• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제9권2호
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• pp.91-97
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• 2005

If ${\beta}\;>\;1$, then every non-negative number x has a ${\beta}-expansion$, i.e., $$x\;=\;{\epsilon}_0(x)\;+\;{\frac{\epsilon_1(x)}{\beta}}\;+\;{\frac{\epsilon_2(x)}{\beta}}\;+\;{\cdots}$$ where ${\epsilon}_0(x)\;=\;[x],\;{\epsilon}_1(x)\;=\;[\beta(x)],\;{\epsilon}_2(x)\;=\;[\beta(({\beta}x))]$, and so on ([x] denotes the integral part and (x) the fractional part of the real number x). Let T be a transformation on [0,1) defined by $x\;{\rightarrow}\;({\beta}x)$. It is well known that the relative frequency of $k\;{\in}\;\{0,\;1,\;{\cdots},\;[\beta]\}$ in ${\beta}-expansion$ of x is described by the T-invariant absolutely continuous measure ${\mu}_{\beta}$. In this paper, we show the mod M normality of the sequence $\{{\in}_n(x)\}$.

• 대한수학회보
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• 제56권2호
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• pp.407-418
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• 2019

In this paper, we study conformal transformations between special class of Finsler metrics named C-reducible metrics. This class includes Randers metrics in the form $F={\alpha}+{\beta}$ and Kropina metric in the form $F={\frac{{\alpha}^2}{\beta}}$. We prove that every conformal transformation between locally dually flat Randers metrics must be homothetic and also every conformal transformation between locally dually flat Kropina metrics must be homothetic.

• 한국재료학회지
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• 제13권5호
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• pp.292-296
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• 2003

In an attempt to enhance phase transformation and homogenization of Mn-doped $FeSi_2$, mechanical alloying of elemental powders was applied. Cold pressing and sintering in vacuum were carried out to produce a dense microstructure, and then isothermal annealing was employed to induce a phase transformation to the $\beta$-$FeSi_2$semiconductor. Phase transitions in this alloy system during the process were investigated by using XRD, EDS and SEM. As-milled powders after 100 h of milling were shown to be metastable state. As-sintered iron silicides consisted of untransformed mixture of $\alpha$-$Fe_2$$Si_{5}$and $\varepsilon$-FeSi phases. $\beta$-$FeSi_2$phase transformation was induced by subsequent isothermal annealing at $830^{\circ}C$, and near single phase of $\beta$-$FeSi_2$was obtained after 24 h of annealing. Thermoelectric properties in terms of Seebeck coefficient, and electrical conductivity were evaluated and correlated with phase transformation. Seebeck coefficient electrical resistivity and hardness increased with increasing annealing time due to $\beta$ phase transformation.

• Applied Microscopy
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• 제25권3호
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• pp.90-98
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• 1995

In the Fe-Si system, a mixture of a($Fe_{2}Si_5$) - and ${\epsilon}$(FeSi)-composition powders was sintered and heat-treated subsequently at various temperatures and time to get thermoelectric ${\beta}$-phase($FeSi_2$) compacts. The different transformational sequences depending on the heat treating temperature were found through the investigation into phase transformation and microstructural development. That is, a rapid eutectoid decomposition of ${\alpha}{\to}{\beta}+Si$ occurred together with a accompanying slow reaction between the dispersed Si formed by above decomposition and the preexisted ${\epsilon}$ phase at temperatures below $830^{\circ}C$. The unreacted Si and the micropores formed due to the density change upon the transformation coarsened as heat treating time elapsed. At temperatures above $880^{\circ}C$, however, transformation was proceeded by a peritectoid reaction of ${\alpha}+{\epsilon}{\to}{\beta}$. It took at least 200min. to achieve 90% volume fracion of transformed ${\beta}$ phase, and the growth of micro-pores was also observed in this transformational sequence with prolonged heat treating time.

• 한국재료학회지
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• 제10권9호
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• pp.636-641
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• 2000

Zr-0.86Sn 합금이 $\beta{\rightarrow}\alpha$상변태 특성에 미치는 Fe와 V의 영향을 광학현미경과 투과전자현미경으로 연구하였다. 공냉의 경우에는 V의 첨가량이 증가함에 다라 $\beta{\rightarrow}\alpha+\beta$변태온도가 감소하여 미세한 $\alpha$-lath들의 폭을 더욱 감소시켰으나, Fe의 경우에는 첨가량이 증가함에 다라 오히려 $\alpha$-lath의 폭이 약간 증가하였다. 수냉의 경우에는 모든 합금에서 martensite 미세구조를 보였다. 수냉한 Zr-0.8Sn, Zr-0.8Sn-0.1Fe, Zr-0.8Sn-0.2Fe, Zr-0.8Sn-0.4Fe, Zr-0.8Sn-0.1V 그리고 Zr-0.8Sn-0.2V 합금에서는 주로 slipped martensite 미세구조가 형성된 반면에 수냉한 Zr-0.8Sn-0.4V 합금에서는 twinned martensite 미세구조가 관찰하였다. 수냉한 Zr-0.8Sn 합금에서 V의 첨가향이 증가함에 따라 slipped martensite에서 twinned martensite 미세구조로의 천이는 M(sub)s 온도의 감소에 기인한 것으로 생각된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1433-1435
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• 2001

