• Nuclear Engineering and Technology
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• v.31 no.2
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• pp.157-171
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• 1999

In this work, an automatic software verification method for Nuclear Power Plant (NPP) protection system is developed. This method utilizes Colored Petri Net (CPN) for system modeling and Prototype Verification System (PVS) for mathematical verification. In order to help flow-through from modeling by CPN to mathematical proof by PVS, an information extractor from CPN models has been developed in this work. In order to convert the extracted information to the PVS specification language, a translator also has been developed. ML that is a higher-order functional language programs the information extractor and translator. This combined method has been applied to a protection system function of Wolsong NPP SDS2(Steam Generator Low Level Trip). As a result of this application, we could prove completeness and consistency of the requirement logically. Through this work, in short, an axiom or lemma based-analysis method for CPN models is newly suggested in order to complement CPN analysis methods and a guideline for the use of formal methods is proposed in order to apply them to NPP Software Verification and Validation.

• Explosives and Blasting
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• v.26 no.2
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• pp.1-10
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• 2008

The safe level for residential structures has usually been prescribed as just 'particle velocity' in various specifications in Korea. It implies that there is a possibility of interpreting the 'particle velocity' as the PPV (Peak Particle Velocity), PVS (Peak Vector Sum), or something else, depending on the interpreter. As a result, there have always been some difficulties in both designing a controlled blasting and controling the blast-induced ground vibrations. This paper is intended to show what the role of the safe level criteria such as PPV or PVS is, and also how we should use the concept of the scaled distance equation in a controlled blast design. The paper also emphasizes the importance of the allowable level for various residential structures and its uses in each stage of the controlled blast design.

• Korean Journal of Biological Psychiatry
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• v.6 no.1
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• pp.111-118
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• 1999

Objectives : There have been several evidences that the central nervous system defect is one of the etiologic factors in schizophrenia and high nailfold plexus visibility can reflect these defects indirectly. These are particularly related to the negative symptoms of schizophrenia. In this study, we examined the relationship between nailfold plexus visibility and various clinical variables in schizophrenia. Methods : Forty patients(20 males, 20 females) satisfying the DSM-lV criteria for schizophrenia and forty normal controls(20 males, 20 females) were measured for Plexus Visualization Score (PVS) by using capillary microscopic examination. We used Positive and Negative Syndrome Scale(PANSS), Ulmann-Giovannoni Process-Reactive Questi-onnaire(PRQ), Phillips Premorbid Adjustment Scale(PAS), Continuous Performance Test, and Backward Masking for psychopathology and clinical variables. Results : There was no significant relationship between schizophrenic subjects and normal controls in PVS. PVS was correlated with PANSS positively except negative symptom subscore. PVS was correlated with PRQ score negatively, and with PAS score positively. Conclusions : This study shows high PVS are associated with more severe psychotic symptoms and with clinical variables, such as disease process and premorbid adjustment, in some schizophrenics.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.1
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• pp.31-40
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• 2009

The rheologic properties of elastic impression materials is a very important role as taking high accuracy impression. But, the studies that are focused on the rheologic properties of Korean elastic impression materials are not sufficient. The purpose of this study is to help clinical high accuracy impression taking by testing rheologic properties of elastic impression material that is made by Korea and other countries. Six type III elastic impression materials are tested. Subjects are 2 Korean polyvinylsiloxane(PVS), 2 imported PVS, 1 polyether, and 1 polysulfide. HAAKE RheoStress $1^{(R)}$(Thermo Electron Co. Germany)is used in measuring. HAAKE RheoStress $1^{(R)}$ is plate to plate type rheometer. All subjects is tested 3 times and measuring time is 900 seconds. We measured G′ and loss tangent after mixing. All elastic impression materials had a sigmoid shape on increasing G′ by time and decreasing loss tangent after setting, maximum G' is appeared highest in polyether, and lowest in polysulfide. Initial loss tangent is highest in polyether, and is lowest in Koreans PVS. Significant difference is showed in initial loss tangent between Korean PVS and imported PVS.

