Lattice Dynamics Study on the Thermal Conduction Properties of Single Atomic Layer Films (I)—Formulas for Phonon Linewidth and Thermal Conductivity

2020 ◽  
Vol 10 (06) ◽  
pp. 140-145
Author(s):  
建平 黄
Keyword(s):  
Thermal Conductivity ◽  
Lattice Dynamics ◽  
Thermal Conduction ◽  
Atomic Layer ◽  
Conduction Properties ◽  
Phonon Linewidth

Phonons and Thermal Conductivity in Skutterudite Thermoelectrics

2003 ◽  
Vol 793 ◽  
Author(s):  
C. A. Kendziora ◽  
G. S. Nolas
Keyword(s):  
Thermal Conductivity ◽  
Thermal Conduction ◽  
Screening Tool ◽  
Crucial Step ◽  
Theoretical Predictions ◽  
Filled Skutterudites ◽  
Scattering Spectra ◽  
Polarized Raman ◽  
Raman Scattering Spectra ◽  
Conduction Properties

ABSTRACTWe study Raman phonon vibrations and relate them to thermal conductivity for empty and filled skutterudites designed for thermoelectric applications, where low thermal conduction is critical. Polarized Raman scattering spectra of crystallite and polycrystalline samples are compared with theoretical predictions and analyzed in comparison to the thermal conduction properties. Our emphasis is on the CoSb3 skutterudite and its filled derivatives, including materials with Ge, Sn, and La in the cages. We observe a strong correlation between aspects of the Raman spectrum and low thermal conductivity. This presents Raman spectroscopy as a characteristic screening tool for potential thermoelectrics and is a crucial step toward predicting lattice thermal conductivities.

scholarly journals Ultrasensitive nano-optomechanical force sensor operated at dilution temperatures

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Francesco Fogliano ◽  
Benjamin Besga ◽  
Antoine Reigue ◽  
Laure Mercier de Lépinay ◽  
Philip Heringlake ◽  
...  
Keyword(s):  
Thermal Conduction ◽  
Photon Counting ◽  
Force Sensor ◽  
Lateral Force ◽  
Oscillation Period ◽  
The Road ◽  
Field Gradients ◽  
Concomitant Reduction ◽  
Generic Strategy ◽  
Conduction Properties

AbstractCooling down nanomechanical force probes is a generic strategy to enhance their sensitivities through the concomitant reduction of their thermal noise and mechanical damping rates. However, heat conduction becomes less efficient at low temperatures, which renders difficult to ensure and verify their proper thermalization. Here we implement optomechanical readout techniques operating in the photon counting regime to probe the dynamics of suspended silicon carbide nanowires in a dilution refrigerator. Readout of their vibrations is realized with sub-picowatt optical powers, in a situation where less than one photon is collected per oscillation period. We demonstrate their thermalization down to 32 ± 2 mK, reaching very large sensitivities for scanning probe force sensors, 40 zN Hz−1/2, with a sensitivity to lateral force field gradients in the fN m−1 range. This opens the road toward explorations of the mechanical and thermal conduction properties of nanoresonators at minimal excitation level, and to nanomechanical vectorial imaging of faint forces at dilution temperatures.

Influence of the Material and Thickness of the Specimen on an Infrared Stress Image

2004 ◽  
Vol 261-263 ◽  
pp. 1641-1646
Author(s):  
Kenji Machida ◽  
Mamtimin Gheni
Keyword(s):  
Thermal Conductivity ◽  
Hybrid Method ◽  
Thermal Conduction ◽  
Crack Problem ◽  
High Stress ◽  
High Accuracy ◽  
Problem Analysis ◽  
Principal Stresses ◽  
Distribution Form ◽  
Stress Components

The thickness dependency of the temperature image obtained by an infrared thermography was investigated using specimens with three kinds of materials and four kinds of the thickness of the specimen. Only the sum of the principal stresses which is the first invariant of stress tensor is measured, and it is impossible to measure individual stress components directly. Then, the infrared hybrid method was developed to separate individual stress components. Although the form of the contour line of low stress side differs greatly, the distribution form of high stress side was considerably alike. The stress intensity factor of material with low thermal conductivity can be estimated with high accuracy by the infrared hybrid method. On the crack problem, it was elucidated that the influence of thermal conduction is large and an inverse problem analysis is required.

