Fe/C multilayer thin films were deposited by magnetron sputtering. Small angle X-ray diffraction measurements show very well periodicity of the samples. The modulation period determined from a modified Bragg equation ...Fe/C multilayer thin films were deposited by magnetron sputtering. Small angle X-ray diffraction measurements show very well periodicity of the samples. The modulation period determined from a modified Bragg equation agrees well with that determined from deposition rate. The interfacial roughness parameter ξof several samples calculated by X-ray diffraction is between 3.5(?) and 5.6(?).展开更多
Tin dioxide(SnO_(2))with a high theoretical specific capacity of 1494 mAh g^(-1)is a promising candidate anode material for lithium storage.However,the shortcomings of serious volume expansion and low conductivity lim...Tin dioxide(SnO_(2))with a high theoretical specific capacity of 1494 mAh g^(-1)is a promising candidate anode material for lithium storage.However,the shortcomings of serious volume expansion and low conductivity limit its wide application.Herein,coaxial nano-multilayered C/SnO_(2)/TiO_(2)composites were fabricated via layerby-layer self-assembly of TiO_(2)and SnO_(2)-gel layers on the natural cellulose filter paper,followed by thermal treatment under a nitrogen atmosphere.Through engineering design of the assembly process,the optimal C/SinO_(2)/TiO_(2)composite features five alternating SnO_(2)and TiO_(2)nanolayers,with TiO_(2)as the outside shell(denoted as C/TSTST).This unique structure endows the C/TSTST with excellent structural stability and electrochemical kinetics,making it a high-performance anode for lithium-ion batteries(LIBs).The C/TSTST composite delivers a high reversible capacity of 676 mAh g^(-1)at 0.1 A g^(-1)after 200 cycles and retains a capacity of 504 mAh g^(-1)at 1.0 A g^(-1),which can be recovered to 781 mAh g^(-1)at 0.1 A g^(-1)The significantly enhanced electrochemical performance is attributed to the hierarchical hybrid structure,where the carbon core combined with coaxial TiO_(2)nanolayers serves as a structural scaffold,ameliorating volume change of SnO_(2)while creating abundant interfacial defects for enhanced lithium storage and rapid charge transport.These findings are further demonstrated by the density functional theory(DFT)calculations.This work provides an efficient strategy for designing coaxial nano-multilayered transition metal oxide-related electrode materials,offering new insights into high-performance LIBs anodes.展开更多
The S38C railway axle undergoes induction hardening,resulting in a gradient-distributed microstructure and mechanical properties.The accurate identification of gradient-distributed plastic parameters for the S38C axle...The S38C railway axle undergoes induction hardening,resulting in a gradient-distributed microstructure and mechanical properties.The accurate identification of gradient-distributed plastic parameters for the S38C axle remains a challenging task.To tackle this challenge,the present study proposes a novel approach for identifying the gradient-distributed plastic parameters for the S38C axle by integrating nano-indentation techniques with the machine learning method.Firstly,nano-indentation tests are conducted along the radial direction of the S38C axle to obtain the gradient-distributed load-displacement curves,nano-hardness,and elastic modulus.Subsequently,the dimensionless analysis is performed to obtain the representative stress,strain,and yield stress from load-displacement curves.These parameters are then incorporated into the machine learning method as physical information to identify the gradient-distributed plastic parameters of the S38C axle.The results indicate that the proposed method based on the physics-informed neural network and multi-fidelity neural network successfully identifies the gradient-distributed plastic parameters of the S38C axles and demonstrates superior prediction accuracy and generalization compared with the purely data-driven machine learning method.展开更多
