Materials Literature
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Abstract Die Reduktion von C 6 H 5 ) 3 PAuCl mit B 2 H 6 in Benzol ergibt Au 9 , 2 [P(C 6 H 5 ) 3 ] 2 Cl, das mittels Molmassebestimmungen als Au 55 [P(C 6 H 5 ) 3 ] 12 Cl 6 charakterisiert wurde. Ein einfaches Modell, beruhend auf einer Anordnung dichtest gepackter Goldatome, führt zu einem Goldcluster, dessen Aufbau…
Abstract The degradation of poly(ϵ‐caprolactone) in rabbits, rats, and water was studied by measurement of changes in intrinsic viscosity, molecular weight, crystallinity, Young's modulus, and weight. Degradation proceeds by nonenzymatic random hydrolytic cleavage of ester linkages. The process is autocatalytic, and t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymer solutions near an interface. Adsorption and depletion layersP. G. De GennesCite this: Macromolecules 1981, 14, 6, 1637–1644Publication Date (Print):November 1, 1981Publication History Published online1 May 2002Published inissue 1 November 1981https://doi.org/10.1021/…
Type IV collagen was solubilized from a tumor basement membrane either by acid extraction or by limited digestion with pepsin. The two forms were similar in composition and the size of the constituent chains but differed when examined by electron microscopy and in the fragment pattern produced by bacterial collagenase…
A review is given of experimental and theoretical work on giant Raman scattering (GRS) by molecules adsorbed on the surface of submicroscopic particles of metals such as silver, gold, and copper. The GRS effect, i.e., the enormous (by a factor of 10') increase in the Raman cross section, is described together with exp…
The authors studied the electronic properties of single crystals of the layer-structured ternary compound AuTe 2 Br. The p-conducting material has a typical carrier concentration in the range 10 20 to 10 21 cm -3 . The angular dependence of the Shubnikov-de Haas oscillations has been investigated in order to map out t…
Abstract The problem of step motion during lateral growth in solid-solid phase transformations is re-examined. Results are obtained for the steady motion of an individual ledge when volume diffusion in the parent phase is the predominant contribution to the growth rate. A comparison is made between our results and the…
Essentially identical pretransitional smectic $A$ behavior is reported in both normal and reentrant nematic phases of mixtures of octyloxycyanobiphenyl (8OCB) and hexyloxycyanobiphenyl (6OCB). A phenomenological model which assumes an optimum density for smectic interactions explains quantitatively our correlation len…
Etch-decoration reveals that the rate of removal of carbon atoms exposed at monolayer steps on graphite surfaces depends on the population density of these edge atoms (the rate is higher at a low-density surface) and that carbon removal continues for a prolonged period after the oxygen supply in the gas phase has been…
All subgroups of the magnetic axial point groups are derived, and the invariant ones are indicated. These subgroups can be used in the determination of the symmetry of the low-temperature phase in phase transitions of crystals that are highly anisotropic in one direction (the ferroelectric transition of the chain-type…
The thermal expansion of VSe 2 from 40-1175K has been determined by X-ray diffraction. The lattice expansion is linear with temperature from 40 to about 300K with alpha a =18.6*10 -6 K -1 and alpha c =9.8*10 -6 K -1 . The behaviour alpha a > alpha c is anomalous for a layer compound. From the relation between the ther…
Abstract Ethinylbenzol ( 1 ) besitzt vier niederenergetische π‐Orbitale, die wegen ihrer Symmetrieeigenschaften differenziert auf Substitution im Alkinrest ansprechen. Der Verlauf der oberen π‐Ban‐den in den Gasphasen‐He(I)‐PE‐Spektren der Reihe 1‐13 (C 6 H 5 ‐ C C R) wird in Abhängigkeit von R untersucht. Relativ…
Abstract 4,5‐Dihydro‐7,9‐dimethyl‐3 H ‐benz[cd]azulen‐3‐on ( 1 ) sowie dessen N,N ‐Dimethyliminiumsalz 2 lassen sich durch Oxidation mit DDQ in die 3H ‐Benz[ cd ]azulenderivate 3 und 4 überführen. Das Salz 5 wird durch Alkylierung von 3 mit Triethyloxonium‐tetrafluoroborat erhalten, die Verbindung 6 aus 2 durch Reakti…
Infrared absorption spectra of various samples of hydrogen beta alumina are discussed with respect to the alternative concerning the existence of hydroxyl (OH - ) and oxonium (H 3 O + ) ions in this compound. Some results of inelastic and quasi-elastic neutron scattering are also given. It can be shown that the presen…
An effective medium theory is used to calculate the conductivity activation energy and the Seebeck coefficient for nearest-neighbour hopping in a band of Anderson localised states at the Fermi level. The results of these calculations are compared with experimental observations on cerium sulphide, fluorine-substituted…
New data are analyzed for the hard-sphere fluid at densities $\ensuremath{\rho}{\ensuremath{\sigma}}^{3}=0.95\ensuremath{-}1.08$ in the metastable range. In this region the diffusion coeffiecient behaves as in laboratory fluids, following a Doolittle equation with normal parameters rather than a Batchinski-Hildebrand…
The dominance of vacancy migration in grain boundary self-diffusion has been established by molecular-dynamics simulation of a bcc iron $\ensuremath{\Sigma}=5$ tilt boundary. The data yielded a reasonable value of the activation energy for migration and showed that the jump processes are highly structure dependent. Th…
Two structural phase transitions at 211 and 177 K are discovered and investigated in single crystals of cesium lithium molybdate by means of optical, dielectric, and X-ray methods. Spontaneous polarization and dielectric hysteresis loops are observed in both low temperature phases. Judging from X-ray powder data the s…
L'ordre magnétique dans LiCrO2 a été étudié sur monocristal par diverses techniques de diffraction neutronique. Grǎce à la méthode de Laue un vecteur de propagation unique k = [1/3, 2/3, 3/2] a été déterminé dans la maille multiple hexagonale (R3m). A l'aide d'un diffractomètre à quatre cercles, la mesure des intensit…
The technique of supersonic free jet spectroscopy can be used to study the structure and dynamics of molecules which have been cooled to far below their boiling points but which remain in the gas phase. Cooling of the internal degress of freedom, the molecular rotations and vibrations, produces a highly resolved and g…