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71.
[reaction: see text] A series of oligo(octithienylene-diethynylene)s alternately composed of octithiophene and diacetylene units have been prepared by a random Eglinton coupling reaction among mono- and diethynyloctithiophenes. The largest compound isolated in the oligomeric series is comprised of twelve octithiophene units and eleven diacetylene units, and its molecular length reaches ca. 43 nm, which is the longest among single-component conjugated nanomolecules. 相似文献
72.
Pairing correlations are studied numerically in a hole-doped spin-fermion model. Simulations performed on up to 12 x 12 clusters provide indications of D-wave superconductivity away from half-filling comparable to those of the 2D t-J model. The pairing correlations are the strongest in the direction perpendicular to the dynamic stripes that appear in the ground state at some densities. An optimal doping, where correlations are maximized, was observed at approximately 25% doping with an estimated T(c) approximately 100-200 K, in qualitative agreement with high-T(c) cuprates' phenomenology, while pairing correlations are suppressed by static stripe inhomogeneities. 相似文献
73.
Hashi K Shimizu T Goto A Kiyoshi T Matsumoto S Wada H Fujito T Hasegawa K Yoshikawa M Miki T Ito S Hamada M Hayashi S 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2002,156(2):318-321
We have developed a 920-MHz NMR system and performed the proton NMR measurement of H(2)O and ethylbenzene using the superconducting magnet operating at 21.6 T (920 MHz for proton), which is the highest field produced by a superconducting NMR magnet in the persistent mode. From the NMR measurements, it is verified that both homogeneity and stability of the magnet have a specification sufficient for a high resolution NMR. 相似文献
74.
Kaoru Hagiwara Dieter Haidt Seiji Matsumoto 《The European Physical Journal C - Particles and Fields》1998,2(1):95-122
We update our previous work on an analysis of the electroweak data by including new and partly preliminary data available
up to the 1996 summer conferences. The new results on the partial decay widths into and hadrons now offer a consistent interpretation of all data in the minimal standard model. The value extracted for the strong
interaction coupling constant agrees well with determinations in other areas. New constraints on the universal parameters , and are obtained from the updated measurements. No signal of new physics is found in the , , analysis once the SM contributions with GeV and those of not a too heavy Higgs boson are accounted for. The naive QCD-like technicolor model is now ruled out at the
99% CL even for the minimal model with . In the absence of a significant new physics effect in the electroweak observables, constraints on masses of the top quark,
, and Higgs boson, , are derived as a function of and the QED effective coupling . The preferred range of depends rather strongly on the actual value of : for , while for at 95% CL. Prospects due to forthcoming improved measurements of asymmetries, the mass of the weak boson
, and are discussed. Anticipating uncertainties of 0.00020 for , 20 MeV for , and 2 GeV for , the new physics contributions to the , , parameters will be constrained more severely, and, within the SM, the logarithm of the Higgs mass can be constrained to about
. The better constraints on , , and on within the minimal SM should be accompanied with matching precision in .
Received: 18 June 1997 相似文献
75.
Issei Akamatsu Seiji Takata 《Journal of Quantitative Spectroscopy & Radiative Transfer》1977,18(4):459-461
The ξ-functions for an atmospheric argon plasma have been evaluated within an accuracy of ±9% over the visible region (400–800 nm) at several temperatures in the 104 K region. The plasma has been produced by a low-voltage, high-current arc jet and its parameters have been determined by using a recently published value for the atomic transition probability. 相似文献
76.
Kenji Sumiya Tsunetaka Matsumoto Seiji Watatani Fumttada Hayama 《Journal of Physics and Chemistry of Solids》1979,40(12):1097-1102
Highly coercive magnetic powder was obtained by growing cobalt ferrite on the surface of γ-Fe2O3 particles in highly alkaline suspensions containing cobalt and ferrous ions in a Co/Fe molar ratio = . The mechanism of the growth and the structure of cobalt ferrite on γ-Fe2O3 were studied by X-ray diffraction and electron diffraction techniques. Results show that crystals of cobalt ferrite CoFe2O4 with a spinel type crystal structure of lattice constant 8.415 Å grew epitaxially on γ-Fe2O3. The acicular direction of the epitaxially grown Co-γ-Fe2O3 as well as γ-Fe2O3 was in the [01] direction. It was found that from the lattice constant value and the half width of X-ray diffraction peaks, the lattice constant epitaxially grown Co γ-Fe2O3 may be attributed to two kinds of crystals, viz., seed γ-Fe2O3 () which was partly reduced to Fe3O4, and surface layer CoFe2O4 (). The crystal growth in the interface between the seed crystals and the growth layer was affected by the crystal structure of the seed crystals. The lattice constant of CoFe2O4 which was located in the vicinity of the interface was almost equal to that of the seed crystals. 相似文献
77.
Takashi Okazaki Seiji Ōkubo Yūichi Hoshino Kanji Fujii 《Physics letters. [Part B]》1979,85(1):107-110
The validity of the assumption that decays into mesons proceed via ω, φ and ?0 poles followed by cascade decays is examined. is well reproduced by using and the B → ωπ helicity structure. The structure of OZI-violating transitions including the electromagnetic contribution is examined, and compared with the data on inclusive decay. 相似文献
78.
A novel coordination gelator exhibits reversible chromatic and sol-gel phase-transition phenomena triggered by thermal and chemical stimuli. 相似文献
79.
80.
Numata M Koumoto K Mizu M Sakurai K Shinkai S 《Organic & biomolecular chemistry》2005,3(12):2255-2261
We already found that beta-1,3-glucan polysaccharides form polymeric complexes with certain polynucleotides, but the parallel vs. anti-parallel orientation in those complexes had remained unsolved. In this paper, this controversial problem has been discussed for curdlan/oligo(dA) complexes utilizing two different energy transfer techniques. The first system consists of a combination of fluorescein-labeled curdlan and 3'-(or 5'-)tetramethyl-rhodamine (TAMRA)-labeled oligo(dA). The second system utilizes gold nanoparticles: that is, two curdlan chains were linked by a disulfide bond and after complexation with oligo(dA), the complex was immobilized on gold nanoparticles. In this system, TAMRA was attached to the 3'(or 5') end of oligo(dA) and the gold particle acted as a fluorescence quencher (energy acceptor). These experiments have led us to conclude that in the curdlan/oligo(dA) complex, parallel orientation is more favourable than anti-parallel orientation. These findings have enabled us to envision a clearer image for the complexation mode between beta-1,3-glucan polysaccharides and polynucleotides. 相似文献