• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.277-281
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• 2004

The following paper proposes the new design of digital sine wave generator which allows users to define the phase shift of the out put sinewave according to user's demands. This new sinewave generator will have 2 outputs, cos(${\omega}_0n$) and cos(${\omega}_0n$+${\phi}$) The design of the new system starts from the construction of discrete time system with impulse response as cos(${\omega}_0n$) in a pair of conjugate complex poles and a pair of zeros at the origin and the real axis. If users want to make a phase shift of sign wave, users can change the position of zero at the real axis. The results of the experiment have shown that the new design of sign wave generator has generated sine wave with the correct phase shift according to the theory.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.139-145
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• 2000

The mechanism of the inner resistance in a rubber crawler system has been investigated to reduce the power requirement (Kitano et al. 1994). The rolling resistance of the track roller, which is one of the major inner resistances, was measured for seven different vertical loads. The rolling resistance changed periodically and could be classified into three types. In case of the vertical load less than 500N, the rolling resistance was almost constant. For the vertical load greater than 500N, the maximum value of the rolling resistance increased. Further more in case of the vertical load greater than 1200N, negative resistance appeared. Analytical simulation of the travel resistance based on experimental results and static equilibrium equations derived from three-dimension mechanical model for the rubber crawler system. It was found that the simulation method was carried out to evaluate the travel resistance occurred by the rolling resistance of the track roller. The rolling resistance for each track roller arrangement and effects of the lug phase in the right and left rubber crawler could be estimated quantitatively.

• Journal of Radiation Protection and Research
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• v.41 no.4
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• pp.328-332
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• 2016

Background: Boron Neutron Capture Therapy (BNCT) is a new radiation therapy. In BNCT, there exists some very critical problems that should be solved. One of the severest problems is that the treatment effect cannot be known during BNCT in real time. We are now developing a SPECT (single photon emission computed tomography) system (BNCT-SPECT), with a cadmium telluride (CdTe) semiconductor detector. BNCT-SPECT can obtain the BNCT treatment effect by measuring 478 keV gamma-rays emitted from the excited state of $^7Li$ nucleus created by $^{10}B(n,{\alpha})$ $^7Li$ reaction. In the previous studies, we investigated the feasibility of the BNCT-SPECT system. As a result, the S/N ratio did not meet the criterion of S/N > 1 because deterioration of the S/N ratio occurred caused by the influence of Compton scattering especially due to capture gamma-rays of hydrogen. Materials and Methods: We thus produced an arrayed detector with two CdTe crystals to test cross talk phenomenon and to examine an anti-coincidence detection possibility. For more precise analysis for the anti-coincidence detection, we designed and made a collimator having a similar performance to the real BNCT-SPECT. Results and Discussion: We carried out experiments with the collimator to examine the effect of cross talk of scattering gamma-rays between CdTe elements more practically. As a result of measurement the coincidence events were successfully extracted. Conclusion: We are now planning to carry out evaluation of coincidence rate from the measurement and comparison of it with the numerical calculations.

• Journal of the Korean Operations Research and Management Science Society
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• v.16 no.2
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• pp.164-176
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• 1991

This paper considers the model of a k-out-of-n :G system with non-identical components which are subject to both forced and planned outages. For the forced outages, it assumes that there are the independent and common-cause outage events causing component failures. Then, the objective is to derive the upper and lower bounds on the mean operating time between system failures in the ample-server model. In addtion, the mean system failure times are also considered.

• Journal of Environmental Science International
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• v.21 no.2
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• pp.189-202
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• 2012

Power spectral analysis for $PM_{10}$ observed at 10 cities in the Korean Peninsula from 2004 to 2010 was carried out to examine the spatial and temporal features of $PM_{10}$ evolution cycle. The power spectrum analysis proposed 9 typical cycles (0.5 day, 1day, 5.4day, 8~10day, 19~21day, 26day, 56day, 180day and 365day) for $PM_{10}$ evolution and the cycles are strongly associated with dilution and transportation due to the meterological influence. The spectrum intensity of 5.4day and 26day $PM_{10}$ evolution cycles mainly depend on the advection cycles of synoptic pressures system and long-term variation of climatological forcing, respectively. The intensity of $PM_{10}$ evolution with longer temporal cycles than one day tends to be stronger in La ni$\tilde{n}$a period in comparison with that in El ni$\tilde{n}$o period. Mean of typical intensity of $PM_{10}$ evolution in La ni$\tilde{n}$a period estimated to be 30% larger than El ni$\tilde{n}$o period. Thus the global scale meteorological phenomena such as El ni$\tilde{n}$o and La ni$\tilde{n}$a also can influence the variation of wind system in the Korean Peninsula and $PM_{10}$ evolution. but global scale forcing tends to influence different manner for $PM_{10}$ evolution in accordance with its temporal cycles.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.144-148
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• 2002

This study was carried out to investigate sewage treatment efficiencies using water hyacinth (Eichhornia crassipes) and watercress (Oenanthe Javanica). In the hyacinth system about 30% of COD introduced was removed during 2 days of hydraulic retention time, and about 30$\sim$50% of COD was removed in the watercress system during 1.2$\sim$2 days of hydraulic retention time. Therefore, COD loading of $76\sim170$ kg $COD/ha{\cdot}day$ was removed during 2$\sim$3 days of hydraulic retention time at the 0.18 $m^2$ area in the water hyacinth-watercress continuous system. Also 40$\sim$50% of N and P in the sewage were removed in the tested water hyacinth-watercress system Although COD, N and P concentrations in the final effluent were still higher than the limits of waste discharge, applicability of this waste water treatment system should be further investigated as an alternative method far small scale sewage treatments.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.284-290
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• 1993

