共查询到20条相似文献,搜索用时 15 毫秒
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Liang Liang Jiandong Yuan Guozhi Lin 《The International Journal of Advanced Manufacturing Technology》2020,107(1):97-107
As the field of biomedicine continues to grow, so will the need for the quick and efficient manufacture of high-quality micro-textures, such as microfluidi 相似文献
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基于连续扫描方式的激光共焦扫描显微镜的研制 总被引:2,自引:2,他引:0
研发了一套基于连续扫描的激光共焦扫描显微镜(laser confocal scanning microscopy,LCSM)系统。该系统采用工作台连续运动方式实现扫描,提出了利用单次采集的数据滤除随机噪声的方法,避免了多帧取平均对成像速度造成的影响。实现连续扫描的关键在于解决工作台运动与数据采集的同步问题,利用采集卡有限采集模式,合理匹配工作台参数和采集参数,成功解决了这一问题。详细介绍了影响分辨率的因素,通过合理选取探测器针孔直径,取样间隔,确保了实现高分辨率的要求。系统利用Visual C#开发的控制平台,成功地对生物细胞进行了扫描成像。实验结果表明:基于连续扫描的LCSM具有较高的分辨率,生成的显微图像没有任何畸变,并且成像速度有了大幅度提高。 相似文献
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Seungwon Shin 《Journal of Mechanical Science and Technology》2012,26(10):3141-3148
Bubble rising phenomenon is widely found in many engineering applications including stream generators in power plants. Many experimental and numerical researches have been performed to predict the dynamic behavior of the bubble rising process. Most simulations so far have focused on evolution behavior of the rising bubble itself. Rising bubbles could penetrate through the top free surface which makes the problem much more complicated in addition to the curvature effect on the interface. With top surface, satellite droplets may be generated near breakup region and entrained to rising velocity field. In this paper, the effect of top free surface on rising bubble has been numerically investigated. High-order tetra-marching level contour reconstruction method (LCRM), which is a hybridization of fronttracking and level-set methods has been used to track the gas-liquid interface explicitly. Effects of free surface on the interfacial shape and behavior after breakup are studied with different size and depth of the initial bubble. It has been found that the initial diameter of the bubble is the dominant factor controlling the satellite droplet formation. 相似文献
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Seungwon Shin 《Journal of Mechanical Science and Technology》2009,23(7):1795-1800
Direct numerical simulation of multiphase flow on fixed Eulerian grid became increasingly popular due to its simplicity and
robustness. Some of the well-known methods include VOF, Level Set, Phase field, and Front Tracking method. Lately, hybridization
of above methods gets its attention to overcome the disadvantages pertaining to each method. One hybrid approach developed
by the author is the Level Contour Reconstruction Method (LCRM) which combines characteristics of both Front Tracking and
Level Set method. Many engineering problems also contain complex geometry as boundary condition and proper representation
of grid structure plays very important role for the successful outcomes. In this paper, an algorithm for handling arbitrary
geometry inside fixed Eulerian computational domain with multiphase flow has been presented. Interface reconstruction between
liquid and vapor phase has been performed outside of arbitrary solid boundary explicitly along with dynamic contact angle
model. Sharp interface technique using ghost fluid point extrapolation method has been utilized for correct implementation
of no-slip boundary condition at the wall.
This paper was presented at the 7th JSME-KSME Thermal and Fluids Engineering Conference, Sapporo, Japan, October 2008.
Seungwon Shin received his B.S. and M.S. degree in Mechanical Engineering from Seoul National University, Korea, in 1995 and 1998, respectively.
