During the initial impoundment period of a canyon-shaped reservoir,the water body fluctuated violently regarding water level,hydrological condition,and thermal stratification.These variations may alter the structure o...During the initial impoundment period of a canyon-shaped reservoir,the water body fluctuated violently regarding water level,hydrological condition,and thermal stratification.These variations may alter the structure of phytoplankton community,resulting in algal blooms and seriously threatening the ecological security of the reservoir.It is of great significance to understand the continuous changes of phytoplankton in the initial impoundment period for the protection of reservoir water quality.Therefore,a two-year in-situ monitoring study was conducted on water quality and phytoplankton in a representative canyonshaped reservoir named Sanhekou and the interannual changes of phytoplankton community and its response to environmental changes during the initial impoundment period were discussed at taxonomic versus functional classification levels.The results showed that the total nitrogen and permanganate index levels were relatively high in the first year due to rapid water storage and heavy rainfall input,and the more stable hydrological conditions in the second year promoted the increase of algae density and the transformation of community,and the proportion of cyanobacteria increased significantly.The succession order of phytoplankton in the first year of the initial impoundment periodwas Chlorophyta-Bacillariophyta-Chlorophyta,or J/F/X1-P/MP/W1-A/X1/MP,respectively.And the succession order in the second year was Cyanobacteria/Chlorophyta-Bacillariophyta-Chlorophyta,or L_(M)/G/P-P/A/X1-X1/J/G.Water temperature,relativewater column stability,mixing depth,and pHwere crucial factors affecting phytoplankton community succession.This study revealed the interannual succession law and driving factors of phytoplankton in the initial impoundment period and provided an important reference for the operation management and ecological protection of canyon-shaped reservoirs.展开更多
Lithium-ion capacitors(LICs)combine the high power dens-ity of electrical double-layer capacitors with the high energy density of lithium-ion batteries.However,they face practical limitations due to the narrow operati...Lithium-ion capacitors(LICs)combine the high power dens-ity of electrical double-layer capacitors with the high energy density of lithium-ion batteries.However,they face practical limitations due to the narrow operating voltage window of their activated carbon(AC)cathodes.We report a scalable thermal treatment strategy to develop high-voltage-tolerant AC cathodes.Through controlled thermal treatment of commer-cial activated carbon(Raw-AC)under a H_(2)/Ar atmosphere at 400-800℃,the targeted reduction of degradation-prone functional groups can be achieved while preserving the critical pore structure and increasing graph-itic microcrystalline ordering.The AC treated at 400℃(HAC-400)had a significant increase in specific capacity(96.0 vs.75.1 mAh/g at 0.05 A/g)and better rate capability(61.1 vs.36.1 mAh/g at 5 A/g)in half-cell LICs,along with an 83.5%capacity retention over 7400 cycles within an extended voltage range of 2.0-4.2 V in full-cell LICs.Scalability was demonstrated by a 120 g batch production,enabling fabrication of pouch-type LICs with commercial hard carbon anodes that delivered a higher energy density of 28.3 Wh/kg at 1 C,and a peak power density of 12.1 kW/kg compared to devices using raw AC.This simple,industry-compatible approach may be used for producing ad-vanced cathode materials for practical high-performance LICs.展开更多
As a new electrochemical technology,capacitive deionization(CDI)has been increasingly applied in environmental water treatment and seawater desalination.In this study,functional groups modified porous hollow carbon(HC...As a new electrochemical technology,capacitive deionization(CDI)has been increasingly applied in environmental water treatment and seawater desalination.In this study,functional groups modified porous hollow carbon(HC)were synthesized as CDI electrode material for removing Na^(+)and Cl^(−)in salty water.Results showed that the average diameter of HC was approximately 180 nm,and the infrared spectrum showed that its surface was successfully modified with sulfonic and amino groups,respectively.The sulfonic acid functionalized HC(HC-S)showed better electrochemical and desalting performance than the amino-functionalized HC(HC–N),with a maximum Faradic capacity of 287.4 F/g and an adsorptive capacity of 112.97 mg/g for NaCl.Additionally,92.63%capacity retention after 100 adsorption/desorption cycles demonstrates the excellent stability of HC-S.The main findings prove that HC-S is viable as an electrodematerial for desalination by high-performance CDI applications.展开更多
Taking the Lower Silurian Longmaxi Formation shale in the Sichuan Basin as an example,this study employs atomic force microscopy-based infrared(AFM-IR)spectroscopy to analyze the submicron-scale molecular functional g...Taking the Lower Silurian Longmaxi Formation shale in the Sichuan Basin as an example,this study employs atomic force microscopy-based infrared(AFM-IR)spectroscopy to analyze the submicron-scale molecular functional groups of different types and occurrences of organic matter.Combined with the quantitative evaluation of pore development via scanning electron microscopy(SEM),the response of organic pore formation and evolution mechanisms to chemical composition and structural evolution of organic matter in overmature marine shale is investigated.The results indicate that the AFM-IR spectra of graptolite periderms and pyrobitumen in shale are dominated by the stretching vibrations of conjugated C=C bonds in aromatic compounds at approximately 1600 cm-1,with weak absorption peaks near 1375,1450 and 1720 cm-1,corresponding to aliphatic chains and carbonyl/carboxyl functional groups.Overall,the AFM-IR structural indices(A and C factors)of organic matter show a strong correlation with visible porosity in shales of equivalent maturity.Lower A and C factor values correlate with enhanced development of organic pores,which is associated with the detachment of more aliphatic chains and oxygen-containing functional groups during thermal evolution.Pyrobitumen-clay mineral composites generally exhibit superior pore development,likely attributable to clay mineral dehydration participating in hydrocarbon generation reactions that promote the removal of more functional groups.Additionally,hydrocarbon generation within organic-clay composites during high-over mature stages may induce volumetric expansion,resulting in microfracturing and hydrocarbon expulsion.The associated higher hydrocarbon expulsion rates promote the formation of larger pores and fracture-shaped pores along the flake-shaped clay minerals.This study highlights that the research of submicron-scale molecular functional groups provides a deeper understanding of organic matter evolution and pores development mechanisms in overmature shales,thereby offering critical theoretical parameters for reservoir evaluation in shale oil and gas exploration.展开更多
Difunctionalization of unsaturated hydrocarbons is a pivotal synthetic strategy enabling the conversion of alkenes and alkynes into high value-added compounds.It allows for the introduction of two functional groups in...Difunctionalization of unsaturated hydrocarbons is a pivotal synthetic strategy enabling the conversion of alkenes and alkynes into high value-added compounds.It allows for the introduction of two functional groups into the unsaturated bond in a single step,facilitating the efficient construction of complex molecular architectures,which has been widely utilized in material chemistry,pharmaceutical and fine chemical synthesis.Recently,significant progress has been made via free radical-mediated difunctionalization due to the extensive application of photocatalysis.However,highly selective difunc-tionalization reactions still remain challenging.The research progress of selective difunctionalization of unsaturated hydro-carbons using a free radical addition/functional group migration strategy over the past decade is summarized,and synthetic strategies and key reaction steps are systematically elaborated.展开更多
