• Analytical Science and Technology
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• v.12 no.1
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• pp.75-79
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• 1999

The concentration of polyamine and the relationship between the concentration of PA and cold resistance were analysed during the cold stress in the cotyledons and hypocotyls of young spring radishes. The concentration of PUT was increased during the cold stress in the cotyledons and the concentration of PUT and SPD was changed significantly all the stress time. From the results, we suggested that PUT and SPD were synthesized against cold stress or separated from the bound PA during the cold stress. But, the concentration of SPM was not significantly changed during the cold stress. Only SPD existed in the control hypocotyls. The concentration of SPD was increased during the cold stress, but was decreased dramatically during continusly cold stress. The reactivity against stress of hypocotyls was generally more sensitive during the cold treatment than that of the cotyledons because of the lower concentration of PA in the hypocotyls. PUT and SPD were responsible for the resistance of cold stress in the cotyledons and PA did not play an important role on the resistance of cold stress in the hypocotyls. In this study we suggest that PUT and SPD were responsible for the increase of the resistance against the cold stress.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10A
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• pp.896-905
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• 2005

In this paper, we propose a SPD(Selective Packet Delay) scheme to improve the performance of High-Speed Downlink Shared Channel(HS-DSCH) employing N-Channel Stop and Wait retransmission scheme in High Speed Downlink Packet Access(HSDPA) system. The proposed SPD coordinates packet transmissions according to the channel condition. When the channel condition is bad, packet transmission is forcedly delayed, and the designated time slot is set over to other users in good channel condition. Hence, the SPD is able to reduce the average transmission delay for packet transmission under the burst error environments. In addition, we propose two packet scheduling schemes called SPD-LDPF(Long Delayed Packet First) and SPD-DCRR(Deficit Compensated Round Robin) that are effectively combined with the SPD scheme. Simulation results show that the proposed scheme has better performance in terms of delay, throughput and fairness.

• The Journal of Pediatrics of Korean Medicine
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• v.11 no.1
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• pp.205-226
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• 1997

Sanpoongdan(SPD) has been known effective on infantile convulsive disorders in clinical field of oriental medicine. The purpose of this study was to investigate the anti-convulsive, sedation and analgesic effects of SPD in mouse. The anticonvulsive effect was evaluated In mice treated with pentylenetetrazol, stychnine, and picrotoxin. For the sedative effect, observations were made on the sleeping time induced by thiopental sodium and pentobarbital sodium following oral administration of SPD. Furthermore, reduction of spontaneous movements and ataxia using rota rod method were evaluated. Analgesic effects on the writhing syndrome induced by acetic acid and on hindlimb pain induced by pressure were also observed. The findings were as follows : 1. The solid extracts of SPD revealed no effect on convulsions induced by pentylenetetrazol, strychnine, and picrotoxin. 2. Thiopental sodium-induced sleeping time was prolonged by the administration of the solid extracts of SPD, but this result was devoid of statistical significance. 3. The oral administration of SPD enhanced the sleeping induced by pentobarbital sodium. 4. Spontaneous movements were significantly depressed following the oral administration of the solid extracts of SPD. 5. Ataxia was not shown in rota rod method following the oral administration of the solid extracts of SPD. 6. The solid extracts of SPD showed positive analgesic effects on the acetic acid-induced writhing syndrome. 7. The solid extracts of SPD raised the threshold of the hindlimb pressure pain, but the result was not statistically significant. From the results, it can be concluded that SPD has sedative and analgesic effects.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.3
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• pp.328-333
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• 2009

In this paper, we have developed high performance SPD(surge protective device) and evaluated the characteristics in comparison with typical SPD used in the inside and outside of the country. The new SPD was composed of MOV(metal oxide varistor), GDT(gas discharge tube) and impedance such as resistors, capacitors or varistors. To estimate operating the characteristic of the SPD which was developed, it was measured surge voltage caused by fault current or surge according to IEC 61000-4-5. As a result it was found that the power supply was cut off by high performance SPD when caused a short-circuit. In addition we could know that it could prevent ELB(earth leakage breaker)'s malfunction caused by surge.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.609-610
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• 2012

서지로부터 전기기기, 전자통신기기 등을 보호하기 위하여 설치하고 있는 SPD가 본연의 목적을 달성하지 못하고 소손되는 경우가 있다. 이와 관련 하여 SPD 특성을 이해하고, 서지보호에 효율적으로 대처하기 위한 SPD 선정방안을 제시하고자 한다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1592-1593
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• 2011

전 세계적으로 전력사용량의 증가와 전력기술이 발전함에 따라 절연소재 또한 급속한 발전을 가져왔다. 특히 폴리머 애자는 경량성, 내오염성, 시공의 용이성 등과 같은 장점으로 오랫동안 사용해온 자기 애자를 대체하여 사용되고 있다. 최근 고효율 장거리 전력 송전이 가능한 HVDC 송전선로가 증가함에 따라 직류 절연물에 대한 연구가 활발히 이루어지고 있다. 본 연구에서는 두 종류의 실리콘 베이스와 첨가제 함량을 변화시킨 폴리머 시편의 직류 파괴전압 실험과 교류 파괴전압 실험을 실시하였다. 취득한 데이터를 Weibull 분포를 통해 분석 한 결과 직류 파괴전압이 교류 파괴전압에 비해 2~5배 높은 것으로 나타났다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.66-71
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• 2003

