Ni-based anodes of SOFCs are susceptible to coking, which greatly limits practical application of direct methane-based fuels. An indirect internal reformer is an effective way to convert methane-based fuels into synga...Ni-based anodes of SOFCs are susceptible to coking, which greatly limits practical application of direct methane-based fuels. An indirect internal reformer is an effective way to convert methane-based fuels into syngas before they reach anode. In this work, catalytic activity of a redox-stable perovskite La0.7Sr0.3Cr0.8Fe0.2O3-δ(LSCrFO) for methane conversion was evaluated. The catalyst was fabricated as an anodic protective layer to improve coking resistance of a Ni cermet anode. Using wet CH4 as a fuel, the LSCrFO-modified cell showed excellent power output and good coking resistance with peak power density of 1.59 W cm-2 at 800℃. The cell demonstrated good durability lasting for at least 100 h. While the bare cell without the protective layer showed poor durability with the cell voltage fast dropped from 0.75 V to 0.4 V within 30 min. Under wet coal bed methane (CBM) operation, obvious performance degradation within 35 h (1.7 mV h^-1) was observed due to the influence of heavy carbon compounds in CBM. The pre-and post-mortem microstructures and carbon analysis of the anode surface and catalyst surface were further conducted.展开更多
In conventional isochronous mass spectrometry(IMS)performed on a storage ring,the precision of mass measurements for short-lived nuclei depends on the accurate determination of the revolution times(T)of stored ions.Ho...In conventional isochronous mass spectrometry(IMS)performed on a storage ring,the precision of mass measurements for short-lived nuclei depends on the accurate determination of the revolution times(T)of stored ions.However,the resolution of T inevitably deteriorates due to the magnetic rigidity spread of the ions,limiting the mass-resolving power.In this study,we used the betatron tunes Q(the number of betatron oscillations per revolution)of the ions and established a correlation between T and Q.From this correlation,T was transformed to correspond to a fixed Q with higher resolution.Using these transformed T values,the masses of ^(63)Ge,^(65)As,^(67)Se,and ^(71)Kr agreed well with the mass values measured using the newly developed IMS(Bρ-IMS).We also studied the systematics of Coulomb displacement energies(CDEs)and found that anomalous staggering in CDEs was eliminated using new mass values.This method of T transformation is highly effective for conventional IMS equipped with a single time-of-flight detector.展开更多
For positive integers k and r,a(k,r)-coloring of graph G is a proper vertex k-coloring of G such that the neighbors of any vertex v∈V(G)receive at least min{d_(G)(v),r}different colors.The r-hued chromatic number of ...For positive integers k and r,a(k,r)-coloring of graph G is a proper vertex k-coloring of G such that the neighbors of any vertex v∈V(G)receive at least min{d_(G)(v),r}different colors.The r-hued chromatic number of G,denoted χ_(r)(G),is the smallest integer k such that G admits a(k,r)-coloring.Let Q_(n) be the n-dimensional hypercube.For any integers n and r with n≥2 and 2≤r≤5,we investigated the behavior of χ_(r)(Q_(n)),and determined the exact value of χ_(2)(Q_(n))and χ_(3)(Q_(n))for all positive integers n.展开更多
Background:In this study,we explored the effects of different processing methods on the quality of Polygonatum cyrtonema Hua(PC),and the role of Huangjiu in the processing procedure.Methods:The sensory characteristics...Background:In this study,we explored the effects of different processing methods on the quality of Polygonatum cyrtonema Hua(PC),and the role of Huangjiu in the processing procedure.Methods:The sensory characteristics of the crude product,steamed product,and wine-processed product of PC were described.The colorimeter was used to analyze the chromatic values of three different processed products on PC.At the same time,the contents of the water extract and alcohol extract were measured separately.The content of three different processing Polygonatum Polysaccharide(PCP)was determined using 0.2%anthrone-sulfuric acid.The correlation difference between the chromatic values and chemical composition of different PC products was analyzed using various analytical methods.Results:The surface colors gradually deepened,the sweetness increased,the viscosity strengthened,and the tongue-numbing sensation disappeared after PC processing.The contents of extract and L^(*) gradually decreased from