Journal articles on the topic 'Electron-optic parameters'
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1
Huang, Kai, Hideyuki Kotaki, Michiaki Mori, Yukio Hayashi, Nobuhiko Nakanii, and Masaki Kando. "Single-Shot Electro-Optic Sampling on the Temporal Structure of Laser Wakefield Accelerated Electrons." Crystals 10, no. 8 (July 24, 2020): 640. http://dx.doi.org/10.3390/cryst10080640.
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Particle acceleration driven by a high power Ti: sapphire laser has invoked great interest worldwide because of the ultrahigh acceleration gradient. For the aspect of electron acceleration, electron beams with energies over GeV have been generated using the laser wakefield acceleration mechanism. For the optimization of the electron generation process, real-time electron parameter monitors are necessary. One of the key parameters of a high energy particle beam is the temporal distribution, which is closely related with the timing resolution in a pump-probe application. Here, we introduced the electro-optic sampling method to laser wakefield acceleration. Real-time multibunch structures were observed. Careful calculations on the physical processes of signal generation in an electro-optic crystal were performed. Discussions of the methodology are elaborated in detail.
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BISTI, V. E. "MAGNETOPLASMONS IN SYMMETRY DRIVEN BILAYER ELECTRON SYSTEM." International Journal of Modern Physics B 21, no. 08n09 (April 10, 2007): 1555–57. http://dx.doi.org/10.1142/s021797920704318x.
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The effect of space symmetry on magnetoplasmon charge density excitations in a weekly tunnel coupled bilayer electron system is considered. The magnetic field corresponds to the filling factor ν = 4. The energy of optic magnetoplasmon is not affected by space symmetry. Three other collective magnetoplasmon modes are determined by relations between parameters of asymmetry, tunnel parameter and energy of acoustic plasmon.
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Thomas, Jeena, Prakash Perikaruppan, Vinoy Thomas, Jancy John, Raji Mary Mathew, Joice Thomas, Ibrahimkutty Rejeena, Sebastian Mathew, and Abdulhassan Mujeeb. "Green Synthesized Plasmonic Silver Systems for Potential Non-Linear Optical Applications: Optical Limiting and Dual Beam Mode Matched Thermal Lensing." Australian Journal of Chemistry 72, no. 6 (2019): 460. http://dx.doi.org/10.1071/ch18617.
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Bioactive compound functionalized plasmonic systems are evolving as a promising branch of nanotechnology. In this communication the synthesis of bioactive compound mimosine-based silver nanoparticles (AgNPs) and their non-linear optical and thermo-optic properties are presented. UV-Visible spectroscopy, optical bandgap measurement, fluorescence spectroscopy, and high-resolution transmission electron microscopy (HRTEM) techniques were used to characterize the synthesized AgNPs. An open aperture z-scan technique was used to determine the non-linear optical parameters. A very strong reverse saturable absorption (RSA) and low optical limiting threshold were observed for the present mimosine decorated AgNP system. The thermo-optic property of the present system was evaluated using a highly sensitive dual beam mode matched thermal lensing spectroscopic technique. A comparison of the low limiting threshold (242MWcm−2) and thermo-optic property (thermal diffusivity, D=1.13×10−7m2s−1) with similar systems proves its capability for non-linear optical and thermo-optic applications.
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ARABSHAHI, HADI. "CALCULATION OF THE ELECTRON DRIFT MOBILITY IN Cr2+:ZnS AND Cr2+:ZnSe MATERIALS BY RODE ITERATION MODEL." International Journal of Modeling, Simulation, and Scientific Computing 01, no. 04 (December 2010): 469–75. http://dx.doi.org/10.1142/s1793962310000262.
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The results of electron drift velocity in Cr2+:ZnS , and Cr2+:ZnSe are calculated for different temperatures, free-electron concentrations and compositions. The two-mode nature of the polar optic phonons is considered jointly with deformation potential acoustic, piezoelectric, alloy and ionized-impurity scattering. Band non-parabolocity, admixture of p functions, arbitrary degeneracy of the electron distribution, and the screening effects of free carriers on the scattering probabilities are incorporated. The Boltzmann equation is solved by an iterative technique using the currently established values of the material parameters. The iterative results are in fair agreement with other recent calculations obtained using the relaxation-time approximation and experimental methods.
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Qi, Guochen, Di Tian, Guolun Gao, Guangda Liu, Chunling Qiu, and Tao Long. "Numerical Simulations and the Design of Magnetic Field-Enhanced Electron Impact Ion Source with Hollow Cylinder Structure." Journal of Analytical Methods in Chemistry 2020 (January 25, 2020): 1–7. http://dx.doi.org/10.1155/2020/2809485.
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An electron impact ion source-adopted magnetic field-enhanced technology has been designed for enhancing the electron intensity and the ionization efficiency. Based on the ion optic focus mechanism, an electron impact ionization source was designed, and the electron entrance into the ionization chamber was designed with a hollow cylinder structure to improve the ion extraction efficiency. Numerical simulation and optimal geometry were optimized by SIMION 8.0 to provide higher electron intensity and ion transmission efficiency. To improve the electron intensity, the influence of the filament potential and magnetic intensity was investigated, and the values of 70 eV and 150 Gs were chosen in our apparatus. Based on the optimal parameters, the air in the lab and oxygen gas was detected by the homemade apparatus, and the ion intensity was detected in the positive and negative ion modes, respectively. The homemade electron impact ion source apparatus has the potential to enhance ionization efficiency applied in the mass spectrometer ionization source.
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Vintaikin, B. Е., O. V. Kondakov, and K. G. Ivanov. "Determining Anisotropic Material Properties by Means of Simulating Transmission in a Planar Waveguide." Herald of the Bauman Moscow State Technical University. Series Natural Sciences, no. 83 (2019): 51–63. http://dx.doi.org/10.18698/1812-3368-2019-2-51-63.
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The paper presents investigation results concerning a magneto-optic effect occurring in the far infrared range in bismuth. The investigation involves recording transmission in a planar waveguide located in a variable magnetic field. We ran a numerical simulation of the magneto-optic spectrum shapes in the relaxation-time approximation and determined a set of parameters for the electron energy spectrum in bismuth in the effective mass tensor approximation. We found that there is a discrete function describing how relaxation time and charge carrier concentration depend on the magnetic field magnitude. The function stems from the presence of electrons with different effective masses, which are concentrated in the three equivalent L points of the Brillouin zone, and holes in the T point of the Brillouin zone, which have topologically unconnected anisotropic constant energy surfaces
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DONG, HUI-NING, DAVID J. KEEBLE, and SHAO-YI WU. "THEORETICAL EXPLANATIONS OF THE SPIN HAMILTONIAN PARAMETERS FORCu2+ION INLaSrAl1-xCuxO4SOLID SOLUTION." International Journal of Modern Physics B 21, no. 18n19 (July 30, 2007): 3174–76. http://dx.doi.org/10.1142/s0217979207044123.
