The endpoint carbon content in the converter is critical for the quality of steel products,and accurately predicting this parameter is an effective way to reduce alloy consumption and improve smelting efficiency.Howev...The endpoint carbon content in the converter is critical for the quality of steel products,and accurately predicting this parameter is an effective way to reduce alloy consumption and improve smelting efficiency.However,most scholars currently focus on modifying methods to enhance model accuracy,while overlooking the extent to which input parameters influence accuracy.To address this issue,in this study,a prediction model for the endpoint carbon content in the converter was developed using factor analysis(FA)and support vector machine(SVM)optimized by improved particle swarm optimization(IPSO).Analysis of the factors influencing the endpoint carbon content during the converter smelting process led to the identification of 21 input parameters.Subsequently,FA was used to reduce the dimensionality of the data and applied to the prediction model.The results demonstrate that the performance of the FA-IPSO-SVM model surpasses several existing methods,such as twin support vector regression and support vector machine.The model achieves hit rates of 89.59%,96.21%,and 98.74%within error ranges of±0.01%,±0.015%,and±0.02%,respectively.Finally,based on the prediction results obtained by sequentially removing input parameters,the parameters were classified into high influence(5%-7%),medium influence(2%-5%),and low influence(0-2%)categories according to their varying degrees of impact on prediction accuracy.This classi-fication provides a reference for selecting input parameters in future prediction models for endpoint carbon content.展开更多
Carbon can change the phase components of low-density steels and influence the mechanical properties.In this study,a new method to control the carbon content and avoid the formation ofδ-ferrite by decarburization tre...Carbon can change the phase components of low-density steels and influence the mechanical properties.In this study,a new method to control the carbon content and avoid the formation ofδ-ferrite by decarburization treatment was proposed.The microstructural changes and mechanical characteristics with carbon content induced by decarburization were systematically examined.Crussard-Jaoul(C-J)analysis was employed to examine the work hardening characteristics during the tensile test.During decarburization by heat treatments,the carbon content within the austenite phase decreased,while Mn and Al were almost unchanged;this made the steel with full austenite transform into the austenite and ferrite dual phase.Meanwhile,(Ti,V)C carbides existed in both matrix phase and the mole fraction almost the same.In addition,the formation of other carbides restrained.Carbon loss induced a decrease in strength due to the weakening of the carbon solid solution.For the steel with the single austinite,the deformation mode of austenite was the dislocation planar glide,resulting in the formation of microbands.For the dual-phase steel,the deformation occurred by the dislocation planar glide of austenite first,with the increase in strain,the cross slip of ferrite took place,forming dislocation cells in ferrite.At the late stage of deformation,the work hardening of austinite increased rapidly,while that of ferrite increased slightly.展开更多
The effects of cryogenic treatment(CT)and tempering-cryogenic treatment(TCT)on the microstructure and properties of coarse-grained WC-10Co cemented carbides with different carbon contents were researched.The binder ph...The effects of cryogenic treatment(CT)and tempering-cryogenic treatment(TCT)on the microstructure and properties of coarse-grained WC-10Co cemented carbides with different carbon contents were researched.The binder phase,WC mean grain sizes,W solubility in the binder,relative magnetic s aturation,densities,hardness,wear resistance and second phase precipitation of cemented carbides with different heat treatments were discussed.The results show that there are significant changes of microstructure and properties in the samples with CT and TCT,especially due to the precipitation of metastable nanoparticles W_(x)Co_(y)C_(z) in the binder during the heat treatments of CT and TCT.With the simultaneous combination of microstructure and nanoparticle-reinforced binder,a dramatically improved combination of hardness and wear resistance of the samples after TCT has been achieved.展开更多
The coating layers of Tri-structural Isotropic Particles(TRISO)serve to protect the kernel and act as barriers to fission products.Sintering aids in the silicon carbide matrix variably react with TRISO coating layers,...The coating layers of Tri-structural Isotropic Particles(TRISO)serve to protect the kernel and act as barriers to fission products.Sintering aids in the silicon carbide matrix variably react with TRISO coating layers,leading to the destruction of the coating layers.Investigating how carbon content affects element diffusion in silicon carbide-based TRISO composite fuel is of great significance for predicting reactor safety.In this study,silicon carbide-based TRISO composite fuels with different carbon contents were prepared by adding varying amounts of phenolic resin to the silicon carbide matrix.X-ray Diffraction(XRD)and Scanning Electron Microscopy(SEM)were employed to characterize the phase composition,morphology,and microstructure of the composite fuels.The elemental content in each coating layer of TRISO was quantified using Energy-Dispersive X-ray Spectroscopy(EDS).The results demonstrated that the addition of phenolic resin promoted the uniform distribution of sintering aids in the silicon carbide matrix.The atomic percentage(at.%)of aluminum(Al)in the pyrolytic carbon layer of the TRISO particles reached its lowest value of 0.55%when the phenolic resin addition was 1%.This is because the addition of phenolic resin caused the Al and silicon(Si)in the matrix to preferentially react with the carbon in the phenolic resin to form a metastable liquid phase,rather than preferentially consuming the pyrolytic carbon in the outer coating layer of the TRISO particles.The findings suggest that carbon addition through phenolic resin incorporation can effectively mitigate the deleterious reactions between the TRISO coating layers and sintering aids,thereby enhancing the durability and safety of silicon carbide-based TRISO composite fuels.展开更多
