• Economic and Environmental Geology
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• v.22 no.3
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• pp.221-235
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• 1989

Gold-silver mineralization of the Goryeong-Waegwan area was deposited in three stages of quartz and calcite veins which fill fissures in Cretaceous sedimentary rocks of the Sindong Group. Radiometric dating indicates that mineralization is Late Cretaceous age(98 Ma) likely associated genetically with intrusion of a small biotite granite stock. Fluid inclusion and stable isotope data indicate that Au-Ag ore was deposited at temperatures between $280^{\circ}C$ and $230^{\circ}C$ from fluids with salinities between 1.7 and 8.7 equiv.wt.% NaCl. Evidence of boiling indicates pressures of <100 bars, corresponding to depths of 425 and 1,150m, respectively, assuming lithostatic and hydrostatic loads. Within ore stage I there is an apparent decrease in ${\delta}^{34}S$ values of $H_2S$ with paragenetic time, from +1.4 to -2.5 per mil. This pattern was likely achieved through progressive increases in pH and activity of oxygen accompanying boiling. Measured and calculated hydrogen and oxygen isotope values of ore-forming fluids(${\delta}D$ = -90 to -100 per mil; ${\delta}^{18}O$ = +3.9 to -11.4 per mil) indicate meteoric water dominance, approaching unex-changed meteoric water values. Au-Ag deposition is thought to be the result of cooling and dilution of a boiling fluid through mixing with less evolved meteoric waters.

• Economic and Environmental Geology
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• v.36 no.6
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• pp.511-525
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• 2003

The Okcheon Group in the southwestern part of the Okcheon Metamorphic Belt is subdivided into two distinct tectonostratigraphic units: the Boeun unit in the south and the Pibanryeong unit in the north. The Boeun unit consists of petites, psammites, carbonaceous petites, limestones and pebble-bearing quartzites. The Pibanryeong unit is composed of petites, well-sorted fine-grained psammites, carbonaceous psammites and quartzites. In order to outlining stratigraphy and depositional environments of the Okcheon Group, detailed stratigraphic sections were measured in three locations; one section(Gosan section) of the Boeun unit and two sections(Sorungjae and Hwangryeongzae sections) of the Pibanryeong unit. The Gosan section of the Boeun unit is interpreted to be deposited in the shallow marine environments, whereas the Sorungjae and Hwangryeonaiae sections of the Pibanryeong unit appear to be deposited in slope and deep basin environments. This result indicates rapid subsidence between deposition of the Boeun and Pibanryeong units in sedimentary environment. The trace of sedimentological environments in the Hwasan area was investigated by geochemical analysis of 109 metapelitic and psammitic rock samples. Distinct chemical variations of politic and psammitic rocks from the Boeun and Pibanryeong units in the study area are evident from plots of major elements and $A1_2O_3$/$SiO_2$ versus Basicity Index($Fe_2O_3{＋}MgO$)/($SiO_2{＋}K_2O{＋}Na_2O$). The rocks show a progressive chemical trend from the Boeun unit to the Pibanryeong unit on these diagrams. They in the southern sector of the Boeun unit display lower values and a comparatively wide range of $A1_2O_3$/$SiO_2$ and Basicity Index, as compared with those from the northern sector of the Boeun and Pibanryeong units. The southern sector of the Pibanryeong unit including narrow staurolite-bearing zone is characterized by values that are transitional between the Boeun and Pibanryeong units. These data, combined with depositional environment progressively deepened towards the northwest, support a half-graben model for the Okcheon basin, as proposed by Cluzel et al.(1990)

• Journal of Life Science
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• v.21 no.3
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• pp.385-392
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• 2011

