The Transmission Spectra of Some Potential Radome Materials for Millimetre and Near Millimetre Wavelength Applications

Author(s):  
J. R. Birch ◽  
J. D. Dromey ◽  
R. L. T. Street
Keyword(s):  
2020 ◽  
Vol 92 (1) ◽  
pp. 10901
Author(s):  
Saloua El Asri ◽  
Hamid Ahamdane ◽  
Lahoucine Hajji ◽  
Mohamed El Hadri ◽  
Moulay Ahmed El Idrissi Raghni ◽  
...  

Forsterite single phase powder Mg2SiO4 was synthesized by sol–gel method alongside with heat treatment, using two different cation alkaline salts MCl as mineralizers (M = Na, K) with various mass percentages (2.5, 5, 7.5, and 10 wt.%). In this work, we report on the effect of the cation type and the added amount of used mineralizer on microstructure and electrical conductivity of Mg2SiO4. The formation of forsterite started at 680–740  °C and at 630–700  °C with KCl and NaCl respectively, as shown by TG-DTA and confirmed by XRD. Furthermore, the Fourier transform infrared (FTIR) transmission spectra indicated bands corresponding to vibrations of forsterite structure. The morphology and elemental composition of sintered ceramics were examined by SEM-EDX analyses, while their densities, which were measured by Archimedes method, increased with addition of both alkaline salts. The electrical measurements were performed by Complex Impedance Spectroscopy. The results showed that electrical conductivity increased with the addition of both mineralizers, which was higher for samples prepared with NaCl than those prepared with KCl.


Author(s):  
S. A. Sadovnikov

Introduction: Successful monitoring of environmental parameters requires the development of flexible software complexes with evolvable calculation functionality. Purpose: Developing a modular system for numerical simulation of atmospheric laser gas analysis. Results: Based on differential absorption method, a software system has been developed which provides the calculation of molecular absorption cross-sections, molecular absorption coefficients, atmospheric transmission spectra, and lidar signals. Absorption line contours are calculated using the Voigt profile. The prior information sources are HITRAN spectroscopic databases and statistical models of the distribution of temperature, pressure and gas components in the atmosphere. For modeling lidar signals, software blocks of calculating the molecular scattering coefficient and aerosol absorption/scattering coefficients were developed. For testing the applicability of various laser sources in the problems of environmental monitoring of the atmosphere, a concentration reconstruction error calculation block was developed for the atmospheric gas components, ignoring the interfering absorption of laser radiation by foreign gases. To verify the correct functioning of the software, a program block was developed for comparing the results of the modeling of atmospheric absorption and transmission spectra by using the standard SPECTRA information system. The discrepancy between the calculation of the atmospheric transmission spectra obtained using the developed system as compared to the SPECTRA results is less than 1%. Thus, a set of the presented program blocks allows you to carry out complex modeling of remote atmospheric gas analysis. Practical relevance: The software complex allows you to rapidly assess the possibilities of using a wide range of laser radiation sources for the problems of remote gas analysis.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1043 ◽  
Author(s):  
Aritra Ghosh ◽  
Abdelhakim Mesloub ◽  
Mabrouk Touahmia ◽  
Meriem Ajmi

Buildings consume considerable amount of energy to maintain comfortable interior. By allowing daylight, visual comfort inside a building is possible which can enhance the occupant’s health, mood and cognitive performance. However, traditional highly transparent windows should be replaced with semitransparent type window to attain a comfortable daylight inside a building. Evaluation of visual comfort includes both daylight glare and colour comfort analysis. Building integrated photovoltaic (BIPV) type windows are promising systems and can possess a range of semitransparent levels depending on the type of PV used. In this work, the semitransparent Perovskite BIPV windows was investigated by employing daylight glare analysis for an office building located in Riyadh, KSA and three wavelength dependent transmission spectra for colour comfort analysis. The results showed that the transmissions range between 50–70% was optimum for the comfortable daylight for south facing vertical pane BPV-windows. However, excellent colour comfort was attained for the transmission range of 90% which provided glare issues. Colour comfort for 20% transparent Perovskite was compared with contemporary other type of PV which clearly indicated that wavelength dependent transmittance is stronger over single value transmittance.


2012 ◽  
Vol 20 (1) ◽  
Author(s):  
Ł. Chrobak ◽  
M. Maliński ◽  
K. Strzałkowski ◽  
J. Zakrzewski

AbstractThe paper presents results of computations of the energy efficiency of the cobalt luminescence in ZnSe:Co determined by the photoacoustic method. The transmission spectra, photoacoustic experimental and theoretical spectra, and the frequency dependence on the photoacoustic amplitude characteristics are presented. From them, the energy efficiency of Co2+ the near infrared luminescence (3200 nm) was computed in the frame of new proposed photoacoustic model of computations of the luminescence energy efficiency.


1981 ◽  
Vol 64 (12) ◽  
pp. C-178-C-180 ◽  
Author(s):  
Binod Kumar ◽  
N. Fernelius ◽  
J. A. Detrio

1998 ◽  
Vol 15 (1) ◽  
pp. 21-23 ◽  
Author(s):  
Dong-bin Mei ◽  
Peng Dong ◽  
Hong-qiang Li ◽  
Bing-ying Cheng ◽  
Dao-zhong Zhang

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