- 标题
- 摘要
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- 实验方案
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AN ALGORITHM TO DETERMINE THE NANODOSIMETRIC IMPACT OF GOLD NANOPARTICLES ON CELL MODELS
摘要： High-Z nanomaterials, e.g. gold nanoparticles (GNPs), are being investigated worldwide for potential application in radiation imaging and therapy. Photon irradiation of cells containing GNP was shown to produce enhanced DNA damage which is believed to be related to the increased secondary electron (SE) yield and ionization density. In this work, an algorithm was developed for simulating the physical radiation damage inside the nucleus of a spherical cell model for the case of uniformly distributed GNPs within the cytoplasm. Previously calculated energy spectra of SE emerging from a single NP irradiated with different photon sources are used as input to obtain the SE energy spectrum at the surface of the cell nucleus. In a second step, the SE transport inside the cell nucleus is simulated with a track structure Monte Carlo code to obtain the spatial distribution of ionizations. The preliminary results presented here show that the developed algorithm allows for a fast calculation of the SE spectra at the cell nucleus surface, thus enabling a more realistic assessment of the ionization density inside the cell nucleus than that obtained by the simulation of a single GNP. Furthermore, the algorithm can be easily adapted to investigate both the effect of GNP clustering and the impact of GNP–GNP interactions on SE spectra.
关键词： radiation therapy,secondary electrons,gold nanoparticles,Monte Carlo simulation,ionization density
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 7th Global Conference on Consumer Electronics (GCCE) - Nara, Japan (2018.10.9-2018.10.12)] 2018 IEEE 7th Global Conference on Consumer Electronics (GCCE) - Analysis of Unintentional Signal Propagation in Intra-Body Communication
摘要： This paper describes an analysis of unintentional signal propagation in intra-body communication (IBC). IBC might suffer from such unintentional signal, which are caused by both a return path and a normal path. We propose an unintentional signal propagation model based on both of these paths. In this work, we analyze the unintentional signal through experiments and simulations. The signal strength characteristics, as found from the simulation results, were similar to those of the experimental results. Our model is, therefore, confirmed to be adequate. The unintentional signal through the return path is found to be greater than that of the normal path. The design criteria for IBC application are also indicated that may address the unintentional signal problem.
关键词： normal path,intra-body communication,return path,electromagnetic field simulation,unintentional signal
更新于2025-09-04 15:30:14
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[Lecture Notes in Electrical Engineering] Recent Trends in Communication, Computing, and Electronics Volume 524 (Select Proceedings of IC3E 2018) || Magnetic Field Sensitivity in Depressed Collector for a Millimeter-Wave Gyrotron
摘要： The electron beam trajectories were simulated in a single-stage depressed collector for a millimeter-wave gyrotron. This collector was designed to handle the spent beam obtained after beam-wave interaction in the 100 kW gyrotron (accelerating voltage 55 kV and beam current 5 A). Similar to other high-power gyrotrons, this collector has larger volume considered at ground potential. The cathode and the beam-wave interaction cavity were considered at ?40 kV and +15 kV, respectively. The collector sees the depression of 15 kV. The geometry of the collector is considered as three sections: (i) the open entrance conical section, (ii) the smooth cylindrical section, and (iii) the closed conical section. In order to simulate the beam trajectory from nonlinear taper to collector, the electron trajectories and spent beam power distribution data obtained from large-signal analysis have been fed at the entrance of mode converter of the gyrotron with required potentials applied. The collector geometry and the magnetic ?eld are pro?led to ensure the landing of the gyrating electrons to the wider smooth cylindrical section for better thermal management. The sensitivity of the magnetic ?eld pro?le is studied and observed that for ±5% variation in the magnetic ?eld pro?le would not shift the electron beam landing to conical sections, and the spent electron beam has no interception. The power dissipation on the collector is found to be 80.55 kW. The collector ef?ciency is calculated as ~48% for 120 kW RF output. The maximum thermal loading on collector inner surface is estimated as 0.38 kW/cm2.
