• Journal of the Korean Chemical Society
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• v.34 no.5
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• pp.483-489
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• 1990

The rate of hydrolysis of insecticidal 2-chloro-l-(2,4,5-trichlorophenyl)-vinyldimethylphosphate(Gardona) have been investigated in 25${\%}$ aqueous methanol. Studies at varying pH suggest that the hydrolysis of Gardona proceeds through the bimolecular (Ad$_{N-E}$) mechanism involving the transition state and carbanion intermediate as evidenced by solvent effect (m < 0.4, n < 0.7, [m] ${\ll}$ [l](associative SN$_2$ type)), thermodynamic parameters (${\{Delta}S^{\neq}$ = -27∼-32 e.u. & ${\{Delta}H^{\neq}$ = 13∼18 Kcal/mole), hydrolysis rate equation (k = k$_A+_B$ [OH-]), general base catalysis and hydrolysis product analysis, respectively.

• Journal of the Korean Chemical Society
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• v.20 no.3
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• pp.221-228
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• 1976

The kinetics of hydrolysis of hydrazonyl bromides $(p-H,\;p-CH_3,\;p-OCH_3,\;p-Br,\;p-Cl\;&\;p-NO_2)$ have been investigated by UV spectrometry in $60{\%}$ dioxane-water at $25^{\circ}C$ and a rate equation which can be applied over wide pH range was obtained. Below pH2, the rate of hydrolysis of a series of hydrazonyl bromide is accelerated by electrondonating group (${\rho}$ = -0. 94) whereas at the pH values greater than 4, the ${\rho}$-value is 0.54. The rate equation, solvent-, substituent-and bromide ion-effect on the rate of hydrolysis are rationalized in terms of $S_N1$ and $S_N2$ mechanism: below pH 2, the hydrolysis proceed through $S_N2$, however, above pH 4, the hydrolysis is started by the attack of hydroxide ion and in the range pH 2{\sim}$4, these two reactions occur competitively.

• Journal of the Korean Chemical Society
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• v.40 no.12
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• pp.733-740
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• 1996

The rate constants for the hydrolysis of 4'-[N-(9-acridinyl)]-1'-(N-methanesulfonyl)-3'-methoxyquinonediimide(AMQD) were determined by ultraviolet visible spectrophotometer in water at $25^{\circ}C.$ The rate equation which could be applied over wide pH ranges were obtained. On the basis of pH-rate profile, Bronsted plot, hydrolysis product analysis, general base catalysis and substituent effect, the plausible hydrolysis mechanism was proposed: Below pH 3.00, the hydrolysis reaction was proceeded by the attack of water to 4'-position of quinonoid after protonation at nitrogen of acridinyl and between pH 3.00 and 9.00, the addition of water and hydroxide occurred competitively. However, above pH 9.00, the rate constants were dependent upon only the concentration of hydroxide ion.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.48-48
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• 2019

본 연구는 대한민국 매실나무 (207점)와 살구나무 (7점) 열매의 특성평가를 위하여 개체별 과피 및 과육의 착색정도를 조사하였다. 매실나무 열매의 착색상태는 아주 약함이 65점 (31.4%)으로 가장 많았으며, 다음으로 약함 (57점, 27.5%), 아주 짙음 (56점, 27.1%), 중간 (19점, 9.2%), 짙음 (10점, 4.8%)이었다. 살구나무 열매의 착색상태는 아주 짙음이 3점(42.8%)으로 가장 많았고, 다음으로 아주 약함 (2점, 28.6%), 약함과 짙음 (각각 1점, 14.3%)이었다. 매실나무 열매의 착색부위는 적음이 105점 (50.7%)으로 가장 많았으며, 다음으로 중간 (65점, 31.4%), 아주 적음(32점, 15.5%), 많음 (5점, 2.4%)이었다. 살구나무 열매의 착색부위는 아주 많음이 5점 (71.4%)으로 가장 많았고, 다음으로 중간 및 많음 (각각 1점, 14.3%)이었다. 매실나무 과육의 빛깔은 백록색이 103점 (49.8%)으로 가장 많았으며, 다음으로 연등색 (77점, 37.2%), 등색 (25점, 12.0%), 유백색 및 암등색 (각각 1점, 0.5%)이었다. 살구나무 과육의 빛깔은 등색이 4점 (57.1%)으로 가장 많았고, 다음으로 연등색 (2점, 28.6%), 백록색 (1점, 14.3%)이었다.

