• Title/Summary/Keyword: circulation periods

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The Intensification of Walker Circulation over the Past 15 Years from 1999 and Its Relation to TC Activity in the Western North Pacific

  • Choi, Jae-Won;Cha, Yumi;Kim, Jeoung-Yun
    • Journal of the Korean earth science society
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    • v.37 no.6
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    • pp.359-372
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    • 2016
  • The time-series of Walker circulation index (WCI) in this study shows the strengthening of the Walker circulation in recent years. To further understand the large-scale features related to the WCI strengthening, a difference between the averaged meteorological variables in two time periods 1999-2013 and 1984-1998 is analyzed. The difference in 850 hPa stream flows between the two periods shows that the anomalous easterlies (anomalous trade wind) are dominant due to the strengthening of anomalous anticyclonic circulations at the subtropical Pacific of both hemispheres. The difference between the averaged zonal atmospheric circulations over $5^oS-5^oN$ in the two periods confirms that upward flows are strengthened at the tropical western Pacific and downward flows are strengthened at the tropical central and eastern Pacific in recent years. It matches the WCI strengthening in recent years. The time-series of tropical cyclone (TC) genesis frequency from July to September shows that a mean TC genesis frequency from 1999-2013 decreases compared to that of the time period 1984-1998. The monsoon trough in the period 1984-1998 was located in the further east direction and stronger than that in the period 1999-2013. TCs in the recent period that are generated in further west than TCs in the past period moved from the west. Thus, the TC intensity along the coasts in East Asia becomes weaker in recent period. The intensification of Walker circulation in recent years is related to the weaker TC intensity in East Asia through strengthened anomalous anticyclones at the subtropical western Pacific.

Studies on the Changes of Vitamin C content in the Hot Green Pepper Fruits during the Circulation Periods (풋고추의 유통과정중 Vitamin C 함량의 변화)

  • 김상옥
    • Journal of the Korean Home Economics Association
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    • v.19 no.3
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    • pp.41-45
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    • 1981
  • This study was carried out to observe the changes of Vitamin C content and to preserve the quality for the circulation periods of hot green pepper fruits wrapped with polyethylene film under the indoor temperature, as well as to find the proper time for harvest of hot green pepper fruits as a hot taste food and vegetable. the results obstained were as follows: 1. The consignment rate of hot green pepper fruits was highest, 60.2% on the 25th day after flowering, the nest 25.4% on the 20 th day, 10.3% on the 30th day and 4.1% on the 35th day. 2. the content of Vitamin C I each pepper fruits was highest o the 30th day, considerably high on the 25th day and 20th day. 3. The total content of Vitamin C in each part of hot green pepper fruits; the content in pericarp was much higher than in placenta and seed, and that of hydro type Vitamin C was almost the same. 4. The reduction rate of vitamin C during circulation periods was highest on the 3rd day; 42% in pericarp, 50% in placenta, 65% in seed. But in the package wrapped up with polyethylene film, the reduction rate in the same period was 5% in pericarp, which was very low in reduction, and those in placenta and seed were almost the same as in the unwrapped state.

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A Study on Efficient Administration of Library Collections with Emphasis on Establishment of Weeding Criteria (도서관 장서의 효율적인 운영방안에 관한 연구 -장서의 폐기기준 설정을 중심으로-)

  • Lee, Un-Chul
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.4 no.1
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    • pp.103-127
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    • 1980
  • Due to the rapid growth of publications, librarians have been facing the problems caused by the shortage of stack as well as the quality deterioration of library collections. This naturally disappointed the user communities and the present library activities are weak and inadequate. It seems to the author that one of the desirable actions in remedying this problems is to weed library collections properly and regulraly. The purpose of this study is to establish weeding criteria in library collections, particulary in the fields of polictical science, economics and law In order to establish weeding criteria, shelf-time period which is the length of time that a book remains on the shelf between the last two users of a volume, was measured by examining the book cards or date-due slips of circulating books and collections which remained in the stack. The results of this study are as follows: (1) In the fields of political science economics and law, the shelf-time periods of general materials in Korean for circulation was measured. (2) This study shows shelf-time periods that vary in different subject fields. (3) Combining the shelf-time periods of books in active circulation and the total collection including books which have never been circulated, the size of library holdings which may satisfy a certain percentage of the current circulation can be estimated.

