scholarly journals Relation of Jupiter’s dawnside main emission intensity to magnetospheric currents during the Juno mission

2022 ◽  
Author(s):  
J. D. Nichols ◽  
S. W. H. Cowley
Keyword(s):  
Emission Intensity ◽  
Magnetospheric Currents ◽  
Juno Mission

Characterization of Amethysts from Sukamara, Central Kalimantan, Using Laser-Induced Breakdown Spectroscopy (LIBS)

2020 ◽  
Vol 1 (2) ◽  
pp. 5-8
Author(s):  
Komang Gde Suastika, Heri Suyanto, Gunarjo, Sadiana, Darmaji
Keyword(s):  
Emission Intensity ◽  
Laser Energy ◽  
Emission Spectra ◽  
Atomic Emission ◽  
Laser Induced Breakdown Spectroscopy ◽  
Chemical Formula ◽  
Central Kalimantan ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown

Abstract - Laser-Induced Breakdown Spectroscopy (LIBS) is one method of atomic emission spectroscopy using laser ablation as an energy source. This method is used to characterize the type of amethysts that originally come from Sukamara, Central Kalimantan. The result of amethyst characterization can be used as a reference for claiming the natural wealth of the amethyst. The amethyst samples are directly taken from the amethyst mining field in the District Gem Amethyst and consist of four color variations: white, black, yellow, and purple. These samples were analyzed by LIBS, using laser energy of 120 mJ, delay time detection of 2 μs and accumulation of 3, with and without cleaning. The purpose of this study is to determine emission spectra characteristics, contained elements, and physical characteristics of each amethyst sample. The spectra show that the amethyst samples contain some elements such as Al, Ca, K, Fe, Gd, Ba, Si, Be, H, O, N, Cl and Pu with various emission intensities. The value of emission intensity corresponds to concentration of element in the sample. Hence, the characteristics of the amethysts are based on their concentration value. The element with the highest concentration in all samples is Si, which is related to the chemical formula of SiO2. The element with the lowest concentration in all samples is Ca that is found in black and yellow amethysts. The emission intensity of Fe element can distinguish between white, purple, and yellow amethyst. If Fe emission intensity is very low, it indicates yellow sample. Thus, we may conclude that LIBS is a method that can be used to characterize the amethyst samples.Key words: amethyst, impurity, laser-induced, breakdown spectroscopy, characteristic, gemstones

scholarly journals Study of the effect of band gap and photoluminescence on biological properties of polyaniline/CdS QD nanocomposites based on natural polymer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Azita Alipour ◽  
Moslem Mansour Lakouraj ◽  
Hamed Tashakkorian
Keyword(s):  
Band Gap ◽  
Emission Intensity ◽  
Energy Gap ◽  
Conductive Polymer ◽  
Biological Properties ◽  
Synergy Effect ◽  
Natural Polymer ◽  
Toxicity Effect ◽  
Heterogeneous Chemical ◽  
Cell Tissue

AbstractIn this work, band gap, photoluminescence and biological properties of new bionanocomposites based on polyaniline (PANi)/hydrolyzed pectin (HPEc)/cadmium sulfide (CdS) QD nanoparticles (NPs) were studied. In order to improve the morphology and properties, CdS NPs were modified with epichlorohydrin to obtain the modified CdS (mCdS). The CdS@HPEc-g-PANi and mCdS@HPEc-g-PANi samples were synthesized via heterogeneous chemical polymerization and characterized by FTIR, 1HNMR, SEM/XRD, EDX/TEM/EDX-mapping and TGA analyses. The objective of this work is the study of physical, optical and cytotoxicity properties of the nanocomposites and comparison between them. The SEM, XRD and TGA images showed that the modification of NPs resulted in homogeneous morphology, increase of crystalline structure and high thermal stability which influenced on physical and biological property. According to UV-DRS analysis, the mCdS@HPEc-g-PANi indicated lower energy gap compared to the CdS@HPEc-g-PANi nancomposite. The presence of conductive polymer and synergy effect between the PANi and CdS caused higher PL intensity in the CdS@HPEc-g-PANi nanocomposite compared to pure CdS. The emission intensity in the mCdS@HPEc-g-PANi nanocomposite was reduced since the organic modifying agent cause reducing emission intensity. The mCdS@HPEc-g-PANi nanocomposite, due to more compatibility of organic agent with cellular walls of biological cells that help to the diffusion of metal CdS NPs into cell tissue indicated more toxicity effect on cell growth.

scholarly journals Influence of Calcination Temperature on Crystal Growth and Optical Characteristics of Eu3+ Doped ZnO/Zn2SiO4 Composites Fabricated via Simple Thermal Treatment Method

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 115
Author(s):  
Suhail Huzaifa Jaafar ◽  
Mohd Hafiz Mohd Zaid ◽  
Khamirul Amin Matori ◽  
Sidek Hj. Ab Aziz ◽  
Halimah Mohamed Kamari ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Band Gap ◽  
Calcination Temperature ◽  
Emission Intensity ◽  
Emission Spectra ◽  
Treatment Method ◽  
Absorption Bands ◽  
Vis Spectroscopy ◽  
Doped Zno ◽  
Zno Crystal

