HRTEM study of valleriite, a hydroxide-bearing copper sulfide

1990 ◽  
Vol 48 (4) ◽  
pp. 462-463
Author(s):  
S. Wang ◽  
P. R. Buseck
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Copper Sulfide ◽  
Carbonaceous Chondrite ◽  
Structural Data ◽  
Basic Structure ◽  
Long Period ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Wavy Structure

Valleriite is an unusual mineral, consisting of intergrowths of sulfide layers (corresponding in structure to the mineral smythite - Fe9S11) and hydroxide layers (corresponding to brucite - Mg(OH2)). It has a composition of approximately 1.526[Mg.68Al.32(OH)2].[Fe1.07Cu.93S2] and consists of two interpenetrating lattices, each of which retains its individual structural and diffraction characteristics parallel to the layering. The valleriite structure is related to that of tochilinite, an unusual iron-rich mineral that is of considerable interest for the origin of certain carbonaceous chondrite meteorites and to those of franckeite and cylindrite, two minerals that are of interest because of their unique morphological and crystallographic properties, e.g., the distinctive curved form of cylindrite and the perfect mica-like cleavage with unusual striations and the long-period wavy structure of franckeite.Our selected-area electron diffraction (SAED) patterns and high-resolution transmission electron microscope (HRTEM) images of valleriite provide new structural data. A basic structure and a new superstructure have been observed.

HRTEM Observation of Rod-Shape Precipitates in Al-Mg-Si-Ag Alloy Aged at 523 K

2007 ◽  
Vol 561-565 ◽  
pp. 243-246 ◽  
Author(s):  
Junya Nakamura ◽  
Kenji Matsuda ◽  
Yoshio Nakamura ◽  
Tatsuo Sato ◽  
Susumu Ikeno
Keyword(s):  
Crystal Structure ◽  
Electron Microscope ◽  
High Resolution ◽  
Electron Diffraction ◽  
Metastable Phase ◽  
X Ray ◽  
Β Phase ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Hrtem Observation

The purpose of this study is to identify the crystal structure of metastable phase in Ag added Al-Mg-Si alloy to compare the formation of β’-phases in Al-Mg-Si alloys without Ag, using images of high resolution transmission electron microscope (HRTEM), selected area electron diffraction (SAED) patterns and an energy dispersive X-ray spectroscopy (EDS). The result of SAED patterns and HRTEM images have been simulated and compared with images then SAED patterns obtained from actual precipitates. SAED patterns and HRTEM images obtained from metastable phase in the Ag added Al-Mg-Si alloy showed similar to those of β’-phase in Al-Mg-Si alloy without Ag and the lattice spacings changed because of the effect of Ag.

Comparative Studies of Magneto-Optical and Photocatalytic Properties of Magnetically Recyclable Spinel ZnFe2O4 Nanostructures by Combustion Methods

2019 ◽  
Vol 18 (02) ◽  
pp. 1850020 ◽  
Author(s):  
R. C. Sripriya ◽  
B. Vigneaswari ◽  
Victor Antony Raj
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Secondary Phase ◽  
Conventional Heating ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Phase Spinel ◽  
Improved Performance ◽  
The Comparative Study

Spinel ZnFe2O4 nanoparticles (NPs) were successfully synthesized by a simple microwave irradiation method (MIM) using glycine as the fuel. For the comparative study purpose, it was also prepared by conventional heating (CHM) method. Powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), high resolution scanning electron microscope (HR-SEM), high resolution transmission electron microscope (HR-TEM), energy dispersive X-ray (EDX) spectra, selected area electron diffraction (SAED) analysis showed that the samples were pure phase spinel ZnFe2O4 nanoparticles-like morphology without any other secondary phase impurity. UV-Visible diffuse reflectance spectra (DRS) and room temperature photoluminescence (PL) spectra were confirmed the optical bandgap ([Formula: see text] and defects state of the samples. The calculated [Formula: see text] values of the samples are 1.91[Formula: see text]eV and 2.08[Formula: see text]eV for ZnFe2O4-MIM and ZnFe2O4-CHM, respectively. Vibrating sample magnetometer (VSM) analysis show the Ms value is 37.66[Formula: see text]emu/g for ZnFe2O4-MIM, which is higher than ZnFe2O4-CHM (24.23 emu/g) sample, which confirm both the products showed superparamagnetic behavior. ZnFe2O4-MIM was found to have higher surface area than ZnFe2O4-CHM, which in turn leads to the improved performance toward the photocatalytic degradation (PCD) of 4-chlorophenol (4-CP) and it was found that the sample ZnFe2O4-MIM show higher PCD efficiency (91.43%) than ZnFe2O4-CHM (84.65%), also the samples show high activity, good reusability, remarkable stability and environmentally friendly materials for industrial and technological applications.

