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Enhance the solar cell efficiency by reduction of reflection losses
摘要： The enhancement of the solar cell efficiency field has been achieved in many methods due to the different factors and conditions that led to loss the solar energy .This work deals with the increasing of the efficiency of solar cell that made of single crystalline silicon .This increment achieved by the reduction of biggest type of losses of the conversion efficiency named reflection . by using two methods first ; forming grooves on the surface using pulse Nd:YAG laser with max energy 1J and pulse width 10ns, using the fast and accurate movement of the 3D optical galvo mirror scanning system to form the grooves , the second method was by deposition nanomaterials as Silver (Ag) and Cadmium telluride (CdTe) to constitute an antireflection layer for the incident solar spectrum . The effect of antireflection layer material type and the effect of incident light angle on the reflection had been studied in this work .The reflectance had been measured by a system designed and built to give the reflection for angles ranged 0 – 180 degree controlled by Microcontroller. The result inducate that increase in conversion efficiency was 28.3% for Ag/Si , and 32.9% for CdTe/Si than the original efficiency of Si solar cell.
关键词： silicon solar cell,reflectance,laser texture,nanoparticles,antireflection surfaces
更新于2025-09-11 14:15:04
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Biocompatibility of micro/nanostructures nitinol surface via nanosecond laser circularly scanning
摘要： We present three novel scanning patterns on nitinol by nanosecond laser for controllable fabricating biocompatible micro/nanostructures. The surface morphology and formation mechanism of micro/nanostructures were respectively observed and analyzed. The production of surface oxide film provides a biocompatible cell living environment. Also, micro/nanostructures greatly promote cell adherence and growth. It is worth noting that ns laser circularly scanning can effortlessly produce various micro/nanostructures and endue biologically inert nitinol implants with enhanced osseointegration and bioactivity.
关键词： Microstructure,Nitinol,Laser processing,Surfaces,Biocompatibility
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP) - Bochum, Germany (2019.7.16-2019.7.18)] 2019 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP) - Experimental Investigation of Terahertz Wave Scattering by Statistically Controlled Rough Surfaces
摘要： In this work, the experimental investigation of electromagnetic wave scattering by statistically controlled rough surfaces in the lower THz band is demonstrated. Rough surfaces with height fluctuations following normal statistics are fabricated using two different 3D printing techniques. The results presented here confirm that the surface roughness has a noticeable effect on the level of the diffuse scattering energy. In the future, the applied method can be used to validate analytical models as well as to gain scattering patterns from more complicated rough surface structures which fall outside the limits of most analytical approximations.
关键词： scattering measurements,statistically controlled rough surfaces,THz communication
更新于2025-09-11 14:15:04
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[IEEE 2017 IEEE 44th Photovoltaic Specialists Conference (PVSC) - Washington, DC (2017.6.25-2017.6.30)] 2017 IEEE 44th Photovoltaic Specialist Conference (PVSC) - High resolution THz scanning for optimization of dielectric layer opening process on doped Si surfaces
摘要： Diffused IBC solar cells based on non-fire-through (NFT) metallization can achieve higher performance with respect to FT metallization, thanks to lower contact resistance. Less resistive contacts allows for lower metal fraction and thus lower contact recombination. For the application of NFT contacts, the rear side dielectric passivation layer needs to be locally opened. Standard processes for dielectric opening include laser ablation, use of etching pastes or masking and etching. In all this cases it is important that the opening process does not cause any damage to the diffusion below the contacts. We present a fast inspection method based on THz near-field scanning that allows investigating the diffusion layers after dielectric opening with spatial resolution suited for the small feature size of standard IBC solar cells. This method can be used to optimize crucial parameters of the dielectric opening without processing full cells. In this paper, we use THz scanning to optimize the curing temperature of the etch paste used to open the dielectric passivation layers on solar cells half-fabricates. After optimization, full cells are processed with top efficiency of 20.8%.
