• Journal of Ecology and Environment
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• v.29 no.3
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• pp.287-293
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• 2006

We carried out pollen analysis and radiocarbon dating from sediments of Wangdeungjae moor (960 m a.s.l.) to clarify vegetation history of temperate broad-leaved deciduous forest zone of Mt. Jiri. Three local pollen zones and two sub-zones were recognized on the basis of variation in the palynofloral assemblage: I. Quercus zone (150-114 cm), II. Quercus-Pinus zone (114-43 cm): IIa. Quercus-Pinus subzone (114-83 cm), IIb. Quercus-Pinus-Herbs subzone (83-43 cm), III. Pinus-Quercus zone (43-27 cm). Radiocarbon date from sediment depth 111-116 cm was estimated $1,160{\pm}40yr$ B.P. From these results, overall vegetation around of Wangdeungjae moor and Mt. Jiri have changed from Q. mongolica dominant to steady decrease of Q. mongolica whereas steady increase of P. densiflora, finally abrupt increase of P. densiflora. 'Medieval Warm Period (MWP)' and 'Little Ice Age (LIA)' have not had an effect on change of vegetation around, at least, Mt. Jiri. But at maximum period of LIA, extension of grassland and steady increase of Pinus were recognized around the moor. After then, an abrupt increase of Pinus is supposed that vegetation change is reflected in human impact surging around foothills.

• Korean Journal of Remote Sensing
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• v.37 no.5_3
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• pp.1447-1460
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• 2021

Urbanization increases the amount of impervious surface and artificial heat emission, resulting in urban heat island (UHI) effect. Local climate zones (LCZ) are a classification scheme for urban areas considering urban land cover characteristics and the geometry and structure of buildings, which can be used for analyzing urban heat island effect in detail. This study aimed to examine the UHI effect by urban structure in Suwon and Daegu using the LCZ scheme. First, the LCZ maps were generated using Landsat 8 images and convolutional neural network (CNN) deep learning over the two cities. Then, Surface UHI (SUHI), which indicates the land surface temperature (LST) difference between urban and rural areas, was analyzed by LCZ class. The results showed that the overall accuracies of the CNN models for LCZ classification were relatively high 87.9% and 81.7% for Suwon and Daegu, respectively. In general, Daegu had higher LST for all LCZ classes than Suwon. For both cities, LST tended to increase with increasing building density with relatively low building height. For both cities, the intensity of SUHI was very high in summer regardless of LCZ classes and was also relatively high except for a few classes in spring and fall. In winter the SUHI intensity was low, resulting in negative values for many LCZ classes. This implies that UHI is very strong in summer, and some urban areas often are colder than rural areas in winter. The research findings demonstrated the applicability of the LCZ data for SUHI analysis and can provide a basis for establishing timely strategies to respond urban on-going climate change over urban areas.

• Development and Reproduction
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• v.5 no.2
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• pp.181-187
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• 2001

Seasonal changes and circadian rhythm of plasma prolactin(PRL) concentration in mammals are mediated by melatonin. Pinealectomy or denervation of the pineal gland produces an increase in plasma PRL level. In the rat placenta several members of the PRL family gene are expressed during the late pregnancy. However, the full spectrum of their expression mechanisms and regulatory factors are not elucidated yet. Present study aimed to investigate the local expression of the melatonin receptor la(Me $l_{la}$ ) gene and the effect of melatonin on expression of prolactin-like protein A(PLP-A), a member of the PRL-family gene in the rat placenta. According to the RT-PCR, northern blot and in situ hybridization experiments, Me $l_{la}$ gene was locally expressed in the rat placenta, Me $l_{la}$ mRNA was localized mainly in the placental junctional and labyrinth zones. Interestingly, junctional zone of the placenta showed strong expression of Me $l_{la}$ at daytime(16:00) than at nighttime(22:00). Melatonin agonist, chlorornelatonin decreased the PLP-A mRNA levels in the rat placenta. These results suggest that melatonin coupled with Me $l_{la}$ , may act as a regulation factor that mediates the expression of the PLP-A gene in the rat placenta.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.38-41
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• 2009

