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For a smooth curve in the Euclidean spaces, the total squared curvature is defined as the integral of the square of the curvature. If one takes three points on the curve which are close to one another, the reciprocal of the radius of the circle passing through those points approximates the curvature. We use this to approximate the total squared curvature and study its convergence rate. 相似文献
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Hyun-Joung Kwon Jeong-Ah Seo Takashi Iwahashi Yukio Ouchi Doseok Kim Hyung Kook Kim Yoon-Hwae Hwang 《Current Applied Physics》2013,13(1):271-279
This study examined the acoustic phonon mode of ionic liquids consisting of 1-alkyl-3-methyl-imidazolium family (CnMIM) cations with n values ranging from 2 to 10 and bis(trifluoromethylsulfonyl)amide (TFSA) anion in the temperature range from 300 K to 100 K. [CnMIM]+[TFSA]? showed depolarized (VH) components of Brillouin peaks at temperatures below the glass transition temperature when n is larger than 4. On the other hand, in the case of ionic liquids with different anions, such as [C4MIM]+[BF4]?, [C4MIM]+[PF6]? and [C8MIM]+[BF4]?, the VH component of Brillouin peaks was not observed in the temperature range investigated. The dielectric loss spectra showed that the temperature dependence of alkyl chain domain relaxation of all ionic liquids followed the Arrhenius law and showed an increase in activation energy at the temperature where the VH component of Brillouin peak appeared. These results suggest that the observed depolarized component of Brillouin peak might originate from uniquely induced polarization in the 2nd domain composed of head groups of cations and anions. 相似文献
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Metal‐Free Enantioselective Oxidative Arylation of Alkenes: Hypervalent‐Iodine‐Promoted Oxidative C−C Bond Formation 下载免费PDF全文
Mio Shimogaki Prof. Dr. Morifumi Fujita Prof. Dr. Takashi Sugimura 《Angewandte Chemie (International ed. in English)》2016,55(51):15797-15801
The enantioselective oxyarylation of (E)‐6‐aryl‐1‐silyloxylhex‐3‐ene was achieved using a lactate‐based chiral hypervalent iodine(III) reagent in the presence of boron trifluoride diethyl etherate. The silyl ether promotes the oxidative cyclization, and enhances the enantioselectivity. In addition, the corresponding aminoarylation was achieved. 相似文献
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Gel-based proteomics reveals potential novel protein markers of ozone stress in leaves of cultivated bean and maize species of Panama 总被引:1,自引:0,他引:1
Torres NL Cho K Shibato J Hirano M Kubo A Masuo Y Iwahashi H Jwa NS Agrawal GK Rakwal R 《Electrophoresis》2007,28(23):4369-4381
We examined responses of cultivated bean (Phaseolus vulgaris L. cv. IDIAP R-3) and maize (Zea mays L. cv. Guarare 8128) plants exposed to ozone (O(3)) using a leaf injury assessment and proteomics approach. Plants grown for 16 days in greenhouse were transferred to an O(3) chamber and exposed continuously to 0.2 ppm O(3) or filtered pollutant-free air for up to 72 h. CBB-stained gels revealed changes in ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) protein. By Western analysis changes in marker proteins for O(3) damage in leaves by 1-DE were checked. In bean leaves, two superoxide dismutase (SOD) protein (19 and 20 kDa) were dramatically decreased, while ascorbate peroxidase (APX, 25 kDa), small heat shock protein (HSP, 33 kDa), and a naringenin-7-O-methyltransferase (NOMT, 42 kDa) were increased by O(3). In maize leaves, expression levels of catalase (increased), SOD (decreased), and APX (increased) were drastically changed by O(3) depending on the leaf stage, whereas crossreacting HSPs (24 and 30 kDa) and NOMT (41 kDa) proteins were strongly increased in O(3)-stressed younger leaves. These results indicated a clear modulation of oxidative stress-, heat shock-, and secondary metabolism-related proteins by O(3). Finally, 2-DE at 72 h after O(3) exposure revealed changes (induction/suppression) in expression levels of 25 and 12 protein spots in bean and maize leaves, respectively. Out of these, ten and nine nonredundant proteins in bean and maize, respectively, were identified by MS. A novel pathogenesis-related protein 2 may serve as a potential marker for O(3) stress in bean. 相似文献
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K. Kanai T. Nishi T. Iwahashi Y. Ouchi K. Seki Y. Harada S. Shin 《Journal of Electron Spectroscopy and Related Phenomena》2009,174(1-3):110
Electronic structures of ionic liquids formed by 1-buthyl-3-alkylimidazolium ion [Cnmim]+ (n = 4 and 8) with various inorganic and organic anions have been investigated by ultraviolet photoemission, X-ray photoemission, inverse photoemission and soft X-ray emission spectroscopies (SXES). The comparison of the calculated density of states with the observed spectra revealed that the molecular orbital energies of these ionic liquids are significantly affected by the electrostatic Madelung potential among the ions. The SXES results clearly show that the both highest occupied and lowest unoccupied states of [C4mim]+PF6− are derived from the cation as a result of strong Madelung potential. On the other hand, the SXES results show the valence electronic structures of ionic liquids with larger anion molecules, [Cnmim]+Tf2N− and [Cnmim]+OTf− are contributed from the both cation and anion. 相似文献
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The oxidation of linoleic acid yields isomeric acyl hydroperoxides. In order to clarify the relation between the lipid peroxide-derived radicals and the toxicity of the lipid peroxide, identification of the lipid-derived radicals is essential. In this paper, high performance liquid chromatography/electron spin resonance/mass spectrometry (HPLC/EPR/MS) analysis of the radicals was performed for the reaction mixture containing 9-hydroperoxy-(10E,12E)-octadeca-10,12-dienoic acid (9EE-OOH) [or 13-hydroperoxy-(9Z,11E)-octadeca-9,11-dienoic acid (13ZE-OOH)] under an aerobic condition or an anaerobic condition. Following radicals were identified from 9EE-OOH (or 13EZ-OOH) by using high performance liquid chromatography/electron spin resonance spectrometry (HPLC/EPR) and HPLC/EPR/MS: pentyl radical and isomers of epoxylinoleic acid radicals from 13EZ-OOH under an anaerobic condition; 7-carboxyheptyl radical and pentyl radical from 13EZ-OOH under an aerobic condition; 7-carboxyheptyl radical and pentyl radical from 9EE-OOH under an aerobic condition; 7-carboxyheptyl radical from 9EE-OOH under an anaerobic condition. These results showed that the formation of the respective radical species depends on oxygen concentration in the reaction mixtures to a great extent. 相似文献