| 1. |
- Pecunia, Vincenzo, et al.
(författare)
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Roadmap on energy harvesting materials
- 2023
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Ingår i: Journal of Physics. - : IOP Publishing. - 2515-7639. ; 6:4
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Tidskriftsartikel (refereegranskat)abstract
- Ambient energy harvesting has great potential to contribute to sustainable development and address growing environmental challenges. Converting waste energy from energy-intensive processes and systems (e.g. combustion engines and furnaces) is crucial to reducing their environmental impact and achieving net-zero emissions. Compact energy harvesters will also be key to powering the exponentially growing smart devices ecosystem that is part of the Internet of Things, thus enabling futuristic applications that can improve our quality of life (e.g. smart homes, smart cities, smart manufacturing, and smart healthcare). To achieve these goals, innovative materials are needed to efficiently convert ambient energy into electricity through various physical mechanisms, such as the photovoltaic effect, thermoelectricity, piezoelectricity, triboelectricity, and radiofrequency wireless power transfer. By bringing together the perspectives of experts in various types of energy harvesting materials, this Roadmap provides extensive insights into recent advances and present challenges in the field. Additionally, the Roadmap analyses the key performance metrics of these technologies in relation to their ultimate energy conversion limits. Building on these insights, the Roadmap outlines promising directions for future research to fully harness the potential of energy harvesting materials for green energy anytime, anywhere.
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| 2. |
- Wei, Yi-Ming, et al.
(författare)
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Responsibility accounting in carbon allocation : A global perspective
- 2014
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 130, s. 122-133
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Tidskriftsartikel (refereegranskat)abstract
- Regarding the carbon emissions allocation principles, whether historical responsibility can be and how to be incorporated into the global climate framework is still under heated discussions. Here we argue that the permits share of most developed countries will sharply shrink when historical responsibilities are taken in through our assessment and comparison of six selected allocation proposals. To find a more convincing way of responsibility shift, we modify the existing method by giving each participant an independent year, decided by comparing its economic development with reference to China, as the start point to calculate its own responsibilities quantified by the historical cumulative emissions. Then we obtain carbon emission accounts of 137 countries and regions on the basis of per-capita cumulative emissions. Compared with the conventional method, there is an average 2.5% increase in emission deficits of the U.S.A, Canada and Japan, however, a 50% decline in emission deficits of OECD Europe; emission revenues of China, India and Brazil decrease by 39%. This paper presents a systematic and quantitative method to achieve a common but differentiated responsibility shift, not only between developed and developing countries but also within industrialized countries, in the hope of providing the framework for rational allocation of carbon emissions to be deliberated in the forthcoming climate change program of the United Nations.
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| 3. |
- Cai, Lili, et al.
(författare)
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Optimization of aluminum/silicon compounds on fire resistance of old corrugated container fiber foam material
- 2016
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Ingår i: BioResources. - : BioResources. - 1930-2126 .- 1930-2126. ; 11:3, s. 6505-6517
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Tidskriftsartikel (refereegranskat)abstract
- Old corrugated container fiber foam material (OCCM) was prepared using a liquid frothing approach. The effect of the content of Al/Si compounds, the molar ratio of Al3+/SiO2, and different addition form on the limited oxygen index (LOI) and residue percentage of OCCM was optimized using an orthogonal design. The fire resistance of OCCM was best when the content of Al/Si compounds was 900 mL, the molar ratio of Al3+/SiO2 was 1:1, and the aluminum sulfate solution was added first, followed by the separately added sodium silicate solution. Under these conditions, the LOI and residue percentage of OCCM reached 32.3 and 53.51%, respectively. Thermogravimetric analysis indicated that Al/Si compounds promoted char formation and reduced the heat release of the optimized OCCMs during depolymerisation. Compared with the control group, the residue percentage of optimized OCCM was increased from 12.49% to 37.98%. Fourier transform infrared spectroscopy identified the functional groups of Al/Si compounds in the optimized OCCMs, confirming that pyrolysis of the optimized OCCMs was affected by Al/Si compounds.
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| 4. |
- Jia, Xue, et al.
