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
Based on the parent tetrazole 2N-oxide, six series of novel carbon-linked ditetrazole 2N- oxides with different energetic substituent groups （-NH2, -Na, -NO2, NF2, -NHNO2） and energetic bridge groups （-CH2-, -CH2-C...Based on the parent tetrazole 2N-oxide, six series of novel carbon-linked ditetrazole 2N- oxides with different energetic substituent groups （-NH2, -Na, -NO2, NF2, -NHNO2） and energetic bridge groups （-CH2-, -CH2-CH2-, -NH-, -N=N-, -NH-NH-） were designed. The overall performance and the effects of different energetic substituent groups and energetic bridge groups on the performance were investigated by density functional theory and electrostatic potential methods. The results showed that most of designed compounds have oxygen balance around zero, high heats of formation, high density, high energy, and acceptable sensitivity, indicating that tetrazole N-oxide is a useful parent energetic compound employed for obtaining high energy compounds, even only combined with some very common energetic substituent groups and bridge groups. Comprehensively considering the effects on energy and sensitivity, the -NO2, -NF2, -NH- and-NH-NH- are appropriate substituent groups for combining tetrozale N-oxide to design new energetic compounds, while -NH2, -Na, -CH2-CH2-, and -N=N- are inappropriate.展开更多
[Objective]The aim was to carry out stoichiometry on the early-spring herbs functional group in subtropical artificial wetland.[Method]UV-Vis spectrophotometer was used for the determination of nitrate-nitrogen,ammoni...[Objective]The aim was to carry out stoichiometry on the early-spring herbs functional group in subtropical artificial wetland.[Method]UV-Vis spectrophotometer was used for the determination of nitrate-nitrogen,ammonium nitrogen and phosphorus concentrations.Potassium persulfate absorptiometry was used for the measurement of total N content,while the flame photometer was used to detect the potassium and sodium concentration in plants.All the nutrient determination of plant samples were repeated for four times.[Result]The four nutrient concentrations in almost all samples were in the normal range of natural plant nutrition concentrations;in early-spring herbs functional groups,different species showed diversity on the nutrient concentrations;plant height had no significant effect on the nutrient concentrations in plants;the nutrient concentrations of non-grass group plants were higher than that of grass group plants;the nutrient concentrations of the annual herb were higher than that of perennial herbs.[Conclusion]The study had provided basis for the understanding of the effects of changes in nutritional conditions on species diversity,community structure and succession of the system.展开更多
The incorporation of small fluorinated functional groups,including CF_(3),CF_(2)H,and CFH_(2),into small molecules represents a crucial strategy for modulating their physical,chemical,and biological characteristics[1,...The incorporation of small fluorinated functional groups,including CF_(3),CF_(2)H,and CFH_(2),into small molecules represents a crucial strategy for modulating their physical,chemical,and biological characteristics[1,2].Consequently,organofluorine compounds are frequently encountered in pharmaceuticals and agrochemicals.Significant advances have been made in the introduction of fluoroalkyl groups into small molecules since the beginning of the 21st century.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
Biochar(BC)are widely used as highly efficient adsorbents to alleviate aromatics-based contaminants due to their ease of preparation,wide availability,and high sustainability.The surface properties of BCs usually vary...Biochar(BC)are widely used as highly efficient adsorbents to alleviate aromatics-based contaminants due to their ease of preparation,wide availability,and high sustainability.The surface properties of BCs usually vary greatly due to their complex chemical constituents and different preparation processes and are reflected in the values of parameters such as the specific surface area(SSA),pore volume/size,and surface functional groups(SFGs).The effects of SSA and pore volume/size on the adsorption of aromatics have been widely reported.However,the corresponding mechanisms of BC SFGs towards aromatics adsorption remains unclear as the compositions of the SFGs are usually complex and hard to determine.To address in this gap in the literature,this review introduces a new perspective on the adsorption mechanisms of aromatics.Through collecting previously-reported results,the parameters log P(logarithm of the Kow),polar surface area,and the positive/negative charges were carefully calculated using Chem Draw3D,which allowed the hydrophobicity/hydrophilicity properties,electron donor-acceptor interactions,Hbonding,and electrostatic interactions between SFGs and aromatics-based contaminates to be inferred intuitively.These predictions were consistent with the reported results and showed that tailor-made BCs can be designed according to the molecular weights,chemical structures,and polarities of the target aromatics.Overall,this review provides new insight into predicting the physicochemical properties of BCs through revealing the relationship between SFGs and adsorbates,which may provide useful guidance for the preparing of highly-efficient,functional BCs for the adsorption of aromatics.展开更多
