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[IEEE 2018 12th France-Japan and 10th Europe-Asia Congress on Mechatronics - Tsu, Japan (2018.9.10-2018.9.12)] 2018 12th France-Japan and 10th Europe-Asia Congress on Mechatronics - Potentials of Galilean and Keplerian Liquid Crystal Zoom Lens System
摘要： This paper focuses on a non-mechanical zoom lens system using Liquid Crystal (LC). The LC lens cell is well known as an optical device of which the focal length can change non-mechanically as a lens by small electric power. The authors apply the two LC lens cells for composing the zoom lens system in which the magnification can change continuously in this paper. As two representative types of the telescopic lens, the Keplerian and the Galilean are famous. The former combines two convex lenses, while the latter combines a convex lens and a concave lens. The range of the focal length of which the LC lens cell can change is definite. It depends on the lens power, which is defined as an inverted value of the focal length. In this study, potential performances of the magnification range as the zoom lens, from the minimum to the maximum, have been estimated by simulation, comparing between the Keplerian and Galilean types. In addition, requirements of the lens power of the LC lens has been estimated. The authors have also discussed their smallest realizable size of the LC zoom lens system from the above simulation results.
关键词： Keplerian,the smallest size,potential performance,non-mechanical zoom lens,Galilean,liquid crystal zoom lens
更新于2025-09-23 15:21:01
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Nanoscale charge transport and local surface potential distribution to probe defect passivation in Ag doped Cu2ZnSnS4 absorbing layer
摘要： The performance of earth abundant Cu2ZnSnS4 (CZTS) material is limited by high deficit of open circuit voltage (VOC) which is mainly due to the easy formation of CuZn antisite defects. Suppression of CuZn defects is thus inevitably required for further developments in CZTS based solar cells. We studied systematic increase of Ag doping in CZTS thin film and investigated the nanoscale electrical properties using kelvin probe force microscopy (KPFM) and current sensing atomic force microscopy (CAFM) to probe CuZn defects. Crystallographic analysis indicated the successful partial substitution of Cu+ ions by large size Ag+ ions. The considerable decrease in grain boundary potential from 66.50 ± 5.44 mV to 13.50 ± 2.61 mV with Ag doping, suggesting the substantial decrease in CuZn defects. Consequently, CAFM measurement confirms the remarkable increment in minority carrier current with Ag doping and their local mobility in CZTS layer. Finally, the lower persistent photoconductivity (PPC) and fast decay response of photogenerated carriers for Ag doped CZTS photodetector further validate our results. This study provides a fresh approach of controlling deleterious CuZn defects in CZTS by tuning Ag content that may guide researchers to develop next generation high performance CZTS based solar cells.
关键词： nanoscale surface potential and current,CZTS solar cells,Ag doped CZTS,defects,photodetector
更新于2025-09-23 15:21:01
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Effect of hydrogen-like impurity on a qubit in quantum pseudodot at finite temperature
摘要： In?uences of temperature on the qubit's properties in a quantum pseudodot (QPD) are studied by using the variational method of Pekar type (VMPT) and quantum statistics theory (QST). The formation of qubit requires two special conditions: One is the strong-coupling between the electron and the bulk longitudinal optical (LO) phonon, and the other is the hydrogen-like impurity (HLI) locating at the center of the QPD. So, we choose strong-coupling RbCl crystal as an example and calculate the electron probability density (EPD) and the oscillating period (OP) of the QPD qubit changing with the temperature and the Coulombic impurity potential (CIP).
关键词： Coulomb impurity potential,Oscillation period,Quantum pseudo dot,Qubit probability density
更新于2025-09-23 15:21:01
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Transport in a thin topological insulator with potential and magnetic barriers
摘要： We study transport across either a potential or a magnetic barrier which is placed on the top surface of a three-dimensional thin topological insulator (TI). For such thin TIs, the top and bottom surfaces interact via a coupling λ which influences the transport properties of junctions constructed out of them. We find that for junctions hosting a potential barrier, the differential conductance oscillates with the barrier strength. The period of these oscillations doubles as the coupling λ changes from small values to a value close to the energy of the incident electrons. In contrast, for junctions with a magnetic barrier, the conductance approaches a nonzero constant as the barrier strength is increased. This feature is in contrast to the case of transport across a single TI surface where the conductance approaches zero as the strength of a magnetic barrier is increased. We also study the spin currents for these two kinds of barriers; in both cases, the spin current is found to have opposite signs on the top and bottom surfaces. Thus this system can be used to split applied charge currents to spin currents with opposite spin orientations which can be collected by applying opposite spin-polarized leads to the two surfaces. We show that several of these features of transport across finite width barriers can be understood analytically by studying the δ-function barrier limit. We discuss experiments which may test our theory.
