scholarly journals Organometallic Approach for the Preparation of Zinc Oxide Nanostructured Gas Sensitive Layers

2015 ◽  
Vol 644 ◽  
pp. 22-25
Author(s):  
Justyna Jońca ◽  
L. Myrtil Kahn ◽  
Katia Fajerwerg ◽  
Bruno Chaudret ◽  
Audrey Chapelle ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Gas Sensors ◽  
Sensor Response ◽  
Zno Nanostructures ◽  
Response Level ◽  
Organometallic Precursor ◽  
Ink Jet ◽  
Reducing Gases ◽  
Hydrolysis Of ◽  
Controlled Hydrolysis

A reproducible organometallic approach was used in order to prepare zinc oxide gas sensitive layers. Various ZnO nanostructures with well-defined morphology were prepared by controlled hydrolysis of suitable organometallic precursor. These nanomaterials were deposited on miniaturized gas sensors substrates by an ink-jet method. The as prepared devices were tested towards different reducing gases, namely: CO, C3H8, and NH3. We showed that the morphology of these nanostructures significantly influences the sensor response level and selectivity to the reducing gases.

scholarly journals Thin Film Gas Sensors Based on Planetary Ball-Milled Zinc Oxide Nanoinks: Effect of Milling Parameters on Sensing Performance

2021 ◽  
Vol 11 (20) ◽  
pp. 9676
Author(s):  
Raju Sapkota ◽  
Pengjun Duan ◽  
Tanay Kumar ◽  
Anusha Venkataraman ◽  
Chris Papadopoulos
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Gas Sensors ◽  
Zno Nanoparticles ◽  
Food Packaging ◽  
Room Temperature ◽  
Industrial Applications ◽  
Sensor Response ◽  
Particle Sizes ◽  
Zno Nanoparticle

Planetary ball-milled zinc oxide (ZnO) nanoparticle suspensions (nanoinks) were used to produce thin film chemiresistive gas sensors that operate at room temperature. By varying milling or grinding parameters (speed, time, and solvent) different thin film gas sensors with tunable particle sizes and porosity were fabricated and tested with dry air/oxygen against hydrogen, argon, and methane target species, in addition to relative humidity, under ambient light conditions. Grinding speeds of up to 1000 rpm produced particle sizes and RMS thin film roughness below 100 nm, as measured by atomic force and scanning electron microscopy. Raman spectroscopy, photoluminescence, and X-ray analysis confirmed the purity and structure of the resulting ZnO nanoparticles. Gas sensor response at room temperature was found to peak for nanoinks milled at 400 rpm and for 30 min in ethylene glycol and deionized water, which could be correlated to an increased film porosity and enhanced variation in electron concentration resulting from adsorption/desorption of oxygen ions on the surfaces of ZnO nanoparticles. Sensor response and dynamic behavior was found to improve as the temperature was increased, peaking between 100 and 150 °C. This work demonstrates the use of low-cost PBM nanoinks as the active materials for solution-processed thin film gas/humidity sensors for use in environmental, medical, food packaging, laboratory, and industrial applications.

scholarly journals Characterization of Glycoside Hydrolase Family 5 Proteins in Schizosaccharomyces pombe

2010 ◽  
Vol 9 (11) ◽  
pp. 1650-1660 ◽  
Author(s):  
Encarnación Dueñas-Santero ◽  
Ana Belén Martín-Cuadrado ◽  
Thierry Fontaine ◽  
Jean-Paul Latgé ◽  
Francisco del Rey ◽  
...  
Keyword(s):  
Cell Wall ◽  
Schizosaccharomyces Pombe ◽  
Protein Characterization ◽  
Wall Material ◽  
Glycoside Hydrolase Family ◽  
Content Type ◽  
Hydrolysis Of ◽  
Controlled Hydrolysis ◽  
Hydrolase Family

ABSTRACT In yeast, enzymes with β-glucanase activity are thought to be necessary in morphogenetic events that require controlled hydrolysis of the cell wall. Comparison of the sequence of the Saccharomyces cerevisiae exo-β(1,3)-glucanase Exg1 with the Schizosaccharomyces pombe genome allowed the identification of three genes that were named exg1 + (locus SPBC1105.05), exg2 + (SPAC12B10.11), and exg3 + (SPBC2D10.05). The three proteins have different localizations: Exg1 is secreted to the periplasmic space, Exg2 is a membrane protein, and Exg3 is a cytoplasmic protein. Characterization of the biochemical activity of the proteins indicated that Exg1 and Exg3 are active only against β(1,6)-glucans while no activity was detected for Exg2. Interestingly, Exg1 cleaves the glucans with an endohydrolytic mode of action. exg1 + showed periodic expression during the cell cycle, with a maximum coinciding with the septation process, and its expression was dependent on the transcription factor Sep1. The Exg1 protein localizes to the septum region in a pattern that was different from that of the endo-β(1,3)-glucanase Eng1. Overexpression of Exg2 resulted in an increase in cell wall material at the poles and in the septum, but the putative catalytic activity of the protein was not required for this effect.

