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oe1(光电查) - 科学论文

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出版时间
  • 2019
研究主题
  • photovoltaic power generation system
  • sensitivity analysis
  • Monte Carlo
  • fuzzy layering evaluation method
应用领域
  • Electrical Engineering and Automation
机构单位
  • Xi’an Jiaotong University
798 条数据
?? 中文（中国） ▾

  • A branch and price algorithm for EOS constellation imaging and downloading integrated scheduling problem

    摘要： Earth observation satellite (EOS) constellation imaging and downloading integrated scheduling (EOSCIDIS) is a challenging optimization problem with several engineering applications. Given a large number of imaging requests and a constellation consisting of a group of EOSs, a workable schedule must be developed for each EOS to allow for imaging and downloading in the most efficient manner given a certain scheduling horizon. No studies have proposed exact algorithms for the EOSCIDIS problem, although it has considerable potential for applications. In this paper, we developed a branch and price (B&P) algorithm for the EOSCIDIS problem. First, we decomposed the problem by extracting the sub-structure of the problem, and the decomposition resulted in a master problem and multiple pricing problems. Solving the linear relaxed master problem with column generation (CG) method provides a very tight upper bounds for the primal problem. We then embedded the CG process into a branch and bound (B&B) framework to find optimal integer solutions. In order to accelerate the convergence of the algorithm, we developed a heuristic utilizing the generated columns to construct feasible integer solutions to prune B&P tree branches earlier. We tested the B&P algorithm on highly-simulated instances that are constructed according to the Chinese Gaofen-1 satellite and 3 types of random instances which correspond to short, medium and long term scheduling respectively. Both results show that our method could find high-quality solutions with optimality gap less than 10% for most instances using reasonable computational costs.

    关键词： Branch and price,Primal dual column generation,Integrated scheduling,EOS constellation

    更新于2025-09-04 15:30:14

  • Ba10Zn7M6Q26: Two New Mid-infrared Nonlinear Optical Crystals with T2 Supertetrahedron 3D Framework

    摘要： Two new mid-infrared (MIR) nonlinear optical (NLO) chalcogenide crystals, Ba10Zn7In6S26, 1 and Ba10Zn7Ga6Se26, 2 are discovered by traditional solid state reactions. 1 and 2 are isostructural and they represent a novel three-dimensional (3D) framework made by apexe-sharing T2 supertetrahedron 2D layers that are stacked alternately by another kind of T2 supertetrahedra though sharing apexes along the c direction, with T1 tetrahedra inserting in the tunnels and Ba2+ cations locating both in the voids and tunnels. Among them, 1 shows attractive MIR NLO properties of a wide band gap of 3.0 eV, a strong second harmonic generation (SHG) signal about 4.1 times that of the commercial AgGaS2 at particle sizes of 30–46 μm under a 2.05 μm laser radiation, and a high LDT of 37.2 times that of benchmark AgGaS2 at particle sizes of 150–210 μm under a 1.064 μm laser radiation. This distinguishes 1 as a new promising MIR NLO material. In addition, the density functional theory (DFT) analyses suggest that the SHG response of 1 comes mainly from the electronic transitions from S 3p to Ba 5d, Zn 4s, Zn 3d, In 5s, In 5p states.

    关键词： chalcogenide,mid-infrared,second harmonic generation,laser damage threshold,nonlinear optical,supertetrahedron

    更新于2025-09-04 15:30:14

  • Clusters partition and zonal voltage regulation for distribution networks with high penetration of PVs

    摘要： Integration of distributed generation (DG) at large scale with high penetration challenges the radial structure of the traditional distribution networks and the effectiveness of the conventional voltage regulation methods. In this study, the clusters partitioning and voltage regulation are researched. The modified electrical distance is introduced. An effective method, based on spectral clustering algorithm, is proposed for the partitioning of the DG network via the judgement of critical load buses. Two-stage voltage regulation optimisation is realised in each sub-community. The optimal objects are the minimal voltage fluctuation and the network loss of the distributed network. The independent variables are reactive-power absorption and active-power curtailment for each controllable photovoltaic node. An advanced particle swarm optimisation algorithm is applied to the voltage regulation for the sub-communities. After a case study of the IEEE 33-bus system, a regional distribution network in Anhui province of China is analysed. Simulation results indicate that the node voltages are stabilised with the improvement of power quality employing the proposed clusters partitioning method and zonal power control scheme.

