• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.659-666
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• 2010

Although the compression splice needs not be longer than the tension slice due to existence of end bearing, current design codes impose a longer compression lap splice than a tension lap splice in high strength concrete. Hence, new criteria for the compression lap splice including the effects of concrete strength need to be sought for economical design involving ultra-high strength concrete. An experimental study has been conducted with column specimens in concrete strength of 80 and 100 MPa. Test results show that the splice strength can be evaluated to be proportional to square root of compressive strength of concrete. Bar stress developed by end bearing is not affected by splice length and is expressed with a function of the square root of concrete strength. Mean value of stresses developed by end bearing is 16.5 square root of $f_{ck}$. The stresses developed by bond in compression splices are nearly identical to those in tension splices and, therefore, strength increment of compression splices is attributed to end bearing only. From regression analysis of 58 tests, a design equation is proposed for compression lap splice in 40 to 100 MPa of compressive strength of concrete. By the proposed equation, the anomaly of lap lengths in tension and compression is got rid of. In addition, the equation has a reliability equivalent to those of the specified strengths of materials.

• Journal of Dental Rehabilitation and Applied Science
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• v.40 no.1
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• pp.31-38
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• 2024

Dens in dente is a developmental anomaly resulting from infolding of the enamel organ into dental papilla prior to calcification of dental tissue. The pulpal tissue of the tooth can be vulnerable for bacterial invasion through direct exposure to the oral cavity or through defective enamel and dentin of the infolding part, thereby increasing the possibility of pulpal necrosis and subsequent apical periodontitis. Treatment planning of teeth with dens invaginatus may be difficult due to the complex root canal morphology. Therefore, thorough knowledge of anatomical variations of dens invaginatus is of great importance for proper treatment planning. The focus of this case report is on Oehler's type II and III dens invaginatus. The infolding of type III dens invaginatus extends beyond the crown and CEJ. Bacterial invasion through the infolding can easily cause inflammation of the pulpal and periradicular tissue. This case report presents endodontic treatment of type II and III dens invaginatus with the aid of CBCT.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.2
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• pp.174-179
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• 2014

Dens invaginatus is a developmental anomaly resulting from an infolding of the enamel organ into the dental papilla prior to calcification of the dental tissue. Clinical and radiographic presentation of dens invaginatus shows a lot of variation. The classification proposed by Oehlers(1957) is most commonly used among classifications of dens invaginatus. Several treatments have been suggested to treat Type III dens invaginatus where the pulp remains healthy but the invagination is associated with a periodontitis. The top priority objective is to preserve pulp as sound as possible. Thus, if there is no definite evidence of pulpal disease, the conservative access which treat invagination as distinct from the pulp is necessary. But, Endodontic treatment of Type III dens invaginatus has the particular problems associated with achieving adequate chemomechanical debridement of the root canal system and invagination, predictable length control and consistent filling. In this case report, the endodontic treatment limited within invagination was performed for treatment of Type III dens invaginatus, and filling with Mineral Trioxide Aggregate(MTA) resulted in good prognosis.

• Atmosphere
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• v.25 no.2
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• pp.271-281
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• 2015

The objectives of this study are to develop a hydrological drought outlook system using GloSea5 (Global Seasonal forecasting system 5) which has recently been used by KMA (Korea Meteorological Association) and to evaluate the forecasting capability. For drought analysis, the bilinear interpolation method was applied to spatially downscale the low-resolution outputs of GloSea5 and PR (Predicted Runoff) was produced for different lead times (i.e., 1-, 2-, 3-month) running LSM (Land Surface Model). The behavior of PR anomaly was similar to that of HR (Historical Runoff) and the estimated values were negative up to lead times of 1- and 2-month. For the evaluation of drought outlook, SRI (Standardized Runoff Index) was selected and PR_SRI estimated using PR. ROC score was 0.83, 0.71, 0.60 for 1-, 2- and 3-month lead times, respectively. It also showed the hit rate is high and false alarm rate is low as shorter lead time. The temporal Correlation Coefficient (CC) was 0.82, 0.60, 0.31 and Root Mean Square Error (RMSE) was 0.52, 0.86, 1.20 for 1-, 2-, 3-month lead time, respectively. The accuracy of PR_SRI was high up to 1- and 2-month lead time on local regions except the Gyeonggi and Gangwon province. It can be concluded that GloSea5 has high applicability for hydrological drought outlook.

• Clinical and Experimental Pediatrics
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• v.46 no.6
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• pp.597-601
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• 2003

Trisomy 9 mosaic syndrome is a rarely reported chromosomal abnormality with high incidence of intrauterine growth retardation and perinatal death. Even a baby lives, he has severe mental retardation and significant malformations. The incidence and severity of malformations and mental retardation correlate with the percentage of trisomic cells in the different tissues. The characteristic craniofacial abnormalitis are narrow bifrontal diameter, up-slanted and short palpebral fissures, a prominent nasal bridge with a short root, a prominent lip covering a receding lower lip, low-set, posteriorly rotated, and misshapen ears. Ventricular septal defect is a main cardiac abnormality. Bony hypoplasia and dislocated hips have been frequently reported. Central nervous system, hepatobiliary, gastrointestinal and genitourinary abnormalities also had been reported. The authors report a baby who had characteristic abnormalities of trisomy 9 mosaicism with narrow temples, up-slanted palpebral fissures, a bulbous nose, thin and protruding upper lip, low set and malformed ears, hyperextended wrist and overlapping fingers. Cytogenetic analysis performed to confirm the chromosomal abnormality revealed trisomy 9, low level mosaic type.

