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High-temperature mid-infrared absorption spectra of methanol (CH3OH) and ethanol (C2H5OH) between 930 and 1170?cm-1
摘要： A methodology was recently developed with a broad-tuning, rapid-scan external-cavity quantum-cascade-laser in conjunction with shock tube facilities to measure the high-temperature mid-infrared absorption spectra of gaseous molecules. This technique is deployed to measure the cross section profiles in the C-O stretching band for methanol (CH3OH) and ethanol (C2H5OH) between 930 and 1170 cm-1. Methanol spectra are presented from 620 to 1304K between 0.98-3.30 atm with distinctive P, Q, and R branches of the ν8 vibrational band. At elevated temperatures, the emergence of hotbands and high-J ro-vibrational transitions are clearly observed. The absorption cross sections of ethanol are measured from 296 to 1018K between 0.90-3.27 atm. The peak strength decreases with temperature, with the peak location shifting to lower wavenumbers. These measurements are compared with existing empirical models, illustrating a strong need for the development of a high-temperature spectroscopic database.
关键词： Absorption spectra,Ethanol,Mid-infrared,High-temperature,Shock tube,Methanol
更新于2025-09-23 15:23:52
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Singular spectrum analysis filtering and Fourier inversion: an efficient and fast way to improve resolution and quality of current density maps with low-cost Hall scanning systems
摘要： We provide a Biot–Savart inversion scheme that, for any two-dimensional, or bulk with planar crystallization, high-temperature superconducting (HTS) sample, determines current density maps with a higher resolution and accuracy than previous procedures and at a fraction of its computational cost. The starting point of our scheme is a Hall scanning microscopy map of the out-of-plane component of the magnetic field generated by the current. Such maps are noisy in scans of real samples with commercial-grade equipment, and their error is the limiting factor in any Biot–Savart inversion scheme. The main innovation of our proposed scheme is a singular spectrum analysis (SSA) filtering of the Hall probe maps, which cancels measurement errors such as noise or drifts without introducing any artifacts in the field map. The SSA filtering of the Hall probe data is so successful in this task that the resulting magnetic field map does not require an overdetermined QR inversion, allowing Fourier inversion of the Biot–Savart problem. Our implementation of SSA filtering of the Hall scan measurements, followed by Biot–Savart inversion using the fast Fourier transform (FFT), is applied to both simulations and real samples of HTS tape stacks. The algorithm works in cases where ill conditioning ruled out the application of Fourier inversion, and achieves a finer resolution for a fraction of the cost of the QR inversion used to date. The computation passes physical and statistical validity tests in all cases, and in three-dimensional samples it is shown to yield the average, with a depth-dependent weight, of the current density circulating in the different layers of the sample.
关键词： Hall magnetometry,SSA filtering,fast Fourier transform,high-temperature superconducting tapes,Biot–Savart inversion
更新于2025-09-23 15:23:52
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High-<formula><tex>$T_\rm{c}$</tex></formula> Superconducting Fourth-Harmonic Mixer using a Dual-Band Terahertz On-Chip Antenna of High Coupling Efficiency
摘要： This paper presents a dual-band on-chip antenna coupled high-Tc superconducting (HTS) Josephson-junction sub-terahertz (THz) fourth-harmonic mixer. The antenna utilizes a couple of different structured twin-slots to enable the resonant radiations at two frequencies, and integrates a well-designed coplanar waveguide (CPW) network for achieving good radiation coupling and signal isolation characteristics. The electromagnetic (EM) simulations show that coupling efficiencies as high as -4 dB and -3.5 dB are achieved for the 160-GHz and 640-GHz operating frequency bands, respectively. Based on this dual-band antenna, a 640-GHz HTS fourth-harmonic mixer is developed and characterized in a range of operating temperatures. The mixer exhibits a measured conversion gain of around -18 dB at 20 K and -22 dB at 40 K respectively. The achieved intermediate-frequency (IF) bandwidth is larger than 23 GHz. These are the best results reported for HTS harmonic mixers at comparable sub-THz frequency bands to date.
关键词： high-temperature superconductor Josephson junction,dual-band on-chip antenna,terahertz wireless applications,fourth-harmonic mixing,Terahertz mixer
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE International Reliability Physics Symposium (IRPS) - Burlingame, CA (2018.3.11-2018.3.15)] 2018 IEEE International Reliability Physics Symposium (IRPS) - High-temperature and high-field cycling reliability of PZT films embedded within 130 nm CMOS
摘要： We present a systematic reliability study of PZT polarization retention after exposure to high temperatures and high-field cycling. After a 260 °C Pb-free solder assembly reflow-like exposure, a signal margin of >10 μC/cm2 is achieved at a read voltage of 1 V. Extraction of the Preisach distribution after thermal depolarization and restore exhibits an increase in the positive coercive voltage by 45 % while the negative coercive voltage shows minimal deviation (<7 %). Under accelerated aging via high electric fields (2.4 V), maximum wake-up at 106 cycles followed by fatigue >108 cycles is observed. Asymmetry in coercive voltage is minimized after wakeup and remanent polarization maximized. After fatigue, a signal margin >10 μC/cm2 is maintained for read voltages >0.8 V.
关键词： high-temperature bake,Ferroelectric capacitor,thermal depolarization,cycling,data retention,imprint
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD) - Tianjin, China (2018.4.15-2018.4.18)] 2018 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD) - Experimental Study on the Twist Characteristics of Novel HTS Square Wire with Different Structures
摘要： This paper presents the characteristics of novel high temperature superconducting (HTS) twisted square wires with different structure. First, the HTS tapes of 4 mm width are cut into 1 mm width HTS narrow tapes. Then, different numbers of HTS narrow tapes and narrow tape of copper are stacked to prepare a HTS square wire with three structures of 1 + 5c, 2 + 4c and 4 + 2c. Finally, the HTS square wires of these three structures were twisted, and the critical current characteristics of HTS tapes were tested under different twist pitches. The test results show that the twist pitch of the three structures is about 100 mm. The experimental results show that the preparation of HTS square wire with twisted characteristic better, which has broad application prospects in superconducting power equipment.