The otter (Lutra lutra) in Korea is classified as a first grade endangered species and is managed under state control. We performed a phylogenetic analysis of the otter that inhabits the Changnyeong, Jinju, and Geoje areas in Gyeongsangnamdo, Korea using mtDNA and microsatellite (MS) markers. As a result of the analysis using the 676-bp D-loop sequence of mtDNA, six haplotypes were estimated from five single nucleotide polymorphisms. The genetic distance between the Jinju and Geoje areas was greater than distances within the areas, and the distance between Jinju and Geoje was especially clear. From the phylogenetic tree estimated using the Bayesian Markov chain Monte Carlo analysis by the MrBays program, two subgroups, one containing samples from Jinju and the other containing samples from the Changnyeong and Geoje areas were clearly identified. The result of a parsimonious median-joining network analysis also showed two clear subgroups, supporting the result of the phylogenetic analysis. On the other hand, in the consensus tree estimated using the genetic distances estimated from the genotypes of 13 MS markers, there were clear two subgroups, one containing samples from the Jinju, Geoje and Changnyeong areas and the other containing samples from only the Jinju area. The samples were not identically classified into each subgroup defined by mtDNA and MS markers. It could be inferred that the differential classification of samples by the two different marker systems was because of the different characteristics of the marker systems used, that is, the mtDNA was for detecting maternal lineage and the MS markers were for estimating autosomal genetic distances. Nonetheless, the results from the two marker systems showed that there has been a progressive genetic fixation according to the habitats of the otters. Further analyses using not only newly developed MS markers that will possess more analytical power but also the whole mtDNA are needed. Expansion of the phylogenetic analysis using otter samples collected from the major habitats in Korea should be helpful in scientifically and efficiently maintaining and preserving them.

• Journal of Periodontal and Implant Science
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• v.30 no.4
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• pp.851-870
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• 2000

The major goals of periodontal therapy is the functional regeneration of periodontal supporting structures already destructed by periodontal disease as well as the reduction of signs and symptoms of progressive periodontal disease. There have been many efforts to develop materials and therapeutic methods to promote periodontal wound healing. There have been increasing interest on the chitosan made by chitin. Chitin is second only to cellulose as the most abundant natural biopolymer. It is a structural component of the exoskeleton of invertebrates(e.g., shrimp, crabs, lobsters), of the cell wall of fungi, and of the cuticle of insects. Chitosan is a derivative of chitin made by deacetylation of side chains. Many experiments using chitosan in various animal models have proven its beneficial effects. The aim of this study is to evaluate the osteogenesis of chitosan on the calvarial critical size defect in Sprague Dawley rats. An 8 mm surgical defect was produced with a trephine bur in the area of the midsagittal suture. The rats were divided into two groups: Untreated control group versus experimental group with 50mg of soluble chitosan gel. The animals were sacrificed at 2, 4 and 8 weeks after surgical procedure. The specimens were examined by histologic, histomorphometric and radiodensitometric analyses. The results are as follows: 1. The length of newly formed bone in the defects was $102.91{\pm}25.46{\mu}m$, $219.46{\pm}97.81{\mu}m$ at the 2 weeks, $130.95{\pm}39.24{\mu}m$, $212.39{\pm}89.22{\mu}m$ at the 4 weeks, $181.53{\pm}76.35{\mu}m$ and $257.12{\pm}51.22{\mu}m$ at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. But, there was no statistically significant difference between the two groups. 2. The area of newly formed bone in the defects was $2962.06{\pm}1284.48{\mu}m^2$, $5194.88{\pm}1247.88{\mu}m^2$ at the 2 weeks, $5103.25{\pm}1375.88{\mu}m^2$, $7751.43{\pm}2228.20{\mu}m^2$ at the 4 weeks and $8046.20{\pm}818.99{\mu}m^2$, $15578.57{\pm}5606.55{\mu}m^2$ at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. The experimental group showed statistically significant difference to the control group at the 2 and 8 weeks. 3. The density of newly formed bone in the defects was $14.26{\pm}6.33%$, $27.91{\pm}6.65%$ at the 2 weeks, $20.06{\pm}9.07%$, $27.86{\pm}8.20%$ at the 4 weeks and $22.99{\pm}3.76%$, $32.17{\pm}6.38%$ at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. The experimental group showed statistically significant difference to the control group at the 2 and 8 weeks. These results suggest that the use of chitosan on the calvarial defects in rats has significant effect on the regeneration of bone tissue in itself

• The Journal of Natural Sciences
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• v.14 no.1
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• pp.83-121
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• 2004

