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131.
Abstract

Scanning confocal microscopy was used for contact angle measurement of individual microspheres. The measurements were carried out by using different laser‐scanned layers of the particle floating on the air–water interface. The ratio of the diameter for the cross‐section of the protruded area of the particle at the air–water interface to the actual diameter of the particle is used for contact angle measurements. Two systems, i.e., glass and polystyrene microspheres with diameters of 3–10 and 6 µm, respectively, with water were used for this investigation (this size range of particles are most relevant to inhalation applications). Using the developed methodology, contact angles of 27° and 41° were measured (with water) for glass and polystyrene particles, respectively. The theoretical error in contact angle measurement for the developed methodology is determined to be generally about 1° with a maximum of 3° for contact angle of particles ranging from 2 to 24 µm in size; the experimental error was 4–6°. The contact angles of glass and polystyrene particles were compared to those obtained from pendant drop method and confirmed.  相似文献   
132.
The effect of octadecanol on dilational properties of 4,5-diheptyl-2-propylbenzene sulfonate and partly hydrolyzed polyacrylamide at the decane-water interface has been examined by means of longitudinal method. The octadecanol plays different roles in influencing the structure of adsorbed layers at different bulk concentration. A small quantity of octadecanol may enhance the dilational modulus by forming densely packed mixed-adsorption layer with surfactant molecules through hydrophobic interaction, which leads to the increase of dilational modulus. However, due to the weakening of the “entanglement” among long alkyl chains in surfactant molecules by the intercalation of octadecanol, the superfluous addition of octadecanol could decrease the dilational modulus. In the case of polymer/octadecanol system, the addition of the polymer may enhance the dilational modulus due to the slow diffusion-exchange process of the polymer.  相似文献   
133.
Clay particles with adsorbed asphaltenes, which are commonly found in produced water, have been used as seed particles during precipitation of calcium carbonate in order to determine whether such particles may influence the kinetics of precipitation. The results show that the presence of the adsorbed asphaltenes accelerates the precipitation, and there is also a significant difference between different types of adsorbed asphaltenes. The adsorption of asphaltenes at the seed surface leads to a significant increase in the interfacial tension between the seed surface and the aqueous solution, and calcium carbonate therefore precipitates at the seed surface in order to reduce this high interfacial tension.  相似文献   
134.
Small‐angle neutron scattering from magneto‐vesicles (MVs) prepared by extrusion was studied. Contrast variation allowed the determination of structure and sizes of the vesicles and the encapsulated magnetic nanoparticles, respectively. The results from MVs synthesized with a 0.3% volume fraction of citrate‐coated magnetic nanoparticles are compared to those of similarly prepared vesicles of the neutral lipid 1,2‐Dioleoyl‐sn‐Glycero‐3‐Phosphocholine (DOPC) (without magnetic particles), and magnetic particles not encapsulated in vesicles. It is observed that the bilayers of the as‐prepared MVs, and the encapsulated nanoparticles retain their structural properties, highlighting the suitability of the MVs for applications.  相似文献   
135.
A model is presented to provide quantitative measures to estimate the trends of the change in the penetration of the added component into the polar part of the amphiphile layer in lamellar liquid crystals of water and ethoxylated surfactants with added water (or polar solvents). The total thickness of the bi‐layer is treated as composed of an aqueous layer, of a layer of the polar groups from the surfactant and of the hydrocarbon chains of the latter. A fraction α of the added water is assumed penetrating the polar group layer leading to its expansion. The evaluation is built on the fact that experimental determinations of the interlayer spacing in the overwhelming majority of cases show a first order linear dependence on the ratio of added water. In the model this linearity is obtained by variation of the degree of penetration of water. The model indicated a reduction in the degree of penetration with added water, which is a rational trend. The model demonstrates the earlier interpretation of a structure, whose interlayer spacing is invariant with water contents as nonswelling; for example, in which all added water penetrates the amhiphile layer, is not appropriate. The model demonstrates the constancy of the interlayer spacing to be a consequence of a balance between the expansion of the amphiphile layer and the increase of a “free water” layer.  相似文献   
136.
