• 한국수산과학회지
• /
• 제29권3호
• /
• pp.386-392
• /
• 1996

A numerical method based on genetic algorithms was introduced to characterize the grain-size distribution more effectively. This technique was proved significant particularly for multimodal size distributions, as was verified for samples from Korea Strait continental shelf. Sediment samples collected from the Korea Strait continental shelf revealed that $96\%$ of the grain-size distributions were multimodal. Therefore, the use of grain-size parameters was not the ideal method. As an alternative method, the decomposition of sue curves into elementary normal component curves was used. Means and standard deviations of 593 decomposed normal components were calculated by a numerical method from 268 size curves of Korea Strait sediments. The mean values of decomposed normal components showed peaks at $1\~3\phi\;and\;7\~9\phi$ size classes. The plot of mean and standard deviation values of the coarse fraction normal components on the map showed a characteristic areal distribution. The characteristic distribution was found to derive from underlying Pleistocene sediment on the basis of sea bottom geologic distribution of the area. The method of decomposition into normal components was found to be more effective than the analysis using traditional grain-size parameters in investigation of multimodal size distribution of Korea Strait shelf sediment.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
• /
• pp.594-596
• /
• 2003

Due to the fact that the composition and variability of aerosols is considered rather complex, it is difficult to employ a simple and straightforward physical model in calculating the aerosol size distribution in the absence of actual data. This complicates the already difficult retrieval of various atmospheric parameters from remotely sensed data. Thus, the main purpose of this study is trying to find an effective aerosol size coefficient that is stable, and can depict the particle size distribution. This paper also attempts to construct an 'effective aerosol size coefficient' database for each respective season, where it can quickly and effectively supply pertinent information of the atmosphere's opacity.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
• /
• pp.702-703
• /
• 2006

The particle size distribution and shape are among the important parameters for characterisation of quality of metal powders. Specific material properties such as ability to flow, reactivity as well as compressibility and its hardening potentials hence the most important characteristics of sintered metals - are determined by the size distribution and shape. The correct particle size distribution and particle shape information are the key to best product quality in atomisation processes of aluminium, milling of pure metals and other processes. This paper presents state-of-the-art technology for characterization of particle size distribution and shape.

• 복식문화연구
• /
• 제8권4호
• /
• pp.549-561
• /
• 2000

The purpose of this study was to survey and analyze the age classification of women customers as a target market and sizes on a label that were actually produced by each brand in Korean national brands ; they were classified into size for bodice and bottom, and compared with the distribution of national data of women's body measurement. They were analyzed and classified by brand groups of 'miss', 'missy', 'Mrs.'and 'madam', The results were ; 1) It was found that recent products for ready-made for women's clothes tend to be designed with target to the measured ages classified by the range of five or ten years. The main practice was that for 'miss'brand group the age range was of five years, and for 'missy'brand group, ten years. And for 'Mrs'and 'madam'brand groups, it was of 15 or 20 years. So that, it is necessary to design their clothes based on their features of body considering the intervals of age. 2) 'Mrs'and 'madam'groups were most remarkable for their distribution into a vast range of sizes for three control dimensions and waist girth size when compared to 'miss'and 'missy'groups. The distribution of brand size had no relation with that of body measurement, and in particular, none was produced for short height size between 145 and 150 ㎝. For tall height size between 175 and 180 ㎝, many brand sizes were distributed while body measurement was few. It means that distribution of brand size was different from real distribution of body measurement was few. It means that distribution of brand size was different from real distribution of body measurement as a result that the larger the bust girth in such cases over 160 ㎝, the larger the size of hip girth. Even as for the height 155 and 160 ㎝ in which body measurement is concentrated, there were many problems because while sizes of 'large'bust girth and 'small'hip girth had a large distribution, their clothes were not produced.

• 한국입자에어로졸학회지
• /
• 제19권4호
• /
• pp.155-164
• /
• 2023

APS (Aerodynamic Particle Sizer) and OPC (Optical Particle Counter) have been widely used to real-time measurement of indoor and outdoor aerosols. The APS measures the size distribution based on an aerodynamic diameter, while the OPC uses optical diameter to measure the size distribution of aerosols. Since obtaining a size distribution based on aerodynamic diameter is important to understand aerosol characteristics, lots of researcher had been developed experimental equations which can convert optical diameter into aerodynamic diameter. However, previous studies have conducted repeated experiments on particles having a single diameter. In this study, an experimental method of converting optical diameter into aerodynamic diameter through a single experiment was presented. The collection efficiencies of an axial cyclone were measured using APS and OPC at the same time, and the correlation equation between aerodynamic diameter and optical diameter was driven through a theoretical model. Using the proposed method, the size distribution of NaCl particles measured by OPC showed a high correlation with the size distribution obtained by APS (0.93 of R-squared value). In the tests conducted on ISO A1, A2, and A4 test particles, the converted OPC size distribution tended to be similar to the APS size distribution, and for each of test particles (ISO A1, A2, and A4), the R-squared values for the APS particle size distribution were 0.75, 0.86, and 0.89, respectively.

