• 한국자동차공학회논문집
• /
• 제20권3호
• /
• pp.20-25
• /
• 2012

As a kind of distributed energy system, the co-generation system based Diesel engine using after-treatment device was devised for its environmental friendly and economic qualities. It is utilized in that the electric power is produced by the generator connected to the Diesel engine, and waste heat is recovered from both the exhaust gases and the engine itself by the finned tube and shell & tube heat exchangers. An after-treatment device composed ceramic heater and DOC(Diesel Oxidation Catalyst) is installed at the engine outlet in order to completely reignite the unburned fuel from the Diesel engine. In this study, mutual relation of each experimental condition was derived through minimum number of experiment using Taguchi Design and ANOVA recently used in the various fields. It is found that the total efficiency (thermal efficiency plus electric power generation efficiency) of this system reaches maximum 94.4% which is approximately higher than that of the typical diesel engine exhaust heat recovery system.

• 감성과학
• /
• 제7권2호
• /
• pp.179-186
• /
• 2004

중추신경계는 일단 손상이 되면 손상된 세포의 재생, 손상된 수초의 회복, 신경계의 정상적인 연결 등의 제한성 때문에 그 회복이 매우 힘들다. 이러한 중추신경계의 중요한 손상으로는 다발성 경화증, 뇌졸중, 척수손상, 외상, 축삭의 탈수초화 등이 있다. 이전 연구들은 많은 발생빈도를 보이고 있는 척수손상에서 실질적인 척수의 기능적인 회복을 위해 손상된 척수신경의 재생과 축삭의 재수초화가 중요한 요인이라고 전하고 있다. 최근에는 이러한 척수손상에 대한 치료적 접근으로서 세포이식 기술이 하나의 해결책을 열어주고 있다. 따라서 본 논문에서는 척수손상의 특성을 살펴보고, 척수손상에 의한 기능장애에 대해 세포이식이 기능의 회복을 증진시킬 수 있다는 증거를 논의하고자 한다.

• Journal of Acupuncture Research
• /
• 제24권6호
• /
• pp.137-148
• /
• 2007

Objectives : Following central nervous system (CNS) injury, inhibitory influences at the site of axonal damage occur. Glial cells become reactive and form a glial scar, know as gliosis. As well,myelin debris such as MAG inhibits axonal regeneration. Astrocyte-rich gliosis relates to up-regulation of GFAP and CD81, and eventually becomes a physical and mechanical barrier to axonal regeneration. It is postulated that when the astrocytic reaction is absent, regeneration of axons can occur. It was reported that treatment with anti CD81 antibodies enhanced functional recovery in rats with spinal cord injury. Methods : MAG is one of several endogenous axon regeneration inhibitors that limit recovery from central nervous system injury and disease. It was reported that molecules which block such inhibitors enhanced axon regeneration and functional recovery. Results : In this current study, the author investigated the effect of the water extract of Ginseng Radix on the regulation of CD81, GFAP and MAG which increases when gliosis occurs. MTT analysis was performed to examine cell viability, and cell based ELISA, Western Blot and PCR were used to detect the expression of CD81, GFAP and MAG. Immunohistochemistry was also performed to confirm in vivo. Conclusions : We observed that Ginseng Radix significantly down-regulates the expression of CD81, GFAP and MAG by means of cell based ELISA, Western Blot and PCR. In immunohistochemistry, expression of CD81, GFAP and MAG also decreased. Taken together, these results suggest that Ginseng Radix can be a candidate for regenerating CNS injury.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집D
• /
• pp.732-737
• /
• 2001

The mathematical method was developed and numerical analyses were carried out with various parameters to provide substantial data for optimal design and operation of urban utility systems. The composition of systems and their specifications, such as co-generation system, heat pump system, incineration system and other heating and cooling system could be obtained through these analyses for various resource and energy requirements in urban area. As results the system constituents and operating characteristics, and their economic performances such as the value of objective function, initial and an operating costs were discussed for various load patterns. The effective system design method and the excepted effects of the several unused energy recovery systems were also briefly discussed with the variation of the buildings and facilities species and their capacities.

• 대한기계학회논문집A
• /
• 제25권4호
• /
• pp.685-694
• /
• 2001

In this study, a transfemoral prosthesis system of which both stance phase and swing phase are controllable has been developed for the recovery of the biomechanical function of the amputated leg. It consists of a 5 bar link mechanism, a hydraulic-rubber knee damper for stance phase control and a pneumatic cylinder controlled via a microprocessor for stance phase control. The mechanical characteristics of the knee damper which absorbs the impact energy generated at the heel contact were investigated. The characteristics of the pneumatic cylinder essential for the speed adaptation of the prosthesis during swing phase were also studied for its mechanical characteristics. The prosthesis was subject to the clinical tests, and the gait characteristics obtained were very close to those of normal subjects. The stance and swing controlled prosthesis that were developed in this study showed good stability during the stance phase and showed good controllability during the swing phase.