the crude to the steamed to the wine-processed product,consistent with the pattern of surface color alteration.While,E^(*)ab gradually increased.The content of PCP was crude product>wine-processed product>steamed product.The results of multivariate statistical analysis showed that the samples processed for crude,steamed,and wine-processed product were clustered into three classes.The correlation analysis showed that L^(*)and E^(*)ab were highly significant positively correlated with the content of PCP,and a*was significantly negatively correlated with the content of PCP.Conclusion:The results showed that the wine-processed product had the best quality.The internal quality of the PC was correlated with its characteristics and chromatic value.In this study,we investigated the internal and external quality of three different products of PC in order to provide a reference for further research on the impact of different processing methods on PC quality,the standardization of PC processing,and the role of Huangjiu in the processing of PC.展开更多
With the intensification of market competition in the aluminum alloy strip processing industry,it is dif-ficult to control the mass production of the same specifications,which is bound to affect the hot rolling produc...With the intensification of market competition in the aluminum alloy strip processing industry,it is dif-ficult to control the mass production of the same specifications,which is bound to affect the hot rolling production.This paper studied the effect of the hot rolling order of aluminum alloy on the surface quality of strip,such as roll printing,color difference,anodic oxidation,etc.,reasonable discharge sequence and corresponding optimization measures were formulated.展开更多
An edge coloring of hypergraph H is a function such that holds for any pair of intersecting edges . The minimum number of colors in edge colorings of H is called the chromatic index of H and is ...An edge coloring of hypergraph H is a function such that holds for any pair of intersecting edges . The minimum number of colors in edge colorings of H is called the chromatic index of H and is denoted by . Erdös, Faber and Lovász proposed a famous conjecture that holds for any loopless linear hypergraph H with n vertices. In this paper, we show that is true for gap-restricted hypergraphs. Our result extends a result of Alesandroni in 2021.展开更多
In order to clean production of chromium compounds, it is a critical process to remove aluminates and utilize aluminum compounds from artificial chromate alkali solutions. The effects of Na2 Cr O4 on the neutralizatio...In order to clean production of chromium compounds, it is a critical process to remove aluminates and utilize aluminum compounds from artificial chromate alkali solutions. The effects of Na2 Cr O4 on the neutralization curve, Al(OH)3 precipitation efficiency and induction period of bayerite were investigated. The results indicate that the neutralization curve of the artificial chromate alkali solutions shows three distinct regions and its induction period is longer than that of pure sodium aluminate solutions at the same aluminum concentration. And the decreased temperature and volume fraction of CO2 enhance the particle size of bayerite β-Al(OH)3. Bayerite composed of agglomerates of rods and cone frustums was obtained from alkali metal chromate solutions with 28.5% CO2(volume fraction) at temperatures ranging from 50 °C to 70 °C. Coarse bayerite with particle size(d50) from 24.2 μm to 29.3 μm extremely has few impurities, which is suitable for comprehensive utilization.展开更多
The oxidizing roasting process of carbon ferrochrome to prepare potassium chromate in the presence of potassium carbonate and air was investigated. The effects of reaction temperature, reaction time, mole ratio of pot...The oxidizing roasting process of carbon ferrochrome to prepare potassium chromate in the presence of potassium carbonate and air was investigated. The effects of reaction temperature, reaction time, mole ratio of potassium carbonate to carbon ferrochrome were studied, and thermodynamics and kinetics were also discussed. It was observed that the reaction temperature and reaction time had a significant influence on the roasting reaction of carbon ferrochrome. The reaction mechanism changed greatly as the temperature varied. A two-stage roasting process was favorable for the roasting reaction, and a chromium recovery rate of 97.06% was obtained through this two-stage roasting method. The chromium residue yielded from this method was only 1/3 of the product. Moreover, the component of Fe in the residue was as high as 55.04%. Therefore, it can be easily recovered to produce sponge iron, realizing complete detoxication and zero-emission of chromium residue.展开更多