• Clean Technology
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• v.7 no.2
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• pp.89-97
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• 2001

The purpose of this study was to find the optimum condition of the high removal efficiency of water pollutant as sewage treatment technology using a filtering bed charged with porous sintering-pellet which was planted with hydrophytes. Experiment was carried out by changing concentration of water pollutants(COD, T-N, T-P), kind of hydrophyte, kinds of filtering material and size, and HRT. The result of removal efficiency was obtained as following: COD removal 73.8~87.1% for input concentration range of 50~450mg/L, T-N removal 61.3~77.3% for input concentration range of 7~124mg/L, T-P removal 89.5~99.1% for input concentration ranger of 3~27mg/L. In a comparative experiment of three kinds of hydrophyte(Iris pseudoacorus, Phragmites communis $T_{RIN}$., Oenanthe javanica Dc.), the best removal efficiency of COD and T-N was gained with Iris pse-udoacorus, and Phragmites communis $T_{RIN}$ showed better result than two hydrophytes for the removal efficiency of T-P. In a comparative experiment of four kinds of filtering-materials, the removal efficiencies were in the order of porous sintering-pellet, gravel, nonused-tire and nonused-concrete. It was found that for the porous sintering-pellet, the smaller its diameter, the better its result. In the filtering bed in which was charged with porous sintering-pellets of 5mm diameter and planted with Iris pseudoacorus, the removal efficiency of COD, T-N and T-P were over 80%, 70% and 90% under the concentration of COD 250mg/L, T-N 70mg/L and T-P 15mg/L for 24hrs treatment. Thus, we concluded that a filtering bed charged with porous sintering-pellet and planted with hydrophytes will be suitable for treatment of sewage water as a pro-natural treatment technology.

• Journal of Digital Contents Society
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• v.19 no.6
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• pp.1051-1060
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• 2018

This study aims to propose instituting the serious games of language-based cognitive enhancement for the BIF children. The program consists of 4 cognitive areas (perception, attention, working memory, knowledge inference) in 4 language dimensions (phoneme, word, sentence, discourse). 16 games of 4 areas/2 dimensions with 3 difficulty levels were implemented in a mobile station and pilot-tested to children including BIFs. The results from the pilot tests supported for the validity and effectiveness of our games: Children's game performance correlated with their IQ scores (overall and sub-areas) revealing significant differences between the groups. The stroop scores in pre-and-post training hinted the increase of children's cognitive control.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.1
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• pp.24-30
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• 2006

Three liquid cooling heat exchangers for cooling of telecommunication equipment were designed and their cooling performances were tested. The liquid cooling heat exchangers had twelve rectangular channels $(5\times3 mm)$ with different flow paths of 1, 4, and 12. Silicon rubber heaters were used to provide heat flux to the test section. Heat input was varied from 75 to 400 W, while flow rate and inlet temperature of working fluid were altered from 1.2 to 4.0 liter/fin and from 15 to 3$30^{\circ}C$, respectively. The 4-path heat exchanger showed lower and more uniform average inner temperatures between heaters and the surface of heat exchanger than those of the others. To obtain optimal distribution of working fluid to each channels of liquid cooling heat exchangers, 2-3-2 and 4-3 type tube distributors were designed, and their distribution performances of working fluid were numerically and experimentally investigated. The distributor of the 2-3-2 type showed superior distribution performance compared with those of the 4-3 type distributor.

