A new hot mixed epoxy asphalt system was developed. The reaction process of epoxy resin was characterized by Fourier transform infrared spectroscopy (FTIR). The viscosity was investigated by Brinell viscometer when ep...A new hot mixed epoxy asphalt system was developed. The reaction process of epoxy resin was characterized by Fourier transform infrared spectroscopy (FTIR). The viscosity was investigated by Brinell viscometer when epoxy resin was mixed with asphalt. The glass transition temperature (Tg), homogeneity, thermal stability and viscoelasticity of epoxy asphalt were analyzed by differential scanning calorimetry (DSC), metallographic microscope, thermogravimetric (TG) and dynamic mechanical analysis (DMA). The results showed that the viscosity of epoxy resin modified asphalt reached 1000 mPa·s for more than 180 minutes at 180 ℃, while the best construction process is mixing at 180 ℃ for 2 hours and curing at 60 ℃ for 4 days. The particle size of asphalt is less than 50 μm. In addition, the mechanical properties of the materials are uniform within the specified pavement thickness.展开更多
In this study,the Heishan coal was used to prepare a series of activated carbon(AC)samples via a vapor deposition method.The effects of the Fe(NO_(3))3/coal weight ratio on the physicochemical properties of the activa...In this study,the Heishan coal was used to prepare a series of activated carbon(AC)samples via a vapor deposition method.The effects of the Fe(NO_(3))3/coal weight ratio on the physicochemical properties of the activated carbon were systematically investigated,and the AC samples were analyzed by the N2 adsorption-desorption technique,the scanning electron microscopy,the X-ray diffraction,the Raman spectroscopy,and the Fourier transform infrared spectroscopy.Furthermore,the adsorption properties of ethyl acetate were investigated.The results indicated that as the Fe(NO_(3))3/coal mass ratio increased from 1:8 to 1:2,the specific surface area,the total pore volume and the micropore volume initially increased and then decreased.The specific surface area increased from 560.86 m^(2)/g to 685.90 m^(2)/g,and then decreased to 299.56 m^(2)/g.The total pore volume and micropore volume increased from 0.29 cm^(3)/g and 0.17 cm^(3)/g to 0.30 cm^(3)/g and 0.22 cm^(3)/g,and then decreased to 0.16 cm^(3)/g and 0.10 cm^(3)/g,respectively.The optimized ratio was 1:8.During the activation process,iron ions infiltrated the activated carbon to promote the development of the pore structure,the pore size of which was between 2.5 nm and 3 nm in daimeter.This approach could enhance the capacity for adsorption of ethyl acetate.It is worth noting that the ACs displaying the largest specific surface area and total pore volume(685.90 m^(2)/g and 0.30 cm^(3)/g)were formed under the optimized activation conditions(950℃,20%(volume)of CO_(2),ratio 1:5),and the maximum AC capacity for adsorption of ethyl acetate was 962.62 mg/g.After seven repeated thermal regeneration experiments,the saturated AC adsorption capacity was still above 90%.展开更多
In this study,aquatic toxic effect of atrazine,and nano-CeO2,the accumulation,reproduction and adsorp-tion of atrazine onto nano-CeO2 and the facilitated transport of atrazine into D.magna by nano-CeO2 were exam-ined....In this study,aquatic toxic effect of atrazine,and nano-CeO2,the accumulation,reproduction and adsorp-tion of atrazine onto nano-CeO2 and the facilitated transport of atrazine into D.magna by nano-CeO2 were exam-ined.The results showed that atrazine concentrations of 3.0,4.0,and 10.0 mg/L exhibited 43%,56%,68% mortali-ties,respectively,which indicated the mortality was 56% while the concentration of nano-CeO2 was 4.0 mg/L.D.magna accumulated considerably more atrazine when exposed to atrazine-contaminated water in the presence of nano-CeO2.At the same time,atrazine and nano-CeO2 yielded a significant reduction of the reproduction rate at all concentrations tested.What is more,the co-exposure of nano-CeO2 and atrazine was observed to significantly de-crease the reproduction rate of D.magna,and atrazine adsorbed on nano-CeO2 quickly.Therefore,attention should be paid to their associations with other contaminants for the risk assessment of nano-CeO2 and it is worthy of notice that the sorption of atrazine on nano-CeO2 would enhance the toxicity of atrazine to D.magna.展开更多
