The advantage of using an available and abundant residual biomass, such as lignin, as a raw material for activated carbons is that it provides additional economical interest to the technical studies. In the current in...The advantage of using an available and abundant residual biomass, such as lignin, as a raw material for activated carbons is that it provides additional economical interest to the technical studies. In the current investigation, a more complete understanding of adsorption of Cr（VI） from aqueous systems onto HaPO4-acid activated lignin has been achieved via microcolumns, which were operated under various process conditions. The practice of using microcolumn is appropriate for defining the adsorption parameters and for screening a large number of poten- tial adsorbents. The effects of solution pH （2-8）, initial metal ion concentration （0.483-1.981 mmol.L-1）, flow rate （1.0-3.1 cm3-min-1）, ionic strength （0.01-0.30 mmol-L-1） and adsorbent mass （0.11 0.465 g） on Cr（VI） adsorption were studied by assessing the microcolmnn breakthrough curve. The microcolumn data were fitted by the Thomas model, the modified Dose model and the BDST model. As expected, the adsorption capacity increased with initial Cr（VI） concentration. High linear flow rates, pH values and ionic strength led to early breakthrough of Cr（VI）. The model constants obtained in this study can be used for the design of pilot scale adsorption process.展开更多
Significant field emission has been observed from thin(<1000Å)amorphous-carbon-nitride(a-CN)films.X-ray photoelectron spectroscopy,infrared spectrometry,and UV-visible optical absorption spectrometry have been...Significant field emission has been observed from thin(<1000Å)amorphous-carbon-nitride(a-CN)films.X-ray photoelectron spectroscopy,infrared spectrometry,and UV-visible optical absorption spectrometry have been used to characterize the films.The field emission properties of the thin film have been studied by using a transparent anode imaging system.It is proposed that this class of films should be studied as candidates of coating material for cold cathode emitter,in order for one to benefit from their very high thermal conductivity and super hardness.展开更多
We study the electronic structures of LiMn2O4 by x-ray and ultraviolet photoelectron spectroscopy （XPS, UPS） and resonant photoelectron spectroscopy （RPES）. XPS data suggest that the average oxidation state of Mn ...We study the electronic structures of LiMn2O4 by x-ray and ultraviolet photoelectron spectroscopy （XPS, UPS） and resonant photoelectron spectroscopy （RPES）. XPS data suggest that the average oxidation state of Mn ions is 3.55, probably due to the small amount of lithium oxides on the surface. UPS and RPES data imply that Mn ions are in a high spin state, and RPES results show strong Mn3d-O2p hybridization in the LiMn2O4 valence band.展开更多
CONSPECTUS:A super-repellent surface is a type of liquid-repellency material that allows for various liquid drops to bead up,roll off,or even bounce back.Known for its ability to remain dry,perform self-cleaning,and h...CONSPECTUS:A super-repellent surface is a type of liquid-repellency material that allows for various liquid drops to bead up,roll off,or even bounce back.Known for its ability to remain dry,perform self-cleaning,and have a low adhesion,a super-repellent surface presents great advantages in a number of applications.These include antifogging,anti-icing,oil/water separation,and fluid drag reduction.To fend off the liquids or drops,super-repellent surfaces combine the merits of surface chemistry and physical structure.By taking advantage of a low surface energy to prevent liquid from spreading,the super-repellent surfaces utilize the micronano structure to provide a framework that confines the solid−liquid interactions.Compared to beading up the drop of water,the repellence of liquid with low surface tension requires the subtle design of surface structure to resist the wetting of liquids.However,the inherent instabilities of the fragile micronano structure of super-repellent surfaces and solid−liquid interactions further make the fabrication of super-repellent surfaces complex to withstand dynamic environments(friction or wear)during application.In addition,the transparency and thermal stability of super-repellent surfaces are also the restrictive factors in some special application scenarios.To solve these challenges,durable super-repellent surfaces that can repel various liquids,possess robust mechanical and thermal stability,and show high transparency have been explored extensively in recent years.展开更多
This review outlines the developments and recent progress in metal-assisted chemical etching of silicon, summarizing a variety of fundamental and innovative processes and etching methods that form a wide range of nano...This review outlines the developments and recent progress in metal-assisted chemical etching of silicon, summarizing a variety of fundamental and innovative processes and etching methods that form a wide range of nanoscale silicon structures. The use of silicon as an anode for Li-ion batteries is also reviewed, where factors such as film thickness, doping, alloying, and their response to reversible lithiation processes are summarized and discussed with respect to battery cell performance. Recent advances in improving the performance of silicon-based anodes in Li-ion batteries are also discussed. The use of a variety of nanostructured silicon structures formed by many different methods as Li-ion battery anodes is outlined, focusing in particular on the influence of mass loading, core-shell structure, conductive additives, and other parameters. The influence of porosity, dopant type, and doping level on the electrochemical response and cell performance of the silicon anodes are detailed based on recent findings. Perspectives on the future of silicon and related materials, and their compositional and structural modifications for energy storage via several electrochemical mechanisms, are also provided.展开更多
