The electronic structures of pure V, Nb and Ta metals with bcc structure were determined by one atom (OA) theory. According to the electronic structures of these metals, their potential curves, cohesive energies, latt...The electronic structures of pure V, Nb and Ta metals with bcc structure were determined by one atom (OA) theory. According to the electronic structures of these metals, their potential curves, cohesive energies, lattice parameters, elasticity and the dependence of linear thermal expansion coefficients on temperature were calculated. The electronic structures and characteristic properties of these metals with fcc and hcp structures and liquid states were studied.展开更多
The Panzhihua intrusion in southwest China is part of the Emeishan large igneous province and host of a large Fe-Ti-V ore deposit.In previous interpretations it was considered to be a layered,differentiated sill with ...The Panzhihua intrusion in southwest China is part of the Emeishan large igneous province and host of a large Fe-Ti-V ore deposit.In previous interpretations it was considered to be a layered,differentiated sill with the ore deposits at its base.New structural and petrological data suggest instead that the intrusion has an open S-shape,with two near-concordant segments joined by a discordant dyke-like segment. During emplacement of the main intrusion,multiple generations of mafic dykes invaded carbonate wall rocks,producing a large contact aureole.In the central segment,magmatic layering is oriented oblique to the walls of the intrusion.This layering cannot have formed by crystal settling or in-situ growth on the floor of the intrusion;instead we propose that it resulted from inward solidification of multiple,individually operating,convection cells.Ore formation was triggered by interaction of magma with carbonate wall rocks.展开更多
Chao Lake is a Geoheritage site on the active Tan-Lu Fault between the Yangtze craton,the North China craton,and the Dabie orogenic belt in the southeast.This segment of the fault is not well constrained at depth part...Chao Lake is a Geoheritage site on the active Tan-Lu Fault between the Yangtze craton,the North China craton,and the Dabie orogenic belt in the southeast.This segment of the fault is not well constrained at depth partly due to the overprinting of the fault zone by intrusive materials and its relatively low seismic activity and sparse seismic station coverage.This study took advantage of a dense seismic array deployed around Chao Lake to delineate the P-wave velocity variations in the crust and uppermost mantle using teleseismic earthquake arrival time tomography.The station-pair double-difference with waveform crosscorrelation technique was employed.We used a multiscale resolution 3-D initial model derived from the combination of highresolution 3-D v S models within the region of interest to account for the lateral heterogeneity in the upper crust.The results revealed that the velocity of the upper crust is segmented with structures trending in the direction of the strike of the fault.Sedimentary basins are delineated on both sides of the fault with slow velocities,while the fault zone is characterized by high velocity in the crust and uppermost mantle.The high-velocity structure in the fault zone shows characteristics of magma intrusion that may be connected to the Mesozoic magmatism in and around the Middle and Lower Yangtze River Metallogenic Belt(MLYMB),implying that the Tan-Lu fault might have formed a channel for magma intrusion.Magmatic material in Chao Lake is likely connected to the partial melting,assimilation,storage,and homogenization of the uppermost mantle and the lower crustal rocks.The intrusions,however,seem to have suffered severe regional extension along the Tan-Lu fault driven by the eastward Paleo-Pacific plate subduction,thereby losing its deep trail due to extensional erosion.展开更多
