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- 摘要
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- 实验方案
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The role of photovoltaics in a sustainable European energy system under variable CO <sub/>2</sub> emissions targets, transmission capacities, and costs assumptions
摘要： PyPSA-Eur-Sec-30 is an open-source, hourly resolved, networked model of the European energy system that includes one node per country as well as electricity, heating, and transport sectors. The capacity and dispatch of generation and storage technologies in every country can be cost optimized under different CO2 emissions constraints. This paper presents an overview of the most relevant results previously obtained with the model, highlighting the influence of solar photovoltaic (PV) generation on them. For 95% CO2 emissions reduction, relative to 1990 level, PV generation supplies in average 33% of the electricity demand. Southern European countries install large PV capacities together with electric batteries, while northern countries install onshore and offshore wind capacities and use hydrogen storage and reinforced interconnections to deal with wind fluctuations. The strong daily generation profile of solar PV heavily impacts the dispatch time series of backup generation and storage technologies. The optimal PV and wind capacities are investigated for variable CO2 emissions, transmission interconnection among neighbouring countries, and cost assumptions.
关键词： energy system modelling,CO2 emissions targets,sector coupling,storage,grid integration,transmission grid
更新于2025-09-12 10:27:22
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Proton generation from hydrocarbon polymer targets for laser ion source
摘要： A laser ion source can provide intense pulsed ion beams from a solid target. On the other hand, generation of a proton beam with a laser ion source requires using compound targets containing hydrogen. In this research, we demonstrated proton generation from three kinds of hydrocarbon polymer targets: polyethylene (C2H4)n, polypropylene (C3H6)n, and polystyrene (C8H8)n. The laser used was a Nd:YAG laser (532 nm/17 ns), and the energy was 0.2 J. The ion current and the fraction of ion species were measured using a Faraday cup and an electrostatic ion analyzer. The results indicated that the peak currents and fraction to total particle number of proton were similar for the different hydrocarbon polymer targets and also showed that increasing the laser intensity effectively increases the number of proton particles because the larger the laser intensity, the larger the total charge.
关键词： hydrocarbon polymer targets,Nd:YAG laser,proton generation,electrostatic ion analyzer,ion current,laser ion source
更新于2025-09-12 10:27:22
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Improving the quality of proton beams via double targets driven by an intense circularly polarized laser pulse
摘要： A new scheme is proposed to improve the quality of proton beams via ultra-intense laser pulse interacting with double plasma targets, which consist of a pre-target with relatively low density and a main target with high density. Both one- and two-dimensional Particle-in-Cell simulations show that, the using of an appropriate pre-target can help to obtain a much stronger longitudinal charge separation field in contrast to using only the main target. And proton beam with lower momentum divergence, better monochromaticity and collimation, as well as higher current density is generated. Moreover, due to the strengthened coupling between the laser pulse and targets, the energy conversion from laser pulse to protons is also increased.
关键词： proton beams,charge separation field,Particle-in-Cell simulations,circularly polarized laser pulse,double targets
更新于2025-09-12 10:27:22
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Fabrication of in-situ Ti-doped CuGaS2 thin films for intermediate band solar cell applications by sputtering with CuGaS2:Ti targets
摘要： Intermediate band solar cells (IBSCs) have great potential for improving device efficiencies, which can be fabricated by doping appropriate elements into a matrix semiconductor with a high band-gap (Eg). CuGaS2 (CGS) is an absorber with high absorption coefficient and high Eg, which is suitable to be a matrix. And some transition metals are suitable doping elements. Here, in-situ Ti-doped CGS thin films were deposited by sputtering CuGaS2:Ti targets to prepare IBSCs. The targets were fabricated by hot-pressed sintering of ball-milled Cu2S, Ga2S3, and TiS2 mixed powders. In-situ Ti-doped precursor films were prepared by sputtering with these targets. After sulfurization, grains grew up and CGS phases were gained. The Ti atoms were successfully doped into the CGS lattices. The Eg of about 2.42 eV was consistent with CGS. The current density-voltage curve of the solar cell exhibited exponential characteristics. This approach has enormous promise for the preparation of IBSCs.