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It is of interest for layered oxides containing copper because they are related to high temperature superconductivity. Among them, LaSrAl1-xCuxO4solid solution has received much attention due to its elastic and elasto-optic properties and application as promising substrate for high- Tcsuperconducting thin films. So many theoretical and experimental works have been done to understand the several characteristics of the LaSrAl1-xCuxO4materials. In this paper, the electron paramagnetic resonance g factors g//, g⊥and hyperfine structure constants A//, A⊥for the tetragonal Cu2+center in LaSrAl1-xCuxO4solid solution are theoretically explained by the method of diagonalizing the full Hamiltonian matrix. The related crystal field parameters are calculated from the superposition model and the local structural parameters of the impurity Cu2+occupying the host Al3+site. The superposition model parameters used in this work are comparable with those for similar tetragonal ( CuO6)10-clusters in the previous works. The calculated results are in reasonable agreement with the observed values. The results are discussed.
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de La Rochefoucauld, Ombeline, Guillaume Dovillaire, Fabrice Harms, Mourad Idir, Lei Huang, Xavier Levecq, Martin Piponnier, and Philippe Zeitoun. "EUV and Hard X-ray Hartmann Wavefront Sensing for Optical Metrology, Alignment and Phase Imaging." Sensors 21, no. 3 (January 28, 2021): 874. http://dx.doi.org/10.3390/s21030874.
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For more than 15 years, Imagine Optic have developed Extreme Ultra Violet (EUV) and X-ray Hartmann wavefront sensors for metrology and imaging applications. These sensors are compatible with a wide range of X-ray sources: from synchrotrons, Free Electron Lasers, laser-driven betatron and plasma-based EUV lasers to High Harmonic Generation. In this paper, we first describe the principle of a Hartmann sensor and give some key parameters to design a high-performance sensor. We also present different applications from metrology (for manual or automatic alignment of optics), to soft X-ray source optimization and X-ray imaging.
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Erkan, Sultan, and Duran Karakaş. "A theoretical study on cyclometalated iridium (III) complexes by using a density functional theory." Journal of Theoretical and Computational Chemistry 19, no. 02 (March 2020): 2050006. http://dx.doi.org/10.1142/s0219633620500066.
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Cyclometalated iridium (III) complexes (Ir1–Ir4) are calculated in detail with computational chemistry methods. The calculated structural parameters of Ir3 are compared with experimental values and a good fit is obtained. IR spectra are calculated at B3LYP/LANL2DZ/6-31G(d) level in the gases phase. Calculated 1H-NMR chemical shift values of the mentioned complexes are compared with the experimental data and all chemical shifts are assigned to the respective atoms. The quantum chemical parameters such as absolute hardness ([Formula: see text]), absolute softness ([Formula: see text]) electronegativity ([Formula: see text]), chemical potential ([Formula: see text]) and electronic charges ([Formula: see text]) are calculated and are associated with the experimental anti-cancer properties of the related complexes. Nonlinear optic properties of the Ir1–Ir4 were investigated with the average linear polarizability ([Formula: see text]), the anisotropy of the polarizability ([Formula: see text]), first hyperpolarizability ([Formula: see text]) values. Hole transfer ([Formula: see text]), electron transfer integrals ([Formula: see text]), hole reorganization energies ([Formula: see text]) and electron reorganization energies ([Formula: see text]) are examined. In addition, molecular docking study was performed. It was found that the molecular docking results are similar to the experimental anti-cancer trend.
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Schroer, Christian G., and Gerald Falkenberg. "Hard X-ray nanofocusing at low-emittance synchrotron radiation sources." Journal of Synchrotron Radiation 21, no. 5 (August 29, 2014): 996–1005. http://dx.doi.org/10.1107/s1600577514016269.
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X-ray scanning microscopy relies on intensive nanobeams generated by imaging a highly brilliant synchrotron radiation source onto the sample with a nanofocusing X-ray optic. Here, using a Gaussian model for the central cone of an undulator source, the nanobeam generated by refractive X-ray lenses is modeled in terms of size, flux and coherence. The beam properties are expressed in terms of the emittances of the storage ring and the lateral sizes of the electron beam. Optimal source parameters are calculated to obtain efficient and diffraction-limited nanofocusing. With decreasing emittance, the usable fraction of the beam for diffraction-limited nanofocusing experiments can be increased by more than two orders of magnitude compared with modern storage ring sources. For a diffraction-limited storage ring, nearly the whole beam can be focused, making these sources highly attractive for X-ray scanning microscopy.
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Bubnoff, Dimitry V., Mariana M. O. Carvalho, José Adilson de Castro, and Thiago R. M. Lourenço. "Kinetic Study on Martensite Formation in Steels 1045 and 4340 under Variable Cooling Rates." Materials Science Forum 869 (August 2016): 550–55. http://dx.doi.org/10.4028/www.scientific.net/msf.869.550.
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The experiments were carried with two steels with different chemical compositions, aiming at understanding and comparison with the available literature. The microstructures of steels 1045 and 4340 were characterized and quantified using scanning electron microscopy (SEM) and optic microscopy (OM) with quantitative methods. Based on the experimental results, the amount of martensite, the hardness and the microhardness were determined, as a function of the distance from the quenching end, under different cooling conditions. For predicting the evolution of martensitic fraction along the sample, Koistinen-Marburger’s (K-M) model was adopted. It was found that the parameters recommended in the literature for the traditional K-M model do not represent accurately the results obtained for the steel samples under investigation. According to indications found in recent literature, parameter corrections were proposed, leading to a modified K-M model which better represents the transformations observed in the different examined steels.
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Singh, Shalini, Karthick Subramaniam, Nishita Chittora, A. Brolin, and IA Palani. "Studies on development of NiTi-integrated optical fiber sensor and its life cycle behavior." Journal of Intelligent Material Systems and Structures 31, no. 6 (February 17, 2020): 869–81. http://dx.doi.org/10.1177/1045389x20905969.
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Shape memory alloy coating on an optical fiber plays an important role in developing novel active thermal sensors in the field of microelectromechanical systems. In this article, a detailed analysis of NiTi alloy deposited over plastic optical fiber was discussed. A detailed investigation of the morphological, structural, and thermal properties of the NiTi-coated optic fiber was conducted. The uniformity, crystallinity, transformation temperatures, and thermal stability of the coatings were measured using differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis, respectively. Also, an electrical actuation setup thermo-mechanical test was conducted through Joule heating in which different voltages at varying loads have been used. The sensor characteristic–based parameters (time response and sensitivity) were also calculated. The article presents a complete analysis of experimental results showing the properties and performances of the plastic optical fiber after coating with shape memory alloy.
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Güneri, Emine. "The Role of Au Doping on the Structural and Optical Properties of Cu2O Films." Journal of Nano Research 58 (June 2019): 49–67. http://dx.doi.org/10.4028/www.scientific.net/jnanor.58.49.
