The aim of present work is to investigate the influencing factors on mechanical property stability of Cu-Mo-Ni alloyed austempered ductile iron （ADI）. The results show that after austenitized at 900℃ for 2 h follow...The aim of present work is to investigate the influencing factors on mechanical property stability of Cu-Mo-Ni alloyed austempered ductile iron （ADI）. The results show that after austenitized at 900℃ for 2 h followed by austempered at 370℃for another 2 h, the mechanical property of the alloyed ADI can reach the Germanite GGG-100 standard, i.e. σb≮1000 MPa,δ≮5%, at 95% confidence level. And the satisfactory mechanical properties were obtained when the alloyed ADI was austenitized at 850℃ to 1 000 ℃ for 1-4 h, and austempered at 355℃ to 400℃ for another 1 h to 4 h. The microstructures, including nodule number, white bright zone content （martensite-containing interdendritic segregation zone） and retained austenite content, can significantly influence the mechanical properties of the ADI. In order to obtain the good combinations of strength and ductility, the volume fraction of white bright zone should he less than 5%, and the retained austenite contents maintain hetween 30 % and 40%. The application of inoculation techniques to increase graphite nodule number can effectively reduce the white bright zone content in the structure.展开更多
For functional difference equations with unbounded delay,we characterized the existence of totally stable and asymptotically almost periodic solution by using stability properties of a bounded solution in a certain li...For functional difference equations with unbounded delay,we characterized the existence of totally stable and asymptotically almost periodic solution by using stability properties of a bounded solution in a certain limiting equation.展开更多
A new complex has been synthesized with o-methylbenzoyl-benzoic acid（HL） and 1,10-phenanthroline（phen） in the mixture of water and ethanol. It crystallizes in monoclinic, space group C2/c with a = 13.6328（18）, b...A new complex has been synthesized with o-methylbenzoyl-benzoic acid（HL） and 1,10-phenanthroline（phen） in the mixture of water and ethanol. It crystallizes in monoclinic, space group C2/c with a = 13.6328（18）, b = 17.7876（18）, c = 19.998（2）, β = 104.720（4）o, C54H48N4O11Zn, Mr = 994.33, V = 4690.2（9）3, Dc = 1.408 g/cm3, Z = 4, F（000） = 2072, μ（MoKα） = 0.59 mm-1, R = 0.0736 and wR = 0.2029. The crystal structure shows that the zinc ions are coordinated with two oxygen atoms from two HL molecules and four nitrogen atoms from two phen molecules, forming distorted octahedral coordination geometry. The fluorescent and thermal stability properties of the complex are studied. The result shows that it has one fluorescent emission band at around 412 nm. In addition, the complex is stable under 210 ℃.展开更多
This paper reports crystal structures, magnetic properties and thermal stability of TbCu7-type Sm（8.5）Fe（（85.8-x）Co（4.5）Zr（1.2）Nbx（x = 0-1.8） melt-spun compounds and their nitrides, investigated by means of...This paper reports crystal structures, magnetic properties and thermal stability of TbCu7-type Sm（8.5）Fe（（85.8-x）Co（4.5）Zr（1.2）Nbx（x = 0-1.8） melt-spun compounds and their nitrides, investigated by means of X-ray diffraction, vibrating sample magnetometer, flux meter and transmission electron microscope. It is found that the lattice parameter ratio c/a of TbCu7-type crystal structure increases with Nb substitution, which indicates that the Nb can increase the stability of the metastable phase in the Sm-Fe ribbons. Nb substitution impedes the formation of magnetic soft phase a-Fe in which reversed domains initially form during the magnetization reversal process. Meanwhile, Nb substitution refines grains and leads to homogeneous micro structure with augmented grain boundaries. Thus the exchange coupling pining field is enhanced and irreversible domain wall propagation gets suppressed. As a result, the magnetic properties are improved and the irreversible flux loss of magnets is notably decreased. A maximum value 771.7 kA/m of the intrinsic coercivity H（cj） is achieved in the 1.2 at% substituted samples.The irreversible flux loss for 2 h exposure at 120 ℃ declines from 8.26% for Nb-free magnets to 6.32% for magnets with 1.2 at% Nb substitution.展开更多
A new complex Cu2（o-C6H5COC6H5COO）4（C10H8N2）2（H2O）2 with 2-benzoylben- zoic acid and 2,2′-bipyridine as ligands has been synthesized in mixed methanol and water solvent. Crystal data are as follows： monoclinic...A new complex Cu2（o-C6H5COC6H5COO）4（C10H8N2）2（H2O）2 with 2-benzoylben- zoic acid and 2,2′-bipyridine as ligands has been synthesized in mixed methanol and water solvent. Crystal data are as follows： monoclinic, space group Co, a = 14.0133（14）, b = 16.0409（16）, c = 30.372（3） A, β = 100.8950（10）°, V = 6704.1（12） A3, Dc = 1.364 g/cm3, Z = 8,μ（MoKa） = 0.704 mml, F（000） = 2840, the final R= 0.0552 and wR = 0.1431. In the crystal structure, the whole molecule consists of two copper ions, four 2-benzoylbenzoic acid molecules, two 2,2′-bipyridine molecules and two water molecules. Each central copper ion is coordinated with two nitrogen atoms from one 2,2′-bipyridine molecule and three oxygen atoms from two 2-benzoylbenzoic acids and one water molecule, respectively, giving a distorted tetragonal pyramidal geometry. Thermal stability properties of the complex were investigated.展开更多