The new oxovanadium(V)complex,[PyH][VO2(L)]1(salicyladehyde 5-bromo salicyloylhydrazone is abbreviated as H2L;Hpy is protonated pyridine)was obtained from a refluxed solution of VOSO4 and H2L in acetonitrile-methanol-...The new oxovanadium(V)complex,[PyH][VO2(L)]1(salicyladehyde 5-bromo salicyloylhydrazone is abbreviated as H2L;Hpy is protonated pyridine)was obtained from a refluxed solution of VOSO4 and H2L in acetonitrile-methanol-pyridine.Similarly,another new complex,[VO(L)(OCH3)]2 was synthesized by refluxing VOSO4 and H2L in methanol-pyridine.Crystal data for 1:C19H15N3O5BrV,Mr=496.2,monoclinic,P21/n,a=7.1885(3),b=9.2718(3),c=28.803(1)A,β=96.185(1)°,Z=4and V=1908.6(1)A^3;for 2:C15H12N2O5BrV,Mr=431.1,monoclinic ,P21/n,a=12.202(2),b=8.045(2),c=16.604(3)A,β=101.29(3)°,Z=4 and V=1598.4(2)A^3.The structures of 1 and 2 have been determined by X-ray analyses and reveal that the coordination environments of V atoms in both complexes are of square-based pyramid.Three of the four based donor atoms are from the tridentate“ONO”donor ligand while the fourth is one terminal oxygen atom with the V(1)-O(3)distance 1.646(4)Afor 1 and one-OCH3 group with the V(1)-O(3) distance 1.753(3)Afor 2.The V(1)-O(4) terminals occupy the axial sites in both cases.The complexes are also characterized by IR and ^1HNMR spectroscopies.展开更多
The crystal structure, band structure, density of states, Mulliken charge, bond population and optical properties for LiBi_（1-x）M_xO_3（M=V, Nb, and Ta） were investigated using hybrid density functional theory. It ...The crystal structure, band structure, density of states, Mulliken charge, bond population and optical properties for LiBi_（1-x）M_xO_3（M=V, Nb, and Ta） were investigated using hybrid density functional theory. It was found that LiBiO_3 doped with V, Nb, and Ta presented distinctly stronger covalent interactions in M-O（M=V, Nb, and Ta） than Bi-O, thus resulting in mild distortion of the structure and facilitating the separation of photogenerated carriers. Furthermore, the hybridizations of Bi-6s, M-d（M=V, Nb, and Ta） and O-2p widened the valence and conduction bands, which promoted transmission of photogenerated carriers in the band edge and thus caused better photocatalytic performance.展开更多
The novel complex of Mn(V): Mn·3/2(μ -DHBQ)·4H2O·2Cl (where, H2DHBQ =2,5-dihydroxyl- 1,4-benzoquinone) was synthesized and its crystal structure has been determined by X-ray diffraction. The complex be...The novel complex of Mn(V): Mn·3/2(μ -DHBQ)·4H2O·2Cl (where, H2DHBQ =2,5-dihydroxyl- 1,4-benzoquinone) was synthesized and its crystal structure has been determined by X-ray diffraction. The complex belongs to trigonal system with space group P3(# 147), a= 1 .415(2)nm, c=0.6552(4) nm, V=1 .1371(7) nm-3, Z=2, Dx=1.183 g/cm3, μ=7.37 cm-1, F(000)=408.00,R=0.041, Rw=0.046.展开更多
A new molybdenum phosphate [Zn（Mo^v6P4O31H10）2（C4H144N3）2].2C4H13N3.8H2O 1 （C4H13N3 = diethylenetriamine） has been synthesized under hydrothermal condition. Single-crystal X-ray diffraction reveals that compound...A new molybdenum phosphate [Zn（Mo^v6P4O31H10）2（C4H144N3）2].2C4H13N3.8H2O 1 （C4H13N3 = diethylenetriamine） has been synthesized under hydrothermal condition. Single-crystal X-ray diffraction reveals that compound 1 crystallizes in the monoclinic, space group P21/n, a = 13.1679（3）, b = 22.1240（6）, c = 13.6146（3） A, β= 103.4847（7）°, V = 3856.95（16） A^3, C16H90N12O70P8ZnMo12, Mr = 3035.41, Z = 2, Dc = 2.614 g/cm^3, μ = 2.483 mm^-1, F（000） = 2968, S = 1.014, the final R = 0.0196 and wR = 0.0506 for 7486 observed reflections （1 〉 2σ（I））. Compound 1 consists of two identical rings of six edge-sharing MoOt, octahedra interconnected by one ZnO6 octahedron, whereas the PO4 tetrahedra which share their apices with the MoO6, octahedra are only located on one side of each Mo6, ring. The 2-charge of polyanion [Zn（Mo^v6P4O31H10）2]^2- unit is compensated in the crystal by two mono-protonated diethylenetriamines （C4H14N3）^＋. By hydrogen bonding interactions the polyanion of compound 1 is interconnected to form pseudo threedimensional molybdophosphate. Other characterizations by elemental analyses, IR spectrum and fluorescent spectrum are also described.展开更多
