• 한국농공학회지
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• 제8권1호
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• pp.1011-1034
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• 1966

This thesis is the final report which has long been studied by the author to obtain the design basis for various hydrological constructions with the specific system suitable to the natural environmental conditions in Korea. This report is divided into two parts: one is to estimate runoff volume from watersheds and the other to estimate the peak discharge for a single storm. According to the result of observed runoff record from watersheds, it is known that Kajiyama formula is useful instrument in estimating runoff volume from watersheds in this country. But it has been found that this formula shows us 20-30% less than the actual flow. Therefore, when wihed to bring a better result, the watershed characteristics coefficient in this formula, that is, f-value, should be corrected to 0.5-0.8. As for the method to estimate peak discharge from drainage basin, the author proposes to classify it in two ways; one is small size watershed and the other large size watershed. The maximum -flood discharge rate $Q_p$ and time to peak Pt obtained from the observed record on the small size watershed are compared by various methods and formulas which are based upon the modern hydrological knowledge. But it was fou.d that it. was not a satisfied result. Therefore, the author proposes. tocomputate $Q_p$, to present 4.0-5.0% for the total runoff volume ${\Sigma}Q$.${\Sigma}Q$ is computed under the assumption of 30mm 103s in watershed per day and to change the theoritical total flow volume to one hour dura tion total flow rate when design daily storm is given. Time to peak Pt is derived from three parameters which are u,w,k. These are computed by relationship between total runoff volume (ha-m unit)and $Q_p$. (C.M.S. unit). Finally, the author checked out these results obtained from 51 hydrographs and got a satisfied result. Therefore the author suggested the model of design dimensionless unit-hydrograph. And the author believes that this model will be much available at none runoff record river site. In the large size watersheds in Korea when the maximum discharge occurs, the effective rainfall is two consequtive stormy days. So the loss in watershed was assutned as 6Omm/2days,and the author proposed 3-hour-daration hydrograph flow distribution percentage. This distribution percentage will be sure to form the hydrograph coordinate.

• 한국전기전자재료학회논문지
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• 제27권12호
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• pp.803-808
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• 2014

$Bi_{0.5+x}(Na_{0.78}K_{0.22})_{0.5-3x}TiO_3$ ceramics with an excess $Bi^{3+}$ and a deficiency of $Na^+$ and $K^+$ were synthesized by a conventional solid state reaction method. The structure and morphology of $Bi_{0.5+x}(Na_{0.78}K_{0.22})_{0.5-3x}TiO_3$ ceramics were characterized by X-ray diffraction and field emission scanning electron microscopy. The electric polarization and mechanical strain induced by external electric field, and the temperature dependence of dielectric constant were investigated. These results demonstrated that an ergodic relaxor phase can be induced by controls of the mole ratio of $Bi^{3+}$, $Na^+$ and $K^+$. A phase boundary between non-ergodic and ergodic relaxor phases can be observed at ambient temperature. The ergodic relaxor phase can be transferred to the ferroelectric phase by application of the electric field. The stability of the induced ferroelectric phases strongly depends on the mole ratio of $Bi^{3+}$, $Na^+$ and $K^+$. The maximum strain of 0.31% was observed in $Bi_{0.51}(Na_{0.78}K_{0.22})_{0.47}TiO_3$ ceramics sintered at $1,150^{\circ}C$ for 2 h.

• 한국토양비료학회지
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• 제3권1호
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• pp.61-66
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• 1970