Debonding behavior of symmetric tilt bicrystal interfaces with <100> misorientation axis is investigated through molecular dynamics simulations. FCC single crystal copper is considered in each grain and the model is idealized as a grain boundary under mechanical loading. Embedded-Atom Method potential is chosen to calculate the interatomic forces between atoms. Constrained tensile deformations are applied to a variety of misorientation angles in order to estimate the effect of grain boundary angle on local peak stress. A new parameter of symmetric grain-boundary structure is introduced and refines the correlation between grain boundary angle and local peak stress.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.210-220
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• 2005

We have analyzed the stability for cut-slopes at main street 3-2 line section in Pa-ju local industrial complex. After studying an additional boring test, laboratory test and face mapping etc., we have determined the extent of reinforcement, slope inclinations and soil strength parameter from the analysis of test results. After changing the inclination of slopes for ground limit and carrying out the analysis of slope stability, we applied the Mass Nailing Method to the site because of need for reinforcement to soil and weathered rock slopes. In slope for soft and hard rock sections, we also reinforced the sections that are difficult to obtain the safety without reinforcement in alteration zone.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.3
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• pp.13-19
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• 2000

In the present study, a program for predicting thermal performance of an air cooled condenser is illustrated. Heat transfer equations of single phase and two phase flow are formulated into the form that is convenient to incorporate the local analysis method. The resulting equations are solved by temperature and mass correction methods. Empirical equations for both side fluids are incorporated in the caculation procedures. In order to compare the calculation results, superheat temperature of steam are varied. The tube length of superheated zone, wall temperature, temperature profile along the tube and steam qualities are predicted.

• Journal of Ocean Engineering and Technology
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• v.14 no.1
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• pp.44-51
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• 2000

Safety and integrity are required for reactor pressure vessels because they are operated in high temperature. There are single specimen method multiple specimen method and load ratio analysis method which used as evaluation of safety and integrity for reactor pressure vessels. In this study the fracture resistance curve(J-R curve) elastic-plastic fracture toughness($J_{IC}$) and material tearing modulus ($T_{mat}$) of SA 508 class 3 alloy steel used as reactor pressure vessel steel are measured and evaluated at room temperature 20$0^{\circ}C$ and 30$0^{\circ}C$ according to unloading compliance method and load ration analysis method. And then the comparison with experimental $J_{IC}$ and theoretical$J_{IC}$ by local fracture strain is managed.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.10
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• pp.530-536
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• 1999

This paper investigates effects of segmented poles on exciting forces such as cogging torque, BEMF, phase current, torque ripple and local forces. Cogging torque, BEMF and local force are determined by FEM analysis and phase current is calculated using voltage equations after determining BEMF and phase inductance. Effective dead zones at pole separations result in wider than the physical dead zones due to leakage field during magnetization. Due to the existence of dead zones, there exist additional exciting harmonics of the cogging torque which play adverse effect on vibration and noise performance. The magnitude of BEMF is decreased and the waveforms are also distorted depending on dead zone positions. Segmented poles inevitably cause uneven magnetic field distribution at pole separations which introduces additional harmonics of exciting forces which are detrimental to structural to structural resonances. They also decrease motor efficiency by reducing effective phase BEMF.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.8
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• pp.2491-2500
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• 1996

An experimental and analytical investigation is performed to study the buckling behavior of composite laminates with an embedded delamination. It is of particular interest to veryfy whether delamination growth cddurs with continuming deformation after buckling of composite laminates with an embedded delamination. Experiments are conducted for [0/sub 4///90/sub 8//0/sub 4/]/sub r/ laminates with delamination size in which local buckling mode governs buckling. Results show that delamination growth occurs in hgigher load after buckling and is accompanid by other damage mechanisms such as splitting. Also, it is found that transverse deformation before difurcation buckling is due to initial imperfection and structure such as plate with small bending stiffness is sensitive to that.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 1999.02a
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• pp.61-64
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• 1999

Dry winding is generally adopted in superconducting coils of an UPS system. In these kinds of coils a quench is often initiated by a disturbance such as wire motion that generates a highly localized normal zone in a superconducting wire. To fabricate the stable coils, stability of the superconducting wire should be touched. In this paper, a model for a transient stability analysis of the wire is suggested. The influence of a local disturbance, cooling, an external field and a stabilizer to superconductor ratio on the wire stability is investigated and discussed.