A novel vanadium（V） oxoperoxo complex [VOO2（APTCH）（CH3OH）] （HAPTCH = 2-acetylpyridine thiophene-2-carboxylic hydrazone） has been synthesized and characterized by IR, TGA and X-ray single-crystal structure dete...A novel vanadium（V） oxoperoxo complex [VOO2（APTCH）（CH3OH）] （HAPTCH = 2-acetylpyridine thiophene-2-carboxylic hydrazone） has been synthesized and characterized by IR, TGA and X-ray single-crystal structure determination. The complex crystallizes in the monoclinic system, space group P21/c with a = 11.232（2）, b = 10.762（2）, c = 112.613（3）, β = 99.44（3）°, V = 1504.1（5）3, Dc = 1.657 g·cm-3, Z = 4, F（000） = 768, μ = 0.827 mm-1, the final R = 0.0392 and wR = 0.1073 for 2266 observed reflections with I 〉 2σ（I）. Single-crystal X-ray diffraction studies reveal that the vanadium（V） is coordinated by a tridentate ligand, methanol molecule and peroxo group to form a pentagonal-bipyramidal geometry. The crystal structure is stabilized by intermolecular hydrogen bonds of O-H···N and C-H···O.展开更多
The composition and structure of Ti 6Al 4V alloy plasma based ion implanted with nitrogen was investigated.The nitrogen depth distribution shows more antiballistic with distribution peak heightened with increased i...The composition and structure of Ti 6Al 4V alloy plasma based ion implanted with nitrogen was investigated.The nitrogen depth distribution shows more antiballistic with distribution peak heightened with increased implantation time(dose),and more like a parabola at the low implantation pulse voltage.When implantation pulse voltage is increased,the implantation depth increased with the nitrogen distribution peak being deepened,widened and lowered somewhat.TiN,TiN+Ti 2N,or Ti 2N second phases were formed in the implanted layer.The relative percentage of nitrogen content in the form of TiN increases when going deeper into the implanted(TiN formed) layer.The increase of implantation pulse width and/or time is favourable for the formation of TiN rather than Ti 2N.It is unfavourable for formation of any nitrides when implantation pulse voltage is decreased to 30kV or less.Tiny crystalline particles (made mainly of Ti 2N and a smaller percentage of TiO 2 phases) of regular shapes such as triangle and tetragon, etc .(about 20 nm) are found distrbuted dispersively in the near surface region of samples implanted at the high implantation pulse voltage (75kV).展开更多
Using a linked-parameter technique of level-fitting calculations in a multi configuration basis, a parametric analysis of fine structure (fs) for even-parity levels of V II, involving six configurations, has been perf...Using a linked-parameter technique of level-fitting calculations in a multi configuration basis, a parametric analysis of fine structure (fs) for even-parity levels of V II, involving six configurations, has been performed. This led us to exchange the assignments of two triplets, 3d3(2F)4s c 3F and 3d4 d 3F, reported in earlier analyses as being located at 30,300 cm-1 and 30,600 cm-1, respectively. This is confirmed by experimental hyperfine structure (hfs) A constants, used as fingerprints. Moreover, the current singlet 3d24s2 1D2 position is likely too high. The fs parameters, magnetic Landé g-factors, and the percentage of leading eigenvectors of levels are calculated. We present also predicted singlet, triplet and quintet positions for missing experimental levels up to 100,000 cm-1. The single-electron hfs parameters are determined in their entirety for 51V II for the model space (3d + 4s)4 with good accuracy. For the model space (3d + 4s)4 of 51V II the single-electron hfs parameters are computed;furthermore, our achieved theoretical evaluations of the single-electron hfs parameters, thanks to the use of ab initio calculations, reinforce the validity of these hfs parameter values, deduced from experimental data.展开更多
