• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.1
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• pp.71-81
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• 1989

Soil erosion was investigated to find out difference in amount of soil eroded from slope land at early stage of young grasses and at later stage with sufficient cover with different slopes. The six experimental plots were formed on 8$^{\circ}$, 10$^{\circ}$, 15$^{\circ}$, 20$^{\circ}$, and 25$^{\circ}$, with 2m width and 20m length located at the Hwak Kok Ri, Chun Sung Gun, Kang Weon Do. The amount of soil eroded and run-off were collected from 1. May 1987. to 30. October 1988, growing with grasses sowed 2. September 1987. The results were as follows : 1. The amount of soil eroded from the plots except 8$^{\circ}$ plot exceeded the allowable soil erosion with 14 ton/ha during the land formuing before establishment of sufficient surface cover with grasses. Therefore, proper soil conservation practice should be recommeneed. 2. The amount of soil eroded increased exponentially with increased slope as 1.24 times for 15$^{\circ}$1.65 times for 20*, and 2.94 times for 25$^{\circ}$, m comparing with standared 10$^{\circ}$ polt. 3. The erosion occurred mainly by high density of rainfall exceeding lOOmm as consecutive precipitation during the raining peried or accompanied by typhoon passing. 4. The significant soil erosion, when the land covering ratio was over 95% after seeding of grass, was recorded only by the single continuous storms over lOOmm of concentrated precpitation, of which amounts were 1/73~/250 of the allowable soil erosion. 5. The amount of soil erosion from the plots with sufficient surface cover with grasses increased as the slope increased however the amounts were small enough to be neglected. 6. Desolation by soil erosion would be minor problem up to the slope of 20$^{\circ}$ when the mountainous area developed to the grassland with sufficient cover. But it could be concerned on the turn to the hare land by the treading of livestocks with the land slope over 25$^{\circ}$. 7. The run-off of rainfall increased by the increament of slope but it was not exponentially increased. 8. The run-off of rainfall after seeding of grass reduced by 20% in comparison with the run-off of rainfall before seeding, which might be due to infiltration of rainfall promoted by the grass roots.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.4
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• pp.316-329
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• 2012

In this paper, optimum design process of ICP (Inductively Coupled Plasma) torch, which has been used widely in aerospace application, such as supersonic plasma wind tunnel, is presented. For this purpose, the behaviors of equivalent circuit parameters (equivalent resistance and inductance, coupling efficiency) were investigated according to the variations of torch design parameters (frequency, $f$, confinement tube radius, $R$ and coil turn numbers, $N$) in the basis of analytical and numerical MHD (Magneto Hydro-Dynamics) models combined with electrical circuit theory. From the results, it is found that equivalent resistance is increased with the increase of $f$ values but vice versa for equivalent inductance. For elevated values of $R$ and $N$, however, both parameters tend to increase. Based on these observations, ICP torch with a power level of 10 kW can be optimized at the design ranges of $f$=4~6 MHz, $R$=17~25 mm and $N$=3~4 to maximize the electrical coupling efficiency, which is the ratio of equivalent resistance to equivalent inductance.

• Explosives and Blasting
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• v.17 no.4
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• pp.67-88
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• 1999

Ground settlements induced by tunnel excavation cause the foundations of the neighboring superstructures to deform. An expert system called NESASS was developed to analyze the structural safety of such superstructures. NESASS predicts the trend of ground settlements to be resulted from tunnel excavation and carries out a safety analysis for superstructures on the basis of the predicted ground settlements. Using neural network techniques, NESASS learns a data base consisting of the measured ground settlements collected from numerous actual fields and infers a settlement trend at the field of interest. NESASS calculates the magnitudes of angular distortion, deflection ratio, and differential settlement of the structure and, in turn, determines the safety of the structure. In addition, NESASS predicts the patterns of cracks to be formed on the structure using Dulacskas model for crack evaluation. In this study, the ground settlements measured from the Seoul subway construction sites were collected and sorted with respect to the major factors influencing ground settlement. Subsequently, a database of ground settlement due to tunnel excavation was built. A parametric study was performed to verify the reliability of the proposed neural network structure. A comparison of the ground settlement trends predicted by NESASS with the measured ones indicates that NESASS leads to reasonable predictions. An examples is presented in this paper where NESASS is used to evaluate the safety of a structure subject to deformation due to tunnel excavation near to the structure.

