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Chee Burm Shin,Wonjin Jeon,Jong Ho Kim,곽병규,이종협,Jun Hee Lee,Woon Gi Lee,Sun Woo Lee,Hyeon Soo Park 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.6
The environmental contamination problems caused by accelerated industrialization are becoming increasingly important issues. It is necessary to estimate the distributions of the contaminants and to recognize the risks to our environment. The behavior of volatile organic compounds (VOC) can be analyzed with the concept of fugacity. However, it is difficult to simulate the fate of heavy metals with this concept, because their vapor pressure is extremely small or unknown. Therefore, the aquivalence (from “equivalent aqueous”) theory, which was derived from the fugacity theory, is utilized to establish a mathematical model and to analyze the fate of heavy metals in an urban multimedia system. The target heavy metal is lead and the target region is around Jungrang stream in Seoul. The multimedia is composed of air, water, sediment, soil and vegetation. To verify the proposed mathematical model, the modeling results were compared with the measurement data obtained from the Korea Testing and Research Institute.
Polyvanadate dominant vanadia–alumina composite aerogels prepared by a non-alkoxide sol–gel method
Choi, Jinsoon,Shin, Chee Burm,Suh, Dong Jin Royal Society of Chemistry 2009 Journal of materials chemistry Vol.19 No.41
<P>Vanadia–alumina composite aerogels were synthesized by a cogelation method using alcoholic solutions of metal chlorides under acidic conditions. The resulting aerogels exhibited high surface areas and narrow pore size distributions in the mesoporous region. The vanadium oxides existing on the surface of the aerogels predominantly developed into polyvanadates in terms of chemical structure following the introduction of V species up to 40 wt.% with 500 °C calcination. The intensities of the Raman spectra for the polyvanadates increased with vanadia content, while Raman bands shifted towards lower wavenumbers with decreasing vanadia content due to weak V–O bonds. Homogeneity of the surface vanadates on the aerogels was much higher than that on the impregnated materials, as observed in temperature programmed reduction and NH<SUB>3</SUB> temperature programmed desorption patterns.</P> <P>Graphic Abstract</P><P>Vanadia–alumina composite aerogels were synthesized by a cogelation method using alcoholic solutions of metal chlorides under acidic conditions and subsequent supercritical drying. The vanadium oxides existing on the surface of the aerogels predominantly developed into polyvanadates in terms of chemical structure following the introduction of V species up to 40 wt.% with 500 °C calcination. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b905435a'> </P>
Yi, Jaeshin,Koo, Boram,Shin, Chee Burm,Han, Taeyoung,Park, Seongyong Pergamon Press 2017 Computers & chemical engineering Vol.99 No.-
<P><B>Abstract</B></P> <P>This paper reports a two-dimensional modeling to predict the aging effect on the variation of the electrical and thermal behaviors of a lithium-ion battery (LIB) cell under the constant current (CC) charge and discharge cycling over a long time. To account for the aging effects of the LIB cell due to cycling, the key modeling parameters are expressed as a function of cycling number. In order to validate the modeling methodology introduced in this paper, the modeling results towards the changes of the discharge curves and two-dimensional temperature distributions of the aged LIB cell during CC discharge at different C rates are compared with the experimental measurements after every thousand cycles. The electrical and thermal behaviors predicted by the modeling for the aged LIB cell show good agreement with the experimental data.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Aging effects on the performance of a lithium-ion battery are modeled during cycling. </LI> <LI> Key modeling parameters are expressed as a function of cycle number for aging effects. </LI> <LI> Cycling tests are performed under the constant current charge and discharge cycles. </LI> <LI> Modeling approach is validated by comparing modeling results with experimental data. </LI> <LI> Modeling results for aging effects agree well with cycling test data. </LI> </UL> </P>