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Investigation of Milling of Carbon Fiber Reinforced Plastic

glass fiber reinforced polymer (GFRP) composite materials. Defence Technology, 14/4. (2018) 318–326. https://doi.org/10.1016/j.dt.2018.02.001 [4] Mathivanan N. R., Mahesh B. S., Shetty, H. A.: An experimental investigation on the process parameters influencing machining forces during milling of carbon and glass fiber laminates. Measurement, 91. (2016) 39–45. https://doi.org/10.1016/j.measurement.2016.04.077 [5] Wang H., Sun J., Li J., Lu L., Li N.: Evaluation of cutting force and cutting temperature in milling carbon fiber-reinforced polymer

Open access
Role of the Features of Focused Laser Beam at Pulsed Laser Cutting

2014 (ICRM). Procedia CIRP, 20. (2014) 98–102. https://doi.org/10.1016/j.procir.2014.05.037 [9] Hashemi S. S., Sabouri S. G., Khorsandi A.: I n situ measurement of laser beam quality. Applied Physics B, (2017) 123–233. https://doi.org/10.1007/s00340-017-6811-y [10] MSZ EN ISO 1145 Optika és fotonika. Lézerek és lézerberendezések. Szakszótár és jelképek (ISO 1145:2018) [11] Buza G.: Lézersugaras technológiák I. Edutus Főiskola, 2012. 24–29. [12] Meszlényi Gy., Dobránszky J., Puskás Zs.: Laser cutting of high precision tubes . Material

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Analysis of Recrystallization Peak Occuring During DSC Measurement

Abstract

Severe plastic deformation (SPD) is a well-established methodology for the processing of bulk ultrafine grained materials. Among various methods, equal channel angular pressing (ECAP) is the most popular way of creating ultrafine grained materials. The stored energy after ECAP in these substances highly influences the microstructural processes: recovery and recrystallization of the processed materials. We analyzed the recrystallization kinetics of room and elevated temperature ECAP processed copper samples using differential scanning calorimetry (DSC). For the processing of the measurement data we developed a MATLAB processing routine.

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Role of RF power on physical properties of RF magnetron sputtered GaN/p-Si(1 0 0) thin film

T.T.A., L i C.-C., Y en W.-C., Materials Science and Engineering: B , 193 (2015), 13. [41] B iswas A., B hattacharyya D., S ahoo N.K., Y adav B.S., M ajor S.S., S rinivasa R.S., Journal of Applied Physics , 103 (2008), 083541. [42] S elman A.M., H assan Z., H usham M., Measurement , 56 (2014), 155. [43] S chulz H., T hiemann K.H., Solid State Communications , 23 (1977), 815. [44] Y eh C.-Y., L u Z.W., F royen S., Z unger A., Physical Review B , 46 (1992), 10086. [45] O rak I., K ocyigit A., T urut A., Journal

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Investigation of the structural, optical and photoluminescence properties of electrosynthesized hexagonal nanocrystalline Cd0.3Zn0.7S thin film

Abstract

In this paper, Cd0.3Zn0.7S thin film has been electrodeposited from aqueous bath containing CdSO4, ZnSO4, Na2S2O3 and EDTA, having pH ~ 14. The structural, optical, morphological, surface wettability and photoluminescence properties of the film were investigated. The XRD pattern showed that the film consisted of mixed phases of CdS and ZnS with polycrystalline structure. The bandgap of the film was evaluated as 2.69 eV. The AFM study revealed that the Cd0.3Zn0.7S thin film contained spherical grains with root mean square roughness of 6.09 nm. The water contact angle measurement showed that the thin film was hydrophilic in nature. Moreover, the PL study revealed that the excitation wavelength was 460 nm.

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Deposition time and annealing effects on morphological and optical properties of ZnS thin films prepared by chemical bath deposition

Abstract

Nanocrystalline zinc sulfide thin films were prepared on glass substrates by chemical bath deposition method using aqueous solutions of zinc chloride, thiourea ammonium hydroxide along with non-toxic complexing agent trisodium citrate in alkaline medium at 80 °C. The effect of deposition time and annealing on the properties of ZnS thin films was investigated by X-ray diffraction, scanning electron microscopy, optical transmittance spectroscopy and four-point probe method. The X-ray diffraction analysis showed that the samples exhibited cubic sphalerite structure with preferential orientation along 〈2 0 0〉 direction. Scanning electron microscopy micrographs revealed uniform surface coverage, UV-Vis (300 nm to 800 nm) spectrophotometric measurements showed transparency of the films (transmittance ranging from 69 % to 81 %), with a direct allowed energy band gap in the range of 3.87 eV to 4.03 eV. After thermal annealing at 500 °C for 120 min, the transmittance increased up to 87 %. Moreover, the electrical conductivity of the deposited films increased with increasing of the deposition time from 0.35 × 10−4 Ω·cm−1 to 2.7 × 10−4 Ω·cm−1.

