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1.
Nonaethylene glycol and pentadecaethylene glycol and their dimethyl ethers have been prepared and characterized, with respect to crystallinity by wide- and small-angle X-ray scattering, Raman scattering, i.r. spectroscopy and differential scanning calorimetry. Wide-angle X-ray scattering is similar to that from high molecular weight poly(ethylene oxide). The crystal habit is lamella. The lamellae are highly crystalline and the surface layers are ordered. Comparison with crystalline poly(ethylene oxide) prepared conventionally, and having a distribution of chain lengths, shows that such samples crystallize into lamellae with disordered surface layers. 相似文献
2.
Martin Proudmore Ji-Feng Ding Richard H. Mobbs Stephen G. Yeates Colin Price Colin Booth 《Journal of polymer science. Part A, Polymer chemistry》1995,33(10):1615-1625
Poly(hexafluoropropylene oxide), poly(HFPO), networks were prepared from functional polymers by end linking via urethane groups. The prepolymers were characterized by NMR spectroscopy and GPC. The networks were characterized by determination of the number of network chains from the shear modulus, and were snown to contain both trifunctional crosslinks and difunctional links. The properties of the networks were investigated by a range of techniques. Compared with fully-fluorinated networks formed via triazine cross-links, investigated previously, the urethane-linked networks were more readily prepared but were poorer elastomers, were less thermally stable, and were less resistant to swelling by common polar solvents. © 1995 John Wiley & Sons, Inc. 相似文献
3.
Nucleophilic attack by various polyfluoro- and perfluoro-phenoxides upon decafluorobiphenyl, perfluoro-4-methylbiphenyl and perfluoro-4,4′-dimethylbiphenyl in dimethylacetamide solution gave a number of high boiling aryl ethers by mono- and di-substitution. The disodium salt of octafluoro-4-4′-dihydroxybiphenyl with octafluoroanisole in dimethylacetamide gave another aryl ether containing four rings, but the dipotassium salt of hexafluoro-3,3′-dihydroxy-4,4t?-bis(trifluoromethyl)biphenyl (prepared by the action of potassium hydroxide upon perfluoro-4,4′-dimethylbiphenyl) with octafluorotoluene gave a complex mixture of products. The syntheses of various new compounds used as intermediates are described. 相似文献
4.
Karen A. Barnes Richard J. Fussell James R. Startin Hilary J. Mobbs Richard James Stewart L. Reynolds 《Rapid communications in mass spectrometry : RCM》1997,11(2):159-164
A rapid method, using high-performance liquid chromatography (HPLC)/atmospheric pressure chemical ionization-mass spectrometry, has been developed for the determination of fenbutatin oxide in tomatoes, cucumbers and bananas. Samples were homogenized with sodium carbonate and ethyl acetate, filtered through sodium sulphate, concentrated and solvent exchanged into acetonitrile prior to analysis. HPLC was performed on a Hypercarb column with 10:90 acetic acid (5% v/v glacial acetic acid in water)/acetonitrile at a flow rate of 1 mL/min. Positive ionization selected-ion monitoring was performed on the 7 isotopic cluster ions from the tris(2-methyl-2-phenylpropyl) tin fragment. A comparison of solvent-based and extract-based standards showed that tomato and cucumber matrices had a slight enhancement effect on the signal intensity, whereas the banana matrix exerted a signal suppression effect. Calibration was linear over the range 0.25–5.0 ng/μL. The mean spike recoveries (extracts spiked at 0.5 mg/kg) were 88% for tomatoes and 80% for both cucumbers and bananas with relative standard deviations of 6%, 7% and 8% respectively. Limits of detection were commodity dependent and ranged from 0.06–0.12 ng/μL (equivalent to 0.01–0.02 mg/kg in the crop). Ionization was stable for long analytical time periods. © 1997 Crown Copyright 相似文献
5.