Stable carbon isotopes(δ^(13)C)are extensively utilized to study intrinsic water use efficiency(iWUE)at the leaf-scale in terrestrial ecosystems,serving as a crucial metric for assessing plant adaptation to climate c...Stable carbon isotopes(δ^(13)C)are extensively utilized to study intrinsic water use efficiency(iWUE)at the leaf-scale in terrestrial ecosystems,serving as a crucial metric for assessing plant adaptation to climate change.However,there is currently a lack of consensus regarding the leaf-scale iWUE variation characteristics among different functional types.In this study,we measured theδ^(13)Cleaf and iWUE values of different functional plants(i.e.,life forms,leaf types,and mycorrhizal types)from 120 species across distinct habitat types(i.e.,hillside,nearpeak,and peak)in a subtropical forest on the western slope of Wuyi Mountains,southern China.The results showed that theδ^(13)Cleaf values of plants on the western slope of Wuyi Mountains ranged from-34.63‰to-30.04‰,and iWUE ranged from 5.93μmol mol^(-1)to 57.34μmol mol^(-1).Theδ^(13)Cleaf and iWUE values differed significantly among plant life forms,following the order of herbs>vine plants>shrubs>trees.Theδ^(13)Cleaf and iWUE values of ectomycorrhizal(ECM)species were greater than those of arbuscular mycorrhizal(AM)species despite there being no significant difference between plants with different leaf types(Simple leaves(SL)vs.Compound leaves(CL)).From the hillside to the peak,both at the community level and at the species level,theδ^(13)C values of leaves and iWUE values of plants exhibited an upward trend.The regression analysis revealed that leaf-scale iWUE was significantly negatively correlated with soil water content and significantly positively correlated with leaf phosphorus content.The findings indicated that leaf carbon isotope fractionation and corresponding iWUE can be influenced by life form,mycorrhizal type,and soil water availability.These insights provide a deeper understanding of the coupling mechanisms of carbon,water,and nutrients among different functional plant types in subtropical forests,and offer insights into predicting plant adaptability under climate change.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
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
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
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
In this work,a modification method of H_(3)PO_(4)plus H_(2)O_(2)(PHP)was introduced to targetedly form abundant oxygenated functional groups(OFGs)on biochar,and methylene blue(MB)was employed as a model pollutant for ...In this work,a modification method of H_(3)PO_(4)plus H_(2)O_(2)(PHP)was introduced to targetedly form abundant oxygenated functional groups(OFGs)on biochar,and methylene blue(MB)was employed as a model pollutant for adsorption to reflect the modification performance.Results indicated that parent biochars,especially derived from lower temperatures,substantially underwent oxidative modification by PHP,and OFGs were targetedly produced.Correspondingly,approximately 21.5-fold MB adsorption capacity was achieved by PHP-modified biochar comparing with its parent biochar.To evaluate the compatibility of PHP-modification,coefficient of variation(CV)based on MB adsorption capacity by the biochar from various precursors was calculated,in which the CV of PHP-modified biochars was 0.0038 comparing to0.64 of the corresponding parent biochars.These results suggested that the PHP method displayed the excellent feedstock compatibility on biochar modification.The maximum MB adsorption capacity was454.1 mg/g when the H_(3)PO_(4)and H_(2)O_(2)fraction in PHP were 65.2%and 7.0%;the modification was further intensified by promoting temperature and duration.Besides,average 94.5%H_(3)PO_(4)was recovered after 10-batch modification,implying 1.0 kg H_(3)PO_(4)(85%)in PHP can maximally modify 2.37 kg biochar.Overall,this work offered a novel method to tailor biochar towards OFGs-rich surface for efficient adsorption.展开更多
Livestock ranching is one of the main productive activities in arid regions of the world.Grazing produces changes in animal as well as plant communities(e.g.richness,abundance and species dominance relationships).Ants...Livestock ranching is one of the main productive activities in arid regions of the world.Grazing produces changes in animal as well as plant communities(e.g.richness,abundance and species dominance relationships).Ants are good biological indicators due to the environmental fidelity of some of their community parameters.We described the functional structure of the ant community in the central Monte of Mendoza,Argentina,and examined the effect of grazing using richness,diversity and the functional group scheme.We used pitfall traps to sample ants at a reserve with 30-year cattle exclusion and at an adjacent ranch.Eleven of the 27 recorded species showed significant differences in their abundance and two species were absent at the ranch.While richness and diversity did not reflect these differences,functional groups did.Hot Climate Specialists were more abundant at the ranch while Cryptic Species and Generalized Myrmicinae increased at the reserve.This study supports the utility of the functional group scheme to study the effects of grazing disturbance in ant communities of arid regions.展开更多
