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Search Results: 1 - 10 of 93176 matches for " Xu Jun-Hua "
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Mechanical Properties and Tribological Performance of TiN/VCN Multilayers
CAO Jun, XU Jun-Hua, YU Li-Hua
无机材料学报 , 2013, DOI: 10.3724/sp.j.1077.2013.12196
Abstract: Monolithic TiN, VCN films and TiN/VCN nano-multilayer films with different modulation periods were prepared by magnetron sputtering. Microstructures, mechanical properties and friction properties at room and high temperature of these films were investigated by X-ray diffraction (XRD), nano-indentation, and CSM high temperature ball-on-disc tribometer. The results show that the TiN/VCN multilayer films are mainly nanocrystalline with δ-NaCl fcc structure. Maximum hardness of TiN/VCN multilayer films is 28.71 GPa, about 23% higher than the value calculated by the rule of mixtures. Based on these data, a mechanism of the superhardness in this system is proposed. Friction coefficients of TiN/VCN multilayers are similar to that of TiN films at room temperature, but lower than that of TiN films when testing temperature is increased to 700 Wear rates of TiN/VCN multilayers at room and high temperature decrease about 3×10-14 m3/(N·m) comparing to that of single layer film. The lubrication mechanism of Magnéli phase (V2O5) is discussed in terms of crystal chemistry and thermal measurement methods. In conclusion, compared to TiN films, the friction and wear properties of TiN/VCN multilayer films are greatly improved.
Influence of Ag content on the microstructure, mechanical, and tribological properties of TaVN–Ag films
Tong Chen,Li-hua Yu,Jun-hua Xu
- , 2018, DOI: https://doi.org/10.1007/s12613-018-1553-3
Abstract: A series of TaVN–Ag nanocomposite films were deposited using a radio-frequency magnetron sputtering system. The microstructure, mechanical properties, and tribological performance of the films were investigated. The results showed that TaVN–Ag films were composed of face-centered cubic (fcc) TaVN and fcc-Ag. With increasing Ag content, the hardness of TaVN–Ag composite films first increased and then decreased rapidly. The maximum hardness value was 31.4 GPa. At room temperature, the coefficient of friction (COF) of TaVN–Ag films decreased from 0.76 to 0.60 with increasing Ag content from 0 to 7.93at%. For the TaVN–Ag films with 7.93at% Ag, COF first increased and then decreased rapidly from 0.60 at 25°C to 0.35 at 600°C, whereas the wear rate of the film increased continuously from 3.91 × 10?7 to 19.1 × 10?7 mm3/(N·mm). The COF of the TaVN–Ag film with 7.93at% Ag was lower than that of the TaVN film, and their wear rates showed opposite trends with increasing temperature.
Bis(μ-4-chloro-2-oxidobenzoato)bis[(1,10-phenanthroline)copper(II)] dihydrate
Jing-Jing Nie,Jun-Hua Li,Duan-Jun Xu
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810008354
Abstract: The structure of the the title compound, [Cu2(C7H3ClO3)2(C12H8N2)2]·2H2O, consists of a dimeric unit involving a planar Cu2O2 group arranged around an inversion center. The coordination sphere of the CuII atom can be described as an elongated distorted square pyramid where the basal plane is formed by the two N atoms of the 1,10-phenanthroline molecule and the two O atoms of the hydroxychlorobenzoate (hcbe) anion. The long apical Cu—O distance of 2.569 (2) involves the O atom of a symmetry-related hcbe anion, building up the dinuclear unit. Each dinuclear unit is connected through O—H...O hydrogen bonds involving two water molecules, resulting in an R42(8) graph-set motif and building up an infinite chain parallel to (10overline{1}). C—H...O interactions further stabilize the chain.
Bis(3-hydroxypyridinium) fumarate
Lan Shen,Jun-Hua Li,Jing-Jing Nie,Duan-Jun Xu
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809023800
Abstract: The crystal structure of the title compound, 2C5H6NO2+·C4H2O42 , consists of 3-hydroxypyridinium cations and fumarate dianions. The dianion is located on an inversion center and the cation is linked to it by O—H...O and N—H...O hydrogen bonds. The cation is twisted with respect to the anion by 24.83 (5)°.
Hexakis(1H-imidazole-κN3)cobalt(II) triaquatris(1H-imidazole-κN3)cobalt(II) bis(naphthalene-1,4-dicarboxylate)
Jing-Jing Nie,Jun-Hua Li,Duan-Jun Xu
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809023794
Abstract: The asymmetric unit of the title compound, [Co(C3H4N2)6][Co(C3H4N2)3(H2O)3](C12H6O4)2, contains two halves of crystallographically independent CoII complex cations, each assuming a distorted octahedral geometry, and one uncoordinated naphthalene-1,4-dicarboxylate dianion. One CoII cation is located on an inversion center and is coordinated by six imidazole molecules, while the other CoII cation is located on a twofold rotation axis and is coordinated by three water and three imidazole molecules. The uncoordinated naphthalene-1,4-dicarboxylate dianion links both CoII complex cations via O—H...O and N—H...O hydrogen bonding. One imidazole ligand is equally disordered over two sites about a twofold rotation axis, while the coordinated N atom of the imidazole is located on the twofold rotation axis. One water O atom has site symmetry 2.
