• Journal of the Korean Society for Precision Engineering
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• v.25 no.4
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• pp.53-60
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• 2008

Electron detectors used in scanning electron microscope accept electrons emitted from the specimen and convert them to an electrical signal that, after amplification, is used to modulate the gray-level intensities on a cathode ray tube, producing an image of the specimen. Electron detector is one of the key components dominating the performance of scanning electron microscope so that the development of electron detectors having high performance is indispensable to acquire high quality images using scanning electron microscope. In this paper, we designed and manufactured an electron detector and conducted a couple of image capture experiments using it. In particular, scintillator which generates light photons when it is struck by high-energy electrons was manufactured and experimental studies on the optimization of manufacturing condition was carried out. From experiments to evaluate the performance of our detector, it was verified that the performance of our detector is equivalent to or better than that of the conventional one.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.18 no.1
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• pp.137-147
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• 1988

This study was designed to investigate the effects of irradiation on the salivary ductal cells, especially on the intercalated ductal cells of the rat parotid glands. For this study, 36 Sprague-Dawley strain rats were irradiated on the head and neck region with absorbed dose of 15Gy by Co-60 teletherapy unit, Picker's model 4M60. The conditions irradiated were that field size, SSD, dose rate and depth were 12×5㎝m, 50㎝, 222 Gy/min. and 1㎝. respectively. The experimental animals were sacrificed 1, 2, 3, 6, 12 hours and 1, 3, 7 days after the irradiation and the changes of the irradiated intercalated duct cells of the parotid glands were examined under the light and electron microscope. The results were as follows: 1. Under the light and electron microscope, the nucleus, mitochondria and secretory granules showed severe changes in the early stage after irradiation and the most severe cellular de- generations were observed 2 hours after irradiation, but the repair processes began from 6 hours after irradiation. 2. Under the electron microscope, loss of the nuclear membranes, derrangement of the chromosomes, swelling and destruction of the secretory granules, and widening of the intercellular spaces were observed after irradiation. 3. Under the light microscope, atrophy and irregular proliferation of the ductal cells, cuboidal metaplasia, hyperchromatism, and the construction or obstruction of the lumen were observed after irradiation.

• Journal of Sericultural and Entomological Science
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• v.41 no.2
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• pp.87-93
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• 1999

Under Light and Scanning electron microscope, the pupal morphology of mulberry silkworm Bombyx mori Linn. revealed the prothorax and metathorax, well developed mesothorax, less defined last pair of sporacle, well exposed prothoracic femora and wing pads approaching the anterior margin of Ab III. The important sex separating characters viz, wegiht, antennal elevations, intersegmental lines and genings have discussed. Further, two separate openings bursa copulatrix and ovipositional opening were observed, performing different functions in abult moth.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1271-1276
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• 2007

The most powerful analytical equipment usually comes at the cost of having the highest demand for space. Where electron microscopes has traditionally required a room to themselves, not just for reasons of their size but because of ancillary demands for pipes and service. The simple optical microscopes, of course, can occupy the desk-top, but because their performance is limited by the wavelength of light, their powers of magnification and resolution are inferior to that of the electron microscope. Mini SEM will sit comfortably on a desk-top but offers magnification and resolution performances much closer to that of a standard SEM. This new technique extends the scope of SEM as a high-resolution microscope, relatively cheap and widely available imaging tool, for a wider variety of samples.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.298-299
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• 2008

Images of deposited layers of organic light-emitting diodes were observed by scanning-electron microscope (SEM). We were able to see a clear cross-sectional view of deposited layers. The SEM is a type of electron microscope that images the sample surface by scanning it with a high-energy beam of electrons in a raster scan pattern. A thickness of deposited layer measured by thickness monitor is close to a real value measured by a-step surface profiler within 5%. We were able to see a formation of domains of size about 50-100nm from a surface morphology of Al, and pin holes of size about 50nm.

• Biomedical Science Letters
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• v.8 no.1
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• pp.13-20
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• 2002

Asadisulphide were purified from Ferrula assafoetida by organic solvent extraction and chromatography. Since ethyl acetate extracts of F. assafoetida has the strongest inhibitory effects on adherence of HL-60 cells, it was reextracted with ethyl acetate, hexane, and ethyl ether and chromatographed three times to isolate asadisulphide. HL-60 cells were grouped into untreated control, TPA-treated, asadisulphide-teated and TPA＋asadisulphide-treated groups, and structural changes of these cells were observed using light microscope, scanning electron microscope and transmission electron microscope to examine the inhibitory effects of asadisulfide on the TPA-induced adherence of HL-60 cells. Light microscopic observations showed that asadisulphide has inhibitory effects on the cell aggregation, extention of cytoplasmic processes and inhibition of substrate adhesion of HL-60 cells. Using scanning and transmission electron microscope, it was observed that cell surfaces and several ultrastructures of TPA-treated HL-60 cell were different from control group, while there were no remarkable differences between asadisulphide-treated and TPA＋asadisulphide-treated group. These results could suggest that asadisulphide has the inhibitory effects on the TPA-induced structural changes of HL-60 cells.

