initio molecular dynamics(AIMD)

Probing the Gamma-Ray Emission Region of Five TeV Flat Spectrum Radio Quasars

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Research in Astronomy and Astrophysics 2024年第6期24卷 158-171页

作者： Hu-Bing Xiao Hai-Tao Cao Rui Xue Jin-Ting Cai Ge-Ge Wang Marina Manganaro Shao-Hua Zhang Zhi-Hao Ouyang Li-Ping Fu jun-hui Fan Shanghai Key Lab for Astrophysics Shanghai Normal University School of Information Engineering Department of Physics Zhejiang Normal University College of Mathematics and Physics Guangxi Minzu University Key Laboratory of Cosmology and Astrophysics (Liaoning) College of Sciences Northeastern University Department of Physics University of Rijeka Center for Astrophysics Guangzhou University Key Laboratory for Astronomical Observation and Technology of Guangzhou Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province

The location of γ-ray emission of blazars remains a contested topic, inspiring the development of numerous investigative techniques to address this issue. In this work, we analyzed Fermi γ-ray light curves in the GeV and MeV bands, employing the discrete cross-correlation function method to discern time lags between the two bands.For 4C +21.35, Ton 599, B2 1420+32, and PKS 1510-089, we identified a time lag spanning several days, while for PKS 1441+25, the time lag was not statistically found. The results imply that the soft photons necessary for inverse Compton scattering predominantly originate from the dusty torus in the first four sources, whereas for PKS1441+25, they seem to be sourced mainly from the broad-line region. Further analysis of the opacity(τγγ) and the GeV spectra study supports the conclusion that the location of the dissipation region must be beyond the BLR to avoid significant absorption. Notably, for PKS 1441+25, the emission region is also posited to lie outside yet proximate to the BLR. The parameters of describing the emission region were obtained by fitting broadband spectral energy distribution with contemporaneous observation data. Our findings suggest that for the five TeV FSRQs, during Te V flaring events, the jet appears to maintain an equilibrium between the energy density of the magnetic field and that of the particles for all investigated sources, with the exceptions of 4C +21.35 and PKS1441+25. In terms of the overall jet power, particle energy is the dominant contributor, and the observed blazar radiation cannot be solely attributed to the magnetic field, except in the case of 4C +21.35. Consequently,magnetic reconnection is unlikely to be the primary mechanism behind particle acceleration in these systems.

关键词： galaxies: active galaxies: jets gamma-rays: galaxies

Elucidating ligand effects in rhodium(Ⅲ)-catalyzed arene-alkene coupling reactions

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Chinese Chemical Letters 2024年第5期35卷 130-134页

作者： Kongchuan Wu Dandan Lu Jianbin Lin Ting-Bin Wen Wei Hao Kai Tan hui-jun Zhang Department of Chemistry College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of Sciences(CAS)Beijing 100190China

Rhodium(Ⅲ)-catalyzed C-H couplings of arenes with alkenes are among the most powerful methods for C-C bond formation.For these transformations,subtle manipulation of ancillary ligands can lead to dramatic changes in reactivity and selectivity.However,detailed mechanistic studies concerning the ligand effects are rare.In this study,we investigated the origin of ligand-controlled product-selectivity in rhodium(Ⅲ)-catalyzed C-H couplings of arenes with alkenes,using a series of well-defined[CpXRhⅢ]complexes that feature electronically or sterically distinct Cp^(X)(Cp(η^(5)-C_(5)H_(5)),Cp^(CF3)(η^(5)-C_(5)Me_(4)CF_(3))and Cp^(∗)(η^(5)-C_(5)Me_(5)))ligands.A combination of experimental and theoretical investigations showed that(i)rhodium hydride species containing the electron rich Cp^(∗)ligand can undergo reinsertion of the alkene,thereby allowing rhodium-walking,(ii)rhodium hydride species involving the electron-deficient Cp or Cp^(CF3) ligands prefer reductive elimination rather than alkene insertion.These findings offer valuable insights on future rational catalyst design for selective arene-alkene cross coupling reactions.