A new dinuclear copper（II） complex [Cu2（L）2（phen）2]·5H2O （1） with bicycle[2.2.1 ]hept- 2-en-5, 6-dicarboxylic acid （H2L） and 1,10-phenanthroline （phen） as ligands has been synthesized in the mixed sol...A new dinuclear copper（II） complex [Cu2（L）2（phen）2]·5H2O （1） with bicycle[2.2.1 ]hept- 2-en-5, 6-dicarboxylic acid （H2L） and 1,10-phenanthroline （phen） as ligands has been synthesized in the mixed solvents of ethanol and water. It crystallizes in the monoclinic space group P21/c, with a = 17.925（4）, b = 19.908（4）, c = 11.235（2） A, β = 97.65（3）°, V= 3973.4（14） A3, Dc = 1.552 g/cm^3, Z = 8, F（000） = 1910, the final GOOF = 1.056, R= 0.0519 and wR= 0.1293. The crystal structure shows that the whole molecule consists of two independent dinuclear units, in which two copper ions are bridged by twoμ2-η1 ：η0-3-carboxylate groups of L^2- anions. The fluorescence and thermal stability properties of 1 were studied. The results show that 1 has an intense fluorescent emission at around 381 rim. The TG analysis shows that I is stable below 143 ℃.展开更多
In open-pit mines,pit slope as one of the important parameters affects the mine economy and total minable reserve,and it is also affected by different uncertainties which arising from many sources.One of the most crit...In open-pit mines,pit slope as one of the important parameters affects the mine economy and total minable reserve,and it is also affected by different uncertainties which arising from many sources.One of the most critical sources of uncertainty effects on the pit slope design is rock mass geomechanical properties.By comparing the probability of failure resulted from deterministic procedure and probabilistic one,this paper investigated the effects of aforesaid uncertainties on open-pit slope stability in metal mines.In this way,to reduce the effect of variance,it implemented Latin Hypercube Sampling(LHS)technique.Furthermore,a hypothesis test was exerted to compare the effects on two cases in Middle East.Subsequently,the investigation approved high influence of geomechanical uncertainties on overall pit steepness and stability in both iron and copper mines,though on the first case the effects were just over.展开更多
A new dinuclear manganese complex [Mn2（L）2（2,2＇-bipy）2（H2O）512·3H2O has been synthesized with MnSO4·H2O, 2,2＇-bibenzoic acid （H2L） and 2,2＇-bipyridine（2,2＇-bipy） in the mixed solvent ethanol an...A new dinuclear manganese complex [Mn2（L）2（2,2＇-bipy）2（H2O）512·3H2O has been synthesized with MnSO4·H2O, 2,2＇-bibenzoic acid （H2L） and 2,2＇-bipyridine（2,2＇-bipy） in the mixed solvent ethanol and water. It crystallizes in monoclinic, space group Pi with a = 9.9944（10）, b = 21.939（2）, c = 25.628（3） A, a = 108.429（3）, β = 100.613（4）, 7 = 102.821（3）°, V = 4997.9（9） A3, Dc= 1.355 g/cm^3, Z = 2, F（000） = 2108, GOOF = 1.074, the R= 0.0626 and wR= 0.1531. The structure of the complex contains two [Mn2（L）2（2,2＇-bipy）2] units, ten coordinated H2O molecules and three uncoordinated H2O molecules. The fluorescence, thermal stability and magnetic properties of the complex were investigated.展开更多
The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings （TBCs） materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3...The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings （TBCs） materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3 mol% Yb2O3 （GYb-YSZ） powders are synthesized by solid state reaction for 24 h at various temperatures. As temperature increases, stabilizers are dissolved into zirconia matrix gradually. Synthesized at 1 500 °C, GYb-YSZ is basically composed of cubic phase. GYb-YSZ exhibits excellent phase stability and sinters lower than 8YSZ by nearly three times. The thermal conductivity of GYb-YSZ is much lower than that of 8YSZ, and the thermal expansion coefficient of GYb-YSZ is comparable to that of 8YSZ. The influence of Gd2O3 and Yb2O3 co-doping on phase stability, thermal conductivity and sintering of 8YSZ is discussed.展开更多
Oxide-dispersion-strengthened （ODS） ferritic steels are promising candidates for structural applications in the future nuclear reactors. The higher chromium contents of ODS ferritic steels, the better the corrosion ...Oxide-dispersion-strengthened （ODS） ferritic steels are promising candidates for structural applications in the future nuclear reactors. The higher chromium contents of ODS ferritic steels, the better the corrosion resistance, which can meet the harsh corrosion environment of the advanced reactors. However, increasing the Cr content may also lead to the brittleness of the ODS steels when serving at high temperatures. The ODS ferritic steels with different Cr contents （12, 16 and 18 wt% Cr, respectively） were fabricated by mechanical alloying, hot isostatic pressing and forging. Mechanical properties and microstructure evolution of the ODS ferritic steels after aging at 753 K for 2000 h were investigated. It is found that both Vickers hardness and yield strength of 18%Cr ODS ferritic steel were strongly increased and the impact energy was decreased after aging at 753 K. In order to explore the reasons for changes in the mechanical properties, the fracture surfaces were characterized by scanning electron microscopy, and microstructures after aging were observed by transmission electron microscopy. The impact fracture of 18%Cr ODS ferritic steel belongs to quasi-cleavage facture, which is consistent with its very low impact energy. The grain size and dispersed oxide particles of different ODS steels are very stable. M23C6 carbide and M2C carbide were found in 12%Cr ODS steel and 16%Cr ODS steels, respectively.展开更多
