• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1199-1203
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• 2010

Second-order rate constants ($k_N$) have been measured spectrophotometrically for Michael-type reactions of 1-(X-substituted phenyl)-2-propyn-1-ones (2a-f) with a series of alicyclic secondary amines in MeCN at $25.0{\pm}0.1^{\circ}C$. The $k_N$ value increases as the incoming amine becomes more basic and the substituent X changes form an electron-donating group (EDG) to an electron-withdrawing group (EWG). The Br${\o}$nsted-type plots are linear with ${\beta}_{nuc}$ = 0.48 - 0.51. The Hammett plots for the reactions of 2a-f exhibit poor correlations but the corresponding Yukawa-Tsuno plots result in much better linear correlations with ${\rho}$ = 1.57 and r = 0.46 for the reactions with piperidine while ${\rho}$ = 1.72 and r = 0.39 for those with morpholine. The amines employed in this study are less reactive in MeCN than in water for reactions with substrates possessing an EDG, although they are ca. 8 pKa units more basic in the aprotic solvent. This indicates that the transition state (TS) is significantly more destabilized than the ground state (GS) in the aprotic solvent. It has been concluded that the reactions proceed through a stepwise mechanism with a partially charged TS, since such TS would be destabilized in the aprotic solvent due to the electronic repulsion between the negative-dipole end of MeCN and the negative charge of the TS. The fact that primary deuterium kinetic effect is absent supports a stepwise mechanism in which proton transfer occurs after the rate-determining step.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1153-1157
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• 2011

A kinetic study is reported for aminolysis of S-4-nitrophenyl X-substituted thiobenzoates 3a-g in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$. Thiol esters 3a-g are 7.8-47.6 fold more reactive than the corresponding oxygen esters (i.e., 4-nitrophenyl X-substituted benzoates 1a-g). Such reactivity order appears to be in accordance with the expectation that 4-nitrothiophenoxide in 3a-g is a better nucleofuge than 4-nitrophenoxide in 1a-g since the former is 2.64 pKa units less basic than the latter. Hammett plot for the reactions of 3a-g exhibit poor correlation coefficients ($R^2$ = 0.977-0.986) with negative deviation by substrates possessing an electrondonating group (EDG), while the Yukawa-Tsuno plots result in excellent linear correlation ($R^2$ = 0.995-0.997) with ${\rho}$ = 0.93-1.23 and r = 0.57-0.67, indicating that the negative deviation shown by substrates possessing an EDG is caused by ground-state stabilization through resonance interactions but not due to a change in ratedetermining step upon changing the nonleaving-group substituent X. The ${\rho}$ value increases as the incoming amine becomes more basic and more reactive, indicating that the RSP is not operative in the current reactions.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2003.10a
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• pp.183-192
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• 2003

With the availability of complete whole-genomes such as the human, mouse, fugu and chimpanzee chromosome 22, comparative analysis of large genomes from cross-species at varying evolutionary distances is considered one of a powerful approach for identifying coding and functional non-coding sequences. Here we describe a fast and efficient global alignment method especially for large genomic regions over mega bases pair. We used an approach for identifying all similarity regions by HSP (Highest Segment Pair) regions using local alignments and then large syntenic genome based on the both extension of anchors at HSP regions in two species and global conservation map. Using this alignment approach, we examined rearrangement loci in human chromosome 21 and chimpanzee chromosome 22. Finally, we extracted syntenic genome 30 Mb of human chromosome 21 with chimpanzee chromosome 22, and then identified genomic rearrangements (deletions and insertions ranging h size from 0.3 to 200 kb). Our experiment shows that all jnsertion/deletion (indel) events in excess of 300 bp within chimpanzee chromosome 22 and human chromosome 21 alignments in order to identify new insertions that had occurred over the last 7 million years of evolution. Finally we also discussed evolutionary features throughout comparative analyses of Ka/ks (non-synonymous / synonymous substitutions) rate in orthologous 119 genes of chromosome 21 and 53 genes of MHC-I class in human and chimpanzee genome.

