Materials Literature
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Mouse mammary sarcoma cells, line EMT6/Ro, were exposed for 1 min to 1 MHz continuous wave ultrasound over a range of intensities from 0.5 to 30 W/cm2 (spatial peak). The presence of thymine base damage (TBD) products of the 5,6-dihydroxydihydrothymine type was determined by an alkali degradation assay. Production of…
The structure of wermlandite, (Mg7(Alo.57Feo.43h(OH)ls)2+ ((CaO.6'Mgo.4) (S04h(H20)u)2- has been determined and refined to an R value of 7.2 % based on 779 symmetry-independent reflections, of which 224 are unobserved (weighted R=6.1%). The cell dimensions are a=b=9.303(3), c=22.57(1) A, the space group is pjc1 with Z…
The measurements of the bend (k33) and splay (k 11) elastic constants and the amplitude of the smectic-like local ordering (obtained using X-ray diffraction techniques), have been made for a wide range of nematogens. The results reveal a strong correlation between k33/k11 and the strength of the smectic-like local ord…
The dependence of the hot ductility of Al-Mg solid solution on temperature, strain rate, grain size and solute content has been examined in detail by use of tensile test. At a constant strain rate, a ductility (reduction of area) versus temperature curve showed a remarkable trough. With increase in the strain rate, th…
The effects of grinding and drying (removal of water of crystallization) processes on the solidstate stability of ampicillin trihydrate were studied. The ground samples became more unstable as the grinding time increased. This phenomenon is considered to be due to a greater freedom of movement of water molecules, whic…
The thermal transition of carbamazepine polymorphic forms (forms I, II, III) in the solid state was investigated by X-ray powder diffractometry. From the kinetic analysis according to the method of Hancock-Sharp, it appears that the transition of form I to form III follows the mechanism of random nucleation and two-di…
Abstract Thermodynamics of K exchange were investigated in Ca‐saturated samples from the Ap horizon of an Evesboro soil from Delaware. At 283 and 298 K the selectivity curves (ln k v vs. X̄ K ) showed preference for K at low values of N K (mole fraction of K in solution) and for Ca at higher values. This selectivity r…
Reaction of protoporphyrin IX dimethyl ester with strongly activated dienophiles causes a Diels–Alder reaction to occur with the porphyrin periphery; elimination of the angular methyl group from these adducts gives monobenzoporphyrins.
(1984). Solid State Reactions - Theoretical and Experimental Aspects. Drug Development and Industrial Pharmacy: Vol. 10, No. 8-9, pp. 1175-1276.
Various microscopic surface structures of silica–alumina and silica–magnesia which can generate Brønsted acidity are discussed via molecular-orbital calculations using cluster models, together with indices for Brønsted acidity. Mechanisms explaining the origin of the Brønsted acidity of the solid surface are proposed…
The existence of isoelectric variants of bovine brain and human placental choline acetyltransferase was confirmed by chromatofocusing. The identification of molecular weight variants (bovine brain, Mr = 68,000 and 63,000; human placental, Mr = 66,000 and 64,000) was also demonstrated using sodium dodecyl sulfate-polya…
On presente des donnees de spectroscopie de photoelectrons induits par RX sur des verres de compositions 20Na 2 O-x R 2 O 3 -(80-x)SiO 2 et 20Na 2 O-xTlO-(80-x)SiO 2 (x=0-20 mol.%; R=Ga, In, Sc, Y ou La) 2 . Du thallium et des ions trivalents plus gros, In 3+ , Sc 3+ , Y 3+ et La 3+ sont incorpores dans les verres en…
Introductory investigations performed in order to make quantitative electron-probe microanalysis of very light elements such as boron, carbon, nitrogen or oxygen possible are described. The practical problems encountered in this kind of work are discussed in detail and, where possible, solutions are proposed. It is sh…
Crystal structure / Phase transition / Tricalcium silicate Abstract. Crystals of tricalcium silicate having a monoclinic superstructure transformed into a rhombohedral structure when they were heated at 1200 °C with gas flame: a=7.135(6) A, c=25.586(15) A, space group R3m, and contents of 9 x Ca2,9sSio,9sAlo,o40s.The…
For valves of the same diameter, type material of Stephanodiscus rotula, observed with light and scanning electron microscopy, has more total spines, more central strutted processes, and narrower mantles than does S. niagarae. However, these characters covary with diameter and with one another within each species. Thu…
The delayed hydrogen cracking behavior of cold-worked Zr-2.5Nb at temperatures above about 423 K depends upon the direction of approach to test temperature. Cooling to the test temperatures results in an increase in crack growth rate, da/dt, with increase in temperature, given by the following Arrhenius relationship d…
Time domain spectroscopy (TDS) is introduced for the first time to study the complex permittivity of liquid crystals. Measurements have been carried out for octylcyanobiphenyl (8CB) and the results are compared with literature data obtained by conventional steady-state methods in the frequency domain. It is also shown…
The mechanism of calcium sulfate dihydrate scale formation on reverse-osmosis membranes was studied by the introduction of a theory of crystallization. According to this theory, the values of the growth rate constant and the waiting period before nucleation obtained in long-term runs were reasonable in comparison with…
Theoretical and experimental work on the atomic structure of grain boundaries in metals and ionic crystals is reviewed critically. The dislocation and O-lattice models are described and their usefulness is assessed with reference to a worked example. The models derived from computer simulations of the atomic structure…
The recently discovered incommensurate phase of quartz close to the α-β transition has been investigated using Brillouin scattering. The frequency and the damping of the longitudinal (LA) and transverse (TA) acoustic modes propagating along the X, Y and Z directions have been measured as a function of the temperature…