scholarly journals Amplification and spectral evidence of squeezing in the response of a strongly driven nanoresonator to a probe field

2021 ◽  
Vol 103 (1) ◽  
Author(s):  
J. S. Ochs ◽  
M. Seitner ◽  
M. I. Dykman ◽  
E. M. Weig
Keyword(s):  
Probe Field ◽  
Spectral Evidence

Preferential Sputtering of Ni3Al Single Crystals Studied Using Atom-Probe Field-Ion Microscopy and XPS

1981 ◽  
Vol 39 ◽  
pp. 16-17
Author(s):  
M.P. Thomas ◽  
A.R. Waugh ◽  
M.J. Southon ◽  
Brian Ralph
Keyword(s):  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Depth Profiling ◽  
Analytical Techniques ◽  
Atom Probe ◽  
Probe Field ◽  
Preferential Sputtering ◽  
Argon Ion Bombardment ◽  
Argon Ion

It is well known that ion-induced sputtering from numerous multicomponent targets results in marked changes in surface composition (1). Preferential removal of one component results in surface enrichment in the less easily removed species. In this investigation, a time-of-flight atom-probe field-ion microscope A.P. together with X-ray photoelectron spectroscopy XPS have been used to monitor alterations in surface composition of Ni3Al single crystals under argon ion bombardment. The A.P. has been chosen for this investigation because of its ability using field evaporation to depth profile through a sputtered surface without the need for further ion sputtering. Incident ion energy and ion dose have been selected to reflect conditions widely used in surface analytical techniques for cleaning and depth-profiling of samples, typically 3keV and 1018 - 1020 ion m-2.

High-resolution x-ray imaging of small copper-rich precipitates in steels

1988 ◽  
Vol 46 ◽  
pp. 528-529
Author(s):  
J. R. Michael ◽  
K. A. Taylor
Keyword(s):  
Electron Microscopy ◽  
Thermomechanical Processing ◽  
Atom Probe ◽  
Ferrite Matrix ◽  
Scanning Transmission Electron Microscope ◽  
Probe Field ◽  
X Ray ◽  
Subsequent Transformation ◽  
Transmission Electron ◽  
Scanning Transmission

Although copper is considered an incidental or trace element in many commercial steels, some grades contain up to 1-2 wt.% Cu for precipitation strengthening. Previous electron microscopy and atom-probe/field-ion microscopy (AP/FIM) studies indicate that the precipitation of copper from ferrite proceeds with the formation of Cu-rich bcc zones and the subsequent transformation of these zones to fcc copper particles. However, the similarity between the atomic scattering amplitudes for iron and copper and the small misfit between between Cu-rich particles and the ferrite matrix preclude the detection of small (<5 nm) Cu-rich particles by conventional transmission electron microscopy; such particles have been imaged directly only by FIM. Here results are presented whereby the Cu Kα x-ray signal was used in a dedicated scanning transmission electron microscope (STEM) to image small Cu-rich particles in a steel. The capability to detect these small particles is expected to be helpful in understanding the behavior of copper in steels during thermomechanical processing and heat treatment.

A Comparison of Tem and Apfim to the Interpretation of Modulated Microstructures

1985 ◽  
Vol 43 ◽  
pp. 70-71
Author(s):  
M.G. Burke ◽  
M.K. Miller
Keyword(s):  
Low Temperature ◽  
Microstructural Characterization ◽  
Superlattice Reflection ◽  
High Volume ◽  
Atom Probe ◽  
Dark Field ◽  
Miscibility Gap ◽  
Second Phase ◽  
Two Phase ◽  
Probe Field

Interpretation of fine-scale microstructures containing high volume fractions of second phase is complex. In particular, microstructures developed through decomposition within low temperature miscibility gaps may be extremely fine. This paper compares the morphological interpretations of such complex microstructures by the high-resolution techniques of TEM and atom probe field-ion microscopy (APFIM).The Fe-25 at% Be alloy selected for this study was aged within the low temperature miscibility gap to form a <100> aligned two-phase microstructure. This triaxially modulated microstructure is composed of an Fe-rich ferrite phase and a B2-ordered Be-enriched phase. The microstructural characterization through conventional bright-field TEM is inadequate because of the many contributions to image contrast. The ordering reaction which accompanies spinodal decomposition in this alloy permits simplification of the image by the use of the centered dark field technique to image just one phase. A CDF image formed with a B2 superlattice reflection is shown in fig. 1. In this CDF micrograph, the the B2-ordered Be-enriched phase appears as bright regions in the darkly-imaging ferrite. By examining the specimen in a [001] orientation, the <100> nature of the modulations is evident.

