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1.
In this paper, the mechanical behavior of the scarf lap joints (SLJs) bonded with adhesive (Vinylester Atlac 580) under a tensile load was analyzed. The effects of scarf angle at the interface strain distributions of SLJs were examined. The stress analyses were performed via three dimensional Finite Element Method (3D-FEM). The 3D-FEM code employed was Ansys (12.0). Experimental results were compared with the 3D-FEM results and were found quite reasonable. The results indicated that the maximum values of the normalized εx strain values were determined at θ = 60° in all joints. 相似文献
2.
通过对整个塔里木盆地绿洲分布与水系分布概况进行野外调查与室内数据分析,探讨塔里木盆地绿洲分布与水资源的关系,证明了绿洲与水资源的内在联系.二者的关系是:塔里木盆地绿洲分布由水系分布限定的.大部分大小绿洲都是位于在河流流域.塔里木盆地绿洲规模大小随水资源开发利用变化而不断地变化. 相似文献
3.
Brendan F. Abrahams Stuart R. Batten Martin J. Grannas Hasan Hamit Bernard F. Hoskins Richard Robson 《Angewandte Chemie (International ed. in English)》1999,38(10):1475-1477
The shortest circuits in the three-dimensional network with (12,3) topology of solvated Ni(tpt)(NO3)2 pass through one another (see picture). This network based upon interlinked double helices occupies a unique position in the set of (n,3) nets. tpt=tri-4-pyridyl-1,3,5-triazine. 相似文献
4.
Investigation of Luminescence Properties of Eu3+, Dy3+ and Gd3+ Doped MgAl2Si2O8 Red‐emitting Phosphors
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Rare‐earth‐doped aluminosilicates of alkaline earth MgAl2Si2O8: Eu3+, Dy3+ and MgAl2Si2O8: Eu3+, Gd3+ were synthesized by the solid state reaction method at 1300 oC. The phosphors were characterized by X‐ray powder diffraction (XRD), photoluminescence (PL), thermoluminescence (TL) and scanning electron microscopy (SEM). X‐ray powder diffraction studies show that the phosphors were crystallized in the triclinic crystal system. The phosphors show characteristic broad band phosphorescence of Eu3+. This broad band phosphorescence has red emission bands in the range of 580–705 nm corresponding to 5D0 → 7Fj (j:0,2,3,4) transitions of Eu3+. 相似文献
5.
Esra ??r??r Nilgun Ozpozan Kalaycioglu 《Journal of Thermal Analysis and Calorimetry》2012,110(3):1179-1183
Mn4+ doped and Eu3+, Yb3+ co-doped MgAl2Si2O8-based phosphors were prepared by conventional solid state reaction at 1,300?°C. They were characterized by thermogravimetry, differential thermal analysis, X-ray powder diffraction, photoluminescence, and scanning electron microscopy. The luminescence mechanism of the phosphors, which showed broad red emission bands in the range of 600?C715?nm and had a different maximum intensity when activated by UV illumination, was discussed. Such a red emission can be attributed to the intrinsic 2 E????4 A 2 transitions of Mn4+. 相似文献
6.
In this research, the effects of doping Lu2O3 to α‐Bi2O3 in the range of 0.01 < x < 0.10 in a series of different mole fractions (1% < n < 10% mole ratios) was studied. Beside, heat treatment was performed by applying a cascade temperature rise in the range of 700‐800 °C for 72 hours and new phases were obtained in the (Bi2O3)1‐x(Lu2O3)x system. After heat treatment for 72 hours at 800 °C; mixtures, containing 2‐8% mole Lu2O3, formed a tetragonal phase. As a result of subjecting mixtures, containing 9% and 10% mole Lu2O3, to a quenching process at 825 °C, tetragonal phases were obtained. With the help of XRD, the crystal systems and lattice parameters of the solid solutions were obtained and their characterization was carried out. Thermal measurements were made by using a simultaneous DTA/TG system. The total conductivity (σT) in the β‐Bi2O3 doped with Lu2O3 was measured using the four‐probe DC method. 相似文献
7.
We have achieved, for the first time to our knowledge, lasing in a new type of telluride-tungstate glass host doped with neodymium: Nd3+:(0.8)TeO2-(0.2)WO3. Lasing was obtained at 1065 nm with two samples containing 0.5 mol% and 1.0 mol% Nd2O3. During gain-switched operation, slope efficiencies of 12% and 10% were obtained with the 0.5 mol% and 1.0 mol% doped samples, respectively, at a pulse repetition rate of 1 kHz. Judd-Ofelt analysis was further employed to determine the emission cross section σe at 1065 nm from the absorption spectra and lifetime data. The emission cross section from the Judd-Ofelt analysis came to 3.23 ± 0.09 × 10−20 cm2, in reasonable agreement with the value of 2.0 ± 0.13 × 10−20 cm2 obtained from the analysis of laser threshold data. 相似文献
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9.
In this article, N‐(2‐aminophenyl)arylsulfonamides (1–5) were successfully synthesized by the reaction of o‐phenylenediamine and various benzenesulfonyl chlorides. The Schiff base derivatives (1a–f; 4e) of those compounds were obtained using different aldehydes. Then, a series of neutral‐four coordinate Pd(II) complexes (6–10) were prepared from the reaction of Pd(OAc)2 and 1–5. On the other hand, when we tried to synthesize Pd(II) complexes containing Schiff base/sulfonamide ligands, two different situations were observed. Generally, when an electron‐donating group was attached to the imine fragment (1a–d) except for 1f, the Schiff base hydrolyzed and 6 was isolated. When an electron‐withdrawing group was attached to the imine fragment (1e, 4e), neutral four‐coordinate Pd(II) complexes (11–13) bearing Schiff base/sulfonamide ligands were isolated. The synthesized compounds were characterized by FT‐IR, elemental analysis and NMR spectroscopy. The complexes were used as a catalyst in the oxidation reaction of benzyl alcohol to benzaldehyde in the presence of H5IO6 in acetonitrile. All complexes showed satisfactory catalytic activity. The highest catalytic activity was obtained with 9. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
10.
This paper reports the Gd3+, Dy3+, Tb3+ and Lu3+ doped CaTiO3 based phosphors were synthesized by modified solid‐state reaction method and its crystal structure and luminescent properties were investigated. The X‐ray diffraction patterns (XRD) showed that the phosphors sintered at 1000 °C for 2 h were a pure CaTiO3 phases. The optimization of reaction conditions were carried out by thermal gravimetry and differential thermal analysis methods (DTA/TG). Surface and elemental analyses were performed by using on SEM instrument. The excitation and emission spectras were recorded by photoluminescence spectrophotometer (PL). 相似文献