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Intraband Dynamics and Terahertz Emission in Biased GaAs/In_(0.53)Ga_(0.47)As Semiconductor Superlattices

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Communications in Theoretical Physics 2009年第12期52卷 1134-1138页

作者： li min MI xian-Wu College of Physics Science and Information Engineering Jishou University Jishou 416000 China

Using an excitonic basis, we investigate the intraband polarization, optical absorption spectra, and terahertzemission of semiconductor superlattice with the density matrix theory. The excitonic Bloch oscillation is driven by thedc and ac electric fields. The slow variation in the intraband polarization depends on the ac electric field frequency. Theintraband polarization increases when the ac electric field frequency is below the Bloch frequency. When the ac electricfield frequency is above the Bloch frequency, the intraband polarization downwards and its intensity decreases. Thesatellite structures in the optical absorption spectra are presented. Due to excitonic dynamic localization, the emissionlines of terahertz shift in different ac electric field and dc electric field.

关键词： semiconductor superlattices terahertz optical spectra excitons

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氮磷钾配施对茉莉花产量及花汛期的影响

中国土壤与肥料 2024年第3期 121-128页

作者：李先民李琴黄展文孙明艳苏群卢家仕卜朝阳李春牛广西农业科学院花卉研究所广西南宁530007 广西农业科学院农业资源与环境研究所广西南宁530007

为了探寻氮磷钾配施最佳方案,为茉莉花科学施肥提供参考,选择立地条件具有区域代表性的地块为试验地,以试验地原有种植的树龄15年的广西壮族自治区横州市主栽品种横州市双瓣茉莉为供试材料,采用“3414”试验设计开展施肥效应试验,研究... 详细信息

为了探寻氮磷钾配施最佳方案,为茉莉花科学施肥提供参考,选择立地条件具有区域代表性的地块为试验地,以试验地原有种植的树龄15年的广西壮族自治区横州市主栽品种横州市双瓣茉莉为供试材料,采用“3414”试验设计开展施肥效应试验,研究氮磷钾配施对横州市茉莉花产量及花汛的影响,以明晰横州市茉莉花种植区域环境条件下鲜花产量对氮磷钾的需求差异,为茉莉花科学施肥及鲜花增产提供理论依据。结果表明:(1)广西横州市茉莉花种植试验地的土壤养分对横县双瓣茉莉生产而言,速效氮含量过剩,而有效磷和速效钾处于中等偏低水平;(2)在氮磷钾3种肥料的互作效应中,磷肥和钾肥的互作效应最高,其次为氮磷钾肥和氮钾肥的互作效应;(3)不同的施肥处理的茉莉花日产量消长同步,不同氮磷钾配施对茉莉花花汛期的影响不显著;(4)在茉莉花的稳定花期(6—9月)中,各月均有花汛期出现,其中,7月平均日产量最高,8月平均日产量最稳定;(5)氮磷钾配施对茉莉花产量有显著影响,影响由大到小为磷肥>钾肥>氮肥;(6)本研究中,三元二次方程拟合不成功,一元二次方程方面仅有N的效应方程拟合成功,P、K的效应方程均拟合失败,而在二元二次方程中,NP、NK、PK的3个效应方程均拟合成功;对拟合成功的方程进行求解,排除实际操作中无法达到的施肥量,综合考虑试验地土壤速效氮含量过剩及减少种植户的投资成本等因素,推荐施肥方式及施肥量为磷肥393.64 kg/hm^(2),钾肥381.59 kg/hm^(2)。

关键词：茉莉花肥料配施 “3414”试验产量花汛期

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Theoretical Design of Defects as a Driving Force for Ion Transport in li3OBr Solid Electrolyte

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Energy & Environmental Materials 2024年第3期7卷 147-157页

作者： Xingyun Luo Yanlu li xian Zhao State Key Lab of Crystal Materials and Institute of Crystal Materials Shandong University Center for Optics Research and Engineering Shandong University

Due to ever-increasing concerns about safety issues in using li ionic batteries,solid electrolytes have extensively *** li-rich antiperovskite li3OBr has been considered as a promising solid electrolyte candidate,but it still suffers challenges to achieve a high ionic conductivity owing to the high intrinsic symmetry of the crystal ***,we presented a design strategy that introduces various point defects and grain boundaries to break the high lattice symmetry of li3OBr crystal,and their effect and microscopic mechanism of promoting the migration of li-ion were explored *** has been found that liiare the dominant defects responsible for the fast li-ion diffusion in bulk li3OBr and its surface,but they are easily trapped by the grain boundaries,leading to the annihilating of the Frenkel defect pair V'li+li,and thus limits the V'lidiffusion at the grain *** VBrdefect near the grain boundaries can effectively drive V'liacross the grain boundary,thereby converting the carrier of li+migration from li,in the bulk and surface to V'liat the grain boundary,and thus improving the ionic conductivity in the whole li3OBr *** work provides a comprehensive insight into the li+transport and conduction mechanism in the li3OBr *** opens a new way of improving the conductivity for all-solid-state li electrolyte material through the defect design.

