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The nitrogen transformation behavior based on the pyrolysis products of wheat straw
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作者 Shun Guo Yunfei Li +1 位作者 Shengwei Tang Tao Zhang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第7期58-65,共8页
In order to provide basic design parameters for the industrial pyrolysis process,the transformation behavior of nitrogen was investigated using wheat straw as raw material.The distributions of nitrogen in pyrolysis ch... In order to provide basic design parameters for the industrial pyrolysis process,the transformation behavior of nitrogen was investigated using wheat straw as raw material.The distributions of nitrogen in pyrolysis char,oil,and gas were obtained and the nitrogenous components in the products were analyzed systematically by X-ray photoelectron spectroscopy(XPS),pyrolysis-gas chromatography/mass spectrometry(Py-GC/MS)and thermogravimetric-Fourier transform infrared spectrometry(TG-FTIR).The nitrogen distribution ranges of the pyrolysis char,oil,and gas were 37.34%–54.82%,32.87%–40.94%and 10.20%–28.83%,respectively.More nitrogen was retained in char at lower pyrolysis temperature and the nitrogen distribution of oil was from rise to decline with increasing temperature.The most abundant N-containing compounds in three-phase products were pyrrole-N,amines,and HCN,respectively.In addition,the transformation mechanism of nitrogen from wheat straw to pyrolysis products was concluded. 展开更多
关键词 PYROLYSIS nitrogen transformation Wheat straw Py-GC/MS TG-FTIR
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Transformation of Carbon and Nitrogen by Earthworms in the Decomposition Processes of Broad-leaved Litters 被引量:14
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作者 DONG Weihua YIN Xiuqin 《Chinese Geographical Science》 SCIE CSCD 2007年第2期166-172,共7页
Earthworms are the important constituents in the decayed food web and the main ecological conditioners in the process of decomposition and nutrient mineralization. The transformation of organic carbon (C) and total ni... Earthworms are the important constituents in the decayed food web and the main ecological conditioners in the process of decomposition and nutrient mineralization. The transformation of organic carbon (C) and total nitrogen (N) in the broad-leaved litters ingested by earthworms was researched by means of a laboratory experiment. Experimental samples were collected from broad-leaved Korea Pine mixed forest in Liangshui National Natural Reserve (47°10′50″N, 128°53′20″E) in the northeastern Xiao Hinggan Mountains of Northeast China. The contents of organic C and total N in earthworms, leaf litters and earthworm faeces were analyzed. Results show that the organic C content was in the fol- lowing order: leaf litters>faeces>earthworms, while total N content was contrary to that of the organic C. The organic C contents in the different leaf litters were in the following order: Tilia amurensis>Betula costata>Acer mono, whereas the total N contents in the different leaf litters were: Betula costata>Tilia amurensis>Acer mono. The contents of organic C and total N in the faeces from the different leaf litters were almost consistent with the contents of the leaf litters. After the leaf litters were ingested by earthworms, the organic C, which was transformed to increase earthworms' weights, ac- counted for 3.90%-13.31% of the total ingestion by earthworms, while that in the earthworm faeces accounted for 6.14%-13.70%. The transformed organic C through the other metabolism (e.g., respiration) of earthworms accounted for 75.04%-89.92%. The ingested organic C by earthworms was mostly used for metabolic activities. The N ingested by earthworms was less than organic C. It is estimated that 37.08% of total N was transformed to increase the earthworm's weight, 19.97% into earthworm faeces and 47.86% for the consumption of the earthworm's activities. The earthworms not only increased the content of organic C and total N in the soil, but also decreased the values of C/N in the soil and leaf litters. Earthworms play a major role in the leaf litters' decomposition and transformation. 展开更多
关键词 broad-leaved litters organic carbon total nitrogen EARTHWORM C transformation N transformation
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Carbon Sequestration and Nitrogen Transformation in Soil Cooperated with Organic Composts and Biochar during Corn (<i>Zea mays</i>) Cultivation
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作者 Joung Du Shin 《Journal of Agricultural Chemistry and Environment》 2015年第4期96-101,共6页
