• 제목/요약/키워드: aggregation ratio

검색결과 117건 처리시간 0.024초

대형주강 압탕부의 편석거동 고찰 (Investigation of Segregation Behavior in the Riser/Castings Junction of Heavy-section Steel Castings)

  • 김지태;박흥일;김우열;이병우
    • 한국주조공학회지
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    • 제30권4호
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    • pp.130-136
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    • 2010
  • Sulfide segregation behavior, characteristics of solidification microstructure and compositional distribution in the riser/castings junction of heavy-section main bearing support (MBS) steel castings were investigated; Sulfide streaks of A segregation were formed in the transitional region from columnar grain to coarse equiaxed grain and floated with aggregation of the dendritic free crystal. Solute segregation behaviors of elements Si, P and S were V shape negative segregation from the bottom of the castings to upper part of the riser with the reference of vertical center-line of the specimen block. Those of elements C and Mn were V shape negative segregation in the main body and A shape positive segregation in the riser of the casting. Just beneath the pipe shrinkage in the riser segregation ratio of each element was the highest, and that of S was 3.6 times higher, C 3.3 times, P 2.1 times, Si 1.6 times and Mn 1.0 times respectively. [Mn/S] ratio of the specimen block was distributed in the wide range of 20~275.

Genetic Epidemiological Analysis of Esophageal Cancer in High-incidence Areas of China

  • Wang, Kai-Juan;Yang, Jun-Xia;Shi, Jia-Chen;Deng, Song-Yuan;Cao, Xiao-Qin;Song, Chun-Hua;Wang, Peng
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권22호
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    • pp.9859-9863
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    • 2014
  • Genetic epidemiological studies have shown that genetic susceptibility to esophageal cancer (EC) is an important cause of its high incidence within families in some areas of China. The purpose of this study was to obtain evidence of a genetic basis of EC in Xin-an and Xin-xiang counties in China. Familial aggregation and complex segregation analyses were performed of 79 EC families in these counties. The heritability of EC was examined using Falconer's method and complex segregation analysis was conducted with the SEGREG program in Statistical Analysis for Genetic Epidemiology (SAGE version 5.3.1). The results showed that the distribution of EC in families did not fit well into a binomial distribution. The heritability of EC among first-degree and second-degree relatives was $67.0{\pm}7.31%$ and $43.1%{\pm}9.80%$, respectively, and the summing up powered heritability was $53.2{\pm}6.74%$. The segregation ratio was 0.045. Complex segregation analysis showed that the genetic model of EC was additive. The current results provide evidence for an inherited propensity to EC in certain high-risk groups in China, and support efforts to identify the genes that confer susceptibility to this disease.

패킷취합전송이 있는 MANET에서 IDS 성능 (IDS Performance on MANET with Packet Aggregation Transmissions)

  • 김영동
    • 한국전자통신학회논문지
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    • 제9권6호
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    • pp.695-701
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    • 2014
  • 블랙홀 공격은 라우팅 정보를 무단으로 변경하여 전송성능에 치명적인 영향을 초래할 수 있다. 블랙홀 공격에 대응하는 수단으로서 IDS(Intrusion Detection System) 또는 IPS(Intrusion Prevention System) 등을 사용할 경우 일정 정도의 전송성능을 개선할 수 있다. 본문에서는 블랙홀 공격이 발생되는 MANET(Mobile Ad-hoc Network)에서 IDS가 종단간 성능에 미치는 영향을 패킷취합전송 관점에서 분석한다. 성능분석은 NS-2를 기반으로 구축한 MANET 시뮬레이터를 사용하였으며, 음성 서비스인 VoIP(Voice over Internet Protocol) 트래픽을 대상으로 음성서비스 표준 성능 파라미터인 MOS(Mean Opinion Score), 연결율, 지연 및 패킷손실율을 분석하였고, 본 논문에서 제시한 성능팩터를 활용한 분석을 제시하였다. 성능분석 결과의 하나로 패킷취합전송을 사용하는 MANET에서 블랙홀 공격에 대비한 IDS 조건을 제시하였다.

