| 1. |
- You, Xiaohu, et al.
(författare)
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Towards 6G wireless communication networks: vision, enabling technologies, and new paradigm shifts
- 2021
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Ingår i: Science China Information Sciences. - : Science Press. - 1674-733X .- 1869-1919. ; 64:1
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Forskningsöversikt (refereegranskat)abstract
- The fifth generation (5G) wireless communication networks are being deployed worldwide from 2020 and more capabilities are in the process of being standardized, such as mass connectivity, ultra-reliability, and guaranteed low latency. However, 5G will not meet all requirements of the future in 2030 and beyond, and sixth generation (6G) wireless communication networks are expected to provide global coverage, enhanced spectral/energy/cost efficiency, better intelligence level and security, etc. To meet these requirements, 6G networks will rely on new enabling technologies, i.e., air interface and transmission technologies and novel network architecture, such as waveform design, multiple access, channel coding schemes, multi-antenna technologies, network slicing, cell-free architecture, and cloud/fog/edge computing. Our vision on 6G is that it will have four new paradigm shifts. First, to satisfy the requirement of global coverage, 6G will not be limited to terrestrial communication networks, which will need to be complemented with non-terrestrial networks such as satellite and unmanned aerial vehicle (UAV) communication networks, thus achieving a space-air-ground-sea integrated communication network. Second, all spectra will be fully explored to further increase data rates and connection density, including the sub-6 GHz, millimeter wave (mmWave), terahertz (THz), and optical frequency bands. Third, facing the big datasets generated by the use of extremely heterogeneous networks, diverse communication scenarios, large numbers of antennas, wide bandwidths, and new service requirements, 6G networks will enable a new range of smart applications with the aid of artificial intelligence (AI) and big data technologies. Fourth, network security will have to be strengthened when developing 6G networks. This article provides a comprehensive survey of recent advances and future trends in these four aspects. Clearly, 6G with additional technical requirements beyond those of 5G will enable faster and further communications to the extent that the boundary between physical and cyber worlds disappears.
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| 2. |
- Kristan, Matej, et al.
(författare)
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The Visual Object Tracking VOT2015 challenge results
- 2015
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Ingår i: Proceedings 2015 IEEE International Conference on Computer Vision Workshops ICCVW 2015. - : IEEE. - 9780769557205 ; , s. 564-586
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge 2015, VOT2015, aims at comparing short-term single-object visual trackers that do not apply pre-learned models of object appearance. Results of 62 trackers are presented. The number of tested trackers makes VOT 2015 the largest benchmark on short-term tracking to date. For each participating tracker, a short description is provided in the appendix. Features of the VOT2015 challenge that go beyond its VOT2014 predecessor are: (i) a new VOT2015 dataset twice as large as in VOT2014 with full annotation of targets by rotated bounding boxes and per-frame attribute, (ii) extensions of the VOT2014 evaluation methodology by introduction of a new performance measure. The dataset, the evaluation kit as well as the results are publicly available at the challenge website(1).
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| 3. |
- Li, Zheng, et al.
(författare)
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A Review of Spatter in Laser Powder Bed Fusion Additive Manufacturing: In Situ Detection, Generation, Effects, and Countermeasures
- 2022
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Ingår i: Micromachines. - : MDPI AG. - 2072-666X. ; 13:8
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Forskningsöversikt (refereegranskat)abstract
- Spatter is an inherent, unpreventable, and undesired phenomenon in laser powder bed fusion (L-PBF) additive manufacturing. Spatter behavior has an intrinsic correlation with the forming quality in L-PBF because it leads to metallurgical defects and the degradation of mechanical properties. This impact becomes more severe in the fabrication of large-sized parts during the multi-laser L-PBF process. Therefore, investigations of spatter generation and countermeasures have become more urgent. Although much research has provided insights into the melt pool, microstructure, and mechanical property, reviews of spatter in L-PBF are still limited. This work reviews the literature on the in situ detection, generation, effects, and countermeasures of spatter in L-PBF. It is expected to pave the way towards a novel generation of highly efficient and intelligent L-PBF systems.
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| 4. |
- Hu, Jiandong, et al.