A new 1D chain copper coordination polymer [CuE（H2L）2（C10HsN2）（HEO）2]n＇3n（H20） with 2,3-pyridinedi carboxylic acid （H2L） and 2,2＇-bipyridine （2,2＇-bipy） as ligands has been synthesized in the mixed etha...A new 1D chain copper coordination polymer [CuE（H2L）2（C10HsN2）（HEO）2]n＇3n（H20） with 2,3-pyridinedi carboxylic acid （H2L） and 2,2＇-bipyridine （2,2＇-bipy） as ligands has been synthesized in the mixed ethanol and water solvents. Crystal data for this complex are as follows： monoclinic, space group P2Jc, a = 7.7713（7）, b = 27.478（3）, c = 13.2621（13）/1,, fl = 100.6940（10）, V= 2782.8（5） A3, Dc = 1.722 g/cm3, Z = 4, p = 1.61 mm-1, F（000） = 1472, the final R = 0.0363 and wR = 0.0933. In the crystal structure, the whole molecule consists of two cooper ions, two H2L, one 2,2＂-bipy molecule and six water molecules. Each central copper ion is coordinated with three oxygen atoms from two H2L and one water molecule, two nitrogen atoms from one 2,2＇-bipy molecule and two H2L, giving a distorted tetragonal pyramidal geometry. Thermal stability properties of the complex were investigated.展开更多
A new dinuclear copper（Ⅱ） complex [Cu（CH3COO）（C7H5N4）（H2O）]2·3.5H2 O has been hydrothermally synthesized with copper acetate, o-acetamidobenzoic acid and 3-（pyridin-2-yl）-1,2,4-triazole. It crystallize...A new dinuclear copper（Ⅱ） complex [Cu（CH3COO）（C7H5N4）（H2O）]2·3.5H2 O has been hydrothermally synthesized with copper acetate, o-acetamidobenzoic acid and 3-（pyridin-2-yl）-1,2,4-triazole. It crystallizes in the monoclinic space group P21/c, with a = 12.0188（7）, b = 13.7993（8）, c = 8.7488（5） A, β = 101.7350（10）o, V = 1420.67（14） A3, D3 c = 1.568 g/cm, Z = 1, F（000） = 690, the final GOOF = 1.145, R = 0.0437, and w R = 0.1097. The crystal structure shows that the whole molecule consists of two copper ions bridged by two μ2-η1：η0 3-（pyridin-2-yl）-1,2,4-triazole anions. The coordination environment of Cu（Ⅱ） ion is Cu O2N3, giving a distorted square pyramidal geometry. The thermal stability and magnetic properties of the complex were investigated.展开更多
To increase coercivity and thermal stability of sintered Nd–Fe–B magnets for high-temperature applications, a novel terbium sulfide powder is added into（Pr（0.25）Nd（0.75））（30.6）Cu（0.15）Fe（bal）B1（wt.%） b...To increase coercivity and thermal stability of sintered Nd–Fe–B magnets for high-temperature applications, a novel terbium sulfide powder is added into（Pr（0.25）Nd（0.75））（30.6）Cu（0.15）Fe（bal）B1（wt.%） basic magnets. The effects of the addition of terbium sulfide on magnetic properties, microstructure, and thermal stability of sintered Nd–Fe–B magnets are investigated.The experimental results show that by adding 3 wt.% Tb2S3, the coercivity of the magnet is remarkably increased by about 54% without a considerable reduction in remanence and maximum energy product. By means of the electron probe microanalyzer（EPMA） technology, it is observed that Tb is mainly present in the outer region of 2：14：1 matrix grains and forms a well-developed Tb-shell phase, resulting in enhancement of HA, which accounts for the coercivity enhancement.Moreover, compared with Tb2S3-free magnets, the reversible temperature coefficients of remanence（α） and coercivity（β） and the irreversible flux loss of magnetic flow（hirr） values of Tb2S3-added magnets are improved, indicating that the thermal stability of the magnets is also effectively improved.展开更多
La_（0.75）Mg_（0.25）Ni_（2.85）Co_（0.45–x）（AlSn）_x（AlSn）_x（x=0.0,0.1,0.2,0.3） alloys were prepared by magnetic induction melting method, and the phase composition and electrochemical properties were investi...La_（0.75）Mg_（0.25）Ni_（2.85）Co_（0.45–x）（AlSn）_x（AlSn）_x（x=0.0,0.1,0.2,0.3） alloys were prepared by magnetic induction melting method, and the phase composition and electrochemical properties were investigated systematically. The alloys were mainly composed of LaNi5, La2Ni7 and LaNi3 phase, and the cell volume of LaNi5 increased with the Al and Sn contents. For the alloy corresponding to x=0.0, the Cmax and C150 were 348.9 and 185 mA h/g, respectively, then for the alloy electrode with x=0.2, even though the Cmax was only 309.0 mA h/g less than 348.9 mA h/g, the C150 of 231 mA h/g was much higher than 185 mA h/g. And the values of the limit current density, anodic peak current density and hydrogen diffusion coefficient of the La0.75Mg0.25Ni2.85Co0.35（AlS n）0.1（x=0.1） alloy were 1079.5, 1023.8 mA /g and 5.71×10–10 cm2/s, respectively. Which were the highest than that of any other electrodes. These results suggested that the kinetic property of the La_（0.75）Mg_（0.25）Ni_（2.85）Co_（0.45–x）（AlSn）_x（AlSn）_x（x=0.0, 0.1, 0.2, 0.3） electrodes could be improved effectively by adding moderate contents of Al and Sn.展开更多
A new nickel（Ⅱ） complex Ni2（L）2（2,2＇-bipy）2·5.5H2O with methy-bicycle[2.2.1]hept-5-ene-2,3-dicarboxylic acid（H2L） and 2,2？-bipyridine（2,2＇-bipy） as ligands has been synthesized in the mixed solvent ...A new nickel（Ⅱ） complex Ni2（L）2（2,2＇-bipy）2·5.5H2O with methy-bicycle[2.2.1]hept-5-ene-2,3-dicarboxylic acid（H2L） and 2,2？-bipyridine（2,2＇-bipy） as ligands has been synthesized in the mixed solvent DMF and water（v：v = 5：2）. It crystallizes in the triclinic space group P1 with a = 10.414（2）, b = 12.884（3）, c = 16.176（4） A, α = 70.715（5）, β = 80.599（5）, γ = 77.383（6）°, V = 1989.4（8） A^3, Dc = 1.531 g/cm^3, Z = 2, F（000） = 958, GOOF = 1.028, the final R = 0.0808 and w R = 0.2036. The crystal structure shows that the whole molecule consists of two independent dinuclear units, in which two nickel ions are bridged by two μ2-η1：η0 3-carboxylate groups of L2- anions. The coordination environment of Ni（Ⅱ） ion is Ni N2O3, giving a distorted square pyramidal geometry. The thermal stability and electrochemical properties of the complex were investigated.展开更多
