• Asian Journal of Atmospheric Environment
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• v.4 no.2
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• pp.80-88
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• 2010

In order to offer a better understanding of air pollution of China as well as East Asia we attempted to characterize the chemical properties of the raw coal materials mined in China and their combusted bottom ashes generated from coal fired power plant. To this end, we measured the chemical characteristics of individual bottom ashes and feed coal fragments collected at a coal fired power generator which was operated with the raw coal dug at a coal mine in China. The chemical properties of these two sample types were determined by a synchrotron radiation X-ray fluorescence (SR-XRF) microprobe method. Through an application of such technique, it was possible to draw the 2D elemental maps in and/or on raw coal fragments and fired bottom ashes. The pulverized fine pieces of feed coal mainly consisted of mineral components such as Fe, Ca, Ti, Ca, and Si, while Fe was detected as overwhelming majority. The elemental mass of combusted bottom ash shows strong enrichment of many elements that exist naturally in coal. There were significant variations in chemical properties of ash-to-ash and fragment-to-fragment. Although we were not able to clearly distinguish As and Pb peaks because of the folding in their X-ray energies, these two elements can be used as tracers of coal fire origin.

• Journal of Korean Society for Quality Management
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• v.23 no.1
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• pp.106-114
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• 1995

The chemical industry has been a leader in the number of registrations for many decades. The big chemical companies in Korea were clearly committed to ISO 9000 and had strong senior management support. However, not many people in the chemical industry are familiar with ISO 9000 and understand how to develop a ISO 9000 quality manual and how to organize a campaign to get the ISO 9000 registration. The purpose of this paper is to briefly summarize the key concerns of chemical companies and how companies can address those concerns and conform to the various elements of the ISO 9000 standards. The case studies of two domestic and foreign companies in establishing ISO 9000 quality system are also discussed.

• Corrosion Science and Technology
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• v.14 no.6
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• pp.273-279
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• 2015

Effects of passive film quality by chemical passivation and solution flow on the corrosion behavior of 304 stainless steel in HCl solution were investigated using a coloration indicator, and by corrosion weight loss, electrochemical polarization and element dissolution measurements. A high redness degree suggests a low passive-film integrity for 304 stainless steel following air exposure, while the minimum redness degree for the samples after chemical passivation suggests a high passive-film integrity. In the static condition, samples subjected to air exposure exhibited a high corrosion rate and preferential dissolution of Fe. Chemical passivation inhibited the corrosion rate due to the intrinsically high structural integrity of the passive film and high concentrations of Cr-rich oxides and hydroxide. Solution flow accelerated corrosion by promoting both the anodic dissolution reaction and the cathodic reaction. Solution flow also altered the preferential dissolution to fast uniform dissolution of metal elements.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.332-335
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• 1995

A simple and effective method for improving Euclidean norm condition number for chemical processing system is presented. The singular value sensitivities of Freudenberg et al. (1982) is used to estimate the behavior of singular values of process transfer function matrix when design parameter is changed, then the condition number can be calculated straightforwardly. The method requires explicit dependencies of each transfer function matrix elements on design parameters. These dependencies can be obtained either by symbolic differentiation in the form of explicit function of design parameters, or by numerical perturbation studies for units with large and complicated models. Gerschgorin-type lower bound for minimum singular value is introduced to detect the large divergencies near singular point due to linearity of sensitivities. The case studies are performed to show the efficiency of the proposed method.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.210-218
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• 2018

Ethylenediaminetetraacetic acid (EDTA)-functionalized KIT-6 and KCC-1 mesoporous silicas were prepared via post-synthesis grafting and examined for their ability to promote the recovery of rare earth metal ions such as $Nd^{3+}$ from an aqueous medium. The obtained adsorption isotherms were fitted to the Langmuir model, which gave a maximum adsorption of $Nd^{3+}$ ions of 109.8 and 96.5 mg/g for KIT-6-EDTA and KCC-1-EDTA, respectively, at $25^{\circ}C$ and pH 6. The adsorption kinetic profile of KIT-6 was faster than KCC-1. KIT-6 was also proved to be more stable against desorption under acidic regeneration conditions.

• Journal of the Korean Chemical Society
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• v.48 no.4
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• pp.414-426
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• 2004

This study analysed inquiry process and activities of the inquiry area in the chemistry field of middle school science textbooks by the inquiry elements based on the 7th science curriculum. The purpose of this study is to grasp a degree of reflecting the 7th science curriculum in the 9th grade science textbooks, and to find out educational implications for the various inquiry learning. Overall, for the analysis of inquiry elements, basic inquiry elements except classification were well reflected on the middle school science textbooks in 9th grade. However, for the integrated inquiry elements, interpreting data occupies almost half of them. This phenomenon is shown in the analysis of inquiry process and inquiry activities, as well. Especially, project and field trip introduced in the 7th science curriculum are hardly found in the textbooks. 9th grade is classified as an upper grade in the 7th science curriculum in terms of inquiry level. Integrated inquiry elements and inquiry activity types, however, are not thoroughly reflected in the 9th grade science textbooks. It is desirable that a variety of inquiry learning of 9th grade be implemented by reconstructing inquiry area based on the results of this study. Hence the degree and ratio of utilizing the integrated inquiry elements and inquiry activity types to the inquiry area of science textbook in 9th grade should be studied.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.633-644
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• 2003

The purpose of this study was to analyze the inquiry elements and inquiry activity of the inquiry area in chemistry I textbooks authorized by 7th curriculum. It was to confirm suitable reflection of the 7th science curriculum and to find educational suggestions of inquiry learning. It was found that the basic inquiry elements except measuring and classifying were well reflected on the textbooks. However, only several integrated inquiry elements and the inquiry activities were well reflected on the same textbooks. For the integrated inquiry elements, interpreting data was shown as the tower above the rest inquiry elements. In the analysis of inquiry activity, the numbers of experiment is placed almost half of all inquiry activities. The sum of two numbers of investigation and discussion is similar ratio to experiment but field trip and project are rarely or low ratio. As the integrated inquiry elements and inquiry activities were not balanced for various inquiry learning. It is suggested that learners be educated with complementary of these aspects in inquiry learning.

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.2105-2108
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• 2011

• Journal of the Korean Chemical Society
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• v.45 no.2
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• pp.183-188
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• 2001

• Journal of the Korean Chemical Society
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• v.48 no.2
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• pp.203-206
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• 2004