(författare)
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Development of a Surface Plasmon Resonance Biosensing Approach for the Rapid Detection of Porcine Circovirus Type2 in Sample Solutions
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:10, s. e111292-
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Tidskriftsartikel (refereegranskat)abstract
- A sensitive and label-free analytical approach for the detection of porcine circovirus type 2 (PCV2) instead of PCV2 antibody in serum sample was systematically investigated in this research based on surface plasmon resonance (SPR) with an establishment of special molecular identification membrane. The experimental device for constructing the biosensing analyzer is composed of an integrated biosensor, a home-made microfluidic module, and an electrical control circuit incorporated with a photoelectric converter. In order to detect the PCV2 using the surface plasmon resonance immunoassay, the mercaptopropionic acid has been used to bind the Au film in advance through the known form of the strong S-Au covalent bonds formed by the chemical radical of the mercaptopropionic acid and the Au film. PCV2 antibodies were bonded with the mercaptopropionic acid by covalent -CO-NH- amide bonding. For the purpose of evaluating the performance of this approach, the known concentrations of PCV2 Cap protein of 10 mu g/mL, 7.5 mu g/mL, 5 mu g/mL, 2.5 mu g/mL, 1 mu g/mL, and 0.5 mu g/mL were prepared by diluting with PBS successively and then the delta response units (Delta RUs) were measured individually. Using the data collected from the linear CCD array, the Delta RUs gave a linear response over a wide concentration range of standard known concentrations of PCV2 Cap protein with the R-Squared value of 0.99625. The theoretical limit of detection was calculated to be 0.04 mu g/mL for the surface plasmon resonance biosensing approach. Correspondingly, the recovery rate ranged from 81.0% to 89.3% was obtained. In contrast to the PCV2 detection kits, this surface plasmon resonance biosensing system was validated through linearity, precision and recovery, which demonstrated that the surface plasmon resonance immunoassay is reliable and robust. It was concluded that the detection method which is associated with biomembrane properties is expected to contribute much to determine the PCV2 in sample solutions instead of PCV2 antibody in serum samples quantitatively.
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| 5. |
- Liang, Wang, et al.
(författare)
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Life cycle assessment of blast furnace ironmaking processes : A comparison of fossil fuels and biomass hydrochar applications
- 2023
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 345
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Tidskriftsartikel (refereegranskat)abstract
- The impact of the iron and steel production process on the ecological environment cannot be ignored. This study aims to assess the impact of life cycle assessment on the traditional fossil fuel blast furnace ironmaking process and the biomass hydrochar blast furnace ironmaking process. The Simapro v9.0 software is used to comprehensively evaluate the life cycle impacts of biomass hydrochar in the blast furnace ironmaking process. The results show that the life cycle impact categories of the blast furnace ironmaking process mainly include global warming, non-renewable energy and respiratory inorganics. The global warming impact of the ironmaking process using hydrochar is 2054.00 kg CO2 eq, which is 420.61 kg CO2 eq less than that of traditional blast furnace ironmaking process. The global warming impact is mainly reflected in the emission of CO2 gas, and the main source is the generation of blast furnace gas and the use of sinter. The respiratory inorganics impact is mainly manifested in the emission of nitrogen oxides, sulfur oxides and particulates, which mainly comes from the mining of iron ore and the production of sinter. The non-renewable energy impact mainly comes from the coal resources, and the use of other renewable energy such as biomass energy is an important way to reduce the impact. Therefore, biomass hydrochar used in the metallurgical process is more suitable for sustainable devel-opment of the ecological environment.
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| 6. |
- Liang, Yongqi, et al.
(författare)
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Achieving High Open-Circuit Voltages up to 1.57 V in Hole-Transport-Material-Free MAPbBr(3) Solar Cells with Carbon Electrodes
- 2018
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Ingår i: Advanced Energy Materials. - : Wiley-VCH Verlagsgesellschaft. - 1614-6832 .- 1614-6840. ; 8:4
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Tidskriftsartikel (refereegranskat)abstract
- An open-circuit voltage (V-oc) of 1.57 V under simulated AM1.5 sunlight in planar MAPbBr(3) solar cells with carbon (graphite) electrodes is obtained. The hole-transport-material-free MAPbBr(3) solar cells with the normal architecture (FTO/TiO2/MAPbBr(3)/carbon) show little hysteresis during current-voltage sweep under simulated AM1.5 sunlight. A solar-to-electricity power conversion efficiency of 8.70% is achieved with the champion device. Accordingly, it is proposed that the carbon electrodes are effective to extract photogenerated holes in MAPbBr(3) solar cells, and the industry-applicable carbon electrodes will not limit the performance of bromide-based perovskite solar cells. Based on the analysis of the band alignment, it is found that the voltage (energy) loss across the interface between MAPbBr(3) and carbon is very small compared to the offset between the valence band maximum of MAPbBr(3) and the work function of graphite. This finding implies either Fermi level pinning or highly doped region inside MAPbBr(3) layer exists. The band-edge electroluminescence spectra of MAPbBr(3) from the solar cells further support no back-transfer pathways of electrons across the MAPbBr(3)/TiO2 interface.
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| 7. |
- Wang, Chang, et al.
