Systematics of Silicide Formation by High Dose Miplantation of Transition Metals into Si

1986 ◽  
Vol 74 ◽  
Author(s):  
F. Namavar ◽  
F. H. Sanchez ◽  
J. I. Budnick ◽  
A. H. Fasihuddin ◽  
H. C. Hayden
Keyword(s):  
Room Temperature ◽  
Hexagonal Structure ◽  
High Dose ◽  
List Type ◽  
Type Number ◽  
Silicide Formation ◽  
Metal Thin Films ◽  
X Ray ◽  
Cubic Structure ◽  
Fe Implantation

AbstractWe have systematically studied the formation of transition-metal thin films by high dose (up to 1018 ions/cm2) implantation of Ti, V, Cr, Mn, Fe, Co, Ni and Nb at room temperature and 350°C into Si <100>.For implantation at 350°C, our results, as obtained by Rutherford backscattering, X-ray diffractometry and Read Camera measurements, indicate that one can categorize these metals into two groups: 1.a chromium group which includes V, Cr, Nb, Ti and Mn. Metals V, Cr and Nb form compounds (VSi2, CrSi2. NbSi2) with a hexagonal structure of the CrSi2 type whereas Ti and Mn both form compounds (Ti5Si3, Mn5Si3) with a hexagonal structure of the Mn5Si2 type.2.an iron group which includes Fe, Co and Ni. These metals form compounds (FeSi, CoSi, NiSi) with a cubic structure of the FeSi type.In this paper the experimental results for Cr and Fe implantation at room temperature and 350°C will be discussed.

Hydration Chamber for Jeolco 200 Kv Microscope

1970 ◽  
Vol 28 ◽  
pp. 542-543
Author(s):  
V. R. Matricardi ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscope ◽  
Water Vapor ◽  
Vapor Pressure ◽  
Pressure Gradient ◽  
Room Temperature ◽  
List Type ◽  
Type Number ◽  
Equilibrium Vapor Pressure

In order to observe room temperature hydrated specimens in an electron microscope, the following conditions should be satisfied: The specimen should be surrounded by water vapor as close as possible to the equilibrium vapor pressure corresponding to the temperature of the specimen.The specimen grid should be inserted, focused and photo graphed in the shortest possible time in order to minimize dehydration.The full area of the specimen grid should be visible in order to minimize the number of changes of specimen required.There should be no pressure gradient across the grid so that specimens can be straddled across holes.Leakage of water vapor to the column should be minimized.

Fluorescence effects in quantitative microprobe analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 188-189
Author(s):  
S.J.B. Reed
Keyword(s):  
Microprobe Analysis ◽  
Depth Distribution ◽  
Exciting Radiation ◽  
Primary Radiation ◽  
List Type ◽  
Type Number ◽  
Computing Power ◽  
X Ray ◽  
Fluorescent Radiation

Characteristic fluorescenceThe theory of characteristic fluorescence corrections was first developed by Castaing. The same approach, with an improved expression for the relative primary x-ray intensities of the exciting and excited elements, was used by Reed, who also introduced some simplifications, which may be summarized as follows (with reference to K-K fluorescence, i.e. K radiation of element ‘B’ exciting K radiation of ‘A’):1.The exciting radiation is assumed to be monochromatic, consisting of the Kα line only (neglecting the Kβ line).2.Various parameters are lumped together in a single tabulated function J(A), which is assumed to be independent of B.3.For calculating the absorption of the emerging fluorescent radiation, the depth distribution of the primary radiation B is represented by a simple exponential.These approximations may no longer be justifiable given the much greater computing power now available. For example, the contribution of the Kβ line can easily be calculated separately.

Interactive multiple area spectrum integration (MASI)

1994 ◽  
Vol 52 ◽  
pp. 942-943
Author(s):  
John A. Hunt ◽  
Richard D. Leapman ◽  
David B. Williams
Keyword(s):  
Image Processing ◽  
Low Dose ◽  
Routine Analysis ◽  
Reference Image ◽  
Area Spectrum ◽  
List Type ◽  
Type Number ◽  
Image Processor ◽  
X Ray ◽  
Scanning Path

Interactive MASI involves controlling the raster of a STEM or SEM probe to areas predefined byan integration mask which is formed by image processing, drawing or selecting regions manually. EELS, x-ray, or other spectra are then acquired while the probe is scanning over the areas defined by the integration mask. The technique has several advantages: (1) Low-dose spectra can be acquired by averaging the dose over a great many similar features. (2) MASI can eliminate the risks of spatial under- or over-sampling of multiple, complicated, and irregularly shaped objects. (3) MASI is an extremely rapid and convenient way to record spectra for routine analysis. The technique is performed as follows:Acquire reference imageOptionally blank beam for beam-sensitive specimensUse image processor to select integration mask from reference imageCalculate scanning path for probeUnblank probe (if blanked)Correct for specimen drift since reference image acquisition

Photoluminescence Enhancement of CdS Nanocrystals Fabricated on Dithiocarbamate Functionalized PET Substrates