Background: Objectives of this study were to investigate changes of soil carbon contents and to evaluate N mineralization and nitrification rates in soils cooperated with organic composts and biochar during the 2nd ye... Background: Objectives of this study were to investigate changes of soil carbon contents and to evaluate N mineralization and nitrification rates in soils cooperated with organic composts and biochar during the 2nd year corn cultivation. Methods and Results: For the experiment, the soil texture used in this study was clay loam. Application rates of chemical fertilizer were 480-150- 260 kg/ha (N-P2O5-K2O) as recommended amount after soil test. Biochar application was 0.2% to soil weight. The soil samples were periodically taken at every 15-day interval during corn cultivation periods. The treatments were consisted of cow compost (CC), pig compost (PC), swine digestate from aerobic digestion system (AD), and their biochar cooperation. TC contents in treatments cooperated with biochar at harvesting stages were ranged from 0.96% to 1.24%, and its CC applied plot was highest at 1.24%. It was observed that TC contents with biochar treatments were higher than the compost treatment only. Therefore, it was observed to be carbon sequestration into corn field cooperated with biochar. For nitrogen transformation in soil cooperated with organic composts and biochar, net mineralization rates were dramatically decreased at 44 days after sowing, but nitrification rates were abruptly increased at 73 days after sowing. For N mineralization and nitrification rates, it was shown that they were generally low in the soil cooperated with biochar as compared to the only application plots of different organic composts. Also, it was observed to be highest in the application plot of pig compost manure. Conclusion: Overall, application of biochar in the cropland could be an important role for mitigation of greenhouse gas as well as carbon sequestration. 展开更多
关键词 BIOCHAR carbon Sequestration nitrogen Mineralization and NITRIFICATION Organic COMPOSTS
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Microfluidic-oriented synthesis of enriched iridium nanodots/carbon architecture for robust electrocatalytic nitrogen fixation 被引量:1
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作者 Hengyuan Liu Xingjiang Wu +2 位作者 Yuhao Geng Xin Li Jianhong Xu 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第3期544-555,共12页
Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless by-... Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless by-products.However,the chemical inertness of nitrogen and poor activated capacity on catalyst surface usually produce low ammonia yield and faradic efficiency.Herein,the microfluidic technology is proposed to efficiently fabricate enriched iridium nanodots/carbon architecture.Owing to in-situ co-precipitation reaction and microfluidic manipulation,the iridium nanodots/carbon nanomaterials possess small average size,uniform dispersion,high conductivity and abundant active sites,producing good proton activation and rapid electrons transmission and moderate adsorption/desorption capacity.As a result,the as-prepared iridium nanodots/carbon nanomaterials realize large ammonia yield of 28.73 μg h^(-1) cm^(-2) and faradic efficiency of 9.14%in KOH solution.Moreover,the high ammonia yield of 11.21 μg h^(-1) cm^(-2) and faradic efficiency of 24.30%are also achieved in H_(2)SO_(4) solution.The microfluidic method provides a reference for large-scale fabrication of nano-sized catalyst materials,which may accelerate the progress of electrocatalytic NRR in industrialization field. 展开更多
关键词 Iridium nanodots carbon Microfluidic technology Efficient synthesis Electrocatalytic nitrogen fixation
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Leaching and Transformation of Nitrogen Fertilizers in Soil After Application of N with Irrigation: A Soil Column Method 被引量:59
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作者 ZHOU Jian-Bin XI Jin-Gen +1 位作者 CHEN Zhu-Jun LI Sheng-Xiu 《Pedosphere》 SCIE CAS CSCD 2006年第2期245-252,共8页
A soil column method was used to compare the effect of drip fertigation (the application of fertilizer through drip irrigation systems, DFI) on the leaching loss and transformation of urea-N in soil with that of surfa... A soil column method was used to compare the effect of drip fertigation (the application of fertilizer through drip irrigation systems, DFI) on the leaching loss and transformation of urea-N in soil with that of surface fertilization combined with flood irrigation (SFI), and to study the leaching loss and transformation of three kinds of nitrogen fertilizers (nitrate fertilizer, ammonium fertilizer, and urea fertilizer) in two contrasting soils after the fertigation. In comparison to SFI, DFI decreased leaching loss of urea-N from the soil and increased the mineral N (NH4+-N + NO3- -N) in the soil. The N leached from a clay loam soil ranged from 5.7% to 9.6% of the total N added as fertilizer, whereas for a sandy loam soil they ranged between 16.2% and 30.4%. Leaching losses of mineral N were higher when nitrate fertilizer was used compared to urea or ammonium fertilizer. Compared to the control (without urea addition), on the first day when soils were fertigated with urea, there were increases in NH4+-N in the soils. This confirmed the rapid hydrolysis of urea in soil during fertigation. NH4+-N in soils reached a peak about 5 days after fertigation, and due to nitrification it began to decrease at day 10. After applying NH4+-N fertilizer and urea and during the incubation period, the mineral nitrogen in the soil decreased. This may be related to the occurrence of NH4+-N fixation or volatilization in the soil during the fertigation process. 展开更多
