• Economic and Environmental Geology
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• v.56 no.1
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• pp.23-53
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• 2023

In this review paper, previous studies on layered double hydroxides (LDHs) published in the Korean Citation Index (KCI) were examined to investigate a research trend for LDHs in Korea. Since the first publication in 2002, 160 papers on LDHs have been published until January 2023. Among the 31 academic fields, top 5 fields appeared in the order of chemical engineering, chemistry, materials engineering, environmental engineering, and physics. The chemical engineering shows the highest record of published paper (71 papers) while around 10 papers have been published in the other four fields. All papers were reclassified into 15 research fields based on the industrial and academic purposes of using LDHs. The top 5 in these fields are in order of environmental purification materials, polymer catalyst materials, battery materials, pharmaceutical/medicinal materials, and basic physicochemical properties. These findings suggest that researches on the applications of LDH materials in the academic fields of chemical engineering and chemistry for the improvement of their functions such as environmental purification materials, polymer catalysts, and batteries have been being most actively conducted. The application of LDHs for cosmetic and agricultural purposes and for developing environmental sensors is still at the beginning of research. Considering a market-potential and high-efficiency-eco-friendly trend, however, it will deserve our attention as emerging application fields in the future. All reclassified papers were summarized in our tables and a supplementary file, including information on applied materials, key results, characteristics and synthesis methods of LDHs used. We expect that our findings of overall trends in LDH research in Korea can help design future researches with LDHs and suggest policies for resources and energies as well as environments efficiently.

• Korean Journal of Heritage: History & Science
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• v.55 no.4
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• pp.138-164
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• 2022

The Neolithic shell midden in Daejuk-ri, Seosan, is distributed on the gentle slope of a low hill close to the west coast. The bedrock of the area consists mainly of schist with various mafic minerals, but shows a partial gneiss pattern. The site consists of loamy topsoil and clay loam subsoil, and the degree of siallization is relatively low. Although the pottery excavated from the shell midden shares mostly similar features, a variety of shapes and patterns coexist. The surface colors, thickness and physical properties are slightly different. The pottery can be subdivided into three types (IA, IB and II) according to the composition of the body clay, the temper and the existence of a black core. Types IA and IB are colorless mineral pottery with a non-black or black core respectively. TypeII is colored mineral pottery with a non-black core. Type I pottery also contains non-plastic colored minerals, but type II contains a large amount of biotite, chlorite, talc, amphibole, diopside and tremolite, which include a large amount of Mg and Fe. The studied pottery contains a small amount of organic matter. Considering the grain size and relatively poor sorting and roundness of the non-plastic particles, the pottery appears to be made by adding coarse non-plastic tempers for special purposes to the untreated weathered soil around the site. The three types of pottery seem to have been incompletely fired in general. While type IB has the lowest degree of oxidation, typeII shows the highest degree of redness and oxidation. It can be interpreted that these differences depend on the firing temperature and the ratio of non-plastic particles. Through a synthesis of the minerals, geochemical data and thermal history, it can be determined that the firing temperature ranged from 600 to 700℃. The pottery types of the Daejuk-ri Shell Midden have slightly different production conditions, mineral compositions, and physical properties, but have undergone similar production processes with basically the same clay materials. The clay is almost identical to the composition of the bedrock and weathered soil distributed in the Daejuk-ri area. Currently, there is an industrial complex in the area, so it is difficult to confirm the soil and geological distribution of the site. However, it is highly probable that the area around the site was self-sufficient for the clay and tempers required for the production of the Neolithic pottery. Therefore, it can be interpreted that the group that left the shell midden in Daejuk-ri lived near the site, visited the site for the purpose of collecting and processing shellfish, and discarded the broken pottery along with shells.