Field Emission and Electron Microscopy

2000 ◽  
Vol 6 (4) ◽  
pp. 380-387 ◽  
Author(s):  
Christopher John Edgcombe ◽  
Ugo Valdrè
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Optical Bench ◽  
Carbon Contamination ◽  
Electron Sources ◽  
Basic Properties ◽  
Scanning Electron

AbstractAn overview and new results are presented of the investigations carried out in the last 5 years on nano-sized tips by means of electron microscopy, an electron optical bench, and computation. Tungsten and, in particular, carbon nano-tips prepared by carbon contamination in a scanning electron microscope, were studied for applications as field-emission electron sources. Several features of their use are described and the results concerning the determination of some of their basic properties are reported.

Field Emission and Electron Microscopy

2000 ◽  
Vol 6 (4) ◽  
pp. 380-387
Author(s):  
Christopher John Edgcombe ◽  
Ugo Valdrè
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Optical Bench ◽  
Carbon Contamination ◽  
Electron Sources ◽  
Basic Properties ◽  
Scanning Electron

Abstract An overview and new results are presented of the investigations carried out in the last 5 years on nano-sized tips by means of electron microscopy, an electron optical bench, and computation. Tungsten and, in particular, carbon nano-tips prepared by carbon contamination in a scanning electron microscope, were studied for applications as field-emission electron sources. Several features of their use are described and the results concerning the determination of some of their basic properties are reported.

Investigation of the Adhesion Layer Formed on Brass Using Field Emission-Scanning Electron Microscope

2005 ◽  
Vol 78 (5) ◽  
pp. 844-854 ◽  
Author(s):  
Jong Myoung Kim
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Metal Sulfides ◽  
Adhesion Layer ◽  
Pull Out ◽  
Aging Test ◽  
Scanning Electron

Abstract Change in the morphological features of the adhesion layer formed on brass was observed with Field Emission-Scanning Electron Microscopy (FE-SEM). The effect of the key compounding ingredients on the morphology of the adhesion layer was studied. Morphology of the various metal sulfides of cobalt, zinc, copper, bronze and brass was also observed with FE-SEM. Fracture mode appeared during the pull-out test was categorized and was correlated with the adhesion strength. The damage on the adhesion layer after humidity aging test was examined by FE-SEM.

Examination of Frozen, Hydrated Mites Using Low Temperature Field Emission Scanning Electron Microscopy

2000 ◽  
Vol 6 (S2) ◽  
pp. 874-875 ◽  
Author(s):  
Ronald Ochoa ◽  
Eric F. Erbe ◽  
Jeffery S. Pettis ◽  
William P. Wergin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Temperature Field ◽  
Electron Microscope ◽  
Low Temperature ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Viral Diseases ◽  
Depth Of Field ◽  
Scanning Electron

Mites, the second largest arthropod group after insects, occupy every conceivable terrestrial and aquatic habitat in our environment. They feed on plants, infest food products such as meat, cheese and grains, parasitize invertebrates and vertebrates, and transmit fungal, bacterial, rickettsial and viral diseases. Estimates indicate that as many as 1,000,000 species of mites may exist; however, partly because of their microscopic size, only about 40,000 species have been described and classified. During the last 30 years, researchers have increasingly utilized the greater magnification and depth of field available in a conventional scanning electron microscope (SEM) to supplement descriptions of mites that were historically based on light microscopic observations. In addition, this technique provided a better understanding of the relative positions and functionality of organs and improved attempts to elucidate their biology. However, before mites can be imaged with a conventional SEM, they are typically chemically fixed, dehydrated and/or thoroughly dried.

Field Emission SEM Equipped With Noise Compensator

1973 ◽  
Vol 31 ◽  
pp. 302-303
Author(s):  
S. Saito ◽  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Contrast ◽  
Probe Current ◽  
High Resolution Images ◽  
Scanning Electron

Field emission scanning electron microscope (FESEM) features extremely high resolution images, and offers many valuable information. But, for a specimen which gives low contrast images, lateral stripes appear in images. These stripes are resulted from signal fluctuations caused by probe current noises. In order to obtain good images without stripes, the fluctuations should be less than 1%, especially for low contrast images. For this purpose, the authors realized a noise compensator, and applied this to the FESEM.Fig. 1 shows an outline of FESEM equipped with a noise compensator. Two apertures are provided gust under the field emission gun.

High Resolution Scanning Electron Microscopy

1991 ◽  
Vol 49 ◽  
pp. 478-479
Author(s):  
David Joy ◽  
James Pawley
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Beam ◽  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Electron Probe ◽  
Impact Point ◽  
Interaction Volume ◽  
Scanning Electron

The scanning electron microscope (SEM) builds up an image by sampling contiguous sub-volumes near the surface of the specimen. A fine electron beam selectively excites each sub-volume and then the intensity of some resulting signal is measured. The spatial resolution of images made using such a process is limited by at least three factors. Two of these determine the size of the interaction volume: the size of the electron probe and the extent to which detectable signal is excited from locations remote from the beam impact point. A third limitation emerges from the fact that the probing beam is composed of a finite number of discrete particles and therefore that the accuracy with which any detectable signal can be measured is limited by Poisson statistics applied to this number (or to the number of events actually detected if this is smaller).

