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61.
Masaki Kashiwara Takahiro Kawai Toshio Oshima 《Communications in Mathematical Physics》1978,60(2):97-130
We use the holonomic character of Feynman integrals to describe their singularity structure explicitly in some simple cases. The results in §1 show that under moderate conditions Feynman amplitudes can be locally expressed essentially in terms of Legendre functions near the points where two positive- Landau-Nakanishi surfaces meet. Related topics such as hierarchical principle in perturbation theory are also discussed in terms of holonomic systems involved. In §4 we use the concrete expressions for Feynman amplitudes obtained in §1 to discuss the validity of Sato's conjecture.Supported in part by NSF MCS 75-2333Supported in part by NSF GP 36269 相似文献
62.
A total of 13 samples of diamond separates studied so far, all contain excess 244Pu fission xenon. On the other hand, none of the SiC separates contains excess 244Pu fission xenon, while 5 out of 10 samples of graphite separates studied so far contain excess 244Pu fission xenon. 相似文献
63.
The spectrum of magnetic resonance is typically affected by a modulated structure in an incommensurate phase, resulting in the broadened spectrum characterized by ‘edge singularities’. We demonstrate that the modulated structure in the crystal where molecular motion exists is responsible for the narrowing of the spectrum in the fast motional region by means of the simulation of 2H NMR spectrum of [Mg(H2O)6][SiF6]. The program developed by combining the theories of phase solitons in the incommensurate phase and motional change of 2H NMR spectrum was used for the simulation. We obtained a good agreement between the theoretical 2H NMR spectrum and experimental one for [Mg(H2O)6][SiF6]. 相似文献
64.
Masami Sawada Yasuo Okumura Hitoshi Yamada Yoshio Takai Shigetoshi Takahashi Takahiro Kaneda Keiji Hirose Soichi Misumi 《Journal of mass spectrometry : JMS》1993,28(12):1525-1528
Using fast atom bombardment (FAB) mass spectrometry (MS), cross-chiral relationships were confirmed for the first time for the diasteromeric host-guest complexations between the chiral crown ether host (1) and the chiral organic ammonium ion guest (2) on the basis of the relative peak intensities (RPI). Both host–guest combinations (R, R, R, R) – 1, (R) – 2 and (S, S, S, S) – 1, (S) – 2 obviously provided larger RPI values than the combination of both (R, R, R, R) – 1, (S) – 2 and (S, S, S, S) – 1, (R) – 2 by a factor of 1.6 as an averaged value: 1.87 (n = 4)/1.16 (n = 4) = 1.6. These results are consistent with the expected stabilities of the host-guest complexations by CPK model examinations. Successfully observed cross-chiral examinations strongly suggest a potentially useful FABMS/RPI methodology for rapidly searching newly designed and synthesized crown ether-like host compounds with a higher degree of enantioselectivity. 相似文献
65.
Re-calculation of the244Pu ages of lunar rocks 10057 and 12013 indicates that, while the former started to retain its xenon (4,189 ?74 +45 ) million years ago, the latter was formed at a much later time, after the extinct nuclide244Pu had essentially decayed away. 相似文献
66.
The intensities of the ΔM = ± 1 component of the 7fo→ 5D2 transition in D3 complexes containing the [ EuO9] cluster, and of other d-d or f-f transitions in D3 complexes with the yz- and xz-components of the electric quadrupole as the leading moment, are found to be dependent upon the polarizability anisotropy of the ligands. The expectation is supported by determinations of the single-crystal absorption intensities of Na3 [Eu(diglycollate)3]·2NaClO4·6H2O and [Eu(H2O)9] (C2H5SO4)3. 相似文献
67.
A series of iminodiacetic acid (IDA)-linked polyamides (DpPyPyPy-IDA-PyPyPyDp) were prepared and constitute polyamides joined head-to-head by a functionalizable five-atom linker. It was found that the IDA linker exerts a unique influence over the DNA binding conformation differing from both the beta-alanine (extended) or gamma-aminobutyric acid (hairpin) linkers, resulting in cooperative parallel side-by-side 2:1 binding in an extended conformation most likely with a staggered versus stacked alignment. A generalized variant of a fluorescent intercalator displacement (FID) assay conducted on a series of hairpin deoxyoligonucleotides containing a systematically varied A/T-rich binding-site size was used to distinguish between the binding modes of the IDA-linked polyamides. 相似文献
68.
Takakazu Yamamoto Abla Mahmut Masahiro Abe Shin‐Ichi Kuroda Tatsuya Imase Shintaro Sasaki 《Journal of Polymer Science.Polymer Physics》2005,43(16):2219-2224
An alternating copolymer, Copoly‐1 , of thiophene and N‐(phenylethynyl)pyrrole was prepared by palladium‐catalyzed polycondensation. Powder X‐ray diffraction (XRD) analysis indicated that Copoly‐1 formed a stacked packing structure with doubly‐running polymer main chains. Optical data support the molecular and packing structures of Copoly‐1 . © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2219–2224, 2005 相似文献
69.
Dialkoxydichlorosilanes ((RO)2SiCl2, R = alkyl) react almost completely with interlayer silanol groups in a layered silicate octosilicate to create a new crystalline silicate structure consisting of new five-membered rings arranged regularly on both sides of the silicate layers. The introduction of dialkoxysilyl groups to the interlamellar region of layered silicates with regular reaction sites provides a new methodology for the design and construction of novel crystalline silicate frameworks by a soft chemical route. 相似文献
70.
Electrochemically driven clathration/declathration of ferrocene and its derivatives by a nanometer-sized coordination cage 总被引:1,自引:0,他引:1
The electrochemical, NMR, and crystallographic studies clearly indicate that the clathration and declathration of ferrocene and its derivatives in a self-assmbled Pd(II)-linked nanometer-sized cage can be controlled by the oxidation state of the guest. Namely, the guests are clathrated when they are reduced but declathrated when they are oxidized. The process is rapid on the NMR time scale but slow on the CV time scale. 相似文献