Local Heat Energy Transport Analyses in Gainn/gan Heterostructure by Microscopic Raman Imaging Employing Simultaneous Irradiation of Two Laser Beams

2021 ◽  
Author(s):  
Shungo Okamoto ◽  
Naomichi Saito ◽  
Kotaro Ito ◽  
Bei Ma ◽  
Ken Morita ◽  
...  
Keyword(s):  
Energy Transport ◽  
Local Heat ◽  
Heat Energy ◽  
Raman Imaging ◽  
Laser Beams ◽  
Simultaneous Irradiation ◽  
Gan Heterostructure

scholarly journals Local Heat Energy Transport Analyses in Gallium-Indium-Nitride/Gallium Nitride Heterostructure by Microscopic Raman Imaging Exploiting Simultaneous Irradiation of Two Laser Beams

2020 ◽  
Author(s):  
Shungo Okamoto ◽  
Naomichi Saito ◽  
Kotaro Ito ◽  
Bei Ma ◽  
Ken Morita ◽  
...  
Keyword(s):  
Heat Generation ◽  
Energy Transport ◽  
Indium Nitride ◽  
Local Heat ◽  
Heat Energy ◽  
Raman Imaging ◽  
Gallium Indium Nitride ◽  
Simultaneous Irradiation ◽  
Different Characteristics ◽  
532 Nm

Abstract Local heat transport in two GaxIn1-xN/GaN-heterostructures on sapphire substrates is investigated by microscopic Raman imaging using two lasers of 532 nm (Raman observation) and 325 nm (heat generation and Raman observation), which enables the separation of heat generation and Raman observation positions. It is found that E2(high) and A1(LO) modes of the Ga0.84In0.16N layer exhibit mutually different characteristics, which indicates the analysis of the occupation of the A1(LO) mode is available. E2(high) mode of the GaN layer observed by the 532-nm laser reveals that the transport of the heat energy generated in the Ga0.84In0.16N layer to the GaN under layer is blocked in the high-density area of misfit dislocation in the vicinity of the heterointerface.

scholarly journals The relationship between the local temperature and the local heat flux within a one-dimensional semi-infinite domain of heat wave propagation

2003 ◽  
Vol 2003 (4) ◽  
pp. 173-179 ◽  
Author(s):  
Vladimir V. Kulish ◽  
Vasily B. Novozhilov
Keyword(s):  
Heat Flux ◽  
Energy Transport ◽  
Local Heat ◽  
Local Temperature ◽  
Convolution Integral ◽  
Infinite Domain ◽  
One Dimensional ◽  
Local Heat Flux ◽  
The Relationship ◽  
Hyperbolic Heat Equation

The relationship between the local temperature and the local heat flux has been established for the homogeneous hyperbolic heat equation. This relationship has been written in the form of a convolution integral involving the modified Bessel functions. The scale analysis of the hyperbolic energy equation has been performed and the dimensionless criterion for the mode of energy transport, similar to the Reynolds criterion for the flow regimes, has been proposed. Finally, the integral equation, relating the local temperature and the local heat flux, has been solved numerically for those processes of surface heating whose time scale is of the order of picoseconds.

Management of Local Heat Poverty in Households – on the Selected Example

2021 ◽  
pp. 1-15
Author(s):  
Katarzyna ŚWIERSZCZ
Keyword(s):  
Energy Security ◽  
Local Governments ◽  
Social Research ◽  
Local Heat ◽  
Heat Energy ◽  
European Countries ◽  
Effective Management ◽  
Energy Poverty

The reason for writing the article is the phenomenon of heat energy poverty among households. This problem is experienced both in Poland and other more or less developed European countries. Its main cause is three elements: economic, technical and social. Research shows that local governments responsible for the effective management of energy security are beginning to notice the problem of heat poverty in local terms.

scholarly journals Unsteady Coupled Moisture and Heat Energy Transport through an Exterior Wall Covered with Vegetation

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4422
Author(s):  
Leopold Škerget ◽  
António Tadeu ◽  
João Almeida
Keyword(s):  
Heat Flux ◽  
Differential Equations ◽  
Energy Transport ◽  
Building Envelope ◽  
Heat Energy ◽  
Brick Wall ◽  
Exterior Wall ◽  
Concrete Wall ◽  
Area Index ◽  
Green Wall

A mathematical model that governs unsteady coupled moisture and heat energy transport through an exterior wall covered with vegetation is described. The unknown temperature and moisture content of the plants and canopy air are represented by a system of nonlinear ordinary differential equations (ODEs). The transport of moisture and heat through the support structure, which includes insulation and soil layers, is defined in a series of nonlinear partial differential equations (PDEs). After setting out the model, this article presents and discusses a set of numerical applications. First, a simplified system consisting of a brick wall covered with climbing vegetation is used to study the role of individual variables (e.g., wind speed, minimum stomatal internal leaf resistance, leaf area index, and short-wave extinction coefficient) on the hygrothermal behaviour of the green wall. Thereafter, more complex green wall systems comprising a bare concrete wall, mortar, cork-based insulation (ICB), soil and vegetation are used to evaluate the influence of the thermal insulation and substrate layers on the heat flux distribution over time at the interior surface of the wall, and on the evolution of the relative humidity, water content, and temperature throughout the cross section of the green wall. The numerical experiments proved that vegetation can effectively reduce exterior facade surface temperatures, heat flux through the building envelope and daily temperature fluctuations.

scholarly journals Energy transport analysis in a Ga0.84In0.16N/GaN heterostructure using microscopic Raman images employing simultaneous coaxial irradiation of two lasers

2020 ◽  
Vol 116 (14) ◽  
pp. 142107
Author(s):  
Shungo Okamoto ◽  
Naomichi Saito ◽  
Kotaro Ito ◽  
Bei Ma ◽  
Ken Morita ◽  
...  
Keyword(s):  
Energy Transport ◽  
Transport Analysis ◽  
Gan Heterostructure

scholarly journals Recent experiments on the hydrodynamics of laser-produced plasmas conducted at the PALS laboratory

2007 ◽  
Vol 25 (1) ◽  
pp. 127-141 ◽  
Author(s):  
D. BATANI ◽  
R. DEZULIAN ◽  
R. REDAELLI ◽  
R. BENOCCI ◽  
H. STABILE ◽  
...  
Keyword(s):  
Energy Transport ◽  
Experimental Results ◽  
Analytical Models ◽  
Laser Beams ◽  
Lateral Expansion ◽  
Iodine Laser ◽  
One Dimensional

We present a series of experimental results, and their interpretation, connected to various aspects of the hydrodynamics of laser produced plasmas. Experiments were performed using the Prague PALS iodine laser working at 0.44 μm wavelength and irradiances up to a few 1014W/cm2. By adopting large focal spots and smoothed laser beams, the lateral energy transport and lateral expansion have been avoided. Therefore we could reach a quasi one-dimensional regime for which experimental results can be more easily and properly compared to available analytical models.

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