For the applications of aqueous Li-ion hybrid capacitors and Na-ion hybrid capacitors,potassium ions are pre-inserted into MnO2 tunnel structure,the as-prepared K1.04Mn8 O16 materials consist of nanoparticles and nano...For the applications of aqueous Li-ion hybrid capacitors and Na-ion hybrid capacitors,potassium ions are pre-inserted into MnO2 tunnel structure,the as-prepared K1.04Mn8 O16 materials consist of nanoparticles and nanorods were prepared by facile high-temperature solid-state reaction.The as-prepared materials were well studied and they show outstanding electrochemical behavior.We assembled hybrid supercapacitors with commercial activated carbon(YEC-8 A)as anode and K1.04Mn8 O16 as cathode.It shows high energy and power densities.Li-ion capacitors reach a high energy density of 127.61 Wh kg-1 at the power density of 99.86 W kg-1 and Na-ion capacitor obtains 170.96 Wh kg-1 at 133.79 W kg-1.In addition,the hybrid supercapacitors demonstrate excellent cycling performance which maintain 97%capacitance retention for Li-ion capacitor and 85%for Na-ion capacitor after 10,000 cycles.展开更多
The full-potential linear augmented plane wave method based on density functional theory is employed to investigate the electronic structure of BaSi 2 . With the constant relaxation time and rigid band approximation,t...The full-potential linear augmented plane wave method based on density functional theory is employed to investigate the electronic structure of BaSi 2 . With the constant relaxation time and rigid band approximation,the electrical conductivity,Seebeck coefficient and figure of merit are calculated by using Boltzmann transport theory,further evaluated as a function of carrier concentration. We find that the Seebeck coefficient is more anisotropic than electrical conductivity. The figure of merit of BaSi 2 is predicted to be quite high at room temperature,implying that optimal doping may be an effective way to improve thermoelectric properties.展开更多
This article gives an adequate observation and analysis of polysystem theory,one of the most influential schools in translation studies put forward by Itamar Even - Zohar and developed by Gideon Toury,and discusses it...This article gives an adequate observation and analysis of polysystem theory,one of the most influential schools in translation studies put forward by Itamar Even - Zohar and developed by Gideon Toury,and discusses its application to Chinese translation phenomena in certain historical periods.展开更多
A series of biopolymer based complex were manufactured by coordinating iron ions to the abundant amino- and sulfur-containing groups in the modified wool and used as heterogeneous Fenton-like photocatalyst for 4-chlor...A series of biopolymer based complex were manufactured by coordinating iron ions to the abundant amino- and sulfur-containing groups in the modified wool and used as heterogeneous Fenton-like photocatalyst for 4-chlorophenol(4-CP) degradation in the presence of H_2O_2.Hydroxylamine hydrochloride(NH_2OH·HC1) or acrylic acid was employed to modify the natural wool to strengthen the interaction with iron and to reinforce the structural stability.The NH_2OH·HC1 modified wool based complex showed the best catalytic performance for 4-CP degradation.The strong coordination between iron and great number of hydroxamic acid in this modified complex leads to the least iron leaching during the tests.HO· species was confirmed to be the dominant reactive oxidant in the decontamination process.The approach presented in this study can provide a new approach for developing novel bioployermer-based photocatalysts for efficient degradation of toxic organic pollutants such as 4-CP.展开更多
The spin-1/2 Heisenberg chain coupled to a spin-S impurity moment with anti-periodic boundary condition is studied via the off-diagonal Bethe ansatz method.The twisted boundary breaks the U(1)symmetry of the system,wh...The spin-1/2 Heisenberg chain coupled to a spin-S impurity moment with anti-periodic boundary condition is studied via the off-diagonal Bethe ansatz method.The twisted boundary breaks the U(1)symmetry of the system,which leads to that the spin ring with impurity can not be solved by the conventional Bethe ansatz methods.By combining the properties of the R-matrix,the transfer matrix,and the quantum determinant,we derive the T–Q relation and the corresponding Bethe ansatz equations.The residual magnetizations of the ground states and the impurity specific heat are investigated.It is found that the residual magnetizations in this model strongly depend on the constraint of the topological boundary condition,the inhomogeneity of the impurity comparing with the hosts could depress the impurity specific heat in the thermodynamic limit.This method can be expand to other integrable impurity models without U(1)symmetry.展开更多
