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- 实验方案
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A multihertz, kiloelectronvolt pulsed proton source from a laser irradiated continuous hydrogen cluster target
摘要： A high-repetition rate laser-driven proton source from a continuously operating cryogenic hydrogen cluster target is presented. We demonstrate a debris-free, Coulomb-explosion based acceleration in the 10s of kilo-electron-volt range with a stability of about 10% in a 5 Hz operation. This acceleration mechanism, delivering short pulse proton bursts, represents an ideal acceleration scheme for various applications, for example, in materials science or as an injector source in conventional accelerators. Furthermore, the proton energy can be tuned by varying the laser and/or cluster parameters. 3D numerical particle-in-cell simulations and an analytical model support the experimental results and reveal great potential for further studies, scaling up the proton energies, which can be realized with a simple modification of the target.
关键词： high-repetition rate,laser-driven proton source,Coulomb-explosion,particle-in-cell simulations,cryogenic hydrogen cluster target
更新于2025-09-11 14:15:04
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Towards a rational design of laser-coolable molecules: insights from equation-of-motion coupled-cluster calculations
摘要： Access to cold molecules is critical for quantum information science, design of new sensors, ultracold chemistry, and search of new phenomena. These applications depend on the ability to laser-cool molecules. Rigorous theory and qualitative models can play a central role in narrowing down the vast pool of potential candidates amenable to laser cooling. We report a systematic study of structural and optical properties of alkaline earth metal derivatives in the context of their applicability in laser cooling using equation-of-motion coupled-cluster methods. To rationalize and generalize the results from high-level electronic structure calculations, we develop an effective Hamiltonian model. The model explains the observed trends and suggests new principles for the design of laser-coolable molecules.
关键词： laser cooling,alkaline earth metal derivatives,effective Hamiltonian model,quantum information science,equation-of-motion coupled-cluster methods,ultracold chemistry
更新于2025-09-11 14:15:04
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Transforming a residential building cluster into electricity prosumers in Sweden: Optimal design of a coupled PV-heat pump-thermal storage-electric vehicle system
摘要： Smart grid is triggering the transformation of traditional electricity consumers into electricity prosumers. This paper reports a case study of transforming an existing residential cluster in Sweden into electricity prosumers. The main energy concepts include (1) click-and-go photovoltaics (PV) panels for building integration, (2) centralized exhaust air heat pump, (3) thermal energy storage for storing excess PV electricity by using heat pump, and (4) PV electricity sharing within the building cluster for thermal/electrical demand (including electric vehicles load) on a direct-current micro grid. For the coupled PV-heat pump-thermal storage-electric vehicle system, a fitness function based on genetic algorithm is established to optimize the capacity and positions of PV modules at cluster level, with the purpose of maximizing the self-consumed electricity under a non-negative net present value during the economic lifetime. Different techno-economic key performance indicators, including the optimal PV capacity, self-sufficiency, self-consumption and levelized cost of electricity, are analysed under impacts of thermal storage integration, electric vehicle penetration and electricity sharing possibility. Results indicate that the coupled system can effectively improve the district-level PV electricity self-consumption rate to about 77% in the baseline case. The research results reveal how electric vehicle penetrations, thermal storage, and energy sharing affect PV system sizing/positions and the performance indicators, and thus help promote the PV deployment. This study also demonstrates the feasibility for transferring the existing Swedish building clusters into smart electricity prosumers with higher self-consumption and energy efficiency and more intelligence, which benefits achieving the ‘32% share of renewable energy source’ target in EU by 2030.
