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[IEEE 2019 IEEE 5th International Workshop on Metrology for AeroSpace (MetroAeroSpace) - Torino, Italy (2019.6.19-2019.6.21)] 2019 IEEE 5th International Workshop on Metrology for AeroSpace (MetroAeroSpace) - Low temperature point contact spectroscopy and transport measurements on filled skutterudite compounds
摘要： Several members of the RPt4Ge12 skutterudites class (R = Sr, Ba, Th, La, Pr) show at low temperature the phenomenon of superconductivity, with R = Pr exhibiting the highest transition temperature of about 8 K. PrPt4Ge12 shows as well a wide variety of strongly correlated electron behavior, including metal-insulator transitions, spin fluctuations, and various magnetically ordered states. In this work, we have applied the point contact spectroscopy to investigate the superconducting order parameter of the PrPt4Ge12 compound. Superconductivity in PrPt4Ge12 is progressively suppressed by partially substituting the Pr ions with Ce ions. For this reason, electrical resistance measurements as a function of the temperature (R-T), in different applied magnetic fields have also been performed and analysed on Pr1-xCexPt4Ge12 samples for x = 0, 0.07, 0.10.
关键词： Electrical Resistance Measurements,Superconducting Materials,Tunneling
更新于2025-09-11 14:15:04
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Investigation on structural, optical and photovoltaic properties of Barium doped cuprous oxide thin films by nebulizer spray technique
摘要： In present work, pure and barium (Ba) doped cuprous oxide (Cu2O) films are coated on heated glass substrate by Nebulizer spray technique (NST) by taking different doping concentration (0%, 3%, 5%, and 7%) of Ba. The XRD, AFM, optical, electrical resistivity and solar cell studies of pure and Ba doped samples were discussed. The XRD pattern confirms the polycrystalline cubic structure with a preferred (111) plane orientation. Atomic force microscopy (AFM) reveals the spherical shape nano particles. The Raman analysis confirmed the cuprous oxide phase of prepared films. The Optical analysis was revealed the decreasing in band gap with increasing barium doping concentration. The photoluminescence studies confirmed the single emission peak obtained at 630 nm for all the films corresponds to Cu2O phase. The electrical resistivity is found to be 0.45 × 102 Ω cm for 7% Ba doped Cu2O thin film and the photovoltaic properties of the fabricated solar cell i.e. FTO/n-ZnO/p-7% Ba:Cu2O/Ag was formed for 7% Ba: Cu2O thin film. Further, the efficiency of the fabricated solar cell is found to be 0.85%.
关键词： solar cell,Barium doped,AFM studies,spray pyrolysis,electrical measurements
更新于2025-09-11 14:15:04
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High-Performance Smooth-Walled Horn Antennas for THz Frequency Range: Design and Evaluation
摘要： Traditionally, corrugated conical horn antennas have been the main choice for use in astronomical receivers in the range of millimeter and submillimeter waves. They present low cross-polar level and high coupling efficiency into the fundamental Gaussian mode. However, this type of antenna is difficult to manufacture, inevitably increasing its price and extending the production process. In this work, we present two kinds of feed horn antennas, aimed for use in a frequency range equivalent to ALMA Band 6 (211-275 GHz), which can be fabricated in a much simpler way with conventional machining tools. Specifically, we present the design and performance comparison of smooth-walled spline-profile horns in two geometries, diagonal and conical. Optimization of the designs has been made by means of an algorithm that allowed us to obtain models whose electrical and mechanical characteristics make them competitive when compared with corrugated horns. In particular, they are 40% shorter than conventional corrugated horns suited for this band, representing an advantage given the stringent space constraints of most astronomical receivers. We also demonstrate that they can be coupled efficiently to an astronomical-grade optical system, using ALMA Band-6 receiver as an example. Furthermore, we have constructed the diagonal horn and characterized it thoroughly. Experimental results of the radiation pattern at room temperature show a good cross-polar performance with levels below ?20 dB and gaussicity above 96%. Our calculations show a good antenna-efficiency level with losses less than 1%. All these properties demonstrate the feasibility of this type of horns to become the main option at the time of choosing a feed system for cutting-edge astronomical applications.