[Objectives]The paper was to find the diseases and insect pests in the process of cotton growth quickly,effectively and timely.[Methods]The growth process of cotton was dynamically monitored by UAV aerial photography,...[Objectives]The paper was to find the diseases and insect pests in the process of cotton growth quickly,effectively and timely.[Methods]The growth process of cotton was dynamically monitored by UAV aerial photography,and the aerial data map was converted into geotif image with longitude and latitude and then inputted into the detection system for preprocessing,mainly for image feature extraction and classification.Through deep learning of MATLAB software and BP neural network algorithm,the feature similarity of the images in the established characteristic database of cotton diseases and insect pests was compared.[Results]Through comparative analysis of characteristics of a large number of diseases and insect pests,it was found that deep learning method had high discrimination accuracy and good reliability.[Conclusions]The dynamic detection system using deep learning can well find cotton diseases and insect pests,and achieve early detection and early treatment,so as to effectively improve the yield and quality of cotton.展开更多
Context Theory have been extensively used in the teaching of minority English majors. Meanwhile, teachers of English in China have been inevitably involved in language testing of various types, either to choose an app...Context Theory have been extensively used in the teaching of minority English majors. Meanwhile, teachers of English in China have been inevitably involved in language testing of various types, either to choose an appropriate existing language test or design by themselves. Therefore it is of practical significance to testify whether the course taken under the Context Theory has enabled teachers to become competent in the design, development, and use of language tests. The main purpose of the present study is to analyze the quality of English grammar paper to check whether minority English majors' management of English grammar have been improved.展开更多
Fabricating SiC ceramics via the digital light processing(DLP)technology is of great challenge due to strong light absorption and high refractive index of deep-colored SiC powders,which highly differ from those of res...Fabricating SiC ceramics via the digital light processing(DLP)technology is of great challenge due to strong light absorption and high refractive index of deep-colored SiC powders,which highly differ from those of resin,and thus significantly affect the curing performance of the photosensitive SiC slurry.In this paper,a thin silicon oxide(SiO_(2))layer was in-situ formed on the surface of SiC powders by pre-oxidation treatment.This method was proven to effectively improve the curing ability of SiC slurry.The SiC photosensitive slurry was fabricated with solid content of 55 vol%and viscosity of 7.77 Pa·s(shear rate of 30 s^(−1)).The curing thickness was 50μm with exposure time of only 5 s.Then,a well-designed sintering additive was added to completely convert low-strength SiO_(2) into mullite reinforcement during sintering.Complexshaped mullite-bond SiC ceramics were successfully fabricated.The flexural strength of SiC ceramics sintered at 1550℃in air reached 97.6 MPa with porosity of 39.2 vol%,as high as those prepared by spark plasma sintering(SPS)techniques.展开更多
Graph coloring is an important tool in the study of optimization,computer science,network design,e.g.,file transferring in a computer network,pattern matching,computation of Hessians matrix and so on.In this paper,we ...Graph coloring is an important tool in the study of optimization,computer science,network design,e.g.,file transferring in a computer network,pattern matching,computation of Hessians matrix and so on.In this paper,we consider one important coloring,vertex coloring of a total graph,which is also called total coloring.We consider a planar graph G with maximum degree Δ(G)≥8,and proved that if G contains no adjacent i,j-cycles with two chords for some i,j∈{5,6,7},then G is total-(Δ+1)-colorable.展开更多
Let G be a graph, and k a positive integer. A graph G is fractional independent-set-deletable k-factor-critical(in short, fractional ID-k-factor-critical) if G-I has a fractional k-factor for every independent set I o...Let G be a graph, and k a positive integer. A graph G is fractional independent-set-deletable k-factor-critical(in short, fractional ID-k-factor-critical) if G-I has a fractional k-factor for every independent set I of G. In this paper, we present a sufficient condition for a graph to be fractional ID-k-factor-critical,depending on the minimum degree and the neighborhoods of independent sets. Furthermore, it is shown that this result in this paper is best possible in some sense.展开更多
