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[IEEE 2018 OCEANS - MTS/IEEE Kobe Techno-Ocean (OTO) - Kobe, Japan (2018.5.28-2018.5.31)] 2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO) - A High Dynamic Range in Situ Flow Sensor
摘要： High dynamic range and high accuracy flow sensor is a highly desirable device in quantifying mixing in the atmosphere and the ocean, which is critical in our understanding of energy dissipation and flux studies. We discuss a design that utilizes only a single point sensor in different angles, based on our novel oriented temperature Fabry-Perot using interferometry approach. We report the sensitivity of a high-dynamic range sensor head orientation in such configuration. We discuss initial configuration, data collection, processing, analysis and calibration including sensor orientation for future deployment.
关键词： Fabry-Perot interferometer,flow meter,turbulence,kinetic energy dissipation,fiber optics
更新于2025-09-23 15:23:52
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Simple and ultrafast resonance frequency and dissipation shift measurements using a fixed frequency drive
摘要： A new method for determination of resonance frequency and dissipation of a mechanical oscillator is presented. Analytical expressions derived using the Butterworth-Van Dyke equivalent electrical circuit allow the determination of resonance frequency and dissipation directly from each impedance datapoint acquired at a fixed amplitude and frequency of drive, with no need for numerical fitting or measurement dead time unlike the conventional impedance or ring-down analysis methods. This enables an ultrahigh time resolution and superior noise performance with relatively simple instrumentation. Quantitative validations were carried out successfully against the impedance analysis method for inertial and viscous loading experiments on a 14.3 MHz quartz crystal resonator (QCR). Resonance frequency shifts associated with the transient processes of quick needle touches on a thiol self-assembled-monolayer functionalised QCR in liquid were measured with a time resolution of 112 μs, which is nearly two orders of magnitude better than the fastest reported quartz crystal microbalance. This simple and fast fixed frequency drive (FFD) based method for determination of resonance frequency and dissipation is potentially more easily multiplexable and implementable on a single silicon chip delivering economies of scale.
关键词： Quartz crystal microbalance,Dissipation shift,Realtime monitoring,Acoustic sensor,Resonance frequency shift,Time resolution of biomolecular process measurement
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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Continuous-wave operation of a 1.3 <i>??</i> m wavelength npn AlGaInAs/InP transistor laser up to 90 ?°C
摘要： A transistor laser (TL) is a device that operates at a high-speed with multiple functions such as output control with low wavelength shift and signal mixing. By adopting a high heat dissipation structure with a high-speed compatible wide electrode pad and thick Au plating in TLs, improvement of temperature performance in 1.3 μm wavelength npn AlGaInAs/InP TL was demonstrated. As a result, continuous-wave operation of a 1.3 μm TL up to 90 °C was achieved. The thermal resistance was estimated to be 25 K W?1, based on the spectrum behavior, which is at least four times lower than the previously observed value.
关键词： transistor laser,AlGaInAs/InP,continuous-wave operation,thermal resistance,high heat dissipation structure
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
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Infrared Cameras in Electronics Development
摘要： There has been a distinct trend in electronics development in the last few years: Packing density is increasing. Today, modern smartphones are much more powerful than they were only a few years ago, yet they are no bigger. The same applies to IT devices, automobile electronics, and consumer electronics. Accordingly, problems caused by heating must be looked out for with great care. Modern infrared measurement technology is an important aid in this regard.
关键词： electronics development,heat dissipation,Infrared cameras,semiconductor devices,temperature measurement,power loss
更新于2025-09-23 15:21:01
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Arrhenius Activation Energy Impact in Binary Chemically Reactive Flow of TiO2-Cu- H2O Hybrid Nanomaterial
摘要： Main motivation of the present research article is to investigate impact of Arrhenius activation energy in stagnation point flow of hybrid nanomaterial towards a stretched surface. Hybrid nanomaterial comprises of two or more types of nanomaterials along with continuous phase liquid. In this study two types of nanofluids are used namely titanium dioxide and copper. Nonlinear system is converted to ordinary system through appropriate transformation. For convergence series solutions, the obtained system is solved using homotopy analysis methods. Lorentz force impact is observed. Graphical results for different physical variables on the velocity, concentration, induced magnetic field and temperature for ???? ? ??2?? and ??????2 ? ????/??2?? are discussed. The physical aspects of skin friction and Sherwood and Nusselt numbers are discussed by tabulated values.