关键词 FERTIGATION irrigation method N leaching N transformation nitrogen fertilizer
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Kinetics of bainite-to-austenite transformation during continuous reheating in low carbon microalloyed steel 被引量:5
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作者 Ming Chang Hao Yu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2013年第5期427-432,共6页
A dilatometer was used to study the kinetics of bainite-to-austenite transformation in low carbon microalloyed steel with the initial microstructure of bainite during the continuous reheating process. The bainite-to-a... A dilatometer was used to study the kinetics of bainite-to-austenite transformation in low carbon microalloyed steel with the initial microstructure of bainite during the continuous reheating process. The bainite-to-austenite trans- formation was observed to take place in two steps at low heating rate. The first step is the dissolution of bainite, and the second one is the remaining bainite-to-austenite transformation controlled by a dissolution process. The calculation result of the kinetics of austenite formation shows that the two steps occur by diffusion at low heating rate. However, at high heating rate the bainite-to-austenite transformation occurs in a single step, and the process is mainly dominated by shear. The growth rate of austenite reaches the maximum at about 835℃ at different heating rates and the growth rate of austenite as a function of temperature increases with the increase in heating rate. 展开更多
关键词 low carbon steel MICROALLOYING BAINITE AUSTENITE phase transformations REHEATING KINETICS
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INFLUENCE OF HOT DEFORMATION ON CONTINUOUSCOOLING BAINITIC TRANSFORMATION IN A LOWCARBON STEEL 被引量:4
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作者 Z.D.Wang J.B.Qu +1 位作者 X.H.Liu G.D.Wang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1998年第2期121-127,共7页
The influence of hot deformation conditions on continuous cooling bainitic transformation has been investigated for a low carbon microalloyed steel. The CCT diagrams show that deformation in unrecrpstallized austcnite... The influence of hot deformation conditions on continuous cooling bainitic transformation has been investigated for a low carbon microalloyed steel. The CCT diagrams show that deformation in unrecrpstallized austcnite ation can accelerate transformation process. Bainitic transformation in intermediate transformation temperature region is prominent, and the proeutectoid polygonal ferrite transformation at evelated high temperature is suppressed. According to optical and TEM analyses, low carbon bainitic ferrite is characterized by granular and lathlike ferrite, based on the cooling rate and deformation conditions. For nondeformation, groaps of coarse parallel ferrite lath form from the prior austenite grain boundaries with the same crystallographic orientation. For heavy deformaton, cell structure within the austenite grains due to the high dislocation density formed, which provides more nucleation sites for bainite ferrite. So deformation can discontinue the growth of ferrite laths and decrease the length of ferrite laths. 展开更多
关键词 BAINITE continuous cooling transformation low carbon steel DEFORMATION
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DEFORMATION ENHANCED FERRITE TRANSFORMATION IN PLAIN LOW CARBON STEEL 被引量:7
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作者 Z.Q. Sun, W Y. Yang, A.M. Hu and P. Yang (State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China) (School of Material Science and Engineering, University of Science and Technology Beijin 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2001年第2期115-121,共7页
The microstructure evolution during deformation enhanced transformation of undercooled austenite of a plain low carbon steel has been investigated by means of hot compression simulation experiment under various condit... The microstructure evolution during deformation enhanced transformation of undercooled austenite of a plain low carbon steel has been investigated by means of hot compression simulation experiment under various conditions of strain rate, deformation temperature and strain. The effect of austenite grain size on the strain enhanced ferrite transformation has been studied. The ferrite dynamic recrystallization involved in successive hot deformation has been explored. 展开更多
关键词 deformation enhanced transformation undercooled austenite.plain low carbon steel microstructure refinement
