• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.865-868
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• 2008

As a part of a series of study, this study reviewed the fire proof characteristics of high performance concrete RC column members using non-stripping form that accompanied metal lath lateral confinement to prevent spalling of high performance concrete which is increasingly used recently, and the results are as follows. Flow and air amount both satisfied target range, and compressive strength, over 80MPa at age 28 days, showed high strength range. As for spalling characteristics, in the case of plain in which no fiber is mixed, severe spalling occurred, and in the case of 0.05% nylon("NY" hereinafter)+polypropylene("PP" hereinafter) fiber mixture, only surface area experienced partial spalling. Regarding non-stripping form changes, both non-stripping 25-20 and non-stripping 50-20 experienced spalling at finish material area, and non-stripping 50-20 showed better spalling proof performance than non-stripping 25-20. In the case of non-stripping 50-40, spalling was prevented, and while mass reduction rate was less than 10%, its temperature hysteresis showed the most excellent fire proof performance with base metal surface area maximum temperature $376.1^{\circ}C$.

• Earthquakes and Structures
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• v.9 no.3
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• pp.603-623
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• 2015

The scale and nature of the recent earthquakes in the world and the related earthquake disaster index coerce the concerned community to become anxious about it. Therefore, it is crucial that seismic lateral load effect will be appropriately considered in structural design. Application of seismic isolation system stands as a consistent alternative against this hazard. The objective of the study is to evaluate the structural and economic feasibility of reinforced concrete (RC) buildings with base isolation located in medium risk seismic region. Linear and nonlinear dynamic analyses as well as linear static analysis under site-specific bi-directional seismic excitation have been carried out for both fixed based (FB) and base isolated (BI) buildings in the present study. The superstructure and base of buildings are modeled in a 3D finite element model by consistent mass approach having six degrees of freedom at each node. The floor slabs are simulated as rigid diaphragms. Lead rubber bearing (LRB) and High damping rubber bearing (HDRB) are used as isolation device. Change of structural behaviors and savings in construction costing are evaluated. The study shows that for low to medium rise buildings, isolators can reduce muscular amount of base shears, base moments and floor accelerations for building at soft to medium stiff soil. Allowable higher horizontal displacement induces structural flexibility. Though incorporating isolator increases the outlay, overall structural cost may be reduced. The application of base isolation system confirms a potential to be used as a viable solution in economic building design.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.32-39
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• 2013

All spacecraft components shall be checked for compatibility with vacuum using CVCM and TML in advance. CVCM and TML of the PZT-5 piezoelectric vibrator has to be less than 0.1% and 1.0% respectively. Also, it has less than $500ng/cm^2/hr$ of TQCM for vacuum bake-out test using high temperature and high vacuum. Thus, the piezoelectric vibrator may be employed in the vacuum environments. Finally, it can be confirmed that the characteristics change of the piezoelectric vibrator is less than 1% under vacuum environments. Also, the temperature dependency of the characteristics in the PZT-5 piezoelectric vibrator with the lateral mode was investigated in the range of $-100^{\circ}C$ to $90^{\circ}C$ using the thermal vacuum chamber to utilize the vibrator to the aerospace industries. As the results, at room temperature, the resonant and anti-resonant frequencies had the minimum value, whereas, the dielectric constant increased linearly from about 2500 to 7500 in the given temperature range. The mechanical loss decreased linearly from 0.08 to 0.03.

• Restorative Dentistry and Endodontics
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• v.24 no.2
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• pp.356-363
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• 1999

The purpose of this study was to compare the apical sealing effect of Microseal obturation technique with lateral condensation technique in 26 recently extracted single rooted teeth. The root canals were instrumented using step-back technique and obturated with laterally condensed gutta-percha or Microseal. Teeth were suspended in methylene blue dye for 2 days and then longitudinary splited. The apical microleakage and the adaptability of gutta-percha to the root canal wall were examined under a stereomicroscope at ${\times}20$ magnification. The results were as follows: 1. The mean leakage was 1.38${\pm}$1.18 mm for laterally condensed gutta-percha group, and 0.71${\pm}$0.57 mm for Microseal gutta-percha group. But there was no statistical difference between two groups. 2. In Microseal gutta-percha group, they showed no gap between the master cone and Microseal gutta-percha, and showed homogeneous mass. 3. In contrast, laterally condensed gutta-percha group showed some gaps not only between gutta-percha cones, but also between gutta-percha cones and the canal walls, and the gaps were filled with some sealer. And also this group showed some amout of sealer on the root canal walls, Within the limits of the results of this experiment, Microseal gutta-percha obturation technique demonstrated relatively favorable apical sealing effect and shorter obturation time. Thus, it is thought that this obturation technique is a acceptable method for clinical use but further studies on this matter should be conducted.

• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.355-364
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• 2010

The purpose of this study was to investigate the kinematical analysis of T-stop motion by inline skate rolling speed. Six subjects were participated in the experiment(age: $35.0{\pm}3.3$ yrs, weight: $72.70{\pm}5.1\;kg$, height: $176.30{\pm}3.1\;cm$, career: $10.00{\pm}2.5$ yrs). The study method adopted 3-dimensional analysis and 2 cameras for filming to analyze the required displacement of center of mass, displacement of right and left hip joint, displacement of right and left knee joint, displacement of trunk tilt using by APAS. The results were as follows; In anterior-posterior displacement of COM, the faster rolling speed, the longer displacement at phase 2. In vertical displacement of COM, the faster rolling speed, the lower displacement. In medial-lateral displacement of COM, there was no significant on rolling speed. In angular displacement of right thigh segment, the faster rolling speed, the bigger displacement in X and Z axis. In angular displacement of left thigh segment, the faster rolling speed, the lower displacement in X axis. In angular displacement of right shank segment, the faster rolling speed, the bigger displacement in Z axis. In angular displacement of left shank segment, the faster rolling speed, the bigger displacement in X and Y axis. In angular displacement of trunk segment, the faster rolling speed, the bigger displacement in Z axis.

• Archives of Plastic Surgery
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• v.32 no.5
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• pp.573-581
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• 2005

Breast cancer is the second leading cause of death in woman. Unfortunately, the frequency of breast cancer and mastectomy are increasing in Korea. This paper introduces the breast reconstruction by use of pectoralis major muscle transfer with breast implant for small size defect after skin sparing mastectomy for more satisfaction. We reviewed 24 consecutive patients who underwent breast reconstruction by pectoralis major muscle transfer with implant and only breast implant in Dong-A University from April 2002 to March 2004. The patient's age ranged between 29 and 54 years with mean of 42.3 years. We used pectorals major muscle transfer with breast implant in 12 patients and breast implant alone in 12 patients as control. The follow-up period of patients ranged from 10 months to 3 years with mean of 18.5 months. The points of comparison with control group reconstructed by breast implant alone were doctor and patient satisfaction score, operation time, duration of admission, amount of drainage, complication and satisfaction according to mass location. In conclusion, there is no difference with control group in the point of operation time, mount of drainage, duration of admission. And there is higher level of doctor's and patient's satisfaction in group reconstructed by pectoralis major muscle transfer with breast implant than implant only group. Especially, pectoralis major muscle transfer with breast implant was especially necessary for the defect in upper lateral quadrant of the breast to get more satisfaction. The advantage of pectoralis major muscle transfer with breast implant is prevention of the protruding and palpability of implant and aesthetically satisfactory result by intraoperative modification of breast shape.

• Korean Journal of Head & Neck Oncology
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• v.13 no.1
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• pp.62-68
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• 1997

The papillary carcinoma is the most common malignant neoplasm of thyroid gland and the prognosis is better than anyother type of thyroid carcinoma. However, the thyroid is closed to the important organs such as esophagus, trachea and larynx, there are some possibilities to invade these organs. In case of advanced disease, not only surrounding structures but also mediastinum and cervical lymphatic chain can be involved or distant metastasis develops frequently. Therefore in these cases the prognosis is worse and the rate of inoperable case is more than those of non-metastatic group. Generally, the treatment modality for papillary thyroid carcinoma consists of surgery, postoperative thyroid hormone and radioiodine therapy. If the tumor invades surrounding structures, cervical lymph node or mediastinum, total thyroidectomy and wide excision of tumor invaded area including mediastinal dissection and neck dissection is necessary. Recently, the authors have experienced a case of locally invasive and recurred papillary thyroid carcinoma without treatment for 7 years. The patient was performed previously thyroid lobectomy and isthmusectomy 13 years ago. We had determinded surgical therapy for this patient and performed mass excision with overlying skin, completion total thyroidectomy, right type I modified radical neck dissection, left lateral neck dissection, thoracotomy with supramediastinal dissection, shaving of diffusely involved trachea and skin defect reconstruction with pectoralis major myocutaneous flap. After operation 2 cycles of radioiodine therapy were taken. Now the patient is following up at the outpatient base and no evidence of disease state for postoperative 16 months. So we report on this case with a brief review of literature.

