Massive multiple-input multiple-output(MIMO) system is capable of substantially improving the spectral efficiency as well as the capacity of wireless networks relying on equipping a large number of antenna elements at...Massive multiple-input multiple-output(MIMO) system is capable of substantially improving the spectral efficiency as well as the capacity of wireless networks relying on equipping a large number of antenna elements at the base stations. However, the excessively high computational complexity of the signal detection in massive MIMO systems imposes a significant challenge for practical hardware implementations. In this paper, we propose a novel minimum mean square error(MMSE) signal detection using the accelerated overrelaxation(AOR) iterative method without complicated matrix inversion, which is capable of reducing the overall complexity of the classical MMSE algorithm by an order of magnitude. Simulation results show that the proposed AOR-based method can approach the conventional MMSE signal detection with significant complexity reduction.展开更多
With Oreochromis niloticus as the object of study,glucose was added as a carbon source to promote the formation of the biological flocs for replacing part of the feed,and three gradients were set up,namely Group A(all...With Oreochromis niloticus as the object of study,glucose was added as a carbon source to promote the formation of the biological flocs for replacing part of the feed,and three gradients were set up,namely Group A(all feed),Group B(replacement of 10%feed)and Group C(replacement of 20%feed),so as to explore the effects of photosynthetic bacteria-enhanced biological flocs on tilapia growth and water environment conditions.Meanwhile,the Biolog-ECO technology was applied to study the changes of microbial carbon metabolism diversity in aquaculture water.The results showed that the utilization of microbial carbon sources under different feed replacement gradients increased with the extension of the culture time.The overall performance was in order of 10%replacement>all feed>20%feed replacement.A suitable replacement rate could not only enhance the overall utilization of carbon sources by water microorganisms,but also save culture costs.The principal component analysis showed that the carbon source metabolism of the water microbial communities under different feed replacement gradients was significantly different.Specifically,polysaccharides,esters and amino acids were the preferred carbon sources of water microbes,while the utilization of amines and acids was low.展开更多
The rapid deactivation of cost-effective MnO_(2)-based catalysts in humid air limits their application in practice,and the identification of the role of water in an oxidation process is significant for developing wate...The rapid deactivation of cost-effective MnO_(2)-based catalysts in humid air limits their application in practice,and the identification of the role of water in an oxidation process is significant for developing water-resistant MnO_(2)-based catalysts.Here,CuMnO_(2)showed a20.3%HCHO conversion in 10 hr at room temperature in humid air with relative humidity of 40%,but deactivated in 3 hr in dry air.The excellent activity and stability of HCHO oxidation in humid air were attributed to the positive effect of H_(2)O on HCHO oxidation to the H_(2)O-HOCH_(2)OH supermolecule assemblies via hydrogen bonds formed on CuMnO_(2).H_(2)O-HOCH_(2)OH supermolecule assemblies tend to be oxidized to carbonate,which is further oxidized to CO_(2).Furthermore,CuMnO_(2)exhibited a much poorer activity of CO oxidation in humid air,but the CO conversion was still 100%in 10 hr in dry air.H_(2)O showed a competitive adsorption effect to CO on CuMnO_(2).CuMnO_(2)could be applied in HCHO elimination in humid air and CO elimination in dry air.展开更多
Background Immunization is one of the most far-reaching and cost-effective strategies for promoting good health and saving lives.A complex immunization schedule,however,may be burdensome to parents and lead to reduced...Background Immunization is one of the most far-reaching and cost-effective strategies for promoting good health and saving lives.A complex immunization schedule,however,may be burdensome to parents and lead to reduced vaccine compliance and completion.Thus,it is critical to develop combination vaccines to reduce the number of injections and simplify the immunization schedule.This study aimed to investigate the current status of the pentavalent diphtheria-tetanus-acellular pertussis