共查询到20条相似文献,搜索用时 125 毫秒
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以硬脂酸锌和过氧化氢为原料,采用油相法一步合成出一种特殊的氧化锌花状纳米结构。利用透射电镜、高分辨电镜、X射线衍射等对其形貌和结构的分析表明:花状氧化锌纳米颗粒结构为六方晶相,大小约为30nm。吸收光谱和荧光光谱测量显示该纳米结构有显著的近带边紫光发射特性,对应的缺陷发光强度较弱,表明这一纳米结构有较好的光学特性,因此在生物荧光标记方面有着潜在的应用价值。 相似文献
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为了满足纳米级表面形貌样板的高精度非接触测量需求,研制了一种高分辨力光学显微测头。以激光全息单元为光源和信号拾取器件,利用差动光斑尺寸变化探测原理,建立了微位移测量系统,结合光学显微成像系统,形成了高分辨力光学显微测头。将该测头应用于纳米三维测量机,对台阶高度样板和一维线间隔样板进行了测量实验。结果表明:该光学显微测头结合纳米三维测量机可实现纳米级表面形貌样板的可溯源测量,具有扫描速度快、测量分辨力高、结构紧凑和非接触测量等优点,对解决纳米级表面形貌测量难题具有重要实用价值。 相似文献
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星载高分辨力、大视场高光谱成像仪光学设计 总被引:1,自引:1,他引:0
根据高分辨力,大视场的要求,考虑到市售探测器的限制,提出了视场分离分光的方法,分析了视场分离分光的原理.利用此方法设计了一个星载高分辨力、大视场高光谱成像仪光学系统,该系统由11.42°远心离轴三反消像散(TMA)望远系统和2个Offner凸面光栅光谱成像系统组成,运用光学设计软件CODE V对高光谱成像仪光学系统进行... 相似文献
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镀膜玻璃光学与色度学特性的计算研究 总被引:1,自引:1,他引:0
本文对如何计算镀膜玻璃的光学与色度学特性这一问题做了详细系统的分析和研究。建立了考虑镀膜玻璃吸收这一因素的数学模型,给出了膜面和玻面透射率和反射率的理论计算公式,并做了实验验证。最后,应用此模型对镀有MOⅡ/M(N)/MOⅠ/G型膜系的光学和色度学特性做了理论研究。 相似文献
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为了根据经典的弹簧模型进行螺栓联接的最优计算,还需要精确地知道载荷系数n。作者在数值和实验的研究中,借助于光学的变形分析,查明了主要参数对螺栓联接的传力特性的影响,并用一个模型说明之。该模型以观察联接的夹紧区域为依据。因而在螺栓联接的计算中具有极重要的价值。 相似文献
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W.J. Firth 《Journal of Modern Optics》2013,60(5):967-968
Abstract Coherence tomo- and topography have great potential in the building of optical measuring tools for a lot of different technical and biological applications. One major limiting property of scanning coherence methods is their data acquisition time. In this paper we describe two methods for increasing the measuring speed; one for an analogue and one for a digital preprocessing sensor. In particular, we present a novel scanning device for an analogue 1-D sensor which enables measurements with a very fast vertical scanning rate to be made. A periodical change of the optical path difference of up to 3 mm and frequencies of 1200 Hz and more can be achieved by using a resonant scanner. We describe an optical fibre setup using this novel scanner in combination with a homemade low cost light source which is most appropriate for optical fibre coherence application. 相似文献
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A thin film of electron-trapping material (ETM), when combined with suitable optical bistability, is considered as a medium for optical implementation of bioinspired neural nets. The optical mechanism of ETM under blue light and near-infrared exposure has the inherent ability at the material level to mimic the crucial components of the stylized Hodgkin-Huxley model of biological neurons. Combining this unique property with the high-resolution capability of ETM, a dense network of bioinspired neurons can be realized in a thin film of this infrared stimulable storage phosphor. When combined with suitable optical bistability and optical interconnectivity, it has the potential of producing an artificial nonlinear excitable medium analog to cortical tissue. 相似文献
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Alireza Arandian Zeinab Bagheri Hamide Ehtesabi Shima Najafi Nobar Neda Aminoroaya Ashkan Samimi Hamid Latifi 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(28)
Miniaturized laboratories on chip platforms play an important role in handling life sciences studies. The platforms may contain static or dynamic biological cells. Examples are a fixed medium of an organ‐on‐a‐chip and individual cells moving in a microfluidic channel, respectively. Due to feasibility of control or investigation and ethical implications of live targets, both static and dynamic cell‐on‐chip platforms promise various applications in biology. To extract necessary information from the experiments, the demand for direct monitoring is rapidly increasing. Among different microscopy methods, optical imaging is a straightforward choice. Considering light interaction with biological agents, imaging signals may be generated as a result of scattering or emission effects from a sample. Thus, optical imaging techniques could be categorized into scattering‐based and emission‐based techniques. In this review, various optical imaging approaches used in monitoring static and dynamic platforms are introduced along with their optical systems, advantages, challenges, and applications. This review may help biologists to find a suitable imaging technique for different cell‐on‐chip studies and might also be useful for the people who are going to develop optical imaging systems in life sciences studies. 相似文献
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S. Henkel D. Holländer M. Wünsche H. Theilig P. Hübner H. Biermann S. Mehringer 《Engineering Fracture Mechanics》2010,77(11):2077-2090
The observation of cracks with curved crack path has to be done optically. It is shown that a modified commercial flat bed scanner and a combination of a high-resolution scanner camera system with 10,000 × 10,000 pixels with a telecentric lens are appropriate for high-resolution (up to 8 μm/pixel) optical recording of multiple crack ends on sample areas up to 210 mm × 290 mm. The high-resolution photographs are suitable for determination of crack lengths. It is also possible to observe crack paths or geometrical crack tip parameters and strain fields by image correlation. The method is used to determine static crack resistance and cyclic crack growth curves on center crack tension and biaxial cruciform samples.Furthermore, the paper presents an improved finite element technique for the simulation of curved fatigue crack growth in a multiple arbitrarily pre-cracked isotropic sheet under biaxial plane stress loading applying a predictor-corrector procedure in combination with the modified virtual crack closure integral (MVCCI) method including the consideration of the plastic limit loads. For this, the program PCCS-2D was extended to analyse the crack growth and the plastic limit load for each crack propagation step in a fully automatic simulation. The proposed solution algorithm provides a powerful tool for flaw assessment with the failure assessment diagram procedure in combination with a numerical crack path simulation. Finally, the simulation is verified experimentally. 相似文献
