| 1. |
- Chi, Xiaoming, et al.
(författare)
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Fractal superconducting nanowire single-photon detectors with reduced polarization sensitivity
- 2018
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Ingår i: Optics Letters. - : OPTICAL SOC AMER. - 0146-9592 .- 1539-4794. ; 43:20, s. 5017-5020
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate superconducting nanowire single-photon detectors (SNSPDs) based on a fractal design of the nanowires to reduce the polarization sensitivity of detection efficiency. We patterned niobium titanium nitride thin films into Peano curves with a linewidth of 100 nm and integrated the nanowires with optical microcavities to enhance their optical absorption. At a base temperature of 2.6 K, the fractal SNSPD exhibited a polarization-maximum device efficiency of 67% and a polarization-minimum device efficiency of 61% at a wavelength of 1550 nm. Therefore, the polarization sensitivity, defined as their ratio, was 1.1, lower than the polarization sensitivity of the SNSPDs in the meander design. The reduced polarization sensitivity of the detector could be maintained for higher-order spatial modes in multimode optical fibers and could tolerate misalignment between the optical mode and the detector. This fractal design is applicable to both amorphous and polycrystalline materials that are commonly used for making SNSPDs.
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| 2. |
- Hu, Shih-Cheng, et al.
(författare)
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Energy savings approaches for high-tech manufacturing factories
- 2020
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Ingår i: CASE STUDIES IN THERMAL ENGINEERING. - : ELSEVIER. - 2214-157X. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- This study integrates a fab energy simulation (FES) tool and energy conversion factors to analyze energy consumption and identify energy savings opportunities of high-tech manufacturing factories. The data used is the 169,124 MW h annual energy consumption of a Taiwanese semiconductor manufacturing fab. We proposed a compressed/clean dry air (CDA) system as a two-pressure system using a heated-type dryer. The proposed method achieved 3050 MW h as the highest energy savings in the CDA system compared to the original fab data. The results also indicate that lowering the make-up air unit (MAU) operating temperature caused significant energy savings for the high-temperature water chiller system. When the outlet air temperature of the MAU system was 14 degrees C, the maximum energy savings were 3532 MW h. In addition, the process cooling water (PCW) system could potentially save energy by reducing the pumping head of water in its open system. Therefore, we suggested a closed PCW system that reached a maximum energy saving of 1541 MW h.
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| 3. |
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| 4. |
- Zhang, Jiao, et al.
(författare)
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Joint Resource Allocation for Latency-Sensitive Services Over Mobile Edge Computing Networks With Caching
- 2019
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Ingår i: IEEE Internet of Things Journal. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2327-4662. ; 6:3, s. 4283-4294
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Tidskriftsartikel (refereegranskat)abstract
- Mobile edge computing (MEC) has risen as a promising paradigm to provide high quality of experience via relocating the cloud server in close proximity to smart mobile devices (SMDs). In MEC networks, the MEC server with computation capability and storage resource can jointly execute the latency-sensitive offloading tasks and cache the contents requested by SMDs. In order to minimize the total latency consumption of the computation tasks, we jointly consider computation offloading, content caching, and resource allocation as an integrated model, which is formulated as a mixed integer nonlinear programming (MINLP) problem. We design an asymmetric search tree and improve the branch and bound method to obtain a set of accurate decisions and resource allocation strategies. Furthermore, we introduce the auxiliary variables to reformulate the proposed model and apply the modified generalized benders decomposition method to solve the MINLP problem in polynomial computation complexity time. Simulation results demonstrate the superiority of the proposed schemes.
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| 5. |
- Wang, Ling, et al.
(författare)
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Defect formation by order coalescence in vermicular grains during alumina phase transformation
- 2015
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Ingår i: Scripta Materialia. - : Elsevier BV. - 1359-6462 .- 1872-8456. ; 107, s. 59-62
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Tidskriftsartikel (refereegranskat)abstract
- Vermicular alpha-Al2O3 grains obtained from gamma- to alpha-phase transformation were investigated. X-ray diffraction patterns showed a left-shifting shoulder in all diffraction peaks of transformed alpha-Al2O3. High-resolution transmission electron microscopy results confirmed large amounts of defects inside the vermicular alpha-Al2O3 single-crystal. Combined with grain-growth discontinuity, the authors proposed that the defects inside vermicular grains resulted from assembly of nanosized alpha-crystallites by an ordered coalescence mechanism directly after phase transformation, by which the orientation alignment was thermodynamically favored in the solid-state sintering.
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| 6. |
- Yue, C., et al.
