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61.
Max Wilke Karen Appel Laszlo Vincze Christian Schmidt Manuela Borchert Sakura Pascarelli 《Journal of synchrotron radiation》2010,17(5):669-675
A confocal set‐up is presented that improves micro‐XRF and XAFS experiments with high‐pressure diamond‐anvil cells (DACs). In this experiment a probing volume is defined by the focus of the incoming synchrotron radiation beam and that of a polycapillary X‐ray half‐lens with a very long working distance, which is placed in front of the fluorescence detector. This set‐up enhances the quality of the fluorescence and XAFS spectra, and thus the sensitivity for detecting elements at low concentrations. It efficiently suppresses signal from outside the sample chamber, which stems from elastic and inelastic scattering of the incoming beam by the diamond anvils as well as from excitation of fluorescence from the body of the DAC. 相似文献
62.
Nami Choi Kumiko Asano Sakura Watanabe Wataru Ando 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):379-380
1,3-Bis[tris(trimethylsilyl)methyl]-2,4,5-trichalcogena-1,3-disilabicyclo[1.1.1]pentanes display unusual short bridgehead Si---Si distances despite the absence of formal Si—Si bonds, and chalcogen---chalcogen interactions are observed by nmr, X-ray analysis and electronic spectroscopy. 相似文献
63.
Anthranilamide (AAM) serves as a bifunctional modifier on the boron atom in catalytic transformations of arylboronic acids. It makes boronyl groups unreactive in Suzuki-Miyaura coupling and promotes Ru-catalyzed ortho-silylation. Suzuki-Miyaura coupling of AAM-modified bromophenylboronic acids with tolylboronic acid gave 1,1'-biaryl-4-boronic acid bearing AAM on the boron atom, which subsequently underwent Ru-catalyzed ortho-silylation at the 3-position by virtue of the ortho-directing effect of the AAM group. 相似文献
64.
The one-loop worldsheet quantum corrections to the energy of spinning strings on R×S3 within AdS5×S5 are reexamined. The explicit expansion in the effective 't Hooft coupling λ′=λ/J2 is rigorously derived. The expansion contains both analytic and non-analytic terms in λ′, as well as exponential corrections. Furthermore, we pin down the origin of the terms that are not captured by the quantum string Bethe ansatz, which only produces analytic terms in λ′. It is shown that the analytic terms arise from string fluctuations within the S3, whereas the non-analytic and exponential terms, which are not captured by the Bethe ansatz, originate from the fluctuations in all directions within the supersymmetric sigma model on AdS5×S5. We also comment on the case of spinning string in AdS3×S1. 相似文献
65.
K Okimura N Sakura S Ohta K Kurosawa T Hashimoto 《Chemical & pharmaceutical bulletin》1992,40(6):1500-1503
Contractile activity of porcine neuromedin U-25 (p-NMU-25) and various neuromedin U (NMU) peptide fragment amides was examined on chicken crop smooth muscle preparation. The relative activity (expressed as RA value) of p-NMU-25 to porcine neuromedin U-8 (p-NMU-8) was 5.51 +/- 0.09, and p-NMU-25 (15-25) was the most potent fragment with an RA value of 7.78 +/- 0.05. All C-terminal 11-peptide amides of rat, rabbit, and frog NMU peptides retained activity about three-fold higher than the corresponding C-terminal 8-peptide amides. The peptide segment Asn15-Arg-Arg17 of p-NMU-25, as well as the corresponding positions of various NMU peptides: Ser13-Gly-Gly15 of rat NMU and Ser15-Arg-Gly17 of rabbit and frog NMUs, appeared to be involved in the structural requirements for increased contractile activity in the assay system. 相似文献
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68.
Keisuke Kurita Hikaru Sakata Yoshio Iwakura Mutsuo Koyanagi 《Journal of polymer science. Part A, Polymer chemistry》1978,16(3):667-676
Poly(N-acylamides) were synthesized by polyaddition of bisketenimines with dicarboxylic acids. Yields and inherent viscosities of these polymers were low, presumably because of side reactions. The thermal stability and solubility of the polymers were studied. 相似文献
69.
Shigenobu Aoyagi Makoto Koyanagi Megumi Takahashi Kazuaki Shimada Yuji Takikawa 《Tetrahedron letters》2007,48(11):1915-1918
Thioketene S,S-dioxides 2 were successfully generated through [3,3] sigmatropic rearrangement of alkynyl propargyl sulfones 1 and the formation of 2 was confirmed by trapping experiment using cyclohexene or allyltrimethylsilane affording a [2+2] cycloadduct 5. In situ generated thioketene S,S-dioxides 2 underwent facile conversion into allenynes 3 in moderate yields, via formation and subsequent [1,2] shift of vinylidene carbenes. 相似文献
70.
Molecular formulae for the isotropic and anisotropic scattering are derived by considering the internal field acting upon a molecule within a dense medium and its fluctuation caused by density fluctuations. The anisotropic scattering formula of classical theory is retained but modified by the factors of the internal field. The new formula for the isotropic scattering depends sensitively on the principal values of the optical polarizability tensor and on the parameters describing the anisotropic internal field. Assuming the internal field to be given by the semimacroscopic approach of the Onsager-Scholte model with an ellipsoidal cavity, comparison of the calculated isotropic Rayleigh factor with the experimental value allows a prediction of the degree of the cavity anisotropy for different liquid densities. 相似文献