scholarly journals Абляция кремния в воздухе моно- и бихроматическими импульсами лазерного излучения с длинами волн 355 и 532 nm

2022 ◽  
Vol 92 (1) ◽  
pp. 36
Author(s):  
А.Н. Чумаков ◽  
В.В. Лычковский ◽  
И.С. Никончук ◽  
А.С. Мацукович
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Material Removal ◽  
Laser Pulses ◽  
Time Interval ◽  
Silicon Sample ◽  
Laser Irradiance ◽  
Video Registration ◽  
532 Nm ◽  
Scanning Electron

Ablation of silicon sample in air under irradiance of single and double laser pulses with wavelengths 355 and 532 nm was studied by means of optical and scanning electron microscopy, raman spectroscopy, profilometry of laser craters as well as video registration of plasma’s plume radiation in time. Dependence of specific sample’s material removal on laser fluence and time interval between coupled pulses of bichromatic laser irradiance was established. Spallation of silicon was found in broad range of irradiance parameters and parameters of craters formed by ablation and spallation under the action of bichromatic laser radiation were determined.

Microgrinding of Nanostructured Carbide Coatings: Ground Surface and Subsurface Damage Observations

2006 ◽  
Vol 304-305 ◽  
pp. 276-280 ◽  
Author(s):  
Y.H. Ren ◽  
Zhi Xiong Zhou ◽  
Zhao Hui Deng
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Material Removal ◽  
Ground Surface ◽  
Subsurface Damage ◽  
Removal Mechanism ◽  
Material Removal Mechanism ◽  
Carbide Coatings ◽  
Subsurface Layers ◽  
Scanning Electron

Surface microgrinding of the nanostructured WC/12Co coatings have been undertaken with diamond wheels under various conditions. Nondestructive and destructive approaches were utilized to assess damage in ground nanostructured coatings. Different surface and subsurface configurations were observed by scanning electron microscopy. This paper investigates the effects of microgrinding conditions on damage formation in the surface and subsurface layers of the ground nanostructured WC/12Co coatings. And the material-removal mechanism has been discussed.

Morphology of Surfaces Generated by Circular Wire Brushes

1995 ◽  
Vol 117 (1) ◽  
pp. 9-15 ◽  
Author(s):  
R. J. Stango ◽  
R. A. Fournelle ◽  
S. Chada
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aluminum Alloy ◽  
Material Removal ◽  
Qualitative Theory ◽  
Characteristic Surface ◽  
Wire Brushing ◽  
Transfer Mechanisms ◽  
Scanning Electron ◽  
Subsurface Microstructure

The characteristic surface that is generated during orthogonal wire brushing of a flat 6061-T6 aluminum workpart is examined in this paper. Scanning electron microscopy is used for characterizing the surface topography, whereas subsurface microstructure and properties of the brushed region are evaluated by both metallography and microhardness measurements. The unique topographical characteristics of the contact zone suggest material removal and subsequent redeposition onto the workpart. On the basis of the experimental observations, a qualitative theory is advanced which identifies transfer mechanisms for removal and redeposition of aluminum alloy.

Living Plants Continue to Grow After Examination by Scanning Electron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 372-373
Author(s):  
Arthur E. Sowers
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Time Interval ◽  
Stinging Nettle ◽  
Living Plant ◽  
Hydroponic Solution ◽  
Scanning Electron ◽  
Ground Part

It has been found that, within the constraints and limitations described below, the same individual living plant, Urtica pilulifera (common name - Stinging Nettle), continues to grow after repeated brief (6 minute) examination by conventional scanning electron microscopy. Fig. 1-3 show the simultaneous initiation and synchronous elongation of many epidermal hairs in the same area on the first internode of the same plant. The time interval between examinations was 24 hours.Seeds of Urtica pilulifera were germinated in vermiculite, the above ground part separated from the roots by a perpendicular cut with a razor and transferred to an hydroponic solution. Germination and transfer of the above ground parts were timed such that the plants were at a stage of morphogenesis shown in Fig. 4 at the start of the daily SEM examinations.