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Near-field optical imaging of flagellar filaments of salmonella in water with optical feedback control 总被引:2,自引:0,他引:2
We report on the high-resolution observation of biological samples in water with a collection-mode near-field optical microscope (c-mode NOM) operating under optical feedback control. With rapidly decreasing evanescent field power used as the feedback signal, for the first time to our knowledge, an image of straight-type flagellar filaments of salmonella in water has been obtained. The estimated diameter of a single filament is around 55 nm with a pixel size of 10 nm. A comparison with its nominal value of 25 nm obtained from electron microscope observations under high vacuum confirms that our c-mode NOM performs high-resolution imaging in water. 相似文献
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Experimental demonstration of a no-moving-parts free-space wavelength-multiplexed optical scanner (W-MOS) is presented. With fast tunable lasers or optical filters and planar wavelength dispersive elements such as diffraction gratings, this microsecond-speed scanner enables large several-centimeter apertures for subdegree angular scans. The proposed W-MOS design incorporates a unique optical amplifier and variable optical attenuator combination that enables the calibration and modulation of the scanner response, leading to any desired scanned laser beam power shaping. The experimental setup uses a tunable laser centered at 1560 nm and a 600-grooves/mm blazed reflection grating to accomplish an angular scan of 12.92 degrees as the source is tuned over an 80-nm bandwidth. The values for calculated maximum optical beam divergance, required wavelength resolution, beam-pointing accuracy, and measured scanner insertion loss are 1.076 mrad, 0.172 nm, 0.06 mrad, and 4.88 dB, respectively. 相似文献
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A Neuromorphic Chip That Imitates the ON Brisk Transient Ganglion Cell Set in the Retinas of Rabbits
Li-Ju Lin Chung-Yu Wu Roska B. Werblin F. Balya D. Roska T. 《IEEE sensors journal》2007,7(9):1248-1261
In this paper, a new CMOS design methodology is proposed to implement CMOS neuromorphic chips which imitate the ON brisk transient ganglion cell (GC) set of rabbits' retinas. The measurement results on the fabricated CMOS neuromorphic chip are consistent with the biological measurement results. Thus, the biological functions of the chip have been successfully verified. It can be used to understand more biological behaviors and visual language of retinas under different input optical images which have not yet been tested in biological experiments. Based on the results, the full GC sets of retina can be designed. Thus, many potential applications of retinal chips on motion sensors, computer vision, retinal prosthesis, and biomedical devices are feasible. 相似文献
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Longitudinal spatial coherence (LSC) is determined by the spatial frequency content of an optical beam. The use of lenses with a high numerical aperture (NA) in full-field optical coherence tomography and a narrowband light source makes the LSC length much shorter than the temporal coherence length, hence suggesting that high-resolution 3D images of biological and multilayered samples can be obtained based on the low LSC. A simplified model is derived, supported by experimental results, which describes the expected interference output signal of multilayered samples when high-NA lenses are used together with a narrowband light source. An expression for the correction factor for the layer thickness determination is found valid for high-NA objectives. Additionally, the method was applied to a strongly scattering layer, demonstrating the potential of this method for high-resolution imaging of scattering media. 相似文献
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Motivated by a recent report by Dickey et al. [Phys. Med. Biol. 46, 2359 (2001)], who demonstrated optical property retrieval by using relative radiance measurements at a single position, we investigate the uniqueness of relative radiance measurements for quantifying the optical properties of turbid media by studying the solutions of the diffusion and P3 approximations of the Boltzmann transfer equation for a point source. Using the P3 approximation, we investigate the potential of radiance measurements for optical property recovery by examining the optical property response surface for point radiance information. We further derive first-order similarity relations for relative point radiance measurements and use these expressions to examine analytically the effects of noise on optical property retrieval over a wide range of optical properties typical of biological tissue. Finally, optimal experimental configurations are studied and explicit conditions for uniqueness derived that suggest potential strategies for improving optical property recovery. It is expected that point radiance measurements will prove valuable for both on-line treatment planning of minimally invasive laser therapies and optical characterization of tissues. 相似文献