• Hip & pelvis
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• v.30 no.4
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• pp.219-225
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• 2018

Purpose: Ischiofemoral impingement (IFI)-primarily diagnosed by magnetic resonance imaging (MRI)-is an easily overlooked disease due to its low incidence. The purpose of this study was to evaluate the usefulness of false profile view as a screening test for IFI. Materials and Methods: Fifty-eight patients diagnosed with IFI between June 2013 and July 2017 were enrolled in this retrospective study. A control group (n=58) with matching propensity scores (age, gender, and body mass index) were also included. Ischiofemoral space (IFS) was measured as the shortest distance between the lateral cortex of the ischium and the medial cortex of lesser trochanter in weight bearing hip anteroposterior (AP) view and false profile view. MRI was used to measure IFS and quadratus femoris space (QFS). The receiver operating characteristics (ROC), area under the ROC curve (AUC) and cutoff point of the IFS were measured by false profile images, and the correlation between the IFS and QFS was analyzed using the MRI scans. Results: In the false profile view and hip AP view, patients with IFI had significantly decreased IFS (P<0.01). In the false profile view, ROC AUC (0.967) was higher than in the hip AP view (0.841). Cutoff value for differential diagnosis of IFI in the false profile view was 10.3 mm (sensitivity, 88.2%; specificity, 88.4%). IFS correlated with IFS (r=0.744) QFS (0.740) in MRI and IFS (0.621) in hip AP view (P<0.01). Conclusion: IFS on false profile view can be used as a screening tool for potential IFI.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.3
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• pp.149-157
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• 2019

The purpose of this study is to investigate the effects of the significant duration of ground motions on responses of base-isolated nuclear power plants (NPPs). Two sets of ground motion records with short duration (SD) and long duration (LD) motions, scaled to match the target response spectrum, are used to perform time-history analyses. The reactor containment building in the Advanced Power Reactor 1400 (APR1400) NPP is numerically modeled using lumped-mass stick elements in SAP2000. Seismic responses of the base-isolated NPP are monitored in forms of lateral displacements, shear forces, floor response spectra of the containment building, and hysteretic energy of the lead rubber bearing (LRB). Fragility curves for different limit states, which are defined based on the shear deformation of the base isolator, are developed. The numerical results reveal that the average seismic responses of base-isolated NPP under SD and LD motion sets were shown to be mostly identical. For PGA larger than 0.4g, the mean deformation of LRB for LD motions was bigger than that for SD ones due to a higher hysteretic energy of LRB produced in LD shakings. Under LD motions, median parameters of fragility functions for three limit states were reduced by 12% to 15% compared to that due to SD motions. This clearly indicates that it is important to select ground motions with both SD and LD proportionally in the seismic evaluation of NPP structures.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.1
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• pp.63-70
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• 2023

Purpose : Excessive alcohol causes damage to skeletal muscles, leading to the development of a specific disease entity called alcoholic myopathy. Chronic inflammation is related as an underlying mechanism for the loss of muscle mass induced by alcohol. Pro-inflammatory cytokines such as TNF-α (tumor necrosis factor-α) and IL-6 (interleukin-6) play a role in this process. The acupuncture point Feng Shi (GB 31) is located on the midline of the lateral aspect of the thigh, above the transverse popliteal crease. This acupoint is used for the treatment of weakness, atrophy, numbness, and post-stroke symptoms of lower limbs. The purpose of this study was to investigate the effect of Feng Shi stimulation on muscle atrophy caused by chronic alcohol administration. Method : Young male Sprague-Dawley rats were randomly divided into three groups of eight each: Normal, Control, and GB31. The rats in the Control and GB31 groups were orally given 25 % ethanol (5 ㎖/kg, body weight) daily for 4 weeks. The Normal group was similarly administered saline. The acupressure at Feng Shi was treated to rats in the GB31 group. After 4 weeks, the body weight, muscle weight and cross-sectional area of gastrocnemius were assessed and the histological changes in gastrocnemius muscle fiber were observed by hematoxylin and eosin staining. Moreover, TNF-α and IL-6 expressions were immunohistochemistrically evaluated. Results : Acupressure stimulation at Feng Shi had a protective effect on the weight reduction of the gastrocnemius muscle caused by alcohol intake, and had an effect of suppressing anatomical change in muscle fiber and decreasing the average cross-sectional area. Also, the immunoreactivities of TNF-α and IL-6 in the GB31 group were decreased. Conclusion : These results suggest that acupressure at Feng Shi has protective effects on chronic alcohol-induced muscle atrophy by inhibiting pre-inflammatory proteins such as TNF-α and IL-6.