修车大队一品楼qm论坛51一品茶楼论坛,栖凤楼品茶全国楼凤app软件 ,栖凤阁全国论坛入口,广州百花丛bhc论坛杭州百花坊妃子阁

oe1(光电查) - 科学论文

过滤筛选

出版时间
  • 2018
研究主题
  • interdigital resonator
  • microwave gas sensor
  • PSE-coated
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • King Mongkut’s University of Technology North Bangkok
  • Rajamangala University of Technology Suvarnabhumi
571 条数据
?? 中文（中国） ▾

  • Study of anharmonicity in pure and doped InSe by Raman scattering

    摘要： With the help of temperature dependence, Raman scattering anharmonic effect of various modes of layered semiconductor InSe over temperature range of 20–650 K has been studied. It was found that with an increase in temperature, anharmonicity will increase. Two and three phonons coupling with optical phonon, are used to describe temperature-induced anharmonicity in the linewidth of Raman modes. It was found that the temperature variation of the phonon parameter can be accounted for well by the cubic term in anharmonic model. To describe line-center shift of Raman modes, a model not considering independently cubic and quartic anharmonicity was used. A similar study has been done for InSe doped with different concentration of GaS dopant. The result of temperature study of InSe doped with GaS revealed that in this case anharmonicity increases with an increase in dopant and an increase in temperature.

    关键词： GaS,doping,Raman scattering,Semiconductor,InSe

    更新于2025-09-04 15:30:14

  • Development of a radiative transfer model for the determination of toxic gases by Fourier transform–infrared spectroscopy with a support vector machine algorithm

    摘要： This report describes a radiative transfer model for Fourier transform-infrared (FT-IR) spectroscopy to create close-to-reality toxic gas spectra by reflecting the unique spectral responses of detectors and using the atmospheric radiative transfer code, MODTRAN. This system can be highly useful in overcoming the limitations for measuring toxic gases in open environments. The emulated gas spectra can be used to train support vector machine (SVM) for chemical gas detection. Its detection performance is evaluated with nerve agents (tabun, sarin, soman, and cyclosarin) and a simulant gas (sulfur hexafluoride) for indoor and outdoor experiments by using two off-the-shelf FT-IR gas detectors. The experimental results show that the proposed SVM algorithm successfully detected and classified targeted gases while reducing false negative and false positive detection rates.

    关键词： support vector machine gas detection,Fourier transform infrared remote sensing,support vector machine,hyperspectral imaging,Fourier transform – infrared spectroscopy,stand-off detection

    更新于2025-09-04 15:30:14

  • The importance of thermal dissociation in CO<sub>2</sub> microwave discharges investigated by power pulsing and rotational Raman scattering

    摘要： The input power of a CO2 microwave plasma is modulated at kHz rate in scans of duty cycle at constant average power to investigate gas heating dynamics and its relation to dissociation e?ciency. Rotational temperature pro?les obtained from rotational Raman scattering reveal peak temperatures of up to 3000 K, while the edge temperature remains cold (500 K). During the plasma “OFF”-period, the gas cools down convectively, but remains overall too hot to allow for strong overpopulation of vibrational modes (2200 K in the core). Fast optical imaging monitors plasma volume variations and shows that power density scales with peak power. As dissociation scales with observed peak rotational temperature, it is concluded that thermal processes dominate. A simple 0D model is constructed which explains how higher power density favors dissociation over radial energy transport. Thermal decomposition is reviewed in relation to quenching oxygen radicals with vibrationally excited CO2, to re?ect on earlier reported record e?ciencies of 90 %.

    关键词： power pulsing,rotational Raman scattering,gas heating dynamics,thermal dissociation,CO2 microwave discharges

    更新于2025-09-04 15:30:14

  • Development of high-voltage nanosecond discharge in strongly non-uniform gas

    摘要： The results of the experimental and numerical study of a high-voltage nanosecond discharge developing through a shock wave in air and combustible mixtures were presented for various in the case of quasi-uniform plasma agree well with the measured ratios of the intensities emitted by the plasma in the high-density plasma. The results of a zero-dimensional simulation uniform when the ionization wave moved from a high-density region to a low-density region. The radiation intensity emitted by the plasma in the low-density region was higher than that neutral density jumps across the wave. The discharge uniformity was investigated using ICCD camera images in a shock tube. The results demonstrated that the discharge plasma became more.

    关键词： high-voltage nanosecond discharge,ICCD camera images,and secondary ionization waves.,plasma uniformity,gas density jump,streamer development,shock wave

    更新于2025-09-04 15:30:14

  • Investigation of gas discharge features during HiPIMS using optical emission spectroscopy

    摘要： The paper presents the results of the investigation of the emission spectra of a gas discharge during high-power impulse magnetron sputtering (HiPIMS) of a titanium target at different power supply parameters. In such mode, the fraction of ionized atoms of the target material in the discharge increases significantly, what affects the properties of the deposited coatings. The characteristic features of the operation of the system in HiPIMS mode were singled out, and also the discharge spectra were compared at high-power impulse and conventional (sputtering on a direct current) operation modes of the magnetron. As a result of the study, it was shown that the use of optical emission spectroscopy during HiPIMS makes it possible to effectively determine the parameters of the stable operation of the system and determine the boundary at which a transition into high-power regime occurs.

