An antifouling impedimetric sensor based on zinc oxide embedded polyvinyl alcohol nanoplatelets for wide range dopamine determination in the presence of high concentration ascorbic acid

2021 ◽  
pp. 114278
Author(s):  
Motahhare Emadoddin ◽  
Sayed Ahmad Mozaffari ◽  
Fateme Ebrahimi
Keyword(s):  
Ascorbic Acid ◽  
Zinc Oxide ◽  
Polyvinyl Alcohol ◽  
High Concentration ◽  
Wide Range ◽  
Dopamine Determination

Wide range modulation of synaptic weight in thin-film transistors with hafnium oxide gate insulator and indium-zinc oxide channel layer for artificial synapse application

Nanoscale ◽  
2021 ◽  
Author(s):  
Keonwon Beom ◽  
Jimin Han ◽  
Hyun-Mi Kim ◽  
Tae-Sik Yoon
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Thin Film Transistors ◽  
Hafnium Oxide ◽  
Synaptic Weight ◽  
Drain Current ◽  
Gate Insulator ◽  
Channel Layer ◽  
Indium Zinc Oxide ◽  
Wide Range

Wide range synaptic weight modulation with a tunable drain current was demonstrated in thin-film transistors (TFTs) with a hafnium oxide (HfO2−x) gate insulator and an indium-zinc oxide (IZO) channel layer...

Engineering the shape of Zinc Oxide crystals via sonochemical or hydrothermal solution-based methods

2008 ◽  
Vol 1087 ◽  
Author(s):  
Marco Palumbo ◽  
Simon J. Henley ◽  
Thierry Lutz ◽  
Vlad Stolojan ◽  
David Cox ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Self Assembly ◽  
Hydrothermal Solution ◽  
Good Control ◽  
Transparent Conductors ◽  
Zno Nanostructures ◽  
Large Area ◽  
Light Emitting Devices ◽  
Wide Range ◽  
Solution Methods

AbstractRecent results in the use of Zinc Oxide (ZnO) nano/submicron crystals in fields as diverse as sensors, UV lasers, solar cells, piezoelectric nanogenerators and light emitting devices have reinvigorated the interest of the scientific community in this material. To fully exploit the wide range of properties offered by ZnO, a good understanding of the crystal growth mechanism and related defects chemistry is necessary. However, a full picture of the interrelation between defects, processing and properties has not yet been completed, especially for the ZnO nanostructures that are now being synthesized. Furthermore, achieving good control in the shape of the crystal is also a very desirable feature based on the strong correlation there is between shape and properties in nanoscale materials. In this paper, the synthesis of ZnO nanostructures via two alternative aqueous solution methods - sonochemical and hydrothermal - will be presented, together with the influence that the addition of citric anions or variations in the concentration of the initial reactants have on the ZnO crystals shape. Foreseen applications might be in the field of sensors, transparent conductors and large area electronics possibly via ink-jet printing techniques or self-assembly methods.

Mechanical and Barrier Properties of Polyvinyl Alcohol Films Modified with Carbon Nanotubes and Zinc Oxide

2021 ◽  
Vol 877 ◽  
pp. 27-33
Author(s):  
Ya Li Sun ◽  
Yi Hua Wen ◽  
Qing Cai Liu ◽  
Jui Chin Chen ◽  
Manual Reyes de Guzman ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Polyvinyl Alcohol ◽  
Nanocomposite Film ◽  
Testing Machine ◽  
Barrier Properties ◽  
X Ray Diffraction ◽  
Tensile Testing Machine ◽  
Solution Blending ◽  
Vapor Permeation ◽  
Property Measurement

A solution blending technique was employed to form a nanocomposite film of polyvinyl alcohol modified with carbon nanotube and zinc oxide (CNT/ZnO). The film was characterized using a tensile testing machine, X-ray diffraction, scanning electron microscopy, a contact angle device, and barrier property measurement. When the CNT/ZnO content was 1.2 phr, the results from mechanical property and water vapor permeation tests showed that the nanocomposite film had good tensile strength and water resistance. Moreover, CNT/ZnO improved the hydrophobicity of the film. CNT/ZnO/can improve the performance of PVA and is a good nanofiller of PVA. The results of this research might have the opportunity to be used as packaging film materials in the future.