• Plant Biotechnology Reports
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• v.2 no.2
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• pp.123-131
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• 2008

Vitrification methods are convenient for cryopreserving plant specimens, as the specimens are plunged directly into liquid nitrogen (LN) from ambient temperatures. However, tissues and species with poor survival are still not uncommon. The development of vitrification solutions with high survival that cover a range of materials is important. We attempted to develop new vitrification solutions using bromegrass cells and found that VSL, comprising 20% (w/v) glycerol, 30% (w/v) ethylene glycol, 5% (w/v) sucrose, 10% (w/v) DMSO and 10 mM $CaCl_2$, gave the highest survival following cryopreservation, as determined by fluorescein diacetate staining. However, the cryopreserved cells showed little regrowth, for unknown reasons. To check its applicability, VSL was used to cryopreserve gentian axillary buds and the performance was compared with those of conventional vitrification solutions. Excised gentian stem segments with axillary buds (shoot apices) were two-step precultured with sucrose to induce osmotic tolerance prior to cryopreservation. Gentian axillary buds cryopreserved using VSL following the appropriate preculturing approach exhibited 78% survival (determined by the regrowth capacity), which was comparable to PVS2 and PVS1 and far better than PVS3. VSL had a wider optimal incubation time (20-45 min) than PVS2 and was more suitable for cryopreserving gentian buds. The optimal duration of the first step of the preculture was 7-11 days, and preculturing with sucrose and glucose gave a much higher survival than fructose and maltose. VSL was able to vitrify during cooling to LN temperatures, as glass transition and devitrification points were detected in the warming profiles from differential scanning calorimetry. VSL and its derivative, VSL+, seem to have the potential to be good alternatives to PVS2 for the cryopreservation of some materials, as exemplified by gentian buds.

• Bulletin of the Korean Chemical Society
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• v.11 no.6
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• pp.552-557
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• 1990

Luminescence quenching reactions of photoexcited tris(2,2'-bipyridine)ruthenium (Ⅱ) complex cation, $Ru(bpy)_3\;^{2+}$, by dialkylviologens (dimethyl, dioctyl, dibenzyl, methyloctyl, methyldodecyl, and methylbenzyl) were studied in sodium dodecylsulfate (SDS), poly(styrenesulfonate) (PSS), and poly(vinylsulfonate) (PVS) solutions. The relative quenching rate varies widely with the microheterogeneous media employed: the highest quenching rate is observed for methyldodecylviologen in homogeneous aqueous medium, dibenzylviologen in SDS and PVS solutions, and dimethylviologen in PSS solution; the lowest rate is found for dimethylviologen in homogeneous medium and SDS solution, methyldodecylviologen in PSS and PVS solutions. These results were interpreted in terms of reduction potential of viologens, affinity of $Ru(bpy)_3\;^{2+}$ and viologens to the microparticles, and the structures of the viologen-colloid complexes.

• Korean Journal of Plant Resources
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• v.33 no.6
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• pp.689-695
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• 2020

This study was conducted to improve and supplement the system of cryopreservation for adventitious bulbs induced by tissue cultured bulb-scales of lily (Lilium spp.) cvs. 'Milky way'. The explants, bulblets and bulb-scale-bulblets, were treated to low temperature (4℃) for 7 days prior to the pre-culture. The adventitious bulbs were pre-cultured in Murashige and Skoog (MS) liquid medium supplemented with sucrose (0.3 and 0.7M). The pre-cultured adventitious bulbs were treated to loading solution (LS1 or LS2, C4 or C6) containing 35% of PVS3 (LS1, C4) or 40% of PVS3 (LS2, C6) for 40 min and exposed to dehydration solution (PVS3, B1) containing 50% glycerol and 50% sucrose for 60 min at 25℃. The adventitious bulbs were moved onto droplets containing 3 µl PVS3 on sterilized aluminum foils, and then soaked into liquid nitrogen (LN) for 60 min. The result of highest regrowth rate as 65.7% was obtained in cold treatment (4℃), osmoprotected with LS1 solution, and cultured in PCM3 medium by using bulb-scale-bulblet for cryopreservation. This result shows that droplet-vitrification could be used as a promising method for long-term storage of lily genetic resource.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.35-35
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• 2021

