• Conservation Science in Museum
• /
• v.30
• /
• pp.89-100
• /
• 2023

Museum collections are comprised of a variety of materials, and different scientific examinations are being conducted according to the types and production properties of the materials, but insufficient research has been carried out on ultra-small artifacts. To identify the material characteristics of the white ultra-small materials excavated from Geumnyeongchong tomb, this study carried out a wide range of non-destructive analyses (specific gravity, microscopy, nano-computed tomography (Nano-CT), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and Raman spectroscopy) and compared the said artifacts with the Goryeo-era burial accessories examined in prior research. Non-destructive analysis confirmed the presence of aragonite, which mainly consists of calcium carbonate (CaCO₃) as the constituent mineral, and identified the material used for the ornaments as the gemstone pearl based on its growth lines. This study concludes that pearls began to be used in the ancient Korean Peninsula in the 6^th century. It is expected that scientific examinations of the white ultra-small artifacts will yield information about the social culture of the time.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.6 no.4
• /
• pp.234-241
• /
• 2001

The degree of saturation of calcium carbonate in the East Sea was calculated from the data obtained from'99 expedition using R/V Roger Revelle. The calcium concentrations in seawaters were estimated from salinity data, and the carbonate ion concentrations were calculated from total alkalinity and pH data. The results suggest that the crossover from the supersaturation to undersaturation for calcium carbonate occur at the depth of approximately 200-400 m for calcite, and 100-300 m for aragonite. Compared to the Pacific and Atlantic oceans, these levels in the East Sea are shallow due to most likely lower temperature of sea water in this region.

• Journal of Energy Engineering
• /
• v.27 no.3
• /
• pp.48-56
• /
• 2018

The shell waste biomineralization process has known a tremendous metamorphosis and also the nanostructure with the identification of matrix proteins in oyster shells. However, proteins are represented in minor shell components and they are the major macromolecules that control biocrystal synthesis. Aragonite and calcite were derived from molluscan shells and evaluated the source of carbonate minerals and it helps for the formation of limestone. The oyster shell wastes are large and massive. The paleoecological study of oyster beds has discovered a near-shore and thin Upper Rudeis formation with storm influence during the accumulation of oysters with highly altered by disarticulation, bioerosion, and encrustation. It is possible even in the Paleozoic mollusks provided sufficient carbonate entirely to the source of microcrystalline of limestone. The present review is to discuss paleoecologically a number of oyster shell beds accumulated and sediment to form the different types of limestone during the Middle Miocene time.

• Journal of Energy Engineering
• /
• v.26 no.2
• /
• pp.73-79
• /
• 2017

In nucleation assisted crystallization process formed $CO_2$ leaves as colloid gas and is used as the template by the rapidly growing crystals in the nucleation site. This emulsion of $CaCO_3$ micro-crystals & $CO_2$ micro-bubbles forms hollow particles. Formed hollow particles are double walled, both internal and external faces belonging to the cleavage aragonites which separate the surrounding water from the enclosed gas cavity. Hence, the reverse reaction of $CO_2$ with water forming Carbonic Acid is not possible and the pH stability is maintained. In fact every excess $CaCO_3$ crystals are buffering any carbonic acid left over. This $CO_2$ based nucleation technology prevents scale formation in water channels, but it also helps to reduce the previously formed scales. This process takes out water dissolved $CO_2$ in almost-visible micro-bubbles forms that helps reducing previously formed scale over a period of time (depends on the usage period). The aragonite crystals can't form scale because of its stable molecular structure and neutral surface electro potentiality.

• Journal of the Korean Applied Science and Technology
• /
• v.27 no.1
• /
• pp.70-75
• /
• 2010

Scale generation in the inside of a pipe IS restricted by reduction and oxidation(REDOX) reaction of alloyed metal of Cu-Zn. To measure the scale generating rate in the 1.67 mm of inside diameter of stainless steel tube, 300 ppm of $CaCO_3$ solution is circulated in the REDOX reactor and stainless steel tube in the order. In the case of $CaCO_3$ solution treated by REDOX reactor, flowing is maintained without plugging in the stainless steel tube, and the concentration of Cu and Zn in the circulating solution showed less than 1 ppm, which is equal to that of untreated by REDOX reactor. The crystal type of $CaCO_3$ generated by crystalline nucleus of Cu or Zn, mostly showed aragonite type.