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Effect of Rare Earths on Fractionation and Transformation of Soil Available Nitrogen 被引量:3
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作者 丁士明 梁涛 +2 位作者 张自立 孙琴 张朝生 《Journal of Rare Earths》 SCIE EI CAS CSCD 2003年第5期582-586,共5页
The effect of rare earths (RE) on fractionation and transformation of available nitrogen in a yellow cinnamon soil was studied with soil cultivation. The results show that under the dry condition, when the extraneous... The effect of rare earths (RE) on fractionation and transformation of available nitrogen in a yellow cinnamon soil was studied with soil cultivation. The results show that under the dry condition, when the extraneous RE are added to the soil, both concentrations of soil ammonium N and hydrolysable N increase, and the concentrations of soil nitric N decrease. The concentrations of soil available N increase with the increase of RE concentrations in soils when the RE concentrations are low, but it decreases with the increase of high RE concentrations in soils. The NOEC (no observed effect concentration) of the extraneous RE to available N in the soils is 443.8 mg·kg -1 . Under the inundated condition, low RE concentrations in soil has no significant effect on soil ammonium N and hydrolysable N. However, when the soil RE concentrations are high, both of them decrease with the increase of RE concentrations. The NOEC of the extraneous RE to soil ammonium N and hydrolysable N are 171.2 and 256.9 mg·kg -1 , respectively. 展开更多
关键词 PEDOLOGY nitrogen transformation yellow cinnamon soil rare earths
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Nitrogen transformations during pig manure composting 被引量:2
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作者 HUANG Guo-feng WU Qi-tang +1 位作者 LI Fang-bai WONG J.W.C 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2001年第4期401-405,共5页
Composting is now suggested as one of the environmentally and friendly alternative method for disposal of solid organic wastes, as it leads to minimization, stabilization, and utilization of organic waste. Transformat... Composting is now suggested as one of the environmentally and friendly alternative method for disposal of solid organic wastes, as it leads to minimization, stabilization, and utilization of organic waste. Transformations of nitrogen were investigated in co-composting of pig manure with different amendments, such as sawdust and leaves. Samples were analyzed for pH, total-N, soluble NH4-N, soluble NO3-N and soluble organic-N. The total-N increased after 63 days of composting, as well as the soluble NO3-N and soluble organic-N. Soluble NH4,-N increased significantly and showed peak values at day 7, thereafter decreased sharply and gradually to lower levels. Seed germination index (GI) showed that co-composting of pig manure with sawdust reached maturity after 49 days of composting, while co-composting of pig manure with sawdust and leases required shorter time for 35 days. Soluble NH4-N was significantly negatively ( P < 0.05) , while soluble NO3-N and soluble organic-N were significantly positively ( P < 0.05), correlated with seed germination index (GI). Addition of leaves in co-composting of pig manure with sawdust had no significant impacts on nitrogen transformations, but it was beneficial for maturity of pig manure compost. 展开更多
关键词 pig manure COMPOSTING nitrogen transformation MATURITY
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Effect of silicon and prior deformation of austenite on isothermal transformation in low carbon steels 被引量:2
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作者 Minghui CAI Hua DING +1 位作者 Jiansu ZHANG Long LI 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2009年第2期100-109,共10页
Isothermal transformation (TTT) behavior of the low carbon steels with two Si contents (0.50 wt pct and 1.35 wt pct) was investigated with and without the prior deformation. The results show that Si and the prior ... Isothermal transformation (TTT) behavior of the low carbon steels with two Si contents (0.50 wt pct and 1.35 wt pct) was investigated with and without the prior deformation. The results show that Si and the prior deformation of the austenite have significant effects on the transformation of the ferrite and bainite. The addition of Si refines the ferrite grains, accelerates the polygonal ferrite transformation and the formation of M/A constituents, leading to the improvement of the strength. The ferrite grains formed under the prior deformation of the austenite become more homogeneous and refined. However, the influence of deformation on the tensile strength of both steels is dependent on the isothermal temperatures. Thermodynamic calculation indicates that Si and prior deformation reduce the incubation time of both ferrite and bainite transformation, but the effect is weakened by the decrease of the isothermal temperatures. 展开更多
关键词 Low carbon steel Si content Prior deformation of austenite Ferrite transformation Bainite transformation
