• 대한지리학회지
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• 제49권5호
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• pp.675-689
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• 2014

본 연구에서는 앙상블 경험적 모드 분해법을 우리나라에 적용하여 봄 시작일을 정의하고, 이에 대한 시 공간적인 변화를 분석하였으며, 봄 시작일의 변동성을 분석하여, 봄 시작일에 영향을 미치는 요인을 파악하였다. 우리나라 평균 봄 시작일은 3월 11일로 나타났고, 연구기간 동안 2.6일/10년으로 빨라졌다. 봄 시작일은 일반적으로 위도와 고도가 높아짐에 따라, 그리고 해안에서 내륙으로 갈수록 늦게 나타났다. 우리나라 봄 시작일에 영향을 미치는 요인을 파악하기 위해 상관분석을 수행하였고, 전구평균기온, 북극진동(Arctic Oscillation, AO), 시베리아 고기압이 우리나라 봄 시작일과 유의한 상관관계를 나타냈다. 봄 시작일에 영향을 미치는 지수들을 대상으로 다중회귀분석을 수행하였고, 세 가지 변수가 모두 입력된 모형은 64.7%의 설명력을 나타냈다. 다중회귀분석의 결과 봄 시작일에 미치는 영향은 전구평균기온이 가장 크고, AO가 그 다음으로 나타났다. 우리나라 봄 시작일에 영향을 미치는 종관적인 요인을 파악하기 위해 기압장 및 바람장을 분석한 결과, 시베리아 고기압, 알류샨 저기압, 상층 기압골의 강도 및 위치에 따른 북풍계열 바람의 강도가 봄 시작일을 결정하는 주요 원인인 것으로 나타났다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제31회 춘계학술대회
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• pp.153-158
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• 2000

The purpose of present paper is to prove an improvement on stability of plane Journal bearing due to the leaf spring damper(LSD) experimentally A flexible rotor system is designed and manufackuea in order to generate oil whip instability of journal bearing at relative lower rotating speed. Vibration amplitude and instability onset speeds are investigated for a conventional plane journal bearing and plane journal bearing with LSD. To investigate the damping effects of LSD on stability of bearing, experiments are also conducted on the leaf spring dampers with and without working oil. It is found that the leaf spring damper can considerably increase the instability onset speed of a plane journal bearing.

• Tribology and Lubricants
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• 제17권3호
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• pp.185-190
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• 2001

The purpose of present paper is to prove an improvement on stability of plane journal bearing due to the leaf spring damper (LSD) experimentally. A flexible rotor system is designed and manufactured, in order to generate oil whip instability of journal bearing at relative lower rotating speed. Vibration amplitude and instability onset speeds are investigated for a conventional plane journal bearing and plane journal bearing with LSD. To investigate the damping effects of LSD on stability of bearing, experiments are also conducted on the leaf spring dampers with and without working oil. It is found that the leaf spring damper can considerably increase the instability onset speed of a plane Journal bearing.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.294-298
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• 2008

Snow cover is a potential water resource for later spring and summer seasons as well as a thermal mirror with high reflectivity causing decreases of surface air temperature during cold winter seasons. In this study, current and future changes in Northern Hemisphere snow extent and their potential linkages with atmospheric circulation are examined. The NOAA AVHRR visible snow extent (1967-2006) data as well as observational (NCEP-DOE 1979-2006) and modeled (GFDL 2.1 2081-2100) pressure and surface air temperature data are used. Analyses of observational data demonstrate that the snow extent in meteorological spring (March to April) and summer (June to August) has significantly decreased since the late 1980s. The offset of snow seasons (the timing of snow melt in spring) have also significantly advanced particularly in Europe, East Asia, and northwestern North America. Analyses of pressure fields reveal that the spatial patterns of the earlier snow melt are associated with changes in atmospheric circulation such as the Arctic Oscillation (AO). In the positive winter AO years, multiple positive pressure departure cores in the upper troposphere (200hPa) are observed over the mid-latitude regions from March to mid-April, while a negative pressure departure core (70hPa) prevails over the Arctic Ocean. The reversed anomaly patterns related to later snow melt occur in negative winter AO years. The comparison between current and future thermal spring onsets suggest that snow melt patterns will intensify with larger greenhouse gas emissions, indicating earlier hydrological spring onset.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제17권1호
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• pp.47-51
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• 2014

