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991.
报导了以测量角透过光强方法为基础的GRIN透镜数值孔径测试仪的工作原理、特点和测量结果,其测量不确定度U(2σ)达到0.8%。 相似文献
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Zhao‐Ying Liu Ling‐Li Huang Dong‐Mei Chen Zong‐Hui Yuan 《Rapid communications in mass spectrometry : RCM》2010,24(7):909-918
Mequindox, 3‐methyl‐2‐quinoxalinacetyl‐1,4‐dioxide, is a quinoxaline‐N,N‐dioxide used in veterinary medicine as a antibacterial in China. To gain an understanding of the interspecies differences in the metabolism of mequindox, comparative metabolite profiles were qualitatively and quantitatively carried out for the first time in rat, chicken and pig liver microsomes by high‐performance liquid chromatography combined with hybrid ion trap/time‐of‐flight mass spectrometry. A total of 14 metabolites were characterized based on their accurate MS2 spectra and known structure of mequindox. The in vitro metabolic pathways of mequindox in three species were proposed as N→O group reduction, carbonyl reduction, N→O group reduction followed by carbonyl reduction or methyl mono‐hydroxylation. A metabolic pathway involving N→O group reduction followed by acetyl group mono‐hydroxylation in only chicken was also proposed. There was also quantitative species difference for mequindox metabolism in three species. 1‐Desoxymequindox was the main metabolite in all species, but otherwise there were some qualitative interspecies differences in mequindox major metabolites. This work has revealed biotransformation characteristics of mequindox among different species, and moreover will further facilitate the explanations of the biological activities of mequindox in animals. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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996.
We derive a sharp nonasymptotic bound of parameter estimation of the L1/2 regularization.The bound shows that the solutions of the L1/2 regularization can achieve a loss within logarithmic factor of an ideal mean squared error and therefore underlies the feasibility and effectiveness of the L1/2regularization.Interestingly,when applied to compressive sensing,the L1/2 regularization scheme has exhibited a very promising capability of completed recovery from a much less sampling information.As compared with the Lp(0 p 1) penalty,it is appeared that the L1/2 penalty can always yield the most sparse solution among all the Lp penalty when 1/2 ≤ p 1,and when 0 p 1/2,the Lp penalty exhibits the similar properties as the L1/2 penalty.This suggests that the L1/2 regularization scheme can be accepted as the best and therefore the representative of all the Lp(0 p 1) regularization schemes. 相似文献
997.
In this investigation, chiral thiophosphoramide 3d was easily prepared from chiral (1R,2R)-1,2-diphenylethylenediamine and then applied as an efficient chiral ligand in the catalytic asymmetric arylation reactions of various aromatic aldehydes. The corresponding diarylmethanol products were produced with good to excellent yields (up to 98%) and enantioselectivities (up to 94%). The recovery of chiral ligand 3d could be as high as 96%. 相似文献
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Hua Guo Yu Ting Hu Da Qiang Cang Yi Jin Li Xin Wang Xiang Li Cheng Hao Bai Yan Bing Zong 《中国化学快报》2010,21(2):229-233
<正>Two calculation models of mass action concentrations for CaO-MgO-SiO_2-Al_2O_3-Cr_2O_3 penta-slag was presented whether 3CaO·Cr_2O_3·3SiO_2 was existence or not.Equilibrium mass action concentration of each element structure was gained.And the models results were compared with experimental activity.The final results illustrated the model without 3CaO·Cr_2O_33SiO_2 was suit for reality.The model could response the element structure of slag as well. 相似文献
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与高阶导数有公共不动点的整函数 总被引:1,自引:0,他引:1
本文证明了如果f是非常数整函数满足超级σ_2(f)<1/2,k是一正整数,如果f和f(k)有公共不动点z CM,那么f~((k))(z)-z=c(f(z)-z),其中c是非零常数. 相似文献