Licvd of Cr(C,O) Films from Cr(CO)6 at 248 NM: Gas-Phase and Surface Processes

1988 ◽  
Vol 129 ◽  
Author(s):  
R. Nowak ◽  
L. Konstantinov ◽  
P. Hess
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Laser Fluence ◽  
Film Deposition ◽  
Surface Processes ◽  
Minor Role ◽  
Relative Importance ◽  
Experimental Conditions ◽  
Krf Excimer Laser ◽  
A Minor

ABSTRACTThe influence of laser fluence and carbon monoxide partial pressure on the deposition rate of thin Cr(C,O) films was investigated. The films were deposited from Cr(CO)6 mixtures with CO and Ar using a KrF excimer laser. The observed results are discussed with respect to the relative importance of gasphase and surface processes. The results reveal that under the present experimental conditions chromium atoms produced in the gas phase play only a minor role as direct film precursors in KrF laser-induced film deposition.

scholarly journals Spectroscopic evidence of large aspherical <i>β</i>-NAT particles involved in denitrification in the December 2011 Arctic stratosphere

2016 ◽  
Vol 16 (14) ◽  
pp. 9505-9532 ◽  
Author(s):  
Wolfgang Woiwode ◽  
Michael Höpfner ◽  
Lei Bi ◽  
Michael C. Pitts ◽  
Lamont R. Poole ◽  
...  
Keyword(s):  
Gas Phase ◽  
Michelson Interferometer ◽  
Emission Spectra ◽  
Deformation Mode ◽  
Spherical Particles ◽  
Lagrangian Model ◽  
Minor Role ◽  
Aspect Ratios ◽  
A Minor

Abstract. We analyze polar stratospheric cloud (PSC) signatures in airborne MIPAS-STR (Michelson Interferometer for Passive Atmospheric Sounding – STRatospheric aircraft) observations in the spectral regions from 725 to 990 and 1150 to 1350 cm−1 under conditions suitable for the existence of nitric acid trihydrate (NAT) above northern Scandinavia on 11 December 2011. The high-resolution infrared limb emission spectra of MIPAS-STR show a characteristic “shoulder-like” signature in the spectral region around 820 cm−1, which is attributed to the ν2 symmetric deformation mode of NO3− in β-NAT. Using radiative transfer calculations involving Mie and T-Matrix methods, the spectral signatures of spherical and aspherical particles are simulated. The simulations are constrained using collocated in situ particle measurements. Simulations assuming highly aspherical spheroids with aspect ratios (AR) of 0.1 or 10.0 and a lognormal particle mode with a mode radius of 4.8 µm reproduce the observed spectra to a high degree. A smaller lognormal mode with a mode radius of 2.0 µm, which is also taken into account, plays only a minor role. Within the scenarios analyzed, the best overall agreement is found for elongated spheroids with AR  =  0.1. Simulations of spherical particles and spheroids with AR  =  0.5 and 2.0 return results very similar to each other and do not allow us to reproduce the signature around 820 cm−1. The observed “shoulder-like” signature is explained by the combination of the absorption/emission and scattering characteristics of large highly aspherical β-NAT particles. The size distribution supported by our results corresponds to ∼ 9 ppbv of gas-phase equivalent HNO3 at the flight altitude of ∼ 18.5 km. The results are compared with the size distributions derived from the in situ observations, a corresponding Chemical Lagrangian Model of the Stratosphere (CLaMS) simulation, and excess gas-phase HNO3 observed in a nitrification layer directly below the observed PSC. The presented results suggest that large highly aspherical β-NAT particles involved in denitrification of the polar stratosphere can be identified by means of passive infrared limb emission measurements.

scholarly journals Spectroscopic evidence for large aspherical β-NAT particles involved in denitrification in the December 2011 Arctic stratosphere

2016 ◽  
Author(s):  
Wolfgang Woiwode ◽  
Michael Höpfner ◽  
Lei Bi ◽  
Michael C. Pitts ◽  
Lamont R. Poole ◽  
...  
Keyword(s):  
Gas Phase ◽  
Michelson Interferometer ◽  
Emission Spectra ◽  
Deformation Mode ◽  
Spherical Particles ◽  
Lagrangian Model ◽  
Minor Role ◽  
Aspect Ratios ◽  
A Minor

