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[IEEE 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Saint Petersburg, Russia (2018.10.22-2018.10.23)] 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Study of Gas-Sensitive Properties of Zinc Oxide Nanorod Array at Room Temperature
摘要： In this paper, we present a technique for the synthesis of zinc oxide nanorods and the study of their sensitivity to organic solvent vapors. Zinc oxide nanorods were synthesized by hydrothermal method. Investigation of gas-sensitive properties was carried out by the method of impedance spectroscopy. Studies of gas-sensitive properties of zinc oxide showed a significant response of the system to the vapor of reducing gases at room temperature. It is shown that the thickness of the seed layer and, correspondingly, the density of the structure on the basis of ZnO nanorods, strongly affect the sensitivity of the sensor.
关键词： impedance spectroscopy,nanorods,hydrothermal synthesis,zinc oxide,gas sensors
更新于2025-09-04 15:30:14
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Effect of Deposition Method on Valence Band Offsets of SiO <sub/>2</sub> and Al <sub/>2</sub> O <sub/>3</sub> on (Al <sub/>0.14</sub> Ga <sub/>0.86</sub> ) <sub/>2</sub> O <sub/>3</sub>
摘要： There are often variations in reported valence band offsets for dielectrics on semiconductors and some of the reasons documented include metal or carbon contamination, interfacial disorder, variations in dielectric composition, thermal conditions, strain, and surface termination effects. In this paper we show that there are differences of up to 1 eV in band alignments for the common gate dielectrics SiO2 and Al2O3 on single crystal (Al0.14Ga0.86)2O3, depending on whether they are deposited by sputtering or Atomic Layer Deposition. In the case of Al2O3, this changed the band alignment from nested (type I) to staggered gap (type II). The valence band offset at each heterointerface was measured using X-Ray Photoelectron Spectroscopy and was determined to be ?0.85 ± 0.15 eV for sputtered Al2O3 and 0.23 ± 0.04 eV for ALD Al2O3 on β-(Al0.14Ga0.86)2O3, while for SiO2 it was 0.6 ± 0.10 eV for sputtered and 1.6 ± 0.25 eV for ALD. These results are consistent with recent results showing that the surface of Ga2O3 and related alloys are susceptible to severe changes during exposure to energetic ion environments.
关键词： Al2O3,(Al0.14Ga0.86)2O3,SiO2,valence band offsets,Atomic Layer Deposition,X-Ray Photoelectron Spectroscopy,sputtering
更新于2025-09-04 15:30:14
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Correlation of Near Infrared Spectroscopy Measurements with the Surface Roughness of Wood
摘要： The surface roughness of Chinese fir and Eucalyptus wood samples were measured using the stylus profile method in order to investigate the correlation between near infrared (NIR) spectroscopy and surface roughness. The results showed that the NIR spectra absorption showed differences among samples from different surface roughnesses, and the absorption decreased with the increase of the surface roughness. A strong relationship was found between the surface roughness parameters, i.e., the arithmetical mean deviation of the profile (Ra), the ten-point height of irregularities (Rz), and the maximum height of profile (Ry). Based on the NIR spectra of the Chinese fir wood samples and the mixed wood samples of the two wood species, and the correlation coefficients of these two types of wood samples in a calibration set were 0.77 to 0.83 and 0.67 to 0.74, respectively. A relatively poor correlation was found in the model based on the Eucalyptus samples; however, it was still significant. These results suggested that there was relative information about the surface roughness from the NIR spectra, which further illustrated that the surface roughness may influence the effect of models for wood properties built by NIR data.