For the clean and economical production of chromium compounds, it is crucial to remove aluminates from chromate alkali solutions and utilize aluminum-containing compounds. In this work, carbonization was used to remov...For the clean and economical production of chromium compounds, it is crucial to remove aluminates from chromate alkali solutions and utilize aluminum-containing compounds. In this work, carbonization was used to remove aluminates from a synthetic chromate leaching solution containing a high K2O/Al2O3 mole ratio. The influence of reaction temperature, carbonization time, flow rate of carbon dioxide, and seed ratio on the precipitation of Al was investigated. The optimal output was obtained under the following experimental conditions: a reaction temperature of 50 °C, a carbonization time of 100 min, a carbon dioxide flow rate of 0.1 L/min, and a seed ratio of 1.0. Gibbsite was obtained following carbonization. The structure and morphology of the gibbsite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and laser particle size analyzer. The particle size distribution and morphology of the gibbsite were significantly influenced by the experimental conditions. The gibbsite had a mean particle size (d50) of 16.72μm. The thermal decomposition of the gibbsite was analyzed by XRD and the decomposition path was determined. The obtained coarseα-Al2O3 precipitate, which contains 0.08% Cr2O3 and 0.10% K2O, was suitable for subsequent utilization.展开更多
An objectifying system for color inspections of traditional Chinese medicine (CITCM) is developed. The entire system includes two parts : The hardware and the software. The hardware is an image acquiring device und...An objectifying system for color inspections of traditional Chinese medicine (CITCM) is developed. The entire system includes two parts : The hardware and the software. The hardware is an image acquiring device under a standard lighting condition, and it mainly includes a xenon lamp with color temperature of 5 500 K as light source, an integrating sphere used for diffusing light and a high resolution CCD camera. The software is used for digital image processing, and the procedure is divided into three steps. Firstly the skin/non-skin classifi- cation is performed by utilizing the threshold in chrominance channels of the RGB color space. Secondly, the fa- cial features are localized by using the image segmentation and coordinates sorting. Finally, the facial special re- gion(SR) corresponding to five internal organs is achieved by utilizing masks designed to take advantage of mor- phology. Subsequently, the chromaticity is calculated. The system is tested by taking 83 samples of 30 young and 53 elderly people. The experiment shows that there is significant difference of all SRs between the young and the elderly, and the system has better performance for objectifying research of CITCM.展开更多
An integer distance graph is a graph G(Z, D) with the integer set Z as vertexset, in which an edge joining two vertices u and v if and only if | u - v | ∈ D, where D is a setof natural numbers. Using a related theore...An integer distance graph is a graph G(Z, D) with the integer set Z as vertexset, in which an edge joining two vertices u and v if and only if | u - v | ∈ D, where D is a setof natural numbers. Using a related theorem in combinatorics and some conclusions known to us in thecoloring of the distance graph, the chromatic number _X(G) is determined in this paper that is ofthe distance graph G(Z, D) for some finite distance sets D containing {2, 3} with D = 4 andcontaining {2, 3, 5} with | D | = 5 by the method in which the combination of a few periodiccolorings.展开更多
A new regression algorithm of an adaptive reduced relevance vector machine is proposed to estimate the illumination chromaticity of an image for the purpose of color constancy. Within the framework of sparse Bayesian ...A new regression algorithm of an adaptive reduced relevance vector machine is proposed to estimate the illumination chromaticity of an image for the purpose of color constancy. Within the framework of sparse Bayesian learning, the algorithm extends the relevance vector machine by combining global and local kernels adaptively in the form of multiple kernels, and the improved locality preserving projection (LLP) is then applied to reduce the column dimension of the multiple kernel input matrix to achieve less training time. To estimate the illumination chromaticity, the algorithm is trained by fuzzy central values of chromaticity histograms of a set of images and the corresponding illuminants. Experiments with real images indicate that the proposed algorithm performs better than the support vector machine and the relevance vector machine while requiring less training time than the relevance vector machine.展开更多
