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[en] Brain images acquired using the diffusion-weighted imaging (DWI) method indicate that the diagnostic efficiency of infarction improves and the noise increases as the b-value increases. In this study, we designed a fast nonlocal means (FNLM) noise reduction algorithm and evaluated its effectiveness for de-noising brain images with high b-values. The designed algorithm uses an approach that measures the similarity of local parts in an image, calculates weights based on the result, and uses the principle of reducing processing time using a simplification of the calculation. To demonstrate the effectiveness of the algorithm, we compared the qualities of the images obtained using FNLM with those obtained using previously developed algorithms with noise reduction performance and no-reference image-quality assessment parameters. The results of applying the FNLM noise reduction algorithm to DWI images obtained at high b-values indicated superior quantitative characteristics. In particular, the signal-to-noise ratio, coefficient of variation, and blind/referenceless image spatial quality evaluator (BRISQUE) results using the proposed FNLM algorithm were approximately 1.84, 1.44, and 1.21 times better than those of the noisy image, respectively. In conclusion, our results verified that the FNLM approach achieves higher noise reduction efficiency in diffusion-weighted magnetic resonance imaging.
[en] In order to measure the energy spectra of secondary neutrons in proton and heavy-ion radiotherapy, a neutron spectrometer has been developed. In this paper, two organic scintillation detectors combined with photomultiplier tubes were used to form a dual-scintillator time-of-flight spectrometer. The performance of this spectrometer was tested with a DT neutron generator, and the detection efficiency of each detector as well as the spectrometer were simulated by Geant4 toolkit. It's shown that the time resolution of the spectrometer is 0.797 ns with an energy resolution of 26.4% for neutrons with an energy of 14 MeV at a flight distances over 150 cm. (author)
[en] We report experiments in which radiatively metastable 2 S positronium (Ps) atoms entered a waveguide whose internal surfaces were lined with smoked magnesium oxide (MgO) powder. The waveguide was built such that time-delayed microwave radiation pulses, tuned to drive 2 S→2 P transitions, could be applied to the Ps ensemble. The lifetime of 2 S atoms was measured using time-delayed microwave induced decay, yielding ≈200 ns. This is considerably shorter than the Zeeman shifted lifetime of 1070 ns, indicating that Ps atoms in the 2 S state do not survive multiple collisions with MgO nanocrystals.
[en] When evolution algorithms are used to unfold the neutron energy spectrum, fitness function design is an important fundamental work for evaluating the quality of the solution, but it has not attracted much attention. In this work, we investigated the performance of eight fitness functions attached to the genetic algorithm (GA) and the differential evolution algorithm (DEA) used for unfolding four neutron spectra selected from the IAEA 403 report. Experiments show that the fitness functions with a maximum in the GA can limit the ability of the population to percept the fitness change, but the ability can be made up in the DEA. The fitness function with a feature penalty term helps to improve the performance of solutions, and the fitness function using the standard deviation and the Chi-squared result shows the balance between the algorithm and the spectra. The results also show that the DEA has good potential for neutron energy spectrum unfolding. The purposes of this work are to provide evidence for structuring and modifying the fitness functions and to suggest some genetic operations that should receive attention when using the fitness function to unfold neutron spectra.
[en] This paper describes the implementation of a computationally efficient embedded system on an Field Programmable Gate Array (FPGA) platform for real-time brain activity estimation with multiple channels. The brain signals from multiple channels are considered as output of independent linear systems with unknown parameters representing the brain activity in corresponding channels. Multiple adaptive Recursive LeastSquares Estimation (RLSE) cores are implemented in FPGA to independently estimate the brain activity in each channel concurrently. The proposed RLSE-FPGA system provides dedicated (no time or resource sharing) and parallel processing environment. The universal asynchronous receiver transmitter core is also developed to communicate the measured and estimated parameters supported by storage facility programmed as shared memory. The computational precision is guaranteed by deploying a 32-bit floating point core for all the variables. The validation carried out by real Functional Near-Infrared Spectroscopy dataset and comparative analysis with the previously reported result, demonstrates the effectiveness of the proposed system. The computational cost endorses the effectiveness of concurrent processing of multiple channels data in a sample before the arrival of the next sample. The proposed methodology has potential in real-time medical, military and industrial applications. (author)
[en] The Nuclear Science and Instrumentation Laboratory (NSIL) is integrated into the Physics Section, Division of Physical & Chemical Sciences, Department of Nuclear Sciences and Applications. It provides expertise, training and support in the effective utilization of nuclear instrumentation and analytical techniques in a broad range of applications, with a focus on mobile radiation monitoring, X-ray spectrometry, accelerator technologies, and more recently on compact neutron generators. For 20 years our laboratory has issued the X-ray Fluorescence - XRF Newsletter with the objective to exchange knowledge and competencies with nuclear analytical laboratories in the IAEA Member States on developments in fundamentals and applied aspects of X-ray spectrometry. With the broadening of NSIL activities, and also of the Physics Section, the scope of the Newsletter is being enlarged to cover the full scope of NSIL activities. For this reason, the name is changed to Nuclear Science and Instrumentation Newsletter. This new version of the newsletter is longer than usual, as it covers the breadth of NSIL activities and capacity and gives reports from Member States. Capacity building for Members States is one of the major activities of the laboratory. NSIL is a leading training hub on topics related to nuclear instrumentation, XRF analysis, mobile radiation monitoring techniques, accelerator technology and applications, as well as radiotracers and radiation technology applications. Key areas of development and application of the laboratory include mobile radiation monitoring, elemental analysis using XRF and accelerator technology and applications are further detailed in this issue.
