• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.448-454
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• 2000

Piled multi-block system has been frequently adopted in the historic structures or monuments of cultural heritage. It is well known that such a structural system is very vulnerable to the earthquake shaking. If the structure is of slender type, then it may experience overturning at very low level intensity of ground shaking. One of the methods used to protect such structures from earthquake is seismic isolation system. But the behavior of multi-block systems mounted on the isolated basis is not well understood yet. In this paper we investigate the dynamic behavior of single slender rigid block mounted on the three different isolation systems, i.e., P-F system, FPS and LRB system. Sliding at the isolation interface of P-F system and FPS is formulated based on Coulomb friction. The mounted single block is assumed undergoing rocking or sticking only. Impacting of a single block is described using distinct element method (DEM). Free vibrations due to a prescribed initial conditions are studied. Responses to the harmonic excitation and earthquake motions are calculated

• Journal of the korean Society of Automotive Engineers
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• v.3 no.3
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• pp.30-38
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• 1981

The fatigue characteristics of Si-Mn spring steel (AISI 9260-H, JIS SUP-6) were investigated on several heat treatment conditions. Repeated impact loads of 10kg-cm and 15kg-cm energy were applied with a cam roller drop hammer type impact fatigue testing machine. Specimens were oil-quenched, and tempered at 350.deg. C, 450.deg. C and 500.deg. C, respectively. Results obtained in these experiments are summarized as follows.; 1) The fatigue life of the specimen is decreased as the magnitude of constant impact energy is increased, regardless of heat treatment. 2) Generally, the fatigue life of the specimen is decreased as the tensile strength of the materials is increased. 3) Within the limit of these experiments, the fatigue life showed abrupt decrease at the tempering temperature of about 400.deg. C 4) The fatigue life is increased as the initial value of applied stress intensity factor(K$_{1}$) is decreased. This tendency is apparent for the low tensile strength materials.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.632-638
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• 2000

This paper represents the characteristics of evapotranspiration rate (EVTR) and graft-taking of watermelon grafted seedlings in a graft-taking enhancement system using fluorescent lamps as artificial lighting source. Four air temperature levels of 23, 25, 27 and 29C, three humidity levels of 85, 90 and 95%R.H. and two photosynthetic photon flux (PPF) levels of 30 and 50 ${\mu}$mol m$\^$-2/ S$\^$-1/ were provided to investigate the effects of air temperature, relative humidity and light intensity on EVTR and graft-taking of grafted seedlings. EVTR of grafted seedlings increased with increasing air temperature and the passage of time after grafting. Also EVTR increased with decreasing relative humidity. As relative humidity decreased and air temperature increased, vapor pressure deficit increased and thus EVTR increased. It is required to maintain a low level vapor pressure deficit for suppressing EVTR of grafted seedlings during first 1-2 days after grafting. Therefore, less EVTR at initial stage after grafting would be adequate for smooth joining of the scion and rootstock.

• Textile Coloration and Finishing
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• v.13 no.6
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• pp.391-396
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• 2001

The physical properties and the dyeability of the easily dyeable polyester yarn(EDY) were investigated and compared with those of regular polyester (REG-PET). The EDY, copolymerized with small amount of polyethylene glycol(PEG), showed higher intensity of aliphatic CH peak in IR spectrum, lower density and lower compactness than those of the REG-PET from the analysis of IR, density gradient column and XRD respectively. In the physical properties, the EDY has lowers $T_g$, $T_m$, specific stress and initial modulus, and also has higher strain than that of the REG-PET The EDY can be dyed under atmospheric pressure and its dyeing Fate was faster than REG-PET due to low $T_d$, and this seems to be caused by the increased flexibility of Polymer chain in amorphous region of the EDY due to the copolymerization of PEG.

• Journal of Welding and Joining
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• v.13 no.4
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• pp.155-162
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• 1995

Redistribution of residual stress and its effects during fatigue crack propagates from tensile residual stress region in weldment are investigated. Tests are performed by using welded CCT specimens of structual rolling steel (SS400) and it makes fatigue crack propagate from tensile residual stress region. For this study tension-tension loading type is selected by external loading condition and magnetizing stress indicator is used correctly to measure redistribution of residual stress according to fatigue crack growth and number of loading cycles. From this result, it is proved that redistribution of residual stress is mainly consist of residual stress released by fatigue crack growth. When fatigue crack propagates from tensile residual stress region residual stress are redistributed and it makes fatigue crack growth rate largely increase. Fatigue crack growth rate is low in case of redistributed residual stress compare with initial distributed residual stress.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.690-693
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• 2003

An Si substrate (100) was oxidized at $400^{\circ}C$ in inductively coupled oxygen plasma. Interstitial oxygen was found in the Si substrate at the initial stage of oxidation by IR measurements. An x-ray rocking curve of Si substrates showed a lower peak intensity due to lattice distortion by the interstitial oxygen. The refractive index of thin oxides, below which interstitial oxygen existed in the Si substrate, was smaller than the refractive index of thick oxides, below which no interstitial oxygen existed. The interstitial oxygen was found by plasma oxidation using $O_{2}$ gas and $N_{2}O$ gas. The inductively coupled plasma oxidation using $N_{2}O$ gas was performed by atomic oxygen, not by molecular oxygen, indicating that atomic oxygen in plasma is responsible for the incorporation of interstitial oxygen.

