scholarly journals Neon isotopes in individual presolar low-density graphite grains from the Orgueil meteorite

2018 ◽  
Vol 53 (11) ◽  
pp. 2327-2342 ◽  
Author(s):  
Philipp R. Heck ◽  
Manavi Jadhav ◽  
Matthias M. M. Meier ◽  
Teruyuki Maruoka ◽  
Sachiko Amari ◽  
...  
Keyword(s):  
Low Density ◽  
Density Graphite

Low‐Density Graphite Grains and Mixing in Type II Supernovae

1999 ◽  
Vol 510 (1) ◽  
pp. 325-354 ◽  
Author(s):  
Claudia Travaglio ◽  
Roberto Gallino ◽  
Sachiko Amari ◽  
Ernst Zinner ◽  
Stan Woosley ◽  
...  
Keyword(s):  
Low Density ◽  
Type Ii ◽  
Density Graphite

scholarly journals Pre-solar grains from supernovae and novae

2006 ◽  
Vol 2 (14) ◽  
pp. 349-352
Author(s):  
Sachiko Amari ◽  
Katharina Lodders
Keyword(s):  
Silicon Carbide ◽  
Fine Tuning ◽  
Isotopic Ratios ◽  
Low Density ◽  
Density Graphite ◽  
Neutron Burst ◽  
Isotopic Anomalies

AbstractPre-solar grains from supernova ejecta – silicon carbide of type X, Si3N4 and low-density graphite – are characterized by Si isotopic anomalies (mainly 28Si excesses), low 14N/15N, high 26Al/27 Al ratios, and occasionally by excesses in 44Ca (from 44Ti decay). Overall isotopic features of these SiC and graphite grains can be explained by mixing of inner Si-rich zones and the outer C-and He-rich zones, but supernova models require fine tuning to account for 14N/15N and 29Si/28Si ratios of the grains. Isotopic ratios of Zr, Mo and Ba in SiC X grains may be explained by a neutron burst model. Some of the pre-solar nanodiamonds require a supernova origin to explain measured xenon isotopic ratios. Only a few nova grain candidates, with low 12C/13C, 14N/15N, and high 26Al/27 Al ratios, have been identified.

Appearance of the supercritical state of carbon in the laser evaporation of low-density graphite foil

1998 ◽  
Vol 8 (6) ◽  
pp. 212-213 ◽  
Author(s):  
Sergei I. Kudryashov ◽  
Sergei G. Ionov ◽  
Alexander A. Karabutov ◽  
Nikita B. Zorov
Keyword(s):  
Laser Evaporation ◽  
Low Density ◽  
Supercritical State ◽  
Graphite Foil ◽  
Density Graphite

scholarly journals Modeling of a Dynamic Thermal Load Generated by a 7TeV Proton Beam Impacting the Beam Dump of the Large Hadron Collider at CERN

2018 ◽  
Vol 183 ◽  
pp. 01065
Author(s):  
Tobias Polzin ◽  
Antonio Peiillo-Marcone ◽  
Laura Bianchi ◽  
Marco Calviani ◽  
Matthias Frankl ◽  
...  
Keyword(s):  
Large Hadron Collider ◽  
Proton Beam ◽  
Hadron Collider ◽  
Particle Beam ◽  
High Energy ◽  
Material Behavior ◽  
General Nature ◽  
Low Density ◽  
Beam Dump ◽  
Density Graphite

The two beam dumps of the Large Hadron Collider (LHC), made up mostly of low-density graphite, are responsible for absorbing the high-energy particle beams when ejected from the accelerator. In the frame-work of the project to improve the luminosity in the LHC, the beam intensity will be increased by a factor of around two in the coming years. The dominant load on the dump assembly is the energy deposited in the material by the 7 TeV proton beam. Thermomechanical simulations have to be performed to ensure the safe operation of the dump through assessing the integrity in the future. To date, the particle beam contains an average energy of 370 MJ, which is sent to the dump in a sweep movement within around 80 µs. Based on the large dimensions of the dump core and considering the highly dynamic nature of this load, an explicit code like LS-Dyna® was deemed to be best suited for these studies. This paper presents the methodology proposed to model the discrete time structure of the load, caused by the interaction between the particle beam and the dump. Results of the application of this technique, to determine the temperature, stresses and wave propagation on the downstream wall of this device, are described here. In addition to the methodology of the load application, the results of standard quasi-static material tests on the low-density graphite material in the beam dump are presented, to assess the general nature of the material behavior. These experiments will be the basis for a dynamic test campaign to construct a comprehensive material model, as the graphite used in this device has never been fully characterized under such loading conditions.

scholarly journals Third-generation oxygen amperometric biosensor based on Trametes hirsuta laccase covalently bound to graphite electrode