• Applied Biological Chemistry
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• v.37 no.4
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• pp.287-294
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• 1994

New 3-phenyl-1-(2-furyl)propenones, 1 and 3-phenyl-1-(2-furyl)-3-thiophenyl-propanone, 2 derivatives were synthesized, and their fungicidal activities in vitro against Botrytis cineria (BC), Valsa ceratosperma (VC), Scelerotium cepivorum (SC) and Phytophthora capsici (PC) were investigated using a generalized structure-activity relationship (SAR). The activity of 1 was superior to those of 2, and nonsubstituent, 1a and chloro group substituent, 1d of E (Syn) conformer were the most effective $(EC_{50}=10{\sim}12\;ppm)$ compound to BC. Antifungal activities were able to predict to depend essentially on the ${\beta}$ carbon and their positive charge from the results that the good correlation $(r^2=0.90)$ was observed between hydrolysis rate constant (logk) of 1 and the electronic parameter $({\sigma})$ of X-substituent on the ${\beta}-phenyl$ ring.

• Journal of the Korean Dietetic Association
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• v.20 no.4
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• pp.247-256
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• 2014

This study compared the perception, necessity, and satisfaction of free school foodservice among parents of students with and without access to free school foodservice. The sample included parents of students with access to free school foodservice (FSF group, 250 parents) or paid school foodservice (PSF group, 250 parents) in Taean, Chungnam. With regard to perception of school foodservice, 30% of PSF parents responded that it is a necessary part of school education, whereas 52% of FSF parents considered it as a part of national welfare service; this difference was significant (P<0.001). In terms of positive remarks, most parents in the PSF group highlighted convenience whereas the FSF group answered that their children were penalized; this difference was significant (P<0.001). In addition, 94% of PSF parents and 96.8% of FSF parents indicated that school foodservice is necessary. In terms of the perception of the free school foodservice, more FSF parents (96.4%) than PSF parents (84.4%) answered that they knew free school foodservice well; this difference was significant (P<0.001). With regard to target recipients of the free school foodservice, most parents in the PSF group said that needy students should be selected, whereas the FSF group said that all students should be eligible; this difference was significant (P<0.001). Acceptance of free school foodservice in the FSF group (34.4%) was significantly higher than that in the PSF group (23.2%). Satisfaction with free school foodservice was 3.5 points in the FSF group, which was significantly higher than the 2.9 points in the PSF group (P<0.001). In summary, parents of students with access to free school foodservice showed more positive perception and higher satisfaction than parents of students with paid school foodservice. This study recommends that parents' suggestions be considered and further perception and responses on free school foodservice be investigated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.4
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• pp.195-201
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• 2017

In this study, the viscosity of a $CO_2-gas$ mixture was investigated for the transportation of the captured $CO_2-gas$ in pipelines and for the designing of a thermal system, both of which involve the utilization of the $CO_2-gas$ mixture. The viscosities of the $CO_2-gas$ mixture, $CO_2+CH_4$, $CO_2+H_2S$, and $CO_2+N_2$ were predicted using three different models as follows : Chung, TRAPP, and REFPROP. The predictability values of the models were validated by comparing the estimated results with the experiment data for the $CO_2+CH_4$ and $CO_2+N_2$ under high-density conditions. The Chung model showed 2.41%, which is the lowest mean deviation of the prediction among the model. Based on the Chung model, the mixture mole fractions were changed from 0.9, 0.95, and 0.97, the mixture pressure was ranged from 80 bar to 120 bar by 10 bar, and the mixture temperature was varied from 310 K to 400 K by 10 K to observe the effects of the parameters on the mixture viscosity. Considering the high mole fraction of the $CO_2$ in the mixture, a significant variation of the mixture viscosity was observed close to the pseudo-critical temperature, and the viscosity for the $CO_2+H_2S$ mixture shows the highest values compared with those of the $CO_2+CH_4$ and $CO_2+N_2$.