동물 및 인체시험을 통한 Nattokinase의 항응고 작용 및 섬유소 용해능 평가 (Evaluation of Nattokinase for Antithrombotic Effect and Pharmacological Efficacy by a Biological Test and Clinical Trial)

  • 김재범;유철배;신현만;정준기;장형욱
    • KSBB Journal
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    • 제26권5호
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    • pp.393-399
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    • 2011
  • Bacillus subtilis natto producing high level of a fibrinolytic enzyme was selected and Ultra Nattokinase$^{(R)}$ was manufactured by fermentation and purification. It was performed the evaluation of the antithrombotic effect of Ultra Nattokinase$^{(R)}$ (20,000 FU/g) with rat blood plasma. The maximum aggregation (inhibition ratio) was 71% (0%), 69% (2.8%), 62% (12.7%), 16% (77.5%) and 9% (87.3%), respectively, in the order of 0, 5, 10, 50 and 100 mg/mL of Ultra Nattokinase$^{(R)}$ solutions. Ultra Nattokinase$^{(R)}$ had antithrombotic effect, which was associated with the suppression of collagen-induced platelet aggregation. Ultra Nattokinase$^{(R)}$ in the topic of the FDP (fibrinogen degradation products) in blood coagulation tests showed a significant increasing trend. And based on the daily record of meal 39 people of ITT (what ?) group consisted with 19 people of NP (what ?) group and 20 people of PN (what ?) group except four people, two people who took vitamin K affecting the experiment and two people who took alcohol, finding to be taken Ultra Nattokinase$^{(R)}$ showed an increase in the FDP value after four weeks. In addition, FDP value of 41 people of ITT group except two people having metabolic syndrome was increased by Ultra Nattokinase$^{(R)}$.

마이크로 에멀젼 방법을 이용한 CaWO4의 합성 (Synthesis of CaWO4 by a Microemulsion Method)

  • 유은경;허영덕
    • 대한화학회지
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    • 제52권2호
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    • pp.164-168
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    • 2008
  • 마이크로 에멀젼 방법으로 CaWO4 결정을 합성하였다. CTAB에 대한 H2O의 몰랄 농도비(w)를 변 화시켜서 다양한 크기와 형태의 CaWO4를 얻었다. w=5와 w=10일 때 각각 100 nm와 500 nm 길이의 타원형 CaWO4 결정을 얻었다. w=20일 때는 1 μm의 막대형 CaWO4 결정을 얻었다. w=30에서는 길이가 약 2~3 μm인 구형의 CaWO4 결정을 얻었다. CTAB에 대한 H2O의 몰랄 농도비가 증가 할수록 응집에 의해서 CaWO4 결정 의 모양은 타원형에서 막대형태를 거쳐서 구형으로 변했다.

Tetrapyrazinoindoloporphyrazine Langmuir-Blodgett Films

  • Kim, Jong-Min;Jaung, Jae-Yun;Ahn, Hee-Joon
    • Macromolecular Research
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    • 제16권4호
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    • pp.367-372
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    • 2008
  • We fabricated tetra(5-n-nonyl-8-tert-butyl-2,3-pyrazino[2,3-b]indolo)porphyrazinato copper(II) (Cu-Pc-$C_8$) Langmuir-Blodgett (LB) films. We further investigated the influence of arachidic acid (AA) as a transfer promoter, as well as the effect of dipping speed, on the deposition of the films on hydrophilic and hydrophobic substrates. In the case of pure Cu-Pc-$C_8$ LB deposition on a hydrophilic substrate, the transfer ratio was close to one for up-stroke depositions, but the previously deposited film was peeled off and re-spread onto water at down-stroke depositions. Whereas the stability of the Cu-Pc-$C_8$ LB films was not improved by AA addition on hydrophilic substrates, the deposition of Cu-Pc-$C_8$ was significantly improved by the presence of AA on a hydrophobic substrate. The AA-assisted deposition had transfer ratio of close to 1 and was essentially stable up to 10-layer depositions. Comparison of the UV-visible spectrum of a Cu-Pc-$C_8$/AA LB film with that of Cu-Pc-$C_8$/AA solution in dichloroethane revealed that the Soret and Q bands for the Cu-Pc-$C_8$/AA LB film were broadened and red-shifted due to the aggregation of phthalocyanines upon assembly in the LB film.

