• Economic and Environmental Geology
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• v.51 no.6
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• pp.509-520
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• 2018

Alkalinity is one of the basic variables, which determine geochemical characteristics of natural waters and participate in processes changing concentrations of various contaminants either directly or indirectly. However, not a few laboratories and researchers of Korea still use alkalinity-measurement methods not appropriate for groundwaters, and which becomes one of the major reasons for the poor ion balance errors of the geochemical analysis. This study was performed to review alkalinity-measurement methods, to discuss their advantages and disadvantages, and, thus, to help researchers and analytical specialists in analyzing alkalinity of groundwaters. The pH-titration-curve-inflection-point (PTC-IP) methods, which finds the alkalinity end point from the inflection point of the pH titration curve are revealed to be most accurate. Gran titration technique among them are likely to be most appropriate for accurate estimation of titrant volume to the end point. In contrast, other titration methods such as pH indicator method and pre-selected pH method, which are still commonly being used, are likely to cause erroneous results especially for groundwaters of low ionic strength and alkalinity.

• The Journal of Korean Philosophical History
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• no.30
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• pp.191-225
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• 2010

This paper is the outcome of attempting to approach for reading the Analects of Confucius through the polysemy of Chinese character and indecidability of articles. For this purpose at first, I explained which this Chinese character can be applied for 'philosophy language'. In the 16th century Matteo Ricci had tried to find out the possibility of ideographic script as standing for a universal language. On the other hand, Hegel and Heidegger strictly insisted on the Chinese character is inappropriate for expressing the logic thought of the human being. The reason was as next; firstly, this character had not the preposition and articles, and secondly the only one word could not indicates the bisemy including the meaning of opposition, lastly this language system expresses and communicates only with the change of word order without inflection. But With some scholar like Cassirer, Saussure and Derrida we can confirm the possibility which will discover the Chinese character for using the logic and reasoning language of from different view. Because in the language system of this Chinese character the connection of words in contexts is more important other than meaning as the individual word, in comparison to the language of the West. The Chinese character hides the original meaning until being what kind of event and thing relationship watch inside with different letters. So to speak, the Chinese character is called as 'language of indecidability'. For these points, even though The Chinese character lacks of preposition, articles, and inflection speech etc. the letter systematic, this language system can play a role for expressing as the philosophic language which manages with the complicated problems of the human being.

• Journal of Korean Society for Quality Management
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• v.23 no.1
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• pp.95-105
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• 1995

The error structure of nonlinearized technological growth models, such as, the Pearl curve, the Gompertz curve and the Wei bull growth curve, has zero mean and a constant variance over time. Transformed models, however, like the linearized Fisher-Pry model. the linearized Gompertz growth curve, and the linearized Weibull growth curve have increasing variance from t = 0 to the inflection point.

• Journal of the Korean Society of Combustion
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• v.2 no.1
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• pp.9-16
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• 1997

This paper investigates the linear stability of wakes with special emphasis on the difference of velocity and density. Velocity and density profiles for laminar flows have gaussian profiles. Incompressible wakes have two generalized inflection points and two unstable modes-sinuous and varicose modes. Sinuous modes are more unstable than varicose modes irrespective of density variation, which shows wakes will be destabilized by sinuous modes. Large velocity difference and density difference leads to more unstable wakes due to large momentum difference.

• The Pure and Applied Mathematics
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• v.23 no.3
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• pp.309-317
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• 2016

As a generalization of an inflection point, we consider a point P on a smooth plane curve C of degree m at which another curve C' of degree n meets C with high intersection multiplicity. Especially, we deal with the existence of two curves of degree m and n meeting at the unique point.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.29-32
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• 2004

Purpose of this study is to maximize inflection of code DGPS for LBS. Compare calibration method with pseudo range revision method for this and decides revision method. Also, examine variation that occur by inconsistency of satellite association of user and standard department for problem solution by satellite association. Model revision information through AR model who use RLSLF and minimises satellite association problem. I wish to do optimized code DGPS of digital map so that is possible through an experiment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.216-217
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• 2007

In this paper we investigated the volume resistivity and AC conduction current according to the temperature and voltage. As a result, the volume resistivity comes to be small according to the measurement temperature and voltage. AC conduction current of the heat treatment specimen is increased because of the decrease of insulation.

• The Pure and Applied Mathematics
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• v.28 no.4
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• pp.399-411
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• 2021

We consider a Weierstrass semigroup at a generalized flex on a smooth plane curve. We find the candidates of a Weierstrass semigroup at a 2-flex of higher multiplicity on a smooth plane curve of degree d ≥ 5, and give some examples to show the existence of them.

• Fire Science and Engineering
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• v.22 no.3
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• pp.234-238
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• 2008

Autoignition suppression of hydrogen/air premixed mixtures by $CF_3CHFCF_3(HFP)$ was investigated computationally. Numerical simulation was performed in isobaric and homogeneous system to evaluate the induction times. The detailed chemistry of 93 species and 817 reaction mechanism was introduced for hydrogen/air/HFP mixtures. The result of pure hydrogen/air mixture show that the resulting value of induction time depends relatively weakly on the definition used event though there are various criteria for defining the induction time such as the inflection of temperature, OH and $O_2$ concentrations generally. Also, the autoignition temperature of $H_2/air$ mixture is estimated to about 850K, which is corresponds to the literature value. In the case of HFP addition in $H_2/air$ mixture, the results shows that there are several inflection points of radical concentration, and hence it might be to use the temperature for defining ignition delay. When HFP is added to stoichiometric $H_2/air$ mixture, the effect of ignition delay is outstanding above 10% HFP concentration. As HFP concentration increases, both dilution and chemical effects contribute to delay the ignition. Also, the chemical effect on the ignition delay is more considerable with the higher HFP concentration.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.8
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• pp.743-752
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• 2013

This is the second paper on the combustion characteristics of landfill gas in a constant volume combustion chamber for a large displacement volume commercial engine, and it discusses the combustion process on the basis of pressure measurements. The results show that the bimodal peak pressure phenomenon, which is caused by the interaction of the heat release and the heat transfer, is more apparent as the mixtures are more favorable to combustion, and the magnitudes of the pressures depend on the unburned fraction. In addition, there exist four main inflection points during heat release owing to variations in the heat transfer area related to flame propagation from the ignition point. Furthermore, the number of inflection points increases as the mixture quality worsens because of the extended burn duration. Consequently, the sophisticated interactions between the heat transfer area changing pattern due to flame propagation and transfer duration might cause very peculiar heat release patterns.