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- 摘要
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- 实验方案
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Ultra high transmission capacity based on optical first order soliton propagation systems
摘要： This study presents the first order optical soliton propagation systems for ultra-high transmission distance that reaches up to 20,000 Km with transmission data rates of 80 Gb/s and its corresponding maximum Q-factor and Soliton peak power. The simulation has been performed for the distance up to 20000 Km at the operating wavelength of 1300 and 1550 nm.
关键词： High data rates,Soliton propagation systems,First order soliton
更新于2025-09-23 15:23:52
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Rainbow schlieren-based direct visualization of thermal gradients around single vapor bubble during nucleate boiling phenomena of water
摘要： Real time non-intrusive diagnostics of thermal gradients around a single vapor bubble in isolated nucleate pool boiling with water as the working fluid have been presented. Direct visualization of transient evolution of temperature gradients in the vicinity of the heated substrate and around the single bubble as it undergoes various sub-processes has been performed using rainbow schlieren deflectometry. Boiling experiments have been conducted under saturated conditions. Results have been presented in the form of two-dimensional rainbow schlieren images wherein the degree of color re-distribution gives a direct measure of the strength of thermal gradients. Through the real time experimental images, various sub-processes/phenomena associated with boiling heat transfer such as development of superheat layer in the vicinity of the heated substrate, inception and further growth of the vapor bubble followed by scavenging of the superheat layer as the vapor bubble departs into the bulk fluid have been discussed. The profiles of hue distribution near the triple contact line brought out the presence of near stagnant fluid zone in which the heat transfer phenomenon was seen to be primarily diffusion-dominated. Beyond this narrow region, significant bulk fluid movement was observed on the basis of the spatial distributions of hue values recorded in the form of real time schlieren images. The experiments further revealed an instantaneous localized bending of the superheat layer as the bubble leaves the heater surface and subsequent shedding of the wake vortices from the edges of the departing bubble as it moves upwards in the bulk fluid.
关键词： Whole field temperature distribution,Heat transfer rates,Nucleate pool boiling,Rainbow schlieren deflectometry
更新于2025-09-23 15:22:29
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A radiative transfer module for calculating photolysis rates and solar heating in climate models: Solar-J v7.5
摘要： Solar-J is a comprehensive radiative transfer model for the solar spectrum that addresses the needs of both solar heating and photochemistry in Earth system models. Solar-J is a spectral extension of Cloud-J, a standard in many chemical models that calculates photolysis rates in the 0.18–0.8 μm region. The Cloud-J core consists of an eight-stream scattering, plane-parallel radiative transfer solver with corrections for sphericity. Cloud-J uses cloud quadrature to accurately average over correlated cloud layers. It uses the scattering phase function of aerosols and clouds expanded to eighth order and thus avoids isotropic-equivalent approximations prevalent in most solar heating codes. The spectral extension from 0.8 to 12 μm enables calculation of both scattered and absorbed sunlight and thus aerosol direct radiative effects and heating rates throughout the Earth’s atmosphere. The Solar-J extension adopts the correlated-k gas absorption bins, primarily water vapor, from the shortwave Rapid Radiative Transfer Model for general circulation model (GCM) applications (RRTMG-SW). Solar-J successfully matches RRTMG-SW’s tropospheric heating profile in a clear-sky, aerosol-free, tropical atmosphere. We compare both codes in cloudy atmospheres with a liquid-water stratus cloud and an ice-crystal cirrus cloud. For the stratus cloud, both models use the same physical properties, and we find a systematic low bias of about 3 % in planetary albedo across all solar zenith angles caused by RRTMG-SW’s two-stream scattering. Discrepancies with the cirrus cloud using any of RRTMG-SW’s three different parameterizations are as large as about 20–40 % depending on the solar zenith angles and occur throughout the atmosphere. Effectively, Solar-J has combined the best components of RRTMG-SW and Cloud-J to build a high-fidelity module for the scattering and absorption of sunlight in the Earth’s atmosphere, for which the three major components – wavelength integration, scattering, and averaging over cloud fields – all have comparably small errors. More accurate solutions with Solar-J come with increased computational costs, about 5 times that of RRTMG-SW for a single atmosphere. There are options for reduced costs or computational acceleration that would bring costs down while maintaining improved fidelity and balanced errors.
