Materials Literature
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A styrene–butadiene–styrene (20–60–20) linear block polymer was epoxidized in toluene and cyclohexane solutions with peroxyformic acid generated in situ. The epoxidized polymer, containing about 8% oxygen, exhibits greatly improved resistance to ASTM oils. It can be readily compounded with carbon black, and the unvulc…
Two additional carbohydrates are reported whose crystal structures trap electrons intermolecularly in single crystals x irradiated at low temperature, namely sucrose and rhamnose. Five carbohydrate and polyhydroxy compounds are now known which exhibit this phenomenon. The following characteristics of the phenomenon we…
Abstract The reversible stress‐induced crystal‐crystal phase transition of poly(tetramethylene terephthalate) (PTMT) has been studied using infrared spectroscopy. Two spectral regions were used to study this transition: the 900–1000 cm −1 methylene rocking region and the 1300–1550 cm −1 methylene bending region. The b…
Abstract The depolarized forward‐scattered light from solutions of rat tail collagen has been studied by photon correlation spectroscopy. The measured autocorrelation function is seen to decay on two widely different time scales. The decay time for the fast component is consistent with the rotational diffusion of rodl…
Summary Classical clay mineralogy determinations and electron microprobe analyses of weathering minerals developed in altered two-mica granites indicate that the chemical forces that produce new minerals are often constrained to small volumes, frequently on the scale of a mineral grain or contact between two grains in…
Laboratory heats of ten wrought steels containing 0 to 2.5% Mo and 0.035% Cb and commercial AISI 4130 steel were tested for mechanical properties and sulfide stress cracking (SSC) resistance in the quenched-and-tempered condition. The steels, representing molybdenum variations of columbium modified AISI 4130-type stee…
Abstract Poly(tetramethylene terephthalate) (PTMT) undergoes a reversible stress‐induced crystal‐crystal phase transition. X‐ray fiber‐diffraction photographs were obtained from the oriented, unstressed (α) phase. Relative intensities were measured from these photographs. These were used to help check the reported str…
Abstract The diffusive permeability coefficient to water for the polymer/EBBA composite membrane reveals a distinct jump in the vicinity of the crystal-liquid crystal phase transition temperature of EBBA. The permeability coefficients to hydrocarbon gases increase 100∼200 times over several degrees in the phase transi…
During traumatic regeneration of Planaria Polycelis tenuis, determination of serotonin, noradrenaline and dopamine levels revealed important variations of serotonin and catecholamines from the time of excision. The use of specific inhibitors of these hormones delayed regeneration whereas simultaneous addition of an ho…
The monovacancy formation enthalpy in copper, H 1v F =(1.30+or-0.05) eV, has been measured using precision electrical resistometry on samples quenched from temperatures in the range 525-650 degrees C. Comparison of this value for H 1v F with the activation enthalpy for self-diffusion via a monovacancy mechanism in cop…
Packing patterns in lanthanide–edta complexes: crystal and molecular structures of sodium triaqua(ethylenediaminetetraacetato)dysprosate(III) pentahydrate and caesium diaqua(ethylenediaminetetraacetato)ytterbate(III) trihydrate
Experiments were performed to determine susceptibility of 90/10 and 70/10 Cu-Ni alloys to sulfide induced corrosion as related to sulfide concentration, sea water velocity, and duration of sulfide exposure. All exposures were conducted in fresh sea water, and the range of experimental variables included sulfide concen…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOne-electron reduction of aromatic nitrogen heterocycles in aqueous solution. 2,2'-Bipyridine and 1,10-phenanthrolineQ. G. Mulazzani, S. Emmi, P. G. Fuochi, M. Venturi, M. Z. Hoffman, and M. G. SimicCite this: J. Phys. Chem. 1979, 83, 12, 1582–1590Publication Date (Print):Ju…
The nematic-smectic transition in the system of completely aligned hard cylindrical rods is investigated, by making use of the method of symmetry breaking potential. In the second virial approximation the transition is found to occur in the 3-dimensional system but not in the 1- and 2-dimensional systems, in contrast…
Superstructures of submonolayer films of indium on a clean silicon (111)7 surface have been investigated using techniques of molecular-beam deposition and reflection high-energy electron diffraction. A two-dimensional phase diagram including four superstructures, 7, (3)1/2, (31)1/2, and 4×1, are presented at substrate…
The structure—property relationships of (AB)n type segmented copolymers and methods of characterization are reviewed. The two-phase microstructure exhibited by segmented elastomers, resulting from thermodynamic incompatibility of the unlike blocks, is seen to depend on segment type, segment length, segment compatibili…
Abstract Two bands attributed to intrinsic defect states have been identified through studies of the infra-red and Raman spectra of pristine and neutron-irradiated vitreous (v-) SiO2. Vibrations in the 900–950 em−1 regime are assigned to non-bridging oxygen atoms (C1-) in agreement with previous studies. It is demonst…
Abstract Several series of alkali (sodium and potassium) aluminophosphate glasses were prepared with compositions of 32–63 mol % of P2O5 and the properties of these glasses were determined. In the glasses with a higher P2O5 content (P2O5\gtrsim42.5 mol % in the Na2O–Al2O3–P2O5 glass and P2O5\gtrsim45 mol % in the K2O–…
ABSTRACT Navicula ulvacea (Berkeley ex Kütz.) P. T. Cleve, a marine colonial blade‐forming diatom originally discovered in Scotland was collected at North Rustico, Prince Edward Island, during winter 1971. It formed dense stands of Porphyra‐ like fronds, ranging up to 60 mm long × 20 mm wide. These occurred under ice‐…
The new compound K 5 CuSb 2 crystallizes in the space group R3̄m with the constants a = 591(2) pm, c = 2814(4) pm, c/a = 4.76. There are linear (Sb-Cu-Sb) 5- groups in the structure which are isoelectronic to the HgCl 2 molecule.