1.06μm激光防龋作用研究

研究了Nd:YAG激光抑制牙釉质龋损进展的有效性。48颗牙釉质块经过表面处理后,分为6组:0.01W,0.3W,0.8W,1W,1.4W激光照射组及对照组,每组8块,将对照组及激光处理后的牙釉质块分别投入到5mL乳酸液(0.1mol/L)中,置于37℃水浴中恒温72h。用显微硬度计及扫描电子显微镜对其硬度及表面形态进行研究,结果显示与对照组相比,0.3W激光照射组龋损程度最小(p0.01),防龋作用显著。同时对激光防龋机理进行了探讨。提出恰当控制激光参数,使牙釉质表面瞬时温升为300℃～400℃时,可以达到最佳防龋效果。     

Er:YAG激光照射对牙釉质与玻璃离子粘接的影响

目的:采用剪切力测试,比较Er:YAG激光照射对牙釉质与玻璃离子之间剪切粘接强度的影响.方法:选取105颗年轻前磨牙、第三磨牙,用涡轮手机按近远中方向将离体牙切割成颊/舌两部分.将受试牙随机分成7组,1组:裂钻预备,2组:裂钻+37%磷酸,3组:裂钻+玻璃离子液,4组:Er:YAG激光预备,5组:Er:YAG激光+37%磷酸,6组:37%磷酸+玻璃离子液,7组:Er:YAG激光+二次激光.玻璃离子充填,将粘接试件置于37°蒸馏水中储存24小时后进行剪切力测试,计算粘接试件牙的抗剪切粘接强度.扫描电子显微镜观察牙釉质经不同处理后的表面形态变化。结果:37%磷酸和玻璃离子液预处理均有助于即刻剪切粘接强度的提高,差异有统计学意义(p0.05)。激光预备较裂钻预备的即刻剪切粘接强度大,差异有统计学意义(p0.05)。而在激光预备面的基础上使用37%磷酸预处理和二次激光的应用与单纯的激光预备相比,其即刻剪切粘接强度并未提高,差异无统计学意义(p0.05)。结论:Er:YAG激光预备、37%磷酸和玻璃离子液都可以提高牙釉质和玻璃离子之间的剪切粘接强度.37%磷酸、玻璃离子液预处理及二次激光不能使Er:YAG激光预备后的剪切粘接强度提高。     

低功率磁作用半导体激光照射对神经功能恢复的影响

目的 :探讨低功率磁作用半导体激光对家兔神经功能恢复的影响。方法 :用 5 6只体重 2 .5kg左右的家兔随机分为 3 ,6,9和 12周 4个观察期组 ,每个观察期组随机分为半导体激光照组 (各用家兔 5只 )、磁作用半导体激光照组 (各用家兔 5只 )和对照组 (各用家兔 4只 )。麻醉后 ,均切断左侧腓总神经 ,用 9 0尼龙单丝对端吻合神经外膜。各照射组在术后 1d开始照射家兔L5 ,6脊髓节段 ,照射激光输出功率为 2mW ,磁作用半导体激光照射采用在激光输出端安置强度为 5mT的恒磁场作用在激光上 ,每天照射 5min ,连续照射 7d。对照组不照射 ,均按期观察。结果 :术后 3周 ,各照射组看到细小而稀少的再生轴突 ,对照组直到术后 9周才看到 (P <0 .0 1) ,磁作用激光照射组优于激光照射组 (P <0 .0 5 ) ;各照射组的腓总神经潜伏速率和动作电位波幅均优于对照组 (P <0 .0 1) ,磁作用激光照射组优于激光照射组 (P <0 .0 5 )。展趾功能到术后 12周 ,磁作用激光照射组与侧健相同 ,激光照射组恢复到磁作用照射组 9周水平 ,对照组才恢复到磁作用半导体照射组近 6周的水平。结论 :低功率的磁半导体激光促进了脊髓运动神经细胞功能 ,加速了轴突再生。     

光动力疗法对人工龋口腔生物膜菌斑的影响

为探讨光动力疗法(PDT)对人工龋菌斑生物膜的的作用,选用变形链球菌在体外构建符合人体生理环境的人工龋模型,选择血卟啉单甲醚(HMME)为光敏剂,激光照射选用半导体激光器,波长为635 nm,输出功率为10 mW,能量密度为12.47 J/cm2.用50个釉质块形成人工龋模型,随机分成5组,每组10块,分别为:1)HMME组;2)激光照射组;3)PDT防龋组;4)0.05%(质量分数)洗必泰处理组为阳性对照;5)0.9%(质晕分数)生理盐水处理组为阴性对照.依照平板细菌计数法观察不同处理方法对人工龋菌斑生物膜变形链球菌活力的影响.结果表明,与阴性对照组相比,HMME组人工龋口腔生物膜中变形链球菌数量(CFU/mL)无显著性差异(P＞0.05),杀菌率仅为0.05%;激光照射和0.05%洗必泰均能使人工龋口腔生物膜中变形链球菌数量显著减少(P＜0.05),杀菌率分别为59.94%和58.52%;而PDT防龋处理可使人工龋口腔生物膜中变形链球菌数量更为显著减少(P＜0.05),杀菌率高达99.36%.HMME-PDT可有效杀灭人工龋口腔生物膜中的变形链球菌,为预防龋病提供了一种有效的新途径.     

