An electron microscope study of evaporating gold particles: the Kelvin equation for liquid gold and the lowering of the melting point of solid gold particles

An electron microscope has been used to observe the evaporation of small ( < 50 nm radius) gold particles resting on heated carbon substrates in a vacuum of 2.7 x 10 -4 Pa. Evaporation curves for liquid gold particles are found to agree with the predictions of Kelvin’s theory which relates vapour pressure to surface curvature and, at low evaporation rates, the evaporation curves for solid gold particles also have the expected monotonic form. However, with solid gold particles evaporating in the temperature range 1160 to 1330 K, evaporation curves have been obtained showing a characteristic ‘kinked’ nature; that is, on each curve obtained, there appears to be two sections consistent with two different rates of evaporation. These non-monotonic curves have been interpreted as being caused by the melting of the slowly evaporating solid gold particles into liquid—the difference in evaporation coefficient between solid and liquid gold giving the observed sudden change in evaporation rate. From these results a plot of particle radius against melting temperature has been obtained.

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An electron microscope study of evaporating small particles: the Kelvin equation for liquid lead and the mean surface energy of solid silver

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1970.0157 ◽

1970 ◽

Vol 318 (1535) ◽

pp. 507-522 ◽

Cited By ~ 47

Keyword(s):

Electron Microscope ◽

Surface Energy ◽

Microscope Study ◽

Electron Microscope Study ◽

Liquid Lead ◽

Small Particles ◽

Kelvin Equation ◽

A Value ◽

Carbon Substrates ◽

The Mean

An electron microscope study of evaporating liquid lead particles, formed on carbon substrates by nucleation from the vapour, has led to a confirmation of the Kelvin equation which relates equilibrium vapour pressure to surface curvature. Observations of the same kind made on particles of evaporating solid silver have produced evaporation curves similar to those for lead. Interpretation of these curves in terms of the Kelvin equation for solids has yielded a value for the mean surface energy of silver of 1.20 ± 0.06 J m -2 (1200 ± 60 erg cm -2 ) at 1005 ± 25 K.

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Ultrastructure of Plant Leaf Tissue Infected with Mite-Borne Viral-Like Pathogens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100067881 ◽

1970 ◽

Vol 28 ◽

pp. 178-179 ◽

Cited By ~ 2

Author(s):

O. E. Bradfute ◽

R. E. Whitmoyer ◽

L. R. Nault

Keyword(s):

Triticum Aestivum ◽

Zea Mays ◽

Electron Microscope ◽

Hordeum Vulgare ◽

Microscope Study ◽

Electron Microscope Study ◽

Leaf Tissue ◽

Leaf Ultrastructure ◽

Double Membrane ◽

Aceria Tulipae

A pathogen transmitted by the eriophyid mite, Aceria tulipae, infects a number of Gramineae producing symptoms similar to wheat spot mosaic virus (1). An electron microscope study of leaf ultrastructure from systemically infected Zea mays, Hordeum vulgare, and Triticum aestivum showed the presence of ovoid, double membrane bodies (0.1 - 0.2 microns) in the cytoplasm of parenchyma, phloem and epidermis cells (Fig. 1 ).

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Electron microscope study of the microgranules in human vaginal epithelium

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100083710 ◽

1978 ◽

Vol 36 (2) ◽

pp. 568-569

Author(s):

A. Campos ◽

J. Vilches ◽

J. Gomez

Keyword(s):

Electron Microscope ◽

Microscope Study ◽

Intercellular Space ◽

Electron Microscope Study ◽

Vaginal Epithelium ◽

Vaginal Mucosa ◽

Secretory Phase ◽

Cervical Epithelium ◽

Keratinized Epithelium ◽

Fertile Women

Microgranules have been described with different names in keratinized and in nonkeratinized epithelium. In keratinized epithelium it seems clear that the microgranules are lamellated bodies bounded by a membrane which empty their contents into the intercellular space. Their existence in nonkeratinized epithelium is more debatable. Until now the so-called microgranules have been described in nonkeratinized bucal, lingual and cervical epithelium. In the present work we describe the morphology and nature of such structures in human vaginal epithelium.Biopsies from the midlevel of the vaginal mucosa were taken from voluntary fertile women. The specimens were divided into three groups with four vaginal specimens. The first group was obtained in the folicular phase; those of the second in the postovulatory phase and, finally, the last group corresponded to the secretory phase.

