• Journal of the Korean Chemical Society
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• v.66 no.4
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• pp.265-268
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• 2022

• Bulletin of the Korean Chemical Society
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• v.31 no.10
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• pp.2786-2790
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• 2010

Three new oleanane-type triterpene saponins (1, 2 and 3) were isolated from aerial parts of Gladiolus gandavensis, along with two known compounds (4 and 5). Their structures were elucidated as 29-O-($\beta$-D-glucopyranosyl)-$2{\beta}$,$3{\beta}$-dihydroxyolean-12-en-28-oicacid(1), 3-O-($\beta$-D-xylopyranosyl)-29-O-($\beta$-D-glucopyranosyl)-12-en-28-oic acid (2), and $2{\beta}$,$3{\beta}$,29-trihydroxyolean-12-en-28-oic acid 28-O-[$\beta$-D-glucopyranosyl($1{\rightarrow}2$)-($\alpha$-L-rhamnopyranosyl($1{\rightarrow}6$))-$\beta$-D-glucopyranosyl] ester (3), by spectroscopic methods, and by comparison with known analogues. These oleanane-type triterpene saponins glycosidated at C-29 were not obtained frequently.

• Advances in environmental research
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• v.8 no.1
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• pp.39-54
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• 2019

This paper presents comprehensive scientific details about mangrove soil in Gulf of Kachchh, Gujarat. A total of ten sites were studied during November, 2011 to December, 2014 in order to know the physico-chemical characteristics of mangrove soil. The results indicated that the soil in GoK had silty loam texture. Other physico-chemical parameters ranged as; pH: 7.39-7.61, Bulk Density: 0.30 g/㎤-0.54 g/㎤, Particle Density: 1.26 g/㎤-1.76 g/㎤, Organic Carbon: 0.70%-1.13%, Organic Matter: 1.01%-1.74% and Moisture Content: 33.45%-56.38%. The paper would be useful to the stakeholders, coastal managers and scientific communities to know the mangrove soil conditions of Gulf of Kachchh for management and planning for conservation of mangrove ecosystem.

• Journal of the Korean Chemical Society
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• v.59 no.1
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• pp.45-53
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• 2015

This research aims to study on educational methods of Nature-Study extracted through a wide body of literatures and meaning of Nature-Study toward today's science education. For this, viewpoints of Nature-Study were drown by previous historical study about Nature-Study. And educational methods of Nature-Study based on viewpoints of Nature-Study were abstracted by collecting and analyzing of literatures. Meaning of Nature-Study toward today's science education was considered. The research resulted in the following; First, Nature-Study emphasize the sympathy with nature, aim for integrated subject study and include non-formal study from a viewpoint of 'studying with nature'. Second, Nature-Study aim for outdoor activities, emphasize experiences than texts, value fundamental observation from a viewpoint of 'study through first-hand experiences'. Third, Nature-Study value interest of students, support the study for all students, emphasize the teachers' role as a helper from a viewpoint of 'learner-centered education'. Nature-Study is suggested to change view of point over to science education through nature toward today's science education.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.12
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• pp.1009-1016
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• 2007

Numerical study on preferential diffusion effects in flame structure in $CH_4-H_2$ diffusion flames is conducted with detailed chemistry. Comparison of flame structures with mixture-averaged species diffusion and suppression of the diffusivities of $H_2$ and H was made. Discernible differences in flame structures are displayed with three species diffusion models. The behaviors of maximum flame temperatures with those species diffusion models are not explained by scalar dissipation rate but by the nature of chemical kinetics. It is seen that the modifcation of flame structure is mainly due to the preferential diffusion of H2 and thereby the nature of chemical kinetics. It is also found that the behaviors of major species with the three species diffusion models are addressed to the nature of chemical kinetics, and this is evident by examining importantly contributing reaction steps to the production and destruction of those chemical species.

• Journal of the Korean Chemical Society
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• v.58 no.1
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• pp.118-125
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• 2014

This study purposes to historical approach the formation process of Nature-Study, and to re-evaluate its definition and direction at present. The idea of Nature-Study originated from Campanella, Ratke and Comenius, who emphasized real things. The idea developed through Object Lessons of Sheldon, the Natural History of Agassiz, and Progressivism of Parker. They acted as the main contributors who evolved the idea of Nature-Study and its core fields that involve: 'studying with real things' in Object Lessons which brought the methodical aspects to the idea, 'studying with nature' from Natural History that enhanced the content characteristics and 'learner-centered education' from Progressivism, which impacted the philosophical aspects. Straight (a fellow student of Agassiz) was a teacher for Sheldon Oswego normal school and Parker's Cook County normal school, who synthesized the fields together and paved the way for the formation of Nature-Study. Jackman of Cook Country normal school established Nature-Study as a school curriculum and Bailey and Comstock of Cornell University formed the American Nature-Study Society and as a result, Nature-Study started to gain popularity. However, many educators increasingly rejected Nature-Study as a unifying topic, and preferred the use of textbooks rather than firsthand experiences. This hindered the nature-study movement and it declined since the 1920s. But today, the Nature-study idea can play a huge role in developing science education, inclusive education centered nature, self-initiated retrieval, sympathy with nature and character building of students.

• Bulletin of the Korean Chemical Society
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• v.17 no.8
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• pp.669-671
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• 1996

• Bulletin of the Korean Chemical Society
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• v.20 no.3
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• pp.273-275
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• 1999

• Macromolecular Research
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• v.13 no.3
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• pp.236-242
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• 2005

Three dithioester-derived carboxyl acid functionalized RAFT(reversible addition-fragmentation chain transfer) agents, viz. acetic acid dithiobenzoate, butanoic acid dithiobenzoate and 4-toluic acid dithiobenzoate, were used in the RAFT bulk polymerization of styrene, in order to study the effects of the R-group structure on the living nature of the polymerization. By conducting the polymerization with various concentrations of the RAFT agents and at different temperatures, it was found that the R-group structure of the RAFT agents plays an important role in the RAFT polymerization; the bulky structure and radical stabilizing property of the R-group enhances the living nature of the polymerization and allows the polymerization characteristics to be well controlled.

• Bulletin of the Korean Chemical Society
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• v.9 no.1
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• pp.15-17
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• 1988

Titanium tetrachloride is purified using adsorption column packed with activated silica gel. When 120 ml of titanium tetrachloride was passed through an adsorption column filled with 7 g silica gel, iron content in titanium tetrachloride has been reduced from 7 ppm to less than 1 ppm, and aluminum from 46 ppm to 11 ppm, while silicon content being unchanged at about 60 ppm.