• Journal of the Korean Geotechnical Society
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• v.29 no.3
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• pp.51-60
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• 2013

The slime, deposited in the bored pile due to falling soil particle, reduces the bearing capacity of bored pile and thus the stability of construction also decreases. The weight pendulum and iron have been used for estimating the slime thickness based on the subjective judgment and thus the previous method has a limitation of reliability. The objective of this paper is to suggest the method for estimating the slime thickness by using characteristics of electrical resistivity as scientific method. The temperature-compensation resistivity probe (TRP), which has a conical shape and the diameter of 35.7mm, is applied to the measurement of the electrical resistivity in the borehole during penetration. The field tests are carried out for estimating the slime thickness in the application site of bored pile. The slime thickness is calculated through the difference between excavation depth of borehole and measured data. Furthermore, the laboratory tests are also conducted for investigating effects of casing, time elapsing and relative density by using the specimen of slime. The laboratory test supporting the suggested method is reasonable for determining the slime depth. The paper suggests that the electrical resistivity method may be a useful method for detecting slime thickness and the method is expected to be applicable to various sites of bored piles.

• Journal of Sericultural and Entomological Science
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• v.51 no.2
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• pp.107-113
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• 2013

The black soldier fly larvae are able to decompose various organic wastes such as livestock manures and food wastes. We tested whether the quality of the insect derived compost, i.e. larval feces, was comparable to that of a commercial fertilizer. Chemical analysis of Hermetia. illucens compost was suitable as a fertilizer. When the kidney bean (Phaseolus vulgaris L.) was raised on the culture soil treated with the H. illucens compost, the growth of leaf area, total dry weight and leaf dry weight increased significantly. The H. illucens compost is thought to act as an increasing factor of RGR (relative growth rate) from the beginning of growth and also had a great effect on the relative growth rate throughout the late stage of growth. There is high statistical significance between NAR (net assimilation rate) and RGR (relative growth rate), but no significance between RGR and LAR (leaf assimilation rate) of the treatments. In addition, the treatment of H. illucens compost promoted the thickness of leaves from the beginning of growth and the tendency of thickening leaves from the beginning of growth and the effect continued throughout the late period of growth. When mixed with 50% of H. illucens compost rather than 25%, it showed the greater effect on the plant growth.

• Journal of Chest Surgery
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• v.43 no.5
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• pp.482-489
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• 2010

Background: The purpose of this study was to determine whether hand-measured carotid intima-media thickness (IMT) was a reliable and simple tool that could be used to evaluate the severity of stable coronary artery disease (CAD) with normal high-sensitivity C-reactive protein (CRP). Material and Method: We examined left carotid IMTs in 688 patients with stable CAD and excluded 121 patients with abnormally elevated hs-CRP ($\geq$0.5 mg/dL). We sought to determine the association between risk factors and the severity of stable CAD and carotid IMT in 567 patients who were divided into lower and higher groups based on the median value. Patients underwent a coronary artery angiogram and had at least significant stenosis (>50% of the original luminal diameter involving one or more major coronary artery). Result: Of the 567 patients, 300 (52.9%) were in the lower IMT group and 267 (47.1%) were in the higher IMT group; the median value was 0.76 mm. By multivariable logistic regression analysis, the following groups were different: older age (~49 vs. 70~ years, respectively; OR=6.552), high FBS (~99 vs. 120~ mg/dL; OR=1.713) and severity of CAD (1 vessel vs. 2 vessel disease; OR=1.711, 1 vessel vs. 3 vessel disease; OR=1.714). Conclusion: We conclude that there are correlations between increased carotid IMT and severity of CAD in stable angina patients with normal CRP levels.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.1
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• pp.16-20
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• 1988

Square slices of sea tangle was dried in hot air drier that could be controlled air temperature, relative humidity and air velocity. Under various drying conditions, drying and shrinking characteristics were investigated. 1) During drying sea, tangle, the constant rate period was nonexistant and the falling rate could be devided into a 2 periods, namely, a first falling rate period and a second falling rate period. 2) The tip part was proceeded more shrinkage than base part, and under drying condition of air temperature $50^{\circ}C$, relative humidity $30\%$, air velocity 0.4m/s, when the moisture content was reduced to $20\%$, the shrinking ratio of tip part, middle part and base part were 57.5, 54.0 and $42.7\%$, respectively. 3) The drying shrinking and drying rate increased with decreasing relative humidity, but when the moisture content was reduced to $20\%$, the shrinking ratio increased with increasing relative humidity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.5
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• pp.1051-1059
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• 2015