2012 ◽  
Vol 512-515 ◽  
pp. 1511-1515
Author(s):  
Chun Lin Zhao ◽  
Li Xing ◽  
Xiao Hong Liang ◽  
Jun Hui Xiang ◽  
Fu Shi Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hexagonal Structure ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Morphological Studies ◽  
Transmission Electron

Cadmium sulfide (CdS) nanocrystals (NCs) were self-assembled and in-situ immobilized on the dithiocarbamate (DTCs)-functionalized polyethylene glycol terephthalate (PET) substrates between the organic (carbon disulfide diffused in n-hexane) –aqueous (ethylenediamine and Cd2+ dissolved in water) interface at room temperature. Powder X-ray diffraction measurement revealed the hexagonal structure of CdS nanocrystals. Morphological studies performed by scanning electron microscopy (SEM) and high-resolution transmission electron microscope (HRTEM) showed the island-like structure of CdS nanocrystals on PET substrates, as well as energy-dispersive X-ray spectroscopy (EDS) confirmed the stoichiometries of CdS nanocrystals. The optical properties of DTCs modified CdS nanocrystals were thoroughly investigated by ultraviolet-visible absorption spectroscopy (UV-vis) and fluorescence spectroscopy. The as-prepared DTCs present intrinsic hydrophobicity and strong affinity for CdS nanocrystals.

Directional Persistence in the Rewarded Alternation Model of Obsessive-compulsive Disorder is Responsive to both Dopaminergic and Serotonergic Manipulations

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
D. Kontis ◽  
V. Boulougouris ◽  
S. Papadopoulos ◽  
V.-M. Papakosta ◽  
S. Kalogerakou ◽  
...  
Keyword(s):  
Obsessive Compulsive Disorder ◽  
Low Dose ◽  
Receptor Activation ◽  
Common Mechanism ◽  
High Dose ◽  
List Type ◽  
Type Number ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
Serotonin Agonist

Rationale:In the rewarded alternation model of obsessive compulsive disorder (OCD), the serotonin agonist m-chlorophenylpiperazine (mCPP) increases persistent behaviour, while chronic pretreatment with selective serotonin reuptake inhibitor (SSRI-fluoxetine) but not benzodiazepine or desipramine abolishes mCPP effects. However, we noted that acute SSRI administration also causes transient persistence increases, counteracted by mCPP pretreatment.Objectives:This studya.further explores the apparent cross-tolerance between fluoxetine and mCPP andb.extends the model by investigating its sensitivity to dopaminergic manipulations (D2,3 agonism - quinpirole).Methods:In both experiments, baseline and drug testing was carried out under daily T-maze alternation training.Exp.1:Matched group (n=8) pairs of rats received one of the following 20-day pretreatments (daily intraperitoneal administration):1.saline,2.low-dose fluoxetine (2.5mg/kg),3.low-dose mCPP (0.5mg/kg) or4.combined fluoxetine+mCPP.One group per pretreatment then received a 4-day challenge with high-dose fluoxetine (10mg/kg), the other with high-dose mCPP (2.5mg/kg).Exp.2:One group (n=12) of rats received 20-day treatment with saline, another with quinpirole (0.5 mg/kg).Results:Exp.1:Saline and low-dose mCPP- or fluoxetine-pretreated animals showed significant persistence increases under both challenges, while combined low-dose fluoxetine+mCPP pretreatment afforded full protection from either challenge.Exp.2:Quinpirole significantly increased directional persistence after 13 administration days.Conclusions:These results establish the sensitivity of the rewarded alternation OCD model to D2,3receptor activation, thereby extending its profile of pharmacological isomorphism with OCD. Furthermore, they suggest a common mechanism of action of an SSRI and a serotonin agonist in the control of directional persistence.

X-ray Diffraction Studies of Solid Solutions of Pentaglycerine-Neopentylglycol

1988 ◽  
Vol 32 ◽  
pp. 609-616 ◽  
Author(s):  
D. Chandra ◽  
C. S. Barrett ◽  
D. K. Benson
Keyword(s):  
Crystal Structure ◽  
Energy Storage ◽  
Hydrogen Bonds ◽  
Solid Solutions ◽  
Room Temperature ◽  
Energy Storage Materials ◽  
Anisotropic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Structure

AbstractAn array of molecules that is anisotropic in the extreme has been discovered in certain thermal-energy storage materials and is reported here: neopentylglycol (NPG) and NPG-rich solid solutions with pentaglycerine (PG) have a crystal structure, stable at room temperature, that consists of bimolecular chains of molecules that are all unidirectionally aligned throughout a crystal. There are hydrogen bonds between every molecule in one chain and its neighbors in that chain, but none between molecules of one chain and any molecules of the neighboring parallel chains. Thus there are strong intermolecular bonds along each chain and only weaker bonds between the chains. The structure has been determined by using modern single crystal techniques with 529 independent reflections from a crystal of NPG (C5H12O2). The structure is monoclinic with space group P21/c - C2h5. This anisotropic structure transforms to a cubic structure at higher temperatures.

