• Analytical Science and Technology
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• v.7 no.3
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• pp.321-327
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• 1994

The mild thermal decomposition of 7, 7-dimethyl-1, 2, 3, 4, 5-pentaphenyl-7-silanorbornadiene with excess methyl alcohol proceeds to give 1-methoxydimethylsilyl-1, 2, 3, 4, 6-pentaphenylcyclohexa-2, 5-diene which is colorless needle crystal. The cophotolysis of the solution of 7-silanorbornadiene in the excess ethyl alcohol proceeds with loss of silylenes to give ethoxydimethylsilane which is insertion reaction product of silylene with O-H bond of ethyl alcohol. According to above results, it is presumed that the mechanism of photochemical decomposition and that of mild thermochemical decomposition of 7-silanorbornadiene are different.

• Journal of the Korean Graphic Arts Communication Society
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• v.13 no.2
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• pp.47-53
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• 1995

Photosensitive resin of azide type is good for resolution and inner solvent, but it is really problem to development of practical use because fanctional groups of polymer has many hydrophilic radicals. By careful attention to this point, this study was investigated synthesis term, photo property and development property of composed photosensitive resin of azida type, it is to this effect. 1) H-NMR spectrum of compared DABCI showed amion redical by $\delta$6.0~6.1ppm to substitude for azide radical by amino radical by $\delta$8.9~9.45ppm, and FT-IR absorption spectra showed the absorption bends at 2100cm. 2)FT-IR absorption spectra of PHS1-DAB, PHS2-DAB, CMM-DAB and CHM-DAB showed azida radical pick to be lost at after irradiation by UV light. 3) According to exposuer change of PHS1-DAB, PHS2-DAB, CMM-DAB and CHM-DAB, absorption maximum value of UV spectrum change was 280nm. 4) to compared relative sensitivity of compared photosensitive resin, PHS2-DAB was the best and to compared insolubility rate of compared photosensitive resin, CMM-DAB was the lower. 5)Solubility if NaOH was the best by 1.0mol/$\ell$ and solubility of developing solution of ethanol to water was it in the ratio of 4 to 1.

• Journal of the Korean Magnetic Resonance Society
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• v.22 no.3
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• pp.71-75
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• 2018

The CRISPR-Cas system is the adaptive immune system in bacteria and archaea against invading phages or foreign plasmids. In the type II CRISPR-Cas system, an endonuclease Cas9 cleaves DNA targets of phages as directed by guide RNA comprising crRNA and tracrRNA. To avoid targeting and destruction by Cas9, phages employ anti-CRISPR (Acr) proteins that act against host bacterial immunity by inactivating the CRISPR-Cas system. Here we report the backbone $^1H$, $^{15}N$, and $^{13}C$ resonance assignments of AcrIIA4 that inhibits endonuclease activity of type II-A Listeria monocytogenes Cas9 and also Streptococcus pyogenesis Cas9 using triple resonance nuclear magnetic resonance spectroscopy. The secondary structures of AcrIIA4 predicted by the backbone chemical shifts show an ${\alpha}{\beta}{\beta}{\beta}{\alpha}{\alpha}$ fold, which is used to determine the solution structure.

• Journal of the Korean Applied Science and Technology
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• v.17 no.3
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• pp.149-157
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• 2000

The synthesis of N-methyl glucamine was performed in two step reaction. The first step involves the amination between methylamine and glucose in methane. The N-methyl glucamine was obtained by the reduction of using Ni catalyst under the high pressure. The second step was glucamide anionic derivatives synthesis from N-methyl glucamine, maleic anhydride, lauryl alcohol and laurylamine by Schotten Banmann reaction respectively. Their molecular structures of N-methyl glucamine and glucamide (EG-MAS and AC-MAS) were investigated by IR and $^{1}H-NMR$. Basic physical properties and biodegradability of there glucamide anionic surfactant was investigated. The range of cmc values determined by measurements of surface tention was $10^{-5}{\sim}10^{-4}mol/l$ and the surface tension of the aqueous solution revealed in the range $28{\sim}30$ dyne/cm and their biodegradability was very good in the pH $5{\sim}10$.

• Journal of the Korean Magnetic Resonance Society
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• v.2 no.2
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• pp.85-105
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• 1998

Prions cause neurodegenerative diseases in animals and humans. The scrapie prion protein (PrPSc) is the major-possibly only-component of the infectious prion and is generated from the cellular isoform (PrPC) by a conformational change. Limited proteolysis of PrPSc produces an polypeptide comprised primarily of residues 90 to 231, which retains infectivity. The three-dimensional structure of rPrP(90-231), a recombinant protein resembling PrPC with the Syrian hamster (SHa) sequence, was solved using multidimensional NMR. Low-resolution structures of rPrP(90-231), synthetic peptides up to 56 residues, a longer (29-231, full-length) protein with SHa sequence, and a short here further structure refinement of rPrP(90-231) and dynamic features of the protein. Consideration of these features in the context of published data suggests regions of conformational heterogeneity, structural elements involved in the PrPC\longrightarrowPrPSc transformation, and possible structural features related to a species barrier to transmission of prion diseases.

