Materials Literature
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Copper and silver oxide share the rather unusual cuprite structure, formed by two interpenetrating networks of corner-sharing M 4 O tetrahedra ( M = Cu, Ag). Negative thermal expansion of the cell parameter has been observed from 5 to about 200 K for Cu 2 O and up to 470 K for Ag 2 O by powder diffraction. In the case…
MCM‐41 and MCM‐48 were functionalized with cobalt by two methods, incipient wetness impregnation and co‐precipitation, and were characterized by XRD, N2‐sorption, and TPR. The incipient wetness impregnation method provides a high dispersion of small cobalt oxide particles, while the mesoporous structure and high surfa…
Terbium-doped nanocrystalline yttrium aluminium garnet phases, Y3Al5O12:Tb 3+ (YAG:Tb 3+ ), were obtained by using rare-earth nitrates as the starting materials, together with citric acid and ethylene glycol according to the Pechini method. Thermogravimetric and differential thermal analysis were used to study the the…
Relationships between singularly perturbed equations and equations with hysteresis are discussed. 1.1 Introduction 1.1.1 Stop and Play nonlinearities Singular perturbations (including time relaxation) and hysteresis phenomena are among the most common strongly nonlinear elements which arise in almost any industrial, p…
Thermal conductivity is an important material property of the bulk thermoelectrics. To improve ZT a reduced thermal conductivity is always desired. However, there is no standard material for thermoelectrics and the test results, even on the same material, often show significant scatter. The scatter in thermal conducti…
Closed form analytic approximations are proposed for complex impedance (capacitance and Q-factor) of capacitors formed by two coplanar rectangular conducting patches sandwiched between dielectric layers. The computations using proposed formulas are at least an order of magnitude faster in comparison with the commercia…
The temperature dependence of the relaxation of poly(aniline) (Pani) and poly (o-toluidine) (POT) in aqueous eutectics of and in the temperature range K, was investigated. As the temperature decreased the anodic peak parameters, increased, increased, and decreased. The data is interpreted qualitatively within the fram…
Abstract Crystals of nominal composition Ca(Nb 0.8 Ti 0.2 )O 3.4 , an n = 5 member of the homologous series A n B n O 3n+2 , have been synthesized by floating-zone melting. The material was found to be multiphase consisting also of the n = 6 type. A good single crystal of this n = 6 type was found and the crystal stru…
The synthesis and characterization of a water-soluble biodegradable multiblock polyurethane based on poly(ethylene glycol) blocks interconnected by a pentapeptide derivative N , N' -bis(aspartylprolyl)lysine is described. The pentapeptide linkages are susceptible both to chemical hydrolysis in neutral and mild acid me…
Well-defined CoFe2O4 nanoparticles embedded in amorphous SiO2 matrix have been synthesized by sol-gel method, characterized and investigated by Mossbauer spectroscopy and magnetic measurements. The mean particle size was found to increase from 3 to 15 nm by varying the temperature of a subsequent annealing from 800 to…
Abstract This article describes the processes involved in the production of hafnium and its alloys. It discusses the physical, mechanical and chemical properties of hafnium. The aqueous corrosion testing of hafnium and its alloys is detailed. The article reviews the corrosion resistance of hafnium in specific media, n…
Abstract Infrared (IR) spectroscopy has been used for routine characterization and identification of clay minerals for many years (Stubican and Roy, 1961; Farmer and Russell, 1964; Farmer, 1974; 1979; Hawthorne, 1988; Russell and Fraser, 1994; Johnston and Wang, 2002; Madejová and Komadel, 2001; Schroeder, 2002). Most…
Abstract: Mathematical modelling of austenite decomposition has been investigated. Phase portion in steel are predict based on hardenability curve of Jominy-specimen. The kinetic of phase transformations and hardness distribution have been estimated based on time relevant for structure transformation. The designed inv…
Clay minerals that are used for absorbent and adsorbent applications are most commonly calcium montmorillonite and palygorskite. Calcium bentonite deposits are found in North and South America, Europe, Africa, and Asia in many locations on the above continents. Palygorskite occurrences are in North America, Africa, Eu…
Rice straw after exraction with organic solvents was subjected to benzylation and acetylation reactions. Products of mentioned reactions were characterized by their FTIR and 1H NMR spectra. Thermal stability of products were evaluated by TGA thermograms and it was observed that the thermal stability of products was hi…
This paper reports the investigation results on the leakage currents (LC) on the ceramic as well as polymeric outdoor insulators. The LC waveforms were measured under various environmental conditions (humidity and pollution). The LC waveform parameters such as magnitude and harmonic content (as indicated by the total…
Sodium tungsten bronzes, Na x WO 3 have been prepared ranging in composition from x = 0.25 to 0.85 by solid state reaction at 850°C in argon atmosphere. X-ray diffraction and IR absorption spectra were used to characterizethe structure of the product samples. It was found two distinct phases in the range from x = 0.25…
"Se aplicó un tratamiento termoácido a una arcilla natural, proveniente de la región central del Perú, con alto contenido de esmectitas. La arcilla activada en solución ácida de HCl 2N a 90 o C fue probada como material adsorbente de colorantes tipo azoico utilizados en la industria textil. Los efectos de la activació…
SWNT were synthesized by arc‐discharge methods. The as produced material was treated by different procedures in order to get purified SWNT. The treatments led to higher conductivity values as measured on bucky papers. The SWNT were incorporated into a polymer matrix of polycarbonate by melt mixing using a small scale…
This work aims at characterizing the phase relations in the CuFe2O4/SiO2 system. Samples were prepared by the sol-gel method. Final heat treatment of the samples was carried out at temperatures in the range of 800–1100 °C. Final products were characterized by HR TEM, X-ray diffraction, magnetic measurements, and Mossb…