• Archives of Craniofacial Surgery
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• v.9 no.2
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• pp.85-89
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• 2008

Purpose: Unicoronal synostosis is the craniofacial anomaly caused by premature fusion of unilateral coronal suture. Ipsilateral flattening of the frontal and parietal bones, temporal retrusion with elevation and recession of the supraorbital rim are main clinical features. Compensatory contralateral frontal bossing and deviation of the nasal root and/or chin can also occur. There is a controversy about techniques for surgical correction, however, bilateral approach technique is more effective for correction of deformity. Methods: A 4-year-old patient with unicoronal synostosis had undergone unilateral suturectomy at 28-month-old but fronto-facial deformity had remained and aggravated as she grew older. She had both fronto-facial and endocranial asymmetry. We performed coronal cranial approach and fully exposed affected cranium including supraorbital rim. Anterior 2/3 calvarial reconstruction with bilateral frontal bone osteotomy and fronto-orbital bandeau advancement was performed. Results: Fronto-facial symmetry including fronto-orbital contour, nasal devation was improved. Endocranial twisting was also improved from $158^{\circ}$ to $162^{\circ}$ in CSO(crista gallisella turcica-opisthion) degree. There was no postoperative complications and no need for revision, and facial asymmetry improved at the period of 2 years of follow-up. Conclusion: Bilateral approach with fronto-orbital bandeau remodeling in surgery of unicoronal synostosis looked superior to unilateral approach in achieving better symmetry and preventing recurrence of asymmetry. Remodeling surgery should be tried in patients even at an older age to correct fronto-facial asymmetry.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.4 s.70
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• pp.347-360
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• 2005

The fuel rod instability can be occurred because of the axial and cross flow due to the flow anomaly and/or flow redistribution in the lower core plate region of the pressurized water reactor. The fuel rod vibration due to the hydraulic instability is one of the root causes of fuel failure. The verification on the fuel rod vibration and instability is needed for the new fuel assembly design to verify the fuel rod instability. In this study, the fuel rod vibration and stability analyses were performed to investigate the effect of the grid height, fuel rod support condition, and span adjustment on the fuel rod vibration characteristics for the advanced $16{\times}16$ fuel assembly design. Based on the analysis results, the grid height and grid axial elevation of the advanced $16{\times}16$ fuel assembly design were proposed.

• Atmosphere
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• v.26 no.1
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• pp.59-72
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• 2016

The comparison of prediction errors in geopotential height, temperature, and precipitation forecasts is made quantitatively to evaluate medium-range forecast skills between Global Seasonal Forecasting System version 5 (GloSea5) and Unified Model (UM) in operation by Korea Meteorological Administration during 2014. In addition, the performances in prediction of sea surface temperature anomaly in NINO3.4 region, Madden and Julian Oscillation (MJO) index, and tropical storms in western north Pacific are evaluated. The result of evaluations appears that the forecast skill of UM with lower values of root-mean square error is generally superior to GloSea5 during forecast periods (0 to 12 days). The forecast error tends to increase rapidly in GloSea5 during the first half of the forecast period, and then it shows down so that the skill difference between UM and GloSea5 becomes negligible as the forecast time increases. Precipitation forecast of GloSea5 is not as bad as expected and the skill is comparable to that of UM during 10-day forecasts. Especially, in predictions of sea surface temperature in NINO3.4 region, MJO index, and tropical storms in western Pacific, GloSea5 shows similar or better performance than UM. Throughout comparison of forecast skills for main meteorological elements and weather extremes during medium-range, the effects of initial and model errors in atmosphere-ocean coupled model are verified and it is suggested that GloSea5 is useful system for not only seasonal forecasts but also short- and medium-range forecasts.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.166-173
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• 2012

Dilaceration is a developmental disturbance in shape of teeth. It refers to an angulation, or a sharp bend or curve, in the root or crown of a formed tooth. Dilacerations are estimated to occur in 3% of all permanent dentitions. However, the etiology of dilaceration is not yet fully understood. Traumatic injury to the deciduous predecessors and ectopic development of the tooth germ are the two commonly cited causes of this anomaly. The involved tooth is usually the maxillary central incisor and it also shows high prevalence of impaction. At first, We tried to do surgical exposure with orthodontic traction but to no avail. After then surgical repositioning of the dilacerated tooth was performed. Finally, Satisfactory results were obtained at the end of treatment, with improvement in dental esthetics and functional aspects.

• Atmosphere
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• v.32 no.2
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• pp.149-162
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• 2022

This study investigated the prediction skill of the Asian dust seasonal forecasting model (GloSea5-ADAM) on the Asian dust and meteorological variables related to the dust generation for the period of 1991~2016. Additionally, we evaluated the prediction skill of those variables depending on the combination of the initial dates in the sub-seasonal scale for the dust source region affecting South Korea. The Asian dust and meteorological variables (10 m wind speed, 1.5 m relative humidity, and 1.5 m air temperature) from GloSea5-ADAM were compared to that from Synoptic observation and European Centre for medium range weather forecasts reanalysis v5, respectively, based on Mean Bias Error (MBE), Root Mean Square Error (RMSE), and Anomaly Correlation Coefficient (ACC) as evaluation criteria. In general, the Asian dust and meteorological variables in the source region showed high ACC in the prediction scale within one month. For all variables, the use of the initial dates closest to the prediction month led to the best performances based on MBE, RMSE, and ACC, and the performances could be improved by adjusting the number of ensembles considering the combination of the initial date. ACC was as high as 0.4 in Spring when using the closest two initial dates. In particular, the GloSea5-ADAM shows the best performance of Asian dust generation with an ACC of 0.60 in the occurrence frequency of Asian dust in March when using the closest initial dates for initial conditions.