The 3d34p, 3d35p and 3d24s4p odd configurations of the V II spectrum have been reanalysed and three 3d24s4p triplets are assigned higher energies than previously proposed. We have determined the fine structure paramet...The 3d34p, 3d35p and 3d24s4p odd configurations of the V II spectrum have been reanalysed and three 3d24s4p triplets are assigned higher energies than previously proposed. We have determined the fine structure parameters, the largest and next largest eigenvector percentages of levels, their calculated Landé gJ-factors and predicted positions for missing experimental levels up to 100,000 cm-1 for the 3d24s4p configuration. Furthermore for the first time a hyperfine structure (HFS) parametric treatment, involving levels of these two configurations has been carried out. The deduced single-electron HFS parameter values are successfully checked with those obtained by means of ab initio calculations.展开更多
Superplastic forming and diffusion bonding (SPF/DB) is a well-established process for the manufacture of components almost exclusively from Ti-6AI-4V sheet material. The sandwich structure of Ti-6AI-4V alloy is invest...Superplastic forming and diffusion bonding (SPF/DB) is a well-established process for the manufacture of components almost exclusively from Ti-6AI-4V sheet material. The sandwich structure of Ti-6AI-4V alloy is investigated. The effects of the microstructure on the SPF/DB process were discussed. The microstructure at the interfaces and the distribution of thickness were researched.展开更多
The nitrogen-doped porous TiO2 layer on Ti6Al4V substrate was fabricated by plasma-based ion implantation of He, O and N. In order to increase the photodegradation efficiency of TiO2 layer, two methods were used in th...The nitrogen-doped porous TiO2 layer on Ti6Al4V substrate was fabricated by plasma-based ion implantation of He, O and N. In order to increase the photodegradation efficiency of TiO2 layer, two methods were used in the process by forming mesopores to increase the specific surface area and by nitrogen doping to increase visible light absorption. Importantly, TiO2 formation, porosity architectures and nitrogen doping can be performed by implantation of He, O and N in one step. After implantation, annealing at 650 ℃ leads to a mixing phase of anatase with a little rutile in the implanted layer. By removing the near surface compact layer using argon ion sputtering, the meso-porous structure was exposed on surfaces. Nitrogen doping enlarges the photo-response region of visible light. Moreover, the nitrogen dose of 8×1015 ion/cm2 induces a stronger visible light absorption. The photodegradation of rhodamine B solution with visible light sources indicates that the mesopores on surfaces and nitrogen doping contribute to an apparent increase of photocatalysis efficiency.展开更多
The complex K_3H_4GeW_9V_3O_(40)·8H_2O crystallized in a monocliinie system with space group P2, Mr=2784.67, a=11.099(3), b=16.452(4), c=13.534(4) , β=108.14(2)°, Z=2,V=2348.49 ~3, F(000):2456, μ=239.7cm^(...The complex K_3H_4GeW_9V_3O_(40)·8H_2O crystallized in a monocliinie system with space group P2, Mr=2784.67, a=11.099(3), b=16.452(4), c=13.534(4) , β=108.14(2)°, Z=2,V=2348.49 ~3, F(000):2456, μ=239.7cm^(-1), De=3.932 g/cm^3. The final R=0.083 for 4528 non-zero reflexions. The structure of anions GeW_9V_3O_(40)~and GeW_9O_(34)~belongs to A-type.展开更多
The magnetic structure of the spin-chain antiferromagnet SrCo2 V208 is determined by single-crystal neutron diffraction experiment. The system undergoes a long-range magnetic order below the critical temperature TN=4....The magnetic structure of the spin-chain antiferromagnet SrCo2 V208 is determined by single-crystal neutron diffraction experiment. The system undergoes a long-range magnetic order below the critical temperature TN=4.96 K. The moment of 2.16#B per Co at 1.6K in the screw chain running along the c axis Mternates in the c axis. The moments of neighboring screw chains are arranged antiferromagnetically along one in-plane axis and ferromagnetieally Monk the other in-plane axis. This magnetic configuration breaks the four-fold symmetry of the tetragonM crystal structure and leads to two equally populated magnetic twins with the antiferromagnetic vector in the a or b axis. The very similar magnetic state to the isostructural BaCo2 V~ 08 warrants SrCo2 V2 08 as another interesting half-integer spin-chain antiferromagnet for investigation on quantum antiferromagnetism.展开更多
