• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.1939-1944
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• 2011

The nucleophilic substitution reactions of bis(Y-aryl) chlorophosphates (1) with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at 35.0 $^{\circ}C$. The kinetic results of 1 are compared with those of Y-aryl phenyl chlorophosphates (2). The substrate 1 has one more identical substituent Y compared to substrate 2. The cross-interaction between Y and Y, due to additional substituent Y, is significant enough to result in the change of the sign of cross-interaction constant (CIC) from negative ${\rho}_{XY}$ = -1.31 (2) to positive ${\rho}_{XY}$ = +1.91 (1), indicating the change of reaction mechanism from a concerted $S_N2$ (2) to a stepwise mechanism with a rate-limiting leaving group departure from the intermediate (1). The deuterium kinetic isotope effects (DKIEs) involving deuterated anilines ($XC_6H_4ND_2$) show secondary inverse, $k_H/k_D$ = 0.61-0.87. The DKIEs invariably increase as substituent X changes from electron-donating to electron-withdrawing, while invariably decrease as substituent Y changes from electron-donating to electron-withdrawing. A stepwise mechanism with a rate-limiting bond breaking involving a predominant backside attack is proposed on the basis of positive sign of ${\rho}_{XY}$ and secondary inverse DKIEs.

• Biomolecules & Therapeutics
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• v.2 no.4
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• pp.331-335
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• 1994

As a part of the safety evaluation of Pseudomonas vaccine(CFC-101), antigenicity tests were carried out in guinea pigs and mice. In active systemic anaphylaxis(ASA) test, guinea pigs showed no sign or only moderate sign(1/5) when sensitized and challenged with up to 200 $\mu\textrm{g}$/kg. In homologous passive cutaneous anaphylaxis(PCA) test using guinea pigs, inoculation of CFC-101 alone did not produce CFC-101-specific antibody. When inoculated with 200 $\mu\textrm{g}$/kg plus adjuvant, challenge of 200 $\mu\textrm{g}$/kg produced PCA titer of 32(5/5) but challenge of 20 $\mu\textrm{g}$/kg did not produce CFC-101-specific antibody. In heterologous PCA test using mice, CFC-101-specific antibody was not detected when sensitized with CFC-101 alone. Some animals(3/12) showed positive PCA response when inoculated with 200 $\mu\textrm{g}$/kg plus alum. In passive hemagglutination (PHA) test, although no antibody was detected at 20 $\mu\textrm{g}$/kg, inoculation of 200 $\mu\textrm{g}$/kg alone or with alum produced positive response in all animals. This result has already been predicted because CFC-101 is a vaccine developed for the purpose of immunization. From the above results, it can be concluded that there is no adverse antigenic potential up to 10 times clinical dose of 200 $\mu\textrm{g}$/kg.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.8
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• pp.69-74
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• 2008

The propagation constant, which is defined for a double-positive (DPS) material of positive permittivity (${\varepsilon}'$) and permeability (${\mu}'$), is extended and derived for an epsilon-negative (ENG) material (${\varepsilon}'<0,\;{\mu}'>0$), a mu-negative (MNG) material (${\varepsilon}'>0,\;{\mu}'<0$), and a double-negative (DNG) material (${\varepsilon}'<0,\;{\mu}'<0$). By investigating how the permittivity loss (${\varepsilon}"$) and permeability loss (${\mu}"$) terms affect the propagation constant, we determine that the wave in the materials propagates as a right-handed (RH) triad or a left-handed (LH) triad. Regardless of the magnitudes of ${\varepsilon}"$ and ${\mu}"$, DPS and DNG materials become RH and LH media, respectively. However, ENG and MNG materials possess unusual characteristics that both materials become a RH medium when the sign of (${\varepsilon}'{\mu}"+{\varepsilon}"{\mu}'$) is positive and they become a LH medium when the sign is negative.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.6
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• pp.103-111
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• 1995

Drought index calculation based on the principal hydrological parameters, such as rainfall and reservoir storage, can estimate the duration and intensity of drought in irrigation reservoirs. It is difficult to build up a drought criteria since the conditions change variously by the reliability of rainfall. Because of the increasing water demands, it is urgent to prepare a generalized positive countermeasure to overcome drought. Water demands can at calculated but the estimation of drought characteristics, and the effective water management method can be established. The purpose of this study is to obtain a drought index and build up a data-base on the reservoir basins for establishing the fundamental hydrological data-base. This Index can observe the behavior of the WSI(Water Supply Index) and the component indices. The results summarized through this study are as follows. 1. WSI value of zero does not correspond to 100% in average due to the skewness in the probability distributions. 2. WSI is not a linear index; that is, given change in terms of water volume or percentage of average does not result in a proportional change on the WSI scale. 3. WSI is not always between the reservoir and the rainfall index in magnitude. This is only true if the component indices are of opposite sign. If they are of the same sign, the SWSI will often have a mangitude greater than either of the component indices. This is easily understood, because the concurrence of extreme values of the same sign for the two components is rarer than the occurrence of extreme values for either of the two components individually.