Purpose: Neonatal late-onset hypocalcemia is defined as hypocalcemia developed after postnatal 3 days and associated with hypoparathyroidism, high phosphate diets and vitamin D deficiency. We experienced the increment of neonatal late onset hypocalcemia over 1 year. We tried to evaluate the relationship between late onset hypocalcemia and maternal hypovitaminosis D. Methods: The medical records in the neonates with late-onset hypocalcemia during January 2007 to July 2008 were retrospectively reviewed. Among those patients, 17 paired sera of mothers and neonates had collected. The levels of 25-OH vitamin D (25OHD) and intact parathyroid hormone (iPTH) were measured and were compared with neonate and the mother. Results: The mean gestational age was $38^{+1}$ weeks, and the mean body weight was 2,980 g. The onset time of hypocalcemia was 5.9 days of age. Most of them (88.2%) were feeding with formula and no one was only breast milk feeding. Of the 17 patients, 13 were born in spring or in winter. The median levels of calcium, phosphorus, alkaline phosphatase, iPTH and 25OHD were 7.0 mg/dL, 8.6 mg/dL, 191.0 U/L, 57.2 pg/mL and 24.0 ng/mL in neonates. The levels of 25OHD of 6 neonates were <20 ng/mL. A total of 16 mothers were considered vitamin D-deficient (<20 ng/mL), and vitamin D insufficient (20<25OHD<30 ng/mL). Conclusion: Neonatal late-onset hypocalcemia in our study seems to be influenced by maternal vitamin D deficiency and insufficiency. Sun tanning and vitamin D supplements from winter to spring would be helpful to prevent maternal vitamin D deficiency, one of the causes of neonatal late-onset hypocalcemia.

• 대한지리학회지
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• 제43권1호
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• pp.36-51
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• 2008

지구 온난화는 농업, 수산업, 임업, 보건 등 사회 여러 분야에 걸쳐 인간에게 영향을 미치고 있으므로 기후변화에 따른 영향을 평가하고 적응 방안을 모색하는 일은 우리에게 당면한 과제이다. 이를 해결하기 위해서는 현재 기후를 정확히 분석하는 것뿐만 아니라 미래 기후를 전망하는 것이 필요하다. 본 연구에서는 30년간$(1971\sim2000)$의 관측 자료와 IPCC SRES A1B 시나리오에 근거한 2090 년대$(2091\sim2100)$ 전망 자료에 로패스 필터링 기법을 적용하여 계절 시작일 및 계절 지속기간의 공간 분포 변화를 분석하였다. 계절 시작일의 공간 분포를 보면, 봄과 겨울 시작일은 위도, 지형 및 해양의 영향을 많이 받으나, 여름과 가을 시작일은 위도에 의한 영향은 거의 없고, 해양과 지형에 의해서만 일부 영향을 받는다. 2090년대의 계절 시작일을 보면, 남해안과 동해안 및 남부 내륙 지역에서는 현재보다 봄은 40일 정도, 여름은 $25\sim30$일 정도 빨리 시작되며, 가을은 20일 정도, 겨울은 50일 정도 늦게 시작될 것으로 전망되었다. 또한 계절 지속기간을 보면, 2090년대에는 남해안과 동해안 및 남부 지방에서 겨울철은 더 짧아지고 여름철은 더 길어질 것으로 전망되었다.

• 한방안이비인후피부과학회지
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• 제23권3호
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• pp.202-215
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• 2010

Objective : This study was performed to investigate the prevalence of otolaryngology and respiratory diseases and characteristics of the outpatients who had visited Chuncheon oriental medical hospital which located in Gangwon province with the diseases. Methods : We analyzed data from 627 patients, who had visited to the Department of ophthalmology & otolaryngology & dermatology of Chuncheon oriental medical hospital from November 1st, 2007 to May 31th, 2010. The data were analyzed and demonstrated by age, gender, season, period between the onset of disease and the first examination, times of treatment, and treatment methods. Results : The results of this study are summarized as follows. 1. Among the 627 outpatients, male patients outnumbered female patients, and the most frequent age group was 0-10 year-old group(24.9%) and it is followed by 31-40 and 41-50 year-old groups. The majority of outpatients, 79.7% of them were from Chuncheon, and Hongcheon and Gapyeong residents were respectively 4.7% and 3.8% of the patients. 2. The shares of outpatients by department were 47.4% in Rhinology disease, 29.8% in respiratory disease, 14.5% in Otology disease, and 8.3% in Laryngology disease. The seasons with the most frequent prevalence by department were spring and winter for otology group, autumn and spring for rhinology group, summer and spring for laryngology group, and winter and spring for respiratory disease group. Overall, most outpatients had visited the hospital for 1-5 times or 6-10 times. Acupuncture and herbal medicine were the most frequent treatment methods that these patients received. 3. The most prevalent diseases were rhinitis, common cold, tinnitus, and sinusitis. The most frequently visited age groups for tinnitus and hearing loss were 41-50 and 51-60 year-old groups, and for rhinitis and sinusitis 0-10 and 11-20 year-old groups. Irritation in larynx was almost evenly prevalent among 31-40, 41-50 and 51-60 age groups. Regarding the period between the onset of disease and the first medical examination, outpatients with tinnitus, rhinitis, sinusitis, and irritation in larynx came to the hospital after one year since the onset and outpatients with common cold first visited the hospital within one week since the onset of disease. Conclusions : This study shows that the most frequent diseases were rhinitis, common cold, sinusitis, tinnitus, and cough. In order to do better treatment for these diseases in the future, there is a need to investigate long-term, multifaceted studies, connected studies with other hospital in Gangwon province.