关键词： Organometallics Transition metal catalysis Arene-alkene coupling β-H elimination Rhodium hydride

Design and prototyping of the readout electronics for the transition radiation detector in the high energy cosmic radiation detection facility

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Nuclear Science and Techniques 2024年第4期35卷 189-199页

作者： Jie-Yu Zhu Yang-Zhou Su Hai-Bo Yang Fen-Hua Lu Yan Yang Xi-Wen Liu Ping Wei Shu-Cai Wan Hao-Qing Xie Xian-Qin Li Cong Dai hui-jun Hu Hong-Bang Liu Shu-Wen Tang Cheng-Xin Zhao Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Guangxi Key Laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China

The high energy cosmic-radiation detection(HERD)facility is planned to launch in 2027 and scheduled to be installed on the China Space Station.It serves as a dark matter particle detector,a cosmic ray instrument,and an observatory for high-energy gamma rays.A transition radiation detector placed on one of its lateral sides serves dual purpose,(ⅰ)calibrating HERD's electromagnetic calorimeter in the TeV energy range,and(ⅱ)serving as an independent detector for high-energy gamma rays.In this paper,the prototype readout electronics design of the transition radiation detector is demonstrated,which aims to accurately measure the charge of the anodes using the SAMPA application specific integrated circuit chip.The electronic performance of the prototype system is evaluated in terms of noise,linearity,and resolution.Through the presented design,each electronic channel can achieve a dynamic range of 0–100 fC,the RMS noise level not exceeding 0.15 fC,and the integral nonlinearity was<0.2%.To further verify the readout electronic performance,a joint test with the detector was carried out,and the results show that the prototype system can satisfy the requirements of the detector's scientific goals.

关键词： HERD Dark matter particle detection TRD Readout electronics SAMPA Data acquisition Performance test

Theoretical study of the effects of alloying elements on Cu nanotwins

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Science China(Physics,Mechanics & Astronomy) 2020年第10期63卷 81-90页

作者： jun hui Wenguan Liu Biao Wang Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China

Nanotwins form in many metallic materials to improve their strength and toughness.In this study,we thoroughly studied the alloying effects of 10 common metal and nonmetal elements on Cu nanotwins by density functional theory(DFT).We calculated the segregation energies to determine if Cu nanotwins attract both the metal and nonmetal alloying elements;these segregation energies were then decomposed to mechanical and chemical components.The Cu-Sn bonds are different from other metal alloying elements,and the strong bond between Cu and the nonmetal element results in the negative values of the chemical contribution.Furthermore,the temperature and concentration have different effects on the nanotwin formation energy of the metal and nonmetal alloying elements.As determined by the Generalized Stacking Fault Energy,Al and nonmetals can inhibit the migration of Cu nanotwin boundary,and the effects of Li,Mg,and Sn are opposite.Our theoretical study serves as the foundation for the engineering nanotwin structures through alloying elements,the elements that may lead to new alloy compositions and thermomechanical processes,and are important complements to the experimental research.

关键词： nanotwin alloying element density functional theory segregation energy nanotwin formation energy generalized stacking fault energy

二维激子-极化子凝聚体中冲击波的产生与调控

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物理学报 2024年第11期73卷 385-393页

作者：王金玲张昆林机李慧军浙江师范大学非线性物理研究所金华321004 浙江师范大学浙江光电子研究院与浙江先进光源研究院金华321004

由于半导体微腔中形成的激子-极化子凝聚体能在室温实现,且具有非平衡、强相互作用等特性,其成为研究非平衡量子系统非线性特性的一个理想平台.本文采用谱方法与四阶龙格库塔法,探究二维极化子凝聚体中产生和调控冲击波的方案.发现,若... 详细信息

由于半导体微腔中形成的激子-极化子凝聚体能在室温实现,且具有非平衡、强相互作用等特性,其成为研究非平衡量子系统非线性特性的一个理想平台.本文采用谱方法与四阶龙格库塔法,探究二维极化子凝聚体中产生和调控冲击波的方案.发现,若在高凝聚率时淬火凝聚体与热库之间的交叉相互作用,可将初始制备的亮孤子调制成两种波速不同的旋转对称型冲击波,而初始的类暗孤子只能转变成单一波速的旋转对称型冲击波;若淬火外势,则可将类暗孤子转化成各向异性的超声速冲击波,并给出冲击波对外势宽度的依赖关系.若在低凝聚率时调控外势和非相干泵浦,可在均匀凝聚体中激发出多种各向异性冲击波,还可通过它们的振幅调控冲击波的波数和振幅,并展示了激发冲击波所需外势或非相干泵浦的宽度范围.文中方案不仅为激子-极化子凝聚体中产生和调控冲击波提供理论指导,找到了与实验相似的对称型冲击波,而且为非平衡或不可积系统中激发冲击波开辟了一条普适捷径,可能成为调控孤子向冲击波转变的一种范式.

