• 설비공학논문집
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• 제7권2호
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• pp.310-318
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• 1995

In this study, indoor thermal parameters were measured to investigate the characteristics of thermal environments and 138 occupants were questioned to evaluate Korean thermal comfort in office building in winter. Thermal sensation was estimated by using PMV(Predicted Mean Vote) and ET*(New Effective Temperature) indices. Comparing present experimental result with international standards and that of other research, Korean thermal responses were discussed. Seasonal difference between summer and winter was also discussed. It was found that TSV(Thermal Sensation Vote) is more sensitive than PMV to the variation of temperature and that the measured percentage of dissatisfied is higher than PPD(Predicted Percentage of Dissatisfied) in real office building environments. By regression analysis, the following regression equation has been obtained; TSV=0.432ET*-8.814 and neutral temperature is $20.4^{\circ}C$ in this case. Thermal comfort range based on 80% satisfaction is also $19.4{\sim}22.4^{\circ}C$.

• 한국태양에너지학회 논문집
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• 제33권4호
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• pp.101-110
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• 2013

The propose of this study is to understand the phenomenon of radiation and comparison of analysis of two methods. One is analysis method of same-time data and the another is analysis method of rank data. We confirmed that two methods of correlation analysis had the effectiveness and suitability. The followings are main results from this study. 1) The seasonal correlation coefficient of long and short-wave radiation is higher in winter than in summer because of high humidity in the summer season can makes easily cloud in the sky locally. 2) According to analysis method, there is big difference in correlation coefficient from 0.494(Analysis method of same-time data) to 0.967(Analysis method of rank data) with short-wave radiation by the location during summer. These results have significant value in solar radiation research and analysis. It has explored a new way for solar radiation research of analysis method as well.

• 한국산림과학회지
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• 제6권1호
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• pp.37-42
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• 1967

이 시험(試驗) 전남(全南) 광양연습림(光陽演習林)에 있는 약(約) 40여년생(餘年生)의 리기다소나무임분(林分)에서 하계벌(夏季伐)과 동계벌(冬季伐)을 실시(實施)한 다음 조재목(造材木)에 완전박피(完全剝皮), 외피박피(外皮剝皮)(내피부재(內皮付材)) 그리고 무박피처리(無剝皮處里)를 하여 이들이 천연건조(天然乾燥)에 미치는 박피처리(剝皮處理)의 효과(効果)를 구명(究明)하기 위(爲)하여 실시(實施)되었다. 이 시험(試驗)의 결과(結果)를 요약(要約)하면 다음과 같다. (1) 완전박피재(完全剝皮材)는 대체(大體)로 내피부재(內皮付材)나 무박피재(無剝皮材)에 비교(比較)하여 속(速)히 건조(乾燥)하나 건열피해(乾裂被害)를 많이 이르킨다. (2) 하계벌(夏季伐)을 실시(實施)한 완전박피재(完全剝皮材), 내피부재(內皮付材) 및 무박피재(無剝皮材)를 비교(比較)하면 완전박피재(完全剝皮材)와 내피부재(內皮付材) 및 무박피재간(無剝皮材間)에는 차이(差異)가 인정(認定)되어도 내피부재(內皮付材)와 무박피재간(無剝皮材間)에는 차이(差異)가 없다. (3) 동계벌(冬季伐)을 실시(實施)한 경우 내피부재(內皮付材)와 완전박피재간(完全剝皮材間)에는 차이(差異)가 없어도 완전박피재(完全剝皮材) 및 내피부재(內皮付材)와 무박피재간(無剝皮材間)에는 현저(顯著)한 차이(差異)가 있었다. 따라서 내피부재(內皮付材)의 건조효과(乾燥効果)는 완전박피재(完全剝皮材)의 효과(効果)와 같다고 생각(生覺)한다. (4) 이 시험(試驗)에서 하계벌(夏季伐)의 완전박피재(完全剝皮材) 그리고 동계벌(冬季伐)의 내피부재(內皮付材) 및 완전박피재(完全剝皮材)는 모두 4개월(個月) 이내(以內)에 평형함수량(平衡含水量)에 도달(到達)한다고 예상된다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제24권2호
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• pp.207-217
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• 2021

