• The Journal of the Petrological Society of Korea
• /
• v.14 no.3 s.41
• /
• pp.141-148
• /
• 2005

Lead isotopic compositions are analyzed from the sulfide minerals of the Yeonhwa, Janggun and Uljin deposits and from host limestone, intrusives, and basement rocks to reveal the source of Pb in these deposits. In the $^{206}Pb/^{204}Pb$ vs $^{207}Pb/^{204}Pb$ plot, Galenas from the Yeonhwa mine display relatively well defined positive linear array, similar to the Precambrian basement rocks of the Korean peninsula. A galena sample from the Uljin mine, Janggun limestone and the basement rocks also follow the variation of Yeonhwa mine. However, ore minerals from the Janggun mine, having relatively low $^{206}Pb/^{204}Pb$ values, reveal offset from such trend toward lower $^{207}Pb/^{204}Pb$ values. Considering the fact that Mesozoic igneous rocks and ores within the Gyeongsang basin display considerably lower $^{207}Pb/^{204}Pb$ values than basement rocks of the Korean peninsula, the deviation of Janggun ore minerals can be interpreted as to reflect mixing between leads from old continental crustal materials and from Mesozoic igneous rocks with more mantle signature. The lead of the Yeonhwa and Uljin mine, following trend of Precambrian basement rather well, seems to have been originated mostly from such basement. However, regarding that they occupy low $^{207}Pb/^{204}Pb$ side of the variation trend of the basement, the possibility of having some leads derived from the Mesozoic igneous rocks cannot be excluded.

• The Journal of the Petrological Society of Korea
• /
• v.19 no.3
• /
• pp.181-197
• /
• 2010

This study is for finding a geoscientific factor for clarifying the source soil of the ancient earthenware finding. The used samples were the earthenware, soil and rocks, which were collected at the Gyeongju, Gyeongsan and Haman area. The chemical and mineralogical study for the samples were carried out for understanding the change of mineralogical and chemical composition among them. The mineralogical compositions of the earthenware are different from those of the soils from the surrounding area, which suggests that the mineralogical approach for clarifying the source soil of the earthenware should be difficult. Major element compositions of the earthenware also are different from those of the surrounding soils, which suggests that the comparison of the chemical composition using the major elements might be difficult for deducing the source soil of the earthenware. However, PAAS-normalized rare earth element (REE) patterns and Nd model ages among the rock, soils and earthenware from the same sampling sites show similar characteristics one another compared to those of the major element compositions. Nd-Sr isotopic systematics among the earthenware, soils and rocks also show a close relationship. Our results suggest that REE and Nd-Sr isotope geochemistry might be more useful than the other geochemical technique in clarifying the source soils of the ancient earthenware.

• Economic and Environmental Geology
• /
• v.30 no.1
• /
• pp.25-33
• /
• 1997

The purpose of this study is to examine the feasibility of using stable isotopes as a hydrologic tracer, and to elucidate the groundwater circulation system and the source of S component dissolved in thermal water of the Chonju Jukrim thermal spring district based on the O, H and S isotopic variabilities of environmental materials including bedrock, rainwater, surface water, shallow subsurface water and thermal spring water. The ${\delta}^{18}O$ and ${\delta}D$ of subsurface waters and surface water show highly restricted range and plotted on the same meteoric water line as a ${\delta}D=8{\delta}^{18}O+19$ line, and derivate from the mean annual isotopic composition of the rain water but are analogous to those of rain waters precipitated during winter season, indicating that ground waters are originated from the meteoric water and are strongly affected by the seasonal variation of air mass. Thermal spring waters are more depleted in ${\delta}^{18}O$ and ${\delta}D$ than those of shallow ground water and surface water. It can be explained by the difference of recharge area. The hydrochemical properties of subsurface waters and surface water devide into two groups: $Ca(HCO_3)_2$ type including shallow subsurface water and surface water, and $Na(HCO_3)$ type of thermal spring waters. The ${\delta}^{34}S$ values of thermal spring water show very high positive and quitely distinct from those of shallow subsurface water and surface water that are similar to those of bed rocks, indicating that sulfate dissolved in thermal spring water has not only a terrigenic origin, but also originates partially from the foreign source containing very heavy ${\delta}^{34}S$ component such as an ancient sea water. However, the presence of $H_2S$ can not be ignore the affact of the isotopic fractionation to explaine the heavy ${\delta}^{34}S$ of thermal spring water. Overall, the Oxygen and Hydrogen stable isotopes can identify the source and the circulation system of the natural waters and the S-isotopes can provide a crucial clue on tracing the dissolved material transports in the circulation system of the natural water.

