• 제목/요약/키워드: P-N Curve

검색결과 455건 처리시간 0.03초

철근 콘크리트 충전 PHC말뚝의 휨 설계 및 성능 평가 (Flexural Design and Experiments on Reinforced Concrete Filled PHC Pile)

  • 김정회;정해광;박영식;민창식
    • 콘크리트학회논문집
    • /
    • 제29권4호
    • /
    • pp.353-360
    • /
    • 2017
  • PHC말뚝을 보강한 CFP말뚝의 P-M 상관도를 통한 휨 모멘트 예측과 휨 실험 결과를 통해 P-M 계산법의 타당성과 CFP말뚝의 휨 성능을 평가한 실험 연구이다. 시험체는 PHC말뚝과 링형 합성 전단연결재 그리고 속채움 콘크리트를 기본으로 한 CFP말뚝과 1차 보강(말뚝 보강철근 H13-8ea), 2차 보강(내부 보강철근 H19-8ea)으로 제작된 시험체의 휨 실험 결과 CFP-N-N 시험체 대비 최고 하중이 46.4%, 103.9% 증대되었으며, 보강 철근량에 따른 연성능력 증대가 이루어졌다. 또한 CFP말뚝 설계법의 극한한계상태 예측값과 실험 결과값을 비교해 볼 때, 각 보강 단계별 1.23, 1.40배의 안전율을 확보하여 본 연구에서 제시한 설계법이 합리적인 것으로 판단된다.

클로라민 소독에 의한 THMs 생성에 관한 연구 (A Study the THMs Formation by Chloramination Disinfection)

  • 김평청;우달식;남상호
    • 환경위생공학
    • /
    • 제14권1호
    • /
    • pp.11-16
    • /
    • 1999
  • This study was performed to investigate THMs formation by chloramination as a secondary disinfection in drinking water distribution system. As the $Cl_2/NH_3-N$ ratio increased from 1:1 to 4:1, the THMs concentration had actually no change in the breakpoint curve of pH 6, 7. At pH 8, THMs level was not augmented at between 1:1 and 5:1. In the $Cl_2/NH_3-N$ ratio of more than 5:1 and 6:1 respectively, THMs level was raised. Only the chloroform of THMs was insignificantly detected by both preformed chloramine and preammoniation applications, which was probably attributed to the stoichiometrically unstable equilibrium in the preparation of chloramine, whereas $CHCl_3$, $CHCl_2Br$ and $CHClBr_2$ of THMs were found in the application of free chlorine. However it turned out that the THMs levels by chloramine was incomparably inferior to that of free chlorine.

  • PDF

제어 반전 소자의 제조 및 그 특성 (Fabrication and Characteristics of the Controlled Inversion Devices)

  • 김진섭;이우일
    • 대한전자공학회논문지
    • /
    • 제20권1호
    • /
    • pp.45-49
    • /
    • 1983
  • Metal/insulator/n epi-layer/p+구조의 CID(controlled inversion device)를 제조하였다. I-V 특성 곡선에서 ON상태와 OFF상태사이에 부성저항(negative resistance)영역이 나타났다. CID를 제조하기 위해서 행한 산화층 형성 과정에서 600℃에서 5분간 산화시킨 소자의 스위칭 및 홀딩 전압은 각각 5.0V와 2.5V였다. 그리고 입사된 광에 의해서 스위칭 전압은 감소하였으나 홀딩 전압은 변하지 않았다.

  • PDF

구상흑연주철의 피로수명분포에 대한 통계적 해석 (A Statistical Analysis on Fatigue Life Distribution in Spheroidal Graphite Cast Iron)

  • 장성수;김상태
    • 대한기계학회논문집A
    • /
    • 제24권9호
    • /
    • pp.2353-2360
    • /
    • 2000
  • Statistical fatigue properties of metallic materials are increasingly required for reliability design purpose. In this study, static and fatigue tests were conducted and the normal, log-normal, two -parameter Weibull distributions at the 5% significance level are compared using the Kolmogorov-Smirnov goodness-of-fit test. Parameter estimation were compared with experimental results using the maximum likelihood method and least square method. It is found that two-parameter Weibull distribution and maximum likelihood method provide a good fit for static and fatigue life data. Therefore, it is applicable to the static and fatigue life analysis of the spheroidal graphite cast iron. The P-S-N curves were evaluated using log-normal distribution, which showed fatigue life behavior very well.