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A Clinical Study on Change of Platelet Count Associated with Extracorporeal Circulation (체외 순환에 따른 혈소판수의 변화에 관한 임상적 연구)

  • 김영진
    • Journal of Chest Surgery
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    • v.25 no.3
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    • pp.240-246
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    • 1992
  • The effects of extracorporeal circulation on plateler count were studied in 120 patients. We measured platelet count before, during, after extracorporeal circulation, and postoperative 0, 1, 3, 5, 7, 9, 11th days to evaluate the effects of total extracorporeal circulation time and types of oxygenator on changes of platelet count The patients were classified into group I [extracorporeal circulation time < 100 minutes, 45 patients], II [100 < extracorporeal circulation time < 200 minutes, 48 patients], III [extracorporeal circulation time >200 minutes, 27 patients], and also all patients were classified into group B [bubble oxygenator, 84 patients] and group M [membrane oxygenator, 36 patients]. The group I, II, III were subclassified into IB, IM, IIB, IIM, IIIB and IIIM according to the types of oxygenator. The results were as follows: 1. The platelet counts were reduced throughout extracorporeal circulation and in the early postoperative periods upto postoperative third day. 2. The platelet counts after postoperative 9th to 11th day increased significantly compared with those of preoperative levels. 3. After extracorporeal circulation, the platelet recovered gradually in all groups, especially faster in group I compared with those of group II and III. 4. The effect of the type of oxygenator on the recovery of platelet count was not significant. In conclusion, extracorporeal circulation time influenced the change of platelet count. Therefore, in order to prevent of decrease of platelet count associated with extracorporeal circulation time, the extracorporeal circulation time should be shortened.

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Authigenic Neodymium Isotope Record of Past Ocean Circulation (과거 해수 순환을 지시하는 해수기원 네오디뮴 동위원소 비 기록)

  • Huh, Youngsook;Jang, Kwangchul
    • The Journal of the Petrological Society of Korea
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    • v.23 no.3
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    • pp.249-259
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    • 2014
  • Proxies for paleo-circulation are drawing much interest with the recognition that ocean circulation plays an important part in the redistribution of heat and climate change on orbital and millennial timescales. In this review, we will introduce how neodymium isotope ratios of the authigenic fraction of marine sediments can be used as a proxy for ocean circulation along with analytical methods and two case studies. The first case study shows how the North Atlantic Deep Water (NADW) has varied over the glacial-interglacial and stadial-interstadial periods. The second case study shows how the freshwater budget and water circulation within the Arctic Ocean can be reconstructed for the last glacial period.

Circulation Trends of a Public Library during the Covid-19 Era: An Analysis of Circulation Statistics of A Public Library from 2019 to 2021 (코로나 시대의 공공도서관 대출 추이에 관한 연구 - A 공공도서관의 2019~2021 대출 통계 분석을 중심으로 -)

  • Soyeon, Park
    • Journal of the Korean Society for Library and Information Science
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    • v.56 no.4
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    • pp.357-376
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    • 2022
  • This study examines circulation status and trends of a public library during three year periods from January 2019 to December 2021. There was a statistically significant difference in the mean number of circulation between the pre-Covid-19 period and the Covid-19 period, and the Covid-19 period and the Covid-19 recovery period. However, no significant difference was found between the pre-Covid-19 period and the Covid-19 recovery period. Across three years, there was a significant difference in the distribution of circulation per month. Circulation distribution was also significantly different among different days of the week and different hours of the day. Monthly circulation distribution and hourly circulation distribution during the pre-Covid-19 period was similar to those of the Covid-19 recovery period, whereas those of the Covid-19 period differed from the pre-Covid-19 period and the Covid-19 recovery period. It is expected that the results of this study could contribute to the collection development, and the management and improvement of services of public libraries. It is also expected that the results of this study could contribute to the prediction of circulation patterns and information needs of public library users.

Circulation State of Strawberry and Quality Changes during Ripening (딸기의 유통실태와 성숙중의 품질변화)

  • 박인경;장경숙
    • Food Science and Preservation
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    • v.1 no.1
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    • pp.45-53
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    • 1994
  • Circulation state and changes in quality during ripening of strawberry were investigated. Tissue damage of the fruit happened when it was harvested and selected. Strawberry has been harvested without considering of fruit temperature in the farm. It takes 25 hours from Goreung which is main production area of strawberry to retailer, and seasonal variation in the price was severe. Shelf-life of strawberry from Feb to Mar was 5-6 days, and was 24-30 hours from May to June. Desirable ripening stage was 28-30th day after blooming and 40th day and after this was over ripening stage when the degree of ripening estimated by color "a" value and color saturation. Overall eating quality and vitamin C contents and sugar content were more higher in the fruit of the desirable ripening stage than that of unripening and over ripening stage. The dark redness degree was high in the over ripening stage.