• Korean Journal of Head & Neck Oncology
• /
• v.20 no.2
• /
• pp.181-188
• /
• 2004

Background: About 3% of all cancer patients suffer from cancer of unknown primary origin. Generally, carcinoma of unknown primary (CUP) carries a grave prognosis, but primary tumor presented to the neck is exception to this. The aims of study are to determine the role of chemotherapy and to find the prognostic factors in unknown primary tumor presented to the neck. Method and Material: Eighty-four patients were diagnosed with unknown primary tumor presented to the neck between January 1996 and June 2002. Among 84 patients, 43 patients (52%) received chemotherapy, radiation or surgery were performed in 20 patients (23%), 21 patients (25%) had no treatment. Results: The response rates to chemotherapy were 87.5% in CUP only localized to the neck and 44.0% in CUP systemically involved (p=0.012). A median follow-up duration was 6.4 years and overall median survival time was 9 months. The median overall survival time of patients treated with chemotherapy were 17 months and that of patients who received surgery or radiation were 20 months (p=0.3548). The important prognostic factors were performance status and the number of involved organ. Conclusion: The prognosis of patients with CUP presented to the neck is more favorable than that of patients with CUP of other localization. The effectiveness of chemotherapy for CUP only localized to the neck was similar to that of surgery or radiation. The important prognostic factors were performance status and the number of involved organ.

• Archives of Plastic Surgery
• /
• v.35 no.6
• /
• pp.631-636
• /
• 2008

Purpose: Adipose tissue-derived stem cells(ADSC) has an osteoconductive potential and demineralized bone matrix(DBM) is an osteoinductive material. A combination of DBM and ADSC wound probably create osteoinductive properties. The purpose of this study is to determine the effect of the combination of DBM and ADSC mixture on healing of rat calvarial defect. Methods: Thirty adult male Sprague-Dawley rats were randomized into 3 groups(n=10) as 1) Control, 2) DBM alone, 3) DBM with ADSC mixture. DBM with ADSC mixture group has had a 3-day preculture of ADSC from groin fat pad. An 6 mm critical size circular calvarial defect was made in each rat. Defect was implanted with DBM alone or DBM with ADSC mixture. Control defect was left unfilled. 6 and 12 weeks after the implantation, the rats were sacrificed and the defects were evaluated by histomorphometric and radiographical studies. Results: Histomorphometric analysis revealed that DBM with ADSC mixture group showed significantly higher bone formation than DBM alone group(p<0.05). Although radiographs from DBM alone group and DBM with ADSC group revealed similar diffuse radiopaque spots dispersed throughout the defect. Densitometric analysis of calvarial defect revealed DBM with ADSC mixture group significantly higher bone formation than DBM alone(p<0.05). There was correlation of densitometry with new bone formation(Spearman's correlation of coefficient=0.804, 6 weeks, 0.802, 12 weeks). Conclusion: The DBM with ADSC mixture group showed the best healing response and the osteoinductive properties of DBM were accelerated with ADSC mixture. It will be clinically applicable that DBM and ADSC mixture in plastic and reconstructive surgery, such as alveolar cleft and congenital facial deformities that bone graft should be required.