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Changes in the activities of key enzymes and the abundance of functional genes involved in nitrogen transformation in rice rhizosphere soil under different aerated conditions 被引量:4
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作者 XU Chun-mei XIAO De-shun +4 位作者 CHEN Song CHU Guang LIU Yuan-hui ZHANG Xiu-fu WANG Dan-ying 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第3期923-934,共12页
Soil microorganisms play important roles in nitrogen transformation. The aim of this study was to characterize changes in the activity of nitrogen transformation enzymes and the abundance of nitrogen function genes in... Soil microorganisms play important roles in nitrogen transformation. The aim of this study was to characterize changes in the activity of nitrogen transformation enzymes and the abundance of nitrogen function genes in rhizosphere soil aerated using three different methods(continuous flooding(CF), continuous flooding and aeration(CFA), and alternate wetting and drying(AWD)). The abundances of amoA ammonia-oxidizing archaea(AOA) and ammonia-oxidizing bacteria(AOB), nirS, nirK, and nifH genes, and the activities of urease, protease, ammonia oxidase, nitrate reductase, and nitrite reductase were measured at the tillering(S1), heading(S2), and ripening(S3) stages. We analyzed the relationships of the aforementioned microbial activity indices, in addition to soil microbial biomass carbon(MBC) and soil microbial biomass nitrogen(MBN), with the concentration of soil nitrate and ammonium nitrogen. The abundance of nitrogen function genes and the activities of nitrogen invertase in rice rhizosphere soil were higher at S2 compared with S1 and S3 in all treatments. AWD and CFA increased the abundance of amoA and nifH genes, and the activities of urease, protease, and ammonia oxidase, and decreased the abundance of nirS and nirK genes and the activities of nitrate reductase and nitrite reductase, with the effect of AWD being particularly strong. During the entire growth period, the mean abundances of the AOA amoA, AOB amoA, and nifH genes were 2.9, 5.8, and 3.0 higher in the AWD treatment than in the CF treatment, respectively, and the activities of urease, protease, and ammonia oxidase were 1.1, 0.5, and 0.7 higher in the AWD treatment than in the CF treatment, respectively. The abundances of the nirS and nirK genes, and the activities of nitrate reductase and nitrite reductase were 73.6, 84.8, 10.3 and 36.5% lower in the AWD treatment than in the CF treatment, respectively. The abundances of the AOA amoA, AOB amoA, and nifH genes were significantly and positively correlated with the activities of urease, protease, and ammonia oxidase, and the abundances of the nirS and nirK genes were significantly positively correlated with the activities of nitrate reductase. All the above indicators were positively correlated with soil MBC and MBN. In sum, microbial activity related to nitrogen transformation in rice rhizosphere soil was highest at S2. Aeration can effectively increase the activity of most nitrogen-converting microorganisms and MBN, and thus promote soil nitrogen transformation. 展开更多
关键词 rhizosphere aeration gene abundance enzyme activities soil microbial biomass carbon soil microbial nitrogen
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Effects of nitrogen deposition on the carbon budget and water stress in Central Asia under climate change
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作者 HAN Qifei XU Wei LI Chaofan 《Journal of Arid Land》 SCIE CSCD 2024年第8期1118-1129,共12页
Atmospheric deposition of nitrogen(N)plays a significant role in shaping the structure and functioning of various terrestrial ecosystems worldwide.However,the magnitude of N deposition on grassland ecosystems in Centr... Atmospheric deposition of nitrogen(N)plays a significant role in shaping the structure and functioning of various terrestrial ecosystems worldwide.However,the magnitude of N deposition on grassland ecosystems in Central Asia still remains highly uncertain.In this study,a multi-data approach was adopted to analyze the distribution and amplitude of N deposition effects in Central Asia from 1979 to 2014 using a process-based denitrification decomposition(DNDC)model.Results showed that total vegetation carbon(C)in Central Asia was 0.35(±0.09)Pg C/a and the averaged water stress index(WSI)was 0.20(±0.02)for the whole area.Increasing N deposition led to an increase in the vegetation C of 65.56(±83.03)Tg C and slightly decreased water stress in Central Asia.Findings of this study will expand both our understanding and predictive capacity of C characteristics under future increases in N deposition,and also serve as a valuable reference for decision-making regarding water resources management and climate change mitigation in arid and semi-arid areas globally. 展开更多
关键词 carbon dynamics climate change grassland ecosystems nitrogen deposition water stress index
