• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.790-794
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• 2008

Nucleophilic addition reaction of benzenethiols (PhSH) to 1-(2-nitrovinyl) benzenes ($\beta$ NS) in the presence of triethylamine (TEA) has been studied in acetonitrile at 25 ${^{\circ}C}$. The rate is first order with respect to [PhSH], [TEA] and [$\beta$ NS]. The reaction is found to proceed with the formation of ion-pair between benzenethiol and TEA. A suitable mechanism with the formation of an adduct between ion-pair and substrate in a slow step followed by its rearrangement to 1,2-addition product in a fast step has been proposed and corresponding rate law derived. From the rate law, the rate constants for the interaction between ion-pair and $\beta$NS have been evaluated. Interestingly, in both para-substituted substrates and benzenethiols the rate increases with the electron-withdrawing power of the substituents. The positive sign of $\rho_x$ in benzenethiols has been explained. The magnitude of cross-interaction constant, $\rho_{xy}$ is small (0.08). The magnitude of the Hammett $\rho_x$ values is higher than that of the Bronsted, $\beta_x$ values for benzenethiols. The kinetic isotope effect, $k_H/k_D$, is found to be greater than unity. A suitable transition state with simultaneous formation of $C_\beta$ -H and $B_\alpha$ -S bonds involving the ion-pair and $\beta$NS in a single concerted step has been proposed to account for these observations.

• Korean Journal of Construction Engineering and Management
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• v.15 no.4
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• pp.3-10
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• 2014

As the income level of a country gets improved, people's social, economic, and cultural expectation will grow at the same time. Although the income level of Korea has been remarkably improved, her work-related fatality rate is the highest among OECD countries. Moreover, the rate hasn't been reduced for more than 10 years. This study aims to provide appropriate measures for work-related fatality reduction by comparing the income levels and the work-related fatality rates of countries and by analysing the problems of our worker-oriented accident prevention policy. For the comparison of income level and work-related fatalities, this study suggests income-level incorporated fatality rate, and it turned out that the rate of Korea is the highest among the countries. In order to find out the causes of that result, this study has found that our law enforcement is much weaker than that of UK, which implicates more strict law enforcement policy is needed to improve our work-related safety.

• Communications of the Korean Mathematical Society
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• v.18 no.2
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• pp.375-383
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• 2003

Under some conditions on an array of rowwise independent random variables, Hu et at. (1998) obtained a complete convergence result for law of large numbers with rate {a$\_$n/, n $\geq$ 1} which is bounded away from zero. We investigate the general situation for rate {a$\_$n/, n $\geq$ 1) under similar conditions.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.12
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• pp.884-893
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• 1988

Adaptive controllers for linear unknown coefficient system, that is corrupted by disturbance, are designed by parameter adaptation model reference adaptive control(MRAC). This design is stemmed from the Lyapunov direct method. To reduce the model following error and to improve the convergence rate of the design, an indirect-suboptimal control law is derived. Proper compensation for the effects of time-varying coefficients and plant disturbance are suggested. In the design procedure no complete identification of unknown coefficients are required.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.3
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• pp.100-105
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• 1984

The optimal Load-Frequency Control law is presented with the performance criterion which includes the changing rate of governor speed. The authors propose two controllers. One is a dynamic controller using the method of state augmentation and the other is a constant gain controller with use of the trace function lemma by Kleinman. For a more practical realization, a reduced-order Luenberger observer is applied in order to identify unmeasurable states and power demand. The control schemees presented here are tested through the model developed by Elgerd, and the usefulness is demonstrated.

• Journal of the Korea Safety Management & Science
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• v.6 no.3
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• pp.15-26
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• 2004

There is much dangerous machine in worksite. These make the rate of accidents increase. Specially, among them, dryness equipment work has the highest rate of accidents. Therefore, it has been managed by safety-health law. It is very important to make a special study of work using the dangerous machine. In press work, it is also important to develop safety system program to improve productivity and work safely In this reaserch. the safety mangement system is built for the work improvement of the Press. I will try new development method about dangerous machine.

• Journal of the Korea Safety Management & Science
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• v.6 no.3
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• pp.27-40
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• 2004

There are much dangerous machine in worksite. These make the rate of accidents increase. Specially, among them, the Press work has the highest rate of accidents. Therefore, it has been managed by Industrial safety-health law. It is very important to make a special study of work using the dangerous machine. In press work, it is also important to develop safety system program to improve productivity and work safely, In this reaserch, the safety management system is built for the work improvement of the Press. This paper showed method about dangerous machine.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.10
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• pp.733-739
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• 1988

Adaptive controllers for linear system whose nominal values of coefficients only are known, that is corrupted by disturbance, are designed by signal synthesis model reference adaptive control (MRAC). This design is stemmed from the Lyapunov direct method. To reduce the model following error and to improve the conrergence rate of the design, an indirect suboptimal control law is de rived using the Hamilton Jacobi Beellman equation. Proper compensaton for the effects of time varying coefficients and plant disturbance are suggested. In the design procedure no complete identification of unknown coefficients are required.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.857-860
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• 2006

In the present study, the method and procedure for analysis of impact damage behavior for concrete under penetration and perforation of projectile is investigated. Conservation law, equation of motion, initial and boundary conditions, and FEM formulation are introduced and derived respectively. Specially, the constitutive equation which rate-dependent damage combined with rate-dependent plasticity within the appropriate framework of theory of thermodynamics is examined. This paper aimed at the review with respect to impact damage models for concrete to develop that model. This paper is a basis research for the development of impact damage model for concrete.

• Bulletin of the Korean Chemical Society
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• v.6 no.2
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• pp.115-118
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• 1985

The oxidation of hydrazobenzene by oxygen in methanol solution is catalysed by Co(3MeOsalen) which is a synthetic oxygen carrier. The products are trans-azobenzene and water. The rate of the reaction has been studied spectrophotometrically and the rate law established. A mechanism involving a ternary complex of catalyst, hydrazobenzene and oxygen has been proposed.