He then received his Ph.D. degree from Georgia Tech in 2002. Dr. Shin is currently a Professor at the School of Mechanical
and System Design Engineering at Hongik University in Seoul, Korea. Dr. Shin’s research interests include computational fluid
dynamics, multiphase flow, surface tension effect, phase change process. 相似文献
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Fowzia S. Alamro Arafat Toghan Hoda A. Ahmed Ayman M. Mostafa Abbas I. Alakhras Eman A. Mwafy 《Microscopy research and technique》2022,85(4):1611-1617
A simple procedure was used to generate and decorate leather structures with different amounts from zinc oxide (ZnO) nanoparticles to produce multifunctional leather structure by pulsed laser ablation method in liquid media based on changing the ablation time in just one-pot method. The impact of varying concentrations of ZnO nanoparticles embedded on the surface of leather on water resistance, water vapor permeability, mechanical characteristics, and UV-shielding efficiency was examined by different characterization techniques like X-ray diffraction, surface area, UV–visible spectroscopy, scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy, and thermogravimetric analysis. The results showed that the combination between the external functional groups of leather with ZnO nanoparticles was discovered. ZnO nanoparticles effectively coated the surface of leather tissue, as seen by SEM images, and their form a spherical morphology. Leather with ZnO nanoparticles added had the highest capacity to kill Escherichia coli bacteria, exceeding leather without modification and ZnO nanoparticles alone in 50-hr incubation. In addition, the incubation period had a substantial impact on the suppression of Staphylococcus aureus bacteria growth by leather samples. 相似文献
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The scanning multi-component pulsed laser deposition (PLD) method realizes uniform depositions of desired coatings by a modified pulsed laser deposition process, preferably with a femto-second laser-system. Multi-component coatings (single or multilayered) are thus deposited onto substrates via laser induced ablation of segmented targets. This is achieved via horizontal line-scanning of a focused laser beam over a uniformly moving target's surface. This process allows to deposit the desired composition of the coating simultaneously, starting from the different segments of the target and adjusting the scan line as a function of target geometry. The sequence and thickness of multilayers can easily be adjusted by target architecture and motion, enabling inter/intra layer concentration gradients and thus functional gradient coatings. This new, simple PLD method enables the achievement of uniform, large-area coatings. Case studies were performed with segmented targets containing aluminum, titanium, and niobium. Under the laser irradiation conditions applied, all three metals were uniformly ablated. The elemental composition within the rough coatings obtained was fixed by the scanned area to Ti-Al-Nb = 1:1:1. Crystalline aluminum, titanium, and niobium were found to coexist side by side at room temperature within the substrate, without alloy formation up to 600 °C. 相似文献
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In the laser scanning analyser a laser beam is reflected from a rotating polygonal mirror so as to scan the workpiece surface at high speed, where it is again reflected into a photodetector which measures the reflected intensity. If the surface is rough, in addition to the specular reflectance the diffuse reflectance due to diffraction is measured as a function of the off-specular angle. In effect the system when used in this mode is a glossmeter which measures the optical properties of a section through the surface and is thus highly suitable for comparison with a stylus instrument. Experiments are described in which reflectance measurements on surfaces finished by various machining processes are compared with stylus roughness measurements. It is found that reflectance measurements are sensitive both to roughness and to the orientation of the lay. Reflectance measurements are found to vary as the average roughness and as the fourth power of the profile slope. There is no correlation with curvature and no evidence of the effect of longer surface wavelengths. There is some evidence that two different scattering mechanisms are involved. Possible applications of such a real-time non-contacting roughness measuring system are described. 相似文献
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Laser scanning confocal microscopes are essential and ubiquitous tools in the biological, biochemical and biomedical sciences, and play a similar role to scanning electron microscopes in materials science. However, modern laser scanning confocal microscopes have a number of advantages for the study of materials, in addition to their obvious uses for high resolution reflected and transmitted light optical microscopy. In this paper, we provide several examples that exploit the laser scanning confocal microscope's capabilities of pseudo-infinite depth of field imaging, topographic imaging, photo-stimulated luminescence imaging and Raman spectroscopic imaging. 相似文献