Several of new chelating resins containing sulfoxide and heterocyclic functional groups （3-aminopyridine and 2-mercaptobenzothiazole） based on macroporous chloromethylated polystyrene were synthesized and characteri...Several of new chelating resins containing sulfoxide and heterocyclic functional groups （3-aminopyridine and 2-mercaptobenzothiazole） based on macroporous chloromethylated polystyrene were synthesized and characterized by elemental analysis and infrared spectra. Their adsorption capacities towards Zn^2＋, Cu^2＋, Pb^2＋, Hg^2＋ and Ag^＋ at pH 3.0 and 6.0 were investigated in detail. It was found that the adsorption capacities of the resins containing bis[（3-pyridylaminoethyl）sulfoxide or （2-benzothiazolylthioethyl）sulfoxide for the above ions were higher than that on ones containing single above-mentioned groups.展开更多
Correlations among free radicals, apparent activation energy, and functional groups during lowtemperature oxidation of Jurassic coal in Northern Shaanxi were investigated by examining three coal samples collected from...Correlations among free radicals, apparent activation energy, and functional groups during lowtemperature oxidation of Jurassic coal in Northern Shaanxi were investigated by examining three coal samples collected from the Ningtiaota, Jianxin, and Shigetai coal mines. Free radical concentrations at less than 120 ℃ were investigated by electron spin resonance experiments while the thermogravimetric experiments were conducted to analyze apparent activation energies. In addition, Fourier transform infrared spectroscopy was employed to study the spectrum of functional groups generated in coal. The results indicated that, in decreasing order, the apparent activation energies were Shigetai 〉Jianxin 〉 Ningtiaota, indicating that, from 50 to 120 ℃, the Ningtiaota coal sample most easily absorbed and reacted with oxygen while the most resistant was the Shigetai coal sample. Free radical concentrations and line heights increased with increased temperature, and the line width and Lande factor showed irregular fluctuations. Functional group variations were different among these coals, and the phenol and alcohol-associated OHs, carboxyls, and aromatic ring double bonds might have had a major impact on free radical concentrations. These results were meaningful for better consideration and management of coal oxidation at low temperatures.展开更多
The thermal deactivation of diesel soot particles exerts a significant influence on the control strategy for the regeneration of diesel particulate filters(DPFs).This work focused on the changes in the surface functio...The thermal deactivation of diesel soot particles exerts a significant influence on the control strategy for the regeneration of diesel particulate filters(DPFs).This work focused on the changes in the surface functional groups,carbon chemical state,and graphitization degree during thermal treatment in an inert gas environment at intermediate temperatures of 600℃,800℃,and 1000℃ and explore the chemical species that were desorbed from the diesel soot surface during thermal treatment using a thermogravimetric analyser coupled with a gas-chromatograph mass spectrometer(TGA-GC/MS).The surface functional groups and carbon chemical statewere characterized using Fourier transform infrared spectroscopy(FT-IR)and X-ray photoelectron spectroscopy(XPS).The graphitization degree was evaluated by means of Raman spectroscopy(RS).The concentrations of aliphatic C–H,C–OH,C=O,and O–C=O groups are reduced for diesel soot and carbon black when increasing the thermal treatment temperature,while the sp^(2)/sp^(3) hybridized ratio and graphitization degree enhance.These results provide comprehensive evidence of the decreased reactivity of soot samples.Among oxygenated functional groups,the percentage reduction during thermal treatment is the largest for the O–C=O groups owing to its worst thermodynamic stability.TGA-GC/MS results show that the aliphatic and aromatic chains and oxygenated species would be desorbed from the soot surface during 1000℃ thermal treatment of diesel soot.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.
基金This work was supported by the Natural Science Foundation of Nanjing Institute of Technology （YKJ201507, CKJA201603） and the Youth Natural Sci- ence Foundation of Jiangsu Province （BK20160774）, and Outstanding Scientific and Technological Innovation Team in Colleges and Universities of Jiangsu Province.