This study was carried out to examine how solid the production foundation of rice in Chung-Nam Province is, and, if not, to probe alternative measures through the size of farms specializing in rice, of which direction would be a pivot of rice industry-oriented policy. The results obtained can be summarized as follows : 1. The amount of rice production in Chung-Nam Province is highest in Korea and the size of paddy field area is the second largest : This implying that the probability that rice production in Chung-Nam Province would be severely influenced by a global trend of market conditions. The number of farms specializing in rice becoming the core group of rice farming account for 7.7 percent of the total number of farm household in Korea. Average field area financial support which had been input to farm household by Government had a noticeable effect on the improvement of the policy of farm-size program. 2. Farm-size program in Chung-Nam Province established from 1980 to 2002 in creased the cultivation size of paddy field to 19,484 hectares, and this program enhanced the buying and selling of farmland and the number of farmland bargain reached 6,431 household and 16,517 hectares, respectively, in 1995-2002. Meanwhile, long-term letting and hiring of farmland appeared so active that the bargain acreage reached 6,970 hectares, and farm involved was 7,059 households, however, the farm-exchange-and-unity program did not satisfy our expectation, because the retirement farm operators reluctantly participated to sell their farms. Another reason that had delayed the bargain of farms rested on the general category of social complication attendant upon the exchange and unity operation for scattered farm. Such difficulties would work negative effects out to carry on the target of farm-size work in general. 3. The following measures were presented to propel the farm-size promotion program : a. Occupation shift project, followed by the social security program for retirement and elderly farm operators, should be promptly established and also a number of types of incentives for promoting the letting and hiring work and farm-exchange-and-unity program would also be set up. b. To establish the effective key system of rice production, all the farm operators should increase the unit area yield of rice and lower the production cost. To do so, a great deal of production teams of rice equipped with managerial techniques and capabilities need to be organized. And, also, there should be appropriate arrays of facilities including information system. This plan is desirable to be in line with a diversity of the structural implement of regional integration based on farm system building. c. To extend the size of farm and to improve farm management, we have to devise the enlargement of individual size of farm for maximized management and the utilization of farm-size grouping method. In conclusion, it can be said that the farm-size project in Chung-Nam Province which has continued since the 1980s was satisfactorily achieved. However, we still have a lot of problems to be solved to break down the barrier for attainment of the desirable farm-size operation work.. Farm-size project has fairly close relation with farm specialization in rice and, thus, the positive support for farm household including the integrated program for both retirement farmers and off-farm operators should be considered to pursue the progressive development of the farm-size program, which is key means to successful achievement of rice farming enforcement in Chung-Nam Province.

• Journal of the Korean Society of Groundwater Environment
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• v.7 no.3
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• pp.103-115
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• 2000

The formation of brown-colored precipitates is one of the serious problems frequently encountered in the development and supply of groundwater in Korea, because by it the water exceeds the drinking water standard in terms of color. taste. turbidity and dissolved iron concentration and of often results in scaling problem within the water supplying system. In groundwaters from the Pajoo area, brown precipitates are typically formed in a few hours after pumping-out. In this paper we examine the process of the brown precipitates' formation using the equilibrium thermodynamic and kinetic approaches, in order to understand the origin and geochemical pathway of the generation of turbidity in groundwater. The results of this study are used to suggest not only the proper pumping technique to minimize the formation of precipitates but also the optimal design of water treatment methods to improve the water quality. The bed-rock groundwater in the Pajoo area belongs to the Ca-$HCO_3$type that was evolved through water/rock (gneiss) interaction. Based on SEM-EDS and XRD analyses, the precipitates are identified as an amorphous, Fe-bearing oxides or hydroxides. By the use of multi-step filtration with pore sizes of 6, 4, 1, 0.45 and 0.2 $\mu\textrm{m}$, the precipitates mostly fall in the colloidal size (1 to 0.45 $\mu\textrm{m}$) but are concentrated (about 81%) in the range of 1 to 6 $\mu\textrm{m}$in teams of mass (weight) distribution. Large amounts of dissolved iron were possibly originated from dissolution of clinochlore in cataclasite which contains high amounts of Fe (up to 3 wt.%). The calculation of saturation index (using a computer code PHREEQC), as well as the examination of pH-Eh stability relations, also indicate that the final precipitates are Fe-oxy-hydroxide that is formed by the change of water chemistry (mainly, oxidation) due to the exposure to oxygen during the pumping-out of Fe(II)-bearing, reduced groundwater. After pumping-out, the groundwater shows the progressive decreases of pH, DO and alkalinity with elapsed time. However, turbidity increases and then decreases with time. The decrease of dissolved Fe concentration as a function of elapsed time after pumping-out is expressed as a regression equation Fe(II)=10.l exp(-0.0009t). The oxidation reaction due to the influx of free oxygen during the pumping and storage of groundwater results in the formation of brown precipitates, which is dependent on time, $Po_2$and pH. In order to obtain drinkable water quality, therefore, the precipitates should be removed by filtering after the stepwise storage and aeration in tanks with sufficient volume for sufficient time. Particle size distribution data also suggest that step-wise filtration would be cost-effective. To minimize the scaling within wells, the continued (if possible) pumping within the optimum pumping rate is recommended because this technique will be most effective for minimizing the mixing between deep Fe(II)-rich water and shallow $O_2$-rich water. The simultaneous pumping of shallow $O_2$-rich water in different wells is also recommended.

