Ar+激光辐照下离体猪鼻咽组织的热响应特性

为了获得用于鼻咽癌(NPC)光活检的Ar^ 激光对鼻咽组织的安全光剂量阈值，实验测定了离体猪鼻咽组织在Ar^ 激光辐照下不同位置的温度分布，重点研究了辐照功率密度和波长对组织中温度分布的影响。实验结果表明，组织中的温度分布与探测位置、激光波长以及激光辐照功率密度有关。在同一波长激光辐射下，组织中的温度随着辐照激光功率密度的增大而增大，当辐照功率密度达到1．85W／cm^2时，鼻咽组织黏膜下层的温度可超过41．5℃；在相同功率密度激光的辐照下，波长为514．5nm的激光照射鼻咽组织时的光热效应较488nm波长明显。     

蓝绿光咽后壁组织的光学和荧光特性

对488nm和514．5nm鼻咽癌荧光成像定位系统的灵敏度和成像的对比度进行了实验比较,得到猪离体咽后壁组织光学穿透深度为0．65nm、488nm和0．85mm、514．5nm,二者均大于鼻咽组织黏膜的厚度;当激发光功率为17．0mW／cm^2、光敏剂血卟啉单甲醚(HMME)在生理盐水溶液浓度为5μg／mL时,488nm的荧光产额约为514．5nm的1．3倍;ITT9800C第3代像增强器光阴极面上488nm辐射背景光比514．5nm的响应度低。液体光学模型的系统实验结果表明：当HMME浓度为3μg／mL、光功率密度为22．7mW／cm^2时,488nm激发光源产生的癌模型图像清晰,而514．5nm辐射产生的荧光像可分辨,所以488nm激光更适合做系统的激发光源。     

多脉冲激光辐照皮肤组织的光热效应实验研究

通过实验测定了离体乳猪皮肤组织在多脉冲Nd:YAG激光辐照下径向和轴向不同位置的温度分布,重点研究了激光辐照能量密度、脉冲重复频率以及波长对皮肤组织温升分布的影响.研究结果表明:皮肤组织中的温度分布与探测位置、激光辐照能量密度、脉冲激光的重复频率以及波长密切相关;在激光辐照时间为40 s的情况下,同一波长同一频率时组织温度随能量密度的增加而增大,波长1064 nm、霞复频率10 Hz时的安全光剂量阈值为1118.19 mJ/cm2;同一波长同一能量密度时,组织温度随脉冲激光重复频率的增加面增大;同一能量密度同一频率时,波长为1 064 nm的多脉冲激光辐照皮肤组织时的光热效应较532 nm波长明显.     

强激光辐照下生物组织的瞬态温度场研究

研究生物组织在强激光作用下的瞬态温度分布,探讨强激光作用下生物组织的热传输规律,采用数值方法中的有限差分法求解热传导方程,得出了生物组织纵切面上温度的时空分布图、生物组织轴向温度按指数规律降低及径向上温度按偶次方幂函数规律变化,根据纵切面上温度时空分布图估算出热损伤深度,当激光功率密度分别为175W／cm^2和298W／cm^2时,热损伤深度分别为0．28mm和0．24mm,其值与相关实验值较好地符合。     

掺偶氮苯聚合物的光致折射率改变特性

采用表面反射方法研究块状掺偶氮苯聚合物的光致折射率改变特性及其与光强的依赖关系；实验中，使用514nm的圆偏振Ar^ 激光作为抽运光，632．8nm的He-Ne激光(s偏振)作为探测光。通过改变探测光入射角，测量样品在固定光强(0．570W／cm^2)的前向抽运光激励下表面反射率的改变量．研究样品的折射率改变特性．发现样品的光致折射率改变约为0．0035；研究了这种效应对抽运光强度的依赖关系．发现光致折射率改变随抽运光强度增大而增大．当抽运光强为0．800W／cm^2时，折射率改变量可达10^-2量级。     