The samples of the C-S-H series were synthesized by hydrothermal reaction of fumed silica, CaO and deionized water at initial C/S ratios between 1.0-1.7. Phase composition and structural and morphology characteristics...The samples of the C-S-H series were synthesized by hydrothermal reaction of fumed silica, CaO and deionized water at initial C/S ratios between 1.0-1.7. Phase composition and structural and morphology characteristics of C-S-H samples were analyzed by XRD, IR and SEM. The experimental results showed that the d-spacing of (002), (110) and (020) decreased, the d-spacing of (200) increased, and the d-spacing of (310) varied randomly, the polymerization of silica tetrahedra of C-S-H decreased, and morphology of C-S-H samples varied from sheet shapes to long reticular fibers as C/S ratio increased.展开更多
According to specifications for Welding Procedure Qualification of ASME IX Section and Chinese code, JB 4708 2000, a software package for managing welding documents has been rebuilt. Consequently, the new software pa...According to specifications for Welding Procedure Qualification of ASME IX Section and Chinese code, JB 4708 2000, a software package for managing welding documents has been rebuilt. Consequently, the new software package can be used in a Limited Area Network (LAN) with 4 different levels of authorities for different users. Therefore, the welding documents, including DWPS (Design for Welding Procedure Specifications), PQRs (Procedure Qualification Records) and WPS (Welding Procedure Specifications) can be shared within a company. At the same time, the system provides users various functions such as browsing, copying, editing, searching and printing records, and helps users to make decision of whether a new PQR test is necessary or not according to the codes above as well. Furthermore, super users can also browse the history of record modification and retrieve the records when needed.展开更多
Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effec...Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effect of S is better than that of C or N on the tunable photocatalytic activities of BiOCl. At low concentration, S-doped BiOCl systems are the most stable under Bi-rich growth conditions because of their lower impurity-formation energy. Compared with the electronic structures of S-doped BiOCl, C-or N-doped BiOCl have relatively deeper impurity energy levels appearing in their band gap(except Bi_(36)O_(35)NCl_(36)), which may act as photogenerated carrier-recombination centers and reduce photocatalytic activity. At high concentration, S is substituted on the O lattice site system, whereas some S 3p states mix with the valence band; this mixture leads to an obvious band-gap decrease and continuum-state formation above the valence-band edge of BiOCl. Such activity is advantageous to photochemical catalysis response. Compared with pure Bi OCl and a low-concentration S-doped system, a high-concentration S-doped system shows an obvious redshift on the absorption edge and has better photocatalytic O_2 evolution performance.展开更多
SiC nanowires reinforced C/(PyC-SiC)_(n)multilayered matrix composites(SM-CS for short)were prepared by combined with sol-gel and chemical vapor infiltration(CVI)method.Firstly,(PyC-Si OC);multilayered structure was f...SiC nanowires reinforced C/(PyC-SiC)_(n)multilayered matrix composites(SM-CS for short)were prepared by combined with sol-gel and chemical vapor infiltration(CVI)method.Firstly,(PyC-Si OC);multilayered structure was formed by cycles of impregnation and deposition.Then SiOC was transformed into SiC by heat-treatment,and(PyC-SiC)_(n)multilayered structure would be obtained.At the same time,the PyC layer which was designed as the outmost layer could decrease gas supersaturation to form in-situ tubular SiC nanowires on the surface of multilayered structure.The results of three-point bending test showed that the maximum force of SM-CS composites was increased by the number of cycles of the preparation process,which were up to enhanced by 74.38%compared with C/C composite materials.The fracture surface showed that the improvement was due to the multiscale reinforcing system of(PyC-SiC)_(n)multilayered structure and SiC nanowires.Multilayered structure can protect carbon fibers and release stress concentration by induction of cracks.And the mechanical interlocking effect of SiC nanowires could reinforce bonding force of the remaining matrix.展开更多
