- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Topological edge state laser using a photonic crystal nanocavity array
摘要： In next-generation light sources, high-brightness electron beams are used in a free-electron laser configuration to produce light for use by scientists and engineers in numerous fields of research. High-brightness beams are described for such light sources as having low transverse and longitudinal emittances, high peak currents, and low slice emittance and energy spread. The optimal generation and preservation of such high-brightness electron beams during the acceleration process and propagation to and through the photon-producing element is imperative to the quality and performance of the light source. To understand the electron beam’s phase space in the accelerating section of a next-generation light source machine, we employed radio-frequency cavities operating in a deflecting mode in conjunction with a magnetic spectrometer and imaging system for both low (250 MeV) and high (1.2 GeV) electron energies. This high-resolution, high-energy system is an essential diagnostic for the optimization and control of the electron beam in the FERMI light source generating fully transversely and longitudinally coherent light in the VUV to soft x-ray wavelength regimes. This device is located at the end of the linear accelerator in order to provide the longitudinal phase space nearest to the entrance of the photon-producing beam-lines. Here, we describe the design, fabrication, characterization, commissioning, and operational implementation of this transverse deflecting cavity structure diagnostic system for the high-energy (1.2 GeV) regime.
关键词： electron beam deflection,free-electron lasers,particle beam measurements,Electron accelerators
更新于2025-09-19 17:13:59
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Determination of atomic oxygen state densities in a double inductively coupled plasma using optical emission and absorption spectroscopy and probe measurements
摘要： A collisional radiative model for fast estimation and monitoring of atomic oxygen ground and excited state densities and ?uxes in varying Ar:O2 mixtures is developed and applied in double inductively coupled plasma source at a pressure of 5 Pa and incident power of 500 W. The model takes into account measured line intensities of 130.4 nm, 135.6 nm, 557.7 nm, and 777.5 nm, the electron densities and electron energy distribution functions determined using a Langmuir probe and multipole resonance probe as well as the state densities of the ?rst four excited states of argon measured with the branching fraction method and compared to tunable diode laser absorption spectroscopy. The in?uence of cascading and self absorption is included and the validity of the used cross sections and reaction rates is discussed in detail. The determined atomic oxygen state densities are discussed for their plausibility, sources of error, and compared to other measurements. Furthermore, the results of the model are analyzed to identify the application regimes of much simpler models, which could be used more easily for process control, e.g. actinometry.
关键词： absorption spectroscopy,atomic oxygen,probe measurements,collisional radiative model,optical emission spectroscopy
更新于2025-09-19 17:13:59
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[IEEE 2019 International Conference on Image and Vision Computing New Zealand (IVCNZ) - Dunedin, New Zealand (2019.12.2-2019.12.4)] 2019 International Conference on Image and Vision Computing New Zealand (IVCNZ) - Accurate 3D Measurement of Highly Specular Surface using Laser and Stereo Reconstruction
摘要： In the production line, Inspection and Quality Control are essential to maintain the quality of the products. Same as the manufacturing process, the process of quality checking should also be automatic [1]. In addition to automation in quality checking, the process needs to be simple, fast, accurate and cost-effective. ”Machine vision is the technology and methods used to provide imaging-based automatic inspection and analysis [2].” However, Re?ective Surface of the object puts some limitations on traditional methods of machine vision. This research paper focuses on the development of a simple and accurate 3D measuring system for the inspection of re?ective surface objects. The idea is to combine the concepts of stereo vision and sheet of light techniques. The main advantage of this method is that it overcomes the limitations of traditional methods and works robustly in ambient lighting condition. In this paper, we described a number of experiments carried out on different shapes and sizes of re?ective surface objects using the proposed method. The qualitative and quantitative reconstructed 3D pro?les of different shapes of re?ective surface objects are shown. In the end, the results are compared with the ground truth three-dimensional model of the acquited objects for accuracy evaluation.
