Materials Literature
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Pyran (divinyl ether-maleic anhydride) copolymer (NSC 46015) is a polyanion with interferon-inducing and macrophage-stimulating properties, and therefore it has been studied as a possible antitumor agent. Extensive studies using pyran as an adjuvant to chemotherapy against the LSTRA murine leukemia and the Lewis lung…
Following a major shortage of 99Mo in the 2009–2010 period, concern grew that the aging reactor production facilities needed to be replaced. Most producers were using highly enriched 235U (HEU) as the target material. The Organisation for Economic Co-...Read More
A review is given of the experimental and theoretical data on ferromagnetic and antiferromagnetic semiconductors. Information on the magnetic, electrical, and optical properties is analyzed systematically. The main theoretical ideas on the physics of magnetic semiconductors are given without detailed proof and are use…
Cavitation bubbles were produced by focusing giant pulses of a Q -switched ruby laser into distilled water. The dynamics of the bubbles in the neighbourhood of a solid boundary were studied by means of high-speed photography using a rotating-mirror camera with framing rates of up to 300000 frame/s. Bubble motion was e…
Inelastic light scattering is used to study the dynamics of an ordered suspension of macromolecules.Received 4 August 1975DOI:https://doi.org/10.1103/PhysRevLett.35.1448©1975 American Physical Society
The elastic constants (in units of 10 11 dyn cm -2 ) of Na beta -alumina as measured by inelastic neutron scattering are c 11 =33.8, c 33 =24.5, c 44 =5.0 and c 12 =14.3, c 44 varies with the substitution of other ions for Na, with c 44 =5.6, 6.2 and 7.3 for Ag, K and Rb respectively. A dispersionless phonon mode obse…
The optical absorption and luminescence spectra of chromium ions in the LiGa 5 O 8 spinel are investigated. Measurements are made in the temperature range 1.6-300K. The absorption spectra consist of broad (split into three) spin-allowed bands connected with the transitions 4 A 2 to 4 T 2 and 4 A 2 to a 4 T 1 , and sha…
Four different n>or=4 component Hamiltonians describing phase transitions in certain physical systems are derived. The corresponding critical behaviour is studied using the exact renormalization group in d=4- epsilon dimensions. In particular, although TbD 2 , Nd and K 2 IrCl 6 have different symmetries, their critica…
13C relaxation parameters, T1, line width, and NOE, have been determined for backbone carbons of ligamentum nuchae elastin swollen by 0.15 M NaCl, 0.15 M NaCl-formamide, 0.15 M NaCl-ethanol, dimethyl sulfoxide, and formamide. The data have been analyzed in terms of (a) a single correlation time model and (b) a model e…
Primary amines react with 2,4-pentanedione at pH 6-9 to form enamines, N-alkyl-4-amino-3-penten-2-ones. The latter compounds readily regenerate the primary amine at low pH or on treatment with hydroxylamine. Guanidine and substituted guanidines react with 2,4-pentanedione to form N-substituted 2-amino-4,6-dimethylpyri…
A triple-coincidence, five-parameter technique was employed to search for two-photon emission in the decay of the $^{16}\mathrm{O}$(6.05-MeV) state. Data were event-recorded and analyzed in parallel with events associated with decay of the $^{16}\mathrm{O}$(6.13-MeV) and the $^{16}\mathrm{O}$(7.12-MeV) states. Our mea…
Experimental results are given of the dependence of work hardening parameters (critical shear stress, τc, work hardening coefficient, θA, and stage length ϵA at easy glide) in Mg crystals under basal slip on the density of pyramidal dislocations ϱf of various kinds. A relation between the kind of basal–pyramidal dislo…
The formation of vacancy-type dislocation loops in tungsten specimens as produced by irradiation with 60 keV Au ions is investigated by transmission electron microscopy. The majority of the loops is found to have Burgers vectors b=1/2〈111〉 and loop planes normal to n ≈︁ {110} (∢(b, n) ≈︁ 35°). The 12 different loop or…
The low-frequency Raman spectrum of a single crystal of NaN${\mathrm{O}}_{3}$ has been measured for temperatures from 25 to 300\ifmmode^\circ\else\textdegree\fi{}C covering both ordered and disordered phases. The crystal is partially disordered below the transition temperature and the corresponding Raman spectra are i…
EPR studies of x-ray damaged crystals of (NH4)2SO4 show that long lived defects, NH3+ ions, are produced in two inequivalent sites with each site having two magnetically inequivalent orientations. All sites have approximately the same isotropic hyperfine splittings which are found to be 19.0 G for nitrogen and −24.6 G…
Measurements are reported of the frequency dependence of the conductivities σ⊥ and σ∥ in some nematic liquid crystals with strong positive dielectric anisotropy which are nematic at room temperature. The conductivity relaxation which causes σ∥ to increase already at frequencies <100 Hz in highly deionized liqui…
Thermal-conductance measurements on thin Mylar and glass plates indicate that abrasion of the plate surfaces does not suppress specular reflection of phonons, contrary to the behavior in crystalline materials. This reinforces the suggestion that nonspecular reflection at crystal surfaces is caused primarily by lattice…
The phonon dispersion curves, the temperature dependence of the Debye temperature, and the static elastic, dielectric, and piezoelectric constants of $\ensuremath{\alpha}$-Si${\mathrm{O}}_{2}$ have been calculated from a modified rigid-ion model with an effective charge, with short-range central forces for the two Si-…
We have measured the Young's modulus and internal friction in the two-dimensional layered dichalcogenides $2H$-Ta${\mathrm{Se}}_{2}$ and $2H$-Nb${\mathrm{Se}}_{2}$ using a vibrating reed technique. Weak elastic anomalies are observed at the incommensurate charge-density-wave transitions in Ta${\mathrm{Se}}_{2}$ and Nb…
A method is reported for the determination of the surface recombination velocity by scanning electron microscopy; this method is based on an established relationship between the effective diffusion length of the minority carriers, the penetration depth of the electron beam, and the surface recombination velocity. Valu…