An easy and effective solution based procedure for the synthesis of noble metal （both Au and Ag） tipped semiconductor nanomaterials is demonstrated where the metal precursors are taken in water and the semiconductor...An easy and effective solution based procedure for the synthesis of noble metal （both Au and Ag） tipped semiconductor nanomaterials is demonstrated where the metal precursors are taken in water and the semiconductors in organic medium, exploiting the phase transfer and reducing capability of suitably chosen ligands. The phase tranfer route is a generalised approach to form either Ag or Au tips on cadmium chalcogenide nanoparticles and nanorods. While multiple dots of noble metals are formed on the semiconductor nanomaterials initiall~ these coalesce into larger islands with time. The hybrids are characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, photoluminescence （PL）, ultraviolet-visible spectroscopy （UV-vis） and X-ray photoelectron spectroscopy （XPS）. A detailed FTIR analysis was also carried out to delineate the role of the ligands in the synthesis.展开更多
Based on the correspondence of the molecular orbital theory and valence bond theory to the description of chemical bonds,the ah imtio valence bond (VB) calculations of the low-lying states of diatomic molecules arc re...Based on the correspondence of the molecular orbital theory and valence bond theory to the description of chemical bonds,the ah imtio valence bond (VB) calculations of the low-lying states of diatomic molecules arc realized.The calculation results for the low-lying states of B2 show that the VB calculation has clear-cut physical significance,and its simulation of the behavior of the potential energy surface about the equilibrium position is superior to that of the molecular orbital theory.The valence bond calculation involving only a few bonded tableaus can correctly re fleet the effect of electronic correlation.展开更多
Despite extensive research on microplastics (MP) in marine environments, little is known about MP abundance and transport in terrestrial systems. There is, therefore, still little understanding of the main mechanisms ...Despite extensive research on microplastics (MP) in marine environments, little is known about MP abundance and transport in terrestrial systems. There is, therefore, still little understanding of the main mechanisms driving the substantial transport of MP across different environmental compartments. Storm events can transport MP beyond boundaries, such as from the land to groundwater or the ocean, as has already been discovered for organic carbon transport. Urban stormwater detention ponds are suitable environments to study the impact of stormwater on the environmental fate and transport of MP. Herein, we investigate the longitudinal and vertical distribution of MP within two detention ponds with different physical characteristics. Soil samples were collected at various locations and from multiple depths (surface and subsurface layers) for measuring MP concentrations using fluorescence microscopy. Our findings show that MP are retained more near the inlet of the ponds, and MP of larger sizes were found more abundantly near inlets than outlets. We also found that MP mass and sizes decrease from surface soil to subsurface soil. In the pond, where vegetation (grass root network) was more considerable, MP were found more evenly distributed along the depth. In terms of shape, the fragments were the most abundant MP shape.展开更多
文摘The advantage of using an available and abundant residual biomass, such as lignin, as a raw material for activated carbons is that it provides additional economical interest to the technical studies. In the current investigation, a more complete understanding of adsorption of Cr（VI） from aqueous systems onto HaPO4-acid activated lignin has been achieved via microcolumns, which were operated under various process conditions. The practice of using microcolumn is appropriate for defining the adsorption parameters and for screening a large number of poten- tial adsorbents. The effects of solution pH （2-8）, initial metal ion concentration （0.483-1.981 mmol.L-1）, flow rate （1.0-3.1 cm3-min-1）, ionic strength （0.01-0.30 mmol-L-1） and adsorbent mass （0.11 0.465 g） on Cr（VI） adsorption were studied by assessing the microcolmnn breakthrough curve. The microcolumn data were fitted by the Thomas model, the modified Dose model and the BDST model. As expected, the adsorption capacity increased with initial Cr（VI） concentration. High linear flow rates, pH values and ionic strength led to early breakthrough of Cr（VI）. The model constants obtained in this study can be used for the design of pilot scale adsorption process.
基金Supported by the National Natural Science Foundation for Outstanding Youth of China under Grant No.59525206the Higher Education Bureau of Guangdong Province.
文摘Significant field emission has been observed from thin(<1000Å)amorphous-carbon-nitride(a-CN)films.X-ray photoelectron spectroscopy,infrared spectrometry,and UV-visible optical absorption spectrometry have been used to characterize the films.The field emission properties of the thin film have been studied by using a transparent anode imaging system.It is proposed that this class of films should be studied as candidates of coating material for cold cathode emitter,in order for one to benefit from their very high thermal conductivity and super hardness.
文摘We study the electronic structures of LiMn2O4 by x-ray and ultraviolet photoelectron spectroscopy （XPS, UPS） and resonant photoelectron spectroscopy （RPES）. XPS data suggest that the average oxidation state of Mn ions is 3.55, probably due to the small amount of lithium oxides on the surface. UPS and RPES data imply that Mn ions are in a high spin state, and RPES results show strong Mn3d-O2p hybridization in the LiMn2O4 valence band.
基金We acknowledge funding support by the National Natural Science Foundation of China(22072014)the Fundamental Research Funds for the Central Universities(ZYGX2019J119)+2 种基金Max-Planck-Gesellschaft(Max Plank Partner Group UESTCMPIP)the Sichuan Science and Technology Program(2021JDRC0016)the Sichuan Outstanding Young Scholars Foundation(21JCQN0235).
