scholarly journals Effect of Palladium Electrode Patterns on Hydrogen Response Characteristics from a Sensor Based on Ta2O5 Film on SiC at High Temperatures

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5478 ◽  
Author(s):  
Kyeong-Keun Choi ◽  
Seongjeen Kim
Keyword(s):  
Thermal Stability ◽  
High Temperatures ◽  
Breakdown Strength ◽  
Hydrogen Sensor ◽  
Area Ratio ◽  
Hydrogen Sensors ◽  
Dielectric Thin Film ◽  
Response Characteristics ◽  
Ta2o5 Film ◽  
Sensor Structure

Our study aims to fabricate a hydrogen sensor based on thermal stability analysis of Ta2O5 film, and to determine the effect of Pd electrodes on the hydrogen sensor at high temperatures. First, in order to ensure high-temperature stability of silicon carbide (SiC)-based hydrogen sensors, the thermal stability of Ta2O5 dielectric thin film at temperatures above 900 °C was studied. The sensor structure consisted of a metal-insulator-semiconductor (MIS) and a tantalum oxide (Ta2O5) dielectric film was formed by rapid thermal oxidation (RTO). The Ta2O5 film was assessed through SEM, TEM, SIMS, and dielectric breakdown strength to observe thermal stability. Secondly, hydrogen sensors using a SiC substrate were fabricated, with the process considering thermal stability. The response characteristics for hydrogen were evaluated using three types of sensors with different Pd electrode patterns. The patterns of the Pd electrode were designed as squares or grid shapes, and were characterized by 100%, 75%, and 50% area ratios of Pd electrodes covering the Ta2O5 layer. The results showed that the sensor with a 100% area ratio of the Pd electrode had better sensitivity and linear response characteristics compared to sensors with a 50% area ratio of the Pd electrode.

scholarly journals Identification and Characterization of a Poliovirus Capsid Mutant with Enhanced Thermal Stability

2018 ◽  
Vol 93 (6) ◽  
Author(s):  
Y Nguyen ◽  
Palmy R. Jesudhasan ◽  
Elizabeth R. Aguilera ◽  
Julie K. Pfeiffer
Keyword(s):  
Thermal Stability ◽  
High Temperatures ◽  
Oral Route ◽  
Mutant Virus ◽  
Single Amino Acid ◽  
Bacterial Surface ◽  
Virus Particles ◽  
Heat Resistant ◽  
Viral Particles ◽  
Very High

ABSTRACTEnteric viruses, including poliovirus, are spread by the fecal-oral route. In order to persist and transmit to a new host, enteric virus particles must remain stable once they are in the environment. Environmental stressors such as heat and disinfectants can inactivate virus particles and prevent viral transmission. It has been previously demonstrated that bacteria or bacterial surface glycans can enhance poliovirus virion stability and limit inactivation from heat or bleach. While investigating the mechanisms underlying bacterially enhanced virion thermal stability, we identified and characterized a poliovirus (PV) mutant with increased resistance to heat inactivation. The M132V mutant harbors a single amino acid change in the VP1 capsid coding that is sufficient to confer heat resistance but not bleach resistance. Although the M132V virus was stable in the absence of bacteria or feces at most temperatures, M132V virus was stabilized by feces at very high temperatures. M132V PV had reduced specific infectivity and RNA uncoating compared with those of wild-type (WT) PV, but viral yields in HeLa cells were similar. In orally inoculated mice, M132V had a slight fitness cost since fecal titers were lower and 12.5% of fecal viruses reverted to the WT. Overall, this work sheds light on factors that influence virion stability and fitness.IMPORTANCEViruses spread by the fecal-oral route need to maintain viability in the environment to ensure transmission. Previous work indicated that bacteria and bacterial surface polysaccharides can stabilize viral particles and enhance transmission. To explore factors that influence viral particle stability, we isolated a mutant poliovirus that is heat resistant. This mutant virus does not require feces for stability at most temperatures but can be stabilized by feces at very high temperatures. Even though the mutant virus is heat resistant, it is susceptible to inactivation by treatment with bleach. This work provides insight into how viral particles maintain infectivity in the environment.

scholarly journals Investigations of Different Ion Intercalations on the Performance of FBG Hydrogen Sensors Based on Pt/MoO3

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4775 ◽  
Author(s):  
Gaopeng Wang ◽  
Shiwen Yang ◽  
Jixiang Dai ◽  
Yutang Dai ◽  
Tong Zou ◽  
...  
Keyword(s):  
Layer Structure ◽  
Hydrogen Sensor ◽  
Hydrogen Sensors ◽  
Practical Application ◽  
Crystalline Layer ◽  
Optimal Amount ◽  
Hydrogen Sensing ◽  
Sensing Material ◽  
Ionic Bonds ◽  
Ion Species

α-MoO3 has been used as a hydrogen sensing material due to its excellent properties and unique crystalline layer structure. However, the low repeatability of α-MoO3 based hydrogen sensor restricts its practical application. In this paper, the effect of intercalated ion species and the amount in α-MoO3 is experimentally investigated and discussed. It is concluded that the repeatability of the sensor depends on the radius of intercalated ions and amount of ionic bonds. The optimal ion species is Na+ and the optimal amount of precursor is 1 mmol.

scholarly journals Use of Grafted Voltage Stabilizer to Enhance Dielectric Strength of Cross-Linked Polyethylene

