Materials Literature
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We report on intensity-dependent photobleaching observed fully along the laser-pulse-propagating path as long as a few mm in bulk oxide glass containing colloidal silver particles. A likely mechanism for the photosensitivity is proposed in terms of two-photon ionization of silver particles in the glass, accompanied wi…
Poly(d,l)-lactide (PDLLA) homopolymer, with an average molecular weight of 20,000 daltons, was produced by the ring-opening polymerization of d,l-lactide in the presence of SnCl(2).2H(2)O as the catalyst. The PDLLA sponges loaded with chloramphenicol were prepared by a solvent evaporation technique. The drug loadings…
Abstract Tsugaruite, Pb 4 As 2 S 7 , is a new Pb-As sulphosalt from the Yunosawa mine, Aomori Prefecture, northern Japan. X-ray studies indicated it to be orthorhombic Pnn 2 or Pnnm , a 15.179(1), b 38.195(1), c 8.0745(1) Å, Z = 16 [Pb 4 As 2 S 7 ] with a subcell with c′ = 1/2 c . The six strongest diffractions in the…
Scanning electron microscope (SEM) images of holes or trenches obtained at high acceleration voltages, such as 200 kV, are analyzed by computer simulation. Secondary electrons generated by forward-scattered primary electrons (SE1s), and those by backward-scattered primary electrons (SE2s) are calculated separately, al…
Three new mixed oxides having the nasicon structure and containing arsenic(V) as tetrahedral ion were prepared and X-ray analyzed. The stoichiometry of the three phases can be expressed by the comprehensive notation MeZr 2 As (3− x ) P x O 12 where Me stands for Na + or K + , x equals to 0 and 1.5 when Me=Na, while x…
A microscopic theory is developed for the bulk and surface elastic constants of biaxial nematic liquid crystals. Our expressions depend on generalized orientational order parameters and on the direct pair correlation function.
Abstract A new double lithium rubidium sulphate, Li 3 Rb(SO 4 ) 2 · H 2 O, was found. Single crystals were obtained by drowning out in a tetramethoxysilane gel medium. The compound crystallises in the space group P 1 with parameters a = 5.1356(4) Å, b = 4.9853(4) Å, and c = 8.2712(9) Å, α = 90.032(7)°, β = 105.729(6)°…
Abstract Heating and cooling were found to affect the structure of carbon fiber polyphenylenesulfide‐matrix composites, as shown by their effects on the DC electrical resistance of the composite in the fiber direction. Matrix flow during first heating above T g and thermal stress buildup during cooling in any thermal…
Abstract Ionic motion and local structure of phenethylammonium ion (C 6 H 5 CH 2 CH 2 NH 3+ ) in a series of phenethylammonium lead(II) halides, [C 6 H 6 CH 2 CH 2 NH 3 ] 2 PbX 4 (X = Cl, Br, I) were studied by means of 13 C cross polarization/magic angle sample spinning (CP/MAS) NMR technique. Among the three salts,…
The transverse crack in thick plate welding is discussed with respect to deposited metal. In recent years, many of the new steel developments such as thermo-mechanical controlled process (TMCP) have been intended to improve weldability. When TMCP steel is used to achieve high strength with lean composition, the weld m…
Photoluminescence (PL) measurements on silicon samples implanted with radioactive Hg isotopes which decay fully or partly through the series Au/Pt/Ir are reported. Results obtained with 193Au isotopes (half-life 17 h) confirm earlier work concerning the involvement of Au in the 735 meV centre first observed in Fe-diff…
Abstract : A constitutive model for ceramics by Johnson and Holmquist has been incorporated and validated in the finite element computer program LS-DYNA2D. Using experimental data acquired at DREV, parameters for high density ceramics (around 98% theoretical maximum density) have been established. The effect of varyin…
A theoretical viscoelastic model based on the four-element Burgers model is devel oped to predict changes in load with time of ISO-301 stitched seams under longitudinal loading subjected to extension/recovery cycling at a constant rate of extension. Param eters calculated from experimental stress relaxation curves are…
Abstract Physical properties of polymers change with time. Exposure of amorphous polymers to high temperature will reduce their free volume, which in turn increases their heat distortion temperature and decreases their impact strength. Heat distortion additives, such as poly(α‐methylstyrene‐styrene‐acrylonitrile) (AMS…
The influence of P, As and Sb on the susceptibility to SCC of α-β′ brasses in different non ammoniated solutions was studied. Two series of brasses were tested: the first one with only 5 – 10% of β′ phase and the second one with 54 – 56% of β′ phase. The VB group elements were present at two different concentrations.…
Abstract We report on the recently developed method for the synthesis, optical, and structural properties of CdSe and CdTe nanocrystals. They were formed in aqueous solutions at moderate temperatures by a wet chemical route in the presence of thiol molecules as effective stabilizing agents. The size‐selective precipit…
The particular role played by the exchange interaction modulated by lattice vibrations (phonons) in effecting spin-lattice relaxation in amorphous materials in conjunction with the spin-orbit coupling, along with the role played by the well-known mechanisms, such as coupling to tunneling level states (TLS) via dipolar…
Abstract The high pressure phase behaviour of four liquid crystals, belonging to the class of laterally aryl‐substituted mesogens has been studied with differential thermal analysis. The pressure dependence of the phase transitions has been determined up to 300 MPa. Transition enthalpies have been determined with the…
Recently, Wingerchuk et al.1 described a patient with brain MRI lesions secondary to embolic metal fragments from a Bjork-Shiley heart valve prosthesis. The incidence and possible clinical symptoms of such lesions are unknown. We present another patient showing similar lesions on MRI who, in addition, had epileptic se…
The polyester in the base fabrics (PET) and the polyvinyl chloride coating (PVC) along with plasticizers and adhesive/glue were separated from a commercial coated fabric by a scheme of chopping, grinding, and extracting with a selected preferred aqueous MEK solution. A novel recovering method called swelling method is…