A method to study the effect of chemical dissolution on the morphology of soil clay

Clay Minerals ◽  
1997 ◽  
Vol 32 (2) ◽  
pp. 315-318
Author(s):  
M. Hagiwara
Keyword(s):  
Electron Microscopy ◽  
Infrared Spectroscopy ◽  
Inorganic Material ◽  
Morphological Changes ◽  
The Other ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Chemical Dissolution ◽  
Soil Clays ◽  
Soil Clay

Soil clays contain a relatively large amount of disordered inorganic material. Chemical dissolution has been used for the removal of this material (Jackson, 1956; Hashimoto & Jackson, 1960; Follett et al, 1965 a,b; Wada & Greenland, 1970). On the other hand, Farmer et al. (1977) claimed that dissolution of allophane and imogolite with hot 5% Na2CO3 for periods of 2-100 h led to new phases which could be distinguished from the starting material by infrared spectroscopy. It is clear, therefore, that chemical dissolution can alter soil clays. This note suggests an electron microscopy specimen preparation technique to study the morphological changes. Collodion films containing densely arranged minute hollows are used for specimen supports.

The ionic strength dependence of chromatin folding

1978 ◽  
Vol 36 (2) ◽  
pp. 220-221
Author(s):  
F. Thoma ◽  
TH. Koller
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Ionic Strength ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Carbon Supports ◽  
Ionic Strength Dependence ◽  
Chromatin Folding ◽  
Strength Dependence ◽  
Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

Transmission Electron Microscopy (TEM) Specimen Preparation Technique using Focused Ion Beam (FIB): Application to Material Characterization of Chemical Vapor Deposition of Tungsten (W) and Tungsten Silicides (WSix)

1997 ◽  
Author(s):  
K. Doong ◽  
J.-M. Fu ◽  
Y.-C. Huang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Transmission Electron

Abstract The specimen preparation technique using focused ion beam (FIB) to generate cross-sectional transmission electron microscopy (XTEM) samples of chemical vapor deposition (CVD) of Tungsten-plug (W-plug) and Tungsten Silicides (WSix) was studied. Using the combination method including two axes tilting[l], gas enhanced focused ion beam milling[2] and sacrificial metal coating on both sides of electron transmission membrane[3], it was possible to prepare a sample with minimal thickness (less than 1000 A) to get high spatial resolution in TEM observation. Based on this novel thinning technique, some applications such as XTEM observation of W-plug with different aspect ratio (I - 6), and the grain structure of CVD W-plug and CVD WSix were done. Also the problems and artifacts of XTEM sample preparation of high Z-factor material such as CVD W-plug and CVD WSix were given and the ways to avoid or minimize them were suggested.

A Technique for Preparing “Two in One” Cross-Sectional TEM Specimens

1990 ◽  
Vol 199 ◽  
Author(s):  
Guang-Hwa M. Ma ◽  
Sopa Chevacharoenkul
Keyword(s):  
Sample Preparation ◽  
The Other ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Preparation Time ◽  
Cross Sectional ◽  
Sample Preparation Technique ◽  
Two Samples ◽  
Junction Formation ◽  
Suitable Marker

ABSTRACTA modified “two-in-one” cross-sectional TEM sample preparation technique is described. By coating a thin layer of “marker” to distinguish one sample from the other, two samples could be simultaneously prepared in one TEM cross-sectional specimen. Therefore, the specimen preparation time is reduced by nearly one half. The coating can be done in an existing ion-mill. Criteria for choosing a suitable marker as well as tips on getting good quality specimens are described. An example of applying this technique to a processing-microstructure study of an ultra-shallow junction formation in silicon is demonstrated.

