Layered manganese dioxide(δ-MnO_(2))is a promising cathode material for aqueous zinc-ion batteries(AZIBs)due to its high theoretical capacity,high operating voltage,and low cost.However,its practical application face...Layered manganese dioxide(δ-MnO_(2))is a promising cathode material for aqueous zinc-ion batteries(AZIBs)due to its high theoretical capacity,high operating voltage,and low cost.However,its practical application faces challenges,such as low electronic conductivity,sluggish diffusion kinetics,and severe dissolution of Mn^(2+).In this study,we developed a δ-MnO_(2) coated with a 2-methylimidazole(δ-MnO_(2)@2-ML)hybrid cathode.Density functional theory(DFT)calculations indicate that 2-ML can be integrated into δ-MnO_(2) through both pre-intercalation and surface coating,with thermodynamically favorable outcomes.This modification expands the interlayer spacing of δ-MnO_(2) and generates Mn-N bonds on the surface,enhancing Zn^(2+)accommodation and diffusion kinetics as well as stabilizing surface Mn sites.The experimentally prepared δ-MnO_(2)@2-ML cathode,as predicted by DFT,features both 2-ML pre-intercalation and surface coating,providing more zinc-ion insertion sites and improved structural stability.Furthermore,X-ray diffraction shows the expanded interlayer spacing,which effectively buffers local electrostatic interactions,leading to an enhanced Zn^(2+)diffusion rate.Consequently,the optimized cathode(δ-MnO_(2)@2-ML)presents improved electrochemical performance and stability,and the fabricated AZIBs exhibit a high specific capacity(309.5mAh/g at 0.1 A/g),superior multiplicative performance(137.6mAh/g at 1 A/g),and impressive capacity retention(80%after 1350 cycles at 1 A/g).These results surpass the performance of most manganese-based and vanadium-based cathode materials reported to date.This dual-modulation strategy,combining interlayer engineering and interface optimization,offers a straightforward and scalable approach,potentially advancing the commercial viability of low-cost,high-performance AZIBs.展开更多
在信号处理领域,传统的自适应滤波算法采用的固定步长会导致稳态误差和收敛速度无法同时兼顾。针对这个问题,对最小平均p范数(Least Mean p-norm,LMP)算法进行改进,提出了一种基于改进双曲正切(tanh)函数的变步长最小平均p范数算法。该...在信号处理领域,传统的自适应滤波算法采用的固定步长会导致稳态误差和收敛速度无法同时兼顾。针对这个问题,对最小平均p范数(Least Mean p-norm,LMP)算法进行改进,提出了一种基于改进双曲正切(tanh)函数的变步长最小平均p范数算法。该算法利用改进的tanh函数来调节步长,采用移动加权平均法构造变步长函数;同时引入了一个调节函数以进一步提升算法的性能。通过在海洋脉冲噪声干扰下进行仿真,实验表明,与已有的固定步长和变步长算法相比,改进的变步长LMP算法较好地兼顾系统的收敛速度和稳态误差;引入调节函数后的新算法在保证原有算法收敛速度的同时进一步降低了算法的稳态误差,从而兼顾了算法的收敛性和稳定性,具有较好的可行性。展开更多
To better characterize the optical properties of atmospheric aerosols, the multi-wavelength cavity ring-down aerosol extinction spectrometer(MCRD-AES) is developed and applied in this study. By using tunable light sou...To better characterize the optical properties of atmospheric aerosols, the multi-wavelength cavity ring-down aerosol extinction spectrometer(MCRD-AES) is developed and applied in this study. By using tunable light source and four parallel cavities, the MCRD-AES covers a wide and atmospherically relevant wavelength range from 360 to 663 nm. Four wavelengths(375 nm, 440 nm, 532 nm, and 620 nm) are particularly tested with ammonium sulfate and nigrosine. The refractive index values obtained from this study agree well with literature data. The stability and accuracy of the MCRD-AES are tested, and the minimum detectable extinction coefficient is 0.5 1/Mm. The high sensitivity, high precision, and wavelength changeable of MCRD-AES indicate its great application prospect in comprehensively quantifying the optical properties of atmospheric aerosols.展开更多
Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geolog...Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geological factors controlling the nature,condition,and distribution of earthquake-induced geohazards can be analyzed.Such insights facilitate earthquake disaster prediction and emergency response planning.The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events,examining ten earthquakes including the Wenchuan,Yushu,Lushan events,to elucidate the main control factors of seismic geohazard.The authors observed that seismic geohazard occurrence is usually affected by many factors,among which active nature of the seismogenic fault,seismic peak ground acceleration(PGA),topographic slope and geomorphic height differences,and distance from the fault zone and river system are the most important.Compared with strike-slip earthquakes,thrust earthquakes induce more high-altitude and high-speed remote landslides,which can cause great harm.Slopes of 0°–40°are prone to secondary seismic geohazards,which are mainly concentrated 0–6 km from the river system.Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area.The maximum seismic PGA and secondary seismic geohazard number are positively correlated,and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation,respectively.Through the research,the spatial distribution of seismic geohazards is predicted,providing a basis for the formulation of emergency response plans following disasters.展开更多
