Materials Literature
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The pulse width modulation (PWM) inverter is widely used when voltage-frequency regulation is required. When laminated cores are energised by PWM voltage supplies additional losses occur due to flux distortion. The iron loss of three types of grain-oriented 3.25% Si-Fe toroidal cores was measured by means of a compute…
A Lyot-Ohman filter for imaging near the solar He i 1083-nm line is described. Fast and continuous spectral tunability is provided by nematic liquid crystals. This solid-state filter has a free spectral range of 2.35 nm and a spectral resolution of 0.135 nm at the operating wavelength of 1083 nm. A wide-fielded design…
A study of additional loss in an induction motor supplied by a PWM inverter is presented in this paper. The magnetic material used in the motor is characterized, thanks to a suitable Epstein measurement equipment, under several excitation conditions: sine and ideal PWM waveforms similar to the voltage delivered by the…
The effects of calcium and zirconium additions on the microstructures and mechanical properties have been investigated in the squeeze-cast ignition-proof magnesium alloys. The marked grain refining is achieved by the combined addition of calcium and zirconium because calcium promotes the dissolution of zirconium into…
A world-wide test program was undertaken by ASTM Task Group Gl.09.02.03 to assess the relative corrosivity of seawater at 14 test sites. Aluminum alloy 5086 (UNS A95086), 90/10 copper-nickel (UNS C70600), and copper-bearing carbon steel (UNS K01501) test specimens were prepared at one location, shipped to the various…
HETCOR NMR spectra reveal that previous assignments of the stereochemistry of poly(lactide) derived from rac and meso-lactide are incorrect; an alternative assignment is made at the tetrad level of resolution.
The cross-linking reactions and the decomposition processes of three different polysilazane precursors to silicon carbonitride have been investigated systematically in the course of pyrolysis to 1400 °C. The polymer to ceramic conversion chemistry was studied for the following precursors: (ViSiHNH) n (VS), (ViSiHNMe)…
The sensitized polymerization of synthetic lipid bilayers via visible-light irradiation of membrane-bound cyanine dyes is reported. Visible-light-initiated polymerizations were successful with liposomes composed solely or partly of either 1-palmitoyl-2-[10-(2‘,4‘-hexadienoyloxy)decanoyl]- sn -glycero-3-phosphatidylcho…
In situ silica reinforcement of styrene–butadiene rubber (SBR) vulcanizate has been achieved by the sol–gel reaction of tetraethoxysilane (TEOS) using n-butylamine as a catalyst. SBR was vulcanized with sulfur and soaked in TEOS and in an aqueous solution of the catalyst. When hydrochloric acid was used as a catalyst…
A simple method for studying the reactivity of hydrogen-terminated silicon surfaces via transmission FTIR spectroscopy is described. Abraded (100) single crystals of silicon, after etching in ammonium fluoride, show features in the IR spectrum that are assigned to Si–H stretching vibrations. Confirmation of the utilit…
Electron energy-loss spectra of VO 2 have been measured from perfect single crystalline areas of 100–180 nm diameter in the metallic and insulating phases. A sharp peak has been observed at 1.2 eV in the valence electron excitation spectra of the metallic phase but not in those of the insulating phase. We assign the p…
Chemical analyses of tourmaline crystals from a small pegmatite body, nearby the Stoihtte, Koralpe (Styria, Austria), exhibit a pronounced excess in boron, expressed by the simpli¢ed formula (Na0.43 Ca0.24&0:33) (Al2.43Li0.33&0:28)Al6(BO3)3(B1.23 Si4.87 O18)(O0.64(OH)3.36). A substantial substitution of silicon by bor…
Amino acids are transported with high fluxes through plasticized cellulose triacetate membranes containing large amounts of quaternary tetraalkylammonium salts; similar results are obtained using analogous polymer-supported liquid membranes.
This study was designed to assess a local drug delivery system of an anticancer agent, doxorubicin (DOX), using fibrin glue (Beriplast P) as a drug carrier. In vitro release of DOX from the fibrin glue was examined by a dialysis method in the presence and absence of sodium alginate. The in vitro mean dissolution times…
Abstract The Izod impact strength of poly(vinyl chloride)/methyl methacrylate/butadiene/styrene(PVC/MBS)polymer blends can be changed significantly with different levels of MBS and/or MBS particle size. The following results were obtained by investigating the fracture of PVC/MBS test specimens: (1) The dependence of t…
The solubility of carbon in liquid silicon equilibrated with silicon carbide was determined in the temperature range from 1723 to 1873 K. Silicon was melted in a silicon carbide crucible with an Ar-CO mixture gas flowing. Carbon in silicon was analyzed by the combustion-IR absorption method. The temperature dependence…
Eight different conducting polymer films formed from pyrrole and N-substituted pyrrole derivatives were characterized by cyclic voltammetry, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy. In particular, the XPS of poly[N-butylpyrrole], poly[N-(2-carboxyethyl)pyrrole], poly[N-(6-hydroxyhexyl)p…
Three new one-dimensional µ-nitrito nickel(II) complexes of formula [{NiL 1 (µ-NO 2 )} n ] [ClO 4 ] n 1, [{NiL 2 (µ-NO 2 )} n ] [ClO 4 ] n 2 and [{NiL 3 (µ-NO 2 )} n ] [ClO 4 ] n 3 have been synthesized and characterized [L 1 = N,N′-bis(2-amino ethyl)propane-1,3-diamine, L 2 = N,N′-bis(3-aminop ropyl)ethane-1,2-diamin…
Adsorption isotherms taken at temperatures ranging from 20 to 77 K show a large pore volume and surface area of 980 m2 g -1 for the physical adsorption of molecular hydrogen on MCM-41. The adsorbed hydrogen behaves more like a solid than a liquid and isosteric heats of adsorption reveal a heterogenous surface. The eva…
Reaction of [Mo 6 O 19 ] 2- with an excess of 2,6-diisopropylphenyl isocyanate (ArNCO) affords the title anion in which the hexamolybdate framework serves as an octahedral nexus for six terminal arylimido ligands.