Microscopic investigation on sintering mechanism of electronic silver paste and its effect on electrical conductivity of sintered electrodes

Microstructure, precipitation hardening response, and mechanical and physical properties of Cu-Cr-Ag alloy and Cu-Cr-Ag-Ce alloy have been investigated using transmission electron microscopy, scanning electron microscope, optical microscope, electrical conductivity analysis, and tensile test. The influence of element Ce on the matrix refinement, impurity removal, and precipitation in the Cu-Cr-Ag alloys has been analyzed. The experimental results show that the strength and electrical conductivity of Ce containing alloys are greater than those of Ce-free alloys after each processing step. Improvement of strength and electrical conductivity of the Cu-Cr-Ag alloy by adding Ce element is attributed to removing oxygen and sulfur from as-cast alloy.

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Fabrication of high performance printed flexible conductors by doping of polyaniline nanomaterials into silver paste

Journal of Materials Chemistry C ◽

10.1039/c8tc05391j ◽

2019 ◽

Vol 7 (5) ◽

pp. 1188-1197 ◽

Cited By ~ 13

Author(s):

Jiayue Wen ◽

Yanhong Tian ◽

Changxiang Hao ◽

Shang Wang ◽

Zhipeng Mei ◽

...

Keyword(s):

Electrical Conductivity ◽

High Performance ◽

Mechanical Stability ◽

Silver Paste ◽

Conductive Composites

An innovation application of doping conjugated polyaniline nano-dendrites (PANIs) into electrical conductive composites (ECCs) to prepare advanced flexible or stretchable printing circuits with better electrical conductivity and mechanical stability.

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Removing Substrate Background in TEM Microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052857 ◽

1974 ◽

Vol 32 ◽

pp. 568-569

Author(s):

John C. Russ ◽

Nicholas C. Barbi

Keyword(s):

Electrical Conductivity ◽

Rapid Growth ◽

Organic Film ◽

Absolute Concentration ◽

Background Signal ◽

X Ray ◽

Elemental Concentrations ◽

Transmission Electron ◽

Electron Microscopes ◽

The Continuum

The rapid growth of interest in attaching energy-dispersive x-ray analysis systems to transmission electron microscopes has centered largely on microanalysis of biological specimens. These are frequently either embedded in plastic or supported by an organic film, which is of great importance as regards stability under the beam since it provides thermal and electrical conductivity from the specimen to the grid.Unfortunately, the supporting medium also produces continuum x-radiation or Bremsstrahlung, which is added to the x-ray spectrum from the sample. It is not difficult to separate the characteristic peaks from the elements in the specimen from the total continuum background, but sometimes it is also necessary to separate the continuum due to the sample from that due to the support. For instance, it is possible to compute relative elemental concentrations in the sample, without standards, based on the relative net characteristic elemental intensities without regard to background; but to calculate absolute concentration, it is necessary to use the background signal itself as a measure of the total excited specimen mass.

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Macromolecular structures of biological specimens are not obscured by controlled osmium impregnation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100076639 ◽

1983 ◽

Vol 41 ◽

pp. 606-607

Author(s):

Klaus-Ruediger Peters ◽

Samuel A. Green

Keyword(s):

Thin Films ◽

Electrical Conductivity ◽

Critical Point ◽

Metal Films ◽

High Magnification ◽

Osmium Impregnation ◽

Instrumental Resolution ◽

20 Nm ◽

Continuous Metal

High magnification imaging of macromolecules on metal coated biological specimens is limited only by wet preparation procedures since recently obtained instrumental resolution allows visualization of topographic structures as smal l as 1-2 nm. Details of such dimensions may be visualized if continuous metal films with a thickness of 2 nm or less are applied. Such thin films give sufficient contrast in TEM as well as in SEM (SE-I image mode). The requisite increase in electrical conductivity for SEM of biological specimens is achieved through the use of ligand mediated wet osmiuum impregnation of the specimen before critical point (CP) drying. A commonly used ligand is thiocarbohvdrazide (TCH), first introduced to TEM for en block staining of lipids and glvcomacromolecules with osmium black. Now TCH is also used for SEM. However, after ligand mediated osinification nonspecific osmium black precipitates were often found obscuring surface details with large diffuse aggregates or with dense particular deposits, 2-20 nm in size. Thus, only low magnification work was considered possible after TCH appl ication.