Open access
Green synthesis and spectral analysis of surface encapsulated copper (II) oxide nanostructures

Abstract

Nanostructures of copper (II) oxide were synthesized through chemical reduction of copper (II) sulfate pentahydrate using phytochemicals present in leaf extracts of Leucas aspera. The crystalline phases and size were assessed by X-ray diffraction data analysis. From the Bragg reflection peaks, existence of monoclinic end-centered phase of copper (II) oxide along with presence of cubic primitive phase of copper (I) oxide and traces of cubic face centered lattices of zero valent copper was revealed. The three Raman active modes corresponding to CuO phase were identified in the sample with permissible merging of characteristic bands due to nanostructuring and organic capping. The surface topography measurement using field emission scanning electron microscope evidenced the occurrence of cylindrical rod shaped morphological structures along with a number of unshaped aggregates in the sample. The effective crystallite size and lattice strain were estimated from Williamson-Hall analysis of Bragg reflection data. Tauc plot analysis of UV-Vis-NIR absorption data in direct transition mode provided an estimation of band gap, viz. 1.83 eV and 2.06 eV respectively, for copper (II) oxide and copper (I) oxide. Thermal degradation study using thermogravimetric curve analysis could reveal the amount of moisture content, volatile components as well as the polymer capping over nanorods present in the sample. It could be seen that upon heating, inorganic core crystals undergo oxidation process and at temperature above 464 °C, the sample was found to be composed solely of inorganic crystallite phase of copper (II) oxide.

Open access
Investigation, analysis and comparison of current-voltage characteristics for Au/Ni/GaN Schottky structure using I-V-T simulation

Abstract

In this work, we have presented a theoretical study of Au/Ni/GaN Schottky diode based on current-voltage (I-V) measurement for temperature range of 120 K to 400 K. The electrical parameters of Au/Ni/GaN, such as barrier height (Φb), ideality factor and series resistance have been calculated employing the conventional current-voltage (I-V), Cheung and Chattopadhyay method. Also, the variation of Gaussian distribution (P (Φb)) as a function of barrier height (Φb) has been studied. Therefore, the modified ((ln(I0T2)(q2σs022kT2)=ln(AA*)qB0kT)vs.(1kT)) relation has been extracted from (I-V) characteristics, where the values of ΦB0 and ASimul* have been found in different temperature ranges. The obtained results have been compared to the existing experimental data and a good agreement was found.

Open access
Optimization and characterization of NiO thin films prepared via NSP technique and its P-N junction diode application

Abstract

The present work reports on the optimization of substrate temperature, molar concentration and volume of the solution of nickel oxide (NiO) thin films prepared by nebulizer spray pyrolysis (NSP) technique. NiO films were optimized and characterized by XRD, SEM, EDX, UV-Vis and I-V measurements. Based on XRD analysis, the molar concentration, volume of solution and substrate temperature of the prepared NiO films were optimized as 0.20 M, 5 mL and 450 °C for P-N diode applications. The XRD pattern of the optimized NiO film revealed cubic structure. The surface morphological variations and elemental composition were confirmed by SEM and EDX analysis. The optical properties were studied with UV-Vis spectrophotometer and the minimum band gap value was 3.67 eV for 450 °C substrate temperature. Using J-V characteristics, the diode parameters: ideality factor n and barrier height Φb values of p-NiO/N-Si diode prepared at optimum conditions, i.e. 450 °C, 0.2 M, 5 mL, were evaluated in dark and under illumination.

Open access
Development of sol-gel derived gahnite anti-reflection coating for augmenting the power conversion efficiency of polycrystalline silicon solar cells

aoufi D., Mater. Res. Express., 6 (2018), 016417. [28] K esmez O., A karsu E., C amurlu H.E., Y avuz E., A karsu M., A rpac E., Ceram. Int., 44 (2018), 3183-3188. [29] J ung J., J annat A, A khtar M.S., Y ang O., J. Nanosci. Nanotechnol., 18 (2018), 1274-1278. [30] R adziemska E., Renew. Energ., 28 (2003), 1. [31] D ubey S., S arvaiya J.N., S eshadri B., Energy Procedia, 33 (2013), 311. [32] K umar J, N egi V.S., C hattopadhyay K.D., S arepaka R.V., S inha R.K., Measurement, 102 (2017) 96.

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