Styryl diphenyl phosphine oxide의 가수분해 반응메카니즘에 관한 연구

신갑철,김학진,이광일 慶尙大學校 1985 論文集 Vol.24 No.1

The rate constants for the hydrolysis of p-substituted styryl diphenyl phosphine oxide(p-H, p-Cl, p-CH_3, p-OCH_3) were determined at various pH and rate equations which can be applied over wide pH range were obtained; below pH 5.0 the rate of hydrolysis of p-substituted styryl diphenyl phosphineoxide were catalyzed by hydronium ion and above pH 8.0, the specific base catalysis were observed. However, in the range of pH 5.0-8.0 the rate of hydrolysis were independent on the pH change andno general base catalysis were observed at pH 4.75. The substituent effects on the hydrolysis of styryl diphenyl phosphine oxide derivatives were also studied. On the basis of these results, the hydrolysis mechanism of p-substituted styryl diphenyl phosphine oxide were proposed.

Phenyl Isocyanides의 가수분해반응 메카니즘과 속도론적 연구

신갑철,성정완,박경곤,전혁제 慶尙大學校 기초과학연구소 1992 基礎科學硏究所報 Vol.8 No.-

Phenyl isocyanaide(PIC) and its derivatives were prepared from the corresponding anilines by the Ugi's method and were identified by the melting point and spectral data. The rate constants for the hydrolysis of PIC and its derivatives (p-Cl, p-Br, m-Cl, p-NO_2) were determined by ultraviolet spectrophotometry at various pH and a following general rate equation which can be applied over a wide pH range were derived. K_t=K_10+K_OH[OH^-] On the bases of this rate equation, general base and substituent effect, identification of final product, and Hammett's plots, plausible mechanisms for the hydrolysis of phenyl isocyanides were proposed.

Malonic acid Benzylidene Diethyl Ester에 대한 Amines의 친핵성 첨가반응에 관한 속도론적 연구

신갑철,정강원 慶尙大學校 1984 論文集 Vol.23 No.2

The kinetic studies on the addition of amines(primary, secondary and tertiary) to Malonic acid Benzylidene Diethyl Ester(MBDE) and Ethylcinnamate(EC) have been carried out in several solvents (MeOH, EtOH and n-PrOH) and at various temperatures. The order of reactivity in solvents was MeOH>eToh>N-PrOH, this result could be explained by the thermodynamic parameters and the dielectric constant of solvents. From the kinetic data, the following reactivity of amines has been derived ; piperidine>n-butylamine>diethylamine>benzylamine. This result was concurred with the Bronsted relationship, expect the deviation of diethylamine which might be resulted from its steric hinderance. It was found that the 3。 amines was less reactive than that of 1。 and 2。 amines toward MBDE. It was therefore suggested that the reactivity of amines was influenced by the formation of intramolecular hydrogen bond. The difference of reactivity between MBDA and EC could be explained by the neighboring group effect.

Kinetics and Mechanism of Alkaline Hydrolysis of [(Methoxy)(p-substituted styryl)-carbene] Pentacarbonyl Chromium(0) Complexes in Aqueous Acetonitrile

Shin, Gap-Cheol,Hwang, Jae-Young,Yang, Ki-Yull,Koo, In-Sun,Lee, Ik-Choon Korean Chemical Society 2005 Bulletin of the Korean Chemical Society Vol.26 No.12

Kinetic studies have been performed for alkaline hydrolysis of a series of [(methoxy)(p-substituted styryl)carbene]pentacarbonyl chromium(0) complexes ($(CO)_5$Cr=$C(OCH_3)CH=CHC_6H_4X$, X = p-$OCH_3$, p-$CH_3$, H, p-Cl, p-$NO_2$). Second-order rate constants $(k_{{OH}^-})$ for the alkaline hydrolysis in 50% acetonitrile-water(v/v) were determined spectrophotometrically at various temperatures. At a low pH region (pH < 7.5), the observed rate constant $(k_{obs})$ remained constant with a small value, while in a high pH region (pH > 9.5), $k_{obs}$ increases linearly with increasing the pH of the medium. The second-order rate constants $(k_{{OH}^-})$ increase as the substituent X changes from a strong electron donating group to a strong electron withdrawing group. The Hammett plot obtained for the alkaline hydrolysis is consisted of two intersecting straight lines. The nonlinear Hammett plot might be interpreted as a change in the rate-determining step. However, the fact that the corresponding Yukawa-Tsuno plot is linear with $\rho$ and r values of 0.71 and 1.14, respectively indicates that the nonlinear Hammett plot is not due to a change in the rate-determing step but is due to ground-state stabilization through resonance interaction. The positive $\rho$ value suggests that nucleophilic attack by $OH^-$ to form a tetrahedral addition intermediate is the rate-determining step. The large negative ${\Delta}S^\neq$ value determined in the present system is consistent with the proposed mechanism.

