The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting p...The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting process with vanadium slag.In this work,CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples were prepared and roasted for different time periods to illustrate and compare the diffusion reaction mechanisms.Then,the changes in the diffusion product and diffusion coefficient were investigated and calculated based on scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) analysis.Results show that with the extension of the roasting time,the diffusion reaction gradually proceeds among the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples.The regional boundaries of calcium and vanadium are easily identifiable for the CaO–V_(2)O_(5) diffusion couple.Meanwhile,for the MnO_(2)–V_(2)O_(5) diffusion couple,MnO_(2) gradually decomposes to form Mn_(2)O_(3),and vanadium diffuses into the interior of Mn_(2)O_(3).Only a part of vanadium combines with manganese to form the diffusion production layer.CaV_(2)O_(6) and MnV_(2)O_(6) are the interfacial reaction products of the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples,respectively,whose thicknesses are 39.85 and 32.13μm when roasted for 16 h.After 16 h,both diffusion couples reach the reaction equilibrium due to the limitation of diffusion.The diffusion coefficient of the CaO–V_(2)O_(5) diffusion couple is higher than that of the MnO_(2)–V_(2)O_(5) diffusion couple for the same roasting time,and the diffusion reaction between vanadium and calcium is easier than that between vanadium and manganese.展开更多
In this paper, the performance of hybrid precoding is investigated for mmWave massive MIMO systems with different antenna arrays. The hybrid precoding with partially connected architecture (PCA) is adopted. The spectr...In this paper, the performance of hybrid precoding is investigated for mmWave massive MIMO systems with different antenna arrays. The hybrid precoding with partially connected architecture (PCA) is adopted. The spectral efficiency (SE) and received energy efficiency (EE) are investigated by considering four types of antenna arrays, including uniform linear array (ULA), uniform rectangular planar array (URPA), uniform hexagonal planar array (UHPA), and uniform circular planar array (UCPA), respectively. We focus on analysis at the antenna response vector and utilize the idea of orthogonal matching pursuit algorithm to seek the optimal hybrid precoder. Furthermore, the trade-off of precoding architectures is studied between SE and received EE. Simulation results show that if the uniform planar array antenna is more concentrated, the SE and receive EE will be higher. Considering SE and received EE, the performance of planar arrays outperform linear array. There exist different optimal radio-frequency chain numbers to maximize the SE for planar array and linear array. In addition, the PCA can achieve relatively higher received EE while the SE is close to the fully connected architecture and the full digital architecture.展开更多
The unicellular green alga Chlamydomonas reinhardtii(hereafter Chlamydomonas)possesses both plant and animal attributes,and it is an ideal model organism for studying fundamental processes such as photosynthesis,sexua...The unicellular green alga Chlamydomonas reinhardtii(hereafter Chlamydomonas)possesses both plant and animal attributes,and it is an ideal model organism for studying fundamental processes such as photosynthesis,sexual reproduction,and life cycle.N^(6)-methyladenosine(m^(6)A)is the most prevalent mRNA modification,and it plays important roles during sexual reproduction in animals and plants.However,the pattern and function of m^(6)A modification during the sexual reproduction of Chlamydomonas remain unknown.Here,we performed transcriptome and methylated RNA immunoprecipitation sequencing(MeRIP-seq)analyses on six samples from different stages during sexual reproduction of the Chlamydomonas life cycle.The results show that m^(6)A modification frequently occurs at the main motif of DRAC(D=G/A/U,R=A/G)in Chlamydomonas mRNAs.Moreover,m^(6)A peaks in Chlamydomonas mRNAs are mainly enriched in the 30 untranslated regions(30 UTRs)and negatively correlated with the abundance of transcripts at each stage.In particular,there is a significant negative correlation between the expression levels and the m^(6)A levels of genes involved in the microtubule-associated pathway,indicating that m^(6)A modification influences the sexual reproduction and the life cycle of Chlamydomonas by regulating microtubule-based movement.In summary,our findings are the first to demonstrate the distribution and the functions of m^(6)A modification in Chlamydomonas mRNAs and provide new evolutionary insights into m^(6)A modification in the process of sexual reproduction in other plant organisms.展开更多