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Enhanced stability of nitrogen-doped carbon-supported palladium catalyst for oxidative carbonylation of phenol
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作者 Xiaojing Liu Ruohan Zhao +4 位作者 Hao Zhao Zhimiao Wang Fang Li Wei Xue Yanji Wang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第1期19-28,共10页
Enhancing the stability of supported noble metal catalysts emerges is a major challenge in both science and industry.Herein,a heterogeneous Pd catalyst(Pd/NCF)was prepared by supporting Pd ultrafine metal nanoparticle... Enhancing the stability of supported noble metal catalysts emerges is a major challenge in both science and industry.Herein,a heterogeneous Pd catalyst(Pd/NCF)was prepared by supporting Pd ultrafine metal nanoparticles(NPs)on nitrogen-doped carbon;synthesized by using F127 as a stabilizer,as well as chitosan as a carbon and nitrogen source.The Pd/NCF catalyst was efficient and recyclable for oxidative carbonylation of phenol to diphenyl carbonate,exhibiting higher stability than Pd/NC prepared without F127 addition.The hydrogen bond between chitosan(CTS)and F127 was enhanced by F127,which anchored the N in the free amino group,increasing the N content of the carbon material and ensuring that the support could provide sufficient N sites for the deposition of Pd NPs.This process helped to improve metal dispersion.The increased metal-support interaction,which limits the leaching and coarsening of Pd NPs,improves the stability of the Pd/NCF catalyst.Furthermore,density functional theory calculations indicated that pyridine N stabilized the Pd^(2+)species,significantly inhibiting the loss of Pd^(2+)in Pd/NCF during the reaction process.This work provides a promising avenue towards enhancing the stability of nitrogen-doped carbon-supported metal catalysts. 展开更多
关键词 Supported Pd catalyst N-doped carbon Amphiphilic triblock copolymer Pyridinic nitrogen STABILITY
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Correlation and Pathway Analysis of the Carbon,Nitrogen,and Phosphorus in Soil-Microorganism-Plant with Main Quality Components of Tea(Camellia sinensis)
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作者 Chun Mao Ji He +3 位作者 Xuefeng Wen Yangzhou Xiang Jihong Feng Yingge Shu 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第3期487-502,共16页
The contents of carbon(C),nitrogen(N),and phosphorus(P)in soil-microorganisms-plant significantly affect tea quality by altering the main quality components of tea,such as tea polyphenols,amino acids,and caffeine.Howev... The contents of carbon(C),nitrogen(N),and phosphorus(P)in soil-microorganisms-plant significantly affect tea quality by altering the main quality components of tea,such as tea polyphenols,amino acids,and caffeine.However,few studies have quantified the effects of these factors on the main quality components of tea.The study aimed to explore the interactions of C,N,and P in soil-microorganisms-plants and the effects of these factors on the main quality components of tea by using the path analysis method.The results indicated that(1)The contents of C,N,and P in soil,microorganisms,and tea plants were highly correlated and collinear,and showed significant correlations with the main quality components of tea.(2)Optimal regression equations were established to esti-mate tea polyphenol,amino acid,catechin,caffeine,and water extract content based on C,N,and P contents in soil,microorganisms,and tea plants(R^(2)=0.923,0.726,0.954,0.848,and 0.883,respectively).(3)Pathway analysis showed that microbial biomass phosphorus(MBP),root phosphorus,branch nitrogen,and microbial biomass carbon(MBC)were the largest direct impact factors on tea polyphenol,catechin,water extracts,amino acid,and caffeine content,respectively.Leaf carbon,root phosphorus,and leaf nitrogen were the largest indirect impact factors on tea polyphenol,catechin,and water extract content,respectively.Leaf carbon indirectly affected tea polyphenol content mainly by altering MBP content.Root phosphorus indirectly affected catechin content mainly by altering soil organic carbon content.Leaf nitrogen indirectly affected water extract content mainly by altering branch nitrogen content.The research results provide the scientific basis for reasonable fertilization in tea gardens and tea quality improvement. 展开更多
关键词 Soil-microorganisms-plant system carbon nitrogen PHOSPHORUS tea quality path analysis
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Effects of inherent alkali and alkaline earth metals on nitrogen transformation during steam gasification of Shengli lignite 被引量:2
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作者 Panpan Zheng Yonggang Wang +4 位作者 Chen Liu Weijie Guo Lei Bai Xiao Hu Xiongchao Lin 《International Journal of Coal Science & Technology》 EI 2019年第2期197-206,共10页