This research paper proposes the usage of a simple thermal treatment method to synthesis the pure and Eu3+ doped ZnO/Zn2SiO4 based composites which undergo calcination process at different temperatures. The effect of calcination temperatures on the structural, morphological, and optical properties of ZnO/Zn2SiO4 based composites have been studied. The XRD analysis shows the existence of two major phases which are ZnO and Zn2SiO4 crystals and supported by the finding in the FT-IR. The FESEM micrograph further confirms the existence of both ZnO and Zn2SiO4 crystal phases, with progress in the calcination temperature around 700–800 °C which affects the existence of the necking-like shape particle. Absorption humps discovered through UV-Vis spectroscopy revealed that at the higher calcination temperature effects for higher absorption intensity while absorption bands can be seen at below 400 nm with dropping of absorption bands at 370–375 nm. Two types of band gap can be seen from the energy band gap analysis which occurs from ZnO crystal and Zn2SiO4 crystal progress. It is also discovered that for Eu3+ doped ZnO/Zn2SiO4 composites, the Zn2SiO4 crystal (5.11–4.71 eV) has a higher band gap compared to the ZnO crystal (3.271–4.07 eV). While, for the photoluminescence study, excited at 400 nm, the emission spectra of Eu3+ doped ZnO/Zn2SiO4 revealed higher emission intensity compared to pure ZnO/Zn2SiO4 with higher calcination temperature exhibit higher emission intensity at 615 nm with 700 °C being the optimum temperature. The emission spectra also show that the calcination temperature contributed to enhancing the emission intensity.

scholarly journals Down-Shifting in the YAM: Ce3+ + Yb3+ System for Solar Cells

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2753
Author(s):  
Bartosz Fetliński ◽  
Sebastian Turczyński ◽  
Michał Malinowski ◽  
Paweł Szczepański
Keyword(s):  
Energy Transfer ◽  
Emission Intensity ◽  
Potential Application ◽  
Single Photon ◽  
Solar Spectrum ◽  
Excitation Power ◽  
Photovoltaic Devices ◽  
Photoluminescence Properties ◽  
System A ◽  
Down Conversion

In this work, we investigate Ce3+ to Yb3+ energy transfer in Y4Al2O9 (YAM) for potential application in solar spectrum down-converting layers for photovoltaic devices. Photoluminescence properties set, of 10 samples, of the YAM host activated with Ce3+ and Yb3+ with varying concentrations are presented, and the Ce3+ to Yb3+ energy transfer is proven. Measurement of highly non-exponential luminescence decays of Ce3+ 5d band allowed for the calculation of maximal theoretical quantum efficiency, of the expected down-conversion process, equal to 123%. Measurements of Yb3+ emission intensity, in the function of excitation power, confirmed the predominantly single-photon downshifting character of Ce3+ to Yb3+ energy transfer. Favorable location of the Ce3+ 5d bands in YAM makes this system a great candidate for down-converting, and down-shifting, luminescent layers for photovoltaics.

scholarly journals A physico-chemical model to study the ion density distribution in the inner coma of comet C/2016 R2 (Pan-STARRS)

2020 ◽  
Author(s):  
Susarla Raghuram ◽  
Anil Bhardwaj ◽  
Damien Hutsemékers ◽  
Cyrielle Opitom ◽  
Jean Manfroid ◽  
...  
Keyword(s):  
Density Distribution ◽  
Electron Impact ◽  
Emission Intensity ◽  
Impact Ionization ◽  
Excitation Source ◽  
Resonance Fluorescence ◽  
Ion Density ◽  
Physico Chemical ◽  
Intensity Ratios ◽  
Ion Emission

Abstract The recent observations show that comet C/2016 R2 (Pan-Starrs) has a unique and peculiar composition when compared with several other comets observed at 2.8 au heliocentric distance. Assuming solar resonance fluorescence is the only excitation source, the observed ionic emission intensity ratios are used to constrain the corresponding neutral abundances in this comet. We developed a physico-chemical model to study the ion density distribution in the inner coma of this comet by accounting for photon and electron impact ionization of neutrals, charge exchange and proton transfer reactions between ions and neutrals, and electron-ion thermal recombination reactions. Our calculations show that CO$_2^+$ and CO+ are the major ions in the inner coma, and close to the surface of nucleus CH3OH+, CH3OH$_2^+$ and O$_2^+$ are also important ions. By considering various excitation sources, we also studied the emission mechanisms of different excited states of CO+, CO$_2^+$, N$_2^+$, and H2O+. We found that the photon and electron impact ionization and excitation of corresponding neutrals significantly contribute to the observed ionic emissions for radial distances smaller than 300 km and at larger distances, solar resonance fluorescence is the major excitation source. Our modelled ion emission intensity ratios are consistent with the ground-based observations. Based on the modelled emission processes, we suggest that the observed ion emission intensity ratios can be used to derive the neutral composition in the cometary coma only when the ion densities are significantly controlled by photon and photoelectron impact ionization of neutrals rather than by the ion-neutral chemistry.

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