关键词： Inspection,Re?ective Surface,Laser Line Projection,3D Measurements,Stereo Vision
更新于2025-09-19 17:13:59
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Photovoltaic activity of electrodes based on intact photosystem I electrodeposited on bare conducting glass
摘要： We demonstrate photovoltaic activity of electrodes composed of fluorine-doped tin oxide (FTO) conducting glass and a multilayer of trimeric photosystem I (PSI) from cyanobacterium Synechocystis sp. PCC 6803 yielding, at open circuit potential (OCP) of + 100 mV (vs. SHE), internal quantum efficiency of (0.37 ± 0.11)% and photocurrent density of up to (0.5 ± 0.1) μA/cm2. The photocurrent measured for OCP is of cathodic nature meaning that preferentially the electrons are injected from the conducting layer of the FTO glass to the photooxidized PSI primary electron donor, P700+, and further transferred from the photoreduced final electron acceptor of PSI, Fb, via ascorbate electrolyte to the counter electrode. This observation is consistent with preferential donor-side orientation of PSI on FTO imposed by applied electrodeposition. However, by applying high-positive bias (+ 620 mV) to the PSI-FTO electrode, exceeding redox midpoint potential of P700 (+ 450 mV), the photocurrent reverses its orientation and becomes anodic. This is explained by “switching off” the natural photoactivity of PSI particles (by the electrochemical oxidation of P700 to P700+) and “switching on” the anodic photocurrent from PSI antenna Chls prone to photooxidation at high potentials. The efficient control of the P700 redox state (P700 or P700+) by external bias applied to the PSI-FTO electrodes was evidenced by ultrafast transient absorption spectroscopy. The advantage of the presented system is its structural simplicity together with in situ-proven high intactness of the PSI particles.
关键词： Photoelectrochemical measurements,Cyanobacterium Synechocystis sp. PCC 6803,Femtosecond-transient absorption,Photovoltaics,FTO conducting glass,Photosystem I
更新于2025-09-19 17:13:59
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Potential energy shift of the Fermi level at plasmonic structures for light-energy conversion determined by graphene-based Raman measurements
摘要： Single layer graphene was used to determine the electrochemical potential of plasmonic nano-structures for photoelectrochemical energy conversions. From electrochemical Raman measurements of the graphene layer under near-infrared light, illumination has revealed the relationship between the photoenergy conversion ability and the Fermi level of the plasmonic structure. The determination is based on in situ monitoring of G and 2D Raman bands of the graphene layer on plasmonic structures. The correlation plots of G and 2D bands show the dependence on the photoconversion ability. The present electrochemical Raman measurements provide detailed understanding of the plasmon-induced charge transfer process for further developments on the ability.
关键词： plasmonic structures,Raman measurements,graphene,Fermi level,photoelectrochemical energy conversion
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 5th International Conference on Wireless and Telematics (ICWT) - Yogyakarta, Indonesia (2019.7.25-2019.7.26)] 2019 IEEE 5th International Conference on Wireless and Telematics (ICWT) - The Behavioral Study of an Optical Injection-Locked Semiconductor Laser under the Influence of Intensity and Phase Noise
摘要： Channel electron multiplier (CEM) and microchannel plate (MCP) detectors are routinely used in space instrumentation for measurement of space plasmas. Our goal is to understand the relative sensitivities of these detectors to penetrating radiation in space, which can generate background counts and shorten detector lifetime. We use keV -rays as a proxy for penetrating radiation such as -rays, cosmic rays, and high-energy electrons and protons that are ubiquitous in the space environment. We find that MCP detectors are times more sensitive to keV -rays than CEM detectors. This is attributed to the larger total area of multiplication channels in an MCP detector that is sensitive to electronic excitation and ionization resulting from the interaction of penetrating radiation with the detector material. In contrast to the CEM detector, whose quantum efficiency keV -rays is found to be 0.00175 and largely independent of detector bias, the quantum efficiency of the MCP detector is strongly dependent on the detector bias, with a power law index of 5.5. Background counts in MCP detectors from penetrating radiation can be reduced using MCP geometries with higher pitch and smaller channel diameter.
