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β-Ga_(2)O_(3)热电性能的第一性原理计算

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原子与分子物理学报 2025年第1期42卷 180-188页

作者：邓南发周贤中广东工业大学集成电路学院广州510006

通过使用第一性原理计算方法和玻尔兹曼输运理论,计算了β-Ga_(2)O_(3)的电学、热学和热电性质,并得出了热电性能因子随载流子浓度和温度的变化规律.此外,还考虑了声子散射和极性光学声子散射对平均电子弛豫时间的影响,并详细描述了不... 详细信息

通过使用第一性原理计算方法和玻尔兹曼输运理论,计算了β-Ga_(2)O_(3)的电学、热学和热电性质,并得出了热电性能因子随载流子浓度和温度的变化规律.此外,还考虑了声子散射和极性光学声子散射对平均电子弛豫时间的影响,并详细描述了不同载流子浓度和温度下β-Ga_(2)O_(3)的Seebeck系数、电导率、电热导率和功率因数的计算结果.最后,给出了β-Ga_(2)O_(3)的热电性能因子随载流子浓度和温度的变化趋势.结果表明,在高载流子浓度和高温下,β-Ga_(2)O_(3)具有较高的热电性能因子.

关键词： Ga_(2)O_(3) 第一性原理计算波尔兹曼输运理论热电性质

有机金属卤化物钙钛矿CH_(3)NH_(3)PbBr_(3)的各向异性Rashba效应

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原子与分子物理学报 2025年第6期42卷 153-158页

作者：蔡锦鸿余达明周贤中广东工业大学集成电路学院广州510006

本研究通过密度泛函理论结合全相对论赝势对钙钛矿CH_(3)NH_(3)PbBr_(3)中的各向异性Rashba效应进行了深入研究.发现,Pb-Br八面体的畸变引起了导带最小间隙的三重态在自旋轨道耦合(SOC)效应和晶格形变下的分裂,导致在不同方向上呈现出... 详细信息

本研究通过密度泛函理论结合全相对论赝势对钙钛矿CH_(3)NH_(3)PbBr_(3)中的各向异性Rashba效应进行了深入研究.发现,Pb-Br八面体的畸变引起了导带最小间隙的三重态在自旋轨道耦合(SOC)效应和晶格形变下的分裂,导致在不同方向上呈现出强烈的各向异性.Rashba带分裂的最大系数可达2.0 eV?,并通过分析能级和电荷密度分布解释了Rashba效应的形成机制.这些研究结果有助于深化对CH_(3)NH_(3)PbBr_(3)性质的理解,同时为其在自旋电子学领域的潜在应用提供了理论基础.

关键词：钙钛矿 CH_3NH_3PbBr_3 密度泛函理论自旋轨道耦合

Stabilization/solidification mechanisms of tin tailings and fuming slag-based geopolymers for different heavy metals

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Frontiers of Environmental Science & Engineering 2024年第5期18卷 43-55页

作者： xian zhou Zhengfu Zhang Hui Yang School of Materials Science and Engineering Kunming University of Science and TechnologyKunming650093China Kunming Metallurgical Research Institute Co. Ltd.Kunming650031China

Tin mine tailings(TMT)and fuming slag(FS)contain many heavy metals(As,Cr,Cu,Zn and Mn)that cause severe pollution to the ***,geopolymers were prepared using TMT,FS and flue gas desulfurization gypsum(FGDG)to immobilize heavy metals,and their compressive strength and heavy metal leaching toxicity were *** was first determined that T4F5(TMT:FS=4:5)sample exhibited the highest compressive strength(7.83 MPa).T4F5 achieved 95%immobilization efficiency for As and Cr,and nearly 100%for Cu,Zn and Mn,showing good immobilization performance.A series of characterization analyses showed that heavy metal cations can balance the charge in the geopolymer and replace Al in the geopolymer structure to form covalent *** addition,about 2%–20%of heavy metal Fe was immobilized in hydration products,heavy metal hydroxides and non-bridging Si–O and Al–O coordination with silica-aluminate ***_(3)^(3−) was oxidized into AsO_(4)^(3−),which may form Ca–As or Fe–As ***_(2)O_(7)^(2−)was converted to CrO_(4)^(2−)under alkaline environment and then combined with OH−to form Cr(OH)3 ***^(2+)may react directly with dissolved silicate to form Mn_(2)SiO_(4) and also form Mn(OH)_(2) *** unstable Mn(OH)_(2) can be further oxidized to MnO_(2).The heavy metal cations were immobilized in the silicoaluminate lattice,while the anions tended to form insoluble *** results may benefit the industry and government for better handling of TMT,FS and solid wastes containing the abovementioned five heavy metals.

