• Applied Microscopy
• /
• v.28 no.3
• /
• pp.273-282
• /
• 1998

Ultrastructure of fertilized egg envelope in the tomato clown anemonefish (Amphiprion freatus) was examined by mean of light, scanning and transmission electron microscopies. The fertilized egg of tomato clown anemonefish was of non-transparent, ellipsoidal, adhesive and non-floted type, and there were numerous oil droplets in the yolk sac and adhesive filaments in the area of the animal pole. The outer surface of egg envelope was smooth. The fertilized egg envelope consisted of two distinct layers; a non-adhesive outer electron-dense layer and an inner layer, consisting of five horizontal low electron-dense lamellae alternating with the middle electron dense interlamellae.

• Corrosion Science and Technology
• /
• v.18 no.6
• /
• pp.232-242
• /
• 2019

In this study, hydrophobically modified fumed silica was added to the PVDF coating to improve corrosion protection performance. Two types of silane modifiers, trimethylchlorosilane (TMCS) and hexamethyldisilazane (HMDZ), were used for hydrophobic modification of the fumed silica. The composition of modified fumed silica was analyzed by Fourier transform infrared, X-ray photoelectron spectroscopy, and elemental analysis. The dispersion of modified fumed silica in the PVDF coating was observed by the transmission electron microscopy, and the hydrophobicity of PVDF coating was analyzed by the water contact angle. Surface properties were examined by the field emission scanning electron microscopy and scanning probe microscopy. Potentiodynamic polarization was conducted to confirm corrosion protection performance of PVDF coating in terms of hydrophobically-modified fumed silica contents. As a result, the average surface roughness and the water contact angle of the PVDF coating increased with modifier contents. The results of the potentiodynamic polarization test showed an increase of the E_corr values with increase of the hydrophobicity of PVDF coating. Thus, it clearly indicates that the corrosion protection performance of PVDF coating improved with the addition of the hydrophobic-modified fumed silica that prevents the penetration of moisture into the PVDF coating.

• Applied Microscopy
• /
• v.35 no.3
• /
• pp.129-134
• /
• 2005

The cytotoxicity that chemical disinfectants of K products and natural disinfectants of naringin & chitosan well-known preservative, have on endothelium and epithelium of rabbit's cornea were obseved by scanning electron microscope. The main component of naringin is grapefruit seed extract, which is one of the flavonoid widely recognized as natural antioxidants and used as preserved food and cosmetics. The chitosan also wildly distributed epithelium of crustacea, epidermis of insects, mould, fungi and so on. It is no harm of cytotoxicity of human body and recognized of antibacterial for various of bacteria. This study was performed to examine the cytotoxicity of natural and chemical preservative.

• Proceedings of the SAREK Conference
• /
• 2006.06a
• /
• pp.95-98
• /
• 2006

Filtration by fibrous filter is one of the Principle methods used for removing pollutant particles in the liquid. Because of the increasing need to protect both human health and valuable devices from exposure to fine particles, filtration has become more important. Filters have been developed with modified surface charge characteristics to capture and adsorb particles by electrokinetic interaction between the filter surface and particles contained in water. The main purposes of this study are to develop and evaluate the performance evaluation of the apparatus for making a positively charged porous filter media and to analyze the surface characteristics of the filter media for capturing negavitely charged contaminants mainly bacteria and virus from water. The experimental apparatus consists of a mixing tank, a vacuum pumping system, a injection nozzle, a roller press and a controller. The filter media is composed of glass fiber(50-750 nm), cellulose($10-20{\mu}m$) and colloidal charge modifier. The characteristics of filter media is analyzed by SEM(Scanning Electron Microscopy), AFM(Atomic Force Microscopy) and quantified by measuring the zeta potential values.

• The Korean Journal of Zoology
• /
• v.35 no.3
• /
• pp.295-307
• /
• 1992

In order to study the differentiation of the epithelial cells during the development of fetal rat lung tissue, histological changeB in organotypic culture and in vivo were examined. Light microscopy and scanning electron microscopy were used to analvre the histological change in rat lung from the 15th nary of gestation to the 111th nary after birth. In organotypic culture system, the pulmonary epithelial cell differentiation was studied by scanning electron microscopy. The results obtained from this study were as follows. 1. During deveiopment of lung, the glandular stage lasted from the Isth day to the lsth naut of gestation; the canalicular stage from the 17th nay to the 19th naut of gestation; the saccuiar stage from 20th nary to the birth. Alveolar stage was observed at the 3rd nary of postnatal rat lung. 2. In organotvpic culture of fetal rat lung cells organized alveolar-like structures resembling those of in uiuo state were observed on the gelatin matrix. In contrast with in vivo state, fetal lung cells formed group of type ll pneumocytes predominently along the contours of the matrix. These cells have large apical surface, short microvilli and secreted materials which may be sunactant. These results suggested that an orsanotypic culture retaining epithelial- -mesenchvmal relationships is appropriate culture model to study the pulmonary epithelial cell (especially type ll pneumocvte) differentation.