Amigo CF Collado IG Hanson JR Hernández-Galán R Hitchcock PB Macías-Sánchez AJ Mobbs DJ 《The Journal of organic chemistry》2001,66(12):4327-4332
The sesquiterpenoid panasinsane derivatives 11 and 14-16 have been prepared from caryophyllene oxide (7). The novel rearrangement reactions of compounds 11 and 14 under TCNE-catalyzed solvolysis conditions and the reactions of compounds 15 and 16 under superacid conditions (HSO3F/Et2O, -63 degrees C) have been investigated. The ginsenol derivative 17 is obtained from compounds 11 and 14 under TCNE-catalyzed conditions. The rearrangement of compounds 15 and 16 under superacid conditions leads to the novel sesquiterpene derivatives (1S,4S,7S,10S,11S)-3,3,10,11-tetramethyltricyclo[5.3.1.0(4,10)]undecan-1,11-yl sulfate (19) and (1S,4S,5S,8S)-2,2,4,8-tetramethyl tricyclo[3.3.2.1(4,8)]undecan-11-one (20). The influence of the secondary hydroxyl group at C-5 of the panasinsane derivatives on the course of these rearrangements is discussed. 相似文献
6.
A host-guest optical sensor for the determination of aliphatic amines as exemplified by octylamine is proposed. It is based on the reversible fluorescence enhancement of heptakis(2,6-di-O-isobutyl)-β-cyclodextrin(DOB-β-CD) hosting tetraphenylporphyrin (TPP) immobilized in poly(vinyl chloride) (PVC) membrane by aliphatic amine extracted from aqueous phase into membrane phase. The optimum membrane contained 1.15 wt % TPP, 6.15 wt % DOB-β-CD as sensing reagent and other membrane materials. The fluorescence enhancement of the membrane resulted from the formation of a stable three-component complex among DOB-β-CD, TPP, and aliphatic amines. With the optimum conditions described, the fluorescence response of the sensor to octylamine shows a good correlation with the theoretically derived equation in the range 1.0 × 10–6 to 8.0 × 10–4 mol/L. The response characteristics including reversibility, response time, reproducibility and lifetime and selectivity of this optical device are also discussed in detail. This sensor has also been applied for the determination of octylamine in water samples containing interferents with satisfactory recovery. 相似文献
7.
S. Bashir R. W. McCabe C. Boxall M. S. Leaver D. Mobbs 《Journal of nanoparticle research》2009,11(3):701-706
Forced hydrolysis of Fe(III) ions in acidic media was performed under controlled synthetic conditions to produce α- and β-FeOOH
iron oxides. The forced hydrolysis synthesis was carried out, separately, in an aqueous medium and the lamellar lyotropic
liquid crystalline phase of a commercial non-ionic surfactant/water system. The FT-IR analyses confirmed formation of α- and
β-FeOOH iron oxides in the aqueous and the surfactant media with slight formation of ferrihydrite and haematite. TEM micrographs
have shown that particles formed in the lamellar lyotropic phase are smaller than those produced in the aqueous medium with
their smallest size dimension being constrained in the nanometre scale with a size ranging between 5 and 100 nm. Particles
produced in the nanoscale size appeared to have different optical properties compared to their counterparts produced in the
microscale size. 相似文献
8.
Amita Gupta Alexei Yu Ganin Parmanand Sharma Vikrant Agnihotri LM Belova KV Rao Mikhail E Kozlov AA Zakhidov RH Baughman 《Pramana》2002,58(5-6):1051-1059
We present studies of novel nanocomposites of BiNi impregnated into the structure of opals as well as inverse opals. Atomic force microscopy and high resolution elemental analyses show
a highly ordered structure and uniform distribution of the BiNi filler in the matrix. These BiNi-based nanocomposites are
found to exhibit distinct ferromagnetic-like ordering with transition temperature of about 675 K. As far as we know there
exists no report in literature on any BiNi compound which is magnetic. 相似文献
9.
A new turbulence model for the flow of a two phase (liquid-liquid) flow in an inclined pipe is presented. An eddy viscosity is used to model the effects of shear induced turbulence and bubble induced turbulence. The cross-pipe momentum transport arising from the buoyant rise of bubbles across the axial flow is also modelled. Numerical simulations have been carried out in both one and two dimensions. One and two dimensional numerical simulations are presented.On leave from the University of Leeds, Leeds LS2 9JT, U.K. 相似文献
10.
Hideo Makimura Tooru M Mizuno Jason W Mastaitis Reuven Agami Charles V Mobbs 《BMC neuroscience》2002,3(1):18-6