scholarly journals Angular Dependence of Ionoluminescence for Silica Case

2020 ◽  
Keyword(s):  
Angular Distribution ◽  
Angular Dependence ◽  
Sample Surface ◽  
Measuring System ◽  
Observation Angle ◽  
Mutual Arrangement ◽  
Model Assumption ◽  
Fast Ions ◽  
Large Observation ◽  
Good Agreement

The paper deals with angular dependence of ionoluminescence from transparent glossy silica samples. We measured silica ionoluminescence spectra at wavelength range of 400–700 nm for different projectiles (H1+, H2+, He+ 210 and 420 keV) and registered two most common intensive emission peaks (blue with a maximum at 456 nm and red one at 645 nm). To study luminescent angular dependence, the behavior of the blue peak maximum as a function of observation angle in the range of 0–70° was examined, namely, the indicatrix at the wavelength of 456 nm was found. The intensity corresponding to ionoluminescent indicatrices were found to be higher with respect to values from Lambertian angular distribution reaching approximately 20 % at large observation angles. We also calculated angular distribution of light above the sample surface taking into account refraction and reflection at the solid-ambient interface. The results obtained were in a good agreement with silica ionoluminescence experimental data for the average indicatrix curve. The latter indicates that the model assumption (luminescent light generated by fast ions within silica is unpolarized and isotropic) is correct. It was demonstrated that geometry of the experiment is very important, i.e., considering the light collected by the measuring system in a certain solid angle, one has to take into account that mutual arrangement of the sample and detector can distort angular distribution. The refraction at the border between a sample and vacuum (or air) strongly influences the luminescent light angular distribution.

Experimental investigation and modelling of light scattering in a-Si:H solar cells deposited on glass/ZnO:Al substrates

2002 ◽  
Vol 715 ◽  
Author(s):  
J. Krc ◽  
M. Zeman ◽  
O. Kluth ◽  
F. Smole ◽  
M. Topic
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Solar Cells ◽  
Angular Distribution ◽  
Light Scattering ◽  
Optical Model ◽  
Distribution Functions ◽  
Interface Roughness ◽  
Scattering Parameters ◽  
Good Agreement

AbstractThe descriptive scattering parameters, haze and angular distribution functions of textured ZnO:Al transparent conductive oxides with different surface roughness are measured. An approach to determine the scattering parameters of all internal interfaces in p-i-n a-Si:H solar cells deposited on the glass/ZnO:Al substrates is presented. Using the determined scattering parameters as the input parameters of the optical model, a good agreement between the measured and simulated quantum efficiencies of the p-i-n a-Si:H solar cells with different interface roughness is achieved.

Study of the 1459-keV level in 19F by the 19F(p,p′γ)19F reaction

1970 ◽  
Vol 48 (7) ◽  
pp. 827-833 ◽  
Author(s):  
S. T. Lam ◽  
A. E. Litherland ◽  
J. J. Simpson
Keyword(s):  
Angular Distribution ◽  
Single Crystal ◽  
Linear Polarization ◽  
Proton Energy ◽  
Branching Ratios ◽  
Mixing Ratio ◽  
Γ Ray ◽  
Good Agreement

The 1459-keV level of 19F was populated by the 19F(p,p′γ)19F reaction at a proton energy of 2.78 MeV. The E2/M1 mixing ratio for the 1459 → 110 keV transition was determined to be [Formula: see text] from a combination of the γ-ray angular distribution and linear polarization and the nuclear lifetime. The γ-ray angular distribution was measured with a coaxial Ge(Li) detector and the γ-ray linear polarization with a planar Ge(Li) detector. The corresponding E2 and M1 transition strengths for a lifetime of 0.084 ± 0.020 ps are found to be [Formula: see text] and 0.10 ± 0.03 W.u. respectively. They are in good agreement with the particle–hole calculations of Benson and Flowers. The branching ratios of the 1459-keV level agree well with those of Poletti et al. The γ-ray transitions from the 1459-keV level provide a good example for demonstrating the usefulness of a single crystal Ge(Li) polarimeter.

