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排序方式: 共有265条查询结果,搜索用时 93 毫秒
111.
112.
Abstract Polymer dispersed liquid crystal thin films have been deposited on glass substrates by the processes of polymerization and solvent evaporation induced phase separation. The electron and the optical polarization microscopies of the films reveal that PDLC microdroplets formed during the process of phase separation near the top surface of the film remain exposed and respond to shear stress due to air or gas flow on the surface. Optical response of the film to an air flow-induced shear stress input on the free surface has been measured. Director orientation in the droplets changes with the applied shear stress leading to time varying transmitted light intensity. Director dynamics of the droplet for an applied step shear stress has been discussed from free energy considerations. Results on the measurement of light transmission as a function of the gas flow parameter unambiguously demonstrate the potential of these systems for use as boundary layer and gas flow sensors. 相似文献
113.
In a wide search program for new and efficient antimicrobial agents, a series of oxadiazole/azetidinone-incorporated benzimidazoles have been synthesized and evaluated against different Gram-positive and Gram-negative bacteria. Derivatives having long alkyl chain on the oxadiazole/azetidinone moiety with three or more carbon atoms have shown less antibacterial activity. 相似文献
114.
115.
A simple, selective, rapid, and economical reversed phase high performance liquid chromatography(RP-HPLC) method for the determination of doxofylline in the commercial dosage form has been developed and validated. The separation
and quantification were achieved on an HiQ Sil C 18 W column using a mobile phase of acetonitrile: buffer (50: 50), pH 3,
at a flow rate of 1 mL/min with detection of analyte at 272 nm. The separation was achieved within 3.1 ± 0.3 min for doxofylline
sample. The method showed good linearity in the range of 10–80 μg/mL. The intra and inter day RSD ranged from 0.37–0.53%.
The recovery (mean ± S.D.) of low, middle and high concentrations were 100.04 ± 0.80, 100.01 ± 0.20, 100.07 ± 0.30 respectively.
Limit of detection and limit of quantification were 0.03 and 0.1 μg/mL, respectively. 相似文献
116.
Ravi Mosurkal Lynne A. Samuelson Kenneth D. Smith Phillip R. Westmoreland Virinder S. Parmar Fadong Yan 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11):942-946
Composites of titanium dioxide (TiO2) nanoparticles and biocatalytically synthesized dimethylsiloxane copolyamides were prepared, and their thermal and flame-retardant properties were investigated. The flammability properties such as heat release capacity and total heat release were measured from microscale cumbustion calorimetry (MCC). The thermal degradation temperatures, char yields, and the heat-release capacities of these nanocomposites were significantly improved over the pure polymers. The heat-release capacities of the siloxane copolymer nanocomposites with 20wt% of TiO2 were found to be 167 and 129 J/g K, which is a 35% less than the pure polymers (260 and 194 J/g K, respectively). The SEM/EDAX surface-analysis studies on nanocomposite films and their char revealed that nanocrystalline-TiO2 plays an important role in forming carbonaceous silicate char on the surface as a protective layer. 相似文献
117.
A series of metal complexes of Zn(II) and Hg(II) having the general composition [ML2]X2 with thiosemicarbazide have been prepared and characterized by elemental chemical analysis, molar conductance, and spectral
(IR and mass) studies. The IR spectral data suggest the involvement of sulfur and terminal amino nitrogen in coordination
to central metal ion. On the basis of spectral studies, a tetrahedral geometry has been assigned for the Zn(II) and Hg(II)
complexes. Thiosemicarbazide and its metal complexes have been tested in vitro against a number of microorganisms in order
to assess their antimicrobial properties.
The article is published in the original. 相似文献
118.
A series of metal complexes of cobalt(II), nickel(II), and copper(II) having the general composition [M(L)2X2] with thioacetamide have been prepared and characterized by elemental chemical analysis, molar conductance, magnetic susceptibility
measurements, mass, IR, EPR, and electronic spectral studies. The IR spectral data suggests the involvement of sulfur and
amino nitrogen in coordination to central metal ion. On the basis of spectral studies, an octahedral geometry has been assigned
for the cobalt(II) and nickel(II) complexes whereas tetragonal geometry for copper(II) complexes. Thioacetamide and its metal
complexes have been tested in vitro against a number of microorganisms in order to assess their antimicrobial properties. 相似文献
119.
Rayaprol S. Parmar Rohini Kuberkar D. G. Chakraborty Keka R. Krishna P. S. R. Ramanadham M. 《Pramana》2004,63(2):213-219
Structural studies on Dy-substituted La-2125 type superconductors have been carried out by neutron diffraction experiments at room temperature using a monochromatic neutron beam of wavelength (λ) = 1.249 Å. A series of samples with La2-xDyxCa2xBa2Cu4+2xOz stoichiometric composition, forx = 0.1–0.5, have been studied for their structural properties. A tetragonal Y-123 unit cell was taken as the starting model for the Rietveld analysis. All the samples fit into the starting model, with no structural transition taking place with increasing dopant concentration. The results of Rietveld analysis and structural properties will be discussed in detail.
相似文献120.