• Journal of Navigation and Port Research
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• v.41 no.5
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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.

• Journal of the Korean Chemical Society
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• v.19 no.3
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• pp.174-178
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• 1975

The intermediate, 17${\alpha}$-methyl-4-aza-5${\alpha}$-androstan-17${\beta}$-ol(Ⅸ) required for the synthesis of 4-(${\beta}$-guanidinoethyl)-17${\alpha}$-methyl-4-aza-5${\alpha}$-androstan-17${\beta}$-ol(V) was obtained through a reaction of 17${\alpha}$-methyl-3,5-seco-4-norandrostan-17${\beta}$-ol-5-on-3-oic acid(VI) with ammonium hydroxide followed by two reductions(platinum dioxide with hydrogen and lithium aluminium hydride). Condensation of Ⅸ with chloroacetonitrile under anhydrous condition, followed by reduction of the nitrile with lithium aluminium hydride gave 4-(${\beta}$-aminoethyl)-17${\alpha}$-methyl-4-aza-5${\alpha}$-androstan-17${\beta}$-ol(XI). The reaction of XI with 2-methyl-2-thiopseudourea or 3,5-dimethylpyrazole-1-carboxamidine, or cyanamide provided the title compound, V. Relaxation of the nictitating membrane, in the absence of mydriasis, is considered to be evidence of adrenergic neurone blockade. Thus the test compound(V) resembles that of the classical adrenergic neurone blocking agents.

• KSBB Journal
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• v.13 no.2
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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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• v.43 no.5
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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.

• Journal of the Korean Chemical Society
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• v.37 no.2
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• pp.244-248
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• 1993

Nitroalcohols were prepared by a substitution reaction from the corresponding bromoalcohols. The second nitro group was introduced via different methods depending on the carbon chain length. 3,3-Dinitro-1-propanol was obtained by an intramolecular varient of the alkaline nitration method. Whereas 5,5-dinitro-1-pentanol was given by the catalytic oxidative nitration. 3,3-Dinitro-1-propanol and 5,5-dinitro-1-pentanol were converted to 3,3-dinitro-1,6-hexanediol and 4,4-dinitro-1,8-octanediol via Michael reaction with acrolein followed by the reduction of the resulting aldehydes. Acetyl group was a good protecting group for the substitution reaction while THP was for the catalytic oxidative nitration.

• YAKHAK HOEJI
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• v.49 no.6
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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.

• Journal of the Korean Ceramic Society
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• v.28 no.3
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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.

• Korean Journal of Metals and Materials
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• v.49 no.7
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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 $Ti_5Si_3$.

• Korean Journal of Metals and Materials
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• v.50 no.11
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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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• v.24 no.11
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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.