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[IEEE 2018 37th Chinese Control Conference (CCC) - Wuhan (2018.7.25-2018.7.27)] 2018 37th Chinese Control Conference (CCC) - Silicon Melt Liquid Level Detection Based on Improved Laser Trigonometry
摘要： In order to improve the robustness of laser triangulation to detect the liquid level of silicon melt, this paper ?rstly proposes a method of calculating the laser spot coordinates based on the voting mechanism. The vote is taken according to the coordinates of small laser spots, which are formed by the effect of liquid surface ?uctuation on the line laser in the liquid level measurement image. Secondly, the Kalman ?lter method is used to correct the liquid level measurement data and compensate the missing data. Then the linear conversion is performed to obtain the liquid level value. Finally, the experimental results show that this method can effectively improve the robustness of the liquid level measurement by the laser triangulation method, and avoid the generation of impulse noise. The introduction of the Kalman ?lter can accurately correct the level measurement data and compensate for missing data.
关键词： Single crystal furnace,Kalman ?lter,Coordinate calculation,Voting mechanism,Liquid level detection
更新于2025-09-16 10:30:52
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Mechanism of silver/glass interaction in the metallization of crystalline silicon solar cells
摘要： In order to reveal the interaction between solid substances (Ag powder and glass frit) during the metallization of crystalline silicon solar cells, the effect of glass frit on the Ag powder sintering and the mechanism of Ag colloid formation in glass phase were investigated. The results show that the Ag powder could grow into larger grains as mixed with a certain amount of glass frit, because the corrosion of Ag by glass melt enabled early start of Ag sintering. This makes the internal grain size and electric resistivity of sintered Ag lines to be closely related to the glass content in the silver paste. Subsequently, it was found that the formation of Ag colloid in glass phase is a physical process rather than a chemical transformation process. Taking Pb-B-Zn-Al composite oxide glasses for exemplification, a feasible strategy of raising the solubility of Ag in glass melt is proposed.
关键词： silver colloid formation,solid interaction mechanism,metallization,glass corrosion effect,silicon solar cells
更新于2025-09-16 10:30:52
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Monotectic growth evolution and raman scattering of self-assembled ZnO hierarchical micro-nanostructures
摘要： The self-assembled hierarchical micro-nanostructures with geometric complexity and/or constituent diversity are becoming a promising class of candidates for the next generation nanotechnology. Different from conventional vapor-liquid-solid (VLS) eutectic liquid droplets for one-dimensional (1D) nanowires, the Zn-Bi VLS monotectic liquid droplets are employed to build 1D, 2D and 3D ZnO into 3D hierarchical micro-nanostructures. As-obtained micro-nanostructures are well de?ned self-assembly and have not yet been observed in the conventional eutectic alloys. The synergy of monotectic droplets and nonthermal equilibrium is responsible for the evolution of ZnO hierarchical micro-nanostructures. Raman spectra show that E2H and E1L modes are shifted slightly towards the high-wavenumber side by an amount of 3.7 and 2 cm?1 as compared with undoped ZnO nanowires and an additional peak at 519.5 cm?1 is associated with Bi38OZn60. The results manifest that 3D ZnO micro-nanoarchitectures possess a bulk phonon structure. The monotectic liquid droplet route presented in this paper may offer a new opportunity to the fabrication of hierarchical nanostructures for realistic technology platforms with multifunctional coupling and interplay.
关键词： nanowires,growth mechanism,nanofabrications,nanostructures,Raman scattering
更新于2025-09-16 10:30:52
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[IEEE 2019 Big Data, Knowledge and Control Systems Engineering (BdKCSE) - Sofia, Bulgaria (2019.11.21-2019.11.22)] 2019 Big Data, Knowledge and Control Systems Engineering (BdKCSE) - Thermoelectric Cooling Driver for Laser Projection Systems
摘要： Recent investigations have revealed the susceptibility of phasor measurement units (PMUs) to the time synchronization attack by spoofing its global positioning system (GPS). This paper proposes a cross-layer detection mechanism to fight against simultaneous attacks toward multiple PMUs. In the physical layer, we propose a GPS carrier-to-noise ratio (C/No) based spoofing detection technique. We apply the patch-monopole hybrid antenna to two GPS receivers and compute the difference between the standard deviation of each receiver’s C/No. The priori probability of spoofing is calculated from the distributions of the difference. A counter is embedded in the physical layer to identify the most suspicious PMU. In the upper layer, the spoofing attack is considered similarly to the bad data injection toward the power system. A trustworthiness evaluation, which is based on both the physical layer information and power grid measurements, is applied to identify the PMU being attacked. An experiment has been carried to validate the proposed algorithm.
