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41.
We present a theoretical calculation on the time-variability of the fine-structure constant to fit the result of the recent precise analysis of the measurement of the QSO absorption lines. We find the parameters of the scalar-tensor theory to be determined much more accurately than fitting the accelerating universe itself, but leading not to easy detections of the effect on the equation of state of the dark energy in the earlier epochs. 相似文献
42.
We have made high density amorphous ice (HDA) by the pressure-induced amorphization of hexagonal ice at 77 K and measured the volume change on isobaric heating in a pressure range between 0.1 and 1.5 GPa. The volume of HDA on heating below ~0.35?GPa increases, while the volume of HDA on heating above ~0.35?GPa decreases. The polarized OH-stretching Raman spectra of the relaxed HDAs are compared with that of the unannealed HDA. The relaxed HDAs are prepared at 0.2 GPa at 130 K and 1.5 GPa at 160 K. It is found that the relatively strong totally symmetric OH-stretching vibration mode around 3100?cm(-1) exists in the depolarized reduced Raman spectrum χ(VH)(") of the unannealed HDA and that its intensity rapidly decreases by relaxation. The χ(VH)(") profiles of the relaxed HDA are similar to those of liquid water. These results indicate that the HDA reaches a nearly equilibrium state by annealing and the intrinsic state of HDA relates to a liquid state. The pressure-volume curve of the relaxed HDA at 140 K seems to be smooth in the pressure range below 1.5 GPa. 相似文献
43.
Let \(\varOmega \) be a domain in \(\mathbb {R}^{d+1}\) whose boundary is given as a uniform Lipschitz graph \(x_{d+1}=\eta (x)\) for \(x \in \mathbb {R}^d\) . For such a domain, it is known that the Helmholtz decomposition is not always valid in \(L^p(\varOmega )\) except for the energy space \(L^2 (\varOmega )\) . In this paper we show that the Helmholtz decomposition still holds in certain anisotropic spaces which include vector fields decaying slowly in the \(x_{d+1}\) variable. In particular, these classes include some infinite energy vector fields. For the purpose, we develop a new approach based on a factorization of divergence form elliptic operators whose coefficients are independent of one variable. 相似文献
44.
Yasunori Fujikoshi Takashi Kanda Megu Ohtaki 《Annals of the Institute of Statistical Mathematics》1999,51(4):707-721
This paper deals with some inferential problems under an extended growth curve model with several hierarchical within-individuals design matrices. The model includes the one whose mean structure consists of polynomial growth curves with different degrees. First we consider the case when the covariance matrix is unknown positive definite. We derive a LR test for examining the hierarchical structure for within individuals design matrices and a model selection criterion. Next we consider the case when a random coefficients covariance structure is assumed, under certain assumption of between-individual design matrices. Similar inferential problems are also considered. The dental measurement data (see, e.g., Potthoff and Roy (1964, Biometrika, 51, 313-326)) is reexamined, based on extended growth curve models. 相似文献
45.
Norihiro Fukuchi Ye Biqing Yasunori Igasaki Narihiro Yoshida Yuji Kobayashi Tsutomu Hara 《Optical Review》2005,12(5):372-377
We have developed optically-addressed and electrically-addressed liquid crystal spatial phase-only light modulators having
no pixelized structures. We obtained a large depth of phase-only modulation and high diffraction efficiency based on the electro-optical
characteristics of a parallel-aligned nematic liquid crystal. These spatial light modulators (SLM) are of the reflection type,
so there would be a loss of power in the readout light from the half mirror, which was set up so as to separate the incident
and reflected lights. To optimize the characteristics of a reflection type spatial phase-only light modulator, we have proposed
an oblique incident optical readout setup. We have examined the effect of conditions such as the polarization direction and
the incidence angle of the readout light, and the orientation of liquid crystal molecules in the SLM. High diffraction efficiency
close to the theoretical maximum value was obtained by adjusting the above conditions. The simulation analysis can well explain
the experimental results of phase modulation. 相似文献
46.
Matsuoka H Shen JR Kawamori A Nishiyama K Ohba Y Yamauchi S 《Journal of the American Chemical Society》2011,133(12):4655-4660
The oxidation of a redox-active tyrosine residue Y(Z) in photosystem II (PSII) is coupled with proton transfer to a hydrogen-bonded D1-His190 residue. Because of the apparent proximity of Y(Z) to the water-oxidizing complex and its redox activity, it is believed that Y(Z) plays a significant role in water oxidation in PSII. We investigated the g-anisotropy of the tyrosine radical Y(Z)(?) to provide insight into the mechanism of Y(Z)(?) proton-coupled electron transfer in Mn-depleted PSII. The anisotropy was highly resolved by electron paramagnetic resonance spectroscopy at the W-band (94.9 GHz) using PSII single crystals. The g(X)-component along the phenolic C-O bond of Y(Z)(?) was calculated by density functional theory (DFT). It was concluded from the highly resolved g-anisotropy that Y(Z) loses a phenol proton to D1-His190 upon tyrosine oxidation, and D1-His190 redonates the same proton back to Y(Z)(?) upon reduction. 相似文献
47.
