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Variation in Structural, Electrical and Optical Properties of Selenium Nanowires After Irradiation with Ni6+ Ions
摘要： The effect of Ni ion irradiation on selenium nanowires of 80 nm diameter is studied in the present work. Se nanowires were prepared by using electrodeposition technique in polycarbonate membrane. Changes in the structural, optical and electrical properties are studied using XRD, UV/Vis spectroscopy and current–voltage characteristics, of the pristine and irradiated samples. X-ray diffraction study confirms the variation in peak intensity without any shifting in peak position. Variation in texture coefficient and grain size was clearly observed which is a consequence of changing plane orientation, irradiation induced grain growth and grain fragmentation. A decrease in the optical band gap takes place due to interstitial energy band states in the vicinity of conduction and valence band. IVC also shows variation in the conductivity which is due to the generation of current carriers with the passage of energetic ions.
关键词： Ion irradiation,Optical analysis,Selenium nanowires,Impedance,Electrical properties,Structural analysis
更新于2025-09-23 15:23:52
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Recent advances of plasmonic nanoparticle-based optical analysis in homogeneous solution and at the single-nanoparticle level
摘要： Plasmonic nanoparticles with special localized surface plasmon resonance (LSPR) characters have been widely applied for optical sensing of various targets. With the combination of single nanoparticle imaging techniques, dynamic information of reactions and biological processes is obtained, facilitating the deep understanding of their principle and design of outstanding nanomaterials. In this review, we summarize the recently adopted optical analysis of diverse analytes based on plasmonic nanoparticles in both homogeneous solution and single-nanoparticle level. A brief introduction of LSPR is first discussed. Colorimetric and fluorimetric homogeneous detection examples by using different sensing mechanisms and strategies are provided. Single plasmonic nanoparticle-based analysis is concluded in two aspects: visualization of chemical reactions and understanding of biological processes. The basic sensing mechanisms and performances of these systems are introduced. Finally, this review highlights the challenges and future trend of plasmonic nanoparticle-based optical analysis system.
关键词： Plasmonic nanoparticles,Single-nanoparticle level,Fluorimetric assays,Chemical reactions,Localized surface plasmon resonance (LSPR),Optical analysis,Homogeneous solution,Colorimetric assays,Biological processes
更新于2025-09-23 15:21:01
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Development of two new semi-empirical formulas for estimation of solar absorptance in circular cavity receivers
摘要： In this paper two new semi-empirical formulas for calculating the equivalent absorptance of solar irradiation at the inner surface of cylindrical cavities is proposed. The multiple re?ections that occur at the interior of the cavity were ?rst analyzed considering a two-dimensional geometrical approach and thus the ?rst analytical relationship for the equivalent solar absorptance was revealed. In addition, a three-dimensional ray tracing analysis was conducted through Solidworks Flow Simulation. Several di?erent cavity aperture’s widths as well as solar absorptance coe?cients (α = 0.5–0.9 per 0.1) were examined in both analyses and it was found that the two dimensional analytical approach exceeds the simulation by 1.50–6.83% on average going from the highest to the lowest solar absorptance value. Finally, two new correlations were developed for correcting the analytical approach according to the 3D ray tracing with the optimum between them to provide a mean error at the equivalent solar absorptance calculation of about 0.78%, 0.55%, 0.40%, 0.21% and 0.18% for the ?ve di?erent absorptance coe?cients were examined.
关键词： Solidworks Flow Simulation,Solar absorptance,Cavity receiver,Optical analysis,New correlation
更新于2025-09-19 17:15:36
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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)] - A multiphysics approach to an automotive headlamp low beam cut-off line
摘要： In this study, cumulative effect of warpage due to injection molding process and thermal expansion of plastic parts because of heat generated by the light functions on headlamp low beam cut-off line has been inspected by virtual methods. Firstly, deformed mesh generated by mold flow analysis for light module bracket and headlamp housing have been converted to solid computer aided design (CAD) models by the help of commercially available CAD software. Thermal finite element analysis (FEA) has been performed at ambient temperature of 22°C with the light functions all on and stabilized temperature map has been exported for use as load input for structural FEA. After structural FEA, directional displacements and angular rotations of focal point of the light module have been extracted as inputs for optical analysis. Optical analysis results have been inspected to understand the effects on low beam cut-off line of the Headlamp.
关键词： automotive headlamp,low beam cut-off line,multiphysics,thermal expansion,FEA,warpage,optical analysis
更新于2025-09-09 09:28:46
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Characterization of flame front propagation during early and late combustion for methane-hydrogen fueling of an optically accessible SI engine
摘要： In recent years, hybrid and fully electric vehicles have received significant consideration since they represent an alternative sustainable transport to the conventional fossil-fuel powered vehicles. However, a worldwide implementation of this alternative propulsion can induce large and undesirable peak demands in distributed power systems. In this context, natural gas spark ignition engines are a promising form of technology to supply part of the energy demand. The main limitations related to low laminar flame propagation speed and poor lean-burn capabilities of natural gas can be overcome by using hydrogen as additional fuel. In this paper, a comparison was carried out between methane and different CH4/H2 mixtures. Specifically, low levels of hydrogen addition were used (5%, 10%, 20% volumetric basis) in stoichiometric and lean burn conditions. The measurements were carried out in an optically accessible single-cylinder port fuel injection spark ignition engine. Optical measurements were performed to analyze the combustion process with high spatial and temporal resolution. In particular, optical techniques based on 2D-digital imaging with two different combustion chamber views were used. Macroscopic (global) and microscopic (local) post-processing tools were implemented to provide a detailed analysis of the flame front propagation process. Moreover, an in-depth analysis was performed to study the flame penetration in the piston top-land crevice. Exhaust gas emissions were also characterized and linked with thermodynamic and optical data. In order to evaluate the combustion process in similar fluid-dynamic conditions, all measurements were performed under steady-state conditions at fixed engine speed, load and spark advance. All the results highlight fast combustion promotion due to the hydrogen addition. In addition, hydrogen reduces the preferential propagation of the flame in a certain direction and increases the flame front wrinkling. Flame propagation in the top-land crevice region was measured for methane and its blends with hydrogen, which represents an original contribution to the literature. An inverse trend was seen between flame penetration in the crevice and unburned hydrocarbon emissions. Lastly, tests in lean conditions demonstrate the potential to decrease nitrogen oxides emissions when methane and methane-hydrogen blends are used.
关键词： Methane,SI engines,Crevice,Optical analysis,Hydrogen
更新于2025-09-09 09:28:46