Materials Literature
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Abstract A comparison between the results of ab initio structure determination from X-ray powder diffraction data of a new cadmium hydroxide nitrate, Cd 5 (OH) 8 (NO 3 ) 2 ·2H 2 O ( SG C2/m), and those obtained from single crystal data is presented. The powder diffraction pattern has been analysed by an indexing metho…
A magnesium aluminosilicate glass‐ceramic (Corning Code 9606) has been heat‐treated at 900°, 1010°, 1200°, and 1260°C for up to 90 min., and the effect on the thermal conductivity between 30 and 300 K has been studied. It has been shown that the large increase of the thermal conductivity which results from the cerammi…
Abstract This paper describes analytical and experimental work which has been carried out to identify optimum process conditions for rotomolded products. The mechanical performance of the moldings has been assessed using tensile impact tests. It has been found that changes in the oven temperature or oven time cause a…
Z‐förmig und planar ist das Kation (Bild rechts) der Verbindungen Br MF (M = As, Sb), die bei der Reaktion von Br 2 mit XeF ⊕ MF entstehen. Dies entspricht einer AX 2 E 3 ‐Koordination, wie sie das Elektronenpaarabstoßungsmodell für Pentahalogen(+ 1)‐Ionen vorhersagt. Durch interionische Kontakte zwischen vier Fluorat…
A novel use of high-temperature superconductors for detecting defects in ferromagnetic and nonferromagnetic materials is reported. The magnetometer uses the even harmonics generated in a sample of YBaCuO when it is driven by an audio-frequency magnetic field. These harmonics arise from the nonlinear modulation of the…
A gradient-index rod whose length is a quarter of the periodic length works as a retroreflective element when its endface is coated with metal. This paper describes the experiment and theory on the reflectivity of such a rod and that of an array comprising seven or nineteen rods when they are illuminated by a Gaussian…
In this study, a multitechnique surface analytical approach is used to provide comprehensive surface molecular, structural, and thermodynamic information of a segmented Poly(etherurethane) (PEU) block copolymer (Texin-985). Through sample preparation methods described in this paper, a clean stable PEU material is prov…
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.