• 한국산업융합학회 논문집
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• 제11권4호
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• pp.157-163
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• 2008

The present study investigated the pressure drop and the total frost mass of the louvered fin type heat exchanger, which is widely used at the air-conditioning system. The pressure drop due to the frosting phenomenon and the total frost mass were investigated by changing the wet bulb temperature condition of the inlet air. Hence the brain of 55wt% was used as a cooling solution instead of a common refrigerant. The temperature difference between the brine and the tube outside wall at the outlet of heat exchanger was $10^{\circ}C$, at maximum, higher than that at the inlet of heat exchanger. As the wet bulb temperatures were increased, the pressure drop was linearly increased due to the increment of frost mass. And the increment of heat exchange rate was smaller than that of inlet air enthalpy due to the increment of frost mass. The pressure drop of air side was rapidly increased due to the progress of frosting phenomena. The run time that the pressure drop occurred rapidly was decreased by the growth of frost.

• Journal of Forest and Environmental Science
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• 제36권1호
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• pp.17-24
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• 2020

This study aimed to figure out and compare the increment of biomass by thinning intensity focused on the plantation of the two major coniferous species (Larix kaempferi and Pinus koraiensis) of South Korea. The inventory interval was three years under the effects of three types of thinning treatments; control (no thinning), light (20% thinning) and heavy (40% thinning). The results showed standing biomass increment of both species decreased as thinning intensity increased (heavylight>control). Meanwhile, the lowest of on-site biomass changes occurred in the control plot, and the greatest was in the heavy thinning plot because thinning was involved with leaving the felling residual biomass (leaves, branches and roots) on the site. According to the results from this short-term study, unthinned stands is preferable for maximizing standing biomass as well as carbon sequestration. However long-term investigation should be considered in order to see more clear results.

• 자원환경지질
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• 제12권2호
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• pp.95-104
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• 1979

The position of any point on the earth's surface can be. represented in the spherical coordinates by surface spherical harmonics. Since geomagnetic field is a function of position on the earth, it can be also expressed by spherical harmonic analysis as spherical harmonics of trigonometric series of $a_m({\theta})$ cos $m{\phi}$ and $b_m({\theta})$ sin $m{\phi}$. Coefficients of surface spherical harmonics, $a_m({\theta})$ and $b_m({\theta})$, can be drawn from the components of the geomagnetic field, declination and inclination, and vice versa. In this paper, components of geomagnetic field, declination and inclination in the Korean peninsula are obtained by spherical harmonic analysis using the Gauss coefficients calculated from the world-wide magnetic charts of 1960. These components correspond to the values of normal geomagnetic field having no disturbances of subsurface mass, structure, and so on. The vertical and total components offer the zero level for the interpretation of geomagnetic data obtained by magnetic measurement in the Korean peninsula. Using this zero level, magnetic anomaly map is obtained from the data of airborne magnetic. prospecting carried out during 1958 to 1960. The conclusions of this study are as follows; (1) The intensity of horizontal component of normal geomagnetic field in Korean peninsula ranges from $2{\times}10^4$ gammas to $2.45{\times}10^4$ gammas. It decreases about 500 with the increment of $1^{\circ}$ in latitude. Along the same. latitude, it increases 250 gammas with the increment of $1^{\circ}$ in longitude. (2) Intensity of vertical component ranges from $3.85{\times}10^4$ gammas to $5.15{\times}10^4$ gammas. It increases. about 1000 gammas with the increment of $1^{\circ}$ in latitude. Along the same latitude, it decreases. 150~240 gammas with the increment of $1^{\circ}$ in longitude. Decreasing rate is considerably larger in higher latitude than in lower latitude. (3) Total intensity ranges from $4.55{\times}10^4$ gammas to $5.15{\times}10^4$ gammas. It increases 600~700 gammas with the increament of $1^{\circ}$ in latitude. Along the same latitude, it decreases 10~90 gammas. with the increment of $1^{\circ}$ in longitude. Decreasing rate is considerably larger in higher latitude as the case of vertical component. (4) The declination ranges from $-3.8^{\circ}$ to $-11.5^{\circ}$. It increases $0.6^{\circ}$ with the increment of $1^{\circ}$ in latitude. Along the same latutude, it increases $0.6^{\circ}$ with the increment of l O in longitude. Unlike the cases of vertical and total component, the rate of change is considerably larger in lower latitude than in higher latitude. (5) The inclination ranges from $57.8^{\circ}$ to $66.8^{\circ}$. It increases about $1^{\circ}$ with 'the increment of $1^{\circ}$ in latitude Along the same latitude, it dereases $0.4^{\circ}$ with the increment of $1^{\circ}$ in longitude. (6) The Boundaries of 5 anomaly zones classified on the basis of the trend and shape of anomaly curves correspond to the geologic boundaries. (7) The trend of anomaly curves in each anomaly zone is closely related to the geologic structure developed in the corresponding zone. That is, it relates to the fault in the 3rd zone, the intrusion. of granite in the 1st and 5th zones, and mountains in the 2nd and 4th zones.