Electrocardiogram(ECG)biometric recognition has emerged as a hot research topic in the past decade.Although some promising results have been reported,especially using sparse representation learning(SRL)and deep neural...Electrocardiogram(ECG)biometric recognition has emerged as a hot research topic in the past decade.Although some promising results have been reported,especially using sparse representation learning(SRL)and deep neural network,robust identification for small-scale data is still a challenge.To address this issue,we integrate SRL into a deep cascade model,and propose a multi-scale deep cascade bi-forest(MDCBF)model for ECG biometric recognition.We design the bi-forest based feature generator by fusing L1-norm sparsity and L2-norm collaborative representation to efficiently deal with noise.Then we propose a deep cascade framework,which includes multi-scale signal coding and deep cascade coding.In the former,we design an adaptive weighted pooling operation,which can fully explore the discriminative information of segments with low noise.In deep cascade coding,we propose level-wise class coding without backpropagation to mine more discriminative features.Extensive experiments are conducted on four small-scale ECG databases,and the results demonstrate that the proposed method performs competitively with state-of-the-art methods.展开更多
A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge.In this paper,we prove that every 1-planar graph G with maximum degree Δ(G)≥12 and girth at least five is to...A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge.In this paper,we prove that every 1-planar graph G with maximum degree Δ(G)≥12 and girth at least five is totally(Δ(G)+1)-colorable.展开更多
A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge. In this paper, we verify the total coloring conjecture for every 1-planar graph G if either ?(G) ≥ 9 and g(...A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge. In this paper, we verify the total coloring conjecture for every 1-planar graph G if either ?(G) ≥ 9 and g(G) ≥ 4, or ?(G) ≥ 7 and g(G) ≥ 5, where ?(G) is the maximum degree of G and g(G) is the girth of G.展开更多
A k-total-coloring of a graph G is a coloring of vertices and edges of G using k colors such that no two adjacent or incident elements receive the same color.In this paper,it is proved that if G is a planar graph with...A k-total-coloring of a graph G is a coloring of vertices and edges of G using k colors such that no two adjacent or incident elements receive the same color.In this paper,it is proved that if G is a planar graph with Δ(G) ≥ 7 and without chordal 7-cycles,then G has a(Δ(G) + 1)-total-coloring.展开更多
A facile transformation of alkynes into α-amino ketones by an N-bromosuccinimide-mediated one-pot cascade strategy is described. A variety of α-amino ketones are obtained in moderate to good yields under mild condit...A facile transformation of alkynes into α-amino ketones by an N-bromosuccinimide-mediated one-pot cascade strategy is described. A variety of α-amino ketones are obtained in moderate to good yields under mild conditions. To overcome the multi-step synthesis, N-bromosuccinimide is involved in multiple tasks, playing a key role in the reaction course.展开更多
基金Funded by the Fundamental Research Funds for the Central Universities (No.195201039)National Science Foundation of China (Nos.51472189 and 51373129)
文摘A new hot mixed epoxy asphalt system was developed. The reaction process of epoxy resin was characterized by Fourier transform infrared spectroscopy (FTIR). The viscosity was investigated by Brinell viscometer when epoxy resin was mixed with asphalt. The glass transition temperature (Tg), homogeneity, thermal stability and viscoelasticity of epoxy asphalt were analyzed by differential scanning calorimetry (DSC), metallographic microscope, thermogravimetric (TG) and dynamic mechanical analysis (DMA). The results showed that the viscosity of epoxy resin modified asphalt reached 1000 mPa·s for more than 180 minutes at 180 ℃, while the best construction process is mixing at 180 ℃ for 2 hours and curing at 60 ℃ for 4 days. The particle size of asphalt is less than 50 μm. In addition, the mechanical properties of the materials are uniform within the specified pavement thickness.