BACKGROUND The dysbiosis of the gut microbiome is evident in Crohn's disease(CD) compared with healthy controls(HC), although the alterations from active CD to remission after treatment are unclear.AIM To characte...BACKGROUND The dysbiosis of the gut microbiome is evident in Crohn's disease(CD) compared with healthy controls(HC), although the alterations from active CD to remission after treatment are unclear.AIM To characterize the mucosa-associated gut microbiota in patients with CD before and after the induction therapy.METHODS The basic information was collected from the subjects and the CD activity index(CDAI) was calculated in patients. A 16S rRNA sequencing approach was applied to determine the structures of microbial communities in mucosal samples including the terminal ileal, ascending colon, descending colon and rectum. The composition and function of mucosa-associated gut microbiota were compared between samples from the same cohort of patients before and after treatment.Differential taxa were identified to calculate the microbial dysbiosis index(MDI)and the correlation between MDI and CDAI was analyzed using Pearson correlation test. Predictive functional profiling of microbial communities was obtained with PICRUSt.RESULTS There were no significant differences in microbial richness among the four anatomical sites in individuals. Compared to active disease, the alpha diversity of CD in remission was increased towards the level of HC compared to the active stage. The principal coordinate analysis revealed that samples of active CD were clearly separated from those in remission, which clustered close to HC. Sixty-five genera were identified as differentially abundant between active and quiescent CD, with a loss of Fusobacterium and a gain of potential beneficial bacteria including Lactobacillus, Akkermansia, Roseburia, Ruminococcus and Lachnospira after the induction of remission. The combination of these taxa into a MDI showed a positive correlation with clinical disease severity and a negative correlation with species richness. The increased capacity for the inferred pathways including Lipopolysaccharide biosynthesis and Lipopolysaccharide biosynthesis proteins in patients before treatment negatively correlated with the abundance of Roseburia,Ruminococcus and Lachnospira.CONCLUSION The dysbiosis of mucosa-associated microbiota was associated with the disease phenotype and may become a potential diagnostic tool for the recurrence of disease.展开更多
The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot,which is an important component of atmosphericfine particle emissions.Herein,three-dimensionally ordered ma...The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot,which is an important component of atmosphericfine particle emissions.Herein,three-dimensionally ordered macroporous–mesoporous Ti_(x)Si+(1-x)O_(2)(3DOM-m Ti_(x)Si+(1-x)O_(2))and its supported MnO_(x)catalysts doped with different alkali/alkaline-earth metals(AMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)(A:Li,Na,K,Ru,Cs,Mg,Ca,Sr,Ba))were prepared by mesoporous template(P123)-assisted colloidal crystal template(CCT)and incipient wetness impregnation methods,respectively.Physicochemical characterizations of the catalysts were performed using scanning electron microscopy,X-ray diffraction,N_(2)adsorption–desorption,H_(2)temperature-programmed reduction,O_(2)temperature-programmed desorption,NO temperature-programmed oxidation,and Raman spectroscopy techniques;then,we evaluated their catalytic performances for the removal of diesel soot particles.The results show that the 3DOM-m Ti_(0.7)Si_(0.3)O_(2)supports exhibited a well-defined 3DOM-m nanostructure,and AMnO_(x)nanoparticles with 10–50 nm were evenly dispersed on the