The activated carbon with high surface area was prepared by KOH activation.It was further modified by H2SO4 and HNO3 to introduce more surface functional groups.The pore structure of the activated carbons before and a...The activated carbon with high surface area was prepared by KOH activation.It was further modified by H2SO4 and HNO3 to introduce more surface functional groups.The pore structure of the activated carbons before and after modification was analyzed based on the nitrogen adsorption isotherms.The morphology of those activated carbons was characterized using scanning electronic microscopy （SEM）.The surface functional groups were determined by Fourier transform infrared spectroscopy （FTIR）.The quantity of those groups was measured by the Boehm titration method.Cr（VI） removal by the activated carbons from aqueous solution was investigated at different pH values.The results show that compared with H2SO4,HNO3 destructs the original pore of the activated carbon more seriously and induces more acidic surface functional groups on the activated carbon.The pH value of the solution plays a key role in the Cr（VI） removal.The ability of reducing Cr（VI） to Cr（III） by the activated carbons is relative to the acidic surface functional groups.At higher pH values,the Cr（VI） removal ratio is improved by increasing the acidic surface functional groups of the activated carbons.At lower pH values,however,the acidic surface functional groups almost have no effect on the Cr（VI） removal by the activated carbon from aqueous solution.展开更多
Graphene quantum dots(GQDs) possess great potential in various applications due to their superior physicochemical properties and wide array of available surface modifications.However, the toxicity of GQDs has not been...Graphene quantum dots(GQDs) possess great potential in various applications due to their superior physicochemical properties and wide array of available surface modifications.However, the toxicity of GQDs has not been systematically assessed, thus hindered their further development; especially, the risk of surface modifications of GQDs is largely unknown. In this study, we employed a lung carcinoma A549 cells as the model to investigate the cytotoxicity and autophagy induction of three types GQDs, including cGQDs(COOH-GQDs), hGQDs(OH-GQDs), and aGQDs(NH_2-GQDs). The results showed hGQDs was the most toxic, as significant cell death was induced at the concentration of 100 μg/mL,determining by WST-1 assay as well as Annexin-V-FITC/PI apoptosis analysis, whereas cGQDs and aGQDs were non-cytotoxic within the measured concentration. Autophagy detection was performed by TEM examination, LC3 fluorescence tracking, and Westernblot. Both aGQDs and hGQDs induced cellular autophagy to various degrees except for cGQDs. Further analysis on autophagy pathways indicated all GQDs significantly activated p-p38 MAPK; p-ERK1/2 was inhibited by aGQDs and hGQDs but activated by c GQDs. p-JNK was inhibited by aGQDs and c GQDs, while activated by hGQDs. Simultaneously, Akt was activated by hGQDs but inhibited by aGQDs. Inhibition of autophagy by 3-MA significantly increased the cytotoxicity of GQDs, suggesting that autophagy played a protective role against the toxicity of GQDs. In conclusion, c GQDs showed excellent biocompatibility and may be considered for biological applications. Autophagy induction may be included in the health risk assessment of GQDs as it reflects the stress status which may eventually lead to diseases.展开更多
The transition metal-catalyzed C–H activation have been considered as increasingly useful approach for installing new functional groups onto organic small molecules due to their high step-and atom-economy,the abundan...The transition metal-catalyzed C–H activation have been considered as increasingly useful approach for installing new functional groups onto organic small molecules due to their high step-and atom-economy,the abundance of hydrocarbon compounds,and the potential for late-stage functionalization of complex organic molecules.The ortho-and meta-C-H activation and functionalization of aromatic compounds have been widely explored in recent years,however the distal para-C-H activation and functionalization has remained a significant challenge because of the difficulty in forming energetically favorable metallacyclic transition states.The utilization of appropriate directing groups or templates as well as the meticulous design of catalysts and ligands has proven to be effective in transition-metal-catalyzed remote para-C-H bonds activation and functionalization of aromatic compounds.This review aims to summarize the strategies for controlling para-selective C–H functionalization using the directing group,template engineering,and catalyst/ligand design under transition metals catalysis in recent years.展开更多
Amyloid-like proteins are critical for interfacial adhesion across various marine organisms and bacteria.However,the specific contributions of different functional residues remain unclear.Herein,we introduce an approa...Amyloid-like proteins are critical for interfacial adhesion across various marine organisms and bacteria.However,the specific contributions of different functional residues remain unclear.Herein,we introduce an approach to deconstruct and mimic these residues using synthetic homopolymers and random copolymers with phenyl,amino,carboxyl,and hydroxyl functional groups using reversible addition-fragmentation chain transfer(RAFT)polymerization.The resulting polymers,designed with comparable molecular weights(M_(n):10–20 kDa)and narrow dispersities(PDI<1.3),mimic the diverse surface chemistry of amyloid-like proteins,enabling systematic investigation of their adhesive properties.The interfacial adhesion forces of different polymer films were quantified using atomic force microscopy(AFM)with a colloidal probe.Remarkably copolymers with multiple functional groups demonstrated significantly enhanced adhesion compared to homopolymers,a trend corroborated by macroscopic shear strength and stability tests.These results highlight that the synergistic effects of multiple functional groups are crucial for achieving universal interfacial adhesion of macromolecules,offering insights into protein adhesion mechanisms,and guiding polymer-based interfacial modifications.展开更多
The functional groups on graphene sheets surface affect their dispersion and interfacial adhesion in polymer matrix. We compared the mechanical property of polymethymethacrylate（PMMA） microcellular foams reinforced ...The functional groups on graphene sheets surface affect their dispersion and interfacial adhesion in polymer matrix. We compared the mechanical property of polymethymethacrylate（PMMA） microcellular foams reinforced with graphene oxide（GO） and reduced graphene oxide（RGO） to investigate this influence of functional groups. RGO sheets were fabricated by solvent thermal reduction in DMF medium. UV-Vis, FT-IR and XPS analyses indicate the difference of oxygen-containing groups on GO and RGO sheets surface. The observation of SEM illustrates that the addition of a smaller number of GO or RGO sheets causes a fine cellular structure of PMMA foams with a higher cell density(about 1011 cells/cm3) and smaller cell sizes（about 1-2 μm） owing to their remarkable heterogeneous nucleation effect. Compared to GO reinforced foams, the RGO/PMMA foams own lower cell density and bigger cell size in their microstructure, and their compressive strength is lower even when the reinforcement contents are the same and the foam bulk density is higher. These results indicate that the oxygen-containing groups on GO sheets’ surface are beneficial to adhere CO2 to realize a larger nucleation rate, and their strong interaction with PMMA matrix improves the mechanical property of PMMA foams.展开更多
