Materials Literature
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The curing of liquid crystalline (LC) epoxides containing phenyl benzoate mesogens was studied under applied ac electric fields. When curing reactions began under a low-frequency electric field (∼1 V/μm), parallel molecular orientation slowly changed to perpendicular to the field, because a crossover (cutoff) frequenc…
An experimental investigation was carried out to measure transgranular stress corrosion crack growth rates (CGR) in precracked X-60 steel specimens exposed to neutral (pH 7) dilute simulated ground water (designated NS4) while being cyclically loaded in cantilever bending. Testing was carried out over short-term (gene…
Efficient preparation of thin films has been achieved with a high-density ablation plasma produced by the interaction of an intense, pulsed ion beam with solid targets, a process called ion beam evaporation, having an instantaneous deposition rate of cm/s. In addition to standard front-side deposition, backside deposi…
Poly(ethylene terephthalate) and polypropylene (PET/PP) were compounded and pelletized with a single-screw extruder. Standard ASTM tensile test specimens were made by injection moulding. The blends are stronger and stiffer than the plain PP specimens. The addition of a compatibilizer, EPOLENE E-43, is found to improve…
We report the synthesis of cadmium sulfide containing a periodic array of nanometer-sized cylindrical pores. The nanostructured cadmium sulfide was synthesized in a hexagonal lyotropic liquid crystal by the reaction between H2S and various cadmium salts. Interestingly, the counterion of the cadmium salt had a pronounc…
The isothermal oxidation of HfC single crystals with (100) orientation was carried out using an electromicrobalance at temperatures of 600° to 900°3C at an oxygen pressure of 2 to 8 kPa. Nonisothermal oxidation was performed by a simultaneous thermogravimetry—differential thermal analysis—mass spectrometry analysis. A…
A modern technique for a controlled surface modification of synthetic fibres consists of irradiation with a pulsed UV laser, which can be used to execute submicrometre surface treatment on polymers. Many types of synthetic fibres, e.g. poly(ethylene terephthalate), polyamides and aramides, show a characteristic surfac…
The reaction of hydroxylamine with a series of metal porphyrins was examined in methanol/chloroform media. The reductive nitrosylation reaction was observed for the manganese and iron porphyrins, leading to a nitrosyl complex that precipitated out of the solution in good isolatable yield (80-90%). This reaction could…
The bis(stilbenyl)squaraines 6d − j,d ‘,j ‘ represent a novel class of NIR pigments. Their synthesis was performed by the regioselective 2-fold condensation of highly nucleophilic 3,5-dihydroxystilbenes 4d − j,d ‘,j ‘ with squaric acid ( 5 ). Depending on the substitution with alkoxy groups, the absorption maxima rang…
The bifurcation of the solutions of the nonlinear equilibrium problem of a weightless liquid bridge with a free surface pinned to the edges of two coaxial equidimensional circular disks is examined. The bifurcation is studied in the neighborhood of the stability boundary for axisymmetric equilibrium states with emphas…
Owing to the high efficiency of hepatocytes to take up bile acids, these endogenous compounds or their analogues can be considered as potential shuttles for delivering drugs to the liver. With the aim of using this strategy to target platinum(II)-related cytostatic drugs toward the hepatobiliary system, a cholylglycin…
Abstract This paper reviews mainly our recent investigations of two allomorphs of native cellulose, celluloses Iα and Iβ, carried out based on the composite crystal model by high resolution solid state 13 C NMR and electron microscopy. First the distribution of the two allomorphs in nature is described together with s…
A surface selection rule has previously been proposed for surface-enhanced infrared absorption that is analogous to the corresponding rule for bulk metals, in that molecular vibrations whose dipole moment change is perpendicular to the surface of the metal will be observable, and those vibrations whose dipole moment c…
Abstract Sodicity and clay type influence the decomposition of organic matter, and hence its accumulation in soil. In this study, the interaction of these two factors was examined. Two soils were prepared by mixing sand (57%) and silt (28%), separated from one soil, with clay (15%) separated from two soils. One clay t…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTShort Asymmetric Synthesis of (+)-α-Curcumene and (+)-XanthorrhizolA. I. Meyers and Diana StoianovaView Author Information Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872Cite this: J. Org. Chem. 1997, 62, 15, 5219–5221Publication Date (Web)…
A polymer dispersed liquid crystal was studied by dynamic light scattering. In the experiments, where no electric field is applied, the system exhibits additional slow dynamics to the ones observed in bulk nematic liquid crystals. This slow dynamics gradually disappears with an increasing electric field. While the mea…
The Leptospira meyeri serovar semaranga metX gene was identified by complementation of an Escherichia coli metA mutant, i.e., devoid of homoserine O-succinyltransferase. However, the MetX protein exhibited a homoserine O-acetyltransferase activity in agreement with its similarity to homoserine O-acetyltransferases. Re…
The reaction of [Ni(cyclam)](PF6)2 with K2CrO4 in water gave a chromato-bridged one-dimensional complex, catena-(μ-CrO4-O,O‘)[Ni(cyclam)]. In the complex, an intrachain ferromagnetic interaction is operative through the chromate bridges. The magnetic interaction was discussed in terms of the orbital topology of the fr…
Water-distilled volatiles from the leaves of Eryngium foetidum L. of Cuban origin were analyzed by a combination of GC and GC/MS. Forty-six components were identified, of which the major ones were found to be 2,4,5-trimethylbenzaldehyde (20.53%), hexadecanoic acid (12.05%) and carotol (9.94%).
Macromolecular conjugates of dextran and diethylenetriaminepentaacetic acid (DTPA), aimed to complex gadolinium, were synthesized to obtain contrast agents for nuclear magnetic resonance imaging with good paramagnetic properties and long intravascular persistence. These conjugates were prepared from dextran 40 (Mn = 3…