• 한국작물학회지
• /
• 제12권
• /
• pp.43-48
• /
• 1972

CEPA를 답전작 및 우기전에 수확이 가장 빨리 촉진되면 또 니코친 함량이 저감되는지를 알고저 Yellow Special A 품종을 공시하여 적심 직후해당 농도의 CEPA 수용액을 살포한 후 일정기간을 두고 수확하여 처리수준별 성숙도 및 전 alkaloid함량을 조사하였던 바 그 결과는 다음과 같았다. 1) 처리농도가 높을수록 잎담배 성숙에 미치는 효과가 컸으며 그 효과는 처리 후 6-11일간에 있어서 현저하였다. 2) CEPA는 엽표면에만 처리해도 효과가 있으며 성숙촉진효과는 처리부분에 있어서 더욱 뚜렷하였다. 3) 처리농도가 높을수록 잎담배의 전 alkaloid 함량이 감소되는 경향이 있으며 그 효과는 성숙촉진작용후에 더 크게 나타났다. 4) CEPA의 성숙촉진작용은 성수기에 가까운 하부엽에서 컸고 alkaloid 축적억제작용은 반대로 숙기에 도달하지 않은 상부엽에서 컸다. 그러나 적기수확엽에 있어서는 축적억제효과가 부위에 관계없이 같았다. 5) CEPA 처리는 수량에 변화를 주지 않았으며 시용 적정농도는 500-2,000ppm 사이라고 느껴졌다. 6) CEPA의 성숙촉진 및 alkaloid 합성억제작용의 기구에 관하여는 금후 더욱 연구할 필요가 있다고 보았다.

• 한국도로학회논문집
• /
• 제18권1호
• /
• pp.13-21
• /
• 2016

PURPOSES : In this study, we analyzed the compressive strength characteristics of lean base concrete in relation to changes in the outdoor temperature after analyzing the cold and hot weather temperature standards and calculated the minimum and maximum temperatures when pouring concrete. We examined the rate of strength development of lean base concrete in relation to the temperature change and derived an appropriate analysis formula for FRC base structures by assigning the accumulated strength data and existing maturity formula. METHODS : We measured the strength changes at three curing temperatures (5, 20, and $35^{\circ}C$) by curing the concrete in a temperature range that covered the lowest temperature of the cold period, $5^{\circ}C$, to the highest temperature of the hot period, $35^{\circ}C$. We assigned the general lean concrete and FRC as test variables. A strength test was planned to measure the strength after 3, 5, 7, 14, and 28 days. RESULTS : According to the results of compressive strength tests of plain concrete and FRC in relation to curing temperature, the plain concrete had a compressive strength greater than 5 MPa at all curing temperatures on day 5 and satisfied the lean concrete standard. In the case of FRC, because the initial strength was substantially reduced as a result of a 30% substitution of fly ash, it did not satisfy the strength standard of 5 MPa when it was cured at $5^{\circ}C$ on day 7. In addition, because the fly ash in the FRC caused a Pozzolanic reaction with the progress into late age, the amount of strength development increased. In the case of a curing temperature of $20^{\circ}C$, the FRC strength was about 66% on day 3 compared with the plain concrete, but it is increased to about 77% on day 28. In the case of a curing temperature of $35^{\circ}C$, the FRC strength development rate was about 63% on day 3 compared with the plain concrete, but it increased to about 88% on day 28. CONCLUSIONS : We derived a strength analysis formula using the maturity temperatures with all the strength data and presented the point in time when it reached the base concrete standard, which was 5 MPa for each air temperature. We believe that our findings could be utilized as a reference in the construction of base concrete for a site during a cold or hot weather period.

• 동굴
• /
• 제24권25호
• /
• pp.1-14
• /
• 1991

Jeongsun limestone formations with good geochemical solution of limestone and physical environments have been developing many Karst landforms. Especially, there are many dolines and most of them elliptical shapes of planes. At present, they have been transformed into uvala toward their long diameter directions. The period of landscape processing is a Quaternary Epoch and Karst cycle corresponds to a stage from late maturity to old stage.

