• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.156-161
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• 2000

Least Squares and Minimum Zone method are known for obtaining a datum or a continuous approximate function of measured data. This study is for a Minimum Zone algorithm for a circle, which is useful to obtain the exact roundness from the reference circle of measured data. The proposed method is compared with the Least Squares Limacon method and Chrystal-Peirce algorithm. A computational algorithm for the Minimum Zone circle is suggested and results in less roundness than the other two methods. This Minimum Zone circle method will be used for other geometrical measured data, such as plane or sphere for obtaining the exact flatness or sphericity.

• The Korean Journal of Ecology
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• v.15 no.1
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• pp.59-65
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• 1992

Pollen analysis to clear vegetational history of korea was carried out on the deposite taken from the pit of the miruksa site, south-western korea(36o00'18'N, 127o1'12'E, 10m in alt.). This area has been known as the cool temperate zone(southern zone) according to yim and kira(1975). But, now we can not found the original vegetation because the area has been disturbed severely and almost area changed to cultivated land.the area is one of the most developd area in early agricultural stage of korea. By the pollen diagram, three local pollen zones are distinguished in this site, bottom to surface, as following. is-Ⅰ :pinus-quercus zone (140∼120 cm, sample 1 and 2) is-Ⅱ :ulmus+zelkova zone(120∼84 cm, sample 3∼6) is-Ⅲ :pinus zone(84∼0 cm, sample 7 ∼13) is-Ⅰ is characterized by high values in frequences of pinus, the temperate conifer and quercus the cool temperate oak, and is-Ⅱ zone by the decrease of quercus and increase of ulmus and increase of ulman+zelkova as ravine forest elements, isⅢ zone is characterized by pinus, especially, based on data of sample no.9.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.6-8
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• 2004

The NdBaCuO superconductor samples were zone-melted in low oxygen partial pressure (1 % $O_2$＋99%Ar). The zone-melting temperature was decreased about 12$0^{\circ}C$ from 1, 06$0^{\circ}C$, the zone-melting temperature in air. Thus the loss of liquid phase (BaCu $O_2$and CuO) was reduced during the zone-melting process. The content of non-superconducting phase Nd422 in zone-melted NdBaCuO samples was clearly decreased and, therefore, the substitution of Nd for Ba was occurred. The superconductivity of zone-melted N $d_{1＋x}$B $a_{2－x}$C $u_3$ $O_{y}$prepared under low oxygen partial pressure was distinctively improved.d.d.d.

• Journal of Welding and Joining
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• v.7 no.4
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• pp.38-45
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• 1989

In this study, in order to evaluate the shape and the size of the plastic zone at the notch tip before stable crack growth, a newly developed technique for plastic strain measurement, that is, the recrystallization-etching technique was applied to observe the intense strain zone at the notch tip of weld HAZ. 1) The recrystallized specimens showed that the amount of the intense strain zone, more than 20% plastic zone, was quantitatively observed as the plane strain state during the growth of the plastic zone. 2) The behavior of plastic deformation at midsection are different for parent and weld HAZ. In addition, the micro crack initiation occurs at midsection, parent and weld HAZ when the crack opening displacement(COD) value is .delta.$_{t}$=0.4mm. 3) The plastic zone for parent proceeds in the forward direction at notch tip and for weld HAZ in the right and left direction at the notch tip. 4) The relation between plastic strain energy(Wp) and COD(.delta.$_{t}$) depended on yield stress, gradient and plastic strain size.ize.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.51-59
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• 2007

The waste bunker usually consists of waste entrance zone and waste pit. In this paper, the distributions of air flow, $NH_3$ concentration and $H_2S$ concentration in a waste bunker were investigated to prevent an odor generated in a waste pit from dispersing to the waste entrance zone by numerical method. Four cases were considered such that 1) the waste incinerators is operated, 2) the waste incinerators is stopped, 3) the waste incinerator is operated and the direction of a supply diffuser is $45^{\circ}$ upward, 4) the waste incinerator is stopped and the direction of a supply diffuser is $45^{\circ}$ upward. In case of 1), the fresh air from the waste entrance zone is exhausted smoothly to the main exhaust grill of the waste pit. It means that an odor dispersion to the waste entrance zone will not occur. However in case of 2), the induction of fresh air is so small and the supply air with an odor in waste pit can flow to the waste entrance zone. Therefore, an odor will be dispersed to the waste entrance zone. This paper shows the solution that the supply diffuser with the direction of $45^{\circ}$ upward is chosen. As a result in case of 3) and 4), an odor dispersion to the waste entrance zone does not occurred and on odor is exhausted smoothly to the auxiliary exhaust grill.

