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.
We demonstrate a four-to-one 100-GS/s time interleaver realized in a 55-nm BiCMOS technology. The interleaver comprises two stages of two-to-one sub-interleavers. Each sub-interleaver is implemented ...using a return-to-zero generation and summing architecture. This sub-interleaver architecture ensures lower clock feedthrough and contains an inherent feed-forward equalizer. Effective number of bits (ENOB) measurements have been performed revealing the interleaver's ENOB of 4.9 at 3 GHz. In addition, the transfer function is measured to show the capabilities of the inherent feed-forward equalizer of the sub-interleavers. The measured analog output bandwidth of the four-to-one interleaver is 73 GHz. Finally, a 100-GBd PAM-4 (200 Gb/s) signal is generated by interleaving four 25-GBd PAM-4 streams while consuming 700 mW.
ABSTRACT
RZ Psc is a young Sun-like star with a bright and warm infrared excess that is occasionally dimmed significantly by circumstellar dust structures. Optical depth arguments suggest that the ...dimming events do not probe a typical sightline through the circumstellar dust, and are instead caused by structures that appear above an optically thick mid-plane. This system may therefore be similar to systems where an outer disc is shadowed by material closer to the star. Here, we report the discovery that RZ Psc hosts a $0.12\, \mathrm{ M}_\odot$ companion at a projected separation of 23 au. We conclude that the disc must orbit the primary star. While we do not detect orbital motion, comparison of the angle of linear polarization of the primary with the companion’s on-sky position angle provides circumstantial evidence that the companion and disc may not share the same orbital plane. Whether the companion severely disrupts the disc, truncates it, or has little effect at all will require further observations of both the companion and disc.
Discrepancies between competing optical and near-infrared (NIR) spectral typing systems for L dwarfs have motivated us to search for a classification scheme that ties the optical and NIR schemes ...together, and addresses complexities in the spectral morphology. We use new and extant optical and NIR spectra to compile a sample of 171 L dwarfs, including 27 low-gravity β and γ objects, with spectral coverage from 0.6-2.4 m. We present 155 new low-resolution NIR spectra and 19 new optical spectra. We utilize a method for analyzing NIR spectra that partially removes the broad-band spectral slope and reveals similarities in the absorption features between objects of the same optical spectral type. Using the optical spectra as an anchor, we generate near-infrared spectral average templates for L0-L8, L0-L4γ, and L0-L1β type dwarfs. These templates reveal that NIR spectral morphologies are correlated with the optical types. They also show the range of spectral morphologies spanned by each spectral type. We compare low-gravity and field-gravity templates to provide recommendations on the minimum required observations for credibly classifying low-gravity spectra using low-resolution NIR data. We use the templates to evaluate the existing NIR spectral standards and propose new ones where appropriate. Finally, we build on the work of Kirkpatrick et al. to provide a spectral typing method that is tied to the optical and can be used when only H or K band data are available. The methods we present here provide resolutions to several long-standing issues with classifying L dwarf spectra and could also be the foundation for a spectral classification scheme for cloudy exoplanets.
•We analytically solve the Lippmann-Schwinger equation for an spheroidal barrier;•We find solutions for different potential’s strengths.•The resonance condition is related to the zeros of a radial ...spheroidal function.•We generalize our result for the scattering by N spheroidal barriers.
We present exact solutions to the Lippmann-Schwinger equation for the scattering of a plane wave by an oblate spheroidal barrier modeled as a boundary-wall with coupling strength γ=γ(η,ϕ). We study analytically two representative potential strengths: (i) γ(η,ϕ)=γ0/ξ02+η2,that is a coupling strength which compensates the variation of the spheroid surface element; and (ii) a constant potential γ(η,ϕ)=γ0. In the first case, we present a condition that must be satisfied in order to a resonance effect to take place inside the barrier. We use this result as a basis to obtain the solution for the scattering of a plane wave by Nspheroidal barriers.
Free space optical (FSO) communication has gained significant popularity in recent years due to large bandwidth, license‐free spectrum, high data rates, less power consumption, and low mass ...requirements. However, system performance strongly depends on atmospheric conditions and ambient noise. In this letter, the duobinary modulation technique is applied and the system performance is investigated in the presence of ambient noise. The system is evaluated on the basis of Q‐factor, eye diagram, input power, transmission distance, and bit error rate. A significant improvement is observed in the presence of noise while using duobinary modulation. This study exploits extensive simulations to investigate the performance of the system. All simulations are performed for a single link of FSO communication network having a data rate of 40 Gbps in the Optisystem simulator and ambient noise is created using LEDs. After the exhaustive set of simulations, a significant improvement in transmission length is observed. It is also observed that at low input power, doubinary modulation provides better results when compared with on‐off keying (OOK) format. Scintillation effect has also be observed for doubinary modulation and compared with OOK modulation format. It is concluded that doubinary modulation provides better results in the presence of low and moderate scintillation.
Recombination zone (RZ) confinement and charge balance are the most important factors for realizing the enhanced efficiency in phosphorescent organic light emitting devices (Ph-OLEDs). Here, we ...demonstrated the RZ movement and improved Ph-OLED efficiency by varying the electron transport layer 2,2′,2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) thickness. The thickness increment of TPBi not only control the electron transport on to the emission layer but also shifting the RZ towards cathode. The RZ movement in Ph-OLED with different thick TPBi is extracted from the exciplex peak generated at exciton blocking layer/emission layer (EML) interface. The optimized electron to hole ratio at EML have occurred with 40 nm TPBi in which the Ph-OLED exhibits superior current efficiency of 80 cd A−1. The Ph-OLED efficiency roll-off is also very low in 40 nm TPBi based devices. This efficiency roll-off and RZ shift were simply estimated by interface exciplex peak in electroluminescence intensity without extra sensing layers. Further, the electron only devices made with various TPBi thickness also demonstrated the possible changes in the electron transport and supports the RZ and charge balance tactics.
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