Seed surface morphology in few Swertia species-A tool for species identification

Aquilegia yangii (Ranunculaceae), a new species from western China, is described and illustrated. The new species is similar to A. oxysepala and A. kansuensis. However, there are differences in reproductive structure, especially flower size, petal shape, anther colour and seed surface, between the new species and the other two species. The seed surface morphology of the new species is also described in this study.

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Reduction of Dislocation Density of SiC Crystals Grown on Seeds after H2 Etching

Materials Science Forum ◽

10.4028/www.scientific.net/msf.897.19 ◽

2017 ◽

Vol 897 ◽

pp. 19-23 ◽

Cited By ~ 1

Author(s):

Xiu Fang Chen ◽

Fu Sheng Zhang ◽

Xiang Long Yang ◽

Yan Peng ◽

Xue Jian Xie ◽

...

Keyword(s):

Dislocation Density ◽

Surface Morphology ◽

Surface Damage ◽

Subsurface Damage ◽

Bulk Crystals ◽

Force Microscopy ◽

Seed Surface ◽

Atomic Force ◽

Order Of Magnitude ◽

Band Contrast

Three-inch 6H-SiC bulk crystals were grown by the PVT method on the seeds processed by different treatments. The influences of seed surface morphology and subsurface damage on the dislocation density were investigated. The seed surface morphology was characterized by atomic force microscopy (AFM). The extent of the subsurface damage was estimated by electron back-scattered diffraction (EBSD) and Band Contrast (BC) value. The distribution and density of the dislocations were observed by optical microscopy (OM). The results showed that the pit density performed by H2 1400°C etching was nearly one order of magnitude lower than that by mechanical polishing (MP) process. So H2 etching processed at 1400°C for 2h could completely remove the subsurface damage, compared with the MP process with the deep surface damage.

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Seed surface morphology in some representatives of the Genus Rhodiola sect. Rhodiola (Crassulaceae) in the Russian Far East

Flora ◽

10.1016/j.flora.2008.01.009 ◽

2009 ◽

Vol 204 (1) ◽

pp. 17-24 ◽

Cited By ~ 22

Author(s):

Svetlana B. Gontcharova ◽

Andrey A. Gontcharov ◽

Valentin V. Yakubov ◽

Katsuhiko Kondo

Keyword(s):

Surface Morphology ◽

Russian Far East ◽

Far East ◽

Seed Surface ◽

The Russian Far East

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An Established Epithelial Cell Line (NPC/HK1) from a Nasopharyngeal Carcinoma - II. A Sem Study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053784 ◽

1982 ◽

Vol 40 ◽

pp. 224-225

Author(s):

Li C.L. ◽

Chew E.C. ◽

Huang D.P. ◽

Ho H.C. ◽

Mak L.S. ◽

...

Keyword(s):

Nasopharyngeal Carcinoma ◽

Epithelial Cell ◽

Surface Morphology ◽

Cell Line ◽

Epithelial Cell Line ◽

Present Communication ◽

Cells In Culture ◽

Sem Study ◽

Well Differentiated

An epithelial cell line, NPC/HK1, has recently been successfully established from a nasopharyngeal carcinoma of the moderately to well differentiated squamous type. The present communication reports on the surface morphology of the NPC/HK1 cells in culture.

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Chemical Species Identification in an SEM by Changes in Emitted X-Ray Energies

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052869 ◽

1974 ◽

Vol 32 ◽

pp. 570-571

Author(s):

R. H. Duff

Keyword(s):

Species Identification ◽

Valence Electron ◽

Chemical Species ◽

X Rays ◽

Chemical Bonds ◽

Small Shift ◽

X Ray ◽

Electron Transitions ◽

Peak Energy ◽

Chemical Combination

A material irradiated with electrons emits x-rays having energies characteristic of the elements present. Chemical combination between elements results in a small shift of the peak energies of these characteristic x-rays because chemical bonds between different elements have different energies. The energy differences of the characteristic x-rays resulting from valence electron transitions can be used to identify the chemical species present and to obtain information about the chemical bond itself. Although these peak-energy shifts have been well known for a number of years, their use for chemical-species identification in small volumes of material was not realized until the development of the electron microprobe.

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Specimen Collection Effect in Scanning Electron Microscopy Images

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095492 ◽

1972 ◽

Vol 30 ◽

pp. 448-449

Author(s):

J. Temple Black ◽

Jose Guerrero

Keyword(s):

Surface Morphology ◽

Secondary Electron Emission ◽

Secondary Electrons ◽

Charge Effects ◽

Material Density ◽

Specimen Collection ◽

The Subject ◽

Curved Paths ◽

Subject Material ◽

Microscopy Images

In the SEM, contrast in the image is the result of variations in the volume secondary electron emission and backscatter emission which reaches the detector and serves to intensity modulate the signal for the CRT's. This emission is a function of the accelerating potential, material density, chemistry, crystallography, local charge effects, surface morphology and especially the angle of the incident electron beam with the particular surface site. Aside from the influence of object inclination, the surface morphology is the most important feature In producing contrast. “Specimen collection“ is the name given the shielding of the collector by adjacent parts of the specimen, producing much image contrast. This type of contrast can occur for both secondary and backscatter electrons even though the secondary electrons take curved paths to the detector-collector.Figure 1 demonstrates, in a unique and striking fashion, the specimen collection effect. The subject material here is Armco Iron, 99.85% purity, which was spark machined.