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 176 ◽  
Author(s):  
Wei Dong ◽  
Xuan Wang ◽  
Bo Tian ◽  
Yuguang Liu ◽  
Zaixing Jiang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Breakdown Strength ◽  
Dielectric Strength ◽  
Voltage Stabilizer ◽  
Cross Linking ◽  
Practical Application ◽  
Electrical Tree ◽  
Research Goal ◽  
The Stability ◽  
New Research

Aromatic voltage stabilizers can improve the dielectric properties of cross-linked polyethylene (XLPE); however, their poor compatibility with XLPE hinders their practical application. Improving the compatibility of aromatic voltage stabilizers with XLPE has, therefore, become a new research goal. Herein 1-(4-vinyloxy)phenylethenone (VPE) was prepared and characterized. It can be grafted onto polyethylene molecules during the cross-linking processes to promote stability of the aromatic voltage stabilizers in XLPE. Fourier transform infrared spectroscopy confirmed that VPE was successfully grafted onto XLPE, and effectively inhibited thermal migration. Thermogravimetric analysis showed that the grafted VPE/XLPE composite exhibits a better thermal stability than a VPE/PE blend composite. Evaluation of the electrical properties showed that the breakdown strength and electrical tree initiation voltage of the VPE/XLPE composite were increased by 15.5% and 39.6%, respectively, when compared to those of bare XLPE. After thermal aging, the breakdown strength and electrical tree initiation voltage of the VPE/XLPE composite were increased by 9.4% and 25.8%, respectively, in comparison to those of bare XLPE, which indicates that the grafted voltage stabilizer can effectively inhibit its migration and enhance the stability of the composite material.

Improving the Performance of Hydrogen Sensors with Novel TiO2 Nanotube Arrays Hybrid Structure

2019 ◽  
Vol 803 ◽  
pp. 120-123
Author(s):  
Xiong Bang Wei ◽  
Guo Dong Lv ◽  
Xiao Hui Yang ◽  
Tao Wu ◽  
Dong Shi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Research Work ◽  
High Sensitivity ◽  
Hydrogen Sensor ◽  
Hybrid Structure ◽  
Nanotube Arrays ◽  
Hybrid Nanostructure ◽  
Hydrogen Sensors ◽  
Novel Structure ◽  
Titanium Wire

In this paper, a kind of novel TiO2 nanotube arrays (TNTs) hybrid structure was presented to improve the performance of hydrogen sensors. In this novel structure, palladium functionalized TNTs hybrid nanostructure supported on titanium wire. TNTs arrays was prepared by anodizing Ti wire using a standard electrochemical procedure. Pd nanomaterials were deposited on TNTs. Optimized experiments showed the hydrogen sensor supported on titanium wire showed a good response time of 8 s and high sensitivity of 94.8% at 1.9 vol% H2 at room temperature (25 °C). The research work revealed potential good hydrogen sensitivity of this kind of hybrid nanostructure.

Wearable colorimetric sensing fiber based on polyacrylonitrile with PdO@ZnO hybrids for the application of detecting H2 leakage

2020 ◽  
Vol 90 (19-20) ◽  
pp. 2198-2211
Author(s):  
Sung-Ho Hwang ◽  
Young Kwang Kim ◽  
Soon Moon Jeong ◽  
Changsoon Choi ◽  
Ka Young Son ◽  
...  
Keyword(s):  
Color Change ◽  
Hydrogen Sensor ◽  
Hydrogen Gas ◽  
Hybrid Nanoparticles ◽  
Hydrogen Sensors ◽  
Colorimetric Sensing ◽  
Hydrogen Sensing ◽  
Detection Systems ◽  
Sensing Material ◽  
Novel Method

A colorimetric hydrogen sensor has great potential for accurately detecting and monitoring the leakage of hydrogen gas on account of its fast color change in contact with hydrogen gas. However, for the practical application of the sensor, such as in gas detection systems in clothing, the flexibility and stability of the sensor need to be improved. Here, we present a novel method to fabricate a flexible colorimetric hydrogen sensor with the stable embedment of sensing material. To improve the flexibility and stability of the sensor, polyacrylonitrile nanofiber containing palladium oxide and zinc oxide hybrid nanoparticles was prepared by electrospinning. The flexible colorimetric hydrogen sensor can detect 1000 ppm hydrogen gas with excellent selectivity within 2 min. We also suggest film and yarn-type flexible colorimetric hydrogen sensors for industrial and wearable applications. A laminating process was used to prepare the film. In contrast, twisting and polydimethylsiloxane coating were used to prepare the yarn-type flexible colorimetric hydrogen sensor. Compared with a flexible colorimetric hydrogen-sensing nanofiber, the film and yarn show identical sensitivity for detecting a hydrogen leakage. These applications of hydrogen sensors could be a new insight into the design of a flexible sensor for detecting hydrogen leakage with the naked eye.

Assessment of the thermal stability of anodic alumina membranes at high temperatures

2008 ◽  
Vol 111 (2-3) ◽  
pp. 542-547 ◽  
Author(s):  
L. Fernández-Romero ◽  
J.M. Montero-Moreno ◽  
E. Pellicer ◽  
F. Peiró ◽  
A. Cornet ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Temperatures ◽  
Anodic Alumina ◽  
Alumina Membranes ◽  
Thermal Stability Of

Thermal Stability and Oxidation Resistance of Pt–10 Al–4Cr Alloy at Super-High Temperatures

2006 ◽  
Vol 66 (3-4) ◽  
pp. 127-135 ◽  
Author(s):  
R. N. Mahaptara ◽  
S. K. Varma ◽  
C. S. Lei
Keyword(s):  
Thermal Stability ◽  
Oxidation Resistance ◽  
High Temperatures
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