[en] Every image display system for medical diagnosis purposes must meet minimum quality criteria. There are recommendations in the specialized literature for quality control tests that can be performed on medical displays. This study aimed to evaluate luminance and the Grayscale Standard Display Function (GSDF) in primary medical monitors and conventional (commercial) monitors. The values of minimum and maximum luminance, luminance ratio and data for obtaining the GSDF calibration curve were collected on 17 monitors. Of the 17 monitors evaluated, 09 were primary and 08 were commercial monitors. The study showed that, regardless of their purpose (primary or commercial), none of the 17 monitors evaluated met the minimum Luminance recommendations, whose expected values are at least 1.0 cd/m2 for primary monitors, 1.2 cd/m2 on primary monitors dedicated to mammography and 0.8 cd/m2 on commercial monitors. Regarding the maximum luminance, 04 of the 08 commercial monitors evaluated did not reach the recommendation of 170 cd / m² for this category and in the category of primary monitors, the 3 MP EIZO monitor did not reach this value either. The Luminance ratio was above that stipulated in all evaluated monitors. In the evaluation of the GSDF characteristic curve, only the BARCO 5 MP and Beacon G52P + primary monitors obtained values within the 10% tolerance. (author)
[en] The present study is devoted to an investigation of the (n, p) and the (n, α) modifications created by neutrons in AlN nanoparticles at different energies using computer modeling. The possible modifications under the influence of neutrons have been separately studied for the Al and the N atoms that forming AlN nanoparticles. Because the effective cross sections of the probable modifications are different in the various types of aluminum and nitrogen atoms, the modeling was performed separately for each stable isotope. The effective cross section spectra for the (n, p) and (n, α) modifications for the Al and the N atoms were mutually studied.
[en] The main objective of this study was to assess the molecular simulation of the design of carbon dioxide (CO2) and to construct infrared optical filters for the transmission and absorption of the CO2 laser and the emission of gaseous CO2 radiation. Semiconductor compounds used to determine the wavelength of infrared transmission and absorption infrared radiation (IR) to produce an IR filter for laser production and gas emission using the Fourier Transform infrared spectrometer (FT-RI) for research purposes. Carbon dioxide molecule simulation has been used based on Hyper 6 simulation programme in potential energy, and kinetic energy, which measures the infrared radiation spectrum. Infrared filters are constructed from the compounds of a semiconductor of Zinc Sulfide supplied (ZnS), Aluminum Oxide (Al2O3), Magnesium Oxide (MgO), Lead (II) Sulfide (PbS), and Potassium Chloride (KCl). The data used for evaluation of the optical elements in the IR region based on the transmission and absorption of radiation intensity effective for wavelength detection. The assessment of the detection is indicating transmission and absorption of the wavelengths of CO2 laser and CO2 gas molecule under investigation. This study has identified the approach of the result of transmission and absorption of the peak intensities of 10.6, 2.7, 4.3 and 15μm of CO2 laser and gas radiation emission of the filters in the IR region. The findings of this study have a number of important applications in the IR radiation region. (author)
[en] Soil moisture is an essential parameter for water management. Currently, three methods for soil moisture estimating are used: in-situ point measurements, remote sensing-based methods, and land surface models. Recently, as a passive nuclear technology, the cosmic-ray neutron probe, an innovative in-situ instrument, has been developed. The probe provides area-averaged and spatial estimates of soil moisture at area-wide scale of about 20 hectares at a measurement depth up to 72 cm. This instrument bridges the gap between in-situ point measurements and global satellite-based soil moisture estimates. A single cosmic-ray neutron probe can replace a network of conventional in-situ instruments to provide reliable soil moisture estimates. Three types of cosmic-ray neutron probe devices exist: stationary, mobile backpack and vehicle mounted roving. The reliable, accurate and continuous soil moisture estimates provided by the cosmic-ray neutron probe over large scale makes it very attractive for researchers and engineers in diverse fields. (author)