Materials Literature
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The plate-shaped crystals of rat bone are arranged in parallel layers that form coherent structures up to the level of individual lamellae. The crystal layers of the thin lamellae are parallel to the lamellar boundary, whereas those of the thicker lamellae are oblique to the boundary. The basic structure of rat bone c…
Biquadratic coupling between two order parameters Q1 Q2 can lead to transitions between a phase with only one of the two order parameters active (phase I or II) and a mixed phase III in which both order parameters are symmetry breaking. Domain walls for positive coupling energies are chiral under thermodynamic conditi…
Abstract The use of plasma deposition to introduce sulfonate groups to the surface of a polyurethane was attempted. In previous work, the bulk incorporation of sulfonate groups was found to improve the blood contacting properties of the base polyurethane but physical properties in the hydrated state were adversely aff…
Abstract The structural hierarchy in injection molded blends of poly(ethylene terephthalate) (PET) and a commercial liquid crystal polymer (LCP), two immiscible polymers, was characterized at various blend compositions. The macroscopic core and skin have a gradient structure and are subdivided into ordered and disorde…
Abstract The average molecular interchain spacing (〈 R 〉) in Angstroms for amorphous polymers was calculated from the strong maximum in the wide‐angle X‐ray scattering (WAXS) diffraction scan using established equations. The half‐width ( HW ) of the maximum was used to qualitatively describe the distribution of 〈 R 〉.…
Abstract The effect of thermal treatment on compression‐molded poly(L‐lactic acid) (PLLA) has been investigated by means of viscosimetric molecular weight ( \documentclass{article}\pagestyle{empty}\begin{document}$$M_{w_v}$$\end{document} ) determination, differential scanning calorimetry (DSC), and dynamic mechanical…
A new approach to estimating the life distribution of electrical insulation at nominal conditions from the results of accelerated life testing of electrical insulating materials is introduced by the authors. A very general family of probability distributions is introduced and a best fit member of this family is used t…
The crystal structure and morphology of eutectic carbides are known to strongly determine the mechanical and tribological properties of Cr–Ni white cast irons. In an effort to improve these properties, investigators at the US Bureau of Mines have studied the effects of alloying additions of 0·0–1·8%Si, 0·0–6·7%Ni, and…
A quasi-finite element method for calculation of static fields in media with hysteresis is presented in this paper. The proposed method utilizes vector Preisach hysteresis model to describe the material behavior. Time-stepping technique is employed in which the evolution of the electromagnetic system is traced to comp…
The photochromic dinaphthofurofuran 1 undergoes a base-induced ring opening to yield 2, which instantaneously forms the dark blue dimeric quinone methide 3 on exposure to light. This compound is also the photoproduct of 1 and can react back to it both photochemically and thermally.
Abstract Metall(II) bis‐chelates of 1,3‐dithiole‐2‐thione‐4,5‐dithiolate (dmit) and 1,2‐dithiole‐3‐thione‐4,5‐dithiolate (dmt) undergo in CHCl 3 /CH 3 CN (ratio 1:24) photooxidation to the metal(III) bis‐chelates when irradiated at 313 nm. No side reactions were observed. There is no correlation between the quantum yi…
A new liposoluble porphyrin, 2,7,12,17-tetrahexyl-3,8,13,18-tetramethylporphin(THTMP), and its complexes with divalent (Mg, Co, Ni, Cu, Zn, Cd, Hg) and trivalent (Mn, Fe) metals have been synthesized. The electronic, infrared, and far-infrared spectra of these compounds were obtained in the same nonpolar, noncoordinat…
The forced global greenhouse effect and consequently rising sea levels are discussed. A brief survey of biomineralization processes and laboratory/field work encompassing mineral accretion (MA) is given, which is performed by placing cathodic forms and anodes in sea water or other electrolytes. It is proposed to grow…
Abstract The photolysis of iron carbonyl (Fe(CO) 5 ) adsorbed on titanium dioxide (TiO 2 , anatase) was studied by FT‐IR spectroscopy. When adsorbed Fe(CO) 5 is illuminated by visible and near‐UV light, the IR spectrum of its photolysis products is hardly observed, indicating that most of the Fe(CO) 5 is photodecompos…
In this paper, we consider two-dimensional dendritic growth from pure melt with inclusion of the anisotropy of surface tension. The interfacial wave theory previously established for axisymmetric dendritic growth is extended to this case. The results show that the effect of the anisotropy of surface tension on the sel…
Intergranular stress corrosion measurements have been made on Fe alloys in 1 M sodium sulfate at electrochemical potentials of +750 to +1250 mVSCE and in 55% calcium nitrate at 60°C and +750 mVSCE. Tests were conducted on Fe with variable grain-boundary S and P concentrations ranging from 0.04 to 0.23 monolayers of S…
In addition to conventional chemical etching (CE), electrochemical etching (ECE), is usually required for the initial tiny a tracks in polycarbonate (PC) to enlarge to visible etch pits. A model based on the 'vertical effective range' is proposed. The vertical effective range is a modified concept of the vertical mean…
Using a thermodynamic approach, we examine the role thermal expansion plays in determining the temperature dependence of band gaps and band offsets. Because of the large variation in the standard volume of electrons (or, equivalently, variation in conduction-band deformation potential) with symmetry of the conduction…
The water formation and decomposition reactions on Pt and the presence of intermediate OH were investigated by simultaneously measuring the OH desorption rate (by laser-induced fluorescence) and the overall H2O formation rate at different H2/O2 and H2O/O2 mixtures. These measurements were combined with computer modeli…
A new nortriterpenoid glycoside, named yemuoside [I] was isolated from Stauntonia chinensis. On the basis of chemical and spectral evidence, it structure was determined as 3-O-[alpha-L-arabinopyranosyl-(1----3)-alpha-L-rhamnopyranosyl-(1- ---2)-alpha-L-arabinopyranosyl]-30-noroleana-12,20(29)-di en-28-oic acid 28-O-[b…