Computer studies of fast ion trajectories in crystals

1968 ◽  
Vol 46 (6) ◽  
pp. 503-516 ◽  
Author(s):  
D. V. Morgan ◽  
D. van Vliet
Keyword(s):  
Large Angle ◽  
Classical Dynamics ◽  
Perfect Lattice ◽  
Fast Ions ◽  
Angle Scattering ◽  
Initial Work ◽  
Fast Ion ◽  
Thermal Vibrations ◽  
Computer Studies ◽  
Good Agreement

A computer program has been developed which follows the trajectories of fast ions in crystals, based on the assumption of classical dynamics and binary collisions. Initial work has been directed at various aspects of proton channeling in copper in the energy range 5–500 keV. The critical angle and distance of closest approach in a perfect lattice have been evaluated for both rows and planes and compare well with the predictions of the continuum model as developed by Lindhard (1965). We also discuss the overlap of close-packed rows and planes, and the modifications necessary to the basic theory when thermal vibrations are introduced. Experiments have been simulated directly by obtaining a statistical analysis of the velocity distribution of protons reflected from a (100) face of copper and transmitted through a thin (~1800 Â) crystal. In reflection, distinct minima were obtained along directions corresponding to close-packed rows and planes, in good agreement with experimental "blocking patterns" (Nelson 1967a). Transmission patterns also revealed a lack of large-angle scattering parallel to close-packed planes, analogous to the white arms observed experimentally with thinner crystals.

scholarly journals Characterization and Application of a Grazing Angle Objective for Quantitative Infrared Reflection Microspectroscopy

1995 ◽  
Vol 49 (3) ◽  
pp. 354-360 ◽  
Author(s):  
Stephen V. Pepper
Keyword(s):  
Angular Dependence ◽  
Grazing Angle ◽  
Fresnel Reflection ◽  
Angular Aperture ◽  
Incident Intensity ◽  
Specular Reflectance ◽  
Fresnel Reflection Coefficient ◽  
Infrared Reflection ◽  
Good Agreement

A grazing angle objective on an infrared microspectrometer is studied for quantitative spectroscopy by considering the angular dependence of the incident intensity within the objective's angular aperture. The assumption that there is no angular dependence is tested by comparing the experimental reflectance of Si and KBr surfaces with the reflectance calculated by integrating the Fresnel reflection coefficient over the angular aperture under this assumption. Good agreement was found, indicating that the specular reflectance of surfaces can straightforwardly be quantitatively integrated over the angular aperture without considering nonuniform incident intensity. This quantitative approach is applied to the thickness determination of dipcoated Krytox on gold. The infrared optical constants of both materials are known, allowing the integration to be carried out. The thickness obtained is in fair agreement with the value determined by ellipsometry in the visible. Therefore, this paper illustrates a method for more quantitative use of a grazing angle objective for infrared reflectance microspectroscopy.

The measuring system for monitoring the microarc heating process during surface hardening of steel products

2021 ◽  
pp. 33-39
Author(s):  
Makar S. Stepanov ◽  
rina G. Koshlyakova
Keyword(s):  
Heat Treatment ◽  
Mathematical Model ◽  
Electric Current ◽  
Measurement Method ◽  
Sample Surface ◽  
Steel Sample ◽  
Measuring System ◽  
Heating Process ◽  
Carbon Powder ◽  
Measured Temperature

