Materials Literature
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Pyridine-catalyzed reactions of methyldichlorosilane with bis(trimethylsilyl)carbodiimide afford a dichlorosilane-derived anhydrous sol–gel material. Both trimethylchlorosilane formation and Si–H disproportionation act as crosslinking mechanisms. The dried gels form amorphous or crystalline materials, depending on th…
LaGaO3 is reported to undergo a low-temperature phase transition from Pnma to R3c at 418 K. The phases involved in the low-temperature phase transition of LaGaO3 were determined using Raman spectroscopy from 77 to 773 K. There is a total of 17 bands observed in the room temperature (294 K) Raman spectrum, namely, 55(A…
Basic regularities of silicon nitride based materials microstructure formation and development in interrelation with processing conditions, type of sintering additives, and starting powders properties are discussed. Models of abnormal or exaggerated grain growth are critically reassessed. Results of several model expe…
The existence of a global gene regulatory system in the hyperthermophilic archaeon Sulfolobus solfataricus is described. The system is responsive to carbon source quality and acts at the level of transcription to coordinate synthesis of three physically unlinked glycosyl hydrolases implicated in carbohydrate utilizati…
Observations and analysis of hypersensitive P03→3F2 transition of Pr3+ ion are reported in a series of fluoride (fluoroindate, fluoroaluminate, and fluorozirconate) glasses. The data in fluoride families are also compared with the data on the selected tellurite and sulfide glasses. The structure of dopant sites in flu…
One of the important considerations in the selection of a polymer blend for a practical application is how it resists crack growth and/or failure from a material flaw, under static or fatigue conditions. The blending of two or more rubbers is a useful technique to improve certain properties not inherent in a single ru…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTKinetic Stabilization of Biopolymers in Single-Crystal Hosts: Green Fluorescent Protein in α-Lactose MonohydrateMiki Kurimoto, Paramjeet Subramony, Richard W. Gurney, Scott Lovell, Jean Chmielewski, and Bart KahrView Author Information Department of Chemistry, Box 3517…
A method for the synthesis of boron nitride (BN) fullerene-like nanoparticles (FNPs) and (BN) x C y nanotubes in large quantities using carbon nanotubes as templates is presented. Boron oxide vapor was reacted with nitrogen gas in the presence of carbon nanotubes (CNTs) at 1573 K in a boron nitride crucible to form BN…
Stress corrosion cracking (SCC) on the external surface of pipelines contributes to the major failure of pipelines. The great majority of SCC is intergranular and occurs in a carbonate-bicarbonate environment. Metallurgical factors affecting SCC are still vague and therefore have been studied. Uniform microstructures,…
Abstract The effects of nucleating agent, temperature of crystallization, and degree of machine direction (MD) orientation on the mechanical, optical, and thermal properties of biaxially oriented polypropylene (BOPP) films were investigated. Addition of nucleating agent improved only the initial tear resistance in the…
The technique of real-time electronic speckle pattern interferometry (ESPI) is proposed to study the diffusion process of surfactants and proteins in gels. The diffusion coefficient is simply and directly determined from the interferograms. The experiments were carried out on a series of surfactants as well as on a my…
Five silsesquioxanes (RSiO3/2)2n with R = siloxy and n = 4, 5 have been investigated by X-ray crystallography, MALDI-TOF mass spectrometry, and differential scanning calorimetry (DSC).
A comparative crystallographic analysis of the conformation of porphyrin diacids with various substituent types reveals considerable differences in the degree of nonplanarity and distortion modes. Diacids of 5,10,15,20-tetraarylporphyrins generally exhibit typical saddledistorted macrocycles with displacements of the…
The thermal stability of the powder or film forms of Eudragits L, S, and L30D and carbopol polymers was qualitatively investigated by microscopic reflectance Fourier transform infrared spectroscopy equipped with differential scanning calorimetry (FT-IR/DSC microscopic system). DSC and thermogravimetric analysis (TGA)…
A quaternary ammonium salt of poly(oxyethylene) methacrylates containing a quaternary ammonium group was designed and synthesized as a single-ionic solid polyelectrolyte. The ionic conductivity of the polymer is about 10−5 S/cm at room temperature. Furthermore, when a small amount of water or aqueous KOH solution was…
Phase change rewritable optical recording media contain a chalcogenide layer, e.g., GexSbyTez, that undergoes a transition between the amorphous and crystalline phases (by absorption of laser energy). Differences in their optical constants [n,k] result in reflectivity differences in the multilayer optical devices. We…
Electrical conductivity and dielectric relaxation studies with a wide range of compositions of lithium ion conducting glasses belonging to the ternary glass system Li2SO4-Li2O-B2-O3- have been carried out over the temperature range 150-450 K and between 10 - 10(7) Hz. DC conductivities exhibit two different activation…
Dissipative dynamics of a tunneling, methyl-like rotor, whose spatial coordinate is weakly coupled to a thermal bath, are described using the reduced density matrix (RDM) approach. It is found that, owing to selection rules imposed on thermally induced transitions by the symmetrization postulate, there are two sorts o…
Copolymers of styrene and ethyl acrylate are prepared by radical polymerization and analysed with respect to microstructure by means of nuclear magnetic resonance. Using 13C NMR, the compositional styrene- and ethyl acrylate-centered triads can be determined and compared to theoretical values. Good agreement between e…
A practical‐scale cell with a trickle‐bed electrode was developed for on‐site electrochemical production of hydrogen peroxide by the cathodic reduction of oxygen. Terminal voltage and current efficiency were affected by the dispersions of liquid and oxygen gas in the trickle‐bed cathode and by the current density. Cur…