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.

scholarly journals Short-Time Fourier Transform and Decision Tree-Based Pattern Recognition for Gas Identification Using Temperature Modulated Microhotplate Gas Sensors

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Aixiang He ◽  
Jun Yu ◽  
Guangfen Wei ◽  
Yi Chen ◽  
Hao Wu ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Fourier Transform ◽  
Decision Tree ◽  
Gas Sensors ◽  
Operating Temperature ◽  
Ambient Air ◽  
Sensor Response ◽  
Short Time Fourier Transform ◽  
Short Time ◽  
Different Gases

Because the sensor response is dependent on its operating temperature, modulated temperature operation is usually applied in gas sensors for the identification of different gases. In this paper, the modulated operating temperature of microhotplate gas sensors combined with a feature extraction method based on Short-Time Fourier Transform (STFT) is introduced. Because the gas concentration in the ambient air usually has high fluctuation, STFT is applied to extract transient features from time-frequency domain, and the relationship between the STFT spectrum and sensor response is further explored. Because of the low thermal time constant, the sufficient discriminatory information of different gases is preserved in the envelope of the response curve. Feature information tends to be contained in the lower frequencies, but not at higher frequencies. Therefore, features are extracted from the STFT amplitude values at the frequencies ranging from 0 Hz to the fundamental frequency to accomplish the identification task. These lower frequency features are extracted and further processed by decision tree-based pattern recognition. The proposed method shows high classification capability by the analysis of different concentration of carbon monoxide, methane, and ethanol.

Hydrolysis of Zinc Ion and Solubility of Zinc Oxide in High-Temperature Aqueous Systems

1997 ◽  
Vol 127 (3) ◽  
pp. 292-299 ◽  
Author(s):  
Yukiko Hanzawa ◽  
Daisuke Hiroishi ◽  
Chihiro Matsuura ◽  
Kenkichi Ishigure ◽  
Masashi Nagao ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
High Temperature ◽  
Zinc Ion ◽  
Aqueous Systems ◽  
Hydrolysis Of

Green synthesis and antimicrobial activity of ZnO nanostructures Punica granatum shell extract

2017 ◽  
Vol 6 (3) ◽  
Author(s):  
Ercan Karaköse ◽  
Hakan Çolak ◽  
Fatih Duman
Keyword(s):  
Antimicrobial Activity ◽  
Zinc Oxide ◽  
Green Synthesis ◽  
Aqueous Extract ◽  
New Technologies ◽  
Punica Granatum ◽  
Zno Nanostructures ◽  
Zno Nps ◽  
Potential Applications ◽  
Environmentally Safe

AbstractThe manufacture of nanoparticles (NPs) is a new area of investigation due to potential applications related to the improvement of new technologies; in particular, environmentally safe manufactured nanomaterials have become a growing area within nanoscience. In this research, we synthesized zinc oxide (ZnO)-NPs using an aqueous extract of

scholarly journals Production of Xylo-oligosaccharides (XOS) by controlled hydrolysis of Xylan using immobilized Xylanase from Aspergillus niger with improved properties

2018 ◽  
Vol 5 (4) ◽  
Author(s):  
Caio C. Aragon ◽  
Ana I. Ruiz-Matute ◽  
Nieves Corzo ◽  
Rubens Monti ◽  
Jose M. Guisán ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Hydrolysis Of ◽  
Controlled Hydrolysis

scholarly journals Characterization of Zinc oxide Nanostructures prepared by hydrothermal method with Antibacterial property

2019 ◽  
Vol 17 (42) ◽  
pp. 108-124
Author(s):  
Ibrahim Abdulkareem Ali
Keyword(s):  
Zinc Oxide ◽  
Antibacterial Activity ◽  
Crystallite Size ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Antibacterial Property ◽  
Zno Nanostructures ◽  
Zinc Oxide Nanostructures ◽  
Oxide Nanostructures ◽  
Uv Visible

        In this study, Zinc oxide nanostructures were synthesized via a hydrothermal method by using zinc nitrate hexahydrate and sodium hydroxide as a precursor. Three different annealing temperatures were used to study their effect on ZnO NSs properties. The synthesized nanostructure was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Atomic force microscope (AFM), and Fourier Transform Infrared Spectroscopy (FTIR). Their optical properties were studied by using UV -visible spectroscopy. The XRD analysis confirms that all ZnO nanostructures have the hexagonal wurtzite structure with average crystallite size within the range of (30.59 - 34.52) nm. The crystallite size increased due to the incensement of annealing temperature. FESEM analysis indicates that ZnO has hexagonal shape of cylindrical pores, plate-like nanocrystals and Nanorods. AFM analysis shows that the average surface roughness of ZnO Nanostructures increases from 3.96 to 19.1 nm with the increase of annealing temperature. The FTIR peaks indicate successful preparation of ZnO Nanostructures. The FTIR method was used to analyses the chemical bonds which conformed the present of the Zn-O group in the region between (400-500) cm-1. The UV-visible showed a red shift in the absorption spectra related to the shift in the energy gap related to increase in the particle size.  the band gap energy has been calculated from the optical absorption spectra. The annealing process has been fond more effective on the value of energy gap. As the annealing temperature increases, the value of energy gap, increases as well; from (3.12to 3.22) eV. The prepared Nanostructure is used for antibacterial property. It shows strong antibacterial activity against S. aureus and P.aeuruginosa bacteria by the agar disc diffusion method. The white precipitate of ZnO NSs has superior antibacterial activity on gram-positive (S. aureus) than the gram-negative (P.aeuruginosa) bacteria.

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