Materials Literature
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Fifteen patients with severe acute vascular graft rejection (twelve of them steroid-resistant) treated with OKT3 monoclonal antibody (8) or antilymphocyte serum (7) were sequentially studied with duplex-Doppler ultrasonography (DDUS). Measurements of intrarenal resistance were obtained by means of the resistive index…
The Fr\'eedericksz transition and the dynamic response of homeotropical liquid-crystal films with a free surface (FS) induced by a perpendicular dc magnetic field have been studied theoretically and experimentally for two nematic substances: 4'-n-pentyl-4-cyanobiphenyl (5CB) and 4'-n-octyl-4-cyanobiphenyl (8CB). For e…
The electrical conductivity of barium titanate and 0.4% (mole) La doped barium titanate ceramics have been measured in the temperature range from 30 to 170°C with the help of a pA-meter at 10–90 V d.c. It is observed that doped ceramics give better positive temperature coefficient of resistivity (PTCR) effect than the…
Abstract The main‐ and side‐reactions which can occur during cationic ring‐opening polymerizations of heterocyclic monomers are discussed. Based on these general reactions these polymerizations are classified into three groups. (1) Living (or “almost living”) polymerizations provide the possibility to produce polymers…
[(BH 6 ) 2 ]S 4 ] 2− , [(BH 2 )Se 4 ] 2− : New Chalcogenoboron Hydride Anions with Adamantane Structure The reaction of THF·BH 3 /NaBH 4 (2: 1) with H 2 S produces Na[H 3 B‐μ 2 ‐S(B 2 H 5 )] ( 5 ) with hydrogen evolution. 5 reacts with an excess of H 2 S to give Na 2 [(BH 2 ) 6 S 4 ] ( 3a ), which is also formed in th…
Four novel β-cyclodextrin derivatives bearing Schiff base moiety were first synthesized by a convenient method with satisfactory yields, and the new host molecules were characterized by 1H-NMR, FT-IR, FAB-MS spectra etc.
Experimental aspects of conductivity and spin susceptibility measurements of conducting polymer films as a function of the redox state are discussed. An apparatus for in situ measurements in an electrochemical cell is described. The working electrode consists of two parts separated by an insulating gap which is bridge…
Abstract The hierarchical structures in PVC are such that the larger structures formed during polymerization are broken down to smaller structures during processing. These smaller structures have properties dependent on their microstructure. While PVC's microstructure is mostly amorphous, it contains crystallites that…
The formation of quasicrystalline phases in rapidly solidified Al-Mn-Ni alloys (Al60Mn11Ni4 and Al80Mn,3Ni7) has been investigated by X-ray diffraction and TEM techniques. X-ray diffraction studies indicate that the icosahedral phase preferentially nucleates on the side of the ribbon that is in contact with the copper…
A scanning tunneling microscope under potentiostatic control in visible light illumination was used in aqueous solutions to investigate an in situ dynamical light-induced morphological transformation of n-MoS2, a representative layer-type semiconductor electrode. In a KCl solution, light-induced corrosion originated f…
Abstract Hydroxy‐terminated poly(ϵ‐caprolactone‐co‐δ‐valerolactone) (PCV) copolymers were synthesized by the diol initiated bulk copolymerization of ϵ‐caprolactone (C) and δ‐valerolactone (V). The two homopolymers were semicrystalline, with almost identical melting temperatures; copolymerization significantly lowered…
Abstract Ethylene oxide was copolymerized with propylene oxide, epichlorohydrin or styrene oxide at various monomer feed compositions, using partially hydrolyzed organoaluminium compounds as catalysts. The copolymers obtained after doping with NaI form highly conductive polymeric electrolytes. Complex impedance measur…
Abstract Alkali (R)- and (S)-mandelates can change the helical pitch of cholesteric liquid crystals containing steroidal crown ethers in an enantioselective manner. In certain cases the pitch difference between (R)- and (S)-mandelates can be detected visually as a color change in the liquid crystals.
Deep photoresist gratings, slanted as well as unslanted, were produced holographically in clear Shipley 1400 photoresist. The diffraction efficiencies of these gratings were measured as a function of incident angle for three wavelengths with polarization perpendicular to the plane of incidence. It is shown that the re…
Simultaneous measurements of the gyration, birefringence, and rotation angle of the optical indicatrix of Rochelle salt were successfully performed by using high-accuracy universal polarimetry. The three phases of the crystal were found to be optically active. It was revealed that the origin of ferroelectricity of the…
A refinement of a simplified method, based on line-beam response functions, is presented for performing skyshine calculations for shielded and collimated gamma-ray sources. New coefficients for an empirical fit to the line-beam response function are provided and a prescription for making the response function continuo…
We study bond-orientational order in liquid Si via Monte Carlo simulation in conjunction with empirical two- and three-body potentials of the form proposed by Stillinger and Weber. Bond-orientational order (BOO) is described in terms of combinations of spherical harmonic functions. Liquid Si is found to have pronounce…
New polyesters containing thianthrene tetraoxide were synthesized by the interaction of 2,7-dichloroformylthianthrene-5,5′,10, 10′-tetraoxide with 2,5-bis(p-hydroxybenzylidene)cyclopentanone, 2,5-divanillylidenecyclopentanone, 2,6-bis(p-hydroxybenzyiidene)-cyclohexanone, 2,6-divanillylidenecyclohexanone, and 2,7-bis(p…
We compared two different formulations, the electron-field and electron-electron models, for electron-plasmon scattering in bulk semiconducting materials. The calculations employ three different expressions for the plasmon dispersion relation and are made at two different temperatures. It is found that the functional…
Abstract In this work three different techniques were used to determine the crystallinity of polyethylene. After different pretreatment HDPE, LLDPE, and LPDE samples were investigated by density measurements, differential scanning calorimetry, and Raman spectroscopy. The results were compared and relationships were es…