关键词： Cross-layer mechanism,multiple attacks detection,phasor measurement units (PMU),global positioning system (GPS) spoofing
更新于2025-09-16 10:30:52
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Efficient blue-white color luminescence with near-ultraviolet excitation in Dy3+/Tm3+:Na3Gd(PO4)2 nanophosphor for white LEDs
摘要： The Dy3t/Tm3t ions co-activated Na3Gd(PO4)2 phosphors were synthesized by the citrate-gel based combustion technique. The structural properties of as-synthesized phosphors were studied through X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The influence of Tm3t concentration on the fluorescence properties of Na3Gd(PO4)2:Dy3t phosphors were systematically investigated under near-UV light irradiation of 359 and 352 nm. The energy transfer efficiency (ηET) of as-prepared phosphors increases gradually from 17 to 42%, and the critical distance (Rc) between Dy3t and Tm3t ions is calculated to be 4.76 ?. For better understanding the energy transfer mechanism (ET:Dy3t →Tm3t), the decay curves were utilized on the basis of Dexter’s energy transfer formula and Reisfeld’s approximation. More importantly, the obtained CIE color coordinates of Na3Gd(PO4)2:Dy3t/Tm3t phosphors located at blue-white region under near-UV light irradiation. The results demonstrate the promising application of Na3Gd(PO4)2:Dy3t/Tm3t phosphor for near-UV white LEDs.
关键词： Citrate-gel combustion technique,Decay times-Energy transfer mechanism,Photoluminescence,White-light,Dy3t/Tm3t
更新于2025-09-16 10:30:52
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Preparation and growth mechanism of CdS quantum dots in octadecene/glycerol two-phase systems
摘要： Two-phase synthesis is an advantageous alternative to the traditional synthetic method, due to its less toxicity, controllable, mild synthetic conditions and easy large-scale synthesis. However, meeting novel synthesis, the conventional trial-and-error approach could not provide a clear understanding. We herein report synthesis and mechanism investigation of CdS quantum dots in octadecene/glycerol two-phase system. The effects of different reaction parameters and conditions including reaction temperature, reaction time, reactant concentrations, and synthesis routes (one-step and two-step approach) on both nucleation and particle growth were investigated. It was found that the synthesis course was a growth dominated process depending on both CdS(monomer) and CdS (nuclei), and controlled by the interface of ODE/glycerol. The present work provided a new and clear understanding about two-phase system synthesis on semiconductor quantum dots, noble metal nanocrystals and some alloy nanomaterials.
关键词： Octadecene/glycerol two-phase systems,Growth mechanism,CdS quantum dots,One-step synthesis
更新于2025-09-16 10:30:52
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Water-soluble ZnO quantum dots modified by (3-aminopropyl)triethoxysilane: The promising fluorescent probe for the selective detection of Cu2+ ion in drinking water
摘要： Copper, as an essential element in human body, can have adverse impact on environment and healthy individuals if it is excessive. So it is necessary to establish a rapid and effective method for detecting Cu2+. In this work, we describe a method for determination of Cu2+ based on water-soluble ZnO quantum dots (QDs) modified with (3-aminopropyl)triethoxysilane (APTEs). The ZnO QDs functionalized with APTEs (NH2-ZnO QDs) synthesized by a simple sol-gel method and displayed strong yellow-green fluorescence with a peak at 535 nm under 350 nm excitation. High-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, luminescence, and UV-visible absorption spectroscopy were used to characterize the NH2-ZnO QDs. In addition, the emission from NH2-ZnO QDs was selectively quenched upon addition of Cu2+. Therefore, this finding was used to design a fluorescent probe based on NH2-ZnO QDs to detect Cu2+ in water solution, and the linear relationships were 2-20 nM and 1-100 μM respectively, with detection limit for Cu2+ at 1.72 nM (on the basis of 3σ/slope criterion). This fluorescent probe had also been applied in real water sample to testify its availability in drinking water. Furthermore, the quenching mechanism was studied by measurements of UV-visible absorption spectra and fluorescent lifetime of ZnO QDs, which may be attributed to the aggregation induced by Cu2+ and the dynamic quenching existing energy transfer between QDs and Cu2+.
