Materials Literature
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High-resolution adiabatic calorimetry has been used for the study of the nature of the NAC (nematic-smectic A-smectic C) multicritical point in the mixture of 4-n-hexyloxyphenyl-4'-n-octyloxybenzoate (608) and 4-n-hexyloxyphenyl-4'-n-decyloxybenzoate (6010). The N-C transitions are weak first order however the transit…
Abstract Rock samples representing different soil parent materials from the Jurassic, Cretaceous and Tertiary periods in eastern Saudi Arabia were investigated for their mineralogical and chemical properties. Samples from five soil profiles found on these rocks also were studied. Palygorskite was found to be the domin…
Two experimental determinations of W, the average energy required to produce an ion pair in dry air, for electrons arising from 60 Co radiation, are presented. One is based on calorimetric and ionometric measurements of absorbed dose in graphite, the other on activity and exposure measurements. The values obtained by…
By in situ high-pressure i.r. spectroscopy acetyl [MeCO] as a possible intermediate for C2-oxygenates and acetate surface species are observed over Rh/SiO2 and Rh–Mn/SiO2 catalysts in a CO–H2 reaction (CO/H2= 0.5, 30–50 kg/cm2, 230–270 °C).
Loss peaks are observed in both the real and imaginary parts of the a.c. conductivity of a-Si and a-Ge samples at around liquid nitrogen temperatures. The data is plotted in a way suggested by a recent scaling theory which yields almost universal curves for the loss peaks. The decay length α+1 is the only adjustable p…
An inversion barrier between enantiomorphic saddle conformers of nickel(II)ccccc-octaethyl-pyrrocorphinate in solution is observed by 1H n.m.r. spectroscopy.
Skin forms a link through which the forces required to hold and manipulate objects are transmitted from the musculoskeletal system to the objects; while these forces are necessary for most work, excessive forces can be injurious. This paper discusses some of the mechanical properties of skin and discusses how they are…
Crystals of the monoclinic compound Cu(SeO 2 OH) 2 were synthesized under hydrothermal conditions. The crystal structure was refined to R w = 0.023 for 952 unique data up to sin θ / λ = 0.81 Å −1 ( a = 5.7662(4) Å, b = 7.3521(6) Å, c = 6.4474(5) Å, β = 93.28(1)°, Z = 2, space group P 2 1 / n ). The Cu atom is [4 + 2]…
Observations of damage during the creep rupture of poly‐crystalline alumina have revealed an important influence of shear bands on the failure process. The shear bands are regions of appreciable damage, consisting of high densities of facet‐sized cavities. The cavities within the bands become crack nuclei at shear ban…
The adsorption of NO on pure MgO at 77 K gives N2O2(cis) dimers on {100} faces and NO–2(nitrite), N2O2–2(hyponitrite) and N2O2(cis) dimers on edges and steps. The hyponitrite anions (which are the precursors of N2O gas formation) and the dimeric N2O2(cis) species are absent at room temperature, while the NO–2 species…
Some solutions of rigid polymers like DNA or PBLG display at the same time cholesteric order and local hexagonal order. The coexistence of two such orders is impossible on long distances. Two cylindrical geometries of molecular arrangements, extending transversally on a distance of the order of the pitch, and achievin…
The crystal structures and the magnetic properties of two novel complexes, of formula [Cu2(C17H27N4O)(C2H3O2)L]PF6, L = N3 or NCO, with a 1,1-azido or cyanato bridge in addition to phenolato and acetato bridges have been investigated and the relevance of the results to the fields of molecular magnetism and bioinorgani…
Abstract Die neuen Verbindungen Cs 2 P 2 S 6 und K 2 P 2 S 6 kristallisieren orthorhombisch in der Raumgruppe Immm, Z = 2 mit den Gitterkonstanten und sind dem Tl 2 P 2 S 2 isotyp. Sie enthalten diskrete P 2 S 2 2− ‐Anionen als Baugruppen. Zwei PS 4 ‐Tetraeder sind über eine gemeinsame Kante zum Hezathiometadiphosphat…
Sustained release systems were made by incorporating 5-fluorouracil (5-FU) in an ethylene-vinyl alcohol copolymer. When exposed to aqueous medium, the delivery systems released the drug slowly and continuously. Upon exposure to ultrasound, the drug was released at a much higher rate. Release rates returned to base lin…
On considere que des modifications de la raie centrale de resonance magnetique nucleaire de 11 β des groupes borates en coordination 4 peuvent se produire si du fluor est incorpore dans le reseau vitreux. On discute de ce phenomene et on le prouve en comparant la theorie avec l'experience et on reconsidere les etudes…
The structures of the complexes [Cu2(L1)2(N3)2][ClO4]2(1){ L1= 1-(imidazol-4-yl)-2-[(2-pyridylmethylene)amino]ethane} and [Cu2(L1)2(N3)3]Cl·2H2O (2) have been determined by X-ray methods. Complex (1) contains discrete [Cu2(L1)2(N3)2]2+ cations which are located at centres of inversion. The geometry around each copper(…
An investigation was undertaken to elucidate the preparation conditions and magnetic properties of W-type hexaferrite powders with the formula AM 2 Fe 16 O 27 (A=Ba or Sr, M=Fe 2+ , Zn+Cu, Zn+Cd, Zn+Mg). A pure W-phase was formed by firing a mixture of carbonates and oxides in the appropriate molar ratio at 1200^° ∼14…
The infrared spectra of Cu(en)(TCNQ)2 and Cu(en)2(TCNQ)2(en: ethylenediamine, TCNQ: 7,7,8,8-tetracyanoquinodimethane) have been shown to exhibit totally symmetric TCNQ Ag bands activated by a vibronic process in addition to inherently i.r.-active Bu bands. In the spectrum of Cu(en)2(TCNQ)3 some Ag modes were developed…
Bis[1,2,5]thiadiazolo-tetracyanoquinodimethane (1) was prepared and found to form a highly conductive complex with tetrathianaphthacene.
A prerequisite for the aseptic packaging of food is the UHT or HTST process used for sterilizing the food. These processes are defined. The history, microbiology, and engineering principles of aseptic processing and packaging are covered. Attainment of sterility and acceptable levels of spoilage are discussed. Methods…