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Implementation of Metallic Vertical Interconnect Access in Hybrid Intercalated Graphene/Quantum Dot Photodetector for Improved Charge Collection
摘要： Performance improvement of heat recovery-based power generation (HRPG) systems puzzles researchers due to the implicitly coupled property. This contribution builds the heat current model of a HRPG system and applies the circuit principle to derive its heat transfer and conversion constraints. Then, derivation of the flow resistance balance equations describes the pressure distribution in circulation loop. Combining with the relations between fluid temperatures and pressures constructs the integrated system model. Based on the separation of linear topology equations and explicit nonlinear component equations from implicit nonlinear constraints using heat current model, this contribution introduces a fast and stable divide-and-conquer solution scheme, which solves linear equations in iterations and updates the iterative variables by substitutions. Finally, optimization of the fluid flow rates for the maximum net electricity generation under different working conditions shows the superiority of the heat current method over the commercial software Ebsilon. The optimized results show that a smaller mass flow rate of flue gas leads to lower optimal evaporation and condensation pressures, while the optimal dryness fraction of exhaust steam is almost unchanged. Besides, the constant backpressure operation strategy apparently deviates from the optima, and the maximum deviation reaches 8.6%.
关键词： Energy conservation,Heat recovery-based power generation,Solution scheme,Heat current model,Global optimization
更新于2025-09-19 17:13:59
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[Institution of Engineering and Technology 5th IET International Conference on Clean Energy and Technology (CEAT2018) - Kuala Lumpur, Malaysia (5-6 Sept. 2018)] 5th IET International Conference on Clean Energy and Technology (CEAT2018) - Conducting Polymers: New Arena in Dye-sensitized Solar Cells
摘要： The combined heat and power (CHP) systems can provide heat and electricity simultaneously. They are promising in the future energy landscape because of high efficiency and low emissions. This paper proposes a new operation optimization model of CHPs in deregulated energy markets. Both CHPs’ overall efficiency and heat to electricity ratio are closely linked with the loading level, which are dynamically determined in this paper. A discrete optimization model is then proposed to determine the optimal real-time operation strategies for the CHPs. The optimization problem is solved by the interior point method with discrete time intervals, in which the discrete optimal operation points can be identified effectively. This step projects the potential operation strategies that could produce maximum benefits. Finally, a dynamic programming algorithm is developed to maximize the profits of CHPs through dynamically modifying the operation strategies projected in the previous step considering transient constraints. The proposed new methodology is demonstrated on a 1-MW CHP system with real-time data.
关键词： heat to electricity (H2E) ratio,operation optimization model,Combined heat and power (CHP),maximum benefits,dynamic programming
更新于2025-09-19 17:13:59
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Analysis and Optimization of a Microchannel Heat Sink with V-Ribs Using Nanofluids for Micro Solar Cells
摘要： It is crucial to control the temperature of solar cells for enhancing e?ciency with the increasing power intensity of multiple photovoltaic systems. In order to improve the heat transfer e?ciency, a microchannel heat sink (MCHS) with V-ribs using a water-based nano?uid as a coolant for micro solar cells was designed. Numerical simulations were carried out to investigate the ?ows and heat transfers in the MCHS when the Reynolds number ranges from 200 to 1000. The numerical results showed that the periodically arranged V-ribs can interrupt the thermal boundary, induce chaotic convection, increase heat transfer area, and subsequently improve the heat transfer performance of a MCHS. In addition, the preferential values of the geometric parameters of V-ribs and the physical parameters of the nano?uid were obtained on the basis of the Nusselt numbers at identical pump power. For MCHS with V-ribs on both the top and bottom wall, preferential values of V-rib are rib width d/W = 1, ?are angle α = 75°, rib height hr/H = 0.3, and ratio of two slant sides b/a = 0.75, respectively. This can provide sound foundations for the design of a MCHS in micro solar cells.
