• Applied Microscopy
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• v.36 no.4
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• pp.251-258
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• 2006

Crystal-bearing cells are rarely encountered in the softwoods and their regular occurrence, e.g., in species of Abies, Picea, Ginkgo, and Pinus, is of considerable diagnostic significance. Thus, this study discusses the distribution and types of crystals in North American Abies species to provide additional information for wood anatomy and identification through light and scanning electron microscopies. Prismatic crystals, elongate crystal s, and styloids are identified, in descending order of frequency, in Abies concolor, A. grandis. and A. magnifica, A. nobilis (=A. procera), A. lasiocarpa, and A. amabilis but not in A. balsamea and A. fraseri. Differently from the other species, A. lasiocarpa shows the tendency of more elongate crystals and styloids than prismatic crystals. A. concolor contains crystal sands, prismatic crystals, elongate crystals, and styloids both in the axial and ray parenchyma cells, whereas the other species show prismatic crystals, elongate crystals, and styloids only in the ray parenchyma cells. Ray parenchyma cells containing crystal sand and axial parenchyma cells having crystal sand, prismatic crystals, elongate crystals, and styloids are probably reported here for the first time in A. concolor. In conclusion, the presence or absence of crystals appears to be the most powerful diagnostic character for separating A. concolor, A. grandis, and A. magnifica from A. nobilis (=A. procera), A. lasiocarpa, A. amabilits, A. balsamea, and A. fraseri.

• Korean Journal of Plant Taxonomy
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• v.38 no.2
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• pp.121-149
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• 2008

Taxonomic treatment and the identification key for 6 species and 4 varieties from the genus Asarum (Aristolochiaceae) in Korea were presented on the basis of the morphological analyses. Recently the taxonomy of the genus Asarum in Korea is controversial in the definition of species and the establishment of variation range. Our morphological studies supported that the species A. patens, A. misandrum and A. versicolor should be recognized as independent species by the unique morphological characters such as calyx lobes, stylar protuberance and leaf variegation. Second, A. sieboldii var. cornutum, A. koreanum, A. maculatum and A. sonunsanense, regarded as species or variety by different scholars, showed a close relationship with A. sieboldii by the similar calyx characters. Thus, new combinations, such as A. sieboldii for. cornutum, A. sieboldii for. koreanum, A. sieboldii for. maculatum and A. sieboldii for. sonunsanense, are proposed. And A. heterotropoides var. seoulense and A. heterotropoides var. mandshuricum also had a close relationship, thus, new combinations, A. mandshuricum for. seoulense, A. mandshuricum for. mandshuricum, are proposed. Furthermore, it is appropriate that A. heterotropoides var. heterotropoides, only distributed in Japan, is revised into A. heterotropoides as independent species by the unique character from the 2 varieties above. Consequently, the genus Asarum in Korea is classified into 3 species and 7 forma.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.157-164
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• 2011

It is very difficult problem to factorize composite number. Integer factorization algorithms, for the most part, find ($a,b$) that is congruence of squares ($a^2{\equiv}b^2$(mode $n$)) with using factoring(factor base, B) and get the result, $p=GCD(a-b,n)$, $q=GCD(a+b,n)$ with taking the greatest common divisor of Euclid based on the formula $a^2-b^2=(a-b)(a+b)$. The efficiency of these algorithms hangs on finding ($a,b$). Fermat's algorithm that is base of congruence of squares finds $a^2-b^2=n$. This paper proposes the method to find $a^2-b^2=kn$, ($k=1,2,{\cdots}$). It is supposed $b_1$=0 or 5 to be surely, and b is a double number. First, the proposed method decides $k$ by getting kn that satisfies $b_1=0$ and $b_1=5$ about $n_2n_1$. Second, it decides $a_2a_1$ that satisfies $a^2-b^2=kn$. Third, it figures out ($a,b$) from $a^2-b^2=kn$ about $a_2a_1$ as deciding $\sqrt{kn}$ < $a$ < $\sqrt{(k+1)n}$ that is in $kn$ < $a^2$ < $(k+1)n$. The proposed algorithm is much more effective in comparison with the conventional Fermat algorithm.

• International Journal of Railway
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• v.2 no.2
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• pp.70-79
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• 2009

An optimal driving strategy of a train in a long journey on a nonsteep track has four phases: an initial power phase, a long hold speed phase, a coast phase and a final brake phase. The majority of the journey is speed holding. On a track with steep gradients, it becomes necessary to vary the strategy around steep sections of track because it is not possible to hold a constant steep on steep track. Instead we must interrupt the speed hold phase with a power phase. The aim of this paper is to show that there is a unique power phase that satisfies the necessary conditions for an optimal journey. The problem is developed and solved for various cases, from a simple single steep gradient to a complicated multiple steep gradient section. For each case, we construct a set of new conditions for optimality of the power phase that minimises the energy used during the power phase subject to a weighted time penalty. We then use the new necessary conditions to develop a calculate scheme for finding an optimal power phase for a steep incline. We also present an example to confirm the uniqueness of an optimal power phase.

