• Wind and Structures
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• 제36권1호
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• pp.41-60
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• 2023

The effect of cladding panel size on the size reduction factor (SRF) of extreme area-averaging wind pressure (EAWP) on the facades of a high-rise building is often ignored in previous studies. Based on wind tunnel tests, this study investigated the horizontal and vertical correlations of wind pressure on the facade claddings of square-section high-rise buildings. Then, the influencing parameters on the SRF of the EAWP on the cladding panels were analyzed, which were the panel area, panel width, panel length and building width. The results show clear regional distinctions in the correlation of wind pressures on the building facades and the rules of the horizontal and vertical correlations are remarkably different, which causes the cladding size ratio to impact the SRF significantly. Therefore, this study suggests the use of the non-dimensional comprehensive size parameter b^𝜶h^1-𝜶/B (𝜶 is the fitting parameter) determined by the cladding panel horizontal size b, cladding panel vertical size h and the building width B rather than the cladding panel area to describe the variation of the EAWP. Finally, some empirical formula for the SRF of the EAWP on the cladding of a high-rise building is proposed with the nondimensional comprehensive size parameter.

• 생태와환경
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• 제36권4호통권105호
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• pp.403-412
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• 2003

전남 주암호에서의 식물플랑크톤 동태를 파악하기 위해 2003년 2월부터 10월까지 식물플랑크톤생체량 (클로로필 a)의 크기별 시 ${\cdot}$ 공간적 변동과 제반 환경요인에 대해 조사하였다. 본 논문에서는 주암호와 같은 담수호에서 식물플랑크톤의 크기 구조가 계절적, 공간적으로 어떻게 변화하고 그러한 변화 속에서 물리적 요인들이 어떤 영향을 미치는지 회귀분석을 통해 파악하고자 하였다. 식물플랑크톤 (클로로필 a)은 세 그룹 즉, 대형 (micro-size > 20 ${\mu}m$), 소형 (nano-size 3-20 ${\mu}m$) 마지막으로 초소형 (pico-size, < 3 ${\mu}m$)으로 구분했다. 물리적 특성 파악을 위해 수온, 광소멸계수, PAR (photosynthetically active radiation), 수중 탁도등도 동시에 측정하였다. 최대치의 클로로필 a 는 2003년 하류지역에서는 4월에 상류지역에서는 10월에 발생하였다. 식물플랑크톤의 대번성기에는 대부분 세포크기가 큰 대형 (micro-size)식물플랑크톤이 우세하였다. 주암호의 크기별 식물플랑크톤의 변동에 영향을 미칠 수 있는 물리적 특성들에 대해 논의하였다.

• 한국임상수의학회지
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• 제28권4호
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• pp.422-426
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• 2011

For a national survey in which wide geographic region or an entire country is targeted, multi-stage sampling approach is widely used to overcome the problem of simple random sampling, to consider both herd- and animallevel factors associated with disease occurrence, and to adjust clustering effect of disease in the population in the calculation of sample size. The aim of this study was to establish sample size for estimating bovine tuberculosis (TB) in Korea using stratified two-stage sampling design. The sample size was determined by taking into account the possible clustering of TB-infected animals on individual herds to increase the reliability of survey results. In this study, the country was stratified into nine provinces (administrative unit) and herd, the primary sampling unit, was considered as a cluster. For all analyses, design effect of 2, between-cluster prevalence of 50% to yield maximum sample size, and mean herd size of 65 were assumed due to lack of information available. Using a two-stage sampling scheme, the number of cattle sampled per herd was 65 cattle, regardless of confidence level, prevalence, and mean herd size examined. Number of clusters to be sampled at a 95% level of confidence was estimated to be 296, 74, 33, 19, 12, and 9 for desired precision of 0.01, 0.02, 0.03, 0.04, 0.05, and 0.06, respectively. Therefore, the total sample size with a 95% confidence level was 172,872, 43,218, 19,224, 10,818, 6,930, and 4,806 for desired precision ranging from 0.01 to 0.06. The sample size was increased with desired precision and design effect. In a situation where the number of cattle sampled per herd is fixed ranging from 5 to 40 with a 5-head interval, total sample size with a 95% confidence level was estimated to be 6,480, 10,080, 13,770, 17,280, 20.925, 24,570, 28,350, and 31,680, respectively. The percent increase in total sample size resulting from the use of intra-cluster correlation coefficient of 0.3 was 22.2, 32.1, 36.3, 39.6, 41.9, 42.9, 42,2, and 44.3%, respectively in comparison to the use of coefficient of 0.2.

