• Korean Journal of Heritage: History & Science
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• v.39
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• pp.243-280
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• 2006

At the Bujang-ri Site, Seosan, South Chungcheong Province, around 220 archaeological features, including semi-subterranean houses and pits of Bronze Age and semi-subterranean houses, pits, and burials of Baekje period had been identified and investigated. In Particular, mound burials No. 5 of 13 of Baekje mound burials yielding a gilt-bronze cap along with other valuable artifacts drew international scholarly attention. The gilt-bronze cap from the mound burial No. 5 is a significant archaeological data not only in the study of Baekje archaeology but also in the study of international affairs and exchange at that time. At the time of exposure, the gilt-bronze cap was already broken into a number of pieces and seriously damaged by corrosion, and hardening and urethane foam were necessary in the process of collecting its pieces. Ahead of main conservational treatments on cap, X-ray photograph and CT(computerizes tomography) were taken in order to examine interior structure of the cap and to decide appropriate treatments. In the five layers identified in the profile of cap, a textile layer was set between a metal and a layerof bark of paper birch for avoiding direct contact of the metal and the bark of paper birch. Analyses were executed for examining textile layer and a layer of fibroid material. According to microscopic analysis, while the textile layer consisted of the simplest plain fabric with one fold among three kinds of textile structures, the layer of fibroid material was mixed with two or three kinds of fibers. A comparative analysis with standard sample using FT-IR (Fourier Transform Infrared Spectroscopy) announced that both textiles and fabrics were hemp. Analysis of kind of the paper birch resulted in barks of paper birch with 15 fold. A metallographic microscope, SEM, and WDS were used for the analysis of microscopic structures of plated metal pieces. While amalgam plating was treated as a plating method, the thickness of the plated layer, a barometer of plating technique, was ranged from $1.72{\mu}m$ to $8.67{\mu}m$. The degree of purity of gold (Au) used in plating was 98% in average, and less than 1% of silver (Ag) was included.

• Resources Recycling
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• v.28 no.5
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• pp.60-67
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• 2019

A valuable metal recovery from waste resources such as spent rechargeable secondary batteries is of critical issues because of a sharp increase in the amount of waste resources. In this context, it is necessary to research not only recycling waste lithium-ion batteries (LIBs), but also reusing valuable metals (e.g., Li, Co, Ni, Mn etc.) recovered from waste LIBs. In particular, the lithium hydroxide ($LiOH{\cdot}xH_2O$), which is of precursors that can be prepared by the recovery of Li in waste LIBs, can be reused as a catalyst, a carbon dioxide absorbent, and again as a precursor for cathode materials of LIB. However, most studies of recycling the waste LIBs have been focused on the preparation of lithium carbonate with a recovery of Li. Herein, we show the preparation of high purity lithium hydroxide powder along with the precipitation process, and the systematic study to find an optimum condition is also carried out. The lithium carbonate, which is recovered from waste LIBs, was used as starting materials for synthesis of lithium hydroxide. The optimum precipitation conditions for the preparation of LiOH were found as follows: based on stirring, reaction temperature $90^{\circ}C$, reaction time 3 hr, precursor ratio 1:1. To synthesize uniform and high purity lithium hydroxide, 2-step precipitation process was additionally performed, and consequently, high purity $LiOH{\cdot}xH_2O$ powder was obtained.

• Applied Chemistry for Engineering
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• v.21 no.1
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• pp.52-57
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• 2010

Although chemical sedimentation and ion exchange are usually applied to the treatment of heavy metal ions and radioactive cations, they have some serious disadvantages like a great consumption of chemicals, the disposal of valuable metals, and the secondary pollution of soil by the solid-waste. The advanced countries recently have studied the electrochemical ion exchange, combined electrochemical reduction and ion exchange, for the development of the alternative technique. This study has been performed to investigate the optimum condition for the preparation of the nickel hexacyanoferrate (NiHCNFe) which is an electrochemical ion exchanger. NiHCNFe film was deposited on the surface of nickel plate by chemical method or electrochemical method. The morphology and composition of NiHCNFe were observed by SEM and EDS, respectively. The peak current density of NiHCNFe was measured from the cyclic voltammograms of the continuous oxidation-reduction reaction in a parallel plane ion exchange electrode reactor. It was found that the chemical preparation method was better than the electrochemical method. The concentrated NiHCNFe was apparently deposited on nickel plate when dipping in the preparing solution for 118 h, especially. It also had a best durable performance as an ion exchange electrode.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.1
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• pp.87-94
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• 1992