• 대한지리학회지
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• 제41권4호
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• pp.435-456
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• 2006

본 연구에서는 일기온 자료를 바탕으로 사계절을 정의하여 지난 32년(1973-2004)동안 우리나라 장기간 평균적인 사계절의 개시일과 지속기간의 공간적 분포패턴 및 최근의 그 변화추세를 분석하였다. 공간적으로, 장기간 평균적인 봄철과 겨울철 개시일은 위도 및 해발고도의 영향을 받아 남-북(성산포-대관령)으로 각각 최고 44일과 63일의 차이를 보인다. 반면, 여름철 개시일은 위도보다는 해양과 해발고도의 영향을 받아 한반도 내륙지역에서 여름철이 제주도보다 일찍 시작된다. 사계절 지속기간에 따라 긴 계절부터 짧은 계절 순으로의 조합의 공간적 패턴을 살펴보면, 우리나라에는 특징적으로 5개의 계절주기 기후유형이 군집되어 나타난다. 한편, 최근 한반도에 나타난 기후변화가 계절주기에도 반영되어, 1980년대 후반 이후에 우리나라의 전체적으로 겨울철 개시일은 4일 늦어지고, 봄철 개시일은 6일 빨라져서 겨울철 길이가 10일 정도 짧아졌다. 이러한 겨울철 축소현상은 1980년 중반이후 남부지방에서 시작되어 1990년 접어들면서 북쪽으로 확대되어 한반도 전역에 걸쳐 나타났다. 인위적으로 콘크리트화가 진행된 우리나라 대도시 지역에서는 이러한 겨울철 축소현상이 더 뚜렷하게 나타났고, 심지어 여름철 지속기간도 국지적으로 증가하는 특징을 보였다. 이러한 한반도의 겨울철 축소현상은 추운계절 동반구 극지방($0-90^{\circ}E$, $65-85^{\circ}N$)의 지오포텐셜 고도장(925hPa) 변화와 원격상관이 있는 것으로 나타났다. 본 연구에서 밝혀진 우리나라 겨울철 지속기간의 감소현상은 최근 전 세계적인 기후변화의 시그널로 나타나는 겨울철 기온상승 추세와 일치하는 결과이다.

• 한국수산과학회지
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• 제36권2호
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• pp.178-186
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• 2003

Seasonal variation of phytoplankton was investigated with surface mixed layer ecosystem model in the East Sea. The model consisted of four compartments (phytoplankton, zooplankton, nutrient, detritus) forced by mixed layer depths, photosynthetically available radiation and nutrient concentrations. From model results we estimated entrainment rate $2.5-4.0\;m{\cdot}day^{-1}$ to reproduce the two annual blooms, and reproduced seasonal variation of phytoplankton at southern and northern regions by the difference of surface winter mixed layer depth (MLD) using the entrainment rate value $3.0\;m{\cdot}day^{-1}$. The spring blooms in the southern and northern regions closely related to deepening of a winter surface MLD. In the southern region where MLD was shallow and phytoplankton spring bloom occurs one month in advance to the northern region where MLD was deep. The amount of light increases within the MLD during the onset of stratification and water temperature increases faster in spring in the southern region than the northern region. Decrease of phytoplankton was mainly affected by zooplankton grazing in the southern region and by nutrient exhaustion in the northern region. The fall bloom in the two regions was caused by the nutrient availability and entrainment on the phytoplankton.

• Journal of Ginseng Research
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• 제28권4호
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• pp.165-172
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• 2004

Ginseng is traditionally cultivated worldwide in cold continental climates. It is now also being cultivated in maritime environments such as New Zealandis. This paper reports a number of growth and quality parameters for plants grown under those conditions over two growing seasons and the intervening winter dormant period. While shoot biomass peaked mid-summer, in contrast, root biomass peaked late autumn/early winter. Starch, sucrose, fructose, glucose and inositol were detected in the roots. Starch concentrations were highest in early autumn (mean 470 mg $g^{-1}$ dry weight) and lowest in mid spring (218 mg $g^{-1}$ dry weight). Sucrose concentrations were low during early summer until late autumn but increased rapidly with the onset of winter and peaked during mid spring (168 mg $g^{-1}$ dry weight). Fructose and glucose concentrations were similar and peaked in late spring (5.3 and 6.2 mg $g^{-1}$ dry weight). Inositol concentrations peaked in mid summer (1.7 mg $g^{-1}$ dry weight). Starch/sugar ratios were high during summer and autumn and low during winter and spring. Ginsenoside concentrations and profiles showed that the six major ginsenosides, Rgl, Re, Rb1, Rc, Rb2 and Rd, were present, but Rf was absent. Concentrations did not vary with sampling date. The most abundant ginsenosides were Re (15.9 to 17.5 mg $g^{-1}$ dry weight) and Rb1 (10.7 to 18.1 mg $g^{-1}$ dry weight). Combined, they accounted for < $75{\%}$ of total ginsenoside concentrations. Limited taste tests indicated that highest root quality occurred during late autumn, after the shoots had senesced. However, quality could not be related to plant chemistry.