Development of a high-speed, phase-sensitive laser probe system for RF surface/bulk acoustic wave devices with an autofocus function for long time continuous operation

This paper describes the implementation of the autofocus function for the laser beam into the high-speed, phase-sensitive laser probe system for RF SAW/BAW devices. This implementation can compensate defocus caused during continuous measurements that take dozens of hours. After a brief explanation of the system used in this work, detailed discussion is given on an employed evaluation function indicating focus status, which is a key factor determining autofocus reliability. It is shown that the sum of energy of Laplacians is suitable as the evaluation function, which can be calculated by the image of the probing laser spot captured by a build-in CCD camera. Then, the implementation of the autofocus function into the current system is detailed. It is confirmed that this function can adjust the focus within almost ±20 μm defocus conditions. Finally, it is confirmed how the implemented autofocus function works effectively to keep just-in-focus under the disturbance.

Deep Learning based Tomato’s Ripe and Unripe Classification System

Effective productivity estimates of fresh produced crops are very essential for efficient farming, commercial planning, and logistical support. In the past ten years, machine learning (ML) algorithms have been widely used for grading and classification of agricultural products in agriculture sector. However, the precise and accurate assessment of the maturity level of tomatoes using ML algorithms is still a quite challenging to achieve due to these algorithms being reliant on hand crafted features. Hence, in this paper we propose a deep learning based tomato maturity grading system that helps to increase the accuracy and adaptability of maturity grading tasks with less amount of training data. The performance of proposed system is assessed on the real tomato datasets collected from the open fields using Nikon D3500 CCD camera. The proposed approach achieved an average maturity classification accuracy of 99.8 % which seems to be quite promising in comparison to the other state of art methods.

Optical Fiber Bundle-Based High-Speed and Precise Micro-Scanning for Image High-Resolution Reconstruction

We propose an imaging method based on optical fiber bundle combined with micro-scanning technique for improving image quality without complex image reconstruction algorithms. In the proposed method, a piezoelectric-ceramic-chip is used as the micro-displacement driver of the optical fiber bundle, which has the advantages of small volume, fast response speed and high precision. The corresponding displacement of the optical fiber bundle can be generated by precise voltage controlling. An optical fiber bundle with core/cladding diameter 4/80 μm and hexagonal arrangement is used to scan the 1951 USAF target. The scanning step is 1 μm, which is equivalent to the diffraction limit resolution of the optical system. The corresponding information is recorded at high speed through photo-detectors and a high-resolution image is obtained by image stitching processing. The minimum distinguishable stripe width of the proposed imaging technique with piezoelectric-ceramic-chip driven micro-scanning is approximately 2.1 μm, which is 1 time higher than that of direct imaging with a CCD camera whose pixel size is close to the fiber core size. The experimental results indicate that the optical fiber bundle combined with piezoelectric-ceramic-chip driven micro-scanning is a high-speed and high-precision technique for high-resolution imaging.

Three-dimensional tomographically reconstructed optical emission profiles of Hall thruster plasmas

A diagnostic system was developed for spectrally resolved, three-dimensional tomographic reconstruction of Hall thruster plasmas, and local intensity profiles of Xe I and Xe II emissions were reconstructed. In this diagnostic system, 28 virtual cameras were generated using a single, fixed charge-coupled device (CCD) camera by rotating the Hall thruster to form a sufficient number of lines of sight. The Phillips-Tikhonov regularization algorithm was used to reconstruct local emission profiles from the line-integrated emission signals. The reconstruction performance was evaluated using both azimuthally symmetric and asymmetric synthetic phantom images including 5% Gaussian white noise, which resulted in a root-mean-square error of the reconstruction within an order of 10-3 even for a 1% difference in the azimuthal intensity distribution. Using the developed system, three-dimensional local profiles of Xe II emission (541.9 nm) from radiative decay of the excited state 5p4(3P2)6p2[3]˚5/2 and Xe I emission (881.9 nm) from 5p5(2P˚3/2)6p2[5/2]3 were obtained, and two different shapes were found depending on the wavelength and the distance from the thruster exit plane. In particular, a stretched central jet structure was distinctively observed in the Xe II emission profile beyond 10 mm from the thruster exit, while gradual broadening was found in the Xe I emission. Approximately 10% azimuthal nonuniformities were observed in the local Xe I and Xe II intensity profiles in the near-plume region (< 10 mm), which could not be quantitatively distinguished by analysis of the frontal photographic image. Three-dimensional Xe I and Xe II intensity profiles were also obtained in the plume region, and the differences in the structures of both emissions were visually confirmed.

In-situ leading-edge-induced damages of melting and cracking on W/Cu monoblocks as divertor target during long-term operations in EAST

Leading-edge-induced thermal loading effect due to assembly tolerance between neighboring castellated plasma facing components is a critical issue in fusion devices. Actively-cooled ITER-like W/Cu monoblocks were successfully installed for upper divertor target in EAST which significantly increases the ability of divertor power exhaust. The misalignment between neighboring monoblocks was formed inevitably during manufacturing and assembly processes, providing a possibility to demonstrate the leading-edge-induced thermal damages. Indeed, the leading-edge-induced melting phenomena of W/Cu monoblocks on upper divertor targets were observed during plasma discharges with a large number of droplets ejected from divertor target using CCD camera, which were also identified at the leading edges of W/Cu monoblocks. Not only that, but also many macro cracks with width of ~70 m and depth of < 5 mm along radial and toroidal directions were also found universally at the leading edges of W/Cu monoblocks by post-mortem inspection after plasma campaigns. Thermal-mechanical analysis by means of the finite element simulation demonstrated that the maximum temperature could reach W melting point under current projected heat load of ~3 MWm-2 on flat top surface with large misalignment up to 3 mm at the leading edges. Meanwhile, the high temperature also induced high thermal stress and strain concentration at the center of leading edges, at which the thermal fatigue cracking could be initially generated. Such kind of cracks at leading edges on W/Cu monoblocks may be unavoidable due to the long-term pulsed fatigue effects. However, the influence of these cracks seems to be acceptable thanks to the limited propagated distance by self-castellation effect, which still need long-term tracking. The in-situ leading-edge-induced damages of melting and cracking on W/Cu monoblocks of EAST upper divertor target provide significant reference to understand the leading-edge-induced thermal effect in ITER and future fusion devices.

