Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Discusses photoemission from solids and their surfaces. The authors concentrate in particular on angle-resolved photoemission which has been developed into one of the most powerful spectroscopic methods for studying solids, particularly when used in conjunction with light sources such as synchrotron radiation. They di…
Abstract Replicas and thin‐section electron microscopic studies were made of fractions of linear polyethylene covering the molecular weight range 2.78 × 10 4 to 6.0 × 10 6 for a variety of crystallizing conditions. Lamellar crystallites were found under all circumstances; and the supermolecular structure, or crystalli…
Diatom assemblages were monitored at weekly intervals over a 5 week period on Verde limestone, Supai sandstone, and Andesitic basalt substrata in a mountain stream in northern Arizona, U.S.A. Density, Shannon-Weiner diversity, evenness, and community similarity (SIMI) were used to compare colonization patterns and com…
Abstract Chelating organic acids hampered the hydrolytic reactions of Al and affected the nature of the crystalline aluminum hydroxides. Chemical composition, structure, size, nature of functional groups, and concentration of each organic anion, as well as the pH of the system, controlled the rate of Al(OH) 3 crystall…
The conversion of myofiber types was studied in the masseter, trapezius, longissimus, rectus femoris and vastus intermedius muscles of pigs at birth and 2, 4, 8 and 16 weeks of age. The histochemical reaction for ATPase was used to classify myofibers as type I (acid-stable, alkali-labile) or type II (alkali-stable, ac…
Abstract The use of different linking units to promote liquid crystal behaviour in rigid rod like polyarylates is reviewed. By systematically varying the proportion of non linear, meta, ortho , or bent bisphenol units in one particular series based on chloro‐ 1,4 phenylene: 4,4′ oxydibenzoate/terephthalate, complete s…
A core-associated enzyme, which catalyzes a nucleotide-pyrophosphate exchange with GTP, has been purified from vaccinia virions. The enzyme requires MgCl2 for activity, has an alkaline pH optimum, and specifically utilizes GTP as the exchanging nucleotide. The enzyme does not catalyze exchange of GMP with GTP. The GTP…
Abstract Rheological measurements were made on a variety of substantially aromatic copolyesters. All of them differ from flexible chain polymers in having unusually long relaxation times, estimated from shear rate dependence of viscosity and from melt elasticity. This behaviour is not accounted for by an unusual molec…
The spectral distribution of continuous x radiation, specularly reflected on a silicon mirror, is determined for various glancing angles near the K absorption edge. Anomalies of reflectivity are revealed, along with fine structure, in the photoabsorption spectrum beyond the edge. They are interpreted by the anomalous…
The loss of the orthogonality relationships in the incomplete pole-figure method leads to the necessity of solving a large set of equations to obtain the C coefficients of the orientation distribution function (ODF). The knowledge of the normalization factor Ni of each pole figure allows the large set of equations to…
Summary From the Buranga pegmatite, Rwanda, three occurrences of eosphorite-childrenite series minerals are described in assemblages of Li-Fe-Mn-bearing phosphates and in relationship with quartz-feldspar masses in close association with these assemblages. Electron-microprobe analyses of these terms (Mn,Fe) AlPO 4 (OH…
Double bolt loaded double cantilever beam specimens were used. Increasing chloride ion concentration increased the stress corrosion cracking (SCC) plateau growth rate up to about 0.6M, presumably by increasing the activation of the aluminum surface; at high concentrations the cracking was slower, perhaps because of lo…
Abstract Hydration/dehydration behaviour and the effect of various thermal treatments on montmorillonites saturated with lanthanide ions have been investigated by X-ray diffraction, thermal analysis (DTA, TG, DTG), IR spectroscopy and sorption-desorption of water vapour techniques. Heating at 150°C under 10 −5 torr di…
Observations of the retroreflective or opposition effect in the backscatter of visible radiation from common dielectric surfaces at small phase or observation angles have been made with a beam-splitting technique at zero phase angle with phase-angle resolution just under 0.2°, the smallest known resolution reported to…
SUMMARY Halite (NaCl), the most common halide mineral, is omnipresent in saline soils and frequent in alkaline soils. The present study, with a scanning electron microscope, is undertaken to evaluate the morphologies of this mineral in soils and a recent sediment. Salorthids, from Iran and Syria, and a recent crust fr…
The purposes of this study were (1) to determine any underlying considerations governing the perceptions of professional people as to the appropriateness of specific types of garment styles for female business dress and (2) to determine if a difference exists in the perceptions of appropriateness of garment styles by…
ABSTRACT Some antarctic diatoms form resting spores, differing morphologically and probably physiologically from vegetative cells. Differences in the type of resting stages became apparent while examining three species of endemic Antarctic diatoms (Bacillariophyceae, Centrales): Eucampia balaustium Castracane, Odontel…
Abstract The process of the polymerization of silicic acid can be divided into three steps: (1) a reaction between monosilicic acids, (2) a reaction between monosilicic and polysilicic acids, and (3) a reaction between polysilicic acids. The rates of the reactions between monomer-monomer, monomer-polymer and polymer-p…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStoichiometric inclusion compounds of cyclotriveratrylene and cyclotricatechylene with small neutral molecules. X-ray crystal structure of cyclotricatechylene di-2-propanolateJohn A. Hyatt, Eileen N. Duesler, David Y. Curtin, and Iain C. PaulCite this: J. Org. Chem. 1980, 45…
Both experimental and theoretical evidences are presented for polar and nonpolar contributions to liquid-crystal orientations on surface-treated substrates. Polar and nonpolar components of substrate surface energies are determined from contact angle measurements using polar liquids. Liquid-crystal orientations are ch…