Materials Literature
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The structure of a high-pressure polymorph of Mn 3 O 4 has been refined using the Rietveld technique. The structure is confirmed to be isostructural with CaMn 2 O 4 (marokite), but with significant changes caused by the substitution of divalent Mn for Ca in the large triangular channels. The compound crystallizes in P…
The effects of Si and ZrO 2 dopants on the crystallization and phase transformation process in Li 2 O · Al 2 O 3 · 6SiO 2 glasses were investigated using differential thermal analysis, X‐ray powder diffractometry (XRD), and high‐resolution transmission electron microscopy (TEM) interactively. Phase separation was obse…
Abstract An adsorption method for determining the surface area of only the carbon of carbon-coated silica gel has been developed. In this method p-nitrophenol (PNP) was used as an adsorbate owing to its selective adsorbability on a carbon surface. This method was applied to carbon-coated silica gel prepared by a CVD m…
Trotz starker Verdrillung des konjugierten Systems reagiert das Tetrathiafulvalen‐Homologe 1 mit dem Elektronenacceptor Tetracyanchinodimethan zum Dikation 1 2⊕ . In 1 2⊕ [(TCNQ) 4 ] 2⊕ ist das Anthracengerüst eingeebnet, und die Dithiolringe sind 86° gegen die Anthracenebene verdrillt. Die 1:4‐Stöchiometrie des hoch…
NRC publication: Yes
The anodic polarization behavior of the Ag-Hg matrix phase of dental amalgam (gamma 1) and the rate of mercury dissolution were examined as a function of the tin content. The objectives were to determine the effect of tin on the electrochemical behavior and dissolution of mercury and to provide evidence on whether tin…
Abstract Three polypropylene polymer samples possessing three different molecular weight distributions (MWD) ranging from narrow to broad, but having the same melt flow, were studied. The three resins were used to produce uniaxially oriented stretched tapes, which were evaluated for physical properties and morphologic…
Abstract Oxorhenium(V) porphyrins ReO(P)X (X = Cl, Br) or [ReO(P)] 2 O, or trichlororhenium(V) porphyrins ReCl 3 (P) (P = OEP, TPP, TTP, TAP, TCIP, TMP) 2,3 , respectively, are transformed into nitridorhenium(V) porphyrins ReN(P) with hydrazine hydrate in the presence of ethanol, in good yields. The diamagnetic comple…
A model is presented for the light-induced bond-breaking processes in arsenic chalcogenides which, based on theoretical calculations of coordination defects, accounts for the details of recent experimental light-induced electron-spin resonance experiments on amorphous ${\mathrm{As}}_{\mathit{x}}$${\mathrm{S}}_{1\mathr…
The thin films obtained by a spin-coating of soluble co,per phthalocyanines with tetra-alkylthio substituents have been found to have the x kJ) values in the order of magnitude of l0h1 esu. It is almost the same value as that of metallophthalocyanine with an axial ligand, i.e., vanadiumu-oxo phthalocyanine and so on.…
The crystal structure of the Asp-199----Asn mutant of chloramphenicol acetyltransferase (CAT) has been determined to 2.35-A resolution. In wild-type CAT Asp-199 is involved in a fully buried intrasubunit salt bridge with Arg-18, an interaction that is adjacent to the active site. Replacement of aspartate with asparagi…
The crystallographic structure of 3Al2O3-2SiO2 mullite has been studied by means of high-resolution electron microscopy. The best conditions for atomic imaging of this compound are discussed relative to the atomic resolution microscope at Berkeley. [001] multibeam images have been produced at a resolution better than…
The geometric isotope effect can be seen in many types of hydrogen-bonded crystals such as tetragonal ${\mathrm{KH}}_{2}$${\mathrm{PO}}_{4}$-type crystals in which the hydrogen-bond lengths expand as deuterium atoms are substituted for the hydrogen atoms. This paper explains the mechanism behind the geometric isotope…
We developed a new magnetic material R3T system, where R is a rare earth metal and T a transition metal, used as a regenerator matrix in a conventional two-stage Gifford-McMahon (GM) type cryocooler. These compounds, especially Er3Ni (Erbium 3 Nickel), possess extremely large heat capacities between 4 K and room tempe…
Abstract The crystal structure of the new mineral kamchatkite, a = 9.741(5), b = 12.858(6), c =7.001(3)Å, space group Pna 2 1 , Z = 4, has been determined through direct methods using 1430 intensities and refined to a final discrepancy index R = 0.055. It contains (SO 4 ) tetrahedra and Cu octahedra interconnected by…
Abstract The level of adsorption of enantiomeric tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy) 3 2+ ) by seven different smectite samples was found to be controlled by the total surface area of the clay. The level corresponded to one monolayer. The adsorption of the racemic mixture was lower for all samples, being limite…
The diamond film polishing apparatus with hot metals has been presented . Diamond films deposited by both microwave plasma CVD and arc discharge plasma jet CVD are used as workpieces . As a diamond film sways on a polishing plate made of an iron or a nickel heated to 75O''95O C it is finished to flat and glass-like su…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and x-ray crystal structure determination of a novel chiral heteropolyanion: the "3:1" octadecatungstohexaphosphateRafael Acerete, Juan Server-Carrio, Angel Vegas, and Martin Martinez-RipollCite this: J. Am. Chem. Soc. 1990, 112, 25, 9386–9387Publication Date (Prin…
The feasibility of photoelectron Auger electron coincidence spectroscopy from solid surfaces has been demonstrated by Haak et al. [Ph. D. thesis, University of Groningen, The Netherlands, 1983; Phys. Rev. Lett. 41, 1825 (1978); Rev. Sci. Instrum. 55, 696 (1984)]. They were able to show the considerable power of the te…
A simple theory of potential and current distributions developed elsewhere, based on the parallel‐plate electrochemical cell under linear kinetics, is applied to electrochromic windows. In our case, only the working electrode has appreciable resistance. The model permits a predictive analysis of the effects of operati…