氙灯泵浦新型晶体Nd∶S－VAP调Q激光器腔内倍频研究

采用氙灯泵浦晶体Ｎｄ∶Ｓ－ＶＡＰ，ＫＴＰ晶体腔内倍频，实现了Ｎｄ∶Ｓ－ＶＡＰ晶体０．５３２５μｍ绿光激光ＢＤＮ染料片调Ｑ运转。测量了输出绿光激光的特性及不同腔长和染料片小信号透过率情况下的输出能量及脉冲宽度，给出了染料片调Ｑ腔内倍频的耦合波方程组，数值求解方程组，所得的理论数据与实验结果很好地相符     

Forward-backward multiplicity correlations of target fragments in nucleus-emulsion collisions at a few hundred MeV/u

The forward-backward multiplicity and correlations of a target evaporated fragment (black track particle) and target recoiled proton (grey track particle) emitted from 150 A MeV ⁴He, 290 A MeV ¹²C, 400 A MeV ¹²C, 400 A MeV ²⁰Ne and 500 A MeV ⁵⁶Fe induced different types of nuclear emulsion target interactions are investigated. It is found that the forward and backward averaged multiplicity of a grey, black and heavily ionized track particle increases with the increase of the target size. The averaged multiplicity of a forward black track particle, backward black track particle, and backward grey track particle do not depend on the projectile size and energy, but the averaged multiplicity of a forward grey track particle increases with an increase of projectile size and energy. The backward grey track particle multiplicity distribution follows an exponential decay law and the decay constant decreases with an increase of target size. The backward-forward multiplicity correlations follow linear law which is independent of the projectile size and energy, and the saturation effect is observed in some heavy target data sets.     

单分子力谱研究活细胞上多药耐药相关蛋白1的表达

采用原子力显微镜的单分子力谱(SMFM)技术研究了多药耐药相关蛋白1(MRP1)与其抗体间的相互作用, 并考察了人舌癌细胞系TCA8113经高剂量平阳霉素(BLM)反复间歇诱导前后细胞表面MRP1的表达差异. 实验结果表明, MRP1与其抗体之间存在特异性相互作用力, 当针尖运动速率为2.5 μm/s时, 作用力大小约为(182±35) pN; 而且药物诱导后MRP1在人舌癌细胞上的表达明显增强. 本工作为了解活细胞水平上MRP1的表达提供了新方法, 有助于肿瘤细胞多药耐药性(MDR)的研究.     

纳米金颗粒增强信号的电化学生物传感器用于谷胱甘肽和半胱氨酸的检测

构建了一种高灵敏检测谷胱甘肽(GSH)和半胱氨酸(Cys)的新型电化学生物传感器. 先将富含T碱基的DNA1和DNA2探针分别修饰在金电极和纳米金颗粒(AuNPs)上, 再加入Hg²⁺, 通过形成T-Hg²⁺-T结构使AuNPs结合到金电极表面. 当加入GSH(或Cys)后, GSH(或Cys)可以竞争结合T-Hg²⁺-T结构中的Hg²⁺, 使AuNPs离开电极表面. 由于AuNPs上修饰的DNA探针能够静电吸附大量电活性物质六氨合钌(RuHex), 因此该过程可引起计时电量信号的显著变化, 据此实现了GSH(或Cys)的高灵敏检测. 该传感器的检出限达10 pmol/L, 比荧光法或比色法降低了2~3个数量级. 实验结果表明, 该传感器具有较好的选择性.     

Mg/Cd共掺杂ZnO电子结构与光学性质的第一性原理研究

采用基于密度泛函理论的第一性原理平面波超软赝势法,研究了Mg/Cd(不同的Cd浓度)共掺杂ZnO的电子结构和光学性质.研究表明:Mg/Cd共掺杂ZnO,体系的晶胞尺寸变大,但结构稳定.当Mg/Cd为1:1时,吸收边略微发生蓝移.随Cd的掺杂浓度增加,导带部分逐渐下移,禁带宽度变窄,出现红移现象.除此之外体系的吸收率和反射率也减小.说明Mg/Cd共掺杂ZnO,不仅使得体系光学谱丰富,而且透射性增强.这对实验中制备出高透射率的材料具有一定的指导意义.     

