• Journal of the Korean Magnetics Society
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• v.3 no.2
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• pp.94-100
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• 1993

Electronic and magnetic properties of the novel rare-earth permanent magnet, $Sm_{2}Fe_{17}N_{3}$, are investigated by performing self-consistent local density functional electronic structure calculations. Employing the LMTO(Linearized Muffin-Tin Orbital) band method, we have obtained the electronic band structures for both paramag-netic and ferromagnetic phases of $Sm_{2}Fe_{17}N_{3}$. Based on the energy band structures, we have studied bonding ef-fects among Sm, Fe, and N atom as well as electronic and magnetic structures. It is found that the N atom sub-stantially reduces the magnetic moment of neighboring Fe atoms through the hybridization interaction and also plays a role in stabilizing the structure. the average magnetic moment of Fe atoms in the ferromagnetic phase of $Sm_{2}Fe_{17}N_{3}$ is estimated to be $2.33{\mu}_B$, which is ~8% larger than the magnetic moment of $Sm_{2}Fe_{17}$, $2.16{\mu}_B$. The Fe I (c) atom, which is located farthest from the N atom and surrounded by 12 Fe nearest neighbors, has the largest magnetic moment ($2.65{\mu}_B$), while the Fe III (f), whose hybridization interaction with N atom is very strong, has the smallest magnetic moment($1.96{\mu}_B$).

• Korean Journal of Plant Resources
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• v.10 no.2
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• pp.140-144
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• 1997

This experiment was carried out to investigate the proper planting method of Rehmannia glutinasa Liboschitz. A Chungbuk local cultivar was sown on the seed bed of 200cm with the planting density of 30cm(6 rows) $\times$ 8.5cm(30 rhizome per $\textrm{m}^2$). The experimental design was randomized block design with 3 replications. And the result was summarized as follows. The emergence date of level Planting(control : 0$^{\circ}$) was May 23, but the emergence dates of Oblique planting(45$^{\circ}$) and Upright planting(90$^{\circ}$) treatments were later than the control by 2~4 days. And the leaf length and the ratio of leaf length/leaf width were not significantly different. As compared with the 29.2cm and 10.0mm of the rhizome length and the rhizome diameter of level planting treatment, the rhizome length of Oblique planting treatment was decreased by 3.4cm and 0 mm. The length and diameter of rhizome of the Upright planting treatment was decreased by 2.8cm and 1.0mm. And the order of sugar content was level Planting > Oblique planting > Upright planting. The total yields were decreased by 9% in the Oblique planting and by 15% in the Upright planting compared to 1,203kg/10a in the control, and the commercial yields showed the same tendency. The level planting treatment was found to be most proper for sowing of Rehmannia glutinasa Liboschitz in the middle inland region of Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.3
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• pp.263-268
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• 1981

Fourteen hundred and one landraces of sesame cultivated in Korea were collected and evaluated for their major agronomic characters and yield potential under conditions of May 15 sowing, 50\timesl5cm planting density and 4-3-2 kg/l0a of N-P_2 $O_{5}$-K_2 O application in Suweon in 1977. Seventy nine percent of the collection had white seed coat color, and 29% was brown. One capsule type with two rooms-four cells was 75%, one capsule type with four rooms-eight cells was 20%, and three capsule type with two rooms-four cel1s were 5% of the varieties collected, But, two one-capsule type varieties with three rooms-six cells were also found. Days to flowering from emergence were long in the varieties collected in the central northern area, but short in the varieties collected in the southern area. Number of capsule per plant was more in the central northern varieties than in the southern varieties. Number of branch per plant was more in the one capsule type varieties with two rooms-four cells than in the three capsule type varieties with two rooms-four cells and in the one capsule type varieties with four rooms-eight cells. There were significant corelations between number of capsules per plant and grain yields in the one capsule type varieties with four cells. Grain yields had significant correlation with number of capsules per plant and number of branches per plant.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.2
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• pp.161-172
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• 1997