inactivated poliomyelitis andHaemophilus influenzae type B conjugate(DTaP-IPV/Hib)vaccination in Southern China as well as explore the factors in the general population associated with uptake and the differences between urban and rural populations.Methods A cross-sectional study was conducted with recently enrolled kindergarten students in Hainan Province between December 2022 and January 2023.The study employed a stratified multistage cluster random sampling method.Information regarding the demographic characteristics and factors that influence decisions were collected from the caregivers of children via an online questionnaire.Multivariate logistic regression was used to determine the factors associated with the status of DTap-IPV/Hib vaccinations.Results Of the 4818 valid responses,95.3%of children were aged 3-4 years,and 2856(59.3%)held ruralhukou.Coverage rates of the DTaP-IPV/Hib vaccine,from 1 to 4 doses,were 24.4%,20.7%,18.5%,and 16.0%,respectively.Caregivers who are concerned about vaccine efficacy[adjusted odds ratio(aOR)=1.53,95%confidence interval(CI):1.30-1.79],the manufacturer(aOR=2.05,95%CI:1.69-2.49),and a simple immunization schedule(aOR=1.26,95%CI:1.04-1.54)are factors associated with a higher likelihood of vaccinating children against DTaP-IPV/Hib.In addition,caregivers in urban areas showed more concern about the vaccine price(P=0.010)and immunization schedule(P=0.022)in regard to vaccinating children.Conclusions The DTaP-IPV/Hib vaccine coverage rate in Hainan Province remains low.Factors such as lower socioeconomic status,cultural beliefs,concerns about vaccine safety,and cost may hinder caregivers from vaccinating their children.Further measures,such as health education campaigns to raise knowledge and awareness,and encouragement of domestic vaccine innovation,which would reduce out-of-pocket costs,could be implemented to improve the coverage of DTap-IPV/Hib vaccination.展开更多
of main observation and conclusion The heterojunction-type structure has shown significant merits in tuning the optical properties and carrier physics.Inspired by the excellent absorption capability of halide perovski...of main observation and conclusion The heterojunction-type structure has shown significant merits in tuning the optical properties and carrier physics.Inspired by the excellent absorption capability of halide perovskite materials for visible light,a series of CsPbBr3/TiO2 heterojunction-type photocatalysts with various all-inorganic-perovskite/TiO2 ratios are successfully fabricated by the ligand-assisted reprecipitation(LARP)method.The heterojunction structure extends the light absorption of TiO2 with good chemical and structural stability.A Pb-O interaction at the CsPbBr3/TiO2 interface is observed by the XPS and confirmed by the TRPL showing improved interface carrier transport and stability.The heterojunction-type catalyst shows drastically enhanced photocatalytic activity towards the direct oxidation of toluene with 02 molecule,as an important reaction for organic chemical synthesis.The optimized sample shows an activity of 2356μmol·g^-1·h^-1 at 75℃,4 times of that of the naked CsPbBr3 nanocrystals,and 3 times of that of the bare TiO2.Based on the investigation with trapping agents,a reaction mechanism is hence proposed suggesting that the photo-generated hole may be involved in the rate-limiting step.This work demonstrates the potential of inorganic halide perovskite-based heterojunction structure for photocatalytic applications.展开更多
The catalysts supported on LiA1508 （spinel） for vapor phase synthesis of dimethyl carbonate （DMC） from methyl nitrite （MN） have been studied. Their catalytic activities on supports prepared by different methods ...The catalysts supported on LiA1508 （spinel） for vapor phase synthesis of dimethyl carbonate （DMC） from methyl nitrite （MN） have been studied. Their catalytic activities on supports prepared by different methods were evaluated in a continuous reactor. The samples were characterized by powder X-ray diffraction, N2 adsorption-desorption isotherms, fourier transform infrared spectroscopy and temperature-programmed reduction of H2. Li/A1 molar ratio and calcination temperature greatly influence the structure of crystalline phase of Li-AI-O oxides. Desirable LiAIsO8 （spinel） was formed at 800℃, while LiA1508 （primitive cube） formed at 900℃ is undesirable for the reaction. A high Li/A1 molar ratio, which was related with LiA102, also slowed the reaction rate. The electron transfer ability and the interaction with active component are the important properties of the spinel-based supports. The CuC12-PdC12/LiAIsO8 （spinel） with better electron transfer ability and low Pd2＋ reduction temperature exhibited a better catalytic ability.展开更多