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The changes in structural and optical properties of the Cu2O films obtained on the glass with different concentrations of Au by the chemical bath method were studied in this work. Lattice parameter, crystal size, preferential orientation and surface tension of the films were calculated using X-ray diffraction data which showed that all of the films were in polycrystalline form. It was determined that the structural parameters of all films were changed with the doping ratio. The surface morphology of the films was imaged using a field emission scanning electron microscope. The optical properties of the films were discovered using the optic spectrometer. Changes in the optical properties were discovered as a function of Au ratio. It was determined that the energy band gap value (2.12 eV-2.02 eV), the refractive index, the extinction coefficient, the real and dielectric coefficients, the optical conductivity, and the skin depth of films varied with Au doping ratio.
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Gheorghe, Dan, M. Schwartz, Ion Ciuca, and Robert Ciocoiu. "A Comparative Microstructure Evolution of AISI H21 and Inconel 718 in Cyclic Heating." Materiale Plastice 55, no. 3 (September 30, 2018): 454–59. http://dx.doi.org/10.37358/mp.18.3.5050.
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The AISI H21 steel used for dies in copper hot extrusion softened only after several runs. To improve production parameters a new material was necessary for the die, and, as a first choice, Inconel 718 was preferred. Prior to adopting this material for new extrusion dies an experimental program with temperature exposure cycles was performed so as to study microstructure evolution within AISI H21 and Inconel 718. The samples were studied by optic and scanning electron microscopy (SEM) and were also submitted to X-ray diffraction (XRD) and microhardness tests. The results showed carbide coalescence, which led to softening, followed by a re-precipitation in the steel, while, in Inconel 718, the precipitation (in small amounts) of delta (ä) phase was observed.Using these results and combining them with practical experience with steel, we could predict that the Inconel 718 die performance is such that at least a double quantity of copper could be extruded per die.
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Papan, Jelena, Patricija Hribar Hribar Boštjančič, Alenka Mertelj, and Darja Lisjak. "Preparation of Barium-Hexaferrite/Gold Janus Nanoplatelets Using the Pickering Emulsion Method." Nanomaterials 11, no. 11 (October 22, 2021): 2797. http://dx.doi.org/10.3390/nano11112797.
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Janus particles, which have two surfaces exhibiting different properties, are promising candidates for various applications. For example, magneto-optic Janus particles could be used for in-vivo cancer imaging, drug delivery, and photothermal therapy. The preparation of such materials on a relatively large scale is challenging, especially if the Janus structure consists of a hard magnetic material like barium hexaferrite nanoplatelets. The focus of this study was to adopt the known Pickering emulsion, i.e., Granick’s method, for the preparation of barium-hexaferrite/gold Janus nanoplatelets. The wax-in-water Pickering emulsions were stabilized with a combination of cetyltrimethyl ammonium bromide and barium hexaferrite nanoplatelets at 80 °C. Colloidosomes of solidified wax covered with the barium hexaferrite nanoplatelets formed after cooling the Pickering emulsions to room temperature. The formation and microstructure of the colloidosomes were thoroughly studied by optical and scanning electron microscopy. The process was optimized by various processing parameters, such as the composition of the emulsion system and the speed and time of emulsification. The colloidosomes with the highest surface coverage were used to prepare the Janus nanoplatelets by decorating the exposed surfaces of the barium hexaferrite nanoplatelets with gold nanospheres using mercaptan chemistry. Transmission electron microscopy was used to inspect the barium-hexaferrite/gold Janus nanoplatelets that were prepared for the first time.
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Alavi Nia, Ali, and Ali Shirazi. "An investigation into the effect of welding parameters on fatigue crack growth rate and fracture toughness in friction stir welded copper sheets." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 232, no. 3 (December 11, 2015): 191–203. http://dx.doi.org/10.1177/1464420715620918.
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In the present study, the effect of various factors of friction stir welding including rotational and traverse speeds of tool and in fact, the amount of the heat transferred within welding was evaluated on the resistance to fatigue crack growth and fracture toughness in different zones of welding copper sheets. In order to better assess these two properties, other mechanical properties such as tensile strength and hardness were also studied and the microstructure of different zones of welds was investigated using optic and electron microscopies. By doing this study, it became clear that the less the heat transferred to the plunging during the welding process, the better properties the resulting welds will have which well justifies the use of cooling in this study. Transferring heat to plunging causes the growth of grains in various zones and can cause the fatigue crack growth in heat-affected zone to increase averagely about 4.2 times the base material for different Δ K. In contrast, the occurrence of dynamic recrystallization in the stir zone as well as fragmentizing and alignment of grains in this zone can increase the resistance to fatigue crack growth up to 9-fold the resistance of the base material. The other interesting result of this study was that although the properties of stir zone improve by increasing the number of welding passes, the properties of its weakest zone i.e. the heat-affected zone will decline.
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Petford-Long, Amanda K., A. Cerezo, and M. G. Hetherington. "Fabrication and characterization - by High Resolution Electron Microscopy and atom probe microanalysis - of Co-based metallic multilayer films." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 772–73. http://dx.doi.org/10.1017/s042482010017699x.
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The fabrication of multilayer films (MLF) with layer thicknesses down to one monolayer has led to the development of materials with unique properties not found in bulk materials. The properties of interest depend critically on the structure and composition of the films, with the interfacial regions between the layers being of particular importance. There are a number of magnetic MLF systems based on Co, several of which have potential applications as perpendicular magnetic (e.g Co/Cr) or magneto-optic (e.g. Co/Pt) recording media. Of particular concern are the effects of parameters such as crystallographic texture and interface roughness, which are determined by the fabrication conditions, on magnetic properties and structure.In this study we have fabricated Co-based MLF by UHV thermal evaporation in the prechamber of an atom probe field-ion microscope (AP). The multilayers were deposited simultaneously onto cobalt field-ion specimens (for AP and position-sensitive atom probe (POSAP) microanalysis without exposure to atmosphere) and onto the flat (001) surface of oxidised silicon wafers (for subsequent study in cross-section using high-resolution electron microscopy (HREM) in a JEOL 4000EX. Deposi-tion was from W filaments loaded with material in the form of wire (Co, Fe, Ni, Pt and Au) or flakes (Cr). The base pressure in the chamber was around 8×10−8 torr during deposition with a typical deposition rate of 0.05 - 0.2nm/s.
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Bucse, Ionela Gabriela, Olimpia Ghermec, Mariana Ciobanu, Christian Ghermec, and Claudiu Nicolicescu. "Effects of Heat Treatment on Strength Wear Sintered Alloy Steels." Advanced Materials Research 1128 (October 2015): 315–21. http://dx.doi.org/10.4028/www.scientific.net/amr.1128.315.
