• Conservation Science in Museum
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• v.26
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• pp.161-182
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• 2021

A jungwangu, a type of medium-sized mortar, is a firearm with a barrel and a bowl-shaped projectileloading component. A bigyeokjincheonroe (bombshell) or a danseok (stone ball) could be used as a projectile. According to the Hwaposik eonhae (Korean Translation of the Method of Production and Use of Artillery, 1635) by Yi Seo, mortars were classified into four types according to its size: large, medium, small, or extra-small. A total of three mortars from the Joseon period have survived, including one large mortar (Treasure No. 857) and two medium versions (Treasure Nos. 858 and 859). In this study, the production method for medium mortars was investigated based on scientific analysis of the two extant medium mortars, respectively housed in the Jinju National Museum (Treasure No. 858) and the Korea Naval Academy Museum (Treasure No. 859). Since only two medium mortars remain in Korea, detailed specifications were compared between them based on precise 3D scanning information of the items, and the measurements were compared with the figures in relevant records from the period. According to the investigation, the two mortars showed only a minute difference in overall size but their weight differed by 5,507 grams. In particular, the location of the wick hole and the length of the handle were distinct. The extant medium mortars are highly similar to the specifications listed in the Hwaposik eonhae. The composition of the medium mortars was analyzed and compared with other bronze gunpowder weapons. The surface composition analysis showed that the medium mortars were made of a ternary alloy of Cu-Sn-Pb with average respective proportions of (wt%) 85.24, 10.16, and 2.98. The material composition of the medium mortars was very similar to the average composition of the small gun from the Joseon period analyzed in previous research. It also showed a similarity with that of bronze gun-metal from medieval Europe. The casting technique was investigated based on a casting defect on the surface and the CT image. Judging by the mold line on the side, it appears that they were made in a piece-mold wherein the mold was halved and using a vertical design with molten metal poured through the end of the chamber and the muzzle was at the bottom. Chaplets, an auxiliary device that fixed the mold and the core to the barrel wall, were identified, which may have been applied to maintain the uniformity of the barrel wall. While the two medium mortars (Treasure Nos. 858 and 859) are highly similar to each other in appearance, considering the difference in the arrangement of the chaplets between the two items it is likely that a different mold design was used for each item.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.413-422
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• 2022

Barnea manilensis is a bivalve which bores soft rocks, such as, limestone or mudstone in the low intertidal zone. They make burrows which have narrow entrances and wide interiors and live in these burrows for a lifetime. In this study, the morphology and the microstructure of the valve of rock-boring clam B. manilensis were observed using a stereoscopic microscope and FE-SEM, respectively. The chemical composition of specific part of the valve was assessed by energy dispersive X-ray spectroscopy (EDS) analysis. 3D modeling and structural dynamic analysis were used to simulate the boring behavior of B. manilensis. Microscopy results showed that the valve was asymmetric with plow-like spikes which were located on the anterior surface of the valve and were distributed in a specific direction. The anterior parts of the valve were thicker than the posterior parts. EDS results indicated that the valve mainly consisted of calcium carbonate, while metal elements, such as, Al, Si, Mn, Fe, and Mg were detected on the outer surface of the anterior spikes. It was assumed that the metal elements increased the strength of the valve, thus helping the B. manilensis to bore sediment. The simulation showed that spikes located on the anterior part of the valve received a load at all angles. It was suggested that the anterior part of the shell received the load while drilling rocks. The boring mechanism using the amorphous valve of B. manilensis is expected to be used as basic data to devise an efficient drilling mechanism.

• Journal of radiological science and technology
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• v.26 no.3
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• pp.33-39
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• 2003

Purpose : Be aware of clinical possibilities on image quality by comparison of contrast-enhanced dynamic CT and MR imaging applied of MIP technique after the experimentally induced clonorchasis infection in dogs. Materials and Method : Twenty mongrel dogs prepared in zoo-laboratory were followed up with serial CT scans and MR imaging for 13 weeks after the experimental infection in liver. Two-phase helical CT was acquired in the supine position with the following scanning parameters. After the injection of contrast material, the arterial phase was initiated using a bolus-racking method. The portal phase scan was started 15 seconds after the arterial phase scan. CT protocol was determined after single level dynamic scans. MR imaging used the CP body coil and images get a 2D image using HASTE, FLASH, TSE pulse sequence. Bile duct MR imaging were obtained in three plans. Then each image was post processed by using target MIP algorithm. Two experimentation above, as a method of evaluation, one pathologist, three radiologist and five radiological technologist were analyzed visually for evaluation of following findings, enhancement of the bile duct wall, dilatation of bile duct tip, liver parenchyma, background suppression. Results : Five dogs was died of a disease after the infection, the rest one else shows the chronic dilatation of the intrahepatic bile duct with CT and MR imaging. Contrast administration of CT shows the contrast-enhanced of the bile duct walls with live parenchyma. MR imaging calculated of CNR and CR from pulse sequence for comparative evaluation and shows the pattern of the intrahepatic bile duct, dilatation of bile duct tip using MIP technique. CNR of the clonorchiasis, HASTE was $16{\pm}0.83$, TSE $7.06{\pm}3.0$, FLASH $1.19{\pm}0.2$ and CR, HASTE was 73.3%, TSE 62.3%, FLASH 6.4%. Conclusion : CT and MR imaging is very usefulness in diagnosis of dog clonorchiasis.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.3
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• pp.165-176
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• 2014

