Materials Literature
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High-amplitude radial pulsations of a single gas bubble in several glycerine and water mixtures have been observed in an acoustic stationary wave system at acoustic pressure amplitudes on the order of 150 kPa (1.5 atm) at 21–25 kHz. Sonoluminescence (SL), a phenomenon generally attributed to the high temperatures gene…
Using both empirical potentials and first-principles total-energy methods, we have examined the energetics and elastic properties of all possible graphitic tubules with radii less than 9 \AA{}. We find that the strain energy per carbon atom relative to an unstrained graphite sheet varies as 1/${\mathit{R}}^{2}$ (where…
Abstract The National Institute of Standards and Technology (NIST) has made available the second version of the NIST X‐ray Photoelectron Spectroscopy Database. This paper reports on recent upgrades to the database to make the information more up‐to‐date and to make data searching and display more convenient and effici…
Abstract The life cycle of Aulacoseira subarctica (O. Müller) Haworth in Lough Neagh, Northern Ireland, is described. Cell numbers can reach up to 17000 per millilitre in spring. Most cells sediment to the bottom after silica limitation and go into a resting state during summer. The inoculum in autumn partly comes fro…
Some general aspects concerning dianions are discussed. The small LiF 3 2- and related XY 3 2- free dianions are predicted to be stable long-lived species. Quantitative results are given and the findings are illuminated by drawing a connection with crystals.
Total cross sections have been measured for electron scattering on H 2 and N 2 in the 4-300 eV energy range utilizing a linear attenuation technique. The present results are compared with existing experimental data of other groups in this energy range where good agreement with other experimental data is found.
The status of the knowledge on the mechanisms of multiple captures by a highly charged ion colliding with an atom is reviewed. The various and complementary techniques are first described, including energy gain spectroscopy, electron and photon spectroscopy with a particular emphasis on the rapidly developing techniqu…
Abstract Cellulose cinnamates with degrees of substitution ( DS ) of up to 2.3 were prepared by a reaction of cellulose with cinnamoyl chloride in pyridine. The cellulose cinnamate was found to form a cholesteric liquid crystalline phase at the concentrations higher than a critical concentration in some organic solven…
The OH stretch mode of hydrogen defect ensembles in cubic and tetragonal ${\mathrm{SrTiO}}_{3}$ and ${\mathrm{KTaO}}_{3}$:Li has been investigated with polarized Raman scattering. Introducing the Raman behavior type analysis to tetragonal crystals allows the determination of the local symmetry and proves for ${\mathrm…
Abstract Glassy polymers undergo relatively rapid physical aging just below their glass transition temperatures that can lead to embrittlement of normally tough materials like polycarbonate (PC). One approach for solving the embrittlement problem is to incorporate an impact modifier that can cause toughening when the…
The luminescence decay of excitons in disordered low-dimensional semiconductors with quantum confinement is shown experimentally to be characterized by a nonexponential profile and an absence of spectral diffusion. We are able to describe this luminescence as a hopping-assisted recombination using the correlation func…
Recently, it has been demonstrated that semiorganic materials have potential for very efficient nonlinear optical devices. Among many recently reported materials is zinc tris thiourea sulfate. We report measurements of the electro-optic, piezoelectric, and dielectric constants of this new material.
Blue upconversion laser operation in Tm:YLiF4 at 450.2 nm on the 1D2→3F4 transition, and at 483.0 nm on the 1G4→3H6 transition has been achieved using cw pumping with Ti Sapphire and DCM dye lasers. The 450.2-nm laser was excited by sequential two-photon absorption with 784.5-nm and 648-nm laser sources and was operat…
This highly illustrated monograph provides a comprehensive study of the structure and function of proteins, nucleic acids and viruses using synchrotron radiation and crystallography. Synchrotron radiation is intense, polychromatic and finely collimated, and is highly effective for probing the structure of macromolecul…
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We report measurements of the phase-slip process by which charge-density-wave (CDW) current is converted to single-particle current at electrical contacts. An excess voltage ${\mathit{V}}_{\mathrm{ps}}$ produces a large static deformation of the CDW phase, which drives formation of dislocation loops. Measurements of t…
We report the preparation of silicon-based visible light-emitting diodes, configured as heterojunctions between porous silicon (formed by electrochemical etching of p-type silicon wafers), and n-type indium tin oxide (ITO). The transparent ITO film allows light emission through the top surface of the device, under a f…
A model for ion transport in glass is presented which is based on the experimental evidence that cations in glass create and maintain their own characteristic environments. By postulating the existence of a site memory effect, we are able to visualize the formation of conducting pathways. We develop a quantitative the…
Abstract The compatibility of epoxidized poly( cis ‐1,4‐butadiene) (EPB) with chlorinated polyvinylchloride (CPVC) was investigated. Blends studied covered the complete composition range using EPB at two degrees of epoxidation: 20 and 43 mol % oxirane units. Tensile properties of EPB (63)/CPVC were also studied at the…
We find that tetragonal B${}_{5}$${}_{0}$N${}_{2}$ is stable against decomposition into BN and B${}_{1}$${}_{2}$, that the calculated lattice constants are in excellent agreement with the x-ray data, and that the atomic positions within the unit cell agree in general with the x-ray data but differ in detail due to dis…