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This paper presents the results of experimental research on thermal treatment of alloyed sintered steels and much the development of Fe‒3Mn‒1Mo‒1.5Cr‒0.5B‒0.45Graphite powder using mechanical alloying (MA). It was analyzed the influence of MA time on the morphology of the compound by electron microscopy SEM. The research has followed the study of the particle size powder mixtures influence obtained by mechanical alloying, compaction parameters and sintering process on the chemical and structural characteristics of the alloyed sintered steels. Thus there were compacted samples at 600, 700 and 800 MPa. The samples were heated using argon at a temperature of 1150°C using 60 minutes as a maintaining time. Cooling to the room temperature was achieved using a speed of about 30°C/ minutes. With the resulting steels, we have made metallographic determinations using optic microscopy and determinations of the main mechanical properties. Heat treatment took place (heating at 960°C and cooling in the H2O solution and 10% NaCl) in order to improve the properties of alloyed sintered steel hardness and strength. Specimens quenched and tempered have high wear coefficient compared with specimens as-sintered.
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Karim, Mohammad Farid Abd, Marlia Morsin, Suratun Nafisah, Norhayati Abu Bakar, and Munirah Ab Rahman. "Designing of 3D Sensor Chamber for Plasmonic-based Toxic Sensor Detection." International Journal of Engineering & Technology 7, no. 4.30 (November 30, 2018): 194. http://dx.doi.org/10.14419/ijet.v7i4.30.22119.
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Plasmonic sensor implementing an optical phenomenon called Localized Surface Plasmon Resonance (LSPR) resulting from the interaction of free electron with electromagnetic field of light at the metal nanoparticles surface. In this study, the plasmonic sensor has been developed for toxic detection in solution form. This system consists of five components which are the light source, duplex fiber optic, sensor chamber, spectrometer and computer. The sensor chamber has been specially designed using SolidWork software and printed using 3D printer with polylactic acid (PLA) material. The sensing activity was done in the sensor chamber with a sliding drawer which is used to place the sensing material or sample. OceanView software was used to analyze the recorded spectrum from the spectrometer. For this project, the experiment of the plasmonic sensor was carried out using targeted analyte namely chlorpyrifos with deionized (DI) water was set as a reference medium. Gold nanoparticles with nanospheres shape used as sensing materials. The sensing parameters are based on changing its intensity and resonance peak position. This plasmonic sensor was compared with UV-VIS spectrometer data to make sure it standardize and function correctly. Besides, the sensing process toward different concentrations of chlorpyrifos from 7.15 mM to 28.60 mM have been done. As a conclusion, the plasmonic sensor was successfully developed for toxic detection in solution form.
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Liu, Yunpeng, Shuo Jiang, Xiaozhou Fan, and Yuan Tian. "Effects of Degraded Optical Fiber Sheaths on Thermal Aging Characteristics of Transformer Oil." Applied Sciences 8, no. 8 (August 19, 2018): 1401. http://dx.doi.org/10.3390/app8081401.
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With the development of fiber optic sensing technology, optical fiber sensors have been widely used in online monitoring of power transformers. To investigate the influence of aging fiber sheaths on transformer oil, two kinds of special optical fibers with thermoplastic polyester elastomer (TPEE) and poly tetra fluoroethylene (PTFE) as sheaths underwent thermally accelerated aging in transformer oil at 130 °C. The volume resistivity, dielectric dissipation factor (DDF), and breakdown voltage of the oil were measured to indicate insulation strength. The water content and acid value of the oil were measured and fitted to predict the aging tends. The thermal aging characteristics of the oil were quantitatively compared and results showed two kinds of optical fibers could exacerbate all the physical and chemical parameters of oil, and the TPEE sheath had a more significant impact on the oil. The reasons contributing to such phenomenon were analyzed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Both TPEE and PTFE were depolymerized in high-temperature transformer oils, producing water and small molecule hydrocarbon groups. The accumulation of small hydrocarbon groups promoted positive feedback of pyrolysis in the oil. The free hydrogen produced by oil pyrolysis increased the acidity of the oil, which in turn increased the solubility of the water produced by sheath depolymerization. The chain depolymerization of TPEE was more severe than that of PTFE, further exacerbating the deterioration of TPEE-containing oil.
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Signorile, Anna, Domenico De Rasmo, Antonella Cormio, Clara Musicco, Roberta Rossi, Francesco Fortarezza, Luigi Palese, et al. "Human Ovarian Cancer Tissue Exhibits Increase of Mitochondrial Biogenesis and Cristae Remodeling." Cancers 11, no. 9 (September 12, 2019): 1350. http://dx.doi.org/10.3390/cancers11091350.
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Ovarian cancer (OC) is the most lethal gynecologic cancer characterized by an elevated apoptosis resistance that, potentially, leads to chemo-resistance in the recurrent disease. Mitochondrial oxidative phosphorylation was found altered in OC, and mitochondria were proposed as a target for therapy. Molecular evidence suggests that the deregulation of mitochondrial biogenesis, morphology, dynamics, and apoptosis is involved in carcinogenesis. However, these mitochondrial processes remain to be investigated in OC. Eighteen controls and 16 OC tissues (serous and mucinous) were collected. Enzymatic activities were performed spectrophotometrically, mitochondrial DNA (mtDNA) content was measured by real-time-PCR, protein levels were determined by Western blotting, and mitochondrial number and structure were measured by electron microscopy. Statistical analysis was performed using Student’s t-test, Mann-Whitney U test, and principal component analysis (PCA). We found, in OC, that increased mitochondrial number associated with increased peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) and mitochondrial transcription factor A (TFAM) protein levels, as well as mtDNA content. The OC mitochondria presented an increased maximum length, as well as reduced cristae width and junction diameter, associated with increased optic atrophy 1 protein (OPA1) and prohibitin 2 (PHB2) protein levels. In addition, in OC tissues, augmented cAMP and sirtuin 3 (SIRT3) protein levels were observed. PCA of the 25 analyzed biochemical parameters classified OC patients in a distinct group from controls. We highlight a “mitochondrial signature” in OC that could result from cooperation of the cAMP pathway with the SIRT3, OPA1, and PHB2 proteins.
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Monteiro, M. R., A. R. P. Ambrozin, A. O. Santos, P. P. Contri, and S. E. Kuri. "Evaluation of Metallic Corrosion Caused by Alcohol Fuel and Some Contaminants." Materials Science Forum 636-637 (January 2010): 1024–29. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.1024.
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In the present work, it is evaluated the effect of water and other contaminants of alcohol fuel on the corrosion behavior of different materials, which can constitute vehicles, storage and transportation fuels systems. For such, 5 metallic materials (zamak, low-carbon steel, stainless steel, and two Al alloys) were chosen and 5 alcoholic solutions were prepared: anhydrous ethanol (AEAC; solution 1); hydrated ethanol (AEHC; solution 2); AEAC and water with some impurities (AEAC + 6 % “corrosive” water; solution 3); AEHC and water with some impurities (AEHC + 6 % “corrosive” water; solution 4); and, AEAC and tap water (AEAC + 6 % tap water; solution 5). The crevice corrosion was investigated in static immersion tests, which were carried out at 50 °C for 2 months. The evaluation of the corrosive process was carried out by visual inspection, weight loss, optic microscopy, and scanning electron microscopy (SEM). Also, some quality parameters of the alcoholic solutions (specific mass, alcoholic content, pH, and conductivity) was analyzed in order to determine the influence of corrosion of the materials on them. The results have shown that crevice corrosion of all materials mostly occurred in solutions 3-5, which had a high amount of water and impurities. Some corrosion rates in such solutions were 90-400 times higher than those obtained in AEAC and AEHC. Among the materials, zamak and carbon steel suffered severe corrosive attack. The physicochemical properties of alcoholic solutions employed in the tests also changed, mainly the increase of pH and conductivity was observed. Therefore, the results demonstrate that the quality control of alcohol fuel is essential in order to avoid the damage of engine parts and storage and transportation systems. Specially, water, sulphate, chloride and acetate content must be monitored.
