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The Impact of Peltier Effect on the Temperature Field During Spark Plasma Sintering of Thermoelectric Materials
摘要： We report about the modelling of spark plasma sintering of a line of thermoelectric materials. A significant difference of sintering temperature DTs from 15 K to 110 K was found in the samples studied. The Peltier effect on the graphite-thermoelectric interfaces results in such temperature difference. The rise of sintering temperature leads to the DTs increase. DTs in the vertical direction is 2–3 times higher than in the radial one. Electric insulation modelled in the horizontal graphite–thermoelectric interfaces reduced DTs in all the types of numerically studied samples by 59–92%.
关键词： spark plasma sintering,FEM,SPS,Thermoelectrics,finite elements simulation
更新于2025-09-23 15:22:29
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Largea??Scale Plasmonic Hybrid Framework with Builta??In Nanohole Array as Multifunctional Optical Sensing Platforms
摘要： Light coupling with patterned subwavelength hole arrays induces enhanced transmission supported by the strong surface plasmon mode. In this work, a nanostructured plasmonic framework with vertically built-in nanohole arrays at deep-subwavelength scale (6 nm) is demonstrated using a two-step fabrication method. The nanohole arrays are formed first by the growth of a high-quality two-phase (i.e., Au–TiN) vertically aligned nanocomposite template, followed by selective wet-etching of the metal (Au). Such a plasmonic nanohole film owns high epitaxial quality with large surface coverage and the structure can be tailored as either fully etched or half-way etched nanoholes via careful control of the etching process. The chemically inert and plasmonic TiN plays a role in maintaining sharp hole boundary and preventing lattice distortion. Optical properties such as enhanced transmittance and anisotropic dielectric function in the visible regime are demonstrated. Numerical simulation suggests an extended surface plasmon mode and strong field enhancement at the hole edges. Two demonstrations, including the enhanced and modulated photoluminescence by surface coupling with 2D perovskite nanoplates and the refractive index sensing by infiltrating immersion liquids, suggest the great potential of such plasmonic nanohole array for reusable surface plasmon-enhanced sensing applications.
关键词： modulated photoluminescence (PL),refractive index (RI) sensing,titanium nitride (TiN),surface plasmons (SPs),plasmonic nanoholes (NHs)
更新于2025-09-23 15:19:57
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In Situ Ion Exchange Synthesis of Cauliflower-like AgBr/Ag3PO4/Sulfonated Polystyrene Sphere Heterojunction Photocatalyst With Enhanced Photocatalytic Activity
摘要： The cauliflower-like AgBr/Ag3PO4/sulfonated polystyrene sphere (SPS) heterojunction photocatalyst was prepared using wastewater containing silver ion and SPS as raw materials via in situ ion change method. The AgBr/Ag3PO4/SPS photocatalyst was characterized by field emission scanning electron microscopy, X-ray diffraction and UV–Vis diffuse reflectance spectra (UV–Vis DRS). The results showed that AgBr nanoparticles and Ag3PO4 nanoparticles are highly dispersed on the surface of sulfonated polystyrene. And the heterogeneous junction structures are also formed between AgBr and Ag3PO4, which is benefit for the separation of photogenerated electrons and holes. Hence, the AgBr/Ag3PO4/SPS photocatalyst had an excellent activity for photocatalytic degradation of rhodamine B (RhB) in water under visible light irradiation. The cyclic test results showed that the AgBr/Ag3PO4/SPS photocatalyst also had a good stability.