关键词： Millimeter-wave gyrotron,Electron trajectory simulation,W-band gyrotron,Depressed collector
更新于2025-09-04 15:30:14
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Analysis of Phase Noise and Transmit/Receive Isolation Influence on FMCW-Radar Performance
摘要： The detection sensitivity of frequency modulated continuous-wave (FMCW) radar is limited by the phase noise performance of LO signal and the transmitter to receiver leakage. The influence of phase noise and transmit/receive isolation in target detection has been investigated in this paper. The developed system-level simulation model for FMCW radar with defined noisy oscillator has been built up to analysis the impact of phase noise and isolation. The analysis and simulation indicates that the noise skirt of large echo signal and leakage signal increase the noise floor to affect small target signal detection, and the relations between noise floor deterioration and distance, phase noise, isolation are obtained from the model simulation results, which provide useful design constrains for FMCW radar system.
关键词： transmit/receive isolation,system-level simulation,phase noise,noise floor,FMCW radar
更新于2025-09-04 15:30:14
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Reliability of High-Power Mechatronic Systems 1 || Simulation of Degradation Phenomena in Semiconductor Components in order to Ensure the Reliability of Integrated Circuits
摘要： The design cycle until now only guaranteed the electrical performance of integrated circuits (ICs) before aging. Performances throughout product lifetimes are, in general, assured by taking design margins and accelerated aging tests that come in a second complementary phase to guarantee the circuit reliability. In case of degradation, a reactive design correction will necessarily mean a delay in placing the product on the market. The design cycle subject to delay has not yet passed control. This study proposes guaranteeing the level of reliability of an integrated circuit during the design phase. This new design methodology requires a simulation tool for the aging of components. In this phase of the study, reliability tests on manufactured circuits will consolidate the results of reliability simulation up to the point of refining these individualized models by component. Once the components of a technology are properly modeled, the number of reliability incidents must tend towards 0. Marketing is advanced and the design cycle is gaining control. This makes it possible to hope that this technology will be available on the market as soon as the first silicon is available, without having to wait for any accelerated qualification tests. The circuits are guaranteed to be conceptually reliable.
关键词： simulation,design methodology,reliability,integrated circuits,aging
更新于2025-09-04 15:30:14
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Multiphysics THz Antenna Simulations
摘要： The electrical response of an antenna-coupled nanothermocouple depends on how well the antenna converts incident optical energy to heat, and how this heat is converted to electrical signals by the nanothermocouples. In this paper, we study by COMSOL simulations the heat dissipated in dipole antennas operating at 600 GHz to maximize the temperature at the center of the antenna where the nanothermocouples are attached. We study antennas constructed from all-Au, all-Ni, and Au with Ni center segment. We also study the heat loss into the Si substrate, and use various thicknesses of SiO2 for thermal insulation from the substrate. We also discuss our simulation setup and our symmetric, geometry-independent mesh structure to avoid a variety of simulation errors and artifacts.
关键词： Simulation,Nanotechnology,Thermoelectricity,Thermoelectric devices,Antennas
更新于2025-09-04 15:30:14
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[ASME ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems collocated with the ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels - San Francisco, California, USA (Monday 6 July 2015)] Volume 1: Thermal Management - A Study on the Thermo-Fluid Simulation Model Using Porous Media in the Power Conversion System
摘要： When converting an electric power by an insulated-gate bipolar transistor (IGBT) module, the problem which is the heat generation in the IGBT module should be prudently considered in the design process. As an engineer reviews the cooling performance of power semi-conductor devices only at the component level, it is difficult to predict the reduction of airflow rates in the heat sink when power semi-conductor devices including the heat sink are integrated into the power conversion system. As the porous media model is adopted in the IGBT stack of the PCS, the problem that the meshes are heavily concentrated in the IGBT module including the heat sink, air, and IGBT/ diode chips can be evaded and the airflow rate which is reflected in the effect of flow resistance by all interior structures including the IGBT module is calculated. For the outdoor type PCS, the hotspot temperature on the heat sink of the simulation and experiment is 99.3 and 101.6 Celsius, respectively. The proposed numerical simulation model considerably accurately predicts the hotspot temperature on the heat sink and can earn benefits in terms of efforts of mesh generation and computation time.