(författare)
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CsPb(IxBr1-x)(3) solar cells
- 2019
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Ingår i: Science Bulletin. - : ELSEVIER. - 2095-9273. ; 64:20, s. 1532-1539
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Tidskriftsartikel (refereegranskat)abstract
- Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell (PSC) becomes a promising candidate for next-generation high-efficiency solar cells. The power conversion efficiency (PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(IxBr1-x)(3) and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(IxBr1-x)(3) solar cells and outline possible directions to further improve the device performance. (C) 2019 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.
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| 5. |
- Wu, Zhenzeng, et al.
(författare)
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Optimization for fire performance of ultra-low density fiberboards using response surface methodology
- 2017
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Ingår i: BioResources. - : North Carolina State University. - 1930-2126 .- 1930-2126. ; 12:2, s. 3790-3800
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Tidskriftsartikel (refereegranskat)abstract
- The optimization of the process conditions for fire retardant ultra-low density fiberboards (ULDFs) was investigated using response surface methodology (RSM). Three parameters, namely those of Borax-Zinc-Silicate-Aluminum (B-Zn-Si-Al), chlorinated paraffin (CP), and chloride-vinyl chloride emulsions (PVDC) were chosen as variables. The considerably high R2 value (99.98%) indicated the statistical significance of the model. The optimal process conditions for the limiting oxygen index (LOI) were determined by analyzing the response surface's three-dimensional surface plot and contour plot, and by solving the regression model equation with Design Expert software. The Box-Behnken design (BBD) was used to optimize the process conditions, which showed that the most favorable dosages of B-Zn-Si-Al, CP, and PVDC were 800 mL, 46.47 mL, and 35.64 g, respectively. Under the optimized conditions, the maximum LOI was 48.4.
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| 6. |
- Lu, Xin, et al.
(författare)
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A generic and modularized Digital twin enabled human-robot collaboration
- 2022
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Ingår i: Proceedings 2022 IEEE International Conference on e-Business Engineering ICEBE 2022. - : IEEE. - 9781665492447 - 9781665492454 ; , s. 66-73
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Konferensbidrag (refereegranskat)abstract
- Recently, the manufacturing paradigm shifts from mass production to mass customization, which results in urgently demands for the development of intelligent, flexible and automatic manufacturing systems for handling complex manufacturing tasks with high efficiency. The use of collaborative robots, an essential enabling technology for developing human-robot collaboration (HRC), is on the rise for human-centric intelligent automation design. An effective virtual simulation platform, which can continuously simulate and evaluate HRC performance in different working scenarios, is lacking in developing an HRC system in a sophisticated industrial arena. This paper presents a generic and modularized digital twin enabled HRC framework based on the synergy effect of human, robotic and environment-related factors to provide a flexible, compatible, re-configurable solution to ease the implementation of HRC in the real world. The feasibility of the proposed framework is validated through the practical implementation of a food packaging job, which involves a human operator and an ABB robotic arm collaboratively working together, on an industrial shop.
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| 7. |
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| 8. |
- Jiang, Jin-gang, et al.
(författare)
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Medical robotics
- 2015
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Ingår i: Advances in Mechanical Engineering. - : SAGE Publications. - 1687-8132 .- 1687-8140. ; 7:7
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Wang, Zicun, et al.
(författare)
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Intelligent Beam Training with Deep Convolutional Neural Network in mmWave Communications
- 2022
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Ingår i: 2022 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM 2022). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 1223-1228
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Konferensbidrag (refereegranskat)abstract
- Highly directional beams in millimeter wave (mmWave) communications necessitate beam training or alignment between the access point (AP) and the user equipment (UE), and exhausted beam search (EBS) method is suggested in the current 3GPP standard. Nevertheless, EBS suffers from high overheads and inevitably lowers the throughput, especially when the beam space is large. In this paper, we utilize the spatial correlation among different beams as well as the strong feature extraction/representation capability of the deep convolutional neural network (CNN), and propose an intelligent beam training algorithm. With the proposed method, the AP can probe only a fixed subset of the whole beam space and identify the optimal beam intelligently. Simulation results show that, the proposed method can largely reduce the overheads for the beam training meanwhile boost the throughput performance compared with the state of the arts.