Abstract. We analyse polar stratospheric cloud (PSC) signatures in airborne MIPAS-STR (Michelson Interferometer for Passive Atmospheric Sounding – STRatospheric aircraft) observations under conditions suitable for the existence of nitric acid trihydrate (NAT) above northern Scandinavia on 11 December 2011. The high resolution infrared limb emission spectra of MIPAS-STR show a characteristic "shoulder-like" signature in the spectral region around 820 cm−1, which is attributed to the ν2 deformation mode of NO3− in β-NAT. Using radiative transfer calculations involving Mie and T-Matrix methods, the spectral signatures of spherical and aspherical particles are simulated. The simulations are constrained using collocated in-situ particle measurements. Simulations assuming highly aspherical spheroids with aspect ratios (AR) of 0.1 or 10.0 and a lognormal particle mode with a mode radius of 4.8 µm reproduce the observed spectra to a high degree. A smaller lognormal mode with a mode radius of 2.0 µm, which was also taken into account, plays only a minor role. Best overall agreement is found for elongated spheroids with AR = 0.1. Simulations of spherical particles and spheroids with AR = 0.5 and 2.0 return results very similar to each other and do not allow to reproduce the signature around 820 cm−1. The observed “shoulder-like” signature is explained by the combination of the emission and scattering characteristics of large highly aspherical β-NAT particles. The size distribution supported by our results corresponds with ~9 ppbv of gas-phase equivalent HNO3 at the flight altitude of ~18.5 km. The results are compared with the size distributions derived from the in-situ observations, a corresponding Chemical Lagrangian Model of the Stratosphere (CLaMS) simulation, and excess gas-phase HNO3 observed in a nitrification layer directly below the observed PSC. The presented results suggest that large highly aspherical β-NAT particles involved in denitrification of the polar stratosphere can be identified by means of passive infrared limb emission measurements.

scholarly journals Pathways of glyceride glycerol synthesis

1974 ◽  
Vol 140 (2) ◽  
pp. 249-251 ◽  
Author(s):  
Robert Rognstad ◽  
Dallas G. Clark ◽  
Joseph Katz
Keyword(s):  
Minor Role ◽  
Dihydroxyacetone Phosphate ◽  
Glycerol Phosphate ◽  
Experimental Conditions ◽  
Liver Parenchymal ◽  
Isolated Rat Liver ◽  
Glycerol Synthesis ◽  
A Minor ◽  
Parenchymal Cells ◽  
Intracellular Glycerol

Isolated rat liver parenchymal cells were incubated for various periods with [U-14C,2-3H]glycerol and the radioisotopic yields in the major products were determined, as well as the 3H/14C ratios in glyceride glycerol and intracellular glycerol phosphate. Under the conditions used (0.1mm-glycerol+10mm-l-lactate or 10mm-glycerol as substrates), only small differences were found between these 3H/14C ratios. The results suggest a minor role for a pathway of glyceride glycerol synthesis involving reduction of acylated dihydroxyacetone phosphate, under these experimental conditions.

THE REACTION OF HYDROGEN ATOMS WITH KETENE

1964 ◽  
Vol 42 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Nick Demchuk ◽  
H. Gesser
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Surface Reaction ◽  
Flow System ◽  
Minor Amount ◽  
Phase Reaction ◽  
Hydrogen Atoms ◽  
A Chain ◽  
Fast Flow ◽  
A Minor

The gas-phase reaction of atomic hydrogen with ketene has been investigated over a temperature range of −130° to 232 °C using a low-pressure, fast-flow system. In most cases methane, carbon monoxide, and ethane were the major products, but trace amounts of glyoxal were also detected. Above −96 °C. considerable evidence exists for the occurrence of a chain reaction carried by HCO radicals. The surface reaction at −196 °C produced methane and glyoxal predominantly with only a minor amount of carbon monoxide.

