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- 2018
- Solar Photovoltaic (SPV)
- Fuzzy Logic Control (FLC)
- MATLAB/Simulink
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- Electrical Engineering and Automation
- Cochin University College of Engineering
- T.K.M College of Engineering
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Crystallite size and microstrain: XRD line broadening analysis of AgSiN thin films
摘要： Purpose – This paper aims to determine the crystallite size and microstrain values of AgSiN thin films using potential approach called approximation method. This method can be used as a replacement for other determination methods such as Williamson-Hall (W-H) plot and Warren-Averbach analysis. Design/methodology/approach – The monolayer AgSiN thin films on Ti6Al4V alloy were fabricated using magnetron sputtering technique. To evaluate the crystallite size and microstrain values, the thin films were deposited under different bias voltage ((cid:1)75, (cid:1)150 and (cid:1)200 V). X-ray diffraction (XRD) broadening profile along with approximation method were used to determine the crystallite size and microstrain values. The reliability of the method was proved by comparing it with scanning electron microscopy graph and W-H plot method. The second parameters’ microstrain obtained was used to project the residual stress present in the thin films. Further discussion on the thin films was done by relating the residual stress with the adhesion strength and the thickness of the films. Findings – XRD-approximation method results revealed that the crystallite size values obtained from the method were in a good agreement when it is compared with Scherer formula and W-H method. Meanwhile, the calculations for thin films corresponding residual stresses were correlated well with scratch adhesion critical loads with the lowest residual stress was noted for sample with lowest microstrain and has thickest thickness among the three samples. Practical implications – The fabricated thin films were intended to be used in antibacterial applications. Originality/value – Up to the knowledge from literature review, there are no reports on depositing AgSiN on Ti6Al4V alloy via magnetron sputtering to elucidate the crystallite size and microstrain properties using the approximation method.
关键词： AgSiN thin films,XRD-approximation method,Microstrain,Crystallite size
更新于2025-09-23 15:21:01
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Ultra high birefringence and lower beat length for square shape PCF: Analysis effect on rotation angle and eccentricity
摘要： In this article, a circular air hole organized in a square manner cladding with porous core using elliptical holes index-guiding photonic crystal fiber (IG-PCF) has been proposed and numerically examined. The numerical study is obtained by using finite element method (FEM) inclusion with an electromagnetic absorption boundary perfectly matched layer (PML). Investigation process runs over a broader wavelength range near IR region from 1.20 mm to 1.80 mm for evaluating modal properties of proposed square shaped PCF. S-PCF expresses higher birefringence (2.2 (cid:1) 10(cid:3)3), high nonlinearity (23.46 W(cid:3)1 km(cid:3)1) along with lower beat length (553.86 mm) at the pumping wavelength k = 1.20 mm. Core holes angle orientation and eccentricity are tuned for gaining higher birefringence. Furthermore, beat length, Veff, spot size, beam divergence are inquired in details. Finally, this research is focused on birefringence and nonlinearity behaviors are highly affected by angle effect and eccentricity.
关键词： Beat length,Birefringence,Nonlinearity,Single mode PCF,Eccentricity,Spot size
更新于2025-09-23 15:21:01
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[IEEE 2018 12th France-Japan and 10th Europe-Asia Congress on Mechatronics - Tsu, Japan (2018.9.10-2018.9.12)] 2018 12th France-Japan and 10th Europe-Asia Congress on Mechatronics - Potentials of Galilean and Keplerian Liquid Crystal Zoom Lens System
摘要： This paper focuses on a non-mechanical zoom lens system using Liquid Crystal (LC). The LC lens cell is well known as an optical device of which the focal length can change non-mechanically as a lens by small electric power. The authors apply the two LC lens cells for composing the zoom lens system in which the magnification can change continuously in this paper. As two representative types of the telescopic lens, the Keplerian and the Galilean are famous. The former combines two convex lenses, while the latter combines a convex lens and a concave lens. The range of the focal length of which the LC lens cell can change is definite. It depends on the lens power, which is defined as an inverted value of the focal length. In this study, potential performances of the magnification range as the zoom lens, from the minimum to the maximum, have been estimated by simulation, comparing between the Keplerian and Galilean types. In addition, requirements of the lens power of the LC lens has been estimated. The authors have also discussed their smallest realizable size of the LC zoom lens system from the above simulation results.