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Wieloszynska, Aleksandra, and Robert Bogdanowicz. "Studies on optical transmittance of boron-doped nanocrystalline diamond films." Photonics Letters of Poland 10, no. 3 (October 1, 2018): 88. http://dx.doi.org/10.4302/plp.v10i3.844.
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Thickness is one of the most important parameters in many applications using thin layers. This article describes determination of the thickness of boron-doped nanocrystalline diamond (NCD) grown on fused silica glass. The spectroscopic measurement system has been used. A high refractive index (2.3 @ 550 nm) was achieved for NCD films. The thickness of the NCD samples has been determined from transmission spectrum. Full Text: PDF ReferencesZ. Li, S. Butun, K. Aydin, 'Large-area, lithography-free super absorbers and color filters at visible frequencies using ultrathin metallic films', ACS Photonics, vol. 2.2, pp. 183-188 2015. CrossRef L. Yu, D.D. Tune, C.J. Shearer, J.G. Shapter, 'Implementation of antireflection layers for improved efficiency of carbon nanotube–silicon heterojunction solar cells', Solar Energy, vol. 118, pp. 592-599, 2015. CrossRef D. Majchrowicz, Daria, et al., Nitrogen-Doped Diamond Film for Optical Investigation of Hemoglobin Concentration, Materials, vol. 11.1, pp. 109, 2018. CrossRef K.L. Konnerth, F.H. Dill, 'In-situ measurement of dielectric thickness during etching or developing processes', IEEE Transactions on Electron Devices, vol. 22.7, pp. 452-456, 1975. CrossRef Z.G. Hu, P. Prunici, P. Hess, K.H. Chen, 'Optical properties of nanocrystalline diamond films from mid-infrared to ultraviolet using reflectometry and ellipsometry', Journal of Materials Science: Materials in Electronics, vol. 18.1, pp. 37-41, 2007. CrossRef J. Adamczewska, et al., 'Procesy technologiczne w elektronice półprzewodnikowej', WNT, Warsaw, 1980.J.P. Dilger, L. R. Fisher, D. A. Haydon, 'A critical comparison of electrical and optical methods for bilayer thickness determination', Chemistry and Physics of Lipids, vol. 30.2-3, pp. 159-176, 1982. CrossRef M, Ficek, et al, 'Optical and electrical properties of boron doped diamond thin conductive films deposited on fused silica glass substrates', Applied Surface Science, vol. 387, pp. 846-856, 2016. CrossRef R. Bogdanowicz, et al, 'Opto-Electrochemical Sensing Device Based on Long-Period Grating Coated with Boron-Doped Diamond Thin Film', J. Opt. Soc. Korea, vol. 19, pp. 705-710, 2015. CrossRef M. Sobaszek, et al., 'Optical and electrical properties of ultrathin transparent nanocrystalline boron-doped diamond electrodes', Optical Materials, vol.42, pp. 24-34, 2015. CrossRef R. Bogdanowicz, et al, 'Improved surface coverage of an optical fibre with nanocrystalline diamond by the application of dip-coating seeding', Diamond and Related Materials, vol. 55, pp. 52-63, 2015. CrossRef Z.G. Hu, P. Hess, 'Optical constants and thermo-optic coefficients of nanocrystalline diamond films at 30–500oC', Applied physics letters, vol. 89.8: 081906, 2006. CrossRef
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Dong, Meiling, Xiufang Cui, Guo Jin, Haidou Wang, Lina Zhu, and Jinna Liu. "The mechanical and corrosion resistance properties of Ti/TiN multi-layer films produced by physical vapor deposition." Anti-Corrosion Methods and Materials 62, no. 3 (May 5, 2015): 149–55. http://dx.doi.org/10.1108/acmm-01-2015-1495.
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Purpose – The aim of the present paper is to investigate the mechanical performance of multi-layer films. With the wide application of optic and electronic thin-films, membrane materials and membrane technology have become one of the most active fields of research in contemporary materials science (Dumont et al., 1997). Multi-layer films have evolved as candidates for these applications because of their unique properties. TiN and Ti/TiN multi-layer films were fabricated using the DC magnetron sputtering method. A nano-indentation tester and electronic film distribution tester were utilized to evaluate the mechanical properties and residual stress of the films. The existence of interface effects on the mechanical properties and corrosion resistance of the films were analyzed. Design/methodology/approach – In this study, the Ti/TiN multi-layer films were fabricated using the DC magnetron sputtering method. The films were deposited on polished 45# steels. Ti was used as the sputtering target. Ar and N2 were applied as working and reactive gases, respectively. Surface morphology was measured using transmission electron microscopy. The composition was analyzed using D8 X-ray diffraction. Nano-indentation tests were performed using Nanoindenter G200 with a Berkovich indenter. A BGS 6341 electronic film stress distribution tester was used to measure the distribution of stress in the films. Findings – The film surface was very smooth and the structure was very dense. The elastic modulus and micro-hardness of Ti/TiN multi-layer films were smaller, compared to those of the TiN film. Furthermore, both of these parameters initially decreased and later increased, with a decrease in the modulation period. The residual stress in the film was compressive. The corrosion resistance properties of TiN films were the best in NaCl solution, less so in alkaline solution and worst in acid solution. For the Ti/TiN multi-layer films tested in an acid medium, the corrosion resistance performance was better when the modulation period was decreased to micron grade under exposure conditions at ambient temperature. Originality/value – In the present paper, the Ti/TiN multi-layer films were fabricated using PVD with different variations, and the influence on the performance of Ti/TiN multi-layer films due to each single layer period of TiN was studied. The findings should provide useful guidelines for the preparation of high quality Ti/TiN multi-layer thin films.
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Yang, Hexiong, Tommy Yong, and Robert T. Downs. "Ferrobobfergusonite, □Na2Fe2+5Fe3+Al(PO4)6, a new mineral of the bobfergusonite group from the Victory Mine, Custer County, South Dakota, USA." Canadian Mineralogist 59, no. 3 (May 1, 2021): 617–27. http://dx.doi.org/10.3749/canmin.2000064.
