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[ACM Press the 2017 Symposium - Santa Clara, California (2017.09.24-2017.09.27)] Proceedings of the 2017 Symposium on Cloud Computing - SoCC '17 - Job scheduling for data-parallel frameworks with hybrid electrical/optical datacenter networks
摘要： In spite of many advantages of hybrid electrical/optical datacenter networks (Hybrid-DCN), current job schedulers for data-parallel frameworks are not suitable for Hybrid-DCN, since the schedulers do not aggregate data traffic to facilitate using optical circuit switch (OCS). We propose SchedOCS, a job scheduler for data-parallel frameworks in Hybrid-DCN that aims to take full advantage of the OCS to improve the job performance.
关键词： Optical circuit switch,parallelism,traffic aggregation
更新于2025-09-23 15:21:21
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A new fluorescence probe based on diarylethene with a benzothiazine unit for selective detection of Cd2+
摘要： A novel photochromic diarylethene derivative containing a benzothiazine unit has been synthesized. Its photochromism and fluorescent selectivity to metal ions were studied in detail in methanol solution. Under the stimulation of Cd2+ ions, the derivative showed a significant fluorescence enhancement and obvious red shift, accompanied by the fluorescent color changed from dark purple to bright blue. The 1 : 1 stoichiometry between the derivative and Cd2+ was verified by titration experiments and high resolution mass spectrometry. In addition, a molecular logic circuit was designed with the emission intensity at 476 nm as output and the stimuli of Cd2+/EDTA and UV/vis as inputs.
关键词： Fluorescence probe,Cadmium,Logic circuit,Diarylethene
更新于2025-09-23 15:21:21
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AIP Conference Proceedings [Author(s) PROCEEDINGS OF THE INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2017 (ICCMSE-2017) - Thessaloniki, Greece (21–25 April 2017)] - Synthesis of energy-efficient FSMs implemented in PLD circuits
摘要： The paper presents an outline of a simple synthesis method of energy-efficient FSMs. The idea consists in using local clock gating to selectively block the clock signal, if no transition of a state of a memory element is required. The research was dedicated to logic circuits using Programmable Logic Devices as the implementation platform, but the conclusions can be applied to any synchronous circuit. The experimental section reports a comparison of three methods of implementing sequential circuits in PLDs with respect to clock distribution: the classical fully synchronous structure, the structure exploiting the Enable Clock inputs of memory elements, and the structure using clock gating. The results show that the approach based on clock gating is the most efficient one, and it leads to significant reduction of dynamic power consumed by the FSM.
关键词： PLD,synchronous circuit,finite state machine,low power circuits,power dissipation
更新于2025-09-23 15:21:21
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[IEEE 2018 Second International Conference on Computing Methodologies and Communication (ICCMC) - Erode (2018.2.15-2018.2.16)] 2018 Second International Conference on Computing Methodologies and Communication (ICCMC) - A STUDY ON MODELING AND SIMULATION OF PHOTOVOLTIC ARRAYS USING SINGLE DIODE METHOD
摘要： This paper presents a method of modeling and simulation of photovoltaic arrays. The main objective of this study is to achieve a circuit based simulation model of a photovoltaic cell and to scrutinize the results and compare them with respect to change in environmental parameters like irradiation and temperature. The proposed method of single diode model is implemented in MATLAB software based on the particular environmental condition. And on the basis of this study simulation results and ideal theoretical values are compared.
关键词： Renewable energy sources,MATLAB software,PV system,Single diode method,Open circuit current and short circuit voltage
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 7th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Raleigh, NC, USA (2019.10.29-2019.10.31)] 2019 IEEE 7th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Detailed Study of Breakdown Voltage and Critical Field in Wide Bandgap Semiconductors
摘要： We systematically study the analysis and simulation of ac-biased superconductor transition-edge sensor (TES) circuits. In these ac-biased circuits, the current and voltage of the TES experience large swings in both directions, and small-signal analysis around a dc steady state does not apply. To understand their electrical and thermal behavior, we rely on concepts and techniques from radio-frequency circuit simulation and introduce the periodic steady state and perform periodic ac analysis. We also construct TES device models based on a comprehensive two-fluid physical model and investigate the behavior of ac-biased TES circuits using advanced circuit simulators. By relating our findings to results for the analysis of dc-biased TES circuits, we give appropriate definitions for the current and temperature sensitivity of the TES in ac-biased circuits. Our work not only builds a rigorous foundation for theoretical analysis of ac-biased TES circuits but also introduces powerful simulation techniques valuable for their design and research.
关键词： Circuit analysis,computer simulation,superconducting devices
更新于2025-09-23 15:21:01
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Graphene disks for frequency control of terahertz waves in broadband applications
摘要： The terahertz (THz) gap lying between the microwave and optical parts of the electromagnetic spectrum has attracted immense attention due to its applications between radiofrequency (RF)/microwave and photonic systems. A structure consisting of a graphene sheet sandwiched between two graphene disks is introduced herein to control the reflection, absorption, and transmission of THz waves. The proposed metamaterial structures are designed analytically using transmission line theory. Also, the dimensions of the structure and the electrical gating of the graphene are optimized utilizing a genetic algorithm. The structure is simulated using two different methods: (1) a circuit model based on transmission line theory and (2) commercial full-wave software based on the finite element method, which are verified by the agreement between their results. Finally, the proposed method is used to design a THz filter and THz wave absorber, which are in great demand for application in modulators, sensors, detectors, and imaging systems.