Purpose: This study aimed to investigate the seasonal changes in vitamin D levels in a healthy pediatric population living in mid-latitude East Asian urban areas. Methods: A pediatric population was selected from single secondary hospital visitors. Clinical data and serum vitamin D levels were collected retrospectively. Statistical analyses were performed based on the month of the blood sampling date, subject age, and vitamin D supplementation history. The data were categorized into three subgroups based on serum vitamin D levels-adequate (≥30 ng/mL), insufficient (20-29 ng/mL), and deficient (<20 ng/mL). Results: Of the 481 patients, 172 had vitamin D supplementation history. More than 70% of the total study population had inadequate vitamin D levels (<30 ng/mL). The non-supplemented group and the supplemented group showed significantly uneven monthly distribution of the adequate, insufficient, and deficient subgroups. Only the non-supplemented group showed significantly different average vitamin D levels in the summer months compared to the winter months. In the non-supplemented group, vitamin D levels were the lowest in March, the highest in August and September. Significant relevance was noted between vitamin D supplementation status and vitamin D serum level in February and March. There was no significant difference between different age groups in terms of the distribution of vitamin D levels. Conclusion: Currently-widespread vitamin D replacement methods seem to have some effect on increasing the overall serum vitamin D levels, specifically during late winter when natural serum vitamin D levels plunge. However, they are unable to fully compensate the seasonal fluctuation.

• 한국의류학회지
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• 제31권12호
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• pp.1700-1709
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• 2007

본 연구의 목적은 계절별 의복을 착용하고 쾌적한 상태를 유지하는 동안 불감체중손실과 온열 생리적 요소들간의 관련성을 살펴보는 것이다. 이를 위해 한국의 계절별 실내 환경이 인공기후실에 조성되었고 (봄/가을 환경 기온 평균 22.5, 여름 24.7, 겨울 16.8), 설문조사를 바탕으로 총 26 종의 계절별 한벌의복이 선정되었다(봄/가을 옷 8종, 여름 옷 7종, 겨울 옷 11종). 다섯 명의 젊은 여성이 피험자로 참여하였으며, 결과는 다음과 같다: 1) 불감체중손실(IL)은 봄/가을 의복을 착용한 경우 $19{\pm}5g{\cdot}m^{-2}{\cdot}hr$, 여름 옷 $21{\pm}5g{\cdot}m^{-2}{\cdot}hr$, 겨울 옷 $18{\pm}6g{\cdot}m^{-2}{\cdot}hr$으로, 겨울 환경보다 여름 환경에서 더 컸다(p<.001). 2) 호흡기를 통한 불감수분손실(IWR)은 불감체중손실과 반대의 경향을 보여 주어, 겨울옷을 입은 경우 $6{\pm}1g{\cdot}m^{-2}{\cdot}hr$, 여름 옷을 입은 경우 $5{\pm}1g{\cdot}m^{-2}{\cdot}hr$ 였다(p<.001). 3) 불감수분손실 (IW)에서 호흡기를 통한 불감수분손실이 차지하는 비중은 여름 옷을 착용한 경우 평균 28%, 겨울 의복의 경우 38%였다(p<.001). 4) 쾌적한 상태에서, 산열량 중 불감수분손실이 차지하는 비율은 봄/가을 의복을 착용한 경우 25%, 여름옷의 경우 27%, 겨울옷의 경우 23%였다. 5) 불감체중손실과 의복의 보온력 간, 그리고 불감체중손실과 피복면적 간에는 모두 약한 역상관 관계가 관찰되었다. 6) 불감체중손실은 기온, 기습, 에너지 대사, 환기량, 평균피부온도, 의복내 습도 등의 요소와 유의한 상관을 보였으나, 상관계수들은 모두 0.5 이하였다. 결론적으로, 불감체중손실과 온열 생리 요인들 간에는 약한 상관이 존재했으나, 피험자들이 온열 쾌적을 유지하는 경우 착용한 의복 종류 및 노출 기온에 상관없이 불감체중손실량은 좁은 범위를 유지했다.

