共查询到20条相似文献,搜索用时 93 毫秒
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采用非同时读出条件下晶体两波耦合实验装置,在相同的入射光参量下,研究了激光波长(λ)对Ce:KNSBN晶体两波耦合增益系数(r)、衍射效率(n)、响应时间及光扇效应入射光强度阈值的影响.结果显示,激光波长不同时,r、n,响应时间随光入射角2θ的演化趋势相同,但不同波长光入射时,对应相同的2θ,r、n及响应时间不同;激光波长不同时,Ce:KNSBN晶体中光扇效应的入射光强度阈值不同,λ为532nm时,阈值为38mW/cm2,λ为632.8nm时,阈值为26mW/cm2. 相似文献
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低强度激光对软骨胶原合成和细胞增殖影响 总被引:1,自引:0,他引:1
研究了810 nm低强度Ga-Al-As半导体激光对兔软骨细胞增殖和胶原合成的影响.取新西兰白兔的关节软骨细胞,用浓度为2%的新生牛血清(NCS)培养媒介培养.激光功率密度分别为1.75、3.50、5.25、7.00和8.75 mW/cm2,以连续方式每天照射软骨细胞5 min,共5 d.分别用四甲基氮唑盐(MTT)法和氯胺T消化法检测细胞的增殖和胶原蛋白合成.结果发现:第8天实验结束时,各激光照射组细胞数量随激光强度线性增加,与无激光照射组的差异有统计学意义(P<0.01),其中最佳照射功率密度为7.00 mW/cm2;第8天实验结束时,激光照射组胶原含量显著低于对照组(P<0.01),8.75 mW/cm2组与3.50~7.00 mW/cm2组有显著差异(P<0.05).激光照射7.00 mW/cm2组与对照组第2、4、6和8天胶原含量的测定表明,照射组胶原含量先增加后降低,其中第6天照射组胶原含量最高,与相应对照组有极显著差异(P<0.01),对照组胶原含量在第6天后急剧增加,第8天与照射组有极显著差异(P<0.01).研究结果表明,低强度Ga-Al-As半导体激光能促进兔关节软骨细胞的生长,有望成为临床治疗软骨损伤的一种有效方法. 相似文献
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建立了光动力疗法(PDT)照射方式下578nm激光视网膜热损伤能量密度阈值计算的数值模型。模型由模拟激光能量在组织内分布规律的基于网格的Monte Carlo模拟方法、计算组织内温度分布的考虑组织热物性参数以及血液灌注率动态变化的Penens生物传热方程和计算组织热损伤程度的Arrhenius方程3部分组成。数值结果表明,视网膜热损伤能量密度阈值随黑色素含量、观测时间和光斑大小不同而不同:黑色素含量越高,热损伤能量密度阈值越小;观测时间越长,热损伤能量密度阈值越大;光斑直径越大,热损伤能量密度阈值越小。活体动物实验验证了数值结果的精确性。 相似文献
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Michael Reilly 《半导体技术》2004,29(12)
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. 相似文献
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Thomas M.Trexler 《半导体技术》2004,29(5)
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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Qi-jiang Ran Pei-de Han Yu-jun Quan Li-peng Gao Fan-ping Zeng Chun-hua Zhao 《光电子快报》2008,4(4):239-242
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. 相似文献
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It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory. 相似文献
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Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers
A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it. 相似文献
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A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working. 相似文献
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《中国通信》2014,(7)
正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks 相似文献