Materials Literature
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Abstract Cyanine dyes bound to α-helical poly(L-lysine·HBr) (PLL·HBr) in methanol provide extremely strong exciton couplings in CD spectra caused by their R-chiral dimer formation and that dyes-PLL complexes show varying degrees of remarkable strength change in the CD recognizing on their methylene numbers upon additi…
Emission and excitation spectra and luminescence decay times of the SrS:Sb 3+ and SrSe:Sb 3+ powder phosphors are studied over the temperature range from 2 to 372 K. The emission band at 293 K is located at 600 nm for SrS:Sb 2 S 3 (0.05 mol%) and at 633 nm for SrSe:Sb 2 S 3 (0.2 mol%). The excitation processes are att…
The hydrogenation disproportionation desorption recombination (HDDR) process has been established as an effective processing route for the production of isotropic NdFeB coercive powder. By the addition of very small amounts of zirconium to the initial composition, it has also been found that anisotropic powder can be…
The magnetic properties and synthesis of the magnetically hard strictly two element Sm/sub 5/Fe/sub 17/ phase were studied for sputtered film samples. Normally, bulk sample synthesis of this phase has required the substitution of at least 10 at.% of a transition metal, such as Ti for the Fe, to stabilize this phase. I…
Abstract Previously 90 MHz CW-NMR spectroscopy has been used to estimate the crosslink density in individual components of elastomer blends. Transfer of the technique to a 300 MHz FT instrument is not straightforward. Chemical shifts of polymer resonances in spectra of single-polymer vulcanizates are dependent on cros…
We have observed birefringent spirals induced by a field in a fingerprint texture of a cholesteric polymer in solution in a nematic low molar weight liquid crystal. This paper describes the conditions of nucleation of these spirals and the part of different parameters which determine their characteristics.
Abstract Two new types of liquid crystals, 5-(4-alkanoylaminophenyl)-2-alkanoylaminotropones and 5-(4-alkanoylaminophenyl)-2-alkanoyloxytropones, were prepared. The former showed the smectic A phase and the latter did the smectic A and C phases. The 1H NMR spectra indicated the former to be in intramolecularly hydroge…
Natural MoS2 was investigated by scanning tunneling microscopy operated in air. The atomic resolution image yields the hexagonal symmetry of the surface of the crystal with lattice constant of 3.1 Å, in agreement with the reported x-ray crystallographic value. Corrugations along the [110] cell diagonal show major and…
Full characterization of particulate recording media requires the modeling of both the reversible and the irreversible components of the magnetization. Experiments show that the height of minor loops originating from negative saturation is not an even function of the magnetization. A moving Preisach-type model with re…
Biocorrosion means any process of corrosion in wich microorganisms are somehow involved. As far as the petroleum industry is concerned, the anaerobic type is the more important, with Sulphate-Reducing Bacteria (SRB) accouting for half of the described processes. SRB are obligate anaerobs that use sulphur, sulphate or…
The heat capacities of liquid Li 2 SiO 3 and Li 2 Si 3 O 7 have been determined through drop calorimetry measurements to complement available data on lithium, sodium, and potassium silicate melts. The composition and temperature dependences of the heat capacity depends specifically on the nature of the alkali element,…
Frequency-dependent complex impedances were measured in Nb-doped (Ba 0.6 Sr 0.4 )TiO 3 PTC (positive temperature coefficient) ceramics. The complex impedance data were analyzed in Cole-Cole-type equivalent circuits by the computer fitting method in order to determine individual resistance and capacitance values of the…
We report a system capable of obtaining Raman spectra during growth of carbon films in a hot filament reactor. A gated, multichannel detection system was used to discriminate against the high levels of background radiation produced by the hot substrate and the hot filament. The ability to detect and distinguish betwee…
Starting from the necessity for an accurate background estimation for electron Compton scattering on solids (ECOSS) we investigated the contribution of multiple-scattering events to angle-resolved electron-energy-loss spectra at large momentum transfer. Plasmon excitation, elastic and quasielastic (i.e. phonon) scatte…
Abstract [(TMTAA)K 2 ] und [SmI 2 (thf) 2 ] reagieren in einer unübersichtlichen Redoxreaktion zu dem mehrkernigen Metallkomplex [K(thf) 3 ] 2 [(TMTAT) 2 Sm 2 ]. Der Aufbau dieser mit vier Molekülen THF pro Formeleinheit kristallisierenden Verbindung konnte durch eine Röntgenstrukturanalyse aufgeklärt werden (Raumgrup…
Nd/sub 16/Fe/sub 76/B/sub 8/ sintered magnets were heated in an open furnace for times up to 29 days. The results of scanning electron microscope (SEM) observations, quantitative EDX/WDX analysis, microhardness measurements and Mossbauer spectroscopy were found to be consistent with the Nd/sub 2/Fe/sub 14/B phase havi…
A model explaining the nature of ferromagnetic exchange in organometallic charge-transfer molecular stacks is presented. It arises because of both the weak delocalization of unpaired electrons occupying the acceptor sites and the ferromagnetic exchange interaction between slightly delocalized acceptor electrons and pe…
Multilayer ceramic decoupling capacitors fabricated using a barium titanate-based dielectric are used with the glass-ceramic/copper/polyimide substrates of the thermal conduction modules (TCMs) of the IBM Enterprise System/9000™ processors to suppress the voltage noise generated by the logic circuits of the semiconduc…
In this study we investigated the surface-enhanced Raman scattering (SERS) properties of p-nitroaniline, which is a potential chemical for use in optical disk coating(s) and also an important compound used as an intermediate or precursor in the manufacture of chemical agents, pesticides, pharmaceuticals, dyes, and ant…
The structural gene coding for the lysine-sensitive aspartokinase II of the methylotrophic thermotolerant Bacillus sp. strain MGA3 was cloned from a genomic library by complementation of an Escherichia coli auxotrophic mutant lacking all three aspartokinase isozymes. The nucleotide sequence of the entire 2.2-kb PstI f…