文摘CONSPECTUS:A super-repellent surface is a type of liquid-repellency material that allows for various liquid drops to bead up,roll off,or even bounce back.Known for its ability to remain dry,perform self-cleaning,and have a low adhesion,a super-repellent surface presents great advantages in a number of applications.These include antifogging,anti-icing,oil/water separation,and fluid drag reduction.To fend off the liquids or drops,super-repellent surfaces combine the merits of surface chemistry and physical structure.By taking advantage of a low surface energy to prevent liquid from spreading,the super-repellent surfaces utilize the micronano structure to provide a framework that confines the solid−liquid interactions.Compared to beading up the drop of water,the repellence of liquid with low surface tension requires the subtle design of surface structure to resist the wetting of liquids.However,the inherent instabilities of the fragile micronano structure of super-repellent surfaces and solid−liquid interactions further make the fabrication of super-repellent surfaces complex to withstand dynamic environments(friction or wear)during application.In addition,the transparency and thermal stability of super-repellent surfaces are also the restrictive factors in some special application scenarios.To solve these challenges,durable super-repellent surfaces that can repel various liquids,possess robust mechanical and thermal stability,and show high transparency have been explored extensively in recent years.
基金WMS acknowledges support under the framework of the INSPIRE programme, funded by the Irish Government＇s Programme for Research in Third Level Institutions, Cycle 4, National Development Plan 2007-2013. COD acknowledges support from Science Foundation Ireland under Award No. 07/SK/ B1232a-STTF11 from the UCC Strategic Research Fund.
文摘This review outlines the developments and recent progress in metal-assisted chemical etching of silicon, summarizing a variety of fundamental and innovative processes and etching methods that form a wide range of nanoscale silicon structures. The use of silicon as an anode for Li-ion batteries is also reviewed, where factors such as film thickness, doping, alloying, and their response to reversible lithiation processes are summarized and discussed with respect to battery cell performance. Recent advances in improving the performance of silicon-based anodes in Li-ion batteries are also discussed. The use of a variety of nanostructured silicon structures formed by many different methods as Li-ion battery anodes is outlined, focusing in particular on the influence of mass loading, core-shell structure, conductive additives, and other parameters. The influence of porosity, dopant type, and doping level on the electrochemical response and cell performance of the silicon anodes are detailed based on recent findings. Perspectives on the future of silicon and related materials, and their compositional and structural modifications for energy storage via several electrochemical mechanisms, are also provided.
文摘An easy and effective solution based procedure for the synthesis of noble metal （both Au and Ag） tipped semiconductor nanomaterials is demonstrated where the metal precursors are taken in water and the semiconductors in organic medium, exploiting the phase transfer and reducing capability of suitably chosen ligands. The phase tranfer route is a generalised approach to form either Ag or Au tips on cadmium chalcogenide nanoparticles and nanorods. While multiple dots of noble metals are formed on the semiconductor nanomaterials initiall~ these coalesce into larger islands with time. The hybrids are characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, photoluminescence （PL）, ultraviolet-visible spectroscopy （UV-vis） and X-ray photoelectron spectroscopy （XPS）. A detailed FTIR analysis was also carried out to delineate the role of the ligands in the synthesis.
基金Project supported by the National Natural Science Foundation of China
文摘Based on the correspondence of the molecular orbital theory and valence bond theory to the description of chemical bonds,the ah imtio valence bond (VB) calculations of the low-lying states of diatomic molecules arc realized.The calculation results for the low-lying states of B2 show that the VB calculation has clear-cut physical significance,and its simulation of the behavior of the potential energy surface about the equilibrium position is superior to that of the molecular orbital theory.The valence bond calculation involving only a few bonded tableaus can correctly re fleet the effect of electronic correlation.
基金supported by Brown and Caldwell(USA).MMA,AB,and FJ were also partially supported by the United States Department of Agriculture,National Institute of Food and Agriculture(USDA/NIFA)(No.67019-31166-2020).
文摘Despite extensive research on microplastics (MP) in marine environments, little is known about MP abundance and transport in terrestrial systems. There is, therefore, still little understanding of the main mechanisms driving the substantial transport of MP across different environmental compartments. Storm events can transport MP beyond boundaries, such as from the land to groundwater or the ocean, as has already been discovered for organic carbon transport. Urban stormwater detention ponds are suitable environments to study the impact of stormwater on the environmental fate and transport of MP. Herein, we investigate the longitudinal and vertical distribution of MP within two detention ponds with different physical characteristics. Soil samples were collected at various locations and from multiple depths (surface and subsurface layers) for measuring MP concentrations using fluorescence microscopy. Our findings show that MP are retained more near the inlet of the ponds, and MP of larger sizes were found more abundantly near inlets than outlets. We also found that MP mass and sizes decrease from surface soil to subsurface soil. In the pond, where vegetation (grass root network) was more considerable, MP were found more evenly distributed along the depth. In terms of shape, the fragments were the most abundant MP shape.