• 한국산림과학회지
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• 제89권3호
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• pp.414-421
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• 2000

본(本) 연구(硏究)는 경기도 포천군 소흘면에 소재한 23년생(年生)의 방크스소나무 인공림(人工林) 임분(林分)을 대상으로 연년(連年) 재적생장량(材積生長量)과 재적생장율(材積生長率)을 구명(究明)하고 현실(現實) 임분축적(林分蓄積)을 파악(把握)함과 동시에 연년(連年) 재적생장량(材積生長量)을 구명(究明)하므로서 년간 벌채량(伐採量)의 조절(調節)을 합리적(合理的)으로 책정할 수 있으므로 적정(適正) 임목축적(林木蓄積)의 달성(達成) 및 유지(維持)를 위한 기초자료(基礎資料)를 제시(提示)코저 하였다. 본(本) 연구(硏究)에서는 재적생장량(材積生長量)을 합리적(合理的)으로 산출(算出)하기 위하여 표준지별(標準地別)로 흉고직경(胸高直徑), 수고(樹高), 수피후(樹皮厚)와 최근(最近) 10년동안의 core의 길이를 측정하였다. 이들의 측정치(測定値)을 이용하여 직경계별(直徑階別)로 연년(連年) 직경생장량(直徑生長量) 및 95%신뢰폭(信賴幅)의 재적생장량(材積生長量)을 산출(算出)하고 아울러 수고곡선식(樹高曲線式)을 유도(誘導)한 후 본(本) 식(式)을 이용(利用)하여 수고(樹高)값을 산출(算出)하였다. 재적표(材積表)를 이용한 재적산출(材積算出)은 본(本) 수고(樹高)값을 적용(適用)하였다. 본(本) 수종(樹種)의 재적생장관계(材積生長關係)를 구명(究明)한 결과(結果) 연년(連年) 재적생장율(材積生長率)은 7.7%이고 이의 추정오차율(推定誤差率)은 6.1%이었다. 재적(材積)은 ha당 $79.58m^3$이었고 연년(連年) 재적생장량(材積生長量)은 $6.13m^3$이었으며 이를 95%의 신뢰폭(信賴幅)으로 본다면 $5.77{\sim}6.51m^3$이었다.