Global warming has become an increasing concern, and using soil as a carbon sink to sequester carbon dioxide has attracted much attention in recent years. In this study, soil organic carbon (SOC) content and organic c...Global warming has become an increasing concern, and using soil as a carbon sink to sequester carbon dioxide has attracted much attention in recent years. In this study, soil organic carbon (SOC) content and organic carbon density were estimated based on a soil survey of a small landscape in Dongguan, South China, with spatial heterogeneity of SOC distribution and the impacts of land-use patterns on soil organic carbon content assessed. Field sampling was carried out based on a 150 m×150 m grid system overlaid on the topographic map of the study area and samples were collected in three 20-cm layers to a depth of 60 cm. Spatial variability in the distribution of SOC was assessed using the Kruskal-Wallis test. Results showed that SOC in the topsoil layer (0-20 cm) was not much higher or even lower in some sites than the underlying layers, and except for the two sites covered with natural woodland, it did not exhibit a pronounced vertical gradient. The difference in both horizontal and vertical distribution of SOC was not statistically significant. However, in the topsoil layer among land-use/land-cover patterns, significant differences (P≤0.05) in SOC distribution existed, indicating that management practices had great impact on SOC content. SOC storage in the study area to a depth of 20, 40, and 60 cm was estimated as 2.13×106 kg, 3.46×106 kg, and 4.61×106 kg, respectively.展开更多
The carbon content of bituminous coal samples was analyzed by laser-induced breakdown spectroscopy. The 266 nm laser radiation was utilized for laser ablation and plasma generation in air. The partial least square met...The carbon content of bituminous coal samples was analyzed by laser-induced breakdown spectroscopy. The 266 nm laser radiation was utilized for laser ablation and plasma generation in air. The partial least square method and the dominant factor bused PLS method were used to improve the measurement accuracy of the carbon content of coal. The results showed that the PLS model could achieve good measurement accuracy, and the dominant factor based PLS model could further improve the measurement accuracy. The coefficient of determination and the root-mean-square error of prediction of the PLS model were 0.97 and 2.19%, respectively; and those values for the dominant factor based PLS model were 0.99 and 1.51%, respectively. The results demonstrated that the 266 nm wavelength could accurately measure the carbon content of bituminous coal.展开更多
Pure WC-6%Co nanosized composite powders were synthesized via a low-temperature method.The effects of carbon source on microstructure characteristic of composite powders were investigated,and the effects of heat-treat...Pure WC-6%Co nanosized composite powders were synthesized via a low-temperature method.The effects of carbon source on microstructure characteristic of composite powders were investigated,and the effects of heat-treatment parameter on carbon content of composite powders were also discussed.The results of SEM and XRD revealed that the carbon decomposing from glucose was more active than carbon black.Therefore,WC-Co nanosized composite powders could be synthesized at 900°C for 1 h under a hydrogen atmosphere.The individual WC grains were bonded together into a long strip under the action of cobalt.The results of carbon analysis revealed that the total carbon content decreased with the increase of the temperature in the range of 800-1000°C.Moreover,the total carbon content and the compounded carbon increased with the increase of the flow rate of H2 in the range of 1.1-1.9 m3/h.展开更多
The effects of finishing rolling temperature and coiling temperature on retained austen-ite were studied for hot-rolled transformation induced plasticity (TRIP) steels with different carbon content. The experimental r...The effects of finishing rolling temperature and coiling temperature on retained austen-ite were studied for hot-rolled transformation induced plasticity (TRIP) steels with different carbon content. The experimental results showed that an appropriate volume fraction of retained austenite from 6% to 11% could be obtained according to the different carbon content less than 0.20% by controlled finishing rolling and coiling for the hot-rolled TRIP steels. It can be concluded that carbon content has a significant effect on the fraction of retained austenite and coiling processing plays stronger role on retaining austenite than fishing rolling processing.展开更多
The thermal conductivity or diffusivity of pearlitic grey irons with various carbon contents is investigated by the laser flash method. The materials are cast in controlled thermal environments and produced in three d...The thermal conductivity or diffusivity of pearlitic grey irons with various carbon contents is investigated by the laser flash method. The materials are cast in controlled thermal environments and produced in three dissimilar cooling rates. The cooling rate together with the carbon content largely influence the thermal conductivity of grey iron. Linear relationships exist between the thermal conductivity and the carbon content,the carbon equivalent and the fraction of former primary solidified austenite transformed into pearlite. The work shows that optimal thermal transport properties are obtained at medium cooling rates. Equations describing the thermal conductivity of pearlite,solidified as pre-eutectic austenite,and the eutectic of grey iron are derived. The thermal conductivity of pearlitic grey iron is modeled at both room temperature and elevated temperature with good accuracy.展开更多
Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)...Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)with a relative high concentration using different kinds of ZVI powders(mainly carbon differences)including reduced Fe,grey cast iron,pig iron,nodular pig iron was carried out.Parameters such as ZVI dosage,type and size affecting on Cr(VI)reduction were firstly examined and grey cast iron was selected as a preferable reducing material,followed by pig iron.Additionally,it was found that the parameters had significant influences on experimental kinetics.Then,morphology and composition of the sample before and after reaction were characterized by SEM,EPMA and XPS analyses to disclose carbon effect on the reducibility.In order to further interpret reaction mechanism,different reaction models were constructed.It was revealed that not only the carbon content could affect the Cr(VI)reduction,but also the carbon structure had an important effect on its reduction.展开更多