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The Effect of Benzene on Bluegill Olfactory Lamellae

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010011965x ◽

1985 ◽

Vol 43 ◽

pp. 574-575

Author(s):

D.R. Mattie ◽

J.W. Fisher

Keyword(s):

Surface Morphology ◽

Soluble Fraction ◽

Lepomis Macrochirus ◽

Sublethal Concentration ◽

Water Soluble ◽

Major Constituent ◽

Jet Fuels ◽

Aquatic Biota ◽

Normal Surface ◽

Cacodylate Buffer

Jet fuels such as JP-4 can be introduced into the environment and come in contact with aquatic biota in several ways. Studies in this laboratory have demonstrated JP-4 toxicity to fish. Benzene is the major constituent of the water soluble fraction of JP-4. The normal surface morphology of bluegill olfactory lamellae was examined in conjunction with electrophysiology experiments. There was no information regarding the ultrastructural and physiological responses of the olfactory epithelium of bluegills to acute benzene exposure.The purpose of this investigation was to determine the effects of benzene on the surface morphology of the nasal rosettes of the bluegill sunfish (Lepomis macrochirus). Bluegills were exposed to a sublethal concentration of 7.7±0.2ppm (+S.E.M.) benzene for five, ten or fourteen days. Nasal rosettes were fixed in 2.5% glutaraldehyde and 2.0% paraformaldehyde in 0.1M cacodylate buffer (pH 7.4) containing 1.25mM calcium chloride. Specimens were processed for scanning electron microscopy.

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Observation of surface morphology by reflection electron holography

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154652 ◽

1989 ◽

Vol 47 ◽

pp. 536-537

Author(s):

N. Osakabe ◽

J. Endo ◽

T. Matsuda ◽

A. Tonomura

Keyword(s):

Phase Shift ◽

Surface Morphology ◽

High Sensitivity ◽

High Energy ◽

Path Difference ◽

Transmission Mode ◽

Electron Holography ◽

Dynamical Process ◽

High Vertical Resolution ◽

Amplification Technique

Progress in microscopy such as STM and TEM-TED has revealed surface structures in atomic dimension. REM has been used for the observation of surface dynamical process and surface morphology. Recently developed reflection electron holography, which employes REM optics to measure the phase shift of reflected electron, has been proved to be effective for the observation of surface morphology in high vertical resolution ≃ 0.01 Å.The key to the high sensitivity of the method is best shown by comparing the phase shift generation by surface topography with that in transmission mode. Difference in refractive index between vacuum and material Vo/2E≃10-4 owes the phase shift in transmission mode as shownn Fig. 1( a). While geometrical path difference is created in reflection mode( Fig. 1(b) ), which is measured interferometrically using high energy electron beam of wavelength ≃0.01 Å. Together with the phase amplification technique , the vertivcal resolution is expected to be ≤0.01 Å in an ideal case.

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Defect morphology in thick relaxed layers of InGaAs on GaAs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176472 ◽

1990 ◽

Vol 48 (4) ◽

pp. 668-669

Author(s):

R H Dixon ◽

P Kidd ◽

P J Goodhew

Keyword(s):

Electron Microscopy ◽

Surface Morphology ◽

Growth Conditions ◽

X Ray Diffraction ◽

Double Crystal ◽

Strained Layers ◽

Good Surface ◽

Transmission Electron ◽

Device Structures ◽

Surface Morphologies

Thick relaxed InGaAs layers grown epitaxially on GaAs are potentially useful substrates for growing high indium percentage strained layers. It is important that these relaxed layers are defect free and have a good surface morphology for the subsequent growth of device structures.3μm relaxed layers of InxGa1-xAs were grown on semi - insulating GaAs substrates by Molecular Beam Epitaxy (MBE), where the indium composition ranged from x=0.1 to 1.0. The interface, bulk and surface of the layers have been examined in planar view and cross-section by Transmission Electron Microscopy (TEM). The surface morphologies have been characterised by Scanning Electron Microscopy (SEM), and the bulk lattice perfection of the layers assessed using Double Crystal X-ray Diffraction (DCXRD).The surface morphology has been found to correlate with the growth conditions, with the type of defects grown-in to the layer (e.g. stacking faults, microtwins), and with the nature and density of dislocations in the interface.

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