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An Automated Setup for Measuring the Light-Scattering Characteristics of Samples with Rough Surfaces at Laser Wavelengths in the Range of 0.35–1.1 μm
摘要： The description and the operating algorithm of an automated scanning device, which is constructed according to the scheme of a two-coordinate goniophotometer and is intended for measuring the bidirectional reflection function (BDRF) of samples with different degrees of surface roughness at laser wavelengths of 0.53, 0.63, and 1.06 μm, are described. The relative measurement error of the BDRF is 6–9%. Special software and the design features allow one to vary the time and scanning step of the device, while the presence of two measurement channels makes it possible to use radiation sources with a nonstabilized output power. The device has the ability to displace the operating spectral range to the region of the middle and far IR range.
关键词： rough surfaces,BDRF,automated setup,bidirectional reflection function,laser wavelengths,light-scattering characteristics
更新于2025-09-12 10:27:22
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A capacitor based fast I-V characteristics tester for photovoltaic arrays
摘要： In order to efficiently evaluate the operating status of photovoltaic (PV) arrays, a design of fast current-voltage (I-V) characteristic tester is proposed in this paper. The tester uses the dynamic capacitor charging method to quickly sweep I-V characteristic curves. Then, a new artificial bee colony and Nelder-Mead simplex (ABC-NMS) hybrid algorithm is used to extract parameters of the single diode model of PV arrays. The experimental results show that the tester can quickly measure high-quality I-V curves of PV array and achieve accurate model parameters extraction. In addition, the root mean square error (RMSE) of curve fitting can be used to effectively indicate the partial shading condition.
关键词： I-V characteristics testing,ABC-NMS algorithm,dynamic capacitor charging,PV arrays,parameter extraction,partial shading
更新于2025-09-12 10:27:22
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Study on the matching of thermal load characteristics and photovoltaic power control in typical buildings
摘要： For the Local Heat Island Effect in the building, the connection between the spatial and temporal distribution of passenger flow and heat load characteristics of the building was analyzed, and then the required cooling load at any time in each area was solved by using the functional relationship. Furthermore, the matching strategy of cooling load and photovoltaic power in the building was proposed and verified by simulation example. Due to the above method, the distribution of cooling load in space and time was rationally controlled and photovoltaic accommodation was effectively improved. At last, the problem of the contradiction between energy supply and demand of the typical building was resolved so building-integrated photovoltaic was implemented.
关键词： refrigeration load,photovoltaic accommodation,thermal load characteristics,building-integrated photovoltaic
更新于2025-09-12 10:27:22
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Effect of plasmonic lens distribution on flight characteristics in rotational near-field photolithography
摘要： Rotational near-?eld photolithography exposes photoresists by exciting surface plasmon polaritons to realize nanopatterns with ultrahigh-resolution beyond the di?raction limit. This feature enables broad application prospects in the micro-nanomanufacturing ?eld. The lithography ?ight head, carrying a plasmonic lens (PL), with an approximately 10 nm spacer from the substrate, is the core of the system for e?ective etching. This paper investigates the ?ight state of a PL-loaded lithography head on the air ?lm, based on computational ?uid dynamics analysis. We found that the in?uence of the PL on the ?ight height produces an edge e?ect. This means that a PL fabricated on the edge region can signi?cantly a?ect the ?ight height of the head. By processing the PL at a distance of 10 μm from the edge of the slider tail block, a steady 37 nm linewidth depth pattern was ?nally realized, using a rotational near-?eld photolithography system.
关键词： edge effect,rotational near-field photolithography,flight characteristics,plasmonic lens,computational fluid dynamics
更新于2025-09-12 10:27:22
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Quality assessment of laser speckle patterns for digital image correlation by a Multi-Factor Fusion Index
摘要： Digital image correlation based on laser speckle has its unique advantages in ultra-high temperature deformation measurement. The traditional quality assessment criteria of arti?cial speckle which consider only the contrast of the speckle pattern or the morphology of the speckle particles are not suitable for laser speckle. Here, a new index, called Multi-Factor Fusion Index (MFFI), which takes the inhomogeneity of gray distribution, the mean square deviation of gray and the standard deviation of speckle particles size into consideration, is proposed to evaluate the quality of laser speckle patterns. Multi-Factor Fusion Index was compared with three commonly used criteria, the mean intensity gradient, the mean intensity of the second derivative, and the pattern quality metric combining the sum of square of subset intensity gradients (SSSIG) and the secondary auto-correlation peak height. The results showed that the proposed index had better capability of assessing the quality of laser speckle patterns. And the in?uence by external factors such as apertures, laser powers and temperatures and material factors such as roughness and light re?ectance were analyzed by MFFI. Experiments on arti?cial speckle showed that MFFI was also suitable for arti?cial speckle patterns in most cases.
