| 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. |
- Zhao, Yaofeng, et al.
(författare)
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Ornithorhynchus anatinus (Platypus) Links the Evolution of Immunoglobulin Genes in Eutherian Mammals and Nonmammalian Tetrapods
- 2009
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 183:5, s. 3285-3293
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Tidskriftsartikel (refereegranskat)abstract
- The evolutionary origins of mammalian immunoglobulin H chain isotypes (IgM, IgD, IgG, IgE, and IgA) are still incompletely understood as these isotypes differ considerably in structure and number from their counterparts in nonmammalian tetrapods. We report in this study that the platypus (Ornithorhynchus anatinus) Ig H chain constant region gene locus contains eight Ig encoding genes, which are arranged in an mu-delta-o-gamma 2-gamma 1-alpha 1-epsilon-alpha 2 order, spanning a total of similar to 200 kb DNA, encoding six distinct isotypes. The o (o for Ornithorhynchus) gene encodes a novel Ig H chain isotype that consists of four constant region domains and a hinge, and is structurally different from any of the five known mammalian Ig classes. This gene is phylogenetically related to nu (epsilon) and gamma, and thus appears to be a structural intermediate between these two genes. The platypus delta gene encodes ten heavy chain constant region domains, lacks a hinge region and is similar to IgD in amphibians and fish, but strikingly different from that in eutherian mammals. The platypus Ig H chain isotype repertoire thus shows a unique combination of genes that share similarity both to those of nonmammallian tetrapods and eutherian animals and demonstrates how phylogenetically informative species can be used to reconstruct the evolutionary history of functionally important genes.
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| 3. |
- Chen, Youchun, et al.
(författare)
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Insights into the working mechanism of cathode interlayers in polymer solar cells via [(C8H17)(4)N](4)[SiW12O40]
- 2016
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 4:48, s. 19189-19196
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Tidskriftsartikel (refereegranskat)abstract
- A low-cost (amp;lt;$1 per g), high-yield (amp;gt;90%), alcohol soluble surfactant-encapsulated polyoxometalate complex [(C8H17)(4)N](4)[SiW12O40] has been synthesized and utilized as a cathode interlayer (CIL) in polymer solar cells (PSCs). A power conversion efficiency of 10.1% can be obtained for PSCs based on PTB7-Th (poly[[2,6-4,8-di(5-ethylhexylthienyl) benzo[1,2-b;3,3-b]-dithiophene][3-fluoro-2[(2-ethylhexyl) carbonyl] thieno [3,4-b]-thiophenediyl]]):PC71BM ([6,6]-phenyl C71-butyric acidmethyl ester) due to the incorporation of [(C8H17)(4)N](4)[SiW12O40]. Combined measurements of current density-voltage characteristics, transient photocurrent, charge carrier mobility and capacitance-voltage characteristics demonstrate that [(C8H17)(4)N](4)[SiW12O40] can effectively increase the built-in potential, charge carrier density and mobility and accelerate the charge carrier extraction in PSCs. Most importantly, the mechanism of using [(C8H17)(4)N](4)[SiW12O40] as the CIL is further brought to light by X-ray photoemission spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS) of the metal/ [(C8H17)(4)N](4)[SiW12O40] interface. The findings suggest that [(C8H17)(4)N](4)[SiW12O40] not only decreased the work function of the metal cathodes but also was n-doped upon contact with the metals, which provide insights into the working mechanism of the CILs simultaneously improving the open circuit voltage, short circuit current and fill factor in the PSCs.
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| 4. |
- Fan, Qunping, 1989, et al.
(författare)
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A Non-Conjugated Polymer Acceptor for Efficient and Thermally Stable All-Polymer Solar Cells
- 2020
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Ingår i: Angewandte Chemie - International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 59:45, s. 19835-19840
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Tidskriftsartikel (refereegranskat)abstract
- A non-conjugated polymer acceptor PF1-TS4 was firstly synthesized by embedding a thioalkyl segment in the mainchain, which shows excellent photophysical properties on par with a fully conjugated polymer, with a low optical band gap of 1.58 eV and a high absorption coefficient >105 cm−1, a high LUMO level of −3.89 eV, and suitable crystallinity. Matched with the polymer donor PM6, the PF1-TS4-based all-PSC achieved a power conversion efficiency (PCE) of 8.63 %, which is ≈45 % higher than that of a device based on the small molecule acceptor counterpart IDIC16. Moreover, the PF1-TS4-based all-PSC has good thermal stability with ≈70 % of its initial PCE retained after being stored at 85 °C for 180 h, while the IDIC16-based device only retained ≈50 % of its initial PCE when stored at 85 °C for only 18 h. Our work provides a new strategy to develop efficient polymer acceptor materials by linkage of conjugated units with non-conjugated thioalkyl segments.
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| 5. |
- Meng, Yuan, et al.