In this paper, using the properties of chromatic polynomial, we discuss the color-partition of the complement of lK 1∪(∪C u i),and characterize the graph with the same color-partition as the class graph under u...In this paper, using the properties of chromatic polynomial, we discuss the color-partition of the complement of lK 1∪(∪C u i),and characterize the graph with the same color-partition as the class graph under u i≠4k+2.展开更多
A graph is called star extremal if its fractional chromatic number is equal to its circular chromatic number. We first give a necessary and sufficient condition for a graph G to have circular chromatic number V(G)/α(...A graph is called star extremal if its fractional chromatic number is equal to its circular chromatic number. We first give a necessary and sufficient condition for a graph G to have circular chromatic number V(G)/α(G) (where V(G) is the vertex number of G and α(G) is its independence number). From this result, we get a necessary and sufficient condition for a vertex-transitive graph to be star extremal as well as a necessary and sufficient condition for a circulant graph to be star extremal. Using these conditions, we obtain several classes of star extremal graphs.展开更多
Chromatic adaptation of human eyes to complex field is investigated using binocular asymmetric matching method. The results show that the leve of chromatic adapta- tion mainly depends on the average color of adapting ...Chromatic adaptation of human eyes to complex field is investigated using binocular asymmetric matching method. The results show that the leve of chromatic adapta- tion mainly depends on the average color of adapting field, whereas no obvious change oc- curs when the number of hues and their color differences vary in a complex field. The shifts of perceived color evoked by chromatic adaptation in CIE 1976 L U V color space are approximately proportional to the average color difference between the adapting field and reference field.展开更多
Effects of varieties on the content of tea pigment, L*, a* and b* value of chromatic aberration of black tea infusion was studied. The correlation relationship between content of TF, TR, TB and L*, a*, b* value ...Effects of varieties on the content of tea pigment, L*, a* and b* value of chromatic aberration of black tea infusion was studied. The correlation relationship between content of TF, TR, TB and L*, a*, b* value was extremely significant at P<0.05. Fresh tea leaves with plucking standard of 1 bud and 2 leaves could man-ufacture black tea with higher content of tea pigment, higher a* and b* value but lower L* value, than those of plucking standard of 1 bud and 3 leaves. But the discrepancy of certain parameter of the two plucking standards changed with vari-eties. Varieties’ quality potential could be concealed by improper plucking standards. Six varieties were divided into four groups on the basis of gross tea polyphenols in fresh tea leaves (GTP), consumption of tea polyphenols to gross tea polyphenols ratio (CTP/GTP) and gross tea pigment to consumption of tea polyphenols ratio (GP/CTP). Hybrid performed the very suitability of black tea manufacturing. To en-sure high quality of made black tea, suitable variety should be chosen and reason-able plucking standard also should be taken into consideration.展开更多
An oxidizing roasting process of carbon ferrochrome to prepare sodium chromate in the presence of sodium carbonate and air was investigated. The effects of reaction temperature, reaction time, mole ratio of sodium car...An oxidizing roasting process of carbon ferrochrome to prepare sodium chromate in the presence of sodium carbonate and air was investigated. The effects of reaction temperature, reaction time, mole ratio of sodium carbonate to carbon ferrochrome were studied, and thermodynamics and kinetics of the reaction were also discussed. It was observed that there was a sudden increase in reaction rate when the temperature rose to a certain value, and the sample with a smaller grain size could start the sudden increase at a lower temperature. The chromium recovery rate increased with the increase of mole ratio of sodium carbonate to carbon ferrochrome, and it reached up to 99.34% when mole ratio of sodium carbonate to carbon ferrochrome increased to 1.2:1. The chromium residue yielded from this method was only about 1/3 of the product. Moreover, the content of Fe in the residue was as high as 60.41%. Therefore, it can be easily recovered to produce sponge iron, realizing complete detoxication and zero-emission of chromium residue.展开更多
