• Biomolecules & Therapeutics
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• v.5 no.1
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• pp.1-7
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• 1997

This study was done to investigate the effect of vitamin C on hypoxia/reoxygenation-induced hepatic injury ul isolated perfused rat liver. Isolated livers from rats fasted 18 hours were subjected to 45 min of hypoxia followed by reoxygenation for 45 min. The perfusion medium used was Krebs-Henseleit bicarbonate buffer (pH 7.4) and 0.5 mmol/L of vitamin C was added to the perfusate. Alanine aminotransferase (ALI) and lactate dehydrogenase (LDH) levels were significantly increased by hypoxia/reoxygenation. These increases were augmented by vitamin C. Glucose output and bile flow were markedly decreased by hypoxia/reoxygenation. Vitamin C aggavated the decrease of glucose output but had little effect on bile flow. Our findings suggest that hypoxia/reoxygenation diminishes hepatic metabolic and secretory functions, and vitamin C significantly aggravates these changes.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.165-175
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• 2000

In order to improve the function of a door seal, its section design technique is discussed in this study, Its roles are prevention of an inflow of dusts, noise interception, insulation, wateproof, and the vibroisolating action which reduces vibration between the body and the door of a car while running, and the buffer action which sustain the proper reacting force as the door is closed. In this study, the optimal cross section of a door seal is designed using nonlinear finite element analysis (commercial finete element analysis program EASi-SEAL) and tables of orthogonal arralys with respect to relations between door and door seal to secure the satisfactory airtight property with the minimum force to shut the door.

• IE interfaces
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• v.4 no.1
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• pp.63-69
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• 1991

In this paper, the Go-Back-N ARQ protocol with decoding in communication network is considered. The time delay and throughput are respectively analyzed as a function of window size and decoding time out. Packets arrive continuously at the decoder, and are stored in a buffer if the decoder is busy upon its arrival. The decoder devotes no more than a time-out period of predetermined length to the decoding of any single packet. If packet decoding is completed within that period, the packet leaves the system. Otherwise, it is retransimitted and its decoding starts anew. The time delay and throughput are obtained using recursive formula and difference equation. An appropriate time out and window size that satisfies the grade of service can be determined.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1237-1240
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• 1996

This paper proposes a heuristic algorithm for performing the line balancing of PCB assembly fine including multiple surface mounters efficiently. We consider a PCB assembly line including the multiple surface mounters arranged serially as a target system. We assume that the number of heads of surface mounters can be changed. Also, the conveyor is assumed to move at a constant speed and have no buffer. Considering the minimum number of machines required for the desired production rate is a discrete nonincreasing function which is inversely proportional to the cycle time, we propose an optimization algorithm for line balancing by using the binary search method. Also we propose an head-changing algorithm. The algorithms are validated through the computer simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.9 no.4
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• pp.153-156
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• 1984

A local area network(LAN) controller is designed according to non-persistent CSMA protocols. By meas of a buffer register, a microcomputer interfaces with the LAN controller. To keep bus utilization near the optimal efficiencies, the transmission intervals are adjusted as a function of $2^n$. A message in the form of a packet consisting of 128bytes is transitted to the bus. The maximum transmission rate of 19.2Kbps is obtained at layer 1.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.531-534
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• 2002

NiO buffer layers for YBCO coated conductors were deposited on hi-axially textured Ni substrates by MOCVD(metal organic chemical vapor deposition) method, using single solution source. To establish the processing condition, oxygen partial pressure and deposition temperature were changed. The surface orientation and degree of texture were estimated by X-ray diffraction, X-ray pole figure and atomic force microscopy. The FWHMs of in-plane and out-of-plane of the NiO films were about 10$^{\circ}$. The surface roughness was a function of deposition temperature. The AFM surface roughness of NiO films is in the range of 3∼10 nm, when NiO films was grown at 450∼530$^{\circ}C$.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.620-626
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• 1988

GaAs solar cells may be the most attractive and efficient power source of a satellite. GaAs is more radiation tolerant and less temperature sensitive than widely used silicon. $Al_{x}$ Ga$_{1-x}$ As/GaAs solar cells have been designed and fabricated by Liquid Phase Epitaxial method. GaAs solar cells, of which structure is about 0.2 .mu.m p$^{+}$ - window layer, 0.6-1.O .mu.m Ge-doped p-layer. 3.mu.m n-GaAs layer and n$^{+}$ - buffer layer, have been characterized as a function of operating temperature from 25 .deg.C to 130 .deg.C. Open circuit voltage decreases linearly with increasing temperature by 1.4-1.51 mV/ .deg.C while degradation of silicon solar cells is about 2.2-2.5 mV/ .deg.C, short circuit current does not increase much with increasing temperature. Relative efficiency decreases with increasing of temperature by about 0.21-0.29 %/ .deg.C. Efficiency degradation of silicon solar cells with temperature is known to be about 0.5%/ .deg.C and our results show GaAs solar cells may be an excellent candidate for concentrated solar cells.ells.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.506-511
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• 1996

The performance evaluation of flexible manufacturing systems or cells at the stages of design and planning is one of important issues in manufacturing. For that reason, Guo has presented an approachbased on moment generating function and generalized stochastic PetriNets for performance analysis. In this paper, Buo's approach is extended tothe cases of flexible manufacturing cell including one machining center with a local buffer, AS/RS(Automatic Storage and Retrieval System), set-up station and AGV(Automated Guided Vehicle). Then the performance measures from this approach is compared with simulation. The major advantage ofthis method over existing performance evaluation methods is the ability to compute analytic solutions for performance measures.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.92-98
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• 2000

A ring comprising a coated conductor was fabricated. A ring was made first using a biaxially textured Ni tape whose two ends were connected by means of the atomic diffusion bonding technique. Then buffer layers and a YBCO film were deposited on it. All the films were well textured as confirmed by XRD pole figures. The B-H loops, where B and H are the magnetic field at the center of the ring and the applied field respectively, were measured as a function of temperature. The persistent current density (J$_c$) flowing circularly was estimated from the remanent field of B. In the range of temperature from 72K to 20K, J$_c$ changed from zero to 2${\times}$1 0$^5$A/cm$^2$.

• Journal of the Korean housing association
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• v.1 no.1
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• pp.27-35
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• 1990

In the course of modernization coupled with industrialization and urbanization. Maru or wooden floor and Teachong or great hall of Han-ok or traditional Korean housing has experienced functional as well as physical changes to a remarkable degree. The author made an analysis of the transfiguration of Maru/Taechong space(M/T) with relation to: 1)Madang or yard. 2)Anbang or inner room, 3)Hyon-kwan or vestibule. 1) In relation to Madang, interiorization of M/T by way of setting sliding glass doors has begun to appear. 2) In connection with Anbang, division of role/function is being observed as far as family entertainment and reception of intimate friends is concerned. 3) Owing to wider acceptance of Hyon-kwan space as a buffer zone system, the advent of Keo-sil or living room is thought to be facilitated. The analysis, however, does not say that Keo-sil of modernized Korean housing might well be interpreted as the mere extension type of M/T of the vernacular housing.