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Photon Shielding Features of Quarry Tuff
摘要： Cantera is a quarry tuff widely used in the building industry; in this work the shielding features of cantera were determined. The shielding characteristics were calculated using XCOM and MCNP5 codes for 0.03, 0.07, 0.1, 0.3, 0.662, 1, 2, and 3 MeV photons. With XCOM the mass interaction coefficients, and the total mass attenuation coefficients, were calculated. With the MCNP5 code a transmission experiment was modelled using a point-like source located 42 cm apart from a point-like detector. Between the source and the detector, cantera pieces with different thickness, ranging from 0 to 40 cm were included. The collided and uncollided photon fluence, the Kerma in air and the Ambient dose equivalent were estimated. With the uncollided fluence the linear attenuation coefficients were determined and compared with those calculated with XCOM. The linear attenuation coefficient for 0.662 MeV photons was compared with the coefficient measured with a NaI(Tl)-based γ-ray spectrometer and a 137Cs source.
关键词： XCOM,shielding features,linear attenuation coefficient,Cantera,MCNP5,quarry tuff
更新于2025-09-09 09:28:46
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Comparative Analysis of Various Definitions of the Concept of Effective Atomic Number of Material of a Multicomponent Object
摘要： Comparative analysis is provided for various definitions of the concept of effective atomic number as applied to the material of a multicomponent object. Definitions in which radiation is and is not taken into account explicitly have been considered. Results of calculating the effective atomic numbers of various substances are presented on the basis of the definitions considered. New formal definitions are proposed for this concept when X-raying a multicomponent object with polychromatic radiation.
关键词： X-ray radiation,inspection checks,radiation mass attenuation coefficient,effective atomic number,multicomponent object
更新于2025-09-09 09:28:46
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Cloud Attenuation Prediction Statistics for GEO and NGSO Satellite Communication Systems Operating at Q/V Band and Above
摘要： The employment of extremely high frequency bands (like Q/V and W bands) in the next generation satellite communication system has been proposed for feeder links operation in order to satisfy the ever growing satellite users’ demands. For the feeder links’ reliable performance analysis, the total atmospheric attenuation has to be taken into account. In this paper, a methodology for the estimation of cloud attenuation induced on a satellite slant path, through time series generation of Integrated Liquid Water Content (ILWC), for GEO satellites is presented and modified to consider joint attenuation statistics of cloud attenuation for multiple slant paths and also for the cloud attenuation prediction for NGSO links (MEO and LEO cases). The models are derived from cloud attenuation time series synthesizers, based on stochastic differential equations (SDEs), that incorporate properly the spatial and temporal behavior of ILWC and the time dependence of the elevation angle for NGSO links. Numerical results for GEO, MEO and LEO satellite systems operating at Q and W band are reported. The single link cases are tested with the ITU-R. P. 840-6 model. Interesting conclusions are drawn.
关键词： Cloud attenuation,Feeder Links,diversity gain,NGSO systems,Q and W band,joint cloud attenuation statistics
更新于2025-09-04 15:30:14
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Evaluation of the Level of Transmission of Solar Radiation by Eyeglasses (Spectacles) and its Effects on the Human Eye
摘要： Global atmospheric changes such as depletion of Ozone in the stratosphere and global warming contribute to the average increase of ultraviolet radiation on earth. Protective eyeglasses are normally recommended to safeguard the eyes from the harmful effects of solar radiation. In this paper, twenty (20) pairs of eyeglasses were selected based on systematic random sampling to determine the amount of optical radiation transmission and level of attenuation by eyeglasses, in the wavelength range of 200nm to 900nm using 6405 UV/VIS spectrophotometer. All the eyeglasses were found to transmit a substantial amount of ultraviolet radiation. The transmission of visible light depends on the lens colours. It was discovered that the eyeglasses do not provide complete protection from UV radiation. This shows that the glasses can still pose great danger to human eyes.
