• 한국응용과학기술학회지
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• 제26권2호
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• pp.224-231
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• 2009

Techniques measuring Maxwell displacement current (MDC) and LB films surface measuring technique have been applied to the study of monolayers of polyamic acid containing azobenzene. MDCs was generated from monolayers on the water surface by monolayer compression and expansion. It was generated when the area per molecule was about $103{\AA}^2\;and\;78{\AA}^2$ just before the initial rise of the surface pressure during the 1st and 2nd mixed monolayer compressions cycle, respectively. It was the maximum of MDCs appeared at the molecular area just before the initial rise of surface pressure in compression cycles, and we have found that the increase of aggregations causes the noticeable increase of the surface roughness.

• 아시안잔디학회지
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• 제10권2호
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• pp.117-124
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• 1996

One new cellular slime mold, Dicivostelium valenstemmun sp. n. Shim et Chang, is isolated from the fermentation layer of soils in the cool temperate forests of Surak mountain, Korea. This species has the sori and sorophore yellow-pigmented, and sparse or irregular branches. And it is characterized by tall and robust sorocarps, well-form basal disks, mucoroides-type aggregations and large spores. This species has sorophores gradually tapering from bases to tips, simple capi- tate sorophore tips and conical bases. When prostrates on the plates, it has sparsely clavate bases. Spores are considerably large, 6.8~9.9 x 3.4~5.1 $\mu$m(avg. 8.5 x 4.1 $\mu$m), L /W index l.84~2.43(avg. 2.07) without polar granules. Key words: Diccyostelium valeustemmum, Cool temperate forests, Surak mountain.

• Bulletin of the Korean Chemical Society
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• 제29권1호
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• pp.104-110
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• 2008

Poly(allylamine) hydrochloride is a weak cationic polyelectrolyte that exhibits different aggregation properties at different solution pH values and aging times. Specifically, after several days aging in a pH 3 buffer, less than 1 mg/mL poly(allylamine) hydrochloride became turbid, and the hydrodynamic radius increased with a single diffusion mode. However, the hydrodynamic radius did not change at high concentrations. The dynamic processes of polymer aggregations at different pH values were verified by a light scattering and zeta-potential apparatus. The major interaction was caused by the capturing of counterions by the polyelectrolyte, which generates electrostatic, hydrophobic and cation-p interactions.

• The Korean Journal of Ecology
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• 제18권4호
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• pp.463-470
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• 1995

Anoplocnemis dallasi Kiritchencho is a sap-sucker which feeds on tips of amorpha fruticosa Linne in Korea. A. Dallasi had one generation a year and overwintered as the young adult stage. Most overwintered survivors emerged in early-mid May to late May. Known host plants were reviewed, and new host records were added. Females mainly laid eggs in linear single chain masses on leaves of Miscanthus sinensis var. purpurascens. Nymphs (except the non-feeding first instars) fed on young shoots. First instar nymphs clustered on leaves or shoots where they hatched, and, if disturbed, reformed aggregations soon. The second to the fifth instar nymphs migrate to the upper part of the shoot and congreagate on a partly expanded leaf. New adults firstly appeared in late August, remained on A.fruticosa, host plant, and fed on until mid October. The duration and survivorship curve, in laboratory rearing, of the egg and each nymphal stadium was determined.

• Journal of Communications and Networks
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• 제14권4호
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• pp.443-450
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• 2012

As for cluster-based wireless sensor networks (WSNs), cluster lifetime is one of the most important subjects in recent researches. Besides reducing the energy consumptions of the clusters, it is necessary to make the clusters achieve equal lifetimes so that the whole network can survive longer. In this paper, we focus on the cluster lifetimes in multi-hop WSNs with cooperative multi-input single-output scheme. With a simplified model of multi-hop WSNs, we change the transmission schemes, the sizes and transmission distances of clusters to investigate their effects on the cluster lifetimes. Furthermore, linear and uniform data aggregations are considered in our model. As a result, we analyze the cluster lifetimes in different situations and discuss the requirements on the sizes and transmission distances of clusters for equal lifetimes.