关键词： Near infrared spectroscopy,Correlation,Wood,Surface roughness
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 7th International Conference on Photonics (ICP) - Kuah (2018.4.9-2018.4.11)] 2018 IEEE 7th International Conference on Photonics (ICP) - Characterizing Inhibitor Content of Transformer Oil in the UV-Visible Waveband
摘要： Over the years, transformer oil has been used in majority of the power transformers to provide a reliable insulating system that is effective against dielectric stresses. Oxidation often occurred in transformer oil in the presence of oxygen and moisture which will affect the stability and insulating properties of the oil. The oxidation process cannot be eliminated but it can be delayed with the presence of inhibitor content. Even though inhibitor content can reduce the oxidation rate, the amount of inhibitor content still depletes over time. Thus, a monitoring system to detect the inhibitor content concentration is very crucial as it will be able to prolong the life span of the transformer. This paper focuses on the optical characterization of inhibitor content in transformer oil by utilizing the ultraviolet-visible (UV-Vis) spectroscopy technique. It was found that oil samples with inhibitor content produce multiple absorbance peaks in the range of 350 nm to 500 nm. A clear difference in peak absorbance near 450 nm indicates the difference in the inhibitor content concentrations. Based on the results of this work, a portable and low cost optical sensing device can potentially be developed for the detection of inhibitor content in transformer oil using UV-Vis spectroscopy.
关键词： Inhibitor,Visible spectroscopy,Power Transformers,Transformer Oil
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Krakow, Poland (2018.10.16-2018.10.18)] 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Development of an iTomography infrastructure for non-destructive documentation of cultural heritage objects
摘要： In this paper, an new setup for the non-destructive scanning for cultural heritage applications is proposed. First, a multi-degree of freedom mechanical implementation is designed, for multiple angle and distance scanning of artworks via different modalities. Moreover, a specialized acquisition and control software is developed consequently created for the uni?ed platform. Additionally, various, onboard, post-processing image registration algorithms are realized for the combination of images originating on various sensors. The ?nal setup is tested on a mock-up icon, verifying the merits of the developed prototype for cultural heritage science work and research.
关键词： mapping tomography,ultrasound,spectroscopy,image processing,heritage science,non destructive testing
更新于2025-09-04 15:30:14
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Quantitative Evaluation of Broadband Photoacoustic Spectroscopy in the Infrared with an Optical Parametric Oscillator
摘要： We evaluate the spectral resolution and the detection thresholds achievable for a photoacoustic spectroscopy (PAS) system in the broadband infrared wavelength region 3270 nm to 3530 nm driven by a continuous wave optical parametric oscillator (OPO) with P ≈ 1.26 W. The absorption spectra, IPAS(λi), for diluted propane, ethane and methane test gases at low concentrations (c ～ 100 ppm) were measured for ～1350 discrete wavelengths λi. The IPAS(λi) spectra were then compared to the high resolution cross section data, σFTIR, obtained by Fourier Transform Infrared Spectroscopy published in the HITRAN database. Deviations of 7.1(6)% for propane, 8.7(11)% for ethane and 15.0(14)% for methane with regard to the average uncertainty between IPAS(λi) and the expected reference values based on σFTIR were recorded. The characteristic absorption wavelengths λres can be resolved with an average resolution of δλres ～ 0.08 nm. Detection limits range between 7.1 ppb (ethane) to 13.6 ppb (methane). In an additional step, EUREQA, an artificial intelligence (AI) program, was successfully applied to deconvolute simulated PAS spectra of mixed gas samples at low limits of detection. The results justify a further development of PAS technology to support e.g., biomedical research.
关键词： photoacoustic spectroscopy,optical-parametric oscillator,PAS,gas sampling,hydrocarbons,spectral deconvolution,EUREQA,OPO
更新于2025-09-04 15:30:14
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DVD Review
摘要： This DVD course, “Basic Concepts in NMR”, is exactly what the title claims – a very thorough and detailed description of the underlying “concepts” that one needs to know to fully understand one-dimensional NMR experiments. Since I have been an industrial NMR spectroscopist training scientists to do NMR for over 40 years, I have a full appreciation for the amount of time this course would have saved me. The course explores the basic theory behind NMR experiments and even explains the components of the hardware necessary to obtain NMR data. The author’s presentations show the result of decades of teaching this topic. He presents each concept clearly and at a pace that allows the student to think about what the lessons mean. He frequently relates abstract principles to more easily understood physical observations such as his use of a common spring to illustrate the rate of return to equilibrium of excited nuclei during the relaxation process.
