Photothermoelectric resistance effect observed in Ti/SiO2/Si structure induced by 10.6 μm CO2 laser

2020 ◽  
Vol 34 (34) ◽  
pp. 2050391
Author(s):  
Xu Sun ◽  
Pengfei Zhu ◽  
Kun Zhu ◽  
Yunxia Ping ◽  
Chaomin Zhang ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Motion Direction ◽  
Change Rate ◽  
Continuous Irradiation ◽  
Drift Motion ◽  
Diffusion Motion ◽  
Si Films ◽  
Value Changes ◽  
And Diffusion ◽  
Resistance Value

A novel photothermoelectric resistance effect of the Ti/SiO2/Si films induced by 10.6 [Formula: see text]m CO2 laser is discovered and investigated. The transient response of the resistance is observed and analyzed in this work. Under the continuous irradiation of the laser, the thermal resistance value changes with the irradiating time and gradually reaches a stable saturation. The results indicate that the rise time of thermal resistance is shortened and its change rate increased as laser power gets higher. The inner battery of the ohmmeter exerts the positive or negative bias voltage, causing the diffusion motion direction of the hot electrons to be opposite or the same direction with the drift motion, which can increase or decrease the thermal resistance value. Those experimental phenomena are explained by the drift and diffusion motion of the electrons. Based on the results, the Ti/SiO2/Si structure is an attractive candidate for thermal effect devices.

Thermal Characterization of Two Opposing Carbon Nanotube Arrays Using Diffraction-Limited Infrared Microscopy

2005 ◽  
Author(s):  
Xuejiao Hu ◽  
Matt Panzer ◽  
Kenneth E. Goodson
Keyword(s):  
Thermal Resistance ◽  
Contact Region ◽  
Thermal Characterization ◽  
Interface Structure ◽  
Infrared Microscopy ◽  
Carbon Nanotube Arrays ◽  
Cnt Arrays ◽  
Significant Temperature ◽  
Resistance Value

Due to their extremely high thermal conductivity, carbon nanotubes (CNTs) have received many research interests for thermal management applications. An advanced thermal interface structure made by two opposing, partially over-lapped CNT arrays is designed for thermally connecting two contact surfaces. The performance of this interface structure is thermally characterized using diffraction-limited infrared microscopy. Significant temperature discontinuities are found at the end of the CNT-CNT contact region, which indicates a large thermal resistance between CNTs. Due to this inter-tube resistance, the thermal performance of the CNT-based interface structure is far below expectation, with a thermal resistance value of about 3.8 × 10−4 K·m2/W. Possible mechanisms of heat transfer between CNTs, which result in the large inter-tube resistance, are discussed.

scholarly journals Circuit Topologies for MOS-Type Gas Sensor

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 525
Author(s):  
Javier Cervera Gómez ◽  
Jose Pelegri-Sebastia ◽  
Rafael Lajara
Keyword(s):  
Gas Sensors ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Electrical Characteristics ◽  
Freedom Of Choice ◽  
Power Noise ◽  
Food And Drink ◽  
Value Changes ◽  
Resistance Value ◽  
Conditioning Circuit

Metal Oxide Semiconductor or MOS-type gas sensors are resistive sensors which can detect different reducible or volatile gases in atmospheres with oxygen. These gas sensors have been used in different areas such as food and drink industries or healthcare, among others. In this type of sensor, the resistance value changes when it detects certain types of gases. Due to the electrical characteristics, the sensors need a conditioning circuit to transform and acquire the data. Four different electronic topologies, two different MOS-type gas sensors, and different concentrations of a gas substance are presented and compared in this paper. The study and experimental analysis of the properties of each of the designed topology allows designers to make a choice of the best circuit for a specific application depending on the situation, considering the required power, noise, linearity, and number of sensors to be used. This study will give more freedom of choice, the more adequate electronic conditioning topology for different applications where MOS-type sensors are used, obtaining the best accuracy.

The Durability of Flame Retardant and Thermal Protective Cotton Fabrics during Domestic Laundering

2012 ◽  
Vol 441 ◽  
pp. 255-260 ◽  
Author(s):  
Wei Bang Chen ◽  
Ying Ying Wan ◽  
Fei Que ◽  
Xue Mei Ding
Keyword(s):  
Thermal Resistance ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Protective Clothing ◽  
Flame Retardants ◽  
Thermal Protection ◽  
Water Vapor Permeability ◽  
Vapor Permeability ◽  
Before And After ◽  
Resistance Value

Flame retardant fabrics have been broadly used for protective clothing, which have strictly requirements on both flame retardancy and thermal protection. Usually, domestic laundering will be carried out frequently to clean these protective garments. However, little research on the performance durability of this type of fabrics after domestic laundering has been reported. This paper selected fabrics of 8 types of cotton and its blend fibers, which were treated with flame retardants Pyrovatex CP, Proban, CFR-201, SCJ-968 respectively. The damaged length, after flame time, after glow time, TPP value, thermal resistance value, weight, thickness, air permeability and water vapor permeability (WVP) of the samples were measured before and after 15 cycles domestic laundering cycles. Results show that the flame retardancy of the 8 fabrics reduce with launderings as measured by the increase in damaged length and after glow time. The TPP increase probably resulted from the increase in the thickness and thermal resistance of the finished fabrics. Domestic laundering resulted in only a slight change in the comfort properties of the fabrics.

scholarly journals Measuring the Rate of Heat Loss Across Selected Building Materials

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Genesis Zambrano ◽  
Keyword(s):  
Thermal Resistance ◽  
Heat Loss ◽  
Thermal Performance ◽  
Building Materials ◽  
Thermal Conductance ◽  
High Thermal Resistance ◽  
Resistance Value

The rate of heat loss is analyzed for three materials: glass, brick and wood. To do this, the initial and final temperatures are set to 75℉ and 100℉, respectively, and the dimensions of each material are chosen to be 5ft by 5ft with a thickness of 2 inches. The objective of this paper is to see which material is best for insulating heat, thus enhancing the thermal performance of a building. Results from this study suggest that glass and brick have a higher rate of heat loss (high thermal conductance values and low thermal resistance values) compared to wood and are therefore poor insulators whereas wood, with a lower rate of heat loss (low thermal conductance value and a high thermal resistance value) serves as a better insulator.

scholarly journals Method for Determining the Optimum Insulation Thickness of the Plaster Tow Material: Influence of the Heat Exchange Coefficient in Transient Regime

2021 ◽  
Vol 16 (3) ◽  
pp. 53
Author(s):  
Papa Touty TRAORE ◽  
Fatimata BA ◽  
Babou DIONE ◽  
Moussa DIENG
Keyword(s):  
Heat Exchange ◽  
Thermal Resistance ◽  
Numerical Method ◽  
Transient Regime ◽  
Exchange Coefficient ◽  
Heat Exchange Coefficient ◽  
Insulation Thickness ◽  
Resistance Value ◽  
Optimum Insulation Thickness

In this paper, we have applied a numerical method to determine the optimum insulation thickness of the tow plaster plane material. The influence of the exchange coefficients at the level of the two faces of the material has been highlighted. The optimum insulation thickness of the material is at the area where the thermal resistance value of the material is the maximum. We added the relative thermal resistance to show how the optimum insulation thickness changes when the exchange coefficients change values.

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