关键词： Keplerian,the smallest size,potential performance,non-mechanical zoom lens,Galilean,liquid crystal zoom lens
更新于2025-09-23 15:21:01
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Digital holographic sizer for coal powder size distribution measurement: preliminary simulation and experiment
摘要： On-line and continuous measurements of coal powder size distribution in coal-fired plants remain challenging. A coal powder size measurement system based on digital holography (DH) is developed. The effects of several factors, i.e. pixel size, recording distance, particle size, and concentration, on particle size measurement by the DH method are quantified by simulation, yielding the suitable pixel size, recording distance and particle concentration. The measurement system is implemented based on the simulation results and applied to measure particle size distribution of pulverized coal samples. Results show that the particles are clearly reconstructed from the hologram, and the measured size distributions agree well with those of the samples measured by laser particle size analyzer. This work shows that the digital holographic sizer has great potential in coal powder size distribution measurement in power plant pipes.
关键词： digital holography,particle size distribution,coal powder,on-line measurement
更新于2025-09-23 15:21:01
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Determination of the two-dimensional distributions of gold nanorods by multiwavelength analytical ultracentrifugation
摘要： Properties of nanoparticles are influenced by various parameters like size, shape or composition. Comprehensive high throughput characterization techniques are urgently needed to improve synthesis, scale up to production and make way for new applications of multi-dimensional particulate systems. In this study, we present a method for measuring two-dimensional size distributions of plasmonic nanorods in a single experiment. Analytical ultracentrifuge equipped with a multiwavelength extinction detector is used to record the optical and sedimentation properties of gold nanorods simultaneously. A combination of sedimentation and extinction properties, both depending on diameter and length of the dispersed nanorods, is used to measure two-dimensional distributions of gold nanorod samples. The length, diameter, aspect ratio, volume, surface and cross-sectional distributions can be readily obtained from these results. As the technique can be extended to other non-spherical plasmonic particles and can be used for determining relative amounts of particles of different shapes it provides complete and quantitative insights into particulate systems.
关键词： gold nanorods,nanoparticles,multiwavelength extinction detector,two-dimensional size distributions,analytical ultracentrifugation
更新于2025-09-23 15:21:01
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Annealing of Gadolinium-Doped Ceria (GDC) Films Produced by the Aerosol Deposition Method
摘要： Solid oxide fuel cells need a diffusion barrier layer to protect the zirconia-based electrolyte if a cobalt-containing cathode material like lanthanum strontium cobalt ferrite (LSCF) is used. This protective layer must prevent the direct contact and interdiffusion of both components while still retaining the oxygen ion transport. Gadolinium-doped ceria (GDC) meets these requirements. However, for a favorable cell performance, oxide ion conducting films that are thin yet dense are required. Films with a thickness in the sub-micrometer to micrometer range were produced by the dry room temperature spray-coating technique, aerosol deposition. Since commercially available GDC powders are usually optimized for the sintering of screen printed films or pressed bulk samples, their particle morphology is nanocrystalline with a high surface area that is not suitable for aerosol deposition. Therefore, different thermal and mechanical powder pretreatment procedures were investigated and linked to the morphology and integrity of the sprayed films. Only if a suitable pretreatment was conducted, dense and well-adhering GDC films were deposited. Otherwise, low-strength films were formed. The ionic conductivity of the resulting dense films was characterized by impedance spectroscopy between 300 ?C and 1000 ?C upon heating and cooling. A mild annealing occurred up to 900 ?C during first heating that slightly increased the electric conductivity of GDC films formed by aerosol deposition.
关键词： room temperature impact consolidation (RTIC),crystallite size,dense films,thermal powder treatment,electrical conductivity
更新于2025-09-23 15:21:01
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Fluorescent Nanodiamonds || Producing Fluorescent Nanodiamonds
摘要： Natural diamonds in colors are commonly known as fancies, or fancy color diamonds, in gemstone industries. They are rare, beautiful, and some even carry impressive price tags in the jewelry market. By comparison, micro‐ and nanoscale diamond powders are low in price, with or without colors and fluorescent or not. These powders have been used as abrasives for grinding and polishing purposes since ancient time, mainly because of their extraordinary hardness. Little or no attention has been paid over the centuries to other properties of nanodiamonds such as their innate biocompatibility and light‐emitting capability. The invention of fluorescent nanodiamond (FND) in 2005 has revolutionized the field, opening a new area of research and development with diamonds. Experiments with FNDs in the last decade have demonstrated various promising applications of surface‐functionalized FNDs in diversified fields, ranging from physics and chemistry to biology and medicine. It is worthy of noting that as originated from the discovery of Radium by Marie Sk?odowska Curie (Section 3.2), FNDs may very well be called Madame Curie’s gemstones, valued appropriately as a scientist’s best friend.
