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51.
We have measured the photoluminescence spectra of indirect excitons localized by alloy fluctuation in GaSe1?xSx solid solutions. The presence of the mobility edge for the localized exciton states is essential for explaining the observed luminescence spectra. 相似文献
52.
An extension of the authors' previous methods is presented for the optimal control of flood propagation via a dam gate, based on a combination of the finite element and gradient methods. It is assumed in previous papers that the control duration is the same as the duration of the flood. However, the duration of the control does not necessarily coincide with that of the flood flow. To overcome this difficulty, the gradient method is applied to solve the free terminal time-fixed terminal condition problem. It is shown that the water elevation can be controlled exactly the same as with the previously presented method. It is also shown that the computation can be terminated at a far shorter time than the terminal time of the flood. 相似文献
53.
In the dimethyl sulfoxide (DMSO)-metal oxide oxidation of alcohol to carbonyl compound, molybdenum oxides were the only useful catalytic reagents, and various alcohols were oxidized to the corresponding carbonyl compounds in high yields. 相似文献
54.
Nomura A Uyeda TQ Yumoto N Tatsu Y 《Chemical communications (Cambridge, England)》2006,(34):3588-3590
To design a nanoscale biodevice that can be controlled by an external stimulus, we have introduced photochemical switching peptides derived from the kinesin C-terminus domain into the kinesin-microtubule in vitro motility system. 相似文献
55.
Tojo S Kitagawa M Enomoto K Kato Y Takasu Y Kumakura M Takahashi Y 《Physical review letters》2006,96(15):153201
We observed high-resolution photoassociation spectra of laser-cooled ytterbium (Yb) atoms in the spin-forbidden 1S0 - 3P1 intercombination line. The rovibrational levels in the 0u+ state were measured for red detunings of the photoassociation laser ranging from 2.9 MHz to 1.97 GHz with respect to the atomic resonance. The rotational splitting of the vibrational levels near the dissociation limit were fully resolved due to the sub-MHz linewidth of the spectra in contrast to previous measurements using the spin-allowed singlet transition. In addition, from a comparison between the spectra of 174Yb and those of 176Yb, a d-wave shape resonance for 174Yb is strongly suggested. 相似文献
56.
Abstract The molecular and crystal structure of a 1:1 co-crystal of 4,4′-dimethyl-7,7′-bi([1,2,5]thiadiazolo[3,4-b]pyridylidene)–chloranilic acid, (1), has been determined by X-ray diffraction at the monoclinic space group P21/c with cell parameters of a = 8.422(6), b = 7.343(4), c = 16.112(7) ?, β = 104.988(8)°, V = 962.5(10) ?3 and Z = 2. In the crystal structure, two components connect via the intermolecular O–H···N hydrogen bonds [2.804(4) ?] and S···O
heteroatom interaction [2.945(3) ?] with R
2
2(7) couplings to form a unique and infinite one-dimensional supramolecular tape structure. The calculations of (1) at the HF/6-31G(d), MP2/6-31G(d), and B3LYP/6-31G(d) levels can almost reproduce X-ray geometry. In addition, the distances
of the intermolecular O–H···N and S···O interactions by MP2/6-31G(d) and B3LYP/6-31G(d) levels agree well with those in the
crystal. The calculated binding energies corrected BSSE and ZPE are −4.487 (HF), −7.473 (MP2), and −5.640 (B3LYP) kcal/mol.
The results suggest that the complex (1) is very stable and the dispersion interaction is significantly important for the attractive intermolecular interaction in
(1). The NBO analysis has revealed that the n(N) → σ*(O–H) interaction gives the strongest stabilization to the system and the major interaction for the intermolecular
S···O contact is n(O) → σ*(S–N).
Index Abstract In the crystal structure of the title compound, the molecules are linked by intermolecular O–H···N hydrogen bonds and short
S···O heteroatom interactions with R
2
2(7) couplings to construct a unique and infinite one-dimensional supramolecular tape structure.
相似文献
57.
Shunsaku Shiotani Seiji Yamaguchi Masahide Kurosaki Hajime Yokoyama Yoshiro Hirai 《Journal of heterocyclic chemistry》1999,36(2):403-412
Difuro[3,2-c:3′,2′-e]pyridine 1 , a new tricyclic heteroaromatic, has been prepared for the first time. Bromination of 1 with molecular bromine gave 3-bromo 7 , 8-bromo 7′ and 3,8-dibromo derivative 8 ; nitration with fuming nitric acid yielded 2-nitro compound 9 , while nitration with a mixture of fuming nitric acid and sulfuric acid gave 2,7-dinitro derivative 10 ; formylation with n-butyllithium and dimethylformamide gave 2-formyl 11 , 7-formyl 11′ , and 2,7-diformyl compound 12. The N-oxide 14 of 1 afforded 4-cyano compound 15 by cyanation with trimethylsilyl cyanide, 4-chloro compound 16 by chlorination with phosphorus oxychloride, and 4-acetoxyl compound 17 by acetoxylation with acetic anhydride. 相似文献
58.
Yoshiro Tajitsu 《Macromolecular Symposia》2004,212(1):201-208
Polylactic acid (PLA) is a polymer material on which biodegradability research has been the most advanced. PLA is a chiral polymer in which molecules containing asymmetric carbon atoms have a helical structure. Two optical isomers of PLA exist, PLLA (poly(L-lactic acid)) and PDLA (poly(D-lactic acid)). In this study, using various physical processes, we fabricated various samples such as oriented PLLA film, PLLA fiber, rolled PLLA film and forged PLLA plate. We observed a large optical rotatory power ρ in the cylindrical plate fabricated using a forging process. ρ of forged PLLA plates is 7200°/mm which is approximately 300 times larger than that of α-quartz. 相似文献
59.
60.
Hideaki Tanaka Takahisa Akatsuka Toru Ohe Yoshiro Ogoma Koji Abe Yoshiyuki Kondo 《先进技术聚合物》1998,9(2):150-154
A fluorescence probe, fluorescein isothiocyanate (FITC), was introduced to proteins, and the morphology of protein-adsorbed stearic acid monolayer was observed by fluorescence microscopy and Brewster angle microscopy (BAM) in order to analyze images. At a low protein concentration, the surface pressure increased as shown by a sigmoidal curve. A number of stripe patterns in the BAM images increased and the shapes became clear with increasing concentration of proteins. Simultaneously, the size of circular islands also became small, and finally disappeared. These results suggest that the very large stripe patterns in the BAM image show the assembly of both proteins and stearic acid molecules, and small circular islands show only the stearic acid molecules. © 1998 John Wiley & Sons, Ltd. 相似文献