• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.213-219
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• 2012

Recently, we are simultaneously exposed by various electromagnetic sources due to an increase of mobile communication services. However, EMF(Electric, Magnetic and Electromagnetic Field) study has been performed mainly about only single frequency. The objective of this paper is to develop an multiple-frequency exposure system for in vitro experiment. The exposure unit for in vitro experiments was designed by radial transmission line type to get broadband characteristics to generate signals of CDMA at 836.5 MHz and WCDMA at 1950 MHz frequency simultaneously. The modulated signals were delivered to the conical antenna through amplifier, digital attenuator and RF combiner. SAR values were obtained by the averaged values of 3 measured values at 9 points in petri dish using the fiber optic temperature probe. The measured return loss was under -15 dB. For 1 W input power, the mean value and standard deviation of SAR were $0.105{\pm}0.019$ for the CDMA frequency and $0.262{\pm}0.055$ for the WCDMA frequency.

• Korean Journal of Environment and Ecology
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• v.22 no.4
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• pp.427-434
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• 2008

The studies of seven individuals of Asiatic black bears were carried out with radio telemetry from October 2004 to December 2006 in Jirisan National Park. They were attached radio-transmitter and calculated by the 95%MCP and fixed kernel method(95%, 50%). As a result, Mean annual home ranges for female and male asiatic black bears were 71.66$km^2$ and 90.20$km^2$. The seasonal home ranges were calculated 19.81$km^2$ for females and 33.47$km^2$ for males in spring, 30.48$km^2$ for females and 20.26$km^2$ for males in summer, 22.63$km^2$ for females and 23.23$km^2$ for males in autumn and 0.22$km^2$ for females and 0.78$km^2$ for males in winter(F=4.193, P<0.05). The degree of home range overlapped 38%, 12.5% among females, 22.4% among males. Mean elevation of seven bears was 744$\pm$236m in spring, 682$\pm$253m in summer, 937$\pm$218m in fall and 975$\pm$137m in winter(F=8.526, P<0.001). It is assumed that home range sizes and location were closely correlated to environmental characteristics of the habitats and the seasonal variation of home-range was related to distribution of food sources.

• Journal of The Korean Astronomical Society
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• v.48 no.2
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• pp.125-137
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• 2015

We report results of the performance evaluation of a new hardware correlator in Korea, the Daejeon correlator, developed by the Korea Astronomy and Space Science Institute (KASI) and the National Astronomical Observatory of Japan (NAOJ). We conduct Very Long Baseline Interferometry (VLBI) observations at 22 GHz with the Korean VLBI Network (KVN) in Korea and the VLBI Exploration of Radio Astrometry (VERA) in Japan, and correlated the aquired data with the Daejeon correlator. For evaluating the performance of the new hardware correlator, we compare the correlation outputs from the Daejeon correlator for KVN observations with those from a software correlator, the Distributed FX (DiFX). We investigate the correlated flux densities and brightness distributions of extragalactic compact radio sources. The comparison of the two correlator outputs shows that they are consistent with each other within < 8%, which is comparable with the amplitude calibration uncertainties of KVN observations at 22 GHz. We also find that the 8% difference in flux density is caused mainly by (a) the difference in the way of fringe phase tracking between the DiFX software correlator and the Daejeon hardware correlator, and (b) an unusual pattern (a double-layer pattern) of the amplitude correlation output from the Daejeon correlator. The visibility amplitude loss by the double-layer pattern is as small as 3%. We conclude that the new hardware correlator produces reasonable correlation outputs for continuum observations, which are consistent with the outputs from the DiFX software correlator.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.79-82
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• 2015

The physical and chemical properties of prestellar cores, especially massive ones, are still far from being well understood due to the lack of a large sample. The low dust temperature (< 14 K) of Planck cold clumps makes them promising candidates for prestellar objects or for sources at the very initial stages of protostellar collapse. We have been conducting a series of observations toward Planck cold clumps (PCCs) with ground-based radio telescopes. In general, when compared with other star forming samples (e.g. infrared dark clouds), PCCs are more quiescent, suggesting that most of them may be in the earliest phase of star formation. However, some PCCs are associated with protostars and molecular outflows, indicating that not all PCCs are in a prestellar phase. We have identified hundreds of starless dense clumps from a mapping survey with the Purple Mountain Observatory (PMO) 13.7-m telescope. Follow-up observations suggest that these dense clumps are ideal targets to search for prestellar objects.