• Journal of Korean Elementary Science Education
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• v.33 no.2
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• pp.207-216
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• 2014

Understanding the nature of science (NOS) has been a major component of scientific literacy and an important learning goal in science education (American Association for the Advancement of Science, 1990, 1993; Millar & Osborne, 1998; National Research Council, 1996, 2013). To achieve this goal, it is necessary to include appropriate views of the nature of science in science curriculum such as a textbook. The aim of this study was to conduct a content analysis of the elementary science textbooks to examine the presentation of the nature of science (NOS) using the four themes of scientific literacy, which are (1) nature of scientific knowledge, (2) nature of scientific inquiry, (3) nature of scientific thinking, and (4) nature of interactions among science, technology, and society (STS). Findings show while $3^{rd}$ and $4^{th}$ grade levels of science textbooks heavily emphasize on the Theme I, nature of scientific knowledge and the Theme II, the nature of scientific inquiry, the upper grade levels such as $5^{th}$ and $6^{th}$ grades of science textbooks are well balanced with the four themes of the nature of science. In addition, most of elementary science textbooks little focus on the Theme IV, nature of interactions among science, technology, and society (STS) among the four themes of the nature of science. It might be a shortcoming because the understanding the nature of interacions among science, technology and society (STS) is one of the key components in order for students to be a scientific literate person.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.20-21
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• 2008

Ferroelectric vinylidene fluoride-trifluoroethylene ($VF_2$-TrFE) copolymer films were directly deposited on degenerated Si ($n^+$, 0.002 $\Omega{\cdot}cm$) using by dip coating method. A 1 ~ 3 wt% diluted solution of purified vinylidene fluoride-trifluoroethylene ($VF_2$:TrFE=70:30) in a dimethylformamide (DMF) solvent were prepared and deposited on silicon wafers using dip coating method for 10 seconds. After Post-Annealing in a vacuum ambient at 100~200 $^{\circ}C$ for 60 min, upper aluminum electrodes were deposited by thermal evaporation through the shadow mask to complete the MFS structure. The ferroelectric $\beta$-phase peak of films, depending on the annealing temperature, started to show up around $125^{\circ}C$, and the intensity of the peak increased with increasing annealing temperature. Above $175^{\circ}C$, the peak started to decrease. The C-V characteristics were measured using a Precision LCR meter (HP 4284A) with frequency of 1MHz and a signal amplitude of 20 mV. The leakage-current versus electric-field characteristics was measured by mean of a pA meter/DC voltage source (HP 4140B).

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.1
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• pp.115-123
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• 2001

This paper discussed the assessment of hand of cotton fabrics by enzymatic hydrolysis. The subjective hand and preference of denim fabrics finished by enzymatic hydrolysis were evaluated using the scale developed. The factors affecting consumers taste for denim fabrics were analyzed by the statistical technique. The effects of enzymatic hydrolysis on the properties of cotton fabrics were also evaluated by subjective hand measurements. The results are as follow; As the weight loss increased, evaluators thought that fabrics become finer, smoother, softer, warmer and more refined, and the sense of durability is sleeker and weaker, and the sense of weight is more flexible, flossier, lighter, softer, thinner. They didnt catch the change of moisture related properties according to the rate of weight loss. They also thought fabrics became more elastic, and less wrinklier as the weight loss increased. As the weight loss increased, the fabric was more preferred. The limited weight loss which changes the preference from \"dislike\" to \"like\" was 12.87%. The most preferred fabric was that with 12.87% of weight loss. It is supposed that the preference of fabric was related to the terms such as \"sum-se-ha-da\"(섬세하다), \"mai-ku-rup-da\"(매끄럽다), \"yoo-yon-ha-da\"(유연하다), \"too-bak-ji-an-da\"(투박하지 않다), \"chom-chom-ha-da\"(촘촘하다), \"gil-ki-da\"(질기다), \"kun-juk-goe-ri-ji-an-da\"(끈적거리지 않다), \"ku-kim-i-ka-ji-an-nun-da\"(구김이 가지 않는다).

• Journal of Environmental Health Sciences
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• v.14 no.2
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• pp.1-12
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• 1988