피로시험 데이터의 산포를 고려한 스프링의 신뢰성 최적설계 (Reliability based optimization of spring fatigue design problems accounting for scatter of fatigue test data)

  • 안다운;원준호;최주호
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2008년도 추계학술대회A
    • /
    • pp.1314-1319
    • /
    • 2008
  • Fatigue reliability problems are nowadays actively considered in the design of mechanical components. Recently, Dimension Reduction Method using Kriging approximation (KDRM) was proposed by the authors to efficiently calculate statistical moments of the response function. This method, which is more tractable for its sensitivity-free nature and providing the response PDF in a few number of analyses, is adopted in this study for the reliability analysis. Before applying this method to the practical fatigue problems, accuracies are studied in terms of parameters of the KDRM through a number of numerical examples, from which best set of parameters are suggested. In the fatigue reliability problems, good number of experimental data are necessary to get the statistical distribution of the S-N parameters. The information, however, are not always available due to the limited expense and time. In this case, a family of curves with prediction interval, called P-S-N curve, is constructed from regression analysis. Using the KDRM, once a set of responses are available at the sample points at the mean, all the reliability analyses for each P-S-N curve can be efficiently studied without additional response evaluations. The method is applied to a spring design problem as an illustration of practical applications, in which reliability-based design optimization (RBDO) is conducted by employing stochastic response surface method which includes probabilistic constraints in itself. Resulting information is of great practical value and will be very helpful for making trade-off decision during the fatigue design.

  • PDF

화학발광법에 의한 비타민 P1의 정량 (Determination of vitamin P1 by chemiluminescence method)

  • 진승오;이상학
    • 분석과학
    • /
    • 제21권1호
    • /
    • pp.20-24
    • /
    • 2008
  • 본 연구에서는 lucigenin과 $H_2O_2$에 의한 화학발광을 이용하여 vitamin $P_1$을 정량하는 방법에 대하여 연구하였다. 분석의 최적 조건을 구하기 위해서 화학발광에 영향을 미치는 $H_2O_2$의 농도, pH 그리고 lucigenin의 농도를 조사하였다. 이러한 분석 최적조건의 검정곡선에서 직선성이 성립하는 범위는 $7.5{\times}10^{-6}$에서 $5.0{\times}10^{-4}mol/L$이었고, 검정곡선에서 직선성이 성립하는 농도구간에서 구한 검출한계는 $5.7{\times}10^{-7}mol/L$이었다. 최적 vitamin $P_1$의 농도인 $7.5{\times}10^{-5}mol/L$에서의 상대표준편차는 0.75%(n=10), 상관계수(S/N=3)는 0.9984이었다.

MOVE.2 확장기법 적용을 통한 장기 부하지속곡선 구축 및 유황조건별 수체손상평가 (Construction of Long-term Load Duration Curve Using MOVE.2 Extension Method and Assessment of Impaired Waterbody by Flow Conditions)

  • 김경훈;권헌각;임태효;이규동;신동석;나승민
    • 한국물환경학회지
    • /
    • 제33권1호
    • /
    • pp.51-62
    • /
    • 2017
  • The purpose of this study is to evaluate on the applicability of Load Duration Curve (LDC) method using Maintenance of Variance Extension types 2 method and sampling data for efficient total maximum daily loads at the Nakbon-A unit watershed in Korea. The LDC method allows for characterizing water quality data such as BOD, TOC, T-N and T-P in this study at different flow regimes(or quarters). BOD usually exceeded the standard value (exceedance probability 50%) at low flow zone. On the other hand, TOC, T-N, T-P usually exceeded the standard value at dry and low flow zone. Seasonally all water quality variables usually exceeded the standard value at Q1(Jan-Mar) and Q2(Apr-Jun) zones. Improvement of effluent control from wastewater treatment plants are effective to improve BOD and T-P.

