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A high power laser facility to conduct annealing tests at high temperature
摘要： The knowledge of material properties and their behavior at high temperatures is of crucial importance in many fields. For instance, annealing phenomena occurring during the thermomechanical processing of materials, such as recrystallization, have long been recognized as being both of scientific interest and technological importance. Different methods are currently used to study annealing phenomena and submit metals to heat loads. In this work, we present the design and the development of a laser-based facility for annealing tests. This experimental setup enables studies at the laboratory scale with great flexibility to submit samples to various spatial and temporal heating profiles. Due to the possibility of having optical access to the sample, laser heating can be combined with several non-contact diagnostics such as infrared imaging to control and analyze the temperature gradients. As a case study, we present a set of experiments performed to study the recrystallization kinetics of tungsten. We demonstrate that samples can be heated linearly with heating rate up to ～2000 K/s, at temperatures above 2000 K, for seconds or hours, with typical errors in the temperature measurement of around 1% that depend mainly on the determination of sample emissivity. Such studies are of crucial interest in the framework of nuclear fusion since the international thermonuclear experimental reactor nuclear reactor will operate with a full-W divertor.
关键词： tungsten,laser annealing,nuclear fusion,high temperature,recrystallization
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Singapore, Singapore (2019.8.28-2019.8.30)] 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Spectral Engineering of Photonic Filters Based on Mode Splitting in Self-Coupled Silicon Nanowire Waveguides
摘要： Recently, position-patch-based face hallucination methods have received much attention, and obtained promising progresses due to their effectiveness and ef?ciency. A locality-constrained double low-rank representation (LCDLRR) method is proposed for effective face hallucination in this paper. LCDLRR attempts to directly use the image-matrix based regression model to compute the representation coef?cients to maintain the essential structural information. On the other hand, LCDLRR imposes a low-rank constraint on the representation coef?cients to adaptively select the training samples that belong to the same subspace as the inputs. Moreover, a locality constraint is also enforced to preserve the locality and the sparsity simultaneously. Compared with previous methods, our proposed LCDLRR considers locality manifold structure, cluster constraints, and structure error simultaneously. Extensive experimental results on standard face hallucination databases indicate that our proposed method outperforms some state-of-the-art algorithms in terms of both visual quantity and objective metrics.
关键词： low-rank representation,position-patch,Face hallucination,nuclear norm
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE International Conference on Computation, Communication and Engineering (ICCCE) - Fujian P.R, China (2019.11.8-2019.11.10)] 2019 IEEE International Conference on Computation, Communication and Engineering (ICCCE) - The IR Drop Effect of 2T1C and 3T1C Driving Modes in Top Emission AMOLED
摘要： The immune system in homo sapiens protects the body against diseases by identifying and attacking foreign pathogens. However, when the system misidenti?es native cells as threats, it results in an auto-immune response. The auto-antibodies generated during this phenomenon may be identi?ed through the indirect immuno?uorescence test. An important constituent process of this test is the automated identi?cation of antigen patterns in the cell images, which is the focus of this research. We perform a detailed literature review and present a framework to automate the identi?cation of antigen patterns. The ef?cacy of the framework, demonstrated on the MIVIA ICPR 2012 HEp-2 Cell Contest and SNP HEp-2 Cell datasets, suggests that the algorithm is comparable with the state-of-the-art approaches.
关键词： anti-nuclear antibody testing,Biomedical imaging,HEp-2 cells,laws texture measure,indirect immuno?uorescence test
更新于2025-09-19 17:13:59
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Radiology, Lasers, Nanoparticles and Prosthetics || 6. Scintigraphy
摘要： In x-ray radiography and tomography the source of radiation (x-ray tube) is outside the body. Contrast on x-ray films or flat panel detectors is achieved by attenuation of the penetrating radiation in tissues of different density and thickness. In scintigraphy the source of radiation is inside the body. It is administered to the body by injecting radioactive isotopes into the blood circulation. The radioactive isotopes emit γ-radiation, which again is detected by x-ray films or by scintillation detectors. The difference between these two imaging modalities is highlighted in Fig. 6.1. Scintigraphy is not as general an imaging technique as x-ray radiography, the latter being used for inspection of healthy and diseased body parts alike. In contrast, scintigraphy is used for a number of specialized tests. Those include scans for tumor recognition, investigations of the metabolism of bones, of thyroid disorders, kidney clearance, lung ventilation, and of cardiac stress tests. These different scintigraphic applications will be presented in the following.
关键词： nuclear imaging,scintigraphy,radioisotopes,metabolism,γ-radiation
更新于2025-09-19 17:13:59
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in a circularly polarized laser pulse
摘要： The dissociation of H2 + in a circularly polarized laser pulse is numerically studied by simulating the time-dependent Schr?dinger equation. After absorbing one or three photons, the nuclear wave packets carrying the angular momenta ˉh and 3 ˉh dissociate along the 2pσu state. Due to the broad initial kinetic-energy distribution of the superimposed nuclear vibrational states, the one-photon and three-photon dissociation pathways may end with the same kinetic energy. These coexisting dissociation pathways with same parities but different orbital angular momenta interfere with each other, resulting in the spiral nuclear momentum distribution in the laser polarization plane. The interference structure in the nuclear momentum distribution offers another freedom to identify the dissociation pathways of molecules in strong laser fields.
