• Corrosion Science and Technology
• /
• v.21 no.4
• /
• pp.243-249
• /
• 2022

The objective of the present study was to perform failure analysis of double-layered bellow (expansion joint), a core part of stress reliever, used to relieve axial stresses induced by thermal expansion of heat-transport pipes in a district heating system. The bellow underwent tensile or compressive stresses due to its structure in terms of position. A leaked position sufferred a fatigue with a tensile component for decades. A cracked bellow contained a higher fraction of martensitic phase because of manufacturing and usage histories, which induced more brittleness on the component. Inclusions in the inner layer of the bellow acted as a site of stress concentration, from which cracks initiated and then propagated along the hoop direction from the inner surface of the inner layer under fatigue loading conditions. As the crack reached critical thickness, the crack propagated to the outer surface at a higher rate, resulting in leakage of the stress reliever.

• International Journal of Aerospace System Engineering
• /
• v.11 no.1
• /
• pp.1-3
• /
• 2024

Around the world, fossil fuel energy is being replaced with renewable energy due to environmental problems and sharp price increases. Many countries are making a change in the direction of moving toward eco-friendliness by reducing carbon emissions. Among renewable energies, the wind energy is eco-friendly because it produces electricity by wind power without carbon emissions, and it attracts attention worldwide as a great alternative to the exhausted fuel energy. To improve the efficiency of wind turbines, large and extra-large wind turbines have been developed all over the world by increasing install and diameter. These wind turbines have difficulty in transport after manufacture because of their size and height. Since the height of wind turbine blades is higher than the existing tunnel height, it is impossible to transport them. In this study, therefore, a 5 MW class large blade was separated for transport easiness as wind power generators became larger globally. Aerodynamic design and analysis was carried out for the blade. After performing structural design and analysis with the model designed, the stress concentration of the analyzed model and the various factors for consideration when separating were considered to conduct the study of selecting the optimal blade separation positions.

• Korean Journal of Veterinary Service
• /
• v.23 no.4
• /
• pp.361-366
• /
• 2000

The growth of bacteria on the surface of the meat was monitored to investigate the relationships between microbiological quality and some environmental factors such as the chilling temperature, alcohol spraying, and transport in slaughter process of pigs. The temperature changes of the surface and inner part of pork carcass were monitored with GreenTrack$\textregistered$ system during the process of chilling and transport Of the 100pigs tested, the prevalence of level on number of standard plate count (SPC) less than $10^4$ CFU/$\textrm{cm}^2$ and Escherichia coli less than $10^2$ CFU/$\textrm{cm}^2$ in pig were 82% and 80%, respectively. Suface bacterial numbers are decreased in the course of chilling process of the carcass. Alcohol spray process before packing meat also could decrease the surface bacterial count. In conclusion, this study could be overemphasized the importance of relationship between microbiological quality and refrigerating temperature in the process of refrigeration and cutting.

• The KIPS Transactions:PartC
• /
• v.16C no.6
• /
• pp.747-752
• /
• 2009

The AUTOSAR(AUTOmotive Open System ARchitecture) is an open software platform for automotive. The AUTOSAR contains the modules of FlexRay that is the next generation automotive network protocol. We have developed the modules including FlexRay State Manager, FlexRay Transport, FlexRay Interface, FlexRay Transceiver Driver and FlexRay Driver based on the standard of the module. This thesis presented not only the result of development but the result of design and implementation. And the developed modules were ported to the microcontroller board and verified.

• The KIPS Transactions:PartC
• /
• v.8C no.2
• /
• pp.198-206
• /
• 2001

· 21세기 도고 정보화 사회에서의 위성통신은 현존 위성 시스템에서 주로 제공하는 국가간 장 거리 전화, 방송 중계 서비스 등을 포함한 광범위한 대용량 디지털 멀티미디어 서비스 형태 의 트래픽을 처리하여 재분배하는 고성능, 다기능 정보통신으로 발전하고 있다. 이에 따라 전세계적으로 위성 수의 증가에 따른 위성궤도 부족과 주파수 자원의 고갈 등의 문제점을 야기시키게 되었다. 이를 해결하기 위해서는 기존의 단순 중계기의 역할뿐만 아니라, 위성탑 재 IF/RF 스위칭 기술, 기저대역 신호처리 기술, 다중 빔 안테나 기술 등을 포함한 OBP 탑 재 위성 시스템이 필요하게 된다. 따라서 본 논문에서는 기본적으로 멀티미디어 서비스를 제공하고 주파수 재사용 기법을 적용한 다중 스폿 빔을 송수신하는 차세대 OBP 탑재 위성 B-ISDN 중계망 접속 방식을 설계하고, 설계된 위성 B-ISDN 중계망 다중 접속 방식의 성 능을 평가하였다.