• Structural Engineering and Mechanics
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• v.15 no.3
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• pp.367-378
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• 2003

The magnitude of the plastic zone around the crack tip of DENT (Double Edge Notched Tension) specimen and the crack growth length under cyclic loading were measured by ESPI (Electronic Speckle Pattern Interferometry) system. The measured magnitude of plastic zone was compared with the proposed by Irwin and calculated by a nonlinear static method of MSC/NASTRAN. The measured crack growth length by ESPI system was also compared with the obtained data by the image analysis system. From the study, it is confirmed that the plastic zone and crack growth length can be measured accurately with the high-tech equipment (ESPI System).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.3
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• pp.201-207
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• 2008

The seasonal variation and vertical distribution of the marine algal community were investigated using the quadrat method from February 2006 to January 2007 at 10 sites in Gwangyang Bay, Korea. In total, 48 red, 17 brown, and 13 green algal taxa were identified. The algal vertical distribution in the intertidal zone was characterized by Ulva pertusa, while the upper tidal zone was dominated by Gelidium divaricatum. The middle zone was primarily composed of Enteromorpha linza, Sargassum thunbergii, and Chondracanthus intermedia, whereas Hizikia fusiformis, Sargassum thunbergii, Gelidium amansii, and Corallina pilulifera characterized the low tidal zone. Results of cluster analysis indicated that algal composition fell into two groups, which were composed of species in the inland and open sea. In conclusion, the number of species, diversity, and abundance of vegetation in this area were remarkably reduced compared to previous studies in Gwangyang Bay.

• International Journal of Highway Engineering
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• v.16 no.3
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• pp.109-117
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• 2014

PURPOSES : This study analyzes the available working time at work-zone on the Expressway in accordance to the new capacity manual. METHODS : Sensitivity analysis on variables were conducted to calculate the adjusted capacity at work-zone based on previous researches. RESULTS : The main factors which affect available working time at the work-zone were its capacity, number of lanes, terrain and lane width. Other factors have minimal effect on the available working time. Based on the analysis, a calendar of lane closures was suggested. CONCLUSIONS : A series of studies concluded that the capacity at work-zone in the new capacity manual reduced to 76-82% of the existing manual. As such, the available working time decreased. Furthermore, the factors affecting the available working time needs to be considered when making a plan to rehabilitate the distressed pavement.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.222-222
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• 2017

This study aimed to determine an optimal temperature of root zone for the chive cultivation in a greenhouse during the winter season that may raise the possibility of chive (Allium schoenoprasum L.) harvest any time year-round by reducing energy consumption. The maximum and minimum temperatures of root zone were 26.8 and $19.8^{\circ}C$ for the R-Z20, 28.3 and $23.6^{\circ}C$ for the R-Z25 and 22.4 and $14.3^{\circ}C$ for the control. The highest fresh weights of shoot and root, plant height, root length and stem diameter were observed in the R-Z20 treatment. There was no significant difference in the growth between the R-Z25 and control treatment. These results suggest that the optimal temperature of root zone is $20^{\circ}C$ for the chive cultivation in the greenhouse during winter season.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.64-72
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• 1993

Analytical models for the prediction of the size of hardened zone in laser surface hardening are presented. The models are based on the solutions to the problem of three-dimensional heat flow in plates with infinite thickness. The validity of the model was tested on medium carbon steel for Gaussian mode of beam. Then the model for rectagular beam was used for the predicition of the size of hardened zone on various hardening process parameters. From the calculation results it appeared that the size and shape of the hardened zone are strongly dependent on process parameters such as beam mode, beam size, and traverse speed.