- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
A porous Ni-O/Ni/Si photoanode for stable and efficient photoelectrochemical water splitting
摘要： Excellent photoelectrochemical activity was demonstrated for an easily prepared porous Ni-O/Ni/Si photoanode with an onset potential of 0.93 VRHE, a photocurrent of 39.7 mA cm?2 at 1.23 VRHE, an energy conversion efficiency of 3.2% and a stability above 100 h.
关键词： stability,water splitting,porous Ni-O/Ni/Si photoanode,energy conversion efficiency,photoelectrochemical
更新于2025-09-04 15:30:14
-
AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Hydrophilic anti-soiling coating for improved efficiency of solar reflectors
摘要： The reflector is the first key component in the energy conversion process of concentrating solar technologies as any solar radiation that is not reflected by the mirror in the direction of the receiver is lost to the system. Due to the outdoor exposure, solar reflectors are subjected to constant soiling deposition (including dust, sand and/or dirtiness), which severely decreases the output power of the solar concentrating collectors, as it reduces the amount of radiation that can be reflected towards the receiver (associated to the absorption and scattering effects of light). Most of the Concentrating Solar Power (CSP) plants are installed in regions of high Direct Normal Irradiance (DNI) with arid and semi-arid climate, involving the existence of an important amount of dust and sand in the ambient. Collector cleanliness represents one of the most costly expenses of the solar-plant operation and maintenance (O&M). Consequently, minimizing this cost is an important issue for the solar-plant economic feasibility. Anti-soiling coatings deposited on the surface of silvered-glass reflectors are a powerful tool that can help in repelling all sort of dust, sand and particles. This technological solution presents the following benefits: (i) the maintenance cost is driven down by reducing washing times, (ii) the water consumption is drastically diminished and (iii) the efficiency is increased since the average reflectance of the solar field remains higher. This work presents the behavior of a new anti-soiling coating with improved durability and high efficiency.
关键词： durability,anti-soiling coating,solar reflectors,efficiency,hydrophilic
更新于2025-09-04 15:30:14
-
-related Materials
摘要： Dominant recombination paths in AlN and AlxGa1?xN-related structures are investigated using cathodoluminescence (CL) mapping measurements and photoluminescence (PL) spectroscopy. The dark spot contrasts originating from nonradiative recombination at threading dislocations (TDs), which are observed in CL intensity maps, drastically decrease upon elevating the temperature. This is because carriers can reach TDs at low temperatures (9–60 K), but are captured by point defects (PDs) even in the vicinity of TDs near RT. Calculations based on the experimental results indicate that in the current AlN and Al-rich AlxGa1?xN crystals, TDs scarcely affect the internal quantum efficiency (IQE) at RT as long as the TD density is less than 2.6 × 1010 cm?2. Because a TD density less than 2.6 × 1010 cm?2 has already been achieved even for heteroepitaxially grown AlN films on sapphire substrates, it is evident that the most effective method to further improve the IQE of AlxGa1?xN-related materials is to reduce PDs not TDs. Moreover, we clarify the existence of two types of PD states, which mainly degrade the emission efficiency, using temperature-dependent PL measurements. Combining the CL and PL results allows the activation energies of these PDs and TDs to be evaluated. Furthermore, we highlight the probability that PDs, which predominantly act as nonradiative recombination centers at room temperature, are complexes formed by Al vacancies and oxygen impurities that enhance the deep-level emissions at 3.2 and 3.5–3.7 eV near room temperature. Such a large impact of PDs on the efficiency degradation may be attributed to the high density of Al-vacancy–related PDs in AlN and Al-rich AlxGa1?xN compared with that of Ga-vacancy–related PDs in GaN due to the small formation energy.
关键词： AlxGa1?xN,cathodoluminescence,internal quantum efficiency,point defects,photoluminescence,nonradiative recombination,AlN,threading dislocations
更新于2025-09-04 15:30:14
-
[IEEE 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Portland, OR, USA (2018.9.23-2018.9.27)] 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Impact of SiC MOSFET on PV Inverter
摘要： This paper investigates the possibility of improving power density of three-phase grid inverter by adopting SiC MOSFET. Static and dynamic characteristics of trench gate SiC MOSFET, planar gate SiC MOSFET and Si IGBT are compared. The efficiency performance of planar gate SiC MOSFET inverter, trench gate SiC MOSFET inverter and Si IGBT inverter are estimated and compared with increased switching frequency. Finally, these results are verified with 10 kW inverter prototypes.