关键词： nano?uid,heat transfer enhancement,micro solar cell,microchannel heat sink,V-ribs
更新于2025-09-19 17:13:59
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Coherent control of a GaAs quantum dot spin qubit operated in a feedback loop
摘要： The combined heat and power (CHP) systems can provide heat and electricity simultaneously. They are promising in the future energy landscape because of high efficiency and low emissions. This paper proposes a new operation optimization model of CHPs in deregulated energy markets. Both CHPs’ overall efficiency and heat to electricity ratio are closely linked with the loading level, which are dynamically determined in this paper. A discrete optimization model is then proposed to determine the optimal real-time operation strategies for the CHPs. The optimization problem is solved by the interior point method with discrete time intervals, in which the discrete optimal operation points can be identified effectively. This step projects the potential operation strategies that could produce maximum benefits. Finally, a dynamic programming algorithm is developed to maximize the profits of CHPs through dynamically modifying the operation strategies projected in the previous step considering transient constraints. The proposed new methodology is demonstrated on a 1-MW CHP system with real-time data.
关键词： heat to electricity (H2E) ratio,operation optimization model,Combined heat and power (CHP),maximum benefits,dynamic programming
更新于2025-09-19 17:13:59
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Understanding the thermal process during laser assisted ultra-high frequency induction deposition with wire feeding
摘要： This study proposes a novel metal deposition method referred to as laser assisted ultra-high frequency induction (UHF) deposition. In this method, the UHF induction heat is used as the main heat source to melt the deposited metal, and the laser heat acts as an auxiliary heat source that provides a high-temperature substrate surface for efficient fusion between the deposited metal and substrate. A numerical model coupled with electromagnetic and temperature fields is developed to understand the thermal process of laser assisted UHF induction deposition. The thermal process with different combination states of the two heat sources is numerically investigated to reveal the influence mechanism of the two heat sources on the penetration depth of the deposited layer. Results show that the UHF induction heat increases the penetration depth of the deposited layer by raising the temperature of the deposited metal, and laser heat leads to an increment in penetration depth by providing a high substrate surface temperature. Decreasing the distance between the laser beam and metal wire also increases the substrate surface temperature, thereby increasing the penetration depth. Criteria for characteristic temperatures T peak1 , T peak2 , and T interval are proposed based on thermal process analysis to control thermal process and prevent the deposited layer from having a large penetration depth. Deposition experiments reveal the process feasibility of the proposed deposition method and validate the numerical model. The performance evaluation of the deposited layers proves that controlling the thermal process is the key for ensuring the performance of the deposited layer. The numerical model and criteria for characteristic temperatures provide an efficient way for controlling the thermal process during deposition; thus, reasonable performance of the deposited layer can be ensured.
关键词： Numerical simulation,Deposition,Thermal process,Ultra-high frequency (UHF) induction heat
更新于2025-09-19 17:13:59
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Microstructure of intercritical heat affected zone and toughness of microalloyed steel laser welds
摘要： Microstructure of laser welds of the X70 low-carbon pipe steel was studied. High cooling rates after laser welding and non-uniform distribution of carbon in the ferrite-pearlite base metal caused formation of regions with increased microhardness (up to 650 НV) in inter-critical heat affected zone (ICHAZ). These regions consisted of finely dispersed degenerate upper bainite and martensite-austenite constituents of a slender shape and small fraction of a massive shape along the boundaries of bainite laths, as well as twinned martensite. High concentration of martensite-austenite constituents (10–16%) and residual stresses in ICHAZ, as well as a dendritic martensitic structure with carbide interlayers along the boundaries of martensite laths in fusion zone were the main reasons of sharp decrease in charpy impact energy of the welded samples. High microhardness of the laser welds was decreased down to 320 HV and their brittleness was improved by annealing. Also, in ICHAZ, degenerate upper bainite and the regions of martensite-austenite constituents decayed forming tempered sorbite and Fe2C and Fe3C carbides, respectively. Charpy impact energy of the welds doubled after annealing compared to the welds without annealing, and ductile-brittle transition temperature decreased down to –60 °С.
关键词： Toughness,Heat affected zone,Structure,Laser welding,Low-carbon steel
更新于2025-09-19 17:13:59
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Amplified spontaneous emission and random lasing using CsPbBr3 quantum dots glass through controlling crystallization
摘要： By increasing the heat treatment temperature, the average size of CsPbBr3 quantum dots (QDs) in the glass matrix was increased, which contribute to the 5.5 folds increase of the optical gain coefficients. And the corresponding lasing threshold can decrease from 0.752 mJ/cm2 to 0.138 mJ/cm2.
