• 한국과학교육학회지
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• 제9권2호
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• pp.55-79
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• 1989

The first doctoral program for science education was opened on March 1984 at Seoul National University in Korea. As a faculty member of the University, this researcher investigated the status of doctoral program of foreign countries through interview with instractors and students by visitation of some institutes, participation of seminars, observation of tutoring, reading of theses and the related papers, in order to compare them and to design a new one for our purpose. The number of science education doctoral degree holders is estimated about 4000, among them 3000 doctoral degree holders are from USA since Columbia University Teachers College started in 1930s at first, and about 1000 doctors from other mainly European countries including Germany and England since 1970s. This study concentrated to the doctoral program for science education of Columbia University(USA), King's College London(UK), and Monash University (Australia),so that proposed a few aspects of development on doctoral program for science education in Korea.

• 한국임상수의학회:학술대회논문집
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• 한국임상수의학회 2009년도 춘계학술대회
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• pp.294-294
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• 2009

• Journal of Ginseng Research
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• 제12권2호
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• pp.145-152
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• 1988

Correlations between various morphological characteristics of Panax quinquefolium plants grown in Lytton, British Columbia, Canada were assessed for 1-through 4-year old plants. Root dry weight, the dependent variable, was found to be strongly related to leaf dry weight, leaf length and root length for 1-and 2-year old plants during the middle of the growing season. For 1- and 2-year old plants at the end of the growing season, root dry weight was found to be related to leaf dry weight, leaf length and stem dry weight. For 3 and 4-year old plants, root dry weight was found to be related to leaf dry weight, leaf length and stem dry weight. For 3- and 4-year old plants, root dry weight was found to be related to leaf dry weight. For practical considerations, this latter relationship provides a simple method for selecting superior plants from which seed can be harvested.

• Journal of Ginseng Research
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• 제12권1호
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• pp.53-62
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• 1988

A field experiment was conducted in the arid interior of British Columbia, Canada to assess the seasonal soil temperature and moisture regimes in an American ginseng garden. As a consequence of the man-modified microclimate (elevated shade canopy and surface covering of mulch), the growing environment of the crop was fundamentally altered when compared to adjacent agricultural growing environments. In the ginseng garden, soil temperatures were found to remain low throughout the growing season whereas soil moisture remained high when compared with the outside garden environment. These results indicate that even in the hot, arid environment of the interior of British Columbia, the growing of ginseng is undertaken in sub-optimal conditions for the major part of the growing season. This poses challenges for the producers of the crop to modify the architecture of the gardens to enhance the soil regime without creating a deleterious aerial environment.

• 대한안전경영과학회지
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• 제4권2호
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• pp.209-221
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• 2002

Machinability improvement by the use of liquid nitrogen in cryogenic machining has been reported in various studies. This has been mostly attributed to the cooling effect of liquid nitrogen. However, No study has been found in discussion on whether liquid nitrogen possesses lubrication effect in cryogenic cutting. In machining tests, cryogenic machining reduced the force component in the feed direction, indicating that the chip slides on the tool rake face with lower friction. This study also found that the effectiveness of LN2 lubrication depends on the approach how LN2 is applied regarding cutting forces related.

• 대한안전경영과학회지
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• 제4권2호
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• pp.223-235
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• 2002

This paper presents some indirect physical evidences indicating that reduced friction occurs in an economical cryogenic machining process, in which LN2 is applied selectively in well-controlled jets to the localized cutting zone. These evidences include cutting force components, tool wear rate and chip morphology. LN2 reduced the tool wear rate to a great extent and elongated the tool life up to four times compared to emulsion cooling. The friction reduction was further reflected in larger shear angle and less secondary deformation in the chip microstructures. This study also found that the effectiveness of LN2 lubrication depends on the approach how LN2 is applied.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.1118-1120
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• 1993

Fuzzy logic places a considerable burden on an inference engine for applications such as control or approximate reasoning. Various neural network architectures have been proposed to deal with the computational task, and yet, maintain flexibility in the desired traits of the final system. Recently, we introduced a trainable network architecture whose nodes implement weighted Yager additive hybrid operators for fuzzy logic inference in an approximate reasoning setting. In this paper we examine the utility of such networks for control situations. We show that they are capable of learning control functions which are piece-wise monotonic in each of the variables. The learning ability is demonstrated through an example.

• Natural Product Sciences
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• 제4권4호
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• pp.257-262
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• 1998

The extract of the aerial parts of Fumaria bastardii Bor. afforded 12 alkaloids belonging to the skeletally six different groups of the isoquinoline alkaloids. In this publication, the isolation and identification of protopine (1), corydaldine (2), oxyhydrastinine (3), (-)-fumaritine (4), (+)-fumariline (5), (-)-O-methylfumarophycine (12), (+)-bicuculline (10), $(-)-{\beta}-hydrastine$ (7), (-)-corlumine (11), (+)-tetrahydropalmatine (8), (-)-stylopine (6), and (+)-juziphine (9) are described. Their structures have been determined by using extensive spectroscopic techniques. This is the first report of the occurrence of these alkaloids in Fumaria bastardii of Turkish origin.

• Computers and Concrete
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• 제27권4호
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• pp.297-304
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• 2021

The hybrid Finite-Discrete Element (FDEM) approach combines aspects of both finite elements and discrete elements with fracture mechanics principles, and therefore it is well suited for realistic simulation of quasi-brittle materials. Notwithstanding, in the literature its application for the analysis of concrete is rather limited. In this paper, the proprietary FDEM code ELFEN is used to model concrete specimens under uniaxial compression and indirect tension (Brazilian tests) of different sizes. The results show that phenomena such as size effect and influence of strain-rate are captured using this modeling technique. In addition, a preliminary model of a slab subjected to dynamic shear punching due to progressive collapse is presented. The resulting fracturing pattern of the impacted slab is similar to observations from actual collapse.

• Computers and Concrete
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• 제23권2호
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• pp.121-131
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• 2019

Due to the heterogeneity nature of the concrete, it is difficult to simulate the hyperdynamic behaviour and crack trajectory of concrete material when subjected to explosion loads. In this paper, a 3D nonlinear numerical study was conducted to simulate the hyperdynamic behaviour of concrete under various loading conditions using Riedel-Hiermaier-Thoma (RHT) model. Detailed calibration was conducted to identify the optimal parameters for the RHT model on the material level. For the component level, the calibrated RHT parameters were used to simulate the failure behaviour of plain concrete (PC) slab under free air blast load. The response was compared with an available experimental result. The results show the proposed numerical model can accurately simulate the crack trajectory and the failure mode of the PC slab under free air blast load.