A polymer-stabilised blue-phase liquid crystal display (PSBP-LCD) with double-side in-plane switching (DS-IPS) electrode structure is proposed. This structure shows the transflective characteristics because the bottom electrodes are made by aluminium material. For transflective displays, it exhibits a well-matched voltage-dependent transmission and reflection curves through designing the width and gap of the top electrodes. When a bias voltage is applied on the top electrodes, it exhibits as a good viewing angle controllable display.  相似文献   
137.
The dynamic and conformational behaviour of four mesogenic resorcinarenes exhibiting columnar mesophases have been studied by a combination of broadband dielectric spectroscopy and deuterium solid state NMR. Broadband dielectric spectroscopy provided evidence for two relaxation processes present both in the mesophase and in the isotropic liquid. The high frequency process II, common to all mesogens, has been assigned to the libration of the carbonyl groups of the ester junctions between the core and the side chains. The low frequency process I, present in conformationally mobile mesogens 1 and 2, has been attributed to the ring inversion process of the macrocyclic core associated with dipole inversion along the columnar axis. Deuterium solid state NMR performed on 4, the deuteriated analogue of 1, confirmed the molecular dynamics attribution for process I, assigning the ring inversion to the interconversion of the two equivalent crown conformations.  相似文献   
138.
The fluorinated compound, (S)-4′′-(6-perfluoropentanoyoxyhexyl-1-oxy)-2′,3′-difluoro-4-(1-methylheptyloxycarbonyl)-[1,1′:4′,1′′]-terphenyl, which exhibits antiferroelectric SmCA*, ferroelectric SmC* and paraelectric SmA* phases, has been investigated by polarising optical microscopy, differential scanning calorimetry, X-ray diffraction and frequency-dependent dielectric spectroscopy methods. X-ray studies have revealed that the layer thickness remains almost constant in the SmA* phase but within the SmC* and SmCA* phases it decreases with decreasing temperature, a step jump being observed only at the SmA*–SmC* transition. The tilt angle in the SmCA* phase decreases from 22.2° to 19.5°, and in the SmC* phase it decreases from 18.8° to 5.5°. Spontaneous polarisation is found to be quite high and varies between 74.1 and 118.7 nC cm?2. The variation in ε′ and ε′′ with temperature shows a discontinuous change at the transition temperatures. Goldstone mode relaxation is only observed in the ferroelectric and antiferroelectric phases and is found to be of the Cole–Cole type. The soft mode is observed on application of a bias field near the SmC*–SmA* transition. Neither the soft mode nor the anti-phase azimuthal angle fluctuation mode is observed in SmCA*. Rotational viscosity decreases quite rapidly with temperature but in a different manner in the ferroelectric and antiferroelectric phases. Activation energy for this process is found to be 48.14 kJ mol?1 in the SmC* phase.  相似文献   
139.
利用表面引发原子转移自由基聚合(SI-ATRP)在聚对苯二甲酸乙二醇酯(PET)薄膜表面接枝苯乙烯和4-氟苯乙烯的共聚物.研究不同反应时间和不同配比下接枝共聚物对聚酯薄膜表面组成、结构和性能的影响.通过傅利叶变换红外光谱仪(ATR/FTIR),X-射线光电子能谱仪(XPS),凝胶渗透色谱(GPC)和扫描电子显微镜(SEM)对接枝改性前后PET薄膜的表面组成,结构和形貌进行分析;利用接触角测试和表面能计算对比研究接枝改性前后PET薄膜的表面性能.结果表明反应时间和单体百分含量对接枝百分率及接触角有一定的影响,随着反应时间的增长,聚酯薄膜表面接枝百分率增大,接触角增加,表面自由能下降.  相似文献   
140.
Describes the functions, background applications and features of the resolver, in order to calculate the angle position of the resolver signals, this paper choose AD7656 precision chip, proposed the resolver algorithm for calculating resolver angle by measuring the output voltage and excitation voltage of the resolver. Mainly introduce AD7656 and its hardware circuit design, and flowchart of the algorithm for arctangent. This algorithm is simple and reliable. Experimental results show that the system design is reasonable, measurement algorithms of resolver angle meets the requirements. Analyze the error for this result and prepare for the study.  相似文献   
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