Variations in the fractions of biomass allocated to functional components are widely considered as plant responses to resource availability for grassland plants. Observations indicated shoots isometrically relates to ...Variations in the fractions of biomass allocated to functional components are widely considered as plant responses to resource availability for grassland plants. Observations indicated shoots isometrically relates to roots at the community level but allometrically at the species level in Tibetan alpine grasslands. These differences may result from the specific complementarity of functional groups between functional components, such as leaf, root, stem and reproductive organ. To test the component complementary responses to regional moisture variation, we conducted a multi-site transect survey to measure plant individual size and component biomass fractions of common species belonging to the functional groups： forbs, grasses, legumes and sedges on the Northern Tibetan Plateau in peak growing season in 2010. Along the mean annual precipitation （MAP） gradient, we sampled 7o species, in which 2o are in alpine meadows, 20 in alpine steppes, 15 in alpine desert-steppes and 15 in alpine deserts, respectively. Our results showed that the size of alpine plants is small with individual biomass mostly lower than 1.0 g. Plants keep relative conservative component individual responses moisture functional fractions across alpine grasslands at the level. However, the complementary between functional components to variations specifically differ among groups. These results indicate that functional group diversity may be an effective tool for scaling biomass allocation patterns from individual up to community level. Therefore, it is necessary andvaluable to perform intensive and systematic studies on identification and differentiation the influences of compositional changes in functional groups on ecosystem primary services and processes.展开更多
The adsorption behaviors and dispersing properties of polycarboxylate superplasticizer(PCE) with different functional groups were systematically analyzed to reveal the theory and methods of modifying PCE molecular str...The adsorption behaviors and dispersing properties of polycarboxylate superplasticizer(PCE) with different functional groups were systematically analyzed to reveal the theory and methods of modifying PCE molecular structures and regulating PCE performances. By substituting carboxylic groups with sulfonic groups, ester groups or acylamino groups, respectively, modified PCEs with different functional groups were synthesized. Results show that introducing low amount of ester groups or sulfonic groups into the PCE molecules has no negative effects on the fluidity of cement paste, while introducing acylamino groups into PCE molecules significantly weakens the fluidity of cement paste. At low amount(when the molar ratio of sodium methallyl sulfonate to TPEG is lower than 0.4), the rapid adsorption of sulfonic groups onto the cement particles contributes to the high dispersing performance of the sulfonic group modified PCEs. When the substitution ratio of acrylic acid by sulfonic acid is higher than 0.4, the viscosity and the yield stress of cement paste increases sharply. Redundant sulfonic groups lead to the excessive charge density of the PCE, which contributes to the inhomogeneous adsorption on the cement grains and hence results in the decline of the dispersing performance. Substitution of carboxylic group by acylamino group or ester group slightly changes the viscosity as well as the yield stress of cement paste. Introducing sulfonic group into PCE molecule improves the adsorption behavior of PCEs, while introducing ester group or acylamino group into PCE depresses the adsorption properties.展开更多
The relationship between trace elements in coal and organic functional groups of coal, also some of aromatic structure, was investigated by using curve fitting of infrared spectra. Cluster analysis was also performed ...The relationship between trace elements in coal and organic functional groups of coal, also some of aromatic structure, was investigated by using curve fitting of infrared spectra. Cluster analysis was also performed according to the degree of affinity of organic groups to the trace elements. The results show that there is a possibility that trace elements, especially LREE, were bound to peripheral organic functional groups of middle rank coal macromolecule. The most possible functional group that binds trace element is the hydroxyl, and to the less degree, the asymmetric -CH3 and 〉CH2 stretching, -CH3 stretching, etc. The degree of affinity of trace elements to different functional groups varies. The tendency obeys the natural structural changing law of trace elements-- the periodic law. The deviation of some trace elements from this regular trend is attributed to the deviation of intrinsic ＂confusion degree＂ （conventional molar entropy） of the matter system of coal basin, which is affected by the inner and outer factors during the evolution.展开更多
The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao,Shandong Province,China,during...The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao,Shandong Province,China,during a six-month study period （a complete shrimp-culture cycle） from May to October 2002.The results reveal that： （1） the protist communities represented five trophic and functional groups of the species identified,about 60% were photoautotrophs,20% algivores,12% bacterivores,5% raptors and about 3% non-selectives;（2） the photoautotrophs,algivores and bacterivores were the primary contributors to the changes in the protist communities in short temporal scales,the succession of dominance typically being bacterivores→photoautotrophs→algivores,with the raptors dominating the protist communities in a single sample （early June）;（3） the photoautotrophs and non-selectives were the primary contributors to the peak of protist abundance in early October whereas the photoautotrophs,bacterivores,raptors and non-selectives mainly gave rise to two bimodal peaks of biomass in July and October respectively;（4） five functional groups of protist communities represented significant correlations with water nutrients （i.e.,NH 3-N,NO 3-N,and PO 4 ）,either alone or in combination with temperature,of which algivores and raptors were strongly correlated with phosphate and the concentration of Chl a,while bacterivores were strongly related to nitrogen and the concentration of bacteria.These findings confirm that planktonic protists are potentially useful bioindicators of water quality in the semi-enclosed mariculture system.展开更多
Historical data indicate that the dominance of submerged plants in Dianchi Lake in the 1960 s was characterized by low algal density with dominance of non-toxic group J（Scenedesmus,Pediastrum,etc.）. The removal of s...Historical data indicate that the dominance of submerged plants in Dianchi Lake in the 1960 s was characterized by low algal density with dominance of non-toxic group J（Scenedesmus,Pediastrum,etc.）. The removal of submerged plants,which began in the 1970 s,resulted in the expansion of bloom-forming Microcystis（group M）. Laboratory experiments suggested that Microcystis aeruginosa was inclined to grow and develop at elevated temperatures. The growth of Scenedesmus obliquus was slower than that of co-cultivated M. aeruginosa in the absence of Ceratophyllum demersum,especially at higher temperatures. The existence of submerged plant C. demersum could inhibit the growth of the harmful algae M. aeruginosa and this inhibitory effect by C. demersum was enhanced with an increase in temperature. Instead,with C. demersum,the growth of S. obliquus was not inhibited,but the co-cultivated M. aeruginosa was eliminated in a short time. Combined with the historical data and laboratory experiments,it was indicated that the submerged plants might play important roles in the dominance of the non-toxic group J in the historical succession. Consequently,the introduction of the submerged plant such as C. demersum might alter the dominant phytoplankton functional groups from M to J and benefit the restoration of the eutrophic lake.展开更多
