• Corrosion Science and Technology
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• v.9 no.6
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• pp.331-337
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• 2010

This study compared the macro and micro electrochemical characteristics at the local area of welding metal on dissimilar welding parts for type 304 stainless steel (SS) and type 316L SS. The materials are used for double wall gas pipe of duel fuel engine for a ship. The various potentiodynamic experiments were performed several times in 10% ${H_2C_2O_2}{\cdot}{H_2O}$ solution using macro and micro methods, respectively. The micro electrochemical experiments conducted to resolve at local area on cross-section of dissimilar welding materials by micro-droplet cell device. The micro-droplet cell techniques can be used almost electrochemical experiments to resolve corrosion characteristics of the limited electrode area of the metallic surface between wetted spot of working electrode and tip of sharpened capillary tube. The results of macro electrochemical experiments show that resistance of active dissolution reaction at welding zone was high due to low current density by formation of passivation protection film at passive region. According to the micro electrochemical experiment, the corrosion current density of welding zone and bond zone were relatively high.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.1
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• pp.65-71
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• 2016

Injection rate, injection quantity and injection timing of fuel are controlled precisely by electric control in CRDI system. Particularly, injection rate being influenced with injection pressure affects to spray characteristics and fuel-air ratio, so it is a very important factor in diesel combustion. In this study, injection rates in accordance with injection pressure at a constant ambient pressure were measured with Zeuch's method. Under the same condition, non-evaporating spray images were taken with a high speed camera and analyzed carefully with Adobe Photoshop CS3. Macroscopic spray characteristics and breakup processes in the spray could be found from the examined and analyzed data. Injection start time and injection period were practically affected with injection pressure. Also, initial injection rate, spray penetration, spray angle and breakup of high density droplets region in the spray were affected with injection pressure. The results and techniques of spray visualization and injection rate measurement in this study would be practically effective to study a high pressure diesel spray for common rail direct injection system.

• Applied Microscopy
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• v.35 no.2
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• pp.89-96
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• 2005

The ultrastructures of the fertilized egg envelope from Hyphessobrycon serpae belonging to Characidae was studied using scanning and transmission electron microscopes to get systematic fundamental data for classification of species and to confirm whether micropyle is a common trait of Characidae or not. The fertilized egg was of colorless, transparent, spherical, adhesive and demersal type. There were not oil droplets in vitelline membrane and attached structures in the outside of fertilize egg envelope. The egg envelope had a single micropyle resembling the pathway of sperm in the area of the animal pole. The micropyle was surrounded by 13 to 15 protruded lines of the egg envelope in a radiated form. The outer surface of fertilized egg envelope was covered by reticular adhesive fibrous structures and irregularly arranged by pore canals. The fertilized egg envelope consisted of three distinct layers an outer adhesive fibrous layer with high electron density, a middle layer with pore canals, and an inner layer consisting of 6 to 7 lamellae alternating layers with interlamellae of lower electron density. These ultrastructural characters of fertilized egg envelope form Hyphessobrycon serpae can be utilized in taxonomy of teleost, and as fundamental data for study on early development of fertilized egg. It seems that the morphology of micropyle is a common trait of Characidae

• Applied Microscopy
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• v.29 no.3
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• pp.343-351
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• 1999

The structures of the fertilized egg envelope from three species, three-spot gourami (Trichogaster trichopterus), pearl gourami (Trichogaster leeri) and marble gourami (Trichogaster trichopterus trichopterus) belong to Belontiidae were observed, utilizing light, scanning and transmission electron microscopes. In all three species, the fertilized eggs were the colorless, transparent, spherical, adhesive and pelagic type. A large oil droplet was located in vitelline membrane of the fertilized egg. The egg envelopes have a single micropyle, which is thought to the pathway of sperm in the area of the animal pole. Specially, the micropyle of three-spot gourami was similar to that of marble gourami which is subspecies of three-spot gourami. An outer surface of the fertilized egg envelope was arranged by grooves in all three species. The fertilized egg envelopes consists of two distinct layers; an adhesive outer layer and an inner layer with high electron density. In conclusion, the morphological similarity of the fertilized egg, micropyle, outer surface and transverse section of the fertilized e9g envelope seems to be an indication of the Belontiidae.