This work evaluated the effects of inherent alkali and alkaline earth metals on nitrogen transformation during steam gasification of Shengli lignite at the temperature of 873-1173 K in a fluidized-bed/fixed-bed quartz... This work evaluated the effects of inherent alkali and alkaline earth metals on nitrogen transformation during steam gasification of Shengli lignite at the temperature of 873-1173 K in a fluidized-bed/fixed-bed quartz reactor. The results indicated that the alkali metal Na and alkaline earth metals Ca, Mg in coal have different effects on inherent nitrogen transformation to NH3, HCN and char-N during the lignite steam gasification. Specifically during the steam gasification of Shengli lignite, Na and Ca, Mg not only catalyze the inherent nitrogen conversions to NH3, but also promote the secondary reactions of the nascent char-N as well as the generation of NH3 from the generated HCN, meanwhile they also inhibited the inherent nitrogen conversion to HCN and char-N. The presence of Na, Ca and Mg hindered the formation of oxidized nitrogen (N-X) functional groups, but enhanced pyridinic nitrogen (N-6) and quaternary nitrogen's (N-Q) formation in char. 展开更多
关键词 LIGNITE Steam GASIFICATION nitrogen transformation ALKALI metal-Alkaline earth METAL
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Elucidating the role of embedding dispersed cobalt sites in nitrogen-doped carbon frameworks in Si-based anodes for stable and superior storage
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作者 Yueying Chen Ping Li +8 位作者 Mianying Huang Chunlei Wu Qianhong Huang Tingyang Xie Xiaoming Lin Akif Zeb Yongbo Wu Zhiguang Xu Yuepeng Cai 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第11期180-195,共16页
Unsatisfactory conductivity and volume effects have hindered the commercial application of siliconbased materials as advanced anode materials for high-performance lithium-ion batteries. Herein, nitrogen doped carbon s... Unsatisfactory conductivity and volume effects have hindered the commercial application of siliconbased materials as advanced anode materials for high-performance lithium-ion batteries. Herein, nitrogen doped carbon silicon matrix composite with atomically dispersed Co sites(Si/Co-N-C) is obtained via the design of the frame structure loaded with nano-components and the multi-element hybrid strategy. Co atoms are uniformly fixed to the N-C frame and tightly packed with nanoscale silicon particles as an activation and protection building block. The mechanism of the N-C framework of loaded metal Co in the Si alloying process is revealed by electrochemical kinetic analysis and ex situ characterization tests.Impressively, the nitrogen-doped Co site activates the intercalation of the outer carbon matrix to supplement the additional capacity. The Co nanoparticles with high conductivity and support enhance the conductivity and structural stability of the composite, accelerating the Li^(+)/Na^(+) diffusion kinetics. Density functional theory(DFT) calculation confirms that the hetero-structure Si/Co-N-C adjusts the electronic structure to obtain good lithium-ion adsorption energy, reduces the Li^(+)/Na^(+) migration energy barrier.This work provides meaningful guidance for the development of high-performance metal/non-metal modified anode materials. 展开更多
关键词 Co nanoparticles nitrogen doped carbon Silicon Lithium/sodium storage Metal-organic frameworks(MOFs)
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Effects of tree size and organ age on variations in carbon,nitrogen,and phosphorus stoichiometry in Pinus koraiensis
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作者 Yanjun Wang Guangze Jin Zhili Liu 《Journal of Forestry Research》 SCIE EI CAS CSCD 2024年第3期155-165,共11页
Carbon(C),nitrogen(N),and phosphorus(P)are of fundamental importance for growth and nutrient dynamics within plant organs and deserve more attention at regional to global scales.However,our knowledge of how these nutr... Carbon(C),nitrogen(N),and phosphorus(P)are of fundamental importance for growth and nutrient dynamics within plant organs and deserve more attention at regional to global scales.However,our knowledge of how these nutrients vary with tree size,organ age,or root order at the individual level remains limited.We determined C,N,and P contents and their stoichiometric ratios(i.e.,nutrient traits)in needles,branches,and fine roots at different organ ages(0-3-year-old needles and branches)and root orders(1st-4th order roots)from 64 Pinus koraiensis of varying size(Diameter at breast height ranged from 0.3 to 100 cm)in northeast China.Soil factors were also measured.The results show that nutrient traits were regulated by tree size,organ age,or root order rather than soil factors.At a whole-plant level,nutrient traits decreased in needles and fine roots but increased in branches with tree size.At the organ level,age or root order had a negative effect on C,N,and P and a positive effect on stoichiometric ratios.Our results demonstrate that nutrient variations are closely related to organ-specific functions and ecophysiological processes at an individual level.It is suggested that the nutrient acquisition strategy by younger trees and organ fractions with higher nutrient content is for survival.Conversely,nutrient storage strategy in older trees and organ fractions are mainly for steady growth.Our results clarified the nutrient utilization strategies during tree and organ ontogeny and suggest that tree size and organ age or root order should be simultaneously considered to understand the complexities of nutrient variations. 展开更多
