• Bulletin of the Korean Mathematical Society
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• v.50 no.5
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• pp.1501-1511
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• 2013

A ring R is called linearly McCoy if whenever linear polynomials $f(x)$, $g(x){\in}R[x]{\backslash}\{0\}$ satisfy $f(x)g(x)=0$, there exist nonzero elements $r,s{\in}R$ such that $f(x)r=sg(x)=0$. In this paper, extension properties of linearly McCoy rings are investigated. We prove that the polynomial ring over a linearly McCoy ring need not be linearly McCoy. It is shown that if there exists the classical right quotient ring Q of a ring R, then R is right linearly McCoy if and only if so is Q. Other basic extensions are also considered.

• Archives of Pharmacal Research
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• v.27 no.9
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• pp.912-914
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• 2004

Seven compounds were isolated from the stem of Acanthopanax senticosus by repeated col-umn chromatography. Their structures were elucidated as isovanillin (1), (-)-sesamin (2), iso-fraxidin (3), (＋)-syringaresinol (4), 5-hydroxymethylfurfural (5), eleutheroside B (6), and eleuth-eroside E (7) by spectral analysis. Among them, isovanillin (1) was isolated for the first time from the family Araliaceae.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.315-319
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• 2010

The near wake of square section cylinders with different corner radii is studied by numerical method to investigate the influence of corner radius. Eight models, R/D=0, 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5 (R is the corner radius and D is the characteristic dimension of the body) at Re=500 were studied. The numerical results of St, CD and CL at R/D=0 and R/D=0.5 were compared with experiments to prove the feasibility and also investigate the trend of flow phenomena by the various radius corners. Results indicate that, as R/D ratio is increased, the Strouha lnumber is increased, the minimum pressure point on the cylinder surface moved own stream. The calculated results shows that between R/D=0.15 to R/D=0.3 have CD and CL.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.5
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• pp.646-652
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• 2009

Experimental results for performance characteristics of HCs refrigerant R-1270 and HCFC refrigerant R-22 during refrigeration system using capillary tube are presented. The system consists of compressor, condenser, capillary tube, evaporator and peripheral devices. Length and diameter of capillary tube are varied for this investigation. The refrigerant mass flow increased as the diameter of capillary tube increased and the length of capillary tube decreased. A refrigeration capacity and compressor work of R-1270 in same length and diameter of capillary tube showed the higher values than those of R-22. A coefficient of performance showed the highest value when the length and diameter of capillary tube are 105 cm and 1.8 mm in this experimental conditions.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.914-917
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• 2002

We have obtained high performance and low voltage driving OCB panel by reducing the critical voltage and retardation matching between liquid crystal layer and compensation films. The critical voltage in the panel has been minimized by flattening color filter layer and optimizing a rubbing process. In addition, an appropriate retardation of the film and LC layer has scanned to achieve low driving voltage and high transmission. The proto-type 17" WXGA OCB panel has demonstrated with less than 5V drive and over 80 degree for all viewing direction except for rubbing direction with over 90% of TN light efficiency.

• The Korean Journal of Applied Statistics
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• v.17 no.1
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• pp.153-164
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• 2004

In this study, we compare multivariate R-techniques in the up-to-date versions of SAS, SPSS, Minitab and S-plus. The direct input method by typing in command is considered for SAS, while the menu-driven method is considered for SPSS, Minitab and S-plus. Comparison was made in terms of input data format, input option, charts and outputs.

• Transactions of Materials Processing
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• v.23 no.5
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• pp.311-316
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• 2014

In the current study, the R-value behavior of a two-layer clad steel was investigated using finite element analysis. Hill's 1948 anisotropic yield equation was employed to characterize the anisotropic behavior of the steel with different assumed properties: isotropic (R=1) and anisotropic (R=2). Experimental R-values were determined by measuring the width and thickness ratios of tensile specimens. Finite element analysis results demonstrate a difference in strain behavior in the width and the thickness directions of the clad steel. The R-value behavior depends on the fraction of the clad materials and total elongation.

• Journal of the Korean Mathematical Society
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• v.46 no.5
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• pp.997-1005
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• 2009

Let R be a prime ring, I a nonzero ideal of R, d a derivation of R and n a fixed positive integer. (i) If (d(x)y+xd(y)+d(y)x+$yd(x))^n$ = xy + yx for all x, y $\in$ I, then R is commutative. (ii) If char R $\neq$ = 2 and (d(x)y + xd(y) + d(y)x + $yd(x))^n$ - (xy + yx) is central for all x, y $\in$ I, then R is commutative. We also examine the case where R is a semiprime ring.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.32-33
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• 1998