关键词： solar heating,clouds,Cloud-J,climate models,radiative transfer,photolysis rates,scattering,aerosols,RRTMG-SW,Solar-J
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET) - Chennai (2018.3.22-2018.3.24)] 2018 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET) - Performance Analysis for Mixed Line Rates (MLR) WDM/DWDM Networks Under Various Modulation Techniques
摘要： In recent years, a rapid growth of new technologies requires communication systems to support higher bit rate and longer distance. The Optical network is one of the best optimal solutions which can satisfy the demand for high data rate. The performance of current optical networks depends on the traffic demands. To minimize the traffic mixed line rate (MLR) optical network is implemented. In a transparent MLR optical network, data transmission is done over different wavelength at different line rates within the same fiber. MLR optical networks with data rate 10/40/100 Gb/s over different wavelength channels is a new networking paradigm. This paper considers various modulation techniques in order to achieve better bit error rates (BER). It also shows that modulation technique has a great role in improving the data rates and quality of transmission.
关键词： Wavelength division multiplexing/Dense wavelength division Multiplexing (WDM/DWDM),Bit error rate,Chromatic dispersion,Mixed line rates,Physical layer impairments,Amplifier spontaneous emission
更新于2025-09-23 15:22:29
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Nonradiative decay and absorption rates of quantum emitters embedded in metallic systems: Microscopic description and their determination from electronic transport
摘要： We investigate nonradiative decay and absorption rates of two-level quantum emitters embedded in a metal at low temperatures. We obtain the expressions for both nonradiative transition rates and identify a unique, experimentally accessible way to obtain both nonradiative transition rates via electronic transport in the host metallic system. Our findings not only provide a microscopic description of the nonradiative channels in metals, but they also allow one to identify, determine, and differentiate them from other decay channels, which is crucial to the understanding and controlling of the light-matter interactions at the nanoscale.
关键词： nonradiative decay,metallic systems,quantum emitters,electronic transport,absorption rates
更新于2025-09-23 15:21:21
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[IEEE 2019 7th International Renewable and Sustainable Energy Conference (IRSEC) - Agadir, Morocco (2019.11.27-2019.11.30)] 2019 7th International Renewable and Sustainable Energy Conference (IRSEC) - Photovoltaic Dust Soiling Statistical Representation in Doha, Qatar
摘要： Qatar’s and the Gulf region’s photovoltaic (PV) energy potential is very high. Still, there are tradeoffs under such tropical arid climate, particularly regarding dust soiling losses during the long dry season. In-field performance analyses of PVs under varying soiling states enable the quantification of dust soiling losses. Such estimate of the soiling losses is done a posteriori, using temperature-corrected performance ratios. In the current paper, we study how exceptional events such as sandstorms and rainfalls are identified using statistical analyses of the soiling losses rates. The aim is to generate sets of synthetic years describing the regular dust soiling rates, as well as the exceptionally observed meteorological events. The proposed sets of yearlong synthetic soiling conditions have average statistical representativeness identical to our ongoing in-field experimental measurements. This especially allows economic assessments such as the optimization of dust cleaning scenarios of PV projects.
关键词： Photovoltaics dust soiling,Sandstorms,Statistics,Soiling loss rates,Rainfalls
更新于2025-09-23 15:21:01
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Resolving fine spectral features in lattice vibrational modes using femtosecond coherent spectroscopy
摘要： We show resolution of fine spectral features within several Raman active vibrational modes in potassium titanyl phosphate (KTP) crystal. Measurements are performed using a femtosecond time-domain coherent anti-Stokes Raman scattering spectroscopy technique that is capable of delivering equivalent spectral resolution of 0.1 cm?1. The Raman spectra retrieved from our measurements show several spectral components corresponding to vibrations of different symmetry with distinctly different damping rates. In particular, linewidths for unassigned optical phonon mode triplet centered at around 820 cm?1 are found to be 7.5±0.2 cm?1, 9.1±0.3 cm?1, and 11.2±0.3 cm?1. Results of our experiments will ultimately help to design an all-solid-state source for sub-optical-wavelength waveform generation that is based on stimulated Raman scattering.
关键词： damping rates,potassium titanyl phosphate,Raman active vibrational modes,femtosecond coherent spectroscopy,spectral resolution
更新于2025-09-23 15:21:01
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Handbook of Exoplanets || Occurrence Rates from Direct Imaging Surveys
摘要： The occurrence rate of young giant planets from direct imaging surveys is a fundamental tracer of the efficiency with which planets form and migrate at wide orbital distances. These measurements have progressively converged to a value of about 1% for the most massive planets (≥5–13 MJup) averaged over all stellar masses at separations spanning a few tens to a few hundreds of AU. The subtler statistical properties of this population are beginning to emerge with ever-increasing sample sizes: there is tentative evidence that planets on wide orbits are more frequent around stars that possess debris disks; brown dwarf companions exist at comparable (or perhaps slightly higher) rates as their counterparts in the planetary-mass regime; and the substellar companion mass function appears to be smooth and may extend down to the opacity limit for fragmentation. Within a few years, the conclusion of second-generation direct imaging surveys will enable more definitive interpretations with the ultimate goal of identifying the dominant origin of this population and uncovering its relationship to planets at smaller separations.
