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21.
Katarzyna Kaszyńska Ewa Banachowicz Genowefa Ślósarek Adrian Morawiec Iwona Gawrońska Jan Barciszewski 《Journal of solution chemistry》2002,31(12):987-993
We analyze the structure of napin (BngNAP1), a storage protein (m.w. 14.5 kDa) from Brassica napus. On the basis of the results of 1H NMR spectroscopy and dynamic light scattering (DLS) studies, the overall shape and secondary structure of the molecule are estimated. 相似文献
22.
The effect of a weak convective heat transfer on the thermocapillary interaction of two bubbles with an arbitrary orientation relative to an externally imposed temperature gradient is examined. Asymptotic analysis of the case of large separation distances, Z, suggests that the corrections to the bubbles' velocities are of
(Pe/Z2), rather than
(Pe2) previously found for an isolated bubble. Equal-sized bubbles are known to move with the same velocities, as if they were isolated, when heat conduction is the only transport mechanism. However, the convective transport results in a relative motion of the bubbles. The tendency of equal bubbles to line up in a plane perpendicular to the applied thermal gradient is shown analytically in the weakly nonlinear limit of small Pe numbers, and an interesting interaction behavior in the case of unequal bubbles is discussed. 相似文献
23.
P. Cinquina D. Cam E. Tampellini L. L. Chapoy 《Journal of Polymer Science.Polymer Physics》1993,31(12):1809-1817
Solution characterization of the thermotropic liquid–crystalline copolyester synthesized from terephthalic acid, phenyl hydroquinone, and (1-phenylethyl) hydroquinone (2 : 1 : 1) has been performed. Viscometry, size exclusion chromatography, and light scattering have been carried out under the optimal conditions found for measurement: 85°C in a 50/50 mixture by weight of phenol/1,2,4-trichlorobenzene. The absolute weight-average molecular weight from light-scattering measurements served for calibration of indirect methods of charac-terization (e.g., the limiting viscosity number [η] is related to the molecular weight by [η] = 5.10 × 10?4 Mw0.72), and the molecular weight per unit chain length, $ \bar M_L * $, from light scattering and size exclusion chromatography (SEC) is found to be 28 Å?1, consistent with theoretical expectations. The calculated persistence length q is 28 Å. Moreover, the meth-odology of SEC characterization enables the kinetics of solid-state postpolymerization of this liquid-crystalline copolyester to be studied. © 1993 John Wiley & Sons, Inc. 相似文献
24.
25.
This paper is concerned with nonisentropic hydrodynamic models for two-carrier plasmas, which take the form of Euler equations for conservation laws of mass density, current density and energy density for two-carrier plasmas, coupled to Poisson’s equation for self-consistent electronic field. Due to the nonlinear coupling and cancellation between electrons and ions, the expected dissipation rates of densities for two carriers are no longer available in comparison with the one-carrier case, which leads to the lack of exponential stability near constant equilibrium in the whole space. In order to capture the weaker dissipation and obtain global solutions in spatially critical Besov spaces, calculus techniques which have been recently developed in Chemin–Lerner spaces, will be further applied. 相似文献
26.
《Journal of Dispersion Science and Technology》2013,34(5):585-592
Abstract This article discusses the like‐charge attraction of colloidal spheres close to a charged plate and compares results produced by an electrostatic and a hydrodynamic model with experimental data. Hydrodynamic coupling is shown to be the dominating effect, while the electrostatic influence may often be neglected. Some observations, however, can be explained only by means of a combined electrostatic–hydrodynamic model, which is derived in this work. The combined model is able to predict not only the attractive force between particles of similar charge close to a charged plate but also the change to a purely repulsive force once the sphere‐plate distance is further reduced. This prediction matches qualitatively results of experiments reported in the literature. 相似文献
27.