Purpose: The effects of desensitizing agent are often for a short duration. One of the reasons is believed to be wear of desensitizing agent by tooth brushing. To reduce the wear and make the duration longer, dental bonding resin was applied and the changes of dentin permeability after toothbrushing were measured. Materials and methods: Extracted teeth free from caries were chosen. Coronal dentin discs with thickness of 1 mm were prepared. Using the split chamber device developed by Pashely, hydraulic conductance and scanning electron microscope images (SEM) were compared and contrasted before and immediately after the application of desensitizing agent and bonding resin and then after equivalent tooth brushing of 1 week, 2 weeks, and 6 weeks. Four commercially available desensitizing agents were used in this study; they were All-Bond 2, Seal & Protect, Gluma, and MS Coat. And Dentin/Enamel Bonding resin (Bisco Inc.) was used. The results of this study are as follows. Results: On all specimens, the hydraulic conductance decreased after the application of tooth desensitizing agent and bonding resin. Compared with the specimens treated only with desensitizer, the specimens treated with All-Bond 2, Gluma, MS Coat and plus D/E bonding resin had a little increase in hydraulic conductance after 1, 2 and 6-week tooth brushing. In case of Seal & Protect, the specimens showed the same result only after 6-week tooth brushing. On examination of SEM, the dentinal tubule diameter had decreased after treatment of desensitizing agents and bonding resin. And the specimens treated with All-Bond2, Seal&Protect, Gluma, MS Coat and plus D/E bonding resin had an significant decrease in diameter of dentinal tubule after 6-week tooth brushing. Conclusion: According to the results of this study, it is effective to use bonding resin after application of desensitizer in reducing the wear by tooth brushing and making the duration longer. In this study, just 6-week tooth brushing was performed, and it is not enough to regard it as a long-term data. So further study is needed and more perfect method for treating dentin hypersensitivity should be developed.

• Tuberculosis and Respiratory Diseases
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• v.55 no.1
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• pp.41-58
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• 2003

Background : The resurgence of tuberculosis and the widespread emergence of multidrug-resistant M. tuberculosis have emphasized the importance of rapid and accurate diagnostic procedures. Recently, the oligonucleotide chip has proven to be a useful tool in the rapid diagnosis of infectious diseases. The purpose of this study was to rapidly and accurately detect specific mutations in the rpoB, katG and rpsL genes associated with rifampin, isoniazid and streptomycin resistance in M. tuberculosis, respectively, using a single oligonucleotide chip. Method : For detection of drug-resistance, 7 wild-type and 13 mutant-type probes for rifampin, 2 wild-type and 3 mutant-type probes for isoniazid, and 2 wild-type and 2 mutant-type probes for streptomycin were designed and spotted onto glass slides. Fifty-five cultured samples of M. tuberculosis were amplified by PCR, and then underwent hybridization and scanning. Direct sequencing was done to verify the results from the oligonucleotide chip and to analyze the types of mutations. Result : Thirty-five cases out of 40 rifampin-resistant strains(~88%) had mutations in the rpoB gene. One case had a new mutation(D516F, GAC R TTC) and another known mutation together. Twenty cases out of 42 isoniazid-resistant strains(~50%) had mutations in the katG gene, while 7 cases out of 9 streptomycin-resistant strains(~78%) had mutations in the rpsL gene. From these results, the oligonucleotide chip was confirmed to be able to detect the most frequent mutations from the genes associated with rifampin, isoniazid and streptomycin resistance. The results proved that the drug-resistance detection probes were specific. When the results from the oligonucleotide chip and DNA sequencing were compared, the types of mutations were exactly matched. Conclusion : The diagnostic oligonucleotide chip with mutation specific probes for drug resistance is a very reliable and useful tool for the rapid and accurate diagnosis of drug resistance against rifampin, isoniazid and streptomycin in M. tuberculosis infections.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.4
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• pp.337-344
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• 2015

