Microscopic investigations and pharmacognostic techniques for the standardization of the fruits of Rosa laxa Retz

2021 ◽  
Author(s):  
Ning Wang ◽  
Jing Sun ◽  
Shanzi Zhang ◽  
Chunyan Wang ◽  
Li Tian
Keyword(s):  
Microscopic Investigations

Convergent Beam Electron Diffraction

1978 ◽  
Vol 36 (3) ◽  
pp. 304-315
Author(s):  
G. Lehmpfuhl
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Crystal Surface ◽  
Diffraction Spot ◽  
Crystal Thickness ◽  
Large Area ◽  
Electron Microscopic ◽  
Additional Information ◽  
Microscopic Investigations

Introduction In electron microscopic investigations of crystalline specimens the direct observation of the electron diffraction pattern gives additional information about the specimen. The quality of this information depends on the quality of the crystals or the crystal area contributing to the diffraction pattern. By selected area diffraction in a conventional electron microscope, specimen areas as small as 1 µ in diameter can be investigated. It is well known that crystal areas of that size which must be thin enough (in the order of 1000 Å) for electron microscopic investigations are normally somewhat distorted by bending, or they are not homogeneous. Furthermore, the crystal surface is not well defined over such a large area. These are facts which cause reduction of information in the diffraction pattern. The intensity of a diffraction spot, for example, depends on the crystal thickness. If the thickness is not uniform over the investigated area, one observes an averaged intensity, so that the intensity distribution in the diffraction pattern cannot be used for an analysis unless additional information is available.

Determination of the phase structure of polymerblends by electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 492-493
Author(s):  
Dr. G. Kaemof
Keyword(s):  
Screw Extruder ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Single Screw Extruder ◽  
Transmission Electron ◽  
The Matrix ◽  
Twin Screw ◽  
Special Case ◽  
Microscopic Investigations

A mixture of polycarbonate (PC) and styrene-acrylonitrile-copolymer (SAN) represents a very good example for the efficiency of electron microscopic investigations concerning the determination of optimum production procedures for high grade product properties.The following parameters have been varied:components of charge (PC : SAN 50 : 50, 60 : 40, 70 : 30), kind of compounding machine (single screw extruder, twin screw extruder, discontinuous kneader), mass-temperature (lowest and highest possible temperature).The transmission electron microscopic investigations (TEM) were carried out on ultra thin sections, the PC-phase of which was selectively etched by triethylamine.The phase transition (matrix to disperse phase) does not occur - as might be expected - at a PC to SAN ratio of 50 : 50, but at a ratio of 65 : 35. Our results show that the matrix is preferably formed by the components with the lower melting viscosity (in this special case SAN), even at concentrations of less than 50 %.

Microstructure and Texture Evolution in a Cold-Rolled High Mn Steel with Microadditions of Ti and Nb

2013 ◽  
Vol 203-204 ◽  
pp. 71-76
Author(s):  
Sławomir Kołodziej ◽  
Joanna Kowalska ◽  
Wiktoria Ratuszek ◽  
Wojciech Ozgowicz ◽  
Krzysztof Chruściel
Keyword(s):  
Plastic Deformation ◽  
Texture Evolution ◽  
Hexagonal Structure ◽  
Cold Plastic Deformation ◽  
Α Phase ◽  
Ε Phase ◽  
Cold Rolled ◽  
Goss Orientation ◽  
Mn Steel ◽  
Microscopic Investigations

The aim of this work was the microstructure and texture analysis of a deformed via cold-rolling 24.5Mn-3.5Si-1.5Al-Ti-Nb TWIP/TRIP type steel. It was found, that during cold plastic deformation a phase transformation of austenite into martensite takes place. The transformation progress was confirmed by the microscopic investigations. The texture of austenite is characterized by a limited α1=||RD fibre and the γ=||ND fibre. The texture of austenite changed with increasing deformation rate. In the texture of deformed austenite the strongest orientation is the {110} Goss orientation, which belongs to the α=||ND orientation fibre. During cold plastic deformation γ→ε and γ→ε→α’ phase transformations as well as the deformation of γ, ε and α’ phases are taking place in the steel. The formed ε phase (hexagonal structure) also possesses a distinct texture.

Light and electron microscopic investigations in the Dictyonemataceae (Basidiolichens)

1977 ◽  
Vol 55 (20) ◽  
pp. 2565-2573 ◽  
Author(s):  
Robert D. Slocum ◽  
Gary L. Floyd
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cellular Level ◽  
Fungal Symbiont ◽  
Electron Microscopic ◽  
Basidiomycetous Fungus ◽  
Transmission Electron ◽  
Fungal Symbiosis ◽  
Algal Host ◽  
Microscopic Investigations

The nature of the association between the basidiomycetous mycobiont and the blue-green phycobiont in two species of the tropical basidiolichen Dictyonema was investigated using Nomarski light optics and scanning and transmission electron microscopy. Although members of this family may exhibit either a homoiomerous or heteromerous type of thallus organization, the fungus–alga relationship at the cellular level is remarkably consistent. Scytonema filaments are intimately associated with appressorial hyphae of the mycobiont and with extensive intracellular hyphae, which appear to be unrelated to the basidiomycetous fungal symbiont. This is the first report of a lichen displaying an apparent dual fungal symbiosis with the algal host. Association with the intracellular fungus produces no discernible damage to the phycobiont and apparently does not interfere with the symbiosis involving the basidiomycetous fungus.

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