• 제목/요약/키워드: $K_s$

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Solubilization of Benzenesulfonate anion and Its Derivatives by the Micellar System of TTAB (TTAB 용액에서 Benzenesulfonate 음이온과 유도체들의 가용화에 대한 연구)

  • Lee, Byung-Hwan
    • Journal of the Korean Chemical Society
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    • v.45 no.1
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    • pp.7-13
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    • 2001
  • The interaction of benzenesulfonate anion and its derivatives ($C_6H_5SO_3^-, p-$CH_3C_6H_4SO_3^-, and $p-C_2H_5C_6H_4SO_3^-$) with the micellar system of cationic surfactant TTAB(tetradecyltrimethylammonium bromide) was studied by UV/Vis spectrophotometric method. The solubilization constants($K_s$) of benzenesulfonate anions into the micellar phase of this surfactant have been measured with the change of temperature. The effects of additives(n-pentanol and NaBr) on the solubilization of benzenesulfonate anions by this surfactant system have been also measured. There was a great decrease on the values of $K_s$ and CMC simultaneously with these additives so that the measured values of ln$K_s$ were linear relationships with the values of lnCMC. For the thermodynamic study, various thermodynamic parameters(${\Delta}G^0_s$, ${\Delta}H^0_s$ and ${\Delta}S^0_s$) have been calculated and analyzed from the dependence of Ks values on temperature.

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The Fault Location Estimation Algorithm in Transmission Line Using a Recursive Least Square Error Method (순환형 최소자승법을 이용한 송전선로의 고장점 추정 알고리즘)

  • Yoon, C.D.;Lee, J.J.;Jung, H.S.;Shin, M.C.;Choi, S.Y.
    • Proceedings of the KIEE Conference
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    • 2002.07a
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    • pp.203-205
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    • 2002
  • This paper presents the fault location estimation algorithm in transmission line using a recursive least square error method (RLSE). To minimize the computational burden of the digital relay a RLSE approach is used. Computer simulation results of the RLSE algorithm seem promising, indicating that it should be considered for further testing and evaluation.

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A Study on Nursing and Non-Nursing College Students' Knowledge and Attitudes of HIV/AIDS and Hepatitis B (간호대학생과 비 간호계열 대학생의 HIV/AIDS와 B형 간염에 대한 지식 및 태도)

  • Lee, Hyeong Suk;Park, Haena;Kim, Keun Hee;Kim, Mi Ri;Kim, Mingee;Kim, Bit Na;Kim, Eun Kyung;Kim, Eun Yong;Kim, Jin Hee;Seong, Hye Jin;Song, Misun
    • Journal of Korean Public Health Nursing
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    • v.29 no.3
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    • pp.474-487
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    • 2015
  • Purpose: This study was conducted to describe the knowledge and attitudes of nursing and non-nursing college students toward HIV/AIDS and Hepatitis B. Methods: A descriptive design was used for this study. The subjects were 123 nursing college students and 128 non-nursing college students. Self-administered questionnaires were used for data collection. Descriptive statistics, ${\chi}^2$-test, t-test, ANOVA, and Pearson correlation coefficient were used for data analysis. Results: Nursing students showed a greater understanding and more favorable attitudes towards HIV/AIDS and hepatitis B than non-nursing college students. Most non-nursing college students learned about HIV/AIDS and hepatitis B from Mass Media. In contrast, many nursing college students learned about HIV/AIDS and hepatitis B from technical books and lecture. Students who learned from technical books and lecture showed a higher score for knowledge and more favorable attitudes regarding HIV/AIDS and hepatitis B. Conclusion: The findings of this study demonstrated that educational opportunities in school are crucial to enhancing knowledge and attitudes toward HIV/AIDS and Hepatitis B. A structured education program using strategies to improve attitudes is necessary for college students.

Hepatoprotective activity of methanol extracts of Berberis tinctoria

  • P, Vijayan;HC, Prashanth;Vijayaraj, Preethi;H, Raghu Chandrashekhar;Godavarthi, Ashok;SA, Dhanaraj
    • Advances in Traditional Medicine
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    • v.6 no.1
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    • pp.45-52
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    • 2006
  • The methanol extracts of the roots, root bark and stem of Berberis tinctoria, were investigated for their hepatoprotective activity against carbon tetrachloride $(CCl_4)$ induced toxicity in freshly isolated rat hepatocytes, HEp-G2 cells and animal models. The methanol extracts were able to significantly normalise the levels of aspartate amino transferase, alanine aminotransferase, alkaline phosphatase, triglycerides, total proteins, albumin, total bilirubin and direct bilirubin, which were altered due to $CCl_4$ intoxication in freshly isolated rat hepatocytes and also in animal models. The anti-hepatotoxic effect of the methanol extracts in vitro were observed at $600\;-\;1,000\;{\mu}g/ml$ concentrations. A dose dependent increase in the percentage viability was observed when $CCl_4$ exposed HEp-G2 cells were treated with different concentrations of the methanol extracts. The highest percentage viability of HEp-G2 was observed at a concentration of $1,000\;{\mu}g/ml$. The results from the present investigations also indicate good correlation between the in vivo and in vitro studies.

Characteristics of Flow Sensor Using PTC Thermistor (PTC 써어미스터를 이용한 유속센서의 특성)

  • Kwon, Hyuk-Joo;Lee, Yang-Hyun
    • Journal of Sensor Science and Technology
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    • v.3 no.3
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    • pp.3-8
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    • 1994
  • Flow sensor was fabricated with PTC thermistor usually operating as thermostats. The PTC thermistor was manufactured with $(Ba_{0.7}Sr_{0.3})TiO_{3}$ powder and its resistivity as a function of flow velocity was investigated. The resistivity changed from 4.45 $k{\Omega}{\cdot}cm$ to 3.95 $k{\Omega}{\cdot}cm$ as flow velocity varied 0 cm/s to 5 cm/s The sensitivities of the PTC thermistor were -204 (${\Omega}{\cdot}cm$)/(cm/s) and -24 (${\Omega}{\cdot}cm$)/(cm/s) at the flow velocity of 1 cm/s and 5 cm/s, respectively.

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