• Proceedings of the KWS Conference
• /
• 2010.05a
• /
• pp.51-51
• /
• 2010

Recently just as in the automobile industry, shipbuilders also try to reduce material consumption and weight in order to keep operating costs as low as possible and improve the speed of production. Naturally industry is ever searching for welding techniques offering higher power, higher productivity and a better quality. Therefore it is important to have a details research based on the various welding process applied to steel and other materials, and to have the ability both to counsel interested companies and to evaluate the feasibility of implementation of this process. Submerged-arc welding (SAW) process is usually used about 20% of shipbuilding. Similar to gas metal arc welding(GMAW), SAW involves formation of an arc between a continuously-fed bare wire electrode and the work-piece. The process uses a flux to generate protective gases and slag, and to add alloying elements to the weld pool and a shielding gas is not required. Prior to welding, a thin layer of flux powder is placed on the work-piece surface. The arc moves along the joint line and as it does so, excess flux is recycled via a hopper. Remaining fused slag layers can be easily removed after welding. As the arc is completely covered by the flux layer, heat loss is extremely low. This produces a thermal efficiency as high as 60% (compared with 25% for manual metal arc). SAW process offers many advantages compared to conventional CO2 welding process. The main advantages of SAW are higher welding speed, facility of workers, less deformation and better than bead shape & strength of welded joint because there is no visible arc light, welding is spatter-free, fully-mechanized or automatic process, high travel speed, and depth of penetration and chemical composition of the deposited weld metal. However it is difficult to application of thin plate according to high heat input. So this paper has been focused on application of the field according to SAW process for thin plate in ship-structures. For this purpose, It has been decided to optimized welding condition by experiments, relationship between welding parameters and bead shapes, mechanical test such as tensile and bending. Also finite element(FE) based numerical comparison of thermal history and welding residual stress in A-grade 3.2 thickness steel of SAW been made in this study. From the result of this study, It makes substantial saving of time and manufacturing cost and raises the quality of product.

• Journal of Korean Society of Steel Construction
• /
• v.9 no.3 s.32
• /
• pp.363-375
• /
• 1997

This study encompasses the performance of static and fatigue test for the 8 large scale test specimens to clarify the fatigue behavior of coped stringer and the effect of the repair and strengthening on the damaged stringer of the floor system in steel railway bridges. For the purpose of the research, the actual stress wave for the existing bridge was measured, the basic stress range frequency histogram was made and the equivalent stress range was calculated. Using the result from the equivalent stress range made by adjusting the stress range, the static and fatigue test was carried out by identifying the previous rehabilitation and after. As the result of the static tests, it was revealed that the level of local stress under the S1 specimen test of the real equivalent stress range was similar to tensile strength of the test material, and it was consistent with the requirement of the initiation condition of the fatigue crack. Through the various rehabilitation methods to the damaged specimens, the effects of the repair and reinforcement were analyzed. According to the results of the repair of effect, bolting the high tension bolt over the stop hole was confirmed to be more adequate method than drilling only stop hole to delay the fatigue crack growth. Futhermore, in case of the stringer subjected by bending moment, the reinforcement over the upper flange side was determined to be a useful strengthening method, and the reinforcement to the web of the stringer was not appropriate to accomodate as a adequate strengthening method. Also it was confirmed that the category of the fatigue design for the coped stringer met with the category E specified on the fatigue design criteria of the Highway Standard Specification in Korea.

• Journal of the Korean Wood Science and Technology
• /
• v.33 no.6 s.134
• /
• pp.55-62
• /
• 2005

This study was conducted to evaluate the application of a bio-composite made by the addition recycled fiber board flour as filler. Recycled fiber board (high density fiber board, HDF) flour was added to polyolefin polymer low density polyethylene (LDPE) and polypropylene (PP) for the preparation of bio-composite materials. The mechanical properties and processability of the recycled HDF flour filled LDPE and recycled HDF flour filled PP bio-composites were then measured and compared to those of wood flour (WF) and rice-husk flour (RHF) filled LDPE and PP bio-composites, respectively. The tensile and impact strengths of the recycled HDF flour filled LDPE and PP bio-composites had similar mechanical properties to those of the WF and RHF filled LDPE and PP bio-composites. To measure the processability, torques of the bio-composites were also measured. The torques of the HDF flour filled LDPE and PP bio-composites were lower than those of the WF and RHF filled polyolefin (PP and LDPE) bio-composites with a filler loading of 30 wt.%. This result showed definite processability, which was not related with the distribution of the particle size of the material added. The recycled fiber board flour filled bio-composites showed applicability as substitutes for the bio-composites currently used in the bio-composites industry.