Wave runup is one of the most important factors affecting the design of coastal structure exposed to wave attack. In this study, two dimensional laboratory tests were conducted under the different random wave conditions and structure configurations to develop a formula to predict runup heights. Rubble-mound structure consisted of tetrapod armour blocks with 1:1.5 and 1:2 slopes. The relative water depths (the ratio of the significant wave height to water depth at the toe) ranged from 0.14 to 0.56. The formula proposed here is applicable to surf similarity parameter ranging from 2 to 6. Runup heights on 1:2 slope were higher than those on 1:1.5 slope. Runup heights were reduced by 5% when the armour layer thickness increased two times.

• Journal of Nutrition and Health
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• v.24 no.4
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• pp.308-313
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• 1991

This study attempted to measure subcutaneous fat thickness by the use of ultrasonic wave in age and sex matched Korean subjects, and to observe correlation between fat thick-ness and physical indices. In male, fat thickness of suprailiac area showed the highest value of $9.40{\sim}9.51mm$ and then subscapular was $6.60{\sim}6.84mm$, femoral was $6.48{\sim}7.04mm$ and triceps regions was $3.48{\sim}3.69mm$. In female, femoral subcutaneous fat thickness was the higher. $11.85{\sim}12.15mm$and then suprailiac was $8.79{\sim}9.87mm$ subscapular was $6.20{\sim}6.91mm$ and triceps fat thickness was $4.80{\sim}4.93mm$. In male, fat thickness of triceps and relative body weight(RBW). body mass index(BMI), triceps or $R\ddot{o}hrer$ index were positively correlated. Correlations between suprailiac and weight, relative body weight(RBW). body mass index(BMT), $R\ddot{o}hrer$ index or subscapular were positively significant. In female. there were positive correlations between fat thickness of femoral and RBW, BMI, or $R\ddot{o}hrer$ index. And there were no positive correlations in other parts of the body.

• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.29-44
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• 1999

This paper shows the results of model tests on the lateral behavior of single rigid pile, which was constructed by driving, in homogeneous and non-homogeneous (two layered) NakDong River sands. The purpose of the present paper is to investigate the effect of ratio of lower layer thickness to embedded pile length, relative density of sand and pile construction conditions (Driven & Embedded piles) on the characteristics of lateral behavior of single pile. These effects can be quantified only by the results of model tests. As a model result, the lateral behavior depends upon the pile construction condition in loose-density soil more than in high-density soil. If the pile construction depends upon driving construction, the decrease of deflection remarkably increases for both loose homogeneous sand and non-homogeneous soil$(E_{h1}/E_{h2}/=0.18)$ with high thickness of upper layer but the decrease of maximum bending moment shows the opposite result to the decrease of deflection. And, with respect to deflection, it was found that the deflection ratio $(y_{Driven}y_{Embedded})$ of embedded to driven piles has the ranges of 0.65 - 0.88 $(D_r=90%)$0.38 - 0.65 $(D_r=61.8%)$ for each relative density of homogeneous soil and the range of 0.6 - 0.88 for non-homogeneous soil. Also, in this study, the experimental equation for the effects of drop height (DH) and H/L on the ratios of $y_D/y_E\; and MBM_D/MBM_ E$ is suggested from model tests.

• Journal of Korean Society of Steel Construction
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• v.27 no.1
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• pp.31-42
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• 2015

The plastic stress distribution method and the strain compatibility method are the two representative methods to calculate the P-M interaction strength of RCFT (rectangular concrete filled tube) columns. The plastic stress distribution method is approximate while the stress compatibility method should approach the exact solution if accurate constitutive relations of the materials involved are used. Recent study by the authors pointed out that, because of lack of accurate constitutive model for the concrete confined by the rectangular steel tube, no strain compatibility method according to the current structural provisions provides a satisfactory prediction of the P-M interaction strength of RCFT columns under various material combinations. An empirical constitutive model which can capture the stress-strain characteristics of the confined concrete of RCFT columns is proposed based on analyzing extensive exisitng test database. The key idea was to define the concrete crushing strain as a function of steel-to-concrete strength ratio and width-to-thickness ratio of steel tube. It was shown that the proposed model leads to more accurate and more consistent prediction of the P-M interaction strength of RCFT columns under general design conditions.