• 한국물환경학회지
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• 제28권6호
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• pp.859-865
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• 2012

It is necessary to evaluate performances hitherto carried out in the management of Total Maximum Daily Loads (TMDLs) and to set up direction so that this system can be improved continuously in the future. This study was investigated load allocation achievement ratio, water quality goal achievement ratio and interrelation between water quality goal and load allocation for the first period (2004~2010). Load allocation achievement and BOD water quality goal achievement ratio were 50% and 73% in Guem River Basin, respectively. The main reason for excess of load allocation and shortfall of water quality goal were unfulfilled reduction plan and pollution sources increment. Therefore, it is necessary to develop enhanced pollution sources prediction method and make a list realizable reduction plan. 63% of the unit watershed was not interrelation between water quality goal and load allocation. The reason why water quality goal and load allocation had not correlation were water quality of upper unit watershed, increment of inflow quantity, effluent water quality of wastewater treatment plant affected the unit watershed, increment of inner productivity by algae, water quality deterioration during the specific period, river management flow, etc.

• Journal of Preventive Medicine and Public Health
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• 제52권2호
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• pp.123-130
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• 2019

Objectives: The aim of this study was to evaluate the impact of shifts in maternal age and parity on the increasing trends in the low birth weight (LBW) and very low birth weight (VLBW) rates from 2005 to 2015 in South Korea. Methods: Data from 4 993 041 live births registered with Statistics Korea during the period between 2005 and 2015 were analyzed. Applying a modified standardization method, we partitioned the total increment in the LBW and VLBW rates into (1) the increase in the LBW and VLBW rates due to changes in the maternal age and parity distribution (AP-dis) and (2) the increase due to changes in the age-specific and parity-specific rates (AP-spe) of LBW and VLBW for singleton and multiple births, respectively. Results: During the study period, the total increment in the LBW and VLBW rates was 1.43%p and 0.25%p, respectively. Among singleton births, changes in the AP-dis accounted for 79% (0.34%p) and 50% (0.06%p) of the total increment in the LBW and VLBW rates, respectively. Meanwhile, among multiple births, changes in the AP-dis did not contribute to the increase in the LBW and VLBW rates, with 100% of the increase in the LBW (1.00%p) and VLBW (0.13%p) rates being attributed to changes in the AP-spe. Conclusions: This study demonstrated that shifts in maternal age and parity were prominent contributors to the increase in the LBW and VLBW rates among singleton births between 2005 and 2015 in South Korea.

• Journal of Preventive Medicine and Public Health
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• 제44권3호
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• pp.111-117
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• 2011

Objectives: This study measured the impact of shifts in maternal age and parity on the increase in the low birth weight (LBW) rate in Korea. Methods: We obtained raw data for all 6 397 945 live births registered at the Korea National Statistical Office between 1995 and 2005. We calculated the proportion of increment in the LBW rate due to changes in the distribution of maternal age and parity (AP-dis) and the proportion due to changes in the age- and parity-specific LBW rate (AP-spe). Results: The LBW rate increased from 3.02% in 1995 to 4.28% in 2005. The multiple birth rate increased from 1.32% to 2.19% during the same period. Of the 1.26% points increment in the LBW rate, 0.64% points occurred among singleton births and 0.62% points occurred among multiple births. Changes in the AP-dis accounted for 50% of the increase in the LBW rate among singleton births, but did not contribute to the increase in the LBW rate among multiple births. The remainder of the total increment in the LBW rate was explained by the increase in the AP-spe. Conclusions: This study demonstrated that shifts in maternal age and parity among singleton births and increased multiple births were important contributors to the increment in the LBW rate. This study also revealed that the increase in the AP-spe was an equally important contributor as the shifts in maternal age and parity to the increment in the LBW rate among singleton births and was a major contributor among multiple births.