Scanning electron microscopy and ablation rates of hard dental tissue using 350-fs and 1-ns laser pulses

1996 ◽  
Author(s):  
Joseph Neev ◽  
Daniel S. Huynh ◽  
Claudiu C. Dan ◽  
Joel M. White ◽  
Luiz B. Da Silva ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Laser Pulses ◽  
Dental Tissue ◽  
Hard Dental Tissue ◽  
Scanning Electron

Recruitment of Labelled Monocytes by Experimental Venous Thrombi

2001 ◽  
Vol 85 (06) ◽  
pp. 1018-1024 ◽  
Author(s):  
C. L. McGuinness ◽  
J. Humphries ◽  
M. Waltham ◽  
K. G. Burnand ◽  
M. Collins ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Vessel Wall ◽  
Time Course ◽  
Thrombus Formation ◽  
Vena Cava ◽  
Steady Increase ◽  
Time Interval ◽  
Venous Thrombus ◽  
Scanning Electron

Summary Objective. Infusing monocytes that have been stimulated to produce fibrinolytic activators and factors that regulate cell proliferation, migration and maturation, might enhance venous thrombus resolution. The aim of this study was to determine the time course of infused monocyte recruitment into venous thrombus in an appropriate model of this disease. Design and Methods. Thrombus was induced in the inferior vena cava of male Wistar rats using reduced flow (80-90% stenosis). The vessel wall was examined at 1hr by scanning electron microscopy. Resolving thrombi with surrounding vena cava were obtained at 1, 7, 14 and 21 days after induction (n = 8). Sections, taken at 0.5 mm intervals (10-15 sections per thrombus), were stained using haematoxylin, Martius Scarlet Blue and antibodies against monocytes, platelets and fibrin. Sections from human venous thrombi (n = 4) were similarly stained. The area occupied by monocytes (in relative pixel units, RPU) was determined using computer aided image analysis. Peripheral rat blood monocytes were extracted, fluorescently labelled and injected intravenously into 7 rats prior to thrombus induction. Vena cava with thrombus was harvested 1 h, 2, 3, 4, 7, 14 and 25 days after induction and their fluorescence measured. The fluorescent content of the caval wall and thrombus was analysed in greater detail at 2 and 25 days after thrombus induction (n = 4 at each time interval). Results. Experimental thrombi were structurally similar to human thrombus and resolved within 14-21 days. Scanning electron microscopy showed minimal endothelial damage at 1 h with signs of early thrombus formation (platelet, red cell leukocyte and fibrin deposition). Neutrophils were the predominant leukocyte in the thrombus at 1 day, with monocytes making up only 0.3% (0.04% sem) of the area of the thrombus. There was a steady increase in thrombus monocyte content and by 21 days the percentage area of thrombus covered by monocytes had increased by over 35 fold to 11.5% (2.3% sem) (p <0.001). Initially, monocytes appeared around the edge of the thrombus and became more evenly distributed through the thrombus as resolution progressed. Labelled monocytes could be found in the circulation up to 1 week after infusion. The fluorescent content (RPU) of the thrombus increased over 25 days (mean RPU At 2 days 0.012, sem 0.005; mean RPU at 25 days 1.062, sem 0.252, p = 0.008). The number of labelled monocytes in the vessel wall peaked at 2 days and decreased thereafter.

Pathogenesis of Human Hair Defects

1974 ◽  
Vol 32 ◽  
pp. 12-13
Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Hair ◽  
Standard Techniques ◽  
Scanning Electron

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Spontaneous Cataract in Nude Athymic Mice

1977 ◽  
Vol 35 ◽  
pp. 512-513
Author(s):  
Ronald H. Bradley ◽  
R. S. Berk ◽  
L. D. Hazlett
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nude Mouse ◽  
Cellular Immunity ◽  
Phosphate Buffer ◽  
Osmium Tetroxide ◽  
Athymic Mice ◽  
Transmission Microscopy ◽  
Mouse Lens ◽  
Scanning Electron

The nude mouse is a hairless mutant (homozygous for the mutation nude, nu/nu), which is born lacking a thymus and possesses a severe defect in cellular immunity. Spontaneous unilateral cataractous lesions were noted (during ocular examination using a stereomicroscope at 40X) in 14 of a series of 60 animals (20%). This transmission and scanning microscopic study characterizes the morphology of this cataract and contrasts these data with normal nude mouse lens.All animals were sacrificed by an ether overdose. Eyes were enucleated and immersed in a mixed fixative (1% osmium tetroxide and 6% glutaraldehyde in Sorenson's phosphate buffer pH 7.4 at 0-4°C) for 3 hours, dehydrated in graded ethanols and embedded in Epon-Araldite for transmission microscopy. Specimens for scanning electron microscopy were fixed similarly, dehydrated in graded ethanols, then to graded changes of Freon 113 and ethanol to 100% Freon 113 and critically point dried in a Bomar critical point dryer using Freon 13 as the transition fluid.

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

1971 ◽  
Vol 29 ◽  
pp. 410-411 ◽  
Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Osmium Tetroxide ◽  
External Surface ◽  
Three Dimensional ◽  
Surface Structures ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

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