• 제목/요약/키워드: S-R variation

검색결과 941건 처리시간 0.027초

박동 혈액 순환 모의 시스템에서 시간 동기화된 혈압 및 혈액의 초음파 영상 측정 및 주기적 분석 (Time-synchronized measurement and cyclic analysis of ultrasound imaging from blood with blood pressure in the mock pulsatile blood circulation system)

  • 민수홍;김창수;팽동국
    • 한국음향학회지
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    • 제36권5호
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    • pp.361-369
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    • 2017
  • 뇌혈관 질환의 발생 및 진행 기작을 이해하고 그 질환의 조기진단과 진행예측을 위해서는 경동맥 분지에서의 혈류역학 정보가 매우 중요하다. 본 논문에서는 정상인 경동맥 분지 탄성 모형 혈관과 생체 외 돼지혈액을 이용하여 모의박동 혈액 순환 시스템을 구축하여 혈류를 조절하면서 혈관과 혈액의 초음파 영상을 내부 압력과 시간 동기화하여 측정하였다. 박동 펌프의 박동률이 분당 20회, 40회, 60회(r/min)일 때의 초음파 영상의 에코 값, 혈류속도, 혈관 벽의 움직임, 혈압을 펌프의 5주기 동안 평균하여 한 주기의 데이터를 추출하였다. 결과로 박동률이 20 r/min, 40 r/min, 60 r/min일때 수축기 최고 혈류 속도는 각각 20 cm/s, 25 cm/s, 40 cm/s, 혈압 차는 각각 30 mmHg, 70 mmHg, 85 mmHg, 동맥벽은 각각 0.05 mm, 0.15 mm, 0.25 mm로 확장 하였다. 에코의 주기적 변화는 혈류속도와 압력과는 시간 지연이 있었으며 20 r/min에서는 변화량이 최소였다. 이러한 시간 동기화된 인자들의 주기적 변화는 전산혈류역학 실험의 정확한 입력정보와 검증을 위한 중요한 정보이며 경동맥 협착 질환의 발생 및 진행 기작을 밝히는데도 유용한 정보를 제공할 것이다.

비닐아세테이트 코텔로머의 제조 및 계면활성(I) (Preparation and Surface-Active Properties of Vinyl Acetate Cotelomers (I))

  • 이언필;강세미;황대연;정영진;최해욱;최영호;이재호
    • 한국의류산업학회지
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    • 제14권4호
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    • pp.677-683
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    • 2012
  • 1-octanethiol and vinyl acetate telomers ($R_8S$-nVAc) were synthesized and hydrolyzed with sodium hydroxide subsequently, 1.2-epoxyhexane was then introduced to the telomers. In addition, we prepared cotelomers of multi-alkylated nonionic surfactants with a molecular structure of xRnMA-yVA (x; hydrophobic group, y; hydrophilic group, MA; methacrylic ester, VA; vinyl alcohol, R; and alkyl group) and cross-linked with sodium tetraborate decahydrate. Their active surface properties were investigated by several techniques such as surface tension, foaming property, and emulsification power measurements. The surface tension of $R_8S$-8.8VA decreased without the introduction of 1.2-Epoxy hexane, and the degree of emulsification and foaming abilities of $R_8S$-8.8VA increased without the introduction of 1.2-Epoxy hexane. However, the differences were insignificant. The epoxy groups were attached to a $R_8S$-8.8VA cotelomer with a limited variation of the active surface properties. The surface tension of $1.1R_6MA$-8.8VA decreased after cross-linking subsequently, the degree of emulsification and foaming abilities of $1.1R_6MA$-8.8VA increased after cross-linking. However, there was no clear difference between them. The B-O bonds were attached to a $1.1R_6MA$-8.8VA cotelomer with a limited variation of the active surface properties.