The soap-free emulsion polymerization was carried out for Styrene/Butadiene system with Acrylonitrile as hydrophilic comonomer and KPS as initiator. Under the condition of below 50% conversion, the dependence of Rp on $[AN]^n$ and $[KPS]^n$ was found to be n=1.617-1.050 and n=0.83-0.96 for [AN] and [KPS], respectively. The effect of $[AN]^n$ and $[KPS]^n$ on particle number density (Np) was determined to be n=1.533 and n=0.733, respectively. The highest conversion was obtained under the conditions of pH=5 and ratio of total monomer (g) to water (g)=0.5. The mechanical properties of SBR obtained in this experiment were shown to be inferior to commercial SBR in terms of tensile strength, 300% modulus and elongation. It was found that cure rate of SBR prepared in this experiment was faster than that of commercial SBR.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.10
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• pp.91-98
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• 2007

This paper describes the development of the calibration system for a multi-axis force/moment sensor and its uncertainty evaluation. This calibration system can generate the continuous forces (${\pm}Fx,\;{\pm}Fy$ and ${\pm}Fz$) and moments (${\pm}Mx,\;{\pm}My$ and ${\pm}Mz$). Many kinds of multi-axis force/moment sensors in industries should be carried out the characteristic test or the calibration with the calibration system that can generate the forces and the moments. The calibration systems have been already developed are the disadvantages of the low capacity, the generation of step forces(10N, 20N ...) and step moments(1Nm, 2Nm ...) with weights, the high coasts in manufacture and so on. In this paper, the calibration system for a multi-axis force/moment sensor that can generate the continuous three forces and three moments was developed. Their ranges are $0{\sim}2000N$ in all force-directions and $0{\sim}400Nm$ in all moment-directions. And the system was evaluated in the expanded relative uncertainty. They were ${\pm}0.0004$ in all forces ${\pm}Fx,\;{\pm}Fy$ and ${\pm}Fz$, and ${\pm}0.0004$ in all moments ${\pm}Mx,\;{\pm}My$ and ${\pm}Mz$.

• Archives of Pharmacal Research
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• v.7 no.2
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• pp.115-120
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• 1984

The crystals of bromhexine-HCl, $C_{14}$ H$_{21}$ N$_{2}$Br$_{2}$Cl, are orthohombic, space group Pca2 with a = 14.598(2)A, b=12.461(3)A, c =9 9.186(1) A and Z = 4. Intensity dat for 967 reflections (Fobs > 6.sigma.(F)) were collected on a Rigaku-Denki automatic four circle diffractometer. The structure was solved by the Patterson and Fourier methods. Refinements were carried out to the final R value of 0.082. The cyclohexane ring has a normal chair form and the benzene ring is planar. There are three independenet hydrogen bounds in the structure. One is an intermolecular hydrogen bond (N-H... Cl) and the others are intramolecular hydrogen bonds (N-H...Br, N$^{+}$-H...Cl$^{[-10]}$ ) Apart from the hydrogen bounding system the molecules are held together in the crystal by van der Waals force.e.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.30 no.2
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• pp.90-100
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• 2012

This study centering on 10 village - Bangjuks analyzed multifunctionality value of village Bangjuks which have been main water treatment system in Korean traditional villages. On the basis of understanding the structure and character of components such as the well, common spring, village waterway and others which making water-flow and consisting of aquatic system in Korean traditional village Bangjuk, the conclusion as the instrumental device of social and ecological role and ecological watershed management, securing the ecosystem soundness of the damaged or deteriated aquatic ecosystem due to the industrialization and urbanization is as below; 1. The traditional village Bangjuk was environmentally friendly hydraulic system which gathers waterways of village into a point including sewage water, retains and flows out to village through agricultural waterway. Through this Bangjuk, they have managed sewage and rainfall runoff flowed out village efficiently. It is not only a detention system of water but a kind of eco-friendly system that flow out water into the rivers after reusing and filtering it. 2. Around five traditional villages and five villages after modernization, this study classified the types of village Bangjuk as three types considering geographic location, size, etc; marsh type of low swamp, high water -low rice field type of natural flow stucture, low water - high rice field type requiring artificial irrigation facility. All the five traditional villages were turned out to be marsh type of low swamp. Geoji, Sanjeri, Ma-am, Yangchon of the agricultural villages were high water-low rice filed type, and Sangchoenri village was classified low water-high rice field type. 3. This study checked up the function of water purification of village Bangjuk. In Wonteo and Geji villages affected by discharge of village sewer and domestic sewage, the efficiency of ammonia nitrogen($NH_3-N$) and total phosphorus(T-P) was 56~95%, which was high. In Sangcheonri and Sanjeri villages strongly affected by stall and farmland, the efficiency of suspended solids(SS) was 70~85%, and that of total nitrogen(T-N) and total phosphorus(T-P) was 5.3~65%. 4. A water purification system can be found out in the system of village Bangjuk that filter out village sewage and rainfall runoff flowed through the settle and filter of pollution source and denitrification of plants. Through this system of village Bangjuk, it must be used as the basic facilities for the ecological watershed management. The sewage management system of village Bangjuk as a eco-filter must be used and studied as an eco-friendly facility for the ecological watershed management around the subwatershed and catchment.