文摘The electronic structures of pure V, Nb and Ta metals with bcc structure were determined by one atom (OA) theory. According to the electronic structures of these metals, their potential curves, cohesive energies, lattice parameters, elasticity and the dependence of linear thermal expansion coefficients on temperature were calculated. The electronic structures and characteristic properties of these metals with fcc and hcp structures and liquid states were studied.
基金supported by a Famous overseas professor project MS2011ZGDZ[BJ]019 through China University of Geosciences (Beijing)and by the USA NSF "Continental Geodynamics" programGeologists from the Panzhihua mining company are thanked for their logistic support
文摘The Panzhihua intrusion in southwest China is part of the Emeishan large igneous province and host of a large Fe-Ti-V ore deposit.In previous interpretations it was considered to be a layered,differentiated sill with the ore deposits at its base.New structural and petrological data suggest instead that the intrusion has an open S-shape,with two near-concordant segments joined by a discordant dyke-like segment. During emplacement of the main intrusion,multiple generations of mafic dykes invaded carbonate wall rocks,producing a large contact aureole.In the central segment,magmatic layering is oriented oblique to the walls of the intrusion.This layering cannot have formed by crystal settling or in-situ growth on the floor of the intrusion;instead we propose that it resulted from inward solidification of multiple,individually operating,convection cells.Ore formation was triggered by interaction of magma with carbonate wall rocks.
基金funded by China’s National Natural Science Foundation (Nos. 42125401 and 42004031)the Hefei Key Technology Research and Development Project (No. J2020J06)
文摘Chao Lake is a Geoheritage site on the active Tan-Lu Fault between the Yangtze craton,the North China craton,and the Dabie orogenic belt in the southeast.This segment of the fault is not well constrained at depth partly due to the overprinting of the fault zone by intrusive materials and its relatively low seismic activity and sparse seismic station coverage.This study took advantage of a dense seismic array deployed around Chao Lake to delineate the P-wave velocity variations in the crust and uppermost mantle using teleseismic earthquake arrival time tomography.The station-pair double-difference with waveform crosscorrelation technique was employed.We used a multiscale resolution 3-D initial model derived from the combination of highresolution 3-D v S models within the region of interest to account for the lateral heterogeneity in the upper crust.The results revealed that the velocity of the upper crust is segmented with structures trending in the direction of the strike of the fault.Sedimentary basins are delineated on both sides of the fault with slow velocities,while the fault zone is characterized by high velocity in the crust and uppermost mantle.The high-velocity structure in the fault zone shows characteristics of magma intrusion that may be connected to the Mesozoic magmatism in and around the Middle and Lower Yangtze River Metallogenic Belt(MLYMB),implying that the Tan-Lu fault might have formed a channel for magma intrusion.Magmatic material in Chao Lake is likely connected to the partial melting,assimilation,storage,and homogenization of the uppermost mantle and the lower crustal rocks.The intrusions,however,seem to have suffered severe regional extension along the Tan-Lu fault driven by the eastward Paleo-Pacific plate subduction,thereby losing its deep trail due to extensional erosion.