关键词 Tree size Organ age(or root order) carbon(C) nitrogen(N) Phosphorus(P) Pinus koraiensis
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Super long-range diffusion of carbon during proeutectoid ferrite transformation 被引量:2
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作者 ZHANG Suo-quan JIAO Si-hai +3 位作者 DING Jian-hua WAN Di LIU Zhen-yu WANG Guo-dong 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第3期560-566,共7页
In order to explore the possible diffusion distance of carbon during proeutectoid ferrite transformation, a slow cooling test of low carbon steel was carried out under vacuum of the thermal simulator. The microstructu... In order to explore the possible diffusion distance of carbon during proeutectoid ferrite transformation, a slow cooling test of low carbon steel was carried out under vacuum of the thermal simulator. The microstructure and thermal expansion curve were discussed and the carbon concentration inside the sample was measured. The ferrite layer of about 450 μm thickness was obtained without pearlite on the surface of the sample in the microstructure. The thermal expansion curve shows that the ferrite layer without pearlite is formed during the local phase transformation, which is followed by the global transformation. The carbon concentration in the core of the sample (0.061%) is significantly higher than that of the bulk material (0.054%). All results show that carbon has long-range diffusion from the outer layer to the inner layer of the sample. The transformation is predominantly interface-controlled mode during local transformation, and the interface migration rate is about 2.25 μm/s. 展开更多
关键词 low carbon steel local transformation super long-rang diffusion interface-controlled mode
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Effects of phytoplankton community and interaction between environmental variables on nitrogen uptake and transformations in an urban river 被引量:1
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作者 Jing YANG Haiguang PEI +5 位作者 Junping LÜ Qi LIU Fangru NAN Xudong LIU Shulian XIE Jia FENG 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2022年第3期1012-1026,共15页
Phytoplankton are not only the main bearer of the nitrogen cycle,but also a key link driving nitrogen cycle.However,most phytoplankton cannot directly use N_(2),and they must uptake nitrogenous nutrients(ammonium,nitr... Phytoplankton are not only the main bearer of the nitrogen cycle,but also a key link driving nitrogen cycle.However,most phytoplankton cannot directly use N_(2),and they must uptake nitrogenous nutrients(ammonium,nitrate,and urea)to meet their photosynthesis needs.We examined the uptake characteristics of several nitrogenous substrates using stable isotope technique and identifi ed the potential nitrogen transformations in the Fenhe River.Results revealed that spring phytoplankton community composed of mainly Fragilaria,Ulothrix,Microcystis,and Synedra.Urea can meet the spring partial nitrogen requirement of phytoplankton.The large uptake rate of urea depended on urease,chlorophyll a,and nitrate concentrations as shown in random forest models.Cyanobacteria explained more than 42.8%of the total abundance at all sites in summer.Upstream was dominated by Actinastrum,and Chlorella was relevant in the downstream section.The uptake rates of ammonium were higher than those of nitrate and urea.In addition,the random forest model demonstrated that ammonium,urease,and dissolved oxygen(DO)were the major contributors to the ammonium uptake rates.Ammonium was taken up preferentially in autumn and phytoplankton(Cyclotella,Chlorella,and Pseudanabaena)appeared to be able to respond to changes in nitrogen forms by adjusting their community composition.Structural equation models demonstrated that temperature-induced changes in DO directly affected the transformations of different forms of nitrogen.At the same time,dissolved organic carbon can directly act on nutrients and then indirectly affect enzyme activity.There were great diff erences in the positive and negative effects of different paths in the process of nitrate reduction to nitrite and then reduction to ammonium in time and space.These findings provide a better understanding of the underlying mechanism of nitrogen uptake and the influences of interaction between environmental variables on nitrogen transformations in urban river ecosystems. 展开更多
关键词 PHYTOPLANKTON environmental variables nitrogen uptake transformation urban river
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