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Accurate Identification of the Sex and Species of Silkworm Pupae Using Near Infrared Spectroscopy
摘要： The present study proposes a novel method to discriminate the sex and species of silkworm pupae using NIR spectroscopy (800–2778 nm). The spectra from 840 silkworm pupae were collected then divided into a calibration set (700) and a test set (140) using the Kennard–Stone (KS) algorithm. The recognition models were built using the radial basis function and neural network (RBF–NN) and support vector machine (SVM) approaches. The species and sex identi?cation results using the RBF–NN and SVM models based on full spectral data achieved a low accuracy of 5% and 33.57%, respectively. To improve the accuracy and decrease the processing time, both principal component analysis (PCA) and linear discriminant analysis (LDA) were used to reduce the data dimensions. The performance of the optimized SVM model (92.14%) was much better than the RBF–NN model (19.29%) based on PCA. Overall, the best discrimination results were obtained using the RBF–NN and SVM models based on LDA, providing an accuracy of 100%. These promising results have shown that the LDA–SVM and LDA–RBF–NN models can accurately recognize the sex and species of silkworm pupae using NIR spectroscopy.
关键词： silkworm pupa,species,NIR spectroscopy,sex
更新于2025-09-09 09:28:46
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Extracting the turbulent flow-field from beam emission spectroscopy images using velocimetry
摘要： The 2D turbulent E × B flow-field is inferred from density fluctuation images obtained with the beam emission spectroscopy diagnostic on DIII-D using the orthogonal dynamic programming velocimetry algorithm. A synthetic turbulence model is used to test the algorithm and optimize it for measuring zonal flows. Zonal flow measurements are found to require a signal-to-noise ratio above ～10 and a zonal flow wavelength longer than ～2 cm. Comparison between the velocimetry-estimated flow-field and the E × B flow-field using a nonlinear gyrokinetic GENE simulation finds that the flow-fields have identical spatial structure and differ only by the mean turbulence phase velocity, which is spatially uniform in this flux tube simulation.
关键词： beam emission spectroscopy,turbulent flow-field,zonal flows,velocimetry,GENE simulation
更新于2025-09-09 09:28:46
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Development of high-speed vacuum ultraviolet spectroscopy using a modified Seya-Namioka monochromator and channel electron multiplier detector in the HL-2A tokamak
摘要： A high-speed vacuum ultraviolet monochromator is developed for the HL-2A tokamak through the introduction of a novel channel electron multiplier in a modified Seya-Namioka spectrometer. A good signal to noise ratio of above 2000 is attained in the development phase of the system with typical operating parameters for observing routine HL-2A plasmas. The wavelength calibration is performed using characteristic line emissions from a hollow cathode light source with helium and argon discharges. The first measurement result of the monochromator at a sample rate of 60 kHz is presented in comparison with the visible Dα signals.
关键词： channel electron multiplier detector,HL-2A tokamak,Seya-Namioka monochromator,high-speed vacuum ultraviolet spectroscopy
更新于2025-09-09 09:28:46
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AIP Conference Proceedings [Author(s) PHYSICS, TECHNOLOGIES AND INNOVATION (PTI-2018): Proceedings of the V International Young Researchers’ Conference - Ekaterinburg, Russia (14–18 May 2018)] - Reduction of uranium(VI) species in alkali chloride melts: An electronic absorption spectroscopy study of formation of uranium(V) ions
摘要： Reaction of uranyl chloride with gaseous hydrogen was studied in a range of alkali chloride based melts between 350 and 850 oC. The reaction leads to the formation of soluble uranium(V) dioxochloro-species and solid uranium dioxide. In situ electronic absorption spectroscopy was employed to follow the reaction. Electronic absorption spectra of uranium(V) dioxo-species were recorded between 300 and 1600 nm. The effect of temperature and second coordination sphere cations on the absorption spectra is discussed.
