• Journal of Korean Society of Steel Construction
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• 제16권5호통권72호
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• pp.565-574
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• 2004

The purpose of this paper was to investigate the block shear and the fracture in the net section, according to AISC Specifications, by analysing the shear lag effect in the block shear rupture of the single angle with three or four bolt connection. Specimen with three or four bolt connections showed that failure generally went from block shear with some net section failures to classic net section failures. From the test results, showed that the connection length, the thickness of angle, and reduction factor, which affect the block shear rupture, were investigated. According to the test results, it is suggested that the calculation of the net section rupture capacity by using the reduction factor of U, that was suggested by Kulak, is needed.

• Proceedings of the KIEE Conference
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1292-1294
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• 2002

In this study, the block section length of the given area has been analyzed to improve the headway which caused by the mixed operation of high speed trains and normal trains on the electrified railway of Dongdaegu to Busan. After establishing the average length of block section and the adjustable average length of block section of Dongdaegu to Busan, it is possible to perform the headway simulation regarding the signal system based on the established length. Although high speed trains as well as low speed trains including freight trains operate together, the experimental results indicate that the modification of the block section length shows the possibility of the improvement of headway.

• Proceedings of the KIEE Conference
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.451-454
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• 1995

Increasing the transfortation efficiency is very important issue in railway system. Speed-up of train and shortage of headway can be its solution. Headway can vary with blocksection length, characteristics of the railway and signalling systems. Safety braking distance needed for passenger's safety is very important factor in block section division method. In this study, basic block section division program was developed with the differential ratio of braking distance resulted by grade value of the track. More complete block section division program is going to be developed by the help of experienced experts.

• Transactions on Electrical and Electronic Materials
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• 제18권2호
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• pp.62-65
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• 2017

In this paper, three DC Block designs are presented which efficiently meet the need of modern-day compactsize wireless communication systems. As one of the important parts of a complete system design, the proposed microstrip-based DC block with coupled transmission lines efficiently attenuates unwanted frequencies that cause damage to the system. The compact-sized DC block structures are created by incorporating an extended coupled-line section with a radial stub, an enveloped coupled-line section, and using alternate up-down meandering techniques. The structures are analyzed for the L-Band using a high-resistive silicon substrate. At a resonating frequency of 1.575 GHz, the designed DC Block structures have a return loss better than -10 dB, an insertion loss of around -1 dB, and also possess wide pass-band characteristics.

• The Korean Journal of Pain
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• 제32권4호
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• pp.286-291
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• 2019

Background: Breast cancer is complicated by a high incidence of chronic postoperative pain (25%-60%). Regional anesthesia might play an important role in lowering the incidence of chronic pain; however it is not known if the pectoral nerve block (PECS block), which is commonly used for breast surgery, is able to prevent this complication. Our main objective was therefore to detect any association between the PECS block and chronic pain at 3, 6, 9, and 12 months in patients undergoing breast surgery. Methods: We conducted a prospective, monocentric, observational study. We enrolled 140 consecutive patients undergoing breast surgery and divided them in patients receiving a PECS block and general anesthesia (PECS group) and patients receiving only general anesthesia (GA group). Then we considered both intraoperative variables (intravenous opioids administration), postoperative data (pain suffered by the patients during the first 24 postoperative hours and the need for additional analgesic administration) and development and persistence of chronic pain (at 3, 6, 9, and 12 mo). Results: The PECS group had a lower incidence of chronic pain at 3 months (14.9% vs. 31.8%, P = 0.039), needed less intraoperative opioids (fentanyl $1.61{\mu}g/kg/hr$ vs. $3.3{\mu}g/kg/hr$, P < 0.001) and had less postoperative pain (3 vs. 4, P = 0.017). Conclusions: The PECS block might play an important role in lowering incidence of chronic pain, but further studies are needed.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.75-78
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• 2008