차체용 강판의 온도에 따른 변형률 속도 민감도 연구 (A study on the strain rate sensitivity according to the temperature for steel sheets of an auto-body)

  • 이희종;송정한;조상순;김석봉;허훈;박성호
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2005년도 추계학술대회 논문집
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    • pp.148-151
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    • 2005
  • This paper is concerned with the thermo-mechanical behavior and temperature dependent strain rate sensitivity of steel sheet for an auto-body. In order to Identify the temperature dependent strain rate sensitivity of SPRC35R and SPRC45E, uniaxial tension tests are performed with the variation of the strain rates from 0.001/sec to 200/sec, and the variation of environmental temperatures from $-40^{\circ}C\;to\;200^{\circ}C$. The thermo-mechanical response at the quasi-static state is obtained with the static tensile test and at the intermediate strain rate is from the high speed tensile test. The experimental results show that the strain rate sensitivity increases at low temperature and it decreases at high temperature. It means that as the strain rate getting increasing, the variation of flow stress is more sensitive on the temperature. The results also indicates that the material properties of SPRC35R is more depend on the changes of strain rates and temperature than those of SPRC45E.

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Systematic Studies on the Freshwater Goby, Rhinogobius Species (Perciformes, Geobiidae) III. Geographic Variation and Subspecific Differentiation in Rhinogobius giurinus, with a Comment on Genetic Relationships among Four Species of the Genus Rhinogobius in Korea

  • Kim, Jong-Bum;Kim, Jae-Heup;Yang, Suh-Yung
    • Animal cells and systems
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    • 제1권4호
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    • pp.529-534
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    • 1997
  • Genetic and morphological variations of Rhinogobius giurinus were surveyed. Populations of R.giurinus were clearly divided into two forms (Form-A and Form-B). Starch gel variation of this species. Three loci (Aco, Mpi, aGpd) out of 27 showed fixed allelic differences between Form-A and Form-B and they are well differentiated from each other genetically (Rogers' S=0.871). These two forms, moreover, are found to be allopatric in distribution and morphologi cally different in body length and caudal fin color pattern. Therefore, they are considered as two distinct taxa of subspecific rank. In addition, the genetic relationships among 5 taxa within 4 species of the genus Rhinogobius were investigated. Three species of the Rhinogobius brunneus complex (R.sp. OR, R. sp. CB and R. sp. CO) are well differentiated from each other genetically and two taxa of R. giurinus are genetically divergent from three species of the Rhinosotius brunneus complex (average Nei's D=0.603, average Rogers'=0.534).

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규모 5.8 경주 지진에 의한 토양 내 라돈농도의 이상변화 분석 (An Analysis of Anomalous Radon Variation Caused by M5.8 Gyeong-ju Earthquake)

  • 김진섭;김민준;김선웅;이효민
    • 자원환경지질
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    • 제51권1호
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    • pp.1-13
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    • 2018
  • 토양 내 라돈농도는 주변 환경요인들(대기온도, 대기압, 강수량, 토양온도)에 영향을 받는다. 따라서 지진에 의한 토양 내 라돈이상변화 현상을 분석하기 위해서 이들 요인에 의한 영향과 구분하여야 한다. 이번 연구에서는 환경요인에 의한 토양 내 라돈농도변화와 구분되는 2016년 9월 12일에 발생한 경주지진에 의한 라돈농도의 이상변화현상에 대하여 분석하였다. 진앙지로부터 58Km 떨어진 측정지점에서 2014년 1월 1일부터 2017년 5월 31일까지 토양 내 라돈농도와 환경요인들을 연속 측정하고, 환경요인들과의 상관성을 분석하였다. 경주 지진과 관련된 토양 내 라돈농도의 이상변화를 분석하기 위해, 계절평균농도(n)와 표준편차(${\rho}$)를 계산하고 $n{\pm}1{\rho}$$n{\pm}2{\rho}$의 범위를 벗어나는 구간을 분석하고 Earthquake effectiveness와 q-factor를 계산하였다. 토양 내 라돈농도는 여름철이 높고 겨울철이 낮은 계절변화 양상을 나타내었다. 대기온도와 토양의 온도는 높을수록 토양 내 라돈농도가 높아지는 양의 상관관계(각각 $R^2=0.9136$, $R^2=0.8496$)를 보였으며 대기압은 낮아질수록 토양 내 라돈농도가 높아지는 음의 상관관계($R^2=0.7825$)를 보였다. 경주 지진 전 후에 계절평균농도에서 $2{\rho}$범위를 벗어나는 토양 내 라돈농도의 이상변화현상은 A1(7/3~7/5), A2(7/18), A3(8/4~8/5), A4(10/17~10/20)의 4개 시점에 나타났다. 토양 내 라돈농도와 환경적 요인과의 상관관계와 Earthquake effectiveness와 q-factor를 적용하여 비교분석한 결과, A1, A2, A3 구간에서 나타난 라돈변화가 지진의 영향으로 나타난 이상변화일 것으로 판단된다. 라돈이상변화가 나타난 기간의 라돈농도와 환경요인과 상관계수(대기온도: $R^2=0.2314$, 토양온도: $R^2=0.1138$, 대기압: $R^2=0.0475$)는 다른 기간에 비교하여 매우 낮게 나타났다. 연도별 토양 내 라돈의 연평균농도를 비교한 결과, 경주지진이 발생한 2016년에 가장 높게 나타났다.