• 한국융합학회논문지
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• 제11권6호
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• pp.259-268
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• 2020

본 연구는 팬덤활동에 연구들을 총체적·계량적으로 분석한 후 팬덤활동의 구성 유형과 효과를 검증하는 데 목적이 있다. 연구결과는 다음과 같다. 효과크기 비교 시 사회경제분야 관련 변인이 가장 큰 효과크기를 보였고, 다음은 개인 행동, 개인심리로 효과크기가 나타났다. 다음으로 팬덤활동의 영향요인에서 긍정적 변인의 효과크기가 중간 수준의 효과크기를 나타내고 부정적 변인의 효과크기가 낮은 수준의 효과크기를 보이는 것으로 나타났다. 또한 팬덤 형태 내 분석에서는 팬덤이 아이돌 팬덤일 때 가장 효과크기가 크고, 그다음은 스포츠스타, 배우 순이었다. 연구 대상자 중 효과크기는 대학생, 전체, 성인, 중고등학생, 중학생 순으로 나타났다. 한편 나라별 구분에 따른 분석을 실시한 결과 중국이 가장 효과크기가 높고, 유사하게 미국의 경우도 높은 수준의 효과크기가 있었다. 반면 대한민국의 경우 효과크기가 나타나 낮은 수준의 효과크기를 보였다.

• 한국분말재료학회지
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• 제11권6호
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• pp.493-502
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• 2004

In this study, nano-sized indium oxide powder with the average particle size below 100 nm is fab-ricated from the indium chloride solution by the spray pyrolysis process. The effects of the reaction temperature, the concentration of raw material solution and the inlet speed of solution on the properties of powder were studied. As the reaction temperature increased from 850 to $1000^{\circ}C$, the average particle size of produced powder increased from 30 to 100 nm, and microstructure became more solid, the particle size distribution was more irregular, the intensity of a XRD peak increased and specific surface area decreased. As the indium concentration of the raw material solution increased from 40 to 350 g/l, the average particle size of the powder gradually increased from 20 to 60 nm, yet the particle size distribution appeared more irregular, the intensity of a XRD peak increased and spe-cific surface area decreased. As the inlet speed of solution increased from 2 to 5 cc/min., the average particle size of the powder decreased and the particle size distribution became more homogeneous. In case of the inlet speed of 10 cc/min, the average particle size was larger and the particle size distribution was much irregular compared with the inlet speed of 5 cc/min. As the inlet speed of solution was 50 cc/min, the average particle size was smaller and microstructure of the powder was less solid compared with the inlet speed of 10 cc/min. The intensity of a XRD peak and the variation of specific area of the powder had the same tendency with the variation of the average par-ticle size.

• Journal of Korean Society for Atmospheric Environment
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• 제17권E1호
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• pp.1-7
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• 2001

The elemental characteristics of atmospheric aerosols were investigated as a function of particle size and water solubility. The aerosol particles were samples at 12 individual size ranges between 0.01 and 30㎛. Collected aerosol particles were separated into both soluble and insoluble components. The concentrations of 15 elements in both components were determined by a PIXE analysis using a 2.0 MeV-proton beam. In general, the mass size distribution of particulate matter was represented as a bimodal distribution. The maximum rations of S in July and December were 5.5 and 3.8 %, and they appeared in the size range of 0.47∼1.17㎛(stage No. 6 or 7) . The ratios of a S at non-separated size were 3.1 and 2.2 % in July and December, respectively, On the other hand, the maximum rations of Si in July and December were 7.0 and 5.4% and they appeared in the size range of 5.1∼30㎛(stage No. 0∼2). The ratios of Si at the non-separated size were 2.1 and 1.8% in July and December, respectively, The mass diameter of 12 elements ranged between 0.59㎛ of S and 3.20 of Fe. More than 90% of atmospheric aerosols consisted of the light elements such as C, N, O, H and Al. The soluble component was dominant in the smaller size range and the insoluble component in the larger size range. Large portions of Si. Ti and Fe existed in insoluble state. By contrast, S, Cl, Ca, Zn and Br were dissolved in water.

• Nutrition Research and Practice
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• 제6권2호
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• pp.120-125
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• 2012

The aim of this study was to investigate the influencing factors that characterize low density lipoprotein (LDL) phenotype and the levels of LDL particle size in healthy Korean women. In 57 healthy Korean women (mean age, $57.4{\pm}13.1$ yrs), anthropometric and biochemical parameters such as lipid profiles and LDL particle size were measured. Dietary intake was estimated by a developed semi-quantitative food frequency questionnaire. The study subjects were divided into two groups: LDL phenotype A (mean size: $269.7{\AA}$, n = 44) and LDL phenotype B (mean size: $248.2{\AA}$, n = 13). Basic characteristics were not significantly different between the two groups. The phenotype B group had a higher body mass index, higher serum levels of triglyceride, total-cholesterol, LDL-cholesterol, apolipoprotein (apo)B, and apoCIII but lower levels of high density lipoprotein (HDL)-cholesterol and LDL particle size than those of the phenotype A group. LDL particle size was negatively correlated with serum levels of triglyceride (r = -0.732, $P$ < 0.001), total-cholesterol, apoB, and apoCIII, as well as carbohydrate intake (%En) and positively correlated with serum levels of HDL-cholesterol and ApoA1 and fat intake (%En). A stepwise multiple linear regression analysis revealed that carbohydrate intake (%En) and serum triglyceride levels were the primary factors influencing LDL particle size ($P$ < 0.001, $R^2$ = 0.577). This result confirmed that LDL particle size was closely correlated with circulating triglycerides and demonstrated that particle size is significantly associated with dietary carbohydrate in Korean women.