• Ocean and Polar Research
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• 제42권2호
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• pp.115-131
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• 2020

The effective range of surface current data observed by high-frequency radar (HFR) operated in the northern coastal area of Jeju Island by Korea Institute of Ocean Science and Technology was estimated and the distribution and variability of the M₂ tidal current of the Jeju Strait was analyzed. To evaluate the HFR data, the M₂ tidal current corrected from 25 hours current data observed by the Korea Hydrographic and Oceanographic Agency (KHOA) was compared with the M₂ tidal current in the Jeju Strait analyzed from the surface currents of HFR. The reliability of HFR data was confirmed by analyzing the characteristics of the tide components of these two data sets, and the effective range of HFR data was estimated through temporal and spatial analysis. The observation periods of HFR used in the analysis were from 2012 to 2014, and it was confirmed that there is a difference in the effective range of HFR data according to the observation time. During the analysis periods, the difference between the M₂ current ellipses from the data of KHOA and the HFR was greater in the eastern than in the western part of the Jeju Strait, and represented a high reliability in the western and central parts of the Jeju Strait. The tidal current of the Jeju Strait analyzed using the HFR data revealed a seasonal variability a relatively weak in summer and a strong in winter, about a 17% fluctuations between the summer and winter based on the length of the semi-major axis of tidal ellipse. Appraisals and results of regarding the characteristics and seasonal variability of the M₂ tidal current in the Jeju Strait using HFR data have not been previously reported, so the results of this study are considered meaningful.

• 한국가축번식학회지
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• 제17권4호
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• pp.311-323
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• 1994

This study was conducted to observe seasonal and individual changes in semen characteristics and sperm freezability, and sperm penetration into zona-free hamster eggs in Korean native goats. Buck response and change in semen characteristics to electrical stimulations was evaluated for four seasons throughout 2 years and percentage of motile sperm and normal apical ridge acrosome was investigated after equilibration and thawing for 4 seasons with 5 bucks. Sperm penetration rate was evaluated for 4 bucks. 1. Probe insertion at depth of 7cm and repeated stimulation for 3 sec was more effective(P<0.05) in buck response and semen collection than those of other conditions. 2. Semen characteristics from electrojaculation was signficantly(P<0.005) higher in spring and fall for semen volume, in spring and summer for sperm concentration and in fall for sperm motility than those in other seasons, respectively. However, there were no differences in total sperm among seasons. 3. Buck response to electrical stimulation showed significant difference(P<0.05) among individuals in all 3 seasons except winter. Significant individual difference in semen volume was only in spring and summer, but there was no indivudual difference in sperm concentration and total sperm in all season. 4. Washing of semen before freezing treatment was greatly(P<0.05) beneficial to sperm motility after thawing, no matter whether ejaculates exhibit egg yolk coagulation or not. 5. Sperm motility after glycerol equilibration was significantly(P<0.05) low in summer semen and motility after thawing was greatly(P<0.05) higher in winter semen than in other seasons. Freezability of unwashed sperm was significantly difference among bucks, but a yearly freezability of washed sperm after chilling and thawing were no differences among bucks and percentage of normal apical ridge acrosome were not different among seasons and bucks. 6. There was no significant difference in sperm motility after thawing between egg yolk levels in summer, although 20% level gave more higher motility than 5% level. 7. In summer, 3.2% glycerol and 3-h equilibration gave greatest percentage(P<0.05) of sperm motility and normal apical ridge acrosome after thawing. 8. Sperm penetration rate into zona-free hamster eggs was not different between bucks and seasons. Overall, it is concluded that to obtain maximum sperm output and successive semen freezing by electrojaculation method, buck selection with good response in all season could be basically considered and that seasonal effect on sperm freezability was more greater than that of individual bucks.

• 한국환경보건학회지
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• 제13권2호
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• pp.25-33
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• 1987

This study was carried out to evaluate student exposures to dust in classroom of middle schools. A total of four schools, such as two in an urban and two in a rural area, were selected for this study. In this study, airborne dust concentrations were measured during a period from July 8 to July 18, 1986. Additional measurements of dust concentrations were conducted from November 4 to 7, 1986 to compare the results by seasonal variation. The results of this study were as follows. 1. Respirable dust concentrations were measured by both filtration method (C mg/m$^3$) and Digital Aerosol Monitor (cpm) to calculate anexchange factor K. K- value was 0.159 as follows. $K=\frac{c}{cpm} = \frac{2.71}{17.09} = 0.159$ 2. In summer when windows were opened, the concentrations of airborne respirable dusts measured by filter sampling method were 0.54-1.37 mg/m$^3$ in the morning and 0.79-1.75 mg/m$^3$ in the afternoon. Thus, higher levels were indicated in the afternoon. Meanwhile, the concentrations of airborne respirable dusts measured in winter were approximately twice as high as those in summer. 3. The highest dust concentrations were determined in School D which is a coeducational school with classroom of concrete floor. Walking roads in School D were not paved and students did not wear indoor-shoes. Dust levels in School D were approximately twice as high as levels in School B. All of the measured dust levels in four schools exceeded Korean Standard for outdoor air, 0.3 mg/m$^3$ for 24 hours. Results by Digital Aerosol Monitor indicated that there was no significant difference in dust levels among grades. The concentration of airborne dusts in the classroom was 1.5-3.0 times higher than that in the hall way. The concentration of airborne dusts during recess was 1.3-1.6 times higher than that during class. In winter, the dust concentrations during clean-up exceeded the permissible exposure limit, 10 mg/m$^3$ (as total dusts), for occupational exposures. 4. The concentrations of total dusts measured in winter were 1.5-2.4 times higher than those of respirable dusts measured simultaneously.