한국산 유혈목이 (Rhabodophis Tigrina) 2 아종의 분류학적 연구 (Taxonomic Study on Two Subspecies of European Grass Snake (Rhabdophis tigrina) in Korea)

  • 백남극;양서영
    • Animal Systematics, Evolution and Diversity
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    • 제2권1호
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    • pp.79-92
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    • 1986
  • 한국산 유혈목이(Rhabdophis tigrina)의 유전 및 형태적 변이를 조사한 결과 각 집단간의 유전적 근연치는 S=O.970$\pm$0.009로서 야생물군의 동종내 집단간 근연치와 동일하였으며 Rhabdophis tigrina lateralis 와 Rhabdophis tigrina tigrina 두 아종의 형태변이에 관해서는 미하판수, 복판수와 미하판수의 총수가 대륙산과 일본산 공히 북부지방에서 남부지방으로 내려올 수록 그 수가 증가하는 구배현상을 나타태고 었어 별아종으로 분류할 수 없으며 6개 형태 형질에 대한 discriminant function analysis 결과 한국산 유혈목이는 동일종임이 확인되었다. 그러므로 Rhabdophis trgrina lateralis (Berthold, 1859)은 Rhabdophis trgrina tigrina (Boie, 1826)의 동종이명으로 분류함이 타당하다고 사료된다.

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마이크로핀관 증발기내 전열 성능에 미치는 냉동기유의 영향 (Effect of refrigeration lubricants on the heat transfer performance in the microfin tube evaporator)

  • 조금남;태상진
    • 설비공학논문집
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    • 제11권1호
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    • pp.61-72
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    • 1999
  • The present study experimentally investigated the effect of refrigeration lubricant on the heat transfer performance in the straight sections and U-bend of a microfin tube evaporator by using R-22/mineral oil and R-407C/POE oil. The apparatus consisted of test section with U-bend, preheater, condenser, oil injection and sampling devices, magnetic pump, mass flow meter etc. The experimental parameters were oil concentration of 0 to 5 wt%, inlet quality of 0.1 to 0.5, mass flux of 219 and $400kg/m^2s$ and heat flux of 10 and $20kW/m^2$. The effects of parameters on the heat transfer coefficients were large in the order of inlet quality, mass flux and heat flux as oil concentration got increased. As oil concentration was increased, heat transfer coefficients were continuously decreased for R-22 and increased by 3% up to the concentration of 1% and then decreased for R-407C under the condition of large inlet quality, and small mass flux and heat flux. But, the heat transfer coefficients were increased up to the concentration of 3% and then decreased for both R-22 and R-407C refrigerants under the opposite conditions. The variation of enhancement factors for R-407C was under 50% of that for R-22 and the variation with respect to the positions in the test section was small. The pressure drops were increased for both R-22 and R-407C refrigerants as oil concentration was increased. The pressure drops for R-407C were smaller by the maximum of 18% than those for R-22.