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Direct measurement of glutathione in epidermal cells of intact Arabidopsis roots by two-photon laser scanning microscopy 总被引:1,自引:0,他引:1
Two-photon laser scanning microscopy (TPLSM) was used to directly measure glutathione (GSH) as its fluorescent glutathione S-bimane conjugate (GSB) in developing root hair cells (trichoblasts) and non-root hair cells (atrichoblasts) of intact Arabidopsis roots. In comparison to confocal microscopy, TPLSM showed more detail deep within the tissue with less signal attenuation. The total level of GSB labelling reached a plateau after 60 min in both trichoblasts and atrichoblasts, reflecting depletion of GSH. GSB was formed initially in the cytoplasm and was subsequently transported into the vacuole. The volume ratio of vacuole to cytoplasm was determined using the Cavalieri estimator of volume and used to calculate the amount of GSB per volume of cytoplasm in each cell type. At the end of the time-course the cytoplasmic concentration of GSB was 2.7 ± 0.5 m m ( n = 5) in trichoblasts and 5.5 ± 0.8 m m ( n = 5) in atrichoblasts. In trichoblasts this value represents the initial concentration of GSH in the cytoplasm. Labelling of roots with monochlorobimane (MCB) on ice led to the formation of GSB in the cytoplasm, but prevented vacuolar sequestration. After washing prelabelled roots and transfer to room temperature, vacuolar transport resumed. Although no free MCB was present the total amount of GSB in atrichoblasts increased further, indicating that the higher values recorded in the atrichoblasts might reflect additional symplastic transport and sequestration of GSB from neighbouring cells. 相似文献
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A. G. Poleshchuk R. A. Sametov A. G. Sedukhin 《Optoelectronics, Instrumentation and Data Processing》2012,48(4):327-333
A new version of the method of direct multibeam laser writing of diffractive optical elements (DOE) is proposed and investigated. A writing area in the form of an array of focused light spots is formed by splitting the writing laser beam into multiple beams by using a Dammann grating and focusing of these beams in the plane of a moving carrier with a photosensitive material. Adjustment of the radial pitch of writing and correction of the uniformity of the beam intensity is carried out by tilting the Dammann grating and displacing it in the dispersion direction. In writing DOEs, the radial pitch of discrete displacement of the writing area with respect to the plane of the DOE is set equal to or multiple of the average radial distance between the radial projections of the centers of the focused light spots. This version provides improved performance and accuracy due to high-quality paralleling of the writing beam and the averaging effect in superimposed writing. 相似文献
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干涉型激光直写制作光学可变图像的优化方法 总被引:12,自引:1,他引:12
分析了用干涉型激光直写技术制作光学可变图像的优点,为达到最佳图像质量和最短运行时间,针对不同类型的图像提出光刻轨迹按光栅取向连续曝光和控制光电开关的通断不连续曝光的两种优化运行式,并给出了实验比较结果。 相似文献
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Y. SAKO A. SEKIHATA Y. YANAGISAWA M. YAMAMOTO Y. SHIMADA K. OZAKI & A. KUSUMI 《Journal of microscopy》1997,185(1):9-20
Two-photon excitation laser scanning fluorescence microscopy (2p-LSM) was compared with UV-excitation confocal laser scanning fluorescence microscopy (UV-CLSM) in terms of three-dimensional (3-D) calcium imaging of living cells in culture. Indo-1 was used as a calcium indicator. Since the excitation volume is more limited and excitation wavelengths are longer in 2p-LSM than in UV-CLSM, 2p-LSM exhibited several advantages over UV-CLSM: (1) a lower level of background signal by a factor of 6–17, which enhances the contrast by a factor of 6–21; (2) a lower rate of photobleaching by a factor of 2–4; (3) slightly lower phototoxicity. When 3-D images were repeatedly acquired, the calcium concentration determined by UV-CLSM depended strongly on the number of data acquisitions and the nuclear regions falsely exhibited low calcium concentrations, probably due to an interplay of different levels of photobleaching of Indo-1 and autofluorescence, while the calcium concentration evaluated by 2p-LSM was stable and homogeneous throughout the cytoplasm. The spatial resolution of 2p-LSM was worse by 10% in the focal plane and by 30% along the optical axis due to the longer excitation wavelength. This disadvantage can be overcome by the addition of a confocal pinhole (two-photon excitation confocal laser scanning fluorescence microscopy), which made the resolution similar to that in UV-CLSM. These results indicate that 2p-LSM is preferable for repeated 3-D reconstruction of calcium concentration in living cells. In UV-CLSM, 0.18-mW laser power with a 2.φ pinhole (in normalized optical coordinate) gives better signal-to-noise ratio, contrast and resolution than 0.09-mW laser power with a 4.9-φ pinhole. However, since the damage to cells and the rate of photobleaching is substantially greater under the former condition, it is not suitable for repeated acquisition of 3-D images. 相似文献