Pr1-xLaxCo5-y (x=0, 0.15. 0.25, 0.35,1.0, y=0.5, 0.7, 0.9, 1.0) alloys were investigated. The effect of the variation of x and y on magnetic properties and thermal stability of the alloys were studied. The magnetic pr...Pr1-xLaxCo5-y (x=0, 0.15. 0.25, 0.35,1.0, y=0.5, 0.7, 0.9, 1.0) alloys were investigated. The effect of the variation of x and y on magnetic properties and thermal stability of the alloys were studied. The magnetic properties for the Pr0.85La0.15Co4.3 and Pr0.75La0.25Co4.1 magnets are iHc=368 kA/m, Br=0.91 T, (BH)max=145.6 kJ/m3, αBr=-0.03%/℃ and iHc=568 kA/m,Br=0.8 T, (BH)max=127.2 kJ/m3,αBr,=-0.06%/℃, respectively The phase structures of as-cast alloys and magnets were investigated展开更多
One novel complex [Ni（phen）3],（C8H12O4）·（H2O）14 with hexane dicarboxylic acid and 1,10-phenanthroline has been hydrothermally synthesized and characterized. Crystal data： monoclinic, space group C2/c, a = ...One novel complex [Ni（phen）3],（C8H12O4）·（H2O）14 with hexane dicarboxylic acid and 1,10-phenanthroline has been hydrothermally synthesized and characterized. Crystal data： monoclinic, space group C2/c, a = 2.3475（5）, b = 1.2208（2）, c = 1.9499（4） nm, β= 114.682（3）°, V = 5.0778（16） nm^3, Dc = 1.339 g/cm^3, Z = 4,μ（MoKa） = 0.458 mm^-1, F（000） = 2168, GOOF = 1.014, R = 0.0401 and wR = 0.0961. The nickel（H） center in the title complex is coordinated with six nitrogen atoms of three 1,10-phenanthroline molecules, giving a distorted octahedral coordination geometry. However, the nickel（Ⅱ） ion does not coordinate to the hexane dicarboxylic acid. The complex molecules form a 3D structure through hydrogen bonds. TG analysis shows that the title complex is stable below 240.0 ℃.展开更多
One new cobalt complex [Co（phen）3][（C6Hs）2C（OH）COO]2·7H2O with benzeneacetic acid （BAA）, 1,10-phenanthroline and cobaltous perchlorate has been synthesized by means of solvent method. It crystallizes in t...One new cobalt complex [Co（phen）3][（C6Hs）2C（OH）COO]2·7H2O with benzeneacetic acid （BAA）, 1,10-phenanthroline and cobaltous perchlorate has been synthesized by means of solvent method. It crystallizes in the triclinic system, space group P^-1, with a = 1.14181（13）, b = 1.64417（18）, c = 1.65342（18） nm, α = 74.2830（10）, β= 84.4490（10）, γ = 74.9430（10）°, V = 2.8842（6） nm^3, Dc = 1.359 g/cm^3, Z = 2, F（000） = 1234, R = 0.0621 and wR = 0.1673. The crystal structure shows that the cobalt ion is coordinated with six nitrogen atoms from three 1,10-phenanthroline molecules, giving a distorted octahedral coordination geometry. There are a lot of hydrogen bonds in the complex, from which a two-dimensional network is constructed. The result of TG analysis shows that the title complex is stable below 130.0 ℃.展开更多
Structure, magnetic properties, and thermal stability of ternary Sm1-xTmxCo5 compounds were studied via X-ray diffraction（XRD）, thermal magnetic analysis（TMA）, and magnetic measurements. XRD results show that all ...Structure, magnetic properties, and thermal stability of ternary Sm1-xTmxCo5 compounds were studied via X-ray diffraction（XRD）, thermal magnetic analysis（TMA）, and magnetic measurements. XRD results show that all the compounds have a main phase of hexagonal CaCu5-type crystal structure with small amount of impurity phases; increasing Tm content is associated with contraction of the hexagonal unit cell in the direction of the c axis and expansion of the a and b parameters. TMA results indicate that the Curie temperature（TC） of Sm1-xTmxCo5 compounds gets higher with the increase in Tm content.Magnetic measurements show that both the magnetic anisotropy field（HA） and the magnetization at an applied field of 7 T（M7 T） decrease with the increase of Tm content. However, the thermal stability of both the HAand M7 Tof all the Tm doped compounds is remarkably improved compared with that of the pure SmCo5 compound, leading to the result that both the M7 Tand HAof Sm0.8Tm0.2Co5 .2are higher than those of SmCo5 compound at 473 K, which indicates the good potential of Tm doped compound in the practical applications at elevated temperature.展开更多
We present a first-principles study of the chemisorption of hydrogen on a Stone-Wales （SW） defective carbon nanotube （10,0）. The investigated configurations include four configurations covering single defects and ...We present a first-principles study of the chemisorption of hydrogen on a Stone-Wales （SW） defective carbon nanotube （10,0）. The investigated configurations include four configurations covering single defects and double defects. One hydrogen dimer adsorption is energetically favored on bonds shared by carbon heptagon-heptagon for configurations with the defect parallel to the tube axis compared with the carbon pentagon-hexagon sites for ones with a slanted defect. This different behavior is also demonstrated for hydrogen dimer chain adsorption, the favored site for the former ones is through the defect, which is the nearest neighbor site to defect for the latter ones. It is found that the energy band gaps of hydrogenated configurations may be enlarged or decreased by altering the adsorption site or defect position. The semiconductor-to-metal transition may occur for configurations with the defect or defects parallel to the tube axis due to low electronic localization. Our results highlight the interest of the interaction of multi-factor system by providing a detailed bond and position picture of a hydrogenated defective carbon nanotube （10,0）.展开更多
