• Economic and Environmental Geology
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• v.2 no.1
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• pp.13-33
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• 1969

The Mulkum mine, located in Mulkum-myon, Yangsan-Kun, Kyeongsang Province, is one of the biggest iron mine in Korea. The geology of this mine and its vicinity consists of Chusan andesitic rocks and Datae-dong andesite porphyry of the Kyeongsang System which were intruded by biotite granite widely distributed near the vicinity of Mulkum-ni. The ore deposits, embedded in Dotae-dong andesite porphyry, are fissure-filling vein type in origin. Up to present ore bodies of Main vein, No. 2 vein, Eastern No. 1, 2 vein and Western No. 1 vein are exploited. Generally the veins strike N 10-25 E and dip to 60-90 SE. The proved length of vein is more than 500 meters and its depth 150 meters in Main vein with 3-4 meters of thickness in average. Ore minerals are mainly magnetite and locally associated with small amounts of hematite, sphecularite and chalcopyrite. Gangue minerals are quartz, epidote, chlorite, pyroxene, and garnet, etc. The modes of occurrence of vein are as follow; 1. Branching and parallel vein patterns are observed around main shaft in -1 level. 2. Multiple cymoid loops and subrectangular vein patterns are observed around main shaft in -2 level. 2. Single vein patterns are observed in -3 and -5 level. The ore-shoots plunge northeasterly about 20-30 degrees. In conclusion, the tectonically fractured zone belongs to the poorly mineralized zone and shoots are formed as single vein type. The general trends of one-shoots must be applied the prospecting of the deep-seated ore body in the deposits.

• Textile Coloration and Finishing
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• v.30 no.3
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• pp.190-198
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• 2018

We fabricated high transmission and high scattering poly(ethylene-co-vinyl acetate)(EVA) films embedding $SiO_2$ nanoparticles to improve outcoupling efficiency in organic display. The 800nm diameter $SiO_2$ nanoparticles aggregated and formed $1.56{\mu}m$ (with ${\pm}0.853{\mu}m$ standard deviation) diameter microparticles in EVA. The total transmission of scattering film was 83.3% on Polyethylene terephthalate(PET), which was higher than reference 82.8% PET substrate. The diffuse transmission and haze of the $SiO_2$ embedded EVA film were 76.1% and 91.4%, respectively. The optimized condition was 1:1 weight ratio of $SiO_2$ nanoparticles to EVA in Tetrahydrofuran(THF) solution. When the ratio of $SiO_2$ was larger than 1, the total transmission decreased by the increase in backscattering of light due to high scattering. With the optimized condition, we could succeed to fabricate a large scale film(35m in length) with a roll-to-roll process.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.547-554
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• 2013

This study was intended to estimate the bond strength of steel fiber in UHPFRC through pullout test. The pullout test was carried out with the double-sided pullout specimens with multiple fibers. First, the effect of fiber density on the bond strength was investigated, and the experimental result presented that the density range considered in this study was proved not to produce fiber-to-fiber interaction. The bond strength was estimated from several methods, which are based on the pullout load or energy at peak load, and the total energy absorbed until fibers are pulled out completely. the estimated bond strength obtained from the total energy was shown to be under the influence of the embedded length of fiber. the bond strengths obtained from peak load condition was 6.64 MPa in average, which had little difference compared to 6.46 MPa calculated by peak load only. Considering simplicity of test and analysis, it may be no matter to estimate the bond strength from peak load in pullout test.

• Journal of the Korean Geotechnical Society
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• v.21 no.2
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• pp.47-55
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• 2005

This paper describes the results for a numerical analysis of'single piles and pile oops in clayey soils subjected to monotonous lateral loading using the ABAQUS finite element software. The investigated variables in this study include free head and embedded capped single piles, pile diameter (1.0 m, 0.5 m), pile length (7.0 m, 10.0 m), and pile groups. The 1$\times$3 pile group was selected to investigate the individual pile and group lateral resistance, the distribution of the resistance among the piles, the effects of lateral stresses in front of and on the sides of the piles, and the effect of a cap on the lateral resistance of the leading pile. The soil was modeled using Cam-clay constitutive relationship and the pile was considered as a elastic circular concrete pile. The results show that the size of the cap influences lateral capacity of sin pile. The results also show in pile groups, the pile-soil-pile interaction and the cap effect the resistance in the leading pile, and the p-multiplier for the leading pile of greater than 1.0 was able to be obtained.