基于光纤测温系统的1064 nm光纤激光辐照脂肪组织的温度监控试验研究

激光融脂(laser lipolysis)技术处于较为初步的阶段,目前研究缺少适用人体的参数信息。在激光融脂过程中,温度作为一个重要的量却难以进行实时监控。结合多路光栅光纤测温系统,通过一系列的试验,研究1 064 nm Nd:YAG连续激光在离体猪脂肪样本中的穿透能力、温度分布,以及功率密度、辐照时间等对脂肪温升的影响,设计并验证持续融脂的试验方案。研究结果表明,连续1 064 nm Nd:YAG激光的脂肪透射能力在2 mm以内;其光热效应产生的热量分布也集中在径向、轴向5 mm以内的组织中。另外,温度分布与照射脂肪激光的功率密度、照射时间有着密切的联系;照射温度达到35℃后,一定时间内将温度控制在安全范围内的参数为：功率密度27.08 W/cm~2,照射时间16 s,自然冷却9 s;功率密度40.62 W/cm~2,照射时间9 s,自然冷却9 s。     

连续激光辐照三结GaAs太阳电池热应力场研究

为了研究1070nm光纤连续激光对三结GaAs太阳电池的热力作用, 使用COMSOL软件建立物理模型进行了数值仿真, 得到了不同激光功率密度激光作用下的热应力场。为了验证了热应力计算方法的正确性, 利用栅线投影法测量了功率为16.7W、辐照半径为1mm、辐照时间为10s的激光作用下电池表面的形变, 实验结果与模拟结果基本吻合。结果表明, 辐照半径为1.5cm、功率密度为16.7W/cm2的激光辐照20s时, 底电池中心温度刚好超过电池使用温度; 底电池中心等效应力为96.6MPa, 刚好超过底电池材料的屈服极限; 根据这一结果可推测电池失效与热应力导致的结构损伤有关。该数值模拟结果与实验结果为激光辐照太阳电池的热力效应研究提供了一定的理论依据。     

1070nm连续激光辐照三结GaAs太阳电池的实验研究

为了研究真空环境下波长为1070nm连续激光辐照对三结砷化镓太阳电池输出的影响,采用实验研究的方法测量了不同功率密度激光作用下太阳电池背面温度和负载电压的实时变化。当激光功率密度为8.4W/cm2时,温度升高显著,负载电压下降趋近于零,激光作用结束,电压恢复至初始电压的53%;继续增大激光功率密度至11.7W/cm2,经2.3s后,负载电压降为零且不能恢复,电池已毁伤。结果表明,连续激光作用会引起电池温升,温度升高使负载电压下降; 作用激光功率密度较小时,电池温升幅度较小,负载电压下降幅度也较小,激光停止后,负载电压能逐渐恢复至初始状态; 作用激光功率密度较大时,温升幅度也较大,引起负载电压下降显著,即使激光停止作用,负载电压也不能恢复至初值,此时说明电池已有损伤。该实验结果可以在一定程度上为激光损伤电池机理的研究提供参考依据。     

块状生物组织体准直透射率的直接测量

为了直接测量块状生物组织体的准直透射率，理论分析并实验验证了Ar^＋激光488nm准直光辐照在块状离体猪肌肉组织的透射散射光的空间分布。实验结果表明：组织体厚度大于3～4平均自由程（MFP）时，透射散射光空间分布近似为各向同性，样品后表面的散射光通量为一恒量。满足此条件下，总透射率与准直透射率之差和样品与探测器间距的平方成反比，沿准直光出射的方向改变探测器的位置进行测量，可得到块状生物组织体的准直透射率。     

氩离子激光的微生物学效应研究

本文应用氩离子激光辐照谷氨酸生产菌—钝齿棒状杆菌(Coryneb crenatum),采用不同的波长、不同的功率密度(全谱线波长,功率密度500mW/cm~2;波长4579(?),功效密度2W/cm~2;波长     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.