    关键词： spectral clustering,particle swarm optimisation,voltage regulation,distributed generation,photovoltaic

    更新于2025-09-04 15:30:14

  • Optimum chirp for efficient terahertz generation from two-color femtosecond pulses in air

    摘要： We compare detailed spatio-temporal propagation simulations with experiments on generation of terahertz (THz) pulses in single ?laments with two-color optical excitation, which elucidates the mechanism whereby positively chirped optical pulses lead to the maximum THz yield. The long-wavelength components in the leading edge of the positively chirped 2x-pulse preserve the overlap with the x-pulse. The THz yield is extremely sensitive to the temporal overlap: for a 35-fs x-pulse, the yield decreases by an order of magnitude upon a x–2x pulse shift of only 5 fs.

    关键词： terahertz,chirp,two-color excitation,femtosecond pulses,THz generation

    更新于2025-09-04 15:30:14

  • Subcycle interference in high-order harmonic generation from solids

    摘要： Different from the high-order harmonic generation (HHG) from gases, we ?nd that the yield of HHG from solids exhibits unexpected modulations as a function of the driving laser intensity and wavelength. Its mechanism can be unraveled by the interference between currents inside the solids induced by two adjacent Zener tunneling events. Our simulations agree well with the experimental measurements of HHG from ZnSe and solid Ar. We also ?nd that the dephasing time plays a key role in this subcycle interference and can turn it on or off by controlling the overlap between the channels. It provides an avenue to optimize the ultrafast electron dynamics and HHG emission processes in solids, which will be useful for the compact ultrafast EUV light sources. We also propose an experimental scheme by using ultrashort lasers to explore this interference in other solid materials.

    关键词： high-order harmonic generation,solids,ultrafast electron dynamics,Zener tunneling,dephasing time

    更新于2025-09-04 15:30:14

  • Effective quenching and excited-state relaxation of a Cu(I) photosensitizer addressed by time-resolved spectroscopy and TDDFT calculations

    摘要： Homogenous photocatalytic systems based on copper photosensitizers are promising candidates for noble metal free approaches in solar hydrogen generation. To improve their performance, a detailed understanding of the individual steps is needed. Here, we study the interaction of a heteroleptic copper (I) photosensitizer with an iron catalyst by time-resolved spectroscopy and ab initio calculations. The catalyst leads to rather efficient quenching of the 3MLCT state of the copper complex, with a bimolecular rate being about three times smaller than the collision rate. Using control experiments with methyl viologen, an appearing absorption band is assigned to the oxidized copper complex demonstrating that an electron transfer from the sensitizer to the iron catalyst occurs and the system reacts along an oxidative pathway. However, only about 30% of the quenching events result in an electron transfer while the other 70% experience deactivation indicating that the photocatalytic performance might suffer from geminate recombination.

    关键词： Solar hydrogen generation,Time-resolved spectroscopy,Ab initio calculations,Copper photosensitizers,Electron transfer

    更新于2025-09-04 15:30:14

  • Three Cadmium Tartratoborates with Good Second Harmonic Generation (SHG) or Luminescence Performances

