• 대한수학회보
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• 제59권4호
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• pp.1045-1067
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• 2022

Given a graph G, a {1, 3, …, 2n-1}-factor of G is a spanning subgraph of G, in which each degree of vertices is one of {1, 3, …, 2n-1}, where n is a positive integer. In this paper, we first establish a lower bound on the size (resp. the spectral radius) of G to guarantee that G contains a {1, 3, …, 2n-1}-factor. Then we determine an upper bound on the distance spectral radius of G to ensure that G has a {1, 3, …, 2n-1}-factor. Furthermore, we construct some extremal graphs to show all the bounds obtained in this contribution are best possible.

• Bulletin of the Korean Chemical Society
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• 제23권12호
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• pp.1749-1753
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• 2002

The effect of concentration fluctuations on the changes of azimuth and ellipticity are analytically obtained in a binary chiral liquid mixture, when the incident light is completely linearly polarized above (or below) the horizontal at 45°. The important results are as follows;(1) When the binary liquid is in the critical region far from the cr5itical point, the ellipticity change is proportional to isothermal compressibility factor and the fifth order of frequency and shows the logarithmic divergence. (2) In the case that the system is in the critical region far from the critical point, the azimuth change is solely due to the molecular contribution. As the system approaches to the critical point, the effect of fluctuations becomes important. If it is in the extreme close to the critical point, the term due to the concentration fluctuations is comparable to or larger than the molecular contribution.

• Steel and Composite Structures
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• 제3권3호
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• pp.199-212
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• 2003

An experimental investigation of lightweight aggregate and foamed concrete contribution to the ultimate strength capacity of square and rectangular steel tube sections is presented in this study. Thirty-four simply supported beam specimens, 1000-mm long, filled with lightweight aggregate and foamed concretes were tested in pure flexural bending to calculate the ultimate moment capacity. Normal concrete-filled steel tubular and bare steel sections of identical dimensions were also tested and compared to the filled steel sections. Theoretical values of ultimate moment capacity of the beam specimens were also calculated in this study for comparison purposes. The test results showed that lightweight aggregate and foamed concrete significantly enhance the load carrying capacity of steel tubular sections. Furthermore, it can be concluded from this study that lightweight aggregate and foamed concretes can be used in composite construction to increase the flexural capacity of the steel tubular sections.

• 한국산학기술학회논문지
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• 제19권2호
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• pp.516-529
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• 2018

기업의 사회적 책임에 대한 인식과 요구가 증대되면서, 사회적 기여를 위한 기업의 활동이 다양해지고 있는 추세이다. 그럼에도 불구하고, 정기적으로 실시하는 관련 설문 조사에 따르면 기업의 사회 공헌활동에 대해 국민이 만족하지 못하는 것으로 나타났으며, 기업과 국민의 사회공헌활동에 대한 관점이 다른 것을 파악할 수 있었다. 이에 따라 다양한 사회공헌활동을 구체적으로 분류하여 사회에 미치는 영향을 파악하고자 한다. 본 연구에서는 기업 사회공헌활동과 성과에 대한 연관성을 파악하고자 사회공헌활동을 "사회문화적자원 활동", "사회간접적자원 활동" 및 "경제적자원 활동" 총 3가지 요인으로 분류하고, 요인별로 기업 간 연계활동과 지역발전성과에 미치는 영향을 파악하였다. 분석결과, 첫째, '사회문화적자원'과 '사회간접적자원' 활동은 지역 내 '기업 간 연계 활동'에 정(+)의 영향을 미치는 것으로 나타났다. 둘째, '지역 내 기업 간 연계' 활동이 활발할수록 '지역발전성과'에 정(+)의 영향을 미치는 것으로 나타났다. 셋째, '경제적자원' 활동은 '지역발전성과'에 정(+)의 영향을 미치는 것으로 나타났으며, 넷째, '사회문화적자원'과 '사회간접적자원' 활동은 지역 내 기업 간의 연계를 통해 '지역발전성과'에 간접적인 정(+)의 영향을 미치는 것으로 나타났다. 본 연구를 바탕으로 기업의 사회공헌활동과 성과에 대한 연관성을 정량적으로 파악하고 제시하였다.

• 한국토양비료학회지
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• 제44권5호
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• pp.722-726
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• 2011

The management standard on soil conditions in 'Fuji' apple to produce high quality fruit were not yet made. Therefore, this study was carried out to investigate the optimum soil environmental conditions of ten contents on production of high quality fruit in 'Fuji' apple. The soil and fruit characteristics were analyzed at total 60 orchards in major apple producing areas such as Chungju, Moonkyeung, yeongju, andong, yeosan and yeongcheon (10 orchards an area). The soil environmental factors affected fruit weight was highest relative contribution in saturated hydraulic conductivity of 36.5%. The bulk density and soil pH were low as relative contribution. The fruit weight was influenced by soil physical properties more than soil chemical properties. The soil environmental factors affected sugar content were hydraulic conductivity of 28.3% and organic matter content of 18.2%. The cultivation layer depth and soil pH were low as relative contribution. The fruit coloring was highest relative contribution in saturated hydraulic conductivity 55.9%. while soil pH, cation and soil texture were low. Fruit coloring was high influenced over 70% by soil physical properties. Finally, relative contribution on fruit quality related with sugar content, fruit weight, and coloring were high influenced by saturated hydraulic conductivity of 21.% and organic matter content of 18.7% but bulk density and cultivation layer depth were low relative contribution. The fruit growth and saturated hydraulic conductivity in 'Fuji' apple were very closely related. Therefore, orchard soil management to produce high quality fruit was very importance drainage management and organic matter application. We concluded that scientific soil management is possible by qualifiable of soil management factors.