关键词： time-dependent Schr?dinger equation,photon dissociation pathways,circularly polarized laser pulse,spiral nuclear momentum distribution,H2 + dissociation
更新于2025-09-19 17:13:59
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Experimental investigation on nuclear reactions using a laser-accelerated proton and deuteron beam
摘要： We report an experimental investigation on nuclear reactions using an intense, ultra-short laser-accelerated proton and deuteron beam generated by the interaction of 25 fs, 150 TW Ti: sapphire laser pulse with normal thin foils and foils containing deuterium atoms. The production of a positron-emitting short-lived 11C radio-isotope from the interaction of protons and deuterium ions with a solid boron palette by means of 11B (p, n)11C and 10B (d, n)11C nuclear reactions was studied. The maximum radioactivity in the optimized laser irradiation condition was found to be 5.2 kBq per laser shot, which corresponds to ～9 × 106 atoms of 11C isotopes using the 11B (p, n)11C reaction. The relative ef?ciency of 11C production using a proton and deuteron beam was also explored experimentally. About 30 % enhancement in 11C activity was observed with CD2 coated targets. It was also found that because of the relatively low deuteron energy threshold of the reaction 10B (d, n)11C, even the low energy part of the accelerated deuterons in the spectrum can be used for ef?cient 11C production. In the same setup, the proton-induced fusion reaction in the boron target (p + 5B11 ? 3α + 8.7 MeV) was also studied. The resultant fusion yield and alpha particle energy spectrum was measured.
关键词： p?11B fusion,laser particle acceleration,positron emission tomography (PET) isotopes,laser driven ion acceleration,laser plasma interaction,laser induced nuclear reactions,high intensity lasers
更新于2025-09-19 17:13:59
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Surface behavior of 16Cr3Al ODS steel—Effects of high laser intensity 1014 W/cm2 in ambiences of air, helium and vacuum
摘要： The behavior of 16Cr3Al ODS steel (oxide dispersion strengthened steel), widely employed structural fusion material, under high-intensity laser radiation with intensity up to 1014 W/cm2 was investigated in air, helium and vacuum surrounding. Employed system was 65 fs laser at 804 nm, with applied pulse energy up to 5.25 mJ. Morphological effects were studied – cracking, crater parameters (depth, cross-section), LIPSS (laser-induced periodic surface structures) formation at the crater periphery, hydrodynamic effects, as well as chemical variations on the surface. Ablation thresholds were also determined for all three ambiences (for 100 applied pulses), and they were 0.30 J/cm2, 0.23 J/cm2 and 0.39 J/cm2 in air, helium and vacuum, respectively. Plasma occurred in all experiments and it was most prominent in vacuum due to strongest laser-material coupling.
关键词： 1014 W/cm2 laser intensity,Laser-induced damages/craters,Nuclear material,Femtosecond laser surface modification,ODS steel
更新于2025-09-19 17:13:59
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Enhancing frustrated double ionization with no electronic correlation in triatomic molecules using counter-rotating two-color circular laser fields
摘要： We demonstrate a significant enhancement of frustrated double ionization (FDI) in the two-electron triatomic molecule D3+ when driven by counter-rotating two-color circular (CRTC) laser fields. We employ a three-dimensional semiclassical model that fully accounts for electron and nuclear motion in strong fields. For different pairs of wavelengths, we compute the probabilities of the FDI pathways as a function of the ratio of the two field strengths. We identify a pathway of frustrated double ionization that is not present in strongly driven molecules with linear fields. In this pathway the first ionization step is “frustrated” and electronic correlation is essentially absent. This pathway is responsible for enhancing frustrated double ionization with CRTC fields. We also employ a simple model that predicts many of the main features of the probabilities of the FDI pathways as a function of the ratio of the two field strengths.
关键词： counter-rotating two-color circular laser fields,frustrated double ionization,electron and nuclear motion,semiclassical model,triatomic molecules
更新于2025-09-19 17:13:59
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Rate for laser-induced nuclear dipole absorption
摘要： Using the Brink-Axel hypothesis we derive the rate R for nuclear dipole excitation by a laser pulse carrying N (cid:2) 1 photons with average energy ˉhω0 ≈ 5 MeV. As expected R ∝ ( ˉhω0)3. The rate is also proportional to the aperture α of the laser pulse. Perhaps less expected is the fact that R ∝ N, irrespective of the degree of coherence of the laser pulse. The expression for R, derived for a nearly stationary laser pulse, is valid also for short times and can, thus, be used in simulations via rate equations of multiple nuclear dipole excitations by a single pulse. The explicit dependence of R on the parameters of the laser pulse and on nuclear parameters given in the paper should help to optimize experiments on laser-nucleus reactions.
关键词： laser pulse,Giant Dipole Resonance,nuclear dipole excitation,Brink-Axel hypothesis,rate equations
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - The Effects of Axial Stress on CIGS Solar Cell Performance
摘要： At the request of the Domestic Nuclear Detection Office (DNDO), a Study Committee comprised of representatives from the American Physical Society, Panel on Public Affairs, the IEEE, and Nuclear and Plasma Sciences Society performed a technical review of the DNDO Transformational and Applied Research Directorate (TARD) R&D program. TARD’s principal objective is to address gaps in the Global Nuclear Detection Architecture (GNDA) through improvements in the performance, cost, and operational burden of detectors and systems. The charge to the Study Committee was to investigate the existing TARD R&D plan and portfolio, recommend changes to the existing plan, and recommend possible new R&D areas and opportunities. This report is the result of an independent, detailed analysis of the current R&D plan and includes, for each application area, observations, and recommendations to focus future investments within the context of the TARD mission.
关键词： radiation detection,Algorithms and modeling,nuclear forensics,shielded nuclear materials
更新于2025-09-16 10:30:52