关键词： Heavy metals Cementitious materials Tin tailings Stabilization/solidification Redox

Efficient Estimation and Variable Selection in Dynamic Panel Data Partially Linear Varying Coefficient Models with Incidental Parameter

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Acta Mathematicae Applicatae Sinica 2015年第3期31卷 643-664页

作者： Rui LI xian zhou School of Statistics and Management Shanghai University of Finance and Economics Department of Applied Finance and Actuarial Studies Macquarie University

This paper is concerned with the statistical inference of partially linear varying coefficient dynamic panel data model with incidental parameter, including efficient estimation of the parametric and nonparametric components and consistent determination of the lagged order. For the parametric component, we propose an efficient semiparametric generalized method-of-moments（GMM） estimator and establish its asymptotic normality. For the nonparametric component, B-spline series approximation is employed to estimate the unknown coefficient functions, which are shown to achieve the optimal nonparametric convergence rate. A consistent estimator of the variance of error component is also constructed. In addition, by using the smooth-threshold GMM estimating equations, we propose a variable selection method to identify the significant order of lagged terms automatically and remove the irrelevant regressors by setting their coefficient to zeros. As a result, it can consistently determine the true lagged order and specify the significant exogenous variables. Further studies show that the resulting estimator has the same asymptotic properties as if the true lagged order and significant regressors were known prior, i.e., achieving the oracle property. Numerical experiments are conducted to evaluate the finite sample performance of our procedures. An example of application is also illustrated.

关键词： dynamic semiparametric model fixed effect B-spline GMM estimator oracle property

Research on the influence of quadrupole deformation and continuum effects on the exotic properties of 15,17,19B with the complex momentum representation method

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Nuclear Science and Techniques 2023年第2期34卷 98-108页

作者： Xue‑Neng Cao xian‑xian zhou Ming Fu Xin‑Xing Shi School of Management Science and Engineering Anhui University of Finance and EconomicsBengbu 233030China School of Mechanics and Optoelectronic Physics Anhui University of Science and TechnologyHuainan 232001China

The properties of exotic nuclei are the focus of the present ***-neutron halo structures of neutron-rich17,19B were experimentally *** studied the formation mechanism of halo phenomena in17,19B using the complex momentum representation method applied to deformation and continuum *** examining the evolution of the weakly bound and resonant levels near the Fermi surface,s–d orbital reversals and certain prolate deformations were *** addition,by analyzing the evolution of the occupation probabilities and density distributions occupied by valence neutrons,we found that the ground state of15B did not exhibit a halo and the ground states of17B and19B exhibited halos at 0.6≤β2≤0.7 and0.3≤β2≤0.7,*** low-l components in the valence levels that are weakly bound or embedded in the continuous spectrum lead to halo formation.

关键词： Quadrupole deformation Resonant states Complex momentum representation Halo

More about the Kernel Convergence and the Ideal Convergence

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Acta Mathematica Sinica,English Series 2013年第12期29卷 2367-2372页

作者： xian Geng zhou Min ZHANG Department of Mathematics Ningde Normal University

Let I 2N be an ideal and let XI = span{χI ： I ∈ I}, and let pI be the quotient norm of l∞/XI. In this paper, we show first that for each proper ideal I 2N, the ideal convergence deduced by I is equivalent to pI-kernel convergence. In addition, let K = {x＊oχ（·）： x＊∈ p（e）}, where p（x） = lim supn→∞1/n（∑k=1n｜x（k）｜, and let Iμ = {A N ： μ（A） = 0} for all μ = x＊oχ（·） ∈ K. Then Iμ is a proper ideal. We also show that the ideal convergence deduced by the proper ideal Iμ, the p-kernel convergence and the statistical convergence are also equivalent.