In this paper, using the properties of chromatic polynomial, we discuss the color-partition of the complement of lK 1∪(∪C u i),and characterize the graph with the same color-partition as the class graph under u...In this paper, using the properties of chromatic polynomial, we discuss the color-partition of the complement of lK 1∪(∪C u i),and characterize the graph with the same color-partition as the class graph under u i≠4k+2.展开更多
基金supported by the Coal Seam Gas Joint Foundation of Shanxi(2015012016)Shanxi Province Science Foundation(2016011025)+2 种基金Shanxi Scholarship Council of China(2016-010)Shanxi “1331 Project” Key Innovative Research Team(“1331KIRT”)the Open Funding from State Key Laboratory of Materialoriented Chemical Engineering(No.KL16-03)
文摘Ni-based anodes of SOFCs are susceptible to coking, which greatly limits practical application of direct methane-based fuels. An indirect internal reformer is an effective way to convert methane-based fuels into syngas before they reach anode. In this work, catalytic activity of a redox-stable perovskite La0.7Sr0.3Cr0.8Fe0.2O3-δ(LSCrFO) for methane conversion was evaluated. The catalyst was fabricated as an anodic protective layer to improve coking resistance of a Ni cermet anode. Using wet CH4 as a fuel, the LSCrFO-modified cell showed excellent power output and good coking resistance with peak power density of 1.59 W cm-2 at 800℃. The cell demonstrated good durability lasting for at least 100 h. While the bare cell without the protective layer showed poor durability with the cell voltage fast dropped from 0.75 V to 0.4 V within 30 min. Under wet coal bed methane (CBM) operation, obvious performance degradation within 35 h (1.7 mV h^-1) was observed due to the influence of heavy carbon compounds in CBM. The pre-and post-mortem microstructures and carbon analysis of the anode surface and catalyst surface were further conducted.
基金supported in part by the National Key R&D Program of China (No. 2023YFA1606401)CAS Project for Young Scientists in Basic Research (No. YSBR-002)+3 种基金Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB34000000)the NSFC (Nos. 12305126, 12135017, 12121005)the support from the Youth Innovation Promotion Association of the Chinese Academy of Sciences (No. 2021419)the support from the Yong Scholar of Regional Development,CAS (No.[2023]15)
文摘In conventional isochronous mass spectrometry(IMS)performed on a storage ring,the precision of mass measurements for short-lived nuclei depends on the accurate determination of the revolution times(T)of stored ions.However,the resolution of T inevitably deteriorates due to the magnetic rigidity spread of the ions,limiting the mass-resolving power.In this study,we used the betatron tunes Q(the number of betatron oscillations per revolution)of the ions and established a correlation between T and Q.From this correlation,T was transformed to correspond to a fixed Q with higher resolution.Using these transformed T values,the masses of ^(63)Ge,^(65)As,^(67)Se,and ^(71)Kr agreed well with the mass values measured using the newly developed IMS(Bρ-IMS).We also studied the systematics of Coulomb displacement energies(CDEs)and found that anomalous staggering in CDEs was eliminated using new mass values.This method of T transformation is highly effective for conventional IMS equipped with a single time-of-flight detector.
基金supported by Natural Science Foundation of Xinjiang Uygur Autonomous Region of China“Spanning connectivity and supereulerian properties of graphs”(2022D01C410).
文摘For positive integers k and r,a(k,r)-coloring of graph G is a proper vertex k-coloring of G such that the neighbors of any vertex v∈V(G)receive at least min{d_(G)(v),r}different colors.The r-hued chromatic number of G,denoted χ_(r)(G),is the smallest integer k such that G admits a(k,r)-coloring.Let Q_(n) be the n-dimensional hypercube.For any integers n and r with n≥2 and 2≤r≤5,we investigated the behavior of χ_(r)(Q_(n)),and determined the exact value of χ_(2)(Q_(n))and χ_(3)(Q_(n))for all positive integers n.