关键词： magnetic barrier,transport,spin current,potential barrier,topological insulator
更新于2025-09-23 15:21:01
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The Influence of the EVA Film Aging on the Degradation Behavior of PV Modules Under High Voltage Bias in Wet Conditions Followed by Electroluminescence
摘要： The influence of the ethylene-vinyl acetate (EVA) film quality on potential induced degradation was studied on in-house developed mini modules with p-type monocrystalline silicon solar cells. The modules were assembled with EVA films of equivalent qualities, but different ages and exposed to an accelerated test (relative humidity = 85%, T = 60 °C, Vbias = +1000 V). The age of the EVA film was determined from the time we received the EVA film, and opened the sealed enclosure and the time of lamination. After the EVA film was removed from the sealed enclosure, it was kept in a dark place at room temperature. The storage times of the “fresh,” “aged,” and “expired” films were: less than 14 d, around 5 mo, and more than 5 years, respectively. While modules with a “fresh” EVA film exhibit almost no degradation, the modules with the “aged” EVA film degrade very rapidly and severely. Their degradation rate was around 0.2%/d during the 2000 h of damp heat test. We also observed a strong silver line corrosion, which occurs because of the peroxide leftovers in the “aged” EVA films.
关键词： photovoltaic (PV) modules,high voltage stress,EVA film,Degradation,potential induced degradation (PID),leakage current
更新于2025-09-23 15:21:01
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Nanoscale virtual potentials using optical tweezers
摘要： We combine optical tweezers with feedback to impose arbitrary potentials on a colloidal particle. The feedback trap detects a particle’s position, calculates a force based on an imposed “virtual potential,” and shifts the trap center to generate the desired force. We create virtual harmonic and double-well potentials to manipulate particles. The harmonic potentials can be chosen to be either weaker or stiffer than the underlying optical trap. Using this ?exibility, we create an isotropic trap in three dimensions. Finally, we show that we can create a virtual double-well potential with ?xed well separation and adjustable barrier height. These are accomplished at length scales down to 11 nm, a feat that is dif?cult or impossible to create with standard optical-tweezer techniques such as time sharing, dual beams, or spatial light modulators.
关键词： optical tweezers,colloidal particle,virtual potential,nanoscale,feedback trap
更新于2025-09-23 15:21:01
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Enhancement for Potential-Induced Degradation Resistance of Crystalline Silicon Solar Cells via Anti-Reflection Coating by Industrial PECVD Methods
摘要： The issue of potential-induced degradation (PID) has gained more concerns due to causing the catastrophic failures in photovoltaic (PV) modules. One of the approaches to diminish PID is to modify the anti-re?ection coating (ARC) layer upon the front surface of crystalline silicon solar cells. Here, we focus on the modi?cation of ARC ?lms to realize PID-free step-by-step through three delicate experiments. Firstly, the ARC ?lms deposited by direct plasma enhanced chemical vapor deposition (PECVD) and by indirect PECVD were investigated. The results showed that the ef?ciency degradation of solar cells by indirect PECVD method is up to ?33.82%, which is out of the IEC 62804 standard and is signi?cantly more severe than by the direct PECVD method (?0.82%). Next, the performance of PID-resist for the solar cell via indirect PECVD was improved signi?cantly (PID reduced from ?31.82% to ?2.79%) by a pre-oxidation step, which not only meets the standard but also has higher throughput than direct PECVD. Lastly, we applied a novel PECVD technology, called the pulsed-plasma (PP) PECVD method, to deal with the PID issue. The results of the HF-etching rate test and FTIR measurement indicated the ?lms deposited by PP PECVD have higher potential against PID in consideration of less oxygen content in this ?lm. That demonstrated the ?lm properties were changed by applied a new control of freedom, i.e., PP method. In addition, the 96 h PID result of the integrated PP method was only ?2.07%, which was comparable to that of the integrated traditional CP method. In summary, we proposed three effective or potential approaches to eliminate the PID issue, and all approaches satis?ed the IEC 62804 standard of less than 5% power loss in PV modules.
