- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2020 International Conference on Computation, Automation and Knowledge Management (ICCAKM) - Dubai, United Arab Emirates (2020.1.9-2020.1.10)] 2020 International Conference on Computation, Automation and Knowledge Management (ICCAKM) - 35.83% Efficient Non-Toxic Perovskite Solar Cell using Copper Iodide and Tin-oxide
摘要： Receiver operating characteristic (ROC) curve is a plot traced out by pairs of false-positive rate and true-positive rate according to various decision threshold settings. The area under the ROC curve (AUC) is widely used as a figure of merit to summarize a diagnostic system’s performance, a binary classifier’s overall accuracy, or an energy detector’s power. Exploiting the equivalent relationship between the sample version of AUC and Mann Whitney U statistic (MWUS), in this paper, we develop an efficient algorithm of linearithmic order, based on dynamic programming, for unbiased estimation of the mean and variance of MWUS. Monte Carlo simulations verify our algorithmic findings.
关键词： receiver operating characteristic (ROC),dynamic programming,Area under the curve (AUC),Mann-Whitney U statistic (MWUS)
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Realization and Use of an IR Camera for Laboratory and On-field Electroluminescence Inspections of Silicon Photovoltaic Modules
摘要： Electroluminescence (EL) is a non-destructive technique, which detects the most common defects in Photovoltaic (PV) modules. High resolution EL images are generally obtained by infrared-sensitive cameras equipped with different semiconductors (indium gallium arsenide or silicon sensors). In the present work, a procedure is proposed to build and set up a high resolution EL camera for crystalline Si modules, equipped with a low-cost Si sensor. It can be used to perform EL test both indoor (lab) and outdoor (on-field). Experimental results from real PV plant highlight the combined use of I-V curves and EL images, for determining the amount of power losses and their causes.
关键词： electroluminescence,faults,maintenance,photovoltaic,current-voltage characteristic
更新于2025-09-19 17:13:59
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[IEEE 2019 24th Microoptics Conference (MOC) - Toyama, Japan (2019.11.17-2019.11.20)] 2019 24th Microoptics Conference (MOC) - Fundamental Study of Saturation Output Power on Quantum Dot Semiconductor Optical Amplifier (SOA) under High Temperature (85 ?°C)
摘要： This paper proposed a new crossbeam ultrasonic motor, which was made of a cross-shaped metal frame and eight pieces of lead zirconate titanate ceramic plates with a size of 10 mm × 3 mm × 1 mm. Two cross-cone-shaped horns were machined at two ends of the crossbeam, and the tips of the horns served as the driving feet. Ellipse trajectories of the two driving feet were generated by superimposing two orthogonal ?rst bending vibrations with the same resonance frequency but a temporal shift of 90?. A Symmetric structure of the proposed ultrasonic motor solved the problem of mode frequencies degeneracy. A new method to excite these two bending vibrations was proposed. Finite-element method simulation was developed to obtain the vibration characteristics of the crossbeam motor. The new excitation method was compared with the traditional one, and it was found that the vibration amplitudes of the driving feet under the new excitation method were about three times that of the traditional one. At last, experiments were accomplished on a fabricated prototype. The two tested ?rst bending resonance frequencies agreed well with each other at ～40.5 kHz. Mechanical output performance of the prototype was tested; the maximum speed was ～64 r/min, and the maximum output torque was ～10.4 mN · m. This paper provides a new idea for an ultrasonic motor with a miniature structure and also a new excitation method for bending vibration.
关键词： vibration characteristic,Crossbeam,bending vibration,excitation method,ultrasonic motor
更新于2025-09-19 17:13:59
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Temperature-Independent Performance of an 8-Layer ?? ~1.3 ??m InAs/GaAs Quantum-Dot Laser
摘要： We report high-performance broad-area eight-layer InAs/GaAs quantum-dot lasers (QDLs) emitting at 1.3 μm in the pulse and continuous-wave (CW) operations. Operational characteristics of the fabricated QDLs, including the emission wavelength, output power, threshold-current density, di?erential quantum e?ciency, and characteristic temperature, are investigated at di?erent temperatures. For as-cleaved facets of 100 μm wide and 1 mm cavity-length device, an output power of 100 mW is achieved at 1 kHz with 5% duty cycle and 49 mW in the CW operation. The device exhibits a threshold-current density of 56 A/cm2 at room temperature in both the operating modes and increases to 71 and 80 A/cm2 the in the pulse and CW modes, respectively, at 343 K. Over a temperature range of 298 K to 343 K, we calculate the threshold characteristic temperature of 166 K and 119 K and slope-e?ciency characteristic temperature of 2061 K and 408 K in the pulse and CW modes, respectively. The laser exhibits di?erential quantum e?ciency of 41% and 32% in the pulse and CW mode, respectively. We observed that the device exhibited negligible dependence over a temperature range of 298 K to 343 K.