• Nuclear Engineering and Technology
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• v.50 no.2
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• pp.259-267
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• 2018

Focused ion beam-scanning electron microscope and electron backscattered diffraction examinations were conducted in the center of a $73\;GWd/t_U\;UO_2$ fuel. They showed the formation of subdomains within the initial grains. The local crystal orientations in these domains were close to that of the original grain. Most of the fission gas bubbles were located on the boundaries. Their shapes were far from spherical and far from lenticular. No interlinked bubble network was found. These observations shed light on previous unexplained observations. They plead for a revision of the classical description of fission gas release mechanisms for the center of high burn-up $UO_2$. Yet, complementary detailed observations are needed to better understand the mechanisms involved.

• The Journal of Korean Medicine
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• v.20 no.3 s.39
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• pp.27-35
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• 1999

The purpose of this study was to investigate the histochemical effect of Jojoongikgi-tang (JIT) on hairless mice induced by DNCB. For the study, DNCB was applied on the infrascapular region of the mices skin and then JIT was orally administered. As a result, the following histochemical changes of the dermis were observed through light and electron microscopes, and statistical data. The results obtained were as follows: 1. In the 2 days experimental group, more histamine mast cells dermis occurred than in the control or normal group when observed under light microscope. When an electron microscope was used, histochemical reactive cells in the dermis were found as mast cells that contained more cytoplasmic granules than in the control or normal group. 2. In the 5 days experimental group, the number of mast cells were decreased over the control or normal group when observed under light microscope. When an electron microscope was used, mast cells in the control contained secretory granules with higher electron density than those of the experimental group. 3. As a result of statistical analysis, the mean value of mast cells in the normal 2 days control and experimental groups was not significantly different (p<0.05). 4. However, the mean values of it in the normal ($19.1000{\pm}6.3154$), 5 day control ($103.4500{\pm}42.2704$) and 5 day experimental groups ($35.9500{\pm}8.5746$) were significantly different (p<0.05). From the above results, it is concluded that JIT is efficient against the purpura induced by DNCB.

• Korean Journal of Plant Tissue Culture
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• v.22 no.6
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• pp.323-327
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• 1995

This experiment was carried out to observe the origin and developmental pattern of somatic embryos of Oenanthe javanica ($B^{L}.$) DC. The experiment included observation of embryogenic cells and their development stages by light microscope, transmission electron microscope and scanning electron microscope. The embryogenic cells, which were smaller than non-embryogenic cells in size with expanded nucleus and dense cytoplasm. When stained with hematoxylin, the embryogenic cells were readily distinguished from the non-embryogenic cells of which cell walls were stained with safranin. It was observed at somatic embryos developed from single cells on the epidermis of developing embryos or in the surface or inside of embryogenic clumps by segmentation pattern. Observation with a transmission electron microscope revealed that the embryogenic cells had dense cytoplasm expanded nucleus, small vacuoles, large amyloplasts containing starch grains, and abundant organelles including lipid bodies. Under a scanning electron microscope, embryogenic callus was shown to consist of very smaller cells than non-embryogenic cells in an orderly arrangement and covered with a net-like structure, while the non-embryogenic callus consisted of large cells, irregular in size and arrangement, and covered with a gelatin-like material.

• Journal of Plant Biology
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• v.3 no.2
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• pp.26-28
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• 1960

Electron-Microscopical Observalion on Fine Structure of Diatom Frustules which is collected in the East Coast of Kyung-Pook Province. Kor. Jour. Bot. 3(2) 26-28 lllus. 1960 The fine structure of Diatom frustules which is collected in the east coast of Yungil and Wul Sung, Kyung-Pook Province, is ovserved by the light microscope and hte electron-microscope, and the materials collected by auther are 1 family, 2 genus and 2 species. Coscinodiscus elegans. Greville Actinoptychus undulatus Rals Those were havitated in sea water as the plankton which were found in diatomite.