scholarly journals Spectral tomographic analysis of Bremsstrahlung X-rays generated in a laser-produced plasma

2016 ◽  
Vol 34 (4) ◽  
pp. 645-654 ◽  
Author(s):  
Y.J. Rhee ◽  
S.M. Nam ◽  
J. Peebles ◽  
H. Sawada ◽  
M. Wei ◽  
...  
Keyword(s):  
Experimental Data ◽  
Variational Principle ◽  
Energy Distribution ◽  
Tomographic Reconstruction ◽  
Spectral Characteristics ◽  
X Rays ◽  
Temperature Model ◽  
New Approach ◽  
Tomographic Analysis ◽  
Two Temperature

AbstractA new approach is proposed to analyze Bremsstrahlung X-rays that are emitted from laser-produced plasmas (LPP) and are measured by a stack type spectrometer. This new method is based on a spectral tomographic reconstruction concept with the variational principle for optimization, without referring to the electron energy distribution of a plasma. This approach is applied to the analysis of some experimental data obtained at a few major laser facilities to demonstrate the applicability of the method. Slope temperatures of X-rays from LPP are determined with a two-temperature model, showing different spectral characteristics of X-rays depending on laser properties used in the experiments.

scholarly journals Simulation of laser ablation of metals for nanoparticles production

2016 ◽  
Vol 41 ◽  
pp. 1660143 ◽  
Author(s):  
R. V. Davydov ◽  
V. I. Antonov ◽  
T. I. Davydova
Keyword(s):  
Experimental Data ◽  
Laser Ablation ◽  
Femtosecond Laser Ablation ◽  
Hydrodynamic Equations ◽  
Temperature Model ◽  
Wide Range ◽  
Simulation Results ◽  
Range Equation ◽  
Two Temperature ◽  
Good Agreement

In this paper a mathematical model for femtosecond laser ablation of metals is proposed, based on standard two-temperature model connected with 1D hydrodynamic equations. Wide-range equation of state has been developed. The simulation results are compared with experimental data for aluminium and copper. A good agreement for both metals with numerical results and experiment shows that this model can be employed for choosing laser parameters to better accuracy in nanoparticles production by ablation of metals.

NUMERICAL SIMULATION OF HIGH-TEMPERATURE IONIZED AIR RADIATION ON UNSTRUCTURED GRIDS

2009 ◽  
Vol 23 (03) ◽  
pp. 281-284
Author(s):  
XUEQIANG LIU ◽  
YIBIN WANG ◽  
YIZHAO WU
Keyword(s):  
Experimental Data ◽  
High Temperature ◽  
Reference Data ◽  
Unstructured Grids ◽  
Temperature Model ◽  
Gamma Prime ◽  
Ionized Air ◽  
Volume Method ◽  
Equilibrium Effect ◽  
Two Temperature

A numerical method which is based on unstructured grids to compute high-temperature ionized air radiation is described. The multi-species N-S equations are used and the chemical model includes 11 species ( O 2, N 2, O , N , NO , NO +, N +, O +, N +2, O +2, e -) and 20 reactions. For simulating thermal non-equilibrium effect, the two-temperature model is considered. The finite volume method (FVM) is used for spatial and directional discretization for the RTE on unstructured grids. The code can deal with different kinds of species and radiative bands. Particularly, the Delta, Epsilon, Beta prime and Gamma prime bands of NO are considered in this paper. The numerical results of MESES-C for hypersonic flow with high-temperature ionized radiation are shown, and compared well with the reference data and experimental data.

Double Beam Spectrophotometer for Simultaneous Measurements of the Upwelling Sea Radiance and the Incident See Irradiance

2019 ◽  
pp. 105-110
Author(s):  
Mikhail Yongon Lee ◽  
Sergei V. Fedorov
Keyword(s):  
Spectral Characteristics ◽  
Sea Surface ◽  
Input Port ◽  
Silicon Photodiode ◽  
New Approach ◽  
Surface Irradiance ◽  
Simultaneous Measurements ◽  
Double Beam

The article describes the structure and the operation principle of the spectrophotometer developed on the basis of a compact rapid monochromator with one input port and two output ports and a radiometric unit where upwelling radiation radiance and sea surface irradiance channels are located. A new approach to measurements of spectral characteristics of upwelling radiation of sea based on combination of advantages of a double beam photometer with a photomultiplier and a directreading photometer with a highstability silicon photodiode for its absolute adjustment in energy units is implemented.