基金The work was supported by the Chinese Academy of Sciences, the National Natural Science Foundation of China(20073048)the NSF of Fujian province for financial support
文摘The new oxovanadium(V)complex,[PyH][VO2(L)]1(salicyladehyde 5-bromo salicyloylhydrazone is abbreviated as H2L;Hpy is protonated pyridine)was obtained from a refluxed solution of VOSO4 and H2L in acetonitrile-methanol-pyridine.Similarly,another new complex,[VO(L)(OCH3)]2 was synthesized by refluxing VOSO4 and H2L in methanol-pyridine.Crystal data for 1:C19H15N3O5BrV,Mr=496.2,monoclinic,P21/n,a=7.1885(3),b=9.2718(3),c=28.803(1)A,β=96.185(1)°,Z=4and V=1908.6(1)A^3;for 2:C15H12N2O5BrV,Mr=431.1,monoclinic ,P21/n,a=12.202(2),b=8.045(2),c=16.604(3)A,β=101.29(3)°,Z=4 and V=1598.4(2)A^3.The structures of 1 and 2 have been determined by X-ray analyses and reveal that the coordination environments of V atoms in both complexes are of square-based pyramid.Three of the four based donor atoms are from the tridentate“ONO”donor ligand while the fourth is one terminal oxygen atom with the V(1)-O(3)distance 1.646(4)Afor 1 and one-OCH3 group with the V(1)-O(3) distance 1.753(3)Afor 2.The V(1)-O(4) terminals occupy the axial sites in both cases.The complexes are also characterized by IR and ^1HNMR spectroscopies.
基金the National Natural Science Foundation of China(No.61275108)the Natural Science Foundation of Zhejiang province in China(Nos.LY15F050009 and Y111049)
文摘The crystal structure, band structure, density of states, Mulliken charge, bond population and optical properties for LiBi_（1-x）M_xO_3（M=V, Nb, and Ta） were investigated using hybrid density functional theory. It was found that LiBiO_3 doped with V, Nb, and Ta presented distinctly stronger covalent interactions in M-O（M=V, Nb, and Ta） than Bi-O, thus resulting in mild distortion of the structure and facilitating the separation of photogenerated carriers. Furthermore, the hybridizations of Bi-6s, M-d（M=V, Nb, and Ta） and O-2p widened the valence and conduction bands, which promoted transmission of photogenerated carriers in the band edge and thus caused better photocatalytic performance.
文摘The novel complex of Mn(V): Mn·3/2(μ -DHBQ)·4H2O·2Cl (where, H2DHBQ =2,5-dihydroxyl- 1,4-benzoquinone) was synthesized and its crystal structure has been determined by X-ray diffraction. The complex belongs to trigonal system with space group P3(# 147), a= 1 .415(2)nm, c=0.6552(4) nm, V=1 .1371(7) nm-3, Z=2, Dx=1.183 g/cm3, μ=7.37 cm-1, F(000)=408.00,R=0.041, Rw=0.046.