(författare)
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Molecular beam epitaxy growth of AlAs 1-x Bi x
- 2019
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 34:3
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Tidskriftsartikel (refereegranskat)abstract
- High quality AlAs 1-x Bi x layers with Bi composition of 3%-10.5% have been successfully grown by molecular beam epitaxy. The Bi incorporation is confirmed by Rutherford backscattering spectroscopy. For a 400 nm thick AlAsBi layer, the strain relaxation occurs when the Bi composition is larger than 6.5%. Flux ratio is calculated from Knudsen-cell model and Maxwell equation, according to the geometrical relationship of our equipment. The Bi incorporation increases with increasing the As-Al flux ratio as well as the Bi flux. The extrapolation lattice constant of hypothetic zincblende AlBi alloy is about 6.23 Å.
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| 8. |
- Wang, Shu Min, 1963, et al.
(författare)
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Progress on III-V-Bi Alloys and Light Emitting Devices
- 2018
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Ingår i: International Conference on Transparent Optical Networks. - 2162-7339. ; 2018-July
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Konferensbidrag (refereegranskat)abstract
- In this invited talk, we will present some recent progresses on epitaxial growth of III-V-Bi alloys and light emitting devices. Aluminum containing bismides including AlAsBi and AlSbBi have been epitaxially grown for the first time and their physical properties will be reported. New designs of using delta-doping in quantum wells are investigated to effectively extend light emission wavelength. Finally, GaAs based light emitting diode will be presented.
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| 9. |
- Zhao, Yun, et al.
(författare)
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Rational design of functional binder systems for high-energy lithium-based rechargeable batteries
- 2021
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Ingår i: Energy Storage Materials. - : Elsevier. - 2405-8289 .- 2405-8297. ; 35, s. 353-377
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Tidskriftsartikel (refereegranskat)abstract
- Binders, which maintain the structural integrity of electrodes, are critical components of lithium-based rechargeable batteries (LBRBs) that significantly affect battery performances, despite accounting for 2 to 5 wt% (up to 5 wt% but usually 2 wt%) of the entire electrode. Traditional polyvinylidene fluoride (PVDF) binders that interact with electrode components via weak van der Waals forces are effective in conventional LBRB systems (graphite/LiCoO2, etc.). However, its stable fluorinated structures limit the potential for further functionalization and inhibit strong interactions towards external substances. Consequently, they are unsuitable for next-generation battery systems with high energy density. There is thus a need for new functional binders with facile features compatible with novel electrode materials and chemistries. Here in this review we consider the strategies for rationally designing these functional binders. On the basis of fundamental understandings of the issues for high-energy electrode materials, we have summarized seven desired functions that binders should possess depending on the target electrodes where the binders will be applied. Then a variety of leading-edge functional binders are reviewed to show how their chemical structures realize these above functions and how the employment of these binders affects the cell's electrochemical performances. Finally the corresponding design strategies are therefore proposed, and future research opportunities as well as challenges relating to LBRB binders are outlined.
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| 10. |
- Bartocci, Pietro, et al.
(författare)
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Bioenergy with Carbon Capture and Storage (BECCS) developed by coupling a Pressurised Chemical Looping combustor with a turbo expander: How to optimize plant efficiency
- 2022
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Ingår i: Renewable and Sustainable Energy Reviews. - : Elsevier BV. - 1879-0690 .- 1364-0321. ; 169
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Forskningsöversikt (refereegranskat)abstract
- Carbon Capture and Storage is a technology of paramount importance for the fulfillment of the Sustainable Development Goal 7 (Affordable and Clean Energy) and the Sustainable Development Goal 5 (Climate Action). The European Union is moving rapidly towards low carbon technologies, for instance via the Energy Union Strategy. Coupling biofuels and carbon capture and storage to decarbonize the power and the industrial sector can be done through the development of BECCS (Bioenergy with Carbon Capture and Storage). Chemical Looping combustion is one of the cheapest way to capture CO2. A Chemical Looping Combustion (CLC) plant can be coupled with a turbo expander to convert energy to power, but it has to work in pressurised conditions. The effect of pressure on the chemical reactions and on fluidised bed hydrodynamics, at the moment, is not completely clear. The aim of this review is to summarize the most important highlights in this field and also provide an original method to optimize power plant efficiency. The main objective of our research is that to design a pressurised Chemical Looping Combustion plant which can be coupled to a turbo expander. To achieve this we need to start from the characteristics of the turbo expander itself (eg. the Turbine Inlet Temperature and the compression ratio) and then design the chemical looping combustor with a top down approach. Once the air and the fuel reactor have been dimensioned and the oxygen carrier inventory and circulation rate have been identified, the paper proposes a final optimization procedure based on two energy balances applied to the two reactors. The results of this work propose an optimization methodology and guidelines to be used for the design of pressurised chemical looping reactors to be coupled with turbo expanders for the production of power with carbon negative emissions.
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