Materials Literature
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A possibility of the formation a self-contained cylindrical lattice under crystallization of proteins due to the anisotropic (trapezoidal) shape of their globules is discussed theoretically. The theory of cylindrical crystallization is considered. It is shown that in this case the list of the low-symmetry phases is co…
Abstract The reaction of Te, TeX 4 and BiX 3 [X = Cl, Br] in sealed, evacuated glass ampoules in the temperature range 170° 100°C yields a variety of compounds composed of tellurium polycations and halobismutate anions. Two of these have been identified by crystal structure analyses as Te 4 [Bi 6 Cl 20 ] (triclinic, P…
Measurements of the solute distribution between nodules and of the tensile properties at two different levels in a 25 mm keel block of a ductile iron of composition 3.39%C, 2.56%Si, 0.25%Mo, 0.29%Cu and 0.37%Mn after hipping and austempering and after austempering at 375 °C are reported. A significant drop in tensile…
Abstract This study—based on Monsanto Rheometer measurements, determination of bound rubber, enthalpy of reaction, solvent swelling studies, and measurement of physical properties— revealed that the functional groups of intermediate super abrasion furnace (ISAF) carbon black chemically interact with the epoxidized nat…
A simple conductimetric system to determine ammonia concentration using a sensor based on a conductor polymer was developed. The sensitive element to ammonia is a thin polyaniline film deposited by chemical synthesis in an acrylic substrate prepared before hand with two graphite electrodes. The conductance of the poly…
Crystals of antithrombin were grown both on earth and in microgravity aboard US Space Shuttle Flight STS-67. The quality of crystals grown in both environments was highly variable and many could not be indexed. The microgravity crystals, however, generally diffracted better, as demonstrated by a novel procedure that e…
Abstract We have found, within the polyester family, interesting and potentially useful patterns of three‐component compatibility. The bacterially produced biodegradable polyester, poly(hydroxybutyrate) (PHB) and its copolymers with hydroxyvalerate (HV) together with polymers such as cellulose acetate butyrate (CAB),…
Electron paramagnetic resonance (EPR) has been used to investigate defects in hexagonal boron nitride (BN), polycrystalline cubic BN, BN and BN: C films produced by reactive sputtering. The dominant paramagnetic centre is attributed to the N vacancy. The Epr relaxation parameters have been deduced from the saturation…
The heat capacity for wurtzite-type BN has been determined between 50 and 300 K. The difference from that of zinc blende-type BN, which was also measured between 15 and 300 K, indicates that the interatomic force constants of the wurtzite-type lattice are generally 4% weaker than those of the zinc blende-type one. Thi…
The erosive efficiency of cavitating vortices is well known, although its exact mechanism has not been clarified. In order to bring fundamental information to the subject, a new device called “Cavermod” was designed in which axial collapse of a cavitating vortex is produced. We consider in this paper the design princi…
A new series of 2-(4- n -alkoxyphenyl)-5-(4-methylphenyl)pyridines (CH C H C H NC HOC H, n 1-10) (APMPP), which are teraryl compounds containing a pyridine ring in n 2 m 1 the centre position of the rigid core, was synthesized and the phase transitions of the homologues were studied using DSC measurements, polarizing…
Abstract Sulfur-cured non-reinforced SBR with different amounts of poly-, di- and monosulfidic crosslinks is devulcanized by high power ultrasound irradiation in a continuous process under various processing conditions. Total crosslink density, the proportion of polysulfidic crosslinks, gel fraction, and glass transit…
Abstract An electron microscopy technique which has been used to visualize the crosslinked regions in vulcanized blends of dry rubber has now been applied to films made from natural rubber (NR) latex. The method involves swelling the latex film with styrene, polymerizing the styrene, sectioning the sample and then sta…
Aluminum nitride (AIN) and alumina (Al 2 O 3 ) additives were blended into a high‐purity silicon nitride (Si 3 N 4 ) powder, and optimized processing conditions were applied for promoting a sintering process, which was shown to partly remove the amorphous silica‐rich (SiO 2 ‐rich) remains from grain boundaries. Such a…
Using dielectric spectroscopy in the frequency range 0.1 Hz-1.5 GHz, we investigated the dynamic properties of pentylcianobiphenyl (5CB) confined in porous matrices with randomly oriented, interconnected pores as well as in parallel cylindrical pores with different pores sizes. The confinement has a strong influence o…
As part of a programme to develop high-performance/high-temperature structural resins for aeronautical applications, imide oligomers containing pendent phenylethynyl groups were prepared, characterized, thermally cured and the cured resins evaluated as films, mouldings, adhesives and composites matrices. Initially a d…
Crushed rocks and mine tailings with K‐feldspar, biotite and nepheline as their main K‐bearing minerals were tested as K‐fertilizers in a pot experiment with barley. Equal amounts of K (as analysed by X‐ray fluorescence spectrometry) were added to each treatment before the start of the experiment. Three successive set…
The compounds Na(13)Cd(20)E(7) (E = Pb, Sn) were made in nearly 100% yield by quenching the melts of appropriate mixtures of elements sealed in niobium containers. They crystallize in the cubic space group Im&thremacr;, Z = 4, with a = 15.992(2) and 15.790(4) Å for E = Pb and Sn, respectively. The Cd/E part of the str…
The birch bark cherry, a Chinese tree that also grows in the State of Washington, has a remarkable set of properties. The horizontally peeling bark is semitransparent and very tough, with mechanical properties comparable to those of commercially important films such as Saran or Mylar.
We investigate light propagation through materials with both linear and circular anisotropy and find the relation of the amplitude and polarization transfer functions to the four anisotropic characteristics: linear circular birefringence, and linear and circular dichroism. We determine these four characteristics of an…