The purpose of this study was to evaluate the effect of scatter radiation to dental x-ray film with long time-exposure in the different structures of the tooth, by using pinhole camera. For this study, pinhole camera, skull with tooth, and pocket dosimeter were used. The radiation with 70 and 90kVp and exposure time (minimum: 2.5 min., maximum 10 hrs.) was projected to the film in the pinhole camera. And density of the obtained x-ray film was measured with densitometer. In the intra-oral film taking, the amount of exposure of the scatter radiation affecting the thyroid gland area was measured with the dosimeter at the thyroid gland. The density of radiographs was compared in radiation projected with or without the metal cone of dental machine. The effect of the back scatter radiation to the film was also evaluated when the lead foil was removed. The obtained results were as follows: 1. A pinhole camera was a valuable device for locating the source of x-ray. 2. The scatter radiation affected the dental x-ray film when the radiation source was exposed. more than 5 hours'. In that case, the density of the scatter radiation could be observed visually. 3. The scatter radiation caused by short exposure of dental radiation didn't affect the diagnostic quality of the dental x-ray film. 4. The differences of densities between the tooth and the soft tissue according to exposure time showed 0.16 in 5 hours' exposure & 0.17 in 10 hours' exposure at 70 kVp & 0.12 in 5 hours' exposure & 0.13 in 10 hours' exposure at the 90kVp. 5. The differences of densities between the tooth and the soft tissue according to kVp showed no difference between 5 hours' exposure of tooth at 70 kVp and soft tissue at 90 kVp, but showed 0.05 high density in tooth when 10 hours' exposure at 90 kVp. 6. No difference of density was on radiographs taken with or without dental machine cone. 7. Back scatter radiation was recorded image of radiographs for only 3 min. 8. The amounts of the scatter radiation exposed to the thyroid gland in intraoral film taking were 1.12 mr in upper anterior, 0.55 mr in upper posterior, 2.75 mr in lower anterior, and 1.92 mr in lower posterior teeth.

• Resources Recycling
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• v.20 no.3
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• pp.48-54
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• 2011

Sulphuric acid leaching was conducted to extract the metal values from spent refinery catalyst. More than 95% of Ni and V and 30% of Mo could be leached out in 1 M sulphuric acid and 1 hr of leaching time. The decrease in Mo leaching was due to typical characteristic of Mo matrix. The activation energies of the leaching reactions showed the dissolution process follows a diffusion control mechanism. In order to leach out all Mo, further the leaching experiments were conducted with sulfur free spent refinery catalyst. For sulfur free spent refinery catalyst, a two step process of leaching with 1 M sulphuric acid followed by sodium carbonate washing showed better leaching than a two step leaching process with sodium carbonate followed by sulphuric acid washing, with almost 99% leaching of Ni, Mo and V. Solvent extraction using LIX 841 were conducted for a leach liquor containing Ni, 2 g/L; V, 9 g/L, Mo, 0.6 g/L. More than 98% of Mo was extracted from the leach liquor at A:O ratio of 5:2 in a 2 stage process. Similarly V was extracted at A:O ratio of 5:3 in a 2 stage process with 82% of total V extraction.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.186-195
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• 2011