Limit states of a tension member are the yielding of gross section, fracture of net section, and block shear failure. Block shear failure is very complicated than other limit state because of interaction of tension and shear failure. Block shear failure is studied continuously since the 1970s. However, failure model to estimate the strength of block shear failure provided in current design specifications is not reflective of the failure mode observed in the various experimental studies. Comparisons between the experimental results and design rules in various specifications about the block shear failure were conducted in this study. Also, the need for further studies of block shear failure were proposed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• 제46권1호
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• pp.60-63
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• 2009

In this paper, Designed and implemented about module that generate division signal for uplink section and downlink section for controlling Tx/Rx antenna of 2.3-2.7GHz WiMAX TDD repeater. It is consisted of RF block and Baseband block, and because function of this module is that synchronize with WiMAX signal and create division signal for uplink section and downlink section, this module was designed only received path. And because of manufacturing of most RF block by one chip, this module could minimize area. And in baseband block, used the WiMAX Modem to detect Preamble and DL-MAP information of WiMAX signal. This design can process about 2.3-2.7GHz WiMAX.

• Journal of the Korean Geosynthetics Society
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• 제18권2호
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• pp.23-36
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• 2019

In this paper, field measurement of the Block Type Mechanically Stabilized Earth (MSE) wall curved section was performed, and the reinforced area of the curved part is studied through the result. MSE method has been applied to various fields because of easy construction and excellent economic efficiency, so that it can be easily access in our life. However due to lack of compaction and stress concentration phenomenon, cracks and collapse occur in the curve of MSE wall, which is important for safety. The cause of collapse is lack of research on curved section, lack of design criteria, lack of construction due to economical efficiency and shortening of construction period, insufficient compaction space. In this study, therefore, it was examined the existing design and construction standards, analyzed the cause through accident examples of the curved section of the Block Type MSE wall. As a result, the horizontal displacement of the curved section was 90% higher than that of the straight section and 60% higher than that of the concave section. In the case of the convex section in the curved section reinforcement region, the maximum displacement is shown in the H/2 section in the horizontal direction from the center of the MSE wall, and the range of influence from H is shown. In the case of the concave section, the maximum displacement is shown in the center, The minimum displacement was confirmed in H/4 section in the horizontal direction from the center of the MSE wall. As a basic study on the reinforcement area rehabilitation through the actual construction of block type MSE wall, the behaviors of the straight part and the curved part were compared and analyzed. And analyzed the reinforced area in order to reduce the damage of the stress concentration phenomenon and secure the safety.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.137-139
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• 2003

As a part of numerical and experimental research works for the prediction and improvement of ship's maneuvering performance, a study on the performance analysis of two different rudders has been carried out. While the planform shape and the aspect ratio of the rudders have been fixed, section shape has been changed. Conventional type of HMRI NP section and special type of dolphin-tail section have been employed. Performances of the rudders have been investigated by using CFD and compared with experimental data obtained in a wind tunnel. A commercial CFD program has been used to solve the RANS equations. Two-equation k-ro model has been applied to close the governing equations. Block-structured grids are used in the numerical calculation. Based upon the calculation results, the rudder with dolphin-tail section has shown a possibility of significantly improving rudder performance if utilized as the section of ship rudders.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제64권10호
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• pp.1523-1527
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• 2015

Traction power is supplied by three-phase alternating current of 154 kV power grid and electric trains are operated on single phase feeding system. It becomes important to use all the three phases equally and convert them into two-phase electric power (90 degree phase rotation) for traction supply. This is achieved by special transformer from the adjacent traction substation which is separated by a neutral section. Neutral section locations are in front of the substation and between the two substations. The first stage of the Seoul-Busan high-speed railway, design curve radius is larger than 7,000 m and the greatest slope is 25‰. The railway track conditions are evaluated as good enough to install a neutral section at the first stage, but a few factors of coasting operation of the train should be considered at the second stage of Seoul-Busan high-speed railway. The neutral section was located at Kim-cheon substation, which made some neutral section problems produced by the operating train, and the neutral section was moved about 1.5 km to the south toward Dong Dae-gu station due to the track operation condition. Some of the trains which stopped at the existing Kim-cheon Gu-mi station produced another motor block failure after moving the neutral section. In this paper, power quality, system performance and track condition, etc. are suggested to solve the problems.