• Macromolecular Research
• /
• v.15 no.6
• /
• pp.541-546
• /
• 2007

The combination of atom transfer radical polymerization (ATRP) and click chemistry was employed for the efficient preparation of well-defined block copolymers. Bromo terminated poly(methyl acrylate) (pMA-Br) was prepared by an ATRP initiator, ethyl-2-bromoisobutyrate (EBiB). Subsequently, the bromine chain end of pMA-Br was converted to an azide group by simple nucleophilic substitution reaction. ${\alpha}-Alkyn-{\omega}-bromo-functionalized$ polystyrene was also synthesized by ATRP using the alkyn-functionalized initiator, propargyl-2-bromoisobutyrate (PgBiB). In both cases, the conversion was limited to a low level to ensure a high degree of chain end functionality. Then the coupling reaction between the azide end group in $pMA-N_3$ and alkyn-functionalized PgBiB-pSt was performed by Cu(I)catalysis. This coupling reaction was monitored by gel permeation chromatography (GPC). The synthesized block copolymer was characterized by FT-IR, $^1H-NMR$ spectroscopy and $^1H-^1H$ COSY correlation spectroscopy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.05a
• /
• pp.888-889
• /
• 2015

This paper presents a method of constructing the system-on-chip(SoC) based on embedded systems. The proposed method is more compact and effectiveness than former methods. The requirements generation start high level performance simulation and then passes to an executable specification suitable for implementation using a hardware/software co-design tool. The reuse of pre-exiting components is supported, as well as synthesis of the system interface, but only after much work is done to program the hardware/software co-design tool. The actual design flow described allows feedback among all design levels, e.g. from implementation up to requirements, throughout the process. In the future, it is necessary to development the advanced method of constructing system-on-chip based on embedded systems.

• BMB Reports
• /
• v.34 no.6
• /
• pp.502-508
• /
• 2001

A cDNA, encoding the human growth hormone (hGH), was synthesized based on the known 191 amino acid sequence. Its codon usage was optimized for a high level expression in Escherichia coli. Unique restriction sites were incorporated throughout the gene to facilitate mutagenesis in further studies. To minimize an initiation translation problem, a 624-bp cassette that contained a ribosome binding site and a start codon were fused to the hGH-coding sequence that was flanked between the EcoRI and HindIII sites. The whole fragment was synthesized by an overlapped extension of eight long synthetic oligonucleotides. The four-short duplexes of DNA, which were first formed by annealing and filling-in with a Klenow fragment, were assembled to form a complete hGH gene. The hGH was cloned and expressed successfully using a pET17b plasmid that contained the T7 promoter. Recombinant hGH yielded as much as 20% of the total cellular proteins. However, the majority of the protein was in the form of insoluble inclusion bodies. N-terminal amino acid sequencing also showed that the hGH produced in E. coli contained formyl-methionine. This study provides a useful model for synthesis of the gene of interest and production of recombinant proteins in E. coli.

• Korean Journal of Pharmacognosy
• /
• v.35 no.3 s.138
• /
• pp.229-232
• /
• 2004

Chronical intake of alcohol can cause alcoholic fatty liver. Fatty liver is caused by fat infiltration: the state of high rate of fat in liver cells and by losing the balance between the synthesis and the secretion of fatty acid. It could be developed into liver necrosis and cirrhosis. Ka-Mi-Chung-Gan-Tang (KMCGT) is a decoction used for fatty liver as oriental medicines in China. The prescription is composed of Ginseng Radix, Bupleuri Radix, Scutellariae Radix, Pinelliae Tuber, Artemisiae capillaris Herba, Gardeniae Fructus, Zingiberis Rhizoma, Zizyphi Fructus and Glycyrrhizae Radix etc. We have induced alcoholic fatty liver by ethanol administration (6 g/kg, single dose/day, for a week) on rats and observed changes of triglyceride, cholesterol and lipid peroxidation in liver tissues of them. Also we checked the activities of GOT and GPT in blood of rats. KMCGT inhibited significantly the increase of triglyceride, cholesterol, lipid peroxidation level and effectively the increase of malondialdehyde (MDA).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.481-484
• /
• 2007

This paper presents a method of constructing the system-on-chip(SoC) based on embedded systems. The proposed method is more compact and effectiveness than former methods. The requirements generation start high level performance simulation and then passes to an executable specification suitable for implementation using a hardware/software co-design tool. The reuse of pre-exiting components is supported, as well as synthesis of the system interface, but only after much work is done to program the hardware/software co-design tool. The actual design flow described allows feedback among all design levels, e.g. from implementation up to requirements, throughout the process. In the future, it is necessary to development the advanced method of constructing system-on-chip based on embedded systems.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.3A
• /
• pp.318-323
• /
• 2004