• Korean Journal of Materials Research
• /
• v.32 no.3
• /
• pp.153-160
• /
• 2022

ZnO nanosheets have been used for many devices and antibacterial materials with wide bandgap and high crystallinity. Among the many methods for synthesizing ZnO nanostructures, we report the synthesis of ZnO/Zn(OH)₂ nanosheets using the ionic layer epitaxy method, which is a newly-developed bottom-up technique that allows the shape and thickness of ZnO/Zn(OH)₂ nanosheets to be controlled by temperature and time of synthesis. Results were analyzed by scanning electron microscopy and atomic force microscopy. The physical and chemical information and structural characteristics of ZnO/Zn(OH)2 nanosheets were compared by X-ray photoelectron spectroscopy and X-ray diffraction patterns after various post-treatment processes. The crystallinity of the ZnO/Zn(OH)₂ nanosheets was confirmed using scanning transmission electron microscopy. This study presents details of the control of the size and thickness of synthesized ZnO/Zn(OH)₂ nanosheets with atomic layers.

• Applied Microscopy
• /
• v.15 no.2
• /
• pp.111-129
• /
• 1985

The morphology and histology of the gastrointestinal mucosa of the mole, Talpa micrura coreana (Thomas), were studied using light and scanning electron microscopes. Tissue specimens were taken from body and pyloric portions of the stomach, and from the initial, proximal, middle, distal and terminal portions of the intestine. For light microscopy, tissue blocks were fixed in 10% buffered neutral formalin, embedded in paraffin wax, and sectioned at a thickness of $5{\mu}m$. These sections were stained with hematoxylin-eosin. For scanning electron microscopy, tissue blocks were fixed in 1% glutaraldehyde-1.5% paraformaldehyde, and postfixed in 1% osmium tetroxide, dehydrated in graded alcohol, transferred to isoamylacetate and dried by the critical point drier(Polaron E 3000). Subsequently, specimens were coated with gold and observed with a JSM-35C scanning electron microscope. The results were as follows: The mucous membrane of the body portion of the stomach had numerous irregular folds and the pyloric mucosa formed the strawberry-shaped folds, and general histological structures of each portion were similar to those of man. The intestine could not be differentiated macroscopically and microscopically into small and large intestines. There was no cecum, appendix, taenia coli, haustra coli or appendices epiploicae. In the initial portion (4 mm long), conical or tongue-shaped villi with the height of $143.3{\pm}10.7{\mu}m$ were present, and large mucous glands were seen in the submucosa. In the proximal, middle and distal portions, wavy folds composed of the epithelium and lamina propria were densely and transversely arranged, and their heights were $440.4{\pm}45.5{\mu}m,\;454.4{\pm}19.9{\mu}m\;and\;205.2{\pm}33.5{\mu}m$, respectively. The mucosa of the terminal portion (3 cm long) formed several longitudinal folds, and the intestinal glands were directly opened on the smooth surface of the folds. Aggregated lymphoid follicles were observed in the major portions of the intestine except the initial and terminal portions. There was no circular or semilunar fold throughout the intestine.

• Korean Journal of Veterinary Research
• /
• v.39 no.3
• /
• pp.399-406
• /
• 1999

The development of uterus in fetuses on 60, 90 and 120 days of gastation and neonates of Korean native goats was investigated by scanning electron microscopy. The results were summarized as follows ; 1. In the 60-day-old fetuses, the short microvilli were sporadically observed on the luminal surface of the endometrium. 2. In the 90-day-old fetuses, the mucosal folds, polygonal microridges, numerous microvilli, flower-like-buds, and domeshaped or crateriform area were also observed on the luminal surface of endometrium. 3. In the 120-day-old fetuses, the primordial caruncles(nodules) of the endometrium were developed conspicuously and long microvilli were developed densely. 4. In the neonates, the caruncles and microvilli of the endometrium were more developed than those of 120-day-old fetuses.

• 한국전자현미경학회:학술대회논문집
• /
• 2001.11a
• /
• pp.18-22
• /
• 2001

A technique to characterize specific site of materials using a combination of a dedicated focused ion beam system(FIB), and Intermediate-voltage scanning transmission electron microscope(STEM) or transmission electron microscope(TEM) equipped with a scanning electron microscope(SEM) unit has been developed. The FIB system is used for preparation of electron transparent thin samples, while STEM or TEM is used for localization of a specific site to be milled in the FIB system. An FIB-STEM(TEM) compatible sample holder has been developed to facilitate thin sample preparation with high positional accuracy Positional accuracy of $0.1{\mu}m$ or better can be achieved by the technique. In addition, an FIB micro-sampling technique has been developed to extract a small sample directly from a bulk sample in a FIB system These newly developed techniques were applied for the analysis of specific failure in Si devices and also for characterization of a specific precipitate In a metal sample.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.23 no.5
• /
• pp.235-240
• /
• 2013

Pure-carbon materials such as graphite, graphene, carbon nanotubes, and diamond have very high thermal conductivities. The reported thermal conductivity of graphene is in the range 3000~5000W/m-K at room temperature. Here, we developed graphene/cu foam hybrid type heat spreader to obtain higher thermal conductivity than Cu foam. Hybrid materials were characterized using optical microscopy (OM), scanning electron microscopy (SEM) and thermal conductivity measurement system; LFA (Laser Flash Analysis @ LFA 447, NETZSCH). We suggest that excellent thermal properties of graphene/cu foam hybrid structures are beneficial for all proposed electrical applications and can lead to a thermal management application.