Historically, Korea has made and weaved beautiful jewelry based on delicate metal craft technique. Especially jewelries in Chosun dynasty among these jewelry shows practicality, fanciness and social symbolism at the same time, which is one of representative cultural origins to express characteristics of Korean culture. Since jewelry of imperial princess YEONG, an object of a study herein, was made for a court ceremony although it is an artifact of the end of Chosun dynasty after the time of enlightenment, it is expected be made based on traditional shape and standard in accordance with strictly respected court dress code in Chosun dynasty. It is also an important data of research for a court style and system as well as its artistry in its diversity of type, preservation condition similar to original form and its producers who are master craftsman parted in Sang-Uiwon (an institute in charge of dress and accessaries of court) at the end of dynasty. Thus, a study herein aims to research formatively valuable 11 selected jewelries among jewelries of imperial princess YEONG used at the end of Chosun dynasty, and search for industrial application method with digitalization of the shape and design and preservation of original form of traditional culture. Moreover, in accordance with proposing design data through review of traditional women jewelry, it aims to suggest possibility of application into modern jewelry design and cultural industry.

• Journal of the Korean Society of Costume
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• v.35
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• pp.17-44
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• 1997

Medieval European practical art and style of costume is studied through referring to the literatures. The type of clothing that was seen on tapestries arts and crafts paintings and wall paintings and appeared in the architecture such as church. There were symbolic aspects of color motifs at this period and some restraints for clothing according to the social class, It was a period that draped garments due to the War of Crusades is appeared. Be-cause the medieval taste and decorative character is not only 'formative art' but also the taste beyoud 'mode' and atomsphere of that times it could be seen the strong reflec-tion of customs in the clothing of that times which is shown in works of art. 1) The purpose of Christian art which was found in mosaics stained glasses wall pain-tings and statues of architecture was not just the revival of natural phenomena but visuali-zation of sacred and invisible things. It was valuable to understandin of the spiritual through the sense organ It was a monumental art that was combined with decorative func-tion and role of the Bible. It revealed what was about the religious spiritual miracle, 2) In the medieval European painting characteristic and beautiful creativity was the basis of an argument. Both "Worship of East-ern" that is painted ion a parchment and "Cor-onation of Charles VI" were described decor-ation motifs on the edge of buildings geo-metric patterns and others with outstanding skill. there were precise technologic skill of architect and glassmen and lots of patience of craftsmen. " The Labour of the Months" and the scene of"A Trial at the Court" is also de-scribed elaborately. 3) Tapestry was developed in France Ger-many Swiss at the 14th century. Religionary and historical themes unicorn lady bird flowering plants and others were major motifs. It was very important as decorative wall coverings and as practical door arch and bed hangings. It was made through patient hard work with simple technique and it was con-sidered as an art for practical use. Tapestry was what everyone wish to have. It is reckoned for the item of the best gift. The royalty and nobility ordered and used custom-made tapestries. Sometimes the subject of motifs consisted of series which were deeply related to living 4) Decorative arts and crafts was the art that used materials such as precious metals jewels and others and that accorded with the luxurious and gorgeous taste of the royalty and nobility. Christian considered splendid and beautiful color of light as a symbol of glory. They used also for church appliances, There were metal crafts wood crafts textile crafts and others, As was stated above the costume appeared on the arts and crafts for living revealed the process of changes saw how the politic econ-omic and social organizations were developed.and social organizations were developed.

• Microbiology and Biotechnology Letters
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• v.34 no.1
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• pp.28-34
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• 2006

A native extracellular acid phosphatase, phytase (EC 3.1.3.8), from Bacillus coagulans IDCC 1201 (commercially known as Lactobacillus sporogenes) used as probiotics, was characterized. Though some strains of B. coagulans have been evaluated with regard to several health-promoting effects, it has not been reported to produce phytase. Partially purified phytase front the strain IDCC 1201 had a pH optimum of 4.0 and a temperature optimum of $50^{\circ}C$, respectively. The requirement for divalent cations was studied and cobalt ion remarkably increased the enzyme activity. The removal of metal ions from the enzyme by EDTA decreased activity below 50%. The enzyme activity depleted restored when the assay was performed in the presence of $Co^{2+}$. Also, $Co^{2+}$ is the most active stimulator and has unique activation effect at high temperature. The phytase was specific for sodium phytate and p-nitrophenylphosphate, which is different from other known Bacilli phytases. The putative amino acid sequences of the phytase from B. coagulans IDCC 1201 were very similar to that of the phytase from B. subtilis strain 168. Based on these data, we concluded that the phytase from B. coagulans IDCC 1201 is a $Co^{2+}$-dependent acid phosphatase. Therefore, the strain B. coagulans IDCC 1201 is thought to be a valuable addititive for livestocks as well as a beneficial probiotics for human.

