• Journal of Korean Society for Atmospheric Environment
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• v.29 no.5
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• pp.625-633
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• 2013

This study attempted to find an alternative method for fine dust control in the pre-exiting facilities of metro-subway stations. A new double-layer design was proposed for the MVAC (mechanical ventilation and air control) system. Several filter lay-outs were combined a pre-filter with electret filter (EF), electret bundle filter (EBF), or electret pleated filter (EPF), and were then examined focusing on the collection efficiency of particulate matters and pressure drop across the filter layers. The experimental results from the lab and field tests showed the best collection efficiency with EPF, which achieved 85% for $PM_{10}$ and 55% for $PM_{2.5}$. It was also found from the long term field test that the new filter lay-out could provide quite consistent dust level particularly in underground platform regardless of external condition.

• Journal of Chest Surgery
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• v.16 no.3
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• pp.349-355
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• 1983

Twenty-seven patients with double-outlet right ventricle underwent complete intracardiac repair between 1978 and 1983, June, at Seoul National University Hospital . Although definite aorto-mitral discontinuity was discovered in 20 patients, both great arteries arose wholly or mostly from the right ventricle in all cases. There were 17 cases with subaortic VSD, 6 with subpulmonic, 2 with doubly-committed, and 2 with non-committed VSD. Pulmonary stenosis was present in 21 patients. Intraventricular baffle repair was applied in 23 patients. Three patients required extracardiac conduit to establish continuity between right ventricle and pulmonary artery, and modified Fontan operation was performed in one patient. Over-all mortality rate was 37.0%, but recently 4 of 15 died [26.7%]. One late death occurred from infective endocarditis. Incremental risk factors were small patient size, subpulmonic or non-committed VSD, presence of PS, coronary artery anomalies, associated valvular lesion and other complicated anomalies. However, great artery relationship, restrictive VSD and transannular patch were not risk factors. No instances of complete heart block occurred. Of the survivors, all showed complete or in complete right bundle branch block and in one patient intermittent ventricular tachycardia had developed. The important cause of death was low cardiac output syndrome.

• Journal of the Korean Arthroscopy Society
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• v.2 no.1
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• pp.1-3
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• 1998

The PCL reconstruction in chronic isolate PCL reconstruction was still controversy. 1) In isolate PCL deficient knee, functionally not so bad as like ACL deficient knee. 2) The result of the PCL reconstruction was not as good as ACL reconstruction. Therefore, isolate PCL injuries has been treated as nonoperatively. Hey Grovere, who was the first to attempt an intra-articular reconstruction of the PCL, utilized the semi-tendinous tendon other static procedures have been described in only a few cases with very limited follow-up. Dynamic procedures utilizing the medial head of the gastrocnemius has been reported by Hugston and Degenhardt, Kennedy and Grainger, and Insall and Hood. These procedures did not improve static stability. Dr Clancy, who was introduce the use of BPTB for the PCL reconstruction transtibial and femoral tunnel. From 1995, untill early 1990 PCL reconstruction was done as tend as placement of the isometric point. Physiometic placement of Anatomical placement of the femoral tunnel in PCL reconstruction were introduced in 1995. Tibial Inlay Technique was reported by Dr Berg in 1995. The main advantage of the tibial Inlay Technique was to avoid fraying of the graft at the posterior tibial tunnel orifice. In complete PCL ruptured and severely posterior unstable knee, dual femoral tunnel technique will be to get better result than one bundle technique. To achieve restoration of normal posterior laxity, it is critical to address the posterior as well as the posterolateral structures. Futher research is necessary to evaluate new surgical approches such as double-bundle reconstructions and tibial inlay techniques as well as improved techniques for capsular and collateral ligament injuries.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.266-271
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• 2009

The present study numerically investigated the effect of the geometry of the flattened tube on the thermal performance of a high temperature generator (HTG) of a double effect LiBr-water absorption system. The heat transfer tubes of the HTG were arranged behind a metal fiber burner. The heat transfer of the tubes of HTG were consisted with a set of circular and flattened tubes in series. FLUENT, as a commercial code, was applied for estimating the thermal performance of the HTG. Key parameters were the tube arrangement in the HTG. Temperature and velocity profiles in the HTG were calculated to estimate the thermal performance of the HTG. The heat transfer rate of a HTG tube was increased, and the gas temperature around the flattened tube was decreased as the pitch ratio was increased. The heat transfer rate for the circular tube bundle with the pitch ratio of 2.48 were larger by 10% respectively than that of 2.10 and the heat transfer rate for the flattened tube bundle with the pitch ratio of 1.88 were larger by 36% respectively than that of 1.63.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.7
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• pp.619-625
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• 2012

Since the fuel is always exposed to turbulent flow, the grid strap shows flow induced vibration characteristics that impact on the nuclear fuel soundness. The dynamic behavior of grids in nuclear fuels is quite complex, since two pairs of spring and dimple support are contacted with rods by friction in the limited space. This paper focuses on investigation of the grid strap(test fuel strap, TFS) vibration in one cell. TFS consists of a single spring and double dimples. To identify the grid strap vibration, modal analysis of the strap is performed using finite element method(FEM). Modal testing on a $5{\times}5$ grid structure without rods is performed. The modal testing results are compared to analytic results. In addition, random test considering rod effect is performed about a $5{\times}5$ grid with rods under real contact condition in the air. Finally, the strap vibration of a $5{\times}5$ fuel bundle in investigation of flow induced vibration(INFINIT) facility is measured in real fluid velocity condition without heating. It is shown that modal frequencies from the test are almost equal to those peak frequencies in the INFINIT test.

