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951.
In homogeneous negative phase velocity media, the Doppler and Cherenkov-Vavilov effects and the refraction and pressure of light are anomalous: they are inverse with respect to the corresponding effects in conventional media. Using the geometrical optics approximation, it is shown that the optical Magnus effect in inhomogeneous negative phase velocity media is also anomalous. The effect is demonstrated by considering a metamaterial consisting of parallel amorphous ferromagnetic microwires in a magnetic field. The metamaterial proves to be a left-handed one in the realistic region of the electromagnetic spectrum. The optical properties of such a left-handed medium can be controlled by the external magnetic field.  相似文献   
952.
The magnetic and petrochemical properties of basalts dredged from the rift zone at the southern part of the Red Sea at approximately 18° N are studied. The conditions of their formation and evolution are elucidated. The formation of basalts is found to occur in two stages differing in their magma supply rates and redox conditions. Special features of magnetic behavior and the anomalous geomagnetic field in the region were used to determine the sites where the rocks had experienced strong thermodynamic effects (tectonic strain, deformation, heating, etc.). The conditions in which natural remanent magnetization of the basalts was formed are estimated.  相似文献   
953.
954.
Studies in the field of development of polymeric oligoalkenesulfonate additives derived from sulfonated oligomers and exhibiting multifunctional effect when added to petroleum oils are summarized.  相似文献   
955.
A series of quasi-solid emitters is proposed for the X-ray fluorescence determination of bromine in different bromine-containing compounds. It is shown that sucrose-based glasses are the best emitters for analyzing alkali solutions of halogenated organic compounds, saccharose-based glasses and polymer films are best for analyzing powder samples, and organic gels offer most promise for analyzing liquid (at normal conditions) samples. It is noted that the proposed method can expand the possibilities of commercially produced element analyzers, which are currently intended for determining only C, H, O, N, and S in organic compounds and cannot be used for determining halogens.  相似文献   
956.
957.
Three new copolymers, namely poly(fluorenevinylene‐alt‐naphthalenevinylene) ( N ), poly(fluorenevinylene‐alt‐anthracenevinylene) ( A ) and poly(fluorenevinylene‐alt‐pyrenevinylene) ( P ), were synthesized by Heck coupling of 9,9‐dihexyl‐2, 7‐divinylfluorene with a polynuclear aromatic dibromide. The 9,10‐disubstituted anthracene was obtained exclusively for A while N and P were obtained as a mixture of two isomers with predominant the 1,4‐disubstituted naphthalene and 1,8‐disubstituted pyrene, respectively. The polymers were soluble in common organic solvents and decomposed above 370 °C. Their glass transition temperature increased from 58 to 110 °C by increasing the number of the phenyl rings of the polynuclear aromatic moiety. Rather high‐efficiency blue and blue‐greenish photoluminescence (PL) of these copolymers in solution was largely decreased in their films, indicating the presence of concentration quenching in the solid state. The OLED using these polymers demonstrated green EL in the case of copolymers N and A , and red EL in the P derivative with ηEL = 0.26–0.31%. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4661–4670, 2007  相似文献   
958.
959.
A. Montalbán  J. Tutor 《Surface science》2007,601(12):2538-2547
We have studied the vibrational frequencies and atom displacements of one-dimensional systems formed by combinations of Thue-Morse and Rudin-Shapiro quasi-regular stackings with periodic ones. The materials are described by nearest-neighbor force constants and the corresponding atom masses. These systems exhibit differences in the frequency spectrum as compared to the original simple quasi-regular generations and periodic structures. The most important feature is the presence of separate confinement of the atom displacements in one of the parts forming the total composite structure for different frequency ranges, thus acting as a kind of phononic cavity.  相似文献   
960.
Cationic polyelectrolytes were synthesized and used as semipermanent coating materials for capillaries in electrophoresis. The polyelectrolytes used were a homopolymer of poly(methacryl oxyethyl trimethylammonium chloride) (PMOTAC) and its poly(ethylene glycol) (PEG)‐grafted analogue. Two PMOTAC polyelectrolytes, with molar masses of 85,000 and 300,000 g/mol, and PEG‐grafted PMOTAC with a molar mass of 280,000 g/mol were synthesized and then characterized by size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR) spectroscopy. Attachment of the polyelectrolytes to the wall of the fused silica capillary for electrophoresis caused the electroosmotic flow (EOF) to reverse. The polyelectrolyte coatings were tested over the pH range 2–11 at different buffer ionic strengths, and the most stable and strongest anodic EOFs were obtained at acidic pH values with low ionic strength buffers. Between runs the capillary is merely rinsed for 2 or 3 min with the background electrolyte solution. With the PMOTAC coatings at pH values ≤5, the RSDs of the EOFs were less than 2.9% after 60 injections. The effects of the molar mass of the polycation and of PEGylation of PMOTAC on the interactions between the polycations and basic proteins were studied at acidic pH values. The differences in the effective electrophoretic mobilities, resolution values, and plate numbers of the proteins with the different coatings were due to the EOF, as demonstrated through calculations of reduced mobilities, relative resolution values, and relative plate numbers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2655–2663, 2007  相似文献   
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