关键词： defects density functional theory ionic migration solid electrolyte

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基于机器学习的滤棒圆周模型

价值工程 2024年第18期43卷 92-94页

作者：陈慧媛李敏娴张羽茜华鸣宇李依璇红云红河烟草(集团)有限责任公司昆明650000

卷烟圆周是滤棒的重要物理指标之一。它能直接影响卷烟的消费者体验。为了更好地确保生产滤棒圆周的一致性,本文利用工业大数据,考虑到变量之间可能存在的非线性关系,选择了随机森林的机器学习方法对影响滤棒圆周因素进行了研究。结果表... 详细信息

卷烟圆周是滤棒的重要物理指标之一。它能直接影响卷烟的消费者体验。为了更好地确保生产滤棒圆周的一致性,本文利用工业大数据,考虑到变量之间可能存在的非线性关系,选择了随机森林的机器学习方法对影响滤棒圆周因素进行了研究。结果表明,经过变量选择后,模型的精准度由77.92%提高到了84.4%,滤棒圆周主要受冷却棒位置、吸阻高低、吸阻稳定性、丝束填充量、开松辊速比影响。

关键词：滤棒圆周工业大数据变量选择机器学习随机森林

Theoretical Study on the Nitrogen-rich Derivatives Based on 1,2,4-Triazole and 1,2,3-Triazole Rings:an Extended Family of Power Performance Energetic Materials

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Chinese Journal of Structural Chemistry 2021年第9期40卷 1113-1121,1107页

作者： JIA Jing-xian PANG Yu YANG Jing li min-xian MENG xiang-Jun GAO Xiao-Zhen liU li-Hua LRJ Meng-Na Department of Chemistry Tangshan Normal CollegeTangshan 063000China Yangquan Municipal Key Laboratory of Quantum Manipulation Shanxi Institute of TechnologyYangquan 045000China

The geometric and electronic structures of the derivatives of 4-nitro-5-(5-nitroimino-1,2,4-triazol-3-yl)-2H-1,2,3-triazolate(named A~J)are explored employing density functional theory(DFT)calculations at the B3LYP/6-311G^(**)level of *** on the optimized molecular structures,the heats of formation(HOF)are obtained,and the electronic properties,density and molecular sensitivity by characteristic heights(H_(50))are ***,the detonation performances(detonation velocity,detonation pressure)are estimated via Kamlet-Jacobs(K-J)*** B(H50=29.4 cm,ρ=1.91 g/cm^(3),Q=1563.04 cal/g,P=36.05 GPa,D=8.95 km/s)and H(H_(50)=31.9 cm,ρ=1.80 g/cm^(3),Q=1610.09 cal/g,P=37.31 GPa,D=9.12 km/s)have positive HOFs and remarkable insensitivity and good detonation performance,strongly suggesting them as the acceptable new-type *** initiating power surpasses conventional primary explosives,such as *** outstanding detonation power of compounds B and H contributes to its future prospects as a promising green primary explosive.

关键词： 4-nitro-5-(5-nitroimino-1,2,4-triazol-3-yl)-2H-1,2,3-triazolate high energy density materials density functional theory explosive

Molecular Design and Property Prediction of High Density 4-Nitro-5-(5-nitro-1,2,4-triazol-3-yl)-2H-1,2,3-triazolate Derivatives as the Potential High Energy Explosives

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Chinese Journal of Structural Chemistry 2022年第2期41卷 123-131,I0011页

作者： YANG Jing PANG Yu li min-xian YANG Ge-Fei JIA Jing-xian MENG xiang-Jun liU li-Hua YANG Xiao-Chun GAO Xiao-Zhen Department of Chemistry Tangshan Normal CollegeTangshan 063000China School of Chemical Engineering and light Industry Guangdong University of TechnologyGuangzhou 510006China Yangquan Municipal Key Laboratory of Quantum Manipulation Shanxi Institute of TechnologyYangquan 045000China

To search for potential energetic materials with large energy density and acceptable thermodynamics and kinetics stability,twelve derivatives of 4-nitro-5-(5-nitro-1,2,4-triazol-3-yl)-2H-1,2,3-triazolate(named A~L)are designed and analyzed by using density functional theory(DFT)calculations at the B3LYP/6-311G**level of *** molecular heats of formation(HOF),electronic structures,impact sensitivity(H_(50)),oxygen balance(OB)and density(ρ)are investigated by isodesmic reaction method and physicochemical ***,the detonation velocity(D)and detonation pressure(P)are calculated to study the detonation performance by Kamlet-Jacobs(K-J)*** results show that new molecule J(H_(50)=36.9 cm,ρ=1.90g/cm^(3),Q=1912.46 cal/g,P=37.82 GPa,D=9.22 km/s,OB=0.00),compound A(H_(50)=27.9 cm,ρ=1.93 g/cm^(3),Q=1612.93 cal/g,P=38.90 GPa,D=9.19 km/s)and compound H(H_(50)=37.3 cm,ρ=1.97 g/cm^(3),Q=1505.06cal/g,P=37.20 GPa,D=9.01 km/s)present promising effects that are far better RDX and HMX as the high energy density *** calculations can provide useful information for the molecular synthesis of novel high energy density materials.