• 한국작물학회지
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• 제44권4호
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• pp.368-372
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• 1999

The practicality of utilizing chitosan as a natural antimicrobial compound to reduce soybean sprout rot was tested. Domestic and imported soybean seeds were soaked for 6 hours in solutions containing different levels of chitosan and acetic acid (glacial), and cultured at $25^{\circ}C$ for 6 days. In case of domestic seeds, soaking with 1,000ppm chitosan increased germination percentage, hypocotyl thickness, total length, and fresh weight of sprouts by 4%, 5%, 2%, and 1%, respectively. The total sprout yield was increased by chitosan in a concentration-dependent manner in that 1,000ppm chitosan resulted in 8% increment of total yield (7.47kg sprouts/kg seed). Chitosan significantly reduced sprout rot percentage to 7.0% compared to control (13.8%), and consequently enhanced marketable sprout yield by 39%. Compared to domestic seeds, the imported soybean seeds exhibited very low germination percentage regardless of chitosan treatments. Chitosan, nevertheless, consistently induced yield increment and rot decrement in imported soybean sprouts. Although 100ppm acetic acid was effective in reducing sprout rot percentage down to 11.8%, its yield-increasing effects were not as prominent as chitosan. In conclusion, soaking soybean seeds with chitosan seems to be a practical method to enhance the efficiency of soybean sprout production.

• Animal cells and systems
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• 제10권4호
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• pp.191-196
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• 2006

This study was carried out to evaluate soil carbon cycling of a 36-year-old larch (Larix leptolepis) stand in Korea. The aboveground and soil organic carbon storage, litterfall, and soil respiration rates were measured over twoyear periods. The estimated aboveground biomass carbon storage and increment were 4220 gC $m^{-2}$ and 150 gC $m^{-2}\;yr^{-1}$, respectively. Mean organic carbon inputs by needle and total litterfall were 118 gC $m^{-2}\;yr^{-1}$ and 168 gC $m^{-2}\;yr^{-1}$, respectively. The aboveground carbon increment of the stand was similar to the annual input of carbon from total litterfall. The soil respiration rates correlated exponentially with the soil temperature at a depth of 20 cm ($R^2$ = 0.86). In addition, the exponential regression equation indicated a relatively strong positive relationship between the soil respiration rates and soil temperature, while there was no significant relationship between the soil respiration rates and the soil moisture content. The annual mean and total soil respiration rates were 0.40 g $CO_2\;m^{-2} h^{-1}$ and 3010 g $CO_2\;m^{-2}\;yr^{-1}$ over the two-year study period, respectively.

• 한국산림과학회지
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• 제68권1호
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• pp.52-59
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• 1985

본(本) 연구(硏究)는 우리나라 중부(中部) 내륙지방(內陸地方)에 분포(分布)하고 있는 주요(主要) 침엽수(針葉樹)인 금강소나무, 잣나무, 일본잎갈나무, 젓나무, 구상나무에 대(對)하여 직경성장량(直經成長量)을 추정비교(推定比較)하였는데 그 결과(結果)를 요약(要約)하면 다음과 같다. 1) 흉고직경급(胸高直徑級)에 따른 연년직경성장량(連年直徑成長量)은 잣나무, 일본잎갈나무, 금강소나무, 젓나무, 구상나무의 순(順)으로 나타났다. 2) 직경성장(直徑成長)은 흉고직경(胸高直徑)이 금강소나무 95cm, 잣나무 80cm, 일본잎갈나무 80cm, 젓나무 140cm, 구상나무 85cm에 도달(到達)하면 정지(停止)되는 것으로 추정(推定)되었다. 3) 수령급(樹齡級)에 따른 흉고직경(胸高直徑) 총성장량(總成長量)은 일본잎갈나무, 잣나무, 금강소나무, 젓나무, 구상나무의 순(順)으로 나타났다. 4) 직경성장(直徑成長)은 수령(樹齡)이 금강소나무 200년(年), 잣나무 120년(年), 일본잎갈나무 120년(年), 젓나무 260년(年), 구상나무 300년(年)에 도달(到達)하면 정지(停止)되는 것으로 추정(推定)되었다. 5) 구상나무는 타수종(他樹種)에 비(比)하여 직경성장(直徑成長)이 현저(顯著)히 저조(低調)하였으며 특(特)히 젓나무와 구상나무는 성장(成長)의 둔화현상(鈍化現象)이 늦게 나타남을 알 수 있었다.