Molecular mobility in para-substituted polyaryls. 1. Sub-Tg relaxation phenomena in poly(aryl-ether-ether-ketone)
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Comparing Effects of Vacuum Annealing and Dry Oxidationon the Photoluminescence of Porous Si
Effects of vacuum annealing and dry oxidation on the photoluminescence properties of porous Si are reported. Anodized porous Si is formed by electrochemical etching in an aqueous HF solution of 16 to 48 wt% with a current density of 10 to 70 mA/cm 2 . A subsequent vacuum annealing (from 400°C to 800°C) weakens the int…
Conductivity and structure of a liquid-crystalline organic conductor
We have measured the dc conductivity and lattice parameters of hexa(hexylthio)triphenylene (HHTT) saturation doped by exposure to iodine vapor, using a four-probe resistivity technique and powder x-ray diffraction. The compound was further characterized by differential scanning calorimetry, thermogravimetric analysis,…
Porphyrins with exocyclic rings. 2. Synthesis of geochemically significant tetrahydrobenzoporphyrins from 4,5,6,7-tetrahydro-2H-isoindoles
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPorphyrins with exocyclic rings. 2. Synthesis of geochemically significant tetrahydrobenzoporphyrins from 4,5,6,7-tetrahydro-2H-isoindolesDonald A. May Jr. and Timothy D. LashCite this: J. Org. Chem. 1992, 57, 18, 4820–4828Publication Date (Print):August 1, 1992Publication H…
Phosphorylation site of NtrC, a protein phosphatase whose covalent intermediate activates transcription
The NtrC transcription factor is a member of a family of homologous prokaryotic regulatory proteins that participate in the transduction of extracellular and nutritional signals. It has been demonstrated that the phosphate group from a histidine residue of the phosphorylated NtrB protein autokinase is transferred to t…
Crystal structure of rhodesite, HK1-xNax+2yCa2-y{lB,3,22 ∞}[Si8O19]·(6-z)H2O, from three localities and its relation to other silicates with dreier double layers
Article Crystal structure of rhodesite, HK1-xNax+2yCa2-y{lB,3,22∞}[Si8O19]·(6-z)H2O, from three localities and its relation to other silicates with dreier double layers was published on August 1, 1992 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 199, issue 1-4).
NCS and DIN notations for the OSA‐UCS atlas samples
Abstract NCS (C/1931) and DIN (C/1931 and D65/1964) notations of the 558 OSA‐UCS atlas samples are presented in two tables. One table provides the NCS and DIN notations for the 424 regular samples; the other for the 134 near‐neutral (half‐step) samples.
Preparation of dibenzofuran‐type amorphous polyetherketone by novel etherification reaction
Abstract 4‐Fluorobenzophenone reacted with potassium carbonate in the presence of silica catalyst in diphenyl sulfone solvent to yield 4,4′‐dibenzoyldiphenyl ether. This new etherification reaction was extended to three difluoro aromatic ketones. 4,4′‐Bis(4‐fluorobenzoyl)diphenyl ether ( I ) reacted with potassium car…
Dynamic Effects in CO Adsorption on Ru/ZSM-5. Part I: Oxidative Disruption of Ru
In situ diffuse reflectance infrared spectroscopy of CO adsorption on reduced Ru/ZSM-5 reveals that, under appropriate conditions, in addition to the linearly adsorbed CO on metallic Ru particles (at 2045 ± 10 cm −1 ), two multicarbonyls involving oxidized Ru can be generated. These multicarbonyl species are character…
The effects of the electric field associated with a laser-induced pulsed discharge on the ablation-generated plumes of YBa2Cu3O7−X
The effects of a pulsed discharge on the luminous plume generated during the excimer laser ablation of YBa2Cu3O7−X are investigated in an oxygen environment. A high-voltage capacitor discharge circuit is used to generate a pulsed discharge. The pulsed discharge is initiated by the laser-induced plume. The electric fie…
Mussaendosides M and N, New Saponins from Mussaenda pubescens
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMussaendosides M and N, New Saponins from Mussaenda pubescensJun-Ping Xu, Ren-Sheng Xu, Zi Luo, Jie-Ying Dong, and He-Ming HuCite this: J. Nat. Prod. 1992, 55, 8, 1124–1128Publication Date (Print):August 1, 1992Publication History Published online1 July 2004Published inissue…
Nuclear and Particle Physics.
Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation W. S. C. Williams, Douglas S. Fielder; Nuclear and Particle Physics.. Am. J. Phys. 1 August 1992;…
2,2-Dichloro[1.1.1]propellane.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT2,2-Dichloro[1.1.1]propellane.Steven J. Hamrock and Josef MichlCite this: J. Org. Chem. 1992, 57, 18, 5027–5031Publication Date (Print):August 1, 1992Publication History Published online1 May 2002Published inissue 1 August 1992https://pubs.acs.org/doi/10.1021/jo00044a048http…
Crystal structure, H positions, and the Se lone pair of synthetic chalcomenite, Cu(H 2 O) 2 [SeO 3 ]
The compound is orthorhombic, P2 1 2 1 2 1 , with a=6.674, b=9.161, c=7.398, Z=4. Its structure has been refined to an unwheighted residual of 0.019, using all 459 observed reflections. The overall structure can be described as cross-linked chains of Cu and Se coordination polyhedra. Linked by O2 and O3, SeO 3 alterna…
Tensile properties of PVC at elevated temperatures
A series of PVC (polyvinyl chloride) compounds containing 0–100 phr (parts by weight per hundred parts of PVC resin) di-isooctyl phthalate was subjected to tensile testing at temperatures in the range from room temperature to 180°C. It was found that the relationships between elongation at break and stress at break fo…
Focusing grating coupler in AlGaAs optical waveguide
A focusing grating coupler (FGC) for focusing a guided wave into a spot in free space was fabricated in a III-V semiconductor waveguide for the first time. A FGC of 0.83-mm focal length and 0.5-mm*0.5-mm aperture for an AlGaAs waveguide and 0.83- mu m wavelength was designed and fabricated by electron-beam writing and…
Effect of Surface Pretilt Angle on Optical Properties of Surface-Stabilized Ferroelectric Liquid Crystals
Surface-stabilized ferroelectric liquid crystals (SSFLC) used with high-pretilt aligning film rubbed in a parallel direction showed three states, C1U, C1T and C2, which exhibited different optical properties. The temperature dependence of the memory angles of these states was measured for eight kinds of SSFLC sample c…
Calculation of phase equilibria for AISI M2 high‐speed steel
Thermo‐calc computations have been made for the iron‐rich corner of the system Fe‐Cr‐Mo‐W‐V‐C to obtain phase equilibria for AISI M2 high‐speed steel (German designation S‐6‐5‐2). The calculations describe the main transformation temperatures of this steel with good accuracy. The phases which are present during austen…
Mixed-valence lanthanum titanium (III/IV) oxosilicate La4Ti9Si4O30. A novel perrierite-related compound, La4Ti(Si2O7)2(TiO2)4m (m = 2), with a quasi-two-dimensional rutile-based structure
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMixed-valence lanthanum titanium (III/IV) oxosilicate La4Ti9Si4O30. A novel perrierite-related compound, La4Ti(Si2O7)2(TiO2)4m (m = 2), with a quasi-two-dimensional rutile-based structureShumin Wang and Shiou Jyh HwuCite this: J. Am. Chem. Soc. 1992, 114, 17, 6920–6922Public…
Evaluation of Mott's parameters in BF¯ doped polypyrrole films
The temperature dependence of the d.c. conductivity of electrochemically polymerized polypyrrole films having different percentage of BF¯ ions has been investigated in the temperature range 77–300 K. It is found that reasonable values of Mott's parameters are obtained for films having low doping level.