An Improved Method for the Preparation and TEM Examination of Sharp Pointed Tips used in APFIM and STM

1990 ◽  
Vol 48 (2) ◽  
pp. 102-103
Author(s):  
E.A. Fischione ◽  
P.E. Fischione ◽  
J.J. Haugh ◽  
M.G. Burke
Keyword(s):  
Atom Probe ◽  
Preparation Process ◽  
Improved Method ◽  
Ion Milling ◽  
Polishing Process ◽  
Probe Field ◽  
Scanning Tunnelling ◽  
Stm Tips ◽  
Tunnelling Microscopy ◽  
Ion Microscopy

A common requirement for both Atom Probe Field-Ion Microscopy (APFIM) and Scanning Tunnelling Microscopy (STM) is a sharp pointed tip for use as either the specimen (APFIM) or the probe (STM). Traditionally, tips have been prepared by either chemical or electropolishing techniques. Recently, ion-milling has been successfully employed in the production of APFIM tips [1]. Conventional electropolishing techniques are applicable to a wide variety of metals, but generally require careful manual adjustments during the polishing process and may also be time-consuming. In order to reduce the time and effort involved in the preparation process, a compact, self-contained polishing unit has been developed. This system is based upon the conventional two-stage electropolishing technique in which the specimen/tip blank is first locally thinned or “necked”, and subsequently electropolished until separation occurs.[2,3] The result of this process is the production of two APFIM or STM tips. A mechanized polishing unit that provides these functions while automatically maintaining alignment has been designed and developed.

Ordering in Ni4Mo by TEM and APFIM

1987 ◽  
Vol 45 ◽  
pp. 214-215
Author(s):  
E.A. Kenik ◽  
T.A. Zagula ◽  
M.K. Miller ◽  
J. Bentley
Keyword(s):  
Electron Irradiation ◽  
Low Temperatures ◽  
Short Range ◽  
Atom Probe ◽  
Range Order ◽  
Considerable Time ◽  
Probe Field ◽  
Disordered Phase ◽  
Transmission Electron ◽  
Diffraction Patterns

The state of long-range order (LRO) and short-range order (SRO) in Ni4Mo has been a topic of interest for a considerable time (see Brooks et al.). The SRO is often referred to as 1½0 order from the apparent position of the diffuse maxima in diffraction patterns, which differs from the positions of the LRO (D1a) structure. Various studies have shown that a fully disordered state cannot be retained by quenching, as the atomic arrangements responsible for the 1½0 maxima are present at temperatures above the critical ordering temperature for LRO. Over 20 studies have attempted to identify the atomic arrangements associated with this state of order. A variety of models have been proposed, but no consensus has been reached. It has also been shown that 1 MeV electron irradiation at low temperatures (∼100 K) can produce the disordered phase in Ni4Mo. Transmission electron microscopy (TEM), atom probe field ion microscopy (APFIM), and electron irradiation disordering have been applied in the current study to further the understanding of the ordering processes in Ni4Mo.

Fabrication and characterization - by High Resolution Electron Microscopy and atom probe microanalysis - of Co-based metallic multilayer films

1990 ◽  
Vol 48 (4) ◽  
pp. 772-773
Author(s):  
Amanda K. Petford-Long ◽  
A. Cerezo ◽  
M.G. Hetherington
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Atom Probe ◽  
Multilayer Films ◽  
Interface Roughness ◽  
Probe Field ◽  
Resolution Electron ◽  
Potential Applications ◽  
Field Ion Microscope

The fabrication of multilayer films (MLF) with layer thicknesses down to one monolayer has led to the development of materials with unique properties not found in bulk materials. The properties of interest depend critically on the structure and composition of the films, with the interfacial regions between the layers being of particular importance. There are a number of magnetic MLF systems based on Co, several of which have potential applications as perpendicular magnetic (e.g Co/Cr) or magneto-optic (e.g. Co/Pt) recording media. Of particular concern are the effects of parameters such as crystallographic texture and interface roughness, which are determined by the fabrication conditions, on magnetic properties and structure.In this study we have fabricated Co-based MLF by UHV thermal evaporation in the prechamber of an atom probe field-ion microscope (AP). The multilayers were deposited simultaneously onto cobalt field-ion specimens (for AP and position-sensitive atom probe (POSAP) microanalysis without exposure to atmosphere) and onto the flat (001) surface of oxidised silicon wafers (for subsequent study in cross-section using high-resolution electron microscopy (HREM) in a JEOL 4000EX. Deposi-tion was from W filaments loaded with material in the form of wire (Co, Fe, Ni, Pt and Au) or flakes (Cr). The base pressure in the chamber was around 8×10−8 torr during deposition with a typical deposition rate of 0.05 - 0.2nm/s.