• Journal of the Korean Geotechnical Society
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• v.30 no.9
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• pp.5-17
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• 2014

A series of model tests were conducted in order to observe the failure surface generated around a diaphragm wall embedded in ground with high groundwater table. Images of the soil deformation around the model wall were captured during the test. The configuration of the failure surface in soil around the model wall could be obtained from analyzing the image of the soil deformation. Based on the configuration of the failure surface observed in the model test, an analytical approach was proposed to predict the uplift capacity of a diaphragm wall installed in ground. The analytical approach considers not only the wall properties such as length, thickness and surface roughness of diaphragm walls but also the soil strength properties such as the internal friction angle and the cohesion of soil. The predicted uplift capacity of a diaphragm wall shows a good agreement with the experimental one measured in the model test.

• Journal of the Korean Geotechnical Society
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• v.36 no.2
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• pp.29-42
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• 2020

In this study, centrifuge tests were performed to investigate the effect of the lateral load-moment combination on the p-y curves for 7 m-diameter monopiles installed in sand for offshore wind turbine. For the objectives, a centrifuge testing system was developed and tests were conducted at an acceleration of 68.83 g using well-instrumented model monopiles under two different lateral load-moment combinations simulated by different loading heights: 1 and 5 times monopile diameter from the ground surface. The sand was prepared as medium loose sand. Based on the centrifuge test results, the experimental p-y curves were evaluated and compared with previous literatures including API codes. The experimental results reveal that the p-y curves were little influenced by the combination of lateral load and moment. It was also found that the embedded length affects p-y curves.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.1
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• pp.57-64
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• 2016

Background: Tobacco smoking is considered a risk factor for cervical cancer development due to the presence of tobacco based carcinogenic metabolites in cervical cells of female smokers. In this study, we investigated the role of the T3801C (MspI) polymorphism of CYP1A1, a gene encoding an enzyme necessary for the initiation of tobacco based carcinogen metabolism, on cervical cancer risk. The T to C substitution may alter CYP1A1 activities, potentially elevating cervical cancer risk. Since results of gene-disease association studies vary according to the study population, the multi-ethnic population of Malaysia provides an excellent representative cohort for identifying and comparing the cervical cancer risk among the 3 major ethnics in Southeast Asia in relation to CYP1A1 MspI polymorphism. Materials and Methods: A total of 195 Thin Prep Pap smear samples from HPV negative and cancer free females were randomly selected as controls while 106 formalin fixed paraffin embedded samples from females with invasive cervical cancer were randomly selected for the cases group. The polymorphisms were identified using restriction fragment length polymorphism (RFLP) PCR. Results: We found no significant associations between CYP1A1 MspI polymorphism and cervical cancer in the general Malaysian female population. However, upon ethnic stratification, the variant C/C genotype was significantly associated with a 4.66-fold increase in cervical cancer risk in Malay females (95% CI= 1.21-17.9; p=0.03). No significant association was observed in the Chinese and Indian females. Additionally, there were no significant associations in the dominant model and allele frequency model analysis in both the general and ethnically stratified female population of Malaysia. Conclusions: Our findings suggest that the C/C genotype of CYP1A1 MspI polymorphism is associated with the development of cervical carcinoma in the Malay females of Malaysia.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.4
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• pp.487-497
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• 2005

Purpose: Resonance frequency analysis (RFA) , a non-invasive technique for the clinical measurement of implant stability, was investigated. Peri-implant bony defect may contribute to implant failure. This in vitro study evaluated the resonance frequencies according to various bony defects and determined whether the directional bone defect can affect the value of frequency analysis. Material and Method: Fifteen 3.75 mm in diameter and 10 mm in length, machined self-tapping implant future were used. Twelve types of bone defects that have different horizontal and vertical dimensions were simulated. Embedded implants were attached to the dental surveyor. Then, the transducer was connected with the implant fixture and the ISQ value was measured at four different directions. Two-way analysis of variance and post hoc $Sch\`{e}ffe'$ test were performed at the 95% significance level. Results: The control group showed the highest ISQ value and 5 thread-$360^{\circ}$ group had the lowest one. As the vertical exposure of implants in each angle was increased, the ISQ value was decreased. Although the horizontal exposure in each thread was increased, the ISQ value was not significantly decreased. Conclusion : Although the simulated defect type was different from each other, the ISQ value was similar among groups.