关键词： Semiconductor,Functional material,Polymeric composite,AgBr/Ag3PO4/SPS
更新于2025-09-19 17:15:36
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Enhancing THz Emission using a Shallow-Bounce Configuration
摘要： THz radiation promises to revolutionise applications in fields from security and counter terrorism, to medicine and agriculture. In the drive to develop robust, powerful and frequency-tunable THz laser sources, systems based on the stimulated polariton scattering (SPS) process, derived from solid state architectures, are arguably at the forefront. Within the realm of THz-SPS lasers, there are significant opportunities to enhance the performance of these systems, through careful consideration of the system architecture. It is well known that SPS-active crystals are inherently highly absorbing in the THz frequency range. This presents a dilemma in that while these crystals are capable of optically generating THz radiation, they are also the greatest cause of THz loss within these systems. This has led to system architectures/designs such as the surface-emitting configuration, which place the THz generation region as close to the emitting surface as possible. While this design has proven effective, it is but one consideration in maximising the possible THz power emitted from these systems. Of great relevance is the overall generation volume, its proximity to the emitting surface, and how this evolves with THz frequency tuning. Here, we report both computational modelling and experimental results contrasting the use of a new, novel, shallow-bounce architecture, in comparison to conventional linear and surface-emitting designs; the architecture of each is shown in Fig. 1. The shallow bounce system is shown schematically in Fig. 2. The system comprises a diode-end-pumped 0.3 at. % Nd:YVO4 laser crystal generating a fundamental field at 1342 nm. A flat end-mirror (M1), an x-cut 5 at. % MgO:LiNbO3 SPS crystal (HC Photonics Corp.) and a concave high reflectivity (HR) mirror (M2, radius of curvature (ROC) = 1000 mm) defined the ends of the fundamental resonator. The MgO:LiNbO3 crystal had dimensions of 5×5×20 mm3, and was AR coated on both end surfaces (R < 0.2 % at 1340 – 1380 nm at normal incidence). The system was Q-switched to achieve pulsed operation at a repetition rate of 5 kHz. A separate pair of HR mirrors (M3 and M4, ROC = 1000 mm; R = 99.9 % from 1340 – 1380 nm) were used to construct a 95 mm-long resonator which oscillated and bounced the Stokes field at the same TIR surface position as the fundamental field. Two high-resistivity Si-prisms with angles of 33°/33°/114° (dimensions 6×6×10 mm3) were placed in close proximity to the Teflon-coated polished x-z surface of the MgO:LiNbO3 crystal. These prisms extracted two THz beams at angles of ~ ± 30°relative to the TIR surface. The bounce angle of the fundamental field is 84.5 o (to the crystal normal), in comparison to 65 o which is typical in surface-emitting configurations. The shallow-bounce system generated dual-beam THz emission (with similar output powers and beam profiles) with a total, maximum average power of 67.5 (cid:541)(cid:58) for an incident CW pump power of 15.1 W. Notably, the frequency-tuning range was broad, covering the range 1.05 – 2.89 THz. High emission is maintained throughout this tuning range, especially in comparison to that achieved from linear and surface-emitting geometries, the details of which will be elucidated and discussed in this paper.
关键词： stimulated polariton scattering,THz-SPS lasers,shallow-bounce architecture,THz radiation,SPS
更新于2025-09-12 10:27:22
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Impact of silver nanogratings for enhanced light absorption in plasmonic based photodetector
摘要： Recent era has witnessed a wide interest of researchers for the development of nano scale high speed photodetectors. Now days, optical communication systems demand these detectors with light enhancement along with high gain and bandwidth. Plasmonics based photodetectors with gold nanogratings are employed in literature for high responsivity and miniaturization. However, these devices need to be explored for other metals as gold being very costly. In this work, plasmonic based photodetector is designed with silver nanogratings and analyzed over varying shapes like rectangular, trapezoidal, ellipse and parabolic taper. Enhanced light absorption with quenching factor of 73.96% is achieved with rectangular grooves in near infrared region as compared to other shapes.
关键词： Surface plasmons (SPs),Absorption,Nano gratings,Enhancement,Plasmonic,Photo-detectors,Subwavelength aperture,Finite-difference,Time-domain (FDTD) simulation
更新于2025-09-12 10:27:22
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Effects of sintering conditions on the microstructure and mechanical properties of SiC prepared using powders recovered from kerf loss sludge
摘要： The effects of sintering conditions on the microstructure and mechanical properties of the sintered SiC prepared using the SiC powder recovered from the kerf loss sludge were investigated. The recovered SiC powders were consolidated by spark plasma sintering (SPS) and conventional sintering methods. The effects of sintering temperature, time and methods (SPS and conventional sintering) on the phase, grain size and density of SiC were systematically studied. The Vickers hardness of spark plasma-sintered (SPSed) samples was higher than that of conventional sintered samples due to small grain size. When holding time was increased from 10 to 30 min, the grain size and relative density of SPSed samples were also increased, which lead to the almost constant Vickers hardness by competing effects of grain size and relative density. When holding time was over 30 min, no appreciable change of the relative density and grain size were observed, which can lead to similar values of Vickers hardness. SPS process can be used to make SiC with high density and hardness at relatively low temperature compared with the conventional sintering process.
