• Journal of Aquaculture
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• v.13 no.3
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• pp.215-222
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• 2000

The primordial germ cell of the sweet fish was recognized from the 2-day old fry (tl : 0.66 cm), when it began to protrude into peritoneal cavity between meaonephric duct and gut. The primordial gonad, with the formation of genital ridge, developed on the 30-day old fry. Ovarian differentiation was identified by the presence of ovarian cavity and meiotic oocytes from the 90-day old fry (tl : 3.42 cm). Testicular differentiation was identified by the presence of spermatogonial cells with efferent duct from the 100-day old fry (11 : 4.50 cm). Hence the sweet fish belongs to the differentiated type of gonochoristic teleost.

• Journal of Aquaculture
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• v.18 no.2
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• pp.76-80
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• 2005

The early gonadal development and sex differentiation of the mandarin fish, Siniperca scherzeri was described from hatch to the 130th day post-hatch (DPH). Primordial germ cells were observed on the just hatched fry (5.10 mm in total length (TL)) and began to protrude into the peritoneal cavity between mesonephric duct and gut. The primordial gonad, with the formation of genital ridge, developed on the 8-10th DPH (10.77-12.47 mm TL). Ovarian differentiation was identified by the presence of ovarian cavity and meiotic oocytes from the 40th DPH (29.75 mm TL). Testicular differentiation was identified by the presence of spermatogonial cells with efferent duct also from the 40th DPH. Sex differentiation of the mandarin fish was identified as gonochoristic type.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.35 no.4
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• pp.98-109
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• 2017

The results of this study attempting to graft to the space by cognizing and categorizing the characteristic of the under-toned private property to the tablets of the Zhuozhengyuan are as follows. The tablet of Zhuozhengyuan was typed into three groups. In the A group, the frequency of artificial elements including the top, ship, and head was high, and the main emphasis was on the elegance and integrity spirit that the Sunbi(classical scholar) had to have. It has a characteristic of good architects such as pavilion and Nu(樓) is included and as it is adjacent to the water surface the one side of the building is integrated to the water surface. The B group is characterized mainly by the fact that the scenery is portrayed through the climatic factors including rain, wind, and snow, or the scene atmosphere and it is located at the top of the summit which is good for viewing the scenery. In the C group, plant elements such as lotus, magnolia, plum, and bamboo appeared frequently, and various buildings such as pavilion, Kwan(館), Gak(閣) and Dang(堂) belong to this structure. The structure has the characteristic of integrating directly with the water surface or putting the terrace between and scattering throughout the whole garden. Furthermore, this study identified area characteristics based on the frequency of the tablet type. In the west area, Group A is mostly distributed and the humor and concept implied in the tablet, combined with the shape and location of the scenery, viewpoint of the viewer, and the composition of the landscape, improved the orderliness of the space, which led to expand the scope of the enjoyment to the entire space. Meanwhile, in the middle area, tablets of Group C are mostly distributed, and the unique characteristics and shapes of the woody plants that were used as the name of the tablet were connected with various buildings including pavilion, Dang, Kuan, and Gak, improving the unique identity of the space and forming connection with the world of ideas through unity and independence.

• Applied Microscopy
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• v.33 no.1
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• pp.25-39
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• 2003

Cell differentiation and ultrastructural characteristics in the seminiferous epithelium of Myotis macrodactylus was investigated with the light and electron microscopes. Spermatogenesis has begun at April and finished at September. The nuclei of A spermatogonia (dark and pale type of spermatogonia) were oval, applied to the basal lamina, and surrounded by Sertoli cells. By comparison with other types of spermatogonia, the cell and nucleus of B type of spermatogonium is globular and larger than A types of spermatogonia. The nucleolus appears as a coarse and touches the nuclear membrane. The cell and nucleus of spermatocytes was globular and larger, but primary spematocyte is larger than secondary spermatocyte. Spermiogenesis was divided according to the level of fine structural difference, into Golgi, cap, acrosomal, maturation and spermiation phases; Golgi, cap, acrosomal and spermiation phases were further subdivided into steps of early and late phase respectively, and maturation phase has only one step. Hence, the spermiogenesis has been divided into a total of nine phases. In the change of karyoplasm, the chromatin granules are condensed at late Golgi phase and completed at spermiation phase. The sperm tail began to develop in early Golgi phase and completed in spermiation phase. The process of degeneration of spermatogenic cells in the seminiferous tubules was continually observed from October, before the beginning of hibernation, to hibernation phase (November, December, January, February, March). Immatured spermatogenic cells in the seminiferous tubules have been engulfed by phagocytosis of Sertoli cells during period of degeneration. It is deduced that the adaptative strategy serves as the mechanism to regulate the effective use of energy to prepare for long hibernation and regulation of breeding cycle.