The effects of polyaerylamide (PAM) and polyvinyl alcohol (PVA) on morphology and structure of calcium silica~ hydrate with C/S 1.0-1.7 prepared via precipitation in solution were investigated by XRD, FT-IR and TE...The effects of polyaerylamide (PAM) and polyvinyl alcohol (PVA) on morphology and structure of calcium silica~ hydrate with C/S 1.0-1.7 prepared via precipitation in solution were investigated by XRD, FT-IR and TEM techniques. The results show that incorporation of the polymers decreased the order degree, increased the interlayer spacing and disturbed the layered stacking of C-S-H. Interlayer spacing expansion depended on C/S ratios and type of polymer. Interlayer spacing expansion had a minimum at C/S 1.0 and a maximum at C/S 1.3 and 1.5. Interlayer spacing expansion of PAM was bigger than that of PVA with the same C/S. C-S-H added with PVA mainly exhibited foil-like and fibrillar morphology. The fibrils were of variable length from a few tens of nanometers to a few hundreds of nanometers. Fibrils or foils seemed to be longer in the presence of PVA.展开更多
(PPh_3)_2Ni(i-mnt),(i-mnt=S_2C=C(CN)_2),Mr=613.43,monoclinic,Pn,a=9.167(3),b=10.872(3), c=18.209(7) ,β=101.46(3)°,V=1779(1) ,Z=2,Dc=1.15 g/cm^3,λ(Moka)=0.71069 ,μ=7.67 cm^(-1), F(000)=648,T=296K,final R=0.060,...(PPh_3)_2Ni(i-mnt),(i-mnt=S_2C=C(CN)_2),Mr=613.43,monoclinic,Pn,a=9.167(3),b=10.872(3), c=18.209(7) ,β=101.46(3)°,V=1779(1) ,Z=2,Dc=1.15 g/cm^3,λ(Moka)=0.71069 ,μ=7.67 cm^(-1), F(000)=648,T=296K,final R=0.060,Rw=0.073 for 1909 observed reflections with Ⅰ≥3σ(Ⅰ).The complex adopts a square planar geometry as its coordination unit,the mean Ni-S and Ni-P distances are 2.216 and 2.221 ,respectivety.展开更多
In the paper, dicalcium silicate (C2S) was modified to obtain higher performance, and the solutionizing pattern of BaSO4 in cement clinker was analyzed theoretically. According to experimental results, solutionizing o...In the paper, dicalcium silicate (C2S) was modified to obtain higher performance, and the solutionizing pattern of BaSO4 in cement clinker was analyzed theoretically. According to experimental results, solutionizing of BaSO4in cement clinker improved crystal plane distance of C2S as well as the relations of coordination. The performance tests show that the strength of C2S modified by BaSO4 changes and the reactivity of C2S increases significantly.展开更多
(CH_3C_5H_4)Zr(S_2CNBz_2)_3, Mr=987.55, space group P1, a=13.002(4), b=13.659(3), c=29.685(8); α=100.72(2)~o,β=97.23(2)~o, γ=105.36(2)~o; V=4909(2)~3, Z=4, Dc=1.34gcm^(-3), Mo-K(λ=0.71073A) radiation, μ=5.0cm^(-1...(CH_3C_5H_4)Zr(S_2CNBz_2)_3, Mr=987.55, space group P1, a=13.002(4), b=13.659(3), c=29.685(8); α=100.72(2)~o,β=97.23(2)~o, γ=105.36(2)~o; V=4909(2)~3, Z=4, Dc=1.34gcm^(-3), Mo-K(λ=0.71073A) radiation, μ=5.0cm^(-1), R=0.069, Rw=0.078 for 6100 reflections. The title complex has pentagonal bipyramid configuration in which the zirconium atom is coordinated by one CH_3C_5H_4 group and three bidentate dibenzyldithiocarbamate ligands.展开更多
Cp;ZrCl(S;CNBz;) is a five-coordinate bent zirconocene in which the dibenzyldithiocarbamate is a bidentate ligand (Zr-Cl 2.549(1)A; Zr-C 2.489-2.533; Zr-S 2.667(1), 2.734(1); Zr-Cl-S1 137.6(1);; Zr-Cl-S2 73....Cp;ZrCl(S;CNBz;) is a five-coordinate bent zirconocene in which the dibenzyldithiocarbamate is a bidentate ligand (Zr-Cl 2.549(1)A; Zr-C 2.489-2.533; Zr-S 2.667(1), 2.734(1); Zr-Cl-S1 137.6(1);; Zr-Cl-S2 73.3(1);).展开更多
The compound phenol,2-[4(S)-4,5-dihydro-4-phenyl-2-ozazolinyl(1,C15H13NO2) was synthesized with a simple,one step method free of water and air.It was obtained in a moderate yield from the reaction of 2-hydroxybenz...The compound phenol,2-[4(S)-4,5-dihydro-4-phenyl-2-ozazolinyl(1,C15H13NO2) was synthesized with a simple,one step method free of water and air.It was obtained in a moderate yield from the reaction of 2-hydroxybenzonitrile with optically active amino alcohol in chloroben-zene under dry,anaerobic conditions.It belongs to the orthorhombic system,space group P212121 with a = 5.786(5),b = 10.730(5),c = 19.722(5),C15H13NO2,Mr = 239.26,V = 1224.4(12)3,Z = 4 and Dc = 1.298 mg/m3.The final R = 0.0324 for 1627 observed reflections with Ⅰ 〉 2σ(Ⅰ) and Rw = 0.0826 for all data.The structure of compound 1 was determined by X-ray diffraction,NMR and HRMS.展开更多
文摘Fe/C multilayer thin films were deposited by magnetron sputtering. Small angle X-ray diffraction measurements show very well periodicity of the samples. The modulation period determined from a modified Bragg equation agrees well with that determined from deposition rate. The interfacial roughness parameter ξof several samples calculated by X-ray diffraction is between 3.5(?) and 5.6(?).