An Analysis of Factors Relating to Agricultural Machinery Farm-Work Accidents Using Logistic Regression

( Byoung Gap Kim ),( Sung Hyun Yum ),( Yu Yong Kim ),( Namkyu Yun ),( Seung Yeoub Shin ),( Seok Cheol You ) 한국농업기계학회 2014 바이오시스템공학 Vol.39 No.3

Purpose: In order to develop strategies to prevent farm-work accidents relating to agricultural machinery, influential factors were examined in this paper. The effects of these factors were quantified using logistic regression. Methods: Based on the results of a survey on farm-work accidents conducted by the National Academy of Agricultural Science, 21 tentative independent variables were selected. To apply these variables to regression, the presence of multicollinearity was examined by comparing correlation coefficients, checking the statistical significance of the coefficients in a simple linear regression model, and calculating the variance inflation factor. A logistic regression model and determination method of its goodness of fit was defined. Results: Among 21 independent variables, 13 variables were not collinear each other. The results of a logistic regression analysis using these variables showed that the model was significant and acceptable, with deviance of 714.053. Parameter estimation results showed that four variables (age, power tiller ownership, cognizance of the government`s safety policy, and consciousness of safety) were significant. The logistic regression model predicted that the former two increased accident odds by 1.027 and 8.506 times, respectively, while the latter two decreased the odds by 0.243 and 0.545 times, respectively. Conclusions: Prevention strategies against factors causing an accident, such as the age of farmers and the use of a power tiller, are necessary.

친핵성 첨가반응에 대한 용매효과 (I) Phenylvinylketone에 대한 아민의 첨가반응속도에 미치는 용매의 극성효과

신갑철,김태린,Gap-Cheol Shin,Tae-Rin Kim 대한화학회 1992 대한화학회지 Vol.36 No.2

여러 가지 용매에서 phenylvinylketone에 대한 아민(piperidine 및 diethyl-amine)의 친핵성 첨가반응 속도 상수를 $25^{\circ}C$에서 분광광도법으로 측정한 결과 그의 첨가반응 속도상수는 용매의 극성에 비례함을 알았고 이것을 Kirkwood식으로 잘 설명할 수 있었다. 즉, 이 반응은 고리형 구조의 zwitter ion 중간체를 거쳐 일어남을 알 수 있었다. 또 phenylvinylketone에 대한 아민의 첨가반응에서 3차 아민은 1차 및 2차 아민에서 보다 반응이 훨씬 느리게 진행되었으며 이것은 1차 및 2차 아민에서는 고리형 구조의 zwitter ion 중간체를 형성할 수 있고 또한 음전하의 비편재화 및 엔올형의 구조까지 가능하지만 3차 아민에서는 위의 구조들이 불가능하기 때문에 1차 및 2차 아민에서 보다 느리게 진행된다고 생각된다. The rate constants of the nucleophilic addition reaction of amines (piperidine and diethylamine) to phenylvinylketone in various solvents have been determined by UV spectrophotometry at $25^{\circ}C$. On the basis of the high sensitivity of the rate to the polarity of the medium, it may be concluded that the reaction intermediate has zwitterionic character. The effect of the solvents on the rate of the bimolecular nucleophilic addition reaction is described well by the Kirkwood equation: The transition state of the reaction has a cyclic structure formed through an intramolecular hydrogen bond. The addition reaction of primary and secondary amines to phenylvinylketone in all solvents take place considerably faster than that of tertiary amine and this results also can be explained by the intermediate products in the reaction have a cyclic structure formed through an intramolecular hydrogen bond for the primary and secondary amines but not for the tertiary amine.