(författare)
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Modeling of the effective thermal conductivity of composite materials with FEM based on resistor networks approach
- 2010
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Ingår i: Microsystem Technologies. - : Springer Science and Business Media LLC. - 0946-7076 .- 1432-1858. ; 16:4, s. 633-639
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Tidskriftsartikel (refereegranskat)abstract
- In the present paper, a novel and efficient model was developed for predicting the effective thermal conductivity of the composite materials at different filler percentages. By introducing the relative radius as a parameter, the effective thermal conductivity can be predicted precisely when the thermal properties of filler and matrix are prescribed. The model employed the resistor network strategy to achieve a highly efficient prediction during the overall conductivity calculation. To verify this model, a wide range of two-phase composites, including Cu/PP, AlN/PI and a self-developed thermal conductive adhesive, were analyzed. The model-based simulation values showed good agreement with the experimental results. Moreover, a discussion on the effects of the newly-introduced parameter was given. Finally, the relationship between the filler radius variation and the thermal conductivity of the composite was studied.
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| 7. |
- Zhu, Y., et al.
(författare)
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Synchronization of a class of networked passive systems with switching topology
- 2007
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Ingår i: Proceedings of the 46th IEEE Conference on Decision and Control. - 1424414989 - 9781424414987 ; , s. 2271-2276
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Konferensbidrag (refereegranskat)abstract
- This paper considers the output synchronization of a class of networked agents. Each agent is a passive system. Local information, used by each agent to adjust its movement, forms a network with switching adjacent topology. First, we consider the asymptotic stability of nonlinear time-varying switched systems by using multiple Lyapunov function. An extended Lyapunov-like Lemma for switched systems is obtained. Then the result is applied to the output synchronization of a class of networked passive systems with switching topology. A pretty fair sufficient condition is presented.
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| 8. |
- Cheng, W., et al.
(författare)
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Mitigation of ultrafine particulate matter emission from agricultural biomass pellet combustion by the additive of phosphoric acid modified kaolin
- 2021
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Ingår i: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 172, s. 177-187
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Tidskriftsartikel (refereegranskat)abstract
- The emission of ultrafine particulate matter (PM0.2) originated from the agricultural biomass pellet combustion poses great threat to atmospheric environment and human health, which restricts its large-scale utilization. In this study, a new phosphoric acid modification method is proposed to improve the PM0.2 reduction efficiency by kaolin additive. The effects of phosphoric acid concentration and treatment time on the physicochemical properties of kaolin and on the mitigation of PM0.2 emission from the pellet combustion are investigated. Results indicate that phosphoric acid modification destroy the internal structure of kaolin by the leaching of Al cations and the formation of active free silica. Meanwhile, the pore structure increases after modification with residual P deposited on the surface, which results in better alkali capture ability of modified kaolin. With the addition of phosphoric acid modified kaolin, significant reduction of PM0.2 emission can be achieved and the reduction ratio is proportional to the acid concentration. The maximum PM0.2 emission reduction ratio reaches 64.5% for the kaolin additive modified by 12 mol/L phosphoric acid for 6 hours. Finally, the PM0.2 reduction mechanism is proposed based on the analysis results, which provides technical knowhow for the industrial application of agricultural biomass pellet combustion.
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| 9. |
- Fang, Cheng, et al.
(författare)
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An Autoclavable and Transparent Thermal Cutter for Reliably Sealing Wet Nanofibrous Membranes
- 2024
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 24:28, s. 8709-8716
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Tidskriftsartikel (refereegranskat)abstract
- Sealing wet porous membranes is a major challenge when fabricating cell encapsulation devices. Herein, we report the development of an Autoclavable Transparent Thermal Cutter (ATTC) for reliably sealing wet nanofibrous membranes. Notably, the ATTC is autoclavable and transparent, thus enabling in situ visualization of the sealing process in a sterile environment and ensuring an appropriate seal. In addition, the ATTC could generate smooth, arbitrary-shaped sealing ends with excellent mechanical properties when sealing PA6, PVDF, and TPU nanofibrous tubes and PP microporous membranes. Importantly, the ATTC could reliably seal wet nanofibrous tubes, which can shoulder a burst pressure up to 313.2 +/- 19.3 kPa without bursting at the sealing ends. Furthermore, the ATTC sealing process is highly compatible with the fabrication of cell encapsulation devices, as verified by viability, proliferation, cell escape, and cell function tests. We believe that the ATTC could be used to reliably seal cell encapsulation devices with minimal side effects.
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| 10. |
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