变频率光场与二能级原子的相互作用：双光子过程

研究了二能级原子与单模电磁场相互作用时的双光子过程,主要考虑了在相干态初始条件下场频率发生变化时的情况,讨论了场频率随时间作正弦缓慢变化对原子布居数反转、光场压缩与原子压缩等特性的影响.结果显示,场频率的改变将使得原子布居数反转的崩塌回复周期增大,回复值减小,而光场及原子压缩效应减弱. 关键词： 布居数反转 光场压缩 原子压缩 双光子过程     

CdTe太阳电池中起因于Cu的深能级

在CdTe太阳电池中,易引入并形成Cu深能级中心. 本文采用深能级瞬态谱测试法研究了ZnTe背接触和石墨背接触CdTe太阳电池的部分深能级中心. 研究中运用密度泛函相关理论,分析闪锌矿结构CdTe,Cd空位体系和掺Cu体系的电子态密度,计算得出T_d场和C_3v场下Cu²⁺ d轨道的分裂情况. 计算结果表明,CdTe太阳电池中的E_v+0206 eV和E_v+0122 eV两个深中心来源于Cu替代Cd原子. 计算结果还表明,掺入Cu可降低CdTe体系能量. 关键词： 深能级瞬态谱 第一性原理 CdTe Cu杂质     

Focusing of Time Reversal Lamb Waves and Its Applications in Structural Health Monitoring

The focusing of time reversal acoustic fields for dispersive and multimodal Lamb waves is theoretically investigated and experimentally verified. It is demonstrated that the time reversal Lamb wave signal will reach the maximum amplitude when the observation point is located at the damage location. Based on the time reversal focusing theory, a damage imaging method is proposed for structural health monitoring using Lamb waves. The experiments employ a transducer network consisting of four piezoelectric transducers as actuators and as well sensors for excitation and measurement of Lamb waves. The results show that this method is able to accurately predict damage location and provides an estimation of the possible area even for damage close to one of the transducers or even slightly outside the transducer network.     

Generalized Harmonic Oscillator and the SchrSdinger Equation with Position-Dependent Mass

We study the generalized harmonic oscillator that has both the position-dependent mass and the potential depending on the form of mass function in a more general framework. The explicit expressions of the eigenvalue and eigenfunction for such a system are given, they have the same forms as those for the usual harmonic oscillator with constant mass. The coherent state and its properties corresponding effective potentials for several mass functions, for the system with PDM are also discussed. We give the the systems with such potentials are isospectral to the usual harmonic oscillator.     

刚竹毒蛾危害下的毛竹叶片光谱特征及虫害等级检测研究

探讨刚竹毒蛾危害下的毛竹叶片光谱特征可为建立竹林生态安全监测体系提供重要的理论指导.相比于传统的多光谱数据,高光谱遥感能够准确探测不同刚竹毒蛾危害等级间寄主光谱的细微变化.然而,当前有关此方面的研究甚少,其寄主的光谱变化机理还有待进一步总结.为此,基于实测的552条竹叶光谱,分析了健康、受刚竹毒蛾危害、小年叶片之间的光...     

分支通道内液-液自发渗吸规律研究

自发渗吸过程中两相界面在分支通道内的破裂和汇合为强非稳态过程, 难以用经典理论及常规数值计算方法准确描述。本文采用格子玻尔兹曼方法研究孔隙结构分支通道基本单元内的液-液自发渗吸行为, 对比出入口通道大小、两相黏度差异对液-液自发渗吸行为的影响。入口通道的大小对两相界面破裂进入分支通道内的竞争自发渗吸行为起控制作用, 而两相流体黏度控制了自发渗吸整体行为。本研究为复杂孔隙结构内液-液自发渗吸行为定量表征提供研究基础。     

尖海龙提取物抗癌作用的研究

制备尖海龙提取物,再将其分别作用于Hela,SK-RB-3细胞系,从细胞形态变化,细胞计数,集落形成率,细胞分裂指数变化观察体外药效,结果表明,尖海龙提取物可改变肿瘤的正常生活形态,又可显著抑制肿瘤细胞的增殖,降低集落形成率,减少分裂指数,从而证实尖海龙提取物具有抗癌活性,其在癌症的治疗与预防方面具有实用价值。     

Collective expansion and hadronization in high energy heavy ion collision experiments

An overview of research status of soft physics in high energy heavy-ion collision experiments and recent experimental results are presented.     

Linear analysis of degree correlations in complex networks

Many real-world networks such as the protein–protein interaction networks and metabolic networks often display nontrivial correlations between degrees of vertices connected by edges. Here, we analyse the statistical methods used usually to describe the degree correlation in the networks, and analytically give linear relation in the degree correlation. It provides a simple and interesting perspective on the analysis of the degree correlation in networks, which is usefully complementary to the existing methods for degree correlation in networks. Especially, the slope in the linear relation corresponds exactly to the degree correlation coefficient in networks, meaning that it can not only characterize the level of degree correlation in networks, but also reflects the speed that the average nearest neighbours’ degree varies with the vertex degree. Finally, we applied our results to several real-world networks, validating the conclusions of the linear analysis of degree correlation. We hope that the work in this paper can be helpful for further understanding the degree correlation in complex networks.     

纳米氧化锌中三光子吸收与倍频效应致光辐射特性

为研究强光激励下纳米氧化锌发光机制,以气相传输法制备的冠状样品为对象,室温下以1 100nm与1 150 nm脉冲激光以及350 nm氙灯对其进行激励,观测光致发光谱.根据光强关系和强场与物质作用的三阶微扰理论,认为1 100,1 150 nm激光激励下的样品的紫外与可见光波段的辐射机理分别归因于样品中三光子吸收和二次谐波效应.同时,基于激子非弹性碰撞复合机制,对紫外辐射的红移现象进行了分析.