关键词： CsPbBr3 quantum dots,glass matrix,heat treatment temperature,optical gain coefficients,lasing threshold
更新于2025-09-19 17:13:59
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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) - Metamaterials, Anapoles and Flying Donuts
摘要： Heat-assisted magnetic recording (HAMR) allows for data writing in hard disks beyond 1 Tb/in2 areal density, by temporarily heating the area of a single bit to its Curie temperature. The metallic optical antenna or near-?eld transducer (NFT), used to apply the nanoscale heating to the media, may self-heat by several hundreds of degrees. With the NFT reaching such extreme temperatures, demonstrations of HAMR technology experience write-head lifetimes that are orders of magnitude less than that required for a commercial product. Hence, heating of the NFT is of upmost importance. In this paper, we ?rst derive fundamental limits on the temperature ratio NFT/Media to drive NFT design choices for low-temperature operation. Next, we employ inverse electromagnetic design software, which solves for unexpected geometries of the NFT and waveguide. We present computationally generated designs for the waveguide feeding the NFT that offer a 50% reduction in NFT self-heating (～220 °C) compared with typical industry designs.
关键词： HAMR,optimization,plasmonics,nanophotonics,near-?eld transducer (NFT),inverse problem,heat-assisted magnetic recording thermal,computational electromagnetics,hard disks,gradient methods,management,Adjoint method,optical antenna
更新于2025-09-19 17:13:59
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Characterization of a vertical crack using Laser Spot Thermography
摘要： This paper deals with the solution of an inverse problem for the heat equation aimed at nondestructive evaluation of fractures, emerging on the accessible surface of a slab, by means of Active Thermography. In real life, this surface is heated with a laser and its temperature is measured for a time interval by means of an infrared camera. A fundamental step in iterative inversion methods is the numerical solution of the underlying direct mathematical model. Usually, this step requires specific techniques in order to limit an abnormal use of memory resources and computing time due to excessively fine meshes necessary to follow a very thin fracture in the domain. Our contribution to this problem consists in decomposing the temperature of the damaged specimen as a sum of a term (with known analytical form) due to an infinite virtual fracture and the solution of an initial boundary value problem for the heat equation on one side of the fracture (i.e. on a rectangular domain). The depth of the fracture is a variable parameter in the boundary conditions that must be estimated from additional data (usually, measurements of the surface temperature). We apply our method to the detection of simulated cracks in concrete and steel specimens.
关键词： finite elements,heat equation,crack,Inverse problems,active thermography
更新于2025-09-19 17:13:59
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Gambogic Acid Augments Black Phosphorus Quantum Dots (BPQDs)-Based Synergistic Chemo-Photothermal Therapy through Downregulating Heat Shock Protein Expression
摘要： In an attempt to attain synergistic therapeutic benefits and address various intrinsic limitations of the highly efficient black phosphorus quantum dots (BPQDs), we fabricated poly(L-lactide)-poly(ethylene glycol)-poly(L-lactide) triblock copolymer (PLLA-PEG-PLLA)-based nanocomposites co-loaded with BPQDs and gambogic acid (GA) using the supercritical carbon dioxide (SC-CO2) technology to achieve photoacoustic (PA) imaging-guided synergistic chemo-photothermal therapy. On the one hand, BPQDs displayed near-infrared (NIR)-induced hyperthermia through the high photothermal conversion efficiency. On the other hand, the NIR-responsive release of GA facilitated early apoptosis through specific binding to stress-induced overexpression of heat shock protein (HSP)-90 for combating thermoresistant tumor cells. GA significantly promoted the photothermal therapy (PTT) efficiency by enhancing both early and late apoptosis of BPQDs. Moreover, the encapsulation of BPQDs in the polymer significantly improved their chemical as well as photothermal stabilities. Our findings suggested that these nanocomposites fabricated using the eco-friendly supercritical fluid (SCF) technology provided good protection to the biodegradable BPQDs, offering a great potential towards cancer ablation through augmented synergistic effects.
关键词： Synergism,NIR-responsive,Black phosphorus,Heat shock protein,Photothermal therapy
更新于2025-09-19 17:13:59