• 재무관리연구
• /
• 제23권2호
• /
• pp.85-107
• /
• 2006

이 논문에서는 새로운 뉴스에 대해 선물시장이 현물시장보다 더 민감하게 반응하는지와 더 큰 가격변동폭을 보이는지를 검증한다. 뉴스에 대한 민감도는, 선물가격의 일간변동을 이론가격 변동에 관해 회귀시킨 식의 회귀계수에 의해 측정한다. 그리고 가격변동폭은 선물가격과 이론가격의 평균범위차이($\overline{RD}$), 평균고가차이($\overline{HD}$) 및 평균저가차이($\overline{LD}$)라는 세 가지 척도를 사용하여 측정한다. 이 논문에서 사용한 자료는 코스피200 지수선물시장의 개설 초기인 1996년 7월부터 최근의 2005년 12월말까지 최근월물과 차근원물의 선물가격과 이론가격이다. 민감도의 차이를 나타내는 $\hat{\beta}$는 1과 크게 유의한 차이를 보이지 않으므로 뉴스에 대한 두 시장의 민감도는 대체로 큰 차이가 있는 것으로 보이지 않는다. 그러나 최근기간(2002년 11월${\sim}$2005년 12월)에는 최근월물 및 차근월물 모두 1보다 큰 값을 보이고 있어 선물시장이 더 민감하게 반응하고 있다. 또 최근기간에 최근월물의 가격이 좋은 뉴스에 대해 현물시장보다 더 민감하게 반응하였다. 전체기간 및 하위기간의 ($\overline{RD}$)는 대체로 0과 유의한 차이를 갖지 않는다. 그러나 최근월물의 평균고가차이($\overline{HD}$)는 전체기간과 하위기간 모두에서 뚜렷하게 유의한 양의 값을 보이고 있다. 이것은 최근월물 선물가격의 좋은 뉴스에 대한 가격변동폭이 현물가격보다 더 크다는 것을 의미한다.

• 한국해양학회지
• /
• 제18권2호
• /
• pp.161-168
• /
• 1983

淺水灣에 書式하는 전어의 體長, 年齡 및 成熟度를 分析하여 年齡造成과 繁殖期에 대하여 考察하였다. 資料는 1981年 5月부터 1982年 12月 사이 灣入口에서 小型定置網으로 收集하였다. 전어는 봄에 水溫이 8$^{\circ}C$ 程度로 上昇하였을 때 灣으로 들어 온다. 여름 동안 이곳에서 자란 후, 가을에 水溫이 8$^{\circ}C$ 以下가 되기 전에 灣을 빠져 나간다. 전어는 태어난 첫해에 가장 빨리 자라며, 1-4歲群의 平均體長은 각각 12.2, 15.8, 17.6 및 20.9cm 이었다. 觀察된 가장 큰 個體는 22.0cm었고 나이는 4歲 이었다. 淺水灣 전어는 태어난지 2年이 지나면 夙成되며, 이때 體長은 14cm에 이른다. 成熟年齡과 體長을 分析한 缺課 전어의 成熟은 年齡에 의하여 決定되지 않고 體長에 左右됨이 밝혀 졌다. 전어는 水溫이 8-15$^{\circ}C$인 4月末에서 5月末 사이 産卵한다.

• 대한수의학회지
• /
• 제33권2호
• /
• pp.277-283
• /
• 1993

In the present study, observations were made on the life-history of Lymnaea viridis under laboratory conditions, involving incubation period of the eggs and their hatching rate, shell length of the newly hatched snails, sexual maturity, size of the snails when the snail produced the first egg-mass, the number of eggs in each egg-mass, egg-laying, ovipostion, growth rate of the snails, and longevity of the snail. At temperatures between $19.8^{\circ}C$ to $22.5^{\circ}C$, incubation period of the eggs occupied 10~12 days, and after beginning of hatching, all young snails emerged completely from the egg-mass within 5 days. The hatching rate was 88%. The average shell length of the newly hatched snails was about 0.064cm. The rate of growth was extraordinarily rapid under good laboratory conditions. When two snails were reared in one culture vessel($20{\times}15{\times}5cm$) with blue-green algae at about $22^{\circ}C$, snail growth was optimal, taking 37 days to reach 1.2cm in shell length. Sexual maturity reached in about 19 days. The size of the snails at sexual maturity was $0.78{\pm}0.05cm$ in length and $0.47{\pm}0.04cm$ in width. The first egg-masses produced were $0.59{\pm}0.22cm$ in length and $0.34{\pm}0.08cm$ in width, and contained 7~38 eggs. The eggs are usually laid in water. The egg-laying was affected by food and temperature. Snails fed with blue-green algae at about $22^{\circ}C$ produced larger egg-masses than the snails fed with fish food at about $26^{\circ}C$. Under conditions of continuous activity and growth, the maximum expectation of life appears to be 109~350(mean 230) days. And the shell length of snails at death were 1.39~1.64cm.

