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- 实验方案
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Color Reproduction Accuracy Promotion of 3D-Printed Surfaces Based on Microscopic Image Analysis
摘要： Full-color 3D printing technology is a powerful process to manufacture intelligent customized colorful objects with improved surface qualities; however, poor surface color optimization methods are the main impeding factors for its commercialization. As such, the paper explored the correlation between microstructure and color reproduction, then an assessment and prediction method of color optimization based on microscopic image analysis was proposed. The experimental models were divided into 24-color plates and 4-color cubes printed by ProJet 860 3D printer, then impregnated according to preset parameters, at last measured by a spectrophotometer and observed using both a digital microscope and a scanning electron microscope. The results revealed that the samples manifested higher saturation and smaller chromatic aberration (ΔE) after post-processing. Moreover, the brightness of the same color surface increased with the increasing soaked surface roughness. Further, reduction in surface roughness, impregnation into surface pores, and enhancement of coating transparency effectively improved the accuracy of color reproduction, which could be verified by the measured values. Finally, the chromatic aberration caused by positioning errors on different faces of the samples was optimized, and the value of ΔE for a black cube was reduced from 8.12 to 0.82, which is undetectable to human eyes.
关键词： Structural characterisation,Impregnating process,Scanning electron microscope,Image analysis,Color optimization,Full-color printing
更新于2025-11-21 11:18:25
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Alignment of liquid crystals using Langmuir?Blodgett films of unsymmetrical bent-core liquid crystals
摘要： The properties of the thin films of liquid crystal (LC) molecules can be governed easily by external fields. The anisotropic structure of the LC molecules has a large impact on the electrical and optical properties of the film. The Langmuir monolayer (LM) of LC molecules at the air–water interface is known to exhibit a variety of surface phases which can be transferred onto a solid substrate using the Langmuir?Blodgett (LB) technique. Here, we have studied the LM and LB films of asymmetrically substituted bent-core LC molecules. The morphology of LB film of the molecules is found to be a controlling parameter for aligning bulk LC in the nematic phase. It was found that the LB films of the bent-core molecules possessing defects favour the planar orientation of nematic LC, whereas the LB films with fewer defects show homeotropic alignment. The defect in LB films may introduce splay or bend distortions in the nematic near the alignment layer which can govern the planar alignment of the bulk LC. The uniform layer of LB film facilitates the molecules of nematic to anchor vertically due to a strong van der Waals interaction between the aliphatic chains leading to a homeotropic alignment.
关键词： field emission scanning electron microscope,atomic force microscope,Langmuir?Blodgett film,liquid crystals,Brewster angle microscopy,Langmuir monolayer
更新于2025-11-21 11:01:37
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[IEEE 2018 15th International Conference on Control, Automation, Robotics and Vision (ICARCV) - Singapore, Singapore (2018.11.18-2018.11.21)] 2018 15th International Conference on Control, Automation, Robotics and Vision (ICARCV) - Detection and Compensation of Motion Error for Nanomanipulation Platform in Scanning Electron Microscope
摘要： Nanomanipulation system based on scanning electron microscope(SEM) with good real-time visual feedback and nanoscale observation resolution had high operability in a vacuum working environment. Different nanomanipulation tasks of carbon nanotubes (CNTs) are carried out through the nanomanipulation system in SEM. Nanomanipulation platform existed inherent manufacture errors, installation errors and other errors, and imprecise nanomanipulation system were also time-consuming and laborious for operators. This paper presentes a method of combining the visual feedback and feedforward control to detect and compensate the motion error of the multi-dimensional SmarAct nanomanipulation platform in the nanomanipulation system in SEM. This method reduces the motion error in the X-Y direction and achieved higher operating accuracy. At the different step speed, the motion error in the X direction and Y direction is 135.7nm and 112.9nm respectively. After the feedforward compensation, the motion error in the X direction and Y direction reduces to 61.3nm and 54.1nm respectively.
关键词： feedforward control,Scanning Electron Microscope (SEM),visual feedback,nanomanipulation
更新于2025-09-23 15:23:52
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Effect of thickness and post deposition annealing temperature on the structural and optical properties of thermally evaporated molybdenum oxide films
摘要： In this paper, the influence of thickness and post deposition annealing temperature on thermally evaporated molybdenum oxide films has been studied. The X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) are used for crystal structural and surface morphological characterization of the films, respectively. The XRD analysis showed that the presence of α-MoO3 and MoO2 crystalline phase of the films annealed at elevated temperature ~ 250 °C after deposition. The optical constants are determined from UV–Vis transmission spectra. The optical band gap and Urbach energy is found to be temperature dependent. The refractive index of the films is estimated by the optical method as well as cross-sectional SEM image analysis. It is found that the refractive index of the films increases from ~ 1.70 to 2.03 with the decrease in film thickness from ~ 2.9 to 1.7 μm. It is also observed that the refractive index decreased from ~ 2.03 to 1.61 with the increase in post deposition annealing temperature from room temperature (RT) to ~ 250 °C. Moreover, extinction coefficient, optical conductivity, porosity, and film density are investigated as a function of source-substrate distance and post deposition annealing temperature. The Photoluminescence (PL) properties of the films are also investigated by recording spectra under the excitation wavelength at 250 nm.