• Conservation Science in Museum
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• v.6
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• pp.55-66
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• 2005

Three types of epoxy resins (Epo-Tek 301, Araldite 103, and Araldite 106) and three types of pigments (bunche, pastel, and conté), which are materials for porcelain restoration, were selected as examination materials. The tone change, porosity, and sedimental resulting from the mixtures of varying ratios of these three materials were observed. Samples were also made from the mixture of Epo-teck 301, four kinds of white pigments, and six types of fillers and subjected to ultraviolet ray penetration for 200 hours to observe the oxidation of the epoxy resins. The result showed that the chemical composition of pastel drastically changed when mixed with Epo-tek 301. Although bunche and conté displayed clear colors, those of conté were less clear when it was mixed with other substances. Adding a small amount of Epo-tek 301 tended to be driven into the corner, whereas mixing a large amount caused saturation and boiling. On the other hand, AW 106 did not display clear colors owing to its high viscosity; when mixed in large amounts, however, the clarity of colors improved. For AY 103, a similar standard of color clarity was maintained regardless of the mixture ratio. The following was ranked according to the level of porosity: [Pastel>bunche≒conté]. In terms of sedimentary, however, [bunche>conté>Pastel], [Epo-tek 301> AY 103> AW 106]. The result of measuring the degree of yellowing revealed that titanium, pastel, silicon dioxide, and kaolin tended to turn yellow, whereas bunche, conté, diatomaceous earth, and calcium hydroxide tended to resist yellowing.

• Journal of the Korean Wood Science and Technology
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• v.27 no.3
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• pp.73-81
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• 1999

This paper was intended to evaluate the effect of the blending condition of pigments on the packing structure of coating color and the interaction between pigments and latices on the optical and interior properties of coated paper. It has been studied many ways to modify the coating structure to induce the interaction among coating components as followings ; 1) to use dispersant for pigment, 2) to control the charge density and the type of surface charge of latex, 3) to support the water retention by adding water retention agent or flow modifier. This paper was performed through the introduction of interaction between pigments which were two kinds of clays and one precipitated calcium carbonate(PCC) and ionic latices of which anionic and amphoteric respectively under the certain blending condition of pigments where their blending ratio of clays to calcium carbonate was 70pph to 30pph. The reason is that packing volume of pigments was highest in that region and thixotropical behavior appears in measuring rheology of coating color. We measured the properties of coating color, interaction with pigments and latex, and properties of coated paper and its printability. As a results, we could find out that amphoteric latex had a great influence on the interaction with pigments, especially clays, no matter what grade and also affected the coating structure significantly in case that this blending condition was 70(clays) to 30(PCC). It produced a powerful effect on the forming of bulky and smooth coating structure and in turn improved the printability of coated paper.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.1
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• pp.25-33
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• 2016

The study was performed to investigate the effects of whey protein-rich meal substitute added with vitamins, minerals, and lactobacillus powder probiotics on weight loss, body fat, and body composition in 24 female volunteers for 4 weeks. Whey protein-rich meal substitute was consumed with low-fat, high calcium milk (1% fat, 260 mg/200 mL) twice a day. Subjects submitted 3-day diet records and a life-style questionnaire before the study. During the study, subjects were required to turn in a diet record every day and consume the meal substitute formula in the metabolic ward at C university for 4 weeks. Anthropometric measurements were carried out weekly by Inbody 7.0. The dietary intake and anthropometric data were analyzed to compare changes before and after the study by paired t-test with SPSS version 23.0. The subjects were mostly early 20's and either overweight or obese and highly motivated to lose weight. Most of the subjects consumed three meals per day regularly and spent mostly 10~15 minutes for a meal. Their caloric intake was relatively low and decreased from 1,360 kcal at week 0 to 1,100 kcal after 4 weeks. However, total protein intake increased while carbohydrate and fat intakes decreased (p<0.05) after the trial. Nine vitamin intakes after the study improved compared to those before the study (p<0.05). After the study, subjects showed lower body weight (-1.8 kg), body fat (-0.94 kg), percent body fat (-0.86%), as well as waist circumference (-4.52 cm), hip circumference (-0.44 cm), waist hip ratio (-0.05), and triceps skinfold thickness (-2.39 mm) compared to those at week 0 (p<0.05). Muscle mass tended to be less compared to week 0, although there was no significant differences between weeks 0 and 4. In conclusion, diet trial with whey protein-rich meal substitute induced weight loss and positively changed body fat parameters and body composition.

