• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.349-354
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• 2023

This study wa s conducted a s pa rt of ma ximizing the use of ca rbon dioxide by a pplying CCU(Ca rbon Ca pture, Utiliza tion) a mong technologies for reducing CO₂ in the cement industry. In a carbon dioxide curing environment, changes in carbonation depth and changes in basic physical properties by age due to the mixing of carbonation reaction accelerators were usually targeted at Portland cement paste. In addition, in order to check the fixed amount of CO₂ in the concrete field, a thermal analysis method was applied to evaluate CaCO₃ decarbonization at high temperatures. As a result of the evaluation, it was confirmed that the carbonation depth in the cured body significantly increased due to the incorporation of CRA in the carbonation depth diffusion performance. In addition, it was confirmed that the weight reduction rate increased by 23.8 % and 40.77 %, respectively, compared to Plain, in the order of curing conditions for constant temperature and humidity and curing conditions for carbonation chambers, so it was confirmed that the amount of excellent CaCO₃ produced by the addition of CRA increased as the concentration of CO₂ increased.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.2
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• pp.180-186
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• 2014

One or two mesiodens are mostly common to the clinician. However, three mesiodens is rarely found and can cause complications such as orthodontic problems or interruptions of the adjacent teeth with more than 1 or 2 mesiodens. Many factors cause irregularities in the permanent dentition. Mesiodens, especially in the anterior maxilla, can disturb the eruption of adjacent permanent teeth and cause diastemas, ectopic eruptions, root resorption, or the formation of dentigerous cysts. The early diagnosis of mesiodens is important for preventing such complications, and the timing of intervention should be based on their location and number. Periodic checkups and improved diagnostic devices make it easy to find mesiodens and associated complications. In this case, 3 supernumerary teeth in the maxillary anterior region were affecting the eruption of the adjacent permanent incisors. To minimize complications and preserve the deciduous teeth, the three supernumerary teeth were extracted in 2 steps. Since cone-beam computed tomography was not available, a brace wire was used to measure the depth of the mesiodens.

• Asian Journal of Turfgrass Science
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• v.16 no.1
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• pp.19-30
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• 2002

This study was conducted to investigated the effects of rubber chips from used tires on sports turf ground as soil conditioner to improve soil physical properties. The release of heavy metal ions was detected to check the soil contamination by incorporation of recycled rubber chips with topsoil. The effects of the chips were also evaluated as topdressing material to improve surface resilience. The rate of rubber chips showed a positive relationship with soil temperature increasement. Incorporation of rubber chips increased soil temperature on surface at 2.5 cm-depth. The rates of rubber chip showed a negative relationship with ground cover rate of turfgrass in early growth season. However, after 20 weeks, treatment of 10% rubber chips at 2.5 cm-depth showed a prominent cover rate of 70% which was not significantly different with untreated control. Incorporation of rubber chips within topsoil seemed to reduce soil compaction, but the effects was not prominent on physical properties. Rubber chips did not affect chemical properties and heavy metal contamination to soil environment. Rubber chips improved resilience of the compacted ground surface as topdressing material, this effect was prominent when aerification practise was preceded.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.197-200
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• 2008

The RC corbels with the ratio of shear span-to-effective depth less than 1 are commonly used to transfer loads from beams to columns. The ultimate strengths and structural behaviors of RC corbels are controlled by the shear span-to-effective depth ratio, strength of concrete, shape and quantity of the reinforcement, and geometry of corbels. In this study, a simple indeterminate strut-tie model reflecting all characteristics of the ultimate strengths and complicated structural behaviors is presented for the design of RC corbels. In addition, a load distribution ratio, defined as a magnitude of load transferred by a horizontal truss mechanism, is proposed to help structural designers perform the design of RC corbels by using the strut-tie model approaches of current design codes. The ultimate strengths of 30 RC corbels tested to failure are evaluated by using the ACI 318-05's strut-tie model code for the validity check of the proposed indeterminate strut-tie model and load distribution ratio.

• Journal of the Korean Geotechnical Society
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• v.19 no.1
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• pp.21-29
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• 2003

In this study, practical guidelines to check the possibility of some lateral movement of piled abutment were investigated. In these tests, both the depth of soft clay and the rate of embankment construction are chosen to examine the effect on lateral soil movements. The depth of soft clay layer varies from 5.2 m to 11.6 m, and the rate of embankment construction has two types : staged construction(1m/30days, 1m/15days) and instant construction. Various measuring instruments such as LVDTs, strain gauges, pressure cells, and pore pressure transducers are installed in designed positions in ordo. to clarify the soil - pile interaction and the short and long term behavior f3. piled bridge abutments adjacent to surcharge loads. The validity of the proposed guidelines by centrifuge test was compared with the observed performance by lateral movement index, F(Japan Highway Public Corporation) and modified I index(Korea Highway Corporation). Based on the results obtained, the critical values off and modified I, as a practical guidelines, are proposed as 0.03 and 2.0, respectively.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.1
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• pp.73-81
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• 1991

The purpose of this study was to analyze the position of mandibular condyle on the submentovertex radiograph, thereafter to evaluate the usefulness of submentovertex radiograph in diagnosis of temporomandibular joint dysfunction, and to check the best method of tomographic techniques. Submentovertex radiographs which were taken in 75 temporomandibular joint dysfunction patients and 75 normal persons were used as the sample for this study. The obtained results were as follows: The submentovertex radiograph was a improper method in diagnosis of temporomandibular joint dysfunction and discrimination of affected side. The selective tomography was a better method than any other tomographic techniques in diagnosis of temporomandibular joint dysfunction.

