MNDO effective charge model study of conformations of zwitterionic and neutral forms of glycine, alanine and serine in the gas phase and in solution

1990 ◽  
Vol 207 (1-2) ◽  
pp. 103-114 ◽  
Author(s):  
Osamu Kikuchi ◽  
Toru Natsui ◽  
Teruya Kozaki
Keyword(s):  
Gas Phase ◽  
Effective Charge ◽  
Model Study ◽  
Charge Model

Cold-Model Study on Fluidized-Bed Photo-Oxidation Reactor for Shenfu Coal

2011 ◽  
Vol 201-203 ◽  
pp. 2741-2744
Author(s):  
Ya Ting Zhang ◽  
Guang Heng Wang ◽  
Wei Zhao ◽  
An Ning Zhou
Keyword(s):  
Particle Size ◽  
Gas Phase ◽  
Fluidized Bed ◽  
Fluidized Bed Reactor ◽  
Pipe Diameter ◽  
Flow State ◽  
Cold Model ◽  
Photo Oxidation ◽  
Model Study ◽  
Oxidation Reactor

The flow state of both the solid and gas phase in the fluidized-bed photo-oxidation reactor for Shenfu coal was studied by cold-model tests. The results showed that the appropriate pipe diameter, particle size of coal, and the coal addition for the gas-solid fluidized-bed reactor were 22 mm, 60-80 mesh, and 10g, respectively.

scholarly journals NAT-rock formation by mother clouds: a microphysical model study

2002 ◽  
Vol 2 (2) ◽  
pp. 93-98 ◽  
Author(s):  
S. Fueglistaler ◽  
B.P. Luo ◽  
C. Voigt ◽  
K.S. Carslaw ◽  
Th. Peter
Keyword(s):  
Particle Size ◽  
Nitric Acid ◽  
Particle Size Distribution ◽  
Gas Phase ◽  
Cloud Base ◽  
Number Density ◽  
Monodisperse Particle ◽  
Model Study ◽  
Rock Mechanism ◽  
Stratospheric Clouds

Abstract. Polar stratospheric clouds (PSCs) of type 1a or 1a-enh containing high number densities of nitric acid trihydrate (NAT) particles, can act as mother clouds for extremely large NAT particles, termed NAT-rocks, provided the air below the clouds is supersaturated with respect to NAT. Individual NAT particles at the cloud base fall into undepleted gas phase and rapidly accelerate due to a positive feedback between their growth and sedimentation. The resulting reduction in number density is further enhanced by the strong HNO3 depletion within a thin layer below the mother cloud, which delays subsequent particles. This paper introduces the basic microphysical principles behind this mother cloud/NAT-rock mechanism, which produces 10-4 cm-3 NAT-rocks with radii around 10 mm some kilometers below the mother cloud. The mechanism does not require selective nucleation and works even for a monodisperse particle size distribution in the mother cloud.

Methane gas-phase dynamics in marine sediments: A model study

2009 ◽  
Vol 309 (3) ◽  
pp. 189-220 ◽  
Author(s):  
J. M. Mogollon ◽  
I. L'Heureux ◽  
A. W. Dale ◽  
P. Regnier
Keyword(s):  
Gas Phase ◽  
Marine Sediments ◽  
Phase Dynamics ◽  
Methane Gas ◽  
Model Study

scholarly journals Importance of the surface reaction OH+Cl<sup>-</sup> on sea salt aerosol for the chemistry of the marine boundary layer – a model study

2006 ◽  
Vol 6 (3) ◽  
pp. 3657-3685 ◽  
Author(s):  
R. von Glasow
Keyword(s):  
Boundary Layer ◽  
Gas Phase ◽  
Marine Boundary Layer ◽  
Sulfur Cycle ◽  
Sea Salt ◽  
Sea Salt Aerosol ◽  
Sulfate Production ◽  
Model Study ◽  
Additional Production ◽  
A Minor

Abstract. The reaction of the hydroxyl radical with chloride on the surface of sea salt aerosol producing gas phase Cl2 and particulate OH- and its implications for the chemistry of the marine boundary layer under coastal, remote, and very remote conditions have been investigated with a numerical model. This reaction had been suggested by Laskin et al. (2003) to play a major role in the sulfur cycle in the marine boundary layer by increasing the sulfate production in sea salt by O3 oxidation due to the additional production of alkalinity in the particle. Based on literature data a new &amp;quotbest estimate'' for the rate coefficient of the reaction was deduced and applied, showing that the additional initial sulfate production by this reaction is less than 1%, therefore having only a minor impact on sulfate production. Even though the gas phase concentration of Cl2 increased strongly in the model the concentration of Cl radicals increased by less than 5% for the &amp;quotbest guess'' case. Additional feedbacks between the cycles of chlorine and sulfur in the marine boundary layer are discussed as well as a two-stage acidification of large fresh sea salt aerosol.

Sign in / Sign up

Export Citation Format

Share Document