scholarly journals In-situ TEM Investigation of Solid Phase Transformations and Reactions

2021 ◽  
Author(s):  
Klára Hajagos-Nagy
Keyword(s):  
Solid Phase ◽  
Multicomponent System ◽  
Internal Standard ◽  
Solute Concentration ◽  
In Situ Tem ◽  
Phase Identification ◽  
Internal Standard Method ◽  
Carbide Phases ◽  
Different Temperatures

In this paper, an example of phase analysis during annealing is presented using in-situ TEM. The example is demonstrated on amorphous Cu-Mn/C thin films focusing on phase identification in a multicomponent system. The transient states following the crystallization of the amorphous Cu-Mn alloy and the reaction with the C substrate were analyzed by evaluating the diffraction patterns recorded at different temperatures. The camera constant was calibrated using the internal standard method. The change in composition of the Cu(Mn) solid solution was calculated by separating the effect of thermal expansion and solute concentration. Identification of the forming phases was aided by analyzing and comparing the probability of formation of all phases in the Cu-Mn-C-O system. After the crystallization of amorphous Cu-Mn alloy into Cu(Mn) and α-Mn-based solid solutions, the formation of the following carbide phases was observed: Mn23C6, Mn5C2 and Mn7C3.

scholarly journals Hydration Study of Synthetic Yeelimite using LXRPD and SXRPD

2014 ◽  
Vol 70 (a1) ◽  
pp. C1096-C1096
Author(s):  
Ana Cuesta ◽  
Gema Alvarez Pinazo ◽  
Angeles De la Torre ◽  
Susana Sanfélix ◽  
Inmaculada Peral ◽  
...  
Keyword(s):  
Standard Method ◽  
Internal Standard ◽  
Free Water ◽  
Ex Situ ◽  
Quantitative Phase Analysis ◽  
Internal Standard Method ◽  
X Rays ◽  
X Ray ◽  
External Standard Method

XRPD is a powerful tool for material characterization in general, and for in-situ studies of chemical processes in particular. The use of an intense X-ray source, .i.e. synchrotron X-rays, coupled with fast X-ray detection permits time-resolved diffraction experiments allowing in-situ quantitative phase analysis during the early ages of cement hydration. Calcium sulfoaluminate, CSA, cements may have variable compositions, but all of them contain high amounts of ye'elimite, Ca4Al6O12SO4. Commercial CSA cements have special applications such as high strength developments at early-ages. Ye'elimite is very reactive and most of its hydration heat is released during the first eight hours of hydration . The aim of this work is to better understand the early age hydration of stoichiometric (orthorhombic) and doped (pseudo-cubic) ye'elimite samples. The parameters studied by SXRPD, LXRPD and calorimetry have been: polymorphism; water/ye'elimite ratio; and sulfate (gypsum and anhydrite) contents. This work has allowed establishing mechanisms and kinetics for hydration of ye'elimite samples by in-situ SXRPD with internal standard methodology. Moreover, pastes were also studied by ex-situ LXRPD with the external standard method, G-factor, at 2 and 7 days. Both strategies were able to quantify the amorphous contents, including free water. It is important to highlight that the results obtained at early ages, by the internal standard method, are in agreement with those obtained at later ages, G-method, showing the consistence and complementarity of both methodologies. The hydration of stoichiometric ye'elimite in the presence of gypsum is strongly hastened, when compared to the hydration process without gypsum. However, the presence of gypsum has a little effect in the hydration of doped ye'elimite. Moreover, anhydrite has also accelerated the hydration of stoichiometric ye'elimite, although its lower solubility has provoked the formation of an intermediate phase in the first hours.