• Journal of Korean Orthopaedic Sports Medicine
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• v.12 no.1
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• pp.1-7
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• 2013

This article provides an overview of the current concepts regarding anterior cruciate ligament reconstruction, including anatomy, biomechanics, operative techniques and clinical results. Many techniques have been introduced for ACL reconstruction: single bundle reconstruction, remnant preserving augmentation, and double bundle reconstruction. Each technique has its strong and weak points, and it is not sure which technique is superior than others. It is considered to suggest that rather than to select the same method of surgery in all patients, select the method of reconstruction depending on the characteristics of the individual patient, the state of the residual ligaments and extent of the damage.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.4
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• pp.249-256
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• 2019

A full-scale test line was established to verify the electrical environmental interferences caused by the HVDC ±500 kV Double Bipole overhead transmission line with metallic return conductor, which is scheduled for construction in Korea and the fullscale test was conducted for one year. And through the human perception test of the DC electric-field under the HVDC Double Bipole line, the threshold value at which the human detects DC electric field was investigated to verify the validity of the design guide for the HVDC ±500 kV Double Bipole overhead transmission line. The polarity configuration of the HVDC ±500 kV Double Bipole test line was arranged diagonally with the same polarity in terms of the electrical environment disturbance and operation. The test line utilized the 6-bundle arrangement to prevent the corona discharge taking into account the domestic social acceptability. The test results show that the HVDC ±500 kV Double Bipole transmission line generated very little corona discharge from the conductors. Therefore, both DC electric field and ion current density met the domestic design guide for DC overhead transmission lines. Also, the human perception test of DC electric fields under the test line showed that 70% of participants did not recognize the DC electric field even when exposed to 23 kV/m.

• Journal of Biosystems Engineering
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• v.13 no.4
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• pp.9-19
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• 1988

The threshing of head-feed combine may be accomplished mainly by the action of impact between threshing teeth and rice. In this study, it was attempted to assess threshing performance characteristics of head-feed threshing teeth. And the characteristics of threshing teeth will be applied to the method which could analyze the time and order of impact between teeth and the rice, which was used as a basis for predicting the threshing performance and determining the optimum design parameters. The results of the study are summarized as follows: 1. About 50% of threshed material were threshed by the beginning 7 impacts on the rice bundle. Threshing torque decreased until 25 impacts and did not change thereafter. 2. There was significant difference in the threshability according to the shape of threshing teeth. The triangular-shaped tooth was the most efficient in threshability ratio and the semicircle-shaped tooth was the lowest. There was no significant difference in specific energy requirement for the varied teeth design. Torn-head ratio being generated by the semicircle-shaped and the triangular-shaped teeth in series was less than that by a single tooth with the triangular-shaped and the double setting of the triangular-shaped. Chaff generation ratio by the triangular-shaped and the semicircle-shaped teeth was less than the others tried. 3. The triangular-shaped teeth in series, which was newly designed for this study, showed an intermediate characteristics between the double setting of the triangular-shaped and the semicircle- shaped teeth. Threshability ratio of the triangular-shaped teeth in series was higher than that of the semicircle and lower than the double setting of the triangular-shaped tooth. Torn-head generation ratio for it was about same as that of the semicircle. Chaff being generated by the triangular-shaped teeth in series was about same as the double setting of the triangular-shaped teeth. 4. About 40% of threshed grains which passed through concave were concentrated under the threshing tooth and the rest of grains displayed a skew distribution toward the inlet of threshing chamber.

• Journal of the Korean Arthroscopy Society
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• v.16 no.1
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• pp.26-33
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• 2012

Purpose: The purpose of this study was to evaluate the clinical outcomes and stability of anatomical single bundle anterior cruciate ligament reconstruction (SBACLR) with quadriceps tendon comparable to double bundle anterior cruciate ligament reconstruction (DBACLR). Materials and Methods: We retrospectively reviewed 28 consecutive patients (16 male, 12 female) who underwent SBACLR using quadriceps tendon from March 2009 (Group 1) and compared its clinical results to whom DBACLR with semitendinosus tendon for 53 patients (51 male, 2 female) from August. 2006 (Group 2). Mean age were 34.9 (range, 16-52) in Group 1 and 21.6 (range, 17-55) in Group 2. Mean follow up periods were 13.9 months (range, 12-20) in Group 1 and 36.2 months (range, 20-52) in Group 2. Lysholm score, International Knee Documentation Committee (IKDC) evaluation form and Tegner score were performed for evaluating the clinical outcome. Lachman test, pivot shift test and KT-1000 arthrometer (MEDmetric Corp., San Diego, CA, USA) were performed for stability. Results: There was no statistical significant difference between the two groups in terms of Lysholm score (Group 1: $85.9{\pm}2.6$, Group 2: $90.9{\pm}1.0$, P=0.226), IKDC score (P=0.345) and Tegner score (Group 1: $6.9{\pm}1.4$, Group 2: $7.1{\pm}1.3$, P=0.523). Nor was there statistical significance between the two groups in terms of KT-1000 arthrometer (Group 1: $1.5{\pm}1.1\;mm$, Group 2: $1.5{\pm}1.6\;mm$, P=0.457), Lachman test (P=0.547) and pivot shift test (P=0.073). Conclusion: Anatomical SBACLR with quadriceps tendon shows similar clinical outcomes and stability comparable to anatomical DBACLR with hamstring tendon.

• 대한관절경학회:학술대회논문집
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• 2007.10a
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• pp.34-35
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• 2007