The reaction activity of S Zorb sorbents with different sulfur contents was investigated, and the structure and composition of carbon-containing sorbents were characterized by XRD, FT-IR and TG-MS in order to delve in...The reaction activity of S Zorb sorbents with different sulfur contents was investigated, and the structure and composition of carbon-containing sorbents were characterized by XRD, FT-IR and TG-MS in order to delve into the kind and morphology of carbon on the sorbent. Test results have revealed that coke could be deposited on the S Zorb sorbent during the operating process, and the coke content was an important factor influencing the reaction performance of the S Zorb sorbent. Retention of a definite amount of coke on the sorbent while securing the desulfurization activity of the S Zorb sorbent would be conducive to the reduction of octane loss of reaction product.展开更多
Assessing canopy nitrogen content(CNC) and canopy carbon content(CCC) of maize by hyperspectral remote sensing data permits estimating cropland productivity, protecting farmland ecology, and investigating the nitrogen...Assessing canopy nitrogen content(CNC) and canopy carbon content(CCC) of maize by hyperspectral remote sensing data permits estimating cropland productivity, protecting farmland ecology, and investigating the nitrogen and carbon cycles in the atmosphere. This study aimed to assess maize CNC and CCC using canopy hyperspectral information and uninformative variable elimination(UVE). Vegetation indices(VIs) and wavelet functions were adopted for estimating CNC and CCC under varying water and nitrogen regimes. Linear, nonlinear, and partial least squares(PLS) regression models were fitted to VIs and wavelet functions to estimate CNC and CCC, and were evaluated for their prediction accuracy.UVE was used to eliminate uninformative variables, improve the prediction accuracy of the models, and simplify the PLS regression models(UVE-PLS). For estimating CNC and CCC, the normalized difference vegetation index(NDVI, based on red edge and NIR wavebands) yielded the highest correlation coefficients(r > 0.88). PLS regression models showed the lowest root mean square error(RMSE) among all models. However, PLS regression models required nine VIs and four wavelet functions, increasing their complexity. UVE was used to retain valid spectral parameters and optimize the PLS regression models.UVE-PLS regression models improved validation accuracy and resulted in more accurate CNC and CCC than the PLS regression models. Thus, canopy spectral reflectance integrated with UVE-PLS can accurately reflect maize leaf nitrogen and carbon status.展开更多
The in situ Al 2O 3p TiC p/Al composite was fabricated by XD (exothermic dispersion) process in TiO 2 Al C system, and the effect of carbon content on the microstructure of the fabricated composite and the reactive te...The in situ Al 2O 3p TiC p/Al composite was fabricated by XD (exothermic dispersion) process in TiO 2 Al C system, and the effect of carbon content on the microstructure of the fabricated composite and the reactive temperature characteristics had been studied. The results show that carbon content affects the microstructure and reactive temperature of Al 2O 3p TiC p/Al composite greatly. The quantity of TiC phases in the fabricated composites increases, while the Al 3Ti phases reduces with increasing carbon content. And when C/TiO 2 molecular ratio is equal to one, the Al 3Ti phase nearly disappears. High temperature metallurgical field caused by strong exothermic reaction influences the synthetic reaction greatly, and higher synthetic temperature was favorable to the synthesis of Al 2O 3p TiC p reinforce particles.展开更多
The influence of carbon content on the stacking fault energy （SFE） of Fe-20Mn-3Cu twinning-induced plasticity （TWIP） steel was investigated by means of X-ray diffraction peak-shift method and thermodynamic modelin...The influence of carbon content on the stacking fault energy （SFE） of Fe-20Mn-3Cu twinning-induced plasticity （TWIP） steel was investigated by means of X-ray diffraction peak-shift method and thermodynamic modeling. The experimental result indicated that the stacking fault probability decreases with increasing carbon addition, the SFE increases linearly when the carbon content in mass percent is between 0.23 M and 1.41%. The thermody namic calculation results showed that the SFE varied from 22.40 to 29.64 mJ ~ m 2 when the carbon content in mass percent changes from 0.23 % to 1.41%. The XRD analysis revealed that all steels were fully austenitic before and after deformation, which suggested that TWIP effect is the predominant mechanism during the tensile deformation process of Fe-20Mn-3Cu-XC steels.展开更多
The micro structure and mechanical properties of new kind of hot-rolled high strength and high elongation steels with retained austenite were studied by discussing the influence of different carbon content. The resear...The micro structure and mechanical properties of new kind of hot-rolled high strength and high elongation steels with retained austenite were studied by discussing the influence of different carbon content. The research results indicate that carbon content has a significant effect on retaining austenite and consequently resulting in high elongation. Besides, new findings about relationship between carbon content and retained austenite as well as properties were discussed in the paper.展开更多
The total organic carbon content usually determines the hydrocarbon generation potential of a formation.A higher total organic carbon content often corresponds to a greater possibility of generating large amounts of o...The total organic carbon content usually determines the hydrocarbon generation potential of a formation.A higher total organic carbon content often corresponds to a greater possibility of generating large amounts of oil or gas.Hence,accurately calculating the total organic carbon content in a formation is very important.Present research is focused on precisely calculating the total organic carbon content based on machine learning.At present,many machine learning methods,including backpropagation neural networks,support vector regression,random forests,extreme learning machines,and deep learning,are employed to evaluate the total organic carbon content.However,the principles and perspectives of various machine learning algorithms are quite different.This paper reviews