基金Project supported by the Natural Science Foundation of Fujian Province (E0310016) and the Education Committee Foundation of Fujian Province (JB05309)
文摘A new molybdenum phosphate [Zn（Mo^v6P4O31H10）2（C4H144N3）2].2C4H13N3.8H2O 1 （C4H13N3 = diethylenetriamine） has been synthesized under hydrothermal condition. Single-crystal X-ray diffraction reveals that compound 1 crystallizes in the monoclinic, space group P21/n, a = 13.1679（3）, b = 22.1240（6）, c = 13.6146（3） A, β= 103.4847（7）°, V = 3856.95（16） A^3, C16H90N12O70P8ZnMo12, Mr = 3035.41, Z = 2, Dc = 2.614 g/cm^3, μ = 2.483 mm^-1, F（000） = 2968, S = 1.014, the final R = 0.0196 and wR = 0.0506 for 7486 observed reflections （1 〉 2σ（I））. Compound 1 consists of two identical rings of six edge-sharing MoOt, octahedra interconnected by one ZnO6 octahedron, whereas the PO4 tetrahedra which share their apices with the MoO6, octahedra are only located on one side of each Mo6, ring. The 2-charge of polyanion [Zn（Mo^v6P4O31H10）2]^2- unit is compensated in the crystal by two mono-protonated diethylenetriamines （C4H14N3）^＋. By hydrogen bonding interactions the polyanion of compound 1 is interconnected to form pseudo threedimensional molybdophosphate. Other characterizations by elemental analyses, IR spectrum and fluorescent spectrum are also described.
基金supported by the Scientific Research Common Program of Beijing Municipal Commission of Education, PRC (KM200910028011)
文摘A novel vanadium（V） oxoperoxo complex [VOO2（APTCH）（CH3OH）] （HAPTCH = 2-acetylpyridine thiophene-2-carboxylic hydrazone） has been synthesized and characterized by IR, TGA and X-ray single-crystal structure determination. The complex crystallizes in the monoclinic system, space group P21/c with a = 11.232（2）, b = 10.762（2）, c = 112.613（3）, β = 99.44（3）°, V = 1504.1（5）3, Dc = 1.657 g·cm-3, Z = 4, F（000） = 768, μ = 0.827 mm-1, the final R = 0.0392 and wR = 0.1073 for 2266 observed reflections with I 〉 2σ（I）. Single-crystal X-ray diffraction studies reveal that the vanadium（V） is coordinated by a tridentate ligand, methanol molecule and peroxo group to form a pentagonal-bipyramidal geometry. The crystal structure is stabilized by intermolecular hydrogen bonds of O-H···N and C-H···O.
文摘The composition and structure of Ti 6Al 4V alloy plasma based ion implanted with nitrogen was investigated.The nitrogen depth distribution shows more antiballistic with distribution peak heightened with increased implantation time(dose),and more like a parabola at the low implantation pulse voltage.When implantation pulse voltage is increased,the implantation depth increased with the nitrogen distribution peak being deepened,widened and lowered somewhat.TiN,TiN+Ti 2N,or Ti 2N second phases were formed in the implanted layer.The relative percentage of nitrogen content in the form of TiN increases when going deeper into the implanted(TiN formed) layer.The increase of implantation pulse width and/or time is favourable for the formation of TiN rather than Ti 2N.It is unfavourable for formation of any nitrides when implantation pulse voltage is decreased to 30kV or less.Tiny crystalline particles (made mainly of Ti 2N and a smaller percentage of TiO 2 phases) of regular shapes such as triangle and tetragon, etc .(about 20 nm) are found distrbuted dispersively in the near surface region of samples implanted at the high implantation pulse voltage (75kV).
文摘Using a linked-parameter technique of level-fitting calculations in a multi configuration basis, a parametric analysis of fine structure (fs) for even-parity levels of V II, involving six configurations, has been performed. This led us to exchange the assignments of two triplets, 3d3(2F)4s c 3F and 3d4 d 3F, reported in earlier analyses as being located at 30,300 cm-1 and 30,600 cm-1, respectively. This is confirmed by experimental hyperfine structure (hfs) A constants, used as fingerprints. Moreover, the current singlet 3d24s2 1D2 position is likely too high. The fs parameters, magnetic Landé g-factors, and the percentage of leading eigenvectors of levels are calculated. We present also predicted singlet, triplet and quintet positions for missing experimental levels up to 100,000 cm-1. The single-electron hfs parameters are determined in their entirety for 51V II for the model space (3d + 4s)4 with good accuracy. For the model space (3d + 4s)4 of 51V II the single-electron hfs parameters are computed;furthermore, our achieved theoretical evaluations of the single-electron hfs parameters, thanks to the use of ab initio calculations, reinforce the validity of these hfs parameter values, deduced from experimental data.
