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- 实验方案
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Microwave transmission performance of fused silica ceramics in microwave high-temperature heating
摘要： Compared with traditional heating methods, microwave heating is widely used in many industrial heating fields because of its advantages, such as material-selective heating, volumetric heating and high-efficiency heating. However, previous studies have shown that the heating mode depends on the transmission performance of refractory insulation materials. In this study, a commonly used refractory material (fused silica ceramics) for microwave heating was studied, according to the law of electromagnetic wave propagation in a single-layer plate, the power transmission coefficient (PTC) of the material at different thickness, temperature and frequency (915 MHz and 2360 MHz) was calculated and analysed, in order to design the refractory structure which has good microwave transmission performance in the whole microwave heating process. The results show that the transmission performance of fused silica ceramics fluctuates regularly with increasing thickness, and there are several microwave transmission peaks in the PTC patterns, the thicknesses corresponding to the transmission peaks at frequency 2360 MHz are in order 0.033 m, 0.065 m and 0.098 m; as the temperature increases, the position of the transmission peaks will shift to a smaller thickness, the transmission performance of fused silica ceramics decreases slightly with increasing temperature. Comparing the transmission performance of mullite, alumina (Al2O3) and fused silica ceramics, it was found that the fused silica ceramics have excellent transmission properties; especially it is at high temperature. The results of this study can provide guidance for the selection of refractory structure materials and sizes as well as the optimization of heating process parameters in high-temperature microwave heating.
关键词： A. Microwave heating,D. Transmission performance,B. Fused silica ceramic,C. High temperature wave transmitting material
更新于2025-09-23 15:22:29
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Steam piping infrared image segmentation with trend coefficients algorithm
摘要： In the industrial production or life of mankind, the use of steam piping network brings convenience and rapidity. As we all know, steam piping are often applied to transport high-temperature materials. Excessive temperature often has potential safety hazards or causes waste of resources. This requires real-time monitoring of abnormal phenomena such as excessive local temperature in steam pipelines. Based on the characteristics of infrared images, steam network pipe images can be easily captured by infrared thermal imager. However, the complexity and diversity of the environment make it difficult for infrared images to directly distinguish the high temperature area and normal temperature area of the pipes. In order to solve this problem, this paper proposes a trend coefficient algorithm for infrared spectroscopy image. Firstly, one-dimensional single-threshold Otsu method is extended to one-dimensional multi-threshold acquisition, and then one-dimensional method is extended to two-dimensional method to form two-dimensional double-threshold Otsu segmentation algorithm. The algorithm includes the trace of between-class scatter matrix as the evaluation function, and analyzes the trend coefficient to obtain the optimal threshold. Through the simulation experiment of MATLAB, it can be seen that the method can clearly get the distribution of high temperature area of pipeline image. It not only extracts the pipeline area from the image, but also accurately segments and locates the over-temperature area on the steam pipeline image. And it also eliminates the interference of trees and shrubs in the outdoor environment to a certain extent. Under the characteristics of different steam pipeline images, the evaluation results confirm that the proposed method can locate and segment the high temperature area of pipeline accurately.
关键词： Infrared high temperature region,Steam piping infrared image segmentation,Trend coefficients algorithm
更新于2025-09-23 15:22:29
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Growth behavior and thermally stable electrical properties of TiNbO5 nanosheet thin films grown using the electrophoretic method
摘要： TiNbO5 (TNO) thin films were deposited by electrophoresis at room temperature by using TNO nanosheets. These TNO films exhibited a large (001) interplanar distance (1.18 nm) owing to the presence of TBA+ between the TNO layers. The TBA+, which were used to synthesize the TNO nanosheets, were removed from the TNO film after annealing at 600 °C. Two types of structures were developed in the film annealed at 600 °C: type-1 and type-2, which revealed (001) interplanar distances of 0.52 and 0.71 nm, respectively. The TNO film annealed at 600 °C showed a dielectric constant of 48.5, low dielectric loss (0.02), and small leakage current density of 4.16 × 10^-7 A/cm^2 at 0.6 MV/cm. The dielectric properties were stable with respect to the film thickness and the applied electric field; the dielectric and insulation properties were maintained up to 300 °C. Therefore, TNO films are good candidates for high-temperature capacitors.