In this paper, electromagnetic scattering by a perfectly conducting strip grating on dielectric multilayers is analyzed for the normalized reflected and transmitted power by applying the Fourier-Galeakin moment method. The induced current density is expanded in a series of multiplication of chebyshev polynomials of the first kind and functions with appropriate edge boundary condition, the continuous condition of electromagnetic field is applied in the boundary planes. The confirm the validity of the proposed method, the nor- malized reflected and transmitted power obtained by varying the relative permittivity and thickness of each dielectric layers are evaluated and compared with those of the existing numerical method and a paper, and then the numerical results in this paper are in good agreement with those of the existing numerical method and the paper. The sharp variation position in the geometrically normalized reflected and transmitted power can be moved by the incident angle, grating period, and the relative permittivity and thickness of the dielectric multilayers, these sharp variation points which are called the Wood's anomaly of the Geome- trically normalized reflected power are observed as a main factor when the reflected powers of the higher order mode are transitted between propagating and evanescent modes, and the local minimum positions are slightly moved to the left hand direction in which grating period is getting small according to the increase of the relative permittivity of dielectric layers.

• Journal of the Korean Geographical Society
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• v.49 no.6
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• pp.935-948
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• 2014

As chronic diseases have become more prevalent and problematic, effective cares for major chronic diseases have been a locus of the healthcare policy. In this regard, this study examines how region-specific characteristics affect the prevalence of hypertension in South Korea. To analyze, we combined a unique multi-year data set including key indicators of health conditions and health behaviors at the 237 small administrative districts. The data are collected from the Annual Community Health Survey between 2009 and 2011 by Korea Centers for Disease Control and Prevention and other government organizations. For the purpose of investigating regional variations, we estimated using Geographically Weighted Regression (GWR) and decision tree model. Our finding first suggests that using the multi-year data is more legitimate than using the single-year data for the geographical analysis of chronic diseases, because the significant annual differences are observed in most variables. We also find that the prevalence of hypertension is more likely to be positively associated with the prevalence of diabetes and obesity but to be negatively associated with population density. More importantly, noticeable geographical variations in these factors are observed according to the results from the GWR. In line with this result, additional findings from the decision tree model suggest that primary influential factors that affect the hypertension prevalence are indeed heterogeneous across regional groups. Taken as a whole, accounting for geographical variations of health conditions, health behaviors and other socioeconomic factors is very important when the regionally customized healthcare policy is implemented to mitigate the hypertension prevalence. In short, our study sheds light on possible ways to manage the chronic diseases for policy makers in the local government.

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.81-91
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• 2005

'Coarse grained material' refers to crushed stones or gravels, and the behaviour of soil containing coarse grained material is not easily defined using the conventional soil mechanics theory due to the influences of large particles, therefore large scale test is essential to investigate their effects. Previous studies have identified the major factors affecting the properties of coarse grained materials by using large scale shear testing apparatus, such as maximum particle size, water content, density and uniformity coefficients. In this paper, the effect of variation of maximum particle size and water content on shear strength was analyzed from the results of large scale shear test. In addition, the fiction coefficient at critical state per vertical load was estimated using the equation proposed by Wood (1998). The sample for the test was obtained from the local quarry sites. Tests results show that the shear strength for 50.8 m maximum particle size is relatively larger than that of 76.3 m and air-dry sample has larger shear strength than saturated sample. In the meantime, the friction coefficient at critical state shows $1.0\sim1.6$ according to the test conditions.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.6
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• pp.199-208
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• 2013

The purpose of this study is to compare the vegetation structure in complementary forests of villages between Korea and China. For this study, Jinan in Korea and Qingzhou in China were selected through a pre-survey about the representative regions of both countries. The main research method used was field study. A comparative analysis between the two regions was performed by a frequency analysis of the surveyed data. The data obtained in the study shows the vegetation structure in complementary forests of villages in the two regions have many differences which are related to the local culture. As a result, it was identified that the average number of species was the same at 2.9 and the average number of trees, total number of trees, and tree density in Qingzhou were considerably greater than those in Jinan. Also, it was identified that tree height, average breadth height diameter and crown width in Jinan were considerably greater than those in Qingzhou. Furthermore, it was identified that both the forest state and the principal species of tree are both very different according to the different cultures. Through this identification, it is considered that this study will be helpful in establishing policy direction in both countries about the restoration and management of complementary forests.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.269-275
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• 2017