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ABSTRACT A new mineral species, ferrobobfergusonite, ideally □Na2Fe2+5Fe3+Al(PO4)6, has been found in the Victory Mine, Custer County, South Dakota, USA. It is massive and associated with ferrowyllieite, schorl, fillowite, arrojadite, quartz, and muscovite. Broken pieces of ferrobobfergusonite are blocky or tabular with single crystals up to 0.9 × 0.7 × 0.4 mm. No twinning or parting is observed macroscopically. The mineral is deep green-brown and transparent with a pale green-yellow streak and vitreous luster. It is brittle and has a Mohs hardness of ∼5, with perfect cleavage on {010}. The measured and calculated densities are 3.68(1) and 3.69 g/cm3, respectively. Optically, ferrobobfergusonite is biaxial (+), with α = 1.698 (2), β = 1.705 (2), γ = 1.727 (2) (white light), 2V (meas.) = 65(2)°, 2V (calc.) = 60°, with orientation of the optic axes α ∧ X = 16°, β = Y, with X = yellowish brown, Y = brown, and Z = deep brown. The dispersion is very strong with r > v. The calculated compatibility index based on the empirical formula is 0.017 (superior). An electron microprobe analysis yielded an empirical formula (based on 24 O apfu) of (Na1.72□1.28)Σ3.00(Fe2+3.50Mn0.89Mg0.44Ca0.13)Σ4.96(Fe3+0.77Al0.23)Σ1.00Al(PO4)6. Ferrobobfergusonite is isostructural with bobfergusonite, a member of the alluaudite supergroup. It is monoclinic, with space group P21/n and unit-cell parameters a = 12.7156(3), b = 12.3808(3), c = 10.9347(3) Å, β = 97.3320(10)°, and V = 1707.37(7) Å3. The crystal structure of ferrobobfergusonite contains six octahedral M (= Fe2+, Mg, Mn2+, Al, Fe3+) sites and five X (= Na, Mn2+, Ca) sites with coordination numbers between 6 and 8. The six MO6 octahedra share edges to form two types of kinked chains extending along [101], with one consisting of M1–M4–M5 linkages and the other of M2–M3–M6 linkages. These chains are joined by PO4 tetrahedra to form sheets parallel to (010), which are linked together through corner-sharing between PO4 tetrahedra and MO6 octahedra in the adjacent sheets, leaving open channels parallel to a, where the large X cations are situated. The M cations are strongly ordered over the six sites, with M1, M2, M3, and M4 being dominantly occupied by Fe2+, and M5 and M6 by Fe3+ and Al, respectively. Among the five X sites, the X1 site is filled with Mn2+ and Ca, whereas the X2–X5 sites are partially occupied by Na.
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Silva, Daniela, Catarina S. Monteiro, Susana O. Silva, Orlando Frazão, Joana V. Pinto, Maria Raposo, Paulo A. Ribeiro, and Susana Sério. "Sputtering Deposition of TiO2 Thin Film Coatings for Fiber Optic Sensors." Photonics 9, no. 5 (May 13, 2022): 342. http://dx.doi.org/10.3390/photonics9050342.
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Thin films of titanium dioxide (TiO2) and titanium (Ti) were deposited onto glass and optical fiber supports through DC magnetron sputtering, and their transmission was characterized with regard to their use in optical fiber-based sensors. Deposition parameters such as oxygen partial pressure, working pressure, and sputtering power were optimized to attain films with a high reflectance. The films deposited on glass supports were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Regarding the deposition parameters, all three parameters were tested simultaneously, changing the working pressure, the sputtering power, and the oxygen percentage. It was possible to conclude that a lower working pressure and higher applied power lead to films with a higher reflectance. Through the analysis of the as-sputtered thin films using X-ray diffraction, the deposition of both Ti and TiO2 films was confirmed. To study the applicability of TiO2 and Ti in fiber sensing, several thin films were deposited in single mode fibers (SMFs) using the sputtering conditions that revealed the most promising results in the glass supports. The sputtered TiO2 and Ti thin films were used as mirrors to increase the visibility of a low-finesse Fabry–Perot cavity and the possible sensing applications were studied.
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Patterson, J. D., Wafaa A. Gobba, and S. L. Lehoczky. "Electron mobility in n-type Hg1−xCdxTe and Hg1−xZnx Te alloys." Journal of Materials Research 7, no. 8 (August 1992): 2211–18. http://dx.doi.org/10.1557/jmr.1992.2211.
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We have calculated the mobility of electrons in n-type Mercury Cadmium Telluride (MCT) and compared it to a calculation of the mobility of electrons in n-type Mercury Zinc Telluride (MZT) with nearly the same energy gap and with the same number of donors and acceptors. We also compared the results of the MZT calculation with experiment. We found for equivalent energy gaps that the mobilities in the two compounds (MCT, MZT) were nearly the same. The calculations for both MCT and MZT were based on the best set of material parameters that we could compile from the literature. Using these parameters, the comparison with experiment for MZT yielded good results. Since MZT is harder and structurally more stable with respect to Hg retention than MCT, the possibility of equivalent mobility for MCT and MZT is significant. This calculation is one of the first extensive calculations of the mobility of MZT, and we compared it with another which appeared to be less extensive. Our calculation involves scattering of the electrons by longitudinal optic phonons, acoustic phonons, ionized impurities, holes, and compositional disorder. Since not all of these interactions can be approximated by elastic scattering, the corresponding Boltzmann equation was solved by a variational principle. We also discuss directions for future work.
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Sandeep, Sathyan, Samuel Raetz, Jerome Wolfman, Beatrice Negulescu, Guozhen Liu, Jean-Louis Longuet, Théo Thréard, and Vitalyi E. Gusev. "Evaluation of Optical and Acoustical Properties of Ba1−xSrxTiO3 Thin Film Material Library via Conjugation of Picosecond Laser Ultrasonics with X-ray Diffraction, Energy Dispersive Spectroscopy, Electron Probe Micro Analysis, Scanning Electron and Atomic Force Microscopies." Nanomaterials 11, no. 11 (November 20, 2021): 3131. http://dx.doi.org/10.3390/nano11113131.
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Wide-range continuous spatial variation of the film composition in lateral compositionally graded epitaxial films requires the development of high throughput measurement techniques for their local and non-destructive characterization with the highest possible spatial resolution. Here we report on the first application of the picosecond laser ultrasonics (PLU) technique for the evaluation of acoustical and optical parameters of lateral compositionally graded film, the Ba1−xSrxTiO3 (0 ≤ x ≤ 1) material library. The film was not dedicatedly prepared for its opto-acousto-optic evaluation by PLU, exhibiting significant lateral variations in thickness and surface roughness. Therefore, the achieved measurements of the sound velocity and of the optical refractive index, and characterization of the surface roughness confirm the robustness of the PLU technique for thin film evaluation. We hope that the first measurements of the acoustical and optical properties of epitaxial grown Ba1−xSrxTiO3 (0 ≤ x ≤ 1) by PLU technique accomplished here provide the parameters required for more extended predictive design of the phononic, photonic and phoxonic mirrors and cavities with superior properties/functionalities for novel multifunctional nanodevices.