Quantitation of Deltamethrin in Rat Liver and Muscle Homogenates Using Dispersive Solid-Phase Extraction with GC-NCI-MS

2016 ◽  
Vol 99 (3) ◽  
pp. 813-820 ◽  
Author(s):  
Darren R Gullick ◽  
James V Bruckner ◽  
Catherine A White ◽  
Chen Chen ◽  
Brian S Cummings ◽  
...  
Keyword(s):  
Rat Liver ◽  
Small Volume ◽  
Solid Phase ◽  
Internal Standard ◽  
Negative Ion ◽  
Tissue Homogenate ◽  
Mass Analyzer ◽  
Internal Standard Method ◽  
Rat Tissue ◽  
Better Than

Abstract An improved bioanalytical method to determine pyrethroids from small-volume (300 μL) rat liver and muscle homogenates was developed, validated, and applied to small-animal studies. The method used dispersive SPE (d-SPE) to clean the samples, and GC negative chemical ion MS (GC-NCI-MS) to analyze the samples. High-quality trace analysis of pyrethroids in biological samples was necessary to assess the health risk of environmentally encountered levels. Currently used highly sensitive methods to measure pyrethroids have focused on large-volume samples related to environmental exposure (water, soil, food products) or urine; however, there are no validated methods for quantifying this class of compounds in small-volume rat liver and muscle tissue homogenates. Individual rat tissue homogenate samples (300 μL) were prepared by protein precipitation using hexane-saturated acetonitrile. The samples were mixed on a vortex mixer and decanted into a d-SPE tube containing octadecylsilyl (C18) and primary secondary amine (PSA) sorbents and magnesium sulfate. The samples were centrifuged before evaporation to dryness. Pyrethroids were extracted and reconstituted from the residue using toluene in advance of injection into an Agilent Model 6890N gas chromatograph equipped with a Model 5973 quadrupole mass analyzer. Samples were ionized via electron capture in the negative ion mode using methane as a chemical ionization gas. Six qualifying ions were monitored using selected-ion monitoring for quantitation and verification of the analyte. Cis-permethrin was used as the internal standard. Method linearity was from 1 to 500 ng/mL for muscle and liver homogenates. The inter- and intraday precision and accuracy of the method were better than 20% at the lower LOQ and better than 15% over the remainder of the linear range. The method was used to elucidate tissue time-courses of deltamethrin (DLM) disposition following oral dosing of rats with 1 to 5 mg/kg in corn oil. DLM was monitored in rat tissue samples ≤24 h following dosing. Sample cleanup with d-SPE provided more selective chromatography than previous analytical methods.

In-Situ Transmission Electron Microscopy of the Solid-Phase Epitaxial Growth of GaAs: Sample Preparation and Artifact Characterization

1997 ◽  
Vol 480 ◽  
Author(s):  
K. B. Belay ◽  
M. C. Ridgway ◽  
D. J. Llewellyn
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Epitaxial Growth ◽  
Solid Phase ◽  
Ion Beam ◽  
Ex Situ ◽  
In Situ Tem ◽  
Transmission Electron

AbstractIn-situ transmission electron microscopy (TEM) has been used to characterize the solidphase epitaxial growth of amorphized GaAs at a temperature of 260°C. To maximize heat transfer from the heated holder to the sample and minimize electron-irradiation induced artifacts, non-conventional methodologies were utilized for the preparation of cross-sectional samples. GaAs (3xI) mm rectangular slabs were cut then glued face-to-face to a size of (6x3) mm stack by maintaining the TEM region at the center. This stack was subsequently polished to a thickness of ~ 200 ýtm. A 3 mm disc was then cut from it using a Gatan ultrasonic cutter. The disc was polished and dimpled on both sides to a thickness of ~15 mimT.h is was ion-beam milled at liquid nitrogen temperature to an electron-transparent layer. From a comparison of in-situ and ex-situ measurements of the recrystallization rate, the actual sample temperature during in-situ characterization was estimated to deviate by ≤ 20°C from that of the heated holder. The influence of electron-irradiated was found to be negligible by comparing the recrystallization rate and microstructure of irradiated and unirradiated regions of comparable thickness. Similarly, the influence of “thin-foil effect” was found to be negligible by comparing the recrystallization rate and microstructure of thick and thin regions, the former determined after the removal of the sample from the microscope and further ion-beam milling of tens of microns of material. In conclusion, the potential influence of artifacts during in-situ TEM can be eliminated by the appropriate choice of sample preparation procedures.

scholarly journals Determination of Bitertanol Residues in Strawberries by Liquid Chromatography with Fluorescence Detection and Confirmation by Gas Chromatography/Mass Spectrometry