关键词： twist pitch,critical current,Novel high temperature superconducting twisted square wires,superconducting filaments
更新于2025-09-23 15:23:52
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[IEEE 2018 Seventh Balkan Conference on Lighting (BalkanLight) - Varna (2018.9.20-2018.9.22)] 2018 Seventh Balkan Conference on Lighting (BalkanLight) - Lighting in High Temperature Industrial Enviroment
摘要： The specifics of LED lighting in high temperature industrial environment is discussed in the paper. When industrial sites with very high ambient temperature (60 or even more degrees Celsius) have to be illuminated with LED luminaires, many features of LED lighting that are usually considered a priory true should be carefully studied. That influences the light flux, efficiency, reliability and price of LED lighting installation
关键词： high temperature lighting
更新于2025-09-23 15:23:52
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GaN Integration Technology, an Ideal Candidate for High-Temperature Applications: A Review
摘要： In many leading industrial applications such as aerospace, military, automotive, and deep-well drilling, extreme temperature environment is the fundamental hindrance to the use of microelectronic devices. Developing an advanced technology with robust electrical and material properties dedicated for high-temperature environments represents a significant progress allowing to control and monitor the harsh environment regions. It may avoid using cooling structures while improving the reliability of the whole electronic systems. As a wide bandgap semiconductor, gallium nitride is considered as an ideal candidate for such environments, as well as in high-power and high-frequency applications. We review in this paper the main reasons that offer superiority to GaN devices over better-known technologies such as silicon (Si), silicon-on-insulator, gallium arsenide (GaAs), silicon germanium (SiGe), and silicon carbide (SiC). The theory of operation and main challenges at high temperature are discussed, notably those related to materials and contacts. In addition, the main limitations of GaN, including the technological (thermal and chemical) and intrinsic (current collapse and device self-heating) features are provided. In addition, the GaN devices recently developed for high-temperature applications are examined.
关键词： wide-bandgap semiconductors,high-temperature electronics,Extreme temperature applications,gallium-nitride technology
更新于2025-09-23 15:22:29
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Compact integrated magnetometer based on nitrogen-vacancy centres in diamond
摘要： We demonstrate an integrated and miniaturised magnetic field sensor based on the negatively charged nitrogen-vacancy centres (NV-) in diamond. The compact device includes all optical components, both for the optical excitation path and for the detection of the emitted fluorescence signal. We experimentally verify that it enables optically detected magnetic resonance (ODMR) measurements and we specify noise and sensitivity of the magnetometer. The minimal detectable magnetic field of the device is ≈ 1 μT for a given integration time of 1 ms, which is approximately one order of magnitude larger than its photon shot-noise limit. It has the significant advantage over traditional setups using NV- centres (including a laser and a complex optical system) that the specific construction volume is about 2.9 cm3 with a total power consumption of ≈ 1.5 W, which enables the device for a wide range of industrial sensing applications.
关键词： synthetic diamond,defects,optical properties,high pressure high temperature (HPHT),sensors
更新于2025-09-23 15:22:29
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Ultraviolet electroluminescence from nanostructural SnO2-based heterojunction with high-pressure synthesized Li-doped ZnO as a hole source
摘要： We report an ultraviolet (UV) electroluminescence (EL) in n-SnO2/p-ZnO heterojunction light-emitting diodes with the nanostructural SnO2 as an n-type layer and the Li-doped ZnO (ZnO:Li) synthesized by high-temperature high-pressure (HTHP) method as a high hole concentration p-type layer. Two kinds of SnO2 nanostructures including nanobelts (NBs) and nanowires (NWs) were used to fabricate n-type layers in the heterojunctions. The two heterojunctions with different SnO2 nanostructures demonstrate different light-emission feature in EL measurements. The SnO2 NBs/p-ZnO heterojunction shows a blue emission band centered at 416 nm under forward-bias voltage. A strong UV emission peak located at 391 nm was observed for the SnO2 NWs/p-ZnO heterojunction. Photoluminescence (PL) spectra indicate that the difference in EL is attributed to morphology-dependent light-emission feature in nanostructural SnO2 layer. Our results suggest that the nanostructural SnO2/ZnO:Li heterojunction is a potential and promising system in the UV optoelectronic field.
关键词： High-temperature high-pressure method,Light-emitting diode,Nanobelt,Nanowire,SnO2,Li-doped ZnO
更新于2025-09-23 15:22:29
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Improvement of Conversion Loss of Resistive Mixers Using Bernal-stacked Bilayer Graphene
摘要： In this letter, we present dual-gate Bernal-stacked bilayer graphene FETs which are used for gate-pumped resistive mixers. The results show that conversion loss improves when the device on/off ratio increases. At 2 GHz, a record conversion loss of 12.7 dB has been obtained from 160 nm device among graphene resistive mixers. Furthermore, more than 10 dB change of conversion loss has been obtained by adjusting the electric displacement field by dual-gate voltage. Finally, high-temperature characteristics of this type of graphene mixer exhibit excellent thermal stability with only 2 dB degradation in conversion loss from 300 to 380 K. This result shows the Bernal-stacked bilayer graphene mixer is promising for low-loss and high-temperature radio frequency circuit applications.
关键词： conversion loss,high temperature,bilayer graphene,resistive mixer,FETs
更新于2025-09-23 15:22:29