• BMB Reports
• /
• v.39 no.3
• /
• pp.335-338
• /
• 2006

Methylglyoxal (MG) is an endogenous physiological metabolite which is present in increased concentrations in diabetics. MG reacts with the amino acids of proteins to form advanced glycation end products. In this in vitro study, we investigated the effect of MG on the structure and function of ceruloplasmin (CP) a serum oxidase carrier of copper ions in the human. When CP was incubated with MG, the protein showed increased electrophoretic mobility which represented the aggregates at a high concentration of MG (100 mM). MG-mediated CP aggregation led to the loss of enzymatic activity and the release of copper ions from the protein. Radical scavengers and copper ion chelators significantly prevented CP aggregation. CP is an important protein that circulates in plasma as a major copper transport protein. It is suggested that oxidative damage of CP by MG may induce perturbations of the copper transport system and subsequently lead to harmful intracellular condition. The proposed mechanism, in part, may provide an explanation for the deterioration of organs in the diabetic patient.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.15 no.1
• /
• pp.71-83
• /
• 1997

In recent years, various kinds of organic photoreceptors have been used for copy machines based on electrophotography. Most of them are constructed into layered devices in which a photogeneration layer is separated from a charge transport layer. They are usually used with application of negative charges. Organic pigment have received considerable attention with phthalocyanine, squaraine, and azo compounds being used to construct zerograpgic photoreceptors with enhanced long wavelength sensitivity, residual potential and zerograpgic gain of squaraine photoconductor were measured from the photoinduced discharge curve. Most of synthesized squaraine derivative couldn`t use for CGM(charge generation material), but it knew that a part of one was able to use it within the possibility. A few appliance is used it know about dependence on CTM(charge transport material) of squaraine derivative. It could know that experiment`s result is 2.5-bis(4-N-N`-diethylaminophenyl)-1,3,4-oxadiazole(OXD) is the bestproduct.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.707-710
• /
• 2007

The sensor network by using Utrasonic transceiver is concerned about the dampness of the signals caused by distance among the nodes, the distortion for speed of data trasmission and the transport protocol. The motes are sized $50mm\times60mm$, the ultrasonic analog part sized $30mm\times40mm$ and record 2% error rate for data transport.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1997.04a
• /
• pp.249-252
• /
• 1997

Electroluminescence(EL) devices based on organic thin layers have attracted lot of interests because of their possible application as large-area display-emitting display. One of the problems of such devices is lifetime of the cell, where the degradation of the cell is partially due to the crystalliyzation of organic layers. In large part, this problem can be solved by using a multilayer device structure prepared by vapor deposition technique. In this study, blue light-emitting multilayer organic electroluminescence devices were fabricated vsing Poly (9-vinylcarbaEole) (PVK) and 2- (4-tert-butylphenyl)-5-(4$^{#}$-bis-phenyl) 1,3,4-oxadiazole (PBO) as hole trasport and electron transport material, respectively, where trim(8-hyd roxyquinolinate) aluminum (Al $q_3$) was used as a luminescenct material. A cell structure of glass sub- strate/indume-tin-oxide(ITO)/PCK/Al $q_3$/PBD/Mg:In was employed. Blue emission peak at 510nm was observed with this cell structure.e.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2009.01a
• /
• pp.49-54
• /
• 2009

Synchronization between media is an important aspect in the design of multimedia streaming system. This paper proposes a precise media synchronization mechanism for digital video and audio transport over IP networks. To support synchronization between video and audio bitstreams transported over IP networks, RTP/RTCP protocol suite is usually employed. To provide a precise mechanism for media synchronization between video and audio, we suggest an efficient media synchronization algorithm based on NPT (Normal Play Time) which can be derivable from the timestamp information in the header part of RTP packet generated for the transport of video and audio streams. With the proposed method, we do not need to send and process any RTCP SR (sender report) packet which is required for conventional media synchronization scheme, and accordingly could reduce the number of required UDP ports and the amount of control traffic injected into the network.