• Journal of the Korean Magnetics Society
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• v.5 no.1
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• pp.42-47
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• 1995

FeN thin films for inductive recording heads were sputter deposited using RF diode sputtering mehtod from a pure iron target onto 7059 glass substrates, and their magnetic properties were measured. The magnetic properties were greatly affected by film thickness, gas pressure, sputter power and flow ratio of $N_{2}$ to Ar. Single layer FeN films with their thickness varied from $1,000\;{\AA}$ to $6,000\;{\AA}$ were doposited. 800 W sputter power, 3 mT gas pressure, $N_{2}$ to Ar flow ratio of 6.6 : 100 were the sputtering conditions. Up to 7 layers of FeN films having total thickness of $6,000\;{\AA}$ were deposited using $SiO_{2}$ of $30\;{\AA}$ thickness as intermediate layers and their coercivity and saturation magnetization were measured. The sputtering conditions were the same as those in the single layer films. Easy axis coercivity of the single layer FeN films gradually decreased as their thickness was increased, but for the films with their thicknesses above $3,000\;{\AA}$, the coercivity changed very little. As the number of the FeN layers were increased, the coercivity decreased We estimated the grain size of FeN films from the FWHM (Full Width at Half Maximum) of X-ray diffraction peaks. The grain size steadily decreased from about $200\;{\AA}$ to $120\;{\AA}$ as the number of layers were increased. Minimum hard axis coercivity of 0.4 Oe was obtained when the number of layers was four. Maximum relative permeability was 2,900 when the number of layers was three. The cut off frequeocy of the multilayer films were above 100 MHz.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.161.2-161.2
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• 2017

희토류계 영구자석은 대부분의 전기, 전자 제품의 핵심부품이며 높은 보자력, $BH_{max}$를 가지고 있어 자기기록저장매체, MEMS(엑츄에이터), 소형센서, 소형모터 등의 응용 분야에 적용시키기 위해 다양한 연구들이 진행되고 있다. 그러나 영구자석에 들어가는 희토류계 원소의 수급의 어려움 및 가격의 문제점으로 친환경 자석으로의 전환 및 희토류나 중희토류를 사용하지 않는 비희토류계 영구자석을 제조 및 개발하는데 많은 연구가 이루어지고 있다. 이 중 Fe-N 계 자성물질인 $Fe_{16}N_2$는 포화 자화 값이 현재까지의 비희토류계 자성물질 중 가장 높은 값(240emu/g)을 나타내며 상대적으로 높은 결정자기이방성 상수를 가지고 있어 비희토류계 영구자석 물질 중 하나로 주목받으며 연구되어지고 있다. 본 연구에서는 $Fe_{16}N_2$ 박막을 얻기 위해 DC Magnetron Sputtering 방법을 이용하여 Si wafer 위에 박막을 증착하고 증착시간에 따라 두께를 제어하여 제조한 후 박막의 미세구조, 상 분석, 자성 특성을 관찰을 통해 최적의 공정 조건을 찾고자 하였다. 증착 시간에 따른 박막의 성장 속도는 일정하게 증가하였으며, 증착 시간의 증가에 따라 박막 내 $Fe_{16}N_2$의 상대적인 분율은 감소하였다. 모든 공정 조건에서 $Fe_3N$, $Fe_4N$, $Fe_{16}N_2$ 상들이 섞여 성장하였으며 XRD를 통한 상분석과 더불어 VSM을 통한 자성 특성을 분석해본 결과 $Fe_{16}N_2$의 분율을 가장 높게 성장된 공정 조건은 증착 시간이 10분이며 박막의 두께가 ${\sim}1{\mu}m$ 일 때, 최적의 조건을 얻을 수 있었으며, 이 때의 자성 특성을 분석한 결과 ~2.45T의 포화 자화 값과 ~1.41T의 잔류 자화 값을 얻을 수 있었다.