A series of new chelating resins with incorporating heterocyclic functional groups： pyridine, thiadizole, benzothizole into macroporous chloromethylated polystyrene were synthesized via hydrophilic spacer arm of poly...A series of new chelating resins with incorporating heterocyclic functional groups： pyridine, thiadizole, benzothizole into macroporous chloromethylated polystyrene were synthesized via hydrophilic spacer arm of polyethylene glycol containing sulfur. These chelating resins were found to show high adsorption capacities for Ag^＋, Hg^2＋, Au^3＋ and Pd^2＋, and the presence of spacer arm can enhance adsorption ability due to increase the hydrophilicity of the chelating resins.展开更多
Reservoirs are an important water source in many densely populated areas in southwest China.Phytoplankton play an essential role in maintaining the structure and function of reservoir ecosystems.Understanding the succ...Reservoirs are an important water source in many densely populated areas in southwest China.Phytoplankton play an essential role in maintaining the structure and function of reservoir ecosystems.Understanding the succession in phytoplankton communities and the factors driving it are essential for eff ective water quality management in drinking water reservoirs.In this study,water samples were collected monthly at the surface layers from March 2016 to December 2019 in Hongfeng Reservoir,southwest China.The relationship between functional group succession was analyzed based on nonmetric multidimensional scaling analysis(NMDS),redundancy analysis(RDA),succession rate,and other analysis methods.The results showed distinct shifts in the community structure of phytoplankton functional groups within study period.The Cyclotella sp.was dominant in 2016 and 2017,and Pseudanabaena limnetica was the dominant group in 2018 and 2019.It appears that the phytoplankton composition and biomass are closely related to the water temperature and nutrient status in this reservoir.The results clearly showed that the permanganate index(COD_(Mn))was the key factor of dramatic phytoplankton functional group succession,and the change in succession rates was closely caused by total nitrogen concentration(TN).Therefore,the succession pattern and key factors of Hongfeng Reservoir revealed in this study were important guidance for the management of drinking water reservoirs in southwest China.A reasonable limit on exogenous nutrient input should be a priority,especially in high water temperature period.展开更多
The three-dimensional（3D） visualization of the functional bundles in the peripheral nerve provides direct and detailed intraneural spatial information. It is useful for selecting suitable surgical methods to repair ...The three-dimensional（3D） visualization of the functional bundles in the peripheral nerve provides direct and detailed intraneural spatial information. It is useful for selecting suitable surgical methods to repair nerve defects and in optimizing the construction of tissue-engineered nerve grafts. However, there remain major technical hurdles in obtaining, registering and interpreting 2D images, as well as in establishing 3D models. Moreover, the 3D models are plagued by poor accuracy and lack of detail and cannot completely reflect the stereoscopic microstructure inside the nerve. To explore and help resolve these key technical problems of 3D reconstruction, in the present study, we designed a novel method based on re-imaging techniques and computer image layer processing technology. A 20-cm ulnar nerve segment from the upper arm of a fresh adult cadaver was used for acetylcholinesterase（ACh E） staining. Then, 2D panoramic images were obtained before and after ACh E staining under the stereomicroscope. Using layer processing techniques in Photoshop, a space transformation method was used to fulfill automatic registration. The contours were outlined, and the 3D rendering of functional fascicular groups in the long-segment ulnar nerve was performed with Amira 4.1 software. The re-imaging technique based on layer processing in Photoshop produced an image that was detailed and accurate. The merging of images was accurate, and the whole procedure was simple and fast. The least square support vector machine was accurate, with an error rate of only 8.25%. The 3D reconstruction directly revealed changes in the fusion of different nerve functional fascicular groups. In conclusion. The technique is fast with satisfactory visual reconstruction.展开更多
The adsorption of aqueous cadmium ions(Cd(Ⅱ)) have been investigated for modified activated carbon(AC-T)with oxygen-containing functional groups.The oxygen-containing groups of AC-T play an important role in Cd(Ⅱ) i...The adsorption of aqueous cadmium ions(Cd(Ⅱ)) have been investigated for modified activated carbon(AC-T)with oxygen-containing functional groups.The oxygen-containing groups of AC-T play an important role in Cd(Ⅱ) ion adsorption onto AC-T.The modified activated carbon is characterized by scanning electron microscopy,Fourier transform infrared spectroscopy(FT-IR) and X-ray photoelectron spectroscopy(XPS).The results of batch experiments indicate that the maximal adsorption could be achieved over the broad pH range of 4.5 to 6.5.Adsorption isotherms and kinetic study suggest that the sorption of Cd(Ⅱ) onto AC-T produces monolayer coverage and that adsorption is controlled by chemical adsorption.And the adsorbent has a good reusability.According to the FT-IR and XPS analyses,electrostatic attraction and cation exchange between Cd(Ⅱ) and oxygen-containing functional groups on AC-T are dominant mechanisms for Cd(Ⅱ) adsorption.展开更多
Rational modification by functional groups was regarded as one of efficient methods to improve the photocatalytic performance of graphitic carbon nitride(g-C3 N4).Herein,g-C3 N4 with yellow(Y-GCN)and brown(C-GCN)were ...Rational modification by functional groups was regarded as one of efficient methods to improve the photocatalytic performance of graphitic carbon nitride(g-C3 N4).Herein,g-C3 N4 with yellow(Y-GCN)and brown(C-GCN)were prepared by using the fresh urea and the urea kept for five years,respectively,for the first time.Experimental results show that the H2 production rate of the C-GCN is 39.06μmol/h,which is about 5 times of the Y-GCN.Meantime,in terms of apparent quantum efficiency(AQ.E)at 420 nm,C-GCN has a value of 6.3%and nearly 7.3 times higher than that of Y-GCN(0.86%).The results of XRD,IR,DRS,and NMR show,different from Y-GCN,a new kind of functional group of—N=CH—was firstly in-situ introduced into the C-GCN,resulting in good visible light absorption,and then markedly improving the photocatalytic performance.DFT calculation also confirms the effect of the—N=CH—group band structure of g-C3N4.Furthermore,XPS results demonstrate that the existence of—N=CH—groups in C-GCN results in tight interaction between C-GCN and Pt nanoparticles,and then improves the charge separation and photocatalytic performance.The present work demonstrates a good example of"defect engineering"to modify the intrinsic molecular structure of g-C3N4 and provides a new avenue to enhance the photocatalytic activity of g-C3N4 via facile and environmental-friendly method.展开更多
基金supported by the National Key R&D Program of China(No.2022YFC3203602)the Natural Science Foundation of China(No.52370018)+1 种基金Shaanxi Provincial Youth Innovation Team Project(No.22JP040)Shaanxi Provincial Key Scientific and Technological Innovation Team(No.2023-CX-TD-32).
