Electronic structure of GaAs/A1GaAs quantum double rings in lateral electric field

A three-dimensional model of GaAs/A1GaAs quantum double rings in the lateral static electric field is investigated theoretically. The eigenvalue problem with the effective-mass approximation is solved by means of the finite-element method. The energy levels and wave functions of quantum-confined electrons and heavy holes are obtained and show an agreement with our previous theoretical and experimental studies. It is shown in the approximation of neglecting the Coulomb attraction between the electron and heavy hole that a relatively large Stark shift of exciton emission of 4 meV is attainable with an applied electric field of 0.7 kV/cm.

Thermal-optic tuning cascaded double ring optical sensor based on wavelength interrogation

Based on the Vernier effect of the cascaded double ring resonator(CDRR) sensor,a sensor consisting of a microfluidic control system,a sensing ring,and a reference ring with a micro-heater for thermal tuning is proposed in this paper.In wavelength interrogation,a broadband spectrometer or a large tunable range laser is not required.The shift of the output spectrum caused by the refractive index change of the sample is converted into the change of the electric power by the thermal tuning heater.Due to the Vernier effect,the sensitivity of the sensor is 20 times higher than that of the single ring.The spectral envelope of the thermal-optic tuning of the sensor was fitted by a Gaussian function in the wavelength range of8 nm.The experimental results showed that the sensitivity was 33.703 W/RIU,and the limit of detection was 1.34×10-5 RIU.

Modelling of Wideband Concentric Ring Frequency Selective Surface for 5G Devices

Frequency selective surfaces(FSSs)play an important role in wireless systems as these can be used as filters,in isolating the unwanted radiation,in microstrip patch antennas for improving the performance of these antennas and in other 5G applications.The analysis and design of the double concentric ring frequency selective surface(DCRFSS)is presented in this research.In the sub-6 GHz 5G FR1 spectrum,a computational synthesis technique for creating DCRFSS based spatial filters is proposed.The analytical tools presented in this study can be used to gain a better understanding of filtering processes and for constructing the spatial filters.Variation of the loop sizes,angles of incidence,and polarization of the concentric rings are the factors which influence the transmission coefficient as per the thorough investigation performed in this paper.A novel synthesis approach based on mathematical equations that may be used to determine the physical parameters ofDCRFSSbased spatial filters is presented.The proposed synthesis technique is validated by comparing results from high frequency structure simulator(HFSS),Ansys electronic desktop circuit editor,and an experimental setup.Furthermore,the findings acquired from a unit cell are expanded to a 2×2 array,which shows identical performance and therefore proves its stability.

Estimation and inter-comparison of infiltration models in the agricultural area of the Mitidja Plain, Algeria

Infiltration is an important part of the hydrological cycle, and it is one of the main abstractions accounted for in the rainfall-runoff modeling. The main purpose of this study is to compare the infiltration models that were used to assess the infiltration rate of the Mitidja Plain in Algeria. Field infiltration tests were conducted at 40 different sites using a double ring infiltrometer. Five statistical comparison criteria including root mean squared error(RMSE), normalized root mean squared error(NRMSE), coefficient of correlation(CC), Nash-Sutcliffe efficiency(NSE), and Kling-Gupta efficiency(KGE) were used to determine the best performing infiltration model and to confirm anomalies between predicted and observed values. Then we evaluated performance of five models(i.e., the Philip model, Kostiakov model, Modified Kostiakov model, Novel model, and Horton model) in simulating the infiltration process based on the adjusted performance parameters cited above. Results indicated that the Novel model had the best simulated water infiltration process in the Mitidja Plain in Algeria. However, the Philip model was the weakest to simulate the infiltration process. The conclusion of this study can be useful for estimating infiltration rate at various sites using a Novel model when measured infiltration data are not available and are useful for planning and managing water resources in the study area.

Instrumentation of Infiltrometers with Arduino to Determine Soil Water Infiltration Rate

The intense mobilization of the soil inappropriately causes a reduction in the percentage of macropores and in the rate of soil water infiltration with reduction of crop yield. Due to the difficulty of using the Muntz concentric ring method, researchers have used mathematical models to estimate infiltration based on soil physical parameters such as, soil texture that does not reflect physical reality in relation to infiltration rate, leading to errors. To automate the use of the infiltrometer ring method, there are no hydrometers that record small flows in non-pressurized hydraulic systems, making it difficult to automate the method for field determination. For this purpose, six Muntz double rings were instrumented with an electromechanical system coupled to the “Tipin Buked” (weighbridge) with the ability to record flows from 8 cm3∙minute−1 on a memory card. The results indicate that the models of the regression equations describe 93% to 99% of the real values, showing the accuracy of the equipment. This work aimed to modify the Muntz method to reduce field work and automate the determination of water infiltration rate in the soil.

Calibration of the Infiltration Rate Curve from the LN Trend Line at Eight Sites of Interest, Based on Infiltration Tests Carried out

The purpose of this research is to demonstrate that a calibration curve can be obtained that can be used for any infiltration test, with the double ring method, as well as an equation that helps speed up data processing. The experimentation was carried out in eight points in Nicaragua, of which five were distributed in Managua and three in Rivas-Nandaime. These results can be used for purposes of other studies of interest. As a result, a calibration curve is obtained, and an expression equal to is deduced, which will be the equation to determine the average infiltration of a field test occupying the double ring, for a total of 7 hours. And it is from the result that the texture of the soil can be determined by means of the indicator table. The basic methodology allowed analyzing the data since they are obtained, processed and analyzed, resulting in the calibration curve for infiltration tests. Finally, an equation was determined from the averages of the processed data, resulting in a correlation of 0.9976, above 0.5, which means it is very high and reliable.

Interzeolite transformation from FAU to CHA and MFI zeolites monitored by UV Raman spectroscopy

As a powerful and sensitive tool for the characterization of zeolite building units,UV Raman spectroscopy has been used to monitor interzeolite transformation from FAU to CHA and MFI zeolites.The results show that the behavior of double 6-membered rings(D6Rs)in the FAU zeolite framework plays an important role during the formation of the target product in the interzeolite transformation.For the transformation of FAU to CHA,because both zeolites contain the same D6R units,direct transformation occurs,in which the D6Rs were largely unchanged.In contrast,for the transformation of FAU to MFI,the D6Rs can be divided into two single 6-membered rings(S6Rs),which further assembled into the MFI structure.In this crystallization,5-membered rings(5Rs)are only observed in the MFI framework formation,suggesting that the basic building units in the transformation of FAU to MFI are S6Rs rather than 5Rs.These insights will be helpful for further understanding of the interzeolite transformation.

Spin transport properties in double quantum rings connected in series

A new model of metal/semiconductor/metal double-quantum-ring connected in series is proposed and the transport properties in this model are theoretically studied. The results imply that the transmission coefficient shows periodic variations with increasing semiconductor ring size. The effects of the magnetic field and Rashba spin-orbit interaction on the transmission coefficient for two kinds of spin state electrons are different. The number of the transmission coefficient peaks is related to the length ratio between the upper arm and the half circumference of the ring. In addition, the transmission coefficient shows oscillation behavior with enhanced external magnetic field, and the corresponding average value is related to the two leads＇ relative position.