• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1031-1035
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• 2008

The importance of the more efficient cogeneration system is emphasized. Also the more clean energy is needed at recent energy system. The cogeneration system using Lean burn engine is more preferred to the system using Rich burn engine because of the electrical efficiency. Although the cogeneration system using Lean burn engine is economically preferred, because of the NOx emission level, the system using Rich burn engine with 3-way catalyst can only be used in Korea. The NOx regulation level is 50ppm at oxygen level 13%. The cogeneration hybrid system is consist of Lean burn gas engine, afterburner, boiler, economizer, DeNOx catalyst, combustion catalyst, absorption chiller, cooling tower and grid connection system. The system was accurately evaluated and the result is following ; 90% total efficiency, below 10ppm NOx, 50ppm CO, 25ppm UHC. The cogeneration hybrid system can meet the NOx level and exhaust gas regulation. It can achieve the clean combustion gas and efficient cogeneration system.

• Transactions on Electrical and Electronic Materials
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• v.5 no.4
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• pp.138-142
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• 2004

This paper presents the improved bum-in method for the reliability of SRAM in Multi Chip Package (MCP). Semiconductor reliability is commonly improved through the bum-in process. Reliability problem is more significant in MCP that includes over two chips in a package, because the failure of one chip (SRAM) has a large influence on the yield and quality of the other chips - Flash Memory, DRAM, etc. Therefore, the quality of SRAM must be guaranteed. To improve the quality of SRAM, we applied the improved wafer level bum-in process using multi cells selection method in addition to the previously used methods. That method is effective in detecting special failure. Finally, with the composition of some kind of methods, we could achieve the high quality of SRAM in Multi Chip Package.

• Archives of Plastic Surgery
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• v.32 no.5
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• pp.567-572
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• 2005

An electrical burn used to result in the damage of the skin and underlying deep soft tissue injury. Thus, in order to preserve devitalizing tissues and promote the structural survival free flaps with ample blood supply are frequently employed. However, early unpredictable vascular injury and progressive tissue necrosis may cause the free flaps full of hazards. We applied 50 free flaps upon 41 acute electrical burn cases between 1998 and 2004. Injured areas, timing of operation and causes of flap loss were studied. The victim's ages ranged from 13 to 60 years. (an average 37.8 years) Thirteen out of 50 free flaps were lost totally: three cases were due to arterial insufficiency and ten venous congestion. Total loss of flaps were observed in 5 of 12 cases in the postoperative 3 weeks, 6 of 20 cases between 3 and 6 weeks and 2 of 18 cases after 6 weeks. In three of 12 cases the free flap was lost partially in the postoperative 3 weeks, 4 of 20 cases between 3 and 6 weeks and 1 of 18 cases after 6 weeks. The result was statistically significant by a T-test (p<0.05). This study showed that timing of the operation is accountable for the loss of free flap. It is most important to conduct the free flap procedure on an electrical injury at the time when the recipient vessel is definitely discernible and intact so as to minimize the loss of flap and spare the structures.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.482-484
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• 2000

압전 세라믹은 공정 조건에 따라 압전 및 전기적 특성이 큰 영향을 받는다. 최적의 조건을 갖는 압전변압기를 제조하기 위해서는 이런 공정의 변수들의 변화를 관찰할 필요성이 있다. 본 논문에서는 이런 압전 특성을 관찰하고자, 하소의 온도를 $850^{\circ}C$에서 $900^{\circ}C$도까지 시간변화에 따라 phase 변화를 XRD로 관찰하고 burn out의 온도에 따른 기공변화 및 소결의 온도변화에 따른 임피던스 어낼라이저로 주파수 특성을 관찰하였다. 이렇게 조사해본 결과 하소를 $900^{\circ}C$에서 3시간 burn out을 $500^{\circ}C$에서 2시간, 소결을 $1250^{\circ}C$에서 2 시간 한 경우가 $Q_m>1000$, $k_p>0.40$ 값을 얻을 수 있었다.

• Archives of Reconstructive Microsurgery
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• v.10 no.1
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• pp.44-48
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• 2001

The pedicled fillet flap concept has been successfully applied in both the upper and lower extremities for the treatment of difficult wounds. However, in case of complete extremity amputation in eletrical burn patient, the transfer of pedicled flaps from the amputated part is not possible. In such instances, we have designed total arm musculocutaneous free-fillet flaps from the amputated limb to provide wound coverage, when replantation of the amputated part was contraindicated. now we present such a case. This technique allows immediate wound coverage without the morbidity of an additional donor site. The flap provides the ideal combination of large surface area, muscle bulk, and long vascular pedicle. It can be dissected rapidly to minimize ischemic time and could therefore be applicable to traumatic forequarter amputations.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.1005-1008
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• 1999

HMC has developed the lean burn system with alpha 4-valve into domestic market in the end of 1997. In a viewpoint of saving energy and prevention of global warming (CO2 reduction), the lean burn system has recently attracted a considerable attentions in gasoline engines. There has been, however, difficulty in extending LML(Lean Misfire Limit) enough to meet the emission regulations and satisfaction of driveability. In this paper some descriptions will be given upon the new technology of lean bum engine which will be installed in Accent, especially the improvement of the combustion, the development of engine management system such as intake system and wide range air fuel control strategy, and the result of vehicle test.

