Compact and diffuse double layer interaction in unsupported system small-signal response

Previous exact results for the small-signal impedance of an unsupported electrode/material/electrode system which include effects of the finite size of charge carriers are simplified and discussed. The material contains non-recombining charges of opposite sign with the positive one immobile and uniformly distributed. General boundary conditions which encompass the range from no electrode reaction to ohmic electrode behavior are employed. In the presence of an electrode reaction, the interaction of the compact and diffuse double layers leads to considerably more complexity in the equivalent circuit than might appear in simple treatments of the supported case, in which the diffuse double layer capacitance is neglected or the compact double layer and diffuse double layer capacitances are placed in series. Two different approximate equivalent circuits made up of frequency-independent elements are found which yield remarkable agreement with the exact results over the entire frequency range of interest. The first involves the ordinary approximate circuit (OAC) previously found in the absence of compact layer effects plus a series compact layer contribution involving a parallel resonant circuit with quality factor at resonance which may approach unity. Pseudo-inductance effects are found to be extremely significant in this representation. The second approximate equivalent circuit, simpler and almost as accurate as the first, has the same form as the original OAC but with its reaction element values altered by the presence of the compact layer. For non-Butler-Volmer electrode kinetics an upper limit is found for the experimentally determinable apparent reaction rate constant, a feature of practical importance for thin films or membranes. The response of thin films and membranes, including compact layer effects, can very readily be erroneously confused with pure bulk response, yielding entirely incorrect values for the geometrical capacitance and bulk resistance of the material.     

Pionic Kα X-ray energy and linewidth IN 20Ne and 22Ne

We have measured the energies and linewidths of the pionic K_α X-rays for ²⁰Ne and ²²Ne using a natural liquid-neon target. The results are

     

93.

Searches for muon-electron and muon-positron conversion in titanium     

Ahmad S  Azuelos G  Blecher M  Bryman D  Burnham RA  Clifford ET  Depommier P  Dixit MS  Gotow K  Hargrove CK  Hasinoff M  Macdonald JA  Mes H  Numao T  Poutissou J  Poutissou R  Spuller J  Summhammer J 《Physical review letters》1987,59(9):970-973

     

94.

The influence of substituted alcohols on the temperature of maximum density of water     

Digby D. Macdonald  B. Dolan  J. B. Hyne 《Journal of solution chemistry》1976,5(6):405-416

The influence of various substituted (including halogenated) alcohols on the temperature of maximum density (TMD) of water has been investigated. Evaluation of the structural contribution to the shift in the TMD demonstrates that trifluoroethanol, hexafluoroisopropanol, and neopentyl alcohol are structure makers, whereas trichloroethanol and tribromoethanol are structure breakers. The results are discussed in terms of an excluded volume model.     

95.

Condensation polymers from 1,2,5-thiadiazole-3,4-dicarboxylic acid     

Robert N. Macdonald  W. H. Sharkey 《Journal of polymer science. Part A, Polymer chemistry》1973,11(10):2519-2536

A series of polyamides was prepared by interfacial polymerization of diamines with 1,2,5-thiadiazole-3,4-dicarbonyl chloride. Polyamides from secondary cycloaliphatic diamines and aromatic diamines have high softening points, high glass transition temperatures, and good thermal stability. Secondary amines, in particular cycloaliphatic secondary amines, form very high molecular weight polyamides. The polyamide from trans-2,5-dimethylpiperazine and 1,2,5-thiadiazole-3,4-dicarbonyl chloride is soluble in chloroform and 1,1,2-trichloroethane and has been cast into films and spun into fibers from those solvents. Fibers of this polymer are strong and have very high work recovery from small strains. In addition, these fibers show good retention of strength and work recovery over a range of temperatures and humidities.     

96.

The influence of cyclic alcohols on the temperature of maximum density of water     

Digby D. Macdonald  Alice Maclean  James B. Hyne 《Journal of solution chemistry》1979,8(2):97-103

The effect of a homologous series of cyclic monohydric alcohols (C₄−C₈) on the temperature of maximum density of water has been examined. The structural contribution to the shift in the temperature of maximum density (TMD) is positive (increased structuredness) for alcohols up to C₆ but becomes negative at C₈. The behavior is compared with that of linear monohydric alcohols and Ω-diols.     