基金The authors thank the National Natural Science Foundation of China(No.51906130)the Natural Science Foundation of Shandong Province(No.ZR2019BEE053)+1 种基金the Key R&D and Development Plan of Shandong Province(2020CXGC011401)the Foundation of Shandong Key Lab of Energy Carbon Reduction and Resource Utilization,Shandong University(No.ECRRU201804)for the financial support.
文摘In this study,the Heishan coal was used to prepare a series of activated carbon(AC)samples via a vapor deposition method.The effects of the Fe(NO_(3))3/coal weight ratio on the physicochemical properties of the activated carbon were systematically investigated,and the AC samples were analyzed by the N2 adsorption-desorption technique,the scanning electron microscopy,the X-ray diffraction,the Raman spectroscopy,and the Fourier transform infrared spectroscopy.Furthermore,the adsorption properties of ethyl acetate were investigated.The results indicated that as the Fe(NO_(3))3/coal mass ratio increased from 1:8 to 1:2,the specific surface area,the total pore volume and the micropore volume initially increased and then decreased.The specific surface area increased from 560.86 m^(2)/g to 685.90 m^(2)/g,and then decreased to 299.56 m^(2)/g.The total pore volume and micropore volume increased from 0.29 cm^(3)/g and 0.17 cm^(3)/g to 0.30 cm^(3)/g and 0.22 cm^(3)/g,and then decreased to 0.16 cm^(3)/g and 0.10 cm^(3)/g,respectively.The optimized ratio was 1:8.During the activation process,iron ions infiltrated the activated carbon to promote the development of the pore structure,the pore size of which was between 2.5 nm and 3 nm in daimeter.This approach could enhance the capacity for adsorption of ethyl acetate.It is worth noting that the ACs displaying the largest specific surface area and total pore volume(685.90 m^(2)/g and 0.30 cm^(3)/g)were formed under the optimized activation conditions(950℃,20%(volume)of CO_(2),ratio 1:5),and the maximum AC capacity for adsorption of ethyl acetate was 962.62 mg/g.After seven repeated thermal regeneration experiments,the saturated AC adsorption capacity was still above 90%.
基金supported by Chongqing Key Laboratory of Micro/Nano Materials Engineering and Technology (No. KFJJ1106)Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection (No.JLCBE11004)Jiangsu Marine Resources Development Research Institute (No. JSIMR10E04)
文摘In this study,aquatic toxic effect of atrazine,and nano-CeO2,the accumulation,reproduction and adsorp-tion of atrazine onto nano-CeO2 and the facilitated transport of atrazine into D.magna by nano-CeO2 were exam-ined.The results showed that atrazine concentrations of 3.0,4.0,and 10.0 mg/L exhibited 43%,56%,68% mortali-ties,respectively,which indicated the mortality was 56% while the concentration of nano-CeO2 was 4.0 mg/L.D.magna accumulated considerably more atrazine when exposed to atrazine-contaminated water in the presence of nano-CeO2.At the same time,atrazine and nano-CeO2 yielded a significant reduction of the reproduction rate at all concentrations tested.What is more,the co-exposure of nano-CeO2 and atrazine was observed to significantly de-crease the reproduction rate of D.magna,and atrazine adsorbed on nano-CeO2 quickly.Therefore,attention should be paid to their associations with other contaminants for the risk assessment of nano-CeO2 and it is worthy of notice that the sorption of atrazine on nano-CeO2 would enhance the toxicity of atrazine to D.magna.
