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181.
Mohd Izham binSaiman Gemma L. Brett Ramchandra Tiruvalam Michael M. Forde Kate Sharples Adam Thetford Robert L. Jenkins Nikolaos Dimitratos Jose A. Lopez‐Sanchez Damien M. Murphy Donald Bethell David J. Willock Stuart H. Taylor David W. Knight Christopher J. Kiely Graham J. Hutchings 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2012,124(24):6083-6087
182.
183.
An experimental investigation explored the effects of varying reactant concentration and Reynolds number on the formation
of product in a jet of air/N2/HCl flowing into a co-issuing stream of air/NH3. Turbulent mixing resulted in the production of NH4Cl particles by a chemical reaction with negligible heat release. Laser light was elastically scattered in the transition
regime between Rayleigh and Mie scattering from the particles. Scattered light intensity served as an indicator of particle
mass concentration. Radial profiles of mean and root mean square concentrations were obtained in the self-similar far field
region of the jet. The stoichiometric mixture fraction was varied by varying the concentration of NH3 in the co-flowing stream. It was found that the “flame” length decreased with increasing stoichiometric mixture fraction,
and was independent of Reynolds number. The overall amount of product decreased as the stoichiometric mixture fraction was
increased from 0.06 to 0.27, while the amount of limiting reactant was the same in both cases.
Received: 28 April 1998/Accepted: 16 November 1999 相似文献
184.
Melt crystallized polyethylenes with different crystallization histories were irradiated with γ-rays and examined for various properties. These include solubility (gel content), melting and recrystallization behavior, load extension behavior, and creep properties. Even for the same dose, very significant differences were observed for the different sample types. Although such differences have been reported previously, the present work reveals that these differences can be unusually large and that they are displayed by a range of different tests with a consistent correlation between them. The underlying trend is that in poorly crystallized samples the radiation is much more effective in forming networks than in samples of highly developed crystallinity. This finding may merely indicate that cross-linking is more abundant in the amorphous region than in the crystallites; nevertheless, analogy with single crystals suggests that in addition details of the fold surface morphology and the nature of the lamellar contact may also have a part to play. Among other properties, the elasticity of cross-linked melt was analyzed and found to be consistent with simple rubber elasticity theory, leading to an estimate of both the number of effective cross-links and of intrinsic entanglements acting as cross-links. The most conspicuous effects were observed in the creep behavior where different sample types irradiated to the same dose could behave as viscous liquids and true rubbers according to crystallization history. The relevance of such findings for the technological irradiation of polyethylene should be self-evident, particularly as the doses involved were those commonly employed in industrial applications. 相似文献
185.
V. Tirtaatmadja K. C. Tam R. D. Jenkins D. R. Bassett 《Colloid and polymer science》1999,277(2-3):276-281
Hydrophobically modified alkali-soluble emulsion (HASE) polymer is solubilized by the addition of a base. When the pH is
increased to greater than 6.5, methacrylic acids on the polymer backbone are neutralized and the carboxylated latex polymer
goes into solution causing a large increase in the viscosity due to inter-molecular associations of the hydrophobes. The stability
of the viscosity of the polymer solution at pH in the range 9–10 was studied in the presence of a strong (NaOH) and a weak
[1-amino-1-methylpropanol (AMP)] base. No change in the viscosity or the moduli was observed for the polymer in AMP. Reduction
in the viscous and elastic properties of the polymer solution in NaOH was observed after 4 weeks. Such small changes are detectable
using the superposition of oscillation on the steady shear technique. The decrease in the viscoelastic properties is attributed
to the hydrolysis reaction of the urethane groups of the macromonomer, which resulted in a decrease in the number of hydrophobes
per polymer chain. It is recommended that a weak base be used to neutralise the HASE polymer in order to avoid the possibility
of compositional changes in the polymer after neutralisation for more than 6 weeks.
Received: 19 May 1998 Accepted in revised form: 26 October 1998 相似文献
186.
Jessica L. Reiner Andrea C. Blaine Christopher P. Higgins Carin Huset Thomas M. Jenkins Christiaan J. A. F. Kwadijk Cleston C. Lange Derek C. G. Muir William K. Reagen Courtney Rich Jeff M. Small Mark J. Strynar John W. Washington Hoon Yoo Jennifer M. Keller 《Analytical and bioanalytical chemistry》2015,407(11):2975-2983
187.
Adugna S Revunova K Djukic B Gorelsky SI Jenkins HA Lemaire MT 《Inorganic chemistry》2010,49(21):10183-10190
Herein, we describe the preparation of a 2,2'-bipyridine derivative containing a redox-active N,N'-(4,4'-dimethoxydiphenylamino) substituent (1), which readily coordinates M(hfac)(2) salts [M = Mn (2), Ni (3), Cu (4)] to generate stable, neutral, and pseudo-octahedral coordination complexes, which have been fully characterized. Cyclic voltammetry and spectroelectrochemical measurements on complexes 2-4 indicate stable one-electron oxidation processes, and the formation of persistent radical cation complexes. The neutral complexes (M = Mn or Ni) were subject to one-electron oxidation with NOPF(6) in acetonitrile, and magnetic moments of the resulting solutions were obtained using the Evans method at different temperatures. Our experimental results suggest that the first reported ferromagnetically coupled metal-triarylamminum radical cation complex is obtained when M = Mn(2+), and antiferromagnetic coupling results when M = Ni(2+). These results are supported by results from density functional theory calculations, which indicate that a π spin polarization mechanism for magnetic exchange coupling is operative in singly oxidized complexes, 2-4. 相似文献
188.
189.
Xue YJ Simmons NJ Liu J Unger SE Anderson DF Jenkins RG 《Rapid communications in mass spectrometry : RCM》2006,20(11):1776-1786
A high-performance liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed and validated for the determination of a BMS drug candidate and its acyl glucuronide (1-O-beta glucuronide) in rat plasma. A 50-microL aliquot of each plasma sample was fortified with acetonitrile containing the internal standard to precipitate proteins and extract the analytes of interest. After mixing and centrifugation, the supernatant from each sample was transferred to a 96-well plate and injected into an LC/MS/MS system. Chromatographic separation was achieved isocratically on a Phenomenex Luna C(18), 3 mm x 150 mm, 3 microm column. The mobile phase contained 0.075% formic acid in 70:30 (v/v) acetonitrile/water. Under the optimized chromatographic conditions, the BMS drug candidate and its acyl glucuronide were separated from its seven glucuronide positional isomers within 10 min. Resolution of the parent from all glucuronides and acyl glucuronide from its positional isomers was critical to avoid their interference with quantitation of parent or acyl glucuronide. Detection was by positive ion electrospray MS/MS on a Sciex API 4000. The standard curve, which ranged from 5 to 5000 ng/mL, was fitted to a 1/x(2) weighted quadratic regression model for both the BMS drug candidate and its acyl glucuronide. Whole blood and plasma stability experiments were conducted to establish the sample collection, storage, and processing conditions. The validation results demonstrated that this method was rugged and repeatable. The same methodology has also been used in mouse and human plasma for the determination of the BMS drug candidate and its acyl glucuronide. 相似文献
190.
García MD Wilson AJ Emmerson DP Jenkins PR 《Chemical communications (Cambridge, England)》2006,(24):2586-2588
The synthesis of a series of beta-carboline-based analogues of the natural product fascaplysin is presented; the compounds were produced using a novel photo-oxidation reaction of 1-benzyl-4,9-dihydro-3H-beta-carbolines as the key step. 相似文献