Results 221 to 230 of about 506,757 (254)

Temperature dependencies and apparent activation energies of stomatal opening and closing

Planta, 1970
Stomatal opening movements in response to illumination, and stomatal closure following darkening were studied in leaf sections of Zea mays, using air-flow porometers. Stomatal opening is characterized by a phase of linear increase of air flow through the leaf (slope = "opening velocity"); stomatal closure follows a relaxation curve from which a time ...
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Apparent Activation Energy of the Curing of Epoxy Resin by DTA

The Journal of the Society of Chemical Industry, Japan, 1969
示差熱分析(DTA)によって,グリシジルエーテル型エポキシ樹脂に典型的な硬化剤であるエチレンジアミン(EDA),ジメチルオクチルアミン(DMOA),ヘキサヒドロフタル酸無水物(HHPA),BF3-n-ヘキシルアミン(BF3-nHA)を用いて,その硬化を研究した。DTAの動力学の解析はKissingerの方法とBorchardtの方法によって行なった。Kissinger法によって得られた見かけの活性化エネルギー(E)はEDA,DMOA,BF3-nHA,HHPAに対してそれぞれ13.2,12.7,26.0,13.6kcal/molであった。Borchardt法による昇温速度5℃/minのときのEはそれぞれEDA,DMOA,BF3-nHA,HHPAに対し27.7,14.3,25.5,47.7kcal ...
Takashi KAMON, Kazumi SAITO, Yasuhiko MIWA, Kensaku SAEKI   +3 more
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Apparent activation energies and apparent frequency factor in polarographic waves of paludrine-Zn(II)

Electrochimica Acta, 1993
Abstract Arrhenius and Vlcek plots of ac 1 and dp polarograms of paludrine-Zn complexes are tested in order to understand the apparent activation energies and pre-exponential factor, and their dependence on the potential. These empirical treatments are useful for obtaining information about the energetic contributions of the elemental processes ...
F. Vicente, A. Roig, C. Sanz, J. López
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Apparent Activation Energy of Chemical Reactions at High Temperature

The Physics of Fluids, 1969
According to the usual form of measured cross sections, the slope of an Arrhenius plot differs from the activation energy by an electron volt or so at high T. Thus, cross-section shape is needed before activation energy can properly be deduced from rate data.
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Apparent Rate Constants and Activation Energies for the Photochemical Decomposition of Various Olefins

Journal of the Air Pollution Control Association, 1965
The photochemical reaction of various olefins and nitrogen dioxide was studied under conditions of controlled temperature, pressure, and humidity in a 200 liter stirred glass reactor. The hydrocarbon concentration in the reactor during four and five hour irradiation periods was monitored with a flame ionization chromatograph.
F C, ALLEY, G B, MARTIN, W H, PONDER
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Apparent Activation Energies for Molecular Motions in Solid Asphalt

Energy & Fuels, 2006
The hydrogen spin−lattice relaxation time in the rotating frame was measured for three whole asphalts at temperatures ranging from 20 to −45 °C. These data were used to calculate the apparent activation energies for the molecular motion of the aromatic and aliphatic components found in asphalt. The measured activation energies ranged from 8.8 to 9.8 kJ/
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Apparent Activation Energies of the Non-isothermal Degradation of Eva Copolymer

Journal of Thermal Analysis and Calorimetry, 1999
When ethylene-vinyl acetate copolymer, EVA, is heated, a two-stage thermal degradation occurs following its melting. The vinyl acetate content of the copolymer was determined to be 43.8% by using TA 2950 and TA 2050 thermogravimetric instruments. TG/FTIR was used to detect the evolved gas.
X. E. Cai, H. Shen
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Apparent activation energy of hydrolysis of some cellulosic materials

Journal of Polymer Science, 1960
AbstractApparent activation energies for heterogeneous acid hydrolysis of four samples of cellulose which differed in crystallinity were calculated separately for the amorphous and crystalline regions, from data obtained under drastic hydrolytic conditions.
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On the apparent activation energy for trapped electron decay in alkaline glasses

International Journal for Radiation Physics and Chemistry, 1974
Abstract In the temperature range 113–173 K the apparent activation energy for thermal decay of trapped electrons in 8 mol dm −3 NaOH glass is zero. Upon photobleaching one observes either positive or negative values of the activation energy depending on the temperature of irradiation.
J. Kroh, A. Płonka
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Determining the “apparent” activation energy of concrete

Cement and Concrete Research, 2002
L. D'Aloia, G. Chanvillard
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