The accelerated heat treatment during steel products hardening technology has been investigated. The possibility of measuring the temperature of steel products by thermoelectric platinum-platinum-rhodium thermocouple under microarc heating conditions is analyzed. During the experiments, working junctions of two S-type thermocouples: working and standard, were coined into the sample surface at the same level. The free thermocouples ends were connected to a digital multimeter and a personal computer. It was determined that 5 factors affect the measurement results: the electric current strength in the circuit, carbon powder, calibration, number of repeated measurement cycles, and a thermocouple copy. When planning the experiment, the concept of conducting a step-by-step nested experiment was used. Variance analysis method was used to process the experimental results. The measurement method precision parameters were calculated: repeatability and reproducibility. A linear mathematical model linking the measurement method reproducibility index with the measured temperature value has been obtained. A linear mathematical model is obtained that relates the reproducibility index of the measurement method to the measured temperature value. A measuring system for the experimental determination of the temperature of a steel sample is proposed and its application is justified for different electric current densities on the sample surface and varying duration of microarc heating. The possibilities of selecting and controlling the microarc heating modes depending on the required temperature of the heat treatment of the steel product are determined.

scholarly journals Cloud Effective Emissivity Retrievals Using Combined Ground-Based Infrared Cloud Measuring Instrument and Ceilometer Observations

2018 ◽  
Vol 10 (12) ◽  
pp. 2033
Author(s):  
Lei Liu ◽  
Ting Zhang ◽  
Yi Wu ◽  
Zhencong Niu ◽  
Qi Wang
Keyword(s):  
Measuring System ◽  
Measuring Instrument ◽  
Effective Emissivity ◽  
Retrieval Method ◽  
Clear Sky ◽  
Inversion Procedure ◽  
The Mean ◽  
And Performance ◽  
Emissivity Measurements ◽  
Good Agreement

In this paper, a new inversion procedure for cloud effective emissivity retrievals using a combined ground-based infrared cloud measuring instrument with ceilometer was developed. A quantitative sensitivity and performance analysis of the proposed method was also provided. It was found that the uncertainty of the derived effective emissivity was mainly associated with errors on the measurement radiance, the simulated radiance of clear sky and blackbody cloudy sky. Furthermore, the retrieval at low effective emissivity was most sensitive to the simulated clear sky radiances, whereas the blackbody cloudy sky radiance was the prevailing source of uncertainty at high emissivity. This newly proposed procedure was applied to the measurement taken in the CMA Beijing Observatory Station from November 2011 to June 2012 by the whole-sky infrared cloud-measuring system (WSIRCMS) and CYY-2B ceilometer. The cloud effective emissivity measurements were in good agreement with that of the MODIS/AQUA MYD06 Collection 6 (C6) cloud products. The mean difference between them was 0.03, with a linear correlation coefficient of 0.71. The results demonstrate that the retrieval method is robust and reliable.

Measurement of Cyclic Biaxial Elastoplastic Stresses at Notch Roots

1995 ◽  
Vol 62 (3) ◽  
pp. 646-653 ◽  
Author(s):  
C. H. Yang ◽  
W. N. Sharpe
Keyword(s):  
Constitutive Models ◽  
Measuring System ◽  
Cyclic Plasticity ◽  
Elastoplastic Behavior ◽  
Cyclic Stresses ◽  
Fine Grain ◽  
Notch Geometry ◽  
Cyclic Plasticity Model ◽  
Elastoplastic Constitutive Model ◽  
Good Agreement

A straightforward procedure is demonstrated for measuring local cyclic elastoplastic biaxial stresses at notch roots. First, the biaxial cyclic strains are measured over short gage lengths (150 or 200 micrometers) with a laser-based strain measuring system. Then, cyclic stresses are computed from those measured strains by using an elastoplastic constitutive model. The material selected for this study is HY-80 steel which has a fine grain size and is isotropic. Double-notched specimens were prepared with two different notch geometries: a U-shaped notch with a 4.76 mm radius and a V-shaped notch with a 1.0 mm radius. Two thicknesses, 2.54 and 12.7 mm, were tested for each notch geometry to produce four different amounts of notch constraint. The results of cyclic biaxial strain measurements show good reproducibility. Stress computations based on two different constitutive models were used to compute stresses for the first cycle and a stable cycle. One of the constitutive models is the classical J2flow theory and the other is a two-surface cyclic plasticity model. The results computed using these two models show good agreement with each other. The measured stresses show the effect of constraint on the elastoplastic behavior at notch roots under cyclic loading conditions.