the application of various machine learning algorithms to deal with total organic carbon content evaluation problems.Of various machine learning algorithms used for TOC content predication,two algorithms,the backpropagation neural network and support vector regression are the most commonly used,and the backpropagation neural network is sometimes combined with many other algorithms to achieve better results.Additionally,combining multiple algorithms or using deep learning to increase the number of network layers can further improve the total organic carbon content prediction.The prediction by backpropagation neural network may be better than that by support vector regression;nevertheless,using any type of machine learning algorithm improves the total organic carbon content prediction in a given research block.According to some published literature,the determination coefficient(R^(2))can be increased by up to 0.46 after using machine learning.Deep learning algorithms may be the next breakthrough direction that can significantly improve the prediction of the total organic carbon content.Evaluating the total organic carbon content based on machine learning is of great significance.展开更多
Agricultural and forestry biomass can be converted to biochar through pyrolysis gasification,making it a significant carbon source for soil.Applying biochar to soil is a carbon-negative process that helps combat clima...Agricultural and forestry biomass can be converted to biochar through pyrolysis gasification,making it a significant carbon source for soil.Applying biochar to soil is a carbon-negative process that helps combat climate change,sustain soil biodiversity,and regulate water cycling.However,quantifying soil carbon content conventionally is time-consuming,labor-intensive,imprecise,and expensive,making it difficult to accurately measure in-field soil carbon’s effect on storage water and nutrients.To address this challenge,this paper for the first time,reports on extensive lab tests demonstrating non-intrusive methods for sensing soil carbon and related smart biochar applications,such as differentiating between biochar types from various biomass feedstock species,monitoring soil moisture,and biochar water retention capacity using portable microwave and millimeter wave sensors,and machine learning.These methods can be scaled up by deploying the sensor in-field on a mobility platform,either ground or aerial.The paper provides details on the materials,methods,machine learning workflow,and results of our investigations.The significance of this work lays the foundation for assessing carbon-negative technology applications,such as soil carbon content accounting.We validated our quantification method using supervised machine learning algorithms by collecting real soil mixed with known biochar contents in the field.The results show that the millimeter wave sensor achieves high sensing accuracy(up to 100%)with proper classifiers selected and outperforms the microwave sensor by approximately 10%–15%accuracy in sensing soil carbon content.展开更多
New steels with different carbon contents were self-developed by thermo-mechanical controlled processing. The effects of the carbon content and the microstructure on the corrosion properties of new steels were investi...New steels with different carbon contents were self-developed by thermo-mechanical controlled processing. The effects of the carbon content and the microstructure on the corrosion properties of new steels were investigated by immersion test and SEM. The results indicated that the ferrite phase （both the proeutectoid and eutectoid ferrite） dissolved preferentially. Cementite reserved and accumulated on the surface. As carbon content increased, the content of ferrite decreased and cathode/anode area ratio increased. Therefore, the corrosion rate of new steels increased from 0.30 to 0.90 mm/years when the carbon content rose from 0.05 to 0.13 wt%. The corrosion process of new steels was studied using electrochemical impedance spectroscopy experiments during 72 h. It indicated that the impedance modulus IZlo.ol nz of the new steels reduces with the increase of the immersion time. While the corrosion process of the new steel with 0.11 wt% C developed faster than that with 0.07 wt% C, although their IZlo.ol nz was similar at the initial stage.展开更多
WC-10Co nanocrystalline composite powders prepared by spray pyrogenation-continuous reduction and carburization technology were consolidated by vacuum sintering plus hot isostatic pressing （HIP）. Influences of carbo...WC-10Co nanocrystalline composite powders prepared by spray pyrogenation-continuous reduction and carburization technology were consolidated by vacuum sintering plus hot isostatic pressing （HIP）. Influences of carbon content on properties and microstructure of ultrafine WC-10Co cemented carbide were investigated. The results show that the relative density of the ultrafine WC-10Co cemented carbides can reach 99.72%, and the transverse rupture strength （TRS） was higher than 3 890 MPa, Rockwell A hardness （HRA） was higher than 92.5, the average grain size was less than 460 nm, when carbon content in nanocrystalline composite powder was 5.54wt% and the ball-milled time was 48 hours, ultrafine WC-10Co cemented carbide with excellent properties and homogeneous microstructure was obtained.展开更多
2k factorial design is employed to find the mathematical relation between the carbon content and intercritical annealing temperature （IAT） in order to predict the responses namely martensite volume fraction （MVF）,...2k factorial design is employed to find the mathematical relation between the carbon content and intercritical annealing temperature （IAT） in order to predict the responses namely martensite volume fraction （MVF）, microhardness （H）, yield strength （YS）, ultimate tensile strength （UTS）, total elongation （TEL）, yield ratio （YR） and Charpy impact energy （CIE） in dual phase （DP） steels. Steels containing different carbon contents （0.085% C and 0.380% C） had been chosen for this purpose. The main advantages of factorial design are its easy implementation and the effective computation compared with the other optimization techniques, which were employed for predicting mentioned responses in the literature. To verify the proposed approach based on factorial design, experiments for verification were performed. The results of the verification experiments and the mathematical models are in accordance with each other and the literature.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52174297).
