• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.328-333
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• 1996

Concrete can be defective for several reasons, including an inadequate design, material selection of workmanship, failure to appreciate the hazards associated with prevailing enviromental conditions. Concrete can also deteriorate or be damaged in use. Thus, it is necessary to evaluate the safety of existing concrete strucutres. On the basis of these reasons, they must be performed for repair or rehabilitation. Presently, strengthening methods of R/C structure used in Korea, are an enlargement of concrete member, strengthening with steel plate or CFRP on the R/C structure. It has been widely estabilished that strengthening effect of CFRP is superior to steel plate in terms of it's lighter unit weight and higher tensile strength. But there are no construction results of CFRP on the civil R/C structure in Korea. The strengthening design technique with CFRP, it's const겨ction, and it's strengthening effect for deteriorated R/C rahmen bridge is introduced in this paper.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2002.03a
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• pp.20-21
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• 2002

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.2 no.2
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• pp.53-61
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• 2009

Purpose: This study was designed to evaluate the clinical usefulness of serial ultrasonography (USG) after arthroscopic rotator cuff repair and to assess the re-tear rate and the re-tear time according to the tear sizes and the repair method. Materials and Methods: Between January 2008 and June 2008, 52 patients were treated with arthroscopic rotator cuff repair, Of the 52 patients, 29 patients that had undergone more than six months follow-up underwent preoperative USG examinations and subsequent arthroscopic examinations. MRI and USG findings were compared with intraoperative results of arthroscopic examinations. The postoperative integrity of the rotator cuff was observed using serial USG examination performed postoperatively at two weeks, six weeks, three months, and six months. Results: Small to medium rotator cuff tear were identified in 10 patients where the double pulley suture bridge (DPSB) technique was performed; the re-tear rate was 20%. For 19 patients with large to massive rotator cuff tears, the re-tear rates was 100% for six patients who had undergone tendon to tendon (TT) repair, the re-tear rate was 50% for two patients who had undergone tendon to tendon and bone to tendon (TTBT) repair and the re-tear rate was 55% for11 patients where the DPSB technique was performed. Re-tear rates according to follow-up periods were 7% from two to six weeks, 66% from six weeks to three months and 27% from three to six months postoperatively. Conclusion: Serial USG examinations after arthroscopic rotator cuff repair were useful to assess the re-tear rate and the re-tear time. In addition, USG examination were useful for treatment planning during postoperative rehabilitation.

• Journal of the Korean Arthroscopy Society
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• v.12 no.2
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• pp.75-81
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• 2008

견관절의 안정요소 중 정적 안정요소는 관절와 상완 연골 인대 복합체나 관절 일치성 등으로서 재활 과정 중 신장 운동에 관여하며, 회전근 개 근육과 각 관절 사이의 운동 조화 등으로 이루어진 동적 안정요소는 근력 강화 운동으로 재활이 이루어진다. 견관절 불안정성에 대한 수술 후 재활은 복원된 조직을 보호하면서 동시에 주위 조직과의 유착을 방지하고 관절 운동 범위를 향상하기 위해 통증을 유발하지 않는 범위 내에서 부드러운 수동 관절 운동을 먼저 실시한다. 능동적 관절운동은 수술한 조직이 치유될 충분한 시간이 경과되었거나 환자가 통증없이 독립적인 견관절 운동이 가능할 때 실시한다. 견갑와 상완 관절뿐만 아니라 견갑 흉곽 운동과 견갑골 부착 근육에 대한 재활이 제대로 이루어져야 수술 후 만족할 만한 결과를 얻을 수 있다. 끝으로 본문에 상술한 모든 재활 프로그램은 환자의 개개인의 특성에 맞춰 운동 내용과 시기를 조정하여 개별화해야 효과적인 재활이 이루어질 수 있다.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.597-600
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• 1999

Recitly, the use of sea-sand is increasing in the construction due to the rapid reduction of river-sand. In that case, one of the major problem is that a sand salt in sea-sand induce the corrosion of embedded reinforcing bar in concrete. In addition, the deterioration of concrete quality arises a social problem in the durability of reinforced concrete. This research is aimed at providing the data for the control of design method of repair and rehabilitation in the reinforced concrete structure by means of the evaluation of structural performance due to corrosion.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.2
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• pp.199-204
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• 2001

Recently, strengthening of structural members by adhesion of steel plate or fiber sheets is generally used. Particularly, the Carbon Fiber Sheets (CFS) is widely used. Rut, the strengthening effect of the CFS is not clearly define yet. Therefore, this paper is designed to evaluate the effectiveness of CFS methods by analyzing previous studies in statistics. According to the results, the maximum load carrying capacity is increased up to 0.16 times when the reinforced concrete beams were strengthened by CFS which is standard specimens. The number of sheets made some effect on the strength while, the other parameters influenced the ductile capacity.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.3
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• pp.211-220
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• 2020