基金financially supported by the National Natural Science Foundation of China(Nos.22302133 and 22405161)Central Guidance on Local Science and Technology Development Fund of Hebei Province,China(No.236Z4406G)+5 种基金the Natural Science Foundation of Hebei Education Department,China(No.BJ2025100)the Natural Science Foundation of Hebei Province,China(No.B2021210001)the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2024D01A157)the Key R&D Plan of Karamay(No.2024zdyf0009)Karamay Innovation Environment Construction Plan(Innovative Talents)Project(No.2024hjcxrc0029)the Research Foundation of China University of Petroleum-Beijing at Karamay(No.XQZX20240023)
文摘Tin dioxide(SnO_(2))with a high theoretical specific capacity of 1494 mAh g^(-1)is a promising candidate anode material for lithium storage.However,the shortcomings of serious volume expansion and low conductivity limit its wide application.Herein,coaxial nano-multilayered C/SnO_(2)/TiO_(2)composites were fabricated via layerby-layer self-assembly of TiO_(2)and SnO_(2)-gel layers on the natural cellulose filter paper,followed by thermal treatment under a nitrogen atmosphere.Through engineering design of the assembly process,the optimal C/SinO_(2)/TiO_(2)composite features five alternating SnO_(2)and TiO_(2)nanolayers,with TiO_(2)as the outside shell(denoted as C/TSTST).This unique structure endows the C/TSTST with excellent structural stability and electrochemical kinetics,making it a high-performance anode for lithium-ion batteries(LIBs).The C/TSTST composite delivers a high reversible capacity of 676 mAh g^(-1)at 0.1 A g^(-1)after 200 cycles and retains a capacity of 504 mAh g^(-1)at 1.0 A g^(-1),which can be recovered to 781 mAh g^(-1)at 0.1 A g^(-1)The significantly enhanced electrochemical performance is attributed to the hierarchical hybrid structure,where the carbon core combined with coaxial TiO_(2)nanolayers serves as a structural scaffold,ameliorating volume change of SnO_(2)while creating abundant interfacial defects for enhanced lithium storage and rapid charge transport.These findings are further demonstrated by the density functional theory(DFT)calculations.This work provides an efficient strategy for designing coaxial nano-multilayered transition metal oxide-related electrode materials,offering new insights into high-performance LIBs anodes.
基金supported by the National Key Research and Development Plan(Grant No.2022YFB3401901)the National Natural Science Foundation of China(Grant Nos.12192210,12192214,12072295,and 12222209)+1 种基金Independent Project of State Key Laboratory of Rail Transit Vehicle System(Grant No.2023TPL-T03)Fundamental Research Funds for the Central Universities(Grant No.2682023CG004).
文摘The S38C railway axle undergoes induction hardening,resulting in a gradient-distributed microstructure and mechanical properties.The accurate identification of gradient-distributed plastic parameters for the S38C axle remains a challenging task.To tackle this challenge,the present study proposes a novel approach for identifying the gradient-distributed plastic parameters for the S38C axle by integrating nano-indentation techniques with the machine learning method.Firstly,nano-indentation tests are conducted along the radial direction of the S38C axle to obtain the gradient-distributed load-displacement curves,nano-hardness,and elastic modulus.Subsequently,the dimensionless analysis is performed to obtain the representative stress,strain,and yield stress from load-displacement curves.These parameters are then incorporated into the machine learning method as physical information to identify the gradient-distributed plastic parameters of the S38C axle.The results indicate that the proposed method based on the physics-informed neural network and multi-fidelity neural network successfully identifies the gradient-distributed plastic parameters of the S38C axles and demonstrates superior prediction accuracy and generalization compared with the purely data-driven machine learning method.