关键词： Quality assessment criteria,Laser speckle characteristics,Multi-Factor Fusion Index (MFFI),Digital image correlation (DIC)
更新于2025-09-12 10:27:22
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Study of correlation between edge roughness and gas flow characteristics in laser beam fusion cutting
摘要： Fiber laser fusion cutting trials on AISI 304 stainless steel sheets of 10 mm thickness were performed with the aim to gain further insights into the striation formation process on cut edges. The study is based on a factorial Design-of-Experiment (DoE) approach with consideration of laser power, focal plane position, gas pressure, nozzle stand-off and nozzle diameter as control factors. Analyzed responses include the achievable cutting speed, the cut kerf geometry and the cut edge roughness. In addition, numerical simulations of the cutting gas flow were carried out for adapted kerf geometries and gas parameters. The evaluation of these results reveals strong correlations between experimental roughness values and the numerically computed rear-directed shear stress component within the transition zone between cutting front and cut edge surface. This finding supports the hypothesis that the particular characteristics of the boundary layer zone of the cutting gas flow affects the structure and roughness of cut edges.
关键词： Laser beam fusion cutting,edge roughness,modelling and simulation,gas flow characteristics,design-of-experiments
更新于2025-09-12 10:27:22
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Data acquisition system: On the solar photovoltaic module and weather parameters monitoring
摘要： This paper deals with a study on the data acquisition system (DAS) used for monitoring the solar photovoltaic cell/module/array parameters as well as the weather parameters. The need for facilitating DAS for photovoltaic applications is clearly evaluated based on the few practical studies taken from the literature. A system setup combining the instruments and measurement equipment required as per the objective of the study (required for selected parameters as in the user defined objective) is proposed for PV applications as well as for weather monitoring. Various parameters and their implications on the system output is clearly stated. A case study describing the Algerian PV + Weather monitoring station is discussed by highlighting the system design and its functionality in monitoring parameters.Possible research option with the monitored data from the photovoltaics and weather parameters is also listed. The paper is concluded focusing on the need and benefits of DAS and monitoring facilities for PV applications.
关键词： solar energy,PV monitoring.,PV cell/module/array characteristics,Photovoltaics,weather data
更新于2025-09-12 10:27:22
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Spatial Characteristics of Thomson Scattering Spectra in Laser and Magnetic Fields
摘要： Spatial characteristics of Thomson scattering spectra are studied for an electron moving in the circularly polarized laser field in the presence of a strong uniform magnetic field. The results show that the angular distributions of the spectra with respect to the azimuthal and polar angles exhibit different symmetries, respectively, which depend on the fields and electron parameters sensitively and significantly. Moreover, for relatively large parameters such as high laser intensity, high magnetic resonance parameter as well as large initial momentum of electron, the two lobes in spectra tend to the laser-propagating direction so that the radiation can be collimated in the forward direction. Furthermore, an important finding is that by choosing the appropriate fields and initial momentum of electron, the high frequency part of the Thomson scattering spectra can reach the frequency range of soft x-ray, in which a high radiation power per solid angle as ～1011 a.u. can be obtained.
关键词： Thomson scattering,magnetic field,spatial characteristics,laser field,soft x-ray
更新于2025-09-12 10:27:22
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Electronically controlled generation of laser pulse patterns in a synchronously pumped mode-locked semiconductor optical amplifier-fiber laser
摘要： A method for electronically controlled formation of user-defined laser pulse patterns in a synchronously pumped laser based on a semiconductor optical amplifier and an all-fiber resonator is proposed and investigated. It is demonstrated that synchronous pumping allows mode-locked operation with the laser radiation structured as an arbitrary pulse pattern repeatable on each cavity round trip. Direct electronic control of the structure and shape of the generated laser pulse patterns is implemented. The accuracy of the reproduction of modulation pulse patterns and waveforms delivered from a radiofrequency arbitrary waveform generator is examined. The time constraint on the pulse pattern formation in the steady-state mode-locked lasing regime is revealed, as well as the feasibility of the quasi-steady-state regime with on-the-lasing continuous modification of the pulse pattern structure.
关键词： mode locking,fibre lasers,laser radiation characteristics
更新于2025-09-12 10:27:22
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Study properties of monolayers with quantum dots of semiconductors A 2 B 6 and A 3 B 5
摘要： Experimental and theoretical study of semiconductor quantum dots on base multicomponent compounds such as A2B6 and A3B5 performed in the work. It was investigated the peculiarities of the electronic spectra of these nanoparticles by scanning tunneling microscopy. Analysis of results allowed us to estimate the position of the first three levels in the electron spectrum of studied nanosized objects. It was obtained good qualitative and quantitative agreement of experimental results with the theoretical estimate. Developed approach allows us to solve the inverse problem – to clarify the size of nanoscale objects when their chemical composition is precisely known.
关键词： electron energy,monolayer,current-voltage characteristics,quantum dot
更新于2025-09-12 10:27:22