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101.
102.
LIANG Bunüa ZHANG Zhenyua b WANG Zhipingb CHEN Baiminga a Mechanical Engineering Department Lanzhou Polytechnical College Lanzhou China b State Key Laboratory of New Nonferrous Metal Materials Lanzhou University of Technology China 《稀有金属(英文版)》2010,29(3):270-275
FeNiCr alloys with various amounts of La2O3 powders were thermally sprayed onto steel substrate. Electron probe microscopy analysis (EPMA), X-ray photoelectron spectroscopy (XPS), and an Optimol SRV oscillating friction and wear tester in a ball-on-disc contact con-figuration were employed to investigate the properties of the sprayed coatings. The results show that rare earth can refine the microstructure effectively and make the element distribution uniform, which leads to the improvement in the properties of the coatings. Meanwhile, the wear rate of the FeNiCr alloy with 1.5% La2O3 is smaller than those of the other coatings. Interestingly, the rare earth can reduce the friction coef-ficient and act as a self-lubricant in the oxide debris layer formed on the worn surface in friction. The wear mechanism of the coatings is oxi-dation wear, and a large amount of counterpart material is transferred to the coatings. 相似文献
103.
针对目前润滑自修复技术生成的修复层厚度较薄,难以修复较严重磨损表面的不足,研制了含铟、锡和锌三种软金属添加剂的新型磨损自修复润滑剂。在摩擦磨损试验机上,考察了使用该润滑剂的钢?钢面接触摩擦副的磨损自修复行为及其摩擦学性能。用X射线能谱(EDS)和扫描电镜(SEM)分析了修复表面的主要化学元素和自修复涂层的厚度。用淬冷试验测试了涂层与基体的结合强度。结果表明,研制的铟锡锌润滑脂能在钢表面摩擦形成约30μm厚度的自修复涂层,涂层与基体结合性能良好,修复后的钢表面有良好的减摩抗磨性能。 相似文献
104.
Loï C Chardigny JM Cordelet C Leclere L Genty M Ginies C Noël JP Sébédio JL 《Lipids》2000,35(8):911-918
To study the ability of long-chain trans fatty acids (FA) to be incorporated and metabolized into endothelial cells, bovine aortic endothelial cells were incubated
with medium enriched eicosapentaenoic acid (EPA) bound to albumin (M2) or one of its geometrical isomers: 20∶5 5c,8c,11t,14c,17c(M3), 20∶5 5c,8c,11c,14c,17t(M4), or 20∶5 5c,8c,11t,14c,17t(M5). After 48 h of incubation, supernatant and cells were harvested and their lipids were analyzed, including prostacyclin
synthesis. EPA and 22∶5n−3 of endothelial cells incubated with M2 were, respectively, three and two times higher than in control
cells (incubated in M1, without any fatty acid added), whereas 22∶6n−3 increased only in the supernatant, suggesting its release
after biosynthesis. However, 18∶2n−6 and 22∶4n−6 decreased (about 30%). Trans 20∶5 isomers represented 4.7, 3.9, and 5.2% of total phospholipid FA in endothelial cells incubated with M3, M4, and M5,
respectively. They were elongated into trans 22∶5 and trans 24∶5, as revealed by gas chromatography-mass spectrometry and gas chromatography-Fourier transform infrared analysis. In
cells incubated with M2, M3, M4, and M5, prostacyclin synthesis was inhibited by 49.0, 62.5, 60.5, and 72.0%, respectively.
This effect may be due to less available arachidonic acid in the cells and to a competition between EPA isomers and AA at
the level of cyclooxygenase pathway, as it was demonstrated that 20∶5 Δ17t was metabolized by this enzyme. 相似文献
105.
YE Jinqin a LI Haidong a HE Qinglin b a Department of Mathematical Physical Sciences Henan Institute of Engineering Zhengzhou China b Department of Physics Jiaozuo Teacher’s College Jiaozuo China 《稀有金属(英文版)》2011,30(5):501-504
Polycrystalline samples of Bi 1.5 Pb 0.5 Sr 2-x La x Co 2 O y (x = 0.1, 0.2, 0.3) with a layered structure were prepared by solid-state reaction method. All samples are p-type semiconductors. The thermoelectric properties, namely, the electric resistivity (ρ), Seebeck coefficient (S), and power factor (S 2 /ρ) of the samples are dependent on chemical composition. The values of ρ, S, and S 2 /ρ increase with an increase in temperature for all samples. The substitution of Pb 2+ for Bi 3+ and La 3+ for Sr 2+ improves the thermoelectric properties of the Bi 2 Sr 2 Co 2 O y system owing to the simultaneous decrease of electric resistivity and increase of Seebeck coefficient. As a result, the optimal thermoelectric property has been obtained in Bi 1.5 Pb 0.5 Sr 1.7 La 0.3 Co 2 O y and the power factor can reach 2.1 × 10-4 W·m-1 K-2 at 998 K. 相似文献
106.
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108.
核函数的度量研究进展 总被引:1,自引:0,他引:1
核函数的度量(简称核度量)研究两个核函数(或一个核函数与另一个目标函数)之间相似性的度量方法,是核函数研究中的一个重要课题。系统综述了核度量的研究状况以及目前的研究进展,分析了典型核度量方法的特点及不足,并凝炼了其进一步研究的方向。 相似文献
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110.