文摘During the initial impoundment period of a canyon-shaped reservoir,the water body fluctuated violently regarding water level,hydrological condition,and thermal stratification.These variations may alter the structure of phytoplankton community,resulting in algal blooms and seriously threatening the ecological security of the reservoir.It is of great significance to understand the continuous changes of phytoplankton in the initial impoundment period for the protection of reservoir water quality.Therefore,a two-year in-situ monitoring study was conducted on water quality and phytoplankton in a representative canyonshaped reservoir named Sanhekou and the interannual changes of phytoplankton community and its response to environmental changes during the initial impoundment period were discussed at taxonomic versus functional classification levels.The results showed that the total nitrogen and permanganate index levels were relatively high in the first year due to rapid water storage and heavy rainfall input,and the more stable hydrological conditions in the second year promoted the increase of algae density and the transformation of community,and the proportion of cyanobacteria increased significantly.The succession order of phytoplankton in the first year of the initial impoundment periodwas Chlorophyta-Bacillariophyta-Chlorophyta,or J/F/X1-P/MP/W1-A/X1/MP,respectively.And the succession order in the second year was Cyanobacteria/Chlorophyta-Bacillariophyta-Chlorophyta,or L_(M)/G/P-P/A/X1-X1/J/G.Water temperature,relativewater column stability,mixing depth,and pHwere crucial factors affecting phytoplankton community succession.This study revealed the interannual succession law and driving factors of phytoplankton in the initial impoundment period and provided an important reference for the operation management and ecological protection of canyon-shaped reservoirs.
文摘Lithium-ion capacitors(LICs)combine the high power dens-ity of electrical double-layer capacitors with the high energy density of lithium-ion batteries.However,they face practical limitations due to the narrow operating voltage window of their activated carbon(AC)cathodes.We report a scalable thermal treatment strategy to develop high-voltage-tolerant AC cathodes.Through controlled thermal treatment of commer-cial activated carbon(Raw-AC)under a H_(2)/Ar atmosphere at 400-800℃,the targeted reduction of degradation-prone functional groups can be achieved while preserving the critical pore structure and increasing graph-itic microcrystalline ordering.The AC treated at 400℃(HAC-400)had a significant increase in specific capacity(96.0 vs.75.1 mAh/g at 0.05 A/g)and better rate capability(61.1 vs.36.1 mAh/g at 5 A/g)in half-cell LICs,along with an 83.5%capacity retention over 7400 cycles within an extended voltage range of 2.0-4.2 V in full-cell LICs.Scalability was demonstrated by a 120 g batch production,enabling fabrication of pouch-type LICs with commercial hard carbon anodes that delivered a higher energy density of 28.3 Wh/kg at 1 C,and a peak power density of 12.1 kW/kg compared to devices using raw AC.This simple,industry-compatible approach may be used for producing ad-vanced cathode materials for practical high-performance LICs.
基金supported by the National Science Foundation of China(No.21606191)the Natural Science Foundation of Shandong Province(No.ZR2020ME024).
文摘As a new electrochemical technology,capacitive deionization(CDI)has been increasingly applied in environmental water treatment and seawater desalination.In this study,functional groups modified porous hollow carbon(HC)were synthesized as CDI electrode material for removing Na^(+)and Cl^(−)in salty water.Results showed that the average diameter of HC was approximately 180 nm,and the infrared spectrum showed that its surface was successfully modified with sulfonic and amino groups,respectively.The sulfonic acid functionalized HC(HC-S)showed better electrochemical and desalting performance than the amino-functionalized HC(HC–N),with a maximum Faradic capacity of 287.4 F/g and an adsorptive capacity of 112.97 mg/g for NaCl.Additionally,92.63%capacity retention after 100 adsorption/desorption cycles demonstrates the excellent stability of HC-S.The main findings prove that HC-S is viable as an electrodematerial for desalination by high-performance CDI applications.
基金Supported by the National Natural Science Foundation of China(42172148,42172142)。
文摘Taking the Lower Silurian Longmaxi Formation shale in the Sichuan Basin as an example,this study employs atomic force microscopy-based infrared(AFM-IR)spectroscopy to analyze the submicron-scale molecular functional groups of different types and occurrences of organic matter.Combined with the quantitative evaluation of pore development via scanning electron microscopy(SEM),the response of organic pore formation and evolution mechanisms to chemical composition and structural evolution of organic matter in overmature marine shale is investigated.The results indicate that the AFM-IR spectra of graptolite periderms and pyrobitumen in shale are dominated by the stretching vibrations of conjugated C=C bonds in aromatic compounds at approximately 1600 cm-1,with weak absorption peaks near 1375,1450 and 1720 cm-1,corresponding to aliphatic chains and carbonyl/carboxyl functional groups.Overall,the AFM-IR structural indices(A and C factors)of organic matter show a strong correlation with visible porosity in shales of equivalent maturity.Lower A and C factor values correlate with enhanced development of organic pores,which is associated with the detachment of more aliphatic chains and oxygen-containing functional groups during thermal evolution.Pyrobitumen-clay mineral composites generally exhibit superior pore development,likely attributable to clay mineral dehydration participating in hydrocarbon generation reactions that promote the removal of more functional groups.Additionally,hydrocarbon generation within organic-clay composites during high-over mature stages may induce volumetric expansion,resulting in microfracturing and hydrocarbon expulsion.The associated higher hydrocarbon expulsion rates promote the formation of larger pores and fracture-shaped pores along the flake-shaped clay minerals.This study highlights that the research of submicron-scale molecular functional groups provides a deeper understanding of organic matter evolution and pores development mechanisms in overmature shales,thereby offering critical theoretical parameters for reservoir evaluation in shale oil and gas exploration.
文摘Difunctionalization of unsaturated hydrocarbons is a pivotal synthetic strategy enabling the conversion of alkenes and alkynes into high value-added compounds.It allows for the introduction of two functional groups into the unsaturated bond in a single step,facilitating the efficient construction of complex molecular architectures,which has been widely utilized in material chemistry,pharmaceutical and fine chemical synthesis.Recently,significant progress has been made via free radical-mediated difunctionalization due to the extensive application of photocatalysis.However,highly selective difunc-tionalization reactions still remain challenging.The research progress of selective difunctionalization of unsaturated hydro-carbons using a free radical addition/functional group migration strategy over the past decade is summarized,and synthetic strategies and key reaction steps are systematically elaborated.
文摘The activated carbon with high surface area was prepared by KOH activation.It was further modified by H2SO4 and HNO3 to introduce more surface functional groups.The pore structure of the activated carbons before and after modification was analyzed based on the nitrogen adsorption isotherms.The morphology of those activated carbons was characterized using scanning electronic microscopy （SEM）.The surface functional groups were determined by Fourier transform infrared spectroscopy （FTIR）.The quantity of those groups was measured by the Boehm titration method.Cr（VI） removal by the activated carbons from aqueous solution was investigated at different pH values.The results show that compared with H2SO4,HNO3 destructs the original pore of the activated carbon more seriously and induces more acidic surface functional groups on the activated carbon.The pH value of the solution plays a key role in the Cr（VI） removal.The ability of reducing Cr（VI） to Cr（III） by the activated carbons is relative to the acidic surface functional groups.At higher pH values,the Cr（VI） removal ratio is improved by increasing the acidic surface functional groups of the activated carbons.At lower pH values,however,the acidic surface functional groups almost have no effect on the Cr（VI） removal by the activated carbon from aqueous solution.
