用于高数值孔径物镜的可调光瞳滤波器

根据矢量衍射理论，提出了一种用于提高高数值孔径显微物镜纵向分辨率的可调二元环形光瞳滤波器，通过改变滤波器的环半径获得不同的纵向分辨率，并利用共焦显微术点扩散函数的乘积性大大地降低了旁瓣相对主瓣的比值。模拟结果表明，这种新型滤波器不仅可以提高高数值孔径物镜的纵向分辨率，同时基本上不影响横向分辨率。     

Hg1-xCdxTe/Cd1-zZnzTe的X射线反射率及半峰全宽的动力学研究

X射线衍射摇摆曲线的计算机模拟是一种获得材料晶体质量参量的有效方法，其中材料本征摇摆曲线的计算是计算机模拟的基础。用X射线动力学理论计算了Hg1-xCdxTe和Cd1-zZnzTe本征反射率曲线，并研究了组分、膜厚分别对本征反射率和半峰全宽的影响。结果表明Hg1-xCdxTe和Cd1-zZnzTe的本征反射率和半峰全宽与材料组分和厚度有明显的依赖关系，且该依赖关系取决于X射线在材料中的散射和吸收的相对强弱。薄膜的厚度也是直接影响本征摇摆曲线峰形、半峰全宽和反射率的重要因素，当薄膜厚度小于穿透深度时，表征本征反射率曲线的各个参量均与薄膜厚度有直接的关系。对于(333)衍射面，碲镉汞材料厚度大于7μm后，本征反射率和半峰全宽将不再发生明显变化。     

Investigation of charge effects on poling and stability for corona-poled polymer films

The optimal corona-poling temperature of polymer films was accurately determined by measuring the temperature dependence of the in situ second-harmonic (SH) intensity profile under the applied poling electric field. The in situ SH intensity profile was first measured by probing both the surface voltages and the poling currents induced by surface/space charges for the corona-poled polymer films. Moreover, charge effects on the stability of the chromophore orientation were first studied by using the thermally stimulated discharge-current technique. PACS 72.20.Jv; 42.65.Ky; 73.61.Ph; 81.40.Tv     

Reversible 5′-end biotinylation and affinity purification of synthetic RNA

A reversible biotinylation phosphoramidite was synthesized and incorporated onto the 5′-end of an oligoribonucleotide on a solid phase synthesizer. After cleavage and deprotection, the crude synthetic oligomer mixture was incubated with NeutrAvidin^® coated microspheres, and the failure sequences removed by washing with a buffer followed by treating the microspheres with tetrabutylammonium fluoride to give a high quality unmodified full-length oligoribonucleotide.     

Effect of transverse object position on the reconstructed image of an aperture-limited in-line hologram

It is experimentally demonstrated that the image resolution from an in-line Fraunhofer hologram degrades appreciably when the centre of the diffraction pattern from a 5-bar resolution target is located asymmetrically in the hologram aperture. This effect is confirmed and analysed using calculated and experimentally measured images from holograms of a one-dimensional wire. Increasing asymmetry results in an increasing error in the measured linewidth, and a reduction of image resolution. A simple model based on average fringe contrast is used to predict this decrease in resolution with transverse object position.     

A quantum chaotic clock and damping of the coherent nuclear rotation in the 28 Si +64 Ni dissipative collision

We employ the statistical reactions with memory approach to study oscillating excitation functions in the ²⁸ Si(E _lab = 120–126.75 MeV)+⁶⁴ Ni strongly dissipative reaction and the time evolution of the collision process. The nonself-averaging of the oscillations in the excitation functions is interpreted as indication of quantum chaos and damping of the coherent nuclear rotation in dissipative heavy-ion collisions.     

Barium(II)–2,4‐dinitrophenolate–18‐crown‐6 at 183 K

The title compound, bis(2,4‐dinitrophenolato‐κ²O,O′)(1,4,7,10,13,16‐hexaoxadecane‐κ⁶O)barium(II), [Ba(C₆H₃N₂O₅)₂(C₁₂H₂₄O₆)], is a 1:1 complex of barium(II)–2,4‐di­nitro­phenolate and 1,4,7,10,13,16‐hexaoxa­cyclo­octa­decane (18‐crown‐6). Its structure is located on a crystallographic inversion centre. The temperature dependence of the crystal structure has been studied. The monoclinic β angle of the P2₁/­n space group increases with increasing temperature. The packing structure of the complex is stabilized by intermolecular C—H?O interactions.     

矩形均匀电子束在激光介质中的能量沉积的模拟计算

本文主要论述了0.5MeV,单能垂直入射的电子束在三种不同密度的氟化氪准分子激光介质中的能量沉积。计算是采用Monte Carlo方法的MCSED程序,光轴方向采用周期性边界条件,因此能够给出平行于和垂直于电子束入射方向的沉积能量的空间分布。本文给出了在三种不同密度下的出射电子的角分布。用该程序对垂直入射的,初始能量为1MeV的电子在半无限大Al靶中的沉积能量的计算结果与ONETRAN程序的结果及实验结果的比较表明MCSED程序的计算结果是可靠的。     

Synthesis of 5‐Radioiodoarabinosyl Uridine Analog for Probing the HSV‐1 Thymidine Kinase Gene

Tumor cells transduced with herpes simplex virus thymidine kinase gene have been intensively applied to the field of positron emission tomography via imaging of its substrate. As a pilot synthesis approach, a facile preparation of 5‐[¹²⁵I] iodoarabinosyl uridine starting from commercially available uridine is reported herein.     

原子力显微术轻敲模式中探针样品接触过程及相位衬度研究

借助简单的有阻尼受迫振子模型，研究了原子力显微术轻敲模式中探针与样品接触时间t_c、样品的表面形变D_z和相位衬度对探针设置高度z_c及样品杨氏模量E_s的依赖关系.结果发现,t_c与D_z均随E_s及z_c的增大而减小，同时探针与样品作用过程伴随很小的能量耗散.对轻敲过程中相移量φ的研究表明，E_s较大的样品有较小的φ，且φ随 关键词： 原子力显微术 轻敲模式 相位衬度