• Journal of the Korean Society of Food Culture
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• v.30 no.2
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• pp.241-248
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• 2015

The purpose of this study was to investigate the perception of health functional foods and preference for desired onion peel products. Questionnaires were distributed to 582 adults (34.2% male, 65.8% female) living in Gyeongnam province. The major information sources on biological effects of onions cited by respondents were TV/radio (37.1%), followed by nearby people (32.8%) and Internet (11.0%), in that order. Reducing cholesterol effect was the most important factor in terms of perception and concerns relating to biological function of onions. Over 73% of subjects had experience of eating processed onion products, and among all types of onion products, onion juice (53.5%) was the most frequently eaten. The most considered factors for processing onion peel-derived functional foods were taste & odor (29.6%), convenience of eating (28.9%), and nutrition value (27.1%), in that order.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.4
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• pp.499-510
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• 2007

This study examined the intake patterns and information-seeking behaviors of elderly individuals with regard to health foods, according to sociodemograhic characteristics, awareness of health, and concerns and awareness about health foods. The data were collected from 421 elderly living in Seoul, Busan, Daegue, Daejon, and Gwangju, between January 17th and February 23rd, 2006. Frequencies and chi-square tests were conducted using SPSS Windows. The results are as follows: The respondents were highly concerned about their own health as well as health foods, and individuals primarily took nutritional supplements and glucosamine containing products. In addition, they had taken various health-improving foods. Most had intentionally consumed at least one health food, in order to maintain a condition of health. According to chi-square tests, women were more likely to consume health foods than men. The most important sources of information regarding health foods were family, relatives, and friends. Some respondents answered they had difficulties in obtaining and understanding health food-related information. Many respondents desired to get health food information regarding efficacy from TV, radio, and newspapers, as well as doctors, pharmacists, and dieticians.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.357-360
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• 2011

N-doped ZnO nanofilms were prepared by plasma enhanced atomic layer deposition method. $Zn(C_{2}H_{5})_{2}$, $O_{2}$ and $N_{2}$ were used as Zn, O and N sources, respectively, for N-doped ZnO films under variation of radio frequency (rf) power from 50-300W. Structural, optical and electrical properties of as-grown ZnO films were investigated with Xray diffraction(XRD), photoluminescence(PL) and Hall-effect measurements, respectively. Nitrogen content and p-type conductivity in ZnO nanofilms increased with the rf power.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.33-41
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• 2005

We have conducted observations toward the molecular cloud associated with the H II region Sh 156 in $^{13}CO$(J = 1-0), $C^{18}O$(J = 1-0), and CS(J = 2 -1) using the TRAO 14 m telescope. Combining with existing $^{12}CO$(J = 1- 0) data of the Outer Galaxy Survey, we delineated the physical properties of the cloud. We found that there is a significant sign of interaction between the H II region and the molecular gas. We estimated the masses of the molecular cloud, using three different techniques; the most plausible mass is estimated to be $1.37 {\times} 10^5 M_{\bigodot}$, using a conversion factor of $X = 1.9 {\times} 10^{20}\;cm^{-2} (K\;km\;s^{-1})^{-1}$, and this is similar to virial mass estimate. This implies that the cloud is gravitationally bound and in virial equilibrium even though it is closely associated with the H II region. In addition to existing outflow, we found several MSX and IRAS point sources associated with dense core regions. Thus, more star forming activities other than the existing H II region are also going on in this region.

• Journal of the East Asian Society of Dietary Life
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• v.8 no.2
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• pp.147-155
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• 1998

This study was carried out to investigate 192 female college students in Seoul area in order to know their dietary behavior regarding weight control, awareness of body image and weight, methods of weight control, meal volume, eating rate, frequency of eating, health score and nutritional knowledge score. Obesity was determined using body mass indes(BMI=Wt/Ht$^2$). The finding revealed that the average BMI was 19.7$\pm$ 1.94 Subjects were divided into 3 groups according to body image : lean group, moderate group and obese group, respectively. The results of this study are summarized as follows : 1) 48.9% of subjects thought they were obese, however their BMI was 20.9 2) 56.1% of subjects anted to attend a weight control program and the sources of information concerning weight control were newspapers and magazines, TV and radio in that order. 3) There were no significant difference among groups in the meal volume, frequency of eating and health score. 4) There were significant differences among groups in the eating rate and nutritional knowledge score. These results suggest that an accurate self perception of their bodies, and nutritional education are important for female college students.

• Nuclear Engineering and Technology
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• v.37 no.5
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• pp.447-456
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• 2005

Laser driven accelerators promise to provide an alternative to conventional accelerator technology. They rely on the excitation of large amplitude density waves in a plasma by the photon pressure of an intense laser. The density oscillations in which electrons and ions are separated, result in extremely large longitudinal electric fields that can be several orders of magnitude larger than those that are used in today's radio-frequency accelerators. Whereas this principle had been demonstrated experimentally for nearly two decades, it was not until 2004 that the production of high quality electron beams around 100 MeV was demonstrated. Analysis, aided by particle-in-cell simulations, as well as experiments with various plasma lengths and densities, indicate that tailoring the length of the accelerator, together with loading of the accelerating structure with beam, are the keys to production of mono-energetic electron beams. Increasing the energy towards a GeV and beyond will require reducing the plasma density and design criteria are discussed for an optimized accelerator module. The current progress and future directions are summarized through comparison with conventional accelerators, highlighting the unique short and long term prospects for intense radiation sources and high energy accelerators based on laser-drivenplasma accelerators.