• Journal of the Korean Society of Tobacco Science
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• v.21 no.2
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• pp.152-159
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• 1999

A CAB cDNA clone(pKGCAB) encoding the light harvesting chlorophyll a/b binding protein of the semi-shade plant, Korean ginseng(Panax ginseng C. A. Meyer) was isolated by the one-way path random sequencing of ginseng cDNA library clones and transgenic tobacco plants(Nicotiana tabacum NC82) were produced by the transformation of this ginseng CAB gene in use of Agrobacterium tumefaciens LBA4404. The CAB gene showed type 1 structure of LHCP-II, 84% similarity in nucleotide sequence and 92% in amino acid sequence to that of Nicotiana tabacum CAB40, respectively. Seed germination and initial growth of the transgenic tobacco plants transformed with the cDNA fragment were accelerated under low light intensity compared with those of normal tobacco plant, that may result from the higher light sensitivity of the transgenic plants than that of the normal.

• Journal of the Korean Applied Science and Technology
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• v.21 no.2
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• pp.182-189
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• 2004

On contraction of the muscles, marked changes in X-ray reflections are observed, suggesting that conformational changes of contractile molecules and the movement of myosin heads during muscle contraction. Time slice requires tension peak after the onset of stimulation and the height of tension peak depends on the number of twitch cycle. The muscles were stimulated by five successive stimuli at an interval of 80 ms started while the tension was still being exerted by the muscles. The intensity of $I_{11}$, $I_{10}$, $143{\AA}$ and $215{\AA}$ reflection measured with 5ms time resolution and is recorded in isometric tension. The peak height of $I_{11}$ and $143{\AA}$ intensity is changed after the onset of a stimulation $I_i$, and the length of twitch is shortened by successive twitches in the case of stimulation $T_i$. On the other hand, the peak height of In and $215{\AA}$ intensity starts to decrease at the 1st twitch and remains constant at low peak height without appreciable recovery during the contraction term. In the case of successive twitch stimulation, the myosin heads of muscle are once moved from their resting position and never returned to their initial position.

• Preventive Nutrition and Food Science
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• v.9 no.3
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• pp.227-231
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• 2004

Green, black and oolong teas were irradiated by $^{60}$ Co-gamma rays (0～10 kGy) and were investigated for detection of irradiation treatment using pulsed photostimulated luminescence (PPSL) and thermoluminescence (TL) during storage. Teas irradiated at 2.5 kGy or more showed a photon count of greater than 5000 counts/60 sec while the non-irradiated yielded only 650～1000 count/60 sec. Correlation coefficients between irradiation dose and photon counts/60 sec were 0.8951, 0.7934 and 0.9007 for green, black and oolong teas, respectively. The TL glow curves for minerals isolated from the non-irradiated teas were situated at about 30$0^{\circ}C$ with a low intensity, but for irradiated samples were approximately 15$0^{\circ}C$ with a high intensity. The TL ratios (TL$_1$/TL$_2$), calculated from values after initial radiation and then after re-irradiation of the teas, were below 0.1 for the non-irradiated samples and higher than 1.44 for all irradiated samples, enhanced the reliability of the identification results for TL. The signal intensity of PPSL and TL for irradiated teas decreased with the lapse of post-irradiation storage time at room temperature but was still distinguishable from that of the non-irradiated samples even after one year.

• Atmosphere
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• v.27 no.1
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• pp.105-118
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• 2017

This study assesses the performance of the Weather Research and Forecasting (WRF) model in reproducing regional climate over CORDEX-East Asia Phase 2 domain with different cumulus parameterization schemes [Kain-Fritch (KF), Betts-Miller-Janjic (BM), and Grell-Devenyi-Ensemble (GD)]. The model is integrated for 27 months from January 1979 to March 1981 and the initial and boundary conditions are derived from European Centre for Medium-Range Weather Forecast Interim Reanalysis (ERA-Interim). The WRF model reasonably reproduces the temperature and precipitation characteristics over East Asia, but the regional scale responses are very sensitive to cumulus parameterization schemes. In terms of mean bias, WRF model with BM scheme shows the best performance in terms of summer/winter mean precipitation as well as summer mean temperature throughout the North East Asia. In contrast, the seasonal mean precipitation is generally overestimated (underestimated) by KF (GD) scheme. In addition, the seasonal variation of the temperature and precipitation is well simulated by WRF model, but with an overestimation in summer precipitation derived from KF experiment and with an underestimation in wet season precipitation from BM and GD schemes. Also, the frequency distribution of daily precipitation derived from KF and BM experiments (GD experiment) is well reproduced, except for the overestimation (underestimation) in the intensity range above (less) then $2.5mm\;d^{-1}$. In the case of the amount of daily precipitation, all experiments tend to underestimate (overestimate) the amount of daily precipitation in the low-intensity range < $4mm\;d^{-1}$ (high-intensity range > $12mm\;d^{-1}$). This type of error is largest in the KF experiment.