• Journal of Chest Surgery
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• v.37 no.9
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• pp.768-773
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• 2004

Failure of mitral valve repair sometimes may be ascribed to severe or progressive alteration of the subvalvar apparatus. The aim of this study was to evaluate the effects of new chordae formation on mitral repair. Material and Method: From March 1997 to february 1999, 26 patients underwent mitral valve repairs with new chordae formation, we compared the symptoms and echocardiographic findings checked at preoperative state, and intraoperative period, discharge, and their last OPD visit. There were 45 male, and 11 female patients, and their mean age was 51.2$\pm$43.4 years. Etiology of the lesions was degenerative (18), rheumatic (6), infective (1) and ischemic (1). Chordal lesions were caused by rupture (18), elongation (6), and a combination of two causes (2). Associated lesions included atrial septal defect (2), tricuspid insufficiency (7), aortic insufficiency(4), and a combination of previous two factors (2). The number of mean artificial chordae was 3.6$\pm$1.6. Annuloplasty was per-formed in all cases. The CPB time was 182,1$\pm$63.7 minutes and the ACC time was 133.1$\pm$45.6 minutes. Aver-age follow up period was 49.2$\pm$7.1 months. Result: There was no early death. Early reoperation was performed in bud patients, one patient received mitral valve replacement because of an abnormality of annuloplasty and ano-ther received pericardiostomy due to postoperative pericardial effusion. During the follow up of 49.2$\pm$7.1 moths, there was no late mortality. Postoperative NYHA functional class checked at last OPD visit was class I in 22 patients (88%), class II in 2 (8%), and class III in 1 (4%). Regarding the late echocardiogram MR was absent in 20 patients (78%), 1 in 4 (15%), and II in 1 (4%). The postrepair mitral valve area was 2.2$\pm$0.35 $\textrm{cm}^2$ Conclusion: This study suggests that mitral valve repair using new chordae formation provides good early and mid term survivals and functional improvement. We think that the artificial chorda formation with polytetrafluoroethylene suture might be safe and effective technique for mitral valve repair.

• Journal of the Korean Geophysical Society
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• v.7 no.3
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• pp.193-206
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• 2004

Geophysical data including chirp (3 7 kHz) subbottom profile and detailed bathymetry were obtained over three seamounts in the Ogasawara Fracture Zone (OFZ) of the western Pacific, as a part of manganese crust survey onboard R/V Onnuri in 2003. The OFZ is a 150-km-wide, 600-km-long rift zone, which separates the East Mariana and Pigafetta Basin. The OFZ is unique in that it includes many seamounts (e.g., Magellan Seamounts andseamounts on the Dutton Ridge). The sub-seafloor acoustic echoes obtained near the OFZ were classified into following types on the basis of their characteristics: types I-1(pelagic sediment with parallel or subparallel reflectors), I-2 (pelagic sediment with no internal reflectors), and III-1 (reef build-up complex) on summit; types II-1 and III-2 (basement outcrop) on flank rift zone and upper slope, respectively; type III-3 (slump) on the lower slope and embayment between the flank rift zones; types II-2 (debrite) on the base of slope and basin floor; and types II-3 (turbidite or pelagic sediment) and II-4 (turbidite) on the basin floor. The mass-wasting that produced the complex of type II-2 debrite and III-3 slump on the lower slope and basin may have been caused by (1) strong tensional stress in the OFZ which may cause the numerous fissures or basement faults and (2) complex of the faults on the summit and steep upper slope. The variations in the echo type of pelagic sediment in the summit of seamounts may be related with the changes in the depositional and/or erosional environments. Type I-2 pelagic sediment, which is characterized by a thin and intermittent coverage, was probably deposited at a sheltered area when the current was strong, whereas type I-1 pelagic deposit occurred during a stage of progressive sedimentation.