文摘Based on the parent tetrazole 2N-oxide, six series of novel carbon-linked ditetrazole 2N- oxides with different energetic substituent groups （-NH2, -Na, -NO2, NF2, -NHNO2） and energetic bridge groups （-CH2-, -CH2-CH2-, -NH-, -N=N-, -NH-NH-） were designed. The overall performance and the effects of different energetic substituent groups and energetic bridge groups on the performance were investigated by density functional theory and electrostatic potential methods. The results showed that most of designed compounds have oxygen balance around zero, high heats of formation, high density, high energy, and acceptable sensitivity, indicating that tetrazole N-oxide is a useful parent energetic compound employed for obtaining high energy compounds, even only combined with some very common energetic substituent groups and bridge groups. Comprehensively considering the effects on energy and sensitivity, the -NO2, -NF2, -NH- and-NH-NH- are appropriate substituent groups for combining tetrozale N-oxide to design new energetic compounds, while -NH2, -Na, -CH2-CH2-, and -N=N- are inappropriate.
基金Supported by National Natural Science Foundation of China(30370146)~~
文摘[Objective]The aim was to carry out stoichiometry on the early-spring herbs functional group in subtropical artificial wetland.[Method]UV-Vis spectrophotometer was used for the determination of nitrate-nitrogen,ammonium nitrogen and phosphorus concentrations.Potassium persulfate absorptiometry was used for the measurement of total N content,while the flame photometer was used to detect the potassium and sodium concentration in plants.All the nutrient determination of plant samples were repeated for four times.[Result]The four nutrient concentrations in almost all samples were in the normal range of natural plant nutrition concentrations;in early-spring herbs functional groups,different species showed diversity on the nutrient concentrations;plant height had no significant effect on the nutrient concentrations in plants;the nutrient concentrations of non-grass group plants were higher than that of grass group plants;the nutrient concentrations of the annual herb were higher than that of perennial herbs.[Conclusion]The study had provided basis for the understanding of the effects of changes in nutritional conditions on species diversity,community structure and succession of the system.
基金supported by the National Natural Science Foundation of China(22378205)the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Center for Advanced Materials and Technology in Nanjing University of Science and Technology。
文摘The incorporation of small fluorinated functional groups,including CF_(3),CF_(2)H,and CFH_(2),into small molecules represents a crucial strategy for modulating their physical,chemical,and biological characteristics[1,2].Consequently,organofluorine compounds are frequently encountered in pharmaceuticals and agrochemicals.Significant advances have been made in the introduction of fluoroalkyl groups into small molecules since the beginning of the 21st century.
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.
基金funded by the National Natural Science Foundation of China(No.51961165104)Project of Thousand Youth Talents(No.AUGA2160100917)+1 种基金University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(No.UNPYSCT-2020050)Provincial Leading Talent Echelon Cultivation Project of Heilongjiang Institute of Technology(No.2020LJ04)。
文摘Biochar(BC)are widely used as highly efficient adsorbents to alleviate aromatics-based contaminants due to their ease of preparation,wide availability,and high sustainability.The surface properties of BCs usually vary greatly due to their complex chemical constituents and different preparation processes and are reflected in the values of parameters such as the specific surface area(SSA),pore volume/size,and surface functional groups(SFGs).The effects of SSA and pore volume/size on the adsorption of aromatics have been widely reported.However,the corresponding mechanisms of BC SFGs towards aromatics adsorption remains unclear as the compositions of the SFGs are usually complex and hard to determine.To address in this gap in the literature,this review introduces a new perspective on the adsorption mechanisms of aromatics.Through collecting previously-reported results,the parameters log P(logarithm of the Kow),polar surface area,and the positive/negative charges were carefully calculated using Chem Draw3D,which allowed the hydrophobicity/hydrophilicity properties,electron donor-acceptor interactions,Hbonding,and electrostatic interactions between SFGs and aromatics-based contaminates to be inferred intuitively.These predictions were consistent with the reported results and showed that tailor-made BCs can be designed according to the molecular weights,chemical structures,and polarities of the target aromatics.Overall,this review provides new insight into predicting the physicochemical properties of BCs through revealing the relationship between SFGs and adsorbates,which may provide useful guidance for the preparing of highly-efficient,functional BCs for the adsorption of aromatics.
