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Consideration on Usability of Modified Sulfur of Low-Slump Concrete (저슬럼프 콘크리트의 개질유황 사용성에 대한 검토)

  • Shin, Hyo-Chul;Kim, Gyu-Yong;Kim, Jung-Hyun;Kim, Jin-Man
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.11a
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    • pp.109-110
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    • 2015
  • In this study, fresh state properties and mechanical properties of low slump concrete which is applied to road pavement have been evaluated by mixing modified sulfur. As results, influence of mixing modified sulfur on the workability was low. Also, compressive strength, and flexural strength tend to decrese with increasing addition rate of modified sulfur. However compressive strength, and flexural strength of modified sulfur concrete were equivalent with that of plain concrete.

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Delayed Posttraumatic Spinal Epidural Hematoma: Importance of Early Surgical Treatment for Neurologic Deficits

  • Lee, Deok Heon;Oh, Tak-Hyuk;Lee, Jong-Chul;Lim, Kyoung Hoon
    • Journal of Trauma and Injury
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    • v.29 no.4
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    • pp.176-179
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    • 2016
  • Delayed posttraumatic spinal epidural hematoma is an extremely rare disease, and it remains a challenge for surgical teams of trauma centers. Magnetic resonance imaging is an essential tool for early diagnosis, and emergent evacuation of the hematoma is the best choice of treatment. We report the case of a 33-year old man with posttraumatic epidural hematoma in the thoracic spine (T10 and T11 levels), who developed an abrupt-onset paraplegia 5 days after the trauma.

Thermal Fatigue Reliability of Solder Joints in a Thin Film Optical Filter Device (박막 광학 필터 디바이스의 패키징시 솔더 조인트의 피로 신뢰성 해석)

  • Lee, Sung-Chul;Hyun, Chung-Min;Lee, Hyung-Man;Kim, Myoung-Jin;Kim, Hwe-Kyung;Kim, Ki-Tae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.6
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    • pp.677-684
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    • 2004
  • Plastic and creep deformations of solder joints during thermal cycling are the main factors of misalignments and power losses in optical telecommunication components. Furthermore, the increased mismatch between solder Joint-bonded areas may cause severe failure in the components. Darveaux's creep model was implemented into a finite element program (ABAQUS) to simulate creep response of solder. Based on the finite element results, thermal fatigue reliability was predicted by using various fatigue life prediction models. Also, the effects of ramp conditions, dwelling time, and solder joint-embedding materials on the reliability were investigated under the thermal cycling conditions of the Telcordia schedule (-40∼75$^{\circ}C$).

Harmonic Reduction of Three Phase Multi-Pulse Converter Circuit without Input Transformer (입력 변압기 없는 3상 멀티-펄스 콘버터의 고조파 저감)

  • Park, Hyun-Chul;Kim, Yeong-Min;Hwang, Jong-Sun;Kim, Jong-Man
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.05b
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    • pp.128-131
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    • 2002
  • In this paper, a new method for reducing harmonic in input AC line currents of converter presents, which is the multi-pulse converter circuit without the input transformer. This system can reduce the harmonic like conventional 12-pulse converter. Both the bridge circuits are controlled with the shifted firing angle and connected 2 tap inter-phase reactor. Using 2 tap changing on inter-phase reactor, the input current is controlled with the different two values in order to make the input current waveform 12 pulses.

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Design of the CMOS Low-Voltage Regulation Circuit (CMOS 소자를 이용한 저전압 안정화 회로 설계)

  • Kim, Yeong-Min;Lee, Keun-Ho;Hwang, Jong-Sun;Kim, Jong-Man;Park, Hyun-Chul
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.05b
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    • pp.124-127
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    • 2002
  • A CMOS voltage regulation circuit for use at low-voltage is proposed. Circuits for a positive and for a negative current regulation are presented and are designed with commercial CMOS technology. The voltage regulation that is stable over ambient temperature variations is an important component of most data acquisition systems. These results are verified by the H-SPICE simulation $0.8{\mu}m$ parameter. As the result, the temperature dependency of output voltage is $0.57mV/^{\circ}C$ and the power dissipation is 1.8 mV on 5V supply voltage.