생체되먹이기를 이용한 두통 환자와 정상인의 근긴장도 비교 : 전두부 근육의 휴식기 기본 측정치 비교 frontalis EMG resting level comparison

임채갑,박장호,이석룡,김경수,신호철,박은숙 대한가정의학회 1992 Korean Journal of Family Medicine Vol.13 No.7

Original Article Journal : Web-based Agricultural Machinery Rental Business Management System

( Seung Yeoub Shin ),( Chang Ho Kang ),( Seok Cheol Yu ),( Byoung Gap Kim ),( Yu Yong Kim ),( Jin Oh Kim ),( Kyou Seung Lee ) 한국농업기계학회 2014 바이오시스템공학 Vol.39 No.4

Purpose: This study was conducted to develop a web-based business management system to ensure the efficient operation and transparent management of government-subsidized agricultural machinery rental businesses. Methods: An MS_SQL2000 database management system (DBMS) solution was utilized in the system for high system compatibility and integrated management. This system was targeted to be compatible with Internet Explorer 6.0 or later and to ensure security and seamless web operations. The system administrator is able to manage a fleet of agricultural machinery, including various inventory codes, release and return, fleet registry, and business performance. Users (farmers) may search the database of rental machinery and reserve them. Results: With respect to rental reservations, the system administrator can manage the fleet by setting the rental status to Approved, Released, or Returned. Through the web, the administrator can also create a database that includes machinery specifications, features, and rental rates. In addition, business performance data can be analyzed using a diverse array of tools to streamline the rental business. Without having to go to the rental office, users can save time and money by searching for and renting agricultural machinery through the information available on the website, including availability, specifications, and rental fees. After deploying the system, the time required to analyze monthly performance and create reports was dramatically reduced from 20 days per person to one day per person. Conclusions: Since 2014, AMRB has been installed and is operating in agricultural machinery rental businesses in 31 cities and counties in South Korea. This study recommends continued expansion and dissemination of AMRB for the systematic and efficient management of agricultural machinery rental businesses.

Satisfaction with the Quality of Agricultural Machinery and the Propensity for Replacement Purchases

( Seung Yeoub Shin ),( Chang Ho Kang ),( Seok Cheol Yu ),( Byoung Gap Kim ),( Yu Yong Kim ),( Jin Oh Kim ) 한국농업기계학회 2014 바이오시스템공학 Vol.39 No.4

This study was conducted to serve as a basis for strengthening policy support and R&D to improve the domestic and international competitiveness of domestic agricultural machinery. Levels of satisfaction among farmers and service engineers were analyzed regarding the current quality of agricultural machinery and the primary consumers` propensity for replacement purchases. Methods: A survey was carried out targeting farmers in over 150 townships and 300 villages in South Korea who collectively used 711 tractors, 286 rice transplanters, and 221 combine harvesters. Furthermore, agricultural machinery service engineers from 20 different after-services were surveyed regarding the quality of main components in domestic agricultural machinery versus those in imported agricultural machinery. Results: The farmers` overall quality satisfaction ratings for tractors, rice transplanters, and combine harvesters ranged from 57.1% to 62.6% in consideration of operating performance, failure rate, and durability. Compared with imports, satisfaction ratings for domestic agricultural machinery were 19.1%p to 38.1%p lower for quality. Regarding engines, transmissions, hydraulics, planters, reapers, threshers, and electrical components, only 5.3% to 25.0% of service engineers indicated that domestic agricultural machinery was higher in quality compared with imports. By contrast, 33.3% to 78.9% of those surveyed indicated that domestic components were lower in quality compared with imports. Intent to purchase replacement agricultural machinery at the end of their respective products` lifecycles was indicated that they planned to purchase imported tractors, rice transplanters, and combine harvesters comprised 25.2%, 46.9%, and 43.9%, respectively. This clearly shows that a very high percentage of farmers were satisfied, particularly for transplanters and combine harvesters. Conclusions: The level of desire for purchasing imported agricultural machinery was very high among those who expressed intent to purchase replacement machinery. Therefore, strong policy support and R&D for domestic agricultural machinery is critical for improving competitiveness on the domestic and foreign markets.

노외기계시스템 분야 : P1-33 ; 농업기계의 위험도 평가방법 선정

김병갑 ( Byoung Gap Kim ),염성현 ( Sung Hyun Yum ),김유용 ( Yu Yong Kim ),윤남규 ( Nam Kyu Yun ),신승엽 ( Seung Yeoub Shin ),유석철 ( Seok Cheol You ) 한국농업기계학회 2015 한국농업기계학회 학술발표논문집 Vol.20 No.1