- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Selection of Commercial-Off-the-Shelf Antistatic Coating and Its Applicability for Space-Use Solar Arrays
摘要： In recent years, the power generation requirement of spacecrafts has increased in order to load them with many mission devices and to extend their lifetime, hence, high voltages are used. However, such high voltages can cause electrostatic discharges on solar arrays, resulting in damage to the solar arrays. Therefore, we use an antistatic coating, which mitigates the surface charging on solar cells, in order to prevent the discharge. It is considered that an antistatic coating can mitigate surface charging and can prevent discharges on solar cells. The purpose of this research is to develop a coating to mitigate the surface charging applicable to geostationary Earth orbit satellites. We selected a candidate coating with the required surface resistivity and vacuum resistance. Furthermore, we selected a commercial-off-the-shelf antistatic coating after considering the experimental results of charging mitigation performance when simulating the charging condition in space. The candidate agent was coated on a conventional solar array coupon panel, and the charging mitigation performance of the latter was evaluated. We have confirmed a dramatic improvement in charging mitigation performance with this coated conventional solar array coupon.
关键词： Commercial-Off-the-Shelf,Antistatic Coating,Electrostatic Charging and Discharging,Solar Array
更新于2025-09-19 17:15:36
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Efficient blue organic light-emitting diodes with low operation voltage by improving the injection and transport of holes
摘要： In this work, we reported the highly efficient organic electroluminescent (EL) devices based on blue phosphorescent material FIr6. By utilizing p-type dopant HAT-CN as hole injection layer material, the injection of holes from the anode was significantly improved. In addition, doping HAT-CN into hole transport layer (HTL) and inserting thin TcTa film between HTL and light-emitting layer (EML) improved the transport of holes. The stepwise energy levels between functional layers reduced the injection barriers of carriers, thus improving the balance of carriers within EML. Finally, highly efficient blue EL device realized the maximum current efficiency, power efficiency, external quantum efficiency (EQE) and brightness up to 39.14 cd/A, 38.68 lm/W, 24.6% and 17201 cd/m2, respectively. Even at the high brightness of 1000 cd/m2 (3.7 V), current efficiency and EQE as high as 36.73 cd/A and 23.1%, respectively, can still be retained by the same device. Our investigation provides an idea for the design of high-performance devices with low operation voltage and slow efficiency roll-off.
关键词： Electroluminescence,Operation voltage,Efficiency roll-off,p-type dopant
更新于2025-09-19 17:13:59
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Performance analysis of GaN-based micro light-emitting diodes by laser lift-off process
摘要： In this study, a monochromatic GaN-based micro-light-emitting-diode (μLED) array was fabricated using flip-chip technology. The laser lift-off (LLO) process was employed to decrease the light divergence caused by the differing refractive indexes of sapphire (n = 1.77) and GaN (n = 2.4). The LLO-μLEDs considerably improve light collimation, compared with conventional flip-chip μLEDs containing a sapphire substrate. We highlight, in particular, the importance of the optical characteristics before and after LLO. Collimation of light was discovered to be 12% higher after removal of the sapphire substrate. The results are of high importance for understanding the optical properties of μLED arrays after LLO.
关键词： Light-emitting diodes,Micro-LEDs,Laser lift-off,GaN
更新于2025-09-19 17:13:59
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Self-powered, all-solution processed, trilayer heterojunction perovskite-based photodetectors
摘要： Heterostructures composed of nano-/micro-junctions, combining the excellent photon harvesting properties of nano-system and ultrafast carrier transfer of micro-system, have shown promising role in high-performance photodetectors. Here, in this paper a highly-sensitive trilayer in which the CdS nanorods (NRs) layer is sandwiched between ZnO/CsPbBr3 interface to reduce self-powered perovskite-based photodetector ITO/ZnO(70nm)/CdS(150nm)/CsPbBr3(200nm)/Au, ratio of 106 with a responsivity of 86 mA/W and a specific detectivity of 6.2×1011 Jones was obtained at zero bias under 85 μW/cm2 405 nm illumination, and its rise/decay time at zero bias is to the strong built-in potential and the internal driving electric-field, an ultra-high On/Off current 0.3/0.25 s. Therefore, the enhanced device performance strongly suggest the great potential of such the interfacial charge carriers’ recombination and the charge transport resistance, is presented. Due a kind of trilayer heterojunction devices for high-performance perovskite photodetectors.