• 한국대기환경학회지
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• 제3권2호
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• pp.46-52
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• 1987

There are many factors such as airtighteness and high density of merchandises or passengers that contaminate indoor air in underground commercial floor. So it is very important to know air quality and quantity of contamination in underground market increasing in number lately. It was from these viewpoints that gaseous pollutants, dusts and mutagenicity of organic compounds extracted from dusts in an underground market were investigatd. Organic ompounds (tar) were extracted by Soxhlet extractor with benzene as a solvent. Mutagenicities of these extracts were evaluated by the preincubation method using Salmonella typhimurium TA 100 and TA 98 strains with and without S9mix. The results obtained were as follows: It seemed to be under the influence of outdoor air that the concentrations of $CO, CO_2, NO, NO_2$ and dusts were higher in winter than summer. The concentration of $CO_2$ was higher in indoor than outdoor, but the concentration of NOx was similar in both sampling areas. Metal contents in dusts attached to the ventilation ducts were as follows showing in order of high concentration : Fe (9000-22000ppm), Zn(1200-2300ppm) and Pb (280-590ppm). The contents of tar were 6-33% of dusts, and higher than those from dusts collected by high volume air sampler. The extracts from dusts attached to the inlet duct exhibited lower mutagenicity than those from dusts attached to the outlet duct. This finding seemed to suggest that mutagenic substances were in creasing in underground. There was no seasonal difference of mutagenicity toward TA 98. Toward TA 100 in the presence of S9mix, the mutagenicity was about 3 fold higher in winter than summer. The mutagenicities of tar extracted from dusts collected by high volume air sampler were different from those attached to the ventilation ducts. The former showed 2-3 fold higher mutagenicity than the latter toward TA 100. However no difference showed between the former and the latter toward TA 98 in the absence of S9mix, but the former was 4-5 fold higher than the latter in the presence of S9mix.

• 대한수의학회지
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• 제40권1호
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• pp.94-100
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• 2000

This study was carried out to determine the causative agent and the epidemiological features of canine dermatitis in Tae-gu, Korea from 1997 to 1998. Specimens of collected from skin lesions were examined mycologically, parasitologically and bacteriologically. In all, 70 dogs of differing ages, gender and living environment were sampled. In mycological examination during this period, pathogenic fungi were cultured from 29(41.3%) of 70 canine specimens. Dermatophytes were cultured from 15(21.4%) and Malassezia pachydermatis were 14(20.0%) of the specimens. The frequent dermatophytes isolated were Microsporum canis (12.9%). Trichophyton mentagrophytes (4.3%), T rubrum (2.9%), T raubitschekii and M gypseum (each 1.4%). There was a high proportion of positive cultures from dogs less than 1 year and over than 3 years of age, and in some long haired breeds, but there was no significant difference between the sexes, and the living environments. Although dermatophytes were more frequently isolated in spring and winter, no significant difference was detected in the seasonal distribution of the canine dermatophytosis. Out of 70 dogs, dermatitis ectoparasites(27.1%; Demodex canis 18.6% and Sarcoptes scabie 8.6%) and bacterial pyoderma(40.4%) were diagnosed. Demodex canis and Sarcoptes scabie were common canine ectoparasites, with a higher incidence in short haired breeds and in summer and winter. Bacterial pyoderma was a higher incidence in long haired breeds, and in summer. In the pathogenic agents isolated from 57 dogs(81.4%), single infection rate was 66.7%(38 dogs) and mixed infection rate was, 35.1%(19 dogs). In the majority of mixed infection cases, Gram positive cocci and Malassezia pachydermatis (in 5 cases, 8.8%), as well as ectoparasites(in 6 cases, 10.5%) were demonstrated simultaneously.