• KSBB Journal
• /
• v.23 no.5
• /
• pp.449-451
• /
• 2008

Ceramide has become a widely used ingredient in cosmetic and pharmaceutical industries, however, only a few yeast strains were investigated for the synthesis of ceramide and the concentration was very low. Ceramide is not only a core intermediate of sphingolipids but also an important modulator of many cellular events including apoptosis, cell cycle arrest, senescence, differentiation, and stress responses. In this study S.cerevisiae was grown in a batch culture and the cellular content of ceramide was measured at different growth phases. The ceramide content was highest at stationary phase and 2.01 mg ceramide/g cell was obtained.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.5
• /
• pp.596-603
• /
• 2013

The increase of distributed power generation is closely related to interest in microgird including renuable energy sources such as photovoltaic (PV) systems and fuel cell. By the growing interest of microgrid all over the world, many studies on microgrid operation are being carried out. Especially operation technique which is core technology of microgrid is to supply heat and electricity energy simultaneously. Optimal microgrid scheduling can be established by considering CHP (Combined Heat and Power) generation because it produce both heat and electricity energy and its total efficiency is high. For this reason, CHP generation in microgrid is being spotlighted. In the near future, wide application of microgrid is also anticipated. This paper proposes a mathematical model for optimal operation of microgrid considering both heat and power. To validate the proposed model, the case study is performed and its results are analyzed.

• Journal of the Korean Electrochemical Society
• /
• v.12 no.3
• /
• pp.219-233
• /
• 2009

Mobile devices in the next generation such as camera, cell phone, network, Note PC, etc. require higher power and energy sources due to convergences of various functions. Direct methanol fuel cell (DMFC) has been focused as an attractive power source, but there are critical issues involved in its commercialization with regard to the core technologies of materials, components, and system. The requirements of key technologies are differentiated from applications and fuel supply methods. Here, the roles of the proton-conducting membrane are discussed and the current status of DMFC systems is discussed in terms of proton conductivity, methanol permeability, and water management. Materials such as perfluorinated and partially fluorinated membranes, hydrocarbon membranes, composite membranes, and other modified ionomers have been studied. These would explain the critical issues of DMFC and the role of membranes for commercialization.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.2 no.3
• /
• pp.197-204
• /
• 2002

DRAM, SRAM, and FLASH memory are three major memory devices currently used in most electronic applications. But, they have very distinct attributes, therefore, each memory could be used only for limited applications. MRAM (Magneto-resistive Random Access Memory) is a promising candidate for a universal memory that meets all application needs with non-volatile, fast operational speed, and low power consumption. The simplest architecture of MRAM cell is a series of MTJ (Magnetic Tunnel Junction) as a data storage part and MOS transistor as a data selection part. To be a commercially competitive memory device, scalability is an important factor as well. This paper is testing the actual electrical parameters and the scaling factors to limit MRAM technology in the semiconductor based memory device by an actual integration of MRAM core cell. Electrical tuning of MOS/MTJ, and control of resistance are important factors for data sensing, and control of magnetic switching for data writing.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2003.10a
• /
• pp.14-18
• /
• 2003

Feul-cell system consists of fuel reformer, stack and energy translator. Among these parts, slack is a core part which produces electricity directly. In order to set a stack module, fabrication of appropriate stack, design of water flow path in stack, and control of coolant are needed. Especially, water or air is used as a coolant to dissipate heat. The different temperature of each electric cells after cooling and the high temperature of the stack affect the performance of the stack, Therefore, it is necessary that the relationship between coolant, healing rate, width of slack, properties of stack, and the shape of water flow path must be understood. For the optimal design, the computational simulation by CFD-ACE has been conducted and the resulting database has been constructed.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2003.11a
• /
• pp.91-95
• /
• 2003

In this work, we have designed Gilbert cell downconversion mixer using 0.25um Anam CMOS process, we also have analyzed Conversion gain and IIP3 using Taylor series in our own unique way. Especially, bulk terminal is used as LO( Local Oscillator) input for reduction of power consumption and supply voltage. Supply voltage used in this design is lower than 1.8V and core current is less than 500uA. The simulation experiments showed that the conversion gain, IIP3, and power consumption were -1dB, 4.46dBm, and 0.8mW, respectively.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.370-370
• /
• 2011

ZnO 나노 라드 위에 Quantum dot을 형성하고 최종적으로 TiO2를 Atomic Layer Deposition방법으로 증착하여, 그 passivation 효과가 solar cell의 효율에 미친 영향에 대한 실험을 진행하였다. 암모니아 솔루션을 이용한 Hydrothermal 방법으로 수직한 1차원 형태의 ZnO 나노라드를 TCO 기판 위에 성장시킨다. 여기에 잘 알려진 SILAR와 CBD 방법으로 CdS, CdSe 양자점을 증착한다. 그리고 amorphous TiO2로 표면을 덮는 과정을 거치는데, TiO2가 좁은 간격으로 형성된 ZnO라드 구조 위에서 균일하고 정밀하게 증착되도록 하기 위해 Atomic Layer Deposition을 이용하였다. 사용된 precursor는 Titanium isopropoxide와 H2O이며, 실험상에서 0~5 nm 두께의 TiO2 박막을 형성해 보았다. 다양한 분석 방법을 통해 TiO2/QDs/ZnO의 shell-shell-core 구조를 조사했다. (Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS)). 이를 solar cell에 적용하고 I-V curve를 통해 그 효율을 확인하였으며, Electrochemical Impedance Spectroscopy (EIS)를 통해서 재결합 측면에서 나타나는 변화 양상을 확인하였다.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.19 no.2
• /
• pp.211-217
• /
• 2016

The fuel cell based auxiliary power unit (APU) is promising for power source of armed vehicles due to its silence and high efficiency. Especially, the on board hydrogen generation and fed to fuel cell system was core technology of this power system. In this study, we analyzed the performance of the Auto thermal reactor (ATR) that produce the hydrogen from the fuel, integrated High temperature polymer electrolyte fuel cell (HT-PEFC) by Aspen plus software. The fuel was designed as a n-dodecane for analysis of military fuel (JP-8).

• The Korean Journal of Cytopathology
• /
• v.2 no.1
• /
• pp.43-50
• /
• 1991

A case of malignant epithelial mesothelioma of the peritoneum diagnosed by fine needle aspiration cytology is described. The smear showed many Individually scattered or clustered large round malignant epithelial cells intermingled with relatively small nonneoplastic mesothelial and mesenchymal cells. Papillary configurations with thick fibrous core were also seen. The malignant cells were virtually reminiscent of reactive mesothelial cells but they were larger in size and had more prominent nucleoli and more frequent binucleated or multinucleated cell formations than reactive mesothelial cells. The characteristic features of malignant cell of mesothelioma compared with the metastatic adenocarcinoma were relatively uniform cellular size, prominent round nucleoli, large round vesicular nuclei with finely granular chromatin pattern, smooth nuclear membrane, abundant glassy cytoplasm rather than bubbly mucin-containing cytoplasm and fuzzy cell border.

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2003.10b
• /
• pp.168-168
• /
• 2003

The acetylation of histone is one of the mechanisms involved in the regulation of gene expression and is tightly controlled by two core enzymes, histone acetyltransferase (HAT) and deacetylase (HDAC). There are several reports that imbalance of HAT and HDAC activity is associated with abnormal behavior of the cells in morphology, cell cycle, differentiation, and carcinogenesis.(omitted)