文摘The endpoint carbon content in the converter is critical for the quality of steel products,and accurately predicting this parameter is an effective way to reduce alloy consumption and improve smelting efficiency.However,most scholars currently focus on modifying methods to enhance model accuracy,while overlooking the extent to which input parameters influence accuracy.To address this issue,in this study,a prediction model for the endpoint carbon content in the converter was developed using factor analysis(FA)and support vector machine(SVM)optimized by improved particle swarm optimization(IPSO).Analysis of the factors influencing the endpoint carbon content during the converter smelting process led to the identification of 21 input parameters.Subsequently,FA was used to reduce the dimensionality of the data and applied to the prediction model.The results demonstrate that the performance of the FA-IPSO-SVM model surpasses several existing methods,such as twin support vector regression and support vector machine.The model achieves hit rates of 89.59%,96.21%,and 98.74%within error ranges of±0.01%,±0.015%,and±0.02%,respectively.Finally,based on the prediction results obtained by sequentially removing input parameters,the parameters were classified into high influence(5%-7%),medium influence(2%-5%),and low influence(0-2%)categories according to their varying degrees of impact on prediction accuracy.This classi-fication provides a reference for selecting input parameters in future prediction models for endpoint carbon content.
基金financially supported by the National Natural Science Foundation of China(Nos.U2141207,52171111,and 52001083)the Youth Talent Project of China National Nuclear Corporation(No.CNNC2021Y-TEPHEU01)+3 种基金the China Postdoctoral Science Foundation(No.2020M681077)the Natural Science Foundation of Heilongjiang,China(No.LH2019E030)the Heilongjiang Postdoctoral Science Foundation,China(No.LBH-Z19125)he Heilongjiang Touyan Innovation Team Program,China,and the Natural Science Foundation of Heilongjiang(No.LH2020E060)。
文摘Carbon can change the phase components of low-density steels and influence the mechanical properties.In this study,a new method to control the carbon content and avoid the formation ofδ-ferrite by decarburization treatment was proposed.The microstructural changes and mechanical characteristics with carbon content induced by decarburization were systematically examined.Crussard-Jaoul(C-J)analysis was employed to examine the work hardening characteristics during the tensile test.During decarburization by heat treatments,the carbon content within the austenite phase decreased,while Mn and Al were almost unchanged;this made the steel with full austenite transform into the austenite and ferrite dual phase.Meanwhile,(Ti,V)C carbides existed in both matrix phase and the mole fraction almost the same.In addition,the formation of other carbides restrained.Carbon loss induced a decrease in strength due to the weakening of the carbon solid solution.For the steel with the single austinite,the deformation mode of austenite was the dislocation planar glide,resulting in the formation of microbands.For the dual-phase steel,the deformation occurred by the dislocation planar glide of austenite first,with the increase in strain,the cross slip of ferrite took place,forming dislocation cells in ferrite.At the late stage of deformation,the work hardening of austinite increased rapidly,while that of ferrite increased slightly.
基金financially supported by the General Research Institute for Nonferrous Metals Youth Science Foundation(No.52147)。
文摘The effects of cryogenic treatment(CT)and tempering-cryogenic treatment(TCT)on the microstructure and properties of coarse-grained WC-10Co cemented carbides with different carbon contents were researched.The binder phase,WC mean grain sizes,W solubility in the binder,relative magnetic s aturation,densities,hardness,wear resistance and second phase precipitation of cemented carbides with different heat treatments were discussed.The results show that there are significant changes of microstructure and properties in the samples with CT and TCT,especially due to the precipitation of metastable nanoparticles W_(x)Co_(y)C_(z) in the binder during the heat treatments of CT and TCT.With the simultaneous combination of microstructure and nanoparticle-reinforced binder,a dramatically improved combination of hardness and wear resistance of the samples after TCT has been achieved.
基金funded by the Shanghai Academic/Technology Research Leader(Project No.21XD1432000).
文摘The coating layers of Tri-structural Isotropic Particles(TRISO)serve to protect the kernel and act as barriers to fission products.Sintering aids in the silicon carbide matrix variably react with TRISO coating layers,leading to the destruction of the coating layers.Investigating how carbon content affects element diffusion in silicon carbide-based TRISO composite fuel is of great significance for predicting reactor safety.In this study,silicon carbide-based TRISO composite fuels with different carbon contents were prepared by adding varying amounts of phenolic resin to the silicon carbide matrix.X-ray Diffraction(XRD)and Scanning Electron Microscopy(SEM)were employed to characterize the phase composition,morphology,and microstructure of the composite fuels.The elemental content in each coating layer of TRISO was quantified using Energy-Dispersive X-ray Spectroscopy(EDS).The results demonstrated that the addition of phenolic resin promoted the uniform distribution of sintering aids in the silicon carbide matrix.The atomic percentage(at.%)of aluminum(Al)in the pyrolytic carbon layer of the TRISO particles reached its lowest value of 0.55%when the phenolic resin addition was 1%.This is because the addition of phenolic resin caused the Al and silicon(Si)in the matrix to preferentially react with the carbon in the phenolic resin to form a metastable liquid phase,rather than preferentially consuming the pyrolytic carbon in the outer coating layer of the TRISO particles.The findings suggest that carbon addition through phenolic resin incorporation can effectively mitigate the deleterious reactions between the TRISO coating layers and sintering aids,thereby enhancing the durability and safety of silicon carbide-based TRISO composite fuels.