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"Many-body effects in layered systems." Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering Sciences 334, no. 1635 (March 15, 1991): 491–500. http://dx.doi.org/10.1098/rsta.1991.0029.
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An investigation of quasi-particle properties is presented in single- and double quantum-well systems as a function of electron density. Significant changes from bulk parameters are found with strong dependencies on the electron density and interwell separation. Low-energy plasmon modes are found to dominate the quasi- particle lifetime giving scattering rates up to an order of magnitude higher than optic phonons in these systems.
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Fortier, Aleksandra, Max Tsao, Nick D. Williard, Yinjiao Xing, and Michael G. Pecht. "Preliminary Study of Printing Optical-Based Materials using Aerosol Jet Deposition Process." International Journal of Current Engineering and Technology 8, no. 3 (May 20, 2018). http://dx.doi.org/10.14741/ijcet/v.8.3.16.
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This work examines the printing of optical-based materials using aerosol jet printing (AJP), an additive manufacturing process. Deposition of optical-based materials using the AJP process has potential to be applied in the fabrication of embedded fiber optic Bragg grating sensors. Made from silica (SiO2), fiber optic Bragg grating sensors are small, lightweight, and chemically inert, making them suitable for a variety of applications. This study examines the preparation and deposition of a newly developed silica-based printing ink. The results of the printing method, the impact of various printing and processing parameters on the deposition quality and microstructure, light reflectivity, scanning electron microscope (SEM) images, and content analyses of the deposited layers are presented. The results show uniform printed layers and demonstrate the capability of the AJP method as well as the newly developed silicabased ink to print high-quality commercial optical-based materials. The focus of this study is on the process/ optical material property interaction only; the printing of actual functional sensors on components and testing them will be discussed in later studies and is beyond the scope of this paper.
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Bisesto, Fabrizio, Mario Galletti, Maria Pia Anania, Gemma Costa, Massimo Ferrario, Riccardo Pompili, Arie Zigler, et al. "Simultaneous observation of ultrafast electron and proton beams in TNSA." High Power Laser Science and Engineering 8 (2020). http://dx.doi.org/10.1017/hpl.2020.19.
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The interaction of ultra-intense high-power lasers with solid-state targets has been largely studied for the past 20 years as a future compact proton and ion source. Indeed, the huge potential established on the target surface by the escaping electrons provides accelerating gradients of TV/m. This process, called target normal sheath acceleration, involves a large number of phenomena and is very difficult to study because of the picosecond scale dynamics. At the SPARC_LAB Test Facility, the high-power laser FLAME is employed in experiments with solid targets, aiming to study possible correlations between ballistic fast electrons and accelerated protons. In detail, we have installed in the interaction chamber two different diagnostics, each one devoted to characterizing one beam. The first relies on electro-optic sampling, and it has been adopted to completely characterize the ultrafast electron components. On the other hand, a time-of-flight detector, based on chemical-vapour-deposited diamond, has allowed us to retrieve the proton energy spectrum. In this work, we report preliminary studies about simultaneous temporal resolved measurements of both the first forerunner escaping electrons and the accelerated protons for different laser parameters.
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Werr, Ferdinand, Urs Eppelt, Ludger Müllers, and Dominique de Ligny. "Ultra-Short-Pulse Laser Filaments for Float Glass Cutting: Influence of Laser Parameters on Micro Cracks Formation." Frontiers in Physics 10 (March 24, 2022). http://dx.doi.org/10.3389/fphy.2022.862419.
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Utilizing ultra-short-pulse laser filamentation of glass is one of the latest developed techniques to cut glass. In comparison with other techniques the superior benefits are a small heat-affected zone, a quasi-non-gap cut, and the possibility to free from cut. However, despite the large interest in the laser/glass interaction for various laser sources and pulse durations, the process of cleaving and the underlying mechanisms are fairly undescribed. In this study, we utilized a Nd:YAG laser with an average power of 100 W, a center wavelength of 1,064 nm, and a pulse duration of 12 ps via a specially designed optic to generate laser filamentation in soda-lime- and borosilicate glass with varying Pitch and Burst parameters. The filaments and cut edge are analyzed with scanning electron- and laser scanning microscopy to study the topological phenomena and roughness. Photoelastic measurements were done to assess the stress distribution within the glass and show cumulative interactions at the filament extremity. From the observations made, phenomenological models are proposed to describe the initial micro crack formation considering the shock wave and thermal influence caused by the laser pulses. Two types of micro cracks are identified, with radial cracks passing through the filament and bypass cracks that form around the laser-affected zone. Models are elaborated for both glass types to evaluate the influence of a parameter change on the micro crack formation and the cleaving guidance. The different behavior between soda-lime- and borosilicate glass, with their distinct physical properties, helps to interpret the influence of laser parameters on the micro crack formation and the cleaving guidance.
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Karaagac, H., M. Parlak, and M. Saif Islam. "Synthesis of ZnO Nanowires by Hydrothermal Technique for Integration Into Chalcopyrite Thin Films." MRS Proceedings 1406 (2012). http://dx.doi.org/10.1557/opl.2012.26.
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ABSTRACTVertically oriented, highly dense ZnO nanowires (NWs) array was successfully grown on both glass and silicon substrates using hydrothermal technique. A systematic study was carried out to investigate the effects of growth parameters including growth time and thickness of ZnO seed layer on the quality of ZnO NWs in terms of their homogeneity and orientation in the vertical direction. The diameter as well as the length of grown ZnO NWs was found to be closely dependent on the thickness of the pre-coated ZnO seed layer. The structures of ZnO NWs and electron-beam evaporated AgGa0.5In0.5Se2 (AGIS) thin film have been characterized by X-ray diffraction measurements and optical properties were measured by transmission measurement. The optic band gap of AGIS thin film was found to be almost optimum (1.56 eV) to match the abundant part of solar cell spectrum. AGIS thin film was deposited on the synthesized ZnO NWs to form p-n heterojunction based inorganic solar cell, which exhibited photovoltaic behavior with a power conversion efficiency of 0.37 % under A.M (1.5) illumination.
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M, Jothi, and Sowmiya K. "Exploring the characteristics of the nickel oxide nanoparticles via Sol - gel method." Nanoscale Reports 3, no. 3 (September 9, 2020). http://dx.doi.org/10.26524/nr.3.24.
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Nickel Oxide (NiO) is an important transition metal oxide with cubic lattice structure. NiO is thermally stable that is suitable for tremendous applications in the field of optic, ceramic,glass, electro-chromic coatings, plastics, textiles, nanowires, nanofibers, electronics,energy technology, bio-medicine, magnetism and so on. In this present study, NiO nanoparticles were successfully synthesized by sol-gel technique. Nano-sols were prepared by dissolving Nickel-Chloride [NiCl2.6H2O] in NaOH solvent and were converted into nano structured gel on precipitation. A systematic change in preparation parameters like calcination temperature, time, pH value has been noticed in order to predict the influence on crystallite size. Then the prepared samples were characterized by the X-ray Diffraction Spectroscopic (XRD), UV-VIS Spectroscopy, Fourier Transform Infra-Red Spectroscopy (FTIR), Energy Dispersive X-ray Spectroscopy (EDX), Scanning Electron Microscopy (SEM) and Particle Size Analyzer (PSA). From XRD, the average crystalline-size has been calculated by Debye-Scherrer Equation and it was found to be 12.17 nm and the band gap energy of Nickel oxide (NiO) from UV studies reveals around 3.85 eV. Further, EDX and FTIR studies, confirm the presences of NiO nanoparticles. The SEM study exhibits the spherical like morphology of Nickel oxide (NiO). Further from PSA, the mean value of NiO nanoparticles has been determined.
