Materials Literature
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Reaction of tetrachloropyrimidine (1) with pyridine resulted in the formation of a heteroaromatic tripole, the 2,6-bispyridiniopyrimidin-4-olate chloride (3), the structure of which was established by X-Ray crystallography.~m b e r l i t e ~ IRA-400 in its hydroxy form converted 3 into the corresponding stable hydroxi…
FTIR spectroscopy has been applied to study the adsorption and dehydrogenation of ethane on a silica-supported platinum (Pt/SiO2) catalyst with metal particles diameters mostly in the range 5–15 nm and with predominantly [111] micro-facets. At ca. 90 K, there is clear spectroscopic evidence for the formation of a firs…
Thermoelectric properties of Chevrel-type sulfides AMo6S8 (A=Fe, Ni, Ag, Zn, Sn, Pb, Cu) were investigated with respect to many advantageous characteristics of the Chevrel compounds for thermoelectric applications. The electrical conductivity, σ, was 102.5S·cm-1<σ<103S·cm-1 for most of the samples from room temperatur…
Syntheses of acenaphtho[1,2-b][1,4]oxathiine 4 and 8,9-bis(methylsulfanyl)acenaphtho[1,2-b][1,4]dithiine 5 are reported. The fairly persistent radical ions of acenaphtho[1,2-b][1,4]dithiine 1, acenaphtho[1,2-b][1,4]benzodithiine 2, acenaphtho[1,2-b]thieno[3,4-e][1,4]dithiine 3, and 4, i.e. 1˙+–4˙+ and 1˙––4˙–, were ge…
This paper presents the newest applications of silicone composite insulators which are finding increasing use not only in Switzerland, but also in the power industry worldwide. These applications include interesting designs for railway overhead lines, medium voltage lines, and 400 kV high voltage overhead transmission…
Urea-induced unfolding of Escherichia coli citrate synthase occurs in two phases, as monitored by circular dichroism at 222 nm (measuring secondary structure) or by tryptophan fluorescence. In this paper we characterize the intermediate state, which retains about 40% of the ellipticity of the native state, and is stab…
We present what we believe to be the first implementation of a Fabry-Perot (FP) etalon using polymer cholesteric liquid-crystal mirrors. These polymer mirrors have each been fabricated onto a single substrate, which allows the FP cavity spacing to be only a few micrometers wide. For the experimental results presented,…
The solution polycondensation of aromatic dithiols with activated aromatic dihalides like bis(4-fluorophenyl) sulfone with use of cesium fluoride as a base in polar aprotic solvents readily affords aromatic polysulfides having inherent viscosities as high as 1.0 dL/g. The polycondensation proceeds under essentially ne…
Three novel polyfluorinated cationic surfactants having a short perfluoroacyl group and double long alkyl chains, and three corresponding hydrocarbon analogues were synthesized. All of the surfactants formed small unilamellar vesicles in water upon sonication. The temperature conditions for the sonication were careful…
Money trees are artifacts dating from the Eastern Han dynasty (AD 25–220) which have been excavated from tombs in China. The branches of these trees are constructed of bronze, and contain images of coins along with figures important to Han beliefs. Samples from bronze branches originating from several different trees…
We have clarified the microscopic mechanism of the semiconductor-metal transition in liquid with increasing temperature and pressure by means of ab initio molecular-dynamics simulations. It is shown that, at higher temperatures, a major part of this liquid mixture consists of twofold chain-like structures, while, at l…
By employing a new strategy presented recently by Wulf etal., axisymmetric drop shape analysis (ADSA) can be used to determine simultaneously the surface tension and the density of polymer melts from sessile drops at elevated temperatures. This required the modification of the ADSA algorithm to replace the density by…
Titanium alloy (Ti-6Al-4V) and cast cobalt-chromium-molybdenum alloy (CoCr) have a long history of successful clinical use. However, a higher strength material would be useful to manufacture certain implants, such as smaller hip-stems, with more extensive porous-coating to facilitate improved fixation. A new grade [hi…
Abstract During the fall and winter of 1995, ninety-two samples were collected from twenty-three sampling stations in the Matanza-Riachuelo river basin. Epipelic diatoms and physico-chemical parameters were studied to establish water quality. Ecological methodologies (species richness, diversity and saprobity indices…
Nanoparticles, one of the colloidal drug delivery systems, hold great promise for reaching the goal of controlled drug delivery as well as site specific delivery. This review presents various methods of preparation, characterization, stability, drug release and applications of nanoparticles. If appropriately investiga…
2‐Dioctylamino‐1,3,5‐triazine‐4.6‐dithiol (DO) was found to electrochemically polymerize on AZ91 (magnesium alloy) plates. This method of plating metals is called "polymer plating." An aqueous solution was selected for the polymer plating of triazine dithiols on magnesium alloy plates as an effective electrolytic solu…
The crystal structure of a covalently cross-linked Lactobacillus casei thymidylate synthase has been determined at 2.8 A resolution. The sites for mutation to achieve the bis-disulfide linked dimer were identified using the disulfide modeling program MODIP. The mutant so obtained was found to be remarkably thermostabl…
A neutron diffraction study of the crystalline structure and magnetic state of LaMnO 3+ δ samples with different deviations from oxygen stoichiometry has been made at 4.2 K. It is shown that annealing at reduced oxygen pressure is accompanied by transformation of the magnetic structure from ferromagnetic, with magneti…
Lead zirconate titanate thin films with a seed layer were successfully deposited on platinized silicon substrates by a modified sol-gel processing using a new zirconium source. The seed layer between the platinum bottom electrode and the PZT films could promote formation of perovskite phase and enhance the crystallini…
The tetradentate bis(dithiolate) ligands 1,4-bis[(2,3-disulfanylbenzamido)methyl]benzene H4L1 and 1,7-bis(2,3-disulfanylbenzamido)heptane H4L2 were prepared and converted into the dinuclear titanocene complexes [(TiCp2)2(L1)] 1 and [(TiCp2)2(L2)] 2, respectively. A ligand transfer reaction of 1 and 2 with [NR4]2[CoCl4…