In terms of photoelectrochemical(PEC)hydrogen evolution,substantial challenge still remains regarding the controllable fabrication of quantum dots(QDs)-sensitized photocathodes with enhanced visible-light absorption,e...In terms of photoelectrochemical(PEC)hydrogen evolution,substantial challenge still remains regarding the controllable fabrication of quantum dots(QDs)-sensitized photocathodes with enhanced visible-light absorption,efficient charge carrier separation,and directional migration at the electrode interface.In this work,the CdTe/CdSe QDs-sensitized photocathodes were delicately constructed on p-type NiO-coated indium tin oxide(ITO)electrodes by spin-coating approach.The resulting co-sensitized photocathode exhibits a favorable pseudo-Type Ⅱ energetic band alignment that combines the advantages of strong light absorption of constituent QDs as well as the effective and oriented charge separation and migration.Upon green LED light illumination,the photogenerated electrons could be effectively transferred to a tetra-nickel-substituted polyoxometalate catalyst for hydrogen production while photogenerated holes will be scavenged at the NiO/ITO electrode.Under minimally optimized conditions,the pseudo-Type Ⅱ CdTe/CdSe-sensrtized photocathode yields a photcx:urrent density of over 100 pA/cm^(2) and a Faradaic efficiency of〜100%,which is among one of the most efficient QDs-based photocathode systems coupling with Ni-substituted polyoxometalate catalyst for photoelectrochemical hydrogen generation.展开更多
基金supported by the key project of the National Natural Science Foundation of China (No. 61431001)Huawei Innovation Research Program, the 5G research program of China Mobile Research Institute (Grant No. [2015] 0615)+2 种基金the open research fund of National Mobile Communications Research Laboratory Southeast University (No.2017D02)Key Laboratory of Cognitive Radio and Information Processing, Ministry of Education (Guilin University of Electronic Technology)the Foundation of Beijing Engineering and Technology Center for Convergence Networks and Ubiquitous Services, and Keysight
文摘Massive multiple-input multiple-output(MIMO) system is capable of substantially improving the spectral efficiency as well as the capacity of wireless networks relying on equipping a large number of antenna elements at the base stations. However, the excessively high computational complexity of the signal detection in massive MIMO systems imposes a significant challenge for practical hardware implementations. In this paper, we propose a novel minimum mean square error(MMSE) signal detection using the accelerated overrelaxation(AOR) iterative method without complicated matrix inversion, which is capable of reducing the overall complexity of the classical MMSE algorithm by an order of magnitude. Simulation results show that the proposed AOR-based method can approach the conventional MMSE signal detection with significant complexity reduction.
基金the Earmarked Fund for China Agriculture Research System(No.CARS-46)。
文摘With Oreochromis niloticus as the object of study,glucose was added as a carbon source to promote the formation of the biological flocs for replacing part of the feed,and three gradients were set up,namely Group A(all feed),Group B(replacement of 10%feed)and Group C(replacement of 20%feed),so as to explore the effects of photosynthetic bacteria-enhanced biological flocs on tilapia growth and water environment conditions.Meanwhile,the Biolog-ECO technology was applied to study the changes of microbial carbon metabolism diversity in aquaculture water.The results showed that the utilization of microbial carbon sources under different feed replacement gradients increased with the extension of the culture time.The overall performance was in order of 10%replacement>all feed>20%feed replacement.A suitable replacement rate could not only enhance the overall utilization of carbon sources by water microorganisms,but also save culture costs.The principal component analysis showed that the carbon source metabolism of the water microbial communities under different feed replacement gradients was significantly different.Specifically,polysaccharides,esters and amino acids were the preferred carbon sources of water microbes,while the utilization of amines and acids was low.