文摘The aim of present work is to investigate the influencing factors on mechanical property stability of Cu-Mo-Ni alloyed austempered ductile iron （ADI）. The results show that after austenitized at 900℃ for 2 h followed by austempered at 370℃for another 2 h, the mechanical property of the alloyed ADI can reach the Germanite GGG-100 standard, i.e. σb≮1000 MPa,δ≮5%, at 95% confidence level. And the satisfactory mechanical properties were obtained when the alloyed ADI was austenitized at 850℃ to 1 000 ℃ for 1-4 h, and austempered at 355℃ to 400℃ for another 1 h to 4 h. The microstructures, including nodule number, white bright zone content （martensite-containing interdendritic segregation zone） and retained austenite content, can significantly influence the mechanical properties of the ADI. In order to obtain the good combinations of strength and ductility, the volume fraction of white bright zone should he less than 5%, and the retained austenite contents maintain hetween 30 % and 40%. The application of inoculation techniques to increase graphite nodule number can effectively reduce the white bright zone content in the structure.
文摘For functional difference equations with unbounded delay,we characterized the existence of totally stable and asymptotically almost periodic solution by using stability properties of a bounded solution in a certain limiting equation.
基金Supported by the Natural Science Foundation of Hunan Province(No.11JJ9006)Key Project of Science and Technology Plan of Hunan Province(2012FJ2002)the Construct Program of the Key Discipline in Hunan Province
文摘A new complex has been synthesized with o-methylbenzoyl-benzoic acid（HL） and 1,10-phenanthroline（phen） in the mixture of water and ethanol. It crystallizes in monoclinic, space group C2/c with a = 13.6328（18）, b = 17.7876（18）, c = 19.998（2）, β = 104.720（4）o, C54H48N4O11Zn, Mr = 994.33, V = 4690.2（9）3, Dc = 1.408 g/cm3, Z = 4, F（000） = 2072, μ（MoKα） = 0.59 mm-1, R = 0.0736 and wR = 0.2029. The crystal structure shows that the zinc ions are coordinated with two oxygen atoms from two HL molecules and four nitrogen atoms from two phen molecules, forming distorted octahedral coordination geometry. The fluorescent and thermal stability properties of the complex are studied. The result shows that it has one fluorescent emission band at around 412 nm. In addition, the complex is stable under 210 ℃.
基金Project supported by the National Natural Science Foundation of China(51401028)
文摘This paper reports crystal structures, magnetic properties and thermal stability of TbCu7-type Sm（8.5）Fe（（85.8-x）Co（4.5）Zr（1.2）Nbx（x = 0-1.8） melt-spun compounds and their nitrides, investigated by means of X-ray diffraction, vibrating sample magnetometer, flux meter and transmission electron microscope. It is found that the lattice parameter ratio c/a of TbCu7-type crystal structure increases with Nb substitution, which indicates that the Nb can increase the stability of the metastable phase in the Sm-Fe ribbons. Nb substitution impedes the formation of magnetic soft phase a-Fe in which reversed domains initially form during the magnetization reversal process. Meanwhile, Nb substitution refines grains and leads to homogeneous micro structure with augmented grain boundaries. Thus the exchange coupling pining field is enhanced and irreversible domain wall propagation gets suppressed. As a result, the magnetic properties are improved and the irreversible flux loss of magnets is notably decreased. A maximum value 771.7 kA/m of the intrinsic coercivity H（cj） is achieved in the 1.2 at% substituted samples.The irreversible flux loss for 2 h exposure at 120 ℃ declines from 8.26% for Nb-free magnets to 6.32% for magnets with 1.2 at% Nb substitution.
基金Supported by the Natural Science Foundation of Hunan Province (No. 11JJ9006)Key Project of Science and Technology Plan of Hunan Province (2012FJ2002)+1 种基金Science and Technology Plan of Hunan Province (2012GK3031, 2012WK3029)the Construct Program of Key Discipline in Hunan Province
文摘A new complex Cu2（o-C6H5COC6H5COO）4（C10H8N2）2（H2O）2 with 2-benzoylben- zoic acid and 2,2′-bipyridine as ligands has been synthesized in mixed methanol and water solvent. Crystal data are as follows： monoclinic, space group Co, a = 14.0133（14）, b = 16.0409（16）, c = 30.372（3） A, β = 100.8950（10）°, V = 6704.1（12） A3, Dc = 1.364 g/cm3, Z = 8,μ（MoKa） = 0.704 mml, F（000） = 2840, the final R= 0.0552 and wR = 0.1431. In the crystal structure, the whole molecule consists of two copper ions, four 2-benzoylbenzoic acid molecules, two 2,2′-bipyridine molecules and two water molecules. Each central copper ion is coordinated with two nitrogen atoms from one 2,2′-bipyridine molecule and three oxygen atoms from two 2-benzoylbenzoic acids and one water molecule, respectively, giving a distorted tetragonal pyramidal geometry. Thermal stability properties of the complex were investigated.
