• Journal of Environmental Science International
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• v.14 no.12
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• pp.1203-1209
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• 2005

Basic dyes, Rhodamine 6G(R6G), Rhodamine B(RB), and Methylene Blue(MB), dissolved in water were used to investigate single-component adsorption affinity to the pearl layer fractionated according to the size. Unfractionated pearl layers were also used as adsorbents for the R6G and RB. The Langmuir and the Redlich-Peterson(RP) models were used to fit the adsorption data, and the goodness of fit was examined by using determination coefficient($R^2$) and standard deviation(SSE). The 3-parameter RP model was found to be better in describing the dye adsorption data than the 2 parameter Langmuir model, as can be expected from the number of parameters involved in the model. The adsorption affinity to the fractionated pearl layer was higher than that to the unfractionated layer The affinity order to the fractionated Conchiolin layer was found to be R6G > MB > RB. Furthermore, the dye adsorption capacity of the various types of pearl layer was found to be in the order, the fractionated pearl > powdered pearl > unfractionated pearl, exhibiting different adsorption isotherms according to the types of layer used in the study.

• Journal of Environmental Science International
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• v.14 no.12
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• pp.1195-1201
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• 2005

In order to develop a dye coloring technology on Conchiolin layer in cultured pearls, appropriate dyes were selected, their solubilities in various solvents were studied, and adsorption and desorption experiments were performed. Solubilities of several basic dyes known to suitable for the pearl coloring, i.e., Rhodamine 6G(R6), Rhodamine B(RB) and Methylene Blue(MB), in several solvents (distilled water, methanol, ethanol, and acetone) were investigated. Among these dyes, R6 was chosen as a dye for single component adsorption and desorption experiment due to the relatively good solubility in various solvents tested. Solubilities of dyes were judged to be enough to color the pearls since dye concentrations in pearl coloring are, in general, not so high. The internal surface area of the pearl layer is believed to be directly related to the dye adsorption, the single-point internal surface area of the pearl layer measured at the nitrogen relative pressure of 0.3 was found to be $0.913m^2/g$, and the BET internal surface area, $1.01m^2/g$ The most probable diameters of micropores and macropores were found to be $40{\AA}$and $5000{\AA}$ respectively, from the pore size distribution data. Adsorption isotherm was well fitted to the Langmuir isotherm model, resulting in q=$\frac{1.62C}{1+1.09C^{.}}$

• Journal of Fisheries and Marine Sciences Education
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• v.15 no.2
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• pp.219-225
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• 2003

So far, for pearl culture using abalones, a plastic nucleus has been planted in an abalone by perforating the shell. But after planing 80 % of abalones died, and even if they live, the pearl's hardness was not so good. The weak hardness made the pearl valueless. The quality of a pearl is decided by the gloss and the quality of the pearl's layer. This study is to find the right nucleus for abalones and to decrease a death rate of abalones by selecting the right planting place. This study was also performed to obtain valuable pearls with proper size, gloss, and good color. Below is the result of the research; Conch shells out of the various nucleus materials were the best. Their shape, color and gloss were very good. The nucleus was planted in the part that a shell is grown up under the absorption ball, as a result a pearl sack was quickly made. After 15 days, out of every pearl, pearl sacks were made. The pearl formation was measured every month. From the abalone shell which was planted in April, qualitative pearls which was from 5mm to 5.81mm in size were obtained in December.

• 한국해양학회지
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• v.24 no.2
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• pp.69-78
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• 1989

Cultivated pearls, composed of aragonite crystals, show two distinctive layers: nacreous and conchiolin organic layers. Each aragonite crystal is surrounded by organic matrix, which probably consists of amino acids. Nucleus, surrounded by pearl layer, also consists of nacreous crystals, suggesting that there is a close mineralogical and ultrasturctural relationship between pearl and nucleus. Carbon isotopic values of cultivated pearls are within the range of marine carbonate carbon. Oxygen isotopic composition indicates that the temperature for the growth of pearl and pearl oyster ranges from 16.4 to $21.4^{\circ}C$ and from 15.5 to $24.8^{\circ}C$, corresponding to the summer temperature range of the cultivating area. Elemental composition of pearl, pearl oyster, and nucleus shows that there is a difference in chemical composition depending upon the original mineralogy and the chemical composition of water in which shells grow. Especially, a strong relationship exists between pearl and the inner layer of pearl oyster because both are composed of nacreous aragonite and formed in a shallow marine environment.

• The Korean Journal of Malacology
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• v.28 no.2
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• pp.157-164
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• 2012

The patterns in X-ray diffraction (XRD) spectroscopy provide useful clue at $29.4^{\circ}$ to discriminate two types of Akoya cultured pearl which occurs difference of surface luster. Using the optical microscope, we could be confirmed that the nareous layer of each sample consist of different crystal form. In Fourier Transform Infrared (FT-IR) Spectroscopy analysis, the nareous layer of Akoya cultured pearls with poor luster shows some peaks at 712, 699, 1435, $1444cm^{-1}$ region and these peaks depend on the Calcite. But the nareous layer of pearls with excellent luster could not observed those peaks related with Calcite, we could observed Aragonite band at 699, $1085cm^{-1}$ region. Though this result, we know that the nareous layer of Akoya cultured pearls with excellent luster is mainly composed by Aragonite. Raman bands are also clearly demonstrated to occur difference of band intensity by difference of Aragonite content. In the Scanning Electron Microscope (SEM) analysis, we found that the Akoya cultured pearl luster and surface condition is associated with internal structure.