While total internal reflection(TIR)lays the foundation for many important applications,foremost fibre optics that revolutionised information technologies,it is undesirable in some other applications such as light-emi...While total internal reflection(TIR)lays the foundation for many important applications,foremost fibre optics that revolutionised information technologies,it is undesirable in some other applications such as light-emitting diodes(LEDs),which are a backbone for energy-efficient light sources.In the case of LEDs,TIR prevents photons from escaping the constituent high-index materials.Advances in material science have led to good efficiencies in generating photons from electron–hole pairs,making light extraction the bottleneck of the overall efficiency of LEDs.In recent years,the extraction efficiency has been improved,using nanostructures at the semiconductor/air interface that outcouple trapped photons to the outside continuum.However,the design of geometrical features for light extraction with sizes comparable to or smaller than the optical wavelength always requires sophisticated and timeconsuming fabrication,which causes a gap between lab demonstration and industrial-level applications.Inspired by lightning bugs,we propose and realise a disordered metasurface for light extraction throughout the visible spectrum,achieved with single-step fabrication.By applying such a cost-effective light extraction layer,we improve the external quantum efficiency by a factor of 1.65 for commercialised GaN LEDs,demonstrating a substantial potential for global energy-saving and sustainability.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52174277 and 51874077)the Fundamental Funds for the Central Universities,China(No.N2225032)+1 种基金the China Postdoctoral Science Foundation(No.2022M720683)the Postdoctoral Fund of Northeastern University,China。
文摘The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting process with vanadium slag.In this work,CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples were prepared and roasted for different time periods to illustrate and compare the diffusion reaction mechanisms.Then,the changes in the diffusion product and diffusion coefficient were investigated and calculated based on scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) analysis.Results show that with the extension of the roasting time,the diffusion reaction gradually proceeds among the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples.The regional boundaries of calcium and vanadium are easily identifiable for the CaO–V_(2)O_(5) diffusion couple.Meanwhile,for the MnO_(2)–V_(2)O_(5) diffusion couple,MnO_(2) gradually decomposes to form Mn_(2)O_(3),and vanadium diffuses into the interior of Mn_(2)O_(3).Only a part of vanadium combines with manganese to form the diffusion production layer.CaV_(2)O_(6) and MnV_(2)O_(6) are the interfacial reaction products of the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples,respectively,whose thicknesses are 39.85 and 32.13μm when roasted for 16 h.After 16 h,both diffusion couples reach the reaction equilibrium due to the limitation of diffusion.The diffusion coefficient of the CaO–V_(2)O_(5) diffusion couple is higher than that of the MnO_(2)–V_(2)O_(5) diffusion couple for the same roasting time,and the diffusion reaction between vanadium and calcium is easier than that between vanadium and manganese.
基金supported by the National Natural Science Foundation of China (No.61961018)the Jiangxi Province Foundation for Distinguished Young Scholar (No.20192BCB23013)+1 种基金the Jiangxi Province Natural Science Foundation of China (No.20171BAB202001, 20192ACB21003)the Science Program of Jiangxi Educational Committee (No.GJJ180307)
文摘In this paper, the performance of hybrid precoding is investigated for mmWave massive MIMO systems with different antenna arrays. The hybrid precoding with partially connected architecture (PCA) is adopted. The spectral efficiency (SE) and received energy efficiency (EE) are investigated by considering four types of antenna arrays, including uniform linear array (ULA), uniform rectangular planar array (URPA), uniform hexagonal planar array (UHPA), and uniform circular planar array (UCPA), respectively. We focus on analysis at the antenna response vector and utilize the idea of orthogonal matching pursuit algorithm to seek the optimal hybrid precoder. Furthermore, the trade-off of precoding architectures is studied between SE and received EE. Simulation results show that if the uniform planar array antenna is more concentrated, the SE and receive EE will be higher. Considering SE and received EE, the performance of planar arrays outperform linear array. There exist different optimal radio-frequency chain numbers to maximize the SE for planar array and linear array. In addition, the PCA can achieve relatively higher received EE while the SE is close to the fully connected architecture and the full digital architecture.