关键词： fluorescent nanodiamonds,magnetically modulated fluorescence,fluorescence lifetime,size reduction,FND,ion irradiation,H3 centers,nitrogen-vacancy centers,electron irradiation,NV centers
更新于2025-09-23 15:21:01
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Grain size dependence of tensile properties in nanocrystalline diamond
摘要： Nanocrystalline diamond (NCD) is a promising material due to its extraordinary mechanical properties, however, the research on the dependence of mechanical properties on the grain size (d) of NCD is still limited. In this paper, the mechanical behavior of 3D NCD with various d is investigated using molecular dynamics (MD) simulations. It was found that the mechanical properties of NCD are sensitive to d. The Young's modulus (E) increases with the increase of d due to the increasing fraction of grain interiors (GIs), while the failure strain (εf) decreases with the increase of d due to the decreasing fraction of grain boundaries (GBs). It was also found that the failure strength (σf) decreases with the increase of d, which could be attributed to that for larger d the stress concentration in the GBs is severer, which may make cracks initiate more easily. Similar to εf and σf, the deformation work density was found to increase with the decrease of d, indicating the enhancement of toughness of NCD when d is small. For the samples of different d, the nucleation and propagation of both transgranular and intergranular cracks are the main failure mechanisms, which is consistent with experimental observations.
关键词： Molecular dynamics simulation,Mechanical property,Nanocrystalline diamond,Tension,Grain size
更新于2025-09-23 15:21:01
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Stopband-Extended and Size-Miniaturized Low-Pass Filter with Three Transmission Zeros
摘要： This paper presents a compact structure composed of an upper high-impedance transmission line, a middle extended parallel coupled line, and a pair of inter-coupled symmetrical stubs. Detailed investigation into this structure based on an equivalent circuit analysis reveals that this proposed structure exhibits a quasi-elliptic low-pass filtering response with three transmission zeros. Moreover, the positions of the three transmission zeros can be tuned and reallocated flexibly by choosing the proper circuit parameters. Finally, the design concept is validated through the design, fabrication, and measurement of two exemplary low-pass filters (LPFs) with one single unit and two cascaded asymmetric units. The measured results agree well with the simulated results. In addition, in the range of 1.42 fc to 7.03 fc, the fabricated quasi-elliptic LPFs experimentally demonstrate a very wide upper-stopband of 20 dB using a compact size of only 0.0089λg2, where λg is the guided wavelength of a 50 ? transmission line at the central frequency.
关键词： transmission zero,Low-pass filter (LPF),compact size,wide stopband
更新于2025-09-23 15:21:01
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Metallic Nanomaterials (Part A) || 5. Synthesis and characterization of size-controlled atomically precise gold clusters
摘要： In this article, synthetic strategies and characterization methodologies of atomically precise gold clusters have been summarized. The typical and effective synthetic strategies including a systematic “size-focusing” methodology has been developed for attaining atomically precise gold clusters with size control. Another universal synthetic methodology is ligand exchange-induced size/structure transformation (LEIST) based on from one stable size to another. These two methodologies have largely expanded the “universe” of atomically precise gold clusters. Elite of typical synthetic case studies of ligand protected gold clusters are presented. Important characterization techniques of these atomically precise gold clusters also are included. The identification and characterization of gold clusters have been achieved in terms of nuclearity (size), molecular formulation, and geometrical structures by the combination of these techniques. The determination of gold cluster structure based on single crystals is of paramount importance in understanding the relationship of structure–property. The criterion and selection of these typical gold clusters are all “strictly” atomically precise that all have been determined ubiquitously by single crystal diffraction. These related crystallographic data are retrieved from Cambridge Crystallographic Data Centre (CCDC) up to 30th November 2017. Meanwhile, the cutting edge and other important characterization methodologies including electron diffraction (ED), extended X-ray absorption fine structure (EXFAS), and synchrotron sources are briefly reviewed. The new techniques hold the promise of pushing the limits of crystallization of gold clusters. This article is not just an exhaustive and up to date review, generally summarized synthetic strategies, but also a practical guide regarding gold cluster synthesis. We called it a “Cookbook” of ligand protected gold clusters, including synthetic recipes and characterization details.
关键词： alkyne,ligand exchange-induced size/structure transformation,phosphine,“size-focusing” methodology,size-controlled synthesis,thiolate,gold cluster
更新于2025-09-23 15:19:57