The Effect of Ag-Addition on Crystal Structure of β'-Phase in Al-Mg-Si Alloy

2006 ◽  
Vol 519-521 ◽  
pp. 511-514 ◽  
Author(s):  
Junya Nakamura ◽  
Kenji Matsuda ◽  
Yoshio Nakamura ◽  
Tatsuo Sato ◽  
Susumu Ikeno
Keyword(s):  
Crystal Structure ◽  
Electron Microscope ◽  
High Resolution ◽  
Metastable Phase ◽  
Ag Addition ◽  
X Ray ◽  
Β Phase ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Diffraction Patterns

The purpose of this study is identity the crystal structure of metastable phase in Ag added Al-Mg-Si alloy by comparing the β’-phases in Al-Mg-Si alloy without Ag, using images of high resolution transmission electron microscope (HRTEM), selected area electron diffraction patterns (SADPs) and an energy dispersive X-ray spectroscopy (EDS). The result of SADPs and HRTEM images have been simulated and compared with images and SADPs obtained from actual precipitates. SADPs and HRTEM images obtained from metastable phase in the Ag added Al-Mg-Si alloy showed similar to those of β’-phase in Al-Mg-Si alloy without Ag and had different lattice spacings because of the effect of Ag.

Crystal Structure of the β'-Phase in Al-Mg-Si-Ag Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 837-841 ◽  
Author(s):  
Kenji Matsuda ◽  
Junya Nakamura ◽  
Yoshio Nakamura ◽  
Tatsuo Sato ◽  
Susumu Ikeno
Keyword(s):  
Crystal Structure ◽  
Electron Microscope ◽  
High Resolution ◽  
Metastable Phase ◽  
Careful Analysis ◽  
X Ray ◽  
Β Phase ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Diffraction Patterns

The crystal structure of metastable phase in Ag added Al-Mg-Si alloy was investigated by comparing the β’-phases in Al-Mg-Si alloy without Ag, using images of high resolution transmission electron microscope (HRTEM), selected area electron diffraction patterns (SADPs) and an energy dispersive X-ray spectroscopy (EDS). SADPs and HRTEM images obtained from metastable phase in the Ag added Al-Mg-Si alloy showed similar to those of β’-phase in Al-Mg-Si alloy without Ag and had different lattice spacings because of the effect of Ag. According to our careful analysis on obtained HRTEM images and SADPs, it includes more complicated crystal lattice of distorted hexagons.

Nano-Structural Alteration of Pyrophyllite by Grinding Revealed by X-Ray Diffraction and High-Resolution Transmission Electron Microscopy

2016 ◽  
Vol 40 ◽  
pp. 72-78 ◽  
Author(s):  
Jia Wei Sheng ◽  
Li Ping Zhang ◽  
Jun Yan ◽  
Qing Sun ◽  
Jian Zhang
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Ball Mill ◽  
Structural Alteration ◽  
X Ray Diffraction ◽  
Mechanical Destruction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Scanning Electron

The mechanical destruction of the pyrophyllite structure and final ground products upon grinding with a laboratory planetary ball mill were investigated using high-resolution transmission electron microscope (HRTEM) coupled with selected area electron diffraction (SAED), field emission scanning electron microscope (SEM) and X-ray diffraction (XRD). Grinding produced a profound structural alteration, resulting in increasing amorphization. Increasing the intensity of grinding resulted in acceleration of the mechanically induced amorphization of the pyrophyllite structure. The pyrophyllite phase was transformed into its anhydride phase during the process of the prolonged grinding. Increasing the grinding intensity resulted in faster destruction of the pyrophyllite structure. The plate-like microcrystal exhibited the 2M-pyrophyllite crystal structure. The pyrophyllite anhydride phase was existed after grinding.