    摘要： Three new cadmium(II) tartratoborates, namely, Cd5[(C4H2O6)2B]2(H2O)8·3H2O (1), K2Cd4[(C4H2O6)2B]2(H2O)2 (2), and Li0.92K1.08Cd1.5[(C4H2O6)2B](H2O)2 (3), have been successfully synthesized by the hydrothermal method. Compounds 1?3 belong to centric C2/c, acentric Pc, and the polar C2, respectively. Through based on the same hybrid borate?tartrate [(C4H2O6)2B]5? anions, they exhibit different structures. The [(C4H2O6)2B]5? anion is composed of two tartrate anions and a B(OH)4? unit. Compound 1 features a novel 2D {Cd3[(C4H2O6)2B]2(H2O)2}4? anionic layers and [Cd2O10] dimers, forming tunnels of large 14-MRs which are filled by the non-coordination water molecules. Compound 2 has a characteristic 3D network based on {Cd2[(C4H2O6)2B]}? units interlinked via carboxylate groups, forming tunnels of 11-MRs, half of which stuffed with the K+ ions. Compound 3 features 2D {Cd4[(C4H2O6)4B]}3+ layers which are separated by K/Li ions. Luminescent studies suggest that they emit blue light. Compounds 2 and 3 display phase-matchable second harmonic generation signs of about 3.2× and 1.5× KH2PO4, respectively.

    关键词： luminescence,hydrothermal method,cadmium tartratoborates,second harmonic generation

    更新于2025-09-04 15:30:14

  • [IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - A New Neural Approach of Supervised Change Detection in SAR Images Using Training Data Generation with Concurrent Self-Organizing Maps

    摘要： This paper proposes a new neural approach for supervised change detection in Synthetic Aperture Radar (SAR) images using Training Data Generation based on Concurrent Self-Organizing Maps (TDG-CSOM). The proposed model is based on the idea to substitute the authentically labeled sample set with the virtual training data generated by the CSOM system. The proposed change detection algorithm has the following processing stages: (a) TDG-CSOM; (b) Multi-Layer Perceptron (MLP) classifier training using the virtual dataset obtained by TDG-CSOM; (c) concatenation of the corresponding pixels belonging to the SAR bi-temporal image; (d) MLP classification to obtain the change map. The proposed method is implemented and evaluated using a TerraSAR-X image acquired in the Fukushima region, Japan, before and after tsunami. The experimental results confirm the effectiveness of the proposed approach.

    关键词： training data generation,SAR images,Supervised change detection,concurrent self-organizing maps

    更新于2025-09-04 15:30:14

  • [IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Can We Generate Good Samples for Hyperspectral Classification? — A Generative Adversarial Network Based Method

    摘要： The insufficiency of training samples is really a great challenge for hyperspectral image (HSI) classification. Samples generation is a commonly used technique in deep learning based remote sensing field which can extend the training set. However, previous methods ignore the real distribution of the training samples in the feature space and thus can hardly ensure that the generated samples possess the same patterns with the real ones. In this paper, we propose a generative adversarial network based method (SpecGAN) to handle this problem. Different from traditional GAN framework where the generated samples have no categories, for the first time we take the label information into consideration for hyperspectral images. Feeding a random noise z and a class label vector y into the generator, we can get a spectral sample of the corresponding category. The experiments on the Pavia University data set demonstrate the potential of the proposed SpecGAN in spectral samples generation.

    关键词： hyperspectral image classification,generative adversarial network,Sample generation,deep learning

    更新于2025-09-04 15:30:14

  • [IEEE 2018 11th International Symposium on Communication Systems, Networks and Digital Signal Processing (CSNDSP) - Budapest (2018.7.18-2018.7.20)] 2018 11th International Symposium on Communication Systems, Networks & Digital Signal Processing (CSNDSP) - Multi-core Fiber Based Mm-wave Generation, Radio-over-Fiber, and Power-over-Fiber

    摘要： We propose a multi-core fiber (MCFs) based concept which simultaneously use to generate millimeter wave (mm-wave) signal; a radio over fiber link; and a power over fiber link. In the proposed system, some cores of MCFs are used to generate mm-wave signal using an optoelectronic oscillator (OEO) topology, few of the cores are used to transport data modulated mm-wave signal through radio-over-fiber (RoF) technology while others are used to transmit optical power for biasing the amplifier in the remote antenna unit with help of power over fiber (PoF) technology and photonic power converter in a small cell architecture of the future 5G technology.

    关键词： Multi-core fiber,mm-wave generation,power-over-fiber,radio-over-fiber

    更新于2025-09-04 15:30:14