홍적(洪積)에 기인(基因)된 적황색토중(赤黃色土中) 생성년대(生成年代)가 오래다고 추정(推定)되는 창평통(昌平統)에 대한 형태(形態) 및 물리적(物理的) 화학적(化學的) 성질(性質)에 관(關)하여 조사(調査)한 결과(結果)를 요약(要約)하여 보면 다음과 같다. 형태적특성(形態的特性)에 있어 표토(表土)(A층(層))는 암갈색(暗褐色)의 미사질식양토(微砂質埴壤土)이며 심토(心土)(B층(層))는 암적색(暗赤色) 내지(乃至) 적색(赤色)의 미사질식토(微砂質埴土) 혹은 식토(埴土)로서 토괴표면(土塊表面)에 점토피막(粘土皮膜)이 형성(形成)되어 있다. 기층(基層)은 풍화(風化)된 석력(石礫)이 있는 홍적모재(洪積母材)이며 토양(土壤)의 깊이는 150cm 이상(以上)으로 매우 깊다. 물리적(物理的) 화학적(化學的) 특성(特性)에 있어서는 강산성(强酸性)(표토(表土) 4.5 심토(心土) 5.2~5.5)이며 유기물함량(有機物含量)(표토(表土) 0.84% 심토(心土) 0.15~0.8%)이 낮음과 동시(同時) 염기치환용량(鹽基置換容量)(표토(表土) 12me/100g 심토(心土) 8.9~23.5me/100g)도 낮다. 그러나 치환침출염류(置換浸出鹽類) 총량(總量)에 의(依)한 염기포화도(鹽基飽和度)(표토(表土) 55% 심토(心土) 48~85%)는 비교적(比較的) 높은 편(便)이다. 토양입자(土壤粒子)의 수직분포(垂直分布)에 있어서 표토(表土) 및 심토(心土)는 뚜렷한 변화(變化)가 없는 것으로 보아 심토(心土)에 있어 점토집적(粘土集積)은 Podzolization에 의(依)한 것이라기 보다 점토(粘土)의 기계적이동(機械的移動)에 의(依)한 것이라 추정(推定)된다. 창평통(昌平統)은 USDA 7차분류시안(次分類試案)에 의(依)하면 Typic Hapludalfs, FAO 분류방식(分類方式)에 의(依)하면 Brunic Luvisols 에 속(屬)한다.

• 한국약용작물학회지
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• 제21권5호
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• pp.361-371
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• 2013

This study was performed to determine the antimelanogenic effect and tyrosinase inhibitory activities of anthocyanin rich fraction (AN-SLP) from Liriope platyphylla Wang et Tang seeds. Anthocyanins isolated from L. platyphylla seeds revealed the presence of four major anthocyanin components, which were tentatively identified as delphinidin-3-Oglucoside, delphinidin-3-O-rutinoside, petunidin-3-O-rutinoside, and malvidin-3-O-rutinoside using semipreparative HPLC, $^1H$-NMR, $^{13}C$ NMR, FAB-MS and LC/ES-MS. The inhibitory effect of AN-SLP on tyrosinase activity was studied using in vitro (against mushroom tyrosinase) and ex vivo (against B16 melanoma cell tyrosinase) models. Cellular tyrosinase activity was decreased by AN-SLP treatment in B 16 melanoma cells through dose dependent manner, but AN-SLP did not inhibit mushroom tyrosinase and L-DOPA oxidation directly. AN-SLP showed melanin inhibition by 53.2% at 50 ${\mu}g/m{\ell}$ which was 0.7 times more efficient than the antimelanogenic effect of commercial arbutin and kojic acid (36.5%) also did not show cell toxicity. Additionally, AN-SLP inhibited the activity of ${\alpha}$-glucosidase and the glycosylation of tyrosinase in melanoma cell. The resulting unsaturated glycosylation of tyrosinase makes it unstable and disturb correct transportation. From theses results, we conclude that AN-SLP could be used as anti-melanogenic agent for skin whitening.

• 한국균학회지
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• 제23권1호통권72호
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• pp.61-70
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• 1995

Armillaria 속균은 천마를 생산하는데 아주 중요한 균이다. 한국에서는 천마재배지의 골목과 이병수목 그리고 그 곳에서 발생한 자실체로부터 72균주가 분리 되었다. 이들 분리균에 대한 정확한 biological species를 분류하기 위하여 tester를 이용하여 교배시험을 한 결과 A. mellea가 2균주로 이들 균주는 천마재배포장에서 분리 된 균주이며 이제까지 채집한 자실체에서 분리된 균주에서는 A. mellea가 없었다. A. tabescens는 7균주로 치악산에서는 신나무, 속초에서는 해송의 그루터기와 강원대 연습림의 참나무에서 형성된 자실체에서 분리되었으며 A. ostoyae는 24균주로 주로 본 병원균에 침입을 받아 죽은 10년생 전후의 잣나무의 지표면 부위에 형성된 자실체에서 분리되었다. A. gallica는 39균주로 주로 참나무 등 14 종류의 기주식물 그루터기에 형성된 자실체에서 분리되었다. Armillaria 속균들은 배양적 특성에 따라서 4가지 Group 들로 분리되었으며 Group II인 KNU-A110(A. gallica)은 다른 Group들에 비해 균사의 생장과 균사속 형성이 대단히 왕성하였고 천마의 생산에도 우수한 것으로 판별되었다. 이 균들은 식물조직에 있는 mycelial fan과 천마 사이를 균사속에 의하여 연결하고 있다. 또한 재배 방법에 있어서는 종균접착법이 가장 좋았다. 천마는 강원도 내의 13개 지역에서 발견되었다. 천마는 줄기의 색에 의하여 3가지 종류로 구별되었으며 줄기색이 brownish orange와 greyish yellow는 G. elata로 판별되었고 줄기색이 greyish green 인 것은 G. gracilis로 판별되었다. 천마는 주로 5월 중순에서 6월 중순 사이에 낙엽이 덮여진 부식토층의 남향 경사지에서 채집되었다. 자마는 성숙한 천마가 싹이나고 썩으며 생산되든지 다른 자마로부터 출아로 생산되었다. 자마는 균사속으로부터 영양분을 얻어서 자라게 되며 자마가 성숙한 천마가 되기까지는 약 3년이 소요된다.