关键词： Recovered SiC,spark plasma sintering (SPS),sintering conditions,conventional sintering
更新于2025-09-10 09:29:36
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[IEEE 2018 Open Innovations (OI) - South Africa (2018.10.3-2018.10.5)] 2018 Open Innovations Conference (OI) - Phase Formation Between Iridium Thin Films and Zirconium Carbide Prepared by Spark Plasma Sintering at Relatively Low Temperatures
摘要： Zirconium carbide (ZrC) samples were prepared by spark plasma sintering (SPS), at temperatures of 1700 °C, 1900 °C and 2100 °C at 50 MPa for 10 minutes. The phase and microstructure after the sintering process was investigated. The relative density of ZrC ceramic pellets formed at 1700 °C, 1900 °C and 2100 °C was measured and found to be 96.5 %, 98.9 % and 99.5 % respectively. The grain size of ZrC ceramic pellets was calculated and it was found to increase from 71.88 nm, 79.15 nm and 83.59 nm as the sintering temperature increased from 1700 oC, 1900 oC to 2100 oC respectively. The hardness of ZrC ceramic pellets was found to be 7.40 GPa, 17.00 GPa to 18.40 GPa at 1700 oC, 1900 oC to 2100 oC respectively. The preferred orientation at 1700 oC, 1900 oC and 2100 oC was the (200) plane. Iridium (Ir) thin films were deposited on ZrC ceramics by electron beam deposition method and annealed in vacuum at temperatures of 600 °C and 800 °C for 2h. The phase composition, solid-state reactions and surface morphology were investigated by grazing incidence x-ray diffraction (GIXRD), and scanning electron microscopy (SEM). XRD was used to identify the phases present in the as-deposited and annealed samples. XRD analysis showed that Ir2Zr was the initial phase formed at 600 °C. At temperature 800 °C, Ir reacted with the ZrC to form IrZr. The SEM images of as-sintered samples at 1700 oC, 1900 oC and 2100 oC showed that the ZrC surface was heterogeneous and uneven consisting of agglomerated granules with a few pores. The number of pores was observed to reduce with sintering temperature. After depositing Ir films on ZrC substrate, the structure of the Ir film followed that of the substrates. After annealing the Ir-ZrC samples at 600 oC and 800 oC, the further agglomeration of surface granules was observed.
关键词： morphology,interface reaction,Zirconium carbide,SPS,iridium
更新于2025-09-09 09:28:46
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Photostriction properties of PLZT (4/52/48) ceramics sintered by SPS
摘要： In this paper, the preparation and sintering process of Lanthanum-modi?ed lead zirconate titanate ceramics (PLZT 4/52/48) powders and ceramics were investigated. The PLZT powders were prepared by co-precipitation and sol-gel methods. It is con?rmed that PLZT powders synthesized by sol-gel method had smaller grains and better dispersion. The atmosphere sintering and spark plasma sintering（SPS）technique were used to sinter the PLZT ceramics separately. After sintering, the physical, electrical, and optical properties of the PLZT ceramics sintered by di?erent methods were tested. The results show that the SPS sintering can increase the densi?cation degree (reaching 99.5%)of the PLZT ceramics, which improved the transparency, ferroelectric, piezoelectric and optical properties of PLZT ceramics. It is found that when the light intensity reached 600 mW/cm2, the max- ?3, which was almost 1.4 imum photo-induced strain of the SPS sintered ceramic was as high as 10. 84 × 10 times larger than that of the atmosphere-sintered sample. Obviously, the sol-gel method and SPS process can enhance the comprehensive performance of PLZT ceramics.
关键词： Photo-induced strain,Ferroelectric/piezoelectric property,Sol-gel method,PLZT,SPS
更新于2025-09-09 09:28:46
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - The SPS and an alternative ring design as pre-booster of FCC e+e? injector
摘要： The FCC-e+e? injector complex needs to produce and to transport a high-intensity e+/e? beam at a fast repetition rate for topping up the collider at its collision energy. Two di?erent options are under consideration as pre-accelerator before the bunches are transferred to the high-energy booster: using the existing SPS and a completely new ring. The purpose of this paper is to present the necessary modi?cations of the existing SPS which is mainly adding damping and Robinson wigglers to reach the required emittance for SPS and the updates on conceptual design of an alternative accelerator ring with injection and extraction energies of 6 and 20 GeV, respectively. In this study, the main parameters of both choices are established, including the optics design and layout updates.
关键词： SPS,Robinson wiggler,FCC-e+e? injector,pre-booster ring,alternative ring design,damping wiggler
更新于2025-09-04 15:30:14