关键词： Spectrophotometer,Eyeglasses,Human eye,Percentage transmittance (%T),Optical radiation,Global warming,Depletion of Ozone,Solar radiation,Attenuation
更新于2025-09-04 15:30:14
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Investigation of Material Nonlinearity Measurements Using the Third-Harmonic Generation
摘要： With respect to harmonic generation measurements in isotropic materials, the amplitude of the third-harmonic wave generally depends on both β2 (the square of the second-order nonlinear parameter β) and γ (the third-order nonlinear parameter). Therefore, some care should be taken when measuring these parameters using the third-harmonic amplitude. The purpose of this paper is to investigate detailed theoretical and measurement techniques for the accurate determination of β2 which dominates the third-harmonic amplitude in most biological ?uids and crystalline solids. The theory deals with harmonic generation in materials with cubic nonlinearity and de?nes the formula for measuring β2 with corrections for diffraction and attenuation. These corrections are derived from the Westervelt equation and play an important role in the measurement of nonlinear parameters. The third-harmonic amplitude that varies with the distance in water is obtained for the measurement of β2. β is also measured from the second-harmonic amplitude for comparison. We also con?rm the required input voltage to stably generate the third harmonic and discuss the effects of diffraction and attenuation correction on the β2 determination. The measured β2 in the propagation range of 0.05–0.2 m agrees well with the square of the measured β, revealing that the third-harmonic amplitude is closely related to β2, not γ . This paper covers comprehensive theories, experimentation, and analysis related to the measurement of third-harmonic generation in isotropic media and can be immediately applied to crystalline solids.
关键词： second harmonic,?nite amplitude method,nonlinear parameter,diffraction,quasi-linear solution,Attenuation,third harmonic
更新于2025-09-04 15:30:14
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[IEEE 2018 International Conference on Information , Communication, Engineering and Technology (ICICET) - Pune, India (2018.8.29-2018.8.31)] 2018 International Conference on Information , Communication, Engineering and Technology (ICICET) - Single Image Haze Removal using Image Processing Algorithms
摘要： The pictures taken in awful climatic conditions will adversely influence the picture quality. Fog and haze degrades the picture standard, air-light lessens whiteness of the image and attenuation lessens its contrast. This paper provides colour attenuation prior for haze removal of the image. The main aim is to solve the problem of reduced visibility by excellent image processing strategy and the purpose is to improve the quality of images that lack the shading, complication and depth when perceived by the human eye. By creating a straight model for display the scene extent of the hazy image, we can easily determine the transmission and resume the scene radiance via the atmospheric scattering model.
关键词： colour attenuation,image processing,Haze removal
更新于2025-09-04 15:30:14
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Improved rain-rate and drop-size retrievals from airborne and spaceborne Doppler radar
摘要： Satellite radar remote-sensing of rain is important for quantifying of the global hydrological cycle, atmospheric energy budget, and many microphysical cloud and precipitation processes; however, radar estimates of rain rate are sensitive to assumptions about the rain drop size distribution. The upcoming EarthCARE satellite will feature a 94 GHz Doppler radar alongside lidar and radiometer instruments, presenting opportunities for enhanced global retrievals of the rain drop size distribution. In this paper we demonstrate the capability to retrieve both rain rate and a parameter of the rain drop size distribution from an airborne 94 GHz Doppler radar using CAPTIVATE, the variational retrieval algorithm developed for EarthCARE radar–lidar synergy. For a range of rain regimes observed during the Tropical Composition, Cloud and Climate Coupling (TC4) field campaign in the eastern Pacific in 2007, we explore the contributions of Doppler velocity and path-integrated attenuation (PIA) to the retrievals, and evaluate the retrievals against independent measurements from a second, less attenuated, Doppler radar aboard the same aircraft. Retrieved drop number concentration varied over five orders of magnitude between light rain from melting ice, and warm rain from liquid clouds. Doppler velocity can be used to estimate rain rate over land, and retrievals of rain rate and drop number concentration are possible in profiles of light rain over land; in moderate warm rain, drop number concentration can be retrieved without Doppler velocity. These results suggest that EarthCARE rain retrievals facilitated by Doppler radar will make substantial improvements to the global understanding of the interaction of clouds and precipitation.