• 통합자연과학논문집
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• 제10권2호
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• pp.85-94
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• 2017

Fibroblast growth factor receptor (FGFR) belongs to the family of receptor tyrosine kinase. They play important roles in cell proliferation, differentiation, development, migration, survival, wound healing, haematopoiesis and tumorigenesis. FGFRs are reported to cause several types of cancers in humans which make it an important drug target. In the current study, HQSAR analysis was performed on a series of recently reported 1H-Pyrazolo [3,4-b]pyridine derivatives as FGFR antagonists. The model was developed with Atom (A) and bond (B) connection (C), chirality (Ch), hydrogen (H) and donor/acceptor (DA) parameters and with different set of atom counts to improve the model. A reasonable HQSAR model ($q^2=0.701$, SDEP=0.654, NOC=5, $r^2=0.926$, SEE=0.325, BHL=71) was generated which showed good predictive ability. The contribution map depicted the atom contribution in inhibitory effect. A contribution map for the most active compound (compound 24) indicated that hydrogen and nitrogen atoms in the side chains of ring B as well as hydrogen atoms in the side chain of ring C and the nitrogen atom in the ring D contributed positively to the activity in inhibitory effect whereas, the lowest active compound (compound 04) showed negative contribution to inhibitory effect. Thus results of our study can provide insights in the designing potent and selective FGFR kinase inhibitors.

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1525-1530
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• 2004

Mutagen X (MX) exists in our drinking water as the bi-products of chlorine disinfection. Being one of the most potent mutagen, it attracted much attention from many researchers. MX and its analogs are synthesized and modeled by quantitative structure activity relationship (QSAR) methods. As a result, factors affecting this class of compounds have been found to be steric and electrostatic effects. We tried to collect all the data available from the literature. With both CoMFA and CoMSIA various combinations of physiochemical parameters were systematically studied to produce reasonable 3-dimensional models. The best model for CoMFA gave $q^2$ = 0.90 and $r^2$ = 0.97, while for CoMSIA $q^2$ = 0.85 and $r^2$ = 0.94. So the models seem to be reasonable. Unlike previous result of CoMFA, in our case steric parameter alone gave the best statistics. Although the steric contribution was found to be the most important in both CoMFA and CoMSIA, steric parameter along with electrostatic parameter produced slightly better model in CoMSIA. Overall, steric contribution is clearly the most important single factor. However, when we compare chlorine and bromine substitution, chlorine substitution can be more mutagenic. This indicates that other factors such as electrostatic effect also influence the mutagenicity. From the contour maps, steric contribution seems to be focused on rather small area near C6 substituent of the furanone ring, rather than C3 substituent. Therefore the locality of steric contribution can play a significant role in mutagenicity.

• Journal of Power Electronics
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• 제4권1호
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• pp.18-27
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• 2004

The output storage capacitor of the PFC converters is commonly designed for the selected hold-up time or the allowed output ripple voltage percentage. Nevertheless, this output capacitor is a main contribution factor to the PFC system stability. Moreover, seeking for a minimum output storage capacitor that assures the PFC desired operation under all condition, and providing the advantage of a small size and low cost is the main interesting target for engineering. Therefore, in this issue the design steps of the PFC converter have been discussed depending on three choices, output ripple, hold-up time, and stability. It is cleared that any design must take the minimum required storage capacitor for stability prospective as step-l in deign, then apply for any other specification like hold-up time or ripple percentage.

• ETRI Journal
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• 제33권1호
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• pp.110-120
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• 2011

As information technology rapidly develops and the period required to enter new technology shortens, there emerges a wide variety of alternatives for consumers. When there are many alternatives in the market, users choose after making comparisons. This process of making comparisons is our research key. We established a research model to find a mixed effect that comes from new attitudes to technology adoption and alternative's continuous usage intention. The effect is revealed through a relative attractiveness (RA) factor to explain a user's process of comparison. We empirically test our research model in the new media services, such as mobile TV, web TV, and mobile IPTV. According to our research results, a continuous usage intention of an existing technology is an important factor to explain the adoption of a new technology. So, the contribution of our research is in finding a role for the RA factor in research in new technology adoption.

• Journal of Mechanical Science and Technology
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• 제17권2호
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• pp.254-268
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• 2003

The explicit formulation of the J-integral and the M-integral is constructed in terms of the stress intensity factor and the higher order stress coefficients for Mode II cracks under small or large scale yielding. Furthermore, the stress intensity factor and the higher order stress coefficients as well are computed with the aid of the two-state J- and the M-integral, which is found to be accurate and efficient. It is found that the contribution from the higher order singularities to the J-integral is closely related to the configuration of the plastic zone.