关键词：冲击波孤子激子-极化子凝聚体非相干泵浦

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子宫颈癌的免疫治疗

中国实用妇科与产科杂志 2024年第1期40卷 41-44页

作者：刘萍白惠君南方医科大学南方医院妇产科广东广州510515

近几年有研究以免疫治疗运用于子宫颈恶性肿瘤并取得一定的成效,其中包括检查点抑制剂(immune checkpoint inhibitors)、基于树突状细胞的治疗(dendritic cell-based therapy)、免疫T细胞移植(adoptive T-cell transfer)、肿瘤浸润淋巴... 详细信息

近几年有研究以免疫治疗运用于子宫颈恶性肿瘤并取得一定的成效,其中包括检查点抑制剂(immune checkpoint inhibitors)、基于树突状细胞的治疗(dendritic cell-based therapy)、免疫T细胞移植(adoptive T-cell transfer)、肿瘤浸润淋巴细胞免疫细胞移植(tumor infiltrating lymphocytesadoptive cell transfer)、基于细胞毒性T淋巴细胞的免疫疗法(cytotoxic T lymphocytes-based immunotherapy)、使用DC-CIK治疗因子诱导的杀伤细胞的免疫疗法(cytokine-induced killer cell-based immunotherapy)、基于DNA的免疫疗法(DNAbased immunotherapy)。免疫治疗的方法包括结合不同免疫治疗方法,或与放化疗结合使用。这些方法为子宫颈癌的治疗提供了新的希望。然而,免疫治疗的机制和制备过程复杂,且个体化治疗要求高,制备效率低、价格昂贵、周期长等问题亟待解决,需要进一步研究和临床共同努力。

关键词：子宫颈癌免疫治疗树突细胞免疫T细胞移植肿瘤浸润淋巴细胞细胞毒性T淋巴细胞

Effects of impurity elements on SiC grain boundary stability and corrosion

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Nuclear Science and Techniques 2021年第11期32卷 77-95页

作者： jun hui Bao-Liang Zhang Tao Liu Min Liu Wen-Guan Liu Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China China Institute of Atomic Energy Beijing 102413China

Grain boundaries(GBs)have critical influences on the stability and properties of various materials.In this study,first-principles calculations were performed to determine the effects of four metallic impurities(Ni,Al,Bi,and Pb)and three nonmetallic impurities(H,O,and N)on the GBs of silicon carbide(SiC),using the ∑5(210)GBs as models.The GB energy and segregation energy(SE)were calculated to identify the effects of impurities on the GB stability.Electronic interactions considerably influenced the bonding effects of SiC.The formation of weak bonds resulted in the corrosion and embrittlement of GBs.The co-segregation of Bi,Pb,and O was also investigated in detail.

关键词： SiC First-principles calculation Grain boundary Impurity atom Co-segregation

个人信息保护影响评估制度的优化路径--基于元治理理论视阈

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中南民族大学学报（人文社会科学版） 2024年第5期44卷 147-155,222页

作者：张德淼李慧君中南财经政法大学法学院湖北武汉430073

个人信息保护影响评估制度的革新意义,在于“对传统风险评估制度的矫正纠偏”和“对个人信息保护方式的弥补与强化”,该制度在提高个人信息处理透明度、改善信息主体弱势地位、协调公私利益等方面发挥着积极作用。现有个人信息保护影响... 详细信息

个人信息保护影响评估制度的革新意义,在于“对传统风险评估制度的矫正纠偏”和“对个人信息保护方式的弥补与强化”,该制度在提高个人信息处理透明度、改善信息主体弱势地位、协调公私利益等方面发挥着积极作用。现有个人信息保护影响评估制度存在评估范围不详备、评估制度落实不严格、程序性设置不合理等弊端。元治理理论以自我规制为主,以有限政府规制为辅,与个人信息保护影响评估所追求的“全面性、动态性”的目标框架相契合,为优化个人信息保护影响评估制度提供了理念指引。应着力于完善个人信息保护影响评估制度的程序性规定,使评估适用范围向精细化和场景化转型,构建个人信息保护影响评估指标体系。

关键词：个人信息保护影响评估元治理风险评估个人信息保护法