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101.
We present a study on the fluctuations of semiflexible actin filaments using fluorescence videomicroscopy, focusing on the end-to-end fluctuations of single filaments. In order to specifically measure the position of the polymer's ends, we developed a novel noninvasive method that consists of annealing short end tags to the filaments. This allows us to probe polymer fluctuations to a very high accuracy. We compared the distribution of the end-to-end distance with recent theoretical results, and found excellent agreement. We also studied the dynamics of the mean-square end-to-end distance deltaR2(t) and orientation of the ends, deltaTheta(2)(t), finding power laws t(3/4) and t(1/4), respectively. Scaling behavior for deltaR2(t) is observed over several decades in relaxation time in agreement with theoretical results. 相似文献
102.
We investigated the condition of unique self-written channel and multichannel propagation inside bulk photopolymerizable materials. Light was introduced in the medium by a single-mode optical fiber. At a very low beam power of 5 muW , a unique uniform-channel waveguide without any broadening was obtained by polymerization. When the input power is increased to 100 muW , the guide becomes chaotic and multichannel. We connected two fibers separated by a 1-cm distance. The results open the door to studies of the optical and electro-optical properties of photopolymerized guides doped by nonlinear optical chromophores and to possible applications in integrated optical devices. 相似文献
103.
Aït Hmaïdouch L. Mançour Billah S. El Hadek M. Coffy G. 《Journal of Thermal Analysis and Calorimetry》2000,61(1):165-171
The solid-liquid equilibria of the ternary system H2 O-Al(NO3 )3 -Mg(NO3 )2 were studied at 15, 25, 30, 40 and 50°C by using a synthetic method which allows to determine all the characteristic points
of isothermal sections. In all isotherms the liquidus exhibit two curves corresponding to the saturation in Mg(NO3 )2 ⋅6H2 O and Al(NO3 )3 ⋅9H2 O. Neither double salts nor mixed crystals are observed in the temperature and composition field studied.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
104.
Cia D Bonhomme B Azim M Wada A Doly M Azaïs-Braesco W 《Journal of chromatography. A》1999,864(2):257-262
A high-performance liquid chromatographic (HPLC) procedure was developed to separate all-trans-, 13-cis-, 11-cis- and 9-cis-retinal isomers. Two reversed-phase Vydac C18 columns in series were used with an isocratic solvent system of 0.1 M ammonium acetate-acetonitrile (40:60, v/v) as mobile phase and all-trans-9-(4-methoxy-2,3,6-trimethylphenyl)-3,7-dimethyl-2,4,6,8-no natetraene-1-ol (TMMP) as internal standard. Prior to HPLC, the retinal isomers were efficiently extracted in their original isomeric conformation using dichloromethane-n-hexane in the presence of formaldehyde. This technique is suitable for the assay of 11-cis- and all-trans-retinal isomers in retina. 相似文献
105.
Loïc Colson 《BIT Numerical Mathematics》1992,32(1):5-9
We present a primitive recursive programinf_with_lists computing the minimum of two natural numbersn andp (written in unary notation) and using primitive recursion on lists. This program has at first sight the required property of visiting simultaneously its inputs, so it is a counterexample to a theorem showing that such a program cannot be written in the language of primitive recursion on natural numbers, in the more general framework of primitive recursion on term algebras. However, its complexity is at leastinf(n,p)2 so it does not implement the algorithm we have in mind to computeinf(n,p). 相似文献
106.
R. Coïsson 《Optics Communications》1977,22(2):135-137
We study the conditions in which a charged particle in an inhomogeneous magnetic field (particularly at the edges of a “long” uniform magnet or in a “short” magnet) can emit synchrotron radiation with a spectrum extending beyond the “critical frequency”. We suggest that this effect should be clearly visible (and also useful) in the case of very high energy proton storage rings. 相似文献
107.
Pumping of liquids using two-phase flow has been examined experimentally in small air-lift pumps with 12—19 mm bore plexiglass tubes. An air injection system was devised to create and maintain ‘perfect’ slug flow in the vertical riser tube. An equation has been derived, based on momentum conservation considerations, which correlates well with the measurements obtained. Slip variation, or liuid holdup, between the two phases and the formation of the ‘entrance’ section part of the pump (suction pipe) were taken into consideration. Unlike its predecessors, this equation predicts the reversal in the pump performance curve observed experimentally. 相似文献
108.
Lejeune C Coelho C Bonhomme-Coury L Azaïs T Maquet J Bonhomme C 《Solid state nuclear magnetic resonance》2005,27(4):242-246
We show that it is possible to efficiently transfer magnetization from 31P to 29Si, using variable amplitude CP MAS experiment. This experiment is demonstrated by using Si5O(PO4)6, the synthesis protocol of which is described. From the obtained results, we show that the experiment allows the spectral edition of 29Si spectra from 31P→29Si CP, enabling the studies of derivatives involving Si–O–P linkages, such as phosphosilicate glasses, microporous silicoaluminophosphates (SAPO) and bioactive phosphosilicates. 相似文献
109.
Alkanes deposited on aqueous substrates exhibit two different types of wetting behavior: alternatively to the usual first-order wetting transition, a sequential-wetting scenario of a long-range critical wetting transition preceded by a first-order thin-thick transition may be observed. Here, we present the first successful experimental attempt to locate the transition point between the standard first-order wetting and the long-range critical wetting: a critical end point, observed in a mixture of pentane and hexane which is deposited on an aqueous solution of glucose. Furthermore, we present the first direct measurement of the contact angle in the intermediate wetting state (frustrated-complete wetting) in the sequential-wetting scenario of hexane on brine and compare to theoretical predictions. 相似文献
110.