Due to the complexity of compressible flows, nonlinear hydrodynamic stability theories in supersonic boundary layers are not sufficient. In order to reveal the nonlinear interaction mechanisms of the rapidly amplified 3-D disturbances in supersonic boundary layers at high Mach numbers, the nonlinear evolutions of different disturbances in flat-plate boundary layers at Mach number 4.5, 6 and 8 are analyzed by numerical simulations. It can be concluded that the 3-D disturbances are amplified rapidly when the amplitude of the 2-D disturbance reaches a certain level. The most rapidly amplified 3-D disturbances are Klebanoff type (K-type) disturbances which have the same frequency as the 2-D disturbance. Among these K-type 3-D disturbances, the disturbances located at the junction of upper branch and lower branch of the neutral curve are amplified higher. Through analyzing the relationship between the amplification rate and the spanwise wavenumber of the 3-D disturbances at different evolution stages, the mechanism of the spanwise wavenumber selectivity of K-type 3-D disturbances in the presence of a finite amplitude 2-D disturbance is explained. 相似文献
28.
发动机是军舰上的重要部件之一,其稳定性对军舰的正常航行具有重要影响。以舰用发动机关键部件(主泵轴承)为具体研究对象,提出了基于功率谱包络能量和支持向量机相结合的故障诊断方法。首先获取了大量可表征舰用发动机主泵轴承健康状态的振动加速度信息,对其进行功率谱分析,获得其功率谱的包络能量;以获取的舰用发动机主泵轴承功率谱的包络能量构建特征向量,并设计基于SVM的舰用发动机主泵轴承故障诊断模型,对主泵轴承的故障进行诊断研究。研究结果表明,采用基于功率谱包络能量和SVM相结合的舰用发动机关键部件故障诊断方法,可以很好实现主泵轴承的故障诊断效能,为舰用发动机主泵轴承故障诊断的工程应用奠定了基础。 相似文献
29.
Björn Johansson Prof. Fredrik Höök Prof. David Klenerman Dr. Peter Jönsson 《Chemphyschem》2014,15(3):486-491
An important and characteristic property of a cell membrane is the lateral mobility of protein molecules in the lipid bilayer. This has conventionally been measured by labeling the molecules with fluorescent markers and monitoring their mobility by different fluorescence‐based techniques. However, adding the label to the studied molecule may affect the system, so it is an assumption in almost all experiments that the measured mobility of the biomolecule with its label is the same as that of the unlabeled molecule. However, this assumption is rarely tested due to a lack of suitable methods. In this work, a new technique to perform label‐free diffusivity measurements is developed and used to measure the effect of the label for two common protein–lipid systems: 1) streptavidin (SA) coupled to a supported lipid bilayer (SLB) through biotinylated lipids and 2) the extracellular part of the T‐cell adhesion protein CD2, coupled to an SLB through histidine tags to nickel‐chelating lipids. A measurable (≈12 %) decrease in diffusivity is found for both labeled proteins, even though the molecular mass of the label is almost 100 times smaller than those of the proteins (≈50 kDa). The results illustrate the importance of being able to study different biophysical properties of cell membranes and their mimics without relying on fluorescent labels, especially if fluorescent labeling is difficult or is expected to affect the nature of the intermolecular interactions being studied. 相似文献
30.
Dr. Alessandro Presentato Dr. Antonino Scurria Dr. Lorenzo Albanese Dr. Claudia Lino Dr. Marzia Sciortino Dr. Mario Pagliaro Dr. Federica Zabini Dr. Francesco Meneguzzo Prof. Rosa Alduina Dr. Domenico Nuzzo Dr. Rosaria Ciriminna 《ChemistryOpen》2020,9(5):628-630
Pectin extracted via hydrodynamic cavitation in water only from waste lemon peel and further isolated via freeze drying displays significant antibacterial activity against Staphylococcus aureus, a Gram positive pathogen which easily contaminates food. The antibacterial effect of the new IntegroPectin is largely superior to that of commercial citrus pectin, opening the way to advanced applications of a new bioproduct now obtainable in large amounts and at low cost from citrus juice industry's waste. 相似文献