The High Resolution Scanning Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 316-317
Author(s):  
A. V. Crewe
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
High Vacuum ◽  
Scanning Transmission Electron Microscope ◽  
Ultra High Vacuum ◽  
Resolving Power ◽  
Imaging Characteristics ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Moment

The high resolution STEM is now a fact of life. I think that we have, in the last few years, demonstrated that this instrument is capable of the same resolving power as a CEM but is sufficiently different in its imaging characteristics to offer some real advantages.It seems possible to prove in a quite general way that only a field emission source can give adequate intensity for the highest resolution^ and at the moment this means operating at ultra high vacuum levels. Our experience, however, is that neither the source nor the vacuum are difficult to manage and indeed are simpler than many other systems and substantially trouble-free.

A New High Resolution Transmission Electron Microscope with Second-Zone Objective Lens

1969 ◽  
Vol 27 ◽  
pp. 176-177 ◽  
Author(s):  
H. Tochigi ◽  
H. Uchida ◽  
S. Shirai ◽  
K. Akashi ◽  
D. J. Evins ◽  
...  
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Electron Microscope ◽  
Objective Lens ◽  
High Excitation ◽  
Transmission Electron ◽  
New Instrument

A New High Excitation Objective Lens (Second-Zone Objective Lens) was discussed at Twenty-Sixth Annual EMSA Meeting. A new commercially available Transmission Electron Microscope incorporating this new lens has been completed.Major advantages of the new instrument allow an extremely small beam to be produced on the specimen plane which minimizes specimen beam damages, reduces contamination and drift.

To What Extent are Inelastically Scattered Electrons Useful in the Stem?

1973 ◽  
Vol 31 ◽  
pp. 286-287 ◽  
Author(s):  
H. Rose
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Electron Correlation ◽  
Quantum Noise ◽  
Collection Efficiency ◽  
Scanning Transmission Electron Microscope ◽  
Electron Cloud ◽  
Scanning Time ◽  
Transmission Electron ◽  
Scanning Transmission

The scanning transmission electron microscope offers the possibility of utilizing inelastically scattered electrons. Use of these electrons in addition to the elastically scattered electrons should reduce the scanning time (dose) Which is necessary to keep the quantum noise below a certain level. Hence it should lower the radiation damage. For high resolution, Where the collection efficiency of elastically scattered electrons is small, the use of Inelastically scattered electrons should become more and more favorable because they can all be detected by means of a spectrometer. Unfortunately, the Inelastic scattering Is a non-localized interaction due to the electron-electron correlation, occurring predominantly at the circumference of the atomic electron cloud.

A High Resolution Study of Alumina Supported Iridium Catalysts

1980 ◽  
Vol 38 ◽  
pp. 202-203
Author(s):  
C. Stoeckert ◽  
B. Etherton ◽  
M. Beer ◽  
J. Gryder
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Metal Particles ◽  
Optical Transfer Function ◽  
Particle Sizes ◽  
Iridium Catalysts ◽  
Transmission Electron ◽  
Optical Transfer ◽  
Conventional Transmission Electron Microscope ◽  
Resolution Study

The interpretation of the activity of catalysts requires information about the sizes of the metal particles, since this has implications for the number of surface atoms available for reaction. To determine the particle dimensions we used a high resolution STEM1. Such an instrument with its simple optical transfer function is far more suitable than a conventional transmission electron microscope for the establishment of particle sizes. We report here our study on the size and number distribution of Ir particles supported on Al2O3 and also examine simple geometric models for the shape of Ir particles.

A Working Method for Adapting the (SEM) Scanning Electron Microscope to Produce (STEM) Scanning Transmission Electron Microscope Images

2002 ◽  
Author(s):  
Edward Coyne
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Integrated Circuits ◽  
Theoretical Idea ◽  
Cross Sectional ◽  
Additional Advantage ◽  
Transmission Electron ◽  
Resolution Element ◽  
Scanning Electron

Abstract This paper describes the problems encountered and solutions found to the practical objective of developing an imaging technique that would produce a more detailed analysis of IC material structures then a scanning electron microscope. To find a solution to this objective the theoretical idea of converting a standard SEM to produce a STEM image was developed. This solution would enable high magnification, material contrasting, detailed cross sectional analysis of integrated circuits with an ordinary SEM. This would provide a practical and cost effective alternative to Transmission Electron Microscopy (TEM), where the higher TEM accelerating voltages would ultimately yield a more detailed cross sectional image. An additional advantage, developed subsequent to STEM imaging was the use of EDX analysis to perform high-resolution element identification of IC cross sections. High-resolution element identification when used in conjunction with high-resolution STEM images provides an analysis technique that exceeds the capabilities of conventional SEM imaging.

Sign in / Sign up

Export Citation Format

Share Document