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Light and electron microscopic investigation of adenohypophyses of germfree, food-restricted, and germfree-food restricted aging, male lobund-wistar rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103826 ◽

1988 ◽

Vol 46 ◽

pp. 352-353

Author(s):

G. Ilse ◽

K. Kovacs ◽

N. Ryan ◽

T. Sano ◽

L. Stefaneanu ◽

...

Keyword(s):

Wistar Rats ◽

Microscopic Investigation ◽

Electron Microscopic Investigation ◽

Aging Male ◽

Sprague Dawley ◽

Electron Microscopic ◽

Sprague Dawley Rats ◽

Old Rats ◽

Ad Libitum ◽

Microscopic Findings

Germfree state and food restriction have been shown to increase life span and delay tumor occurrence in rats. We report here the histologic, immunocytochemical and electron microscopic findings of adenohypophyses of aging, male Lobund-Wistar rats raised at Lobund Laboratories. In our previous study, the morphologic changes in the adenohypophyses of old rats have been extensively investigated by histology, immunocytochemistry and electron microscopy. Lactotroph adenomas were frequent in Long-Evans and Sprague-Dawley rats, whereas gonadotroph adenomas were frequent in Sprague-Dawley and Wistar rats.Male Lobund-Wistar rats were divided into four groups: 1) conventional, which were raised under normal non-germfree environment and received food ad libitum; 2) germfree-food ad libitum; 3) conventional environment-food restricted and 4) germfree-food restricted. The adenohypophyses were removed from 6-month-, 18-month- and 30-month-old rats. For light microscopy, adenohypophyses were fixed in formalin and embedded in paraffin.

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An Electron Microscopic Study of the Acute Effects of Hypothalamic Releasing Factors on the Anterior Pituitary Gland

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100901 ◽

1968 ◽

Vol 26 ◽

pp. 232-233

Author(s):

P.W. Coates ◽

E.A. Ashby ◽

L. Krulich ◽

A. Dhariwal ◽

S. McCann

Keyword(s):

Anterior Pituitary ◽

Microscopic Investigation ◽

Uranyl Acetate ◽

Electron Microscopic Investigation ◽

Electron Microscopic ◽

Tissue Samples ◽

Thin Sections ◽

Dense Membrane ◽

Membrane Bound ◽

Releasing Factors

The morphologic effects on somatotrophs of crude sheep hypothalamic extract prepared from stalk-median eminence were studied by electron microscopy in conjunction with concurrently run bioassays performed on the same tissue samples taken from young adult male Sherman rats.Groups were divided into uninjected controls and injected experimentals sacrificed at 5', 15', and 30' after injection. Half of each anterior pituitary was prepared for electron microscopic investigation, the other half for bioassay. Fixation using collidine buffered osmium tetroxide was followed by dehydration and embedment in Maraglas. Uranyl acetate and lead citrate were used as stains. Thin sections were examined in a Philips EM 200.Somatotrophs from uninjected controls appeared as described in the literature (Fig. 1). In addition to other components, these cells contained moderate numbers of spherical, electron-dense, membrane-bound granules approximately 350 millicrons in diameter.

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Fine Structural Classification of Chromophobe Adenomas of the Human Pituitary Gland

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100115511 ◽

1975 ◽

Vol 33 ◽

pp. 378-379

Author(s):

K. Kovacs ◽

E. Horvath

Keyword(s):

Pituitary Adenomas ◽

Secretory Activity ◽

Microscopic Investigation ◽

Uranyl Acetate ◽

Electron Microscopic Investigation ◽

Electron Microscopic ◽

Human Pituitary ◽

Cytoplasmic Staining ◽

Human Pituitary Gland ◽

Microscopic Features

Chromophobe pituitary adenomas arise from adenohypophysial cells and fail to exhibit cytoplasmic staining with conventional acid or basic dyes by light microscopy. The aim of the present work was to study the electron microscopic features of these tumors, to separate them into distinct entities and to correlate their fine structural appearances with secretory activity.Among 48 surgically removed various pituitary adenomas 30 tumors were found which, based on the tinctorial characteristics of the cytoplasm, corresponded to chromophobe adenomas. For electron microscopic investigation pieces of these tumors were fixed in 2.5 per cent glutaraldehyde in Sorensen's buffer, post fixed in 1 per cent osmium tetroxide in Millonig's buffer, dehydrated in graded ethanol and embedded in Epon 812. Ultrathin sections were stained with uranyl acetate and lead citrate.By electron microscopy it was possible to separate chromophobe adenomas into 3 distinct entities: 1) adenomas consisting of sparsely granulated growth hormone cells (7 cases).

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