共查询到20条相似文献,搜索用时 140 毫秒
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《中国光学与应用光学文摘》2006,(3)
TQ171.68 2006032713非球面复制成型技术的研究=Research on the asphericaloptical replication technique[刊,中]/王勤(苏州大学,江苏现代光学技术省重点实验室.江苏,苏州(215006)) ,余景池…∥光学技术.—2006 ,32(1) .—121-123光学非球面复制成型技术是一种通过面形转移的方法成型光学非球面的技术,即将高精度非球面光学元件(母模)的表面利用脱模膜和胶粘剂转移到球面光学元件(基体)的表面上,并保持原非球面光学元件的光学品质,使球面变成非球面。介绍了该技术的基本原理以及所进行的工艺实验(镀膜、脱模、胶合等) ,给出了母模和复制… 相似文献
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针对大角度(大于50°)衍射光学元件低成本、批量化制备的需求,提出一种基于纳米压印技术的制备方法.首先利用光学曝光技术或电子束直写技术制备衍射元件的原始母板,然后将原始母板的结构通过纳米压印过程复制到压印胶上,完成衍射光学元件的制备.由于纳米压印母板可以多次重复使用,降低了制作成本,提高了效率.用该方法制备了不同特征尺寸(最小为250nm,衍射全角为70°)的衍射光学元件,具有良好的衍射效果,实现了对高深宽比浮雕结构的高保真复制.该技术可实现从微米到纳米跨尺度兼容的衍射光学元件的高保真、低成本、批量化制备. 相似文献
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国内外近些年来,对于光学元件表面缺陷的检测技术越来越重视。由于光学元件表面质量的好坏会直接影响到光学系统的性能。文章主要针对曲面光学元件中球面和柱面光学元件表面微缺陷的检测问题,提出了一种基于光偏振特性的检测方法。利用光学元件表面缺陷与无缺陷区域之间透射光偏振态的差异,提高整幅图像中缺陷的对比度。首先基于光的偏振理论,利用偏振片获得偏振照明光,并采用共焦照明的方式获得同时对焦的曲面光学元件缺陷图像。其后,利用计算机对缺陷图像进行处理。结果表明采用光的偏振特性对曲面光学元件表面微缺陷的检测,能够获得高对比度、高分辨率的缺陷特征。此方法很好的提高了曲面光学元件表面微缺陷的检测准确度和检测效率,结果表明缺陷的检测准确率达到了95%。 相似文献
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衍射光学元件的反应离子束蚀刻研究 总被引:3,自引:1,他引:2
本文提出了一种制作衍射光学元件的新方法——-反应离子束蚀刻法.对此技术研究的结果表明:反应离子束蚀刻法具有高蚀刻速率、蚀刻过程各向异性好、蚀刻参数控制灵活等特点,对于衍射光学元件和微光学元件的精细结构制作十分有利.本文详细总结了反应离子束蚀刻过程中各工艺参数对蚀刻速率的影响,并在红外材料上制作了Dammann分束光栅. 相似文献
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全息光学元件是利用全息摄影技术制作的薄膜型光学元件。它利用光的衍射原理,象透镜、棱镜等普通光学元件那样,实现光束韵会聚、发散、偏转、分束、色散、扫描等。全息光学元件是在玻璃或塑料基片上涂附记录介质(如光敏材料、光致抗蚀剂)薄膜,然后在专门设计的曝光系统中曝光,再经显影、干燥、峦封等处理而制备成的。浮雕型全息光学元件还可用热压法大量复制。 相似文献
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用二元光学技术制作计算全息波面变换元件 总被引:9,自引:3,他引:6
基于计算全息原理与二元光学技术设计制作了应用于机载平视显示器(HUD)中的计算全息波面变换元件,该元件具有较高的衍射效率,一块二元相位型计算全息元件的衍射效率比一般计算全息图的衍射效率提高了四倍,并能产生传统光学元件不能实现的光学波面,如非球面,环状面和锥面等,制作工艺简单,复制简便。 相似文献
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Degnan J.H. Kiuttu G.F. Turchi P.J. Graham J.D. Goforth J.H. Lopez E.A. Oona H. Tasker D.G. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1998,26(5):1437-1443
Explosive formed fuses (EFFs) use conducting elements that are deformed by explosive pressure (typically, against dielectric dies). This causes the fuse geometry to change, so that the conducting element cross section decreases. This enables a higher ratio of current conduction to current interrupt time than for normal fuses, and it enables more control of when current interruption occurs. In combination with a suitable output closing switch, EFF's can be used to obtain several hundred kilovolt voltage pulses from inductive stores to drive several ohm loads. With proper choices of inductive store, EFF geometry and material, and output closing switch features, such a voltage pulse can be approximately flat topped for microsecond duration and have a small fraction of microsecond risetime. We present theoretical analysis and circuit simulations which illustrate this, using scaled empirical EFF parameters for inductive stores in the 1 weber flux, several hundred nanohenry range. The circuit simulations were done using MicroCap-IV, with user defined elements. These simulations were done with static inductive stores and with explosive magnetic flux compression generators driving inductive stores 相似文献
