• Archives of Pharmacal Research
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• v.14 no.4
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• pp.364-369
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• 1991

The synthesis and regioselective reactions of a chiral allyl sulfide. (S)-(+)-(1-methylpyrrolidin-2-yl)methyl allyl sulfide (MAS, 1) are described. Remarkable ${\alpha}-regioselectivity$ was observed in the alkylation of the carbanion of MAS while 1:3 mixtures of ${\alpha}-and\;{\gamma}-adducts$ were produced in the addition of the MAS anion to aldehydes. However, a dramatic change of the regioselectivity was witnessed when Lewis acids such as $Et_3Al$, $Et_3B$, and $Ti(O^iPr)_4$ were used as additives in the addition reaction. In these cases, ${\alpha}-adducts$ were formed exclusively. A rationale for the change of regioselectivity is provided. And the stereochemical aspect of the addition reaction is also described.

• The Transactions of the Korea Information Processing Society
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• v.2 no.4
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• pp.554-560
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• 1995

In this paper, we suggest a parallel algorithm to merge priority queues organized in two heaps, kheap and nheap of sizes k and n, correspondingly. Employing max(2$^{-1}$, $\ulcorner$(m＋1)/4$\lrcorner$'s processors, this algorithm requires O(log(n/k)＊log(n)) on an EREW-PRAM, where i is the height of the heap and m is the summation of sizes n and k. Also, when we run it on the MasPar machine, this method achieves a 33.934-fold speedup with 64 processors to merge 8 million data items which consist of two heaps of different sizes. So our parallel algorithm's EPU is close to 1, which is considered as an optimal speedup ratio.eedup ratio.

• Korean Journal of Veterinary Research
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• v.53 no.3
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• pp.169-174
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• 2013

We demonstrated that a mineral aqueous solution (MAS) administered to mice functionally and histologically protected against cisplatin-induced acute renal failure (ARF) and $CCl_4$-induced acute liver failure (ALF). In ARF model, 0.4 and 0.2% MAS decreased mortality and the serum concentrations of blood urea nitrogen (BUN) and creatine in mice. Additionally, 0.4 and 0.2% MAS reduced contraction of distal convoluted tubules and suppressed expression of the proinflammatory cytokines interlukein-6 (IL-6) and tumor necrosis factor (TNF-${\alpha}$) in the kidney. In ALF model, 0.4 and 0.2% MAS decreased serum concentrations of alanine aminotransferase and aspartate aminotransferase in mice. Additionally, 0.4 and 0.2% MAS reduced necrotic areas and suppressed expression of IL-6 and TNF-${\alpha}$ in the liver. These results indicate that a MAS might have protective effects against ARF and ALF.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.2
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• pp.177-185
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• 2001

This study has been carried out to determine localization of Manduca sexta allatotropin (Mas-AT) neuropeptide in developing ventral nerve cord of the silk moth Bombyx mori with polyclonal antisera against Mas-AT. Suboesophageal ganglion (SOG) of the second to fifth instar larvae and 3-day-old pupae showed two to ten Mas-AT-immunoreactive (Mas-AT-IR) cell bodies. There were two to three pairs of labeled cell bodies in each thoracic ganglion (TG) from third instar larvae to adults, with the exception of TG from prepupae. One pair of labeled cell bodies was localized in each abdominal ganglion (AG) 1 to 6 from third instar larvae to 3-day-old pupae, whereas in 5-day-old pupae to adults there was one pair in a similar location of AG 1 to 5. The seventh neuromeres of terminal abdominal ganglia (TAG) from third instar Iarvae to 3- day-old pupae contained four labeled large cell bodies. In each of AG 1 to 7, these cell bodies showed similar allatotropin-immunoreactivity in appearance. Some labeled axons, projected from Mas-AT-lR cells in each of those AG, were extended to the nerves N 1 and N 2.