文摘The 3d34p, 3d35p and 3d24s4p odd configurations of the V II spectrum have been reanalysed and three 3d24s4p triplets are assigned higher energies than previously proposed. We have determined the fine structure parameters, the largest and next largest eigenvector percentages of levels, their calculated Landé gJ-factors and predicted positions for missing experimental levels up to 100,000 cm-1 for the 3d24s4p configuration. Furthermore for the first time a hyperfine structure (HFS) parametric treatment, involving levels of these two configurations has been carried out. The deduced single-electron HFS parameter values are successfully checked with those obtained by means of ab initio calculations.
文摘Superplastic forming and diffusion bonding (SPF/DB) is a well-established process for the manufacture of components almost exclusively from Ti-6AI-4V sheet material. The sandwich structure of Ti-6AI-4V alloy is investigated. The effects of the microstructure on the SPF/DB process were discussed. The microstructure at the interfaces and the distribution of thickness were researched.
基金Project(20040213048) supported by the Specialized Research Fund for the Doctoral Program of Higher Education of ChinaProject(20090450737) supported by the China Postdoctoral Science Foundation
文摘The nitrogen-doped porous TiO2 layer on Ti6Al4V substrate was fabricated by plasma-based ion implantation of He, O and N. In order to increase the photodegradation efficiency of TiO2 layer, two methods were used in the process by forming mesopores to increase the specific surface area and by nitrogen doping to increase visible light absorption. Importantly, TiO2 formation, porosity architectures and nitrogen doping can be performed by implantation of He, O and N in one step. After implantation, annealing at 650 ℃ leads to a mixing phase of anatase with a little rutile in the implanted layer. By removing the near surface compact layer using argon ion sputtering, the meso-porous structure was exposed on surfaces. Nitrogen doping enlarges the photo-response region of visible light. Moreover, the nitrogen dose of 8×1015 ion/cm2 induces a stronger visible light absorption. The photodegradation of rhodamine B solution with visible light sources indicates that the mesopores on surfaces and nitrogen doping contribute to an apparent increase of photocatalysis efficiency.
文摘The complex K_3H_4GeW_9V_3O_(40)·8H_2O crystallized in a monocliinie system with space group P2, Mr=2784.67, a=11.099(3), b=16.452(4), c=13.534(4) , β=108.14(2)°, Z=2,V=2348.49 ~3, F(000):2456, μ=239.7cm^(-1), De=3.932 g/cm^3. The final R=0.083 for 4528 non-zero reflexions. The structure of anions GeW_9V_3O_(40)~and GeW_9O_(34)~belongs to A-type.
基金Supported by the National Basic Research Program of China under Grant Nos 2012CB921700 and 2011CBA00112the National Natural Science Foundation of China under Grant Nos 11034012 and 11190024
文摘The magnetic structure of the spin-chain antiferromagnet SrCo2 V208 is determined by single-crystal neutron diffraction experiment. The system undergoes a long-range magnetic order below the critical temperature TN=4.96 K. The moment of 2.16#B per Co at 1.6K in the screw chain running along the c axis Mternates in the c axis. The moments of neighboring screw chains are arranged antiferromagnetically along one in-plane axis and ferromagnetieally Monk the other in-plane axis. This magnetic configuration breaks the four-fold symmetry of the tetragonM crystal structure and leads to two equally populated magnetic twins with the antiferromagnetic vector in the a or b axis. The very similar magnetic state to the isostructural BaCo2 V~ 08 warrants SrCo2 V2 08 as another interesting half-integer spin-chain antiferromagnet for investigation on quantum antiferromagnetism.