Dipalmitoyilphosphatidic acid와 지방산의 혼합 단분자 LB막의 혼합비에 따른 광이성질화 현상에 관한 연구 (Photoisomerization of monolayer LB Films of Dipalmitoyilphosphatidic Acid and Fatty Acid Mixture at difference Mixture Ratio)

  • 박근호;최성현
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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    • pp.943-946
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    • 2004
  • We have investigated to observe the photoisomerization using the mixture solutions in chloroform and LB monolayers mixed with DPPA and BASH containing azobenzene group which has reversible to cis-trans by light irradiation.. Spreading solutions for the LB films were Prepared in chloroform($5.0{\times}10^{-5}mol/L$). We investigated the photoisomerization and property of the organic ultra thin film of fatty acid containing azobenzene was Prepared on the glass plate by LB method. As a result, the absorption spectra of 8A5H and DPPA mixture of LB films was induced to photoisomerization by alternating irradiation of ultraviolet and visible light, because the condensation of pure azobenzene monolayers was loosened by the introduction of phospholipid into the monolayers, and the molecular high aggregation in pure azobenzene monolayers is also weakened by the introduction of phospholipid. We found that it was reversibly induced to cis-trans photoisomerization in a various mixture molar ratio.

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Shear-induced microstructure and rheology of cetylpyridinium chloride/sodium salicylate micellar solutions

  • Park, Dae-Geun;Kim, Won-Jong;Yang, Seung-Man
    • Korea-Australia Rheology Journal
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    • 제12권3_4호
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    • pp.143-149
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    • 2000
  • In this article, we considered shear-induced microstructure and rheological behavior of micellar solutions of cationic surfactant, cetylpyridinium chloride (CPC) in the presence of a structure-forming additive, sodium salicylate (NaSal). Shear viscosity, shear moduli and flow birefringence were measured as functions of the surfactant and additive concentrations. In the presence of NaSal, the micellar solution exhibited the non-linear rheological behavior due to the formation of supramolecular structures when the molar ratio of NaSal to CPC exceeded a certain threshold value. Flow birefringence probed the change in micelle alignment under shear flow. At low shear rates, the flow birefringence increased as the shear rate increased. On the other hand, fluctuation of flow birefringence appeared from the shear rate near the onset of shear thickening, which was caused by shear-induced coagulation or aggregation. These results were confirmed by the SEM images of in situ gelified micelle structure through sol-gel route.

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Rheological, Morphological and Electrical Properties of Polycarbonate/Multi-walled Carbon Nanotube Composites

  • Han, Mi-Sun;Sung, Yu-Taek;Chung, Ji-Woong;Kim, Woo-Nyon;Lee, Heon-Sang;Kum, Chong-Ku
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.220-220
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    • 2006
  • Rheological and electrical properties of the polycarbonate (PC) / multi-walled carbon nanotube (MWNT) were studied. The MWNT was funtoinalized by treating with the hydrogen peroxide ($H_{2}O_{2}$). The electrical conductivity showed higher value for the PC/MWNT ($H_{2}O_{2}$ treated, freeze drying) composites compared that of the PC/MWNT ($H_{2}O_{2}$ treated, thermal drying) composites. From the results of the morphological, rheological, and electrical properties of the PC/MWNT composites, it is suggested that the electrical and rheological properties of the PC/MWNT composites are affected by the MWNT-MWNT network structure which is related with the MWNT morphologies such as the degree of aggregation and aspect ratio of the MWNT.

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입자의 분산안정성이 고형오구의 세척성에 미치는 영향(제1보) - Nonyl Phenol Polyoxyethylene Ether 용액 내에서 α-Fe2O3 입자의 분산안정성 - (Effect of Dispersion Stability of Particles on Detergency of Particulate Soil(Part 1) - The Dispersion Stability of α-Fe2O3 Particles in the Nonyl Phenol Polyoxyethylene Ether Solution -)

  • 강인숙
    • 한국의류산업학회지
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    • 제4권1호
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    • pp.86-91
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    • 2002
  • To estimate dispersion stability of particles, suspending power and particle size were examined as functions of pHs, surfactants, electrolytes and ionic strengths using ${\alpha}-Fe_2O_3$ particle as the model of particulate soil. Suspending power and particle size were determined by UV-Vis spectrumeter and by light scattering using the polarization ratio method, respectively. The suspending power was relatively high with polyanion electrolytes and was low with neutral salts. The suspending power was biphasis, minimum pH 6~7, and the effect of surfactant on the suspending power was insignificant. Generally suspending power increased with decreasing the particle size governed aggregation of dispersed particles regardless of solution conditions. Hence the suspending power was inversely related to the particle size.