• Geomechanics and Engineering
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• v.32 no.1
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• pp.21-34
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• 2023

In order to analyze the effect of the cyclic lateral loading on the response of a pile-soil system, a full-scale single steel pile was subjected to one-way cyclic loading. The test pile was driven into a bi-layered soil consisting of a normally consolidated saturated clay overlying a silty sandy layer, the site being submerged by water up to one meter above the mudline in order to reproduce the conditions of an offshore pile foundation. The aim of this paper is to present the main results of interpretation of the cyclic lateral tests in terms of pile deflections, bending moment, and cyclic P-Y curves. From these latter an absolute secant reaction modulus E_AS,N was derived and a simple calculation model of the test single pile is proposed based on this modulus. Two applications of the proposed model are carried out, one with a 2D finite element modelling, and the second with a load transfer curves-based method.

• Education of Primary School Mathematics
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• v.2 no.1
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• pp.53-64
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• 1998

Two different CAI programs have been developed to study the affect of CAI element for the types of learners'performance; (i) one is the 'CAI program 1' including the open questions for the fourth grade (the fourth period of the 'Time and Angle' in chapter 3 of the first term) of the mathematics class in the elementary school, and (il) the other is 'CAI program 2' for the existing methods. The fourth grade of Andong Songhyun elementary school has been chosen as the study subjects (243 learners), and the t-test and learners'interview have also been used to analysis the results of CAI programs. The CAI programs have only been used as the control variable. The developed CAI programs have been applied two different learners'groups to investigate the degree of performance among the superior, average, and inferior learners. For the superior group (p＜.0023) at the t＜3.2268 level and for the average group (p＜.0706) at the t＜1.8211 level the learner' group using CAI program 1 shows the higher performance compared with the learners' group using the CAI program 2, whereas fur the inferior group (p＜.8073) at the t＜.2458 level two programs did not show any difference. The learners interviews show that the superior and average groups have an interest for the open problems, whereas the inferior group do not shows an interest for the open problems. Thus, the CAI programs including the open questions (open fields, open evaluation) will be helped to the learners' group with the individual differences. Furthermore, it is expected that the CAI programs including the open questions as the mathematics and the program model of CAI can be used to develope the CAI program in future.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.20 no.4
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• pp.295-308
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• 2016

We propose a projection-based analysis of a new hybridizable discontinuous Gale-rkin method for second order elliptic equations. The method is more advantageous than the standard HDG method in a sense that the new method has higher-order accuracy and lower computational cost, and is more flexible. Notable distinctions of our new method, when compared to the standard HDG emthod, are that our method uses $L^2$-projection and suitable stabilization parameter depending on a mesh size for superconvergence. We show that the error for the solution of the equation converges with order p + 2 when we only use polynomials of degree p + 1 as a finite element space without postprocessing. After establishing the theory, we carry out numerical tests to demonstrate and ensure that the proposed method is effective and accurate in practice.

• Environmental Analysis Health and Toxicology
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• v.17 no.1
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• pp.63-71
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• 2002

The thermal desorption-gas chromatographic (TD-GC) system has been constructed for the measurement of volatile organic compounds. The thermal desortion unit is composed of four major parts: 1) the control part; 2) the thermal desorption part; 3) the focusing part; and 4) the injection part. The peltier element was introduced to the focusing part for the temperature of the focusing tube to reach-35$^{\circ}C$. The system was tested for the linearity of the calibration curves and reproducibility of instrumental analyses using some disinfection by-products (DBPs) and BTXs (benzene, toluene and p-xylene). The coefficients of determination (r$^2$) for all the calibration curves made were higher than 0.998, and the coefficients of variation (CV) for triplicate measurements were all within 10％. The system also has been tested for field applicability. The analysis of field samples showed that there was no breakthrough problem in the sampling system and that the system could be applied to field measurements.

• Journal of the Korean Chemical Society
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• v.33 no.3
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• pp.304-308
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• 1989

The spectrophotometric determination of $Lu^{3+},\;Eu^{3+}$ and some other rare earths have been investigated using Methyl Thymol Blue(MTB) as spectrophotometric reagent. Rare earth elements form a stable complex with MTB abount pH 6.5 and the ratio of its complex is 1 to 1. MTB has a absorption maxima at 440nm and rare earth MTB complex has absorption maxima 610nm at pH 6.5, respectively. The absorbance of the rare earth MTB complex is stable in 7 hours after color developing and obey the Beer law in the range of $0{\sim}110{\mu}g/50ml$. The ligand such as phosphate, citrate and EDTA decrease the absorbance of its complex considerably, and this method has a poor selectivity of each rare earth element and the molar absorptivity is $1.2{\sim}2.0{\times}10^4mol^{-1}{\cdot}l{\cdot}cm^{-1}$. In methyl alcohol, ethyl alcohol and acetone medium we did not find out any absorption change of the rare earth MTB complex.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.7
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• pp.1047-1053
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• 2006