关键词： alkali chloride melts,hydrogen reduction,uranium(V),electronic absorption spectroscopy,uranyl chloride
更新于2025-09-09 09:28:46
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Structural, Dielectric and Impedance Spectroscopic Studies on Fe Doped BaTiO <sub/>3</sub>
摘要： Compositions with x=0.03, 0.05 and 0.10 are synthesized in the system BaFexTi1–xO3 using conventional solid state reaction method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). XRD patterns reveal the coexistence of tetragonal and hexagonal phases which are strongly affected by the level of Fe doping. The hexagonal phase increases with increasing x, being maximum for x=0.10. SEM images show the presence of agglomerated grains which increase in size with amount of Fe doping. SEM for x=0.10 shows mostly rod-like or rectangular grains indicating predominantly hexagonal phase. Dielectric and impedance measurements have been carried out in the frequency range 20 Hz-1 MHz as a function of temperature (300-650 K). The samples with x=0.03 and 0.05 exhibit diffuse phase transition. Using complex impedance analysis equivalent circuit models have been developed which represent the data well and successfully separate out the contributions of tetragonal phase, hexagonal phase, grain boundaries and electrodes.
关键词： Impedance spectroscopy,Fe doped BaTiO3,Dielectric response,Diffuse phase transition
更新于2025-09-09 09:28:46
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(111)Si thin layers detachment by stress-induced spallation
摘要： In this work, results of controlled detachment of (111) silicon by stress induced spalling (SIS) process, which is based on a gluing on a metallic stressor layer by an epoxy adhesive on top of a silicon substrate, are presented. It is shown that silicon foils mainly (1x1) cm2 with different thicknesses (~50-170 μm) can be successfully detached using different materials (steel, copper, aluminum, nickel and titanium) as stressor layers with thicknesses ~50-500 μm. Such detachment can be realized by dipping of a stressor/glue/silicon wafer based structure into liquid nitrogen. As a result, Si foils with different thicknesses from ~50 μm to ~170 μm can be detached. An analytical and numerical approaches based on principles of linear elastic fracture mechanics is developed and they are shown that such approaches can predict general trends and conditions for the detachment of silicon foils with desired thicknesses using a stressor layer. Raman spectroscopy analysis of the residual stresses in detached silicon foils shows, that tensile stresses (up to - 36MPa) as well as higher value compressive stresses (up to ~444 MPa) are present in such foils. Moreover, optical and scanning electron microscopy (SEM) measurements show that surface of the detached foils exhibits some periodic lines originated by stresses.
关键词： Exfoliation of silicon,Thermal stress,Raman spectroscopy,Kerf-free,photovoltaics (PV)
更新于2025-09-09 09:28:46
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VO <i> <sub/>n</sub></i> Complexes in RTA Treated Czochralski Silicon Wafers Investigated by FTIR Spectroscopy
摘要： Oxygen-vacancy complexes formed after rapid thermal annealing in silicon wafers were investigated by FTIR spectroscopy at 6 K. It was found that VO4 is the only detectable complex. The concentration of VO4 complexes increases with increasing temperature of RTA treatment in the temperature range between 1250?C and 1400?C. The concentration at maximal temperature is equal to 4.5 × 1013 cm?3. The experimental results were compared with concentrations of VOn complexes in silicon wafers obtained using ab-initio calculations combined with rate equation modelling. The simulated concentration of VO4 corresponds well to the measured concentration. The bulk microdefect density increases with increasing VO4 concentration. The vacancies stored in VOn complexes after RTA are slowly released during further annealing and enhance oxide precipitation.