关键词： characteristic temperature,quantum-dot laser,di?erential quantum e?ciency,semiconductor laser
更新于2025-09-19 17:13:59
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New Wafer-Level High-Frequency Characterization of Coupled Transmission Lines
摘要： In this article, a new experimental characterization technique for coupled transmission lines is presented. Three specific experimental test patterns (E-, F-, and G-type structures) that can individually characterize the electromagnetic coupling of two coupled lines are developed and fabricated on the same wafer using a 0.18-μm CMOS process. Since the devised test patterns are two-port networks, well-established two-port network characterization techniques can be exploited. Transmission line model parameters (i.e., propagation constants and characteristic impedances) associated with the three two-port test patterns can be directly determined from the measured S-parameters, followed by circuit model parameters (R, L, C, and G) for two coupled lines. Without rigorous equipment calibration and deembedding parasitic effects, experimental characterizations for two coupled lines using four-port network S-parameter measurements may yield physically ambiguous data above 10 GHz due to the parasitic resonances, whereas the proposed technique can determine stable and accurate network parameters over a broad frequency band. To further support the validity of the proposed technique, they are compared with data using 3-D numerical calculations and low-frequency capacitance measurements.
关键词： Characteristic impedance,propagation constant,deembedding,S-parameters,transmission lines
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Effects of CsF Post-deposition Treatment on Cu(In, Ga)Se <sub/>2</sub> Thin Films and Solar Cells
摘要： This paper proposed a new crossbeam ultrasonic motor, which was made of a cross-shaped metal frame and eight pieces of lead zirconate titanate ceramic plates with a size of 10 mm × 3 mm × 1 mm. Two cross-cone-shaped horns were machined at two ends of the crossbeam, and the tips of the horns served as the driving feet. Ellipse trajectories of the two driving feet were generated by superimposing two orthogonal ?rst bending vibrations with the same resonance frequency but a temporal shift of 90?. A Symmetric structure of the proposed ultrasonic motor solved the problem of mode frequencies degeneracy. A new method to excite these two bending vibrations was proposed. Finite-element method simulation was developed to obtain the vibration characteristics of the crossbeam motor. The new excitation method was compared with the traditional one, and it was found that the vibration amplitudes of the driving feet under the new excitation method were about three times that of the traditional one. At last, experiments were accomplished on a fabricated prototype. The two tested ?rst bending resonance frequencies agreed well with each other at ～40.5 kHz. Mechanical output performance of the prototype was tested; the maximum speed was ～64 r/min, and the maximum output torque was ～10.4 mN · m. This paper provides a new idea for an ultrasonic motor with a miniature structure and also a new excitation method for bending vibration.
关键词： bending vibration,Crossbeam,vibration characteristic.,ultrasonic motor,excitation method
更新于2025-09-19 17:13:59
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[Laser Institute of America ICALEO? 2017: 36th International Congress on Applications of Lasers & Electro-Optics - Atlanta, Georgia, USA (October 22–26, 2017)] International Congress on Applications of Lasers & Electro-Optics - Laser metal deposition with 316L stainless wire: Macro morphologies and microstructures
摘要： Laser metal deposition (LMD) with wire as the filler material has demonstrated to be a potential method in addictive manufacturing due to its higher material deposition efficiency, improved surface quality, reduced material wastage and cleaner process environment without metal dust pollution. In this study, single beads samples and block samples of 316L stainless wire were successfully deposited on the surface of 316L stainless steel under optimized depositing conditions using a YLR-4000 S2 CW Fiber Laser, a Fronius MAG arc welding machine and an ABB industrial robot. The macro morphologies, geometric characteristics and microstructures were examined. The influence of process parameters to macro morphologies and geometric characteristics of different samples were carefully studied. A 5*5 block sample was finally deposited with appropriate parameters based on the single bead experiments. The results showed that satisfied single bead samples with smooth surface and high aspect ratio (height-width ratio) can be deposited under appropriate process conditions and parameters during the stable deposit process. Uniform structures of fine equiaxed austenite grains with good metallurgical bonding to the substrate were also obtained. Uniform bond-like microstructures of block samples was also obtained and investigated. All these results will provide guidance for further large study of laser metal-wire deposition with structures.