• Journal of the Mineralogical Society of Korea
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• v.28 no.1
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• pp.9-16
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• 2015

A mineralogical analysis on the factors affecting the luster of pearls was carried out using gravity measurement, optical microscope observation, X-ray diffraction analysis, and scanning electron microscopy. We divided the seawater cultured pearls from Tongyeong into the following four types based on luster and shape; good luster and round (LR), lackluster and round (LLR), lackluster and baroque (LLB), and lackluster and two nucleus (LTN) pearls. Pearls with high-quality luster had slightly lower specific gravity as compared to pearls with low-quality luster, but both these types of pearls are within the specific gravity range of commercial pearls. Regarding the cross-sectional thickness of the mother-of-pearl layer, LR pearls showed a uniform thickness of about 0.3 mm in average. On the other hand, LLR pearls were characterized by relatively thinner, but uniform thickness. LTN and LLB pearls showed a tendency of significantly large variation in thickness even within a single pearl. For the surface of pearls, pearls with high-quality luster showed narrower and clearer growth lines of aragonite crystals as compared to pearls with low-quality luster. Pearls with high-quality luster were characterized by fewer aragonite crystal lattice defects as compared to pearls with low-quality luster, and the former showed parallel arrangement, thinner thickness, and less difference in thickness on the surface and inside. If a pearl has a prismatic layer, it is composed of aragonite with calcite in the prismatic and nacreous layer, and calcite content is very high in the lackluster pearl. Pearls without a prismatic layer were devoid of calcite irrespective of their quality of luster, and were composed of aragonite.

• Journal of Technologic Dentistry
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• v.33 no.3
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• pp.219-224
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• 2011

Purpose: The current study focused on investigating color change of dental zirconia block with respect to the block coloring time. Methods: Three types of dental zirconia blocks(Zirtooth, Pearl-HT, D-Max) were tinted with coloring agent under four different time condition (0 minutes, 1 minutes, 10 minutes, 30 minutes). The quantitative evaluation of the tinted dental zirconia blocks was conducted with spectrophotometer. Results: The Zirtooth and D-Max blocks showed lower H value. The Pearl-HT blocks showed poor reflectivity(L value). Conclusion: The study of color change of zirconia block, which consists the substructure of all ceramic Crown, is applicable for deciding appropriate coloring condition when fabricating one layer ceramic Crown or double layer ceramic Crown.

• Journal of Aquaculture
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• v.1 no.1
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• pp.85-102
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• 1988

An experimental study on seedling production and wintering to develop pearl oyster, Pinctada fucata culture in Korea was carried out. from December 1986 to November 1988 in waters of Kori and of Seogwipo as wintering and of Eogu as culturing grounds. All pearl oysters as the sample were imported from Japan. The highest water temperature at Eogu was $23.6^{\circ}C$ in August and the lowest at Kori and Seogwipo were $13.2^{\circ}C$ and $14.0^{\circ}C$c in February, respectively, Phytoplankton was relatively plentiful but mortality of pearl oysters was $20.5\%$, which was twice at Seogwipo, due to high amount of suspended muds. It shows that Seogwipo is better wintering ground even though the amount of phytoplankton is lower than Kori. Average rates of pearl production after 6-months and 15-months period were $58.2\%$ and $48.3\%$ respecitively. Thickness of pearl layer and coating rate were also satisfactory. More than half of the pearls produced was so-called the pink-pearl, the best colour. About $10\%$ of them was the best quality. There were three peaks of D-shape larvae from July to September and it took about one month for D-shape larvae to become seed-shells. Settling was satisfactory and most of them settled at 1$\~$3 m layer and the best was 2 m-layer. Success of settling was supposed due to high water temperature and low precipitation than the normal year.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.2
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• pp.57-61
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• 2008

Non-nucleus Abalone half pearls were cultured by a new technique and their structural characteristics were analyzed using an electron microscopy. This technique was found to grow the pearls depending on the shape of the internal organ of an abalone because this technique induces the pearl layers without adding any nucleus on the specified damage region of a shell. The obtained pearls exhibit natural shapes with a specific luster. The SEM analysis shows that the pearl layers are about $0.34{\mu}m$ with an uniform thickness and the surface of the shell is characterized by the pyramid-shaped bulge with a regular arrangement, which is a typical feature of single-shell. These characteristics of the pearls are thought to develop in the highly-valued Korean gems.

• Applied Microscopy
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• v.29 no.3
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• pp.343-351
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• 1999

The structures of the fertilized egg envelope from three species, three-spot gourami (Trichogaster trichopterus), pearl gourami (Trichogaster leeri) and marble gourami (Trichogaster trichopterus trichopterus) belong to Belontiidae were observed, utilizing light, scanning and transmission electron microscopes. In all three species, the fertilized eggs were the colorless, transparent, spherical, adhesive and pelagic type. A large oil droplet was located in vitelline membrane of the fertilized egg. The egg envelopes have a single micropyle, which is thought to the pathway of sperm in the area of the animal pole. Specially, the micropyle of three-spot gourami was similar to that of marble gourami which is subspecies of three-spot gourami. An outer surface of the fertilized egg envelope was arranged by grooves in all three species. The fertilized egg envelopes consists of two distinct layers; an adhesive outer layer and an inner layer with high electron density. In conclusion, the morphological similarity of the fertilized egg, micropyle, outer surface and transverse section of the fertilized e9g envelope seems to be an indication of the Belontiidae.