• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.209-214
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• 2003

Numerical simulations are performed at atmospheric pressure in order to understand the effect of additives on flame speed, flame temperature, the radical concentration, the NOx formation in freely propagating $CH_4/O_2/N_2$ flames. The additives used are carbon dioxide and hydrogen chloride which have a combination of physical and chemical behavior on hydrocarbon flame. In the flame established with the same mole of methane and additive, $CO_2$ addition significantly contributes toward the reduction of flame speed and flame temperature by the physical effect, whereas addition of HCl mainly does by the chemical effect. The impact of HCl addition on the decrease of the radical concentration is about 1.6-1.8 times as large as $CO_2$ addition. Hydrogen chloride addition is higher on the reduction of EINO than $CO_2$ addition because of the chemical effect of HCl.

• Journal of Society of Preventive Korean Medicine
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• v.3 no.2
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• pp.91-100
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• 1999

Today, toxicology is used for many purpose, in many fields. Classification of special toxic effect is related next 4 important principles. 1. The chemical substance must move to target organ or tissue that can induce Biological effect. For this movement, we have to understand the physical-chemical characteristic of substance, and the rout of absorption, metabolism, diffusion and excretion of toxic substance. 2. Every biological effect that induced by chemical substance is not harmful. For example, some specific chemical substance is not harmful in liver enzyme system. 3. The strength of biological effect induced by chemical substance is deep related with dose. Nearly all substance is not effective below the specific dose, and it may toxic to death over the specific dose. It is the 'Dose - response relationship' But carcinogen may toxic whether it is law dose or not. 4. The information that was obtained by experimental animal test, could have to adapt in human biology. Because biological effect of chemical substance could be different in every biological species. In past, drugs was obtained by animal or plants. But in the future, it could be obtained by biochemistry, and genome project. Therefore, in Oriental medicine, research and approach is needed at this time, and have to develop new method of experience in toxic method.

• Bulletin of the Korean Chemical Society
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• v.18 no.9
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• pp.911-913
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• 1997

• Bulletin of the Korean Chemical Society
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• v.10 no.6
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• pp.620-621
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• 1989

• Bulletin of the Korean Chemical Society
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• v.11 no.3
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• pp.173-175
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• 1990

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.976-979
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• 2002

This research presents the new method to fabricate small features through applying chemical mechanical micro machining(C3M) for Al5052 and single crystal silicon. To improve machinability of ductile and brittle material, reacted layer was formed on the surface before micro-drilling process by chemical reaction with $HNO_3$(10wt%) and KOH(10wt%). And then workpieces were machined to compare conventional micro-drilling process with newly suggested one. To evaluate whether or not the machinability was improved by the effect of chemical condition, surface defects such as burr, chipping and crack generation were measured. Finally, it is confirmed that C3M is one of the feasible tools for micro machining with the aid of effect of the chemical reaction.

• Journal of applied mathematics & informatics
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• v.41 no.5
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• pp.1085-1102
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• 2023

In this study the magneto hydrodynamic (MHD) micro polar fluid flow of a viscous incompressible fluid past a porous medium in the presence of chemical reaction is considered. This work is devoted to investigate the Soret effect and Electromagnetic radiation effect and analyze analytically. In the energy equation the applied magnetic field strength and in the concentration equation the Soret effect are incorporated. The basic PDE (partial differential equations) are reduced to ODE (ordinary differential equations) using non dimensional variables. Then the analytical solution of the dimensionless equations are found using perturbation technique. The features of the fluid flow parameters are analyzed, discussed and explained graphically. The graphical solutions are found using MATLAB R2019b. Skin friction coefficient at the wall, Couple stress coefficient at the plate and the local surface heat flux are also thoroughly examined. Overall, this study sheds light on the complex interplay between physical parameters in the behavior of MHD micro-polar fluid past a porous medium in the presence of chemical reaction.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.608-612
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• 2016

D-(+)-glucose (Glc) was added to the original Fricke polyvinyl alcohol-glutaraldehyde-xylenol orange (FPGX) hydrogel dosimeter system to make a more stable FPGX hydrogel three-dimensional dosimeter in this paper. Polyvinyl alcohol was used as a substrate, which was combined with Fricke solution. Various concentrations of Glc were tested with linear relevant fitting for optimal hydrogel production conditions. The effects of various formulations on the stability and sensitivity of dosimeters were evaluated. The results indicated that D-(+)-Glc, as a free radical scavenger, had a great effect on stabilizing the dose response related to absorbency and reducing the auto-oxidization of ferrous ions. A careful doping with Glc could slow down the color change of the dosimeter before and after radiation without any effect on the sensitivity of the dosimeter.

• Journal of the Korea Safety Management & Science
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• v.25 no.4
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• pp.25-33
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• 2023

This study analyzed the factors affecting the effectiveness of the Chemical Hazard Risk Management (CHARM). A survey was conducted on 104 learners who participated in the Risk Assessment training course at Occupational Safety and Health Training Institute. Through a self-administered questionnaire, the effect of personal characteristics, corporate characteristics, and safety and health level of the company on the effectiveness of chemical risk assessment was investigated. As a result of statistical analysis, the safety and health level of the company had a positive (+) effect on the effectiveness of Chemical Hazard Risk Management(CHARM), but personal characteristics and corporate characteristics had no relation to it. This study can be used as basic data for further research related to chemical risk assessment in workplaces.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.747-751
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• 2008

The effect of additives in the synthesis of biodiesel fuel using supercritical methanol was studied in order to examine the possibility of application of spent vegetable oil as a raw material, which has high contents of water or free fatty acid. The experiments were performed by varying the contents of water, free fatty acid or antioxidants respectively in a batch reactor. The contents of fatty acid methyl ester was analyzed by a gas chromatography. As the water contents increased, the contents of fatty acid methyl ester decreased, however, the decrease was very little compared with the alkaline and acid catalyst. The effect of the contents of free fatty acid, vitamin E, and ${\beta}$-carotene was negligible.