Abstract This work has reported the optical switches based semiconductor optical amplifiers (SOAs) for the performance of the characteristics enhancement by using various electrical pulse generators. ...Max. Q, bit error rate (BER) after light detector, max. signal power (MSP), min. noise power (MNNP), and total optical power after power combiner based SOAs with various pulse generators are simulated and clarified. Return to zero (RZ) pulse code has clarified max Q than other pulse generators. The max output signal power is improved with Gaussian pulse in compared to other pulse generators. Triangle/RZ pulse generators have presented better total optical power than other proposed generators.
Plastic film mulching has been widely used to increase soil temperature in areas with a cold spring. Reliable simulation of mulched soil surface temperature is important for initial growth of spring ...crops. The hybrid Root Zone Water Quality-Simultaneous Heat and Water (RZ-SHAW) model and the Denitrification-Decomposition (DNDC) model use different approaches to quantify the effect of plastic film mulching on soil temperature. A two-year field study was conducted to compare the performance of the RZ-SHAW model and DNDC model for simulating the 5-cm soil temperature (T5) under varying plastic film mulching coverages during seedling emergence of spring maize. Three treatments were used in this study: no mulching (PM0), full plastic film mulch (PM100), and partial plastic film mulch with 60 % coverage, i.e. 60 cm width of plastic every meter (PM60). Compared with no mulching, PM100 and PM60 treatments enhanced daily maximum and average T5 (2.53℃ and 1.25℃, respectively; p < 0.05) while not affecting the diurnal sinusoidal phase change of T5 (2.45℃ and 1.21℃, respectively; p < 0.05). The RZ-SHAW model was robust for T5 simulation under mulching condition with RMSE and NSE ranged from 2.01℃ to 2.51℃ and 0.68 to 0.84, respectively, while the DNDC model failed to predict T5 for mulched soil with RMSE and NSE ranged from 2.79℃ to 4.33℃ and 0.25 to 0.46, respectively. Employing Tms (air temperature between plastic film and soil surface) to replace soil surface temperature may be one reason for the poor T5 simulation of DNDC in mulched plots. By contrast, the RZ-SHAW model ran a complete calculation for heat and vapour transfer within the mulched layer, which robustly simulated atmosphere–soil surface temperature gradient in the plant canopy, surface covering, and soil surface in a broader range of climatic conditions. Additionally, the longwave radiation reflected back to the soil surface by the plastic, which was not considered by DNDC model, was important and enhanced T5 simulation performance for RZ-SHAW under mulching condition. It suggested to imbed the SHAW module into DNDC for a sufficiently precise simulation of soil temperature and gas emission.
The Luttinger Hamiltonian model is employed to investigate spin–orbit magneto-transport in an indium arsenide-based p-type double top-gate device with Rashba and Zeeman effects. The analyses focus ...particularly on the effects of the top-gate width (L), distance between the top gates (d), potential energy amplitude (U0), and asymmetry of the top-gate width on the formation of electron-like quasi-bound states and hole-like quasi-bound states within the conduction channel. The results confirm the feasibility of controlling the transport characteristics of the charged carriers through an appropriate setting of the gate width and gate potential energy. The findings provide useful insights into the complex transport dynamics of p-type semiconductor systems and have potential implications for device engineering.
•The Luttinger Hamiltonian model is employed to investigate spin–orbit magneto-transport in an InAs-based p-type double top-gate device.•The analyses focus particularly on the effects of the top-gate width (L), distance between the top gates (d), potential energy amplitude (U0), and asymmetry of the top-gate width on the formation of electron-like quasi-bound states and hole-like QBSs.•The results confirm the feasibility of controlling the transport characteristics of the charged carriers through an appropriate setting of the gate width and gate potential energy.
ABSTRACT
It has been shown that during the burst of accretion activity observed in UX Ori-type star RZ Psc in 2013, the accretion rate increased approximately by an order of magnitude. This means ...that the accretion process at the late stages of the pre-main sequence evolution is very unstable. Using the spectra obtained during this episode, we have studied the magnetospheric emission in the H α line. Models of magnetospheric accretion are calculated to obtain the parameters of the magnetosphere from this observation. In this work, we have taken into account the influence of the recombination delay effect during gas motion in the stellar magnetosphere. The accounting for this effect and the presence of the magnetospheric absorption in the IR Ca ii triplet lines and its absence in D Na i resonance lines allowed us to place a lower limit on the temperature in the magnetosphere at $\approx 10\, 000$ K, which significantly improved precision of our estimate of accretion rate. According to the best-fitting model, the logarithm of accretion rate is $\log \dot{M} = -10.1\pm 0.3$ ($\dot{M} \approx 7\times 10^{-11}\ \mathrm{M_\odot \, yr^{-1}}$) and the inclination angle of RZ Psc is 43° ± 3°. It is less than the inclination, typical for the UX Ori stars (about 70°), that explains the weak photometric variability of this star. Using the obtained accretion rate and magnetosphere radius, we estimate the strength of the dipole component of the magnetic field of RZ Psc ≈ 0.1 kGs.
We report the systematic analysis of the X-ray observations of the ultraluminous X-ray source
XMMU J122939.7+075333
located in the globular cluster
RZ 2109
in the Virgo galaxy
NGC 4472
. The ...inclusion of observations and time intervals ignored in previous works and the careful selection of extraction regions and energy bands have allowed us to identify new flaring episodes, in addition to those that made it one of the best black hole candidates in globular clusters. Although most observations are too short and sparse to recognize a regular pattern, the spacing of the three most recent X-ray flares is compatible with a recurrence time of ∼34 h. If confirmed by future observations, this behavior together with the soft spectrum of the X-ray flares would be strikingly similar to the quasiperiodic eruptions recently discovered in galactic nuclei. Following one of the possible interpretations of these systems and of a peculiar class of extragalactic X-ray transients, we explore the possibility that XMMU J122939.7+075333 might be powered by the partial disruption of a white dwarf by an intermediate-mass (
M
∼ 700
M
⊙
) black hole.