关键词： Electrophoresis,Robust dielectric,Inorganic nanosheets,TiNbO5 film,High temperature capacitor
更新于2025-09-23 15:22:29
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In-situ 3D shape and recession measurements of ablative materials in an arc-heated wind tunnel by UV stereo-digital image correlation
摘要： In-situ three-dimensional (3D) ablation shape and recession measurements of ablative materials of hypersonic vehicles in high-temperature wind tunnel tests are essential to understand the ablation performance of these materials, which can provide necessary information for better thermal protection system (TPS) design. In this work, a novel ultraviolet stereo-digital image correlation (UV stereo-DIC) technique is proposed for in-situ measurements of 3D ablation shapes and recession in ablation tests. Specifically, a self-developed UV stereo-DIC system, combing a monochromatic UV illumination, two bandpass filters and two UV cameras, is first established. Using the UV stereo-DIC system, strong thermal radiation emitted from the heated sample and the heating device can be effectively suppressed. Natural textures formed from illuminating the rough sample surface by UV light are used as speckle patterns in stereo-correlation. In-situ 3D ablation shapes of a blunt cone subjected to arc heating were measured with a temperature range of 1000 °C to 1868 °C, and the UV stereo-DIC measurements showed good agreement with post-test measurement of the recession of the test articles. Based on the experimentally measured 3D shapes, several key parameters, such as full-field recession, dynamic recession rate, were calculated. The results demonstrate the efficacy and potential of UV stereo-DIC for 3D shape and recession measurements in ablation tests.
关键词： Recession,High temperature,UV stereo-digital image correlation,Ablation shape
更新于2025-09-23 15:22:29
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Spatial heterodyne spectroscopy for high speed measurements of Stark split neutral beam emission in a high temperature plasma
摘要： Measurement of electrostatic potential, or local electric field, turbulence is a critical missing component in validating nonlinear turbulence and transport simulations of fusion plasmas. A novel diagnostic is being developed for measuring local electric field fluctuations, ?E(r, t), via high-speed measurements of the light emitted from a hydrogenic neutral beam. It exploits the proportionality of the spectral line splitting from the Motional Stark Effect to the total electric field experienced by the neutral atom at the excitation site. The measurement is localized by the usual cross-beam geometry of beam-spectroscopy measurements. The corner stone of the diagnostic is a high spectral resolution, high etendue spatial heterodyne spectrometer (SHS). A SHS design with high etendue (～5 mm2 sr) and resolution (～0.14 nm) meets the formidable spectrometer requirements. Field tests of the spectrometer at the DIII-D tokamak demonstrate that the beam emission spectrum produced by the SHS agrees with that of a traditional spectrometer and that the measured flux is adequate for turbulence studies.
关键词： Stark split neutral beam emission,electric field fluctuations,spatial heterodyne spectroscopy,turbulence diagnostics,high temperature plasma
更新于2025-09-23 15:21:21
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[IEEE 2018 41st International Spring Seminar on Electronics Technology (ISSE) - Zlatibor, Serbia (2018.5.16-2018.5.20)] 2018 41st International Spring Seminar on Electronics Technology (ISSE) - Solid-Liquid Interdiffusion Bonding Based on Au-Sn Intermetallic for High Temperature Applications
摘要： This paper covers one of the aspects of solid-liquid interdiffusion (SLID) bonding of semiconductor structures to substrate for high temperature operation. Investigations were focused on Au/Sn intermetallic compounds formed at the interface between Au metallization on the chip and Sn metallization on the DBC (Direct Bonded Copper) substrate. Two version of SLID were applied: one stage process at 350?°C and two stage process short time at 280?°C + long time at 180?°C. Second process is divided into two steps: short high temperature (280?°C) step for melting Sn and initial intermetallic compound formation and long low temperature (180?°C) step for solid state diffusion process. Design of experiments technique was used for process optimization. The best process parameters were obtained and they were applied for monocrystalline GaN chips assembly to DBC substrates. In the long-term stability tests at 300?°C it was proven that both versions of investigated SLID technique can be applied for monocrystalline GaN chips assembly. Critical condition for this assembly operation is high enough pressure applied on the chip to initiate diffusion process.