Fujiki S Iwao Y Kobayashi M Miyagishima A Itai S 《Chemical & pharmaceutical bulletin》2011,59(5):553-558
It has been reported that tablets of clarithromycin (CAM), a 14-membered macrolide antibiotic, are especially stable under low pH conditions such as in gastric fluid, and showed excellent antibacterial efficiency even though CAM molecules themselves are rapidly decomposed. Therefore, we aimed to clarify the stabilization mechanism of CAM tablets under low pH conditions. From the results of stability and dissolution tests, the optimal decomposition rate constant (K(dec)) and dissolution rate constant (K(dis)) at various pH values were calculated by curve-fitting to consecutive reactions. Consequently, log(K(dec)) increased as pH decreased. On the other hand, log(K(dis)) increased as pH decreased from 3.0 to 1.5, but decreased as pH decreased from 1.5 to 1.0. In addition, the disintegration time of commercially available tablets at pH 1.0 and 1.2 was found to be delayed, resulting in a decrease of K(dis). Furthermore, from powder X-ray diffraction, HPLC and elemental analysis, the delay in disintegration time might be attributable to the formation of a transparent gel, formed by the reaction between CAM molecule and hydrochloric acid under low pH conditions, on the surface of CAM tablet. On the basis of these results, this report can be considered the first case where a transparent gel prevents gastric fluid from penetrating the tablet, resulting in reduced decomposition of CAM following oral administrating. 相似文献
48.
Imoto M Matsui Y Takeda M Tamaki A Taniguchi H Mizuno K Ikeda H 《The Journal of organic chemistry》2011,76(15):6356-6361
Observations show that nitroanilines exhibit an unusually high S(N)Ar reactivity with OH(-) in aqueous media in reactions that produce nitrophenols. S(N)Ar reaction of 4-nitroaniline (2a) in aqueous NaOH for 16 h yields 4-nitrophenol (4a) quantitatively, whereas a similar reaction of 4-nitrochlorobenzene (1a) gave 4a in 2% yield together with recovered 1a in 97%, suggesting that the leaving ability of the NH(2) group far surpasses that of Cl under these conditions. An essential feature of S(N)Ar reactions of nitroanilines is probably that the NH(2) leaving group participates in a hydrogen-bonding interaction with H(2)O. Density functional theory (DFT) calculations for a set of 4-nitroaniline, OH(-), and H(2)O suggest a possible formation of a Meisenheimer complex stabilized by hydrogen-bonding interactions and a six-membered ring structure. The results obtained here contrast with conventional S(N)Ar reactivity profiles in which nitroanilines are nearly unreactive with nucleophiles in organic solvents. 相似文献
49.
Yasunori Maekawa 《Journal of Mathematical Fluid Mechanics》2011,13(4):515-532
We study a linearized operator of the equation for the axisymmetric Burgers vortex which gives a stationary solution to the
three dimensional Navier–Stokes equations with an axisymmetric background straining flow. It is numerically known that the
Burgers vortex obtains better stabilities as the circulation number (or the vortex Reynolds number) is increasing. Although
the global stability of the axisymmetric Burgers vortex is already proved rigorously, mathematical understanding of this numerical
observation has been lacking. In this paper we study a linearized operator that includes the circulation number as a parameter,
and prove that if the operator is restricted on a suitable invariant subspace, then its spectrum moves to the left as the
circulation number goes to infinity. As an application, we show that the axisymmetric Burgers vortex with a high rotation
has a better stability, in the sense that the non-radially symmetric part of solutions to the associated evolution equation
decays faster in time if the circulation number is sufficiently large. 相似文献
50.
Yasunori Fujikoshi Tamio Kan Shin Takahashi Tetsuro Sakurai 《Annals of the Institute of Statistical Mathematics》2011,63(2):387-403
Several criteria, such as CV, C
p
, AIC, CAIC, and MAIC, are used for selecting variables in linear regression models. It might be noted that C
p
has been proposed as an estimator of the expected standardized prediction error, although the target risk function of CV
might be regarded as the expected prediction error R
PE. On the other hand, the target risk function of AIC, CAIC, and MAIC is the expected log-predictive likelihood. In this paper,
we propose a prediction error criterion, PE, which is an estimator of the expected prediction error R
PE. Consequently, it is also a competitor of CV. Results of this study show that PE is an unbiased estimator when the true model
is contained in the full model. The property is shown without the assumption of normality. In fact, PE is demonstrated as
more faithful for its risk function than CV. The prediction error criterion PE is extended to the multivariate case. Furthermore,
using simulations, we examine some peculiarities of all these criteria. 相似文献