• The Journal of Internal Korean Medicine
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• v.41 no.1
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• pp.14-28
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• 2020

Objectives: The aim of this study was to analyze consumer experience with Digestive Enzymes, a digestive enzyme product that includes medicinal herbs (Multi-Zyme^®). The goal was to provide basic data on improvements and marketability of future digestive enzyme products containing medicinal herbs. Methods: Qualitative research was conducted to explore the current participants' experience. In-depth interviews with a semi-structured interview guide were conducted to investigate the experience and perception of the participants. The participants were recruited using snowball sampling and purposive sampling, and a qualitative content analysis method was adopted. Credibility was ensured by adopting a member check, triangulation, and peer debriefing method. Results: In-depth interviews were completed with a total of 8 participants. The collected data were classified into 16 codes and then further divided into the following seven categories: direct buying, indirect buying, effects, questions, recommendations, positive perception, and negative perception. The categories were grouped into three themes: 'Experience of purchasing existing health foods', 'Experience of taking Multi-Zyme', and 'Opinions on selling Multi-Zyme at Korean medicine clinics'. Conclusion: The participants experienced effect of the Multi-Zyme^® and were willing to recommend it around. However, the Korean medicine doctors need to inform consumers about the dose and duration when taking Multi-Zyme^® to prevent abuse. Some consumers may trust Multi-Zyme^® sales from Korean medicine clinics, but some held opinions that those sales were not trustworthy, so promotion and improvement are needed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.4
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• pp.389-395
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• 2016

Objectives: Acute methanol poisonings known to be typical occupational diseases occurring in developing countries broke out in sub-contract manufacturers in the early 2016. The present paper attempted to identify underlying causes which hide under apparent findings, and suggest alternative policies to prevent recurrence of similar intoxication Methods: We evaluated occupational health and safety characteristics of workers in micro-enterprises similar to workplaces with methanol poisoning by in depth-interview of employers, workers, and labor inspectors, and literature review. Results: The common findings of workplaces with methanol poisoning were addressed; First, the victims were illegal agency workers. Second, the workplaces were sub-contract micro-manufacturers with less than 5 employees. Investigators found that local ventilations did not work, while most of workers did not wear any proper personal respiratory protective equipment in the workplace. In addition, periodic environmental monitoring and medical check-ups were not done. However, these apparent findings do not appear to be root causes of methanol poisoning. Our in depth-analysis clarified a root cause; micro-enterprises with less than 5 employees are exempted with essential regulations of OSH Act, and employers do not know about OSH Act. Conclusions: We suggest occupational health policies to prevent recurrence of similar intoxication; First, government should introduce programs so that all employers should know about employers' responsibilities in OSH Act from the start of business. Second, even manufacturers with less than 5 employees should not be exempted with essential regulations of OSH Act. Finally, employers should take responsibilities for health and safety of all the workers including agency workers working in workplaces.

• Journal of the Korean Geotechnical Society
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• v.18 no.3
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• pp.43-50
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• 2002

This paper describes a simplified numerical procedure for analyzing the response of bridge pier foundations due to riverbed scouring. A computationally efficient algorithm to analyze the behavior of a pile group is proposed by considering soil-pile, pile-cap, and pile-fluid interactions. The complex phenomenon of the pile-soil interaction is modeled by discrete nonlinear soil springs (p-y, t-z and q-z curves). The pile-cap interaction is considered by geometric configuration of the piles in a group and connectivity conditions between piles and the cap. The pile-fluid interaction is incorporated into the procedure by reducing the stiffness of the soil-pile reactions as a result of nonlinearity and degradation of the soil stiffness with river bridge scouring. Through the numerical study, it is shown that the maximum bending moment increases with increasing scour depth. Thus it is desirable to check the stability elf pile groups based on soil-pile and pile-cap interactions by considering scouring depth in the riverbed.

• Journal of Periodontal and Implant Science
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• v.38 no.3
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• pp.437-444
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• 2008

Purpose: A number of techniques and materials have been used for periodontal regeneration and bone graft procedures with guided tissue regeneration(GTR) have been suggested as alternatives to osseous surgery in the management of local infra-bony defects. However, the long-term stability and treatment outcome following bone graft procedure of infra-bony defects is poorly documented. The purpose of this study was to assess radiographic change in infra-bony defects over 2 years after bone graft procedures with various graft materials. Material and Methods: Patients attending the department of periodontics of Kyungpook National University Hospital were studied. Patients showed clinical and radiographic evidence of infra-bony defect(s). 44 sites of 34 patients aged 31 to 69 (mean age 48.3) were treated by bone graft procedure with a bone graft material. Baseline and 2-year follow-up radiographs were collected and evaluated for this study. Radiographic assessment includes a bone fill, bone crest change, defect resolution, and % of defect resolution. Pre- and post-treatment differences between variables (maxilla and mandible, defect depth, defect angle, bone graft materials) using the paired t-test were examined. Result: We observed $1.15{\pm}1.95\;mm$ of bone fill, $0.40{\pm}1.19\;mm$ of crestal resorption, $1.55{\pm}1.77\;mm$ of defect resolution, and $40{\pm}44%$ of percentage of defect resolution. Deeper initial defect depth, narrower initial defect angle showed significantly greater bone fill, defect resolution, and % of defect resolution. But no significant difference was observed in graft sites and graft materials. Conclusion: If good oral hygiene maintenance and periodic recall check of patients is assured, bone graft procedure using various graft materials is one of the appropriate treatment modality for regenerative therapy of infra-bony defects.