Effects of sulfate concentration and sludge retention time on the interaction between methane production and sulfate reduction for butyrate

1994 ◽  
Vol 30 (8) ◽  
pp. 45-54 ◽  
Author(s):  
O. Mizuno ◽  
Y. Y. Li ◽  
T. Noike
Keyword(s):  
Sulfate Reduction ◽  
Retention Time ◽  
Methane Production ◽  
Electron Flow ◽  
Degradation Pathway ◽  
Sulfate Concentration ◽  
High Concentration ◽  
Total Electron ◽  
Sludge Retention Time ◽  
Wide Range

The effects of sulfate concentration and COD/S ratio on the anaerobic degradation of butyrate were investigated by using 2.0 L anaerobic chemostat-type reactor at 35°C. The study was conducted over a wide range of the COD/S ratio (1.5 to 148) by varying COD concentrations (2500–10000 mg/L) and sulfate concentrations (68–1667 mg-S/L) in the substrate. The sludge retention time at each COD/S ratio was changed from 5 to 20 days. The interaction between methane producing bacteria (MPB) and sulfate-reducing bacteria (SRB) was evidently influenced by COD/S ratio in the substrate. When COD/S ratio was 6.0 or more, methane production was the predominate reaction and over 80% of the total electron flow was used by MPB. At the COD/S ratio of 1.5, SRB utilzed over 50% of the total electron flow. A large amount of sulfate reduction resulted in not only the decrease of methane production, but also the rapid increase of the bacterial growth. The degradation pathway of butyrate and the composition of bacterial populations in the reactor were also dominated by COD/S ratio. In sulfate depleted condition, butyrate was degraded to methane via acetate and hydrogen by MPB. On the other hand, butyrate was firstly degraded into sulfide and acetate in sulfate rich conditions by SRB, and the produced acetate was then degraded by acetate consuming MPB and SRB. The methanogenesis from acetate was inhibited by the high concentration of sulfide.

scholarly journals Application of Electron Backscatter Diffraction (EBSD) for Crystallographic Characterization of Aluminum-Doped Zinc Oxide Sputtered Films

2013 ◽  
Vol 19 (S4) ◽  
pp. 103-104
Author(s):  
C.B. Garcia ◽  
E. Ariza ◽  
C.J. Tavares
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Zinc Oxide ◽  
Electron Backscatter Diffraction ◽  
Wide Range ◽  
Electron Backscatter ◽  
Aluminum Doped Zinc Oxide ◽  
Ebsd Technique ◽  
Backscatter Diffraction

Zinc Oxide is a wide band-gap compound semiconductor that has been used in optoelectronic and photovoltaic applications due to its good electrical and optical properties. Aluminium has been an efficient n-type dopant for ZnO to produce low resistivity films and high transparency to visible light. In addition, the improvement of these properties also depends on the morphology, crystalline structure and deposition parameters. In this work, ZnO:Al films were produced by d.c. pulsed magnetron sputtering deposition from a ZnO ceramic target (2.0 wt% Al2O3) on glass substrates, at a temperature of 250 ºC.The crystallographic orientation of aluminum doped zinc oxide (ZnO:Al) thin films has been studied by Electron Backscatter Diffraction (EBSD) technique. EBSD coupled with Scanning Electron Microscopy (SEM) is a powerful tool for the microstructural and crystallographic characterization of a wide range of materials.The investigation by EBSD technique of such films presents some challenges since this analysis requires a flat and smooth surface. This is a necessary condition to avoid any shadow effects during the experiments performed with high tilting conditions (70º). This is also essential to ensure a good control of the three dimensional projection of the crystalline axes on the geometrical references related to the sample.Crystalline texture is described by the inverse pole figure (IPF) maps (Figure 1). Through EBSD analysis it was observed that the external surface of the film presents a strong texture on the basal plane orientation (grains highlighted in red colour). Furthermore it was possible to verify that the grain size strongly depends on the deposition time (Figure 1 (a) and (b)). The electrical and optical film properties improve with increasing of the grain size, which can be mainly, attributed to the decrease in scattering grain boundaries which leads to an increasing in carrier mobility (Figure 2).The authors kindly acknowledge the financial support from the Portuguese Foundation for Science and Technology (FCT) scientific program for the National Network of Electron Microscopy (RNME) EDE/1511/RME/2005.