• 한국재료학회지
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• 제21권7호
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• pp.384-390
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• 2011

Ti-6Al-4V ELI (Extra Low Interstitial) alloy has been widely used as an alternative to bone due to its excellent biocompatibility. However, it still has many problems, including a high elastic modulus and toxicity. Therefore, nontoxic biomaterials with a low elastic modulus should be developed. However, the fabrication of a uniform coating is challenging. Moreover, the coating layer on Ti and Ti alloy substrates can be peeled off after implantation. To overcome these problems, it is necessary to produce bulk Ti and Ti alloy with hydroxyapatite (HA) composites. In this study, Ti, Nb, and Zr powders, which are biocompatible elements, were milled in a mixing machine (24h) and by planetary mechanical ball milling (1h, 4h, and 6h), respectively. Ti-35%Nb-7%Zr and Ti-35%Nb-7%Zr-10%HA composites were fabricated by spark plasma sintering (SPS) at $1000^{\circ}C$ under 70MPa using mixed and milled powders. The effects of HA addition and milling time on the biocompatibility and physical and mechanical properties of the Ti-35%Nb-7%Zr-(10%HA) alloys have been investigated. $Ti_2O$, CaO, $CaTiO_3$, and $Ti_xP_y$ phases were formed by chemical reaction during sintering. Vickers hardness of the sintered composites increases with increased milling time and by the addition of HA. The biocompatibilty of the HA added Ti-Nb-Zr alloys was improved, but the sintering ability was decreased.

• 동의생리병리학회지
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• 제20권6호
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• pp.1497-1501
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• 2006

The therapeutic anti-diabetic effect of Nelumbo Folium and a poly herbal formula (NOC) was evaluated in the streptozotocin (STZ 60 mg/kg, I.p.) induced diabetic rats. For this study, test articles were orally administrated once a day from 7 d after STZ-injection for 3 weeks. The fasting blood glucose, body weight, pancreas weight changes, oral glucose tolerance test, hemoglobin Alc (Hb A1c) level changes and the histopathological changes were observed. WNL-treated rat had lower fasting blood glucose levels compared to control group and NOC-treated rat had significantly lower fasting blood glucose levels, compared to control group (p < 0.05). After 21 days of extract treatment, body weight in control was reduced (p < 0.001). WNL and NOC groups were also reduced compared to control group but insignificantly. Pancreas weight of control group was reduced (p < 0.001), but the weight of NOC group were increased (P< 0.05). During the 2 h oral glucose tolerance test (OGTT), WNL group were improved compared to control group (P < 0.05). NOC group were improved compared to control group but insignificantly. WNL and NOC groups had lower Hb Alc level compared to control group. In addition, atrophy of islet and decrease of insulin-producing cells were detected in STZ induced diabetes rats. However, these diabetic changes were decreased in WNL and NOC groups. These results suggest that N. Folium and NOC have favorable effects to inhibit the changes on the fasting blood glucose levels, pancreas weight, glucose tolerance, hemoglobin Alc and the histopathological changes of pancreas in STZ-induced diabetes.

