Étude au microscope électronique à balayage de la bulbille de Huperzia selago (L.) Bernh. (Lycopodium) : méristème apical, initiation foliaire et phyllotaxie

1982 ◽  
Vol 60 (5) ◽  
pp. 667-673
Author(s):  
Emmeline Vindt-Balguerie
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Shoot Apex ◽  
Apical Meristem ◽  
Cell Number ◽  
Point Of View ◽  
Scanning Electron ◽  
Shape And Size

The shoot apex of the bulbil of Huperzia selago (L.) Bernh. (Lycopodium) has been examined by scanning electron microscope. From an ontogenic point of view, changes in shape and size have been observed in the apical meristem. Successive minimal and maximal areas of this meristem are described during a plastochron. Area and cell number are also quantified with the scanning electron microscope. Only one leaf is initiated at the beginning of each plastochron, and the two contact parastichies observed in the shoot apex of the mature bulbil are two foliar helices.

The Alteration of the Pore Spaces in Sandstones

1973 ◽  
Vol 31 ◽  
pp. 210-211
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Other ◽  
Coarse Grained ◽  
Depositional Fabric ◽  
Soluble Components ◽  
Scanning Electron ◽  
Shape And Size

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.

scholarly journals Características palinológicas de las araliáceas de México

2017 ◽  
pp. 117 ◽  
Author(s):  
Victoria Sosa
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Light Microscope ◽  
Pollen Grains ◽  
Point Of View ◽  
Generic Level ◽  
Dichotomous Key ◽  
Pollen Characters ◽  
Scanning Electron

This work studies 17 species of mexican Araliaceae from the palynological point of view belonging to the genera Aralia, Dendropanax, Didymopanax, Redera, Oreopanax y Sciadodendron . All the pollen descriptions are presented at the generic level. The grains were studied based in scanning electron microscope and light microscope. It includes a dichotomous key for the genera grains. The results showed few differences between the pollen grains of the genera although some exine characters are important. Redera and Didymopanax presented an exine semi-tectate and the rest of the genera had tectate-perforate grains. This paper compared also some pollen characters with morphological ones, finding pollen characters considered primitive correlated with characters of primitive Araliaceae groups .

Spore surface morphology of pine stem rusts of Canada as observed under a scanning electron microscope

1971 ◽  
Vol 49 (3) ◽  
pp. 371-372 ◽  
Author(s):  
Y. Hiratsuka
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Morphology ◽  
Spore Surface ◽  
Endocronartium Harknessii ◽  
Scanning Electron ◽  
Shape And Size

Two types of surface markings on the aeciospores of five pine stem rusts occurring in Canada were observed under a scanning electron microscope. Spores of four species, Endocronartium harknessii (J. P. Moore) Y. Hiratsuka (= Peridermium harknessii J. P. Moore), Cronartium coleosporioides Arth. (= P. stalactiforme Arth. & Kern), C. comptoniae Arth., and C. ribicola J. C. Fisch., had annulated processes with five to seven layers and each spore had a smooth area. The smooth area was at the same level as the top layer of the processes. Each species could be distinguished by the shape and size of its processes. Spores of Cronartium comandrae Pk. had no smooth areas and had obtuse or cuspidate processes with no annulations. Different ontogenies were apparent for the two types of spore surface markings.

Effect of Different Abrasives on Chemical Mechanical Polishing for Magnesia Alumina Spinel

2020 ◽  
Vol 866 ◽  
pp. 115-124
Author(s):  
Zhan Kui Wang ◽  
Ming Hua Pang ◽  
Jian Xiu Su ◽  
Jian Guo Yao
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Chemical Mechanical Polishing ◽  
Removal Rate ◽  
Mechanical Polishing ◽  
Key Factors ◽  
Particle Size Analyzer ◽  
Scanning Electron ◽  
Shape And Size

In this paper, a series of chemical mechanical polishing (CMP) experiments for magnesia alumina (Mg-Al) spinel were carried out with different abrasives, and the materials removal rate (MRR) and surface quality was evaluated to explore their different effects. The scanning electron microscope (SEM) and laser particle size analyzer were also employed to test the micro-shape and size distribution of abrasives. Then, the mechanism of different effects with different abrasives was analyzed in CMP for Mg-Al spinel. Those experimental results suggest that different subjecting pressure ratios of abrasives to polishing pad with different abrasive are the key factors leading to difference polishing performances in CMP.

