• Journal of Forest and Environmental Science
• /
• 제34권1호
• /
• pp.61-65
• /
• 2018

To know if small changes in rearing water temperature and density affect the number of bacterial and fungal colonies in metamorphosed frogs, Dybowski's frog tadpoles were reared from Gosner 25-26 stages at either low ($1^{\circ}C$ low to ambient water temperature), ambient, or high ($1^{\circ}C$ high) water temperature (each 15 tadpoles in 20 L water) condition and at either low (10 tadpoles/20 L water), medium (20 tadpoles), or high (30 tadpoles) density condition. Immediately after metamorphosis, we sampled bacteria and fungi from skin, liver, and heart of six metamorphosed frogs, randomly selected for each treatment group. After separate incubation of bacteria and fungi on 3M Petrifilm plates, we counted the number of bacterial and fungal colonies appeared on the plates and compared the numbers among the temperature and density treatment groups. For temperature treatment, high-temperature group had fewer bacterial colonies, while low-temperature group had more fungal colonies than the other two groups. For density treatment, low-density group had fewer bacterial colonies than the other two groups, but the number of fungal colonies were not different among the groups. Our results suggest that small increased rearing water temperature and lowered rearing density could potentially reduce pathogens in farming frogs.

• 한국분무공학회지
• /
• 제8권2호
• /
• pp.7-15
• /
• 2003

The effects of fuel density and fuel viscosity on spray characteristics were investigated under two different gas turbine fuels and various fuel supply pressure conditions through measurement of SMD, number density and volume flux by using PDPA system in dual orifice injector for gas turbine engines. In this study, we found out that the droplet size and spray structure are strongly depend on fuel density for dual orifice injector. The spray characteristics of high density fuel in dual orifice injector are similar with the characteristics of low density fuel in single orifice injector. The shear region between primary main fuel stream and secondary main fuel stream is examined in low density fuel condition but not exist in high density fuel condition, then this shear region is very important in quality of gas turbine spray. There are worth consideration for the effect of fuel density on spray characteristics in frontal device design to improve combustion efficiency.

• 생약학회지
• /
• 제15권4호
• /
• pp.206-212
• /
• 1984

The effect of saponin fractions of Panax ginseng root on the interactions of human plasma lipoproteins and lecithin dispersions with dextran sulfate were studied in order to examine the effect of Panax ginseng on the lipid accumulation in the aorta. The total saponin fraction and protopanaxadiol glycosides of Panax ginseng root seemed to slightly enhance the interaction of low density lipoproteins with dextran sulfate in the absence of divalent metal ions. Protopanaxatriol glycosides remarkably inhibited the interaction of low density lipoproteins with dextran sulfate. However, all of these three saponin fractions of Panax ginseng root showed the tendency of inhibition to the interaction of high density lipoproteins with dextran sulfate in the presence of divalent metal ions by the order of protopanxatriol glycosides, protopanaxadiol glycosides and total saponin. Three saponin fractions of Panax ginseng exerted almost same tendency to the interaction of lecithin dispersions with dextran sulfate in the presence of divalent metal ions as the interaction of low density lipoproteins with dextran sulfate absence of divalent metal ions.

• 한국식품영양학회지
• /
• 제17권2호
• /
• pp.138-146
• /
• 2004

본 연구는 유용식물로부터 DPPH free radical scavenger및 사람의 low density lipoprotein(LDL)의 산화에 대한 항산화 효과를 조사하기 위하여 25종의 식물로부터 메탄올로 추출하여 조사하였다. 각종 유용식물 중 항산화 활성은 우수한 달맞이꽃이 가장 높았으며 다시 메타놀로 추출하여 조사한 결과 $\alpha$-tocopherol과 항산화능이 거의 비슷하였다. 메타놀 추출물을 ethylacetate로 추출한 획분이 항산화 활성이 높았으며 ethylacetate 층 중 acidic soluble 획분을 다시 분리한 후 Sepadex LH-20 column chromatography로 추출한 결과 Fraction F-2가 전자공유능이 가장 높았다. 따라서 항산화 활성이 높은Fraction, F-2의 구조를 동정한 결과 3,4-dihydroxybenzoic acid와 3-hyoxycinnamic acid로 확인되었다.

• 폴리머
• /
• 제25권6호
• /
• pp.840-847
• /
• 2001

메탈로센 촉매로 제조된 메탈로센 선형 저밀도 폴리에틸렌(m-LLDPE)과 Ziegler-Natta 촉매에 의하여 제조된 선형 저밀도 폴리에틸렌(LLDPE) 블렌드의 결정화 거동을 고찰하여 보았다. 특히 블렌딩이 이들의 결정화 induction time 및 구정성장 속도 그리고 최대 구정의 크기에 미치는 영향을 중점적으로 살펴보았다. LLDPE/LDPE 블렌드와는 달리 LLDPE에 m-LLDPE를 블렌딩할 경우, 각각의 결정 형성 대신 하나의 결정이 형성됨을 확인하였으며 induction time이 현저히 짧아짐을 알 수 있었다. 하지만 이러한 감소는 블렌드의 조성비에는 크게 영향을 받지 않았다. 또한 블렌딩에 의하여 LLDPE의 구정성장 속도가 증가함을 확인할 수 있었으며, 구정의 최대 크기는 induction time과 구정성장 속도가 LLDPE에 미치는 영향에 따라 달라짐을 알 수 있었다.