• Parasites, Hosts and Diseases
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• 제57권6호
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• pp.657-664
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• 2019

We identified the echinostome metacercariae in Chinese mystery snails, Cipangopaludina chinensis malleata, from Xiengkhuang Province, Lao PDR with morphologies of adult worms recovered. Total 20 snails were examined with artificial digestion method and then the collected metacercariae were orally infected to a mouse and a rat. Adult worms recovered from experimental animals were observed with a light microscope and a SEM. The metacercariae were round, 125×123 ㎛ in average size, with a moderately thick cyst wall, collar spines distributed in the head collar and excretory granules in 2 canals of excretory tube. Adult flukes (3-week-old in a rat) were elongated, ventrally curved and 5.310×1.023 mm in average size. Head collar distinct, bearing 43 collar spines with 5 end group ones on each side. Oral sucker subterminal, prepharynx very short, pharynx well developed, and esophagus relatively short. Cirrus sac well developed, with a saccular seminal vesicle, and ventral sucker very large. Ovary round and on the median line of the body. Testes tandom and elongated. Eggs operculated, elliptical and 90×57 ㎛ in average size. In the SEM observation, the head crown prominent, with 43 collar spines resembled with horns of younger stag. Scale-like tegumental spines were densely distributed on the surface between the head collar and ventral sucker, and their densities were decreased posteriorly. Conclusively, the metacercariae detected in C. chinensis malleata from Lao PDR were identified as those of Echinostoma macrorchis based on the morphological characteristics of adult worms.

• 원예과학기술지
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• 제31권1호
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• pp.24-31
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• 2013

This study was conducted to determine the characteristics of quality and yield in potatoes grown at paddy field before rice transplantation during the spring season. Three potato cultivars ('Jowon', 'Haryeong', and 'Goun') were grown in Gangneung (asl 5 m) and Seocheon (asl 20 m). In both locations, weather condition belonged to the fourth zone (spring cropping) in potato production location's distribution of Korea. Daily mean soil temperature in both the locations was $0.2-0.6^{\circ}C$ lower than air temperature, while soil moisture was adequate level to potato growth in spite of spring drought. TR ratio was not affected by location, but by cultivar. Specific gravity, starch content, dry matter rate, and yield were significantly influenced by location and by cultivar. There was no difference in total tuber number by location, however there was a large gap in marketable tuber yield according to locations and cultivars. There were high negative relationships between yield and main qualities such as dry matter rate and starch content, while high positive correlation was observed between main qualities. It was possible to produce potato before rice transplanting at drained paddy fields located in representative two locations of potato spring cropping and their characteristics in growth and quality were similar to those generally well known in upland cultivation. Paddy field was thought to be more favorable than upland in terms of available soil moisture supply against spring drought. Further research, however, was needed to increase soil temperature and also preliminary review on proper cultivar according to location seemed to be needed for high yield.

• 보건행정학회지
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• 제17권3호
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• pp.87-105
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• 2007

The purpose of this study was to analyze whether nonemergency, isolated coronary artery bypass graft (CABG) surgery for high- or low-risk patients biases the assessment of the risk-adjusted mortality rates of hospitals. This study used 2002 National Health Insurance claims data for tertiary hospitals in Korea. The study sample consisted of 1,959 patients from 23 tertiary hospitals. The risk-adjustment model used the patients' biological, admission, and comorbidity data identified in the claims. The subjects were classified into high- and low-risk groups based on predicted surgical risk. The crude mortality rates and risk-adjusted mortality rates for low-risk, high-risk, and all patients in a hospital were compared based on the rank and the four intervals defined by quartile. Also, the crude mortality rates of the three groups were compared with their 95% confidence intervals of predicted mortality rates. The C-statistic (0.83) and Hosmer-Lemeshow test ($X^2$=11.47, p=0.18) indicated that the risk-adjustment model performed well. Presenting crude mortality rates with their 95% confidence intervals of predicted rates showed higher agreements among the three groups than using the rank or intervals of mortality rates defined by quartile in the hospital performance assessment. The crude mortality rates for the low-risk patients in 21 of the 23 hospitals were located on the same side of their 95% confidence intervals compared to that for all patients. High-risk patients and all patients differed at only one hospital. In conclusion, the impact of risk selection by hospital on the assessment results was the smallest when comparing the crude inpatient mortality rates of CABG patients with the 95% confidence intervals of predicted mortality rates. Given the increasing importance of quality improvements in Korean health policy, it will be necessary to use the appropriate method of releasing the hospital performance data to the public to minimize any unwanted impact such as risk-based hospital selection.