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31.
抗磨可靠性寿命的加速试验与预测 总被引:3,自引:0,他引:3
在工程实际中,对新机器零件的抗磨可靠性寿命进行评估或预测非常重要,但是,由于磨损是一种受多因素制约的随机过程,目前在实验室广泛采用的模拟磨损试验,不仅周期较长,而且预测误差也比较大。因此,提出了一种在保持磨损机相似的前提下合理选用高PV值的抗磨可靠性寿命加速试验的新方法。 相似文献
32.
<正>Two new eudesmane derivatives were isolated from the leaves and flowers of Verbesina virginica,along with the known 6-O-β-E -p-coumaroyl-4α-hydroxyeudesmane(1).Their structures were determined as 6-O-β-Z-p-coumaroyl-4α-hydroxyeudesmane(2) and 6-O-α-E-p-coumaroyl-1β-4α-dihydroxyeudesmane(3) by spectroscopic methods. 相似文献
33.
Dual-sensitive probe of 1-imidazole-2-(5-benzoacridine)-ethanone (IBAE) for the determination of free amines with fluorescence detection and online highly sensitive atmospheric chemical ionization-mass spectrometry identification (APCI-MS) has been developed. 2-(Benzoacridine)-5-acetic acid (BAAA) reacts with coupling agent N,N′-carbonyldiimidazole (CDI) to form a highly activated amide intermediate 1-imidazole-2-(5-benzoacridine)-ethanone (IBAE), which is dual-sensitive probe. The amide intermediate (IBAE) reacts preferably with amines in dimethylformamide (DMF) solvent to give the high yields of derivatives. IBAE-amine derivatives are not only sensitive to fluorescence but also to MS ionizable efficiency. The percent ionization δ values change from 0 to 57.32% in aqueous acetonitrile and from 0 to 62.14% in aqueous methanol. The relative standard deviations of the peak areas with fluorescence detection for each amine are <1.24% (40 ng/ml, n = 6). The fluorescence detection limits (at a signal-to-noise ratio of 3) are in the range of 0.15-0.50 ng/ml. The online APCI-MS detection limits are in the range of 2.07-8.51 ng/ml (at a signal-to-noise ratio of 3). Therefore, the facile IBAE intermediate derivatization allowed the development of a highly sensitive and specific method for the quantitative analysis of trace levels of amines in environmental water. 相似文献
34.
Jinmao You Yanyan Fu Zhiwei Sun Yourui Suo 《Analytical and bioanalytical chemistry》2010,396(7):2657-2666
2-(5-Benzoacridine)ethyl-p-toluenesulfonate (BAETS), a dual-sensitive probe, was reacted with bile acids in the presence of K2CO3 catalyst in dimethyl sulfoxide (DMSO) solvent to give BAETS–bile acid derivatives. Derivatives exhibited intense fluorescence
(FL) with an excitation maximum at λ
ex 270 nm and an emission maximum at λ
em 510 nm. MS analysis using APCI-MS indicated that derivatives had excellent APCI-MS ionizability with percentage ionization
δ values changing from 0 to 88.83% in aqueous acetonitrile and from 0 to 89.15% in aqueous methanol. The collision induced
dissociation spectra of m/z [M + H]+ contained specific fragment ions at m/z [M + H−H2O]+, [M + H−2H2O]+, [M + H−3H2O]+, 347.3, and 290.1. Repeatability was good for LC separation of BAETS–bile acid derivatives with aqueous acetonitrile as mobile
phase. The relative standard deviations (RSDs) of retention time and peak area at 6.6 nmol mL−1 levels with fluorescence detection (FL) were from 0.045 to 0.072% and from 2.16 to 2.73%, respectively. Excellent linear
responses were observed, with regression coefficients >0.9995. The FL detection limits (S/N = 3) were in the range of 18.0–36.1 fmol. The online APCI-MS detection limits are in the range of 500–790 fmol (at a signal-to-noise
ratio of 3). 相似文献
35.