关键词： viscous dissipation,lorentz force,hybrid nanofluid,activation energy,chemical reaction,nonlinear radiation
更新于2025-09-23 15:21:01
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Manipulating and probing the distribution of excess electrons in an electrically-isolated self-assembled molecular structure
摘要： Exploiting single electrical charges and their mutual interactions for computation has been proposed as a concept for future nanoelectronics. Controlling and probing charge transfer in electrically isolated atomic-scale structures are fundamental to push its experimental realization. Here, we controllably inject individual excess electrons and study their distribution in a self-assembled structure supported on a non-conductive substrate. The self-assembly ensures structural order down to the atomic scale. Depending on the charge state of the molecular assembly, intermolecular electron hopping and specific electron distributions have been resolved by atomic force microscopy, clarifying the charge-transfer pathways in the tunnel-coupled structure. Exploiting the mutual charge interactions, control over specific charge distributions in the self-assembled structure has been achieved with single-molecule precision, paving the way towards the design of data processing platforms based on molecular nanostructures.
关键词： self-assembly,atomic force microscopy,dissipation,single electron charging
更新于2025-09-23 15:19:57
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Prominent Heat Dissipation in Perovskite Light-Emitting Diodes with Reduced Efficiency Droop for Silicon-Based Display
摘要： Solution-processed perovskite light-emitting diodes (LEDs) possess outstanding optoelectronic properties for potential solid-state display applications. However, poor device stability results in significant efficiency droop partly being ascribed to Joule heating when LEDs are operated at high current densities. Herein, we used monocrystal silicon (c-Si) as substrate and charge injection layer to alleviate the thermal affection in perovskite LED (PeLED). By incorporating silicon oxide (SiOx) and poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(4,4’-(N-(4-butylphenyl) (TFB) layer to tune the charge injection balance in c-Si-based device, a PeLED achieves an external quantum efficiency of 2.12% with a current efficiency of 6.06 cd A-1. Benefiting from excellent heat dissipation of c-Si, the PeLEDs display reduced efficiency droop and extended operational lifetime. Furthermore, both electroluminescent (EL) dynamic information display and static pattern displays of c-Si-based PeLED have been successfully demonstrated. These results reveal the feasibility of potential practical c-Si-based PeLEDs with reduced efficiency droop for EL display applications.
关键词： efficiency droop,silicon substrate,perovskite light-emitting diode,display application,heat dissipation
更新于2025-09-23 15:19:57
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Study on Nitrogen-Doped Graphene Ink and Its Effects on the Heat Dissipation for the LED Lamps
摘要： This study explored the application of nitrogen-doped graphene (NDG) ink to the coating of light-emitting diode (LED) lamps for the thermal management. Unlike the general solutions of graphene, the NDG ink used in this study was tuned with high electrical resistance and quietly suitable for the application of the LED lamp coating, which prevented the short circuit problem; besides, the NDG ink also provided a high heat dissipation effect to improve the performance of the LED lamp. The investigation of adhesion and resistance for the NDG ink were conducted by the cross-cut test and the four-point probe resistance measurement, respectively. Three types of LED lamps including the original lamp, fin-removed lamp, and NDG-ink coated (NGC) lamp were tested for the actual operating temperature distribution by K-type thermal couples and for the lumens by the integrating sphere. The results showed that the heat dissipation of the NGC lamp was better than that of the original lamp. In addition, the inspections for the properties of NDG powder were also performed by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and Raman spectroscopy. According to the inspectional results, the NDG powder had a percentage of nitrogen of about 3.8% by XPS, a surface roughness Rq of 0.9 nm by AFM, and over ten layers by Raman analysis. It showed that the NDG powder in this study belonged to the type of multi-layer graphene.
关键词： integrating sphere,heat dissipation,nitrogen-doped graphene,LED
更新于2025-09-23 15:19:57