2015 ◽  
Vol 69 (1) ◽  
Author(s):  
Cristina Gutierrez-Sanchez ◽  
Sergey Shleev ◽  
Antonio L. De Lacey ◽  
Marcos Pita
Keyword(s):  
Electron Transfer ◽  
Graphite Electrode ◽  
Direct Electron Transfer ◽  
Low Density ◽  
Third Generation ◽  
Time Analysis ◽  
Trametes Hirsuta ◽  
Graphite Electrodes ◽  
Real Time Analysis ◽  
Density Graphite

AbstractThe response of low-density graphite electrodes hosting Trametes hirsuta laccase in a direct electron transfer regime is presented for real-time analysis of O

Application of Improved Voltage Compensation in the SEM to Imaging of Organic Materials

1973 ◽  
Vol 31 ◽  
pp. 444-445
Author(s):  
P.J. Killingworth ◽  
M. Warren
Keyword(s):  
Electron Beam ◽  
Organic Materials ◽  
Operating Parameters ◽  
Low Density ◽  
Beam Diameter ◽  
Incident Electron Beam ◽  
Specimen Material ◽  
Voltage Compensation ◽  
Selection Of ◽  
Scanning Electron

Ultimate resolution in the scanning electron microscope is determined not only by the diameter of the incident electron beam, but by interaction of that beam with the specimen material. Generally, while minimum beam diameter diminishes with increasing voltage, due to the reduced effect of aberration component and magnetic interference, the excited volume within the sample increases with electron energy. Thus, for any given material and imaging signal, there is an optimum volt age to achieve best resolution.In the case of organic materials, which are in general of low density and electric ally non-conducting; and may in addition be susceptible to radiation and heat damage, the selection of correct operating parameters is extremely critical and is achiev ed by interative adjustment.

Quantitative defect studies in semiconductor TEM samples prepared by low angle ion milling

1995 ◽  
Vol 53 ◽  
pp. 512-513
Author(s):  
L. Mulestagno ◽  
J.C. Holzer ◽  
P. Fraundorf
Keyword(s):  
Sample Preparation ◽  
Milling Time ◽  
High Density ◽  
Low Density ◽  
Ion Milling ◽  
High Quality ◽  
Variable Angle ◽  
Major Disadvantage ◽  
Induced Defects

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).

Intralysosomal Accumulation of Colloidal Gold-Low Density Lipoprotein Conjugates in Chloroquine-Treated Fibroblasts

1985 ◽  
Vol 43 ◽  
pp. 546-547 ◽  
Author(s):  
Dean A. Handley ◽  
Cynthia M. Arbeeny ◽  
Larry D. Witte
Keyword(s):  
Colloidal Gold ◽  
Cultured Cells ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Coated Vesicle ◽  
Low Density ◽  
Cholesterol Esters ◽  
Cultured Fibroblasts ◽  
Surface Receptors ◽  
Ldl Particles

Low density lipoproteins (LDL) are the major cholesterol carrying particles in the blood. Using cultured cells, it has been shown that LDL particles interact with specific surface receptors and are internalized via a coated pit-coated vesicle pathway for lysosomal catabolism. This (Pathway has been visualized using LDL labeled to ferritin or colloidal gold. It is now recognized that certain lysomotropic agents, such as chloroquine, inhibit lysosomal enzymes that degrade protein and cholesterol esters. By interrupting cholesterol ester hydrolysis, chloroquine treatment results in lysosomal accumulation of cholesterol esters from internalized LDL. Using LDL conjugated to colloidal gold, we have examined the ultrastructural effects of chloroquine on lipoprotein uptake by normal cultured fibroblasts.

ALCHEMI of B2-Ordered Fe50Al45Me5 alloys

1996 ◽  
Vol 54 ◽  
pp. 548-549
Author(s):  
Ian M. Anderson
Keyword(s):  
Room Temperature ◽  
Iron Aluminide ◽  
Low Density ◽  
Intermetallic Alloys ◽  
Practical Applications ◽  
Alloying Additions ◽  
Site Distribution ◽  
Good Corrosion Resistance ◽  
Room Temperature Ductility ◽  
The Matrix

B2-ordered iron aluminide intermetallic alloys exhibit a combination of attractive properties such as low density and good corrosion resistance. However, the practical applications of these alloys are limited by their poor fracture toughness and low room temperature ductility. One current strategy for overcoming these undesirable properties is to attempt to modify the basic chemistry of the materials with alloying additions. These changes in the chemistry of the material cannot be fully understood without a knowledge of the site-distribution of the alloying elements. In this paper, the site-distributions of a series of 3d-transition metal alloying additions in B2-ordered iron aluminides are studied with ALCHEMI.A series of seven alloys of stoichiometry Fe50AL45Me5, with Me = {Ti, V, Cr, Mn, Co, Ni, Cu}, were prepared with identical heating cycles. Microalloying additions of 0.2% B and 0.1% Zr were also incorporated to strengthen the grain boundaries, but these alloying additions have little influence on the matrix chemistry and are incidental to this study.

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