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提出了采用两个折射-衍射元件对人眼系统在14°范围内进行色差校正的光学系统设计方法。基于系统光学性能的评价与单片折射-衍射元件色差校正系统的对比验证了本文提出的色差校正系统的性能。结果表明:两种色差校正系统都可以很好地校正人眼的轴向色差。但是,单片折射一衍射色差校正系统引入了横向色差,其由校正前的14.51μm增加到81.4μm,严重影响了边缘视场处的成像质量。而采用双片折射一衍射元件的色差校正系统可同时对轴向色差和横向色差进行校正,使横向色差降为1.64μm。设计的色差校正系统可有效提高视网膜的成像质量,并可用于视觉仪器。 相似文献
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With a diaphragm placed behind the anode foil, dual runaway electron beams have been provided in helium, hydrogen, nitrogen, and air under a pressure of several torrs to several dozen torrs and a high-voltage pulse amplitude of about 250 kV. These beams consist of two pulses with commensurable amplitudes with a time interval between them of several dozen picoseconds to several hundred picoseconds. It has been shown that the breakdown of the interelectrode gap at pressures from several torrs to several dozen torrs may occur in different regimes and dual pulses of the electron beam current are registered when the initial current through the gap is below 1 kA. It has been found that a supershort avalanche electron beam that consists of one pulse is generated when the delay of breakdown equals several hundred picoseconds. It has been shown that, when the gas pressure reaches several hundred Torr, including atmospheric pressure, the runaway electrons are detected behind the foil after the termination of the supershort avalanche electron beam pulse. 相似文献
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A. M. Vorobei O. I. Pokrovskiy K. B. Ustinovich L. I. Krotova O. O. Parenago V. V. Lunin 《Russian Journal of Physical Chemistry B, Focus on Physics》2016,10(7):1072-1077
The capability of arbidol microparticle preparation by supercritical antisolvent (SAS) precipitation was demonstrated. A nonmonotonic dependence of the average particle size on the concentration was found, while the position of the minimum is dependent on the type of solvent used. It is possible to prepare Arbidol particles of various morphology and size from several microns to several hundred microns depending on the conditions. 相似文献
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Summary The anemometric measurements recorded for more than one year on two 232 m high towers supporting the power lines crossing
the Strait of Messina are analysed. The results indicate several meteo-climatic characteristics of considerable interest to
the construction of the bridge over the Strait. It is apparent that: 1) the surrounding orography, although several km from
the points of measurement, located on the north side of the Strait, plays the main role in determining wind distribution,
from ground level up to a height of several hundred metres. In practice the wind blows from four directions 30 degrees each.
2) Two of these (210 and 330 degrees) display velocity distributions of specific interest for the construction of the bridge.