• Restorative Dentistry and Endodontics
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• v.14 no.1
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• pp.71-84
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• 1989

The purpose of this study was to evaluate the effect of tricalcium phosphate and Vitapex on the dogs' periapical tissues. Twenty mandibular premolars from 5 healthy dogs were used for this study. After the animals were anesthetized intramuscularly, pulp chambers were open and pulp tissue was extirpated with a barbed broach and H-file. Then the working length of the root canal was measured with H-file and pulp tissue was completely removed. Before the actual canal filling, the root canals of twenty teeth have been experimentally infected with opening the pulp chamber for 5 weeks. Periapical radiographs of the experimental teeth were taken to monitor the periapical pathological condition. Each root apex of 20 premolars was perforated with engine reamer and the root canals were enlarged with No. 30-60 H-files. They were divided into treated as follows. Control group: The root canal was filled with gutta-percha. Experimental group 1: The canal was dried with sterile paper points and mixture of tricalcium phosphate and physiological saline was overfilled beyond the root apex with a lentulo spiral. Then the root canal was filled gutta-percha and lateral condensation and the pulp chamber was filled with Caviton. Experimental group 2: The root canals were overfilled with Vitapex and were treated in the same manner as those in experimental group 1 At 1,2,3, and 8 weeks after experiment, the periapical tissues including the alveolar bone were fixed with 10% formalin solution for I week and decalcified with Plank-Rycho solution for 5 weeks. The specimens were embedded in paraffin and serial sections were cut into a thickness of 6 ${\mu}m$ at the plane of the root apex. Hematoxyline-eosin and Masson's trichrome stain were made for the histo-pathological examinations. The results were as follows: 1. Ingrowth of collagen fiber was observed from 1 week in control group and experimental groups. 2. The rate of bone formation of experimental group 1 was accelerated more than that of experimental group 2. 3. Resorption of cementum was seen in control group, but apposition of cementum was seen in experimental groups.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.4
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• pp.793-800
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• 1997

Periotest(Siemens, Germany) has been used to test mobility of the implants clinically, however the effects of target materials and connection methods on the PTVs(Periotest Values) have not been evaluated. Periotest has been regarded as a reliable and objective tool to test implant and natural teeth mobility clinically, however this instrument showed different PTVs under various test conditions. This in vitro study was designed to compare PTVs of different veneering materials and prosthodontic designs (single and bridge restorations). To compare the effects of veneering materials on PTVs, 1 mm thickness of five different testing materials (porcelain, type III gold alloy, pure titanium, composite resin, acrylic resin) were placed on the resin block. Three full length of 13 mm Mark II implant fixtures were embedded into autopolymerizing resin block to fabricate single and bridge restorations. To evaluate effects of the connection method in single restorations, PTVs of screw retained(UCLA type) and cementation type(Cera-One system) were compared. Finally, to test reliability of PTVs of the final restorations, screw retained three unit short span PFM bridges were fabricated on the standard and Estheti-Cone abutments. All testing components were tightened with torque controller and PTVs of all specimens were measured 15 times for statistical analysis with SAS program. Following conclusions were made within the limit of this in vitro study. 1. PTVs of type III gold alloy, grade II titanium, composite resin veneering materials showed no significant differences, however acrylic resin and porcelain showed significant differences (P<0.05). 2. Single tooth restorations showed consistent PTVs as long as proper torque force was applied. 3. PTVs of bridge type prostheses was inconsistent regardless of abutment types. 4. PTVs of the prostheses showed higher scores and standard deviations than those of abutments regardless types of connection (P<0.05).