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Bang E.Y.,Hanwha Chemical Research and Development Center | Mumm D.R.,University of California at Irvine | Park H.R.,Chonnam National University | Song M.Y.,Chonbuk National University
Ceramics International | Year: 2012

LiNi 1-yCo yO 2 (y = 0.1, 0.3 and 0.5) are synthesized by a solid-state reaction method at 800°C and 850°C from Li 2CO 3, NiO and Co 3O 4 as starting materials. The electrochemical properties of the synthesized LiNi 1-yCo yO 2 are investigated. The synthesized LiNi 1-yCo yO 2 has an α-NaFeO 2 structure with a rhombohedral system (space group; R3̄m). Among all of the prepared LiNi 1-yCo yO 2 (y = 0.1, 0.3 and 0.5) samples, LiNi 0.5Co 0.5O 2 calcined at 800°C for 40 h has the best cycling performance (capacity fading rate 1.4 mAh/g/cycle) and a relatively large first discharge capacity (147.6 mAh/g). LiNi 0.5Co 0.5O 2 calcined at 800°C for 40 h has a large value of I 0 0 3/I 1 0 4. The low degree of displacement of the nickel and lithium ions in this sample is believed to have led to its relatively large first discharge capacity and best cycling performance. © 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Source

Kim J.,Seoul National University | Han J.,Seoul National University | Seo M.,Seoul National University | Kang S.,Seoul National University | And 2 more authors.
Journal of Materials Chemistry A | Year: 2013

A chlorine-assisted method for synthesizing porous boron nitride (BN) is developed. Large scale fabrication is possible by this method under moderate conditions. B and N sources, TiB2 and TiN, respectively, are reacted under a chlorine atmosphere to yield a porous turbostratic BN that displayed a higher surface area (960 m2 g-1) and a larger micropore volume (0.38 cm3 g-1) than have been reported by others. The products exhibit a high hydrogen uptake, as high as 1.01 wt% at 77 K and 1 bar. These results also indicate that the porous BN is a good candidate for testing as a catalyst support and gas sorption material. © The Royal Society of Chemistry 2013. Source

Jang E.R.,Yonsei University | Ryu M.,Ajou University | Park J.E.,Yonsei University | Kim J.-H.,Hanwha Chemical Research and Development Center | And 2 more authors.
Journal of Biological Chemistry | Year: 2010

We screened a protoberberine backbone derivative library for compounds with anti-proliferative effects on p53-defective cancer cells. A compound identified from this small molecule library, cadein1 (cancer-selective death inducer 1), an isoquinolinium derivative, effectively leads to a G2/M delay and caspase-dependent apoptosis in various carcinoma cells with nonfunctional p53. The ability of cadein1 to induce apoptosis in p53-defective colon cancer cells was tightly linked to the presence ofa functionalDNAmismatch repair(MMR)system, which is an important determinant in chemosensitivity. Cadein1 was very effective in MMR+/p53- cells, whereas it was not effective in p53+ cells regardless of theMMRstatus. Consistently, when the function ofMMRwas blocked with short hairpinRNAinSW620 (MMR+/p53 -) cells, cadein1 was no longer effective in inducing apoptosis. Besides, the inhibition of p53 increased the pro-apoptotic effect of cadein1 in HEK293(MMR+/p53+) cells, whereas it did not affect the response to cadein1 in RKO (MMR-/p53+) cells. The apoptotic effects of cadein1 depended on the activation of p38 but not on the activation of Chk2 or other stress-activated kinases in p53-defective cells. Taken together, our results show that cadein1 may have a potential to be an anti-cancer chemotherapeutic agent that is preferentially effective on p53-mutant colon cancer cells with functional MMR. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc. Source

Seo M.S.,Seoul National University | Kim J.H.,Seoul National University | Kim J.M.,Seoul National University | Han J.S.,Seoul National University | And 3 more authors.
Carbon | Year: 2013

Pore structure of carbide-derived carbon (CDC) was tunable by chlorination of Ti(C1-xAx) solid-solution carbides (A = O or N). High-energy ball milling method was used to synthesize various nanocrystalline Ti(C1-xAx) phases. We were able to obtain specific dimension of pore volumes in the range of micropore (<2 nm) or mesopore size (2-50 nm), depending on the compositions of the precursors. The substitutional atoms and their contents effectively modify the characteristics of pores i.e., pore size, volume and their distributions. The micropore volume density, total pore volume density and specific surface area (SSA) of Ti(C0.7O0.3) CDCs were found 1.55 cm 3/g, 1.72 cm3/g and 3100 m2/g, respectively. In contrast, Ti(C0.5N0.5) CDCs showed enhancement of mesopore formation with 3.34 cm3/g, 3.45 cm3/g and 522 m2/g for mesopore volume density, total pore volume density and SSA, respectively. © 2013 Elsevier Ltd. All rights reserved. Source

Kim B.-K.,Chungnam National University | Kim B.-K.,Hanwha Chemical Research and Development Center | Han M.,Chungnam National University
Industrial and Engineering Chemistry Research | Year: 2012

Reactive distillation, which combines reaction and distillation in a single vessel, is receiving increasing attention because of its great potential for use in process intensification. The superposition of reaction and separation in a single processing unit can introduce new patterns of dynamic behavior such as multiplicity and oscillation. Acetic acid was effectively recovered from its dilute aqueous solution in the form of methyl acetate by reactive distillation. The reactive distillation column converting the acetic acid to the methyl acetate was highly nonlinear and showed steady-state multiplicity under certain conditions. The dynamic behavior of the column under multiple steady states was demonstrated to be well explained by nonlinear wave propagation theory. If the maximum conversion was obtained under the condition where the multiplicity appears, then a conventional control scheme could not deal with the control difficulty due to the multiplicity. A profile position control scheme based on wave propagation theory was proposed for the control of the column under multiple steady states, and the performance of the proposed controller was compared with that of conventional controllers. The proposed control scheme using profile positions as controlled variables was shown to give an excellent performance for the control of the reaction conversion and product purity in the reactive distillation. © 2012 American Chemical Society. Source

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