97.

Flow-injection methods for the determination of uracil derivatives with voltammetric detection     

B. Bouzid  A.M.G. Macdonald 《Analytica chimica acta》1988

Flow-injection methods are described for the determination of 18 uracil derivatives and related compounds, by means of differential-pulse amperometry (d.p.a.) or differential-pulse cathodic stripping voltammetry (d.p.c.s.v.). The carrier stream is a borax/KNO₃/HNO₃ (of NaOH) solution containing 0.001% (v/v) Triton X-100. This surfactant displaces the oxygen reduction peak to such negative potentials that deaeration is unnecessary for detection of compounds having peak potentials in the range 180–70 mV (vs. Ag/AgCI) at pH 7.6. At the hanging mercury drop electrode, the uracil derivative is deposited from the flowing sample at a fixed potential more positive than the relevant peak potential and stripped under stopped-flow or slow-flow conditions. In the amperometric mode, a constant potential also more positive than the relevant peak potential is applied to the dropping mercury electrode and the resulting peak is measured under flow conditions. Linear calibration graphs were found for most of the compounds at 10^?6–10^?7 M by d.p.a, and about one order of magnitude lower by d.p.c.s.v.. The limit of determination for 5-iodouracil was 5×10^?9 M (ca. 1.2 ng ml^?1). Separation is needed for applications to blood or urine. Simple deproteination followed by high-performance liquid chromatography with a reversed-phase column proved satisfactory. Separations of various uracil derivatives, and of 5-fluorouracil, uric acid and 5-fluorodeoxyuridine, are described; spectrophotometric and amperometric detectors were used sequentially to check performance.     

98.

Asymmetrische Epoxidierung von Chalkonen mit chiral modifizierten Lithium- und Magnesium-tert-butylperoxiden     

Catherine L. Elston  Richard F. W. Jackson  Simon J. F. Macdonald  P. J. Murray 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》1997,109(4):379-381

     

99.

Energy partitioning and reaction dynamics in the chemiluminescent channel of the reaction: HS + O3 → HSO* + O2     

D.J.W. Kendall  J.J.A. O&#x;Brien  J.J. Sloan  R.Glen Macdonald 《Chemical physics letters》1984,110(2):183-190

The title reaction forms electronically excited HSO(òA′) directly, with considerable vibrational and rotational excitation as well. The internal excitation of the HSO fragment is the maximum possible consistent with the concurrent formation of an O₂(¹Δ_g) molecule as the other reaction product. The observed vibrational excitation peaks in the υ′= 2 level of the υ₃ mode. No evidence about possible excitation of the other vibrational modes of HSO could be obtained.     

100.

A Note on “Modified Chain Displacement Function of Gaussian Networks” by A. H. Crossland     

L F. Macdonald  T. W. Chan 《高分子科学杂志，A辑:纯化学与应用化学》2013,50(2):559-562

Crossland claims that the development of the conventional Gaussian theory of rubber elasticity does not take into account the requirement that the polymer chain end-to-end vector must be equal in direction to the network junction-to-junction vector. Reintroducing the directional probability, he develops a novel Gaussian strain-energy function. H correct, Crossland's work is a significant contribution, resulting in notable improvements in important models in rubber elasticity and polymer rheology. Unfortunately, there is an error in Crossland's analysis. Correction of the error reduces Crossland's results to those of the conventional Gaussian theory and shows that the conventional theory does correctly account for the directional probability. The “improved” strain-energy function, therefore, has no theoretical basis and, at best, must be considered purely empirical.     

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20Ne	22Ne
Neenergy (keV)	239.12±0.14	230.49±0.88
width (keV)	15.43±0.41	12.65±3.51

The influence of substituted alcohols on the temperature of maximum density of water

The influence of various substituted (including halogenated) alcohols on the temperature of maximum density (TMD) of water has been investigated. Evaluation of the structural contribution to the shift in the TMD demonstrates that trifluoroethanol, hexafluoroisopropanol, and neopentyl alcohol are structure makers, whereas trichloroethanol and tribromoethanol are structure breakers. The results are discussed in terms of an excluded volume model.     