基金sponsored by National Key Research and Development Program of China(2023YFC3504200)High Level Key Discipline Construction of Traditional Chinese Medicine(zyyzdxk-2023272).
文摘Background:In this study,we explored the effects of different processing methods on the quality of Polygonatum cyrtonema Hua(PC),and the role of Huangjiu in the processing procedure.Methods:The sensory characteristics of the crude product,steamed product,and wine-processed product of PC were described.The colorimeter was used to analyze the chromatic values of three different processed products on PC.At the same time,the contents of the water extract and alcohol extract were measured separately.The content of three different processing Polygonatum Polysaccharide(PCP)was determined using 0.2%anthrone-sulfuric acid.The correlation difference between the chromatic values and chemical composition of different PC products was analyzed using various analytical methods.Results:The surface colors gradually deepened,the sweetness increased,the viscosity strengthened,and the tongue-numbing sensation disappeared after PC processing.The contents of extract and L^(*) gradually decreased from the crude to the steamed to the wine-processed product,consistent with the pattern of surface color alteration.While,E^(*)ab gradually increased.The content of PCP was crude product>wine-processed product>steamed product.The results of multivariate statistical analysis showed that the samples processed for crude,steamed,and wine-processed product were clustered into three classes.The correlation analysis showed that L^(*)and E^(*)ab were highly significant positively correlated with the content of PCP,and a*was significantly negatively correlated with the content of PCP.Conclusion:The results showed that the wine-processed product had the best quality.The internal quality of the PC was correlated with its characteristics and chromatic value.In this study,we investigated the internal and external quality of three different products of PC in order to provide a reference for further research on the impact of different processing methods on PC quality,the standardization of PC processing,and the role of Huangjiu in the processing of PC.
文摘With the intensification of market competition in the aluminum alloy strip processing industry,it is dif-ficult to control the mass production of the same specifications,which is bound to affect the hot rolling production.This paper studied the effect of the hot rolling order of aluminum alloy on the surface quality of strip,such as roll printing,color difference,anodic oxidation,etc.,reasonable discharge sequence and corresponding optimization measures were formulated.
文摘An edge coloring of hypergraph H is a function such that holds for any pair of intersecting edges . The minimum number of colors in edge colorings of H is called the chromatic index of H and is denoted by . Erdös, Faber and Lovász proposed a famous conjecture that holds for any loopless linear hypergraph H with n vertices. In this paper, we show that is true for gap-restricted hypergraphs. Our result extends a result of Alesandroni in 2021.
基金Project(51125018)supported by the National Science Found for Distinguished Young Scholars of ChinaProject(2011BAC06B07)supported by the National Key Technologies R&D Program of China+2 种基金Project(2011AA060704)supported by the National Hi-tech Research and Development Program of ChinaProjects(51204153,21106167)supported by the National Natural Science Foundation of ChinaProjects(2012M510552,2013T60175)supported by Financial Grant from the China Postdoctoral Science Foundation
文摘In order to clean production of chromium compounds, it is a critical process to remove aluminates and utilize aluminum compounds from artificial chromate alkali solutions. The effects of Na2 Cr O4 on the neutralization curve, Al(OH)3 precipitation efficiency and induction period of bayerite were investigated. The results indicate that the neutralization curve of the artificial chromate alkali solutions shows three distinct regions and its induction period is longer than that of pure sodium aluminate solutions at the same aluminum concentration. And the decreased temperature and volume fraction of CO2 enhance the particle size of bayerite β-Al(OH)3. Bayerite composed of agglomerates of rods and cone frustums was obtained from alkali metal chromate solutions with 28.5% CO2(volume fraction) at temperatures ranging from 50 °C to 70 °C. Coarse bayerite with particle size(d50) from 24.2 μm to 29.3 μm extremely has few impurities, which is suitable for comprehensive utilization.