基金supported by the Open Research Fund of Jiangxi Provincial Academy of Water Resources Sciences(2022SKTR05&2022SKTR03)the National Natural Science Foundation of China(42067049&42367049),the Jiangxi Provincial Natural Science Foundation(20242BAB25350)+5 种基金the Research Project of the Jiangxi Provincial Department of Forestry(CXZX(2025)14 and JXTG(2023)15)the Ganpo Juncai Plan(QN2023018)the Ganpo Yingcai Plan(gpyc20240038)the Double Thousand Plan of Jiangxi Province(jxsq2023102213 and jxsq2023102214)the Jiangxi Province“Science and Technology+Water Resources”Joint Plan Project(2023KSG01001)the Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province(20243BCE51025).
文摘Stable carbon isotopes(δ^(13)C)are extensively utilized to study intrinsic water use efficiency(iWUE)at the leaf-scale in terrestrial ecosystems,serving as a crucial metric for assessing plant adaptation to climate change.However,there is currently a lack of consensus regarding the leaf-scale iWUE variation characteristics among different functional types.In this study,we measured theδ^(13)Cleaf and iWUE values of different functional plants(i.e.,life forms,leaf types,and mycorrhizal types)from 120 species across distinct habitat types(i.e.,hillside,nearpeak,and peak)in a subtropical forest on the western slope of Wuyi Mountains,southern China.The results showed that theδ^(13)Cleaf values of plants on the western slope of Wuyi Mountains ranged from-34.63‰to-30.04‰,and iWUE ranged from 5.93μmol mol^(-1)to 57.34μmol mol^(-1).Theδ^(13)Cleaf and iWUE values differed significantly among plant life forms,following the order of herbs>vine plants>shrubs>trees.Theδ^(13)Cleaf and iWUE values of ectomycorrhizal(ECM)species were greater than those of arbuscular mycorrhizal(AM)species despite there being no significant difference between plants with different leaf types(Simple leaves(SL)vs.Compound leaves(CL)).From the hillside to the peak,both at the community level and at the species level,theδ^(13)C values of leaves and iWUE values of plants exhibited an upward trend.The regression analysis revealed that leaf-scale iWUE was significantly negatively correlated with soil water content and significantly positively correlated with leaf phosphorus content.The findings indicated that leaf carbon isotope fractionation and corresponding iWUE can be influenced by life form,mycorrhizal type,and soil water availability.These insights provide a deeper understanding of the coupling mechanisms of carbon,water,and nutrients among different functional plant types in subtropical forests,and offer insights into predicting plant adaptability under climate change.
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 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.
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the National Natural Science Foundation of China(No.21978183)。
文摘In this work,a modification method of H_(3)PO_(4)plus H_(2)O_(2)(PHP)was introduced to targetedly form abundant oxygenated functional groups(OFGs)on biochar,and methylene blue(MB)was employed as a model pollutant for adsorption to reflect the modification performance.Results indicated that parent biochars,especially derived from lower temperatures,substantially underwent oxidative modification by PHP,and OFGs were targetedly produced.Correspondingly,approximately 21.5-fold MB adsorption capacity was achieved by PHP-modified biochar comparing with its parent biochar.To evaluate the compatibility of PHP-modification,coefficient of variation(CV)based on MB adsorption capacity by the biochar from various precursors was calculated,in which the CV of PHP-modified biochars was 0.0038 comparing to0.64 of the corresponding parent biochars.These results suggested that the PHP method displayed the excellent feedstock compatibility on biochar modification.The maximum MB adsorption capacity was454.1 mg/g when the H_(3)PO_(4)and H_(2)O_(2)fraction in PHP were 65.2%and 7.0%;the modification was further intensified by promoting temperature and duration.Besides,average 94.5%H_(3)PO_(4)was recovered after 10-batch modification,implying 1.0 kg H_(3)PO_(4)(85%)in PHP can maximally modify 2.37 kg biochar.Overall,this work offered a novel method to tailor biochar towards OFGs-rich surface for efficient adsorption.
基金partially funded by a grant from the National Council of Research (Argentina) Number 4678 for the project"Insect Biodiversity of the Monte"
文摘Livestock ranching is one of the main productive activities in arid regions of the world.Grazing produces changes in animal as well as plant communities(e.g.richness,abundance and species dominance relationships).Ants are good biological indicators due to the environmental fidelity of some of their community parameters.We described the functional structure of the ant community in the central Monte of Mendoza,Argentina,and examined the effect of grazing using richness,diversity and the functional group scheme.We used pitfall traps to sample ants at a reserve with 30-year cattle exclusion and at an adjacent ranch.Eleven of the 27 recorded species showed significant differences in their abundance and two species were absent at the ranch.While richness and diversity did not reflect these differences,functional groups did.Hot Climate Specialists were more abundant at the ranch while Cryptic Species and Generalized Myrmicinae increased at the reserve.This study supports the utility of the functional group scheme to study the effects of grazing disturbance in ant communities of arid regions.