Comparison of freeze-fractured yeast replicas using conventional TEM and low-voltage field-emission SEM

1989 ◽  
Vol 47 ◽  
pp. 74-75
Author(s):  
William P. Wergin ◽  
Eric F. Erbe ◽  
Terrence W. Reilly
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Voltage ◽  
Objective Lens ◽  
Specimen Preparation ◽  
Lens System ◽  
Air Drying ◽  
Preparation Techniques ◽  
Scanning Electron

Although the first commercial scanning electron microscope (SEM) was introduced in 1965, the limited resolution and the lack of preparation techniques initially confined biological observations to relatively low magnification images showing anatomical surface features of samples that withstood the artifacts associated with air drying. As the design of instrumentation improved and the techniques for specimen preparation developed, the SEM allowed biologists to gain additional insights not only on the external features of samples but on the internal structure of tissues as well. By 1985, the resolution of the conventional SEM had reached 3 - 5 nm; however most biological samples still required a conductive coating of 20 - 30 nm that prevented investigators from approaching the level of information that was available with various TEM techniques. Recently, a new SEM design combined a condenser-objective lens system with a field emission electron source.

SCANNING ELECTRON MICROSCOPE: POSSIBILITIES FOR STUDYING KIDNEY DISEASES

2020 ◽  
pp. 176-182
Author(s):  
Mamaeva S.N. ◽  
Vinokurov R.R. ◽  
Munkhalova Ya.A. ◽  
Dyakonova D.P. ◽  
Platonova V.A. ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Filtration Rate ◽  
Kidney Diseases ◽  
First Time ◽  
Scanning Electron

Currently, due to the intensive development of high-tech science-intensive medical and research devices, more and more attention is paid to the development of diagnostics of rare and difficult to diagnose diseases. It is known that among numerous nephropathies, hematuria may be the only symptom of kidney and urinary tract diseases, which complicates their diagnosis and treatment. In order to develop new approaches for the diagnosis of nephropathies, the authors have been studying the morphology of red blood cells in the blood and urine of children and adults using a scanning electron microscope for several years. The paper presents the results of studies of children with various kidney diseases, including IgA-nephropathy, and chronic glomerulonephritis. Scanning electron microscopy was used for the first time to detect nanoparticles on the surface of red blood cells, the size of which is comparable to the size of viruses, which became the basis for one of the authors ' assumptions, namely, the possible transport of certain types of viruses by red blood cells. Thus, some kidney diseases could be considered virus-associated. This paper presents for the first time the results of determining the glomerular filtration rate of both kidneys separately in the study of separate kidney function and of the study of urine smears obtained during catheterization of the ureters in patients with hydronephrosis of one of the kidneys by scanning electron microscopy. As in previous studies, nanoparticles were found on the surface of red blood cells, which leads to the conclusion about the possible viral nature of the disease of the considered patient. In addition, smear images obtained using a microscope showed a significant difference in the elements of the right and left kidneys urine, which did not contradict the data on the study of glomerular filtration rate. According to the authors, the capabilities of the scanning electron microscope can be applied in fundamental research of kidney diseases at the cellular and molecular levels, forming new ideas about their origin, as well as on the basis of which new methods of non-invasive diagnostics can be built.

The External Morphology of the Eggs of Culex (Culex) saltanensis (Diptera: Culicidae) Under Scanning Electron Microscopy

2020 ◽  
Author(s):  
J R Santos-Mallet ◽  
T D Balthazar ◽  
A A Oliveira ◽  
W A Marques ◽  
A Q Bastos ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Optical Microscopy ◽  
Osmium Tetroxide ◽  
Neotropical Region ◽  
External Morphology ◽  
Metal Supports ◽  
Scanning Electron

Abstract The aim of the present study was to describe the morphology of the eggs of Culex (Culex) saltanensis Dyar that occurs in the Neotropical region. Eggs of the Cx. (Cux.) saltanensis were collected at the Mata Atlântica FIOCRUZ campus, fixed in 1% osmium tetroxide, prepared for mounting on metal supports, observed under a scanning electron microscope, and described morphologically. The eggs had a coniform shape with a length of approximately 0.5 mm (505–510 µm) and a width in the median portion of 117 µm (113–123 µm). Upper portion is lined with tubers of irregular shape and varying sizes (0.64–1.31 µm), located on a cross-linked matrix forming bands observed under optical microscopy. The micropyle is encased in a necklace of approximately 6.6-µm plates arranged in a flower-like shape. Comparing Cx. (Cux.) saltanensis eggs with several species of different genera, important divergent characteristics can be observed. However, this study points to the need for new descriptions of eggs of species belonging to the same subgenus in order to analyze if there will be differences between them. Culex (Cux.) saltanensis eggs have particular characteristics not observed in eggs of other Culicidae genera.

Sign in / Sign up

Export Citation Format

Share Document