基金Supported by the Construct Program of the Key Discipline in Hunan Province and Key Project of Production Plan of Hengyang City(2013)
文摘A new dinuclear copper（II） complex [Cu2（L）2（phen）2]·5H2O （1） with bicycle[2.2.1 ]hept- 2-en-5, 6-dicarboxylic acid （H2L） and 1,10-phenanthroline （phen） as ligands has been synthesized in the mixed solvents of ethanol and water. It crystallizes in the monoclinic space group P21/c, with a = 17.925（4）, b = 19.908（4）, c = 11.235（2） A, β = 97.65（3）°, V= 3973.4（14） A3, Dc = 1.552 g/cm^3, Z = 8, F（000） = 1910, the final GOOF = 1.056, R= 0.0519 and wR= 0.1293. The crystal structure shows that the whole molecule consists of two independent dinuclear units, in which two copper ions are bridged by twoμ2-η1 ：η0-3-carboxylate groups of L^2- anions. The fluorescence and thermal stability properties of 1 were studied. The results show that 1 has an intense fluorescent emission at around 381 rim. The TG analysis shows that I is stable below 143 ℃.
文摘In open-pit mines,pit slope as one of the important parameters affects the mine economy and total minable reserve,and it is also affected by different uncertainties which arising from many sources.One of the most critical sources of uncertainty effects on the pit slope design is rock mass geomechanical properties.By comparing the probability of failure resulted from deterministic procedure and probabilistic one,this paper investigated the effects of aforesaid uncertainties on open-pit slope stability in metal mines.In this way,to reduce the effect of variance,it implemented Latin Hypercube Sampling(LHS)technique.Furthermore,a hypothesis test was exerted to compare the effects on two cases in Middle East.Subsequently,the investigation approved high influence of geomechanical uncertainties on overall pit steepness and stability in both iron and copper mines,though on the first case the effects were just over.
基金Supported by the Key Project of Science and Technology Plan of Hunan Province(2012FJ2002)Science and Technology Committee of Hengyang(2013KG77)the Construct Program of the Key Discipline in Hunan Province
文摘A new dinuclear manganese complex [Mn2（L）2（2,2＇-bipy）2（H2O）512·3H2O has been synthesized with MnSO4·H2O, 2,2＇-bibenzoic acid （H2L） and 2,2＇-bipyridine（2,2＇-bipy） in the mixed solvent ethanol and water. It crystallizes in monoclinic, space group Pi with a = 9.9944（10）, b = 21.939（2）, c = 25.628（3） A, a = 108.429（3）, β = 100.613（4）, 7 = 102.821（3）°, V = 4997.9（9） A3, Dc= 1.355 g/cm^3, Z = 2, F（000） = 2108, GOOF = 1.074, the R= 0.0626 and wR= 0.1531. The structure of the complex contains two [Mn2（L）2（2,2＇-bipy）2] units, ten coordinated H2O molecules and three uncoordinated H2O molecules. The fluorescence, thermal stability and magnetic properties of the complex were investigated.
基金National Natural Science Foundation of China (50771009, 50731001)National Basic Research Program of China (2010CB631200)Research Fund for the Doctoral Program of Higher Education of China (20070006017)
文摘The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings （TBCs） materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3 mol% Yb2O3 （GYb-YSZ） powders are synthesized by solid state reaction for 24 h at various temperatures. As temperature increases, stabilizers are dissolved into zirconia matrix gradually. Synthesized at 1 500 °C, GYb-YSZ is basically composed of cubic phase. GYb-YSZ exhibits excellent phase stability and sinters lower than 8YSZ by nearly three times. The thermal conductivity of GYb-YSZ is much lower than that of 8YSZ, and the thermal expansion coefficient of GYb-YSZ is comparable to that of 8YSZ. The influence of Gd2O3 and Yb2O3 co-doping on phase stability, thermal conductivity and sintering of 8YSZ is discussed.
文摘Oxide-dispersion-strengthened （ODS） ferritic steels are promising candidates for structural applications in the future nuclear reactors. The higher chromium contents of ODS ferritic steels, the better the corrosion resistance, which can meet the harsh corrosion environment of the advanced reactors. However, increasing the Cr content may also lead to the brittleness of the ODS steels when serving at high temperatures. The ODS ferritic steels with different Cr contents （12, 16 and 18 wt% Cr, respectively） were fabricated by mechanical alloying, hot isostatic pressing and forging. Mechanical properties and microstructure evolution of the ODS ferritic steels after aging at 753 K for 2000 h were investigated. It is found that both Vickers hardness and yield strength of 18%Cr ODS ferritic steel were strongly increased and the impact energy was decreased after aging at 753 K. In order to explore the reasons for changes in the mechanical properties, the fracture surfaces were characterized by scanning electron microscopy, and microstructures after aging were observed by transmission electron microscopy. The impact fracture of 18%Cr ODS ferritic steel belongs to quasi-cleavage facture, which is consistent with its very low impact energy. The grain size and dispersed oxide particles of different ODS steels are very stable. M23C6 carbide and M2C carbide were found in 12%Cr ODS steel and 16%Cr ODS steels, respectively.