关键词： VO4 complexes,silicon wafers,Rapid thermal annealing,FTIR spectroscopy,oxygen precipitation
更新于2025-09-09 09:28:46
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Hybrid and pristine polyalkylthiophene Langmuir-Schaefer films: Relationships of electrical impedance spectroscopy measurements, barrier properties and polymer nanostructure
摘要： Molecular organization in solid state plays a central role on organic devices performance. In this sense, a thorough investigation of thin films with application in organic electronics is imperative. This work addressed the fabrication and the morphological, optical and electrical characterization of Langmuir-Schaefer (LS) films of poly(3-hexylthiophene) (P3HT), pristine and mixed with stearic acid (SA), and their use as the active layer in organic Schottky diodes. The floating materials isotherms showed the SA molecules acting as a stabilizer for the P3HT in the Langmuir trough. Moreover, deposited P3HT:SA films present significant morphological changes, an improvement of the films overall structural ordering and a more effective charge transport within the active layer through electrical outcome. The alternating current measurements along with theoretical fitting, using equivalent electrical circuits, provided a good alternative to investigate the interfacial effects of the P3HT and P3HT:SA films deposited onto Al and Au electrodes.
关键词： Electrical impedance spectroscopy,Structure-property relations,Polythiophene,Langmuir-Schaefer,Thin films
更新于2025-09-09 09:28:46
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Growth of 1T’ MoTe <sub/>2</sub> by Thermally-Assisted Conversion of Electrodeposited Tellurium Films
摘要： Molybdenum ditelluride (MoTe2) is a transition metal dichalcogenide (TMD) which has two phases stable under ambient conditions, a semiconducting (2H) and semimetallic (1T’) phase. Despite a host of interesting properties and potential applications, MoTe2 is one of the less-studied TMDs, perhaps due its relatively-low abundance in nature or challenges associated with its synthesis, such as the toxicity of most precursors. In this report, we describe the fabrication of thin films of phase-pure 1T’ MoTe2 using pre-deposited molybdenum and electrodeposited tellurium layers, at the relatively low temperature of 450?C. This method allows control over film geometry and over the tellurium concentration during the conversion. The MoTe2 films are characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy and electron microscopies. When applied as a catalyst for the hydrogen evolution reaction, the films display promising initial results. The MoTe2 films have a Tafel slope of below 70 mV dec-1 and compare favorably with other MoTe2 catalysts reported in the literature, especially considering the inherently-scalable fabrication method. The variation in electrocatalytic behavior with thickness and morphology of the films is also investigated.
关键词： 1T’ phase,thin-film,hydrogen evolution reaction,Raman spectroscopy,MoTe2,electrocatalysis
更新于2025-09-09 09:28:46
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Engineering the Palladium–WSe <sub/>2</sub> Interface Chemistry for Field Effect Transistors with High Performance Hole Contacts
摘要： Palladium has been widely employed as a hole contact to WSe2 and has enabled, at times, the highest WSe2 transistor performance. However, there are orders of magnitude variation across the literature in Pd–WSe2 contact resistance and ION/IOFF ratios with no true understanding of how to consistently achieve high–performance contacts. In this work, WSe2 transistors with impressive ION/IOFF ratios of 106 and Pd–WSe2 Schottky diodes with near–zero variability are demonstrated utilizing Ohmic–like Pd contacts through deliberate control of the interface chemistry. The increased concentration of a PdSex intermetallic is correlated with an Ohmic band alignment and concomitant defect passivation, which further reduces the contact resistance, variability, and barrier height inhomogeneity. The lowest contact resistance occurs when a 60 minute post metallization anneal at 400 °C in forming gas (FG) is performed. X-ray photoelectron spectroscopy indicates this FG anneal produces 3× the concentration of PdSex and an Ohmic band alignment, in contrast to that detected after annealing in ultra–high vacuum, during which a 0.2 eV hole Schottky barrier forms. Raman spectroscopy and scanning transmission electron microscopy highlight the necessity of the fabrication step to achieve high–performance contacts as no PdSex forms and WSe2 is unperturbed by room temperature Pd deposition. However, at least one WSe2 layer is consumed by the necessary interface reactions that form PdSex requiring strategic exploitation of a sacrificial WSe2 layer during device fabrication. The interface chemistry and structural properties are correlated with Pd–WSe2 diode and transistor performance and the recommended processing steps are provided to enable reliable high–performance contact formation.
关键词： annealing,palladium,WSe2,interface chemistry,X-ray photoelectron spectroscopy,transistor,metal contact
更新于2025-09-09 09:28:46