基金supported by the National Natural Science Foundation of China(Nos.21477146,21577163)the National Key Research and Development Program of China(No.2017YFF0211203-3)+1 种基金the Key Research Program of Frontier Sciences,CAS(No.QYZDJ-SSW-DQC020-02)the Chinese Academy of Sciences(No.XDB14040101)
文摘Graphene quantum dots(GQDs) possess great potential in various applications due to their superior physicochemical properties and wide array of available surface modifications.However, the toxicity of GQDs has not been systematically assessed, thus hindered their further development; especially, the risk of surface modifications of GQDs is largely unknown. In this study, we employed a lung carcinoma A549 cells as the model to investigate the cytotoxicity and autophagy induction of three types GQDs, including cGQDs(COOH-GQDs), hGQDs(OH-GQDs), and aGQDs(NH_2-GQDs). The results showed hGQDs was the most toxic, as significant cell death was induced at the concentration of 100 μg/mL,determining by WST-1 assay as well as Annexin-V-FITC/PI apoptosis analysis, whereas cGQDs and aGQDs were non-cytotoxic within the measured concentration. Autophagy detection was performed by TEM examination, LC3 fluorescence tracking, and Westernblot. Both aGQDs and hGQDs induced cellular autophagy to various degrees except for cGQDs. Further analysis on autophagy pathways indicated all GQDs significantly activated p-p38 MAPK; p-ERK1/2 was inhibited by aGQDs and hGQDs but activated by c GQDs. p-JNK was inhibited by aGQDs and c GQDs, while activated by hGQDs. Simultaneously, Akt was activated by hGQDs but inhibited by aGQDs. Inhibition of autophagy by 3-MA significantly increased the cytotoxicity of GQDs, suggesting that autophagy played a protective role against the toxicity of GQDs. In conclusion, c GQDs showed excellent biocompatibility and may be considered for biological applications. Autophagy induction may be included in the health risk assessment of GQDs as it reflects the stress status which may eventually lead to diseases.
基金support from the National Natural Science Foundation of China(No.21901206)Postdoctoral Science Foundation of China(No.2022M712589)+2 种基金General Key R&D Projects in Shaanxi Province(No.2023-YBGY-321)Natural Science Foundation of Chongqing(No.CSTB2022NSCQ-MSX0826)National&Local Joint Engineering Research Center for mineral Salt Deep Utilization,Huaiyin Institute of Technology(No.SF202407)for financial support。
文摘The transition metal-catalyzed C–H activation have been considered as increasingly useful approach for installing new functional groups onto organic small molecules due to their high step-and atom-economy,the abundance of hydrocarbon compounds,and the potential for late-stage functionalization of complex organic molecules.The ortho-and meta-C-H activation and functionalization of aromatic compounds have been widely explored in recent years,however the distal para-C-H activation and functionalization has remained a significant challenge because of the difficulty in forming energetically favorable metallacyclic transition states.The utilization of appropriate directing groups or templates as well as the meticulous design of catalysts and ligands has proven to be effective in transition-metal-catalyzed remote para-C-H bonds activation and functionalization of aromatic compounds.This review aims to summarize the strategies for controlling para-selective C–H functionalization using the directing group,template engineering,and catalyst/ligand design under transition metals catalysis in recent years.
基金supported by the National Natural Science Foundation of China(Nos.22375122 and 22105065)the National Science Fund for Distinguished Young Scholars(No.52225301)+3 种基金the National Key R&D Program of China(Nos.2020YFA0710400 and 2020YFA0710402)the 111 Project(No.B14041)Fundamental Research Funds for Central Universities(No.GK202304040)Open Project of the State Key Laboratory of Supramolecular Structure and Materials(No.sklssm2024023)。
文摘Amyloid-like proteins are critical for interfacial adhesion across various marine organisms and bacteria.However,the specific contributions of different functional residues remain unclear.Herein,we introduce an approach to deconstruct and mimic these residues using synthetic homopolymers and random copolymers with phenyl,amino,carboxyl,and hydroxyl functional groups using reversible addition-fragmentation chain transfer(RAFT)polymerization.The resulting polymers,designed with comparable molecular weights(M_(n):10–20 kDa)and narrow dispersities(PDI<1.3),mimic the diverse surface chemistry of amyloid-like proteins,enabling systematic investigation of their adhesive properties.The interfacial adhesion forces of different polymer films were quantified using atomic force microscopy(AFM)with a colloidal probe.Remarkably copolymers with multiple functional groups demonstrated significantly enhanced adhesion compared to homopolymers,a trend corroborated by macroscopic shear strength and stability tests.These results highlight that the synergistic effects of multiple functional groups are crucial for achieving universal interfacial adhesion of macromolecules,offering insights into protein adhesion mechanisms,and guiding polymer-based interfacial modifications.
基金Funded by the National Nature Science Foundation of China(No.51521001)
文摘The functional groups on graphene sheets surface affect their dispersion and interfacial adhesion in polymer matrix. We compared the mechanical property of polymethymethacrylate（PMMA） microcellular foams reinforced with graphene oxide（GO） and reduced graphene oxide（RGO） to investigate this influence of functional groups. RGO sheets were fabricated by solvent thermal reduction in DMF medium. UV-Vis, FT-IR and XPS analyses indicate the difference of oxygen-containing groups on GO and RGO sheets surface. The observation of SEM illustrates that the addition of a smaller number of GO or RGO sheets causes a fine cellular structure of PMMA foams with a higher cell density(about 1011 cells/cm3) and smaller cell sizes（about 1-2 μm） owing to their remarkable heterogeneous nucleation effect. Compared to GO reinforced foams, the RGO/PMMA foams own lower cell density and bigger cell size in their microstructure, and their compressive strength is lower even when the reinforcement contents are the same and the foam bulk density is higher. These results indicate that the oxygen-containing groups on GO sheets’ surface are beneficial to adhere CO2 to realize a larger nucleation rate, and their strong interaction with PMMA matrix improves the mechanical property of PMMA foams.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB03030401 & XDA05060700)the National Natural Science Foundation of China (Grant Nos. 41171044, 31070391, 41271067)the General Financial Grant from the China Postdoctoral Science Foundation (Grant No. 2013M530716)
文摘Variations in the fractions of biomass allocated to functional components are widely considered as plant responses to resource availability for grassland plants. Observations indicated shoots isometrically relates to roots at the community level but allometrically at the species level in Tibetan alpine grasslands. These differences may result from the specific complementarity of functional groups between functional components, such as leaf, root, stem and reproductive organ. To test the component complementary responses to regional moisture variation, we conducted a multi-site transect survey to measure plant individual size and component biomass fractions of common species belonging to the functional groups： forbs, grasses, legumes and sedges on the Northern Tibetan Plateau in peak growing season in 2010. Along the mean annual precipitation （MAP） gradient, we sampled 7o species, in which 2o are in alpine meadows, 20 in alpine steppes, 15 in alpine desert-steppes and 15 in alpine deserts, respectively. Our results showed that the size of alpine plants is small with individual biomass mostly lower than 1.0 g. Plants keep relative conservative component individual responses moisture functional fractions across alpine grasslands at the level. However, the complementary between functional components to variations specifically differ among groups. These results indicate that functional group diversity may be an effective tool for scaling biomass allocation patterns from individual up to community level. Therefore, it is necessary andvaluable to perform intensive and systematic studies on identification and differentiation the influences of compositional changes in functional groups on ecosystem primary services and processes.