关键词： High Temperature Applications,GaN chips,Au-Sn Intermetallic,DBC substrate,Solid-Liquid Interdiffusion Bonding
更新于2025-09-23 15:21:21
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Design and Implementation of Distributed Ultra-High Temperature Sensing System With a Single Crystal Fiber
摘要： Modern high-temperature processes, such as fossil energy production, nuclear reactors, and chemical reactors lack robust, distributed sensing systems to map temperatures in these high-value harsh-environment systems. Regular silica-fiber-based distributed temperature sensing systems usually only operate at temperatures below about 800 °C. In this paper, we present the design, implementation, and testing of a distributed ultra-high temperature sensing system using Raman scattering intensity, which operates from room temperature to above 1400 °C. Consideration is given to the impacts of thermal radiation, fluorescence, and the multimode nature of unclad single-crystal fiber to optimize the system. Results from picosecond and sub-nanosecond lasers were compared. Measurements were taken with a ～2 m sapphire optical fiber, which represents the longest commercially available length. A spatial resolution of 12.4 cm and position standard deviation of 0.28 mm were achieved up to the maximum testing temperature of 1400 °C, which is a new record for distributed temperature sensing systems.
关键词： Raman scattering,optical fiber applications,high-temperature,Crystals,time-domain analysis
更新于2025-09-23 15:21:21
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Self-powered flexible electronics beyond thermal limits
摘要： Self-powered flexible electronics using high-performance inorganic materials have been studied and developed for the essence of future electronics due to the thing, lightweight, self-sustainable, and biocompatible characteristics, which can be applied to body sensor network and next generation Internet of Things (IoT). However, most of inorganic materials should be processed in the high-temperature processes such as the semiconductor fabrication, which is not compatible flexible plastic substrates. Therefore, the new approaches must be demonstrated to overcome the thermal limits of previous methodology and achieve the flexible inorganic electronics on various flexible plastic substrates. In this review paper, we introduce the recent progress of technologies to realize flexible and high-performance inorganic electronics on plastic substrates over the thermal limits, i.e., laser-assisted procedure, chemical or mechanical exfoliation approaches. They are compatible not only to flexible plastic substrates but also to conventional device processes. We also explain the novel application devices such as flexible optoelectronics, flexible large-scale integration (LSI) devices, flexible energy harvesters, and flexible sensors using the recent-developed technologies beyond the previous thermal limit. This paper highlights the proper direction to complete future flexible inorganic electronics for high-performance self-powered systems.
关键词： High-temperature process,Self-powered device,Exfoliation,System-on-plastic,Laser technology,Flexible electronics
更新于2025-09-23 15:21:21
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Noise mitigation methods for ion detectors operating with a direct view of high temperature plasmas
摘要： We have developed an ion current measurement instrument with a direct view of a plasma that reduces the particle and radiation-induced noise current it detects by over three orders of magnitude, from tens of microamps to tens of nanoamps. This is accomplished using electric ?elds, magnetic ?elds, and physical shielding that limit the ?ux of particles and radiation into the instrument and suppress the secondary electrons produced within it by particle and radiation impact. Operation of this detector in various con?gurations, without an ion beam, has allowed identi?cation of the sources of noise current. In our experimental setup, the largest noise contributors were found to be plasma ions and photoelectric emission due to UV radiation.
关键词： high temperature plasmas,magnetic fields,electric fields,ion detectors,physical shielding,noise mitigation
更新于2025-09-23 15:21:21
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Photonic materials for high-temperature applications: Synthesis and characterization by X-ray ptychographic tomography
摘要： Photonic materials for high-temperature applications need to withstand temperatures usually higher than 1000 ?C, whilst keeping their function. When exposed to high temperatures, such nanostructured materials are prone to detrimental morphological changes, however the structure evolution pathway of photonic materials and its correlation with the loss of material’s function is not yet fully understood. Here we use high-resolution ptychographic X-ray computed tomography (PXCT) and scanning electron microscopy (SEM) to investigate the structural changes in mullite inverse opal photonic crystals produced by a very-low-temperature (95 ?C) atomic layer deposition (ALD) super-cycle process. The 3D structural changes caused by the high-temperature exposure were quantified and associated with the distinct structural features of the ceramic photonic crystals. Other than observed in photonic crystals produced via powder colloidal suspensions or sol-gel infiltration, at high temperatures of 1400 ?C we detected a mass transport direction from the nano pores to the shells. We relate these different structure evolution pathways to the presence of hollow vertexes in our ALD-based inverse opal photonic crystals. Although the periodically ordered structure is distorted after sintering, the mullite inverse opal photonic crystal presents a photonic stopgap even after heat treatment at 1400 ?C for 100 h.
关键词： Ptychography X-ray computed tomography,High-temperature applications,3D image analysis,Photonic materials,Low-temperature atomic layer deposition
更新于2025-09-23 15:21:01