• IMMUNE NETWORK
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• v.9 no.4
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• pp.133-137
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• 2009

We have recently shown that activin A, a member of TGF-$\beta$ superfamily, stimulates mouse B cells to express IgA isotype but other isotypes. In the present study, we further characterized effects of activin A on B cell growth and IgA expression. We found that activin A did not have effect on LPS-stimulated cell viability. In parallel, CFSE staining analysis revealed that activin A did not alter cell division. An increase of IgA secretion by activin A was completely abrogated by anti-activin A Ab but not by anti-TGF$\beta$1 Ab. In the same conditions, no other isotypes are significantly affected by each antibody treatment. Finally, activin A, as similar to TGF-$\beta$1, increased IgA secretion by mesenteric lymph node cells. These results suggest that activin A can specifically stimulate IgA response, independent of TGF-$\beta$ in the gut.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.125-134
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• 2016

We propose an efficient high voltage level shifter for a high side Buck converter driving a light-emitting diode (LED) lamp. The proposed circuit is comprised of a low voltage pulse width modulation (PWM) signal driver, a coupling capacitor, a resistor, and a diode. The proposed method uses a property of a PWM signal. The property is that the signal repeatedly transits between a low and high level at a certain frequency. A low voltage PWM signal is boosted to a high voltage PWM signal through a coupling capacitor using the property of the PWM signal, and the boosted high voltage PWM signal drives a p-channel metal oxide semiconductor (PMOS) transistor on the high side Buck converter. Experimental results show that the proposed level shifter boosts a low voltage (0 to 20 V) PWM signal at 125 kHz to a high voltage (370 to 380 V) PWM signal with a duty ratio of up to 0.9941.

• Bulletin of the Korean Mathematical Society
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• v.25 no.2
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• pp.179-183
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• 1988

In this paper we study a $C^{*}$-dynamical system (A, G, .alpha.) where A is a UHF-algebra, G is a finite abelian group and .alpha. is a *-automorphic action of product type of G on A. In [2], A. Kishimoto considered the case G= $Z_{n}$, the cyclic group of order n and investigated a condition in order that the fixed point algebra $A^{\alpha}$ of A under the action .alpha. is UHF. In later N.J. Munch studied extremal tracial states on $A^{\alpha}$ by employing the method of A. Kishimoto [3], where G is a finite abelian group. Generally speaking, when G is compact (not necessarily discrete and abelian), $A^{\alpha}$ is an AF-algebra and its ideal structure was well analysed by N. Riedel [4]. Here we obtain some conditions for $A^{\alpha}$ to be UHF, where G is a finite abelian group, which is an extension of the result of A. Kishimoto.oto.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.146-149
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• 2006

In many previous studies, a prestressed concrete column has a larger flexural strength, shear strength and restoring force than a RC column. Recently, a precast prestressed concrete column is rising up a very rational column structure in that a economic aspect. In a precast prestressed concrete column, it makes in a factory. So, it needs a small construction site and acquires a higher durability than a cast in place concrete column. Seven precast concrete columns were tested under a constant axial load and a cyclically reversed horizontal load to investigate the performance. It is designed with a hollow section and consisted of 4 segments. The main variables of the test were a amount of prestressed, a type of joints and a boding type of strands. The test results show that the performance of a precast prestressed concrete column; failure mode, maximum load, energy dissipation and stiffness degradation.

• Korean Journal Plant Pathology
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• v.11 no.2
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• pp.151-157
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• 1995

국내에서 분리한 20종의 Alternaria 277개 균주를 사용하여 Alternaria 진균소독인 altenuene(ALT), altertoxin-I(ATX-I) 및 tenuazonic acid(TA)의 in vitro에서의 생성능과 그 분포를 조사하였다. 각 사용균주를 200g의 살균된 쌀배지에 접종하여 $25^{\circ}C$에서 3주간 배양하였다. Alternaria 배양체들을 methanol로 추출하고 용매분획과 TLC 및 HPLC분석을 통하여 순화하였다. A. alternata와 그와 형태적으로 유사한 A. kikuchiana, A. longipes 및 A. mail는 비록 종간 및 종내의 균주간에 생성량의 차이는 매우 다양하였지만 TA를 비롯한 5종의 진균독소를 모두 생성하였다. A sesami와 A. sesamicola는 4종의 진균독소(AOH, AME, ALT, ATX-I)를 생성하였고 A. cucumerina, A. dauci, A. macrospora, A. porri, A. solani, A. tagetica와 A. zinniae와 같은 대형분생포자와 긴 beak를 형성하는 7종의 Alternaria균들은 AOH와 AME만을 생성하였다. A. brassicicola, A. helianthi, A. panax, A. radicina 및 A. raphani등 5종의 Alternaria는 5종의 진균 독소를 모두 생성하지 않았다.

• Journal of Industrial Technology
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• v.34
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• pp.21-26
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• 2014

The effect of refrigerant R-134a and R-430a on the performance of refrigeration equipment for R-134a is investigated. Refrigeration effect, compression work and coefficient of performance of refrigeration equpment for both R-134a and R-430a are obtained by experimentation. These performances comparison between R-134a and R-430a is made in case of the maximum load. Refrigeration effect for R-134a and that for R-430a is almost equal while compression work for R-134a is less than that for R-430a. Consequently it shows that coefficient of performance for R-134a is relatively 11% higher than that for R-430a.