Tem Study of Metal Impurity Precipitates in the Surface Regions of Silicon Wafers

1987 ◽  
Vol 104 ◽  
Author(s):  
M. Seibt ◽  
K. Graff
Keyword(s):  
Particle Growth ◽  
High Resolution Electron Microscopy ◽  
Minor Role ◽  
Specimen Preparation ◽  
Dislocation Loops ◽  
Experimental Conditions ◽  
Resolution Electron ◽  
Precipitation Behaviour ◽  
Precipitation Phenomena ◽  
A Minor

ABSTRACTThe precipitation behaviour of the transition metals Co, Ni, Cu and Pd has been studied by means of conventional and high - resolution electron microscopy. Special experimental conditions for specimen preparation were chosen, which lead to the formation of haze. These conditions were the same for all metals. Therefore, a direct comparison of the respective precipitation phenomena was possible. Co and Ni were found to precipitate as Si - rich silicide particles exhibiting various morphologies attributed to different stages of particle growth and ripening. It is shown that the generation of Si- self - interstitials (and vacancies) plays a minor role in the preci-pitate formation. On the other hand Cu and Pd precipitate as metal - rich silicide particles. They form star - like colonies consisting of small particles and extended extrinsic edge - type dislocation loops. The precipitation behaviour of these two met-als is governed by the generation of Si - self - interstitials due to the large misfit of the metal - rich silicide particles.

The Logic of Supranational Organization

2018 ◽  
Author(s):  
Morten Egeberg ◽  
Jarle Trondal
Keyword(s):  
European Commission ◽  
International Organizations ◽  
Organizational Innovation ◽  
The Other ◽  
Minor Role ◽  
Relative Importance ◽  
Institutional Affiliation ◽  
Organizational Behaviour ◽  
Organizational Position ◽  
A Minor

This chapter discusses ‘experiments’ in building supranational organization. Classical international organizations are formally governed by ministers who have their primary institutional affiliation at the national level. The European Commission, on the other hand, represents a notable organizational innovation in the way that executive politicians at the top, i.e. the commissioners, have their primary organizational affiliation at the supranational level. Thus, the Commission constitutes a ‘laboratory’ for experiments in supranational organization-building. The chapter asks what the relative importance is of nationality and organizational position as regards explaining organizational behaviour. The chapter shows that nationality plays a minor role among Commission officials. Nationality matters somewhat more regarding commissioners’ behaviour, but makes up only one of several components of their highly compound role, thus making behaviour at the top of the Commission qualitatively different from behaviour in e.g. the European Council.

The role of Hemolysis during Extracorporeal Homologous Liver Perfusion

1981 ◽  
Vol 4 (4) ◽  
pp. 178-185 ◽  
Author(s):  
M. Fischer ◽  
H.J. Jokiel ◽  
S. v. Sommoggy ◽  
T. Wustrow
Keyword(s):  
Liver Perfusion ◽  
Minor Role ◽  
Experimental Conditions ◽  
Volume Number ◽  
Plasma Hemoglobin ◽  
Priming Volume ◽  
Filtration Effect ◽  
Best Parameter ◽  
A Minor

The rate of hemolysis and the behaviour of platelets were investigated during extracorporeal pig liver perfusions. In 8 animals whose iliac vessels had been cannulated and which were perfused for 6 hours in our circuit, packed cell volume, number of red blood cells and concentration of hemoglobin changed moderately after hemodilution with the machine's priming volume. Similiar results were obtained in 10 pigs which were perfused with homologous isolated pig livers up to 6 hours. The best parameter to determine hemolysis was the plasma hemoglobin. Its level was twice as high as the initial value after mixture of the blood with the machine's priming volume in the iliac bypass experiments. Instead it remained practically unchanged throughout 6 hours of extracorporeal liver perfusions. The liver seemed to act as a filter under these experimental conditions. It had similar filtration effects on the enzymes LDH and alpha-HBDG which are set free in hemolysis. The decrease of platelets was more pronounced in extracorporeal liver perfusions than in iliac bypass experiments. Especially the functioning platelets decreased significantly in extracorporeal liver perfusions after 4–5 hours. The filtration effect of the liver seemed to be due to its intact RES. Xenogenous immunreactions played a minor role.