• Journal of Communications and Networks
• /
• 제16권6호
• /
• pp.639-644
• /
• 2014

In low-density parity-check (LDPC) coded multiple-input multiple-output (MIMO) communication systems, probabilistic information are exchanged between an LDPC decoder and a MIMO detector. TheMIMO detector has to calculate probabilistic values for each bit which can be very complex. In [1], the authors presented a class of linear block codes named low-density MIMO codes (LDMC) which can reduce the complexity of MIMO detector. However, this code only supports the outer-iterations between the MIMO detector and decoder, but does not support the inner-iterations inside the LDPC decoder. In this paper, a new approach to construct LDMC codes is introduced. The new LDMC codes can be encoded efficiently at the transmitter side and support both of the inner-iterations and outer-iterations at the receiver side. Furthermore they can achieve the design rates and perform very well over MIMO channels.

• 생명과학회지
• /
• 제9권1호
• /
• pp.99-105
• /
• 1999

Bacillus sp. RH-5로 배양한 배양액을 silica gel column (8.0cmX100cm)chromatography를 행하여 chloroform : methanol = 90 : 10인 항산화 분획층을 얻어 TLC 법에 의해 활성이 있는 물질을 분리하여 thiocyanate method로 활성을 측정하여 본 결과 Vit. E($10^{-2}$ mol)보다 좋았으며 BHA, BHT와는 비슷한 결과를 나타내었다. 한편 $5_\muM$ $CuSO_4$ 촉매 사람 Low Density Lipoprotein(LDL)의 산화에 항산화 활성이 알려진 Fraction 3의 band 4를 각각 100 및 200$\mu$g/$m\ell$ 농도로 $37^{\circ}C$에서 18시간 배양한 결과 LDL의 산화에 대한 억제효과가 좋았다. Fraction 3의 band 4를 HPLC로 정제한 후 IR. NMR 및 GC/MASS.로 확인한 결과 5-hydroxyndole로 확인되었다.

• Journal of Periodontal and Implant Science
• /
• 제23권1호
• /
• pp.16-26
• /
• 1993

In order to investigate the healing effect on inflammation and bone regeneration of low power density laser radiation in dogs, experimental periodontitis was made in dog mandibular 3rd, 4th premolars. All teeth were classified with four groups of two experimental group and control groups. The second group were irradiated on periodontitis site and the first group were control. The fourth group were irradiated on periodontitis site flap operation and the third group were flap control. Experimental groups were irradiated with GaAs low power density laser of pulse wave and continuous wave of 904nm every day by five days respectively and then control group and experimental groups were evaluated by histo-pathological study. The results were as follows : 1. Experimental periodontits site of dog were irradiated with GaAs low power laser results in reducing of pseudoepitheliomatous proliferation and inflammation at light microscope. 2. After irradiation with low power density laser, experimental groups were revealed that PDL forming activity were increased and newly formed collagen deposition were observed. 3. Low power density lsaer irradiation on experimental periodontits site after flap operation showed that decreasing of inflammation, reducing of osteoclast activity. Capillary proliferation, reduction of pseudoepitheliomatous proliferation. 4. After irradiation with low power density laser on flap experimental site, experimental groups were revealed that newly formed collagen in periodontal ligament and alveolar bone were detected on MT staining.

• 동력기계공학회지
• /
• 제21권1호
• /
• pp.43-49
• /
• 2017

This work aims to investigate on the low cycle fatigue life assessment, which is adopted on the strain-life relationship, or better known as the Coffin-Manson relationship, and also the strain energy density-based model. The low cycle fatigue test results of Alloy 617 weldments under $900^{\circ}C$ have been statistically estimated through the Coffin-Manson relationship according to the provided strain profile. In addition, the strain energy density-based model is proposed to represent the energy dissipated per cycle as fatigue damage parameter. Based on the results, Alloy 617 weldments followed the Coffin-Manson relationship and strain energy density-based model well, and they were compatible with the experimental data. The predicted lives based on these two proposed models were examined with the experimental data to select a proper life prediction parameter.

• 한국주거학회:학술대회논문집
• /
• 한국주거학회 2009년도 추계학술발표대회 논문집
• /
• pp.263-267
• /
• 2009

Recently, we have seen the change of population and family structure, population growth has slowed and family differentiation was constantly done. A rapidly increase of single and couple household. So small-scaled house demand will be increased. Therefore this study planned to solve recent collective housing problem and to satisfy new housing demand. The purpose of planning was that low-rise high-density small-scaled of urban housing complex. This study used for two methods. First methods were literature analysis for domestic collective houses's present conditions and issues. Other purpose was to confirm change of household. Second method is case studies. It went through two phases to select the cases. The cases selected domestic and foreign each eight, total sixteen. The cases analyzed to twelve elements characteristic of housing complex, unit and community facilities. This study applied one area of Seoul to the low-rise high-density small-scaled housing complex.