This study was conducted to improve and supplement the system of cryopreservation for adventitious bulbs induced by tissue cultured bulb-scales of lily (Lilium spp.) cvs. 'MilkyWay'. The explants, bulblets and bulb-scale-bulblets, were treated to low temperature (4℃) for 7 days prior to the pre-culture. The adventitious bulbs were pre-cultured in Murashige and Skoog (MS) liquid medium supplemented with sucrose (0.3 and 0.7M). The pre-cultured adventitious bulbs were treated to loading solution (LS1 or LS2, C4 or C6) containing 35% of PVS3 (LS1, C4) or 40% of PVS3 (LS2, C6) for 40 min and exposed to dehydration solution (PVS3, B1) containing 50% glycerol and 50% sucrose for 60 min at 25℃. The adventitious bulbs were moved onto droplets containing 3 ㎕ PVS3 on sterilized aluminum foils, and then soaked into liquid nitrogen (LN) for 60 min. The result of highest regrowth rate as 65.7% was obtained in cold treatment (4℃), osmoprotected with LS1 solution, and cultured in PCM3 medium by using bulb-scale-bulblet for cryopreservation. This result shows that droplet-vitrification could be used as a promising method for long-term storage of lily genetic resource.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.05a
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• pp.12-12
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• 2010

We developed droplet-vitrification protocol, a combination of droplet-freezing and solution-based vitrification, and applied to germplasm collections of garlic, potato, lily as well as cell lines, including hairy roots, somatic embryos. To establish a garlic cryobank, four Korean garlic field collections at Danyang, Suwon, Mokpo and Namhae were cryopreserved last five years. The protocol applied consisted of preculture for 3-4 days at $10^{\circ}C$ on solid MS medium with 0.3M sucrose, loading for 40 min in liquid medium with 35% PVS3, dehydration with PVS3 for 150 min, cooling in $5{\mu}l$ droplets of PVS3 placed on aluminum foil strips by dipping these strips in liquid nitrogen, warming them by plunging the foil strips into pre-heated($40^{\circ}C$) 0.8M sucrose solution for 30s. A total of over 900 accessions of garlic were stored in liquid nitrogen for long-term conservation using unripe inflorescences, cloves or bulbils. Twelve alternative plant vitrification solutions were designed by modifying cryoprotectant concentrations from the original PVS2 and PVS3. The results suggest that PVS2-based vitrification solutions with increased glycerol and sucrose and/or decreased DMSO and EG concentrations can be applied for medium size explants which are tolerant to chemical toxicity and moderately sensitive to osmotic stress. PVS3 and variants can be used widely when samples are heterogeneous, of large size and/or very sensitive to chemical toxicity and tolerant to osmotic stress.

• Bulletin of the Korean Chemical Society
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• v.6 no.5
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• pp.287-291
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• 1985

The addition of poly(styrenesulfonate) (PSS) to $Ru(bpy)_3^{2+}$ solutions shifted the emission peak by 3 nm to red, and increased emission intensity by 1.8 times. By contrast, poly(vinylsulfonate) (PVS) had little effect on the fluorescence spectrum. The effects of PSS on the spectral properties of $Ru(bpy)_3^{2+}$, were attributed to the presence of a hydrophobic phenyl group in PSS, which interact with $Ru(bpy)_3^{2+}$ by, at least in part, hydrophobic effect. The binding constant of $Ru(bpy)_3^{2+}$ to PSS in 0.1 M NaCl was $6{\times}10^4\;M^{-1}$, and this value was about $10^3$ times higher than those of methyl viologen ($MV^{2+}$) and $Cu^{2+}$. The Stern-Volmer constants of emission quenching of $Ru(bpy)_3^{2+}$ by $MV^{2+}$ and $Cu^{2+}$ in 0.1 M NaCl solutions were 426 and 40 $M^{-1}$, which correspond to second order rate constants($k_q$) of $1.1{\times}10^9\;and\; 1.0{\times}10^8\;M^{-1}s^{-1}$, respectively. The presence of PSS enhanced $K_{SV's}\;by\;{\sim}50$ times, whereas PVS increased the values only 1-4 times. The large enhancing effect of PSS, despite of lower charge density than PVS, was explained in terms of longer life-time of photoexcited $Ru(bpy)_3^{2+}$ bound to PSS and strong association of $Ru(bpy)_3^{2+}$ to PSS due to a specific interaction involving hydrophobic effect. The variation of $K_{SV's}$ on the concentrations of PVS and PSS were also investigated for $Ru(bpy)_3^{2+}-MV^{2+}\;and \;Ru(bpy)_3^{2+}-Cu^{2+}$ photoredox systems.