关键词： Drinking water,Water-soluble,Fluorescent probe,Cu2+ detection,ZnO QDs,Quenching mechanism
更新于2025-09-16 10:30:52
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Laser-Induced Ignition and Combustion of Individual Aluminum Particles Below 10 ??m by Microscopic High-Speed Cinematography
摘要： Metal aluminum has been widely used as an ingredient in propellant, gunpowder and thermite, but there is less understanding of the combustion mechanism of aluminum particles from submicron to several microns in diameter. This paper proposes to experimentally investigate the ignition and combustion characteristics of individual aluminum particles below 10 μm. A specific in situ diagnostic experimental apparatus was first designed for directly observing the ignition and combustion behaviors of individual aluminum particles, with a submicrometer spatial resolution and a temporal resolution of tens of microseconds. Direct observation through microscopic high-speed cinematography demonstrated that, when heated by a continuous laser, individual aluminum particles thermally expanded, followed by shell rupture; the molten aluminum core overflowed and evaporated, leading to ignition and combustion. Further results showed that, when the laser power densities were gradually increased (5.88, 7.56 and 8.81 × 105 W/cm2), the durations of thermal expansion, melting and evaporation were shortened. The required time for the aluminum particles to expand to 150% of their initial diameter was shortened (34 s, 0.34 s and 0.0125 s, respectively). This study will be beneficial to further extend the investigation of other individual metal particles and reveal their combustion mechanism by direct observation.
关键词： combustion mechanism,microscopic high-speed cinematography,individual aluminum,laser ignition,submicron particle
更新于2025-09-16 10:30:52
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The impact of laser energy, bias and irradiation positions on single event transients of InP HBT
摘要： The mechanism of single event transients in indium phosphide heterojunction bipolar transistors are studied with different laser energy, collector and irradiation positions based on a pulsed laser experiment. The area of the depletion region neutralized by the laser track determines the area of the funnel region, and affects the total charges collected by collector QTotal. The total charge collection consists of the charge collected in the depletion region, the charges collected in funnel region, and the diffusion charges. The larger the area of the neutralized depletion region, the larger the area of the funnel region, thus, the more electron–hole pairs would be collected. The influence of laser energy, collector bias and irradiation positions on total charge collection is studied and discussed in detail.
关键词： transient current,single event transient,charge collection mechanism,pulsed laser
更新于2025-09-16 10:30:52
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Quantum Transmission Line Modelling and Experimental Investigation of the Output Characteristics of a Terahertz Quantum Cascade Laser
摘要： Magnetorheological (MR) fluid is a widely used smart material due to its outstanding properties. This paper presents the design, development, modeling, and prototype testing of a self-energizing and self-powered MR brake-by-wire system, whose aforementioned capabilities are enabled by brake energy harvesting. The system is composed mainly of a typical T-shaped drum-type MR brake and a wedge mechanism for self-energizing purpose. Into the system, we also install a generator that harvests regenerative energy during braking, thereby creating a self-power capability that cannot be found in common vehicular brake-by-wire systems. Brake torque analysis is conducted, and the braking process is simulated in a MATLAB/Simulink environment. Finite element analysis of the magnetic field, temperature field, and mechanical strength of critical components is carried out. The simulation results are used to optimize design parameters and material selection. Finally, prototypes and a corresponding test rig are established. The experimental results show that only about 30 W of power is required to generate a 315 N·m brake torque and that the regenerative power produced by the generator can be used for braking, thus fulfilling the self-power requirement. The investigation of different wedge angles indicates that considerable self-energizing occurs under a small wedge angle. The findings demonstrate that the brake actuator, which has a relatively small volume, can significantly enlarge brake torque while harvesting brake energy. This feature enables the promising application of MR fluids in automotive brake systems.
关键词： wedge mechanism,energy harvesting,magnetorheological (MR),Brake-by-wire system,self-powered capability
更新于2025-09-16 10:30:52