Design and optimization of process parameters of polyvinyl (alcohol)/chitosan/nano zinc oxide hydrogels as wound healing materials

2019 ◽  
Vol 207 ◽  
pp. 542-554 ◽  
Author(s):  
Mohammad Taghi Khorasani ◽  
Alireza Joorabloo ◽  
Hassan Adeli ◽  
Zohreh Mansoori-Moghadam ◽  
Armaghan Moghaddam
Keyword(s):  
Wound Healing ◽  
Zinc Oxide ◽  
Polyvinyl Alcohol ◽  
Process Parameters ◽  
Design And Optimization ◽  
Optimization Of Process Parameters ◽  
Nano Zinc Oxide ◽  
Nano Zinc

scholarly journals Phytochemical screening and HPLC- UV method quantiϐication of Flavonoids in Coffee Arabica green seeds

2020 ◽  
Vol 11 (SPL4) ◽  
pp. 1895-1904
Author(s):  
Bothiraj K V ◽  
Kalaivani P ◽  
Murugan K ◽  
Vanitha V
Keyword(s):  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Biologically Active ◽  
Coffee Bean ◽  
Green Coffee ◽  
High Concentration ◽  
Antimitotic Activity ◽  
Wide Range ◽  
Anti Inflammatory ◽  
Green Coffee Bean

The green coffee bean is the most commonly used beverages in India and it is one of the most commercialised food products. They have a rich source of biologically active compounds that are important for human health. The coffee tree or a shrub belongs to the family Rubiaceae. Commercially available, two species of green coffee bean are Coffea Arabica and Coffea canephora. Cancer is the most important cause of death. Apart from cancer, quercetin can also prevent Osteoporosis. The phytochemicals present in the green coffee bean can be used as an alternate therapy for cancer due to its antimitotic activity and free radical scavenging activity. Total antioxidant shows IC50 value 45.81. Kaempferol is a potent antioxidant that can defence against free radicals and cure chronic diseases. Flavonoids are phenolic substances that act as an antioxidant, anti-inflammatory, anti-allergenic, antiviral and also have vasodilating actions. Green coffee bean shows a high concentration of Flavonoids in hydroethanolic extraction. The aim of this study is used to analyse the presence of Flavonoids in green coffee bean by using High-performance Liquid Chromatography (HPLC). Flavonoids are potent antioxidant that can bind to a protein. Flavonoids show a wide range of biological and pharmacological activities like anti-allergic, anti-inflammatory, anti-cancer and anti-microbial activity.

scholarly journals Characterization and thermoluminescence study of gamma irradiated Tb-doped ZnO and undoped ZnO synthesized by spray pyrolysis method

Nova Scientia ◽  
2021 ◽  
Vol 13 (27) ◽  
Author(s):  
Alejandro Ortiz-Morales ◽  
Manuel García-Hipólito ◽  
Epifanio Cruz-Zaragoza ◽  
Ramón Gómez-Aguilar
Keyword(s):  
Zinc Oxide ◽  
Gamma Radiation ◽  
Spray Pyrolysis ◽  
Oxide Films ◽  
Spray Pyrolysis Method ◽  
Order Kinetic ◽  
Zinc Oxide Films ◽  
Pyrolysis Method ◽  
Wide Range ◽  
Doped Zno

High gamma dose-resistant undoped ZnO and Tb-doped ZnO thermoluminescent (TL) micro-phosphors were prepared by the spray pyrolysis method. Scanning electron microscopy shows crystalline rods with hexagonal morphology, (0.1-0.4 µm diameter, and about 1 µm length). Raman spectra dispersion reveals a würtzite form. Photoluminescence (PL) study of irradiated zinc oxide films indicates the generation of defects produced by gamma irradiation resulting in an increased probability of electron-hole exciton recombination. PL spectrum shows emission bands from 5D4-7Fj=6,5,4,3 transitions ascribed to Tb3+ dopant in zinc oxide phosphor. X-ray diffraction patterns for both types of films growth (undoped ZnO and Tb-doped ZnO) are typical of zinc oxide crystalline structure, with no noticeable effect of Tb ions. Dosimetric properties, for both samples, show a low TL fading signal and TL reproducibility signal for undoped ZnO and Tb-doped ZnO samples was 29 and 57 %, respectively. The kinetic parameters such as activation energy E, frequency factor s, and Rm values, were obtained by Computerized Glow Curve Deconvolution (CGCD) assuming Mixed Order Kinetic model (MOK). The results show that the MOK well described the glow curves of zinc oxide films. The heating rate effects produced a broadening of glow peak located at 420 K. For purposes like radiation detector, atomic effective number (Zeff) was obtained: 27.74 and 56.47 for undoped ZnO and Tb-doped ZnO samples, respectively. The samples were exposed to gamma radiation in a wide range of 0.25–20 kGy dose. TL properties of undoped ZnO and Tb-doped ZnO samples show that these materials could be used to detect high doses in a gamma radiation field.

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