Role of excited states in the elliptically polarized harmonic generation

We theoretically investigate the contribution of the excited state to the ellipticity of the harmonics from H＋ at different orientation angles irradiated by a linearly polarized laser pulse. It is found that the first excited state has a significant influence to the ellipticity of the harmonics, and the contribution of higher excited states to the ellipticity can be neglected. Moreover, the conclusion is not dependent on the laser intensity.     

Enhancement of ferromagnetic resonance in Al203-doped CozFeAI Heusler alloy film prepared by oblique sputtering

Large and variable in-plane uniaxial magnetic anisotropy in a nanocrystalline （Co2FeA1）97.8（Al2O3）2.2 soft magnetic thin film is obtained by an oblique sputtering method without being induced by magnetic field or post anneaiing. The in-plane uniaxiai magnetic anisotropy varies from 50 Oe to 180 Oe （1 Oe=79.5775 A·m-1） by adjusting the sample＇s position. As a result, the ferromagnetic resonance frequency of the film increases from 1.9 GHz to 3.75 GHz.     

卤素氟化物ClFO3的结构与性能的理论研究

卤素氟化物是一类反应活性很强的物质,在诸多领域有重要应用。本文采用量子化学密度泛函理论（DFT）B3LYP/6-31G(2df)方法,对卤素氟化物ClFO3的七种异构体进行了几何优化和振动频率分析,结果表明它们均对应于势能面上的稳定构型。这七种异构体中,Cl原子作为中心原子,与1个F原子和3个O原子直接成键形成的分子结构能量最低,为最稳定结构。根据统计热力学原理,计算了标题物的标准热力学函数,包括摩尔热容（Cop,m）、摩尔熵（Som）和摩尔焓（Hom）。理论计算所得结构参数和与热力学函数均与文献报道的实验值相符,说明了所用理论方法的可靠性。借助于原子化反应和生成反应计算了其生成焓及其与甲烷和水反应的热效应。在DFT优化分子结构的基础上,采用力场方法得到ClFO3的最可能堆积方式属于Pbca空间群,进一步采用DFT GGA-RPBE方法优化其晶体结构,并计算能带结构和态密度,发现其带隙较宽（4.61eV）,表明其具有较好的稳定性。在Fermi能级附近,ClFO3晶体中的导带主要来自于O和F原子的2p轨道的贡献,而价带主要来自于Cl原子的2p轨道的贡献。     

一类双氯芬酸类似物环氧合酶抑制剂作用模式的理论研究

基于 1PXX 晶体结构以及以晶体中双氯芬酸 DIF701 为模版的双氯芬酸类似物2型环氧合酶(COX-2) 抑制剂的结构,利用药效团和自组织分子力场分析方法,探讨了 COX-2 与抑制剂的相互作用模式。建立了双氯芬酸药效团模型和 COX-2 抑制剂三维定量构效关系模型,并且两种方法所得的模型吻合;确定的 COX-2 与抑制剂的作用模式,可以指导抑制剂的设计,用于开发抗炎药物。     

合成绿原酸内生细菌的筛选、鉴定及发酵培养基的初步优化

目前绿原酸的主要来源为天然植物中提取,但天然植物中绿原酸含量较低且提取工艺复杂,导致绿原酸生产效率较低,因此有必要寻找新的、高效的制备绿原酸方法.本研究以金银花叶、红薯叶、薄荷叶、蒲公英叶和杜仲叶为材料,采用组织块法开展合成绿原酸的内生菌分离筛选,并利用高效液相色谱(HPLC)对筛选出内生菌的发酵产物进行分析,最终从植...     

9-乙酰氧基乙基-6-烷氨基-2-烷硫基嘌呤的合成及抗血小板凝集活性评估

以2-氨基-6-氯嘌呤(1)为原料,与2-溴乙基乙酸酯反应得到9-乙酰氧基乙基-2-氨基-6-氯嘌呤(2);2经重氮-烷硫化得到9-乙酰氧基乙基-2-烷硫基-6-氯嘌呤(3);3经胺解反应得到14个未见报道的9-乙酰氧基乙基-6-烷氨基-2-烷硫基嘌呤化合物4.这些化合物的结构经IR,1H NMR,13C NMR及HRMS得到表征,同时进行了抗血小板凝集活性测试.     

核实验数据获取系统中的触发信号预处理

简要介绍了在核物理实验数据获取系统中,用FPGA芯片和VHDL语言实现对事件触发信号的预处理。阐述了在核物理实验数据获取系统中对事件触发信号的一般要求; 结合60Co伽马谱测量实验,介绍了基于一套自主研发的数据获取系统中触发信号的预处理,并给出了用VHDL语言实现该触发信号预处理的思想、仿真时序图和实验结果。该方法通过实验验证,证明切实可行,灵活性强。     

High-order harmonic generation with a two-color laser pulse

We theoretically investigate the electron dynamics of the high-order harmonics generation process by combining a near-infrared 800 nm driving pulse with a mid-infrared 2000 nm control field.We also investigate the emission time of harmonics using time-frequency analysis to illustrate the physical mechanisms of high-order harmonic generation.We calculate the ionization rate using the Ammosov-Delone-Krainov model and interpret the variations in harmonic intensity for different control field strengths and delays.We find that the width of the harmonic plateau can be extended when the control electric field is added,and a supercontinuum from 198 to 435 eV is generated,from which an isolated 61-as pulse can be directly obtained.     

基于AHP及Logit回归的新能源汽车市场预测模型

根据消费者效用极大化原理,利用层次分析法,分析中国消费者购买新能源汽车的成本、可靠性、动力性、形象、安全性和便利性因素的权重;通过对欧、美、日新能源汽车乘用车市场份额与消费者效用的Logit回归分析,构建基本、一般和激进三种政府规制场景下的中国新能源汽车乘用车市场份额的预测模型.结果表明,新能源汽车市场的发展与政府规制有密切的关系.到2015年,在基本、一般和激进三种场景下,新能源汽车分别占14%,23%,36%左右;混合动力和纯电动汽车是市场份额最大的两种车型;燃料电池汽车市场份额最小,为0.25%～0.85%.     

Interaction of intense laser pulses with hydrogen atomic clusters

The interaction between intense femtosecond laser pulses and hydrogen atomic clusters is studied by a simplified Coulomb explosion model. The dependences of average proton kinetic energy on cluster size, pulse duration, laser intensity and wavelength are studied respectively. The calculated results indicate that the irradiation of a femtosecond laser of longer wavelength on hydrogen atomic clusters may be a simple, economical way to produce highly kinetic hydrogen ions. The phenomenon suggests that the irradiation of femtosecond laser of longer wavelength on deuterium atomic clusters may be easier than that of shorter wavelength to drive nuclear fusion reactions. The product of the laser intensity and the squared laser wavelength needed to make proton energy saturated as a function of the squared cluster radius is also investigated. The proton energy distribution calculated is also shown and compared with the experimental data. Our results are in agreement with the experimental results fairly well.