Electronic band structure of a type-II ’W’ quantum well calculated by an eight-band k·p model

In this paper, we present an investigation of type-II 'W' quantum wells for the InAs/Ga_1-xIn_xSb/AlSb family, where 'W' denotes the conduction profile of the material. We focus our attention on using the eight-band k?p model to calculate the band structures within the framework of finite element method. For the sake of clarity, the simulation in this paper is simplified and based on only one period---AlSb/InAs/Ga_1-xIn_xSb/InAs/AlSb. The obtained numerical results include the energy levels and wavefunctions of carriers. We discuss the variations of the electronic properties by changing several important parameters, such as the thickness of either InAs or Ga_1-xIn_xSb layer and the alloy composition in Ga_1-xIn_xSb separately. In the last part, in order to compare the eight-band k?p model, we recalculate the conduction bands of the 'W' structure using the one-band k?p model and then discuss the difference between the two results, showing that conduction bands are strongly coupled with valence bands in the narrow band gap structure. The in-plane energy dispersions, which illustrate the suppression of the Auger recombination process, are also obtained.     

LD抽运Nd∶YVO_4自喇曼倍频黄光激光器

报道了LD抽运的自喇曼c切Nd∶YVO4调Q腔内倍频黄光激光器.Nd∶YVO4晶体同时作为激光介质和喇曼晶体,通过声光调Q技术,产生了1178.7nm的喇曼激光,经过KTP腔内倍频,输出589.4nm黄光.测量了平均输出功率随抽运功率和脉冲重复率的变化.典型的1066.7nm基频光、1178.7nm喇曼光和589.4nm倍频光的脉冲宽度分别为24.9ns、11.2ns和6.8ns.在脉冲重复率为15kHz,抽运功率为7.56W时,产生了平均功率为151mW的589.4nm光的输出.     

GaAs被动调Q Nd:YAG激光器激光特性的研究

报道了用半导体材料 Ga As实现氙灯抽运 Nd:YAG激光器的被动调 Q运转 ,测量了激光器的阈值、脉冲宽度和输出能量。从 Ga As的能级结构出发 ,理论上研究了 Ga As材料的饱和吸收原理 ,建立了调 Q激光器速率方程并给出了数值解 ,对理论结果与实验结果进行了比较和讨论。     

路的字典积的邻和可区别边染色

图G的正常[k]-边染色σ是指颜色集合为[k]={1,2,…,k}的G的一个正常边染色.用w_σ（x）表示顶点x关联边的颜色之和,即w_σ（x）=∑_e∋x σ（e）,并称w_σ（x）关于σ的权.图G的k-邻和可区别边染色是指相邻顶点具有不同权的正常[k]-边染色,最小的k值称为G的邻和可区别边色数,记为χ'_∑（G）.现得到了路P_n与简单连通图H的字典积P_n[H]的邻和可区别边色数的精确值,其中H分别为正则第一类图、路、完全图的补图.     

有限空间中经典场的正则量子化

从离散的角度研究带边界的1+1维经典标量场和Dirac场的正则量子化问题. 与以往不同的是, 这里将时间和空间两个变量同时进行变步长的离散, 应用变步长离散的变分原理, 得到离散形式的运动方程、边界条件和能量守恒的表达式. 然后, 根据Dirac理论, 将边界条件当作初级约束, 将边界条件和内在约束统一处理. 研究表明, 采用此方法, 不仅在每个离散的时空格点上能够建立起Dirac括号, 从而可以完成该模型的正则量子化;而且, 该方法还保持了离散情况下的能量守恒.