关键词： In-situ doping,Intermediate band solar cells,CuGaS2:Ti targets,Sputtering,Solar energy materials
更新于2025-09-11 14:15:04
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Signal Penetration of Low SAR Frequency Over Three Compact Polarimetric Modes
摘要： Compact polarimetry has the ability of reducing the complexity, cost, mass, and data rate of a SAR system while attempting to obtain many capabilities of quad polarisation systems. In this paper, we investigate the penetration of P-band signal and polarimetric degradation for the three compact polarimetric modes using two triangular trihedral corner reflectors, where one is immersed in the trees, and the other is outside the trees. The results from the π/4 mode showed a reduction of 0.6dB in the H channel while it was 2.28dB in the V channel. Also, the DCP mode showed a zero phase difference for the reflector outside the trees, while a 64.66? phase difference showed for the reflector immersed in the trees. Moreover, the reduction of signal was -30.4dB in the H channel, and it was 2.36dB in the V channel. Finally, the CRLT mode showed a similar signal reduction as the π/4 mode but the polarimetric degradation for the reflector immersed in the trees was 64.66?.
关键词： Synthetic Aperture Radar,Compact Polarimetry,Passive Point Targets,Radar Polarimetry
更新于2025-09-10 09:29:36
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Economic and environmental potential for solar assisted central heating plants in the EU residential sector: Contribution to the 2030 climate and energy EU agenda
摘要： Aligning with the ambitious EU 2030 climate and energy package for cutting the greenhouse emissions and replacing conventional heat sources through the presence of renewable energy share inside efficient district heating fields, central solar heating plants coupled with seasonal storage (CSHPSS) can have a viable contribution to this goal. However, the technical performance variation combined with inadequate financial assessment and insufficient environmental impact data associated with the deployment of those innovative district heating systems represents a big challenge for the broad implementation of CSHPSS in Europe. In this context, our paper presents a comprehensive evaluation for the possibility of integrating CSHPSS in the residential sector in various EU member states through the formulation of a multi-objective optimization framework. This framework comprises the life cycle cost analysis for the economic evaluation and the life cycle assessment for the environmental impact estimation simultaneously. The technical performance is also considered by satisfying both the space heating demand and the domestic hot water services. The methodological framework is applied to a residential neighborhood community of 1120 apartments in various EU climate zones with Madrid, Athens, Berlin, and Helsinki acting as a proxy for the Mediterranean continental, Mediterranean, central European, and Nordic climates, respectively. The optimization results regarding the energy performance show that the CSHPSS can achieve a renewable energy fraction above 90% for the investigated climate zones. At the same time, the environmental assessment shows significant improvement when using the CSHPSS in comparison to a natural gas heating system, in those cases the environmental impact is reduced up to 82.1–86.5%. On the other hand, substantial economic improvement is limited, especially in the Mediterranean climate zone (Athens) due to low heating demands and the prices of the non-renewable resources. There the total economic cost of the CSHPSS plants can increase up to 50.8% compared to a natural gas heating system. However, considering the incremental tendency in natural gas prices all over EU nowadays, the study of future plant costs confirms its favorable long-term economic feasibility.