关键词： On/Off current ratio,CdS nanorods (NRs) layer,trilayer heterojunction,specific detectivity,gradient energy alignment,Self-powered photodetector,high-performance
更新于2025-09-19 17:13:59
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[IEEE 2019 4th International Conference on Mechanical, Control and Computer Engineering (ICMCCE) - Hohhot, China (2019.10.24-2019.10.26)] 2019 4th International Conference on Mechanical, Control and Computer Engineering (ICMCCE) - Laser Molten Pool Temperature Detecting Based on Recursive Estimation in 3D Printing
摘要： Free-space optical communication links operating over lognormal turbulence channels using on-off keying (OOK) are studied in this paper. Such systems can suffer from irreducible error floors that result from the use of demodulation with fixed and unoptimized detection thresholds. The resulting error floors are analyzed for the general case of low- and high-state offsets (i.e., finite extinction ratios). An electrical signal-to-noise ratio (SNR) optimized detection system is applied. The system uses the electrical SNRs to implement adaptive detection thresholds and eliminate the error floors. The system can accommodate operation with finite extinction ratios, as it uses the method of moments and maximum likelihhod estimation techniques to estimate the low- and high-state offsets and electrical SNR. Numerical results show that the SNR gap between the electrical-SNR-optimized detection system and the adaptive detection system is 2.3 dB at a bit-error rate of 10?5 without a state offset. The SNR gap increases to 4.5 dB with a state offset of ξ = 0.2.
关键词： Atmospheric turbulence,FSO,on-off keying,optical wireless communications
更新于2025-09-19 17:13:59
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Toward Long-Distance Underwater Wireless Optical Communication Based on A High-Sensitivity Single Photon Avalanche Diode
摘要： In this study, we built a single photon avalanche diode (SPAD) receiver based underwater wireless optical communication (UWOC) system. The bit error rate (BER) and signal-to-noise ratio (SNR) performance of UWOC with different distances and data transmission rates were obtained. Based on the water attenuation coefficient of 0.12 m-1, a series of neutral density (ND) filters were exploited to attenuate the light output power from the blue laser diode (LD) to simulate the long distance UWOC. The maximum estimated distances of 144 m and 117 m with corresponding BERs of 1.89 × 10-3 and 5.31 × 10-4 at data transmission rates of 500 bps and 2 Mbps were acquired in UWOC system using on-off keying (OOK) modulation scheme, respectively. Furthermore, we compared the differences between free-space and underwater channels, and a divergence angle of ~1.02 mrad was measured experimentally at a distance of 50 m in the free space. The long UWOC distances obtained in this study partly benefit from high sensitivity SPAD, the small laser divergence angle and low light attenuation. This study provides an approach to achieve long distance UWOC using SPAD.
关键词： laser,on-off keying,single photon avalanche diode (SPAD),Underwater wireless optical communication (UWOC)
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE Regional Symposium on Micro and Nanoelectronics (RSM) - Genting Highland, Pahang, Malaysia (2019.8.21-2019.8.23)] 2019 IEEE Regional Symposium on Micro and Nanoelectronics (RSM) - Simulation and Optimization of Emitter Thickness for Indium Arsenide-Based Thermophotovoltaic Cell
摘要： Free-space optical communication links operating over lognormal turbulence channels using on-off keying (OOK) are studied in this paper. Such systems can suffer from irreducible error floors that result from the use of demodulation with fixed and unoptimized detection thresholds. The resulting error floors are analyzed for the general case of low- and high-state offsets (i.e., finite extinction ratios). An electrical signal-to-noise ratio (SNR) optimized detection system is applied. The system uses the electrical SNRs to implement adaptive detection thresholds and eliminate the error floors. The system can accommodate operation with finite extinction ratios, as it uses the method of moments and maximum likelihood estimation techniques to estimate the low- and high-state offsets and electrical SNR. Numerical results show that the SNR gap between the electrical-SNR-optimized detection system and the adaptive detection system is 2.3 dB at a bit-error rate of 10?5 without a state offset. The SNR gap increases to 4.5 dB with a state offset of ξ = 0.2.
关键词： Atmospheric turbulence,FSO,on-off keying,optical wireless communications
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE BiCMOS and Compound semiconductor Integrated Circuits and Technology Symposium (BCICTS) - Nashville, TN, USA (2019.11.3-2019.11.6)] 2019 IEEE BiCMOS and Compound semiconductor Integrated Circuits and Technology Symposium (BCICTS) - Integrated CMOS-Compatible Mode-Locked Lasers and Their Optoelectronic Applications
摘要： Free-space optical communication links operating over lognormal turbulence channels using on-off keying (OOK) are studied in this paper. Such systems can suffer from irreducible error floors that result from the use of demodulation with fixed and unoptimized detection thresholds. The resulting error floors are analyzed for the general case of low- and high-state offsets (i.e., finite extinction ratios). An electrical signal-to-noise ratio (SNR) optimized detection system is applied. The system uses the electrical SNRs to implement adaptive detection thresholds and eliminate the error floors. The system can accommodate operation with finite extinction ratios, as it uses the method of moments and maximum likelihhod estimation techniques to estimate the low- and high-state offsets and electrical SNR. Numerical results show that the SNR gap between the electrical-SNR-optimized detection system and the adaptive detection system is 2.3 dB at a bit-error rate of 10?5 without a state offset. The SNR gap increases to 4.5 dB with a state offset of ξ = 0.2.