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A Scanning Electron Microscope Study of Isolated Guard Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010007271x ◽

1973 ◽

Vol 31 ◽

pp. 454-455 ◽

Cited By ~ 1

Author(s):

P. Dayanandan ◽

P. B. Kaufman

Keyword(s):

Electron Microscope ◽

Electron Microscope Study ◽

Three Dimensional ◽

Guard Cells ◽

Scanning Electron Microscope Study ◽

Psilotum Nudum ◽

Subsidiary Cells ◽

Welwitschia Mirabilis ◽

Cycas Revoluta ◽

Scanning Electron

A three dimensional appreciation of the guard cell morphology coupled with ultrastjuctural studies should lead to a better understanding of their still obscure dynamics of movement. We have found the SEM of great value not only in studies of the surface details of stomata but also in resolving the structures and relationships that exist between the guard and subsidiary cells. We now report the isolation and SEM studies of guard cells from nine genera of plants.Guard cells were isolated from the following plants: Psilotum nudum, four species of Equisetum, Cycas revoluta, Ceratozamia sp., Pinus sylvestris, Ephedra cochuma, Welwitschia mirabilis, Euphorbia tirucalli and Allium cepa.

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An Electron Microscope Study of Interdiffusion and Compound Formation in Ta-Au Thin Films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070606 ◽

1973 ◽

Vol 31 ◽

pp. 32-33 ◽

Cited By ~ 1

Author(s):

T. C. Tisone ◽

S. Lau

Keyword(s):

Electron Microscope ◽

Electron Microscope Study ◽

Thermally Grown Oxide ◽

Ion Milling ◽

Compound Formation ◽

Technology Application ◽

Transmission Electron ◽

Before And After ◽

Au Thin Films

In a study of the properties of a Ta-Au metallization system for thin film technology application, the interdiffusion between Ta(bcc)-Au, βTa-Au and Ta2M-Au films was studied. Considered here is a discussion of the use of the transmission electron microscope(TEM) in the identification of phases formed and characterization of the film microstructures before and after annealing.The films were deposited by sputtering onto silicon wafers with 5000 Å of thermally grown oxide. The film thicknesses were 2000 Å of Ta and 2000 Å of Au. Samples for TEM observation were prepared by ultrasonically cutting 3mm disks from the wafers. The disks were first chemically etched from the silicon side using a HNO3 :HF(19:5) solution followed by ion milling to perforation of the Au side.

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Electron Microscope Study of RNA's of Paramyxoviruses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100094231 ◽

1972 ◽

Vol 30 ◽

pp. 196-197

Author(s):

Ruchama Baum ◽

J.T. Seto

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Electron Microscope Study ◽

Sendai Virus ◽

Sodium Dodecyl ◽

Rna Molecules ◽

Virus Particles ◽

Molecular Weights ◽

Length Measurements

The ribonucleic acid (RNA) of paramyxoviruses has been characterized by biochemical and physiochemical methods. However, paramyxovirus RNA molecules have not been studied by electron microscopy. The molecular weights of these single-stranded viral RNA molecules are not known as yet. Since electron microscopy has been found to be useful for the characterization of single-stranded RNA, this investigation was initiated to examine the morphology and length measurements of paramyxovirus RNA's.Sendai virus Z strain and Newcastle disease virus (NDV), Milano strain, were used. For these studies it was necessary to develop a method of extracting RNA molecules from purified virus particles. Highly purified Sendai virus was treated with pronase (300 μg/ml) at 37°C for 30 minutes and the RNA extracted by the sodium dodecyl sulfate (SDS)-phenol procedure.

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The value of Electron Microscope studies of imperfect natural diamonds

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100174102 ◽

1990 ◽

Vol 48 (4) ◽

pp. 194-195

Author(s):

J C Walmsley ◽

A R Lang

Keyword(s):

Electron Microscope ◽

Classification Scheme ◽

Natural Diamond ◽

Sudden Change ◽

Growth Conditions ◽

Diamond Growth ◽

Major Constituent ◽

Natural Diamonds ◽

Type Ia ◽

Platelet Defects

Interest in the defects and impurities in natural diamond, which are found in even the most perfect stone, is driven by the fact that diamond growth occurs at a depth of over 120Km. They display characteristics associated with their origin and their journey through the mantle to the surface of the Earth. An optical classification scheme for diamond exists based largely on the presence and segregation of nitrogen. For example type Ia, which includes 98% of all natural diamonds, contain nitrogen aggregated into small non-paramagnetic clusters and usually contain sub-micrometre platelet defects on {100} planes. Numerous transmission electron microscope (TEM) studies of these platelets and associated features have been made e.g. . Some diamonds, however, contain imperfections and impurities that place them outside this main classification scheme. Two such types are described.First, coated-diamonds which possess gem quality cores enclosed by a rind that is rich in submicrometre sized mineral inclusions. The transition from core to coat is quite sharp indicating a sudden change in growth conditions, Figure 1. As part of a TEM study of the inclusions apatite has been identified as a major constituent of the impurity present in many inclusion cavities, Figure 2.

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