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Search Results: 1 - 10 of 38544 matches for " 段素青 "
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Dynamical properties of two-band superlattices with strong interband coupling in real space under the action of ac and dc-ac fields
,王志刚,赵宪庚
中国物理 B , 2003,
Abstract: Within a two-band tight-binding model driven by ac and dc-ac electric fields, using numerical methods, we investigate the dynamics of electrons and the quasi-energy spectrum of the system with strong interband coupling in real space. We find that when the bandwidth is suppressed to a value much smaller than the field frequency, the dynamical localization can exist in the system. The corresponding regions are found for the occurrence of dynamical localization in the parameter space.
Mo高压熔化的分子动力学模拟
张弓木,刘海风,
高压物理学报 , 2008, DOI: 10.11858/gywlxb.2008.01.012
Abstract: 采用第一原理方法计算了钼在零温下的结构,表明钼在500GPa以下一直保持bcc结构(常温),与实验一致。在零压附近计算了E-V关系,利用Murnaghan物态方程拟合得到了零压体积及其模量,与实验结果符合得很好。采用第一原理分子动力学模拟了钼的高压熔化性质。采用NVT系综计算了128个原子的系统,初始构形为bcc结构,体积分别为0.01548、0.01219、0.01098、0.00984、0.00910nm3/atom,计算了几个温度点,拟合得到了熔化曲线,熔化温度明显高于金刚石压砧(DAC)实验结果;将初始构形改变为fcc结构,模拟其熔化特性,得到的熔化温度明显下降,与激光加载DAC实验结果一致,认为可能的原因是钼熔化后形成的液体结构类似于fcc结构,而不是常态时的bcc结构。
运用微机研究重陀螺的定点运动
,程达三
力学与实践 , 1994, DOI: 10.6052/1000-0992-1994-150
Abstract: 运用微机研究重陀螺的定点运动段素青,程达三(太原工业大学材料工程学院,太原030021)重陀螺作定点运动时,其对称轴在以固定点为中心的球面上画出的轨迹直观地描绘出陀螺的进动和章动过程,共有3种类型,通常在理论力学教材中 ̄[1]只是定性地给出了这3种形...
单轴应变驱动铁bcc—hcp相转变的微观模拟
邵建立,何安民,,王裴,秦承森
物理学报 , 2010,
Abstract: 用分子动力学方法模拟了沿〈001〉晶向应变加载和卸载情况下单晶铁中体心立方(bcc)与六方密排(hcp)结构的相互转变,分析了相变的可逆性和微结构演化特征.微观应力的变化显示样品具有超弹性性质,而温度变化表明在相变和逆相变过程中均出现放热现象.相变起始于爆发式均匀形核,晶核由块状颗粒迅速生长为沿{011}晶面的片状分层结构; 而卸载逆相变则从形核开始就呈现片状形态,且相界面晶面指数与加载相变完全一致,表现出形态记忆效应.在两hcp晶核生长的交界面易形成面心立方(fcc)堆垛层错. fcc通过在hcp晶粒内
Melting and Grüneisen parameters of NaCl at high pressure
陈其峰,蔡灵仓,,陈栋泉
中国物理 B , 2004,
Abstract: The Buckingham potential has been employed to simulate the melting and thermodynamic parameters of sodium chloride (NaCl) using the molecular dynamics (MD) method. The constant-volume heat capacity and Grüneisen parameters have been obtained in a wide range of temperatures. The calculated thermodynamic parameters are found to be in good agreement with the available experimental data. The NaCl melting simulations appear to validate the interpretation of superheating of the solid in the one-phase MD simulations. The melting curve of NaCl is compared with the experiments and other calculations at pressure 0-30GPa range.
量子级联激光器生热的电路模型分析
宿非凡,纪幸辰,姜仁志,王健,吕燕伍,
量子电子学报 , 2013,
Abstract: 通过分析量子级联激光器(QCL)中各量子阱的生热及阱间的热流输运情况,得到它的热输运方程,以此为基础类比电路理论建立了等效电路模型,利用matlab和EWB512分别进行理论与电路模拟,得到了它的生热特性,并对可能影响它的生热特性的一些因素进行了分析。
Effect of electron-phonon interactions on dynamical localization of semiconductor superlattices
电声子相互作用对半导体超晶格动力学局域化的影响

Wang Zhi-Gang,Duan Su-Qing,Zhao Xian-Geng,
王志刚
,,赵宪庚

中国物理 B , 2005,
Abstract: 本文用单带模型分别研究了直流外场和交流外场作用下,电声子相互作用对半导体超晶格的动力学局域化性质的影响。结果表明:电声子相互作用会破坏电子的动力学局域化。对同一声子频率,电声子相互作用的强度越大,电子越快被散射;当声子频率等于直流场的布洛赫频率或交流场频率时,初始局域在某一格点的电子被迅速地散射到其他格点上去,亦即光声子共振场会严重破坏电子的动力学局域化性质。
Effect of external noise on the dynamical localization of two coupling electrons in quantum dot array
He An-Min,Duan Su-Qing,Zhao Xian-Geng,
何安民
,,赵宪庚

中国物理 B , 2005,
Abstract: The effect of external noise, which is characterized by an Ornstein--Uhlenbeck process, on the dynamical localization of two coupling electrons in a quantum dot array under the action of an ac electric field is studied. A numerical solution of the stochastic equations is obtained by averaging over stochastic trajectories. The results show that the external noise may destroy the dynamical localization, but the anti-noise capacity of the system is stronger when the two electrons are localized at the ends of the quantum dot array.
7种秋海棠叶片斑纹结构及遗传特性分析
杜文文,,,马璐琳,,贾文杰,王祥宁,崔光芬
- , 2018,
Abstract: 以7种(品种)秋海棠为材料,观察叶片斑区和非斑区组织结构、测定叶绿素含量及叶绿素荧光参数Fv/Fm值,分析叶片斑纹的形成原因及银点秋海棠点状斑的遗传特性。结果显示:(1)银点秋海棠、铺地秋海棠、假厚叶秋海棠、‘皮卡’和‘非洲丛林’叶片斑区的上表皮细胞与栅栏组织细胞间存在空隙,非斑区则没有空隙,彩纹秋海棠和‘虎斑’的斑区与非斑区上表皮细胞和栅栏组织细胞间均紧密相连。(2)7种(品种)秋海棠叶片斑区和非斑区都具有完整的叶绿体超微结构,类囊体膜丰富,基质和基粒片层清晰;银点秋海棠、假厚叶秋海棠、‘皮卡’和‘非洲丛林’斑区的叶绿素a、b及总叶绿素含量均低于非斑区,而铺地秋海棠斑区和非斑区差别不大;除假厚叶秋海棠的斑区叶绿素荧光参数Fv/Fm值小于非斑区外,其余6种秋海棠均为斑区高于非斑区。(3)银点秋海棠与斑种类杂交,杂交后代叶片有斑和斑的植株约为1∶1,而其自交后代中有斑和斑的植株比例近3∶1。研究发现,银点秋海棠、铺地秋海棠、假厚叶秋海棠、‘皮卡’和‘非洲丛林’的叶斑属于空隙结构型,彩纹秋海棠和‘虎斑’叶斑属于色素型。银点秋海棠点状叶斑与斑是1对可遗传的相对性状,白色点状斑为显性性状。
人工海水和标准海水

海洋科学 , 1978,
Abstract:
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