• The Korean Journal of Quaternary Research
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• v.22 no.2
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• pp.23-27
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• 2008

• Tribology and Lubricants
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• v.39 no.2
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• pp.72-75
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• 2023

Silicon carbide (SiC) is used as a substrate material for power semiconductors; however, SiC chemical mechanical polishing (CMP) requires considerable time owing to its chemical stability and high hardness. Therefore, researchers are attempting to increase the material removal rate (MRR) of SiC CMP using various methods. Mixed-abrasive CMP (MAS CMP) is one method of increasing the material removal efficiency of CMP by mixing two or more particles. The aim of this research is to study the mathematical modeling of the MRR of MAS CMP of SiC with SiO₂ and TiO₂ particles. With a total particle concentration of 32 wt, using 80-nm SiO₂ particles and 25-nm TiO₂ particles maximizes the MRR at 8 wt of the TiO₂ particle concentration. In the case of 5 nm TiO₂ particles, the MRR tends to increase with an increase in TiO₂ concentration. In the case of particle size 10-25 nm TiO₂, as the particle concentration increases, the MRR increases to a certain level and then decreases again. TiO₂ particles of 25 nm or more continuously decreased MRR as the particle concentration increased. In the model proposed in this study, the MRR of MAS CMP of SiC increases linearly with changes in pressure and relative speed, which shows the same result as the Preston's equation. These results can contribute to the future design of MAS; however, the model needs to be verified and improved in future experiments.

• Journal of the Korean Magnetic Resonance Society
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• v.17 no.2
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• pp.86-91
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• 2013

Detailed information about the structural nature of three-coordinate borons in ${\beta}-BaB_2O_4$ is obtained through $^{11}B$ MAS NMR and $^{11}B$ single-crystal NMR. The three-coordinate $BO_3$ of the two borons B(1) and B(2) in ${\beta}-BaB_2O_4$ were distinguished. The spin-lattice relaxation time in the laboratory frame $T_1$ for B(1) and B(2) slowly decreases with increasing temperature, whereas the spin-lattice relaxation time in the rotating frame $T_{1{\rho}}$ for B(1) and B(2), which differs from $T_1$, is nearly constant. The B(1) and B(2) of the two types were distinguished by $^{11}B$ MAS NMR and $^{11}B$ single-crystal NMR.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.380-381
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• 2006

Chemical mechanical polishing (CMP) technology has been widely used for global planarization of multi-level interconnection for ULSI applications. However, the cost of ownership and cost of consumables are relatively high because of expensive slurry. In this paper, we studied the mixed abrasive slurry (MAS). In order to save the costs of slurry, the original silica slurry was diluted by de-ionized water (DIW). And then, $ZrO_2$, $CeO_2$, and $MnO_2$ abrasives were added in the diluted slurry in order to promote the mechanical force of diluted slurry. We have also investigate the possibility of mixed abrasive slurry for the oxide CMP application.

• Journal of the Korean Ceramic Society
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• v.34 no.7
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• pp.781-789
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• 1997

Pressure sintered SiC specimens were joined using MgO-Al2O3-SiO2 (MAS) glass which has a thermal expansion coefficient similar to that of SiC. MAS melt showed excellent behavior of wetting on the SiC substrate over 148$0^{\circ}C$, and the wettability was much influenced by the joining atmosphere. The joining was conducted at 150$0^{\circ}C$ for 30 min in Ar atmosphere. The flexural strength of the joined specimen shows 342~380 MPa up to 80$0^{\circ}C$, which is almost the same as that of as-recieved SiC specimen. However, the flexural strength of the joined specimen decreased to about 80 MPa at 90$0^{\circ}C$ due to softening of the glass melt. The analyses od XRD and WDS show that the reaction between the SiC specimen and the MAS melt produces the oxycarbide glass, which had a high strength and a good stability at high temperatures.

• Journal of the Korean Magnetic Resonance Society
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• v.17 no.1
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• pp.24-29
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• 2013

The structural characteristics of 4-coordinate $BO_4$ [B(1)] and 3-coordinate $BO_3$ [B(2)] groups in $BiB_3O_6$ were studied by $^{11}B$ magic angle spinning (MAS) and single-crystal nuclear magnetic resonance (NMR) spectroscopy. The spin-lattice relaxation time in the laboratory frame, $T_1$, for $^{11}B$ decreased slowly with increasing temperature, whereas the spin-lattice relaxation times in the rotating frame, $T_{1{\rho}}$, for B(1) and B(2), which differed from $T_1$, were nearly constant. Further, $T_{1{\rho}}$ for B(1) and B(2) showed very similar trends, although the $T_{1{\rho}}$ value of B(2) was shorter than that of B(1). The 3-coordinate $BO_3$ and 4-coordinate $BO_4$ were distinguished by $^{11}B$ MAS NMR spectrum and $T_{1{\rho}}$.