When domestic sewage and rainwater runoff are discharged into a single sewer pipe, it is called a "combined sewer system." The sewage design standards in Korea specify the flow velocity based only on the volume of rainfall; therefore, sedimentation occurs on non-rainy days owing to the reduced flow rate and velocity. This sedimentation reduces the discharge capacity, causes unpleasant odors, and exacerbates the problem of combined sewer overflow concentration. To address this problem, the amount of sewage on non-rainy days, not just the volume of rainfall, should also be considered. There are various theories on sedimentation in sewer movement. This study introduces a self-cleansing velocity based on tractive force theory. By applying a self-cleansing velocity equivalent to the critical shear stress of a sand particle, sedimentation can be reduced on non-rainy days. The amount of sewage changes according to the water use pattern of citizens. The design hourly maximum wastewater flow was considered as a representative value, and the velocity of this flow should be more than the self-cleansing velocity. This design method requires a steeper gradient than existing design criteria. Therefore, the existing sewer pipelines need to be improved and repaired accordingly. In this study, five types of improvement and repair methods that can maximize the use of existing pipelines and minimize the depth of excavation are proposed. The key technologies utilized are trenchless sewer rehabilitation and complex cross-section pipes. Trenchless sewer rehabilitation is a popular sewage repair method. However, it is complex because the cross-section pipes do not have a universal design and require continuous research and development. In an old metropolis with a combined sewer system, it is difficult to carry out excavation work; hence, the methods presented in this study may be useful in the future.

• Journal of the Korea Concrete Institute
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• v.17 no.2 s.86
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• pp.171-177
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• 2005

Even though the cost associated with the repair and rehabilitation of existing structures are rapidly increasing, vast number of the repaired and rehabilitated structures do not function properly as expected during their remaining service lives. This paper focused on the flexural behavior of reinforced concrete slabs repaired and reinforced by PS strand and polymer mortar in the tension face. The slabs have the size of 700${\times}120{\times}$2200 m and 700${\times}120{\times}$1300 mm. Variables of experiment were space of strengthening, chipping, the number of strand, the kind of mortar in this experimental study. Attention is concentrated upon overall bending capacity, deflection, ductility and failure mode of repaired and reinforced slabs. Test results show that deflection of repaired and reinforced slabs reduced to approximately $40 \%$ comparison to standard slabs. Boundary cracking of chipping slab started ultimate load afterward. Concrete-mortar interface cracked 64.5 kN in repaired slab with AP mortar and 36.0 kN in repaired slab with general polymer mortar. Reinforcement effect increased with reducing space of strand. Also, Reinforcement effects are more by strand than by polymer mortar.

• The Journal of Korean Obstetrics and Gynecology
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• v.21 no.1
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• pp.257-266
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• 2008

Purpose: These experiments were undertaken to evaluate the effect of Onpoeum on ovarian functions and differential gene expressions related with cell viabilities caspase-3, MAPK and MPG in female mice. Methods: We administered the Onpoeum to 6-week-old female ICR mice for 4, 8, or 12 days. With different concentration of Onpoeum, the female mice were injected PMSG and hCG for ovarian hyperstimulation. The mice divided into 3 different groups for each experiment. We chose the Caspase-3 for cell apoptosis, MAPK and MPG genes for cell viability and DNA repair. Results: In case of 4, 8, 12 day of Onpoeum, we were examined the mean number of total ovulated oocytes and the number of morphologically normal oocytes. We were also examined the embryonic developmental competence in vitro. In addition we were examined the differential expression of cell apoptosis, viability and DNA repair related genes, Caspase-3, MAPK and MPG according to concentration and duration of Onpoeum. From these results showed that the administration of Onpoeum played a role of prevention of cell apoptosis and DNA damages and also increased cell proliferation resulted in ovarian functions. Conclusions: It is suggested that the medication of Onpoeum may have beneficial effect on reproductive functions of female mice via prevention of cell apoptosis and DNA damaging and promotion of cell proliferation.

• Journal of the Korea Concrete Institute
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• v.16 no.5 s.83
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• pp.651-657
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• 2004

The effects of polymer-cement ratio, antifoamer content and shrinkage-reducing agent content on the air content, setting time, drying shrinkage and strength of high-fluidity polymer-modified mortars using redispersible polymer powder are examined. As a result, the air content of the polymer-modified mortars using redispersible polymer powder tends to decrease nth increasing polymer-cement ratio and antifoamer content. Regardless of the antifoamer content, the setting time of the polymer-modified mortars using redispersible polymer powder tends to delayed with increasing polymer-cement ratio. Irrespective of the antifoamer content, the drying shrinkage of the polymer-modified mortars using redispersible polymer powder tend to decrease with increasing polymer-cement ratio and shrinkage-reducing agent content. Regardless of the antifoamer content, the flexural and tensile strengths of the polymer-modified mortars using redispersible polymer powder tends to increase with increasing polymer-cement ratio, and tend to decrease with increasing shrinkage-reducing agent content. However, the compressive strength of the polymer-modified mortars using redispersible polymer powder decreases with increasing polymer-cement ratio and shrinkage-reducing agent content.