关键词： Thermal storage,Heat pump,Prosumer,Building cluster,PV optimization,Electrical vehicle
更新于2025-09-11 14:15:04
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[IEEE 2018 7th International Conference on Agro-geoinformatics (Agro-geoinformatics) - Hangzhou (2018.8.6-2018.8.9)] 2018 7th International Conference on Agro-geoinformatics (Agro-geoinformatics) - Polsar Image Crop Classification Based on Deep Residual Learning Network
摘要： PolSAR image classification is one of the most basic applications of polarimetric synthetic aperture radar (PolSAR) data, which is of great significance to the research and subsequent application of PolSAR data. Traditional PolSAR image classification methods, mainly based on a single type of target decomposition method, the dimension of feature used in the process of PolSAR image classification process is relatively less and cannot make full use of the abundant feature of the PolSAR image, which is the one of the most essential characteristics of PolSAR data. With the development of deep learning, an amount of excellent deep learning models is proposed, such as deep brief net, AlexNet, deep residual network (ResNet) and so on. The classification method based on deep learning is proved to be better than traditional methods in the classification of optical and SAR images. This paper mainly analyzes the application of ResNet model in PolSAR image classification, the effectiveness of the method was proved by comparing the classical PolSAR image classification method. Firstly, some target decomposition methods were selected to calculate the multi-dimensional feature image. Secondly, the sample points of different land cover types were manually selected, and the multi-dimensional features were extracted to form the experimental data samples. Then, the PolSAR classification model based on ResNet was constructed, and the model parameters were adjusted dynamically according to the experimental sample data. Finally, the trained model was applied to the classification of experimental data, and the accuracy of the model was assessed by calculating the Kappa index of the classification result. In this paper, a quantitative index is proposed to calculate the ability of each feature to distinguish different land cover types, and the weak distinguishing feature was deleted to reduce the influence of classification independent features on the model and to improved classification accuracy. As for the speckle noise, the PolSAR image was preprocessed by simple linear iterative clustering the experimental image was divided into a determined number of superpixel blocks, and the PolSAR image classification based on super-pixel blocks. Experimental results show that the PolSAR image classification method based on ResNet is conducive the comprehensive utilization of multi- dimensional features of PolSAR image, the classification accuracy of PolSAR image is better than that of the classic classification method. The optimization of feature sets is beneficial to reduce model training time and improve the classification accuracy of PolSAR image as well. The superpixel segmentation is beneficial to reduce speckle noise and further improves the accuracy of classification.
关键词： Simple linear iterative cluster,PolSAR image,Crop classification,Deep residual network,Feature optimization
更新于2025-09-11 14:15:04
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Precise sputtering of silicon dioxide by argon cluster ion beams
摘要： In this work, the sputtering yields of SiO2 by the argon cluster ion beam with incident angles 0° and 45° have been studied experimentally. The kinetic energy of the primary cluster ions was in the range of E = 5–23.5?keV, and the mean cluster size was Nmean = 100–1000 atom/cluster. It is found that, when the energy per cluster atom quantity E/N is comparable to the binding energy of the solid (of the order of several eV), the yields of atoms sputtered per primary atom Y/N, at the incident angle 45°, is 4 times greater than at normal incidence. Conversely, when energy E/N is significantly above the binding energy of the solid (~ 100?eV), the sputtering yields for the incident angles 0° and 45° have the same values.
关键词： kinetic energy,incident angles,argon cluster ion beam,sputtering yields,cluster size,silicon dioxide
更新于2025-09-10 09:29:36
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Formation energies of CdSe wurtzoid and diamondoid clusters formed from Cd and Se atomic clusters
摘要： Cadmium Selenide thermodynamic formation energies at the molecular and nanoscale range are investigated using density functional theory. The investigation is performed using wurtzoid and diamondoid clusters that represent the wurtzite and zincblende structures at the molecular and nanoscale size range for a cluster number of atoms n ≤ 26. Cd and Se atomic clusters are optimized and used to provide component atomic cluster energies. Although both Cd and Se clusters at the nanoscale have di?erent phases than bulk, the results show that Gibbs free energy, enthalpy, and entropy of formation of CdSe are close to their experimental bulk energies of formation within errors of experimental measurements. CdSe wurtzoids generally have higher absolute (more negative) Gibbs free energy of formation than CdSe diamondoids indicating more stable wurtzoid molecules which is also the case at bulk. The absolute Gibbs free energy of wurtzoids is also higher than experimental value (more negative) because of surface e?ects at the nanoscale. Enthalpy of formation indicates an exothermic reaction of Cd and Se clusters as is the case at bulk. The entropy of formation of all clusters is size-sensitive and converges towards bulk experimental measurements. Both wurtzoids and diamondoids members contain Cd13Se13 cluster which is the most investigated magic CdSe cluster.
关键词： Density functional theory,CdSe,Cluster
更新于2025-09-10 09:29:36
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Construction of Crystalline One-Dimensional Infinite Argentophilic Silver Alkynyl Assemblies and Their Luminescence Properties
摘要： Four crystalline one-dimensional (1-D) silver alkynyl assemblies, namely, [Ag11(tBuC≡C)7(CH3COO)4]n (1), [Ag21(tBuC≡C)11(PhCOO)10]n (2), [Ag16(m-F-PhC≡C)12(CF3COO)4(CH3CN)4]n (3) and [Cl@Ag14(PhC≡C)10(CF3SO3)3]n (4), have been obtained by reacting polymeric [AgC≡CR]n with silver salts under mild solvothermal conditions. Compound 1 and 3 are coordination polymer of irregular silver alkynyl clusters. Compound 2 consists of well-defined parallel Ag3 triangles columns. Compound 4 is chains of chloride templated cage-like silver clusters. Compound 2 - 4 show temperature-sensitive luminescent behaviors. Amongst, compound 2 and 3 display dual-emissive characteristic at low temperature. By correlating the structures and properties of four silver compounds, we found that the non-emissive behavior of compound 1 could be tentatively assigned to the absence of any aryl groups on the ligands.