关键词： giant planets,brown dwarfs,debris disks,direct imaging,occurrence rates
更新于2025-09-23 15:21:01
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Transparent Electrode and Buffer Layer Combination for Reducing Carrier Recombination and Optical Loss Realizing over a 22%-Efficient Cd-Free Alkaline-Treated Cu(In,Ga)(S,Se) <sub/>2</sub> Solar Cell by the All-Dry Process
摘要： Structures of (K or Cs) alkaline-treated Cu(In,Ga)(S,Se)2 (CIGSSe) solar cells are developed, and their carrier recombination rates are scrutinized. It is determined that short-circuit current density (JSC) is enhanced (decreased optical loss), when ZnS(O,OH), (Cd,Zn)S, and Zn0.8Mg0.2O buffers with large band-gap energy (Eg) are applied as replacement of CdS buffer. The JSC is further increased, more reducing the optical loss, when Zn0.9Mg0.1O:B is used as transparent conductive oxide (TCO) with larger Eg and lower free carrier absorption than those of ZnO:Al. Furthermore, all carrier recombination rates throughout the devices with K or Cs treatment, especially at buffer/absorber interface and in quasi neutral region, are reduced, thereby reducing open-circuit voltage deficit (VOC,def), well consistent with the simulated ones. The carrier recombination rate at the buffer/absorber interface is further decreased, when the CdS and (Cd,Zn)S buffers, deposited by chemical bath deposition, are applied, leading to the more reduction of the VOC,def and the high conversion efficiency (η) of about 21%. Under the trade-off between VOC,def and optical loss, the highest η of 22.6% is attained with the lowest power loss (or the highest VOC × JSC) in the Cs-treated Cd-free CIGSSe solar cell with an optimized structure of glass/Mo/CIGSSe/Zn0.8Mg0.2O/Zn0.9Mg0.1O:B, fabricated by all-dry process, where the Zn0.8Mg0.2O buffer is prepared by the sputtering method. This occurs because the JSC is the highest attributable to the larger Eg of Zn0.8Mg0.2O buffer than those of the CdS and (Cd,Zn)S.
关键词： Zn1-xMgxO,Zn1-xMgxO:Al,Cu(In,Ga)(S,Se)2 thin-film solar cell,carrier recombination rates,Zn1-xMgxO:B,(Cd,Zn)S
更新于2025-09-23 15:19:57
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[IEEE 2019 International Conference on Electrical, Communication, and Computer Engineering (ICECCE) - Swat, Pakistan (2019.7.24-2019.7.25)] 2019 International Conference on Electrical, Communication, and Computer Engineering (ICECCE) - Modeling and Analysis of Novel Tandem Solar Cells
摘要： While relay-based cooperative networks (widely known in the literature as cooperative communication), where relays only forward signals from the sources to the destination, have been extensively researched, fully cooperative systems have not been thoroughly examined. Unlike relay networks, in a fully cooperative network, each node acts as both a source node sending its own data and a relay forwarding its partner’s data to the destination. Mutual cooperation between neighboring nodes is believed to improve the overall system error performance, especially when space-time codes are incorporated. However, a comprehensive performance analysis of space-time-coded fully cooperative communication from all three perspectives, namely error performance, outage probability, and energy efficiency, is still missing. Answers to the commonly asked questions of whether, in what conditions, and to what extent the space-time-coded fully cooperative communication is better than direct transmission are still unknown. Motivated by this fact and inspired by the increasing popularity of healthcare applications in wireless body area networks (WBANs), this paper derives for the first time a comprehensive performance analysis of a decode-and-forward space-time coded fully cooperative communication network in Rayleigh and Rician fading channels in either identically or non-identically distributed fading scenario. Numerical analysis of error performance, outage probability, and energy efficiency, validated by simulations, show that fully cooperative communication is better than direct transmission from all three aspects in many cases, especially at a low-power and low signal-to-noise ratio regime, which is a typical working condition in WBANs.
关键词： symbol error rates,energy efficiency,MIMO,space-time codes,Rician,decode-and-forward,outage probability,wireless body area networks,Cooperative communication,Rayleigh
更新于2025-09-23 15:19:57