• 산업경영시스템학회지
• /
• 제26권1호
• /
• pp.85-94
• /
• 2003

In this paper, a mathematical model is developed for economic design of multi-stage distribution system that consists of factory, central distribution centers, local distribution centers and retailers. The retailers are supplied products from different stage suppliers according to order size. The retailers are supplied products from factory if demand amount is large, central distribution center if medium, local distribution center if small. The economic design is to determine the economic size of facility factors that consist of distribution system. The cost factors are transportation cost from supply places to demand places, handling cost at distribution centers and inventory holding cost at retailers. It is to determine the transportation route of each retailer, the size and number of the vehicle at factory and distribution centers, the handling amount at distribution centers in order to minimize the total costs. The mathematical model is represented, the solution procedure is developed, and a numerical example is shown.

• 한국수자원학회논문집
• /
• 제53권10호
• /
• pp.917-928
• /
• 2020

본 연구는 점착성 부유사의 입도분포에 적합한 이론적 확률분포형을 찾는 것을 목적으로 수행되었다. 유의수준 5%에 대해 적합도 검정을 수행한 결과, 실험실 실험자료와 현장실험 자료에서 측정된 플럭입도분포는 다른 결과를 나타냈다. 현장실험으로부터 얻어진 표본자료의 경우 왼쪽으로 치우친 지수분포의 형태를 나타내며, Gamma 분포가 가장 우수하였다. 실험실실험 자료의 경우 표본자료가 양의 왜도를 가지며 GEV 분포가 가장 적합하였다. 많은 연구에서 점착성 유사의 입도분포로 가정되는 2매개변수 Lognormal 분포의 경우 현장실험 자료와 실험실실험 자료 모두 적합하지 않았으며, 위치매개변수를 추가하여 3매개변수 Lognormal 분포 적용 시 점착성 유사의 입도분포를 모사할 수 있는 것으로 나타났다.

• 펄프종이기술
• /
• 제33권1호
• /
• pp.53-61
• /
• 2001

This study was carried out to evaluate the effect of coating pigments on the printability by investigating the pore structure of casting layer such as the number, size and distribution of pores and the pore rate. The coating structure was mainly determined by the interaction between pigment and binder. It means that the structure of pores was chiefly affected by the shape and size distribution of pigments and their packing rate. The physical properties of pore have close relationships with ink set-off, the speed of ink penetration and printing gloss. The results suggested that the rate and number of pores were greatly affected by the particle size distribution and shape of pigments. The rate of pore increased with the reduction of particle size distribution of pigments. Calcite was effective to improve greatly the printability of coated paper.

• 한국재료학회지
• /
• 제23권9호
• /
• pp.489-494
• /
• 2013

In this study, by using nickel chloride solution as a raw material, a nano-sized nickel oxide powder with an average particle size below 50 nm was produced by spray pyrolysis reaction. A spray pyrolysis system was specially designed and built for this study. The influence of nozzle tip size on the properties of the produced powder was examined. When the nozzle tip size was 1 mm, the particle size distribution was more uniform than when other nozzle tip sizes were used and the average particle size of the powder was about 15 nm. When the nozzle tip size increases to 2 mm, the average particle size increases to roughly 20 nm, and the particle size distribution becomes more uneven. When the tip size increases to 3 mm, particles with an average size of 25 nm and equal to or less than 10 nm coexist and the particle size distribution becomes much more uneven. When the tip size increases to 5 mm, large particles with average size of 50 nm partially exist, mostly consisting of minute particles with average sizes in the range of 15~25 nm. When the tip size increases from 1 mm to 2 mm, the XRD peak intensities greatly increase while the specific surface area decreases. When the tip size increases to 3 mm, the XRD peak intensities decrease while the specific surface area increases. When the tip size increases to 5 mm, the XRD peak intensities increase again while the specific surface area decreases.

• 폴리머
• /
• 제28권2호
• /
• pp.170-176
• /
• 2004

반응조건에 따른 실록산으로 코팅된 마그네타이트 나노입자의 크기 및 분포를 동적광산란을 이용하여 조사하였다. FT-IR로부터 마그네타이트의 표면에 히드록시기가 존재함을 확인하였고 이 히드록시기는 코팅된 실록산의 실란올과 수소결합을 이루고 있음이 확인되었다. 제조된 나노입자의 크기는 반응온도가 증가함에 따라 입자크기는 증가하였고 단량체 함량과 교반 속도의 증가에 따라서는 감소하였다. 입자 크기 분포는 반응조건에 따라서 약간의 변화는 있지만 전체적으로 14∼41nm 크기의 범위를 나타냈다. 제조된 마그네타이트의 자성특성은 vibrating sample magnetometer를 이용하여 초상자성임이 확인되었고 실록산으로 코팅된 나노입자 역시 초상자성을 나타냄을 확인하였다. 반응조건에 따라서는 반응온도가 증가할수록 포화자화강도는 증가하였고 단량체 함량과 교반 속도가 증가함에 따라서 포화자화강도가 감소하는 것을 나타내었다.