inner walls of the uniform macropores.In addition,the as-prepared catalysts exhibited good catalytic performance for soot combustion.Among the prepared catalysts,CsMnO_(x)/3DOM-m Ti_(0.7)Si_(0.3)O_(2)had the highest catalytic activity for soot combustion,with T10,T50,and T90(the temperatures corresponding to soot conversion rates of 10%,50%,and 90%)values of 285,355,and 393℃,respectively.The high catalytic activity of the CsMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)catalysts was attributed to their excellent low-temperature reducibility and homogeneous macroporous–mesoporous structure,as well as to the synergistic effects between Cs and Mn species and between CsMnO_(x)and the Ti_(0.7)Si_(0.3)O_(2)support.展开更多
In the 6th edition of the Chinese Space Trajectory Design Competition held in 2014, a near-Earth asteroid sample-return trajectory design problem was released, in which the motion of the spacecraft is modeled in multi...In the 6th edition of the Chinese Space Trajectory Design Competition held in 2014, a near-Earth asteroid sample-return trajectory design problem was released, in which the motion of the spacecraft is modeled in multi-body dynamics, considering the gravitational forces of the Sun, Earth, and Moon. It is proposed that an electric-propulsion spacecraft initially parking in a circular 200-kin-altitude low Earth orbit is expected to rendezvous with an asteroid and carry as much sample as possible back to the Earth in a 10-year time frame. The team from the Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences has reported a solution with an asteroid sample mass of 328 tons, which is ranked first in the competition. In this article, we will present our design and optimization methods, primarily including overall analysis, target selection, escape from and capture by the Earth-Moon system, and optimization of impulsive and low-thrust trajectories that are modeled in multi-body dynamics. The orbital resonance concept and lunar gravity assists are considered key techniques employed for trajectory design. The reported solution, preliminarily revealing the feasibility of returning a hundreds-of-tons asteroid or asteroid sample, envisions future space missions relating to near-Earth asteroid exploration.展开更多
基金supported by the the National Natural Science Foundation of China(52203303)the Shenzhen Science and Technology Program(SGDX20211123151002003 and GJHZ20220913142812025)+1 种基金the International Partnership Program of the Chinese Academy of Sciences(321GJHZ2023189FN)the SIAT International Joint Lab(E5G108).
文摘Layered manganese dioxide(δ-MnO_(2))is a promising cathode material for aqueous zinc-ion batteries(AZIBs)due to its high theoretical capacity,high operating voltage,and low cost.However,its practical application faces challenges,such as low electronic conductivity,sluggish diffusion kinetics,and severe dissolution of Mn^(2+).In this study,we developed a δ-MnO_(2) coated with a 2-methylimidazole(δ-MnO_(2)@2-ML)hybrid cathode.Density functional theory(DFT)calculations indicate that 2-ML can be integrated into δ-MnO_(2) through both pre-intercalation and surface coating,with thermodynamically favorable outcomes.This modification expands the interlayer spacing of δ-MnO_(2) and generates Mn-N bonds on the surface,enhancing Zn^(2+)accommodation and diffusion kinetics as well as stabilizing surface Mn sites.The experimentally prepared δ-MnO_(2)@2-ML cathode,as predicted by DFT,features both 2-ML pre-intercalation and surface coating,providing more zinc-ion insertion sites and improved structural stability.Furthermore,X-ray diffraction shows the expanded interlayer spacing,which effectively buffers local electrostatic interactions,leading to an enhanced Zn^(2+)diffusion rate.Consequently,the optimized cathode(δ-MnO_(2)@2-ML)presents improved electrochemical performance and stability,and the fabricated AZIBs exhibit a high specific capacity(309.5mAh/g at 0.1 A/g),superior multiplicative performance(137.6mAh/g at 1 A/g),and impressive capacity retention(80%after 1350 cycles at 1 A/g).These results surpass the performance of most manganese-based and vanadium-based cathode materials reported to date.This dual-modulation strategy,combining interlayer engineering and interface optimization,offers a straightforward and scalable approach,potentially advancing the commercial viability of low-cost,high-performance AZIBs.
