Precipitation in silicon: Microanalysis

1988 ◽  
Vol 46 ◽  
pp. 474-475
Author(s):  
R.W. Carpenter
Keyword(s):  
Transition Metals ◽  
Spatial Resolution ◽  
Thin Foil ◽  
Precipitation Reaction ◽  
High Current ◽  
Reaction Products ◽  
Carbon And Nitrogen ◽  
Dielectric Layers ◽  
Precipitation Processes ◽  
Areas Of Interest

Interest in precipitation processes in silicon appears to be centered on transition metals (for intrinsic and extrinsic gettering), and oxygen and carbon in thermally aged materials, and on oxygen, carbon, and nitrogen in ion implanted materials to form buried dielectric layers. A steadily increasing number of applications of microanalysis to these problems are appearing. but still far less than the number of imaging/diffraction investigations. Microanalysis applications appear to be paced by instrumentation development. The precipitation reaction products are small and the presence of carbon is often an important consideration. Small high current probes are important and cryogenic specimen holders are required for consistent suppression of contamination buildup on specimen areas of interest. Focussed probes useful for microanalysis should be in the range of 0.1 to 1nA, and estimates of spatial resolution to be expected for thin foil specimens can be made from the curves shown in Fig. 1.

Spatial resolution of X-ray microanalysis in thin foils

1978 ◽  
Vol 36 (1) ◽  
pp. 544-545
Author(s):  
R. Hutchings ◽  
I.P. Jones ◽  
M.H. Loretto ◽  
R.E. Smallman
Keyword(s):  
Spatial Resolution ◽  
Electron Probe ◽  
Beam Divergence ◽  
Inelastic Interaction ◽  
Specimen Thickness ◽  
High Current ◽  
Beam Spreading ◽  
X Ray ◽  
Thin Foils ◽  
Complex Calculation

There is increasing interest in X-ray microanalysis of thin specimens and the present paper attempts to define some of the factors which govern the spatial resolution of this type of microanalysis. One of these factors is the spreading of the electron probe as it is transmitted through the specimen. There will always be some beam-spreading with small electron probes, because of the inevitable beam divergence associated with small, high current probes; a lower limit to the spatial resolution is thus 2αst where 2αs is the beam divergence and t the specimen thickness.In addition there will of course be beam spreading caused by elastic and inelastic interaction between the electron beam and the specimen. The angle through which electrons are scattered by the various scattering processes can vary from zero to 180° and it is clearly a very complex calculation to determine the effective size of the beam as it propagates through the specimen.

scholarly journals A Mannose Family Phosphotransferase System Permease and Associated Enzymes Are Required for Utilization of Fructoselysine and Glucoselysine in Salmonella enterica Serovar Typhimurium

2015 ◽  
Vol 197 (17) ◽  
pp. 2831-2839 ◽  
Author(s):  
Katherine A. Miller ◽  
Robert S. Phillips ◽  
Paul B. Kilgore ◽  
Grady L. Smith ◽  
Timothy R. Hoover
Keyword(s):  
Nitrogen Source ◽  
Nitrogen Sources ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
Phosphotransferase System ◽  
Carbon And Nitrogen Sources ◽  
Content Type ◽  
Carbon And Nitrogen ◽  
Serovar Typhimurium ◽  
Food Borne Illness

