• 한국항해항만학회지
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• 제41권5호
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• pp.297-302
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• 2017

The tracking filter plays a key role in accurate estimation and prediction of maneuvering the vessel's position and velocity. Different methods are used for tracking. However, the most commonly used method is the Kalman filter and its modifications. The ${\alpha}-{\beta}-{\gamma}$ filter is one of the special cases of the general solution provided by the Kalman filter. It is a third order filter that computes the smoothed estimates of position, velocity, and acceleration for the nth observation, and predicts the next position and velocity. Although found to track a maneuvering target with good accuracy than the constant velocity ${\alpha}-{\beta}$ filter, the ${\alpha}-{\beta}-{\gamma}$ filter does not perform impressively under high maneuvers, such as when the target is undergoing changing accelerations. This study aims to track a highly maneuvering target experiencing jerky motions due to changing accelerations. The ${\alpha}-{\beta}-{\gamma}$ filter is extended to include the fourth state that is, constant jerk to correct the sudden change of acceleration to improve the filter's performance. Results obtained from simulations of the input model of the target dynamics under consideration indicate an improvement in performance of the jerky model, ${\alpha}-{\beta}-{\gamma}-{\eta}$ algorithm as compared to the constant acceleration model, ${\alpha}-{\beta}-{\gamma}$ in terms of error reduction and stability of the filter during target maneuver.

• 대한화학회지
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• 제19권3호
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• pp.174-178
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• 1975

4-(${\beta}$-Guanidinoethyl)-17${\alpha}$-methyl-4-aza-5${\alpha}$-androstan-17${\beta}$-ol(V)을 합성하는데에 필요한 중간화합물인 17${\alpha}$-methyl-4-aza-5${\alpha}$-androstan-17${\beta}$-ol(IX)은 4단계를 거쳐 합성하였으며 IX을 chloroacetonitrile과 축합반응을 한후 $LiAlH_4$로서 환원하여 4-(${\beta}$-aminoethyl)-17${\alpha}$-methyl-4-aza-5${\alpha}$-androstan-17${\beta}$-ol(XI)을 얻었다. Tktle compound인 V은 3가지의 시약, 2-methyl-2-thiopseudourea,3,5-dimethylpyrazole-1-carboxamidine, cyanamide를 각각 XI와 반응시켜 좋은 수득률을 얻었다. 약리작용의 실험결과 V은 classical한 adrenergic neurone blocking agents와 유사하며 혈압강하제로서의 전망은 좋다고 예상된다.

• KSBB Journal
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• 제13권2호
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• pp.133-140
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• 1998

Using rlFN-$\alpha$ and rhGH as the model proteins, the refolding performances of the published processes were evaluated and compared. Key engineering parameters such as the type of denaturant and this concentration, protein concentration in the refolding buffer, and pH and ionic strength of the buffer were experimentally investigated. Furthermore, the role of a co-solvent of surfactant type in aggregation reduction was also studied. Of the denaturants tested (8M urea, 6M guanidine HCI, 0.5% SDS), SDS at alkaline pH (9.5) and ambient temperature gave the highest recovery yield. The SDS process was effective in the refolding of observed where dissolution proceeded better under lower strength (10 mM) but aggregation was suppressed under higher strength (>50 mM.) When PEG-4000 and/or Tween were added as co-solvent or refolding-enhancing additive, 1.6-2 times higher yield was realized. The‘masking’of the hyrophobic patches located on the surface of the protein with the surfactant molecules was believed to be responsible for the considerable reduction in aggregation during refolding.

• BMB Reports
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• 제43권5호
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• pp.369-374
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• 2010

The PC12 is the widely used cell line to study neuronal differentiation. We had extensively investigated the details of protein expression in differentiated PC12 cells by proteomic analysis. The cells were incubated at the presence of nerve growth factor. We had analyzed the expression changes in the differentiating PC12 cells by 2-dimensional electrophoresis and the identification of the proteins using MALDI-TOF MS. By comparing expression pattern in the time course, we identified the candidate genes which are associated with neuronal differentiation. Among these genes, we performed real-time PCR analysis to validate $Idh3{\alpha}$ expression by the time course. To identify the function of $Idh3{\alpha}$ in neuronal differentiation stage, the transfection of $Idh3{\alpha}$ to PC12 cells was performed. As a result, we proved that up-regulation of $Idh3{\alpha}$ causes reduction in neural differentiation of PC12 cells. Based on these data, we suggest that $Idh3{\alpha}$ plays a role to the neuronal differentiation.

