Materials Literature
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The ASEA-STORA and Crucible processes make high speed steels that have the advantages of safe heat treatment and easy grinding. Dr P. Hellman, general manager of the HSS Division of ABB Powder-met in Surahammar, Sweden, describes both of these techniques and he compares them to an as-HIPed process for making high spee…
Organic nonlinear optical materials have developed to the point where applications in practical devices may now be contemplated. For second order nonlinear systems, these applications fall into two classes: frequency doubling and electro-optic switching and modulation. Chromophores already exist with values of the sec…
XPS spectra are presented for a thin film of a suboxide of boron formed by condensing B2O2(g) on a clean Ag foil substrate. Spectroscopic characterization of boron suboxides are important as these compounds may exist as surface intermediates in the oxidation of solid boron and of boron compounds. The B2O2(g) source co…
Abstract Wet scrubbing of flue gas to remove sulphur dioxide generates highly corrosive conditions in the operating plant. Conditions in the mixing zone are discussed in detail. Titanium has been evaluated and has been installed as a corrosion resistant liner in several major US plants. Competitive, cost effective ins…
Samples from profiles of 4 Gramusols (Vertisols) and 2 Mediterranean soils (Alfisols) from East Java and 2 each of Red Podzolic and Yellow Podzolic soils (Ultisols) from East Kalimantan have been investigated for the chemical and mineralogical characteristics. The Grumusols were weakly to moderately acid with a 30–40%…
This paper proposes a method using cluster analysis to classify X-ray diffraction lines of a multiphase mixture into different phases. This classification of lines is useful in both qualitative and quantitative phase analysis. An example of a three-phase mixture is given to illustrate this method.
A sui generis second-order transition in water solutions of Rochelle-salt crystal has been seen during measurements of both the solubility and solution densities versus temperature. Both the volume-expansion coefficients and the temperature differential of solution densities for several compositions along the solubili…
Abstract Single crystals and powder samples of Ca 2 Bi 5 O 5 and Ca 4 Bi 6 O 13 have been synthesized and studied using single crystal X-ray diffraction as well as X-ray and neutron powder diffraction. Unit cell dimensions were calculated using a least squares analysis that refined to a δ2 θ of no more than 0.03°. A t…
Abstract Chromating of metals has been used for a long time as corrosion protection. In this study two commercial products for chromating, one based on chromates (Iridite 9L‐6) and one with an addition of a polymer (Okem Coat F1), have been analysed on hot‐dip‐galvanized steel, 55% AlZn‐coated steel and pure Zn, Al an…
This paper discusses a generalized Stefan problem which allows for supercooling and superheating and for capillarity in the interface between phases. Simple solutions are obtained indicating the chief differences between this problem and the classical Stefan problem. A weak formulation of the general problem is given.
For an interface between two isotropic media the power reflectance Rν(ϕ) is an even function, Rν(ϕ) = Rν(−ϕ) of the angle of incidence ϕ; hence all the odd derivatives, Rν(n) = dnRν/dϕn (n odd), are identically 0 at ϕ = 0, independent of the incident polarization ν. When the incident light is unpolarized (ν = u), the…
Abstract Polycondensation processes include up to three distinct process stages: prepolymerization, polymerization, and finishing. One or more of these stages often have serious reaction rate limitations due to chemical equilibrium and the need to remove a condensate product. The problems arising in each process stage…
We report results of a Raman-scattering study of the n=4 (\ifmmode\pm\else\textpm\fi{}${\mathbf{q}}_{1}$,\ifmmode\pm\else\textpm\fi{}${\mathbf{q}}_{2}$) incommensurate phase (phase II) of biphenyl under hydrostatic pressure. We make use of a peculiar property of biphenyl, i.e., the stabilization under pressure of this…
Abstract A combination of SEM, AES and angle‐resolved XPS (ARXPS) has been applied to analyse the distribution of chemical compounds in the surface region of electrochemically etched molybdenum tips and to determine the contamination layer thickness. Carbon monoxide, graphite, molybdenum carbide and molybdenum oxide w…
Fine Fe particles produced by evaporation in Ar gas are applied to the observation of magnetic domains. Results of fundamental investigations of the patterns formed by the particles are described. Domain patterns of a Sm-Co polycrystalline magnet and magneto-optically recorded bit patterns in Tb-Fe-Co films are observ…
The BPh 4 − and BF 4 − derivatives of Co(NO) 2 (Py) 2 + 3 (Py = pyridine) have been prepared. In solution, whereas Co(NO) 2 (L) 2 + BPh 4 − (L = phosphane) and 3-BF 4 − are inert, 3-BPh 4 − decomposes rapidly in the absence of an excess of Py. Complex 3-BF 4 − crystallizes in the monoclinic system with two independent…
Abstract Thermal behaviour of HMS/RDX mixtures is studied by differential thermal analysis (DTA) and thermogravimetric analysis (TGA). It has been found that the temperature of polymorphic transformation of HMX shows an increase due to the presence of RDX. The enthalpies of the enothermic transformations depend on the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMelandrioside A, a Saponin from Melandrium firmumEun Hee Woo, Won Sick Woo, Gwendolyn N. Chmurny, and Bruce D. HiltonCite this: J. Nat. Prod. 1992, 55, 6, 786–794Publication Date (Print):June 1, 1992Publication History Published online1 July 2004Published inissue 1 June 1992…
Breakdown phenomena on surfaces of acrylic plates, 1 to 10 mm thick, were investigated under negative impulse voltage in atmospheric air. The 50% flashover voltage V/sub 50/ and the 50% corona inception voltage were measured, and the discharge phenomena were observed with an image converter camera, in the creeping dis…
The effects of additions of small amounts of Nb, Ti, Zr, and V on the intergranular precipitation of chromium carbides in N-bearing type 304 austenitic stainless steels have been studied by means of corrosion and tensile tests, x-ray diffraction measurement, and microstructure observation using optical and analytical…