基金Project supported by the Key Research Program of Guangdong Province (No. 2002C20703)the Key Research Program of the Forestry Administration of Guangdong Province (No. 2002-12).
文摘Global warming has become an increasing concern, and using soil as a carbon sink to sequester carbon dioxide has attracted much attention in recent years. In this study, soil organic carbon (SOC) content and organic carbon density were estimated based on a soil survey of a small landscape in Dongguan, South China, with spatial heterogeneity of SOC distribution and the impacts of land-use patterns on soil organic carbon content assessed. Field sampling was carried out based on a 150 m×150 m grid system overlaid on the topographic map of the study area and samples were collected in three 20-cm layers to a depth of 60 cm. Spatial variability in the distribution of SOC was assessed using the Kruskal-Wallis test. Results showed that SOC in the topsoil layer (0-20 cm) was not much higher or even lower in some sites than the underlying layers, and except for the two sites covered with natural woodland, it did not exhibit a pronounced vertical gradient. The difference in both horizontal and vertical distribution of SOC was not statistically significant. However, in the topsoil layer among land-use/land-cover patterns, significant differences (P≤0.05) in SOC distribution existed, indicating that management practices had great impact on SOC content. SOC storage in the study area to a depth of 20, 40, and 60 cm was estimated as 2.13×106 kg, 3.46×106 kg, and 4.61×106 kg, respectively.
基金supported by National Natural Science Foundation of China(No.51276100)the National Basic Research Program of China(973 Program)(No.2013CB228501)the financial funding from the U.S.Department of Energy,Office of Basic Energy Sciences,Chemical Science Division at Lawrence Berkeley National Laboratory(No.2013CB228501)
文摘The carbon content of bituminous coal samples was analyzed by laser-induced breakdown spectroscopy. The 266 nm laser radiation was utilized for laser ablation and plasma generation in air. The partial least square method and the dominant factor bused PLS method were used to improve the measurement accuracy of the carbon content of coal. The results showed that the PLS model could achieve good measurement accuracy, and the dominant factor based PLS model could further improve the measurement accuracy. The coefficient of determination and the root-mean-square error of prediction of the PLS model were 0.97 and 2.19%, respectively; and those values for the dominant factor based PLS model were 0.99 and 1.51%, respectively. The results demonstrated that the 266 nm wavelength could accurately measure the carbon content of bituminous coal.
基金Project(51274107)supported by the National Natural Science Foundation of ChinaProject(2015FB127)supported by the Yunnan Natural Science Foundation,ChinaProject(2016P20151130003)supported by Analysis Foundation of Kunming University of Science and Technology,China
文摘Pure WC-6%Co nanosized composite powders were synthesized via a low-temperature method.The effects of carbon source on microstructure characteristic of composite powders were investigated,and the effects of heat-treatment parameter on carbon content of composite powders were also discussed.The results of SEM and XRD revealed that the carbon decomposing from glucose was more active than carbon black.Therefore,WC-Co nanosized composite powders could be synthesized at 900°C for 1 h under a hydrogen atmosphere.The individual WC grains were bonded together into a long strip under the action of cobalt.The results of carbon analysis revealed that the total carbon content decreased with the increase of the temperature in the range of 800-1000°C.Moreover,the total carbon content and the compounded carbon increased with the increase of the flow rate of H2 in the range of 1.1-1.9 m3/h.
文摘The effects of finishing rolling temperature and coiling temperature on retained austen-ite were studied for hot-rolled transformation induced plasticity (TRIP) steels with different carbon content. The experimental results showed that an appropriate volume fraction of retained austenite from 6% to 11% could be obtained according to the different carbon content less than 0.20% by controlled finishing rolling and coiling for the hot-rolled TRIP steels. It can be concluded that carbon content has a significant effect on the fraction of retained austenite and coiling processing plays stronger role on retaining austenite than fishing rolling processing.
文摘The thermal conductivity or diffusivity of pearlitic grey irons with various carbon contents is investigated by the laser flash method. The materials are cast in controlled thermal environments and produced in three dissimilar cooling rates. The cooling rate together with the carbon content largely influence the thermal conductivity of grey iron. Linear relationships exist between the thermal conductivity and the carbon content,the carbon equivalent and the fraction of former primary solidified austenite transformed into pearlite. The work shows that optimal thermal transport properties are obtained at medium cooling rates. Equations describing the thermal conductivity of pearlite,solidified as pre-eutectic austenite,and the eutectic of grey iron are derived. The thermal conductivity of pearlitic grey iron is modeled at both room temperature and elevated temperature with good accuracy.
基金Project(51604131)supported by the National Natural Science Foundation of ChinaProject(2017FB084)supported by the Yunnan Province Applied Basic Research,China+1 种基金Project(KKSY201563041)supported by the Talent&Training Program of Yunnan Province,ChinaProjects(2017T20090159,2018T20150055)supported by the Testing and Analyzing Funds of Kunming University of Science and Technology,China
文摘Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)with a relative high concentration using different kinds of ZVI powders(mainly carbon differences)including reduced Fe,grey cast iron,pig iron,nodular pig iron was carried out.Parameters such as ZVI dosage,type and size affecting on Cr(VI)reduction were firstly examined and grey cast iron was selected as a preferable reducing material,followed by pig iron.Additionally,it was found that the parameters had significant influences on experimental kinetics.Then,morphology and composition of the sample before and after reaction were characterized by SEM,EPMA and XPS analyses to disclose carbon effect on the reducibility.In order to further interpret reaction mechanism,different reaction models were constructed.It was revealed that not only the carbon content could affect the Cr(VI)reduction,but also the carbon structure had an important effect on its reduction.