基金Supported by the Natural Science Foundation of Hunan Province(No.11JJ9006)Key Project of Science and Technology Plan of Hunan Province(2012FJ2002)+1 种基金Science and Technology Plan of Hunan Province(2012GK3031,2012WK3029)the Construct Program of the Key Discipline in Hunan Province
文摘A new 1D chain copper coordination polymer [CuE（H2L）2（C10HsN2）（HEO）2]n＇3n（H20） with 2,3-pyridinedi carboxylic acid （H2L） and 2,2＇-bipyridine （2,2＇-bipy） as ligands has been synthesized in the mixed ethanol and water solvents. Crystal data for this complex are as follows： monoclinic, space group P2Jc, a = 7.7713（7）, b = 27.478（3）, c = 13.2621（13）/1,, fl = 100.6940（10）, V= 2782.8（5） A3, Dc = 1.722 g/cm3, Z = 4, p = 1.61 mm-1, F（000） = 1472, the final R = 0.0363 and wR = 0.0933. In the crystal structure, the whole molecule consists of two cooper ions, two H2L, one 2,2＂-bipy molecule and six water molecules. Each central copper ion is coordinated with three oxygen atoms from two H2L and one water molecule, two nitrogen atoms from one 2,2＇-bipy molecule and two H2L, giving a distorted tetragonal pyramidal geometry. Thermal stability properties of the complex were investigated.
基金Supported by the Construct Program of the Key Discipline in Hunan Province and Key Project of Production Plan of Hengyang City(2013)
文摘A new dinuclear copper（Ⅱ） complex [Cu（CH3COO）（C7H5N4）（H2O）]2·3.5H2 O has been hydrothermally synthesized with copper acetate, o-acetamidobenzoic acid and 3-（pyridin-2-yl）-1,2,4-triazole. It crystallizes in the monoclinic space group P21/c, with a = 12.0188（7）, b = 13.7993（8）, c = 8.7488（5） A, β = 101.7350（10）o, V = 1420.67（14） A3, D3 c = 1.568 g/cm, Z = 1, F（000） = 690, the final GOOF = 1.145, R = 0.0437, and w R = 0.1097. The crystal structure shows that the whole molecule consists of two copper ions bridged by two μ2-η1：η0 3-（pyridin-2-yl）-1,2,4-triazole anions. The coordination environment of Cu（Ⅱ） ion is Cu O2N3, giving a distorted square pyramidal geometry. The thermal stability and magnetic properties of the complex were investigated.
基金Project supported by the Science Funds from the Ministry of Science and Technology,China(Grant Nos.2014DFB50130 and 2011CB612304)the National Natural Science Foundation of China(Grant Nos.51172168 and 51072139)
文摘To increase coercivity and thermal stability of sintered Nd–Fe–B magnets for high-temperature applications, a novel terbium sulfide powder is added into（Pr（0.25）Nd（0.75））（30.6）Cu（0.15）Fe（bal）B1（wt.%） basic magnets. The effects of the addition of terbium sulfide on magnetic properties, microstructure, and thermal stability of sintered Nd–Fe–B magnets are investigated.The experimental results show that by adding 3 wt.% Tb2S3, the coercivity of the magnet is remarkably increased by about 54% without a considerable reduction in remanence and maximum energy product. By means of the electron probe microanalyzer（EPMA） technology, it is observed that Tb is mainly present in the outer region of 2：14：1 matrix grains and forms a well-developed Tb-shell phase, resulting in enhancement of HA, which accounts for the coercivity enhancement.Moreover, compared with Tb2S3-free magnets, the reversible temperature coefficients of remanence（α） and coercivity（β） and the irreversible flux loss of magnetic flow（hirr） values of Tb2S3-added magnets are improved, indicating that the thermal stability of the magnets is also effectively improved.
基金Project supported by the National Natural Science Foundation of China(51271061,51571065)Foundation of Guangxi Educational Committee(2013YB006)the Key Laboratory of Guangxi for Nonferrous Metals and Materials Processing Technology
文摘La_（0.75）Mg_（0.25）Ni_（2.85）Co_（0.45–x）（AlSn）_x（AlSn）_x（x=0.0,0.1,0.2,0.3） alloys were prepared by magnetic induction melting method, and the phase composition and electrochemical properties were investigated systematically. The alloys were mainly composed of LaNi5, La2Ni7 and LaNi3 phase, and the cell volume of LaNi5 increased with the Al and Sn contents. For the alloy corresponding to x=0.0, the Cmax and C150 were 348.9 and 185 mA h/g, respectively, then for the alloy electrode with x=0.2, even though the Cmax was only 309.0 mA h/g less than 348.9 mA h/g, the C150 of 231 mA h/g was much higher than 185 mA h/g. And the values of the limit current density, anodic peak current density and hydrogen diffusion coefficient of the La0.75Mg0.25Ni2.85Co0.35（AlS n）0.1（x=0.1） alloy were 1079.5, 1023.8 mA /g and 5.71×10–10 cm2/s, respectively. Which were the highest than that of any other electrodes. These results suggested that the kinetic property of the La_（0.75）Mg_（0.25）Ni_（2.85）Co_（0.45–x）（AlSn）_x（AlSn）_x（x=0.0, 0.1, 0.2, 0.3） electrodes could be improved effectively by adding moderate contents of Al and Sn.
基金Supported by the Construct Program of the Key Discipline in Hunan ProvinceKey Project of Industrial Science and Technology Support of Hengyang City(2015KG23)
文摘A new nickel（Ⅱ） complex Ni2（L）2（2,2＇-bipy）2·5.5H2O with methy-bicycle[2.2.1]hept-5-ene-2,3-dicarboxylic acid（H2L） and 2,2？-bipyridine（2,2＇-bipy） as ligands has been synthesized in the mixed solvent DMF and water（v：v = 5：2）. It crystallizes in the triclinic space group P1 with a = 10.414（2）, b = 12.884（3）, c = 16.176（4） A, α = 70.715（5）, β = 80.599（5）, γ = 77.383（6）°, V = 1989.4（8） A^3, Dc = 1.531 g/cm^3, Z = 2, F（000） = 958, GOOF = 1.028, the final R = 0.0808 and w R = 0.2036. The crystal structure shows that the whole molecule consists of two independent dinuclear units, in which two nickel ions are bridged by two μ2-η1：η0 3-carboxylate groups of L2- anions. The coordination environment of Ni（Ⅱ） ion is Ni N2O3, giving a distorted square pyramidal geometry. The thermal stability and electrochemical properties of the complex were investigated.