• Journal of Chest Surgery
• /
• v.38 no.5 s.250
• /
• pp.371-376
• /
• 2005

Background: Retrospective study was carried out on patients with primary spontaneous pneumothorax with the aim of determining if conventional thoracoscopic wedge resection is superior to modified transaxillary minithoracotomy with thoracoscopy in the surgical treatment. Material and Method: 160 patients, aged 14 to 35 years with primary spontaneous pneumothorax were involved in this study. Patients were assigned to two groups by surgical technique; Conventional thoracoscopic wedge resection (group A; n=80) and modified transaxillary minithoracotomy with thoracoscopy (group B; n=80). Apical pleural abrasion & talc poudrage were performed in all cases. This study evaluated the following factors: duration of operation, days of analgesics used after operation, number of no air leak on the first postoperative day, duration of indwelling chest tube, hospital stay, postoperative complications, chronic chest pain (during follow-up) and resumption of normal activity. Relapses (ipsilateral recurrence after discharge) during follow-up periods were evaluated. Result: No significant differences were found in any of the factors studied in either group. Conclusion: Conventional thoracoscopic wedge resection and modified transaxillary minithoracotomy with thoracoscopy offer similar results in the surgical treatment of primary spontaneous pneumothorax. The rate of complication is low and the level of pain is acceptable without long-term sequele. Therefore, modified transaxillary minithoracotomy with thoracoscopy method appears as a valuable alternative surgical technique.

• Journal of Chest Surgery
• /
• v.33 no.10
• /
• pp.817-822
• /
• 2000

Video assisted thoracic sympathectomy or sympathicotomy is a safe and effective therapy for the treatment of palmar hyperhidrosis with immediate symptomatic imporvement. However the degree of satisfaction may diminish with time due to cmpensatory sweating or excessive hand dryness. Therefore by comparing and assessing the degree of symptomatic improvement or compensatory sweating following sympathectomy or sympathicotomy at various levels we aim to determine the optimal level of sympathetic nerve block which will result in minimal side effects and maximal benefit. Material and Method: Among 194 patients having undergone video assisted thoracic sympathectomy or sympathicotomy between January 1996 and June 1999, 137 patients who responded to either telephone interview or questionnaire were included in the current study. The patients were divided into three groups. Group I(n=61) ; patients having undergone T2,3,4 sympathectomy group II(35) ; patients having undergone T2 sympathicotomy and group III(41) ; patients having undergone limited T2 sympathicotomy which consist of block of interganglionic neuronal fiber on the third rib. The parameters studied comprised of pre- and post-operative palmar temperature change treatment satisfaction the degree of compensatory sweating or discomfort from palmar dryness postoperative complication and changes in plantar sweating Result : There was no difference in age and sex among the groups and the mean postoperative elevation in palmar temperature was 21.59$^{\circ}C$ without any differences among the groups. Patients expressing satisfaction were 65.6%, 62.9% and 90.24% in groups I, II and III, respectively(p<0.05) Moderate to severe compensatory sweating was present in 65.6% 51.4%, and 24.39%, in group I, II, and III, respectively(p<0.05) Slight but comfortable amount of palmar humidness was expressed in decreasing order group III(41.6%) group I(24.6%) and group II(5.7%) (p<0.05) Ineffectiveness or recurrence was present in 5patients in group I(8.2%) 1 patient in group II(2.9%) and none in group III. With regards to plantar sweating decrease in sweating was expressed in 43 patients(31.4%) while similar degree of sweating in 61 patients(44.5%) and increase in sweating in another 33 patinets(24.1%) Conclusion : Limited T2 sympathicotomy resection of the lower interganglionic neuronal fiber of the second sympathetic ganglion on the third rib showed immediate effect in palmar hyperhidrosis and caused lesser compensatory sweating and hand dryness.