关键词： porous media model,heat sink,thermo-fluid simulation,power conversion system,IGBT module
更新于2025-09-04 15:30:14
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[IEEE 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Austin, TX, USA (2018.9.24-2018.9.26)] 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Emerging Memory Modeling Challenges (Invited Paper)
摘要： Emerging Memory (EM) is a broad class of memory devices leveraging a wide spectrum of physical phenomena and/or material properties, that go beyond the charge storage concept of more conventional NAND and DRAM technologies. Availability of physical models and simulation tools to understand their behavior, predict performance, engineer materials and cell architecture would be extremely useful for their successful development. However, such tools are not always available because of the diversity and complexity of the physical mechanisms. This paper would like to review the main trends of the on-going modeling and simulation activities in the field of EM, trying to point out what are the needs and challenges for the future.
关键词： Modeling,Phase Change Memory,Simulation,Resistive RAM,Emerging Memory,Spin Transfer Torque Magnetic RAM
更新于2025-09-04 15:30:14
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DukeSim: A realistic, rapid, and scanner-specific simulation framework in computed tomography
摘要： The purpose of this study was to develop a CT simulation platform that is 1) compatible with voxel-based computational phantoms, 2) capable of modeling the geometry and physics of commercial CT scanners, and 3) computationally efficient. Such a simulation platform is designed to enable the virtual evaluation and optimization of CT protocols and parameters for achieving a targeted image quality while reducing radiation dose. Given a voxelized computational phantom and a parameter file describing the desired scanner and protocol, the developed platform DukeSim calculates projection images using a combination of ray-tracing and Monte Carlo techniques. DukeSim includes detailed models for the detector quantum efficiency, quantum and electronic noise, detector crosstalk, subsampling of the detector and focal spot areas, focal spot wobbling, and the bowtie filter. DukeSim was accelerated using GPU computing. The platform was validated using physical and computational versions of a phantom (Mercury phantom). Clinical and simulated CT scans of the phantom were acquired at multiple dose levels using a commercial CT scanner (Somatom Definition Flash; Siemens Healthcare). The real and simulated images were compared in terms of image contrast, noise magnitude, noise texture, and spatial resolution. The relative error between the clinical and simulated images was less than 1.4%, 0.5%, 2.6%, and 3%, for image contrast, noise magnitude, noise texture, and spatial resolution, respectively, demonstrating the high realism of DukeSim. The runtime, dependent on the imaging task and the hardware, was approximately 2-3 minutes per rotation in our study using a computer with 4 GPUs. DukeSim, when combined with realistic human phantoms, provides the necessary toolset with which to perform large-scale and realistic virtual clinical trials in a patient and scanner-specific manner.
关键词： simulation,ray tracing,monte carlo,computational human phantoms,computed tomography,virtual clinical trial,in silico modeling,CT simulator
更新于2025-09-04 15:30:14
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Experimental Measurement and Monte Carlo Simulation the Correction Factor for the Medium-Energy X-ray Free-air Ionization Chamber
摘要： A key comparison has been made between the air-kerma standards of the National Institute of Metrology (NIM), China, and other Asia Pacific Metrology Programme (APMP) members in the medium-energy X-ray. This paper reviews the primary standard Free-air ionization chamber correction factor experimental method and Monte Carlo simulation method in the NIM. The experimental method and the Monte Carlo simulation method are adopted to obtain the correction factor for the medium-energy X-ray primary standard free-air ionization chamber at 100 kV, 135 kV, 180 kV, 250 kV four CCRI reference qualities. The correction factor has already been submitted to the APMP as key comparison data and the results are in good agreement with those obtained in previous studies. This study shows that the experimental method and the EGSnrc simulation method are usually used in the measurement of the correction factor. In particular, the application of the simulation methods is more common.
关键词： Correction factor,Air-kerma,Experimental method,Free-air ionization chamber,Monte Carlo simulation
更新于2025-09-04 15:30:14