关键词： THz scanning,NFT metallization,dielectric layer opening,solar cells,doped Si surfaces
更新于2025-09-11 14:15:04
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Biocompatibility Investigation of Hybrid Organometallic Polymers for Sub-Micron 3D Printing via Laser Two-Photon Polymerisation
摘要： Hybrid organometallic polymers are a class of functional materials which can be used to produce structures with sub-micron features via laser two-photon polymerisation. Previous studies demonstrated the relative biocompatibility of Al and Zr containing hybrid organometallic polymers in vitro. However, a deeper understanding of their effects on intracellular processes is needed if a tissue engineering strategy based on these materials is to be envisioned. Herein, primary rat myogenic cells were cultured on spin-coated Al and Zr containing polymer surfaces to investigate how each material affects the viability, adhesion strength, adhesion-associated protein expression, rate of cellular metabolism and collagen secretion. We found that the investigated surfaces supported cellular growth to full confluency. A subsequent MTT assay showed that glass and Zr surfaces led to higher rates of metabolism than did the Al surfaces. A viability assay revealed that all surfaces supported comparable levels of cell viability. Cellular adhesion strength assessment showed an insignificantly stronger relative adhesion after 4 h of culture than after 24 h. The largest amount of collagen was secreted by cells grown on the Al-containing surface. In conclusion, the materials were found to be biocompatible in vitro and have potential for bioengineering applications.
关键词： biomaterials,bioactive surfaces,laser two-photon polymerisation,tissue engineering,hybrid organometallic polymers
更新于2025-09-11 14:15:04
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[IEEE 2018 IEEE 5G World Forum (5GWF) - Silicon Valley, CA, USA (2018.7.9-2018.7.11)] 2018 IEEE 5G World Forum (5GWF) - Engineering the 5G Environment
摘要： This summary paper examines how engineered electromagnetic surfaces can be applied to alter the way radio signals propagate in dense urban environments in order to enhance coverage or improve densification, thereby enabling the engineering of the environment in a way that enhances radio spectrum use in smart cities. Examples of designs and deployments in the Wi-Fi and millimeter-wave bands are presented for both indoor and outdoor applications.
关键词： Electromagnetic engineered surfaces,smart cities,5G communications,millimeter-waves
更新于2025-09-11 14:15:04
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Can Color and Motion Information Be Used to Disentangle the Influence of Multiple Light Sources on Gloss Perception?
摘要： Previous results suggest that the glossiness of a surface is systematically underestimated when adjacent highlights from different light sources overlap to such an extent that they appear as a single, expanded highlight. Here we investigated how the availability of color- and motion-induced information, which may help to unravel such merged highlights, affects gloss constancy. We used images of computer-generated scenes where a complex 3D object made of glossy material was illuminated by three point light sources, which had varying distances to each other. The point lights were either all achromatic or they differed clearly in their color and the test object was either presented statically or rotating. The subjects had to adjust the smoothness of a match object illuminated by a single achromatic point light so that it appeared to have the same glossiness as the test object. The results show that color information contributes to gloss constancy in this situation: If it was available, the perceived glossiness remained almost invariant with changes in the degree of overlap between the highlights. This suggests that highlights of different color are processed separately. Motion information had no such effect but only led to a general increase in perceived glossiness.