1998 ◽  
Vol 81 (6) ◽  
pp. 1252-1256 ◽  
Author(s):  
Yoshie Yamazaki ◽  
Takahiro Ninomiya
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Liquid Chromatography ◽  
Ethyl Acetate ◽  
Fluorescence Detection ◽  
Solid Phase ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Internal Standard Method ◽  
Chromatography Mass Spectrometry

Abstract A simple and rapid method was developed for determining bitertanol residues in strawberries. Bitertanol was extracted from samples with ethyl acetate. Bitertanol acetate was added prior to extraction as a surrogate standard. The ethyl acetate extract was cleaned up by passing through tandem solid-phase extraction columns consisting of anion-exchange (SAX) and aminopropyl (NH2) bonded silica. The eluate was evaporated to dryness and reconstituted with methanol. Bitertanol residues were determined by liquid chromatography with fluorescence detection. Recoveries at 4 fortified levels (0.05,0.25,0.5, and 1.0 (µg/g), calculated by the internal standard method, ranged from 92.1 to 99.1 %, with coefficients of variation ranging from 0.3 to 4.0%. The detection limit was 0.01 µg/g. Of 25 commercial strawberry samples analyzed for bitertanol residues, 5 contained bitertanol residues at concentrations ranging from 0.02 to 0.51 µg/g. Positive samples were confirmed by gas chromatography/mass spectrometry with mass-selective detection (m/z 170 and 168).

In Situ Tem Studies of The Growth of Strained Si1-xGex By Solid Phase Epitaxy

1990 ◽  
Vol 202 ◽  
Author(s):  
D. C. Paine ◽  
D. J. Howard ◽  
N. D. Evans ◽  
D. W. Greve ◽  
M. Racanelli ◽  
...  
Keyword(s):  
Activation Energy ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Surface Region ◽  
In Situ Tem ◽  
Solid Phase Epitaxy ◽  
Near Surface ◽  
Strained Layer ◽  
Epitaxial Regrowth

ABSTRACTIn this paper we report on the epitaxial growth of strained thin film Si1-xGex on Si by solid phase epitaxy. For these solid phase epitaxy experiments, a 180-nm-thick strained-layer of Si1-xGex with xGe=11.6 at. % was epitaxially grown on <001> Si using chemical vapor deposition. The near surface region of the substrate, including the entire Si1-xGex film, was then amorphized to a depth of 380 nm using a two step process of 100 keV, followed by 200 keV, 29Si ion implantation. The epitaxial regrowth of the alloy was studied with in situ TEM heating techniques which enabled an evaluation of the activation energy for strained solid phase epitaxial regrowth. We report that the activation energy for Si1-xGex (x=l 1.6 at. %) strained-layer regrowth is 3.2 eV while that for unstrained regrowth of pure Si is 2.68 eV and that regrowth in the alloy is slower than in pure Si over the temperature range 490 to 600°C.

In situ TEM studies of the effect of misfit strain on the kinetics of sil-xgex solid phase epitaxy: temperature calibration & surface effects

1992 ◽  
Vol 50 (2) ◽  
pp. 1344-1345
Author(s):  
David C. Paine ◽  
David J. Howard ◽  
N.D. Evans
Keyword(s):  
Solid Phase ◽  
Misfit Strain ◽  
Alloy Layer ◽  
In Situ Tem ◽  
Transformation Rate ◽  
Solid Phase Epitaxy ◽  
Si Substrates ◽  
Kinetics Of ◽  
Annealing Experiments

While in situ TEM studies have proven useful for the direct observation of solid-state reaction mechanisms, such studies rarely provide quantitative kinetic data. This limitation is due to problems associated with the accurate measurement of local sample temperature, assessment of beam heating and damage, and minimization of thin-film effects. Sinclair et al. have proposed a technique for establishing the temperature of a sample during in situ TEM annealing experiments in which the wellcharacterized Si <001> solid phase epitaxy amorphous-crystalline (a/c) transformation rate is used to estimate the temperature in an adjacent (but not contiguous) region of the specimen. We have used this in situ technique to determine the activation energy for strained solid phase epitaxy of Sil-xGex (x=5.4, 11.6, and 17 at.%). The alloys were grown by CVD on <001> Si substrates to a thickness of approximately 200 nm. The entire alloy layer, and 180 nm of the underlying substrate, were amorphized with 100, followed by 200 keV 29Si implantation.