• Animal cells and systems
• /
• 제5권1호
• /
• pp.37-44
• /
• 2001

Gonadal development, reproductive cycle, gonad index, meat weight rate, and first sexual maturity of the top shell, Omphalius rusticus were Investigated monthly by histological observations. Specimens were collected from the west coast of Korea during the period from January to December in 1999. O. rusticus is dioecious and oviparous. The gonad is widely situated on the surface of the digestive g1and located in the posterior spiral meat part in the shell. The ovary and the testis were composed of a number of oogenic follicles and several spermatogenic follicles, respectively. Ripe oocytes were approximately 120-130 $\mu$m in diameter. The meat weight rate peaked in June (27.7%), and then rapidly decreased in September (19.5%). Monthly changes in the gonad index in both sexes reached the maximum in June, and then sharply decreased in September. Percentages of first sexual maturity of female and male snails ranging from 9.0 to 9.9 mm in shell heights were 58.3% and 54.5%, respectively, and 100% in those over 11.0 mm in both sexes participated in reproduction. Reproductive cycle of this species can be categorized into five successive stages: in females, early active (October to April), late active (December to June), ripe (April to September), spawning (July to September) and recovery (September to January): in males, early active (November to March), late active (December to June), ripe (April to September), spawning (July to September) and recovery (September to December). Gonadal development, gametogenesis, reproductive cycle, and spawning were closely related to the seawater temperature.

• 수산경영론집
• /
• 제44권2호
• /
• pp.1-17
• /
• 2013

We investigate the appropriateness of the fixed 12% discount rate to be used in estimating the amount of compensation for revoking a license for fishery business by the Enforcement Decree of Fisheries Act in Korea. We also suggest the appropriate discount rate fully reflecting the change of market interest rate in the Korean financial market. The capital asset pricing model, or, CAPM is the best known model of risk and return, and is widely used to estimate the expected rate of return for the risky projects. Even though the CAPM implies that the discount rate or the expected rate of return should change as the related market factors do, the discount rate used to estimate compensation for revoking a license for fishery business remains to be the same 12% rate for the last 15 years by law. During this period, however, the yield to maturity for the 5-year government bonds in Korea has dramatically changed from about 12% to less than 3%. In order to provide the fair compensation for the damages against the coastal fisheries and evaluate the intrinsic value of fishery resources in the coastal areas, we suggest that the appropriate discount rate should be determined by the yield to maturity of the government bonds with 5-year maturity, instead of the current fixed 12% interest rate.

• 한국수산과학회지
• /
• 제57권4호
• /
• pp.380-388
• /
• 2024

This study investigated the sexual maturation of the marbled flounder Pseudopleuronectes yokohamae, a commercially important flatfish species, through monthly sampling from the coastal waters of Pohang in the East Sea of Korea in 2022. We analyzed monthly changes in total length (TL), gonadosomatic index, maturity stage, and 50%, 75%, and 97.5% group maturity based on visual assessments and histological analysis of the gonads. The spawning period was determined to be from December to May. The TL at 50% maturity was 26.4 cm for females and 24.8 cm for males. These findings provide a basis for developing resource management strategies for Pleuronectidae.

• 한국환경농학회지
• /
• 제27권4호
• /
• pp.460-463
• /
• 2008

The change of glutelin contents in rice grain during the maturity period was investigated to determine optimum rice harvesting time. The glutelin content was increased with increasing time after heading. In this study, eight of glutelin subunits were found. Among the glutelin subunits, 7208-subunit (MW, 35 kD) contents was significantly increased at 65 days after heading compared with 55 and 60 days after heading. 7405-subunit (MW, 50 kD) contents was steadily increased with time after heading. The results showed that at 55th day after heading would be optimum time for harvest to get the low glutelin content of rice grain.