关键词： color,gloss perception,motion,surfaces/materials,gloss constancy,light
更新于2025-09-11 14:15:04
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SCATTERING AND TRANSMISSION OF WAVES IN MULTIPLE RANDOM ROUGH SURFACES: ENERGY CONSERVATION STUDIES WITH THE SECOND ORDER SMALL PERTURBATION METHOD
摘要： Energy conservation is an important consideration in wave scattering and transmission from random rough surfaces and is particularly important in passive microwave remote sensing. In this paper, we study energy conservation in scattering from layered random rough surfaces using the second order small perturbation method (SPM2). SPM2 includes both first order incoherent scattering and a second order correction to the coherent fields. They are combined to compute the total reflected and transmitted powers, as a sum of integrations over wavenumber kx, in which each integration includes the surface power spectra of a rough interface weighted by an emission kernel function (assuming the roughness of each interface is uncorrelated). We calculate the corresponding kernel functions which are the power spectral densities for one-dimensional (1D) surfaces in 2D scattering problems and examine numerical results for the cases of 2 rough interfaces and 51 rough interfaces. Because it is known that the SPM when evaluated to second order conserves energy, and it can be applied to second order for arbitrary surface power spectra, energy conservation can be shown to be satisfied for each value of kx in the kernel functions. The numerical examples show that energy conservation is obeyed for any dielectric contrast, any layer configuration and interface, and arbitrary roughness spectra. The values of reflected or transmitted powers predicted, however, are accurate only to second order in small surface roughness.
关键词： roughness spectra,wave scattering,random rough surfaces,SPM2,transmission,passive microwave remote sensing,layered random rough surfaces,small perturbation method,power spectral densities,Energy conservation,dielectric contrast
更新于2025-09-10 09:29:36
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Quantitative evaluation of skin surface roughness using optical coherence tomography in vivo
摘要： The quantitative monitoring of skin topography is important in the field of cosmetics and dermatology. The most widespread method for determining skin roughness in vivo is to use skin microrelief, PRIMOS device, which allows a noninvasive, fast and direct measurement of the skin surface. However, it has drawbacks, such as the interference of backscattering from volumetric skin and motion artifacts. In this study, we demonstrate the potential of OCT for providing reliable and quantitative skin surface roughness. In order to evaluate the performance of OCT for skin surface analysis, different types of skin phantoms are fabricated and measured. We utilize OCT to identify the effect of cosmetics as well as human skin topology for various aging groups and different skin regions. Skin surface roughness parameters based on ISO 25178 part 2 standard definitions are then derived from home-built image processing software and compared with one acquired from PRIMOS. Our results show that skin surface geometry acquired from 3D OCT images is well quantified to complex wrinkle structure and robust to the angle of the subject. Since OCT enables to present topology and volumetric skin anatomy quantitative skin simultaneously, it would be a useful tool to deliver comprehensive and intuitive information in dynamic skin observations.
关键词： Surfaces,Tomography,Biomedical image processing
更新于2025-09-10 09:29:36
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Reference Module in Chemistry, Molecular Sciences and Chemical Engineering || Aryl–Aryl Coupling on Semiconductor Surfaces
摘要： Bottom-up strategies in nanotechnology offer unprecedented precision in fabrication of functional structures and devices. Soon after the advent of scanning probe microscopies in the 1980s, it was demonstrated that on-surface nanoobjects may be constructed at ultimate level of control—one atom at a time. Later on, it was shown that even a chemical reaction between two molecular entities is manageable in a stepwise fashion—all steps of a chemical reaction may be induced with scanning tip at will. The limits of precision have been reached. If one considers practical implementations, however, a major obstacle of tip-induced processes appears to be their tediousness. Alternative, fast, yet, precise routes to nanostructure formation are sought. In such a context non-locally induced procedures seem to be especially rewarding. There are, still, at least two expectations with regard to nonlocally induced chemical reactions. First, there is a need for a kind-of-trigger that will allow for a controlled activation of a given procedure. Second, it would be beneficial if the whole process is controllable by means of additional constraints, for example, a specific substrate may lead to a particular nanoobject morphology. An impressive example of such a strategy is aryl halide C–C coupling on surfaces allowing for construction of various 1D and 2D structures. In particular, when aryl halide C–C coupling is combined with cyclodehydrogenation reaction it facilitates synthesis of miscellaneous graphene derivatives, such as nanoribbons of different widths and diverse edge topology.
关键词： On-Surface Polymerization,Semiconductor Surfaces,Aryl–Aryl Coupling,Ge(001):H Surface,Rutile Titania
更新于2025-09-10 09:29:36