关键词： 4-nitro-5-(5-nitro-1,2,4-triazol-3-yl)-2H-1,2,3-triazolate energetic materials density functional theory explosive

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混联式电动汽车动力系统的建模和性能仿真

长安大学学报（自然科学版） 2014年第5期34卷 161-168页

作者：李宪民长安大学汽车学院陕西西安710064

为了更好地评价电动汽车各种性能,在对传统轿车驱动系统的方案和传递路线进行设计和动力源优化匹配的基础上,依据整车结构,通过对传动系统进行设计、优化和匹配的同时,对电机组件进行选型与匹配,利用Matlab/Simulink软件,对混合动力电... 详细信息

为了更好地评价电动汽车各种性能,在对传统轿车驱动系统的方案和传递路线进行设计和动力源优化匹配的基础上,依据整车结构,通过对传动系统进行设计、优化和匹配的同时,对电机组件进行选型与匹配,利用Matlab/Simulink软件,对混合动力电动汽车的传动系统和控制策略进行仿真建模,在CYC_UDDS和CYC_1015循环工况下对整车动力性和排放性能进行了仿真研究。结果表明:在保证原有车型动力性的前提下,节油率分别可以达到24%和30%,排放性能也得到了极大的改善。这对中国开展电动汽车仿真研究具有一定参考作用。

关键词：汽车工程混合动力车电动汽车传动系统制动能量回收建模与仿真

不同变形状态下变物性梯度功能材料板瞬态热应力

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工程力学 2006年第3期23卷 49-55,92页

作者：许杨健李现敏文献民河北工程大学土木工程学院河北邯郸056038 浙江科技学院土木系杭州310023

用非线性有限元法分析了由ZrO2和Ti-6Al-4V组成的变物性梯度功能材料板的对流换热瞬态热应力问题,与已有文献比较检验了方法的正确性,给出了该材料板在不同变形状态下的瞬态热应力分布,并与常物性时的结果进行了比较。结果表明:无限自... 详细信息

用非线性有限元法分析了由ZrO2和Ti-6Al-4V组成的变物性梯度功能材料板的对流换热瞬态热应力问题,与已有文献比较检验了方法的正确性,给出了该材料板在不同变形状态下的瞬态热应力分布,并与常物性时的结果进行了比较。结果表明:无限自由长板内的热应力最小;当无限长板只能伸长、不能弯曲时,板内瞬态拉应力最大;当无限长板伸长、弯曲受限时,板内的瞬态压应力最大;考虑变物性时的最大拉应力比常物性减小48.9%,最大压应力减小39.6%;此外,对流换热系数的变化对不同变形状态下该变物性材料板瞬态热应力场的影响显著。此结果为该材料的设计和应用提供了准确的理论计算依据。

关键词：梯度功能材料板瞬态热应力非线性有限元法变物性变形状态对流换热边界

Evaluation of transmission risk of respiratory particles under different ventilation strategies in an elevator

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Building Simulation 2024年第5期17卷 771-784页

作者： liangyu Zhu xian li Bujin Feng Fan liu School of Civil Engineering and Architecture Linyi UniversityLinyi276000China College of Agriculture Shandong Agricultural UniversityTaian271018China School of Environment and Architecture University of Shanghai for Science and TechnologyShanghai200093China

People in elevators are at risk of respiratory infection because the elevator cabin is crowded and has poor *** exhaled particles may be inhaled by the susceptible person,deposited on the surface and suspended in the elevator,which can result in direct and indirect ***,whether the air vent designs adopted in the elevator can effectively reduce the transmission risk of respiratory particles remains *** this study,the dispersion of particles under four common ventilation strategies used in the commercial elevator was investigated by proven computational fluid dynamics(CFD)*** flow field was simulated with the RNG κ-ξ turbulence model and the Lagrangian method was adopted to track particle *** effects of air vent layout and airflow rate on particle transmission were *** found that more than 50% of exhaled particles(average value)were suspended in the cabin and difficult to discharge under the investigated ventilation *** deposited fraction of particles on the susceptible person reached up to 39.14% for infiltration ventilation,which led to a high risk of contact *** the ventilation rate could not significantly reduce the inhalation proportion of particles due to the poor airflow distribution inside the elevator.A more proper ventilation strategy should be explored for the elevator to control transmission risk.

关键词： particle dispersion transmission risk elevator ventilation strategy computational fluid dynamics(CFD)