Abstract This work demonstrated the distributed feedback laser grating order effects on optical system in the presence of NRZ-RZ line coding schemes. Max lighted signal form power variations are ...studied with spectral base wavelength band variations through optical fiber based on first various distributed based band feedback laser (DFB) grating order. The total lighted form base power band through optical fiber based on first different DFB laser grating order is estimated. The max electrical base signal band power form variations with spectral base frequency form band variations through photo-detector based on various DFB laser grating order is demonstrated. Total electrical based power band form through photo-detector based on various DFB laser grating order is also clarified. Max base band power form band amplitude with time through photo-detector based on different DFB laser grating order is clarified. Max Q base band form is studied numerically with DFB laser grating order variations.
Abstract This study has clarified various RZ Percentage Duty Cycle Coding with NRZ modulation Technique Signature on The Fiber System Performance. The total form lighted/electrical power after linear ...measured multimode fiber/FSO channel measured based different RZ percentage duty cycle coding with the assistance of NRZ modulation techniques is performed. The electrical/lighted form measured power after APD receiver with linear multimode fiber/FSO channel measured based different RZ percentage base band form duty cycle coding with the assistance of NRZ modulation techniques is demonstrated. The lighted based band form can be used for the modulation of the based band electrical signal form based on the RZ percentage duty cycle coding with the assistance of NRZ for both linear measured multimode fiber and FSO measured channel.
•A Parallel distributed HPC framework (RS-DPCF) was developed for the RZ-SHAW model.•RS-DPCF requires less time and effort in calibrating parameters for multiple sites.•RS-DPCF provides faster ...calibration for the RZ-SHAW model with scalability.•Multi-threading delivers better efficiency compared to multi-processing for RZ-SHAW.
The winter/spring season in cold climate regions has been recognized as a critical period for cropland nutrient loss and greenhouse gas emissions and has been predicted to be vulnerable to climate change. Agricultural system models serve as essential tools in anticipating potential outcomes. The RZ-SHAW model, combining the Simultaneous Heat and Water Model (SHAW) with the Root Zone Water Quality Model 2 (RZWQM2), comprehensively describes snow and soil freezing dynamics. Showing promising results in simulating winter frost dynamics it, however, remains computationally intensive. High-performance computing has been recognized as a promising approach to reducing simulation runtimes. A modularized parallel distributed high-performance computing (HPC) framework (RS-DPCF) with both multi-threading (MT) and multi-processing (MP) capability was developed for RZ–SHAW calibration and simulation. Two case studies demonstrated that the developed RS-DPCF program could significantly reduce RZ–SHAW calibration time, allow improved computation resource scalability, and perform field-scale simulations of overwintering conditions for multiple croplands across Canada. For the RZ–SHAW model, MT provided a parallel-computing efficiency superior to that of MP.
A polarization division multiplexed (PDM) microwave photonic link for the millimeter (MM)-wave signal with hybrid modulation scheme is proposed in this paper, which is based on the combination of ...quadrature amplitude modulation, multi-pulse pulse-position modulation and return to zero modulation (QAM-MPPM-RZ). In this scheme, the two orthogonal polarization states enable simultaneous transmission of four data flows, which can provide different services for users according to the data rate requirement. To generate hybrid QAM-MPPM-RZ mm-wave signal, the QAM mm-wave signal is directly modulated by MPPM-RZ signal without using digital signal processing (DSP) devices, which reduces the overhead of the encoding process. Then, the generated QAM-MPPM-RZ mm-wave signal is transmitted in PDM microwave photonic link based on SSB modulation. The sparsity characteristic of QAM-MPPM-RZ not only improves the power efficiency, but also decreases the degradation caused by the fiber chromatic dispersion. The simulation results show that, under the constraint of the same transmitted data rate, the PDM microwave photonic link with 50 GHz QAM-MPPM-RZ mm-wave signal achieves much lower levels of bit-error rate than ordinary 32-QAM. In addition, the increase of laser linewidth brings no additional impact to the proposed scheme.
A shortcoming of the RZ-SHAW model (A hybrid version of Root Zone Water Quality Model and The Simultaneous Heat and Water Model) is that it cannot simulate the plastic mulching technology which is ...widely used in arid areas. Our objectives in this study were to develop RZ-SHAW to include a new plastic module, and to evaluate the model’s performance over three years of maize (Zea mays L.) production in China. A new plastic module was added to compute changes in the shortwave and longwave radiation transfer, turbulent heat and vapor transfer from the surface, and the energy and water balances in the system associated with a plastic mulch layer. The modified RZ-SHAW model can adequately simulate soil water (0.017 cm3 cm−3 ≤ RMSE ≤ 0.030 cm3 cm−3) and capture the evaporation reduction and transpiration increase under plastic mulch. The model overestimated the increased soil temperatures under plastic mulch (2.3 ℃ over the 100-cm profile) compared to the measured data (1.4 ℃). Overall, the revised RZ-SHAW model adequately simulated soil water and heat exchange under plastic mulch conditions. The modified RZ-SHAW model can be used as an effective decision tool for management optimization in plastic mulched cropland.
•A new plastic mulch module was developed for the RZ-SHAW model.•The revised model improved soil water and temperature simulation under plastic mulch.•The model captures evaporation reduction and transpiration increase for plastic mulch.
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