Mequitazine의 Muscarine수용체에 대한 작용 (Effect of Mequitazine on the Muscarinic Receptors)

  • 이신웅;장태수
    • Biomolecules & Therapeutics
    • /
    • 제3권3호
    • /
    • pp.192-198
    • /
    • 1995
  • The affinity of mequitazine, a non-sedating antihistamine, for muscarinic receptors was evaluated in the guinea-pig ventricle and ileum by in vitro binding techniques and functional studies. In binding studies, [$^3$H]quinuclidinyl benzilate (QNB) identified a single class of muscarinic receptors with similar apparent $K_{D}$ value of about 100 pM in two tissues. Mequitazine inhibited [$^3$H]QNB binding to muscarinic receptors competitively. Analysis of the mequitazine inhibition curve of [$^3$H]QNB binding to ventricular microsome and ileal homogenate indicated the presence of a single homogeneous binding site with Ki value of 25 nM and 18 nM, respectively. In functional studies, mequitazine caused parallel rightward shifts of concentration-response curves for carbachol and histamine in the isolated guinea-pig ileum. The slope values obtained from Schild plot analysis for the antagonistic action of mequitazine on muscarinic and histamine $H_1$-receptors were not significantly different from unity. The p $A_2$values of mequitazine for muscarinic and histamine $H_1$-receptors were about 7.6 ( $K_{M}$= 25.1 nM) and 8.88 ( $K_{H}$= 1.32 nM), respectively. These results indicate that the muscarinic receptor blocking action of mequitazine is 15 times less potent than the $H_1$receptor blocking action, but high concentration of this drug may cause the peripheral muscarinic receptor blocking effect.t.t.t.

  • PDF

조생온주 밀감의 품종에 따른 Flavonoids 함량 분석에 관한 연구 (HPLC Analysis of Some Flavonoids in Citrus Fruits)

  • 이창환;강영주
    • 한국식품저장유통학회지
    • /
    • 제4권2호
    • /
    • pp.181-187
    • /
    • 1997
  • New HPLC method was developed for determination of some flavonoids such as naringin, hesperidin, neohesperidin, rutin, quercitrin, naringenin, hesperetin and apigenin and their contents in citrus juice and citrus peel from citrus varieties Brown in Cheju. Detection was at 280nm and reverse phase ${\mu}$-Bondapak C-18 column was used. Water/methanol/acetic acid as the mobile phase was better than water/acetonitrile/acetic acid. Flavonoids were more stable in 20% n,n-dimethylformamide in methanol(20% DMF) than methanol and pH 12 adjusted by 1N-sodium hydroxide solution. Standard flavonoid solutions were injected three times consecutively and the reproduciability was 0.236 to 3.550%, Correlation coefficient of the calibration curve was 0.9946 to 0.9999. The exiraction efficiency of hesperidin from citrus peel was evaluated with different extraction method such as reflux, ultra-sonicating method, using three solvents (aqueous solutions with pH12 adjusted by 1N-sodium hydroxide, methanol and 20% DMF), respectively. The reflux for 4 hour in 20% DMF was the most efficient of the tested methods and solvents, and recovery percentage were 78.0∼130.0%. Flavonoids were determined in citrus juice. Naringin was 68.2mg/100$m\ell$ in Natsudaidai, Hesperidin were 85.6mg/100$m\ell$ in Sankyool and Neohesperidin was 25.3mg/100$m\ell$ in Dangyooja. Flavonoids were determined in citrus peel. Naringin was 110mg/g in Dangyooja, Hesperidin was 242mg/g in Hungjin and Neohesperidin was 87.9mg/g in Dangyooja.

  • PDF

SERKOWSKI'S EMPIRICAL RELATION FOR INTERSTELLAR LINEAR POLARIZATION VIEWED FROM DAVIS-GREENSTEIN ALIGNMENT MECHANISM

  • Hong, Seung-Soo;Lee, Hyung-Mok
    • 천문학회지
    • /
    • 제11권1호
    • /
    • pp.31-36
    • /
    • 1978
  • Although Serkowski used a single value K=1.15 in representing all the observed interstellar linear polarization curves by his empirical relation $p({\lambda})/P_{max}$=exp (-K $1n^2({\lambda}_{max}/{\lambda})$), where $p_{max}$ is the maximum polarization at wavelength ${\lambda}_{max}$, we have noticed a meaningful variation in K from observations of 72 stars. By comparing K's with $P_{max}/E_{B-V}\;and\;with\;{\lambda}_{max}$, we have examined how the shape of the polarization curve is related with the degree of grain alignment on one hand, and with grain sizes on the other. We have shown that correlations between K, $P_{max}/E_{B-V}\;and\;with\;{\lambda}_{max}$, are consistent with the idea of Davis-Greenstein mechanism for grain alignment.

  • PDF