Condensation polymers from 1,2,5-thiadiazole-3,4-dicarboxylic acid

A series of polyamides was prepared by interfacial polymerization of diamines with 1,2,5-thiadiazole-3,4-dicarbonyl chloride. Polyamides from secondary cycloaliphatic diamines and aromatic diamines have high softening points, high glass transition temperatures, and good thermal stability. Secondary amines, in particular cycloaliphatic secondary amines, form very high molecular weight polyamides. The polyamide from trans-2,5-dimethylpiperazine and 1,2,5-thiadiazole-3,4-dicarbonyl chloride is soluble in chloroform and 1,1,2-trichloroethane and has been cast into films and spun into fibers from those solvents. Fibers of this polymer are strong and have very high work recovery from small strains. In addition, these fibers show good retention of strength and work recovery over a range of temperatures and humidities.     

The influence of cyclic alcohols on the temperature of maximum density of water

The effect of a homologous series of cyclic monohydric alcohols (C₄−C₈) on the temperature of maximum density of water has been examined. The structural contribution to the shift in the temperature of maximum density (TMD) is positive (increased structuredness) for alcohols up to C₆ but becomes negative at C₈. The behavior is compared with that of linear monohydric alcohols and Ω-diols.     

Flow-injection methods for the determination of uracil derivatives with voltammetric detection

Flow-injection methods are described for the determination of 18 uracil derivatives and related compounds, by means of differential-pulse amperometry (d.p.a.) or differential-pulse cathodic stripping voltammetry (d.p.c.s.v.). The carrier stream is a borax/KNO₃/HNO₃ (of NaOH) solution containing 0.001% (v/v) Triton X-100. This surfactant displaces the oxygen reduction peak to such negative potentials that deaeration is unnecessary for detection of compounds having peak potentials in the range 180–70 mV (vs. Ag/AgCI) at pH 7.6. At the hanging mercury drop electrode, the uracil derivative is deposited from the flowing sample at a fixed potential more positive than the relevant peak potential and stripped under stopped-flow or slow-flow conditions. In the amperometric mode, a constant potential also more positive than the relevant peak potential is applied to the dropping mercury electrode and the resulting peak is measured under flow conditions. Linear calibration graphs were found for most of the compounds at 10^?6–10^?7 M by d.p.a, and about one order of magnitude lower by d.p.c.s.v.. The limit of determination for 5-iodouracil was 5×10^?9 M (ca. 1.2 ng ml^?1). Separation is needed for applications to blood or urine. Simple deproteination followed by high-performance liquid chromatography with a reversed-phase column proved satisfactory. Separations of various uracil derivatives, and of 5-fluorouracil, uric acid and 5-fluorodeoxyuridine, are described; spectrophotometric and amperometric detectors were used sequentially to check performance.     

Energy partitioning and reaction dynamics in the chemiluminescent channel of the reaction: HS + O3 → HSO* + O2

The title reaction forms electronically excited HSO(òA′) directly, with considerable vibrational and rotational excitation as well. The internal excitation of the HSO fragment is the maximum possible consistent with the concurrent formation of an O₂(¹Δ_g) molecule as the other reaction product. The observed vibrational excitation peaks in the υ′= 2 level of the υ₃ mode. No evidence about possible excitation of the other vibrational modes of HSO could be obtained.     

A Note on “Modified Chain Displacement Function of Gaussian Networks” by A. H. Crossland

Crossland claims that the development of the conventional Gaussian theory of rubber elasticity does not take into account the requirement that the polymer chain end-to-end vector must be equal in direction to the network junction-to-junction vector. Reintroducing the directional probability, he develops a novel Gaussian strain-energy function. H correct, Crossland's work is a significant contribution, resulting in notable improvements in important models in rubber elasticity and polymer rheology. Unfortunately, there is an error in Crossland's analysis. Correction of the error reduces Crossland's results to those of the conventional Gaussian theory and shows that the conventional theory does correctly account for the directional probability. The “improved” strain-energy function, therefore, has no theoretical basis and, at best, must be considered purely empirical.