Electron affinity states of metal supported phthalocyanines measured by tunneling spectroscopy

2012 ◽  
Vol 16 (03) ◽  
pp. 273-281 ◽  
Author(s):  
K.W. Hipps ◽  
Ursula Mazur
Keyword(s):  
Gas Phase ◽  
Electron Affinity ◽  
Electron Tunneling ◽  
Tunneling Spectroscopy ◽  
Film Deposition ◽  
Solution Phase ◽  
Minor Role ◽  
Electron Affinities ◽  
Langmuir Blodgett ◽  
Metal Insulator Metal

Orbital Mediated Tunneling Spectroscopy OMTS (elastic electron tunneling) was employed in measuring electron affinity levels (EA) of unsubstituted, alkylated, sulfonated, and metalated phthalocyanines (Pc) adsorbed as single molecules or aggregates on metal substrates and imbedded in metal-insulator-metal (M-I-M) devices. MPc complexes were vapor deposited, solution phase doped, or transferred as Langmuir–Blodgett films. It was determined that while the nature of the substituents has a large effect on the gas phase electron affinities, they play a minimal role on the electron affinities of metal supported phthalocyanines. Moreover, the orientation of monolayer films and the method of film deposition (vapor, solution, Langmuir–Blodgett) also appear to play only a minor role in determining the electron affinities. Electrochemical reduction potentials obtained for the solution phase molecular systems are compared to the OMTS data and a strong correlation is observed. In contrast, the predicted EA values for the gas phase molecules show little correspondence with their OMTS equivalents for adsorbed phthalocyanines. Inelastic scattering from phthalocyanine π→π* transitions and metal centered d–d transitions are observed for chromophores imbedded in tunnel diodes. Both the observed lowest spin forbidden transitions and the calculated gas phase HOMO–LUMO gaps are only weakly affected by Pc substitution and surface orientation.

Thrombocytopenia Induced in Mice by Thromboplastin Infusion – Essential Role of the Third Complement Component

1978 ◽  
Vol 39 (03) ◽  
pp. 733-742
Author(s):  
Luis A Giraudo ◽  
Agustin P Dalmasso
Keyword(s):  
Blood Platelet ◽  
Total Serum ◽  
Minor Role ◽  
Slight Reduction ◽  
Experimental Conditions ◽  
Slow Infusion ◽  
A Minor ◽  
Deficient Mice

SummaryStudies were performed in mice to investigate the effects of the slow infusion of brain thromboplastin (tissue factor) on blood platelet levels. Thromboplastin caused pronounced thrombocytopenia in all strains of mice tested without histological evidence of intravascular coagulation. The role of the complement system in the thrombocytopenic response to thromboplastin administration was evaluated by using complement-deficient animals. Depending on experimental conditions, the degree of platelet reduction in C5-deficient mice was similar to or significantly lower than in normocomplementemic animals. C5-deficient mice reconstituted with mouse plasma or purified human C5 had a thrombocytopenic reaction identical to that of normocomplementemic controls. The thrombocytopenic response of B10.D2/new and old line mice could be abrogated by inactivating C3 with cobra venom factor prior to the administration of thromboplastin. We conclude that in mice C3 plays a central role in the thrombocytopenia induced by thromboplastin infusion, while C5 (and/or other late acting components) plays only a minor role. In vivo activation of complement by thromboplastin was indicated by the finding that thromboplastin infusion in B10.D2/new mice caused a significant reduction in total serum hemolytic complement and a slight reduction in C3 measured immunochemically. The platelet counts of uninjected B10.D2/new mice were slightly but significantly higher than in B10.D2/old mice.

Modelling of Hg(3P1) Photosensitization of SiH4 and Surface Reactions of the SiH3 Radical

1986 ◽  
Vol 75 ◽  
Author(s):  
Jérome Perrin ◽  
Ton Biroekhuizen
Keyword(s):  
Experimental Study ◽  
Gas Phase ◽  
Parallel Plate ◽  
Surface Reaction ◽  
Hydrogenated Amorphous Silicon ◽  
Film Deposition ◽  
Surface Processes ◽  
Precursor State ◽  
Parallel Plate Reactor ◽  
Hydrogenated Amorphous

AbstractWe present an experimental study and modelling of gas phase and surface processes involved in mercury-sensitized decomposition of SiH4, leading to hydrogenated amorphous silicon (a-Si:H) film deposition in a parallel plate reactor. The total surface reaction proabability β and the sticking probability s of SiH3 on a growing a-Si:H film are determined in the 40° – 350°C temperature domain. At 100°C β ≈ 0.1 ± 0.01 whereas s ≈ β/4 which reveals an intense radical recombination on the surface. Both β and s increase as a function of temperature. At 350°C β reaches 0.21±0.01. These results are interpreted by a precursor state model for SiH3 adsorption.

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