High Voltage Electron Microscopy of Integrated Circuit Devices

1972 ◽  
Vol 30 ◽  
pp. 486-487
Author(s):  
P. J. Smith ◽  
H. A. Troutman ◽  
R. K. Raheja
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Integrated Circuit ◽  
Complete Characterization ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Transmission Microscopy ◽  
Entire Area ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron

One-MEV transmission electron microscopy has been used to examine the complete structure of individual integrated circuit devices. The use of high voltage microscopy provided sufficient penetration to examine the entire emitter and base regions, while a new specimen preparation technique ensured that the device was uniformly thinned.As previously reported, a TEM specimen preparation technique has been developed which uses the structure of the device itself to form the thinned sample. This technique has been used to prepare samples which are uniformly thin over the entire area of the device. Thus the complete characterization of the defect structure within the device is possible; this is necessary if a direct relationship between structure and electrical properties is to be made. Samples approximately 3 μ m thick were prepared so that the complete emitter and base regions and part of the collector could be examined by high voltage transmission microscopy. The emitter-base and collector-base junctions were 1.7 μ m and 2.1 μ m deep respectively. The base dopant was boron and the emitter dopant was phosphorous.

scholarly journals Encapsulation of Fullerenes: A Versatile Approach for the Confinement and Release of Materials Within Open-Ended Multiwalled Carbon Nanotubes

2021 ◽  
Vol 9 ◽  
Author(s):  
Stefania Sandoval ◽  
Gerard Tobias
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Transmission Electron Microscopy ◽  
Multiwalled Carbon Nanotubes ◽  
Inorganic Material ◽  
Single Step ◽  
The Other ◽  
Multiwalled Carbon ◽  
Mild Conditions ◽  
Transmission Electron

We have employed fullerenes as versatile agents to “cork” the open tips of multiwalled carbon nanotubes (MWCNTs), and as promoting species for the release of the inorganic material filled within the nanotubes’ cavities. High Z element compounds, namely, PbI2, ZnI2, and CeI3, were chosen to easily determine the presence of the filler inside the hosting nanotubes by transmission electron microscopy (TEM). Fullerenes can isolate inorganic nanostructures confined within the hollow cavities of MWCNTs, which allows the removal of the external material remnant after the filling. Otherwise, taking advantage of the affinity of fullerenes with selected solvents, we have confirmed the ability of the C60 molecules to promote the displacement of the inorganic guest from the host. We propose two different strategies to trigger the release, employing vapor and liquid phase treatments. The first protocol involves annealing filled MWCNTs in presence of fullerenes (to obtain C60PbI2@MWCNTs) and the subsequent washing of the sample in ethanol under mild conditions. On the other hand, the simultaneous introduction of the C60 molecules and the liberation of the guest are produced by a single step wet procedure; the latter being potentially useful when materials that are not stable at high temperatures are employed for filling.

Orientation of the purple membrane using a new specimen preparation technique

1978 ◽  
Vol 36 (2) ◽  
pp. 282-283
Author(s):  
S.B. Hayward
Keyword(s):  
Molecular Structure ◽  
Purple Membrane ◽  
The Other ◽  
Specimen Preparation ◽  
Halobacterium Halobium ◽  
Preparation Technique ◽  
Selected Area Electron Diffraction ◽  
Diffraction Patterns ◽  
Cytoplasmic Side ◽  
Purple Membranes

It is known that the purple membrane of Halobacterium halobium is asymmetric with respect to its function as a proton pump. It has also been shown that the structure of the membrane is asymmetric, both with respect to its profile, and with respect to its handedness when viewed from one side or the other. Recently, Henderson has determined which side of the molecular structure corresponds to the cytoplasmic side of the membrane. This paper reports the application of a new method of frozen-hydrated specimen preparation to this same question. This specimen preparation technique has made possible the recording of selected-area electron diffraction patterns from membranes that have been adsorbed to polylysine-coated grids. At pH 7.4 purple membranes have been shown to adsorb preferentially with the cytoplasmic side toward the polylysine. This orientation has been shown to reverse 2/3 of the time when membranes have been titrated to pH4 before adsorption.

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