基金financially supported by the Fundamental Research Funds of Shangdong University(2016JC005,2017JC042,2017JC010)High-level Talents’Discipline Construction Fund of Shandong University(31370089963078)+1 种基金Technology Major Project(2017CXGC1010,2018JMRH0211,ZR2017MEM002)School research startup expenses of Harbin Institute of Technology(Shenzhen)(DD29100027)。
文摘For the applications of aqueous Li-ion hybrid capacitors and Na-ion hybrid capacitors,potassium ions are pre-inserted into MnO2 tunnel structure,the as-prepared K1.04Mn8 O16 materials consist of nanoparticles and nanorods were prepared by facile high-temperature solid-state reaction.The as-prepared materials were well studied and they show outstanding electrochemical behavior.We assembled hybrid supercapacitors with commercial activated carbon(YEC-8 A)as anode and K1.04Mn8 O16 as cathode.It shows high energy and power densities.Li-ion capacitors reach a high energy density of 127.61 Wh kg-1 at the power density of 99.86 W kg-1 and Na-ion capacitor obtains 170.96 Wh kg-1 at 133.79 W kg-1.In addition,the hybrid supercapacitors demonstrate excellent cycling performance which maintain 97%capacitance retention for Li-ion capacitor and 85%for Na-ion capacitor after 10,000 cycles.
基金supported by the National Basic Research Program of China (Grant No.2007CB607504)Graduate Independent Innovation Foundation of Shandong University (Grant No.yzc09076)
文摘The full-potential linear augmented plane wave method based on density functional theory is employed to investigate the electronic structure of BaSi 2 . With the constant relaxation time and rigid band approximation,the electrical conductivity,Seebeck coefficient and figure of merit are calculated by using Boltzmann transport theory,further evaluated as a function of carrier concentration. We find that the Seebeck coefficient is more anisotropic than electrical conductivity. The figure of merit of BaSi 2 is predicted to be quite high at room temperature,implying that optimal doping may be an effective way to improve thermoelectric properties.
文摘This article gives an adequate observation and analysis of polysystem theory,one of the most influential schools in translation studies put forward by Itamar Even - Zohar and developed by Gideon Toury,and discusses its application to Chinese translation phenomena in certain historical periods.
基金National Natural Science Foundation of China (grant nos.51268001,21303141) for support of this work
文摘A series of biopolymer based complex were manufactured by coordinating iron ions to the abundant amino- and sulfur-containing groups in the modified wool and used as heterogeneous Fenton-like photocatalyst for 4-chlorophenol(4-CP) degradation in the presence of H_2O_2.Hydroxylamine hydrochloride(NH_2OH·HC1) or acrylic acid was employed to modify the natural wool to strengthen the interaction with iron and to reinforce the structural stability.The NH_2OH·HC1 modified wool based complex showed the best catalytic performance for 4-CP degradation.The strong coordination between iron and great number of hydroxamic acid in this modified complex leads to the least iron leaching during the tests.HO· species was confirmed to be the dominant reactive oxidant in the decontamination process.The approach presented in this study can provide a new approach for developing novel bioployermer-based photocatalysts for efficient degradation of toxic organic pollutants such as 4-CP.
基金National Natural Science Foundation of China(Grant No.11664001).