基金supported by the National Natural Science Foundation of China (Nos. 21976198 and 21777175)the National Key Research and Development Program of China (No. 2018YFA0901200)。
文摘The rapid deactivation of cost-effective MnO_(2)-based catalysts in humid air limits their application in practice,and the identification of the role of water in an oxidation process is significant for developing water-resistant MnO_(2)-based catalysts.Here,CuMnO_(2)showed a20.3%HCHO conversion in 10 hr at room temperature in humid air with relative humidity of 40%,but deactivated in 3 hr in dry air.The excellent activity and stability of HCHO oxidation in humid air were attributed to the positive effect of H_(2)O on HCHO oxidation to the H_(2)O-HOCH_(2)OH supermolecule assemblies via hydrogen bonds formed on CuMnO_(2).H_(2)O-HOCH_(2)OH supermolecule assemblies tend to be oxidized to carbonate,which is further oxidized to CO_(2).Furthermore,CuMnO_(2)exhibited a much poorer activity of CO oxidation in humid air,but the CO conversion was still 100%in 10 hr in dry air.H_(2)O showed a competitive adsorption effect to CO on CuMnO_(2).CuMnO_(2)could be applied in HCHO elimination in humid air and CO elimination in dry air.
基金This work was supported by the Bill&Melinda Gates Foundation(Grant No.INV-049539)the Key Research and Development Program of Hainan Province(Grant No.ZDYF2020210)+1 种基金the Project of the National Social Science Fund of China(Grant No.20BGL264)the Shanghai Public Health System Construction Three-Year Action Plan(Grant No.GWVI-11.1-48)。
文摘Background Immunization is one of the most far-reaching and cost-effective strategies for promoting good health and saving lives.A complex immunization schedule,however,may be burdensome to parents and lead to reduced vaccine compliance and completion.Thus,it is critical to develop combination vaccines to reduce the number of injections and simplify the immunization schedule.This study aimed to investigate the current status of the pentavalent diphtheria-tetanus-acellular pertussis inactivated poliomyelitis andHaemophilus influenzae type B conjugate(DTaP-IPV/Hib)vaccination in Southern China as well as explore the factors in the general population associated with uptake and the differences between urban and rural populations.Methods A cross-sectional study was conducted with recently enrolled kindergarten students in Hainan Province between December 2022 and January 2023.The study employed a stratified multistage cluster random sampling method.Information regarding the demographic characteristics and factors that influence decisions were collected from the caregivers of children via an online questionnaire.Multivariate logistic regression was used to determine the factors associated with the status of DTap-IPV/Hib vaccinations.Results Of the 4818 valid responses,95.3%of children were aged 3-4 years,and 2856(59.3%)held ruralhukou.Coverage rates of the DTaP-IPV/Hib vaccine,from 1 to 4 doses,were 24.4%,20.7%,18.5%,and 16.0%,respectively.Caregivers who are concerned about vaccine efficacy[adjusted odds ratio(aOR)=1.53,95%confidence interval(CI):1.30-1.79],the manufacturer(aOR=2.05,95%CI:1.69-2.49),and a simple immunization schedule(aOR=1.26,95%CI:1.04-1.54)are factors associated with a higher likelihood of vaccinating children against DTaP-IPV/Hib.In addition,caregivers in urban areas showed more concern about the vaccine price(P=0.010)and immunization schedule(P=0.022)in regard to vaccinating children.Conclusions The DTaP-IPV/Hib vaccine coverage rate in Hainan Province remains low.Factors such as lower socioeconomic status,cultural beliefs,concerns about vaccine safety,and cost may hinder caregivers from vaccinating their children.Further measures,such as health education campaigns to raise knowledge and awareness,and encouragement of domestic vaccine innovation,which would reduce out-of-pocket costs,could be implemented to improve the coverage of DTap-IPV/Hib vaccination.
