Materials Literature
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The trans cis photoisomerization and angular reorientation of an azobenzene derivative (DR1) in dye-doped polymer matrices [poly(methyl methacrylate)], induced by linearly polarized visible illumination (λ0=496.5 nm), were investigated by dichroism measurements in the visible region and by polarized resonance Raman ex…
Water absorption characteristics, and developments of transverse tensile modulus and strength, and mode II fracture toughness with water absorption of a unidirectional glass/polypropylene (PP) composite have been examined. Immersion times up to 5 months at 50°C were employed. Overall, very small amounts of water were…
The magnetoresistance measurements for the quasi-one-dimensional conductor ${(\mathrm{TMTSF})}_{2}$Cl${\mathrm{O}}_{4}$ have been performed over a wide temperature range in order to investigate the mechanism of the anomalous rapid oscillation (RO) behavior. The dependences of the RO's on the electric current and magne…
A new type of very-low-stiffness super-active composite material is presented. This laminate uses shape-memory alloy (SMA) filaments which are embedded within a low-hardness silicone matrix. The purpose is to develop an active composite in which the local strains within the SMA actuator material will be approximately…
Recent literature has drawn a distinction between charging across the surface (lateral differential charging) and charging with depth (vertical differential charging) for insulating samples. In this study, differential charging in a bulk insulator was investigated using imaging and small-area spectra acquired with a m…
Abstract The kinetics of radiolabeled poly(styrene sulfonate) adsorbing at a positively‐charged surface were determined using a surface‐charged plastic scintillator as substrate. In situ measurements indicate diffusion‐limited adsorption with the final adsorbance dependent on the solution concentration of polyelectrol…
A mixed-valent oxide-catalytic carbonization process for synthesizing monodispersed carbon spheres at very low cost is reported for the first time. The carbon spheres are formed by catalytic carbonization of natural gas (primarily methane) with the assistance of mixed-valent metal oxides. The catalyst is reusable and…
A significant feature for the atomic structure of the intermetallic compounds Co 2 Al 5 (hP28), monoclinic m-Co 4 Al 13 ( mC(102-7.2) [notation according to Parthé et al . (1993)] and orthorhombic o-Co 4 Al 13 (oP102) is the occurring of the filled pentagonal channels. Least-square refined lattice parameters as well a…
This paper analyses the structural properties of the δ-Al4Cu9 phase as an approximant to quasicrystals. The discussion is developed along two directions. One is the valence electron concentration (VEC) correlation; both the δ-Al4Cu9 and Al-Cu-Fe icosahedral phases are Hume-Rothery intermetallis with similar values of…
Introduction.Elements of Design.Design Methods.Loads and Stresses.Smooth Parent Material.Holes and Notches.Welded Joints.Mechanically Fastened Joints.Adhesive-Bonded Joints.Testing.Special Design Considerations.Codes and Specifications.S-N Data.Strain-Life Data.Crack-Propagation and Fracture-Toughness Data.Good Practi…
Multimode buried waveguides made in silicate glass by field- assisted ion exchange present very asymmetric profiles. We show how this phenomenon originates in the large dependence of the kinetics on the local ion concentrations. For this purpose, we derive an interdiffusion equation that includes the effects of concen…
Metal-free- and metallo-phthalocyanines (M = Ni or Zn) carrying four dimethylaminoethylsulfanyl-or trimethylaminoethylsulfanyl- groups on peripheral positions have been synthesized from the corresponding phthalonitrile derivatives in the presence or the absence of the anhydrous metal salt [NiCl2 or Zn(CH3COO)2]. The n…
A brief account of transformations of internal structure of hydrogen bonds, and transformations involving the breaking and formation of hydrogen bonds is highlighted for a selected group of crystals. The main stress is laid on the short bistable -OH‒O= hydrogen bonds, illustrating several general properties, often blu…
Abstract Many low viscosity, immiscible fluids are difficult to incorporate into polymer matrices because of thermodynamic immiscibility and a large mismatch of melt viscosities. In this investigation, a model system was used to determine the mechanisms and kinetics of mixing in such formulations. The model systems co…
The compounds SrPu 2 Ti 4 O 12 , Pu 2 Ti 3 O 8.79 , and Pu 2 Ti 2 O 7 , where plutonium is in the (III) oxidation state, were prepared and identified via X‐ray diffraction (XRD). The solid solubility limit of Pu 2 Ti 2 O 7 in Ln 2 Ti 2 O 7 (Ln = Gd, Er, or Lu) was also studied via XRD; it was determined that the solub…
Chromium oxide Cr 2 O 3 thin films were prepared by atmospheric‐pressure chemical vapor deposition (CVD) methods. For CVD from chromium hexacarbonyl, the lower limit of the reaction temperature was 150°C, which could be reduced to 60°C by irradiation with UV light. The films exhibited preferred overgrowth with a verti…
Structural changes in sol-gel derived amorphous silica films were investigated using vacuum ultraviolet light emitted from an undulator. A significant increase in the refractive index and a decrease in the thickness for the silica films were induced by photons with energies above ∼9 eV. The frequency shift of ω4 (tran…
Abstract This paper examines the mechanisms by which a polymer is dispersed in a co‐rotating twin‐screw extruder. An experimental investigation of the morphological evolution has been carried out on a 45‐mm co‐rotating twin‐screw extruder. Polyethylene/polystyrene (PE/PS) blends in the low concentration range (i.e., 5…
We have identified three distinct membrane vesicle populations from sea urchin egg cytoplasm that cooperate in assembling the male pronuclear envelope in vitro. Membranes from sea urchin egg homogenates were separated by buoyant density into five vesicle fractions, three of which bind to demembranated sperm nuclei. Ea…
Abstract Pure 4,4′‐bis(2,3‐epoxypropoxy)biphenyl ( 1 ) has been synthesized and its mesophase behaviour has been investigated. 1 forms a monotropic nematic mesophase with a virtual clearing temperature of 109°C. 1 has been cured with 2,4‐diaminotoluene ( 3 ), 4,4′‐diaminobiphenyl ( 4 ), and 4‐aminophenyl 4‐aminobenzoa…