• Proceedings of the KSME Conference
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• 2007.05a
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• pp.403-404
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• 2007

Compound eyes in nature present intriguing topics in physiological optics due to their unique optical scheme for imaging. For example, a bee's eye has thousands of integrated photonic units called ommatidia spherically arranged along a curvilinear surface so that each unit points in a different direction. The omni-directionally arranged ommatidium collects incident light with a narrow range of angular acceptance and independently contributes to the capability of wide field-of-view (FOV) detection. Artificial implementation of compound eyes has attracted a great deal of research interest because the wide FOV exhibits a huge potential for medical, industrial, and military applications. So far, imaging with a FOV over $90^{\circ}$ has been achieved only with fisheye lenses which rely on bulky and expensive multiple lenses and require stringent alignment. In this talk, we will discuss about the spherical 3D arrangement of the photonic structures of biologically inspired artificial compound eyes in a small form-factor to have and the functional and anatomical similiarity with natural compound eyes.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1521-1523
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• 2010

Bioassay-guided fractionation of a methanol extract of Ganoderma lucidum gave a pure cholesterol esterase inhibitor. On the basis of spectroscopic analysis and comparison with data from the literature, the structure of this compound was identified as $5{\alpha},8{\alpha}$-epidioxyergosta-6,22-dien-$3{\bet}$-ol (compound I). This compound inhibited cholesterol esterase activity with an $IC_{50}$ value of $42{\mu}M$. Lineweaver-Burk plot analysis revealed that compound I is a noncompetitive inhibitor. The findings of this study suggest that compound I may be the active principle of the hypocholesterolemic effect of Ganoderma lucidum.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1033-1034
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• 2006

Metallic compound of ternary Al-B-C system was prepared by mechanical alloying (MA) using Al, boron and graphite powders as starting materials. MA was carried out using Spex 8000 mixer/mill for 50 hours in an argon atmosphere without process control reagent such as methyl alcohol. The MA powders obtained were heat-treated in vacuum at the temperature of 873 and 1273 K for 5 hour. Pure ternary Al-B-C compound was obtained in the chemical content of Al:B:C=55:27:18. The ternary compound obtained in this study has a new phase whose crystal structure is not identified yet.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.4
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• pp.96-103
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• 2005

We designed the compound CVT(Continuously Variable Transmissions) by combining power circulation mode and power split mode, which have been proposed for connecting 2K-H I differential gear to the V- belt type CVU(Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments for efficiency, speed ratio, power flow, and power transmission ratio. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.3
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• pp.224-234
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• 2016

This study developed the conductivity pattern of solid surface using laser direct pattern and compound polymer material technology. For development direct patterning system of solid surface, we used the laser power stabilizer, the dynamic focusing, 3D scanner S/W and the auto aligning techniques. Also For conductivity pattern, we are developed compound polymer material with additive by electro-less plating. These technologies are already used commercially. However operation and control integrated system for direct patterning of solid surface are not yet developed. The objective of this paper is to introduce the laser direct structuring for simple process improvement instead complex PCB process, and develop the operating stability and integration system. Also we implemented new application of laser direct structuring through sample manufacture.

• Journal of Food Hygiene and Safety
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• v.22 no.4
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• pp.346-352
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• 2007

Contamination of aflatoxins(AFs) was monitored in 447 compound feeds and 138 feed ingredients samples distributed in South KOREA in 2006 and 2007. The degree of $AFB_1\;and\;AFB_2$ contamination in compound feed was 20% and 3%, respectively. The levels of detection were ranged from 0.48 to 10.46 ppb for $AFB_1$ and from 0.25 to 0,42 ppb for $AFB_2$. Thirty eight percent of compound feeds were contaminated with $AFB_1$ at concentration between 0.43 and 5.52 ppb and $AFB_2$ was detected in 2% of compound feeds at levels ranging 0.26-0.40 ppb. The highest degree of $AFB_1$ contamination was observed in compound feeds for beef cattle (75%) followed by for dairy cattle (72%) and in bran among feed ingredients (30%). Bran exhibited the highest level of $AFB_1$contamination (3.1 ppb). Vegetable proteins and compound feeds for dog showed relative lower degree of contamination at 2.9 and 1.9 ppb, respectively. $AFG_1\;and\;AFG_2$ were not detected in any compound feeds and feed ingredients samples.