文摘The reaction activity of S Zorb sorbents with different sulfur contents was investigated, and the structure and composition of carbon-containing sorbents were characterized by XRD, FT-IR and TG-MS in order to delve into the kind and morphology of carbon on the sorbent. Test results have revealed that coke could be deposited on the S Zorb sorbent during the operating process, and the coke content was an important factor influencing the reaction performance of the S Zorb sorbent. Retention of a definite amount of coke on the sorbent while securing the desulfurization activity of the S Zorb sorbent would be conducive to the reduction of octane loss of reaction product.
基金supported by the National Key Research and Development Program of China (2016YFD0300602)China Agricultural Research System (CARS-04-PS19)Chengdu Science and Technology Project (2020-YF09-00033-SN)。
文摘Assessing canopy nitrogen content(CNC) and canopy carbon content(CCC) of maize by hyperspectral remote sensing data permits estimating cropland productivity, protecting farmland ecology, and investigating the nitrogen and carbon cycles in the atmosphere. This study aimed to assess maize CNC and CCC using canopy hyperspectral information and uninformative variable elimination(UVE). Vegetation indices(VIs) and wavelet functions were adopted for estimating CNC and CCC under varying water and nitrogen regimes. Linear, nonlinear, and partial least squares(PLS) regression models were fitted to VIs and wavelet functions to estimate CNC and CCC, and were evaluated for their prediction accuracy.UVE was used to eliminate uninformative variables, improve the prediction accuracy of the models, and simplify the PLS regression models(UVE-PLS). For estimating CNC and CCC, the normalized difference vegetation index(NDVI, based on red edge and NIR wavebands) yielded the highest correlation coefficients(r > 0.88). PLS regression models showed the lowest root mean square error(RMSE) among all models. However, PLS regression models required nine VIs and four wavelet functions, increasing their complexity. UVE was used to retain valid spectral parameters and optimize the PLS regression models.UVE-PLS regression models improved validation accuracy and resulted in more accurate CNC and CCC than the PLS regression models. Thus, canopy spectral reflectance integrated with UVE-PLS can accurately reflect maize leaf nitrogen and carbon status.
文摘The in situ Al 2O 3p TiC p/Al composite was fabricated by XD (exothermic dispersion) process in TiO 2 Al C system, and the effect of carbon content on the microstructure of the fabricated composite and the reactive temperature characteristics had been studied. The results show that carbon content affects the microstructure and reactive temperature of Al 2O 3p TiC p/Al composite greatly. The quantity of TiC phases in the fabricated composites increases, while the Al 3Ti phases reduces with increasing carbon content. And when C/TiO 2 molecular ratio is equal to one, the Al 3Ti phase nearly disappears. High temperature metallurgical field caused by strong exothermic reaction influences the synthetic reaction greatly, and higher synthetic temperature was favorable to the synthesis of Al 2O 3p TiC p reinforce particles.
基金Item Sponsored by Industry-University Cooperation Major Program of Science and Technology Department of Fujian Province of China(2011H6012)Key Program of Science and Technology Department of Fujian Province of China(2011H0001)
文摘The influence of carbon content on the stacking fault energy （SFE） of Fe-20Mn-3Cu twinning-induced plasticity （TWIP） steel was investigated by means of X-ray diffraction peak-shift method and thermodynamic modeling. The experimental result indicated that the stacking fault probability decreases with increasing carbon addition, the SFE increases linearly when the carbon content in mass percent is between 0.23 M and 1.41%. The thermody namic calculation results showed that the SFE varied from 22.40 to 29.64 mJ ~ m 2 when the carbon content in mass percent changes from 0.23 % to 1.41%. The XRD analysis revealed that all steels were fully austenitic before and after deformation, which suggested that TWIP effect is the predominant mechanism during the tensile deformation process of Fe-20Mn-3Cu-XC steels.
文摘The micro structure and mechanical properties of new kind of hot-rolled high strength and high elongation steels with retained austenite were studied by discussing the influence of different carbon content. The research results indicate that carbon content has a significant effect on retaining austenite and consequently resulting in high elongation. Besides, new findings about relationship between carbon content and retained austenite as well as properties were discussed in the paper.
基金This project was funded by the Open Fund of the Key Laboratory of Exploration Technologies for Oil and Gas Resources,the Ministry of Education(No.K2021-03)National Natural Science Foundation of China(No.42106213)+2 种基金the Hainan Provincial Natural Science Foundation of China(No.421QN281)the China Postdoctoral Science Foundation(Nos.2021M690161 and 2021T140691)the Postdoctorate Funded Project in Hainan Province.