关键词： Life cycle assessment (LCA),2030 climate and energy EU targets,Multi-objective optimization,Life cycle cost (LCC),Central solar heating plant with seasonal storage,Solar community
更新于2025-09-10 09:29:36
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Through-Wall Detection of the Moving Paths and Vital Signs of Human Beings
摘要： Detection of human activities in complex environments such as through wall by ultrawideband radar has many important applications in security, vital rescue, and so on. It is much more dif?cult to detect vital signs of moving human beings than static ones. In this letter, we build a model for moving targets and apply the time domain ?nite element method to simulate single-input multiple-outputs (SIMO) radar data. Human respiration is modeled by changing body size and physical parameters. The background removal is performed for radar data. Then, we use the back projection to reconstruct the consecutive target locations, which constitute the moving path, leading to a curve carrying vital signs in the radar image. Since SIMO radar data are multivariate, we use multivariate empirical mode decomposition (MEMD) and fast Fourier transform to separate and extract the respiratory characteristic frequencies. The reconstructed frequency coincides with that in the original model. The result shows that the combination of SIMO radar and MEMD can effectively identify the moving path of the human being behind the wall and extract vital signs.
关键词： time domain ?nite element method (TDFEM),ultrawideband (UWB) single-input multiple-outputs (SIMO) radar,Moving targets,through-wall detection,vital signs
更新于2025-09-09 09:28:46
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[IEEE 2018 19th International Radar Symposium (IRS) - Bonn, Germany (2018.6.20-2018.6.22)] 2018 19th International Radar Symposium (IRS) - Polarization Scattering Matrix Estimation for Moving Targets using Measurement Selection
摘要： In this paper, we deal with the problem of polarization scattering matrix (PSM) estimation for moving targets. To this end, we first formulate the measurement model for time-sharing polarimetric radar, and then jointly examine the influence of target motion on the scattering matrix estimation. For estimation purposes, we assume the target is deterministic during the coherent processing interval (CPI). Thus, there is a set of observation data with the same scattering matrix. As the performance of pulse integration (PI) declines when the target is in motion, we derive a method using optimal selection (OS) to estimate the moving target PSM. Compared with the PI, the proposed method shows excellent performance, and numerical results verify its validity.
关键词： pulse integration,polarization scattering matrix,moving targets,time-sharing polarimetric radar,optimal selection
更新于2025-09-09 09:28:46
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Experimental study of proton acceleration from thin-foil on a table top Ti:Sapphire
摘要： Table-top lasers of moderate energies (0.1- 0.5 J) are promising, cost-effective laser-driven sources of MeV-energy protons and ions accelerators, but many applications of laser-accelerated ion beams will not only require a low cost, compact system but also require operation at high repetition rates (>10 Hz). This paper focus the effort to characterize and optimize proton acceleration processes using 3 TW/55 fs, table-top Ti:Sapphire (Ti:Sa) laser capable to operate at 10 Hz, with this intention the maximum proton energy obtained, in a single shot, was evaluated by irradiating a variety of flat targets, from thin film to sub-micrometric film membranes designed for our purposes in a high density target array. The presented work is a previous stage and this study has the intention to be the prelude of the technological challenge, both in laser technology as well target design capable of operating at high repetition rates.
关键词： Ti:Sapphire laser,proton acceleration,thin-foil targets,high repetition rates
更新于2025-09-09 09:28:46
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Scalable heliostat calibration system (SHORT) - Calibrate a whole heliostat field in a single night
摘要： Efficient operation of a solar plant requires precise control of the solar field, in order to achieve the desired flux on the receiver. In order to do so, accurate knowledge about the relation between heliostat axis encoder values and the actual orientation of the reflective surface is essential. Such information is gained from heliostat calibration, making it an essential part of plant operation. Being able to perform such a calibration frequently allows maintaining high efficiency of the solar field, by compensating for drift or other deviations which can occur over time.Such a solution is imperative for using small sized heliostats, where the solar field potentially containstens or even hundreds of thousands of them.Even for whatever heliostat such a calibration allowsa more precise control on their aiming point leading to a better plant performance. The presented solution addresses this withan automatic procedure, which is able to calibrate a full solar field during one night by using cameras and artificial targets within the solar field. The method has been successfully tested at the Plataforma Solar de Almeria (PSA), showing that a beam accuracy of about 0.6 mrad can be achieved.
关键词： heliostat calibration,artificial targets,solar field,kinematic model,camera
更新于2025-09-04 15:30:14