基金Funded by the National Natural Science Foundation of China(No.51808369)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.18KJB560016)+3 种基金the Opening Project of State Key Laboratory of Green Building Materials(No.YA-615)the State Key Laboratory of Silicate Materials for Architectures(No.SYSJJ2018-09)Science and Technology Project of Jiangsu Provincal Department of Housing and Urban-Rural Construction(No.2018ZD049)the Natural Science Foundation of Suzhou University of Science and Technology(No.XKQ2018009)
文摘The adsorption behaviors and dispersing properties of polycarboxylate superplasticizer(PCE) with different functional groups were systematically analyzed to reveal the theory and methods of modifying PCE molecular structures and regulating PCE performances. By substituting carboxylic groups with sulfonic groups, ester groups or acylamino groups, respectively, modified PCEs with different functional groups were synthesized. Results show that introducing low amount of ester groups or sulfonic groups into the PCE molecules has no negative effects on the fluidity of cement paste, while introducing acylamino groups into PCE molecules significantly weakens the fluidity of cement paste. At low amount(when the molar ratio of sodium methallyl sulfonate to TPEG is lower than 0.4), the rapid adsorption of sulfonic groups onto the cement particles contributes to the high dispersing performance of the sulfonic group modified PCEs. When the substitution ratio of acrylic acid by sulfonic acid is higher than 0.4, the viscosity and the yield stress of cement paste increases sharply. Redundant sulfonic groups lead to the excessive charge density of the PCE, which contributes to the inhomogeneous adsorption on the cement grains and hence results in the decline of the dispersing performance. Substitution of carboxylic group by acylamino group or ester group slightly changes the viscosity as well as the yield stress of cement paste. Introducing sulfonic group into PCE molecule improves the adsorption behavior of PCEs, while introducing ester group or acylamino group into PCE depresses the adsorption properties.
基金supported by the National Science Foundation of China(Nos.41172143 and 40872101)Developmental Plan of Basic Research on Natural Science of Shanxi Province(20012JM5005)Science Research Plan of Shanxi education department(12JK0483)
文摘The relationship between trace elements in coal and organic functional groups of coal, also some of aromatic structure, was investigated by using curve fitting of infrared spectra. Cluster analysis was also performed according to the degree of affinity of organic groups to the trace elements. The results show that there is a possibility that trace elements, especially LREE, were bound to peripheral organic functional groups of middle rank coal macromolecule. The most possible functional group that binds trace element is the hydroxyl, and to the less degree, the asymmetric -CH3 and 〉CH2 stretching, -CH3 stretching, etc. The degree of affinity of trace elements to different functional groups varies. The tendency obeys the natural structural changing law of trace elements-- the periodic law. The deviation of some trace elements from this regular trend is attributed to the deviation of intrinsic ＂confusion degree＂ （conventional molar entropy） of the matter system of coal basin, which is affected by the inner and outer factors during the evolution.
基金The National Natural Science Foundation of China under contract Nos 40676076 and 30700069the Darwin Initiative Programme under contract No.14-015a grant from the Center of Excellence in Biodiversity Research,King Saud University
文摘The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao,Shandong Province,China,during a six-month study period （a complete shrimp-culture cycle） from May to October 2002.The results reveal that： （1） the protist communities represented five trophic and functional groups of the species identified,about 60% were photoautotrophs,20% algivores,12% bacterivores,5% raptors and about 3% non-selectives;（2） the photoautotrophs,algivores and bacterivores were the primary contributors to the changes in the protist communities in short temporal scales,the succession of dominance typically being bacterivores→photoautotrophs→algivores,with the raptors dominating the protist communities in a single sample （early June）;（3） the photoautotrophs and non-selectives were the primary contributors to the peak of protist abundance in early October whereas the photoautotrophs,bacterivores,raptors and non-selectives mainly gave rise to two bimodal peaks of biomass in July and October respectively;（4） five functional groups of protist communities represented significant correlations with water nutrients （i.e.,NH 3-N,NO 3-N,and PO 4 ）,either alone or in combination with temperature,of which algivores and raptors were strongly correlated with phosphate and the concentration of Chl a,while bacterivores were strongly related to nitrogen and the concentration of bacteria.These findings confirm that planktonic protists are potentially useful bioindicators of water quality in the semi-enclosed mariculture system.
基金supported by the National Natural Science Foundation of China (No.31370472)the State Key Laboratory of Freshwater Ecology and Biotechnology (No.2014FBZ01)the Major Science and Technology Program for Water Pollution Control and Treatment (No.2013ZX07102-005)
文摘Historical data indicate that the dominance of submerged plants in Dianchi Lake in the 1960 s was characterized by low algal density with dominance of non-toxic group J（Scenedesmus,Pediastrum,etc.）. The removal of submerged plants,which began in the 1970 s,resulted in the expansion of bloom-forming Microcystis（group M）. Laboratory experiments suggested that Microcystis aeruginosa was inclined to grow and develop at elevated temperatures. The growth of Scenedesmus obliquus was slower than that of co-cultivated M. aeruginosa in the absence of Ceratophyllum demersum,especially at higher temperatures. The existence of submerged plant C. demersum could inhibit the growth of the harmful algae M. aeruginosa and this inhibitory effect by C. demersum was enhanced with an increase in temperature. Instead,with C. demersum,the growth of S. obliquus was not inhibited,but the co-cultivated M. aeruginosa was eliminated in a short time. Combined with the historical data and laboratory experiments,it was indicated that the submerged plants might play important roles in the dominance of the non-toxic group J in the historical succession. Consequently,the introduction of the submerged plant such as C. demersum might alter the dominant phytoplankton functional groups from M to J and benefit the restoration of the eutrophic lake.