关键词： diagonal horn,spline-profile,conical horn,ALMA,optical train calculation,radiation pattern measurements,profile optimization,millimeter/submillimeter wave,split-block
更新于2025-09-11 14:15:04
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[IEEE 2019 4th International Symposium on Instrumentation Systems, Circuits and Transducers (INSCIT) - Sao Paulo, Brazil (2019.8.26-2019.8.30)] 2019 4th International Symposium on Instrumentation Systems, Circuits and Transducers (INSCIT) - Sensitivity Analysis of Controlled-Temperature Thermoresistive-based Radiometers
摘要： Currently, renewable energy is being explored all to solar radiation, many solutions are currently available on the market and many more are being developed in industry and academy. In this scenario, a thermoresistive-based radiometer would provide information regarding solar radiation to solar energy systems at a very low cost. In this paper, the sensitivity of radiometers based on thermoresistive electrical equivalence are analyzed. It is verified that the change of the temperature of the sensor affects considerably its sensitivity. Another architecture was proposed in which the difference of temperature between the sensor and the environment is made constant. Here, we propose the most efficient difference of temperature in order to provide best sensitivity-wise measurements. Also, architectures employing PTC and NTC type sensors, with analog voltage and pulse width modulated output signals, are analyzed and compared regarding their sensitivity.
关键词： thermoresistive sensors,radiation,solar energy,measurements
更新于2025-09-11 14:15:04
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Observation of scalable sub-Poissonian-field lasing in a microlaser
摘要： Sub-Poisson field with much reduced fluctuations in a cavity can boost quantum precision measurements via cavity-enhanced light-matter interactions. Strong coupling between an atom and a cavity mode has been utilized to generate highly sub-Poisson fields. However, a macroscopic number of optical intracavity photons with more than 3 dB variance reduction has not been possible. Here, we report sub-Poisson field lasing in a microlaser operating with hundreds of atoms with well-regulated atom-cavity coupling and interaction time. Its photon-number variance was 4 dB below the standard quantum limit while the intracavity mean photon number scalable up to 600. The highly sub-Poisson photon statistics were not deteriorated by simultaneous interaction of a large number of atoms. Our finding suggests an effective pathway to widely scalable near-Fock-state lasing at the macroscopic scale.
关键词： microlaser,Sub-Poissonian-field lasing,cavity-enhanced light-matter interactions,quantum precision measurements,macroscopic sub-Poissonian field stabilization
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP) - Bochum, Germany (2019.7.16-2019.7.18)] 2019 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP) - Experimental Investigation of Terahertz Wave Scattering by Statistically Controlled Rough Surfaces
摘要： In this work, the experimental investigation of electromagnetic wave scattering by statistically controlled rough surfaces in the lower THz band is demonstrated. Rough surfaces with height fluctuations following normal statistics are fabricated using two different 3D printing techniques. The results presented here confirm that the surface roughness has a noticeable effect on the level of the diffuse scattering energy. In the future, the applied method can be used to validate analytical models as well as to gain scattering patterns from more complicated rough surface structures which fall outside the limits of most analytical approximations.
关键词： scattering measurements,statistically controlled rough surfaces,THz communication
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE Photonics Conference (IPC) - San Antonio, TX, USA (2019.9.29-2019.10.3)] 2019 IEEE Photonics Conference (IPC) - Optical Sensor Behavior Prediction using LSTM Neural Network
摘要： Optical fiber-based-sensors proved capable of enduring various harsh environments. Long-short-term memory (LSTM) neural-networks are often used for datasets with long- dependences. Here, rare FBG measurements collected from a neutron reactor core were used to build a neural-network capable of predicting the future events inside the reactor.