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Development and Assessment of LSTM Model for Correcting Underestimation of Water Temperature in Korean Marine Heatwave Prediction System (한반도 고수온 예측 시스템의 수온 과소모의 보정을 위한 LSTM 모델 구축 및 예측성 평가)

  • NA KYOUNG IM;HYUNKEUN JIN;GYUNDO PAK;YOUNG-GYU PARK;KYEONG OK KIM;YONGHAN CHOI;YOUNG HO KIM
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.29 no.2
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    • pp.101-115
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    • 2024
  • The ocean heatwave is emerging as a major issue due to global warming, posing a direct threat to marine ecosystems and humanity through decreased food resources and reduced carbon absorption capacity of the oceans. Consequently, the prediction of ocean heatwaves in the vicinity of the Korean Peninsula is becoming increasingly important for marine environmental monitoring and management. In this study, an LSTM model was developed to improve the underestimated prediction of ocean heatwaves caused by the coarse vertical grid system of the Korean Peninsula Ocean Prediction System. Based on the results of ocean heatwave predictions for the Korean Peninsula conducted in 2023, as well as those generated by the LSTM model, the performance of heatwave predictions in the East Sea, Yellow Sea, and South Sea areas surrounding the Korean Peninsula was evaluated. The LSTM model developed in this study significantly improved the prediction performance of sea surface temperatures during periods of temperature increase in all three regions. However, its effectiveness in improving prediction performance during periods of temperature decrease or before temperature rise initiation was limited. This demonstrates the potential of the LSTM model to address the underestimated prediction of ocean heatwaves caused by the coarse vertical grid system during periods of enhanced stratification. It is anticipated that the utility of data-driven artificial intelligence models will expand in the future to improve the prediction performance of dynamical models or even replace them.

Changes in the Low Latitude Atmospheric Circulation at the End of the 21st Century Simulated by CMIP5 Models under Global Warming (CMIP5 모델에서 모의되는 지구온난화에 따른 21세기 말 저위도 대기 순환의 변화)

  • Jung, Yoo-Rim;Choi, Da-Hee;Baek, Hee-Jeong;Cho, Chunho
    • Atmosphere
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    • v.23 no.4
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    • pp.377-387
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    • 2013
  • Projections of changes in the low latitude atmospheric circulation under global warming are investigated using the results of the CMIP5 ensemble mean. For this purpose, 30-yr periods for the present day (1971~2000) and the end of the $21^{st}$ century (2071~2100) according to the RCP emission scenarios are compared. The wintertime subtropical jet is projected to strengthen on the upper side of the jet due to increase in meridional temperature gradient induced by warming in the tropical upper-troposphere and cooling in the stratosphere except for the RCP2.6. It is also found that a strengthening of the upper side of the wintertime subtropical jet in the RCP2.6 due to tropical upper-tropospheric warmings. Model-based projection shows a weakening of the mean intensity of the Hadley cell, an upward shift of cell, and poleward shift of the Hadley circulation for the winter cell in both hemispheres. A weakening of the Walker circulation, which is one of the most robust atmospheric responses to global warming, is also projected. These results are consistent with findings in the previous studies based on CMIP3 data sets. A weakening of the Walker circulation is accompanied with decrease (increase) in precipitation over the Indo-Pacific warm pool region (the equatorial central and east Pacific). In addition, model simulation shows a decrease in precipitation over subtropical regions where the descending branch of the winter Hadley cell in both hemispheres is strengthened.

Study on the effect of refrigeration storage periods on the quality of frozen croissant dough (크라상생지의 냉동보존기간이 품질에 미치는 영향에 관한 연구)

  • Kim, Jong-Uk
    • Journal of Applied Tourism Food and Beverage Management and Research
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    • v.15 no.2
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    • pp.57-72
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    • 2004
  • This study is carried out to investigate the effect of any periods in the freezer and the product of value, moisture content, baking loss, specific volume loaf in manufncturing process thereof. The moisture content of the croissant slightly decreased as the periods passed in the freezer. And as passed periods frozen croissant dough dried naturally by the freezer fan. 1. As frozen periods passed croissant dough decreased moisture content and loaf volume. The volume is relation to the molsture content and croissant dough' gluten. Yeast is active but croissant dough is dried so pastry margarine's moisture vaporized little by little. 2. 1 day frozen bench time provided maximum specific loaf volume while croissant shape was unsettled, moisture content was highest. At the same dough croissant hardness had very sofi crust. 3. 1week and 2weets frozen dough had specific loaf volume and hardness with proper crust color. As the proper bench time provided best shape of croissant, color. 4. 4weeks and 8weeks frozen dough had over-al] value of croissant accelerating older product. As the same result, over Sweets frozen periods product were not available for sale and serving to customers. 5. By the sensory evaluation tests, over-all croissant as 1 week, 2weeks were significantly higher quality those than 6. 1day, 4weeks and 8weeks. Textural properties of croissant over 4weeks frozen periods so hard for every panel. According to the study, not croissant dough but also any other frozen dough(ex.Danish, brioche etc.)have to need proper bench time and 1week or 2weeks circulation making method have to given encouragement to practical pastry industry. Add to this study using only for frozen dough yeast instead of using fresh and instant

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