High-Fluence Implantation of Erbium into Silicon-Germanium Alloys: Structural and Thermal Properties

2000 ◽  
Vol 647 ◽  
Author(s):  
V. Touboltsev ◽  
J. Räisänen ◽  
E. Johnson ◽  
A. Johansen ◽  
L. Sarholt
Keyword(s):  
Silicon Germanium ◽  
Spontaneous Recovery ◽  
Solid Phase ◽  
Host Lattice ◽  
Host Matrix ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Recrystallization Front ◽  
Post Implantation

AbstractHigh-quality crystalline Si1-xGex (x=0.10 and 0.25) alloys were implanted with 70 keV Er+ ions at temperatures of 350°C and 550°C to a fluence of 1015 cm−2. In-situ Rutherford backscattering/channeling (RBS) analysis supplemented with transmission electron microscopy (TEM) showed that as-implanted alloys were in form of ternary solid solutions with a peak Er concentration of 1 at.% without any trace of Er-Si or Er-Ge precipitation.In the samples implanted at 350°C Er atoms were found to be distributed randomly in the amorphous host matrix. Post-implantation annealing at different temperatures up to 600° showed that the solid phase epitaxial regrowth of the damaged layers strongly depends on both the Ge concentration in the alloys and the temperature of annealing. Along with the recrystallization of the damaged matrix, annealing was observed to induce simultaneous removal of nearly all the implanted Er as the recrystallization front progresses towards the surface.In contrast, high temperature implantation at 550°C led to spontaneous recovery of the alloy crystallinity and incorporation of considerable fraction of implanted Er atoms on regular tetrahedral interstitial sites in the host lattice.

High Resolution In Situ TEM Studies of Silicide-Mediated Crystallization of Amorphous Silicon

1993 ◽  
Vol 321 ◽  
Author(s):  
C. Hayzelden ◽  
J. L. Batstone
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Solid Phase ◽  
In Situ Tem ◽  
Solid Phase Epitaxy ◽  
High Quality ◽  
Transmission Electron ◽  
Ledge Growth ◽  
Amorphous Si

ABSTRACTWe report in situ high resolution transmission electron microscopy studies of NiSi2-Medi-ated crystallization of Amorphous Si. Compared to conventional solid phase epitaxy of (111) Si, an enhancement of the growth rate by three orders of magnitude was observed and high quality twin-free needles of <111> Si were formed. Crystallization occurred via a ledge growth mechanism at the epitaxial Type A NiSi2/crystalline Si (111) interface. A Model for NiSi2-Mediated crystallization of Amorphous Si involving the passage of kinks along <110> ledges at the NiSi2/crystalline Si (111) interface is proposed.

Characterization of the Solid-Phase Epitaxial Growth of Amorphized Gaas with In-Situ Electron Microscopy

1996 ◽  
Vol 421 ◽  
Author(s):  
K. B. Belay ◽  
M. C. Ridgway ◽  
D. J. Llewellyn
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
Epitaxial Growth ◽  
Solid Phase ◽  
Ex Situ ◽  
In Situ Tem ◽  
Recrystallization Process ◽  
Time Resolved ◽  
Rich Material

AbstractThe influence of non-stoichiometry on the solid-phase epitaxial growth of amorphized GaAs has been studied with in-situ Transmission Electron Microscopy (TEM). Ion-implantation has been used to produce microscopic non-stoichiometry via Ga and As implants and macroscopic non-stoichiometry via Ga or As implants. It has been demonstrated that amorphous GaAs recrystallizes into a thin single-crystal layer and a thick heavily twinned layer. Video images of the recrystallization process have been quantified for the first time to study the velocity of the crystalline/amorphous (c/a)-interface as a function of depth and ion species. Regrowth rates of the single crystal and twinned layers as functions of non-stoichiometry have been calculated. The phase transformation is rapid in Ga-rich material. In-situ TEM results are consistent with conventional in-situ Time Resolved Reflectivity, ex-situ Rutherford Backscattering Spectroscopy and Channelling measurements and ex-situ TEM.

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