查询词典 laser light

For the laser coordinate measuring machine, the single CCD and the structure light are used to match the 3D object surface data. A new ladder-shaped calibration block is designed and two images are taken: one is structured stripe image and the other is laser plane image by this block. The laser plane and camera calibration can be accomplished by both images.

由于关节式坐标测量机的激光测量头，使用单摄像机和线结构光来匹配被测物体表面的三维数据，本文设计了一种新型的阶梯形标定块，通过标定块图像和激光条纹图像完成了摄像机的内外参数标定和激光平面参数标定。

The vapour and plasma ignition times of the target are got based on the equation of heat conduction and cascade model. We suppose that the plasma is ignited when 210 generations of new electrons are born in vapour generation time. The influence of temperature on the thermodynamics and optics parameters of material also have been considered in the model. The resulting theory has good agreement with the experiment and overseas report. A blade method to measure the laser spot is given in this paper with validation and error analysis. The plasma threshold of metals in atmosphere and water ambients both are diagnosed with the light deflection and piezoelectric transducer. A Q-switched pulsed Nd:YAG laser operating at infrared (1064nm), visible(532nm) and ultraviolet (355nm) wavelengths has been used. Al、Fe、Cu are used as targets and get a similar results with both method. Theoretical and experimental analyses are applied on the influence of wavelength on the threshold have been done, both of which have shown that the plasma threshold of metals decrease as the laser wavelength increases; The plasma threshold of metals are higher in water than in air and the pressure of the shock wave in water is five times higher than in air.

从热传导方程和雪崩电离机制出发，假设当电子增值2~(10)倍时，考虑了温度对材料热力学和光学参数的影响时，得到了气化和等离子体点燃的时间，利用该模型进行计算得到的结果与国内外报道及自行通过实验测得的阈值基本一致；提出了利用刀刃法测量激光光斑面积的方法，并通过实验进行了验证和误差分析；利用光偏转装置和压电换能器分别对空气和水中金属等离子体点燃阈值进行了实验诊断，激光器均为调Q—YAG激光器(波长1064nm，532nm，355nm，脉宽10ns)，靶材分别为Al、Fe和Cu，两种测试方法得到的等离子体点燃阈值基本一致；本文从实验和理论计算两个方面讨论了波长对等离子体点燃阈值的影响，均得到了等离子体点燃阈值随着波长的增加而减小的结论；对空气中和水中不同环境下金属等离子体的点燃阈值进行了比较研究，得到了金属在水中的等离子体点燃阈值比空气中的大，且水中产生的冲击波的压强是空气中的5倍左右的结论。

A numerical model was established by combining the seven-flux model of light propagation with the two-dimensional hyperbolic heat conduction model in cylindrical coordinates. It showed that there exists a great discrepancy between the results obtained by treating the laser irradiation as volumetric absorption (i.e. taking laser scattering and absorption into consideration) and those obtained by treating the laser irradiation as the second boundary condition.

将激光传输的七流模型与圆柱坐标系内的二维双曲型导热模型相结合建立了理论模型；将激光照射处理为容积吸收(即考虑激光在生物组织中的散射和吸收)所得到的计算结果，与将激光照射处理为第二类传热边界条件所得到的计算结果相比，两者差别很大；考察了激光照射下散射系数和吸收系数对生物组织内双曲型导热的影响。

An oxygen-bubble and white-light speckle velocimetry method is presented.Instead ofpulsed laser and commonly used particle,a sheet like-bubble mass generated from anade wire byeletrolysing water is used as particle tracer,a white light flash set controlled by digital time delaycircuit is used as double pulsed light source,and 2-D velocity distribution in a sectional planewithin flow field can be obtained without using light sheet technique.

提出了一种氧气泡粒子白光散斑测速技术，与以往散斑测速方法不同的是，采用电解水时电解阳极丝上产生的氧气泡做为流场示踪粒子，用两个闪光时间间隔由数字延时电路控制的普通闪光灯做为散斑底片拍摄时的双脉冲光源，并且勿需片光技术，即可获得流场内部一个截面上的二维速度分布。

The study results indicate that as emission power increases, the peak power density on the section of a certain distance will increase firstly, then it will descend and that the peak light intensity on the section will increase with the increasing of spot radius of basic mode Gaussian beam. As the propagation distance increases, the peak light intensity on the section will descend gradually, and the laser energy will spread. The light intensity distribution exhibits straw hat shape on a certain conditions, in other word to say, the central light intensity is less than acroteric light intensity.

结果表明，无风稳态热晕效应存在时，随发射功率的增大，一定传输距离截面上的峰值功率密度先增人后减小；截面上的峰值光强随基模高斯光束的腰斑半径的增大而增大；随着传输距离的增大，截面上峰值光强在逐渐减小，能量在逐渐向周围扩展；在一定条件下，截面上的光强分布会呈现中心光强小于周围光强的&草帽型&分布。

When laser diode illuminates the rough surface moving transversally across the light beam, the feedback light forms the random speckle due to the random pattern of the target surface, causing random fluctuations in the laser output, which is called as self-mixing speckle interference.