Purpose: The purpose of present study is to examine the correlation between the accuracy of abutment preparation and the marginal adaptation of metal coping. With this view, this study compared the correlations regard to the three different manufacturing methods of selective laser sintering technique, milling and casting. Materials and methods: Two master models were made in a different way. First model with deep chamfer margin was prepared directly by a general clinician and the second model was designed by 3-D designing software program with the same abutment preparation principle and produced by computer aided manufacturing. 12 Co-Cr alloy copings were produced respectively with three different method; SLS system, CAD/CAM milling and conventional lost wax technique from each master model. The total 72 copings fully sit on the master model were stereoscopically evaluated at 40 points along the entire circumferential margin. Results: Significant differences in the absolute marginal discrepancies of Co- Cr copings from SLS system (P=.0231) and casting method (P<.0001) were shown between hand preparation model and computer designed model. However, no significant difference was found between the two model groups from milling method (P=.9962). Conclusion: Within the limitation of this study, the effect of the accuracy of abutment preparation on the marginal adaptation of Co-Cr coping is statistically significant in SLS system and casting group. The copings produced by SLS system exhibited the lowest marginal discrepancies among all groups, and the marginal gap of this method group was influenced by the accuracy of the abutment preparation.

• Journal of Embryo Transfer
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• v.22 no.1
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• pp.53-61
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• 2007

This study was investigated factors affecting the pregnancy rates after transfer of pronuclear microinjected embryos for the production of transgenic Korean black goats. Embryo transfer was carried out in 343 recipient Korean black goats from September 1999 to June 2000. Estrus was induced by the insertion of intravaginal progesterone devices $CIDR^(R)$ for 2 weeks. A single injection of 400 IU equine chorionic gonadotropin was administered at 48h before $CIDR^(R)$ removal to increase the proportion of does cycling and ovulation rate. Good quality embryos were prepared by microinjection of DNA into the pronuclei of fertilized goat oocyte and cultured in vitro. Pronuclear microinjected $1{\sim}8$ cell stage embryos were surgically transferred into the oviducts of the recipient at day 4 or 5 following $CIDR^(R)$ removal, and morula to blastocyst stage embryos were surgically transferred into uterus at day 9. Pregnancy was diagnosed by transrectal ultrasound scanning at $20{\sim}30d$ and 8 weeks following embryo transfer. The pregnancy rate was affected by several factors, such as estrus induction, the number of previous transfer, transfer site, stage of CL (corpus luteum), the number of recipient CL, stage of embryos and the number of transferred embryo. The pregnancy rate was significantly higher in recipients that came into estrus naturally than recipients that induced to come into estrus with $CIDR^(R)$(59.1% vs. 36.8%; P<0.05). The pregnancy rate was higher when the embryos were transferred into the left oviduct than transferred into the right oviduct (42.9% vs. 35.3%; P<0.05). The pregnancy rate of recipients with $CH_1$ (early) stage corpus hemorrhagicum in ovary was hi틴or than recipient with $CH_3$ (late) stage hemorrhagicum (47.5% vs. 17.9%; P<0.01). Higher pregnancy rates were obtained by transfer of 1-cell stage embryos into oviduct while late blastocysts (51.6% vs. 66.7%; P<0.01) into uterus. The pregnancy rates when 3 embryos were transferred to recipients were significantly higher than when 2 embryos we.e transferred (47.6% vs. 27.0%; P<0.05). Although there were no significant difference among the group, adhesion of reproductive organs, uterine size, ovulation rate of recipients, presence of large follicle and difficulty of transfer affected pregnancy rate of recipient. Higher pregnancy rates were obtained in the recipients with $8{\sim}15m$ diameter uterine horn as compared to the recipients with <5m diameter or >20mm diameter uterine hem (38.9%, 20% vs. 18.2%), in the recipients with large follicle in the ovulated ovary ipsilaterally (53.6% vs. 37.1%) and in the transfer which was carried out easily (39.2% vs. 27.8%, 0%). In conclusion, the high rate of pregnancy was achieved following transfer of pronuclear microinjected embryos when three or four 1-cell stage embryos were transferred into oviduct with $CH_1$ stage corpus hemorrhagicum in the ovary of recipient which came into estrus naturally.

