scholarly journals Study of Polarographic Anodic Wave Controlled by the Rate of Precipitation Reaction in the Presence of Citrate Ion

1990 ◽  
Vol 63 (11) ◽  
pp. 3183-3188 ◽  
Author(s):  
Kenji Kikuchi ◽  
Teisuke Murayama
Keyword(s):  
Precipitation Reaction ◽  
Anodic Wave

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.

A TEM investigation of a hyper-eutectic lead-tin alloy

1988 ◽  
Vol 46 ◽  
pp. 562-563
Author(s):  
John A. Sutliff
Keyword(s):  
Volume Diffusion ◽  
Eutectic Mixture ◽  
Precipitation Reaction ◽  
Directionally Solidified ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Diffusion Controlled ◽  
Discontinuous Precipitation Reaction ◽  
Controlled Precipitation

Near-eutectic Pb-Sn alloys are important solders used by the electronics industry. In these solders, the eutectic mixture, which solidifies last, is the important microstructural consituent. The orientation relation (OR) between the eutectic phases has previously been determined for directionally solidified (DS) eutectic alloys using x-ray diffraction or electron chanelling techniques. In the present investigation the microstructure of a conventionally cast, hyper-eutectic Pb-Sn alloy was examined by transmission electron microscopy (TEM) and the OR between the eutectic phases was determined by electron diffraction. Precipitates of Sn in Pb were also observed and the OR determined. The same OR was found in both the eutectic and precipitation reacted materials. While the precipitation of Sn in Pb was previously shown to occur by a discontinuous precipitation reaction,3 the present work confirms a recent finding that volume diffusion controlled precipitation can also occur.Samples that are representative of the solder's cast microstructure are difficult to prepare for TEM because the alloy is multiphase and the phases are soft.

Illite-smectites and the influence of burial diagenesis on the geochemical cycling of nitrogen

Clay Minerals ◽  
1998 ◽  
Vol 33 (4) ◽  
pp. 539-546 ◽  
Author(s):  
P. A. Schroeder ◽  
A. A. McLain
Keyword(s):  
Reaction Mechanisms ◽  
Ostwald Ripening ◽  
Precipitation Reaction ◽  
Oil Well ◽  
Burial Diagenesis ◽  
Fixed Nitrogen ◽  
Geochemical Cycling ◽  
Oil Generation ◽  
Fraction Increase ◽  
Changing Rate

AbstractFixed nitrogen in illite-smectites (I-S) has been measured for Miocene shales from a Gulf of Mexico oil well. Fixed N values for the <0.2 µm fraction increase with depth from 150 ppm (1000 m) to a maximum of 360 ppm (3841 m). This increase is coincident with illitization from 41% I in I-S to 75% I in I-S. Below 3841 m, fixed N values decrease to 190 ppm (4116 m) while I-S is maintained with a slight increase from 77 to 82%. The changes in fixed N with increasing illitization are consistent with the notion that illitization proceeds via both transformation and dissolution/ precipitation reaction mechanisms. The trend of decreasing fixed N in illitic I-S is compatible with surface-controlled crystal growth and Ostwald ripening mechanisms for illitization. The trend may also be linked to the timing of maximum NH] release from kerogen maturation during oil generation. The changing rate of NH+4 liberation from organic matter and multiple illitization reaction mechanisms can result in complex N geochemical cycling pathways throughout early diagenesis to metamorphism.

About the precipitation reaction in trichinosis

1934 ◽  
Vol 30 (11-12) ◽  
pp. 1205-1205
Author(s):  
A. Trawinsky ◽  
S. Maternoroska
Keyword(s):  
Hydrochloric Acid ◽  
Physiological Solution ◽  
Precipitation Reaction ◽  
Usual Dose ◽  
Series Of Experiments

To obtain precipitating sera, rabbits were infected per os with trichins. The usual dose used was 250 to 1000 trichins in one or more doses. The exsanguination of rabbits was performed at different times, from the 3rd to the 26th day, and in one series of experiments even on the 50th day. At the same time, exsanguinated rabbits were examined to determine whether the infection had resulted in trichinosis. Sera of only those rabbits whose organs or intestines were found to contain trichins were tested. The antigen was prepared as follows: the muscles of rabbits infected with trichins were pulverized and then physiological solution with 0.4% pepsin solution and 0.25/o hydrochloric acid was added.

Electrolytic phase extraction: a useful technique to evaluate precipitates in nitinol

2012 ◽  
Vol 27 (2) ◽  
pp. 136-139 ◽  
Author(s):  
Roy G. Baggerly
Keyword(s):  
Shape Memory ◽  
Matrix Composition ◽  
Precipitation Reaction ◽  
Phase Extraction ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Solubility Range ◽  
Two Samples ◽  
Rich Alloy ◽  
Rich Side

Nitinol is a shape memory alloy based on the inter-atomic compound having a composition of 50  at% each of Ni and Ti, NiTi. The shape memory effect results from a reversible martensitic phase transformation. An increasing solubility range with temperature on the Ni-rich side can produce a precipitation reaction resulting in a slight matrix composition adjustment with appropriate heat treatment. Electrolytic phase extraction (Andrews and Hughes, 1957) is used to evaluate the secondary phases in the alloy and Ti2Ni and TiC are positively identified using powder wide-angle X-ray diffraction procedures. Two samples of an Ni-rich alloy at 57 and 60 at% are also analyzed. These Ni-rich samples show Ti2Ni and an additional phase, Ni3Ti.

The composition and structure of SIPOS: A high spatial resolution electron microscopy study

1993 ◽  
Vol 8 (11) ◽  
pp. 2893-2901 ◽  
Author(s):  
M. Catalano ◽  
M.J. Kim ◽  
R.W. Carpenter ◽  
Das K. Chowdhury ◽  
Joe Wong
Keyword(s):  
Electron Microscopy ◽  
Oxygen Concentration ◽  
High Resolution Electron Microscopy ◽  
Microscopy Study ◽  
Isothermal Transformation ◽  
Electron Microscopy Study ◽  
Precipitation Reaction ◽  
Free Zone ◽  
Resolution Electron ◽  
Chemical Distribution

The nanostructure and chemical distribution in semi-insulating polycrystalline oxygen-doped silicon (SIPOS) deposited on (001) Si and its isothermal transformation behavior at 900 °C were investigated by high resolution electron microscopy (HREM) and electron energy loss nanospectroscopy (EELS). The structure of the as-deposited film, which contained 15 at. % oxygen, was amorphous. No evidence for nanocrystalline second phases was found. It was similar in appearance to amorphous silicon. After annealing for 30 min at 900 °C in an inert environment (N2), a dispersion of small nanocrystals, identified as silicon by imaging, diffraction and EELS, formed in the amorphous SIPOS matrix, with a thin precipitate free zone (PFZ) adjacent to the Si substrate. The SIPOS matrix oxygen concentration increased to 36 at. % and the matrix remained amorphous after annealing. No other phases were observed in annealed specimens. Changes in Si–L near edge fine structure and low loss peaks in EELS spectra from SIPOS with increasing oxygen concentration indicated that it is a solid solution supersaturated with silicon. Microstructures indicated that the Si nanocrystals formed during a homogeneous precipitation reaction.

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