关键词： CAPTIVATE,satellite radar remote-sensing,EarthCARE,rain rate,path-integrated attenuation,Doppler radar,retrieval algorithm,drop size distribution
更新于2025-09-04 15:30:14
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Advances in the measurements of the mass attenuation coefficients
摘要： The knowledge of atomic fundamental parameters, such as mass attenuation coefficients or fluorescence yields with low uncertainties, is of decisive importance in elemental quantification involving X‐ray fluorescence analysis techniques. Several databases providing the mass attenuation coefficients are accessible and frequently used within a large community of users. These compilations are most often in good agreement for photon energies in the hard X‐ray ranges. However, they significantly differ for low photon energies and around the absorption edges of the elements. Mass attenuation coefficients of several elements were determined experimentally in the photon energy range from 100 eV to 35 keV by using monochromatized radiation at the SOLEIL synchrotron (France). The application of high‐accuracy experimental techniques resulted in low uncertainty mass attenuation coefficients. The results are compared with tabulated data.
关键词： photon energy,X‐ray fluorescence analysis,mass attenuation coefficients,SOLEIL synchrotron
更新于2025-09-04 15:30:14
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Manufacturing of lens arrays using fast tool servo system based on error correcting algorithm
摘要： Fast tool servo (FTS) system can accurately manufacture the optical components with complex surfaces or microstructures. Due to the influences of moving mass and time constant of drive unit, the output displacement of FTS system will produce the amplitude attenuation and the phase delay, and the machining error will obviously increase in the situation. In this paper, the error correcting algorithm of FTS system is designed, the lead step number and the lead gain are reasonably planned in the error correcting procedure, and the simulating results indicate that the algorithm is simple and the output displacement of FTS system is precise. The effectiveness of designed error correcting algorithm is experimentally verified in the machining procedure of lens array by using FTS system, the machined surface is consistent with the expectant shape referring to the measuring result, and the depth error is 0.06μm in peak-to-valley value.
关键词： Phase delay,Amplitude attenuation,Error correction,Lead compensator,Fast tool servo (FTS)
更新于2025-09-04 15:30:14
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Stuctural, optical and radiation shielding properties of zinc boro-tellurite alumina glasses
摘要： In this work, boro-telluride glasses with additional zinc, aluminum, and alkali–alkaline modifiers have been synthesized using the melt-quenching–annealing method. Six glasses were fabricated with composition of [(60 ? x)B2O3–(10 + x)TeO2–10ZnO–10Al2O3–5Li2O–5MgO] all in mol% and x varied from 0, 10, 20, 30, 40 and 50. The aim of this work is to understand the effect of changing the main glass former from B2O3 → TeO2, to obtain new optical materials. To confirm the amorphous nature of these six glasses, X-ray diffraction was characterized for all six glasses from 10° to 80°. Optical absorption with wavelength range 200–800 nm in room temperature was measured, and the optical absorption coefficient α(λ) calculated to obtain the cutoff wavelength. In addition, gamma photons shielding features of the prepared K1–K6 glasses were evaluated by means of some essential parameters such as mass attenuation coefficients (μ/ρ) and effective atomic number (Zeff) at five energies between 0.356 and 1.33 MeV. No significant difference between the theoretical and simulation μ/ρ values was found. The effective atomic number results indiacte that as the TeO2 content increases, the photons’ attenuation increases. The number of interactions of gamma photons with K6 sample (which contains the maximum amount of TeO2) is relatively high (in comparison to the rest of the samples), which results in more attenuation and thus better shielding features for K6.
关键词： Effective atomic number,Mass attenuation coefficients,Gamma photons shielding,Boro-tellurite glasses,Optical materials
更新于2025-09-04 15:30:14