(författare)
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Influence of land use type and urbanization level on the distribution of pharmaceuticals and personal care products and risk assessment in Beiyun River, China
- 2021
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Ingår i: Chemosphere. - : Pergamon Press. - 0045-6535 .- 1879-1298. ; 287:Pt 1
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Tidskriftsartikel (refereegranskat)abstract
- Influence of land use type and urbanization level on the distribution of pharmaceuticals and personal care products (PPCPs) from the developed regions of Beijing-Tianjin-Hebei in the northern China was evaluated. The seasonal and spatial variations of the 22 target PPCPs were analyzed in the 63 sampling sites along the whole Beiyun River Basin. Results showed that the total PPCPs concentration had a wide variation range, from 132 ng L-1 to 25474 ng L-1. Spatial interpolation analysis showed that agricultural land presented higher PPCPs contamination level than build-up land (p < 0.05) and the concentration was negatively correlated with urbanization level. Source apportionment showed the untreated sewage source contributed to 34%-53% of the PPCPs burden in the Beiyun River. Risk assessment indicated that diethyltoluamide, carbamazepine, octocrylene, gemfibrozil and triclocarban had high risks (RQ > 1), and small tributaries had the highest mixed risk (MRQ = 34). Species sensitivity distribution combined with the safety threshold method showed that PPCPs would have potential risk on aquatic organisms even at very low concentrations and triclocarban posed the highest risk in the Beiyun River.
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| 6. |
- Wu, Chuanyan, et al.
(författare)
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PEPRF : Identification of Essential Proteins by Integrating Topological Features of PPI Network and Sequence-based Features via Random Forest
- 2021
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Ingår i: Current Bioinformatics. - : Bentham Science Publishers Ltd.. - 1574-8936. ; 16:9, s. 1161-1168
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Tidskriftsartikel (refereegranskat)abstract
- Background: Essential proteins play an important role in the process of life, which can be identified by experimental methods and computational approaches. Experimental approaches to identify essential proteins are of high accuracy but with the limitation of time and resource-consuming. Objective: Herein, we present a computational model (PEPRF) to identify essential proteins based on machine learning. Methods: Different features of proteins were extracted. Topological features of Protein-Protein Interaction (PPI) network-based are extracted. Based on the protein sequence, graph theory-based features, in-formation-based features, composition and physichemical features, etc., were extracted. Finally, 282 features are constructed. In order to select the features that contributed most to the identification, Re-liefF-based feature selection method was adopted to measure the weights of these features. Results: As a result, 212 features were curated to train random forest classifiers. Finally, PEPRF get the AUC of 0.71 and an accuracy of 0.742. Conclusion: Our results show that PEPRF may be applied as an efficient tool to identify essential pro-teins.
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| 7. |
- Xu, Feng, et al.
(författare)
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Broadband spectroscopic sensor for real-time monitoring of industrial SO2 emissions
- 2007
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Ingår i: Applied Optics. - 2155-3165. ; 46:13, s. 2503-2506
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Tidskriftsartikel (refereegranskat)abstract
- A spectroscopic system for continuous real-time monitoring of SO2, concentrations in industrial emissions was developed. The sensor is well suited for field applications due to simple and compact instrumental design, and robust data evaluation based on ultraviolet broadband absorption without the use of any calibration cell. The sensor has a detection limit of 1 ppm, and was employed both for gas-flow simulations with and without suspended particles, and for in situ measurement of SO2 concentrations in the flue gas emitted from an industrial coal-fired boiler. The price/performance ratio of the instrument is expected to be superior to other comparable real-time monitoring systems.
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| 8. |
- Yu, Chuanhe, et al.
(författare)
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A mechanism for preventing asymmetric histone segregation onto replicating DNA strands
- 2018
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Ingår i: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 361:6409, s. 1386-+-
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Tidskriftsartikel (refereegranskat)abstract
- How parental histone (H3-H4)2 tetramers, the primary carriers of epigenetic modifications, are transferred onto leading and lagging strands of DNA replication forks for epigenetic inheritance remains elusive. Here we show that parental (H3-H4)2 tetramers are assembled into nucleosomes onto both leading and lagging strands, with a slight preference for lagging strands. The lagging strand preference increases markedly in cells lacking Dpb3 and Dpb4, two subunits of the leading strand DNA polymerase, Pol ε, due to the impairment of parental (H3-H4)2 transfer to leading strands. Dpb3-Dpb4 binds H3-H4 in vitro and participates in the inheritance of heterochromatin. These results indicate that different proteins facilitate the transfer of parental (H3-H4)2 onto leading vs lagging strands, and that Dbp3-Dpb4 plays a significant role in this poorly understood process.
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| 9. |
- Biemont, E, et al.
(författare)
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Doubly ionized thorium: Laser lifetime measurements and transition probability determination of interest in cosmochronology
- 2002
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 567:2, s. 1276-1283
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Tidskriftsartikel (refereegranskat)abstract
- The first lifetime measurements have been performed for six levels of doubly ionized thorium, an important cosmochronometer in astrophysics for estimating the age of the Galaxy. The levels, belonging to the 5f(2), 5f7p, 7s7p, and 6d7p configurations of Th III, have been measured by the time-resolved laser-induced fluorescence method and compared with relativistic Hartree-Fock calculations including configuration interaction and core-polarization effects. Taking advantage of the excellent agreement between theory and experiment, a first set of transition probabilities of astrophysical interest has been deduced for this ion from a combination of the experimental lifetimes and of the theoretical branching fractions.
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| 10. |
- Biemont, E, et al.
(författare)
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Lifetime measurements and calculations in singly ionized ytterbium
- 2002
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075. ; 35:22, s. 4743-4749
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Tidskriftsartikel (refereegranskat)abstract
- New radiative lifetimes, measured by time-resolved laser-induced fluorescence spectroscopy, are reported for five Rydberg states of singly ionized ytterbium. Free Yb+ ions were produced in a laser-induced plasma. The experimental results have been compared with HFR calculations, taking core-polarization effects into account, and a good agreement (within 25%) between theory and experiment is observed for four levels. HFR results are also proposed for np (n less than or equal to 7) and nf (n less than or equal to 8) Rydberg states and compared with available data.
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