Analysis of Proteins by Immunoblotting

In immunoblotting (western blotting), proteins are first separated by SDS-PAGE and then transferred electrophoretically from the gel onto a support membrane that binds proteins tightly. After the unreacted binding sites of the membrane are blocked to suppress nonspecific adsorption of antibodies, the immobilized proteins are reacted with a specific polyclonal or monoclonal antibody. Antigen–antibody complexes are visualized using chromogenic, fluorescent, or chemiluminescent reactions. Immunoblotting protocols are reagent specific and, owing to the wide assortment of equipment, reagents, and antibodies available, highly diverse. Presented here is an example of a workable protocol for developing a blot using horseradish peroxidase (HRP)–conjugated secondary antibody and enhanced chemiluminescence (ECL). ECL is based on the emission of light during the HRP-catalyzed oxidation of luminal or other substrates. Emitted light is captured on film or by a CCD camera, for qualitative or semiquantitative analysis. Because ECL is so sensitive, it has become a popular detection method. This protocol can be modified for different membranes, antibodies, and detection systems. Optimal dilutions of the primary and secondary antibodies need to be determined empirically, but recommendations provided by the manufacturer are usually a good starting point.

Improvements in Smartphone and Night Vision Imaging Technologies Enable Low Cost, On-Site Assays of Bioluminescent Cells

Technologies enabling on-site environmental detection or medical diagnostics in resource-limited settings have a strong disruptive potential compared to current analytical approaches that require trained personnel in laboratories with immobile, resource intensive instrumentation. Handheld devices, such as smartphones, are now routinely produced with CPUs, RAM, wireless data transfer capabilities, and high-resolution complementary metal oxide semiconductor (CMOS) cameras capable of supporting the capture and processing of bioluminescent signals. In theory, combining the capabilities of these devices with continuously bioluminescent human cell-based bioreporters would allow them to replicate the functionality of more expensive, more complex, and less flexible platforms while supporting human-relevant conclusions. In this work, we compare the performance of smartphone (CMOS) and night vision (image intensifier) devices with in vivo (CCD camera), and in vitro (photomultiplier tube) laboratory instrumentation for monitoring signal dynamics from continuously bioluminescent human cellular models under toxic, stable, and induced expression scenarios. All systems detected bioluminescence from cells at common plating densities. While the in vivo and in vitro systems were more sensitive and detected signal dynamics representing cellular health changes earlier, the night vision and smartphone systems also detected these changes with relatively similar coefficients of variation and linear detection capabilities. The smartphone system did not detect transcriptional induction. The night vision system did detect transcriptional activation, but was less sensitive than the in vivo or in vitro systems and required a stronger induction before the change could be resolved.

Large size growth of terbium doped BaCl2/NaCl/KCl eutectic for radiation imaging

In this study, a large-size eutectic scintillator of Tb-doped BaCl2/NaCl/KCl was grown using the Czochralski (Cz) and halide vertical Bridgman methods (H-VB). The suitability of these two growth methods for growing the eutectic was compared. Finally, 1 diameter eutectic bulks were obtained using the H-VB method. The Tb3+-derived strongest intensity peak at approximately 550 nm was observed by X-ray irradiation. An approximately 3 × 3 mm transparent eutectic plate was cut and polished from the grown eutectic bulk. An α-ray imaging test was performed using the eutectic plate, a fiber optic plate, and an electron-multiplying CCD camera. The resolution performance for radiation-imaging applications was evaluated.

A 3D RANGE MODULATOR FOR ULTRA-SHORT PROTON FLASH IRRADIATION

Background and aims In the pursuit of optimal parameters for FLASH irradiation, all components involved in the beam delivery should be compatible with requirements spread in an extreme and wide unexplored regime. Aiming for minimal total irradiation times with modulated proton beams, which deliver a flat depth-dose distribution along tumors, a static range modulator has been developed to accommodate ultra-short beam durations regardless of their time structure. The design goals were set to match the functionality of the rotating wheel used for in-vivo and in-vitro FLASH investigations at HZB. Methods Having the form of a ridge filter extended to an additional dimension, a hexagonal-pyramid pattern was configured to an incoming beam of 23 MeV energy with > 1 mm radius, in order to create a 6 mm uniform field with a flat dose range of 5 mm at the target. The manufacturing was done with a 3D printer using VeroWhite, a material similar to PMMA. The lateral and distal dose distribution of both modulators were measured using a Markus Chamber (PTW-Freiburg, Germany) in a water phantom and a radioluminescent screen mounted in front of CCD camera, respectively. Results The developed modulator created very flat dose distributions as designed, with negligible differences to the reference rotating wheel. The positioning tolerances were evaluated as relatively relaxed, with offsets of 2 cm and an angle of 5 degrees not compromising the desired performance. Conclusions The developed static modulator allows systematic proton FLASH studies on small organs using a broad range of timing schemes, disentangled from temporal and spatial incoherencies.