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DNA Barcoding of Scolelepis (Scolelepis) sagittaria (Annelida, Spionidae) in Korea, with a Morphological Variability of the Species

  • Lee, Geon Hyeok;Yoon, Seong Myeong;Min, Gi-Sik
    • Animal Systematics, Evolution and Diversity
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    • 제38권3호
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    • pp.144-147
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    • 2022
  • The polychaete Scolelepis (Scolelepis) sagittaria was originally described from Japanese waters and subsequently reported from Korean waters. In this study, we determined for the first time the mitochondrial cytochrome c oxidase subunit I (COI), 16S ribosomal DNA (16S rDNA), and nuclear 18S ribosomal DNA (18S rDNA) sequences of Korean specimens of S. (S.) sagittaria. We also assessed intraspecific variation in the shape of the prostomium of this species based on an examination of 247 individuals. All materials were collected from intertidal sandy beaches of the Korea Strait. The molecular data and morphological observations reported herein will contribute to gaining a better understanding of the taxonomic relationships among members of the genus Scolelepis.

Diversity Evaluation of Xylella fastidiosa from Infected Olive Trees in Apulia (Southern Italy)

  • Mang, Stefania M.;Frisullo, Salvatore;Elshafie, Hazem S.;Camele, Ippolito
    • The Plant Pathology Journal
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    • 제32권2호
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    • pp.102-111
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    • 2016
  • Olive culture is very important in the Mediterranean Basin. A severe outbreak of Olive Quick Decline Syndrome (OQDS) caused by Xylella fastidiosa infection was first noticed in 2013 on olive trees in the southern part of Apulia region (Lecce province, southern Italy). Studies were carried out for detection and diversity evaluation of the Apulian strain of Xylella fastidiosa. The presence of the pathogen in olive samples was detected by PCR amplifying the 16S rDNA, gyrase B subunit (gyrB) and HL hypothetical protein genes and single nucleotide polymorphisms (SNPs) assessment was performed to genotype X. fastidiosa. Twelve SNPs were recorded over gyrB and six SNPs were found for HL gene. Less variations were detected on 16S rDNA gene. Only gyrB and HL provided sufficient information for dividing the Apulian X. fastidiosa olive strains into subspecies. Using HL nucleotide sequences was possible to separate X. fastidiosa into subspecies pauca and fastidiosa. Whereas, nucleotide variation present on gyrB gene allowed separation of X. fastidiosa subsp. pauca from the other subspecies multiplex and fastidiosa. The X. fastidiosa strain from Apulia region was included into the subspecies pauca based on three genes phylogenetic analyses.

Prediction of the human in vivo antiplatelet effect of S- and R-indobufen using population pharmacodynamic modeling and simulation based on in vitro platelet aggregation test

  • Noh, Yook-Hwan;Han, Sungpil;Choe, Sangmin;Jung, Jin-Ah;Jung, Jin-Ah;Hwang, Ae-Kyung;Lim, Hyeong-Seok
    • Translational and Clinical Pharmacology
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    • 제26권4호
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    • pp.160-165
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    • 2018
  • Indobufen ($Ibustrin^{(R)}$), a reversible inhibitor of platelet aggregation, exists in two enantiomeric forms in 1:1 ratio. Here, we characterized the anti-platelet effect of S- and R-indobufen using response surface modeling using $NONMEM^{(R)}$ and predicted the therapeutic doses exerting the maximal efficacy of each enantioselective S- and R-indobufen formulation. S- and R-indobufen were added individually or together to 24 plasma samples from drug-naïve healthy subjects, generating 892 samples containing randomly selected concentrations of the drugs of 0-128 mg/L. Collagen-induced platelet aggregation in platelet-rich plasma was determined using a Chrono-log Lumi-Aggregometer. Inhibitory sigmoid $I_{max}$ model adequately described the anti-platelet effect. The S-form was more potent, whereas the R-form showed less inter-individual variation. No significant interaction was observed between the two enantiomers. The anti-platelet effect of multiple treatments with 200 mg indobufen twice daily doses was predicted in the simulation study, and the effect of S- or R-indobufen alone at various doses was predicted to define optimal dosing regimen for each enantiomer. Simulation study predicted that 200 mg twice daily administration of S-indobufen alone will produce more treatment effect than S-and R-mixture formulation. S-indobufen produced treatment effect at lower concentration than R-indobufen. However, inter-individual variation of the pharmacodynamic response was smaller in R-indobufen. The present study suggests the optimal doses of R-and S-enantioselective indobufen formulations in terms of treatment efficacy for patients with thromboembolic problems. The proposed methodology in this study can be applied to the develop novel enantio-selective drugs more efficiently.