• Fire Science and Engineering
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• v.30 no.3
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• pp.55-61
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• 2016

In this study, to determine whether it is possible to apply Polyethylene (PE) compound pipe, which was developed to solve the problem caused by the corrosion of the fire protection piping currently in usein water based fire extinguishing systems, we performed an actual mockup fire test. Since no test standard was available related to the developed compound pipe, we compared and analyzed domestic and international technical materials and test standards and selected suitable fire test standards to evaluate the performance of the PE compound pipe. we applied two fire test standards to the PE compound pipe, viz. those for CPVC and metallic pipes, and conducted a total of 6 experiments to evaluate its performance. According to the results of the first and second fire tests based on the test standard for the CPVC pipe, neither the fitting nor the piping was damaged or deformed and no leakage was observed in the pressure test, which was performed for 5 minutes. For the fire test based on the metallic pipe test standard, a total of 4 experiments were conducted. The first two experiments were conducted to simulate the wet piping system. In the results of this fire test, neither leakage nor rupture was observed from the PE compound pipe and no damage was caused, such as the secession of the PE material. However, in the next two experiments, which simulated the dry system, the PE compound pipe suffered damage and rupture, including deformation before the fire fighting water was discharged. Therefore, we found that the piping performance of the PE compound pipe did not undergo any deterioration, including fusion, deformation, or damage, in the wet piping system simulated fire test.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.1-7
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• 2006

The Primary type of swinging motion in human movement is that which is characteristic of a pendulum. The two types of pendulums are identified as simple and compound. A simple pendulum consist of a small body suspended by a relatively long cord. Its total mass is contained within the bob. The cord is not considered to have mass. A compound pendulum, on the other hand, is any pendulum such as the human body swinging by hands from a horizontal bar. Therefore a compound pendulum depicts important motions that are harmonic, periodic, and oscillatory. In this paper one discusses and compares two algorithms of Newton's method(F = m a) and Euler's method (M = $I{\times}{\alpha}$) in compound pendulum. Through exercise model such as human body with weight(m = 50 kg), body length(L = 1.5m), and center of gravity ($L_c$ = 0.4119L) from proximal end swinging by hands from a horizontal bar, one finds kinematic variables(angle displacement / velocity / acceleration), and simulates kinematic variables by changing body lengths and body mass. BSP by Clauser et al.(1969) & Chandler et al.(1975) is used to find moment of inertia of the compound pendulum. The radius of gyration about center of gravity (CoG) is $k_c\;=\;K_c{\times}L$ (단, k= radius of gyration, K= radius of gyration /segment length), and then moment of inertia about center of gravity(CoG) becomes $I_c\;=\;m\;k_c^2$. Finally, moment of inertia about Z-axis by parallel theorem becomes $I_o\;=\;I_c\;+\;m\;k^2$. The two-order ordinary differential equations of models are solved by ND function of numeric analysis method in Mathematica5.1. The results are as follows; First, The complexity of Newton's method is much more complex than that of Euler's method Second, one could be find kinematic variables according to changing body lengths(L = 1.3 / 1.7 m) and periods are increased by body length increment(L = 1.3 / 1.5 / 1.7 m). Third, one could be find that periods are not changing by means of changing mass(m = 50 / 55 / 60 kg). Conclusively, one is intended to meditate the possibility of applying a compound pendulum to sports(balling, golf, gymnastics and so on) necessary swinging motions. Further improvements to the study could be to apply Euler's method to real motions and one would be able to develop the simulator.

• Proceedings of the Korean Society for Language and Information Conference
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• 1998.02a
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• pp.303-309
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• 1998

• Journal of Ginseng Research
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• v.37 no.1
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• pp.135-141
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• 2013

A rapid, sensitive and selective analytical method was developed and validated for the determination of compound K, a major intestinal bacterial metabolite of ginsenosides in human plasma. Liquid-liquid extraction was used for sample preparation and analysis, followed by liquid chromatography tandem spectrometric analysis and an electrospray-ionization interface. Compound K was analyzed on a Phenomenex Luna C18 column ($100{\times}2.00$ mm, 3 ${\mu}m$) with the mobile phase run isocratically with 10 mM ammonium acetate-methanol-acetonitrile (5:47.5:47.5, v/v/v) at a flow rate of 0.5 mL/min. The method was validated for accuracy (relative error <12.63%), precision (coefficient of variation <9.14%), linearity, and recovery. The assay was linear over the entire range of calibration standards i.e., a concentration range of 1 ng/mL to 1,000 ng/mL ($r^2$ >0.9968). The recoveries of compound K after liquid-liquid extraction at 1, 2, 400, and 800 ng/mL were $106.00{\pm}0.08%$, $103.50{\pm}0.19%$, $111.45{\pm}5.21%$, and $89.62{\pm}34.46%$ for intra-day and $85.40{\pm}0.08%$, $94.50{\pm}0.09%$, $112.50{\pm}5.21%$, and $95.87{\pm}34.46%$ for inter-day, respectively. The lower limit of quantification of the analytical method of compound K was 1 ng/mL in human plasma. The developed method was successfully applied to a pharmacokinetic study of compound K after oral administration in ten of healthy human subjects.