让半导体激光器的光学反馈来自垂直地照射的粗糙表面，把光强调制成为随机的散斑信号。

We gained 3.3W green laser when we pumped the system at 25W power while the temperature of Nd: YVO4 was controlled at 22℃, LBO was at 18℃, the efficiency of light-light reached 14.3%, and the conclusion nearly come to the same thing with the theory, this result is better than the need to gain 3W green laser of industrialization, and surpasses it 10 percentage.

使Nd∶YVO_4晶体的温度控制在22℃、LBO的温度控制在18℃，整个系统在泵浦光功率为25W的情况下，获得了3.3W的绿光输出，光-光转换效率为14.3％，实验结果与理论预期基本相符，比产业化项目的目标要求—绿光输出3W高出10个百分点。

To suppress the noise which caused by the fuzzy character of XLPE sample, the size of the photodetector was determined based on the analysis of the light intensity distribution in the spatial frequency plane when the laser beam passing through the sample was collected by lens. A series of detectors were designed to eliminate the time response decreasing effect caused by the increasing of the detector size. The developed laser system could resolve defects of 40 um diameter in XLPE tape with the 120um diameter and 400Hz scanning laser beam. after above results was used.

为了消除由于XLPE材料光弥散效应引起的信号噪声对信号幅度测量的影响和提高测试速度，研制了阵列组合式光电探测器，理论分析和实验验证都证明了该探测器有较好的频响特性和较低的噪声水平，应用这两项成果组成的信号系统及微机数据采集电路可在400Hz扫描频率下，扫描宽度所限制的120μm光束直径下获得40μm的测量分辨率。

The plasma ignition threshold of metal is got through experimental and numerical study. The vapour and plasma ignition times of the target are got based on the equation of heat conduction and cascade model. We suppose that the plasma is ignited when generations of new electrons are born in vapour generation time. The influence of temperature on the thermodynamics and optics parameters of material also have been considered in the model. The resulting theory has good agreement with the experiment and overseas report. A blade method to measure the laser spot is given in this paper with validation and error analysis. The plasma threshold of metals in atmosphere and water ambients both are diagnosed with the light deflection and piezoelectric transducer. A Q-switched pulsed Nd:YAG laser operating at infrared (1064nm), visible(532nm) and ultraviolet (355nm) wavelengths has been used. Al、Fe、Cu are used as targets and get a similar results with both method. Theoretical and experimental analyses are applied on the influence of wavelength on the threshold have been done, both of which have shown that the plasma threshold of metals decrease as the laser wavelength increases; The plasma threshold of metals are higher in water than in air and the pressure of the shock wave in water is five times higher than in air .

从热传导方程和雪崩电离机制出发，假设当电子增值210倍时，考虑了温度对材料热力学和光学参数的影响时，得到了气化和等离子体点燃的时间，利用该模型进行计算得到的结果与国内外报道及自行通过实验测得的阈值基本一致；提出了利用刀刃法测量激光光斑面积的方法，并通过实验进行了验证和误差分析；利用光偏转装置和压电换能器分别对空气和水中金属等离子体点燃阈值进行了实验诊断，激光器均为调Q－YAG激光器（波长1064nm，532nm，355nm，脉宽10ns），靶材分别为Al、Fe和Cu，两种测试方法得到的等离子体点燃阈值基本一致；本文从实验和理论计算两个方面讨论了波长对等离子体点燃阈值的影响，均得到了等离子体点燃阈值随著波长的增加而减小的结论；对空气中和水中不同环境下金属等离子体的点燃阈值进行了比较研究，得到了金属在水中的等离子体点燃阈值比空气中的大，且水中产生的冲击波的压强是空气中的5倍左右的结论。

Exhibition hall is divided into four, nine galleries, one of electric and magnetic layer for the area, power and machinery area, math section, the universe and Space Pavilion, set up a high-voltage discharge, electric magnetic Gallery, bowls, a typical mechanical transmission, three-dimensional coordinates and other exhibits; the second floor for the sound and light booth, Applied Technology Pavilion, set up a light display, three-dimensional holographic images, sound simulation, laser laser, simulated driving and other exhibits; three for the Life and Health Pavilion, set up a false impression cylinder, fitness tests, brain and facial features, body systems, such as exhibits; underground floor for temporary exhibitions; in the Office of the Hebei Academy of Sciences set up a pavilion style.

展厅共分四层，九个展区，其中一层为电与磁展区、力与机械展区、数学展区、宇宙与航天展区，设置了高压放电、磁电廊、滚球、典型机械传动、三维坐标等展品；二层为声与光展区、应用技术展区，设置了光路展示、全息立体影像、声音模拟、激光内雕、模拟驾驶等展品；三层为生命与健康展区，设置了错觉滚筒、体能测试、大脑与五官、身体各系统等展品；地下一层为临时展览；中厅设置了河北院士风采展区。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。