Hexakis(1H-imidazole-κN3)nickel(II) triaquatris(1H-imidazole-κN3)nickel(II) bis(naphthalene-1,4-dicarboxylate)
Jun-Hua Li,Jing-Jing Nie,Duan-Jun Xu
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808024215
Abstract: The crystal structure of the title compound, [Ni(C3H4N2)6][Ni(C3H4N2)3(H2O)3](C12H6O4)2, contains uncoordinated naphthalenedicarboxylate dianions and two kinds of NiII complex cations, both assuming distorted octahedral geometries. One NiII ion is located on an inversion center and is coordinated by six imidazole molecules, while the other NiII ion is located on a twofold rotation axis and is coordinated by three water molecules and three imidazole molecules in a mer-NiN3O3 arrangement. The naphthalenedicarboxylate dianion links both NiII complex cations via O—H...O and N—H...O hydrogen bonding, but no π–π stacking is observed between aromatic rings in the crystal structure. One imidazole ligand is equally disordered over two sites about a twofold rotation axis; one N atom and one water O atom have site symmetry 2.
Bis(3-hydroxypyridine-κN)bis(3-nitrobenzoato-κO)zinc(II)
Jun-Hua Li,Jing-Jing Nie,Duan-Jun Xu
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809027147
Abstract: The title complex, [Zn(C7H4NO4)2(C5H5NO)2], has site symmetry 2. The ZnII ion is located on a crystallographic twofold rotation axis and assumes a distorted tetrahedral ZnN2O2 coordination geometry. Molecules are linked by an intermolecular O—H...O hydrogen bond and π–π stacking interactions between pyridine rings [centroid–centroid speparation 3.594 (1) ].
Hexakis(1H-imidazole-κN3)manganese(II) triaquatris(1H-imidazole-κN3)manganese(II) bis(naphthalene-1,4-dicarboxylate)
Jun-Hua Li,Jing-Jing Nie,Duan-Jun Xu
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808011677
Abstract: In the crystal structure of the title compound, [Mn(C3H4N2)6][Mn(C3H4N2)3(H2O)3](C12H6O4)2, there are uncoordinated naphthalenedicarboxylate dianions and two kinds of MnII complex cations, both assuming a distorted octahedral geometry. One MnII cation is located on an inversion center and is coordinated by six imidazole molecules, while the other MnII cation is located on a twofold rotation axis and is coordinated by three water molecules and three imidazole units. The naphthalenedicarboxylate dianions are linked to both MnII complex cations via O—H...O and N—H...O hydrogen bonding, but no π–π stacking is observed between aromatic rings in the crystal structure.
Aqua(3-hydroxybenzoato-κO)bis(1,10-phenanthroline-κ2N,N′)cobalt(II) 3-hydroxybenzoate pentahydrate
Jun-Hua Li,Jing-Jing Nie,Jian-Rong Su,Duan-Jun Xu
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808001815
Abstract: The crystal structure of the title compound, [Co(C7H5O3)(C12H8N2)2(H2O)](C7H5O3)·5H2O, consists of CoII complex cations, uncoordinated hydroxybenzoate anions and uncoordinated water molecules. The CoII ion is coordinated by two phenanthroline ligands, a water molecule and a 3-hydroxybenzoate anion, and displays a distorted octahedral geometry. π–π stacking is observed between parallel phenanthroline ligands, the face-to-face separations being 3.454 (19) and 3.435 (7) . An extensive hydrogen-bonding network helps to stabilize the crystal structure. The hydroxybenzoate ligand is disordered over two positions, with site occupancy factors 0.6 and 0.4. One solvent water molecule is also disordered over two positions, with site occupancy factors 0.6 and 0.4.
catena-Poly[[[aquabis(1H-imidazole-κN3)copper(II)]-μ-naphthalene-1,4-dicarboxylato-κ2O1:O4] dihydrate]
Jun-Hua Li,Jing-Jing Nie,Duan-Jun Xu
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808018515
Abstract: In the title compound, {[Cu(C12H6O4)(C3H4N2)2(H2O)]·2H2O}n, the CuII cation is coordinated by two naphthalene-1,4-dicarboxylate (naph) dianions, two imidazole molecules and one water molecule in a distorted square-pyramidal geometry. The Cu—O bond distance in the apical direction is 0.509 (3) longer than the mean Cu—O bond distance in the basal plane. The naph dianion bridges two CuII cations, forming a one-dimensional polymeric chain. The coordinated water molecule is hydrogen-bonded to the carboxylate groups and imidazole ligands of adjacent polymeric chains, forming a three-dimensional supramolecular structure. No π–π stacking is observed in the crystal structure. One solvent water molecule is disordered equally over two positions.
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