Shipwreck remains below the seabed not only effect the ocean currents and tides, but influence the physical properties of sediments and sedimentary environments that comprise the seabed. In particular, the influence of local shipwrecks discovered buried in the seabed on the sediment is visible. In this study, sediments were collected from the surrounding area of Taean Mado No.3 shipwreck using grab samplers and vibro-corers. The physical properties of these sediments were analyzed to evaluate the impact of the Taean Mado shipwreck No.3 remains. Sediment core analysis by means of density and ultrasonic velocity showed that shear strength tended to increase with depth, whereas moisture content and porosity tended to decrease with depth. Grain size analysis results are shown in terms of Folk's classification, where the grain size of the core samples in the study area indicate mud or sandy mud, and that of the grab sample indicates a muddy sand. Results of the sedimentation rate analysis indicate a rate of 2.84 cm/year and carbon dating of the 150 cm deep seashell indicates the Neolithic age. These sediments were analyzed for the study of the relationship between the Taean Mado shipwreck No.3 remains and the physical properties of the sediment.

• Journal of the Korean institute of surface engineering
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• v.41 no.6
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• pp.292-300
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• 2008

Dental implant system is composed of abutment, abutment screw and implant fixture connected with screw. The problems of loosening/tightening and stability of abutment screw depend on surface characteristics, like a surface roughness, coating materials and friction resistance and so on. For this reason, surface treatment of abutment screw has been remained research problem in prosthodontics. The purpose of this study was to investigate the stability of TiN and WC coated dental abutment screw, abutment screw was used, respectively, for experiment. For improving the surface characteristics, TiN and WC film coating was carried out on the abutment screw using EB-PVD and sputtering, respectively. In order to observe the coating surface of abutment screw, surfaces of specimens were characterized, using field emission scanning electron microscope(FE-SEM) and energy dispersive x-ray spectroscopy(EDS). The stability of TiN and WC coated abutment screw was evaluated by potentiodynamic, and cyclic potentiodynamic polarization method in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. The corrosion potential of TiN coated specimen was higher than those of WC coated and non-coated abutment screw. Whereas, corrosion current density of TiN coated screws was lower than those of WC coated and non-coated abutment screw. The stability of screw decreased as following order; TiN coating, WC coating and non-coated screw. The pitting potentials of TiN and WC coated specimens were higher than that of non-coated abutment screw, but repassivation potential of WC coated specimen was lower than those of TiN coated and non-coated abutment screws due to breakdown of coated film. The degree of local ion dissolution on the surface increased in the order of TiN coated, non-coated and WC coated screws.

• Fire Science and Engineering
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• v.31 no.6
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• pp.47-52
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• 2017

The recent tragic outbreak of fire at the Grenfell Tower in the United Kingdom compels all branches of government to reexamine and reassess the safety measures against fires in high-rise buildings from a broad perspective. Accordingly, this study examined what problems stem from the current evacuation codes by comparative analysis of the high-rise apartment evacuation codes that range over various individual laws before introducing a new evacuation code. The outcome of this study can be utilized as basic data for amending the existing evacuation codes for high-rise buildings. The codes related to high-rise building evacuation include the Building Act, the Housing Act, the Skyscraper Disaster Management Act, and the Fire-Fighting System Act. Some local governments have also drawn up their own codes and put them into practice. Comparative analysis of the major evacuation codes has helped identify a variety of problems, such as different codes being applied to each individual law and ordinance, the use of additional codes other than the provisions of laws and ordinances, and the in effectiveness of evacuation codes. Most of these problems occur when diverse codes are applied to a single building, which means that cooperation among the relevant ministries is urgently needed to improve the related codes in the future.