• Archives of Reconstructive Microsurgery
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• v.13 no.1
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• pp.14-23
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• 2004

Introduction: The hand and wrist are particularly susceptible to electrical burn. Skin defect with damage or exposure of underlying vital structure requires coverage by skin flap especially in case of the need for late reconstruction. We are reporting 4 cases of electrical burned hand treated by posterior tibial arterial free flap. The commonly used skin flaps such as scapular flap or groin flap are too bulky so that they are not satisfactory in function and cosmetic appearance. So we tried to cover them with a more thin skin flap. Materials and Method: From January 2002 to June 2003, four cases of hand and wrist electrical burn were covered using posterior tibial arterial free flap. All the cases were due to high voltage electrical burn. Age ranged from 31 years to 38 years old and all the cases were male patients. Recipient sites were 2 wrist, one thenar area and one knuckle of 2.3rd MP joint. Additional procedures were flexor tenolysis (simultaneous), FPL tenolysis and digital nerve graft (later) and extensor tendon reconstruction (later). Result: All the flap have survived totally without any complication including circulatory concern about the donar foot. Posterior tibail arterial free flap was so thin that debulking procedure was not required. Conclusion: For skin coverage of the hand & wrist region, posterior tibial arterial free flap have many advantages such as reliable anatomy, easy dissection and easy anastmosis with radial or ulnar artery and possibility of sensory flap. The most helpful advantage for hand coverage is its thinness. So we think this flap is one of the very useful armamentarium for reconstructive hand surgery.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.24-33
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• 1999

This paper investigate the effects of the variations of engine operation condition in the flame kernel formation and developmnet . A model for calculating the initial kernel development in spark ignition engines is formualted. It considered input of electrical energy, combustion energy release and heat transfer to the spark plyg, cylinder head, and unburned mixture. The model also takes into accounts strain rate of initial kernel and residual gas fraction. The breakdown process and the subsequent electrical power input initially control the kernel growth while intermediate growth is mainly dominated by diffusion or conduction. Then, the flame propagates by the chemical energy and turbulent flame expansion. Flame kernel development also influenced by engine operating conditions, for example, EGR rate, air-fuel ration and intake manifold pressure.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.340-344
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• 2008

The importance of the more efficient cogeneration system is emphasized. Also the more clean energy is needed at recent energy system. The cogeneration system using Lean burn engine is more preferred to the system using Rich burn engine because of the electrical efficiency. Although the cogeneration system using Lean burn engine is economically preferred, because of the NOx emission level, the system using Rich burn engine with 3-way catalyst can only be used in Korea. The NOx regulation level is 50ppm at oxygen level 13%. The cogeneration hybrid system using Lean burn engine is up to be optimized because of the large amount of the extra-fuel at the after-burner system. The after-burner system at different concept was applied. The reduction time for the activation temperature of the DeNOx catalyst was achieved by making a hole between the combustor and boiler. Because of the lowered fuel consumption, the lowered temperature level was optimized by blocking the hole of the boiler The optimized cogeneration hybrid system consumes $76Nm^3/h$ LNG to produce 150kW electricity compared to before optimization $103Nm^3/h$ LNG. The system was accurately evaluated and the result is following ; 90% total efficiency, below 10 ppm NOx, 50ppm CO, 25ppm HC. The cogeneration hybrid system can meet the current NOx level and exhaust gas regulation. It can achieve the clean combustion gas and efficient cogeneration system.

• Archives of Reconstructive Microsurgery
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• v.14 no.2
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• pp.144-151
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• 2005

Purpose: Disaster as traffic accident, industrial disaster, high voltage electrical bum and flame burn of extremity have a destructive effect because of the involvement of deep structure. Generally, such injury may result in decreased function or loss of limb. In this study the successful use of the combined scapular/parascapular flap as microsurgical transfer to cover extensive defect of electrical and flame bum is reported. Material and Method: Between January 2000 and June 2001, the combined scapular and parascapular flap was used for the coverage of soft tissue defect for 7 patients were admitted to our department with high voltage electrical bum and flame burn. The recipient site were the wrist joint in 2 cases, the forearm in 1 case, the ankle joint in 1 case, the foot dorsum in 1 case, the heel in 1 case. Result: Flap survival was complete in all patients. The result of flap coverage for these deep wound was successful. Conclusion: The advantages of scapular/parascapular combined flap were coverage of the large defect, easy shaping of the flap to fit the required three dimensional configuration around the joint, non hair bearing skin of uniform thickness, minimal donor site morbidity.