• Applied Microscopy
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• v.38 no.3
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• pp.205-212
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• 2008

In this study morphological changes of the testes of golden hamsters treated with 6-aminonicotinamide (6-AN, 10 mg/kg body weight) in every two days were investigated using light and transmission electron microscopes. After the 7th injection of 6-AN, body weights of hamsters were significantly reduced, and the weight of testes were markedly reduced in the group of hamsters after 5th injections. Degeneration of seminiferous epithelium appeared first in the group receiving 5th injections, which were followed by severe degenerations after the 9th injection. In the degenerated seminiferous epithelium, deep vacuolization, and destruction of spermatogenic cells and Sertoli cells were also oberved. Multinuclear giant cells were also observed in the lumen of destructed seminiferous epithelium. But there were no edematous changes in the interstitial tissue, and the Leydig cells were found to be relatively intact. Therefore, these results show that 6-AN trigger severe morphological alteration of the spermatogenic cells and Sertoli cells, however Leydig cells are unaltered by 6-AN.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.547-552
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• 2003

Separation and determinations of Co(II) and Ni(II) ions as their 4-(2-pyridylazo)resorcinol(PAR) chelates by reversed-phase capillary high-performance liquid chromatography(RP-CpHPLC) were performed. Among many capillary columns, Vydac C4 column was selected and acetonitrile solution was used as mobile phase. The effect of pH and MeCN concentration(%) on the retention factor, k and peak intensity was examined and discussed. As a results, it was found that 22.5% MeCN and pH 5.60 was adequate as mobile phase for the separation of the two metal ions and determination of Co(II) ion, but the mobile phase condition for Ni(II) ion determination was 22.5% MeCN of pH 7.20. Detection limit(D.L., S/N=3) of Co(II) and Ni(II) ions were $2.0{\times}10{-7}$ M(14.9 ppb) and $1.0{\times}10{-6}$ M(59.2 ppb), respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.299-304
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• 1983

It has been ascertained by a few researchers that soil conditions under which the rice plants were cultivated have some effects upon the root formation of the rice plants. But, much is not known about the root formation of the rice plants cultivated in the saline paddy fields. The goal of the present investigation is to study morphological effects of the soil salinity on the development of the rice root system. The following results were obtained: 1. Under the conditions of higher soil salinity, root systems developed well at surface soil, however, root systems developed well and distributed evenly through surface and sub-soil at the saline fields where soil salinity was lower. 2. The rice plants cultivated in the higher soil salinity form less crown roots than the rice plants which cultivated at the lower soil salinity. 3. As for the formation of the stunted roots, it was found out that relatively rice plant cultivated in higher soil salinity forms more stunted roots than the rice plants cultivated in lower soil salinity. 4. The crown root cultivated in the higher soil salinity forms more lateral roots per unit langth than the root cultivated in lower soil salinity. 5. As for the root hair formation, the crown root cultivated in higher soil salinity bears less haired epidermis and shorter root hairs than the root cultivated in lower soil salinity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2859-2865
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• 2011

The welded connection is known as an essential factor for establishing qualified construction and/or maintenance of wrapped steel pipe. In this study, welded connection conditions in the coated pipes with large diameter (over 700 mm) in Korea water distribution systems were estimated for suggesting technically and economically available welded connection method. For the study analysis, current steel pipe usage and accident cases were investigated. In addition, the characteristics of each welded connection method and automatic or manual connection techniques were also compared and estimated. As results, automatic welded connection method is superior than manual welded connection method in aspect of pure construction cost (average 9%) or pure welded connection cost (average 13.5%). When the poor welding-working situations in Korea are considered such as high tolerance of out-of-roundness in KS regulation, a number of lap joint welded connections, the real cost benefits of automatic welded connection should be much higher than those of manual welded connections.