• The Journal of Korean Obstetrics and Gynecology
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• v.27 no.1
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• pp.41-64
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• 2014

Objectives: This study was to evaluate the effect of Jaeumkanghwa-tang (JEKHT) on the propylthiouracil (PTU)-induced rat hypothyroidism. Methods: Six groups, each of 8 rats per group were used in the present study - intact vehicle control, PTU control, Levothyroxine ($LT_4$), JEKHT 500, 250 and 125 mg/kg treated groups. JEKHT were administered once a day for 42 days as an oral dose of 500, 250 and 125 mg/kg, and hypothyroidism was induced by daily subcutaneous treatment of PTU 10 mg/kg for 28 days. The changes on the body and organ weight, serum hormone and lipid profiles, liver and testis antioxidant defense factors were observed with histopathology of organs. Results were compared with $LT_4$ 0.5 mg/kg intraperitoneally treated rats in this experiment. Results: PTU treatment, marked decrease of body weight, increases of thyroid weight, decreases of liver, testis, epididymis and prostate weights, decreases of serum Tri-iodothyronine ($T_3$), and Thyroxine ($T_4$) level with increase of serum Thyroid-stimulating hormone (TSH) level, decreases of serum testosterone and dihydrotestosterone (DHT) level with increases of serum Follicular stimulating hormone (FSH) level, increases of serum High density lipoprotein (HDL), decrease of triglyceride content, increase of serum Aspartate aminotransferase (AST) level, decreases of liver and testis antioxidant defense factors were observed. In addition, marked hyperplasia of follicular cells with decreases of follicular colloid contents and diameters was additionally demonstrated with the decrease of hepatocyte numbers per unit area due to hypertrophy of hepatocytes related to lipid droplet depositions, increase of a/oligospermatic epididymal tubules with epididymal atrophic changes, seminiferous tubular atrophy with decrease of stage I~II seminiferous tubules in testis, prostate tubular atrophic changes at histopathological inspections. However, these PTU induced hypothyroidism and related hepatic and male reproductive organ damages were favorably and dose-dependently inhibited by treatment of JEKHT 500, 250 and 125 mg/kg, and JEKHT also effectively regulated the PTU-induced abnormal antioxidant defense factor changes in the both liver and testis. Conclusions: JEKHT 500, 250 and 125 mg/kg dose-dependently inhibited PTU-induced hypothyroidism and related liver and male reproductive organ damages in rats.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.950-955
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• 2007

Non-point source control system which had been designed only for oil-water separation in the fields of oil refinery and garage was upgraded in this research for the removal of runoff pollutants in impervious urban area. Pollutants including oil from driveway and bridge were eliminated by two types of pathway in the system. One is the coalescence mechanism that the oil droplets in the runoff come into contact with each other in the spiral buoyant media surface and form larger coalesced droplets of oil that are carried upstream to the oil layer. The other is the precipitation that solids in runoff were settled by gravity in the system. In this research, coalescing characteristics of oil and water separation were investigated through image analyses, and efficiencies of the non-point source control system were evaluated using dust in driveway and waste engine oil. Media made of high density and high molecular weight polyethylene was indeterminate helical shape and had sleek surface by analysing SEM photographs and BET. Surface area and specific gravity of media which were measured directly were 1,428 $mm^2$ and 45.3 $kg/m^3$ respectively. From the image analyses of the oil droplets photographs which were taken by using microscope, it was proved clearly that the coalescence was the main pathway in the removal of oil from the runoff. Finally, the performances of the non-point source control system filled up with the media were suspended solid $86.6\sim95.2%$, $COD_{Cr}$, $87.3\sim95.4%$, n-Hexane extractable materials $71.8\sim94.8%$ respectively.