基金supported by the National Key R&D Program of China(Grant Nos.2019YFA0904600,2018YFA0801200,and 2021YFA0910800)the National Natural Science Foundation of China(Grant Nos.31870217 and 91940304).
文摘The unicellular green alga Chlamydomonas reinhardtii(hereafter Chlamydomonas)possesses both plant and animal attributes,and it is an ideal model organism for studying fundamental processes such as photosynthesis,sexual reproduction,and life cycle.N^(6)-methyladenosine(m^(6)A)is the most prevalent mRNA modification,and it plays important roles during sexual reproduction in animals and plants.However,the pattern and function of m^(6)A modification during the sexual reproduction of Chlamydomonas remain unknown.Here,we performed transcriptome and methylated RNA immunoprecipitation sequencing(MeRIP-seq)analyses on six samples from different stages during sexual reproduction of the Chlamydomonas life cycle.The results show that m^(6)A modification frequently occurs at the main motif of DRAC(D=G/A/U,R=A/G)in Chlamydomonas mRNAs.Moreover,m^(6)A peaks in Chlamydomonas mRNAs are mainly enriched in the 30 untranslated regions(30 UTRs)and negatively correlated with the abundance of transcripts at each stage.In particular,there is a significant negative correlation between the expression levels and the m^(6)A levels of genes involved in the microtubule-associated pathway,indicating that m^(6)A modification influences the sexual reproduction and the life cycle of Chlamydomonas by regulating microtubule-based movement.In summary,our findings are the first to demonstrate the distribution and the functions of m^(6)A modification in Chlamydomonas mRNAs and provide new evolutionary insights into m^(6)A modification in the process of sexual reproduction in other plant organisms.
基金P.M.and M.H.acknowledge the financial support from by National Natural Science Foundation of China(Grant No.11627806,U1909214,11604161)the National Key R&D Program of China(Grant No.2016YFA0201002)+5 种基金P.M.acknowledges the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant(Grant No.752102)C.L.acknowledges the financial support from Humboldt Research Fellowship from Alexander von Humboldt Foundation.P.M.,C.L.and S.Z acknowledge 2020 European Research Council Project Nos.734578(D-SPA)and 648783(TOPOLOGICAL)Leverhulme Trust(grant no.RPG-2012-674)the Royal Society,the Wolfson Foundation.S.A.M.acknowledges funding support from the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy,EXC 2089/1-390776260the Solar Energies go Hybrid(SolTech)programme,the EPSRC Reactive Plasmonics Programme(EP/M013812/1)the Lee-Lucas Chair in Physics.X.L.,M.L.and E.S.acknowledge financial support from the Natural Sciences and Engineering Research Council(NSERC)of Canada.
文摘While total internal reflection(TIR)lays the foundation for many important applications,foremost fibre optics that revolutionised information technologies,it is undesirable in some other applications such as light-emitting diodes(LEDs),which are a backbone for energy-efficient light sources.In the case of LEDs,TIR prevents photons from escaping the constituent high-index materials.Advances in material science have led to good efficiencies in generating photons from electron–hole pairs,making light extraction the bottleneck of the overall efficiency of LEDs.In recent years,the extraction efficiency has been improved,using nanostructures at the semiconductor/air interface that outcouple trapped photons to the outside continuum.However,the design of geometrical features for light extraction with sizes comparable to or smaller than the optical wavelength always requires sophisticated and timeconsuming fabrication,which causes a gap between lab demonstration and industrial-level applications.Inspired by lightning bugs,we propose and realise a disordered metasurface for light extraction throughout the visible spectrum,achieved with single-step fabrication.By applying such a cost-effective light extraction layer,we improve the external quantum efficiency by a factor of 1.65 for commercialised GaN LEDs,demonstrating a substantial potential for global energy-saving and sustainability.