关键词： silver cluster,luminescence,1-D chain,argentophilic interactions
更新于2025-09-10 09:29:36
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Heliostat field cleaning scheduling for Solar Power Tower plants: A heuristic approach
摘要： Soiling of heliostat surfaces due to local climate has a direct impact on their optical efficiency and therefore a direct impact on the productivity of the Solar Power Tower plant. Cleaning techniques applied are dependent on plant construction and current schedules are normally developed considering heliostat layout patterns, providing sub-optimal results. In this paper, a method to optimise cleaning schedules is developed, with the objective of maximising energy generated by the plant. First, an algorithm finds a cleaning schedule by solving an integer program, which is then used as a starting solution in an exchange heuristic. Since the optimisation problems are of large size, a p-median type heuristic is performed to reduce the problem dimensionality by clustering heliostats into groups to be cleaned in the same period.
关键词： Solar energy,Routing problems,Cluster analysis,Scheduling
更新于2025-09-10 09:29:36
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Hydrogen gas sensing properties of WO3 sputter-deposited thin films enhanced by on-top deposited?CuO nanoclusters
摘要： Magnetron-based gas aggregation cluster source (GAS) was used to prepare high-purity CuO (cupric oxide) nanoclusters on top of sputter-deposited thin film of tungsten trioxide (WO3). The material was assembled as a conductometric hydrogen gas sensor and its response was tested and evaluated. It is demonstrated that addition of CuO clusters noticeably enhances the sensitivity of the pure WO3 thin film. With an increasing amount of CuO clusters the sensitivity of CuO/WO3 system rises further. When CuO clusters form a sufficiently thick and compact layer, the resistance response is reversed. Based on the sensorial behavior, conventional and near-ambient pressure X-Ray photoemission spectroscopies, and resistivity measurements, we propose that the sensing mechanism is based on the formation of nano-sized p-n junctions in between p-type CuO and n-type WO3. The advantages of the GAS technique for preparing sensorial and/or catalytically active materials are emphasized.
关键词： Hydrogen gas sensor,Gas aggregation cluster source,Magnetron sputtering,Tungsten oxide,Nanocomposites,Cupric oxide
更新于2025-09-10 09:29:36
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Interfacial uploading of luminescent hexamolybdenum cluster units onto amino-decorated silica nanoparticles as new design of nanomaterial for cellular imaging and photodynamic therapy
摘要： The present work introduces a facile synthetic route to embed phosphorescent K2[{Mo6I8}I6] and (nBu4N)2[{Mo6I8}(CH3COO)6] clusters (C) onto silica-water interface of amino-decorated silica nanoparticles (SNs, 60±6 nm). The assembled C-SNs gain in the luminescence intensity, which remains stable within three months after their assembly. High uptake capacity of the clusters (8700 of K2[{Mo6I8}I6] and 6500 of (nBu4N)2[{Mo6I8}(CH3COO)6] per the each nanoparticle) derives from ionic self-assembly and coordination bonds between the cluster complexes and ionic (amino- and siloxy-) groups at the silica surface. The coordination via amino- or siloxy-groups restricts aquation and hydrolysis of the embedded clusters, in comparison with the parent K2[{Mo6I8}I6] and (nBu4N)2[{Mo6I8}(CH3COO)6. High potential of the assembled nanoparticles in the ROS generation was revealed by EPR measurements facilitated by spin trapping. The high positive charge and convenient colloid stability of the assembled C-SNs hybrids are the prerequisite for their efficient cellular uptake, which is exemplified in the work by MCF-7 cell line. The measured dark and photoinduced cytotoxicity of the C-SNs hybrids reveals significant photodynamic therapy effect on the MCF-7 cancer cell line versus the normal cells. This effect is entirely due to the embedded clusters and is dependent on the chemical composition of the cluster.
关键词： hexamolybdenum cluster,adsorption,silica nanoparticles,cell internalization,photodynamic therapy,luminescence
更新于2025-09-10 09:29:36