关键词： Optical constants,Molybdenum oxide,X-ray diffraction,Thermal evaporation,Scanning electron microscope
更新于2025-09-23 15:22:29
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Temperature effect on structural, optical and NH<SUB align="right">3 gas sensing properties of TeO<SUB align="right">2 thin films
摘要： TeO2 thin films with different temperatures (400, 450 and 500°C) were deposited on glass substrates by thermal evaporation technique from a Te powder. XRD patterns indicate that as the temperature increases, the crystallisation improves. Observing the images obtained by SEM, it is seen that the grain size decreases as the temperature increases. The optical energy gap of the films was determined from transmittance and reflectance spectra. The optical energy gap decreased continuously from 3.95 eV to 3.80 eV with increasing temperature. Studying the effect of deposition temperature on NH3 gas measurement, it became obvious that as the deposition temperature increases, the sensitivity increases and the response and recovery times decrease.
关键词： scanning electron microscope,XRD,thin films,sensitivity,X-ray diffraction,energy gap,SEM,optical
更新于2025-09-23 15:22:29
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Coherent pulse beam in spin-polarized TEM using an NEA photocathode
摘要： Pulse beam emission in a spin-polarized pulse-TEM (SP-TEM) was performed using a combination of a semiconductor photocathode and an ultra-short pulse laser, which has an ability of a time-resolved measurement. The photocathode has high quantum efficiency of the order of 10-3 comparing with other metal-type photocathode, which can realize a wide range of the pulse duration from a continuous emission to a pico-second pulse emission. The SP-TEM has several advantages of a high brightness of 3.1×108 A cm-2 sr-1, a narrow energy width of 114meV and a long coherence length of 200 nm in a continuous mode. Time-resolved TEM image and pulsed interference fringes were also conducted successfully with a stroboscopic technique. Consequently, instead of a high current density, the pulsed electron beam emitted from the photocathode has enough coherence to realize a time-resolved holography that can observe phase information in a temporal space.
关键词： coherent,photocathode,pulse,electron microscope
更新于2025-09-23 15:21:21
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Characterisation of elemental analysis, carbon sulphur analysis and impact test of stent manufacturing using medical grade ASTM F75 cobalt chromium (CoCrMo) by selective laser melting (SLM) technology
摘要： This paper explains and demonstrates the capabilities of metal additive manufacturing (MAM) technology in producing intricate stent structure with a customise design by using ASTM F75 cobalt chromium powder. The elemental analysis (EDX-SEM), carbon sulphur analysis and Impact Test are being develop and tested and thus exploring the potential area of MAM process for future proof stent manufacturing. By alternatively switching to MAM, the step of production can be minimised and thus customisation of stent can be carried out according to the patient’s need. The suggested model of the stent was taken from the third-party vendor and fabrication was carried out using EOSINT M280 metal printer with the aid of Materialise Magics 19.0 software for support generation.
关键词： stent,scanning electron microscope (SEM),selective laser melting (SLM),cobalt chromium (CoCrMo),energy-dispersive X-ray spectroscopy (EDX),Metal additive manufacturing (MAM)
更新于2025-09-23 15:21:01
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Mapping Local Surface Plasmon Modes in a Nanoplasmonic Trimer Using Cathodoluminescence in the Scanning Electron Microscope
摘要： The excitability of local surface plasmon modes in radial trimers composed of gold nanorods was mapped using hyperspectral cathodoluminescence (CL) in the scanning electron microscope. In symmetric trimers, the local plasmon resonances could be excited most effectively at the ends of individual rods. Introducing asymmetry into the structure breaks the degeneracy of the dipole modes and changes the excitability of transverse dipole modes in different directions. CL in the scanning electron microscope has great potential to interrogate individual nanophotonic structures and is a complement to electron energy loss spectroscopy and optical microscopy.
关键词： scanning electron microscope,local surface plasmon mode,nanoplasmonic trimer,cathodoluminescence
更新于2025-09-23 15:21:01
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Real-time visualization of GaN/AlGaN high electron mobility transistor failure at off-state
摘要： Degradation and failure phenomena in high electron mobility transistors (HEMTs) are complex functions of electrical, thermal, and mechanical stresses as well as the quality of the device materials and their interfaces. Thus, it is difficult to predict or identify the dominant mechanism under various test protocols adopted in the literature. We propose that real-time visualization of the device microstructure can shift this paradigm. This is demonstrated by operating electron transparent AlGaN/GaN HEMTs inside a transmission electron microscope (TEM). Through the bright-field, diffraction, and energy dispersive spectroscopy techniques, we show that it is possible to characterize the lattice defects and diffusion of the various elements and thus monitor the micro-structural quality during the transistor failure. Off-state failure studies in the TEM clearly show the critical role of defects and interfaces that lead to punch-through mechanisms at the drain and even source sides. The 'seeing while measuring' approach presented in this study can be useful in pinpointing the dominant failure mechanisms and their fundamental origin.