• 설비공학논문집
• /
• 제20권5호
• /
• pp.314-320
• /
• 2008

The cooling load in winter is significant in buildings and hotels because of the usage of office equipments and the improved wall insulation. Hence, a multi~heat pump is required to cover heating and cooling simultaneously for each indoor unit. In this study, the operating characteristics and performance of a simultaneous heating and cooling heat pump in the cooling-main operating mode were investigated experimentally. The system adopted a variable speed compressor using R410A with four indoor units and one outdoor unit. In the cooling-main mode, the heating capacity decreased due to reduction of flow rate to the indoor unit under heating mode operation. The EEV opening was adjusted to increase flow rate to the indoor unit under heating mode operation. The total capacity and COP in the cooling-main mode increased by 20.5% and 29.2%, respectively, compared with those in the cooling-only mode.

• 한국정보처리학회논문지
• /
• 제6권1호
• /
• pp.216-224
• /
• 1999

날로 더욱 복잡해지는 제어 컴퓨터의 고 신뢰성 확보를 위해 시간여분(time redundancy)의 일종인 rollback과 roll-forward 기법 등을 TMR 구종에 적절하게 혼용하는 두 가지 방법을 제안한다. Rollback과 roll-forward 기법은 약간의 추가시간만을 사용하여 재구성(reconfiguration) 없이도 일시적인 결함(fault)에 의해 발생한 TMR 고장(failure)의 회복을 위해 상호보완적으로 사용될 수 있다. 본 논문은 시스템의 고장상태확률의 유도를 통해 전체 작업의 평균실행시간이 최소가 되는 최적의 checkpoint 간격벡터를 유도한다. 수치예제를 통해 제안된 방법들이 다른 고장회복 기법을 적용했을 때와 비교하여 매우 효과적임을 보이고, 다양한 환경 하에서 여러 가지 최적의 checkpoint 간격벡터를 유도하였으며, 시뮬레이션을 통한 정량적 결과로써 그 우수성을 비교하고 검증하였다

• 대한기계학회논문집B
• /
• 제27권10호
• /
• pp.1361-1369
• /
• 2003

Design performance of hybrid power generation systems, comprised of a gas turbine and an atmospheric pressure molten carbonate fuel cell, has been analyzed. Two different configurations were analyzed and performances were compared. A reference calculation was performed for the design condition of a system under development and simulated results agreed well with the published data. Performances were analyzed in terms of main design parameters including turbine inlet temperature, operating temperature of the fuel cell and pressure ratio. Also examined were the effects of fuel utilization factor and heat exchanger effectiveness. It was found that the relationship between the turbine inlet temperature and the fuel cell temperature should be critically examined to evaluate achievable design performance. Considering current state of the art technologies, a system with the combustor located before the turbine could achieve higher efficiency and specific power than the other system with the combustor located after the turbine.

• 대한기계학회논문집B
• /
• 제33권12호
• /
• pp.968-976
• /
• 2009

As the global warming becomes a serious environmental problem, studies of reducing $CO_2$ emission in power generation area are in progress all over the world. One of the carbon capture and storage(CCS) technologies is known as oxy-fuel combustion power generation system. In the oxy-fuel combustion system, the exhaust gas is mainly composed of $CO_2$ and $H_2O$. Thus, high-purity $CO_2$ can be obtained after a proper $H_2O$ removal process. In this paper, an oxy-fuel combustion cycle that recovers the waste heat of a high-temperature fuel cell is analyzed thermodynamically. Variations of characteristics of $CO_2$ and $H_2O$ mixture which is extracted from the condenser and power consumption required to obtain highly-pure $CO_2$ gas were examined according to the variation of the condensing pressure. The influence of the number of compression stages on the power consumption of the $CO_2$ capture process was analyzed, and the overall system performance was also investigated.

• 한국기계기술학회지
• /
• 제20권6호
• /
• pp.739-744
• /
• 2018

In this study, effects of reducing white smoke at a heat exchange system for white smoke reduction were studied in the winter season. For this purpose, the heat transfer processes on the exhaust air were investigated by Solidworks. Five wave heat exchangers of air-to-air and air-to-water type were applied for the exhaust air heat recovery. The analytical condition of the exhaust air was fixed and the computational analysis was performed according to the change of SA(supply air) inlet velocities. In order to evaluate the performance of the heat exchange system for white smoke reduction, W(water)/SA recovered capacities and the temperature/absolute humidity reduction rate were calculated. As SA inlet velocity increased, the exit temperature and absolute humidity of the mixing zone were reduced by up to about $40^{\circ}C$ and 0.12kg/kg respectively. Also, W/SA recovered capacities increased linearly up to about 35%.