• Journal of the Korean Ceramic Society
• /
• v.51 no.1
• /
• pp.7-10
• /
• 2014

Abalone shell is composed of 95 wt% $CaCO_3$ platelets and 5 wt% of a protein-rich organic matrix which acts as an adhesive layer, connecting aragonite tablets, thus maintaining the structural integrity of the composite. By mimicking abalone shell, we prepared a silicate plate/polymer nanocomposite by infiltrating PMMA between silicate layers and warm-pressing them at $200^{\circ}C$ for 1 h under 15 tons to make organic-inorganic composite materials. To examine the organic-inorganic composite materials after the warm-pressing procedure, the composite sample was analyzed with FE-SEM and TG. The bending strengths and densities of the composites prepared by a silicate plate and PMMA after the warm-pressing process were ~140 MPa and 1.5, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.15 no.4
• /
• pp.152-156
• /
• 2005

The cultivation of akoya pearls was carried out with bio bead nucleus prepared using the hydroxyapatite. The akoya pearls cultured with bio bead nucleus were shown the color of cream. The luster and orient effect created by an action of the light from nacre were magnificent. The result of XRD is found that the nacre is a calcium carbonate of aragonite form. From the result of SEM, it is found that layers of calcium carbonate and conchiolin are stratified. The properties of akoya pearls cultured with bio bead nucleus are same those of akoya pearl cultivated with bead nucleus made from washboard shell. Because of the bio bead nucleus developed in this study has such a high capacity in producing various sizes and shapes, it is very advantageous for the cultivation of akoya pearls.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.49-54
• /
• 2003

Scale is formed when hard water is heated or cooled in heat transfer equipments such as heat exchangers, condensers, evaporators, cooling towers, boilers, and pipe walls. When scale deposits in a heat exchanging surface, it is traditionally called fouling. The objective of the present study was to compare the fouling characteristics of river and tap water in a heat exchanging model. FromtheSEM analyses for tap water the $calciteformofCaCO3_{3}$ was formed. For river water, however, the $aragoniteCaCO_{3}$ wasformed.In order to investigate velocity effects on the fouling characteristics in the heat exchanging model, the inlet velocity was varied with 0.5, 1.0 and 1.5 m/s, respectively. The fouling characteristics of river water were quite different from those of tap water. For the case of the 'velocity of 1.5m/s', the overall heat transfer coefficient was reduced up to 26% than that of the 'velocity of 0.5m/s'

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.48 no.1
• /
• pp.1-15
• /
• 2015

Tissue engineering is an emerging, innovative technology to improve or replace the biological functions of damaged tissues and organs. Scaffolds are important materials for tissue engineering as they support cell attachment, migration, and differentiation. Marine sponges naturally contain scaffolds formed by extracellular matrix proteins (collagen and sponging) and strengthened by a siliceous or calcium carbonate skeleton. Coral skeletons are also derived naturally formed by essential calcium carbonate in the form of aragonite, and are similar to human bone. In addition, collagen extracted from jellyfish is a biosafe alternative to bovine and porcine collagen and gained attention as a potential source for tissue engineering. Moreover, cuttlefish bone is an excellent calcium source and can be used to generate bio-synthetic calcium phosphate. It has become a natural candidate for biomimetic scaffolds. This review describes the use of natural products derived from marine invertebrates for applications in bone tissue engineering based on studies from 2008 to 2014.

• Current Optics and Photonics
• /
• v.1 no.4
• /
• pp.402-411
• /
• 2017

Combined LIBS-Raman spectroscopy has been widely studied, due to its complementary capabilities as an elemental analyzer that can acquire signals of atoms, ions, and molecules. In this study, the classification of polymorphs was performed by laser-induced breakdown spectroscopy (LIBS) to overcome the limitation in molecular analysis; the results were verified by Raman spectroscopy. LIBS signals of the $CaCO_3$ polymorphs calcite and aragonite, and $CaSO_4{\cdot}2H_2O$ (gypsum) and $CaSO_4$ (anhydrite), were acquired using a Nd:YAG laser (532 nm, 6 ns). While the molecular study was performed using Raman spectroscopy, LIBS could also provide sufficient key data for classifying samples containing different molecular densities and structures, using the peculiar signal ratio of $5s{\rightarrow}4p$ for the orbital transition of two polymorphs that contain Ca. The basic principle was analyzed by electronic motion in plasma and electronic transition in atoms or ions. The key factors for the classification of polymorphs were the different electron quantities in the unit-cell volume of each sample, and the selection rule in electric-dipole transitions. The present work has extended the capabilities of LIBS in molecular analysis, as well as in atomic and ionic analysis.