• Journal of Nutrition and Health
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• 제40권1호
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• pp.89-96
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• 2007

This study was performed to weigh the average meal portion sizes served for preschoolers by kindergarten teacher. The subjects were 53 teachers from 8 kindergartens, which are random sampled by meal service number. Using the weighing method assessed the meal portion sizes of food items at lunch. The data was complied by performing $\chi^2-test$ using SPSS WIN 11.0. The result was as followed: 98.0% of teacher agreed with the meal service because of 'better food habit and table etiquette'(68.0%), 'health promotion with balanced diet'(22.0%), 'owing to extending school time'(6.0%) and 'demand of parents'(2.0%). Preschooler eat lunch at class (84.9%) and meal serving size was decided by teacher (79.2%). Teachers thought that they know very well about portion size 3.8%, 96.2% of teacher thought that they don't know much about portion size. Portion size were not significantly different by food tray types but there was much different (almost 100%) compared with minimum and maximum within dishes. Most average portion size was not met dietary reference intake except cooked rice, soups and fish cutlet. Working experience effected on portion size. More served, more working experienced of teacher. For example Bulgogi was served 26.8 g by teacher who has over 6 years working experience compared with 2-6 years (20.4 g) and less than 2 years (17.1 g) (p < 0.01). Spinach portion size was significantly different by teacher's working experience (p < 0.01). Portion size were not significantly different by preschooler's age. The reference of dietary for preschooler was different by age, but teachers served meal by their experience. According to the results of this study, it is necessary to educate meal portion size for kindergarten teacher who take charge in meal serving. To provide guidance to teacher about reasonable portion sizes for preschoolers, teacher need to take nutrition education about meal service and child nutrition in college. This study would be useful to those who plan meals for preschoolers and to researchers studying dietary intakes of preschooler.

• 한국재료학회지
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• 제21권4호
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• pp.187-191
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• 2011

Prior austenite grain size plays an important role in the production of high strength hot-rolled steel. This study investigated the effect of Ti and C contents on the precipitates and prior austenite grain size. Steel with no Ti solutes had prior austenite grain size of about 620 ${\mu}m$. The addition of Ti ~ 0.03 wt.% and 0.11 wt.% reduced the prior austenite grain size to 180 ${\mu}m$ and 120 ${\mu}m$, respectively. The amount of Ti required to significantly decrease the prior austenite grain size was in the range of 0.03 wt.%. However, the amount of carbon required to significantly decrease the prior austenite grain size was not present from 0.04 wt.% to 0.12 wt.%. Oxides of Ti ($Ti_2O_3$) were observed as the Ti content increased to 0.03 wt.%. The specimen containing 0.11 wt.% of Ti exhibited the complex carbides of (Ti, Nb) C. The formation of Ti precipitates was critical to reduce the prior austenite grain size. Furthermore, the consistency of prior austenite grain size increased as the carbon and Ti contents increased. During the reheating process of hot-rolled steel, the most critical factor for controlling the prior austenite grain size seems to be the presence of Ti precipitates.

• 농업과학연구
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• 제16권2호
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• pp.138-151
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• 1989

In order to find the effects of seed size on the early seedling growth and yield of soybean, three soybean cultivars in Korea were investigated. Seed size was classified into large and small according to the weight and planted in pots(1/5000a) and in the field. Three soybean cultivars respresenting large, medium and small grains were Hwangkeum-kong, Kwangkyo and Bangsa-kong respectively. These cultivars were planted on June 20, 1987. 1. The plant height, stem diameter, root length and leaf area index(LAI) of the seed with large size seemed larger than the seed with small size regardless of cultivars. 2. The fresh and dry weight were different depending upon the grain sizes. The large grain had heavier fresh and dry weight than the small grains. 3. The protein consumption rate of the cotyledon of Bangsa-kong with small grain size was faster than the Hwangkeum-kong with large grain size. 4. The stem length, stem diameter and number of main stem node of the seed with large size seemed larger than the seed with small size. Large grains of Hwangkeum-kong were the highest in the number of branch node and number of node. 5. The number of pods and grains per plant of Bangsa-kong with small grain size was larger than the Kwangkyo with large grain size. 6. The yield per 10a for Hwangkeum-kong, Hwangkyo and Bangsa-kong were 226.3kg, 193.0kg and 192.8kg, respectively and they were all statistically different. The yield increases of large grains over small grains in the Hwangkeum-kong, Kwangkyo, and Bangsa-kong were 7.4%, 8.0% and 9.2%, respectively.