Research on Temperature Characteristic of Porous Cement Concrete

2011 ◽  
Vol 374-377 ◽  
pp. 2105-2109
Author(s):  
Li Qun Hu ◽  
Wei Si Ma ◽  
Hong Qing Hou
Keyword(s):  
Wind Speed ◽  
Moisture Content ◽  
Thermal Conduction ◽  
Temperature Characteristic ◽  
Specimen Thickness ◽  
Cement Concrete ◽  
Molding Process ◽  
Pressing Method ◽  
Island Effect ◽  
Conduction Properties

This research aims to study the temperature characteristic of porous cement concrete as an alternative pavement that can help to mitigate urban heat island effect, and all the benefits it can provide, along with several offspring. Three experiments conducted in this research focus on the effect of specimen thickness,moisture content and wind speed on the thermal conduction properties of porous cement concrete. Isostatic pressing method is adopted in the molding process of specimens and reserved holes method is utilized to measure the internal temperature of the specimens.The data presented in this paper explains the tend of thermal conduction properties accompanying the increase of specimen thickness,moisture content and wind speed.

Thermal conduction characteristics of silicone composites including ultrasonic-treated graphite

2021 ◽  
pp. 002199832110595
Author(s):  
Weontae Oh ◽  
Jong-Seong Bae ◽  
Hyoung-Seok Moon
Keyword(s):  
Thermal Conductivity ◽  
Ultrasonic Treatment ◽  
Thermal Conduction ◽  
Light Emitting Diode ◽  
Thermal Interface Material ◽  
Ultrasonic Power ◽  
Lighting System ◽  
Thermal Interface ◽  
Light Emitting ◽  
Inorganic Oxides

The microstructural change of graphite was studied after ultrasonic treatment of the graphite. When the graphite solution was treated with varying ultrasonic power and time, the microstructure changed gradually, and accordingly, the thermal conductivity characteristics of the composite containing the as-treated graphite was also different with each other. Thermal conductivity showed the best result in the silicone composite containing graphite prepared under the optimum condition of ultrasonic treatment, and the thermal conductivity of the composite improved proportionally along with the particle size of graphite. When the silicone composite was prepared by using a mixture of inorganic oxides and graphite rather than graphite alone, the thermal conductivity of the silicone composite was further increased. A silicone composite containing graphite was used for LED (light emitting diode) lighting system as a thermal interface material (TIM), and the temperature elevation due to heat generated, while the lighting was actually operated, was analyzed.

scholarly journals Thermal conduction properties of microcracked media: Accounting for the unilateral effect

2019 ◽  
Vol 347 (12) ◽  
pp. 944-952
Author(s):  
Sharan Raj Rangasamy Mahendren ◽  
Hélène Welemane ◽  
Olivier Dalverny ◽  
Amèvi Tongne
Keyword(s):  
Thermal Conduction ◽  
Conduction Properties

scholarly journals Design and Implementation of a Laboratory Equipment for Studying Heat Transfer by Conduction

2019 ◽  
Vol 11 (1) ◽  
pp. 153-156
Author(s):  
István Padrah ◽  
Judit Pásztor ◽  
Rudolf Farmos
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Conduction ◽  
Thermal Conduction ◽  
Transfer Mechanism ◽  
Measuring Instrument ◽  
Heat Transfer Mechanism ◽  
Laboratory Equipment ◽  
Insulating Materials ◽  
Design And Implementation

Abstract Thermal conduction is a heat transfer mechanism. It is present in our everyday lives. Studying thermal conductivity helps us better understand the phenomenon of heat conduction. The goal of this paper is to measure the thermal conductivity of various materials and compare results with the values provided by the manufacturers. To achieve this we assembled a measuring instrument and performed measurements on heat insulating materials.

Enhanced thermal conductivity of epoxy composites by constructing thermal conduction networks via adding hybrid alumina filler

2021 ◽  
Author(s):  
Zhong‐Yu Wang ◽  
Xiao‐Nan Zhou ◽  
Zi‐Xuan Li ◽  
Song‐Song Xu ◽  
Liu‐Cheng Hao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Conduction ◽  
Epoxy Composites ◽  
Enhanced Thermal Conductivity
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