In this paper, we present a reducing power consumption of a scheduling for reuse module selection under the time constraint. Traditional high-level synthesis do not allow reuse of complex, realistic datapath component during the task of scheduling. On the other hand, the proposed scheduling of reducing power consumption is able to approach a productivity of the design the low power to reuse which given a library of user-defined datapath component and to share of resource sharing on the switching activity in a shared resource. Also, we are obtainable the optimal the scheduling result in experimental results of our approach various HLS benchmark environment using chaining and multi-cycling in the scheduling techniques.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.40 no.5
• /
• pp.282-287
• /
• 2007

Chloroanilines are aromatic amines used as intermediate products in the synthesis of herbicides, azo-dyes, and pharmaceuticals. 3,4-dichloroaniline (DCA) is the degradation product of some herbicides (diuron, propanil, and linuron) and of trichlorocarbanilide, a chemical used as an active agent in the cosmetic industry. The compound, however, is considered a potential pollutant due to its toxicity and recalcitrant property to humans and other species. With the increasing necessity for bioremediation, we sought to isolate bacteria that degraded 3,4-DCA. A bacterium capable of growth on 3,4-DCA as the sole carbon source was isolated from seaside sediment using a dilution method with a culture enriched in 3,4-DCA. The isolated strain, YM-7 was identified to be Pseudomonas sp. The isolated strain was also able to degrade other chloroaniline compounds. The isolated strain showed a high level of catechol 2,3-dioxygenase activity on exposure to 3,4-DCA, suggesting that this enzyme is an important factor in 3,4-DCA degradation. The activity toward 4-methylcatechol was 53.1% that of catechol, while the activity toward 3-methylcatechol, 4-chlorocatechol and 4,5-chlorocatechol was 18.1, 33.1, and 6.9%, respectively.

• Korean Journal of Materials Research
• /
• v.24 no.7
• /
• pp.339-343
• /
• 2014

$CaWO_4:Sm_x$(x = 0, 0.5, 1.0, 1.5, 2.0 mol%) white phosphors with different concentrations of $Sm^{3+}$ ions were synthesized using the hydrothermal method. The crystal structure, surface, and optical properties of the $CaWO_4:Sm_x$ phosphors were investigated using X-ray diffraction(XRD), field-emission scanning electron microscopy(FE-SEM), photoluminescence(PL) and photoluminescence excitation(PLE). From the XRD results, the crystal structure of the $CaWO_4:Sm$ phosphors was found to be tetragonal. The $CaWO_4:Sm$ phosphors became more cohesive with increasing $Sm^{3+}$-ion concentration. The photoluminescence excitation(PLE) peak of the phosphors, at around 250 nm, was ascribed to the transition from the 1A1 ground-state to the high-vibration level of 1T2 in the $WO{_4}^{2-}$ complex. The maximum emission spectra of the phosphors were observed when the $Sm^{3+}$ concentration was 0.5 mol%. The luminescence intensity of the $CaWO_4$ phosphors was decreased for $Sm^{3+}$ concentrations greater than 0.5 mol%.

• Journal of the Korean Vacuum Society
• /
• v.17 no.6
• /
• pp.566-575
• /
• 2008

We investigated the field emission characteristics from the planar field emitters made of double-walled carbon nanotubes (DWCNTs) synthesized by a catalytic chemical vapor deposition (CCVD) method. Transmission electron microscopy, Thermogravimetric and Raman analysis showed that the carbon materials have a low defect level in their atomic carbon structure, pointing to the synthesis of high-purity DWCNTs. For field emission properties of DWCNTs, the turn-on field of DWCNTs was $1.9\;V/{\mu}m$ and the current density was about $74\;mA/cm^2$ at $8.1\;V/{\mu}m$, which is sufficient for the applications of field emission displays and vacuum microelectronic devices. The DWCNT field emitters also exhibited a uniform field emission pattern and good field emission stability in a diode configuration.

• Journal of Powder Materials
• /
• v.17 no.6
• /
• pp.464-469
• /
• 2010

The Cu nanofluid in ethylene glycol was prepared by electrical explosion of wire, a novel one-step method. The X-ray diffraction, field emission scanning electron microscope and transmission electron microscope were used to study the properties of Cu nanoparticles. The results showed that the nanoparticles were consisted of pure face-centered cubic structure and near spherical shape with average grain size of 65 nm. Ultraviolet-visible spectroscopy (UV-Vis) confirmed Cu nanoparticles with a single absorbance peak of Cu surface plasmon resonance band at 600 nm. The nanofluid was found to be stable due to high positive zeta potential value, +51 mV. The backscattering level of nanofluid in static stationary was decreased about 2% for 5 days. The thermal conductivity measurement showed that Cu-ethylene glycol nanofluid with low concentration of nanoparticles had higher thermal conductivity than based fluid. The enhancement of thermal conductivity of nanofluid at a volume fraction of 0.1% was approximately 5.2%.