Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Small amounts of niobium (donor) doping in barium titanate (BaTiO 3 ) cause semiconductivity in this material. When the amount of niobium is increased slightly, the BaTiO 3 is converted back to an insulator. This phenomenon is attributed to donor segregation. Such an insulating material can recover its semiconductivit…
Small alterations in chemical composition, even within the boundaries of the international standards, can drastically alter the formation kinetics of intermetallic phases in a stainless steel. Therefore, by means of isothermal annealing experiments, the time-temperature-precipitation (TTP) diagram was constructed for…
Variable temperature X-ray diffraction (XRD) and real time Fourier transform infrared spectroscopy (FT-IR) were used to study the Brill transition of well crystallized Nylon 10 12 samples. The experimental data demonstrate that Nylon 10 12 undergoes Brill transition at about 120°C. IR spectra also show that a sequence…
Microstructural changes occurring during oxidation of the reduced form of donor‐doped BaTiO 3 (Ba 1− X D X . Ti 1− X 4+ Ti X 3+ O 3 ) and during reduction of the oxidized form of donor‐doped BaTiO 3 (Ba 1− X D X . Ti 1− X /4 4+ ( V Ti ) X /4 O 3 ) were studied using TEM. Samples of both types of solid solutions, con…
Using a broad-range pH indicator, the corrosion of Al and Al alloys in chloride-containing agar gels was studied. Distinct changes in pH were observed at low-pH anodic sites and at high-pH cathodes. There was a definite edge effect that occurred when gels were placed directly on the metal, which dominated the pattern…
Opalescent films, which own their color to Bragg reflection of light, can be prepared from cholesteric cellulose derivatives. Both lyotropic and thermotropic systems can be realised. Here we describe the manipulation of the wavelength of selective reflection by (a) mechanical compression, (b) photoisomerization of pen…
Abstract The 4‐environment generalized micromixing (4‐EGM) model is applied to describe turbulent mixing and precipitation of barium sulfate in a tubular reactor. The model is implemented in the commercial computational fluid dynamics (CFD) software Fluent. The CFD code is first used to solve for the hydrodynamic fiel…
We present a Stokesian dynamics (SD) computer simulation study of the static and dynamical properties of a monolayer of spherical colloidal particles restricted to diffuse in the midplane between two parallel walls. SD simulations account for hydrodynamic interactions (HI's) among the particles, and between particles…
The segmental ligand 2-(6-(N,N-diethylcarbamoyl)pyridin-2-yl)-1,1'-dimethyl-2'-(5-(N,N-diethylsulfonamido)-pyridin-2-yl)-5,5'-methylenebis[1H-benzimidazole] (L3) is synthesized via a multistep strategy that allows the selective introduction of an electron-withdrawing sulfonamide group into the ligand backbone and its…
Abstract A combinatorial library approach enables us to find new low molecular-weight organogelators composed of a bile acid–alkylamine salt; the gel phenomena are investigated by FT-IR spectroscopy, SEM, and X-ray crystallography.
Poly[3-(3‘,5‘-di- tert -butyl-4‘-acetoxyphenyl)thiophene] ( 1a ) was regioselectively synthesized via simple oxidative polymerization of 3-(3‘,5‘-di- tert -butyl-4‘-acetoxyphenyl)thiophene ( 2a ) with ferric chloride. Head-to-tail content of 1a with a molecular weight of >10 4 reached 96% by modulating both the polyme…
Bi-layered Aurivillius compounds prove to be efficient candidates of nonvolatile memories. SrBi2Nb2O9 thin films were deposited by excimer laser ablation at low substrate temperature (400 °C) followed by an ex situ annealing at 750 °C. The polarization hysteresis behavior was confirmed by variation of polarization wit…
The metastable state of an undercooled melt can provide access to the formation of metastable phases whose crystallographic structures differ from their stable counterparts. The electromagnetic levitation technique is used here to undercool bulk melts without containers. This technique, combined with energy dispersive…
Cubic BaTiO 3 powders have been synthesized from gel powders after thermal treatment in an alcohol solution and characterized using X‐ray diffractometry, transmission electron microscopy, and other techniques in detail. The borderline reaction conditions, such as the reaction temperature and time, for the synthesis of…
Four carboxymethyl cellulose samples derived from the synthesis concept of “reaction in reactive microstructures” were characterised in detail by combination of different analytical techniques. Fractionation of one of the samples according to water-solubility into four fractions revealed that a non-statistical distrib…
We studied composition, structure, and growth parameters of amorphous diamond-like carbon (DLC) and carbon nitride (CNx) films deposited by pulsed laser deposition in vacuum and in nitrogen atmosphere. The composition (0⩽N/C⩽0.4), the structural and the electronic properties of the deposited carbon and carbon nitride…
Silica (SiO 2 ) is found to react readily with ethylene glycol (EGH 2 ) to form neutral glycoxysilanes in the presence of catalytic amounts of high-boiling organic amines, such as triethylenetetramine (TETA), trishydroxymethyleneaminomethane [H 2 NC(CH 2 OH) 3, THAMH 3 ], and triethanolamine [N(CH 2 CH 2 OH) 3, TEAH 3…
The synthesis and crystallographic characterization of the five-coordinate iron(III) porphyrinate complex [Fe(OEP)(NO)]ClO4 are reported. This [FeNO]6 complex has a nearly linear Fe-N-O group (angle = 173.19(13) degrees) with a small off-axis tilt of the Fe-N(NO) vector from the heme normal (angle = 4.6 degrees); the…
OBJECTIVE: This study was designed to determine whether a mixture of iodinated contrast material and gadopentetate dimeglumine used during MR arthrography yields free gadolinium ion, a systemically toxic metal. MATERIALS AND METHODS: Mixtures of commercially available nonionic and ionic iodinated contrast agent, gadop…
The reactive pyrolysis−gas chromatography technique was applied to verify the branching and/or cross-linking structures in an industrially available PC sample and its thermally treated ones through identification of specific pyrolysis products directly reflecting the related abnormal structures. On the pyrograms of th…