GENERAILIZED TWO-TEMPERATURE MODEL FOR COUPLED PHONONS IN NANOSIZED GRAPHENE

2018 ◽  
Author(s):  
Meng An ◽  
Qichen Song ◽  
Xiaoxiang Yu ◽  
Han Meng ◽  
Dengke Ma ◽  
...  
Keyword(s):  
Temperature Model ◽  
Two Temperature

Theoretical Interpretation of High-Performance Chromatographic Data for a Heterogeneous Series of Compounds

1992 ◽  
Vol 57 (1) ◽  
pp. 33-45
Author(s):  
Vladimír Jakuš
Keyword(s):  
Experimental Data ◽  
High Performance ◽  
Theoretical Interpretation ◽  
Retention Data ◽  
Theoretical Evaluation ◽  
New Approach ◽  
Free Energy Of Solvation ◽  
Rp Hplc ◽  
Mobile Phases ◽  
Reversed Phases

A new approach to theoretical evaluation of the Gibbs free energy of solvation was applied for estimation of retention data in high-performance liquid chromatography on reversed phases (RP-HPLC). Simple and improved models of stationary and mobile phases in RP-HPLC were employed. Statistically significant correlations between the calculated and experimental data were obtained for a heterogeneous series of twelve compounds.

scholarly journals Introducing the HD+B model for pulsar wind nebulae: a hybrid hydrodynamics/radiative approach

2020 ◽  
Vol 494 (3) ◽  
pp. 4357-4370
Author(s):  
B Olmi ◽  
D F Torres
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Theoretical Modelling ◽  
X Rays ◽  
Pulsar Wind Nebulae ◽  
New Approach ◽  
Energy Gamma ◽  
Radiative Model ◽  
Pulsar Wind

ABSTRACT Identification and characterization of a rapidly increasing number of pulsar wind nebulae is, and will continue to be, a challenge of high-energy gamma-ray astrophysics. Given that such systems constitute -by far- the most numerous expected population in the TeV regime, such characterization is important not only to learn about the sources per se from an individual and population perspective, but also to be able to connect them with observations at other frequencies, especially in radio and X-rays. Also, we need to remove the emission from nebulae in highly confused regions of the sky for revealing other underlying emitters. In this paper, we present a new approach for theoretical modelling of pulsar wind nebulae: a hybrid hydrodynamic-radiative model able to reproduce morphological features and spectra of the sources, with relatively limited numerical cost.

A Theoretical Analysis of CO2 Absorption in Sun Versus Shade Leaves

1978 ◽  
Vol 100 (1) ◽  
pp. 20-24 ◽  
Author(s):  
R. H. Rand
Keyword(s):  
Experimental Data ◽  
Quantitative Estimate ◽  
Geometric Model ◽  
Model Parameters ◽  
Co2 Absorption ◽  
Temperature Model ◽  
Spongy Mesophyll ◽  
One Dimensional ◽  
Mesophyll Tissue ◽  
Shade Leaves

A one-dimensional, steady-state, constant temperature model of diffusion and absorption of CO2 in the intercellular air spaces of a leaf is presented. The model includes two geometrically distinct regions of the leaf interior, corresponding to palisade and spongy mesophyll tissue, respectively. Sun, shade, and intermediate light leaves are modeled by varying the thicknesses of these two regions. Values of the geometric model parameters are obtained by comparing geometric properties of the model with experimental data of other investigators found from dissection of real leaves. The model provides a quantitative estimate of the extent to which the concentration of gaseous CO2 varies locally within the leaf interior.

scholarly journals A Two-Temperature Model for LBVs

2004 ◽  
Vol 2004 (IAUS226) ◽  
pp. 506-510
Author(s):  
J. H. Guo ◽  
Y. Li ◽  
H. G. Shan
Keyword(s):  
Temperature Model ◽  
Two Temperature
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