基金Project(2009GK2003)supported by the Natural Science Foundation of Hunan Province,China
文摘The oxidizing roasting process of carbon ferrochrome to prepare potassium chromate in the presence of potassium carbonate and air was investigated. The effects of reaction temperature, reaction time, mole ratio of potassium carbonate to carbon ferrochrome were studied, and thermodynamics and kinetics were also discussed. It was observed that the reaction temperature and reaction time had a significant influence on the roasting reaction of carbon ferrochrome. The reaction mechanism changed greatly as the temperature varied. A two-stage roasting process was favorable for the roasting reaction, and a chromium recovery rate of 97.06% was obtained through this two-stage roasting method. The chromium residue yielded from this method was only 1/3 of the product. Moreover, the component of Fe in the residue was as high as 55.04%. Therefore, it can be easily recovered to produce sponge iron, realizing complete detoxication and zero-emission of chromium residue.
基金Project(51125018)supported by the National Science Foundation for Distinguished Young Scholars of ChinaProject(2011AA060704)supported by the National High-tech Research and Development Program of ChinaProjects(51204153,21406246)supported by the National Natural Science Foundation of China
文摘For the clean and economical production of chromium compounds, it is crucial to remove aluminates from chromate alkali solutions and utilize aluminum-containing compounds. In this work, carbonization was used to remove aluminates from a synthetic chromate leaching solution containing a high K2O/Al2O3 mole ratio. The influence of reaction temperature, carbonization time, flow rate of carbon dioxide, and seed ratio on the precipitation of Al was investigated. The optimal output was obtained under the following experimental conditions: a reaction temperature of 50 °C, a carbonization time of 100 min, a carbon dioxide flow rate of 0.1 L/min, and a seed ratio of 1.0. Gibbsite was obtained following carbonization. The structure and morphology of the gibbsite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and laser particle size analyzer. The particle size distribution and morphology of the gibbsite were significantly influenced by the experimental conditions. The gibbsite had a mean particle size (d50) of 16.72μm. The thermal decomposition of the gibbsite was analyzed by XRD and the decomposition path was determined. The obtained coarseα-Al2O3 precipitate, which contains 0.08% Cr2O3 and 0.10% K2O, was suitable for subsequent utilization.
基金Supported by the Innovation Team Fund of Nanjing University of Aeronautics and Astronauticsthe Chinese Medical Association Research Project(S10)~~
文摘An objectifying system for color inspections of traditional Chinese medicine (CITCM) is developed. The entire system includes two parts : The hardware and the software. The hardware is an image acquiring device under a standard lighting condition, and it mainly includes a xenon lamp with color temperature of 5 500 K as light source, an integrating sphere used for diffusing light and a high resolution CCD camera. The software is used for digital image processing, and the procedure is divided into three steps. Firstly the skin/non-skin classifi- cation is performed by utilizing the threshold in chrominance channels of the RGB color space. Secondly, the fa- cial features are localized by using the image segmentation and coordinates sorting. Finally, the facial special re- gion(SR) corresponding to five internal organs is achieved by utilizing masks designed to take advantage of mor- phology. Subsequently, the chromaticity is calculated. The system is tested by taking 83 samples of 30 young and 53 elderly people. The experiment shows that there is significant difference of all SRs between the young and the elderly, and the system has better performance for objectifying research of CITCM.
文摘An integer distance graph is a graph G(Z, D) with the integer set Z as vertexset, in which an edge joining two vertices u and v if and only if | u - v | ∈ D, where D is a setof natural numbers. Using a related theorem in combinatorics and some conclusions known to us in thecoloring of the distance graph, the chromatic number _X(G) is determined in this paper that is ofthe distance graph G(Z, D) for some finite distance sets D containing {2, 3} with D = 4 andcontaining {2, 3, 5} with | D | = 5 by the method in which the combination of a few periodiccolorings.