关键词： Resonator,Circuit method,Coupling effect,Graphene,Genetic algorithm,Absorber design,Impedance matching
更新于2025-09-23 15:21:01
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Sputtered and selenized Sb2Se3 thin-film solar cells with open-circuit voltage exceeding 500??mV
摘要： Antimony selenide (Sb2Se3) is a potential absorber material for environment-friendly and cost-efficient photovoltaics and has achieved considerable progress in recent years. However, the severe open-circuit voltage (Voc) deficit ascribed to the interface and/or bulk defect states has become the main obstacle for further efficiency improvement. In this work, Sb2Se3 absorber layer was prepared by an effective combination reaction involving sputtered and selenized Sb precursor thin films. The self-assembled growth of Sb2Se3 thin films with large crystal grains, benign preferential orientation, and accurate chemical composition were successfully fulfilled under an appropriate thickness of Sb precursor and an optimized selenization scenario. Substrate structured Sb2Se3 thin-film solar cells, a champion device with a power-conversion efficiency of 6.84%, were fabricated. This device is comparable to state-of-the-art ones and represents the highest efficiency of sputtered Sb2Se3 solar cells. Importantly, the high Voc of 504 mV is closely related to the reduced deep level defect density for the Sb2Se3 absorber layer, the passivated interfacial defects for Sb2Se3/CdS heterojunction interface, and the additional heterojunction heat treatment-induced Cd and S inter-diffusion. This significantly improved Voc demonstrates remarkable potential to broaden its scope of applications for Sb2Se3 solar cells.
关键词： Open-circuit voltage,Selenization,Sb2Se3 solar Cell,Elemental inter-diffusion,Sputtering
更新于2025-09-23 15:21:01
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[IEEE 2020 IEEE 11th Latin American Symposium on Circuits & Systems (LASCAS) - San Jose, Costa Rica (2020.2.25-2020.2.28)] 2020 IEEE 11th Latin American Symposium on Circuits & Systems (LASCAS) - Advancing Uncooled Infrared Imagers Using An Open-Circuit Voltage Pixel
摘要： A topology leveraging a photodetector in the forward bias region generating an open-circuit voltage is proposed. Connecting the anode of the photodetector to the gate of a MOSFET device operating in the subthreshold region provides the basis for a new open-circuit voltage pixel (VocP). Theoretical analysis outlining the effective photodetector response and performance benefits is described. An integrated circuit (IC) with direct-injection pixels modified to support the VocP front-end and analog output readout fabricated in a CMOS 0.18 μm technology is also presented. The IC allows testing of mid-wave infrared (IR) photodiodes operating in both the photocurrent and VocP modes. The VocP pixel is compared to a traditional reverse bias current mode photodetector configuration. Simulation, modeling, and measurement show improved sensitivity and faster response time for the VocP over direct photocurrent detection.
关键词： model,ROIC,open-circuit voltage,readout,MWIR,Mid-wave,Voc
更新于2025-09-23 15:21:01
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Reduced Non-radiative Recombination Energy Loss Enabled Efficient Polymer Solar Cells via Tuning Alkyl Chain Positions on Pendent Benzene Units of Polymers
摘要： Non-radiative recombination energy loss (ΔE3) plays a key role in enhancing device efficiencies for polymer solar cells (PSCs). Up to now, there is no clear resolution for reducing ΔE3 via molecular design. Herein, we report two conjugated polymers, PBDB-P-p and PBDB-P-m, which are integrated from benzo[1,2-b:4,5-b′]dithiophene (BDT) with alkylthio chain substituted at para- or meta- position on pendent benzene and benzo[1,2-c:4,5-c′]dithiophene-4,8-dione (BDD). Two polymers have different temperature-dependent aggregation properties, but similar molecular energy levels. When BO-4Cl was used as acceptor to fabricate PSCs, the device of PBDB-P-p:BO-4Cl displayed a maximal power conversion efficiency (PCE) of 13.83%, while the best device of PBDB-P-m:BO-4Cl exhibited a higher PCE of 14.12%. The close JSCs and FFs in both PSCs are attributed to their formation of effective nanoscale phase-separation as confirmed by atomic force microscopy (AFM) measurements. We find that the PBDB-P-m-based device has one order of magnitude higher of electroluminescence quantum efficiency (EQEEL) than that in PBDB-P-p-based one, which could arise from the relatively weak aggregation in PBDB-P-m-based film. Thus, the PBDB-P-m-based device has a remarkably enhanced VOC of 0.86 V in contrast to 0.80 V in PBDB-P-p-based device. This study offers a feasible structural optimization way on the alkylthio side chain substitute position on the conjugated polymer to enhance VOC by reducing non-radiative recombination energy loss in resulting PSCs.
关键词： polymer solar cells,open-circuit voltage,non-radiative recombination energy loss,polymer donor,alkylthio substituted position
更新于2025-09-23 15:21:01
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Counter-intuitive junction temperature behavior in AlGaN-based deep-ultraviolet light-emitting diodes
摘要： The junction temperature, one of the major parameters that strongly affect the performance of light-emitting diodes (LEDs), increases during operation because of the power dissipated as heat within an LED device. Therefore, LED devices with poor characteristics are expected to have higher junction temperatures for the same driving conditions. In this study, an observation contrary to this expectation is presented: a deep-ultraviolet LED device with superior electrical characteristics shows a higher junction temperature at the same input electrical power than a device with poor characteristics. A simple equivalent circuit comprising a diode, a series resistor, and shunt components is employed to elucidate this counter-intuitive observation by considering the possible heat sources inside the LED device. It is found that the junction temperature is mainly dominated by the power dissipated at the diode instead of the other possible heat sources including the Joule heating effect of the resistive components.
关键词： junction temperature,Joule heating,AlGaN-based deep-ultraviolet light-emitting diodes,power dissipation,equivalent circuit
更新于2025-09-23 15:21:01