scholarly journals Impact Energy and Angular Dependence of L X-ray Emission from a Thick Polycrystalline Tungsten Element Induced by 15–25 keV Electrons

Atoms ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 82
Author(s):  
Bhupendra Singh ◽  
Suman Prajapati ◽  
Bhartendu K. Singh ◽  
R. Shanker
Keyword(s):  
Angular Dependence ◽  
Impact Energy ◽  
Intensity Ratio ◽  
Incidence Angle ◽  
Angular Variation ◽  
Measured Intensity ◽  
Polycrystalline Tungsten ◽  
Simulation Results ◽  
The Impact ◽  
Good Agreement

The impact energy and angular dependence of L X-rays of a thick polycrystalline tungsten (W; atomic number, Z = 74) target induced by 15–25 keV electrons has been measured at different angles varying from 15° to 75° at intervals of 5° using a Si PIN photodiode detector. The variation of measured relative intensity of Ll, Lα, Lβ and Lγ characteristic lines as a function of incidence angle is found to be anisotropic and the measured variation compares well with the PENELOPE simulation results. The angular variation of intensity ratio of Ll/Lα and Lβ/Lα shows anisotropic distribution, whereas the angular variation of the Lγ/Lα ratio exhibits almost isotropic distribution within the uncertainty of measurements. These measured ratios are found to be in good agreement with Monte Carlo (MC) calculations. The measured intensity ratios of Lβ/Lα and Lγ/Lα at a given incidence angle show a linear dependence with impact energy and exhibit good agreement with simulation results; however, the measured intensity ratio of Ll/Lα shows a non-linear variation with the impact energy and yields poor agreement with theoretical calculations.

scholarly journals An investigation of the neutrons produced in the deuteron-deuteron reaction

1948 ◽  
Vol 195 (1040) ◽  
pp. 123-134 ◽  
Keyword(s):  
Angular Distribution ◽  
Neutron Emission ◽  
Photographic Plate ◽  
Deuteron Beam ◽  
Forward Direction ◽  
Maximum Energy ◽  
Neutron Spectra ◽  
Precision Determination ◽  
Good Agreement

Some properties of the 2 1 H + 2 1 H = 2 He+ 1 0 n reaction are investigated by the photographic plate technique for a bombarding deuteron energy of 920 keV. Thick deuterium targets only are used, and the following quantities measured : ( a ) The Q value—found to be (3·23 ± 0·02) MeV. ( b ) The neutron spectra at various angles of neutron emission. ( c ) The angular distribution of the neutrons. The problems arising in the application of the technique to the precision determination of neutron energy are discussed and the previous precision determination of the Q value by Bonner is criticized. The present results are in good agreement with the Q value of the reaction 2 1 H + 2 1 H = 3 1 H + 1 1 H and the maximum energy of the 3 1 H β-spectrum. The neutron spectra are in accord with those calculated from the ballistics of the reaction and the known excitation function. The neutron angular distribution shows a marked maximum in the forward direction and a minimum at 90° to the deuteron beam.

Research on Wash Wave in Shallow Water Caused by Ship Moving at High Speed

2012 ◽  
Vol 212-213 ◽  
pp. 104-107
Author(s):  
Hui Deng ◽  
Zhi Hong Zhang ◽  
Tao Miao ◽  
Jian Nong Gu
Keyword(s):  
Numerical Simulation ◽  
Shallow Water ◽  
Water Wave ◽  
High Speed ◽  
Pressure Variation ◽  
Measuring System ◽  
Ship Model ◽  
Wave Elevation ◽  
Supercritical Speed ◽  
Good Agreement

Based on the theory of shallow-water wave, the theoretical model was established for calculating wash wave caused by ship moving at subcritical and supercritical speed. Wave elevation and pressure variation were obtained by numerical simulation, and their features were analyzed. A measuring system of wash wave and pressure variation was developed, and wave elevation and pressure variation induced by a towed ship model were measured. A good agreement existed between the calculated with experimental results.

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