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"Kinetic study on martensite formation in steels 1045 and 4340 under variable cooling rates." Revista ECIPeru, December 15, 2018, 68–76. http://dx.doi.org/10.33017/reveciperu2015.0011/.
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Kinetic study on martensite formation in steels 1045 and 4340 under variable cooling rates Dimitry V. Bubnoff1, Mariana M. O. Carvalho2, Thiago R.M. Lourenço1, Jose Adilson de Castro1 1 PPGEM, Industrial Engineering School/UFF, Volta Redonda/RJ, Brazil 2 Lappeenranta University of Technology/LUT, Skinnarilankatu, Lappeenranta Finland2 DOI: https://doi.org/10.33017/RevECIPeru2015.0011/ Abstract The experiments were carried with two steels with different chemical compositions, aiming at understanding and comparison with the available literature. The microstructures of steels 1045 and 4340 were characterized and quantified using scanning electron microscopy (SEM) and optic microscopy (OM) with quantitative methods. Based on the experimental results, the amount of martensite, the hardness and the microhardness were determined, as a function of the distance from the quenching end, under different cooling conditions. For predicting the evolution of martensitic fraction along the sample, Koistinen-Marburger’s (K-M) model was adopted. It was found that the parameters recommended in the literature for the traditional K-M model do not represent accurately the results obtained for the steel samples under investigation. According to indications found in recent literature, parameter corrections were proposed, leading to a modified K-M model which better represents the transformations observed in the different examined steels. Keywords: Kinetics, martensite, Koistinen-Marburger model.
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Cariati, Ida, Roberto Bonanni, Giuseppe Annino, Manuel Scimeca, Elena Bonanno, Giovanna D’Arcangelo, and Virginia Tancredi. "Dose–Response Effect of Vibratory Stimulus on Synaptic and Muscle Plasticity in a Middle-Aged Murine Model." Frontiers in Physiology 12 (June 11, 2021). http://dx.doi.org/10.3389/fphys.2021.678449.
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Whole body vibration plays a central role in many work categories and can represent a health risk to the musculoskeletal system and peripheral nervous system. However, studies in animal and human models have shown that vibratory training, experimentally and/or therapeutically induced, can exert beneficial effects on the whole body, as well as improve brain functioning and reduce cognitive decline related to the aging process. Since the effects of vibratory training depend on several factors, such as vibration frequency and vibration exposure time, in this work, we investigated whether the application of three different vibratory protocols could modulate synaptic and muscle plasticity in a middle-aged murine model, counteracting the onset of early symptoms linked to the aging process. To this end, we performed in vitro electrophysiological recordings of the field potential in the CA1 region of mouse hippocampal slices, as well as histomorphometric and ultrastructural analysis of muscle tissue by optic and transmission electron microscopy, respectively. Our results showed that protocols characterized by a low vibration frequency and/or a longer recovery time exert positive effects at both hippocampal and muscular level, and that these effects improve significantly by varying both parameters, with an action comparable with a dose–response effect. Thus, we suggested that vibratory training may be an effective strategy to counteract cognitive impairment, which is already present in the early stages of the aging process, and the onset of sarcopenia, which is closely related to a sedentary lifestyle. Future studies are needed to understand the underlying molecular mechanisms and to determine an optimal vibratory training protocol.
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Clerot, Lídia Luzia, Paula Stieven Hünning, Marcelle Bettio, Marcela Torikachvili, Michelle Beck Petersen, Alessandra Fernandez Silva, Andre Silva Carissimi, and João Antonio Tadeu Pigatto. "Morphology of Endothelial Cells from Different Regions of the Swine Cornea." Acta Scientiae Veterinariae 47, no. 1 (January 10, 2019). http://dx.doi.org/10.22456/1679-9216.89436.
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Background: The corneal endothelium is a monolayer of polygonal cells which constitute the last layer of the cornea. The integrity of this layer is critical to cornea transparency. The characterization of normal corneal endothelial morphology is important not only to clinical evaluation but also to selection of areas of the cornea with better quality to be employed as donor tissue. The aim of the present study was to evaluate the morphology of endothelial cells from different regions of the swine cornea after alizarin red staining using optical microscopy.Materials, Methods & Results: Twenty-four healthy eyes from 12 swine Large White breed, with 14-month-old, males or females obtained from a licensed Brazilian commercial slaughterhouse were studied. Immediately after humane slaughter, the eyes were enucleated and submitted to ophthalmic examination. Eyes with signs of diseases of the anterior segment were excluded. The cornea, with 3 mm of the sclera, was removed and placed on a glass microscope slide with the endothelial side up. Four radial incisions were made in the periphery of the cornea to better accommodate the cornea on the microscope slide. Alizarin red was diluted in isotonic solution (0.2 g/100 mL) and the pH was adjusted to 4.2 with hydrochloric acid. Three drops of alizarin red were placed on the corneal endothelium. After 90 s, the dye was removed from the cornea with balanced saline solution. The corneal endothelium was examined and photographed using an optical microscope. All evaluations were performed by the same investigator. Photomicrographs were taken of central, superior, inferior, nasal and temporal corneal areas. Parameter studied included endothelial cell morphology. For the statistical analysis, was employed the ANOVA variance test (repeated measures). Differences were considered statistically significant at P < 0.05. Normal endothelium cells were mainly hexagonal (83.7%), pentagonal (7.45%) and heptagonal (8.8%), with a minimal number of cells of other shapes present. There were no significant statistical differences in the proportion of the morphology and the different regions of the cornea (P = 0.31).Discussion: Different techniques are available for the analysis of corneal endothelium, including mainly scanning electron microscopy, specular microscopy and optical microscopy. The analysis of the morphology of corneal endothelium with an optic microscope after staining with alizarin red has been described as an effective, rapid and cost-efficient method, since this dye blends the borated cells, allowing identification. In the present study, using optical microscopy and coloration with alizarin red it was possible to explore and to obtain images of the swine endothelium of all regions of the cornea. The analysis of the cellular morphology or the percentage of hexagonal cells are among the main parameters used to evaluate the health of the corneal endothelium. In this study, the endothelium had the predominance of the hexagonal shape in all regions studied. In swine, there are no studies evaluating the shape of the endothelial cells in the five different regions of the cornea. This study has demonstrated that the parameters evaluated in swine did not differ significantly between the various places of the cornea.