基金The National Natural Science Foundation of China(No60573139)the Innovation Foundation of Xidian University forGraduates (No05008)
文摘A new regression algorithm of an adaptive reduced relevance vector machine is proposed to estimate the illumination chromaticity of an image for the purpose of color constancy. Within the framework of sparse Bayesian learning, the algorithm extends the relevance vector machine by combining global and local kernels adaptively in the form of multiple kernels, and the improved locality preserving projection (LLP) is then applied to reduce the column dimension of the multiple kernel input matrix to achieve less training time. To estimate the illumination chromaticity, the algorithm is trained by fuzzy central values of chromaticity histograms of a set of images and the corresponding illuminants. Experiments with real images indicate that the proposed algorithm performs better than the support vector machine and the relevance vector machine while requiring less training time than the relevance vector machine.
文摘In this paper, using the properties of chromatic polynomial, we discuss the color-partition of the complement of lK 1∪(∪C u i),and characterize the graph with the same color-partition as the class graph under u i≠4k+2.
文摘A graph is called star extremal if its fractional chromatic number is equal to its circular chromatic number. We first give a necessary and sufficient condition for a graph G to have circular chromatic number V(G)/α(G) (where V(G) is the vertex number of G and α(G) is its independence number). From this result, we get a necessary and sufficient condition for a vertex-transitive graph to be star extremal as well as a necessary and sufficient condition for a circulant graph to be star extremal. Using these conditions, we obtain several classes of star extremal graphs.
文摘Chromatic adaptation of human eyes to complex field is investigated using binocular asymmetric matching method. The results show that the leve of chromatic adapta- tion mainly depends on the average color of adapting field, whereas no obvious change oc- curs when the number of hues and their color differences vary in a complex field. The shifts of perceived color evoked by chromatic adaptation in CIE 1976 L U V color space are approximately proportional to the average color difference between the adapting field and reference field.
基金Supported by Black Tea Team of Department of National Tea Industry and Technology System(CARS-23)Key Team of Department of Agriculture of Zhejiang Province(2011006)~~
文摘Effects of varieties on the content of tea pigment, L*, a* and b* value of chromatic aberration of black tea infusion was studied. The correlation relationship between content of TF, TR, TB and L*, a*, b* value was extremely significant at P<0.05. Fresh tea leaves with plucking standard of 1 bud and 2 leaves could man-ufacture black tea with higher content of tea pigment, higher a* and b* value but lower L* value, than those of plucking standard of 1 bud and 3 leaves. But the discrepancy of certain parameter of the two plucking standards changed with vari-eties. Varieties’ quality potential could be concealed by improper plucking standards. Six varieties were divided into four groups on the basis of gross tea polyphenols in fresh tea leaves (GTP), consumption of tea polyphenols to gross tea polyphenols ratio (CTP/GTP) and gross tea pigment to consumption of tea polyphenols ratio (GP/CTP). Hybrid performed the very suitability of black tea manufacturing. To en-sure high quality of made black tea, suitable variety should be chosen and reason-able plucking standard also should be taken into consideration.
基金Project(2009GK2003)supported by the Natural Science Foundation of Hunan Province,China
文摘An oxidizing roasting process of carbon ferrochrome to prepare sodium chromate in the presence of sodium carbonate and air was investigated. The effects of reaction temperature, reaction time, mole ratio of sodium carbonate to carbon ferrochrome were studied, and thermodynamics and kinetics of the reaction were also discussed. It was observed that there was a sudden increase in reaction rate when the temperature rose to a certain value, and the sample with a smaller grain size could start the sudden increase at a lower temperature. The chromium recovery rate increased with the increase of mole ratio of sodium carbonate to carbon ferrochrome, and it reached up to 99.34% when mole ratio of sodium carbonate to carbon ferrochrome increased to 1.2:1. The chromium residue yielded from this method was only about 1/3 of the product. Moreover, the content of Fe in the residue was as high as 60.41%. Therefore, it can be easily recovered to produce sponge iron, realizing complete detoxication and zero-emission of chromium residue.
文摘In this paper, using the properties of chromatic polynomial, we discuss the color-partition of the complement of lK 1∪(∪C u i),and characterize the graph with the same color-partition as the class graph under u i≠4k+2.