Materials Literature
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Glutamate racemase has been purified more than 12,000-fold from Lactobacillus fermenti. The racemase gene has been cloned using standard hybridization techniques combined with a novel selection for in vivo glutamate racemase activity, and the racemase has been expressed in Escherichia coli as 20-25% of the total solub…
The occurrence of alternative structures for the lithium, sodium, and potassium salts of poly(dG-dC) was determined as a function of hydration using IR spectra of nonoriented gels. Poly(dG-dC).K with added KCl (r = 0.56 where r is the moles of KCl per mole of nucleotide residue) gave results essentially identical to t…
Abstract A compatibilization strategy for poly(ethylene terephthalate) (PET) and polyethylene (PE) blends to achieve high toughness is described. Maleic anhydride functionalized styrene–ethylene–butylene–styrene (MA‐ g ‐SEBS) block copolymer at 20 pph was found to produce an intricate multidomain morphology in which t…
On macroscopic length scales observable by naked eye, or even on the scale of a few microns accessible with optical microscopes, the most prominent feature of dynamic wetting is the wetting line where the advancing fluid/fluid interface seems to intersect the solid surface at a measurable dynamic contact angle 9/). Fi…
Near-edge- and extended-x-ray absorption fine structure measurements, as well as luminescence excitation and emission spectra, were obtained from samples of porous Si and siloxene. Combined, these data establish that, contrary to a recently proposed explanation, siloxene is not generally responsible for the observed r…
We have discovered that a thin film of SiO2 can be directly reduced to Si under electron beam irradiation. The application of this effect to the fabrication of nanometer-sized Si dots and wires is demonstrated. In particular, if SiO2 is irradiated with a high intensity 100 keV electron beam of nanometer scale, then a…
The long wavelength hydrodynamics of films with unidirectional translational order adsorbed on fluid surfaces (as in a Langmuir monolayer) is formulated. We find the hydrodynamic frequencies \ensuremath{\omega}(q)\ensuremath{\propto}(\ifmmode\pm\else\textpm\fi{} \ensuremath{\surd}3 -i)${\mathit{q}}^{14/9}$ ${\mathrm{c…
The incubation time (ti) for the onset of porous Si formation by stain etching in HF:HNO3:H2O was observed to be a strong function of dopant type and concentration. For B-doped p-Si, ti increased significantly with substrate resistivity (ρ), from ∼0.5 min for 0.004 Ω cm to ∼9 min for 50 Ω cm. P-doped n-Si substrates e…
The authors present detailed investigations of vibrational modes in a hierarchy of rational (or commensurate) approximants to icosahedral quasicrystals based on exact diagonalization of the dynamical matrix and recursion calculations of the vibrational spectrum. The results demonstrate the existence of well defined lo…
Fragmentation of the actin binding glycolytic enzyme, aldolase, with cyanogen bromide yields an 18K actin binding fragment which corresponds to residues 1-164 of the aldolase sequence. Within this fragment there is a region of sequence (residues 32-52) which is highly homologous to a region of sequence near the C-term…
Photoemission spectroscopy was used to compare the effects of a hydrogen or argon plasma on natural-type 2B diamond (111) surfaces, while the diamond was heated to 350 °C. After the hydrogen plasma the surface exhibits a negative electron affinity, indicative of a hydrogen-terminated surface. In contrast, the argon pl…
Thin films of bismuth titanate, Bi4Ti3O12, prepared by the metalorganic solution deposition technique and rapid thermally annealed at 700 °C for 20 s have shown good ferroelectric switching, fatigue, and retention characteristics. A switching time of 180 ns was measured for a 0.5 μm thick capacitor with an electrode a…
The size effect on the ferroelectric phase transition in PbTiO 3 ultra-fine particles is reported. Samples with particle sizes from 20 to 200 nm were prepared by a sol-gel process followed by calcining at different temperatures. The particle size was determined by X-ray diffraction from the integrated width of diffrac…
We show that the 2p core-level line shapes of transition metal (TM) compounds are strongly influenced by the presence of more TM ions. Using calculations of clusters, involving more than one TM ion we explain the double peaked main line of the Ni 2p spectrum of NiO as well as the difference in line shape compared with…
Proton NMR second moment, spin—lattice relaxation times, spin-echoes, and DSC studies are performed for polycrystalline tetrabutylammonium bromide over a wide range of temperature. Two solid-solid phase transitions, a very weak and a strong one, are located at 305 K (III ⟹ II) and 362 K (II ⟹ I), respectively. Methyl…
Electrical and photovoltaic effects observed with a thin film of 5,10,15,20-tetra(4-pyrydil)21H,23H-porphine (TPyP) sandwiched between indium-tin oxide (ITO) and Al electrodes are explained in terms of the n-type semiconducting behaviour of the organic film and its formation of a blocking contact (Schottky barrier) wi…
[C 16 H 36 N] 2 °Mo 6 O 19 ] M r =1364.6, monoclinic, C2/c, a=16.280 (3), b=17.204 (3), c=17.738 (4) A, β=101.42 (2) o , V=4869.3 (17) A 3 , Z=4, D x =1.861 g cm -3 , λ(Mo Kα) = 0.71073 A, μ=15.66 cm -1 , F(000)=2728, T=298 K, R=0.0633 for 2857 observed reflections and 269 least-squares parameters. The six Mo atoms fo…
Beryllium calcium diborate, CaBeB 2 O 5 , M r =150.71, monoclinic, P2 1 /n, a=5.167 (2), b=3.756 (2), c=17.160 (2) A, β=98. 12 (2) o , V=329.7 (2) A 3 , Z=4, D x =3.036 g cm -3 , λ(Mo Kα)= 0.71069 A, μ=17.38 cm -1 , F(000)=296, T=298 K, R=0.039 for 508 reflections having F o 2 ≥3σ(F o 2 )
The electrical conductivity and thermoelectric power have been measured to investigate the semiconductor-metal transition in liquid Ge 15 Te 85 . It has been found that the activation energy of the electrical conductivity has a marked peak definitely below the temperature where the specific heat, compressibility and t…
Two competing theories of the optical absorption edge of intrinsic crystalline silicon, the indirect transition theory, and the recent disorder (Urbach edge) theory, are assessed critically. The assessment of the indirect transition theory includes an attempt to predict, by the use of the luminescence spectrum and the…