Redefinition of Denisiella Folsom & Mills, 1938 (Collembola: Sminthurididae) with description of three new species from Brazil

Zootaxa ◽  
2018 ◽  
Vol 4434 (1) ◽  
pp. 111
Author(s):  
JOSÉ G. PALACIOS-VARGAS ◽  
AILA SOARES FERREIRA ◽  
DOUGLAS ZEPPELINI
Keyword(s):  
Electron Microscope ◽  
New Species ◽  
Scanning Electron Microscope ◽  
Antennal Segment ◽  
Different Shapes ◽  
Three New Species ◽  
New Diagnosis ◽  
Scanning Electron ◽  
Shape And Size

A new diagnosis of Denisiella is provided, based on the revision of most descriptions, including three new species from Brazil. New Brazilian taxa share the presence of 6 + 6 eyes, 4 + 4 serrate spine-like on tibiotarsi III and the polycarinate setae on tibiotarsi II but differ from each other by the shape and size of the sensilla of the tibiotarsi I. Denisiella rhizophorae sp. nov. has the combination of sensilla on tibiotarsi I of rhagidial type and C2 blunt on antennal segment III. Only D. betschi sp. nov. has barbulate spines on head and D. caatingae sp. nov. is the only which males present nasal organ. They are illustrated with drawings and scanning electron microscope photographs. Three different shapes of sensilla in the tibiotarsi I were observed and were compared with other species. 

scholarly journals ANALYZING THE EFFECT OF MICRO RUBBER, MICRO SIO2, AND NANO SIO2 IN MICROCRACKS IN SELF-CONSOLIDATING CONCRETE (SEM OBSERVATION)

2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Ehsan Adili ◽  
Moein Riginejad
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Secondary Electron ◽  
Point Of View ◽  
The Other ◽  
Self Consolidating Concrete ◽  
Nano Sio2 ◽  
Rubber Waste ◽  
Scanning Electron

The present study is an attempt to analyze the effect of micro rubber waste in self- consolidating concrete (SCC) and to compare the concrete containing SCC with conventional additives such as micro SiO2 and nano SiO2. The use of rubber waste can be substantially important from the environmental point of view. Hence, concrete specimens containing 1, 3 and 5% micro rubber waste were made. Moreover, specimens containing 1, 3 and 5% nano SiO2 and 4, 8 and 12% micro SiO2 were prepared to compare their behaviour and microstructure with each other and with the witness specimens. The effect of the other parameters such as the specimen age and the w/c ratio on the microstructure of concrete containing rubber waste was also studied. Thereafter, the specimens were imaged using a scanning electron microscope (SEM) to observe and compare the microcracks in the concrete and secondary electron beam (SE) was used to obtain their images. The results of the microstructural consideration of different specimens showed that 1% of micro rubber waste can improve the behaviour of self-consolidating concrete, but the concrete microstructure strength and quality decline with an increase in its amount.

scholarly journals Floral Initiation and Development in Aquilegia

HortScience ◽  
1990 ◽  
Vol 25 (3) ◽  
pp. 294-296 ◽  
Author(s):  
J.W. White ◽  
H. Chen ◽  
X. Zhang ◽  
D.J. Beattie ◽  
H. Grossman
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Diurnal Variation ◽  
Apical Meristem ◽  
Cold Treatment ◽  
Floral Initiation ◽  
Floral Buds ◽  
Fluorescent Lamps ◽  
Growth Room ◽  
Scanning Electron

Floral initiation and development of greenhouse and growth room-grown Aquilegia × hybrida Sims cultivars were studied using a scanning electron microscope. All greenhouse-grown cultivars initiated floral buds before cold treatment, ≈ 5 months after sowing. Floral initiation occurred at the apical meristem and proceeded acropetally on an elongated conical axis in the sequence: sepals, petals, stamens, stamenodia, and carpels. In a second experiment, 13 Aquilegia cultivars, three of which had been used in the first experiment, were grown as seedlings in a growth room at 20C under an 8-, 12-, 16-, or 20-hr photoperiod, each totaling 10.2 mol·day-1·m-2 irradiance from cool-white fluorescent lamps. Here, floral initiation was absent even after 7 months from sowing, presumably because there was no diurnal variation in irradiance or temperature.