基金Funded by the National Basic Research Program of China (973 Program) (No. 2009CB623201)the National Natural Science Foundation of China (No.51072150)
文摘The samples of the C-S-H series were synthesized by hydrothermal reaction of fumed silica, CaO and deionized water at initial C/S ratios between 1.0-1.7. Phase composition and structural and morphology characteristics of C-S-H samples were analyzed by XRD, IR and SEM. The experimental results showed that the d-spacing of (002), (110) and (020) decreased, the d-spacing of (200) increased, and the d-spacing of (310) varied randomly, the polymerization of silica tetrahedra of C-S-H decreased, and morphology of C-S-H samples varied from sheet shapes to long reticular fibers as C/S ratio increased.
文摘According to specifications for Welding Procedure Qualification of ASME IX Section and Chinese code, JB 4708 2000, a software package for managing welding documents has been rebuilt. Consequently, the new software package can be used in a Limited Area Network (LAN) with 4 different levels of authorities for different users. Therefore, the welding documents, including DWPS (Design for Welding Procedure Specifications), PQRs (Procedure Qualification Records) and WPS (Welding Procedure Specifications) can be shared within a company. At the same time, the system provides users various functions such as browsing, copying, editing, searching and printing records, and helps users to make decision of whether a new PQR test is necessary or not according to the codes above as well. Furthermore, super users can also browse the history of record modification and retrieve the records when needed.
基金This project was supported by the China Postdoctoral Science Foundation,Henan Postdoctoral Science Foundation,NCWU 2017 Annual Teaching Teacher Training Object ProjectKey Research Projects of Higher Education in Henan Province(18B150010)+1 种基金the Key Scientific Research Project of Henan Higher Education(No.17A520011)the Science and Technology Research Project of Henan Province(182102110029)
文摘Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effect of S is better than that of C or N on the tunable photocatalytic activities of BiOCl. At low concentration, S-doped BiOCl systems are the most stable under Bi-rich growth conditions because of their lower impurity-formation energy. Compared with the electronic structures of S-doped BiOCl, C-or N-doped BiOCl have relatively deeper impurity energy levels appearing in their band gap(except Bi_(36)O_(35)NCl_(36)), which may act as photogenerated carrier-recombination centers and reduce photocatalytic activity. At high concentration, S is substituted on the O lattice site system, whereas some S 3p states mix with the valence band; this mixture leads to an obvious band-gap decrease and continuum-state formation above the valence-band edge of BiOCl. Such activity is advantageous to photochemical catalysis response. Compared with pure Bi OCl and a low-concentration S-doped system, a high-concentration S-doped system shows an obvious redshift on the absorption edge and has better photocatalytic O_2 evolution performance.
基金supported by the National Natural Science Foundation of China(Nos.51772247 and 5172780072)the Creative Research Foundation of Science and Technology on Thermostructural Composite Materials Laboratory(No.6142911050217)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2017JM5098)。
文摘SiC nanowires reinforced C/(PyC-SiC)_(n)multilayered matrix composites(SM-CS for short)were prepared by combined with sol-gel and chemical vapor infiltration(CVI)method.Firstly,(PyC-Si OC);multilayered structure was formed by cycles of impregnation and deposition.Then SiOC was transformed into SiC by heat-treatment,and(PyC-SiC)_(n)multilayered structure would be obtained.At the same time,the PyC layer which was designed as the outmost layer could decrease gas supersaturation to form in-situ tubular SiC nanowires on the surface of multilayered structure.The results of three-point bending test showed that the maximum force of SM-CS composites was increased by the number of cycles of the preparation process,which were up to enhanced by 74.38%compared with C/C composite materials.The fracture surface showed that the improvement was due to the multiscale reinforcing system of(PyC-SiC)_(n)multilayered structure and SiC nanowires.Multilayered structure can protect carbon fibers and release stress concentration by induction of cracks.And the mechanical interlocking effect of SiC nanowires could reinforce bonding force of the remaining matrix.