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A Modular System of the Propagation Neural Networks For Reconstruction of Lost Information (소실 정보의 복원을 위한 전송신경망 모듈라 시스템)

  • Kim, Jong-Man;Kim, Yeong-Min;Hwang, Jong-Sun;Kim, Hyun-Chul
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.05b
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    • pp.119-123
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    • 2002
  • A new modular Lateral Information Propagation Networks(LIPN) has been designed. The LIPN has shown to be useful for reconstruction of information[3]. The problem is the fact that only the small number of nodes can be implemented in a IC chip with the circuit VLSI technology. The proposed modular architecture is propagated the neural network through inter module connections. For such inter module connections, the host (computer or logic) mediates the exchange of information among modules. Also border nodes in each module have capacitors for temporarily retaining the information from outer modules. The LIPN with $4{\times}4$ modules has been designed and simulation of interpolation with the designed LIPN has been done.

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Knowledge-based System for Power Generator Annual Maintenance Scheduling (발전기 연간 정기보수계획을 위한 지식 베이스 시스템)

  • Ahn, Byong-Hun;Kim, Chul;Shin, Jae-Yeong;Lee, Kyung-Jae;Kwon, Tae-Won;Lee, Byung-Ha;Ham, Wan-Kyun
    • Proceedings of the KIEE Conference
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    • 1991.11a
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    • pp.47-50
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    • 1991
  • This paper discusses a knowledge-based system being developed by KAIST and KEPCO to assist planning the annual maintenance schedule of power units. To meet users' requirements, we have designed the system with several features: man-machine interaction, catalog system, user-friendliness, the hybrid-system of math-model and knowledge-base. In this paper, we introduce the outline of our system.

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Prediction of Propulsive Performance of VLCC at Heeled and Trimmed Conditions (대형유조선의 경사상태011서의 저항추진 성능추정)

  • Yang, Ji-Man;Kim, Hyo-Chul
    • Journal of the Society of Naval Architects of Korea
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    • v.42 no.4 s.142
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    • pp.307-314
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    • 2005
  • In recent years, many environmentally disastrous oil spill accidents from damaged vessels become worse especially when the early treatment is not prompt enough. To properly handle this type of accidents and prevent further disasters, international organizations establish and impose various rules and regulations. In assessing the damages and providing salvage operations, the propulsive performance of damaged vessels is of great importance, as well as for containing oil spill while the vessels are being towed or self-propelled. Until now, many naval hydrodynamics researches have focused on the propulsive performance in normal operating conditions and only a few studies for damaged vessels are found in literature. In this paper experimental method is used to study the Propulsive performance of a very large crude-oil carrier (VLCC) in .heeled and/or trimmed conditions.

Intrathoracic Lesion Showing Multiple Cysts and Pneumothorax (다발성 낭종과 기흉을 보이는 흉곽내 병변)

  • Song, Hyun-Mo;Lee, Heung-Bum;Lee, Yong-Chul;Rhee, Yang-Keun;Han, Young-Min
    • Tuberculosis and Respiratory Diseases
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    • v.42 no.3
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    • pp.419-423
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    • 1995
  • Pulmonary histiocytosis X is an idiopathic benign disease characterized by proliferation and infiltration of lung tissue by characteristic Langerhans cells and eosinophils. Pulmonary histiocytosis X is common in young male adults, and shows variable clinical characteristics. We experienced a case of pathologically proven pulmonary histiocytosis X in a 30-year-old man who visit to our hospital due to chest discomfort and cough. The chest radiograph of our patient shows right pneumothorax and characteristic multiple thin-walled cysts on the both upper lung fields. The HRCT shows multiple thin-walled cysts, a few scattered nodules in both upper and right middle lung, and right pneumothorax.

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