关键词： GaN HEMTs,energy dispersive spectroscopy,lattice defects,transmission electron microscope,off-state failure,real-time visualization
更新于2025-09-23 15:21:01
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Unveiling Complex Plasmonic Resonances in Archimedean Nanospirals through Cathodoluminescence in a Scanning Transmission Electron Microscope
摘要： Metallic nanostructures with a complex plasmonic response, such as the Archimedean nanospiral (ANS) present novel ways to utilize plasmonics in modern technology [1,2]. The nanospiral can support several resonant modes, with distinct electric field profiles as shown by finite-difference time-domain (FDTD) simulations such as the hourglass (500-650nm) and focusing (650-980nm) modes [2]. In addition to the linear plasmonic response, the ANS exhibits a stronger second-order nonlinearity than seen in other metallic nanostructured systems. A high spatial-resolution picture of the plasmonic modes is critical to understanding the interactions between plasmonic modes that drive the high non-linear efficiencies [3]. Purely optical experiments struggle to observe the near field behavior of the structure due to being diffraction limited. However cathodoluminescence (CL) experiments in a scanning transmission electron microscope (STEM) create a unique opportunity for characterizing plasmonic systems with both the spatial sensitivity of electron optics and the spectral sensitivity of photonics. A significant benefit to the use of STEM-CL, as opposed to other high-resolution spectroscopy techniques such as electron energy loss spectroscopy (EELS), is that the photons generated from radiative decays in the sample are collected for signal instead of the electrons from the probe. As a result, the signal can be manipulated and filtered using standard optical techniques, allowing us to map difficult to observe plasmon modes and even give insight into the polarization of their radiative decay. To experimentally observe the plasmon modes, an Au ANS array is fabricated using electron-beam lithography on a 50 nm silicon nitride film supported by a silicon substrate. A 500μm x500 μm window is then backside-etched beneath the array. STEM-CL is done in a VG-HB601 STEM operated at 60 kV with a home-built CL spectrometer system. Radiative emission is collected with a parabolic mirror and reflected out of a port in the side of the microscope, allowing the signal to be filtered and polarized using standard optical equipment, and ultimately collected in a photomultiplier tube (PMT). First, the focusing mode (650-980nm) is examined. Fig 1a shows a FDTD simulation of the plasmon mode. Fig 1b shows a high angle annular dark field (HAADF) image of the fabricated ANS on the SiN window. The raw CL intensity is shown in Fig 1c with no spectral filtering. Emission from all plasmonic modes, interband transitions, and any other radiative decay pathways are all simultaneously detected. However, by spectrally filtering the CL signal, individual modes can be isolated. The focusing mode is predicted to be strongest in the 650-980 nm region, so by using a 600 nm long-pass spectral filter, the radiative decay from other optical features can be eliminated, and a map of the focusing mode (Figure 1d) can be obtained. For the hourglass mode, however, spectral filters cannot be used to observe the spatial profile of the plasmonic resonance, because unlike the focusing mode, the hourglass mode has a distinct polarization axis that is parallel to the axis of the exciting optical pulse, as shown in the FDTD simulation in Fig 1e. With no polarization selectivity on electron-optics, the hourglass plasmon modes can be excited in all in-plane axes of the ANS simultaneously within the STEM, and no individual plasmon can be isolated and detected. However, since the hourglass mode has a strong polarization dependence on the exciting pulse, it is likely that the resulting emission is similarly polarized. In Fig 1f the HAADF image of an ANS is shown, and Fig 1g shows the unfiltered CL image. Fig 1h shows CL image filtered with a linear polarizer and exhibits a similar spatial profile to the simulation in Fig 1e, demonstrating that the modes that have a have a strong dependence on the polarization of the exciting optical source also exhibit a polarization dependence on their radiative decay. Nanostructures with complex, nonlinear plasmonic responses, such as the ANS, have unique optical attributes not present in simpler geometries. As a result, high spatial-resolution techniques to investigate the near-field profiles are an important avenue of plasmonic investigation. STEM-CL presents a particularly unique opportunity to combine photon and electron optics in order to characterize and map plasmonic modes, such as the hourglass and focusing modes of the ANS, with nanoscale precision.
关键词： nonlinearity,cathodoluminescence,scanning transmission electron microscope,Archimedean nanospiral,plasmonics
更新于2025-09-23 15:19:57