Materials Literature
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Abstract Die Reproduzierbarkeit der Synthese von Poly(p‐phenylen‐1,3,4‐oxadiazolen) in Oleum Kann durch eine veränderte Monomerzugabetechnik, gemessen an der Standardabweichung der relativen Lösungsviskosität, um eine Größenordunung verbessert werden. Die Polykondensation verläft unter deutlich milderen Bedingungen in…
Abstract This article describes the factors considered in the analysis of brazeability and solderability of engineering materials. These are the wetting and spreading behavior, joint mechanical properties, corrosion resistance, metallurgical considerations, and residual stress levels. It discusses the application of b…
Gaseous impact testing has been accomplished in assorted ways dating back to at least the 1950s. ASTM Committee G-4 grappled with disparate views and melded them into ASTM G 74 in 1982. Criticized for being both too sensitive and too insensitive, recent data has unfortunately also led to calls for the test's abandonme…
グリコールを主とする化学的処理方法によって廃棄硬質ポリウレタンフォームが分解された. IRとGPCの分析により, 分解生成物は多量の反応性ポリウレタンオリゴマーを含むことが認められた. アミン/グリコール比・反応時間の増加, 反応温度の上昇は, 反応生成物の水酸基価・アミン価の増加と粘度の低下をもたらす. この分解生成物を直接エポキシ系接着剤の硬化剤として利用するため, キュア条件, 分解生成物/エポキシ樹脂比, 通常のエポキシ接着剤系で使用されているアミン硬化剤・添加物との併用などが検討された. その結果, 廃棄硬質ポリウレタンフォームの分解生成物はエポキシ系接着剤の接着強度を高めることが認められ, その有用性が明らかとなった.…
Abstract The magnetoplumbite crystal LMA is grown by the CZ technique. The orientations of all developing facets on the crystals are determined by means of X‐ray and optical methods, and Miller indices are calculated. According to the PBC theory, the relations between the morphology of LMA crystal and its structure ar…
Abstract When CdS and related II‐VI direct bandgap materials form semiconductor clusters in which the absorbance properties are dominated by quantum size effects, the emission properties are particularly sensitive to surface defects, which are associated with the unfilled valence of surface Cd 2+ ions. These mid‐bandg…
With this issue a new Section of Acta Crystallographica, one devoted to biological crystallography, is initiated.The determination of crystal structures of biological macromolecules provides a wealth of information that makes this area of crystallography highly significant, exciting, and of general interest to a wide…
When tetrapropylammonium cations are removed from the α cavities of SAPO 37, but tetramethylammonium cations are still in the β-cages, a shift in the vibrational frequency of hydroxy groups to lower frequencies, with the corresponding appearance of stronger acid sites is observed; this is a consequence of the increase…
Abstract The new quaternary sulfides Ba 2 LaAg 5 S 6 and Ba 2 YAg 5 S 6 have been synthesized by the reaction among BaS, La 2 S 3 or Y 2 S 3 , Ag, and S at 1000[unk]C. The crystal structure of Ba 2 LaAg 5 S 6 has been determined by X-ray diffraction techniques. Crystal data: space group C 2/ m , M = 1145.3, Z = 2, a =…
A thousand thermal cycles of vanadium hydride across the β-γ mixed phase region decreased the reversible hydrogen storage capacity and increased the absorption/desorption pressure hysteresis ratio. Thermal cycling also produced a large increase in hydride surface area. Nevertheless, X-ray diffraction and transmission…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDeposition and characterization of polyimide Langmuir-Blodgett filmsKarl F. Schoch Jr., Wei Fang A. Su, and Mary Grace BurkeCite this: Langmuir 1993, 9, 1, 278–283Publication Date (Print):January 1, 1993Publication History Published online1 May 2002Published inissue 1 Januar…
The salts [Co(η6-C6Me6)2]+[A]–(A = BPh4, NbF6, PF6 or SbF6) have been prepared from anhydrous CoCl2. Solid-state magnetic susceptibility measurements on these salts indicate that they all obey the Curie–Weiss law in the temperature range 30–300 K with µeff= 2.7, 2.8, 2.8 and 2.6 µB with corresponding θ values of –1.4,…
An earlier paper showed that dezincification of [alpha]-brass could be monitored electrochemically by simulating the solution that would develop in an anodically polarized cavity and then carrying out a test in this solution at zero volts vs a copper reference electrode. A prediction made from the earlier work was tha…
Monohydrocalcite from Shiowakka occurs as a constituent of calcite-dominant sinter precipitated in cold (14.5-17.8°C) saline (Mg2+ ?? 4, 000mg/l, Cl- ?? 4, 000mg/1) spring water with pH=6.67 and Mg2+/Ca2+=0.64. The idiomorphs under SEM are trigonal bipyramid with (Ca0.979 Fe2+0.013Mg0.005(Na2)0.003) as the cationic co…
The structure of newly prepared LiCuM3O9(M = Nb, Ta) has been determined from the powder X-ray diffraction pattern. The Rietveld refinement confirms that the compounds adopt a distorted perovskite structure [a= 7.5286(1)Å with I23 space group for M = Nb and a= 7.5178(1)Å with Im for M = Ta], which is compatible with t…
The importance of studying the influence of accumulated surface charge on surface flashover is demonstrated by on-site trapped charge measurements. Using a hemispherically tipped electrode on an epoxy resin plate, it has been shown that, at a critical surface energy density, a back flashover can be induced when the DC…
The reaction of [Bu4N]3V5O14 with RC(CH2OH)3 in methanol yields red crystals of [Bu4N]2[V6O13(OMe)3{(OCH2)3CR}](R = Et, 1; R =- CH2OH, la), a Vv cluster with the common hexametallate core {V6O19}, and a green filtrate from which were isolated light-green crystals of a mixed valence cluster [Bu4N]2[V6O8{(OCH2)3CR}2{(OC…
Activities of Li in molten alloys were measured in EMF studies by means of cells of the following scheme :
The diffusivity and solubility of hydrogen and deuterium in polycrystalline α-yttrium have been measured in the temperature range 1073–1373 K. The ratios of the measured diffusion coefficient of deuterium to that of hydrogen showed the classical value 1/√2. The activation energy of diffusion has been found to be 510 m…
Preface. Acknowledgements. Glossary of terms. Introduction. Basic electroplating. Surface preparation for plating. Plating operation. Plating process control. Plating quality assurance. Corrosion. Properties of tin, lead and tin-lead alloy. Tin plating. Tin-lead alloy plating. Plating quality problems. Chemical analys…