• Korean Journal of Heritage: History & Science
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• v.57 no.3
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• pp.116-137
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• 2024

This study quantitatively explored the interrelationship between water features and surrounding waterscape elements through a literature review and observational study targeting nine waterscapes of Suzhou Classical Garden in Jiangsu Province, China, which is designated as a UNESCO World Heritage Site. The purpose was to understand the objective characteristics of classical Chinese gardens and seek a basis for their differences from Korean gardens. The average area of water space in Suzhou gardens was 1,680.7㎡, which accounted for 21.3% of the total garden area, showing large variation by garden. Most of the Suzhou Gardens use springs and wells as their water sources. The Surging Waves Pavillion uses surface water, and Retreat & Reflection Garden uses seasonal water as its water source. The water pipes in Suzhou Garden are divided into a water outlet and a water outlet(water holes). Of these, the water outlet is a water outlet that imitates the water outlet just to induce a visual effect, and focuses on the meaning of the water system. It is judged to have been combined with the trend of Suzhou gardens. In addition, it was confirmed that, semantically, the arrangement of the water polo in Suzhou Garden is based on the traditional 'Gamyeo(堪輿) theory'. Meanwhile, there are five types of methods for bringing water to Suzhou Garden: Jiginbeop(直引法), Myeonggeobeop(明渠法), Invasionbeop(滲透法), Gwandobeop(管道法), and Chakjeongbeop(鑿井法). Suzhou Classical Garden mainly applies the infiltration method and the irrigation method as a method of securing water in the garden, which can be classified and defined as the water catchment method(集水法) and the water pulling method(引水法) in the domestic classification method. Among the watering techniques in Korean traditional gardens, watering methods such as 'suspension waterfall(懸瀑)', 'flying waterfall(飛瀑)' and water eluted(湧出), have not been found, and it is believed that they mainly 'rely on hide with dignity(姿逸)' and 'submerged current(潛流)' techniques. As for the watering technique, no watering technique was found that uses a Muneomi, which is applied in traditional Korean gardens. As this was applied, the seal method, penetration method, and Gwandobeop were also used in water extraction techniques. And at the inlet and outlet of Suzhou Garden, the main static water bodies were lakes, swamps, and dams. While the eastern water bodies are classified into streams, waterfalls, and springs, the water spaces in the three gardens reflect the centrifugal distributed arrangement, and the water spaces in the six places reflect the water landscape effect due to the centripetal concentrated arrangement. And as a water space landscape design technique, the techniques of 'Gyeok(隔)' and 'Pa(破)' were mainly applied at the inlet, and the techniques of 'Eom(隔)' and 'Pa(破)' were mainly applied at the outlet. For example, most bridges were built around the inlet, and sa(榭), heon(軒), gak(閣), pavilion(亭), and corridor(廊) were built, and the outlet was concealed with a stone wall. Therefore, it is understood to have embodied Suzhou Garden's idea of water(理水), which says, "Although it was created by humans, it is as if the sky is mine(雖由人作，宛自天開)."A trend was detected. Lastly, as a result of analyzing the degree of concealment and exposure in the visual composition of the inlet and outlet, it was confirmed that the water outlet was exposed only at the Eobijeong and Mountain Villa with Embracing Beauty view points of The Surging Waves Pavillion and the water outlet was hidden at other view points. Looking at these results, the 'Hyang-Hyang-Ba-Mi-Bob(向向發微法)' from the perspective of left-orientation theory of Feng Shui, which is applied in Korean traditional gardens in classical Chinese garden water management, "makes water visible as it comes in, but invisible as it goes out." It is judged that the technique was barely matched.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.313-320
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• 2013

Biofilm formed on stainless and copper in water treatment plant was investigated for sixteen weeks. Biofilm reactor was specially designed for this study. It was similar to that of a real distribution pipe. Raw water, coagulated, settled, filtered and treated water were used in this study. The average number of heterotrophic bacteria counts was $1.6{\times}10^4CFU/ml$, $5.8{\times}10^3CFU/ml$, $1.8{\times}10^3CFU/ml$, $1.3{\times}10^2CFU/ml$, 1 CFU/ml, respectively. Density of biofilm bacteria formed on stainless and copper pipes in raw, coagulated and settled water increased above $2.9{\times}10^3CFU/cm^2$ within second weeks while more biofilm bacteria counts were found on the stainless pipe than on the copper pipe. In case of filtered water (free residue chlorine 0.44 mg/L), there was no significant difference in the number of biofilm bacteria on both pipes and biofilm bacteria below $18CFU/cm^2$ were detected on both pipe materials after fifth weeks. Biofilm bacteria were not detected on both pipe materials in treated water (free residue chlorine 0.88 mg/L). According to the results of DGGE analysis, Sphingomonadacae was a dominant species of biofilm bacteria formed on the stainless pipe while the copper pipe had Bradyrhizobiaceae and Sphingomonadaceae as dominant bands. In case of filtered water, a few bands (similar to Propionibacterium sp., Sphingomonas sp., Escherichia sp., and etc.) that have 16S rRNA sequences were detected in biofilm bacteria formed on both pipes after fifth weeks. Stainless pipe had higher species richness and diversity than the copper pipe.