scholarly journals Solar X radiation

1965 ◽  
Vol 23 ◽  
pp. 45-52 ◽  
Author(s):  
C. de Jager
Keyword(s):  
Electromagnetic Radiation ◽  
Gamma Rays ◽  
Electronic Transitions ◽  
List Type ◽  
X Rays ◽  
Type Number ◽  
X Ray ◽  
Image Position ◽  
Electron Shells

X-ray bursts are defined as electromagnetic radiation originating from electronic transitions involving the lowest electron shells; gamma rays are of nuclear origin. Solar gamma rays have not yet been discovered.According to the origin we have : 1.Quasi thermal X-rays, emitted by (a) the quiet corona, (b) the activity centers without flares, and (c) the X-ray flares.2.Non-thermal X-ray bursts; these are always associated with flares.The following subdivision is suggested for flare-associated bursts :

Silicide Formation in High-Dose Fe-Implanted Silicon

1991 ◽  
Vol 235 ◽  
Author(s):  
Z. Tan ◽  
F. Namavar ◽  
S. M. Heald ◽  
J. I. Budnick ◽  
F. H. Sanchez
Keyword(s):  
Fine Structure ◽  
Single Phase ◽  
Rutherford Backscattering Spectrometry ◽  
High Dose ◽  
Silicide Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Implantation Damage ◽  
X Ray Absorption ◽  
Post Implantation

ABSTRACTWe have studied the silicide formation in Fe-implanted Si(100), with 1×1017-1×1018 Fe/cm2, using extended x-ray-absorption fine structure (EXAFS), x-ray diffraction and Rutherford backscattering spectrometry (RBS) methods. In the samples as-implanted at 350 °C, no silicide was observed at doses below 3×1017 Fe/cm2. At 5×1017 Fe/cm2, both α-FeSi2 and (β-FeSi2 form but α-FeSi2 appears to be the majority phase. As the dose increases to 7×1017 and above, ordered FeSi forms, but implantation damage is severe and a large number of Fe atoms are in very disordered environments. In addition to FeSi, Fe5Si3 was also observed in the 1×1018 Fe/cm2 sample. Upon post-implantation annealing at 700 °C or 900 °C, single phase P-FeSi2 was obtained independent of the dosage.

scholarly journals KARAKTERISASI ABU KAYU MERBAU (Intsia, spp.): PENGARUH TEMPERATUR DAN LAMA KALSINASI

2019 ◽  
Vol 15 (1) ◽  
pp. 30-38
Author(s):  
Darma Santi ◽  
Jacson Victor Morin
Keyword(s):  
Calcination Temperature ◽  
Wood Ash ◽  
Hexagonal Structure ◽  
Rhombohedral Structure ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Cubic Structure

Characterization of merbau wood ash (Intsia, spp.) due to the influence of temperature and time of calcination has been studied. The variations in calcination temperature were 500 ᴼC (as M500) and 600 ᴼC (as M600), while the variations in the duration of calcination were 1, 2, and 3 hours, noted as M1, M2, and M3, respectively. Characterization was carried out using X-ray diffraction (XRD) and spectroscopic analysis using FT-IR. XRD results identified the presence of CaCO3 species (rhombohedral structure) and K2Si4O9 species with a hexagonal structure on M500. The M600 species identified Si (cubic structure), SiO2 (cubic structure), K2Si4O9 (hexagonal structure), and CaCO3 (rhombohedral structure). In general, the calcination temperature increases the crystallinity of several compounds contained in merbau wood ash. The length of time calcination reduces the absorption peak due to the decomposition and adsorption reactions of the presence of water molecules bound to the ash material of merbau wood (Intsia, spp).

scholarly journals A new catalogue of quasi-stellar objects

1986 ◽  
Vol 119 ◽  
pp. 51-52
Author(s):  
A. Hewitt ◽  
G. Burbidge
Keyword(s):  
Seyfert Galaxies ◽  
List Type ◽  
Type Number ◽  
Stellar Objects ◽  
Bl Lac Objects ◽  
X Ray ◽  
Bl Lac ◽  
Similar Information ◽  
Quasi Stellar Objects ◽  
Objective Prism

We have prepared a new catalogue of QSOs and BL Lac objects containing approximately 3400 entries. A complete update of the Hewitt-Burbidge (1980) catalogue has been made with approximately another 2000 objects with known redshifts added. The references to discovery, magnitudes, redshifts, color, spectra and polarimetry have been updated for the objects listed in 1980, and complete new references are included for the new objects. In addition to the basic optical information, the new catalogue also contains X-ray, radio and infrared information for all objects. Absorption redshifts are listed when they are available. A supplementary catalogue which is now in preparation will contain similar information for objects described variously as Seyfert galaxies, N systems and AGNs. In doubtful cases we have used the operational dividing line ƶ = 0.1. All objects with ƶ < 0.1 are put in the supplementary catalogue unless their discoverers have unambiguously defined them as QSOs. With approximately twice as many objects included it is interesting to note that: a)There are still very few genuine BL Lac objects, ∼100.b)The largest number of additions has come from identifications using the objective prism-grism techniques.

Sign in / Sign up

Export Citation Format

Share Document