基金This work is financially supported by the National Natural Science Foundation of China(21975028,51673025)National Key Research and Development Program of China(2016YFBO700700)the start-up funding of BIT.
文摘of main observation and conclusion The heterojunction-type structure has shown significant merits in tuning the optical properties and carrier physics.Inspired by the excellent absorption capability of halide perovskite materials for visible light,a series of CsPbBr3/TiO2 heterojunction-type photocatalysts with various all-inorganic-perovskite/TiO2 ratios are successfully fabricated by the ligand-assisted reprecipitation(LARP)method.The heterojunction structure extends the light absorption of TiO2 with good chemical and structural stability.A Pb-O interaction at the CsPbBr3/TiO2 interface is observed by the XPS and confirmed by the TRPL showing improved interface carrier transport and stability.The heterojunction-type catalyst shows drastically enhanced photocatalytic activity towards the direct oxidation of toluene with 02 molecule,as an important reaction for organic chemical synthesis.The optimized sample shows an activity of 2356μmol·g^-1·h^-1 at 75℃,4 times of that of the naked CsPbBr3 nanocrystals,and 3 times of that of the bare TiO2.Based on the investigation with trapping agents,a reaction mechanism is hence proposed suggesting that the photo-generated hole may be involved in the rate-limiting step.This work demonstrates the potential of inorganic halide perovskite-based heterojunction structure for photocatalytic applications.
文摘The catalysts supported on LiA1508 （spinel） for vapor phase synthesis of dimethyl carbonate （DMC） from methyl nitrite （MN） have been studied. Their catalytic activities on supports prepared by different methods were evaluated in a continuous reactor. The samples were characterized by powder X-ray diffraction, N2 adsorption-desorption isotherms, fourier transform infrared spectroscopy and temperature-programmed reduction of H2. Li/A1 molar ratio and calcination temperature greatly influence the structure of crystalline phase of Li-AI-O oxides. Desirable LiAIsO8 （spinel） was formed at 800℃, while LiA1508 （primitive cube） formed at 900℃ is undesirable for the reaction. A high Li/A1 molar ratio, which was related with LiA102, also slowed the reaction rate. The electron transfer ability and the interaction with active component are the important properties of the spinel-based supports. The CuC12-PdC12/LiAIsO8 （spinel） with better electron transfer ability and low Pd2＋ reduction temperature exhibited a better catalytic ability.
基金support from the National Natural Science Foundation of China(Nos.21871025 and 21831001)the Recruitment Program of Global Experts(Young Talents)BIT Excellent Young Scholars Research Fund.
文摘In terms of photoelectrochemical(PEC)hydrogen evolution,substantial challenge still remains regarding the controllable fabrication of quantum dots(QDs)-sensitized photocathodes with enhanced visible-light absorption,efficient charge carrier separation,and directional migration at the electrode interface.In this work,the CdTe/CdSe QDs-sensitized photocathodes were delicately constructed on p-type NiO-coated indium tin oxide(ITO)electrodes by spin-coating approach.The resulting co-sensitized photocathode exhibits a favorable pseudo-Type Ⅱ energetic band alignment that combines the advantages of strong light absorption of constituent QDs as well as the effective and oriented charge separation and migration.Upon green LED light illumination,the photogenerated electrons could be effectively transferred to a tetra-nickel-substituted polyoxometalate catalyst for hydrogen production while photogenerated holes will be scavenged at the NiO/ITO electrode.Under minimally optimized conditions,the pseudo-Type Ⅱ CdTe/CdSe-sensrtized photocathode yields a photcx:urrent density of over 100 pA/cm^(2) and a Faradaic efficiency of〜100%,which is among one of the most efficient QDs-based photocathode systems coupling with Ni-substituted polyoxometalate catalyst for photoelectrochemical hydrogen generation.
