Thermal characterization of hair using TG-MS combined thermoanalytical technique

Four amino acids and four different hair samples were studied in order to get information about the decomposition of human hair, using combined (TG-MS) and DSC techniques. The thermal stability of the investigated amino acid samples was different. Since they contain identical functional groups (-NH₂, -COOH) some common mass/charge units were identified. However, due to their different chemical composition remarkable differences have also been obtained. The results of the investigation of the amino acids were helpful to study the thermal fragmentation of the hair samples. In our experiments, the effect of the heating rates was also studied. This revised version was published online in July 2006 with corrections to the Cover Date.     

Implementation of an adaptive umbrella sampling method for the calculation of multidimensional potential of mean force of chemical reactions in solution

We describe the implementation of an adaptive umbrella sampling method, making use of the weighted histogram analysis method, for computing multidimensional potential of mean force for chemical reaction in solution. The approach is illustrated by investigating the effect of aqueous solution on the free energy surface for the proton transfer reaction of [H(3)N-H-NH(3)](+) using a combined quantum mechanical and molecular mechanical AM1/TIP3P potential.     

Changes Brought about by a Lens in an Obliquely Incident Laser Beam

In the paraxial optics approximation, we have studied the transformation of a simple Gaussian beam of light obliquely incident on an isotropic lens for the case where the axis of the beam and the principal optical axis of the lens are crossed straight lines. The data obtained are compared with the corresponding results for the case where the axes of the beam and lens are coplanar.     

Submicron External Electro-optic Measuring System Based on an Electro-optic Solid Immersion Lens

In this paper, all electro-optic solid immersion lens (EOSIL) is introduced, which is made of GaAs. A reflecting external electro-optic measuring system based on the EOSIL is built. With a hemispherical GaAs EOSIL used as the external probe, 0.7 µm spot size is obtained when the wavelength of the probing beam from a laser diode is 1.3 µm and a microscope objective with 0.3 numerical aperture is used. The principle of the measuring system is analyzed by Jones matrix. By using the system, the electrical signals propagating on a microstrip transmission line are successfully measured. The voltage sensitivity about 5 mV/ is measured when 10 kHz sinusoidal electric signal is applied on the microstrip line.     

不同因素对可调节人工晶体屈光调节力的影响

首先以Hwey-Lan Liou眼模型为基础，根据等效性原则，保持该眼模型中自然晶状体屈光度不变，对无穷远点成像。然后利用ZEMAX实现光线追迹的方法，将自然晶状体替换为可调节人工晶状体（accommodative intraocular lens，AIOL），结合对人眼成像质量影响的分析，研究了AIOL在眼内的移动度、材料、中心厚度、结构、光学面非球面性等因素对其屈光调节力的影响。结果表明:AIOL移动度对其调节力贡献最大,材料、中心厚度、结构对调节力基本无影响；具有非球面光学面的AIOL调节力相对较大。     

头盔式单目微光夜视仪中光学系统的设计

为提高头盔式单目微光夜视仪中光学系统的成像质量，并满足夜视仪结构紧凑、质量小的指标要求，提出在微光夜视仪光学系统设计中引入高次项非球面透镜的设计方法。针对具体的头盔式微光夜视仪，根据微光物镜、目镜系统技术参数计算理论，确定该微光夜视仪光学系统的技术参数，应用光学设计软件ZEMX上机调试，并在光学系统设计中引入高次非球面透镜，使物镜系统镜片数由原来的9片减少为6片，目镜系统由原来的9片减少为7片，简化了结构，并提高了成像质量。设计结果表明：在头盔式微光夜视系统中采用非球面透镜可以提高系统成像质量，简化系统结构。     

圆锥透镜对偏轴球面波光束的衍射模式

球面波入射圆锥透镜产生的出射光束中心光斑直径较小且焦深长，适合通讯领域长距离测量和准直。针对实际操作中球面波光束入射时很可能与圆锥透镜的中心轴线发生偏移或倾斜，使衍射光场发生变化，着重研究圆锥透镜对偏轴球面波光束的衍射模式，并通过衍射理论和稳相法分析，研究其径向衍射光场的分布特性。使用半径为15mm，底角为1°的圆锥透镜进行计算机仿真和实验，最后将实验结果与理论分析和仿真结果相比较，证明球面波的曲率半径和出射光束的传输距离越小，偏轴对衍射模式的影响越小。该研究结果表明：在激光通讯等长距离通信中，使用曲率半径小的球面波光束代替平面波入射圆锥透镜，不仅可以扩展焦深，还可以降低偏轴对测量的影响。     

电控聚合物分散液晶变焦全息透镜制作

介绍了相位型全息聚合物分散液晶(PDLC)材料全息透镜,在电场作用下液晶微滴折射率逐渐与聚合物折射率匹配,实现透镜电控变焦。研究了微米尺寸和纳米尺寸液晶微滴聚合物分散液晶材料配方特性和微观结构。采用优化纳米尺寸材料配方制作5~6μm聚合物分散液晶盒,采用离轴式平面波和球面波干涉全息写入光路,成功制作电控变焦聚合物分散液晶全息透镜样品。该透镜样品焦距为20 mm,能够正一级衍射放大成像。实现“0”,“1”变焦的驱动电压阈值为60 V。并进一步提出了基于聚合物分散液晶电控变焦元件集成叠加技术实现电控变焦光学成像系统的技术思路。     

F-θ镜头的光学设计

介绍一种适合于激光打标的聚焦镜头－F-θ镜头的光学设计.通过引入桶形畸变，得到的F-θ镜头的像高与入射角成正比，可实现打标速度的线性控制.优化设计得到的工作面积达500×500 mm2的F-θ镜头，结构简单紧凑、聚焦性能达到衍射极限.     

减小球差的环带透镜设计

根据光线经过折射面后像距和折射面参数之间的关系,将折射面划分为若干同心圆环,各圆环之间沿光轴有一定的轴向间隔。一束平行于光轴的光线入射后,经过不同部分光线的像点相互重叠从而使球差减小。根据上述思想用单透镜构造一个透镜称为环带透镜,然后以环数为2的透镜为例用CODE V进行像差分析。和双胶合透镜比较得出:环带透镜的球差、波像差以及轴上点的弥散斑优于胶合透镜,同时光学传递函数指标提高,接近衍射极限。