• The Journal of the Acoustical Society of Korea
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• 제25권4E호
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• pp.159-165
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• 2006

Human, horse and rat bloods in a cylindrical chamber where flow was controlled by a stirring magnet were used for studying red blood cell aggregation. Ultrasound backscattered powers from blood were obtained from the backscattered signals measured by a 5 MHz focused transducer in a pulse-echo setup. The experimental results showed the differences in red blood cell (RBC) aggregation tendency among the three mammalian species with an order of horse > human > rat. The ultrasound backscattered power decreased with stirring speed in human and horse blood, but no variations were observed in rat blood. Sudden flow stoppage led to the slow increase of the backscattered power for human and horse blood. There was no self-aggregation tendency in rat blood. The enveloped echo images showed the spatial and temporal variations of RBC aggregations in the cylindrical chamber. These observations from the different mammalian species may give a better understanding of the mechanism of RBC aggregation.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2003년도 추계학술대회논문집
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• pp.3-8
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• 2003

Census data are usually provided at an aggregated level. However, the aggregated data are essentially arbitrary geographical areas. The areal units used to report census data have no natural or meaningful geographical identity. Unfortunately, this means that analyses of these area aggregations may be conditional upon the set of zones, which are presented. This effect is known as the modifiable areal unit problem (MAUP) and has two related aspects. First, scale effect is the variation in numerical results that occurs due to the number of zones used in an analysis. Second, results may also differ between different ways of aggregating exactly the same data to the same scale; this may be called the aggregation effect (Openshaw, 1984). This study aims to provide a practical tool for the study of MAUP. I have created a set of 91 areal units based on 280 basic units in Nonhyun-2 dong to solve zoning problem and scale problem. We can easily recognize the importance of areal classification as statistics were different according to areal classification.

• 한국식품위생안전성학회지
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• 제11권4호
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• pp.273-276
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• 1996

Platelets serve many biological functions, including a major role in the haemostatic process. But platelets also play a crucial role in the formation of arterial thrombosis, arteriosclerosis and other pathologic processes. Thus, there have been many studies to develop new antiplatelet agents from foods and plants for decades. Inthis study, inhibitory effects of the oriental onion (Allium fistulosum) on platelet aggregation were investigated using platelet rich plasma (PRP). Water extracts of oriental onion was separated into two fractions (Fraction I and Fraction II) by Sephadex G-150 column. Platelet aggregations were inhibited by total water extracts as well as Fraction I and II. IC50 value of Fraction I was much lower than that of Fraction II. Inhibitory effects of total water extracts of oriental onion on ATP release by PRP were also observed.

• 한국식품조리과학회지
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• 제29권6호
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• pp.647-652
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• 2013

Solubility profiles of zein and carotenoid in aqueous ethanol were studied. Zein showed minimum turbidity at the aqueous ethanol concentration of 87-92%, indicating least aggregations between protein molecules. Solubilities of zein and carotenoid increased linearly with the content of yellow zein up to 20% in the aqueous ethanol range of 60-95% tested. At room temperature of $20^{\circ}C$, zein showed maximum solubility in broad ethanol concentration ranges of 60-95%, while that for carotenoid was somewhat narrower with ethanol concentration range of 85-95%. However, at incubation temperature of $-20^{\circ}C$, solubilities of both carotenoid and zein were lowered, with dramatic reduction being exhibited at aqueous ethanol concentration of 60% for both compounds, while substantial reduction in solubility was shown at 95% ethanol by zein only. Zein was practically insoluble in absolute ethanol, regardless of temperature range tested, while carotenoid remained largely soluble, though there was pronounced decrease in solubility at the subfreezing temperature.

• Natural Product Sciences
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• 제8권2호
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• pp.71-75
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• 2002

As apart of our continuing search for antistroke agents from the herbal medicinal resources, we examined in vitro, ex vivo and in vivo the possibility of Sunghyangjunggisan and its ingradients as a novel antithrombotic agent. In vitro ADP- and collagen-induced rat platelet aggregations were potently inhibited by Arisaematis Rhizoma, Cinnamomi Cortex and Zingiberis Rhizoma in a dose-dependent manner, but not by Sunghyangjunggisan. However, Sunghyangjunggisan significantly inhibited ex vivo rat platelet aggregation. Arisaematis Rhizoma, Atractylodis Rhizoma Alba, and Pinelliae Rhizoma also significantly inhibited ex vivo rat platelet aggregation. Sunghyangjunggisan, Alpiniae Fructus and Zingiberis Rhizoma showed significant protection from death due to pulmonary thrombosis in mice. Therefore, Sunghyangjunggisan can express the antithrombotic action, when it is orally administered.