Electronic equipments made from integrated circuits and small-sized semiconductors is protected by surge protective devices(SPDs) such as ZnO varistors, Zener diode and gas discharge tube from lightning overvoltages. However the clamping voltage of SPDs is greatly influenced by the method of installing the SPDs. In this paper, the protective effects of SPDs according to types of system groundings were experimentally investigated. The separate grounding is a particularly undesirable way to install SPDs. The effectiveness of the common grounding point for ZnO varistors is more pronounced than that for gas discharge tubes. The common grounding at the terminal of SPDs is recommended as a best method of installing SPDs.

• The Korea Journal of Herbology
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• v.27 no.5
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• pp.15-20
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• 2012

Objectives : The purpose of this study was to estimate the antioxidant activity of water extract of Nelumbinis stamen (WNS) in GC-2 spd (ts) cells. Methods : we investigated the effect of WNS in mouse GC-2 spd (ts) cells by MTT assay. The protective effects of WNS against hydrogen peroxide-induced oxidative stress in GC-2 spd (ts) cells were examined by measuring cell viability. Lipid peroxidation levels and catalase were measured. Results : WNS showed cell viability as 101.9, 108.9, 111.8, 125.8, 134.5% in 2.5, 5, 10, 25, 50 ${\mu}g/ml$ concentrations, respectively. The protective effect of WNS concentration was 2.5 ${\mu}g/ml$ against hydrogen peroxide-induced oxidative stress in GC-2 spd (ts) cells. LPO were decreased significantly at 2.5, 5, 25 ${\mu}g/ml$ of WNS concentrations. Catalase activity was significantly increased at 2.5, 5 and 10 ${\mu}g/ml$ of WNS concentrations, respectively. Conclusions : In conclusion, WNS has antioxidant activities in GC-2 spd(ts) cells against oxidative stress.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2643-2646
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• 2009

In this study, a novel phosphorus-containing flame retardant copolymer of spirocyclic pentaerythritol di(phosphate monochloride) and bisphenol S (SPD-BS) was successfully synthesized and used as a flame retardant in diglycidyl ether of bisphenol A (DGEBA) epoxy resins. The chemical structure of the SPD-BS was characterized using FT-IR and $^1H$ NMR spectra. The thermal properties were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The effects of SPD-BS and nano-$CaCO_3$ on the flame-retardant properties of DGEBA/SPD-BS systems were evaluated by measurement of the burning rate. As a result, the thermal stabilities of the DGEBA/SPD-BS systems were decreased with increasing SPD-BS content. The flame-retardant properties and char yields of the systems were significantly increased when SPD-BS content increased. The synergism of nano-$CaCO_3$ incorporation on flame retardancy was found for the DGEBA/SPD-BS systems.

• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.587-599
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• 2000

This study was conducted to observe the severity of the disease and pathogenecity of Babesia gibsoni parasite on the splenectomized dogs(SPD) and nonsplenectomized(intact) dogs (NSPD) experimentally infected with B gibsoni. The average prepatent period was 4 days in the SPD and 8 days in the NSPD, respectively. Peak parasitaemia(PE) ranged from 26% to 34% of erythrocytes infected in the SPD and from 4% to 5% in the NSPD. Latent parasitaemia was still detectable 40 days as low as under 1.0% of erythrocytes infected after the initial parasitaemia in the SPD. Blood packed cell volume(PCV) decreased to as little as 6.4% to 6.9% in the SPD. The clinical signs were mild fever and anemia in the NSPD, remissions and exacervations of temperature, intermittent or spike-like increases of temperature, progressive polychromatophilic macrocytic anemia with anisocytosis, icterus, marked loss of appetite, rarely haemoglobinuria, and deep brown-yellowish urine in the SPD. Gross pathologic changes mainly involved slightly enlargement of liver and spleen in the NSPD and marked enlargement of liver in the SPD. Anatomic changes associated with the disease included diffuse periportal and centrilobular hephatitis, and membranoproliferative glomerulonephritis. Hyaline droplets, resulting protein metabolic alterations, were found in the convoluted ephithelium of the kidney. The density of lymphocytes within the liver sinusoids was markedly increased. Aggregates of large monocytes and macrophages were demonstrated in the centrilobular veins of the liver. The density of these cells in the centrilobular veins were greatest in the SPD. The forms of B gibsoni parasite found in the acute stage of SPD were large signet ring form, small signet ring form, pyriform, elongated form, comma form, head-phone form, oval form, peared form, racket-like form, amoeboid form, triangle form, quartered form, dot form, band form and multiple, and rosette form, et al. The severity of the disease and pathogenecity of B gibsoni parasite were mild in the NSPD but fatal in the SPD.