3) The wind blowing up the Strait (210 degrees) is the strongest in all seasons; it has a logarithmic vertical profile, low
turbulence and for the same altitude maintains a constant ratio between vertical velocity (always ascending) and horizontal
velocity. 4) The NW wind is more turbulent, has a nonlogarithmic profile and also has a constant ratio between horizontal
and vertical velocity. 相似文献
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Femtosecond Laser-Induced Breakdown Spectroscopy for Detection of Trace Elements in Sophora Leaves 总被引:1,自引:0,他引:1 下载免费PDF全文
Sophora leaves from several areas in Beijing are analysed by femtosecond laser-induced breakdown spectroscopy (femto-LIBS). Although the used spectral detection system is not time-resolved, the spectral lines of trace mineral elements are detected and analysed. It is proven that the femto-LIBS can be an efficient method to detect mineral trace elements contained in tree leaves which is a biomonitor for atmospheric pollution assessment or botanic studies. An interesting case of correlation between trace elements detected in tree leaves and the pollution of the concerned area is presented, for the first time to our knowledge. 相似文献
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Grigoriev A Sichel R Lee HN Landahl EC Adams B Dufresne EM Evans PG 《Physical review letters》2008,100(2):027604
Nonlinear effects in the coupling of polarization with elastic strain have been predicted to occur in ferroelectric materials subjected to high electric fields. Such predictions are tested here for a PbZr0.2Ti0.8O3 ferroelectric thin film at electric fields in the range of several hundred MV/m and strains reaching up to 2.7%. The piezoelectric strain exceeds predictions based on constant piezoelectric coefficients at electric fields from approximately 200 to 400 MV/m, which is consistent with a nonlinear effect predicted to occur at corresponding piezoelectric distortions. 相似文献
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S. V. Ovchinnikov A. D. Korotaev V. Yu. Moshkov D. P. Borisov 《Russian Physics Journal》2012,54(9):951-964
The special features of the elemental composition, structure-phase and elastically stressed states, and properties of coatings
based on titanium nitride are investigated for different concentrations of Al, Si, Cu, Ni, Cr, and C doping elements using
x-ray fluorescent analysis, x-ray microanalysis, dark-field electronmicroscopic analysis of the crystal lattice bending and
torsion, microhardness measurements, and scratch tests. Influence of the structure and concentration of the doping elements
on the relative fraction of nonmetallic atoms, crystal size, and phase composition of the coating is established. High values
(several hundred degrees per micron) of the lattice bending-torsion with dipole configuration are established for nanocrystals
with sizes smaller than 20 nm. Residual stresses in nanocrystals are estimated for the disclination model of the structural
state. It is demonstrated that the increased degree of coating doping improves the thermal stability of their structure and
properties. 相似文献
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We present a technique to overcome the depth resolution limitation for 3D active imaging. Applying microsecond laser pulses and sensor gate width, a scene of several hundred meters is illuminated and recorded in a single image. The trapezoid-shaped range intensity profile is analyzed to obtain both the reflectivity and the depth of scene. We demonstrate a 3D scene reconstruction in a depth of 650 to 1550 m from only three images with an accuracy of <30 m. This depth accuracy is 10 times better than estimated from the classical resolution limit obtained for depth scanning active imaging with a similar number of images. Therefore, this technique enables superresolution depth mapping with a reduction of image data processing. 相似文献
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分析了静电放电(ESD)辐射场的偶极子模型。用高采样速率数字示波器和定做的宽带电磁与磁场探头测量了计算机操作中人体静电放电产生的瞬态电场与磁场。用FFT分析了静电放电辐射场的频谱。研究了静民放电辐射场对某电路高频信号的影响。研究结果表明,即使是很低电压(2kV)的静电放电,其辐射近场的电场达几百V/m,磁场可达几十A/m静电放电辐射场的频谱极宽,从数兆赫到数千兆赫。静电放电对高频电路的试验结果表明,若不采取有效的防护措施,人体静电放电辐射电磁场会对电路造成一定的影响,如对集成电路与元器件造成“潜在效应”的损害,对电路造成电磁干扰,甚至损坏电子器件。 相似文献