The current study was designed to determine the effects of dietary docosahexaenoic acid (DHA) on fatty acid deposition in egg yolk and various tissues of laying Tsaiya ducks, and on the mRNA concentrations of hepatic lipogenesis-related transcription factors. Thirty laying ducks were randomly assigned to three treatments with diets based on corn-soybean meal (ME: 2803 kcal/kg; CP: 17.1%; Ca: 3.4%) supplemented with 0% (control diet), 0.5% or 2% algal DHA oil. The DHA content in egg yolks of the ducks was elevated significantly (p<0.01) with the supplementation of dietary DHA. The DHA percentage of the total fatty acids in the egg yolk of laying ducks was 0.5%, 1.3% and 3.4% for 0%, 0.5% and 2% algal DHA oil treatments, respectively, for the $1^{st}$ week, and 0.5%, 1.5% and 3.3% for the $2^{nd}$ week. Therefore, algal DHA oil can be utilized by laying Tsaiya ducks to enhance the egg-yolk DHA content. The concentrations of triacylglycerol (TG) and cholesterol in plasma of laying Tsaiya ducks were not affected by dietary DHA treatments (p>0.05). The DHA concentration in plasma, liver, and skeletal muscle was increased with the addition of dietary algal DHA oil (p<0.05). The mRNA abundance of sterol regulatory element binding protein 1 (SREBP1) and SREBP2 in the livers of laying Tsaiya ducks was not affected by dietary DHA, suggesting that the expression of these transcription factors is tightly controlled and not sensitive to DHA treatments.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.2
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• pp.182-188
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• 1986

A method of wideband constant phase control is proposed. This can be applied to reflection type phase shifter with p-i-n diode. Using the proposed method, a microwave phase network which consists of a transmission line and reactive circuit element is suggested. By determining theproper values of design parameters, the desired wideband constant phase with different specification can easily be designed. Also, using the proposed method, the parameters variation, and 1.1 dB of insertion loss in the range of 12% bandwidth.

• Journal of applied mathematics & informatics
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• v.9 no.1
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• pp.311-320
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• 2002

For second order linear elliptic problems over smooth domains, it is well known that the rate of convergence of the error in the $L_2$norm is one order higher than that in the $H^1$norm. For polygonal domains with reentrant corners, it has been shown in [15] that this extra order cannot be fully recovered when the h-version is used. We present theoretical and computational examples showing the sharpness of our results.

• KSBB Journal
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• v.28 no.2
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• pp.137-145
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• 2013

In order to develop new skin whitening agents, we prepared the $CH_2Cl_2$ layer (NGC) and BuOH layer (NGB) of 75% EtOH extract of the Nelumbinis nucifera Gaertner. We measured their tyrosinase inhibitory activity in vitro and melanin synthesis inhibitory activity in B16-F1 melanoma cells. They did not show inhibitory activity against mushroom tyrosinase but showed melanin synthesis inhibitory activity in a dose-dependent manner. In a melanin synthesis inhibition assay, NGC and NGB suppressed melanin production up to 52% and 46% at a concentration of $100{\mu}g/mL$, respectively. To elucidate the mechanism of the inhibitory effects of NGC and NGB on melanogenesis, we measured the expression of melanogenesis-related proteins by western blot assay. As a result, NGC suppressed the expression of tyrosinase, tyrosinase related protein 1 (TRP-1), tyrosinase related protein 2 (TRP-2), phosphorylated cAMP responsive element binding (p-CREB) protein, and microphthalmia associated transcription factor (MITF). And NGB inhibited the protein expression of tyrosinase and MITF, but had no significant effect on TRP-1, TRP-2, and p-CREB expression. Moreover, NGB increased the expression of phosphorylated extracellular signal-regulated kinase (p-ERK). In addition, we examined the inhibitory effect on the glycosylation of tyrosinase. As a result, NGC and NGB inhibited the activity of ${\alpha}$-glucosidase in vitro and the glycosylation of tyrosinase in B16-F1 melanoma cells. From these results, we concluded that NGC and NGB could be used as active ingredients for skin whitening.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.4
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• pp.625-642
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• 1993

Whether stress-absorbing elements are functional in an implant system has been an issue of interest in oral implantology. The unique feature of the IMZ implant system is the planned imitation of the stress-distributing function of the structural unit of the tooth, periodontium, and alveolar bone through the use of an intramobile element(IME). The purpose of this study was to compare the difference in the displacement and the stress distibutions of IMZ implant with a polyoxymethylene(POM) or a titanium IME under static load. Two dimensional finite element analysis(FEA) was applied for this study and two finite element models were created. PATRAN program(DPA Co.,USA), a software for FEA, and SUN-SPARC2GX(SUN Co., USA), a workstation computer, were used. $1Kg/mm^2$ of static load was loaded individually on each three point of crown of implant prosthesis ; central fossa(load 1), mesial cusp tip(load 2), distal cusp tip(load 3), The displacements of X- and Y-axis and total displacement were measured at mesial and distal cusp tips, mesial and distal points between crown and IME, and implant apex. The von Mises stress was measured at mesial and distal points between crown and IME, mesial and distal points between IME and TIE, mesial and distal alveolar crest, the mesial and distal midpoints of implant, and implant apex. The difference in resultant values were compared and evaluated statistically using paired t-test. The results were as follows : 1. Under the load 1, all the displacement of implant with titanium IME at 5 measuring points was larger than that of with POM IME except total and Y-axis displacement at implant apex. And the differences in stress distributions with POM and titanium were varied. 2. Under the load 2, all the displacement of implant with titanium IME at 5 measuring points was larger than that of with POM IME except X-axis displacement at distal cusp tip. And the differences in stress distributions were varied. 3. Under the load 3, all the displacement of implant with titanium IME at 5 measuring points was larger than that of with POM IME except Y-axis displacement at mesial cusp tip. And the differences in stress distributions were varied. 4. For the displacement, there was significant difference statistically only in total displacement (P<0.1), but was no significant difference in X- and Y-axis displacement(P>0.1). For the stress, there was no significant difference among the compared values.