• Journal of Microbiology and Biotechnology
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• v.21 no.10
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• pp.1012-1020
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• 2011

A gene coding for an endoglucanase (EglA), of the glycosyl hydrolase family 12 and derived from Aspergillus niger VTCC-F021, was cloned and sequenced. The cDNA sequence, 717 bp, and its putative endoglucanase, a 238 aa protein with a predicted molecular mass of 26 kDa and a pI of 4.35, exhibited 98.3-98.7% and 98.3-98.6% identities, respectively, with cDNA sequences and their corresponding endoglucanases from Aspergillus niger strains from the GenBank. The cDNA was overexpressed in Pichia pastoris GS115 under the control of an AOX1 promoter with a level of 1.59 U/ml culture supernatant, after 72 h of growth in a YP medium induced with 1% (v/v) of methanol. The molecular mass of the purified EglA, determined by SDS-PAGE, was 33 kDa, with a specific activity of 100.16 and 19.91 U/mg toward 1% (w/v) of ${\beta}$-glucan and CMC, respectively. Optimal enzymatic activity was noted at a temperature of $55^{\circ}C$ and a pH of 5. The recombinant EglA (rEglA) was stable over a temperature range of $30-37^{\circ}C$ and at pH range of 3.5-4.5. Metal ions, detergents, and solvents tested indicated a slightly inhibitory effect on rEglA activity. Kinetic constants ($K_m$, $V_{max}$, $k_{cat}$, and $k_{cat}/K_m$) determined for rEglA with ${\beta}$-glucan as a substrate were 4.04 mg/ml, 102.04 U/mg, 2,040.82 $min^{-1}$, and 505.05, whereas they were 10.17 mg/ml, 28.99 U/mg, 571.71 $min^{-1}$, and 57.01 with CMC as a substrate, respectively. The results thus indicate that the rEglA obtained in this study is highly specific toward ${\beta}$-glucan. The biochemical properties of rEglA make it highly valuable for downstream biotechnological applications, including potential use as a feed enzyme.

• Resources Recycling
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• v.9 no.1
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• pp.52-62
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• 2000

In order to maximize the recycling of converter slag to the more valuable fields, such as high quality aggregates for construction, cement industry and flux for ion making. It will be very important to control the compositions and properties of converter slag to suit the purpose of utilizastion. In this study, converter slag (STELCO, CANADA) was mixed with 5%~30% $SiO_2$and 7% carbon, and then reduced at $1650^{\circ}C$. After the reduction was completed, the reformed slags were cooled to room temperature in the furnace. All of the slags were then characterized using SEM-EDX, XRD and chemical analysis. Also the compressive strengths and densities of the reformed slags were measured to compare with natural aggregates. XRD analysis shows that th phases of reformed slags are changed from bredigite+merwinite mixed phases of 10% $SiO_2$added reduction to akermanite phases of 20% and 30% $SiO_2$ added reduction. But the SEM-EDX analysis revealed that the phase distribution of the reformed slags was changed very sensitively and complicately depends on the change of slag compositions. And also the properties of reformed slags are changed very much depend on the phase distribution. About one third of Cadmium and on fifth of Vanadium are remained in reduction reformed converter slag. Another heavy metal elements such as cobalt, zinc, lead are removed up to more than 90-95% of original slag. The compressive strength and density of 25% $SiO_2$ added and reformed slag is very near to natural granite. This is superior more than 10% to Thyssen's $SiO_2$ added and oxidized converter slag aggregates.