Materials Literature
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The synthesis, phase properties and electro-optic response of two new chiral low molar mass organosiloxane liquid crystalline materials are presented. The structure of the molecule contains a short (three silicon atoms) siloxy chain attached via a hydrocarbon chain to the non-chiral end of a chiral mesogenic moiety. T…
Abstract The previously unknown crystal structure of the basic lead nitrate Pb 2 (OH) 3 (NO 3 ) has been determined using single-crystal X-ray diffraction data (Mo-Kα radiation, CCD area detector). The compound is orthorhombic, space group Immm, with a = 8.314(2), b = 8.545(2), c = 17.210(3) Å (R1 = 2.78% for 940 ‘obs…
Abstract Neutron diffraction provides an experimental method of directly locating hydrogen atoms in proteins, and the development of the neutron imaging plate (NIP) became a breakthrough event in neutron protein crystallography. The general features of the NIP are reviewed. A high resolution neutron diffractometer ded…
Nanowires of magnetic metals (Fe, Co, Ho, Gd) have been synthesized inside the hollow interiors of single-wall carbon nanotubes (SWNTs) by filling SWNTs with precursor metal chlorides and subsequent reduction. SWNTs have been filled by either the melt-phase sealed-tube reaction or a solution-phase method. Among the me…
Single-walled carbon nanotubes prepared by disproportionation of CO over Co-Mo/SiO2 catalysts have been characterized by Raman spectroscopy, using several excitation energies. By varying the reaction temperature, different ranges of nanotube diameter were obtained. The average diameter of a single-walled nanotube prod…
Features of the diffuse phase transition in lead barium niobate (PbxBa1−xNb2O6–PBN) ferroelectric ceramics are presented and discussed. Ceramics were prepared near to the morphotropic phase boundary (x∼0.63) and the dielectric properties were investigated. The character of the ferroelectric phase transition was carefu…
Sphingomonas sp. A1 possesses a high molecular weight (HMW) alginate uptake system composed of a novel pit formed on the cell surface and a pit-dependent ATP-binding cassette (ABC) transporter in the inner membrane. The transportation of HMW alginate from the pit to the ABC transporter is mediated by the periplasmic H…
Abstract The combination of stroboscopic techniques and neutron diffraction can be used to study the kinetics of structural changes in condensed matter on a microscopic level. Transient states may be identified and characterized on time-scales down to the microsecond regime. Hence, valuable information about the under…
Quantitative determination of the abundance of Si(nAl) tetrahedral structural units (where n = 0, 1, 2, 3, or 4) through analysis of 29 Si magic angle spinning nuclear magnetic resonance (MAS NMR) spectra was used to assess the state of Si-Al disorder in the zeolites analcime [(NaAl) x Si 48-x O 96 ·16H 2 O], chabazit…
The electrical behavior of NaNbO 3 ceramic samples with different relative densities was investigated by ac impedance spectroscopy in a range of 13 MHz to 10 −3 Hz between 400° and 800°C in dry air. Measurements were performed during heating and cooling cycles. The Nyquist impedance diagrams of dense sodium niobate ex…
The phase equilibria of the ternary Al-Cu-Fe system are demonstrated as isothermal sections at 800, 700, 645, 620, 617, 600, 592, and 560 °C. These data are based on metallographic investigation, microscopy with polarized light, and on structure analysis using X-ray diffraction, as well as on isopleths, which were con…
Abstract A series of heptanuclear rare‐earth‐centered trigonal prism clusters [LnCu 6 (μ‐OH) 3 (HL) 2 (L) 4 ]·(ClO 4 ) 2 ·25H 2 O (Ln = La−Ho and Y; H 2 L = iminodiacetic acid) was synthesized and their crystal structures were determined by X‐ray diffraction. The rare‐earth center and the copper ions are bridged by th…
A coating approach for synthesizing 0.9Pb(Mg 1/3 Nb 2/3 )O 3 –0.1PbTiO 3 (0.9PMN–0.1PT) and PMN using a single calcination step was demonstrated. The pyrochlore phase was prevented by coating Mg(OH) 2 on Nb 2 O 5 particles. Coating of Mg(OH) 2 on Nb 2 O 5 was done by precipitating Mg(OH) 2 in an aqueous Nb 2 O 5 suspe…
A local strain of the pennate diatom Pinnularia cf. “ nobilis ” was investigated using cytochemistry and fluorescence and EM techniques. The regular perforation of the chloroplasts of P. “nobilis” and the lack of a typical diatom pyrenoid were confirmed at the ultrastructural level. Cavities and channels in the comple…
Abstract The crystal structure of sahlinite [Pb 14 (AsO 4 ) 2 O 9 Cl 4 ] from Lågban (Sweden) has been refined up to R = 0.071 using single-crystal diffraction data collected at the Elettra synchrotron facility. Sahlinite is monoclinic, space group C2/c, with a = 12.704(4), b = 22.576(5), c = 11.287(4) Å, β = 118.37(3…
Two unpromoted Mo/γ-Al 2 O 3 catalysts containing almost the same amount of Mo were prepared using equilibrium deposition filtration, EDF, for depositing Mo-oxo species on the alumina surface at two different pH values (3.9 and 6.3). On these samples the same amount of Co ions was deposited by dry impregnation and thu…
A Ni 0 (15 wt %)/Al 2 O 3 catalyst is prepared by impregnation using [Ni(en) 2 (H 2 O) 2 ](NO 3 ) 2 as precursor salt containing the chelating ligand ethylenediamine (en). Due to the low solubility of this salt and the high viscosity of its solution, large crystals of the salt deposit on the support, clogging the poro…
Different spliced yam properties (strength, bending, abrasion, and appearance) are merged into a single score, also known as the total score, which is then used to analyze the overall performance of the yarns. A regression model and neural network model are set up according to the total score to predict the performanc…
This article presents a very simple process to align macroscopic quantities of single-wall carbon nanotubes (SWNT), the alignment being controlled by x-ray diffraction. A pellet of SWNT is obtained by pressing a raw nanotube powder up to a pressure of 10 kbars. A detailed study of the most characteristic lines in the…
Abstract New water‐soluble peroxo complexes of niobium( V ) with polyaminocarboxylic acids (PAC) have been prepared and characterized by IR and NMR ( 1 H, 13 C, 15 N) spectroscopy, as well as by thermal analysis. The synthesis in presence of excess H 2 O 2 leads to the oxidation of the nitrogen atoms of the PAC ligand…