    关键词： titanium target,HiPIMS,gas discharge,magnetron sputtering,optical emission spectroscopy

    更新于2025-09-04 15:30:14

  • /epitaxial graphene van der Waals heterostructure

    摘要： We report on direct observation of interface superconductivity in single-unit-cell SnSe2 films grown on graphitized SiC(0001) substrate. The tunneling spectrum in the superconducting state reveals a rather conventional character with a fully gapped order parameter. The occurrence of superconductivity is further confirmed by the observation of vortices under external magnetic field. Through interface engineering, we unravel the mechanism of superconductivity that originates from a two-dimensional electron gas formed at the interface of SnSe2 and graphene. Our finding opens up novel strategies to hunt for and understand interface superconductivity based on van der Waals heterostructures.

    关键词： two-dimensional electron gas,interface superconductivity,van der Waals heterostructure,SnSe2,graphene

    更新于2025-09-04 15:30:14

  • [IEEE 2018 XV International Scientific Conference on Optoelectronic and Electronic Sensors (COE) - Warsaw, Poland (2018.6.17-2018.6.20)] 2018 XV International Scientific Conference on Optoelectronic and Electronic Sensors (COE) - Wavelet Transform Analysis of Temperature Modulated Gas Sensor Response

    摘要： The aim of the study was to evaluate whether it is possible to extract the information about the gas concentration despite the influence of humidity. Commercial semiconductor sensor response was examined under the application of a periodic temperature change. The data was collected using measurement protocol for different concentrations of ammonia at specified levels of relative humidity. In this work we focused on the evaluation of the Discrete Wavelet Transform analysis results obtained during experimental investigation of the single semiconductor gas sensor in the presence of humidified atmosphere containing ammonia. The results of the analysis show that proposed method enable the possibility of determine the low concentrations of ammonia.

    关键词： feature extraction,semiconductor gas sensor,discrete wavelet transform,data analysis,temperature modulation

    更新于2025-09-04 15:30:14

  • Using <sup>220</sup> Rn to calibrate liquid noble gas detectors

    摘要： In this paper, we describe 220Rn calibration source that was developed for liquid noble gas detectors. The key advantage of this source is that it can provide 212Bi–212Po consecutive events, which enables us to evaluate the vertex resolution of a detector at low energy by comparing low-energy events of 212Bi and corresponding higher-energy α-rays from 212Po. Since 220Rn is a noble gas, a hot metal getter can be used when introduced using xenon as the carrier gas. In addition, no long-life radioactive isotopes are left behind in the detector after the calibration is complete; this has clear advantage over the use of 222Rn which leaves long-life radioactivity, i.e., 210Pb. Using a small liquid xenon test chamber, we developed a system to introduce 220Rn via the xenon carrier gas; we demonstrated the successful introduction of 6 × 102 220Rn atoms in our test environment.

    关键词： calibration,vertex resolution,212Bi–212Po consecutive events,220Rn,liquid noble gas detectors

    更新于2025-09-04 15:30:14

  • [IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - A Micro-Hotplate for MEMS Based Gas Sensor

    摘要： This work designed a micro-hotplate for micro-electromechanical systems (MEMS) based gas sensor, in which the heating electrode and the test electrode are placed on the same plane. The micro-hotplate with four pins was optimized the finite element analysis method. The heating electrode and test electrode were made of platinum. The working temperature of heating electrode was controlled by the voltage linear of heating electrode and calibrated through the resistance-temperature characteristic curve and relation curve of voltage and resistance. Infrared thermography microscope directly observed the temperature distribution of the heating electrode at different voltages. The micro-hotplate was used for ethanol detecting based on SnO2 nanosheets and the response reached at 21.4 in 100 ppm ethanol gas.

    关键词： MEMS,micro-hotplate,gas sensor

    更新于2025-09-04 15:30:14

  • Hydrogen Sensing Properties of Co-Doped ZnO Nanoparticles

    摘要： In this study, the gas sensing properties of Co-doped ZnO nanoparticles (Co-ZnO NPs) synthesized via a simple sol-gel method are reported. The microstructure and morphology of the synthesized Co-ZnO NPs were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. Co-ZnO NPs were then used for developing a conductometric gas sensor for the detection, at mild temperature, of low concentration of hydrogen (H2) in air. To evaluate the selectivity of the sensor, the sensing behavior toward some VOCs such as ethanol and acetone, which represent the most important interferents for breath hydrogen analysis, was also investigated in detail. Results reported demonstrated better selectivity toward hydrogen of the Co-ZnO NPs sensor when compared to pure ZnO. The main factors contributing to this behavior, i.e., the transition from n-type behavior of pristine ZnO to p-type behavior upon Co-doping, the modification of oxygen vacancies and acid-base characteristics have been considered. Hence, this study highlights the importance of Co doping of ZnO to realize a high performance breath hydrogen sensor.

    关键词： Co-doped ZnO,gas sensor,sol-gel,nanoparticle,sensing mechanism,hydrogen,ethanol

    更新于2025-09-04 15:30:14