文摘Pr1-xLaxCo5-y (x=0, 0.15. 0.25, 0.35,1.0, y=0.5, 0.7, 0.9, 1.0) alloys were investigated. The effect of the variation of x and y on magnetic properties and thermal stability of the alloys were studied. The magnetic properties for the Pr0.85La0.15Co4.3 and Pr0.75La0.25Co4.1 magnets are iHc=368 kA/m, Br=0.91 T, (BH)max=145.6 kJ/m3, αBr=-0.03%/℃ and iHc=568 kA/m,Br=0.8 T, (BH)max=127.2 kJ/m3,αBr,=-0.06%/℃, respectively The phase structures of as-cast alloys and magnets were investigated
基金Project supported by the Fund of Science and Technology Committee of Hunan Province (2008FJ3023)the Research Award Fund for Outstanding Young Teachers of Hengyang Normal University (2006)Key Subject Fund of Hunan Province
文摘One novel complex [Ni（phen）3],（C8H12O4）·（H2O）14 with hexane dicarboxylic acid and 1,10-phenanthroline has been hydrothermally synthesized and characterized. Crystal data： monoclinic, space group C2/c, a = 2.3475（5）, b = 1.2208（2）, c = 1.9499（4） nm, β= 114.682（3）°, V = 5.0778（16） nm^3, Dc = 1.339 g/cm^3, Z = 4,μ（MoKa） = 0.458 mm^-1, F（000） = 2168, GOOF = 1.014, R = 0.0401 and wR = 0.0961. The nickel（H） center in the title complex is coordinated with six nitrogen atoms of three 1,10-phenanthroline molecules, giving a distorted octahedral coordination geometry. However, the nickel（Ⅱ） ion does not coordinate to the hexane dicarboxylic acid. The complex molecules form a 3D structure through hydrogen bonds. TG analysis shows that the title complex is stable below 240.0 ℃.
基金Supported by the Fund of Science and Technology Committee of Hunan Province (2007SK4012)The Construct Program of the Key Disipline in Hunan Province
文摘One new cobalt complex [Co（phen）3][（C6Hs）2C（OH）COO]2·7H2O with benzeneacetic acid （BAA）, 1,10-phenanthroline and cobaltous perchlorate has been synthesized by means of solvent method. It crystallizes in the triclinic system, space group P^-1, with a = 1.14181（13）, b = 1.64417（18）, c = 1.65342（18） nm, α = 74.2830（10）, β= 84.4490（10）, γ = 74.9430（10）°, V = 2.8842（6） nm^3, Dc = 1.359 g/cm^3, Z = 2, F（000） = 1234, R = 0.0621 and wR = 0.1673. The crystal structure shows that the cobalt ion is coordinated with six nitrogen atoms from three 1,10-phenanthroline molecules, giving a distorted octahedral coordination geometry. There are a lot of hydrogen bonds in the complex, from which a two-dimensional network is constructed. The result of TG analysis shows that the title complex is stable below 130.0 ℃.
基金financially supported by the State Key Development Program of Basic Research of China (No. 2010CB934600)State Key Laboratory of Advanced Metals and Materials (No. 2011-ZD02)the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality (No. 009000543113507)
文摘Structure, magnetic properties, and thermal stability of ternary Sm1-xTmxCo5 compounds were studied via X-ray diffraction（XRD）, thermal magnetic analysis（TMA）, and magnetic measurements. XRD results show that all the compounds have a main phase of hexagonal CaCu5-type crystal structure with small amount of impurity phases; increasing Tm content is associated with contraction of the hexagonal unit cell in the direction of the c axis and expansion of the a and b parameters. TMA results indicate that the Curie temperature（TC） of Sm1-xTmxCo5 compounds gets higher with the increase in Tm content.Magnetic measurements show that both the magnetic anisotropy field（HA） and the magnetization at an applied field of 7 T（M7 T） decrease with the increase of Tm content. However, the thermal stability of both the HAand M7 Tof all the Tm doped compounds is remarkably improved compared with that of the pure SmCo5 compound, leading to the result that both the M7 Tand HAof Sm0.8Tm0.2Co5 .2are higher than those of SmCo5 compound at 473 K, which indicates the good potential of Tm doped compound in the practical applications at elevated temperature.
基金Supported by the Education Department of Henan Province under Grant No 14B140018
文摘We present a first-principles study of the chemisorption of hydrogen on a Stone-Wales （SW） defective carbon nanotube （10,0）. The investigated configurations include four configurations covering single defects and double defects. One hydrogen dimer adsorption is energetically favored on bonds shared by carbon heptagon-heptagon for configurations with the defect parallel to the tube axis compared with the carbon pentagon-hexagon sites for ones with a slanted defect. This different behavior is also demonstrated for hydrogen dimer chain adsorption, the favored site for the former ones is through the defect, which is the nearest neighbor site to defect for the latter ones. It is found that the energy band gaps of hydrogenated configurations may be enlarged or decreased by altering the adsorption site or defect position. The semiconductor-to-metal transition may occur for configurations with the defect or defects parallel to the tube axis due to low electronic localization. Our results highlight the interest of the interaction of multi-factor system by providing a detailed bond and position picture of a hydrogenated defective carbon nanotube （10,0）.