• Journal of Medicine and Life Science
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• v.19 no.3
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• pp.130-133
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• 2022

Several studies have reported a possible link between anti-aquaporin-4 antibody and vitamin B12 deficiency in neuromyelitis optica spectrum disorder (NMOSD). Bilaterally symmetric hyperintense signals on magnetic resonance imaging (MRI) of the posterior columns, called the inverted V sign, are a characteristic feature of subacute combined degeneration associated with vitamin B12 deficiency. We report a patient with anti-aquaporin-4 antibody-positive NMOSD and an inverted V sign on MRI of the spinal cord and address the association between anti-aquaporin-4 antibody and functional vitamin B12 deficiency.

• East Asian Economic Review
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• v.17 no.2
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• pp.129-159
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• 2013

Over the course of the recent global financial crisis, emerging economies experienced massive swings in capital inflows. In this paper, we estimate a VAR model to assess the impact of capital inflow shocks, which are identified using a set of sign restrictions, on house prices in Korea. We base the analysis on three alternative measures of capital inflows: net total inflows, net portfolio inflows and gross total inflows. The results suggest that capital inflow shocks have a significantly positive and persistent effect on real house prices. Although shocks to capital inflows are found to be substantially more important for Korean asset markets than for other OECD countries, their overall explanatory power is modest. Using regional house price data we also show that capital inflow shocks have an asymmetric effect on property markets across the seven largest Korean cities and across different parts of Seoul.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.315-318
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• 2003

This paper proposes a switching control method applicable to any affine, 2nd order nonlinear system with single input. The key contribution is to develop a control design method which uses a piecewise continuous Lyapunov function non-increasing at every discontinuous point. The proposed design method requires no restrictions except full state availability. To obtain a non-increasing, piecewise continuous Lyapunov function, we change the sign of off-diagonal term s of the positive definite matrix composing the former Lyapunov function according to the sign of the Inter-connection term. And we use the solution of inequalities which guarantee each Lyapunov function is non-increasing at any discontinuous point.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.513-528
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• 2014

This study examined effects of self-esteem, life satisfaction and gender on the sign needs which included self-presentation(presenting true-self and ideal-self) and social interaction (feeling connected and gaining approval) for Facebook use. Due to the significant interaction effects of gender, further statistical analyses were conducted. While there were negative relationships between self-esteem and self-presentation for male respondents, there were positive relationships between self-esteem and social interaction for female respondents. In addition, there were positive relationships between life-satisfaction and self-presentation for male respondents, but there was the only positive relationship between life satisfaction and presenting true-self for female respondents. Based on the study results, the study implications, limitations and future study were discussed.

• 대한예방의학회:학술대회논문집
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• 1994.02b
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• pp.142-149
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• 1994

Substitution of graphic representation for extensive lists of numerical statistical data is highly desirable by both editors and readers of medical journals, faced with an exploding abundance of contemporary medical literature. A novel graphic tool. the 'double-ring diagram', is described herein which permits visual representation of information regarding certain statistical variables used to describe the performance of a test or physical sign in the diagnosis of a disease. The diagram is relatively easy to construct on the basis of a number of primary data such as the prevalence and the true positive, true negative. false positive and false negative test results. These values are reflected in the diagram along with the values of other statistical variables derived from them. such as the sensitivity. specificity, predictive values for positive and negative test result. and accuracy. This diagram may be useful in visualizing a test's performance and facilitating visual comparison of performance of two or more tests.

• School Mathematics
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• v.8 no.1
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• pp.1-25
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• 2006

To be good at numeration is an important matter in learning mathematics. Unlike the 6-th curriculum, integers are introduced in middle school curriculum for the first time in the 7-th curriculum. Therefore, to help the students team integers systematically and thoroughly, it is necessary that we allow more space for process of introduction, process of operations and practice of operations in the 7-th curriculum text book than that of 6-th curriculum text book. As specific and systemic visualized teaching of operation is especially important in building the concept of operation, by using visualized teaching methods, students can understand the process of operation more fully and systematically. Moreover, students become proficient in operation of positive number and negative numbers by expending this learning process of operations to the operations used absolute value. In 7-th grade mathematics, the expression of positive numbers and negative numbers visually are useful for understanding of operations for numbers. But it is not easy to do so. In this paper we use arrows(directed segments) to express positive numbers and negative numbers visually and apply them to perform the operations for numbers. Using arrows, we can extend the method used in elementary school mathematics to the methods for operations of positive numbers and negative number in 7-th grade mathematics. By experiments, we can know that such processes of introduction for operations are effective and this way helps teachers teach and students learn.