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101.
Polymethylphenylsilane (PMPS) was modified by chloromethylation then condensed with Na salt of Disperse Red 1(DR1). The product, DR1 functionlized PMPS(PMPS-DRD, was thoroughly washed until it had no DRl or other dopant. Its glass transition temperature is 155℃, contains 4.5% weight of DRl residue. The UV-Vis spectrum of PMPS-DRl shows a broad ab-sorption band in the range 400-700 nm. Photoconductivity measured on a 2 μm film made of PMPS-DR1, using a 632.8 nm He-Ne laser beam, shows that it is electric field dependent and in the range of 10-13 to 10-11S/cm. The electro-optical coefficient of PMPS-DRl was measured as a value of r33=0.8 pm/V. 相似文献
102.
103.
Let a normed space X possess a tiling T consisting of unit balls. We show that any packing P of X obtained by a small perturbation of T is completely translatively saturated; that is, one cannot replace finitely many elements of P by a larger number of unit balls such that the resulting arrangement is still a packing.In contrast with that, given a tiling T of Rn with images of a convex body C under Euclidean isometries, there may exist packings P consisting of isometric images of C obtained from T by arbitrarily small perturbations which are no longer completely saturated. This means that there exists some positive integer k such that one can replace k−1 members of P by k isometric copies of C without violating the packing property. However, we quantify a tradeoff between the size of the perturbation and the minimal k such that the above phenomenon occurs.Analogous results are obtained for coverings. 相似文献
104.
105.
Huang JR 《The European physical journal. E, Soft matter》2006,19(4):399-412
A new model is proposed to explain coiling of myelins composed of fluid bilayers. This model allows the constituent bilayer
cylinders of a myelin to be non-coaxial and the bilayer lateral tension to vary from bilayer to bilayer. The calculations
show that a myelin would bend or coil to lower its free energy when the bilayer lateral tension is sufficiently large. From
a mechanical point of view, the proposed coiling mechanism is analogous to the classical Euler buckling of a thin elastic
rod under axial compression. The analysis of a simple two-bilayer case suggests that a bilayer lateral tension of about 1
dyne/cm can easily induce coiling of myelins of typical lipid bilayers. This model signifies the importance of bilayer lateral
tension in determining the morphology of myelinic structures. 相似文献
106.
Blue phosphors Ca1 − xAl2O4: xEu2+ were prepared by high temperature solid-state method. Their structure, morphology and luminescent properties were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and fluorescence spectroscopy. The effect of different amounts of fluxing agent H3BO3 on structure, morphology and luminescent properties of blue phosphors Ca1 − xAl2O4: xEu2+ luminous intensity caused by different amount of H3BO3 was also investigated. The amount of H3BO3 doped Ca1 − xAl2O4: xEu2+ in optimal luminous intensity had been determined. The results showed that both the excitation and emission spectra of samples were all broad bands, and that the peak of emission spectra was near 442 nm, which was corresponding to the 4f65d → 4f7 transition of Eu2+ illuminating blue light. Ca1 − xAl2O4: xEu2+ (x = 3.5 mol%) could be gained with good morphology and the best luminous intensity when H3BO3 mass ratio was 0.5 wt%. 相似文献
107.
研究无封胶白光数码管衰减机理,利用蓝白比拟法测算无封胶白光数码管荧光粉转换率.对蓝白数码管分3组进行电流老化实验,老化电流分别为20、40mA和60mA.在恒定直流为20mA,老化时间为1000h实验中,通过分析蓝、白数码管光谱曲线的变化,研究了蓝光光输出功率和黄光光输出功率衰减情况,利用实验数据,分析表明了荧光粉转换率的衰减是影响无封胶白光数码管老化的重要因素.同时分析比较了在40mA和60mA不同电流老化实验下得到的荧光粉转换率,发现工作电流越大,荧光粉转化率衰减越快,符合无封胶白光数码管在大电流作用下衰减更快的实际情况,影响使用寿命.对荧光粉转换率的研究将为无封胶白光数码管的应用及进一步研究无封胶白光数码管衰减原因提供参考. 相似文献
108.
Motivated by numerous X-ray scattering studies of lamellar phases with membrane proteins, amphiphilic peptides, polymers,
or other inclusions, we have determined the modifications of the classical Caillé law for a smectic phase as a function of
the nature and concentration of inclusions added to it. Besides a fundamental interest on the behavior of fluctuating systems
with inclusions, a precise characterization of the action of a given protein on a lipid membrane (anchoring, swelling, stiffening
...) is of direct biological interest and could be probed by way of X-ray measurements. As a first step we consider three
different couplings involving local pinching (or swelling), stiffening or curvature of the membrane. In the first two cases
we predict that independent inclusions induce a simple renormalization of the bending and compression moduli of the smectic
phase. The X-ray experiments may also be used to probe correlations between inclusions. Finally we show that asymmetric coupling
(such as a local curvature of the membrane) results in a modification of the usual Caillé law.
Received 10 March 2000 and Received in final form 30 August 2000 相似文献
109.
We predict the elastic properties of mixed amphiphilic monolayers in the swollen state within the blob model using scaling
arguments. First the elastic moduli and the spontaneous curvature of a bimodal brush are determined as a function of the composition
and the relative chain length. We obtain simple and useful scaling functions which interpolate between the elastic moduli
of a pure short-chain brush and a pure long-chain brush. By using the analogy between block copolymer interfaces and polymeric
brushes, the effect of mixing on self-assembled diblock copolymer monolayers is investigated in the swollen state. We calculate
various interfacial properties, such as the equilibrium surface coverage, interface curvature, and the mixing free energy
as a function of the composition. In general, we find a nonlinear dependence on the composition, which deviates from the simple
linear averaging of the properties of pure components. Our results are used to discuss a recent experiment on the effect of
amphiphilic block copolymers on the efficiency of microemulsions.
Received 29 December 2000 and Received in final form 19 March 2001 相似文献
110.
Padmarajiah Nagaraja Mohammed Fawaz Silwadi Akheel Ahmed Syed 《Mikrochimica acta》2000,135(3-4):185-189
A new, simple, and sensitive spectrophotometric method for the determination of certain tricyclic antidepressants, belonging
to the dibenzazepine class of drugs, has been developed. The proposed method is based on the reaction of imipramine hydrochloride
(IPH), desipramine hydrochloride (DPH), clomipramine hydrochloride (CPH), trimipramine maleate (TPM) or opipramol (OPP) with
iron(III), and subsequent reaction with ferricyanide in an acetic acid medium, to yield a blue product, with maximum absorption
at 720–730 nm.
Received January 24, 2000 相似文献