液滴低速撞击润湿球面现象观测分析

采用高速摄像仪以10000 帧/s的拍摄速度对液滴低速撞击润湿球体表面过程进行了实验观测, 分析了液滴撞击后的反弹、局部反弹和铺展等现象, 考察了黏度对撞击过程的影响; 在此基础上, 定量讨论了液滴铺展特征参数随撞击速度、球体直径和黏度的变化规律. 观测发现: 黏度较大且撞击速度较低时, 撞击后可能出现反弹和局部反弹, 黏度较小时则不发生; 铺展面积随撞击速度的增大而增大; 黏度增大时, 铺展因子减小; 在球体直径为4–20 mm范围内, 随着球体直径的增加, 铺展因子呈上升趋势. 关键词： 液滴撞击 润湿球面 铺展 黏度     

�߹���΢���մɴ��Ľṹ�Ż�

The structure and its optimization of 2.45GHz high power microwave ceramic window are introduced in this paper. The structure optimization includes optimization of structure dimensions and coolant flowing rate. The microwave properties are sufficient when the thickness of ceramic disk is 4.4mm and the length of cylindrical waveguide is 52.3mm. The maximum thermal stress on the ceramic disk is far less than the limitation that ceramic disk could sustainable stress when the coolant flowing rate is 0.4t×h^-1 . Optimized ceramic window did not appear crack problem after several runs of experiments.     

Correlation between pulse-width and peak luminosity of single-pulse long gamma-ray bursts

With a sample of 21 single-pulse GRBs with redshift measurement and a sample of 65 single-pulse GRBs with pseudo redshift estimated by the luminosity-spectral lag relation, we show that the peak luminosities of GRB pulses are anti-correlated with pulse width, indicating that longer-pulses tend to be dimmer in the gamma-ray band. The anti-correlation is accessible with an internal shock scenario.     

傅里叶变换红外光谱（FTIR）非线性多点定标方法研究

给出了线性定标和非线性多点定标的具体算法,并且应用加拿大BOMEM公司的MR-154傅里叶变换红外光谱仪,液氮制冷型中红外MCT探测器测量了中国科学院上海技术物理研究所研制的HFY-300A型黑体在几种不同温度下的辐射谱,其中的一些辐射谱用于定标,用其中的一个特定温度下的辐射谱来检验定标结果。结果表明这种非线性多点定标方法非常可靠,理论辐射谱与定标后辐射谱相对偏差集中在0.2%附近,最大相对偏差仍小于0.4%。     

The characteristics analysis of a new-style four-mirror axisymmetric-fold-combination cavity adapting to cylindrical discharge region

An axisymmetric-fold-combination (ASFC) cavity composed of two planar mirrors and spherical mirrors was designed. It is a stable-unstable resonator cavity. The light field of radial direction is Gaussian distribution. And in angular orientation, the distribution keeps invariant. It could generate annular CO₂ laser beam with excellent spatial coherence. And the spatial coherence is commendably realized with its stable-unstable cavity structure. The output light intensity distribution of this special model was discussed and simulated. With exterior lenses group, the output beams can be adjusted and controlled better to meet the manufactural requirements. Some references were provided for further research of the cavity with cylindrical discharge region.     

Interplay between out-of-plane magnetic plasmon and lattice resonance for modified resonance lineshape and near-field enhancement in double nanoparticles array

Two-dimensional double nanoparticle （DNP） arrays are demonstrated theoretically, supporting the interaction between out-of-plane magnetic plasmons and in-plane lattice resonances, which can be achieved by tuning the nanoparticle height or the array period due to the height-dependent magnetic resonance and the periodicity-dependent lattice resonance. The interplay between the two plasmon modes can lead to a remarkable change in resonance lineshape and an improvement on magnetic field enhancement. Simultaneous electric field and magnetic field enhancement can be obtained in the gap region between neighboring particles at two resonance frequencies as the interplay occurs, which presents “open” cavities as electromagnetic field hot spots for potential applications on detection and sensing. The results not only offer an attractive way to tune the optical responses of plasmonic nanostructure, but also provide further insight into the plasmon interactions in periodic nanostructure or metamaterials comprising multiple elements.     

InGaAs近红外相机电路设计与实现

随着国外0.9～1.7μm InGaAs近红外相机的迅速发展,目前已被大量应用于工业和军事领域。探讨了InGaAs近红外相机在不同领域的应用,分析了InGaAs材料的优势及探测器选型。结合相应的探测器阵列,从相机偏置电压产生、时序驱动设计与制冷控制等方面给出了InGaAs近红外相机的硬件电路设计方案,解决了研制过程中的部分重难点,并针对后期图像处理进行了仿真验证,达到应用要求。     

Cold atom space clock with counter-propagating atoms

<正>We discuss the feasibility of realizing a cold atom space clock with counter-propagating cold atoms in microgravity.The design of the space clock is based on an atomic beam clock with Ramsey cavity,except that magneto-optical trap(MOT) is placed at each side.Cold atoms are launched simultaneously from the MOTs at both sides of the clock and they move at the counter-direction towards each other.The velocity of the launched atoms is precisely controlled to Ramsauer-Townsend resonance so that no additional collision frequency shift takes place.Such configuration can efficiently cancel the frequency shift resulting from cavity phase shift and increase the signal-to-noise ratio(SNR).     

Subwavelength-resolution direct writing using submicron-diameter fibers

<正>A novel direct writing technique using submicron-diameter fibers is presented.This technique adopts contact mode in the process of writing,and submicron lines with different widths have been obtained. Experimental results demonstrate that the resolution of this technique can be smaller than the exposure wavelength of 442 nm,and 380-nm-wide line is achieved.In addition,the distribution of light fields in the photoresist layer is analyzed by finite-difference time-domain method.     

Optimization of microcrystalline silicon thin film solar cell isolation processing parameters using ultraviolet laser

This study used ultraviolet laser to perform the microcrystalline silicon thin film solar cell isolation scribing process, and applied the Taguchi method and an L₁₈ orthogonal array to plan the experiment. The isolation scribing materials included ZnO:Al, AZO transparent conductive film with a thickness of 200 nm, microcrystalline silicon thin film at 38% crystallinity and of thickness of 500 nm, and the aluminum back contact layer with a thickness of 300 nm. The main objective was to ensure the success of isolation scribing. After laser scribing isolation, using the minimum scribing line width, the flattest trough bottom, and the minimum processing edge surface bumps as the quality characteristics, this study performed main effect analysis and applied the ANOVA (analysis of variance) theory of the Taguchi method to identify the single quality optimal parameter. It then employed the hierarchical structure of the AHP (analytic hierarchy process) theory to establish the positive contrast matrix. After consistency verification, global weight calculation, and priority sequencing, the optimal multi-attribute parameters were obtained. Finally, the experimental results were verified by a Taguchi confirmation experiment and confidence interval calculation. The minimum scribing line width of AZO (200 nm) was 45.6 μm, the minimum scribing line width of the microcrystalline silicon (at 38% crystallinity) was 50.63 μm and the minimum line width of the aluminum thin film (300 nm) was 30.96 μm. The confirmation experiment results were within the 95% confidence interval, verifying that using ultraviolet laser in the isolation scribing process for microcrystalline silicon thin film solar cell has high reproducibility.