• Macromolecular Research
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• v.10 no.2
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• pp.115-121
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• 2002

Synthesis of polymers with controlled thermosensitive properties was carried out by conventional radical copolymerization of N-isopropylacrylamide (NIPAAm) with N-vinylpyrrolidone (NVP) taken as a hydrophilic comonomer. Lower activity of NVP rather than NIPAAm was revealed by gravimetric and $^1$H NMR analysis. Thermosensitive properties of the copolymers were investigated. It was found that aqueous solutions of the copolymers undergo thermo-induced phase transition and become opaque, precipitate or gel with heating. After formation of the gels their significant contraction was observed at storage. Swelling degree and amount of expelled water were measured in dependence on the copolymer composition, temperature and ionic strength of environment medium and concentration of the solution. It was determined that in collapsed state gels exhibit quite high water content. According to physico-chemical properties of the copolymers observed they could be suitable for biomedical application as an injectable implant material.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2459-2465
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• 2007

V2O5/TiO2-ZrO2 catalyst modified with V2O5 was prepared by adding Ti(OH)4-Zr(OH)4 powder into an aqueous solution of ammonium metavanadate followed by drying and calcining at high temperatures. The characterization of prepared catalysts was performed using XRD, DSC, solid-state 51V NMR, and FTIR. In the case of calcination temperature of 500 oC, for the catalysts containing low loading V2O5 below 25 wt % vanadium oxide was in a highly dispersed state, while for catalysts containing high loading V2O5 equal to or above 25 wt % vanadium oxide was well crystallized due to the V2O5 loading exceeding the formation of monolayer on the surface of TiO2-ZrO2. The strong acid sites were formed through the bonding between dispersed V2O5 and TiO2-ZrO2. The larger the dispersed V2O5 amount, the higher both the acidity and catalytic activities for acid catalysis.

• Journal of the Korean Ceramic Society
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• v.55 no.2
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• pp.126-134
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• 2018

Using aqueous solution free radical polymerization with glacial acrylic acid (GAA), maleic anhydride (MA) and sodium methallyl disulfonate (SMADS), a novel linear polycarboxylate dispersant was synthesized for ceramics. Dispersant linear structural characterization was done by FTIR, $^1H$ NMR, HPLC and GPC, and the ratio of monomers was determined using an orthogonal experiment. This research is focused on the effects of polymerization temperature, monomer mole ratios and dosage of initiator on ceramic slurry viscosity with linear polycarboxylate dispersant for ceramic dosage rate of 0.30% (based on dry slurry), all of which were investigated by single factor test. The best polymerization conditions for linear GAA-MA-SMADS are when n(AA) : n(MA) : n(SMADS) equals 3.0 : 1.0 : 0.5, the molecular weight of the polymer is 4600 daltons, the initiator sodium persulfate accounts for 7% of the total mass of polymerized monomers, the polymerization temperature is $90^{\circ}C$ and the reaction time is 2 h. The ceramic body slurry viscosity drops from $820mPa{\cdot}s$ to $46mPa{\cdot}s$ when the concentration of the polycarboxylate dispersant is 0.30%.

• Progress in Superconductivity and Cryogenics
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• v.17 no.2
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• pp.31-35
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• 2015

Mapping is a useful tool in the magnetic field analysis and design. In some specific research area, such as the nuclear magnetic resonance (NMR) or the magnetic resonance imaging (MRI), it is important to map the magnetic field in the interesting space with high accuracy. In this paper, an indirect mapping method in the center volume of an air-core solenoid is presented, based on the solution of the Laplace's equation for the field. Through the mathematical analysis on the mapping calculation, we know that the condition number of the matrix, generated by the measurement points, can greatly affect the error of mapping result. Two different arrangement methods of the measurement points in field mapping are described in this paper: helical cylindrical line (HCL) method and parallel cylindrical line (PCL) method. According to the condition number, the HCL method is recommended to measure the field components using one probe. As a simple example, we mapped the magnetic fields in a MRI main magnet system. Comparing the results in the different methods, it is feasible and convenient to apply the condition number to reduce the error in the field mapping calculation. Finally, some guidelines were presented for the magnetic field mapping in the center volume of the air-core solenoid.

• Carbon letters
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• v.10 no.4
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• pp.325-328
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• 2009

This cycloaddition of [70]fullerene with methyl azidoacetate in benzene under ultrasonic irradiated condition afforded the closed [5,6]-bridged aziridino[70]fullerene derivative, which was unusual product of cycloaddition to the 5,6-junction of fullerene. Its structure was determined by FAB-MS, UV-vis, $^1H-$ and $^{13}C$-NMR spectral data. The closed [5,6]-bridged aziridino[70]fullerene-functionalized gold nanoparticle films were self-assembled using the layer-by-layer method on the reactive of glass slides functionalized with 3-mercaptopropyl trimethoxysilane. The functionalized glass slides were alternately soaked in the solution containing closed the [5,6]-bridged aziridino[70]fullerene and 4-aminothiophenoxide/hexanethiolate-protected gold nanoparticles. The closed [5,6]-bridged aziridino[70]fullerene-functionalized gold nanoparticle films have grown up to 5 layers depending on the immersion time. The self-assembled nanoparticle multilayer films were characterized using UV-vis spectroscopy showed that the surface plasmon band of gold at 527 nm gradually became more evident as successive layers were added to the films.