• Management & Information Systems Review
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• v.33 no.4
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• pp.21-38
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• 2014

This study investigates whether and how a firm's cost of equity is influenced by the extent of a firms's name change. Even though corporate name change doesn't give any benefit to investors, it can be a signaling about firm's future valuation. And also, if that signaling has high credibility, it can be decrease information cost and the firm's cost of equity. on the contrary to this, if corporate name change is kind of break with the past and corporate image laundering, it is bad signaling to investors. So it can be increase information risk and the firm's cost of equity. Using yearly cross-sectional regressions of the cost of equity on our proxies for corporate name change, size, beta, market-to-book ratio and other innate risk factor over the 2005-2010, we find that the cost of capital is positively associated with corporate name change after controlling for all other factors. This result implies that corporate name change increase information risk of the business, and thus increase information asymmetries between managers and outside investors with respect to a firm's true future value. This increases information risk, and creates an adverse selection problem, on the part of outside investors. Rational investors therefore demand a premium for bearing this corporate name change-related information risk, which in turn leads us to observe a positive relation between the intensity of corporate name change and the cost of equity.

• Journal of the Korean Magnetics Society
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• v.17 no.4
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• pp.162-165
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• 2007

We investigated the effects of the capping layer materials on the crystallization of the amorphous top-CoFeB (t-CoFeB) electrode and the magnetoresistance properties of the magnetic tunnel junctions (MTJs). When the hcp(002)-textured Ru capping layer was used, the amorphous t-CoFeB was crystallized to bcc-CoFe(110). The CoFe(110)/Ru(002) texture relation can be minimized the lattice mismatch down to 5.6%. However, when the fine polycrystalline but almost amorphous TiAl or amorphous ZrAl were used, the amorphous t-CoFeB was crystallized to bcc-CoFe(002). When the amorphous capping materials were used, the evolution of the t-CoFeB texture was affected mainly by the MgO(001) texture. Consequently, the M ratios of the annealed MTJ capped with the ZrAl and TiAl (72.7 and 71.8%) are relatively higher than that of the MTJ with Ru capping layer (46.7%). In conclusions, the texture evolution of the amorphous t-CoFeB during the post deposition annealing could be controlled by the crystallinity of the adjacent capping layer and in turn, it affects the TMR ratio of MTJs.

• Korea journal of population studies
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• v.28 no.2
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• pp.219-243
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• 2005

This paper reviews research outputs in Korea Journal of Population Studies (KJPS) and the changes in their contents during the period of 1977-2004. In the early years of KJPS, various types of outputs were published, but changes have been made into a direction that research articles compose the main context of the journal. As the journal published twice a year, the total number of articles of the journal shows a trend of marked rise. An analysis of the themes of articles shows that the trend of research in Korean demography has changed hand in hand with transformations of the Korean society. The traditional topics such as population policy, fertility, mortality, and migration were popular before. Labor force, nuptiality, family, aging, regional studies are found to be more popular themes of research recently. Reflecting academic and social demands, KJPS has a broaden range of authors, such as professor, researcher, a government employee, post-doc, and graduate students. The articles written by those working in universities have increased continuously, while research outputs of research institutes have decreased recently. The data for analysis used in articles are varied from but concentrated in some materials - census, vital statistics and various survey data. In early years of KJPS, relatively simple techniques of analysis were adopted in the majority of articles. However, more sophisticated techniques including applied regression analysis, logistic analysis and analysis of survival ratio turn out to be more popular recently. Finally, several suggestions for the future research are presented in this paper.

• Journal of the Korean Geotechnical Society
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• v.28 no.9
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• pp.5-15
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• 2012

Field monitoring data for embankments in thirteen road construction sites at coastal area of the Korean Peninsula were analyzed to investigate the characteristics of lateral flow in soft grounds, to which vertical drain methods were applied. First of all, the effect of the embankment scale on the lateral flow was investigated. Thicker soft soils and lager relative embankment scale produced more horizontal displacements in soft grounds. Especially, if thick soft grounds were placed, the relative embankment scale, which was given by the ratio of thickness of soft ground to the bottom width of embankments, became larger and in turn large horizontal displacement was produced. And also higher filling velocity of embankments induced more horizontal displacements in soft grounds. The other major factors affecting the lateral flow in soft ground were the thickness and undrained shear strength of soft grounds, the soil modulus and the stability number. Maximum horizontal displacement was induced by less undrained shear strength and soil modulus of soft grounds. Also more stability numbers produced more maximum horizontal displacements. When the shear deformation does not develop, the stability number was less than 3.0 and the safety factor of bearing was more than 1.7. However, if the stability number was more than 5.14 and the safety factor of bearing was less than 1.0, the unstable shear failure developed in soft ground. 50mm can be recommended as a criterion of the allowable maximum horizontal displacement to prevent the shear deformation in soft ground, while 100mm can be recommended as a criterion of the allowable maximum horizontal displacement to prevent the shear failure in soft ground.