低功率半导体激光照射对神经功能恢复的影响

目的探讨低功率半导体激光对家兔神经功能恢复的影响。方法用 36只体重 2 .5kg左右的家兔随机分为 3,6 ,9和 12周 4个观察期组 ,每个观察期组随机分为半导体激光照射组 (各用家兔 5只 )和对照组 (各用家兔 4只 )。麻醉后 ,均切断左侧腓总神经 ,用 9/0尼龙单丝对端吻合神经外膜。各照射组在术后 1d开始照射家兔L5 ,6脊髓节段 ,照射激光输出功率为2mW ,每天照射 5min ,连续照射 7d。对照组不照射 ,均按期观察。结果术后 3周 ,可在照射组看到细小而稀少的再生轴突 ,对照组直到术后 6周才看到 (P <0 .0 1)。照射组的腓总神经潜伏速率均优于对照组 (P <0 .0 1) ,动作电位波幅照射组也优于对照组。展趾功能到术后 12周 ,照射组与侧健相同 ,对照组才恢复到照射组 6周的水平。结论低功率的半导体激光促进脊髓运动神经细胞功能 ,加速轴突再生     

XeCl准分子激光对聚对苯二甲酸乙二酯的表面接枝改性

用XeCl准分子激光照射聚对苯二甲酸乙二酯 (PET)薄膜 ,并同时进行表面接枝 ,提高薄膜表面亲水性。研究了激光能量和脉冲次数对照射和接枝后PET薄膜表面亲水性的影响 ,对比了激光照射烧蚀和接枝薄膜的表面性质差异 ,并分析了激光照射和接枝后样品重量变化的影响因素 ,提出了一种新的接枝率计算公式     

He-Ne激光照射对大鼠神经损伤后自残及神经再生的影响

本实验利用大鼠坐骨神经钳夹损伤模型 ,观察了氦氖 (He -Ne)激光照射 (A组 )、直流电针刺激器 (B组 )、对照组为 (C组 )对神经损伤后自残及神经再生的影响。结果 :( 1)术后 2 0d ,A组的右后足趾自残率为 13 % ,而B、C组分别为 46%、80 % ,A组的自残率显著低于其它各组(P <0 .0 0 1) ;( 2 )右侧屈肌反向阈 :当激光照射时光斑直径 0 .6cm ,功率密度为 3 5 .3 9mW/cm2 时 ,可引出短潜伏期 ( 4 5 -15 0ms)及长潜伏期 ( 12 5 5 2 5ms)传入纤维反应 ;( 3 )术后 2 0d脊神经节的标记细胞百分率分别为 11.1% (A组 )、5 .2 % (B组 )及 1.1% (C组 ) ;脊髓前角的标记细胞百分率分别为 16.6% (A组 )、8.1% (B组 )及 1.9% (C组 )。上述结果表明 :氦氖 (He -Ne)激光照射在抑制神经损伤后自残及促进周围神经再生等方面具有更显著的生理功效     

He-Ne激光照射促进大面积皮肤创面愈合的临床观察

目的 :　探讨低强度He -Ne激光照射辅助治疗对大面积皮肤创面愈合的疗效。方法 :选择骨外伤患者 2 10例 ,分为常规治疗组 ( 10 7例 )和低强度He -Ne激光辅助治疗组 ( 10 3例 ) ,各自分为二个亚组即不规则及长切口组 ( 1亚组 )和大面积皮肤损伤组 ( 2亚组 ) ,回顾分析低强度He -Ne激光照射的疗效。结果 :常规治疗组和低强度He -Ne激光照射辅助治疗组中的 1亚组皮肤创面平均愈合时间分别为 10 .8± 1.3天和 7.1± 1.1天 ,P <0 .0 5。而 2亚组创面平均愈合时间分别为 13 .4± 1.7天和 8.9± 1.5天 ,P <0 .0 5。两大组创面均达到临床治愈 ,但优良愈合率在常规治疗组和低强度He -Ne激光照射辅助治疗组中的 1亚组分别为 75 %和 90 % ,P <0 .0 5。在 2亚组分别为 5 4%和 87% ,P <0 .0 5。结论 :低强度He -Ne激光照射可显著缩短大面积皮肤创面愈合时间 ,同时 ,可明显提高皮肤创面愈合质量 ,减少瘢痕疙瘩形成和愈合皮肤不适感     

Er:YAG激光和Er,Cr:YSGG激光消融牙釉质的阈值研究

通过离体牙实验,采用Er:YAG激光和Er,Cr:YSGG激光对人恒牙牙釉质进行消融阈值的实验研究.使用渐增的2～10 J/cm2能量密度对70个牙釉质样本进行辐照,应用体视显微镜和扫描电镜观察辐照后牙釉质表面的形态改变.结果表明,Er:YAG激光和Er,Cr:YSGG激光均能有效地消融牙釉质,Er:YAG激光消融牙釉质的阈值为3.19～4.36 J/cm2,Er,Cr:YSGG激光消融牙釉质的阚值为4.12～4.80 J/cm2.     

激光防龋研究及第一代样机通过鉴定

1977年在北京市科委组织领导下,成立了由北医口腔医院、北京市口腔医院、首都医院口腔科及电子部11所组成的激光防龋协作组,开始Nd~(3 ) :YAG脉冲激光防龋研究。经近二年多反复实验,证明激光防龋有效,并摸索出合适的激光参数。1980年于11所及北京工业学院四系协作,制成有观察瞄准装置的防龋样机。利用该机所进行的实验,证明激光辐射有抗酸作用,不改变牙釉硬度,对活体动物牙髓无损伤。1984年,对20名儿童进行了临床防龋激光辐照,受照者主诉无不适感觉,切片证实对牙髓无影响。1984年11月15日,北京医学院受北京市科委委托,组织了对上述成果的鉴定会。由七名教授、付教授、高级工程师组成     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.