• 대한화학회지
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• 제37권2호
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• pp.244-248
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• 1993

니트로 알코올은 브로모 알코올의 치환반응으로 얻었다. 두번째 니트로 원자단은 사슬 길이에 따라 다른 방법으로 도입했다. 3,3-dinitro-1-propanol은 분자내 염기성 니트로화 반응으로 형성되면 5,5-dinitro-1-pentanol은 산화촉매 니트로화 반응으로 얻었다. 3,3-dinitro-1,6-hexanediol과 4,4-dinitro-1,8-octanediol은 3,3-dinitro-1-propanol과 5,5-dinitro-1-pentanol에 acrolein을 가해 Michael 반응으로 알데히드를 얻고 환원하여 합성했다. 치환반응시 알코올 보호기는 아세틸기가 좋으며 산화촉매 니트로 반응에서는 THP 원자단이 좋은 보호기이다.

• 약학회지
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• 제49권6호
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• pp.443-448
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• 2005

Diosgenin (25 (R) - spirost-5-en-3$\beta$ -ol) was oxidized with 2,3-dichloro -5,6-dicyano-1,4-benzoquinone to form 25(R)-1,4,6-spirostatrien-3-one (1) as rigid cyclic $\alpha$,$\beta$-unsaturated carbonyl compound. This compound was reacted with $H_{2}O_{2}$, m-chloroperoxybenzoic acid (mCPBA), NaOCl in the presence with (R,R)- or (S,S)-Jacobsen catalyst, tert-butyl-hydroperoxide (TBHP) in Mo$(CO)_{6}$, and in VO $(acac)_{2}$ catalyst, respectively, 25(R) -1,4,6-spirostatrien -3-one (1) was reduced with $NaBH_{4}$ L-Selectride, $LiAIH_{4}$,$BH_{3}$ $\cdot$$(CH_{3})_{2}S$, Superhydride, Red-Al, and lithium tri-tert-butoxyaluminium hydride. And 25(R)-4,6-spirostadien-3$\beta$-ol (4) was treated with $H_{2}O_{2}$, mCPBA, TBHP in D - (-) - and L-(+)-diisopropyltar-trate and $Ti(OiPr)_{4}$ condition (Sharpless asymmetric epoxidation), TBHP in $Mo(CO)_{6}$, and in $VO(acac)_{2}$ catalyst, respectively.

• 한국세라믹학회지
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• 제28권3호
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• pp.189-196
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• 1991

Si(OC2H5)4, commercial AlN and Y2O3 powder were used as the precusor of Si3N4, AlN, Y2O3, respectively. After Si3N4 powder was synthesized by carbothermal reduction and nitridation at 135$0^{\circ}C$ for 13h in N2 atmosphere, characteristics of synthesized powder and the ceramics sintered at 178$0^{\circ}C$ for 1h under 30MPa were investigated. In order to evaluate the reliability of sintered body, Weibull modulus was investigated. Premixing of carbon black as a reduction agent had no effect on Si(OH)4 formation, and Si3N4 powder synthesized from Si(OC2H5)4 was $\alpha$-Si3N4 single phase. Mechanical properties of sintered body were measured as follows : flexural strength ; 750MPa, fracture toughness ; 3.71Mn/3/2, hardness : 17.4GPa, thermal shock resistence temperature ; $600^{\circ}C$. Flexural strength at room temperature was 750MPa and was retained up to 110$0^{\circ}C$. The Weibull modulus of sintered body was 10.7.

• 대한금속재료학회지
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• 제49권7호
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• pp.577-582
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• 2011

The newly developed ${\alpha}-case$ controlled mold material for Ti investment castings was suggested in this research. The $Al_2O_3$ mold containing interstitial $TiO_2$ and substitutional $Ti_3Al$ was manufactured by the reaction between $Al_2O_3$ and Ti. It is obvious that as the $TiO_2$ and $Ti_3Al$ content in the mold surface were increased, the depth of the interfacial reaction was significantly reduced. In addition, substitutional $Ti_5Si_3$ in the mold surface owing to the reaction between Ti and $SiO_2$ from the binder was effective for ${\alpha}-case$ reduction. Therefore, the ${\alpha}-case$ reduction was accomplished by the diffusion barrier effect of interstitial $TiO_2$, substitutional $Ti_3Al$ and $Ti_5Si_3$.

• 대한금속재료학회지
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• 제50권11호
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• pp.823-828
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• 2012

Direct reduction of $Ta_2O_5$ using liquid calcium was investigated. The experiment was conducted in a closed stainless steel chamber in an Ar atmosphere for 5-120 minutes. Most of $Ta_2O_5$ was reduced to ${\alpha}-Ta$ in 30 minutes above 1173 K and at a molar ratio of Ca and $Ta_2O_5$ above 10. The particles size increased with the reaction temperature, but it did not change much above 1223 K. The oxygen content of metal Ta was about 1 wt%.

• Bulletin of the Korean Chemical Society
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• 제24권11호
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• pp.1664-1670
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• 2003

$NaBH_4$ with catalytic amounts of $MoCl_5$ can readily reduce a variety of carbonyl compounds such as aldehydes, ketones, acyloins, ${\alpha}$-diketones and conjugated enones to their corresponding alcohols in good to excellent yields. Reduction reactions were performed under aprotic condition in $CH_3CN$ at room temperature or reflux. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing system.