文摘The spin-1/2 Heisenberg chain coupled to a spin-S impurity moment with anti-periodic boundary condition is studied via the off-diagonal Bethe ansatz method.The twisted boundary breaks the U(1)symmetry of the system,which leads to that the spin ring with impurity can not be solved by the conventional Bethe ansatz methods.By combining the properties of the R-matrix,the transfer matrix,and the quantum determinant,we derive the T–Q relation and the corresponding Bethe ansatz equations.The residual magnetizations of the ground states and the impurity specific heat are investigated.It is found that the residual magnetizations in this model strongly depend on the constraint of the topological boundary condition,the inhomogeneity of the impurity comparing with the hosts could depress the impurity specific heat in the thermodynamic limit.This method can be expand to other integrable impurity models without U(1)symmetry.
基金Supported by Natural Science Foundation of Xinjiang Uygur Autonomous Region(2020D01C003)。
文摘[Objectives]The paper was to find the diseases and insect pests in the process of cotton growth quickly,effectively and timely.[Methods]The growth process of cotton was dynamically monitored by UAV aerial photography,and the aerial data map was converted into geotif image with longitude and latitude and then inputted into the detection system for preprocessing,mainly for image feature extraction and classification.Through deep learning of MATLAB software and BP neural network algorithm,the feature similarity of the images in the established characteristic database of cotton diseases and insect pests was compared.[Results]Through comparative analysis of characteristics of a large number of diseases and insect pests,it was found that deep learning method had high discrimination accuracy and good reliability.[Conclusions]The dynamic detection system using deep learning can well find cotton diseases and insect pests,and achieve early detection and early treatment,so as to effectively improve the yield and quality of cotton.
文摘Context Theory have been extensively used in the teaching of minority English majors. Meanwhile, teachers of English in China have been inevitably involved in language testing of various types, either to choose an appropriate existing language test or design by themselves. Therefore it is of practical significance to testify whether the course taken under the Context Theory has enabled teachers to become competent in the design, development, and use of language tests. The main purpose of the present study is to analyze the quality of English grammar paper to check whether minority English majors' management of English grammar have been improved.
基金supported by Shandong University−MSEA International Institute for Materials Genome Joint Innovation Center for Advanced Ceramics,and the Key Research and Development Projects of Shaanxi Province(Nos.2018ZDCXLGY-09-06 and 2021ZDLGY14-06).
文摘Fabricating SiC ceramics via the digital light processing(DLP)technology is of great challenge due to strong light absorption and high refractive index of deep-colored SiC powders,which highly differ from those of resin,and thus significantly affect the curing performance of the photosensitive SiC slurry.In this paper,a thin silicon oxide(SiO_(2))layer was in-situ formed on the surface of SiC powders by pre-oxidation treatment.This method was proven to effectively improve the curing ability of SiC slurry.The SiC photosensitive slurry was fabricated with solid content of 55 vol%and viscosity of 7.77 Pa·s(shear rate of 30 s^(−1)).The curing thickness was 50μm with exposure time of only 5 s.Then,a well-designed sintering additive was added to completely convert low-strength SiO_(2) into mullite reinforcement during sintering.Complexshaped mullite-bond SiC ceramics were successfully fabricated.The flexural strength of SiC ceramics sintered at 1550℃in air reached 97.6 MPa with porosity of 39.2 vol%,as high as those prepared by spark plasma sintering(SPS)techniques.
基金Supported by National Natural Science Foundation of China(Grants Nos.11401386,11402075,11501316,71171120 and 71571180)China Postdoctoral Science Foundation(Grants Nos.2015M570568,2015M570572)+2 种基金the Qingdao Postdoctoral Application Research Project(Grants Nos.2015138,2015170)the Shandong Provincial Natural Science Foundation of China(Grants Nos.ZR2013AM001,ZR2014AQ001,ZR2015GZ007,ZR2015FM023)the Scientific Research Program of the Higher Education Institution of Xinjiang(Grant No.XJEDU20141046)
文摘Graph coloring is an important tool in the study of optimization,computer science,network design,e.g.,file transferring in a computer network,pattern matching,computation of Hessians matrix and so on.In this paper,we consider one important coloring,vertex coloring of a total graph,which is also called total coloring.We consider a planar graph G with maximum degree Δ(G)≥8,and proved that if G contains no adjacent i,j-cycles with two chords for some i,j∈{5,6,7},then G is total-(Δ+1)-colorable.