关键词： trench gate SiC MOSFET,efficiency,planar gate SiC MOSFET,power density,three-phase grid inverter
更新于2025-09-04 15:30:14
-
Efficient 3D low-discrepancy k-space sampling using highly adaptable Seiffert Spirals
摘要： The overall duration of acquiring a Nyquist sampled 3D dataset can be significantly shortened by enhancing the efficiency of k-space sampling. This can be achieved by increasing the coverage of k-space for every trajectory interleave. Further acceleration is possible by making use of advantageous undersampling properties. In this work, a versatile 3D centre-out k-space trajectory, based on Jacobian elliptic functions (Seiffert’s spiral) is presented. The trajectory leads to a low-discrepancy coverage of k-space using a considerably reduced number of read-outs compared to other approaches. Such a coverage is achieved for any number of interleaves and therefore even single-shot trajectories can be constructed to be combined with e.g. hyperpolarized media. Further acceleration is achievable due to non-coherent undersampling properties of the trajectory in combination with non-linear reconstruction techniques like Compressed Sensing (CS). Simulations of point-spread functions and discrepancy evaluations compare Seiffert’s spiral to the established 3D Cones approach. Imaging capabilities are evaluated by comparison of in-vivo knee images using Nyquist and undersampled datasets in combination with CS reconstructions.
关键词： efficiency,trajectory,low-discrepancy,3D,spiral,Compressed Sensing
更新于2025-09-04 15:30:14
-
[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Evaluation of GaN Based Multilevel Converters
摘要： With the significant reduction in board space occupied by the smaller GaN transistors, topologies that require a greater number of active devices as a tradeoff for reduced passive size, the main barrier to higher density, have become attractive. Switched capacitor multilevel converters are good examples of topologies that can effectively reduce or eliminate passive components. Two GaN based proof-of-concept designs (three-level converters), one for a low voltage (LV) 48 V server application and the other for a higher voltage (HV) 400 V power factor correction (PFC) circuit are discussed in this paper. As a result of using lower figure-of-merit (FOM) devices, significant efficiency gains are observed for the LV and HV converters developed in this paper compared to a two-level topology. Smaller passive size (mainly inductors) also provides a significant increase in power density for the LV converter. A startup scheme is discussed which eliminates the need for extraneous control loops or high voltage rated devices for the top switch. Finally, an electrical performance comparison is also shown for a two-stage intermediate bus architecture (IBA) developed with the GaN based three-level converter for the front end and a high frequency GaN-based second buck stage for 48 V to 1 V point-of-load (PoL) conversion. Two choices of intermediate bus voltage are investigated: 12 V and 6 V. Each bus voltage demonstrates its advantage in a certain range of load current.
关键词： efficiency,DC-DC converter,GaN,Startup,power density,IBC,Multilevel
更新于2025-09-04 15:30:14
-
A study of the impact of VLC on the quality of lighting and display – EPSRC
摘要： Dr Wasiu Popoola of the University of Edinburgh talks about his research into visible light communication and shares the results of his latest work examining the underutilised optical spectrum as a potential pathway to wirelessly connect devices. The research investigates the impacts of visible light communication (VLC) on the fundamental properties of energy efficiency, light quality and life expectancy of a light-emitting diode (LED) that is primarily designed for lighting or display. It aims to deliver the required approach for optimising VLC and safeguard the LED’s reliability, durability and emitted light quality.
关键词： light quality,LED,VLC,energy efficiency,visible light communication,life expectancy
更新于2025-09-04 15:30:14
-
New Analytical Formulae to Calibrate Well-type Scintillation Detectors Efficiency
摘要： Direct Mathematical calculations for the absolute efficiency of well-type gamma ray scintillation crystals are described. Calculated detection efficiencies are drawn for two commonly used well crystals. Comparisons are made between present works and published Monte Carlo values. The present approach proved quite success in predicting the efficiency of well type detectors providing only the geometry and materials of the system formed of source, detector and shielding as well as the energy of the emitted photons.
关键词： Absolute efficiency,Well-type detector,Gamma-spectroscopy,New mathematical method
更新于2025-09-04 15:30:14