关键词： gamma-ray effects,radiation effects,plasma measurements,Electron multipliers
更新于2025-09-19 17:13:59
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[IEEE 2019 21st International Conference on Transparent Optical Networks (ICTON) - Angers, France (2019.7.9-2019.7.13)] 2019 21st International Conference on Transparent Optical Networks (ICTON) - Plasmonic Waveguides Co-Integrated with Si <sub/>3</sub> N <sub/>4</sub> Waveguide Platform for Integrated Biosensors
摘要： This paper presents a placement algorithm for fault location observability using phasor measurement units (PMUs) in the presence or absence of zero injection buses. The problem is formulated as a binary semidefinite programming (BSDP) model with binary decision variables, minimizing a linear objective function subject to linear matrix inequality (LMI) observability constraints. The model is extended to take into account the unavailability or limited capacity of communication links at some PMU installation buses. The BSDP problem is solved using an outer approximation scheme based on binary integer linear programming. The method is illustrated with a 6-bus test system. Numerical simulations are conducted on the IEEE 14-, 30-, and 57-bus standard test systems to verify the effectiveness of the proposed method.
关键词： semidefinite programming,phasor measurement unit,linear matrix inequality,Fault location observability,synchronized phasor measurements
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Influence of Measurements Uncertainty on Uncertainty of Gilbert-Huang Transform Modes
摘要： The approach to simplifying the identification of a system using the input and output non-stationary or stationary processes is proposed in the article. The realizations of the process (input and output signals) are converted to the sum of individual components (modes) based on the Hilbert-Huang transform, and then the corresponding modes of this transformation are used for the virtual subsystem identification. The identification quality depends on the measurement uncertainty of both the signal and its Hilbert-Huang modes. The influence of measurements uncertainty of the signal on the individual modes’ uncertainty, considering important factors, is analyzed in the article. The obtained results extend the conditions for solving the problems of system identification.
关键词： measurements uncertainty,system identification,Hilbert-Huang transform
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE/CVF International Conference on Computer Vision (ICCV) - Seoul, Korea (South) (2019.10.27-2019.11.2)] 2019 IEEE/CVF International Conference on Computer Vision (ICCV) - A Neural Network for Detailed Human Depth Estimation From a Single Image
摘要： Disordered ionic-bonded transition metal oxide thin-film transistors (TFTs) show promise for a variety of dc and RF switching applications, especially those that can leverage their low-temperature, substrate-agnostic process integration potential. In this paper, enhancement-mode zinc-oxide TFTs were fabricated and their switching performance evaluated. These TFTs exhibit the drain-current density of 0.6 A/mm and minimal frequency dispersion, as evidenced by dynamic current–voltage tests. A high-frequency power switch figure of merit RON QG of 359 mΩ · nC was experimentally determined for 0.75-μm long-channel devices, and through scaling 45.9 mΩ · nC is achievable for 11 V-rated devices (where RON is ON-state drain–source resistance, and QG is gate charge). An RF switch cutoff frequency fc of 25 GHz was measured for the same 0.75-μm TFT, whereas fc exceeding 500 GHz and power handling in the tens of watts are projected with optimization.
关键词： monolithic ICs,pulse measurements,zinc oxide,gate charge,dc switch,ionic semiconductors,RF switch,thin-film transistors (TFTs),Cutoff frequency
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE International Conference on Space Optical Systems and Applications (ICSOS) - Portland, OR, USA (2019.10.14-2019.10.16)] 2019 IEEE International Conference on Space Optical Systems and Applications (ICSOS) - High Power Indium Phosphide Photonic Integrated Circuit for Pulse Position Modulation Free Space Optical Communications
摘要： Detection of defects in induction machine rotor bars for disassembled motors are required to evaluate machines considered for repair as well as fulfilling incremental quality assurance checks in the manufacture of new machines. Detection of rotor bar defects prior to motor assembly are critical in increasing repair efficiency and assuring the quality of newly manufactured machines. Many methods of detecting rotor bar defects in unassembled motors lack the sensitivity to find both major and minor defects in both cast and fabricated rotors along with additional deficiencies in quantifiable test results and arc-flash safety hazards. A process of direct magnetic field analysis can examine measurements from induced currents in a rotor separated from its stator yielding a high-resolution fingerprint of a rotor’s magnetic field. This process identifies both major and minor rotor bar defects in a repeatable and quantifiable manner appropriate for numerical evaluation without arc-flash safety hazards.
关键词： magnetic flux,ac motors,electromagnetic measurements,induction motors,rotors,AC machines
更新于2025-09-19 17:13:59