文摘在信号处理领域,传统的自适应滤波算法采用的固定步长会导致稳态误差和收敛速度无法同时兼顾。针对这个问题,对最小平均p范数(Least Mean p-norm,LMP)算法进行改进,提出了一种基于改进双曲正切(tanh)函数的变步长最小平均p范数算法。该算法利用改进的tanh函数来调节步长,采用移动加权平均法构造变步长函数;同时引入了一个调节函数以进一步提升算法的性能。通过在海洋脉冲噪声干扰下进行仿真,实验表明,与已有的固定步长和变步长算法相比,改进的变步长LMP算法较好地兼顾系统的收敛速度和稳态误差;引入调节函数后的新算法在保证原有算法收敛速度的同时进一步降低了算法的稳态误差,从而兼顾了算法的收敛性和稳定性,具有较好的可行性。
基金supported by the National Natural Science Foundation of China (No.41227805)the National Key Research and Development Program of China (No.2016YFC0202704)
文摘To better characterize the optical properties of atmospheric aerosols, the multi-wavelength cavity ring-down aerosol extinction spectrometer(MCRD-AES) is developed and applied in this study. By using tunable light source and four parallel cavities, the MCRD-AES covers a wide and atmospherically relevant wavelength range from 360 to 663 nm. Four wavelengths(375 nm, 440 nm, 532 nm, and 620 nm) are particularly tested with ammonium sulfate and nigrosine. The refractive index values obtained from this study agree well with literature data. The stability and accuracy of the MCRD-AES are tested, and the minimum detectable extinction coefficient is 0.5 1/Mm. The high sensitivity, high precision, and wavelength changeable of MCRD-AES indicate its great application prospect in comprehensively quantifying the optical properties of atmospheric aerosols.
基金supported by the National Natural Science Foundation of China(41977258)the National Key Research and Development Program of China(2017YFC1501005 and 2018YFC1504704)。
文摘Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geological factors controlling the nature,condition,and distribution of earthquake-induced geohazards can be analyzed.Such insights facilitate earthquake disaster prediction and emergency response planning.The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events,examining ten earthquakes including the Wenchuan,Yushu,Lushan events,to elucidate the main control factors of seismic geohazard.The authors observed that seismic geohazard occurrence is usually affected by many factors,among which active nature of the seismogenic fault,seismic peak ground acceleration(PGA),topographic slope and geomorphic height differences,and distance from the fault zone and river system are the most important.Compared with strike-slip earthquakes,thrust earthquakes induce more high-altitude and high-speed remote landslides,which can cause great harm.Slopes of 0°–40°are prone to secondary seismic geohazards,which are mainly concentrated 0–6 km from the river system.Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area.The maximum seismic PGA and secondary seismic geohazard number are positively correlated,and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation,respectively.Through the research,the spatial distribution of seismic geohazards is predicted,providing a basis for the formulation of emergency response plans following disasters.
基金the National Natural Science Foundation of China,No.81660101 and No.81860106the Special Scientific Research Fund of Public Welfare Profession of National Health and Family Planning Commission,No.201502026the Graduate Innovation Fund of Nanchang University,No.CX2017251
文摘BACKGROUND The dysbiosis of the gut microbiome is evident in Crohn's disease(CD) compared with healthy controls(HC), although the alterations from active CD to remission after treatment are unclear.AIM To characterize the mucosa-associated gut microbiota in patients with CD before and after the induction therapy.METHODS The basic information was collected from the subjects and the CD activity index(CDAI) was calculated in patients. A 16S rRNA sequencing approach was applied to determine the structures of microbial communities in mucosal samples including the terminal ileal, ascending colon, descending colon and rectum. The composition and function of mucosa-associated gut microbiota were compared between samples from the same cohort of patients before and after treatment.Differential taxa were identified to calculate the microbial dysbiosis index(MDI)and the correlation between MDI and CDAI was analyzed using Pearson correlation test. Predictive functional profiling of microbial communities was obtained with PICRUSt.RESULTS There were no significant differences in microbial richness among the four anatomical sites in individuals. Compared to active disease, the alpha diversity of CD in remission was increased towards the level of HC compared to the active stage. The principal coordinate analysis revealed that samples of active CD were clearly separated from those in remission, which clustered close to HC. Sixty-five genera were identified as differentially abundant between active and quiescent CD, with a loss of Fusobacterium and a gain of potential beneficial bacteria including Lactobacillus, Akkermansia, Roseburia, Ruminococcus and Lachnospira after the induction of remission. The combination of these taxa into a MDI showed a positive correlation with clinical disease severity and a negative correlation with species richness. The increased capacity for the inferred pathways including Lipopolysaccharide biosynthesis and Lipopolysaccharide biosynthesis proteins in patients before treatment negatively correlated with the abundance of Roseburia,Ruminococcus and Lachnospira.CONCLUSION The dysbiosis of mucosa-associated microbiota was associated with the disease phenotype and may become a potential diagnostic tool for the recurrence of disease.