Airborne dust and asbestos fiber concentrations were determined in subway stations located in Seoul area. Two stations, such as Eulchiro 4-Ka Station of Line #2, constructed during a period of 1980-1984 and Hyehwa Station of Line #4, opened in 1985, were selected. The results of the study are as follows. 1. Daily time-weighted average (TWA) concentrations of airborne dusts from 07:00 to 20:00 hours in Line #2 and Line #4 were 0.43$\pm$0.08 mg/m$^3$ and 0.37$\pm$0.12 mg/m$^3$, respectively. Thus, the dust levels in Line #2 were significantly higher than the levels in Line #4 (p < 0.05). 2. Dust levels in the morning (07:00-11:00 hours), noon (11:00-16:00 hours) and in the evening (16:00-20:00 hours) in Line #2 were 0.47$\pm$0.17 mg/m$^3$, 0.37$\pm$0.08 mg/m$^3$, and 0.46$\pm$0.07 mg/m$^3$ respectively. Thus, dust levels in the morning and evening (i.e., during rush hours) were significantly higher than levels in the noon (p < 0.02). However, there was no such difference in dust levels by time in Line #4. 3. Airborne total dust concentrations were well below the occupational health standard of 10 mg/m$^3$, however, the levels were exceeding the ambient air standard recommended by the Korean Environment Administration. 4. All of airborne asbestos fiber concentrations were equal to or below 0.005 fibers/cc. The levels are within both occupational health standards and U.S. EPA criteria. 5. A consideration should be given to the improvements of cleaning methods (such as use of vacuum cleaning instead of brushing) and the existing ventilation (such as more air change and filtration of supply air) for a reduction of dust levels. 6. It is recommended that routine monitoring of airborne dusts and asbestos fibers be conducted because more dusts and asbestos fibers can be produced in the air due to the deterioration of facilities by age and water damage in future.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.77-80
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• 2001

Crystallographic and magnetic characteristics of CoCr-based magnetic thin film for perpendicular magnetic recording media were influenced on preparing conditions. In these, there is that substrate temperature was parameter that increases perpendicular coercivity of CoCrTa magnetic layer using recording layer. While preparation of CoCr-based doublelayer, by optimizing substrate temperature, we expect to increase perpendicular anisotropy of CoCr magnetic layer and prepare ferromagnetic recording layer with a good quality by epitaxial growth. CoCrTa/Si doublelayer showed a good dispersion angle of c-axis orientation $\Delta\theta_{50}$ caused by inserting amorphous Si underlayer which prepared at underlayer substrate temperature 250C. Perpendicular coercivity was constant, in-plane coercivity was controlled a low value about 200Oe. This result implied that Si underlayer could restrain growth of initial layer of CoCrTa thin film, which showed bad magnetic properties effectively without participating magnetization patterns of magnetic layer. In case of CoCrTa/Si that prepared with ultra thin underlayer, crystalline orientation of CoCrTa was improved rather underlayer thickness 1nm, it was expected that amorphous Si layer played a important role in not only underlayer but also seed layer.

• KSBB Journal
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• v.7 no.2
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• pp.92-95
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• 1992

A model for the role of serum was proposed to develop a low serum medium for the large scale cu1ture of mammalian cell. The strategy of medium development adopted in this study facilitated the understanding of the role being carried out by the serum in the culture of hybridoma KAl12 cell line. In this model, the serum components were divided into two main groups : the first group encompasses the nutrient factors that determine the maximum cell density and the second group includes the growth factors that regulate the cell growth rate, The model prediction was compared with the experimental results. The model enabled us to find out several useful aspects of medium composition for cell growth. 1) One particular component in the basal medium became limiting factor when serum concentration level was more than 7%. 2) The growth regulating factors and nutrient factors limited the cell growth at 3% and 5% serum concentration levels respectively.

• Korean Journal of Agricultural Science
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• v.41 no.2
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• pp.101-106
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• 2014

This study was conducted to identify lily species native to Korea from formosan lily (Lilium formosanum) belonging to Longiflorum section. Due to flowering time, flower color and orientation, long shelf life and resistant to diseases, the native lily species can be valuable genetic resources for interspecific hybrids. One of the chloroplast genes, matK, was used to clone and sequence to explore any base changes. The matK was successfully amplified into 1,539 bp (94% of the gene) and phylogenetic tree demonstrated 6 clades for those 11 lily species used in this study. There were one or two base substitutions among 10 lilies native to Korea, while formosan lily native to Taiwan exhibited 6 base substitutions in matK gene, rendering it genetically distant. A restriction enzyme NruI recognized one of the six base changes, and digested the matK gene of 10 native lily species only, but not in formosan lily. The confirmed cleavage characteristic of the target region in matK gene was designed into a CAPS (cleaved amplified polymorphic sequences) marker which will be available to estimate compatibility of interspecific hybridization and to trace the pedigree when those native lilies are crossed with the formosan lily.