• The Korean Journal of Air & Space Law and Policy
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• v.30 no.2
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• pp.249-277
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• 2015

Regulation (EC) No 261/2004 ("Regulation") is a common rule on compensation and assistance to passengers in the event of denied boarding and of cancellation or long delay of flights. In some recent cases of European nations, passengers sued the air carrier in order to obtain monetary compensation under Article 7(1) of the Regulation. Some courts dismissed the actions on the grounds that, unlike denied boarding or cancellation of the flight, the Regulation provides no compensation in relation to delayed flights. However, Court of Justice of the European Union(CJEU) ruled that Regulation 261/2004 must be interpreted to mean that passengers whose flights are delayed have a right to compensation in cases when the loss of time is equivalent to, or is in excess of three hours - where the passengers eventually reached their final destination three hours or more later than the originally scheduled arrival time. It is true that a strict interpretation of the regulation would suggest that passengers whose flight has merely been delayed are not entitled to compensation. They should only be offered assistance in accordance with the Articles 6 and 9. Nevertheless, the Court recognized the same right to the same compensation for passengers of flights delayed by more than three hours as that explicitly provided for passengers of cancelled flights. On the one hand, the Court bases this ruling on the recitals of the Regulation, in which the legislature links the question of compensation to that of a long delay, while indicating that the Regulations seek to ensure a high level of protection for passengers regardless of whether they are denied boarding or their flight is cancelled or delayed. On the other hand, the Court interprets the relevant provisions of the Regulation in light of the general principle of equal treatment. Furthermore, the Court delivered a ruling that the loss of time inherent in a flight delay, which constitutes an inconvenience within the intention of Regulation No 261/2004 and which cannot be categorized as 'damage occasioned by delay' within the meaning of Article 19 of the Montreal Convention, cannot come within the scope of Article 29 of that convention. Consequently, under this view, the obligation under Regulation No 261/2004 intended to compensate passengers whose flights are subject to a long delay is in line with Article 29 of the Montreal Convention. Although the above interpretation of the Court can be a analogical interpretation, the progressive attitude of the Regulation and the view of Court forward to protect passengers' interest is a leading role in the area of international air passenger transportation. Hopefully, after the model of the positive support in Europe, Korea can establish a concrete rule for protecting passengers' right and interest.

• Journal of Periodontal and Implant Science
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• v.35 no.4
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• pp.1019-1037
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• 2005

The major goals of periodontal therapy are the functional regeneration of periodontal supporting structures already destructed by periodontal disease as well as the reduction of signs and symptoms of progressive periodontal disease. There have been many efforts to develop materials and therapeutic methods to promote periodontal wound healing. There have been increasing interest on the chitosan made by chtin. Chitosan is a derivative of chitin made by deacetylation of side chains. Chitosan has been widely studied as bone substitution and membrane material in periodontology. Many experiments using chitosan in various animal models have proven its beneficial effects. Tetracycline has been considered for use in the treatment of chronic periodontal disease and gingivitis. The aim of this study is to evlauate the osteogenesis of tetracycline blended chitosan membranes on the calvarial critical size defect in Sprague Dawley rats. An 8mm surgical defect was produced with a trephine bur in the area of the midsagittal suture. The rats were divided into five groups: Untreated control group versus four experimental group. Four types of membranes were made and comparative study was been done. Two types of non-woven membranes were made by immersing non-woven chitosan into either the tetracycline solution or chitosan-tetracycline solution. Other two types of sponge membranes were fabricated by immersing chitosan sponge into the tetracycline solution, and subsequent freeze-drying. The animals were sacrificed at 2 and 8 weeks after surgical procedure. The specimens were examined by histologic analyses. The results are as follows: 1. Clinically the use of tetracycline blended chitosan membrane showed great healing capacity. 2. The new bone formations of all the experimental group, non-woven and sponge type membranes were greater than those of control group. But, there was no significant difference between the experimental groups. 3. Resorption of chitosan membranes were not shown in any groups at 2 weeks and 8 weeks. These results suggest that the use of tetracycline blended chitosan membrane on the calvarial defects in rats has significant effect on the regeneration of bone tissue in itself. And it implicate that tetracycline blended chitosan membrane might be useful for guided tissue regeneration.