The mechanical and phase transformation of the cold isostatically pressed $\beta$-SiC ceramic were investigated as a function of the sintering temperature. The result of phase analysis revealed 6H, 4H, 3C and phase transformation between 3C and 4H showed over 2000$^{\circ}C$ and the $\beta$ ${\rightarrow}$ $\alpha$ phase transformation was in saturation at 2200$^{\circ}C$. The relative density and the mechanical properties of $\alpha$-SiC ceramic was increased with increased sintering temperature. The flexural strength showed the highest value of 230 MPa at 2200$^{\circ}C$. This reason is because crack was propagated through surface flaw. The fracture toughness showed the highest value of 4.2 $MPa{\cdot}m^{1/2}$ at 2200$^{\circ}C$.

• 원예과학기술지
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• 제18권6호
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• pp.797-801
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• 2000

본 연구는 고추에서 Agrobacterium tumefaciens를 이용한 형질 전환시 형질전환율을 높이기 위하여 A. tumefaciens와의 접종시간과 인위적인 상처처리에 따른 효과를 조사하였던 바 고추 형질전환시 자엽절편체의 재분화는 인위적 상처처리 및 A. tumefaciens 접종시간에 의해 영향을 받았다. 접종시간을 3600초로 한 경우의 재분화는 상처처리에 의해 급격히 감소하였으며 자엽 절편체에 대한 인위적인 상처처리가 20초 또는 120초간의 접종시간처리와 병행됨으로써 형질 전환율을 58-72% 이상으로 높이는 효과를 보였다. 형질전환여부의 확인을 ${\beta}$-glucuronidase 염색법과 npt II primer를 이용한 polymerase chain reaction 분석에 의해 수행 한 바 효과적인 것으로 판단되었다.

• Mycobiology
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• 제31권1호
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• pp.42-45
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• 2003

For transformation of Pleurotus ostreatus, two novel vectors, pPhKM1 and pPhKM2, were constructed, using the regulatory sequences of the P. sajor-caju $\beta$-tubulin gene(TUB1) and the ble gene encoding phleomycin binding protein. pPhKM1 contains ble fused to the TUB1 promoter and the Schizophyllum commune GPD terminator. pPhKM2 contains ble fused to the promoter and terminator regions of P. sajor-caju TUB1. To confirm phleomycin-resistance activity, each vector was cotrans-formed with pTRura3-2 into the P. ostreatus homokaryotic $ura^-$ strain. The transforming DNA was stably integrated into the genomic DNA. Subsequently, phleomycin resistance was conferred on wild-type dikaryotic P. ostreatus by transformation with pPhKM1 or pPhKM2. This transformation system generated stable phleomycin-resistant transformants.

• 대한수학회보
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• 제55권4호
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• pp.1231-1240
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• 2018

In this paper, we characterize the conformal transformations between two almost regular (${\alpha},{\beta}$)-metrics. Suppose that F is a non-Riemannian (${\alpha},{\beta}$)-metric and is conformally related to ${\widetilde{F}}$, that is, ${\widetilde{F}}=e^{{\kappa}(x)}F$, where ${\kappa}:={\kappa}(x)$ is a scalar function on the manifold. We obtain the necessary and sufficient conditions of the conformal transformation between F and ${\widetilde{F}}$ preserving the mean Landsberg curvature. Further, when both F and ${\widetilde{F}}$ are regular, the conformal transformation between F and ${\widetilde{F}}$ preserving the mean Landsberg curvature must be a homothety.

• Natural Product Sciences
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• 제14권4호
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• pp.269-273
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• 2008

Microbial transformation of isoxanthohumol (1), a prenylated flavanone from hops, has resulted in the production of a pair of glucosylated derivatives. The structures of these compounds were elucidated to be (2S)-5-methoxy-8-prenylnaringenin 7-O-${\beta}$-D-glucopyranoside (2) and (2R)-5-methoxy-8-prenylnaringenin 7-O-${\beta}$-Dglucopyranoside (3) based on the spectroscopic analyses.