关键词： Laser metal deposition,macro morphology,geometric characteristic,316L stainless wire,microstructure
更新于2025-09-16 10:30:52
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Calibration and characteristics of an electrowetting laser scanner
摘要： We present a calibration method to correct for fabrication variations and optical misalignment in a two-dimensional electrowetting scanner. These scanners are an attractive option due to being transmissive, nonmechanical, having a large scan angle (±13.7?), and low power consumption (μW). Fabrication imperfections lead to non-uniform deposition of the dielectric or hydrophobic layer which results in actuation inconsistency of each electrode. To demonstrate our calibration method, we scan a 5 × 5 grid target using a four-electrode electrowetting prism and observe a pincushion type optical distortion in the imaging plane. Zemax optical simulations verify that the symmetric distortion is due to the projection of a radial scanning surface onto a flat imaging plane, while in experiment we observe asymmetrical distortion due to optical misalignment and fabrication imperfections. By adjusting the actuation voltages through an iterative Delaunay triangulation interpolation method, the distortion is corrected and saw an improvement in the mean error across 25 grid points from 43 μm (0.117?) to 10 μm (0.027?).
关键词： Laser scanner,Electrowetting,Scanning characteristic,Calibration
更新于2025-09-16 10:30:52
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Effect of ultrasonic treatment on the properties of multiwalled carbon nanotubes – polymethylmethacrylate composites: Effect of applied voltage and pressure on conductivity of the composites
摘要： The effect of sonication time during the synthesis of multiwalled carbon nanotubes – polymethylmethacrylate (MWCNT/PMMA) composites by coagulation technique on the MWCNT distribution in the bulk of the composites close to the percolation threshold was systematically studied by SEM and by measurements on specific resistivity in a wide range of voltages and external pressure. It was found that the resistivity of composites is irreversibly reduced up to 105 times during the first 1–3 measurements, while further measurements are characterized by high repeatability. Change of the composite resistivity during the measurements is discussed assuming that several types of contacts between the nanotubes changing during the measurement are present. It was found that an increase of the sonication time changed the ratio between ohmic and non-ohmic contacts. It affected the type of changes in the sample resistivity during the voltage variation in the range of 0–103 V/mm and resulted in a nonuniform dependence of the composite specific resistivity on the sonication time. An increase of the composite volume during the resistivity measurements was observed at the current densities above 4·10–8 A/cm2. New ohmic contacts were found to form when external pressure was applied due to squeezing of the polymer matrix from the space between adjacent nanotubes.
关键词： multiwalled carbon nanotube,nanocomposites,contacts between nanotubes,current-voltage characteristic,polymethylmethacrylate
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Zhenjiang, China (2019.8.4-2019.8.8)] 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Design and Modeling of a Decoupled 2-DOF Stick-slip Positioning Stage
摘要： A two degree-of freedom (2-DOF) stick-slip positioning stage is proposed and analyzed. The piezoelectric actuator is developed to realize large stroke positioning based on stick-slip principle. A clamping mechanism is utilized to adjust the normal force at the friction interface, and a hybrid decoupling configuration is adopted to eliminate the cross-coupling error. The working principle is discussed, and finite element analysis is conducted to explore the characteristics of driving unit. In addition, the dynamic model of positioning system based on LuGre friction model is also simulated in Matlab/Simulink. The simulation results indicate that the proposed positioning stage exhibits good dynamic performance.
关键词： positioning stage,characteristic analysis,mechanism design,stick-slip
更新于2025-09-16 10:30:52