基金Funded by National Natural Science Foundation of China(Nos51072150,51272193)Program for New Century Excellent Talents inUniversity(No.NCET-10-0660)the Fundamental Research Fundsfor the Central Universities(Nos.2012-Ia-010,2013-Ia-015)
文摘The effects of polyaerylamide (PAM) and polyvinyl alcohol (PVA) on morphology and structure of calcium silica~ hydrate with C/S 1.0-1.7 prepared via precipitation in solution were investigated by XRD, FT-IR and TEM techniques. The results show that incorporation of the polymers decreased the order degree, increased the interlayer spacing and disturbed the layered stacking of C-S-H. Interlayer spacing expansion depended on C/S ratios and type of polymer. Interlayer spacing expansion had a minimum at C/S 1.0 and a maximum at C/S 1.3 and 1.5. Interlayer spacing expansion of PAM was bigger than that of PVA with the same C/S. C-S-H added with PVA mainly exhibited foil-like and fibrillar morphology. The fibrils were of variable length from a few tens of nanometers to a few hundreds of nanometers. Fibrils or foils seemed to be longer in the presence of PVA.
文摘(PPh_3)_2Ni(i-mnt),(i-mnt=S_2C=C(CN)_2),Mr=613.43,monoclinic,Pn,a=9.167(3),b=10.872(3), c=18.209(7) ,β=101.46(3)°,V=1779(1) ,Z=2,Dc=1.15 g/cm^3,λ(Moka)=0.71069 ,μ=7.67 cm^(-1), F(000)=648,T=296K,final R=0.060,Rw=0.073 for 1909 observed reflections with Ⅰ≥3σ(Ⅰ).The complex adopts a square planar geometry as its coordination unit,the mean Ni-S and Ni-P distances are 2.216 and 2.221 ,respectivety.
文摘In the paper, dicalcium silicate (C2S) was modified to obtain higher performance, and the solutionizing pattern of BaSO4 in cement clinker was analyzed theoretically. According to experimental results, solutionizing of BaSO4in cement clinker improved crystal plane distance of C2S as well as the relations of coordination. The performance tests show that the strength of C2S modified by BaSO4 changes and the reactivity of C2S increases significantly.
文摘(CH_3C_5H_4)Zr(S_2CNBz_2)_3, Mr=987.55, space group P1, a=13.002(4), b=13.659(3), c=29.685(8); α=100.72(2)~o,β=97.23(2)~o, γ=105.36(2)~o; V=4909(2)~3, Z=4, Dc=1.34gcm^(-3), Mo-K(λ=0.71073A) radiation, μ=5.0cm^(-1), R=0.069, Rw=0.078 for 6100 reflections. The title complex has pentagonal bipyramid configuration in which the zirconium atom is coordinated by one CH_3C_5H_4 group and three bidentate dibenzyldithiocarbamate ligands.
文摘Cp;ZrCl(S;CNBz;) is a five-coordinate bent zirconocene in which the dibenzyldithiocarbamate is a bidentate ligand (Zr-Cl 2.549(1)A; Zr-C 2.489-2.533; Zr-S 2.667(1), 2.734(1); Zr-Cl-S1 137.6(1);; Zr-Cl-S2 73.3(1);).
文摘The compound phenol,2-[4(S)-4,5-dihydro-4-phenyl-2-ozazolinyl(1,C15H13NO2) was synthesized with a simple,one step method free of water and air.It was obtained in a moderate yield from the reaction of 2-hydroxybenzonitrile with optically active amino alcohol in chloroben-zene under dry,anaerobic conditions.It belongs to the orthorhombic system,space group P212121 with a = 5.786(5),b = 10.730(5),c = 19.722(5),C15H13NO2,Mr = 239.26,V = 1224.4(12)3,Z = 4 and Dc = 1.298 mg/m3.The final R = 0.0324 for 1627 observed reflections with Ⅰ 〉 2σ(Ⅰ) and Rw = 0.0826 for all data.The structure of compound 1 was determined by X-ray diffraction,NMR and HRMS.