Limin Han Guangbin Zhang Ning Zhu Ruijun Xie Quanling Suo Meihua Luo Linhong Weng 《Journal of Cluster Science》2010,21(4):789-801
Two novel bimetallic complexes, [Cr(CO)3(η
6-C6H5)–C≡C–C6H4–Fc] (Fc = C5H5FeC5H4] (1) and [Cr(CO)3(η
6-C6H5)–C ≡ C–Fc–C(CH3)2–Fc] (3), were synthesized by the Sonogashira coupling reaction. By using of (1) and (3) as ligands to react with Co2(CO)8, two others novel polymetallic complexes, [Cr(CO)3(η
6-C6H5){Co2(CO)6-η
2-μ
2-C≡C–}–C6H4–Fc] (2) and [Cr(CO)3(η
6-C6H5){Co2(CO)6-η
2-μ
2-C≡C–}Fc–C(CH3)2–Fc] (4) were obtained. Four carbonyl complexes were characterized by elemental analysis, FT-IR, NMR and MS. The molecular structures
of complexes (1), (2) and (4) were determined by single crystal X-ray diffraction. The interactions among the ferrocenyl,
Cr(CO)3 and Co2(CO)6-η
2-μ
2-C≡C– units were investigated by cyclic voltammetry. 相似文献
36.
Yibo Lei Bingbing Suo Yusheng Dou Yubin Wang Zhenyi Wen 《Journal of computational chemistry》2010,31(8):1752-1758
Multireference configuration interaction with single and double excitations (MRCISD) as well as its analytic CI gradients has been implemented in the semiempirical framework. The hole‐particle symmetry and a mixed driven model for computing coupling coefficients have been used in the new code that allows us to perform MRCI and gradient calculations with higher efficiency and less storage requirements. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010 相似文献
37.
Shuai Ye Hongli Suo Ziping Wu Min Liu Yan Xu Lin Ma Meiling Zhou 《Physica C: Superconductivity and its Applications》2011,471(7-8):265-269
The YBCO films with BaSnO3 (BSO) particles were prepared on LAO (0 0 1) substrates by metal organic deposition using trifluoroacetates (TFA-MOD) via introducing SnCl4 powders into the YBCO precursor solution. It was found that with the increase of the SnCl4 contents, the slower decomposition and higher temperature for nucleation during the reaction were requested compared to that of pure YBCO film. The YBCO films with different contents of Sn with dense surface and well c-alignment were obtained under optimized heat treatment, and the BaSnO3 phases were detected by XRD analysis. Litter effect of BSO particles on the Tc and Jc values of YBCO films was found. All YBCO films with BSO particles had Tc values over 90 K and Jc values over 1 MA/cm2. A significant enhancement of Jc was observed for YBCO films with BSO particles compared to that of pure YBCO film by the field dependence of Jc values. The best property was obtained for YBCO film with 6 mol.% Sn at 77 K under magnetic field. The results showed that the Jc value of YBCO film with 6 mol.% Sn was enhanced by a factor of 2 in 2 T, and over a factor of 10 beyond 4 T compared to that of pure YBCO film. 相似文献
38.
Z. Zhang H. Suo L. Ma T. Zhang M. Liu M. Zhou 《Physica C: Superconductivity and its Applications》2011,471(21-22):908-911
The co-doped MgB2 bulk samples have been synthesized using an in situ reaction processing. The additives is 8 wt.% SiC nano powders and 10 wt.% [(CH2CHCOO)2Zn]n poly zinc acrylate complexes (PZA). A systematic study was performed on samples doped with SiC or PZA and samples co-doped with both of them. The effects of doping and co-doping on phase formation, microstructure, and the variation of lattice parameters were studied. The amount of substituted carbon, the critical temperature (Tc) and the critical current density (Jc) were determined. The calculated lattice parameters show the decrease of the a-axis, while no obvious change was detected for c-axis parameter in co-doped samples. This indicates that the carbon was substituted by boron in MgB2. The amount of substituted carbon for the co-doped sample shows an enhancement compared to that of the both single doped samples. The co-doped samples perform the highest Jc values, which reaches 3.3 × 104 A/cm2 at 5 K and 7 T. It is shown that co-doping with SiC and organic compound is an effective way to further improve the superconducting properties of MgB2. 相似文献
39.
Martin M.F.Choi 《中国化学快报》2009,20(2):210-212
A novel mode-filtered light gas sensor has been reported.It was constructed by inserting an optical fiber deposited by a thin silicone cladding of cryptophane A into a fused-silica capillary.When different concentration of methane gas was introduced to the sensor,the phenomenon that mode-filtered light intensity decreased with the increasing concentration of methane was observed. And a linear relationship was obtained within the methane concentration range of 0.0-16.0%(v/v).The detection limit was 0.06% ... 相似文献
40.