文摘The total organic carbon content usually determines the hydrocarbon generation potential of a formation.A higher total organic carbon content often corresponds to a greater possibility of generating large amounts of oil or gas.Hence,accurately calculating the total organic carbon content in a formation is very important.Present research is focused on precisely calculating the total organic carbon content based on machine learning.At present,many machine learning methods,including backpropagation neural networks,support vector regression,random forests,extreme learning machines,and deep learning,are employed to evaluate the total organic carbon content.However,the principles and perspectives of various machine learning algorithms are quite different.This paper reviews the application of various machine learning algorithms to deal with total organic carbon content evaluation problems.Of various machine learning algorithms used for TOC content predication,two algorithms,the backpropagation neural network and support vector regression are the most commonly used,and the backpropagation neural network is sometimes combined with many other algorithms to achieve better results.Additionally,combining multiple algorithms or using deep learning to increase the number of network layers can further improve the total organic carbon content prediction.The prediction by backpropagation neural network may be better than that by support vector regression;nevertheless,using any type of machine learning algorithm improves the total organic carbon content prediction in a given research block.According to some published literature,the determination coefficient(R^(2))can be increased by up to 0.46 after using machine learning.Deep learning algorithms may be the next breakthrough direction that can significantly improve the prediction of the total organic carbon content.Evaluating the total organic carbon content based on machine learning is of great significance.
基金supported by SGC project5 entitled"Mobile Biochar Production for Methane Emission Reduction and Soil Amendment".Grant Agreement#CCR20014supported in part by NSF CBET#1856112supported in part by an F3 R&D GSR Award (Farms Food Future Innovation Initiative (or F3),as funded by US Dept.of Commerce,Economic Development Administration Build Back Better Regional Challenge).
文摘Agricultural and forestry biomass can be converted to biochar through pyrolysis gasification,making it a significant carbon source for soil.Applying biochar to soil is a carbon-negative process that helps combat climate change,sustain soil biodiversity,and regulate water cycling.However,quantifying soil carbon content conventionally is time-consuming,labor-intensive,imprecise,and expensive,making it difficult to accurately measure in-field soil carbon’s effect on storage water and nutrients.To address this challenge,this paper for the first time,reports on extensive lab tests demonstrating non-intrusive methods for sensing soil carbon and related smart biochar applications,such as differentiating between biochar types from various biomass feedstock species,monitoring soil moisture,and biochar water retention capacity using portable microwave and millimeter wave sensors,and machine learning.These methods can be scaled up by deploying the sensor in-field on a mobility platform,either ground or aerial.The paper provides details on the materials,methods,machine learning workflow,and results of our investigations.The significance of this work lays the foundation for assessing carbon-negative technology applications,such as soil carbon content accounting.We validated our quantification method using supervised machine learning algorithms by collecting real soil mixed with known biochar contents in the field.The results show that the millimeter wave sensor achieves high sensing accuracy(up to 100%)with proper classifiers selected and outperforms the microwave sensor by approximately 10%–15%accuracy in sensing soil carbon content.
基金the financial support from the National Natural Science Foundation of China(Nos. 51171025 and 51271023)Fundamental Research Funds for the Central Universities(No.FRF-TP-12-144A)the National Network of Field Observation & Scientific Research on Material Environmental Corrosion
文摘New steels with different carbon contents were self-developed by thermo-mechanical controlled processing. The effects of the carbon content and the microstructure on the corrosion properties of new steels were investigated by immersion test and SEM. The results indicated that the ferrite phase （both the proeutectoid and eutectoid ferrite） dissolved preferentially. Cementite reserved and accumulated on the surface. As carbon content increased, the content of ferrite decreased and cathode/anode area ratio increased. Therefore, the corrosion rate of new steels increased from 0.30 to 0.90 mm/years when the carbon content rose from 0.05 to 0.13 wt%. The corrosion process of new steels was studied using electrochemical impedance spectroscopy experiments during 72 h. It indicated that the impedance modulus IZlo.ol nz of the new steels reduces with the increase of the immersion time. While the corrosion process of the new steel with 0.11 wt% C developed faster than that with 0.07 wt% C, although their IZlo.ol nz was similar at the initial stage.
基金the National Natural Science Foundation of China (No.50502026)the Youth Science Plan for Light of the Morning Sun of Wuhan City(No.200750731270)Key Project for the Science & Technology Research Department,Chinese Ministry of Education (No.105123)
文摘WC-10Co nanocrystalline composite powders prepared by spray pyrogenation-continuous reduction and carburization technology were consolidated by vacuum sintering plus hot isostatic pressing （HIP）. Influences of carbon content on properties and microstructure of ultrafine WC-10Co cemented carbide were investigated. The results show that the relative density of the ultrafine WC-10Co cemented carbides can reach 99.72%, and the transverse rupture strength （TRS） was higher than 3 890 MPa, Rockwell A hardness （HRA） was higher than 92.5, the average grain size was less than 460 nm, when carbon content in nanocrystalline composite powder was 5.54wt% and the ball-milled time was 48 hours, ultrafine WC-10Co cemented carbide with excellent properties and homogeneous microstructure was obtained.
文摘2k factorial design is employed to find the mathematical relation between the carbon content and intercritical annealing temperature （IAT） in order to predict the responses namely martensite volume fraction （MVF）, microhardness （H）, yield strength （YS）, ultimate tensile strength （UTS）, total elongation （TEL）, yield ratio （YR） and Charpy impact energy （CIE） in dual phase （DP） steels. Steels containing different carbon contents （0.085% C and 0.380% C） had been chosen for this purpose. The main advantages of factorial design are its easy implementation and the effective computation compared with the other optimization techniques, which were employed for predicting mentioned responses in the literature. To verify the proposed approach based on factorial design, experiments for verification were performed. The results of the verification experiments and the mathematical models are in accordance with each other and the literature.