基金The authors are grateful for the financial support by the Postdoctoral Science Foundation of China （No. 2003034330）the Science Foundation for mld-youth elite of Shandong Province+3 种基金the Nature Science Foundation of Shandong Province （No. Y2005F11 and No. 2005BS11010）the Nature Science Foundation of Yantai Normal University （No. 032912, 20052901, 042920） Educational Project for Postgraduate of Yantai Normal University （No. YD05001）Applied Project of Educational Bureau of Shandong Province （No. J05D03, J04B02）.
文摘Several of new chelating resins containing sulfoxide and heterocyclic functional groups （3-aminopyridine and 2-mercaptobenzothiazole） based on macroporous chloromethylated polystyrene were synthesized and characterized by elemental analysis and infrared spectra. Their adsorption capacities towards Zn^2＋, Cu^2＋, Pb^2＋, Hg^2＋ and Ag^＋ at pH 3.0 and 6.0 were investigated in detail. It was found that the adsorption capacities of the resins containing bis[（3-pyridylaminoethyl）sulfoxide or （2-benzothiazolylthioethyl）sulfoxide for the above ions were higher than that on ones containing single above-mentioned groups.
基金supported by the Key Projects of the National Natural Science Foundation of China (Nos. 51504187, 51774233, and 51704226)Shaanxi Province Industrial Science and Technology Research Project (No. 2016GY-192)the China Postdoctoral Science Foundation (No. 2016-M-590963)
文摘Correlations among free radicals, apparent activation energy, and functional groups during lowtemperature oxidation of Jurassic coal in Northern Shaanxi were investigated by examining three coal samples collected from the Ningtiaota, Jianxin, and Shigetai coal mines. Free radical concentrations at less than 120 ℃ were investigated by electron spin resonance experiments while the thermogravimetric experiments were conducted to analyze apparent activation energies. In addition, Fourier transform infrared spectroscopy was employed to study the spectrum of functional groups generated in coal. The results indicated that, in decreasing order, the apparent activation energies were Shigetai 〉Jianxin 〉 Ningtiaota, indicating that, from 50 to 120 ℃, the Ningtiaota coal sample most easily absorbed and reacted with oxygen while the most resistant was the Shigetai coal sample. Free radical concentrations and line heights increased with increased temperature, and the line width and Lande factor showed irregular fluctuations. Functional group variations were different among these coals, and the phenol and alcohol-associated OHs, carboxyls, and aromatic ring double bonds might have had a major impact on free radical concentrations. These results were meaningful for better consideration and management of coal oxidation at low temperatures.
基金supported by the National Natural Science Foundation of China (No.52006054)the State Key Laboratory of Engines at Tianjin University (No.K2021-05)+1 种基金the European Union’s projects MODALES (No.815189)nPETS (No.954377)
文摘The thermal deactivation of diesel soot particles exerts a significant influence on the control strategy for the regeneration of diesel particulate filters(DPFs).This work focused on the changes in the surface functional groups,carbon chemical state,and graphitization degree during thermal treatment in an inert gas environment at intermediate temperatures of 600℃,800℃,and 1000℃ and explore the chemical species that were desorbed from the diesel soot surface during thermal treatment using a thermogravimetric analyser coupled with a gas-chromatograph mass spectrometer(TGA-GC/MS).The surface functional groups and carbon chemical statewere characterized using Fourier transform infrared spectroscopy(FT-IR)and X-ray photoelectron spectroscopy(XPS).The graphitization degree was evaluated by means of Raman spectroscopy(RS).The concentrations of aliphatic C–H,C–OH,C=O,and O–C=O groups are reduced for diesel soot and carbon black when increasing the thermal treatment temperature,while the sp^(2)/sp^(3) hybridized ratio and graphitization degree enhance.These results provide comprehensive evidence of the decreased reactivity of soot samples.Among oxygenated functional groups,the percentage reduction during thermal treatment is the largest for the O–C=O groups owing to its worst thermodynamic stability.TGA-GC/MS results show that the aliphatic and aromatic chains and oxygenated species would be desorbed from the soot surface during 1000℃ thermal treatment of diesel soot.