8-Acyl-7-phenylbicyclo[2.2.2]-2,6-diones by rearrangement of 3-acyloxy-5-(2-phenylethenyl)-2-cyclohexen-1-ones. 1H and 13C NMR spectral evidence of their structure

1990 ◽  
Vol 55 (5) ◽  
pp. 1208-1215 ◽  
Author(s):  
Pavel Hrnčiar ◽  
Tibor Liptay ◽  
Ján Šraga
Keyword(s):  
Double Bond ◽  
Spectral Data ◽  
13C Nmr ◽  
1H And 13C Nmr ◽  
Spectral Evidence ◽  
C Nmr

3-Acyloxy-5-(2-phenylethenyl)-2-cyclohexen-1-ones II were prepared by O-acylation of 5-(2-phenylethenyl)-1,3-cycloxanedione (I). Treatment of II with AlCl3 resulted in rearrangement of the acyl group to the double bond of the phenylethenyl grouping followed by cyclization to 8-acyl-7-phenylbicyclo[2.2.2]octane-2,6-diones III. Their structure was evidenced by analysis of the 1H and 13C NMR spectral data.

scholarly journals Two New Compounds From the Heartwood of Dalbergia melanoxylon and Their Protective Effect on Hypoxia/Reoxygenation Injury in H9c2

2021 ◽  
Vol 16 (1) ◽  
pp. 1934578X2098777
Author(s):  
Yang Liu ◽  
Ni Zhang ◽  
Jun-wei He ◽  
Lan-ying Chen ◽  
Li Yang ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Lactate Dehydrogenase ◽  
Protective Effect ◽  
Superoxide Dismutase Activity ◽  
Spectral Evidence ◽  
Reoxygenation Injury ◽  
Dalbergia Melanoxylon ◽  
New Compounds ◽  
Hypoxia Reoxygenation

A new neoflavonoid, named as (7 R)-(-)-3′,5-dihydroxy-4′,2,4-trimethoxy-dalbergiquinol (1) and a new phenanthrenedione, named as 3′,7-dihydroxy-3,6- dimethoxy-9-phenyl-1,4-phenanthrenedione (2), together with 4 known compounds, 5- O-methyldalbergiphenol (3), 3′,7-dihydroxy-4′,3,6-trimethoxy-9-phenyl-1,4-phenanthrenedione (4), (+)-obtusafuran (5), and melanoxin (6) were isolated from the heartwood of Dalbergia melanoxylon. Their structures were elucidated on the basis of chemical and spectral evidence, as well as by comparison with literature data. Moreover, compound 1 showed a protective effect on hypoxia/reoxygenation injury in H9c2 at 10.0 μM by decreasing lactate dehydrogenase and malondialdehyde activity and enhancing superoxide dismutase activity.

EXPERIMENTAL INVESTIGATION OF LANGMUIR PROBES

1967 ◽  
Vol 45 (10) ◽  
pp. 3199-3209 ◽  
Author(s):  
R. M. Clements ◽  
H. M. Skarsgard
Keyword(s):  
Magnetic Field ◽  
Microwave Radiometer ◽  
Resonant Cavity ◽  
Boltzmann Distribution ◽  
Probable Error ◽  
Langmuir Probes ◽  
Noticeable Effect ◽  
Probe Field ◽  
Probe Radius ◽  
Weakly Ionized

Electron temperatures and densities measured in a weakly ionized helium afterglow with cylindrical double probes are compared with measurements obtained using a gated microwave radiometer and a microwave resonant cavity. The pressure was varied from 0.1 to 8.5 Torr. At low pressure, magnetic fields up to 0.11 T were applied. Independent of the values of the electron Larmor radii or particle mean free paths relative to the probe radius, the probes correctly measured the electron temperatures within an estimated random probable error of ±4% and a systematic error not exceeding ±4%. This demonstrates the validity, for the range of conditions studied, of a fundamental assumption of probe theory—that electrons in a retarding probe field are in a Maxwell–Boltzmann distribution at a temperature unaffected by the presence of the probe. Towards higher pressure the measurements show an increasing depression of the plasma density near the probe, associated with the diffusion to it. The applied magnetic field had no noticeable effect on the densities measured with the probes as compared with the cavity measurements.

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