关键词： Fiber Bragg grating,nuclear reactor core measurements,long-short-term memory,recurrent neural networks
更新于2025-09-11 14:15:04
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Development of a LIDAR array to study and classify wakes at the U.S. Department of Energy (DOE)/Sandia National Laboratories Scaled Wind Farm Technology (SWiFT) facility
摘要： Wind turbine wake has the wind speed deficit and the increased turbulent flow to the downstream turbines as signatures. Various experiments and simulations have been performed over the years to investigate the wake parameters; however, a statistical characterization of wake states is still to be uncovered. An innovative wake measurement approach that uses five ground-based Spidar Light Detection and Ranging (LIDAR) has been developed in partnership with Texas Tech University (TTU), Sandia National Laboratories, and Pentalum Technologies to develop, test, and validate a system and methodology that enables the capture of statistically significant wake dynamics in real atmospheric conditions. This article will discuss the potential of this new direct detection remote sensing equipment for studying the wake states as well as report the validation process of the LIDAR and the feasibility of continuing to pursue the primary purpose of the initiative.
关键词： Wake characterization,LIDAR,field measurements
更新于2025-09-11 14:15:04
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Analysis of the Processing‐Pressure Dependent Refractive Index of Polycarbonate by Transmission Measurements of Glass‐Filled Specimen
摘要： In this study, the influence of pressure during processing on the refractive index (RI) of polycarbonate (PC) was investigated by transmission measurements on glass-filled samples with a spectrometer. In order to isolate the pressure dependence of the RI from other influencing parameters such as cooling rate, orientation and stress states, the samples were prepared in a pressure-specific volume-Temperature (pvT) instrument under constant cooling rate and temperature history and without shear effects. Subsequently, the RI was determined at the intersection of the dispersion curves of the glass and the polymer by evaluating the wavelength of the maximal transmission of the samples. The mean RI over the entire cross section of the sample is determined by the transmission measurements without complex sample preparation. The investigations show that the RI of PC increases by 3.26 E-6 per bar with increasing pressure.
关键词： glass-filled specimen,processing-pressure,refractive index,polycarbonate,transmission measurements
更新于2025-09-11 14:15:04
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Aging Effect of a Cu(In,Ga)(S,Se) <sub/>2</sub> Absorber on the Photovoltaic Performance of Its Cd‐Free Solar Cell Fabricated by an All‐Dry Process: Its Carrier Recombination Analysis
摘要： Cd-free Cu(In,Ga)(S,Se)2 (CIGSSe) solar cells are fabricated by an all-dry process (a Cd-free and all-dry process CIGSSe solar cell) with aged CIGSSe thin film absorbers. The aged CIGSSe thin films are kept in a desiccator cabinet under partial pressure of oxygen of ≈200 Pa for aging time up to 10 months. It is reported for the first time that aged CIGSSe thin film with increased aging time results in significant enhancement of photovoltaic performance of Cd-free and all-dry process CIGSSe solar cells, regardless of the alkali treatment. Based on carrier recombination analysis, carrier recombination rates at the interface and in the depletion region of the Cd-free and all-dry process CIGSSe solar cells are reduced owing to avoidance of sputtering damage on CIGSSe absorber surface, which is consistent with the strong electron beam-induced current signal near CIGSSe surface after the increased aging time. It is implied that the interface and near-surface qualities are clearly improved through the increased aging time, which is attributable to the self-forming of Inx(O,S)y near CIGSSe surface, which acts as a buffer layer. Ultimately, the 22.0%-efficient Cd-free CIGSSe solar cell fabricated by all-dry process is achieved with the aged Cs-treated CIGSSe absorber with the aging time of 10 months.
关键词： all-dry process,EBIC measurements,Cd-free Cu(In,Ga)(S,Se)2 solar cells,aging time,carrier recombination rate
更新于2025-09-11 14:15:04