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11.
David J. Aitken Dominique Guillaume Henri-Philippe Husson Angle Chiaroni Claude Riche 《Journal of heterocyclic chemistry》1991,28(3):705-709
The title compound, containing a new heterocyclic skeleton, was identified by X-ray crystallography as the product of condensation of (R)-phenylglycinol with an excess of formaldehyde. The molecule adopts a rigid double twist-chair conformation in both solid and solution states. 相似文献
12.
Yoshinori Kamiya Keishin Mizoguchi Yasutoshi Naito Dominique Bourbon 《Journal of Polymer Science.Polymer Physics》1991,29(2):225-234
Sorption and dilation isotherms for argon in poly(ethyl methacrylate) (PEMA) are reported for pressures up to 50 atm over the temperature range 5–85°C. At temperatures below the glass transition (Tg=61°C), sorption isotherms are well described by the dual-mode sorption model; and isotherms above Tg follow Henry's law. However, isotherms for dilation due to sorption are linear in pressure at all temperatures over the range investigated. Partial molar volumes of Ar in PEMA are obtained from these isotherms. The volumes are approximately constant above Tg (about 40 cm3/mol), whereas the volumes below Tg are smaller and dependent on both temperature and concentration (19–26 cm3/mol). By analyzing the experimental data according to the dual-mode sorption and dilation model, the volume occupied by a dissolved Ar molecule and the mean size of microvoid in the glass are estimated to be 67 129 Å3, respectively. The cohesive energy density of the polymer is also estimated as 61 cal/cm3 from the temperature dependence of the dual-mode parameters. 相似文献
13.
Dominique Simpelaere 《Chaos, solitons, and fractals》1994,4(12):2223-2235
We compute the correlation dimension of a measure defined on a general Sierpinski carpet. We relate this function to a free energy function associated to a partition composed of ‘nearly squares’ and well fitted to the planar Cantor set. Actually, we prove that these functions are real analytic on
, are strictly increasing and are strictly concave (respectively linear in the degenerate case). This is an example of a two-dimensional dynamical system contracting in the two directions with different ratios. We first study measures of Gibbsian type before generalizing to Markovian measures. 相似文献
14.
Dominique Hulin 《Geometriae Dedicata》2007,130(1):109-136
La condition pour qu’il existe des n-gones de Poncelet, inscrits dans un cercle, et circonscrits à un autre cercle, est polynomiale en les paramètres définissant ces deux cercles. Nous décomposons ces polynômes “de Poncelet” en facteurs irréductibles que nous interprétons géométriquement. 相似文献
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16.
Dominique Tourns 《Historia Mathematica》2003,30(4):457
In the period which precedes the appearance of computers, needs in calculation of the scientists and engineers led to an important development of graphic methods of integration. To contribute to the study of this little known phenomenon, the article presents techniques and instruments used for the graphic integration of ordinary differential equations, and looks for their historic origins by going back to the beginning of calculus: processes of geometric calculation by the polygonal method or the method of radius of curvature, use of tractional motion for the conception of integraphs, reduction to graphic quadratures in finite or infinite number. 相似文献
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18.
Nicholas I. M. Gould Dominique Orban Annick Sartenaer Phillipe L. Toint 《4OR: A Quarterly Journal of Operations Research》2005,3(3):227-241
In this paper, we examine the sensitivity of trust-region algorithms on the parameters related to the step acceptance and
update of the trust region. We show, in the context of unconstrained programming, that the numerical efficiency of these algorithms
can easily be improved by choosing appropriate parameters. Recommended ranges of values for these parameters are exhibited
on the basis of extensive numerical tests.
MSC classification:
65K05, 90C26, 90C30 相似文献
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20.
Dominique Margelin Anny Fourtanier Thierry Thevenin Chantal Medaisko Monique Breton Jacques Picard 《Photochemistry and photobiology》1993,58(2):211-218
Abstract— The effect of UVB exposure on the distribution and synthesis of dermal proteoglycans was measured in the skin of hairless mice. Two groups of mice were included: one was irradiated for 10 weeks; the other was kept as control. After intraperitoneal injection of sodium 35 S-sulfate, punch biopsies were taken for histology and proteoglycans were extracted from the remaining skin with 4 M guanidinium chloride, containing 3–[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (0.5%, weight per volume). Following proteolytic digestion, the glycosaminoglycan constituents were isolated and analyzed by quantitative cellulose acetate electrophoresis and enzymatic digestibility.
Under the influence of UVB radiation, newly synthesized proteoglycans measured by35 SO4 uptake increased as much as 60%. In addition, the irradiated skin had a higher average content of proteoglycan than had control skin (4981 μg vs 4134 μg/g dry weight). This could be ascribed to an increase in heparin (1400 vs 533 μ g/g dry weight) and heparan sulfate (472 vs 367 μg/g dry weight), whereas no change in the concentration of hyaluronic acid (1243 vs 1372 μg/g dry weight) and dermatan sulfate (1866 vs 1863 μg/g dry weight) was observed. The irradiated animals also exhibited a marked increase in the synthesis of heparan sulfate and heparin (62% and 71%, respectively). These results demonstrate that chronic doses of UVB altered proteoglycan metabolism through both quantitative and qualitative changes. 相似文献
Under the influence of UVB radiation, newly synthesized proteoglycans measured by