• Journal of Technologic Dentistry
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• v.21 no.1
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• pp.27-41
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• 1999

The Ag-Pd-Cu alloys containing a small amount of Au is commonly used for dental purposes, because this alloy cheaper than Au-base alloys for clinical use. However, the most important characteristic of this alloy is age-hardenability, which is not exhibited by other Ag-base dental alloys. The specimens used were Ag-30Pd-10Cu ternary alloy and Au addition alloy. These alloys were melted and casted by induction electric furnace and centrifugal casting machine in Ar atmosphere. These specimens were solution treated for 2hr at $800^{\circ}C$ and were then quenched into iced water, and aged at 350-$550^{\circ}C$ Age-hardening characteristic of the small Au-containing Ag-Pd-Cu dental alloys were investigated by means of hardness testing, X-ray diffraction and electron microscope observations, electrical resistance, differential scanning calorimetric, energy dispersed spectra and electron probe microanalysis. Principal results are as follows ; Maximum hardening occured in two co-phases of ${\alpha}_2$ + PdCu In stage II, decomposition of the $\alpha$ solid solution to a PdCu ordered phase($L1_o$ type) and an Ag-rich ${\alpha}_2$ phase occurred and a discontinuous precipitation occurred at the grain boundary. From the electron microscope study, it was concluded that the cause of age-hardening in this alloy is the precipitation of the PdCu redered phase, which has AuCu I type face-centered tetragonal structure. Precipitation procedure was ${\alpha}{\to}{\alpha}_1+PdCu{\to}{\alpha}_2+PdCu$ at Pd/Cu = 3 Pd element of Ag-Pd-Cu alloy is more effective dental alloy on anti-corrosion and is suitable to isothermal ageing at $450^{\circ}C$.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.89-100
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• 2005

The purpose of this study was to analyze the morphometrics of primary second molar and permanent first molar. Samples were consisted of normal occlusion in the primary dentition(50 males and 50 females) and permanent dentition(43 males and 43 females). Their upper and lower plaster casts were used and their measuring points were decided, through 3-dimensional laser scanning(3D Scanner, DS4060, LDI, U.S.A.), fitting standard horizontal plane were made for measuring the intercuspal distance, volume of intercuspal area and section curve. The results were as follows; 1. Average distance from the fit plane to the cusp tips of mandibular primary second molar was smaller than any other tooth. (0.05-0.09 mm in male and 0.04-0.09 mm in female). 2. Intercuspal distances of mandibular primary second molar and permanent first molar were larger in male than in female. Especially, there was statistical significance in primary second molar(p<0.05). 3. Intercuspal distance between distobuccal and distolingual cusp was larger in maxillary primary second molar, except cross intercuspal distances. And distances between distal and distolingual cusp, in mandibular primary second molar, between mesiolingual and mesiobuccal cusp, in maxillary first molar, and between distolingual and mesiolingual cusp, in mandibular first molar were larger than any other intercuspal distance. 4. Volume of intercuspal area of primary second molar and permanent first molar was larger in mandible than in maxilla and that of permanent first molar was 1.40-1.75 times of primary second molar (p<0.05). Also it was larger in male than in female, but there was no statistical significance. 5. In most cases, section curves were wider and deeper in permanent dentition than in primary dentition. Except cross intercuspal distances, in maxilla, section curve between mesiobuccal and mesiolingual cusp was the deepest in both dentition. In mandible, section curve between distobuccal and distal cusp was the deepest in permanent dentition and between distolingual and distal cusp was the deepest in primary dentition.

• Journal of Technologic Dentistry
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• v.19 no.1
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• pp.21-35
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• 1997

The Ag-Pd-Cu alloys containing a small amount of Au is commonly used for dental purposes, because this alloy is cheaper than Au-base alloys for clinical use. However, the most important characteristic of this alloy is age-hardenability, which is not exhibited by other Ag-base dental alloys. The specimens used were Ag-20Pd-20Cu ternary alloy and Au addition alloy. These alloys were melted and casted by induction electic furace and centrifugal casting machine in Ar atmoshpere. These specimens were solution treated for 2hr at $800^{\circ}C$ and were then quenched into iced water, and aged at $350{\sim}550^{\circ}C$ Age-hardening characteristics of the small Au-containing Ag-pPd-Cu dental alloys were investigated by means of hardness testing, X-ray diffraction and electron microscope observations, electrical resistance, differential scanning calorimetric, emergy dispersed spectra and electron probe microanalysis. Principal results are as follows : Hardening occured in two stages, I. e., stage I in low temperature and stage II in high temperature regions, during continuous aging. The case of hardening in stage I was due to the formation of the Llo type face centered tetragonal PdCu-ordered phase in the grain interior and hardening in stage I was affedted by the Cu concentration. In stage II, decomposition of the $\alpha$ solid solution to a PdCu ordered phase(L1o type) and an Agrich ${\alpha}2$ phase occurred and a discontiunous precipitation occurred at the grain boundary. Form the electron microscope study, it was concluded that the cause of age-hardening in this alloy is the precipitation of the PdCu ordered phase, which has AuCu I type face-centered tetragonal structure. Precipitation procedure was ${\alpha}\to{\alpha}+{\alpha}2+PdCu\to{\alpha}1+{\alpha}2+PdCu$ at Pd/Cu = 1 Ag-Pd-Cu alloy is more effective dental alloy as ageing treatment and is suitable to isothermal ageing at $450^{\circ}C$.