Materials Literature
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The mechanism of the rate determining step (r.d.s.) for dissolution of well characterised, very perfect MgO “smoke” crystals, has been re-evaluated by studies of the dependence of log (rate) on pH. Surface potential barrier modification is the most likely r.d.s. when solution diffusion is not limiting. Electron micros…
The 1978 proceedings of the American Association of Cost Engineers include papers on second unit scheduling concerns on a dual-unit nuclear project, the economics of energy transport via metallized iron ore, cost estimating for geothermal power systems, economics of long-distance coal slurry pipeline-methodology, and…
The hydrogen bond plays an all important role in determining the physical properties of a variety of classes of ferroelectrics and antiferroelectrics of which potassium dihydrogen phosphate (KDP), lithium trihydrogen selenite and Rochelle salt are examples. This role is evidenced by the usually large isotope effects o…
Several compounds with the pyrochlore structure have been investigated. Dielectric and structural studies of the compound Cd2NB2O6S show the existence of three phase transitions at 106°C, 184°C and 282°C. The ferroelectric properties have been studied by several methods (x-Ray, DTA, dielectric and dilatometric methods…
The presintered layer structure bismuth compounds of PbBi2Nb2O9, Na0.5Bi4.5Ti4O15, PbBi4Ti4O15 and Pb2Bi4Ti5O18 are hot-worked by press forging under the maximum load of 200 kg/cm2 at a temperature of 1000°C to 1200°C. The reduction ratio of height is more than 70%. The well-oriented polycrystalline samples with an or…
Absorption and magnetic circular dichroism (m.c.d.) spectra of the α polymorphic form of a series of phthalocyanines CH2Pc, CoPe, NiPc and CuPc have been observed between 12 000 and 40 000 cm–1. Band shape analysis of both the absorption and m.c.d. data reveals Davydov splittings in both the Q and B (Soret) bands and…
A comparison between the vibrational properties and stereochemistry of [Co(pc)(4Me-py)2] and [Fe(pc)-(4Me-py)2][pc = phthalocyaninato(2 –), 4Me-py = 4-methylpyridine] is carried out by using far-i.r. spectroscopy and X-ray diffractometry. The crystals of the two complexes, based on the packing of [M(pc)(4Me-py)2] addu…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSilicon Phthalocyanine-Siloxane Polymers: Synthesis and 1H Nuclear Magnetic Resonance StudyJohn B. Davison and Kenneth J. WynneCite this: Macromolecules 1978, 11, 1, 186–191Publication Date (Print):January 1, 1978Publication History Published online1 May 2002Published inissu…
The first photochemically generated, ‘cation-locked’ crown-ether is reported.
The crystal and molecular structure of the title complex has been determined from single-crystal X-ray diffraction data and refined to R 0.068 for 1 423 independent reflections. Four oxygen-bridged cubane-type molecules with a Cu4O4 core, having crystallographically imposed S4 point symmetry, occupy a tetragonal unit…
Corrosion of base metal alloys was studied by placing the alloys in artificial saliva for 2 months and then determining the concentration of metal ions in the saliva. The distribution of the attack on the surface was examined. The results indicated that the amount of metal ions in the artificial saliva could be relate…
Abstract Continuing pressures to reduce phosphates in wastewaters have sustained an intensive worldwide search to develop acceptable substitutes. Organic polycarboxylate salts have been most extensively investigated because there are a large number of structural possibilities, and the possibility for biodegradation to…
Partially purified glyceraldehyde‐3‐phosphate dehydrogenase (NADP) (EC 1.2.1.13) from Sinapis alba seedlings was filtered on Sephadex G‐200 in the presence of NADP(H) and NAD(H). With NADP(H) the enzyme elutes as a dissociated species ( M r ∼ 170 000), whereas with NAD(H) it travels as an aggregate in the void volume…
Abstract Polyacrylonitrile (PAN)‐containing graft copolymers of corn starch were prepared from monomer mixtures and then saponified, and dried. Incorporation of selected comonomers lead to shorter saponification times and higher yields of adsorbent products. Substitution of flour for starch gave products which had a h…
Abstract 1,3-Diorganyl-2,2-dimethyl-I,3,2,4λ 2 -diazasilastannetidines can be prepared as monomers (organyl = tert-butyl) or dimers (organyl = isopropyl) in nonpolar solvents, depending on the organic nitrogen substituent. The formation of the dimer, which is due to an intermolecular Lewis-acid-base interaction of Sn(…
Abstract Bei der mit Thiosemicarbazid umgesetzten Dialdehydstärke tritt ein gleichzeitiger Fixier‐ und Kontrastiereffekt erst bei der nachträglichen Behandlung mit Silbernitrat auf. Die Fixierung wird auf die durch freiwerdende Protonen begünstigte Bildung interchenarer Acetalbrücken zurückgeführt, die vornehmlich in…
Abstract The influence of the hydrodynamic environment on the growth phenomena of large potassium dihydrogen phosphate (KDP) crystals has been investigated in a three vessel system. Special attention was paid to the onset of inclusion formation. Flow visualization experiments carried out in a wind tunnel showed that t…
SummaryThe initial film growth and pore development sequences during the anodizing of aluminium substrates at constant current density in phosphoric acid have been observed by transmission electron microscopy of stripped anodic films and ultramicrotomed sections. Initial film growth proceeds by immediate film thickeni…
High resolution nuclear magnetic resonance (NMR) and ethidium bromide binding studies are used to demonstrate that poly d(G-T) forms an ordered double helical structure at low temperatures (below 24 degrees C in 0.3 M NaCl) in which G and T are hydrogen bonded together in a wobble base pair hydrogen bonding scheme as…
The first protonation site of [V10O28]6– differs both from the second protonation site and from the site of preferential interaction with aqueous manganese(II) ion. It is probably an out-of-plane apex, and not a bridging oxygen as has recently been proposed. The 51V n.m.r. linewidths are almost independent of direct p…