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。
Short-circuit losses were measured on a 213 MVA single-phase converter transformer at a number of frequencies between 60 Hz and 6 kHz. Using the results of these tests the harmonic losses during AC/DC converter operation were calculated. Variations of harmonic losses with transformer reactance, transformer winding str…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectroactive ladder polyquinoxalines. 1. Properties of the model compound 5,12-dihydro-5,7,12,14-tetraazapentacene and its complexesSamson A. JenekheCite this: Macromolecules 1991, 24, 1, 1–10Publication Date (Print):January 1, 1991Publication History Published online1 May…
Abstract The objective of this work was to study the obtaining of cationic starch by using a pilot scale twin‐screw extruder Clextral BC45 as a chemical reactor. The reagent was 3‐chloro 2‐hydroxypropyltrimethyl ammonium chloride (CHPTMA) and catalyst was sodium hydroxide (NaOH). In a first set of experiments extruded…
Abstract SIROQUANT is a suite of personal ccmputer programs which runs on an IBM-compatible 386 or 486 personal computer, and gives phase quantification of mineral samples hy Rietveld refinement using the full XRD profile. Eight phases can be quantified in a mineral with the 640 K RAM version and 11 in the EM version.…
The crystal structures of five hydrothermally synthesized representatives of the kieserite group Me(II)SO 4 •H 2 O [szmikite (Me=Mn), szomolnokite (Me=Fe), dwornikite (Me=Ni), gunningite (Me=Zn) and CoSO 4 •H 2 O] were refined in space group C2/c using single crystal X-ray data. The positions of the hydrogen atoms wer…
EDTA is a common additive to reduce the scale formation in industrial boilers. In the present paper, the effect of EDTA concentration on the nucleate boiling heat transfer coefficient of water has been determined with and without CaS04 present as a foulant. The effect of heat flux on the formation of scale deposits is…
Abstract Steam‐ and hydrogen‐induced effects on carbon monoxide oxidation at temperatures below 200°C were studied over an alumina‐supported Pt catalyst. These studies were complemented by measurements of rate expressions and IR spectroscopy. CO oxidation activity over alumina‐supported Pt, Pd and Rh catalysts was fou…
Aqueous molybdovanadates have been studied by 51V NMR spectroscopy over a wide range of metal-ion concentrations and temperatures in the range pH 1.4–7, and by potentiometry at 25°C. The structures of the anions cis-[Mo4V2O19]4–, cis-[HMo4V2O19]3–, [Mo5VO19]3–, [Mo4V5O27]5–, [HMo4V5O27]4– and β-[Mo7VO26]5– have been f…
The influence of the diameter on contamination flashover/withstand voltage of cylindrical insulators was investigated both for AC and DC. The increase in diameter of a cylindrical insulator significantly lowers the contaminated flashover/withstand voltage. The increase in diameter also lowers the contaminant deposit d…
Reactions of anhydrous CrCl3 with H2bpb and H2bpc [H2bpb = 1,2-bis(pyridine-2-carboxamido)benzene; H2bpc = 4,5-dichloro-1,2-bis(pyridine-2-carboxamido)benzene] in dimethylformamide and manganese(III) acetate with H2bpc in methanol, yielded the respective [CrIII(bpb)Cl]·xH2O, [CrIII(bpc)Cl]·H2O and [MnIII(bpc)(O2CMe)]…
Evidence is presented that faujasite-type zeolites with specific Si : Al framework ratios exchanged with Pd(NH3)42+ and Cu2+, catalyse the oxidation of ethylene into acetaldehyde, in exactly the same way as the homogeneous Wacker system [PdII and CuII in concentrated chloride solution]; the active centre is found to b…
It is shown that the exact pair-cluster coefficients corresponding to the fully correlated limit of cyclic polyene model satisfy the equations of the approximate coupled-pair theory with quadruples (ACPQ) approach, but do not represent any solution of the standard coupled-cluster method with doubles (CCD) equations. I…
About 400 pressure-tubes made of cold-worked Zr-2.5Nb are used in a CANDU power reactor to contain the nuclear fuel and the heat transport fluid, heavy water, at between 250 to 310°C at a pressure of about 10 MPa. The fracture toughness of these tubes is needed to determine if they are fit for service. We have measure…
Measurements of the asymmetry (Sherman) function for gold as a function of foil thickness have been made in a ``classical'' electron double-scattering experiment. Results are presented for incident energies of 50 and 120 keV at scattering angles of 45\ifmmode^\circ\else\textdegree\fi{}, 60\ifmmode^\circ\else\textdegre…
Ferroelectric relaxor characteristics are discussed in conjunction with the disordered arrangement of the constituent ions. Dielectric properties are characterized by giant and temperature-insensitive dielectric constants and large frequency dependence (dielectric relaxation). These properties are consistently explain…
The development of a sound physical view regarding crack quasi-stability during subcritical crack extension still remains challenging. It is evident that further progress requires exploration of the refined micromechanical processes of fracture. The present study emphasizes the experimental findings which indicate a c…
The formation mechanisms, phase stability, impurity incorporation, and morphological characteristics of lead niobates obtained by molten salt synthesis were studied by X‐ray diffraction analysis, scanning electron microscopy, and energy dispersive analysis. Results indicate that PbO is the fastdissolving component of…
The surface tension of the liquid binary alloys Ni–Cu, Ni–Sn, Fe–Cu, Fe–Sn, and Fe–Cr have been measured by the levitated droplet method. The results for Ni–Cu have been compared to duplicate measurements using the sessile drop method. It was found that the surface tensions of liquid Ni and Fe decrease sharply with in…
Ferroelectric phenomena in solids have been studied for seventy years. The history of their research is divided into five periods which are briefly characterized. Materials basis known today is overviewed. Factors motivating ferroelectric research are discussed and present status of practical applications is shown. Fi…
All articles of this category Alkynes are converted in good yield to alkyl and/or aryl substituted fumaronitriles and maleonitriles, a rich source of precursors to soluble tetraazaporphyrins.