基金The authors are grateful to the financial support by the Postdoctoral Science Foundation of China(No.2003034330)the Science Foundation for mid-youth elite of Shangdong Province+1 种基金the Natural Science Foundation of Shangdong Province(No.Q99B15)the National Natural Science Foundation of China(No.2906008)
文摘A series of new chelating resins with incorporating heterocyclic functional groups： pyridine, thiadizole, benzothizole into macroporous chloromethylated polystyrene were synthesized via hydrophilic spacer arm of polyethylene glycol containing sulfur. These chelating resins were found to show high adsorption capacities for Ag^＋, Hg^2＋, Au^3＋ and Pd^2＋, and the presence of spacer arm can enhance adsorption ability due to increase the hydrophilicity of the chelating resins.
基金Supported by the National Natural Science Foundation of China(No.U1612442)the Science and Technology Foundation of Guizhou Province(Nos.[2020]6009,[2020]4Y009)Anton Brancelj was supported by Slovenian Research Agency(ARRS)(No.P1-0255)。
文摘Reservoirs are an important water source in many densely populated areas in southwest China.Phytoplankton play an essential role in maintaining the structure and function of reservoir ecosystems.Understanding the succession in phytoplankton communities and the factors driving it are essential for eff ective water quality management in drinking water reservoirs.In this study,water samples were collected monthly at the surface layers from March 2016 to December 2019 in Hongfeng Reservoir,southwest China.The relationship between functional group succession was analyzed based on nonmetric multidimensional scaling analysis(NMDS),redundancy analysis(RDA),succession rate,and other analysis methods.The results showed distinct shifts in the community structure of phytoplankton functional groups within study period.The Cyclotella sp.was dominant in 2016 and 2017,and Pseudanabaena limnetica was the dominant group in 2018 and 2019.It appears that the phytoplankton composition and biomass are closely related to the water temperature and nutrient status in this reservoir.The results clearly showed that the permanganate index(COD_(Mn))was the key factor of dramatic phytoplankton functional group succession,and the change in succession rates was closely caused by total nitrogen concentration(TN).Therefore,the succession pattern and key factors of Hongfeng Reservoir revealed in this study were important guidance for the management of drinking water reservoirs in southwest China.A reasonable limit on exogenous nutrient input should be a priority,especially in high water temperature period.
基金supported by the National Natural Science Foundation of China,No.30571913a grant from the Science and Technology Project of Guangdong Province of China,No.2013B010404019+1 种基金the Natural Science Foundation of Guangdong Province of China,No.9151008901000006the Medical Scientific Research Foundation of Guangdong Province of China,No.A2009173
文摘The three-dimensional（3D） visualization of the functional bundles in the peripheral nerve provides direct and detailed intraneural spatial information. It is useful for selecting suitable surgical methods to repair nerve defects and in optimizing the construction of tissue-engineered nerve grafts. However, there remain major technical hurdles in obtaining, registering and interpreting 2D images, as well as in establishing 3D models. Moreover, the 3D models are plagued by poor accuracy and lack of detail and cannot completely reflect the stereoscopic microstructure inside the nerve. To explore and help resolve these key technical problems of 3D reconstruction, in the present study, we designed a novel method based on re-imaging techniques and computer image layer processing technology. A 20-cm ulnar nerve segment from the upper arm of a fresh adult cadaver was used for acetylcholinesterase（ACh E） staining. Then, 2D panoramic images were obtained before and after ACh E staining under the stereomicroscope. Using layer processing techniques in Photoshop, a space transformation method was used to fulfill automatic registration. The contours were outlined, and the 3D rendering of functional fascicular groups in the long-segment ulnar nerve was performed with Amira 4.1 software. The re-imaging technique based on layer processing in Photoshop produced an image that was detailed and accurate. The merging of images was accurate, and the whole procedure was simple and fast. The least square support vector machine was accurate, with an error rate of only 8.25%. The 3D reconstruction directly revealed changes in the fusion of different nerve functional fascicular groups. In conclusion. The technique is fast with satisfactory visual reconstruction.
基金Supported by the Fundamental Research Funds for the Central Universities(TD2013-2,2012LYB33)the National Natural Science Foundation of China(51278053,21373032)grant-in-aid from Kochi University of Technology and China Scholarship Council
文摘The adsorption of aqueous cadmium ions(Cd(Ⅱ)) have been investigated for modified activated carbon(AC-T)with oxygen-containing functional groups.The oxygen-containing groups of AC-T play an important role in Cd(Ⅱ) ion adsorption onto AC-T.The modified activated carbon is characterized by scanning electron microscopy,Fourier transform infrared spectroscopy(FT-IR) and X-ray photoelectron spectroscopy(XPS).The results of batch experiments indicate that the maximal adsorption could be achieved over the broad pH range of 4.5 to 6.5.Adsorption isotherms and kinetic study suggest that the sorption of Cd(Ⅱ) onto AC-T produces monolayer coverage and that adsorption is controlled by chemical adsorption.And the adsorbent has a good reusability.According to the FT-IR and XPS analyses,electrostatic attraction and cation exchange between Cd(Ⅱ) and oxygen-containing functional groups on AC-T are dominant mechanisms for Cd(Ⅱ) adsorption.
基金financial support of the National Natural Science Foundation of China(NSFC,Nos.51622806,51878325,51868050,51378246 and 51720105001)the Natural Science Foundation of Jiangxi Province(Nos.20162BCB22017,20165BCB18008,20171ACB20017,20133ACB21001 and 20171BAB206049)。
文摘Rational modification by functional groups was regarded as one of efficient methods to improve the photocatalytic performance of graphitic carbon nitride(g-C3 N4).Herein,g-C3 N4 with yellow(Y-GCN)and brown(C-GCN)were prepared by using the fresh urea and the urea kept for five years,respectively,for the first time.Experimental results show that the H2 production rate of the C-GCN is 39.06μmol/h,which is about 5 times of the Y-GCN.Meantime,in terms of apparent quantum efficiency(AQ.E)at 420 nm,C-GCN has a value of 6.3%and nearly 7.3 times higher than that of Y-GCN(0.86%).The results of XRD,IR,DRS,and NMR show,different from Y-GCN,a new kind of functional group of—N=CH—was firstly in-situ introduced into the C-GCN,resulting in good visible light absorption,and then markedly improving the photocatalytic performance.DFT calculation also confirms the effect of the—N=CH—group band structure of g-C3N4.Furthermore,XPS results demonstrate that the existence of—N=CH—groups in C-GCN results in tight interaction between C-GCN and Pt nanoparticles,and then improves the charge separation and photocatalytic performance.The present work demonstrates a good example of"defect engineering"to modify the intrinsic molecular structure of g-C3N4 and provides a new avenue to enhance the photocatalytic activity of g-C3N4 via facile and environmental-friendly method.