생물체에서 유전외적 변형의 하나인 DNA 메틸화는 cis-acting factor의 조성변화를 통하여 세포특이 유전자의 발현과 virus latency, genomic imprinting, mutagenesis등과 같은 생물학적 효과를 나타내는 것으로 알려져 있다.(reviewed by Olle Heby, 1995). 5-azaCR, 5-azaCdR 그리고 6-azaCR의 처리결과는 배아자체의 DNA 메틸화의 유지가 정상발생에 필수적임을 알 수 있으며, 메틸화에 의한 배아발생 조절기작이 존재함을 암시하고 있다. 이러한 과정에서 5-azaCR과 5-azaCdR은 서로다른 경로를 통하여 배아발생에 관여함을 보여주었다. 즉, 5-azaCdR은 주로 DNA에 incorporation되어 작용하는 것으로 여겨지며, 5-azaCR은 DNA 보다는 RNA에 incorporation되어 작용하는 것으로 나타났다. 그리고, 비록 소수의 유전자만이 조사되었지만, 5-azaCdR의 incorporation에 의한 cis-acting factor의 변화는 전사인자인 c-myc proto-oncogene과 fluid 수송에 관여하는 $Na^{+}$, $K^{+}$-ATPase 유전자의 전사를 억제하지 않았다. 반면, 5-azaCR의 RNA로의 incorporation은 전사인자인 c-myc proto-oncogene의 전사를 억제하였으며, 연이어 fluid 수송에 관련되어있는 $Na^{+}$, $K^{+}$-ATPase 유전자의 전사를 억제하였다. 이것은 아마도 RNA로 incorporation된 5-azaCR은 RNA의 post-transcriptional processing에 영향을 주어 trans-acting factor의 조성을 변화, 전사적 repression을 유발한 것으로 사료된다. 생쥐 착상전 초기배아에서 DNA 메틸화는 short-term하게는 cis-acting factor로써 전사적 수준에서 유전자발현 조절하며, 그리고 유전자발현을 통하여 long-term하게는 배아발생에 관여 할 것이라고 사료된다.

• Clinical and Experimental Reproductive Medicine
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• v.15 no.1
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• pp.40-52
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• 1988

Estradiol-17${\beta}$($E_2$) levels in the blood were estimated according to varying the time and amount of the administration of $Clomid^{(R)}$. $Clomid^{(R)}$ were administered on the 2nd, 3rd and 4th menstrual day corresponding to the recruitment period and on the 5th menstrual day corresponding to the selection period of the ovarian follicles, respectively. And $Clomid^{(R)}$ were administered 50 mg, 100 mg and 150 mg/day, repectively. The effects of the sequential HMG to $E_2$ levels in the blood were also estimated. The results were as following : 1. Blood $E_2$ levels according to the day and amount of administration of $Clomid^{(R)}$ were the highest in the group 3(D $2{\sim}6$, 150 mg/day, with HMG) and the lowest in the group 6(D $5{\sim]9$, 50 mg/day, without HMG). $E_2$ levels showed increasing tendency to 0 day. 2. In the cases of the administration of $Clomid^{(R)}$ during the $2nd{\sim}6th$ menstrual day, $E_2$ levels according to the amount were similar among groups and showed increasing tendency daily. 3. In the cases of administration of $Clomid^{(R)}$ during the $2nd{\sim}6th$ menstrual day, $E_2$ levels according to the sequential HMG independent of the amount of $Clomid^{(R)}$ were higher in the with HMG group than without HMG groups. 4. In the case of the administration of $Clomid^{(R)}$ during the $5th{\sim}9th$ menstrual day, $E_2$ levels according to the amount were the highest in the 100 mg/day group and the lowest in the 50mg/day group. 5. In the cases of administration of $Clomid^{(R)}$ independent of the amount during the 5th${\sim}$9th menstrual day, $E_2$ levels according to the sequential HMG were higher in the with HMG group than without HMG group. 6. $E_2$ levels according to the amount independent of the day of the administration of $Clomid^{(R)}$ were the highest in the 100 mg/day group and 150 mg/day, 50 mg/day group in low sequence. 7. $E_2$ levels according to the sequential HMG independent of the day and amount of the administration of $Clomid^{(R)}$ were higher in the with HMG group than the without HMG group. 8. $E_2$ levels according to the day of the administration of $Clomid^{(R)}$ independent of the amount of $Clomid^{(R)}$ and sequential HMG were the highest in the group D 2${\sim}$6 and the lowest in the group D 5${\sim}$9. According to the above results, there were higher $E_2$ levels in the group with sequential HMG than without HMG. Therefore, the hypothesis, postulated initially by the author, was not verified that sequential HMG would not affect the $E_2$ levels which were related to the process of the selection of the ovarian follicle in the connection with 'FSH window'. Because it may be the stimulation after the selection of later predominant follicle. And the highest level of $E_2$ was estimated in the $Clomid^{(R)}$ 150 mg/day group with sequential HMG on the 2nd${\sim}$6th day, and the higher levels were estimated in the 2nd${\sim}$6th day, 3rd${\sim}$7th day and 4th${\sim}$8th day groups than the 5th${\sim}$9th day group. The lower levels were estimated in the $Clomid^{(R)}$ 50 mg/day group without HMG than 100 mg/day and 150 mg/day on the 5th${\sim}$9th day. Therefore, further study will be needed that combines analyses of the E2 levels in the blood according to the various administration of $Clomid^{(R)}$ with or without sequential HMG and determination of the numbers and size of the ovarian follicles by ultrasonogram.