关键词： solar cell,potential-induced degradation,anti-re?ection coating,plasma enhanced chemical vapor deposition
更新于2025-09-23 15:21:01
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Optical Recording of Action Potential Initiation and Propagation in Mouse Skeletal Muscle Fibers
摘要： Skeletal muscle ?bers have been used to examine a variety of cellular functions and pathologies. Among other parameters, skeletal muscle action potential (AP) propagation has been measured to assess the integrity and function of skeletal muscle. In this work, we utilize 1-(3-sulfonatopropyl)-4[b[2-(Di-n-octylamino)-6-naphtyl]vinyl]pyridinium betaine, a potentiometric dye, and mag-?uo-4, a low-af?nity intracellular Ca2tindicator, to noninvasively and reliably measure AP conduction velocity in skeletal muscle. We used remote extracellular bipolar electrodes to generate an alternating polarity electric ?eld that initiates an AP at either end of the ?ber. Using enzymatically dissociated ?exor digitorum brevis (FDB) ?bers and high-speed line scans, we determine the conduction velocity to be (cid:2)0.4 m/s. We applied these methodologies to FDB ?bers under elevated extracellular potassium conditions and con?rmed that the conduction velocity is signi?cantly reduced in elevated [Kt]o. Because our recorded velocities for FDB ?bers were much slower than previously reported for other muscle groups, we compared the conduction velocity in FDB ?bers to that of extensor digitorum longus (EDL) ?bers and measured a signi?cantly faster velocity in EDL ?bers than FDB ?bers. As a basis for this difference in conduction velocity, we found a similarly higher level of expression of Nat channels in EDL than in FDB ?bers. In addition to measuring the conduction velocity, we can also measure the passive electrotonic potentials elicited by pulses by applying tetrodotoxin and have constructed a circuit model of a skeletal muscle ?ber to predict passive polarization of the ?ber by the ?eld stimuli. Our predictions from the model ?ber closely resemble the recordings acquired from in vitro assays. With these techniques, we can examine how various pathologies and mutations affect skeletal muscle AP propagation. Our work demonstrates the utility of using 1-(3-sulfonatopropyl)-4[b[2-(Di-n-octylamino)-6-naphtyl]vinyl]pyridinium betaine or mag-?uo-4 to noninvasively measure AP initiation and conduction.
关键词： potentiometric dye,action potential,Nat channels,skeletal muscle,Ca2t indicator,conduction velocity,electric ?eld stimulation
更新于2025-09-23 15:21:01
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Formation of Quantum Vortices at the Ionization of an Atom by an Ultrashort Laser Pulse: Two- and Three-Dimensional Cases
摘要： Quantum vortices formed at the barrier-suppression ionization of an atom by an ultrashort laser pulse have been studied theoretically and numerically. The ionization of a hydrogen atom is considered in the two-dimensional space and the ionization of an atom in the zero-range potential approximation is considered in the three-dimensional space. The resulting analytical expressions imply that the localization of quantum vortices in the three-dimensional space can be predicted by analyzing the two-dimensional model.
关键词： hydrogen atom,zero-range potential approximation,ultrashort laser pulse,Quantum vortices,barrier-suppression ionization
更新于2025-09-23 15:19:57
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Influence of WSe2 buffer layer at back electrode on performance of Cu2ZnSn(S,Se)4 solar cells
摘要： CZTSSe-based solar cells with a structure of Al/ITO/ZnO/CdS/CZTSSe/p-WSe2/Mo (denoted as WSe2-CZTSSe solar cell) were prepared on the Mo-coated soda-lime glass (SLG) with a pre-sputtering metal tungsten (W) layer. Comparing with the conventional CZTSSe solar cell with a structure of Al/ITO/ZnO/CdS/CZTSSe/n-MoSe2/Mo (denoted as CZTSSe solar cell), the WSe2-CZTSSe solar cell shows a significant improvement in open-circuit voltage (VOC), short-circuit current density (JSC) and fill factor (FF), and so its power conversion efficiency (PCE) enhances. The largest enhancement of the PCE is from 4.13% of the CZTSSe solar cell to 5.45% of the WSe2-CZTSSe solar cell. The increased VOC and JSC are mainly due to the enhancement of photogenerated current density (JL) and decrease of reversion saturation current density (J0), while the increased FF is ascribed to the increase of shunt resistance (RSh). The influence mechanism of the WSe2 buffer layer on JL, J0 and RSh is also investigated in detail. Our results present a route of increment of PCE by reducing and even removing back contact barrier between CZTSSe and MoSe2 layers.
关键词： Cu2ZnSn(S,Se)4,Solar cell,MoSe2,Contact potential barrier,Interface,WSe2
更新于2025-09-23 15:19:57