基金supported by the National Natural Science Foundation of China(Grant No.11371009,11501256,61503160)Six Big Talent Peak of Jiangsu Province(Grant No.JY–022)+3 种基金333 Project of Jiangsu Provincethe National Social Science Foundation of China(Grant No.14AGL001)the Natural Science Foundation of Xinjiang Province of China(Grant No.2015211A003)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(Grant No.14KJD110002)
文摘Let G be a graph, and k a positive integer. A graph G is fractional independent-set-deletable k-factor-critical(in short, fractional ID-k-factor-critical) if G-I has a fractional k-factor for every independent set I of G. In this paper, we present a sufficient condition for a graph to be fractional ID-k-factor-critical,depending on the minimum degree and the neighborhoods of independent sets. Furthermore, it is shown that this result in this paper is best possible in some sense.
基金supported in part by the NSFC-Xinjiang Joint Fund under Grant No.U1903127in part by the Natural Science Foundation of Shandong Province under Grant No.ZR2020MF052。
文摘Electrocardiogram(ECG)biometric recognition has emerged as a hot research topic in the past decade.Although some promising results have been reported,especially using sparse representation learning(SRL)and deep neural network,robust identification for small-scale data is still a challenge.To address this issue,we integrate SRL into a deep cascade model,and propose a multi-scale deep cascade bi-forest(MDCBF)model for ECG biometric recognition.We design the bi-forest based feature generator by fusing L1-norm sparsity and L2-norm collaborative representation to efficiently deal with noise.Then we propose a deep cascade framework,which includes multi-scale signal coding and deep cascade coding.In the former,we design an adaptive weighted pooling operation,which can fully explore the discriminative information of segments with low noise.In deep cascade coding,we propose level-wise class coding without backpropagation to mine more discriminative features.Extensive experiments are conducted on four small-scale ECG databases,and the results demonstrate that the proposed method performs competitively with state-of-the-art methods.
基金supported by National Natural Science Foundation of China(Grant No.11271006)
文摘A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge.In this paper,we prove that every 1-planar graph G with maximum degree Δ(G)≥12 and girth at least five is totally(Δ(G)+1)-colorable.
基金Supported by the scientific research program of Xinjiang Uygur Autonomous Region grant 2016D01C012 the Scientific Research Program(XJEDU2016I046)of the Higher Education Institution of Xinjiang
文摘A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge. In this paper, we verify the total coloring conjecture for every 1-planar graph G if either ?(G) ≥ 9 and g(G) ≥ 4, or ?(G) ≥ 7 and g(G) ≥ 5, where ?(G) is the maximum degree of G and g(G) is the girth of G.
基金Supported by National Natural Science Foundation of China(Grant No.11271006)
文摘A k-total-coloring of a graph G is a coloring of vertices and edges of G using k colors such that no two adjacent or incident elements receive the same color.In this paper,it is proved that if G is a planar graph with Δ(G) ≥ 7 and without chordal 7-cycles,then G has a(Δ(G) + 1)-total-coloring.
基金the Natural Science Foundation of Xinjiang Province(No. 2016D01C009)the Educational Commission of Xinjiang(No. XJEDU2017S053)for financial support
文摘A facile transformation of alkynes into α-amino ketones by an N-bromosuccinimide-mediated one-pot cascade strategy is described. A variety of α-amino ketones are obtained in moderate to good yields under mild conditions. To overcome the multi-step synthesis, N-bromosuccinimide is involved in multiple tasks, playing a key role in the reaction course.