基金supported by Key Research and Development Program of Ministry of Science and Technology of the People’s Republic of China(MOST)(No.2017YFE0131200)for collaboration between China and PolandNational Nature Science Foundation of China(NSFC)(Nos.22072095,U1908204,21761162016)+3 种基金General Projects of Liaoning Province Natural Fund(No.2019-MS-284)National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2018A04)University level innovation team of Shenyang Normal University,Major Incubation Program of Shenyang Normal University(No.ZD201901)supported by the Research Grants Council(RGC)of Hong Kong through NSFC/RGC Joint Research Scheme(No.N_CUHK451/17)。
文摘The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot,which is an important component of atmosphericfine particle emissions.Herein,three-dimensionally ordered macroporous–mesoporous Ti_(x)Si+(1-x)O_(2)(3DOM-m Ti_(x)Si+(1-x)O_(2))and its supported MnO_(x)catalysts doped with different alkali/alkaline-earth metals(AMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)(A:Li,Na,K,Ru,Cs,Mg,Ca,Sr,Ba))were prepared by mesoporous template(P123)-assisted colloidal crystal template(CCT)and incipient wetness impregnation methods,respectively.Physicochemical characterizations of the catalysts were performed using scanning electron microscopy,X-ray diffraction,N_(2)adsorption–desorption,H_(2)temperature-programmed reduction,O_(2)temperature-programmed desorption,NO temperature-programmed oxidation,and Raman spectroscopy techniques;then,we evaluated their catalytic performances for the removal of diesel soot particles.The results show that the 3DOM-m Ti_(0.7)Si_(0.3)O_(2)supports exhibited a well-defined 3DOM-m nanostructure,and AMnO_(x)nanoparticles with 10–50 nm were evenly dispersed on the inner walls of the uniform macropores.In addition,the as-prepared catalysts exhibited good catalytic performance for soot combustion.Among the prepared catalysts,CsMnO_(x)/3DOM-m Ti_(0.7)Si_(0.3)O_(2)had the highest catalytic activity for soot combustion,with T10,T50,and T90(the temperatures corresponding to soot conversion rates of 10%,50%,and 90%)values of 285,355,and 393℃,respectively.The high catalytic activity of the CsMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)catalysts was attributed to their excellent low-temperature reducibility and homogeneous macroporous–mesoporous structure,as well as to the synergistic effects between Cs and Mn species and between CsMnO_(x)and the Ti_(0.7)Si_(0.3)O_(2)support.
基金supported by the National Natural Science Foundation of China(Grant11372311)the grant from the State key Laboratory of Astronautic Dynamics(2014-ADL-DW0201)
文摘In the 6th edition of the Chinese Space Trajectory Design Competition held in 2014, a near-Earth asteroid sample-return trajectory design problem was released, in which the motion of the spacecraft is modeled in multi-body dynamics, considering the gravitational forces of the Sun, Earth, and Moon. It is proposed that an electric-propulsion spacecraft initially parking in a circular 200-kin-altitude low Earth orbit is expected to rendezvous with an asteroid and carry as much sample as possible back to the Earth in a 10-year time frame. The team from the Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences has reported a solution with an asteroid sample mass of 328 tons, which is ranked first in the competition. In this article, we will present our design and optimization methods, primarily including overall analysis, target selection, escape from and capture by the Earth-Moon system, and optimization of impulsive and low-thrust trajectories that are modeled in multi-body dynamics. The orbital resonance concept and lunar gravity assists are considered key techniques employed for trajectory design. The reported solution, preliminarily revealing the feasibility of returning a hundreds-of-tons asteroid or asteroid sample, envisions future space missions relating to near-Earth asteroid exploration.