关键词： Atmospheric turbulence,FSO,on-off keying,optical wireless communications
更新于2025-09-19 17:13:59
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[IEEE 2019 Systems of Signal Synchronization, Generating and Processing in Telecommunications (SYNCHROINFO) - Russia (2019.7.1-2019.7.3)] 2019 Systems of Signal Synchronization, Generating and Processing in Telecommunications (SYNCHROINFO) - Experimental Researches of the Macrobend Effect of Optical Fibers on Brillouin Traces
摘要： The network densi?cation of small cells (SCs) is a promising way to cope with the explosive growth of future traf?c demands in 5G networks. However, the overall power consumption and the backhaul limitation of the network have become the key factors affecting the network performance and users’ quality-of-experience, which have great importance in 5G wireless networks. Due to the complexity of 5G networks and the variety of user behaviors, the combination of software-de?ned networks and content delivery strategy could be a more ef?cient way to manage such networks. In this paper, a cache-enabled wireless heterogeneous network with the control-plane (C-plane) and user-plane (U -plane) split is proposed, where the macro cell and SCs with different cache abilities are overlaid and cooperated together in the backhaul scenario. Using an evaluation tool composed of stochastic processes and classical power consumption model, key performance indicators, e.g., the coverage probability, throughput, and energy ef?ciency (EE), are derived as closed-form expressions or the functions of the signal-to-interference-plus-noise ratio threshold, path loss exponent, transmission power and density of macro and SCs, cache ability, ?le popularity, and backhaul capacity. Fundamental trade-offs are illustrated between EE and transmission power, EE and SC density, as well as the throughput and density of SCs. Numerical results show that the proposed cache-enabled software-de?ned networks have much higher throughput and improved EE than current LTE networks, which shows a promising solution for future cellular networks.
关键词： software defined networks,green communications,coverage probability,trade-off,Cache-enabled networks,spectral and energy efficiency
更新于2025-09-19 17:13:59
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Facile synthesis, structure analysis and optical performance of manganese oxide-doped PVA nanocomposite for optoelectronic and optical cut-off laser devices
摘要： In the present work, successful manganese oxide (Mn2O3) nanoparticles (NPs) were synthesized by a combustion technique, while the casting process was employed for the manufacturing of polymer nanocomposites with various weights of Mn2O3 based on Poly(Vinyl Alcohol), PVA. Multiple methods such as X-ray diffraction (XRD), HR-TEM, EDAX, EDS, SEM, FT-IR, DTA analysis, optical spectroscopy from UV to IR regions, and optical reduction (CUT-OFF) setup were used to characterize the structural, elemental chemical analysis, morphological, optical properties, and cut-off laser characteristic of nanocomposite samples. Mn2O3 nanoparticles have a crystallite size of 22.08 nm as calculated using the Debye–Scherer formula from XRD, while the HR-TEM shows a spherical particle of size 30–38 nm range. EDAX spectra and EDS mapping were used to detect the elemental particles of the nanocomposite. The external morphology of the films by SEM images shows an increase in the agglomeration size of the cluster with the percentage of Mn2O3 nanoparticles in PVA. FT-IR spectra show excellent incorporation between the matrix of polymer and the Mn2O3 via the hydroxyl group. Moreover, with increasing the doping rate of nanoparticles, the thermal stability of PVA increased. A significant change of optical transmittance, absorption edge, Urbach energy, and transition bandgap have been observed due to the influence of Mn2O3. The comparison between the bandgap values that have been estimated from Tauc’s relation and thus resulting from optical dielectric loss indicates a direct allowed transition of electrons in the nanocomposites. The light is entirely UV–Vis absorbed by PVA with a high percentage of Mn2O3 nanoparticles. Moreover, the efficiency of the films to decrease the power of two laser beams (635 nm and 533 nm) has been observed. The flexible films of PVA with an elevated rate of Mn2O3 are considered a successful option for low-cost technologies of optical limiting.
关键词： Casting process,Combustion technique,PVA nanocomposite,Optoelectronic,Manganese oxide,Optical cut-off laser devices
更新于2025-09-19 17:13:59