ABSTRACTSalmonella entericserovar Typhimurium, a major cause of food-borne illness, is capable of using a variety of carbon and nitrogen sources. Fructoselysine and glucoselysine are Maillard reaction products formed by the reaction of glucose or fructose, respectively, with the ε-amine group of lysine. We report here thatS. Typhimurium utilizes fructoselysine and glucoselysine as carbon and nitrogen sources via a mannose family phosphotransferase (PTS) encoded bygfrABCD(glucoselysine/fructoselysine PTS components EIIA, EIIB, EIIC, and EIID; locus numbers STM14_5449 to STM14_5454 inS. Typhimurium 14028s). Genes coding for two predicted deglycases within thegfroperon,gfrEandgfrF, were required for growth with glucoselysine and fructoselysine, respectively. GfrF demonstrated fructoselysine-6-phosphate deglycase activity in a coupled enzyme assay. The biochemical and genetic analyses were consistent with a pathway in which fructoselysine and glucoselysine are phosphorylated at the C-6 position of the sugar by the GfrABCD PTS as they are transported across the membrane. The resulting fructoselysine-6-phosphate and glucoselysine-6-phosphate subsequently are cleaved by GfrF and GfrE to form lysine and glucose-6-phosphate or fructose-6-phosphate. Interestingly, althoughS. Typhimurium can use lysine derived from fructoselysine or glucoselysine as a sole nitrogen source, it cannot use exogenous lysine as a nitrogen source to support growth. Expression ofgfrABCDEFwas dependent on the alternative sigma factor RpoN (σ54) and an RpoN-dependent LevR-like activator, which we designated GfrR.IMPORTANCESalmonellaphysiology has been studied intensively, but there is much we do not know regarding the repertoire of nutrients these bacteria are able to use for growth. This study shows that a previously uncharacterized PTS and associated enzymes function together to transport and catabolize fructoselysine and glucoselysine. Knowledge of the range of nutrients thatSalmonellautilizes is important, as it could lead to the development of new strategies for reducing the load ofSalmonellain food animals, thereby mitigating its entry into the human food supply.

Microscopic Observation of Photocatalytic Reaction Using Microelectrode: Spatial Resolution for Reaction Products Distribution

1995 ◽  
Vol 24 (11) ◽  
pp. 979-980 ◽  
Author(s):  
Katsuyoshi Ikeda ◽  
Hideki Sakai ◽  
Ryo Baba ◽  
Kazuhito Hashimoto ◽  
Akira Fujishima
Keyword(s):  
Spatial Resolution ◽  
Microscopic Observation ◽  
Photocatalytic Reaction ◽  
Reaction Products

First row transition metals on the ethanol Guerbet reaction: products distribution and structural behavior of mixed metal oxides as catalysts

2021 ◽  
pp. 118272
Author(s):  
Gustavo Metzker ◽  
Jorge Andres Mora Vargas ◽  
Livia Padilha de Lima ◽  
Olavo Micali Perrone ◽  
Marcos Rechi Siqueira ◽  
...  
Keyword(s):  
Transition Metals ◽  
Metal Oxides ◽  
Structural Behavior ◽  
Mixed Metal Oxides ◽  
Reaction Products ◽  
Mixed Metal ◽  
Guerbet Reaction

The spatial resolution of x-ray microanalysis in thin foils

1991 ◽  
Vol 49 ◽  
pp. 472-473
Author(s):  
D. B. Williams ◽  
J. R. Michael ◽  
J. I. Goldstein ◽  
A. D. Romig
Keyword(s):  
Spatial Resolution ◽  
Thin Foil ◽  
Beam Specimen ◽  
Beam Diameter ◽  
Worst Case ◽  
X Ray ◽  
Thin Foils ◽  
Elastic Scatter ◽  
Electron Beam Diameter ◽  
Beam Broadening

The spatial resolution of x-ray microanalysis in a thin foil is determined by the size of the beam-specimen interaction volume. This volume is a combination of the incident electron beam diameter (d) and the beam broadening (b) due to elastic scatter within the specimen. Definitions of spatial resolution have already been proposed on this basis but all present a worst case value for the resolution based on the dimensions of the beam emerging from the exit face of the foil.

Molten potassium pyrosulfate: Reactions of metals

1982 ◽  
Vol 35 (2) ◽  
pp. 437 ◽  
Author(s):  
AN Ford ◽  
BJ Meehan ◽  
SA Tariq
Keyword(s):  
Sulfur Dioxide ◽  
Transition Metals ◽  
Reaction Products ◽  
Cu And Zn

The reactions of the fist row transition metals and zinc with molten potassium pyrosulfate were investigated. It was found that Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn were oxidized to TiIV, VIV, CrIII, MnII, FeIII, CoII, NiII, CuII and Zn11 respectively and the reaction products of the pyrosulfate melt consisted of sulfate and sulfur dioxide. The stoichiometries of these reactions have been established.

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