关键词： spectroscopy,DVD course,NMR,basic concepts
更新于2025-09-04 15:30:14
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Impact of Low‐Frequency Vibrations on Charge Transport in High‐Mobility Organic Semiconductors
摘要： Despite decades of intensive studies of charge transport in organic semiconductors (OSs), understanding of mechanisms underpinning efficient charge transport in them remains elusive. Recently, it has been suggested that low-frequency (LF) vibrations are a limiting factor of charge transport in high-mobility OSs. Nevertheless, the relationship between the molecular structure, crystal packing, LF vibrations, and charge transport is still obscured. This hinders the focused search of high-mobility OSs so that researchers rely mainly on trial-and-error method. This review presents theoretical and experimental approaches to studying the LF vibrations and their role in charge transport with a focus on recent results. It is anticipated that tight cooperation between experimentalists and theorists will yield an advanced understanding of LF vibrations in OSs and their impact on charge transport. This will guide the design of novel high-mobility organic semiconductors for organic electronics.
关键词： structure–property relationship,organic electronics,Raman spectroscopy,electron–phonon interaction,charge mobility
更新于2025-09-04 15:30:14
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Recording Raman Spectra Using a Dynamic Fourier Transform Spectrometer
摘要： We have developed a dynamic Fourier transform spectrometer for recording Raman spectra in the near-IR range (800–1100 nm). Stability and reliability of operation of the spectrometer is achieved by using corner re? ectors in the design as mirrors in the main channel. In order to record a weak Raman signal, we set up a white light channel in the spectrometer which enables locking into the zero optical path difference when summing the interferograms over several scans. A reference channel with sampling frequency λ/4 lets us improve the sampling accuracy and the signal-to-noise ratio of the emission spectra. Using our spectrometer, we recorded the Raman spectra of test substances with known positions of the emission lines: 1,4-bis(5-phenyl-2-oxazolyl)benzene (POPOP, C24H16N2O2), stilbene (C14H12), acetylsalicylic acid (C9H8O4). Comparison of the POPOP Raman spectra obtained on the dynamic Fourier transform spectrometer and a diffraction spectrometer for the same experimental conditions showed that they qualitatively matched, and the time required to record the spectrum on the dynamic Fourier transform spectrometer was 4 times shorter.
关键词： Raman spectroscopy,dynamic Fourier transform spectrometer,white-light channel,Fourier transform spectrometer in the visible and near-IR ranges,corner re? ector
更新于2025-09-04 15:30:14
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Structural, optical, and dielectric studies of LaFe1?xMoxO3 (x?=?0.0, 0.5) perovskite materials
摘要： The structural, optical, and dielectric properties of LaFe1?xMoxO3 (x = 0.0, 0.5) synthesized by the sol–gel method were investigated by X-ray diffraction (XRD), Raman scattering, and impedance spectroscopy. XRD analysis revealed that the x = 0.5 compound is single-phase and orthorhombic, with space group Pbnm, similar to the parent x = 0.0 compound but with larger lattice parameters and/or a larger unit-cell volume. The Raman scattering spectra revealed local lattice distortions in the x = 0.5 compound and spin–phonon coupling related to the magnetic transition (Néel) temperature. The impedance data were well fitted with an R(R1-CPE1)//(R2-CPE2) equivalent electrical circuit, demonstrating the contributions of both grains and grain boundaries. The temperature (300–500 K) and frequency (100 Hz–1 MHz) dependences of the dielectric properties showed that Mo substitution adversely affected the dielectric parameters.
关键词： X-ray diffraction,LaFe1?xMoxO3,impedance spectroscopy,Raman scattering,sol–gel method,dielectric properties
更新于2025-09-04 15:30:14