碱蓝6B共振光散射法检测DNA

研究了碱蓝 6B与脱氧核糖核酸在酸性条件下共振光散射特征 ,考察了影响因素和最佳反应条件 ,建立了一种测定纳克级DNA的方法。在四硼酸钠 盐酸 (pH =2 90 )缓冲溶液中 ,线性范围为 10～ 10 0 4 μg·L- 1 ,相关系数为 0 9913,检出限为 4 2 μg·L- 1 ,用于合成样品的测定结果令人满意。     

用于激光推进的高功率激光器的选择

 从激光推进的要求出发，阐述了用于激光推进的高功率激光器的选择原则，即激光器必须满足：（1）高的平均功率和峰值功率；（2）高的单脉冲能量；（3）高的重复频率；（4）优良的大气传输特性。主要分析了目前YAG固体激光器、自由电子激光器和TEA脉冲CO₂激光器的特点，通过上述4个方面性能的比较，认为在目前水平下，TEA脉冲CO₂激光器是进行激光推进的首选强激光源，其优点表现在：功率可达10kW量级，单脉冲能量可达0.5~1kJ，重复频率为20~40Hz；激光波长处于大气传输窗口，对大气变化不敏感；工作物质快速流动，不存在热透镜效应和破坏阈值；相关光学元件易于制造；光束质量较好；运行成本低。     

Online Cooperative Learning in Physical Chemistry

The use of cooperative learning in an online setting is examined using the online segment of a recently offered physical chemistry course as an example. The nature and function of classical, face-to-face cooperative learning are outlined. The online course segment is outlined and is analyzed with regard to the criteria for classical cooperative learning. Though this specific course segment functioned poorly when taught as online cooperative learning, it is possible to structure online courses to take advantage of the strengths of cooperative learning. The possible structure and function of an online cooperative learning community are explored, concluding with a specific model for online cooperative learning.     

锤击沉管灌注桩施工时应注意的几个问题

锤击沉管灌注桩应用非常广泛.从桩位的确定、沉管深度、混凝土质量、钢筋笼振入长度、桩身混凝土凿除等几个方面,提出了提高锤击管灌注桩施工质量的一些建议.     

Effects of Substrate Temperature on Helium Content and Microstructure of Nanocrystalline Titanium Films

Helium-charged nanocrystalline titanium films have been deposited by HeAr magnetron co-sputtering. The effects of substrate temperature on the helium content and microstructure of the nanocrystalline titanium films have been studied. The results indicate that helium atoms with a high concentration are evenly incorporated in the deposited titanium films. When the substrate temperature increases from 60℃ to 350℃ while the other deposition＇parameters are fixed, the helium content decreases gradually from 38.6 at.% to 9.2at.%, which proves that nanocrystalline Ti films have a great helium storage capacity. The 20 angle of the Bragg peak of （002） crystal planes of the He-charged Ti film shifts to a lower angle and that of （100） crystal plane is unchanged as compared with that of the pure Ti film, which indicates that the lattice parameter c increases and a keeps at the primitive value. The grain refining and helium damage result in the diffraction peak broadening.     

天光一号预放大器中的放大自发辐射效应

 在三维放大自发辐射（ASE）的模拟计算中，计入了侧壁反射效应以及KrF自发辐射的谱线形状（高斯型、洛伦兹型及平顶型）的影响，并对空间网点的影响进行了考察。经过综合分析，给出了ASE对预放大器放大特性影响的上、下限范围。当计入平顶型频谱分布，壁反射系数为 0 .2时，与不计入ASE的情形对比，天光一号预放大器的提取效率下降为35%。     

清华物理系量子信息研究的新进展

在清华大学物理系成立60周年之际,我们对近年来清华大学物理系量子信息研究的主要进展情况作一介绍,包括量子搜索算法研究,核磁共振量子计算的实验研究,量子通讯的理论与实验研究.在量子搜索算法研究方面,我们提出了量子搜索算法的相位匹配,纠正了当时的一种错误观点,并且提出了一种成功率为100%的量子搜索算法,改进了Grover算法;在核磁共振量子计算实验方面,我们实现了2到7个量子比特的多种量子算法的实验演示;在量子通讯方面,我们提出了分布式传输的量子通讯的思想,应用于量子密钥分配、量子秘密共享、量子直接安全通讯等方面,构造了多个量子通讯的理论方案.在实验室,我们实现了2米距离的空间量子密码通讯的演示实验.     

TDI线扫相机光学通道建模与仿真

卫星相机建模与仿真研究不论在民用还是军事领域都具有重要的理论研究和实际应用价值。根据TDI线扫相机的工作原理建立了一个TDI线扫相机光学通道的数学模型,该模型包括从景物到TDI CCD离散图像的几何投影关系和能量传递关系两部分,对于确定的成像系统,给定景物参数和光学系统参数,就可以确定对应图像传感器上的离散图像。为了验证模型,对一幅卫星图像进行了计算机仿真。建立的模型可以用来研究当成像条件改变时对图像的影响,进一步还可以用来发展虚拟卫星相机系统。     

Detailed Description of Mixed Symmetry States in 94Mo Using Interacting Boson Model

We have investigated the low-lying collective states and electromagnetic transitions in 94Mo within the framework of the interacting boson model. The influence of model parameters on the energy levels and electromagnetic properties has been investigated. The analysis of the obtained results and the parameter values predict that the 23+state is the lowest mixed symmetry state with pure F = Fmax - 1 in this nucleus. The calculated results predicate that the 25+ (two-Q-phonon) mixed symmetry state is closed to the J = 2+ at 2.870 MeV in the experimental data, and the 2.965 MeV state is the lowest mixed symmetry with J = 3+.     

混杂配体金属簇合物的分子振动光谱与结构

由于原子簇化合物在催化，生物活性，功能材料等方面所呈现的重要性，使其成为无机和物理化学最重要的研究领域之一。文章中和谱学方法对一些具有混配体的过渡金属簇合物的结构及其两者之间的关系进行.