Synthesis and Analysis of Carbide-Derived Carbon from TiC by Chlorination

2014 ◽  
Vol 602-603 ◽  
pp. 463-466 ◽  
Author(s):  
Jin Jia ◽  
Yuan Yuan Zhu ◽  
Ya Fei Zhang ◽  
Ruo Yu Chen ◽  
Bao Lin Xing ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raman Spectroscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbide Derived Carbon ◽  
Scanning Electron ◽  
Shape And Size

Carbide-derived carbons (CDCs) are produced from carbides by removing non-carbon elements in the process of selective etching. In this paper, CDC was prepared from TiC by chlorination at the temperature range of 600~1100°C. In the chlorinating process, carbide-derived carbon with different microstructure was obtained by controlling the reaction temperature. The structures of CDC were revealed with X-ray diffraction and Raman spectroscopy. The morphologies of CDC were analyzed by scanning electron microscope. From X-ray diffraction analysis, the CDC obtained from TiC in this experiment mainly consisted of amorphous carbon. Basing on scanning electron microscopy, carbide-derived carbon from TiC maintained the shape and size of TiC particles. Keywords: Carbide-derived carbons; chlorination; TiC

scholarly journals Electrochemically Developed Micro/Nanostructures in Single Ion Track Filters As a New Pattern

2015 ◽  
Vol 12 (1) ◽  
pp. 50-53
Author(s):  
S Kaur
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electroless Deposition ◽  
Pore Shape ◽  
Pattern Synthesis ◽  
Morphological Studies ◽  
Nano Structures ◽  
Track Membranes ◽  
Scanning Electron ◽  
Shape And Size

The technique of pattern synthesis using potentiostatic electroless deposition is a very weighty process for fabrication of micro/nano structures and is cheap and simple. In this paper, electrochemical/electroless deposition have been used to develop copper micro/nanostructures within the micro/nanochannels of single ion track membranes. Scanning electron microscope was used for morphological studies. These micro/nanostructures have uniform diameters of 5µm and 200nm which is equivalent to the pore shape and size of the pattern used.

scholarly journals Scanning Electron Microscope Studies of the Development from Germination to Mature Plant of Some Hardy Terrestrial Orchids

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 870F-871
Author(s):  
Erika Szendrák ◽  
Paul E. Read ◽  
Eszter R. Eszéki ◽  
Elizabeth Jámbor-Benczúi ◽  
Aniko Csillag
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Apical Meristem ◽  
In Vitro Cultures ◽  
Plant Materials ◽  
Orchid Species ◽  
Terrestrial Orchids ◽  
Last Stage ◽  
Scanning Electron

Cultures of several orchid species [Barlia robertiana (Loisel.), Dactylorhiza fúchsii Soó, D. incarnata (L.) Soó, D. maculata (L.) Soó, D. majalis (Rchb.), D. saccifera (Brong) Soó, D. sambucina (L.) Soó, Gymnadenia conopsea (L.) R.Br., Himantoglossurn hircinum (L.) Spreng., Ophris sphegodes Mill., Orchis coriophora ssp. fragrans L., Orchis laxiflora ssp. palustris Lam., Orchis mascula L., Orchis morio L., Platanthera bifolia (L.) Rich., Spiranthes aestivalis (Poir.) Rich.] were initiated with fresh ripe seeds from desiccated fruit and 4-month-old in vitro seedlings. The medium used for both germination and seedling culture was a modified FAST medium. Samples for the scanning electron microscope (SEM) surveys were taken from the in vitro cultures and some plant materials were collected from their native habit. Samples were observed with a Tesla BS 300 SEM. Seeds ranged from 300 to 450 μm in length and were flask-shaped. The first germination step is opening of the seedcoat, when the first few white cells will be visible. After a few weeks, the apical meristem appears. The young protocorm is covered with numerous translucent rhizoids. In the last stage of germination, the first root and the first true leaf start to develop. After 2 years, they are suitable for transfer ex vitro. Structure of the mature organs and tissues can be examined at this stage.

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