关键词： Kernel convergence ideal convergence statistical convergence seminorm Banach space

Measurement Error in Proportional Hazards Models for Survival Data with Long-term Survivors

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Acta Mathematicae Applicatae Sinica 2012年第2期28卷 275-288页

作者： Xiao-bing ZHAO xian zhou School of Mathematics and Statistics Zhejiang University of Finance and Economics Hangzhou 310018 China Department of Applied Finance and Actuarial Studies Macquarie University North Ryde Sydney NSW 2109Australia

This work studies a proportional hazards model for survival data with ＂long-term survivors＂, in which covariates are subject to linear measurement error. It is well known that the naive estimators from both partial and full likelihood methods are inconsistent under this measurement error model. For measurement error models, methods of unbiased estimating function and corrected likelihood have been proposed in the literature. In this paper, we apply the corrected partial and full likelihood approaches to estimate the model and obtain statistical inference from survival data with long-term survivors. The asymptotic properties of the estimators are established. Simulation results illustrate that the proposed approaches provide useful tools for the models considered.

关键词： proportional hazards counting process long-term survivor measurement error corrected scorefunction

Impurity effects of theΛhyperon in the hypernuclear systems^(25)ΛMg and(29)ΛSi

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Communications in Theoretical Physics 2021年第11期73卷 116-121页

作者： Ji-Wei Cui xian-Rong zhou School of Physics and Optoelectronic Engineering Xidian UniversityXi'an 710071China Department of Physics East China Normal UniversityShanghai 200241China

Based on the beyond-mean-field Skyrme-Hartree-Fock model,impurity effects of theΛhyperon in the hypernuclear systems^(25)ΛMg and^(29)ΛSi are investigated,*** cases,in which theΛhyperon occupies the single-particle orbitals L[000]1+/2,L[110]1-/2,L[101]3-/2 and L[101]1-/2,are *** each case,the potential energy surface and the energy curves projected on certain angular momenta are employed to show the influence of theΛhyperon on the nuclear *** the shrinkage effect that is induced by theΛhyperon occupying the sΛorbital,it is found that theΛhyperon on the pΛorbital,L[110]1-/2,drives the nuclear core toward a prolate shape,while the ones on the other two pΛorbitals,L[101]3-/2 and L[101]1-/2,drive the nuclear core toward an oblate *** energy spectra and the corresponding intra-band E2 transition rates for the rotational bands are given as a prediction for future experiments.

关键词： Λhypernuclei Skyrme-Hartree-Fock model angular momentum projection generator coordinate method

Effects of fulvic acid and humic acid from different sources on Hg methylation in soil and accumulation in rice

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Journal of Environmental Sciences 2022年第9期34卷 93-105页

作者： Shu Ran Tianrong He xian zhou Deliang Yin Key Laboratory of Karst Georesources and Environment(Guizhou University) Ministry of EducationGuiyang 550025China College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China Guizhou Karst Environmental Ecosystems Observation and Research Station Ministry of EducationGuiyang 550025China

Humus is often used as an organic modifier to reduce the bioaccumulation of heavy metals in plants, but the effects of different humus components from different sources on the fate of mercury(Hg) in paddy fields are still unclear. Here, fulvic acid(FA) and humic acid(HA) extracted from composted straw(CS), composted cow dung(CCD), peat soil(PM) and lignite coal(LC) were used to understand their effects on the methylation and bioaccumulation of Hg in paddy soil by pot experiments. Amendments of both FA and HA largely increased the abundance of Hg-methylating microbes and low-molecular-weight organic matters(e.g, cysteine) in paddy soil. They were also found to change the aromaticity, molecular size and Chromophoric DOM concentration of DOM, and resulted in heterogeneous effects on migration and transformation of Hg. All the FA-amended treatments increased the mobility and methylation of Hg in soil and its absorption in roots. Nevertheless, FA from different sources have heterogeneous effects on transport of Hg between rice tissues. FA-CCD and FA-PM promoted the translocation of Me Hg from roots to rice grains by 32.95% and 41.12%, while FA-CS and FA-LC significantly inhibited the translocation of inorganic Hg(IHg) by 52.65% and 66.06% and of Me Hg by 46.65% and 36.23%, respectively. In contrast, all HA-amended treatments reduced the mobility of soil Hg, but promoted Hg methylation in soil. Among which, HA-CCD and HA-PM promoted the translocation of Me Hg in rice tissues by 88.95% and 64.10%, while its accumulation in rice grains by 28.43% and 28.69%, respectively. In general, the application of some FA and HA as organic modifiers to reduce Hg bioaccumulation in rice is not feasible.

关键词： Humic acid Fulvic acid Methylmercury Accumulation Rice