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| 10. |
- Zhao, Ming, 1975-
(författare)
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Growth and Characterization of Strain-engineered Si/SiGe Heterostructures Prepared by Molecular Beam Epitaxy
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The strain introduced by lattice mismatch is a built-in characteristic in Si/SiGe heterostructures, which has significant influences on various material properties. Proper design and precise control of strain within Si/SiGe heterostructures, i.e. the so-called “strain engineering”, have become a very important way not only for substantial performance enhancement of conventional microelectronic devices, but also to allow novel device concepts to be integrated with Si chips for new functions, e.g. Si-based optoelectronics. This thesis thus describes studies on two subjects of such strain-engineered Si/SiGe heterostructures grown by molecular beam epitaxy (MBE). The first one focuses on the growth and characterizations of delicately strain-symmetrized Si/SiGe multi-quantum-well/superlattice structures on fully relaxed SiGe virtual substrates for light emission in the THz frequency range. The second one investigates the strain relaxation mechanism of thin SiGe layers during MBE growth and post-growth processes in non-conventional conditions.Two types of THz emitters, based on different quantum cascade (QC) intersubband transition schemes, were studied. The QC emitters using the diagonal transition between two adjacent wells were grown with Si/Si0.7Ge0.3 superlattices up to 100 periods. It was shown that nearly perfect strain symmetry in the superlattice with a high material quality was obtained. The layer parameters were precisely controlled with deviations of ≤ 2 Å in layer thickness and ≤ 1.5 at. % in Ge composition from the designed values. The fabricated emitter devices exhibited a dominating emission peak at ~13 meV (~3 THz), which was consistent with the design. An attempt to produce the first QC THz emitter based on the bound-to-continuum transition was made. The structures with a complicated design of 20 periods of active units were extremely challenging for the growth. Each unit contained 16 Si/Si0.724Ge0.276 superlattice layers, in which the thinnest one was only 8 Å. The growth parameters were carefully studied, and several samples with different boron δ-doping concentrations were grown at optimized conditions. Extensive material characterizations revealed a high crystalline quality of the grown structures with an excellent growth control, while the heavy δ-doping may introduce layer undulations as a result of the non-uniformity in the strain field. Moreover, carrier lifetime dynamics, which is crucial for the THz QC structure design, was also investigated. Strain-symmetrized Si/SiGe multi-quantum-well structures, designed for probing the carrier lifetime of intersubband transitions inside a well between heavy hole 1 (HH1) and light hole 1 (LH1) states with transition energies below the optical phonon energy, were grown on SiGe virtual substrates. The lifetime of the LH1 excited state was determined directly with pump-probe spectroscopy. The measurements indicated an increase of lifetime by a factor of ~2 due to the increasingly unconfined LH1 state, which agreed very well with the theory. It also showed a very long lifetime of several hundred picoseconds for the holes excited out of the well to transit back to the well through a diagonal process.Strained SiGe grown on Si (110) substrates has promising potentials for high-speed microelectronics devices due to the enhanced carrier mobility. Strain relaxation of SiGe/Si(110) subjected to different annealing treatments was studied by X-ray reciprocal space mapping. The in-plane lattice mismatch was found to be asymmetric with the major strain relaxation observed in the lateral [001] direction. It was concluded that this was associated to the formation and propagation of conventional a/2<110> dislocations oriented along [110]. This was different from the relaxation observed during growth, which was mainly along in-plane [110].A novel MBE growth process to fabricate thin strain-relaxed Si0.6Ge0.4 virtual substrates involving low-temperature (LT) buffer layers was investigated. At a certain LT-buffer growth temperature, a dramatic increase in the strain relaxation accompanied with a decrease of surface roughness was observed in the top SiGe, together with a cross-hatch/cross-hatch-free transition in the surface morphology. It was explained by the association with a certain onset stage of the ordered/disordered transition during the growth of the LT-SiGe buffer.
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