Results 211 to 220 of about 1,083,914 (265)

Reply to “‘Phantom Activation Volumes' Are Indeed Real Activation Volumes”

The Journal of Physical Chemistry A, 2002
In the preceding article,1 Weber and van Eldik (W&E) criticized our paper2 “Phantom Activation Volumes” (PAV). We had reported four examples of increase in rate with rising viscosity of thermal pericyclic reactions: an intermolecular Diels-Alder (DA),3 an intramolecular DA,3,4 a 1,3-dipolar cycloaddition (1,3-DC),3 and a Claisen rearrangement.4,5 In ...
Raymond A. Firestone, Kevin A. Swiss
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Molecular dynamics calculation of molecular volumes and volumes of activation

Physical Chemistry Chemical Physics, 2012
Experimentally, the effects of pressure on reaction rates are described by their pressure derivatives, known as volumes of activation. Transition state theory directly links activation volumes to partial molar volumes of reactants and transition states.
J, Spooner, H, Wiebe, N, Boon, E, Deglint, E, Edwards, B, Yanciw, B, Patton, L, Thiele, P, Dance, N, Weinberg   +9 more
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Topological Active Volumes

2003
In the last years, deformable models raised much interest and found various applications in the field of 2D and 3D computer vision. Active surfaces are usually employed for segmentation and object reconstruction. In this paper, a new model for 3D image segmentation is proposed, the Topological Active Volumes (TAV).
Noelia Barreira, Manuel G. Penedo, Cástor Mariño, F. M. Ansia   +3 more
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Active volume sound absorber

The Journal of the Acoustical Society of America, 1999
The absorbtion cross section (ACS) of a passive volume sound absorber asymptotically equals its geometric cross section. On the other hand, the ACS of an active absorber principally could be arbitrarily large. However, the increase of the ACS results in a rapid growth of the near acoustic fields.
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Solvent effect on the volume of activation and volume of the Diels–Alder reaction

Journal of Physical Organic Chemistry, 2001
AbstractVolumes of activation, ΔV≠, and reaction, ΔV, partial molar volumes, $\bar{V}$, and enthalpies of solution, ­ΔsolH, were determined for tetracyanoethylene, cyclopentadiene, 1,3‐butadiene, trans, trans‐1,4‐diphenyl‐1,3‐butadiene and their Diels–Alder adducts at 25 °C in some solvents of π‐ and n‐donor type.
Kiselev V., Konovalov A., Asano T., Kashaeva E., Iskhakova G., Shihab M., Medvedeva M.   +6 more
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Hydrothermal activity and the volume of the oceans

Deep Sea Research Part II: Topical Studies in Oceanography, 1994
Abstract The volume of the world ocean can be regulated by exchange processes between the crust and the mantle. Hydrothermal systems of fast-spreading mid-ocean ridges operate at the critical pressure of seawater, which ensures optimal heat transport and maximal penetration of hydrothermal fluids.
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The active fiber in a volume conductor

IEEE Transactions on Biomedical Engineering, 1974
This paper considers the quantitative description of intracellular and extracellular fields of a single circular cylindrical fiber resulting from the propagation of an action potential (AP). Several formulations are noted, but one, which permits identification of free-space source-sink relationships, is examined in some detail; the physical models ...
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Activation Volume of DNA Duplex Formation

Biochemistry, 1997
The denaturation-renaturation thermal hysteresis was used to investigate the kinetics of the helix-coil equilibrium of four 22-base pair homopurine-homopyrimidine duplex oligonucleotides with fractional G x C base pair content (f(G x C)) between 0.14 and 0.5.
M C, Lin, R B, Macgregor
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Activation Volume for Creep in the Upper Mantle

Science, 1979
The activation volume for creep, V * of olivine-rich rocks has been determined in pressure-differential creep experiments on dunite at temperatures from 1100° to 1350°C and confining pressures from 5 to 15 kilobars. Values of V * range from 10.6 to 15.4 cubic centimeters per mole with a mean ...
J V, Ross, H G, Ave'lallemant, N L, Carter   +2 more
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A structured perspective of volumes on active learning

Neurocomputing, 2020
Abstract We approximate the version space which covers all feasible classification hypotheses into a structured geometric hypersphere against agnostic distribution. We present a structured perspective that divides the available active learning (AL) sampling approaches into two kinds of strategies: Outer Volume Sampling and Inner Volume Sampling.
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