• Title/Summary/Keyword: equivalent concentration

Search Result 583, Processing Time 0.024 seconds

Analyses of Spectral IP Responses over 20-Degree Dipping Structure (20도 경사구조에 대한 스펙트럴 IP응답의 해석)

  • Kim, Hee Joon
    • Economic and Environmental Geology
    • /
    • v.19 no.3
    • /
    • pp.219-224
    • /
    • 1986
  • Spectral induced polarization (IP) responses for 20-degree dipping body are obtained by both numerical and scale models. The IP responses for the dipping body vary not only with current frequencies but also with resistivity ratios between the body and the surrounding medium. If the ion concentration related to polarizable reaction is constant, the resistivity of polarizable body depends only on the current frequency. This implies that the IP responses to the resistivity ratio are qualitatively equivalent to those to the current frequency. The numerical results with wide-range resistivity ratios, therefore, can be used as standard curves for the interpretation of spectral IP data.

  • PDF

Rapid estimation of salinity in seawater intrusion zones and correlation analysis between resistivity and salinity (해수침투 지역의 염분농도 분포 파악 및 전기비저항의 상관성분석 사례)

  • Jung, Lae-Chul;Kim, Jung-Ho;Kim, Ki-Seog;Kim, Jong-Hoon;Ahn, Hee-Yoon
    • 한국지구물리탐사학회:학술대회논문집
    • /
    • 2007.06a
    • /
    • pp.307-312
    • /
    • 2007
  • Seawater intrusion in estuarine regions is an important issue in protecting groundwater against salinity increase as well as in protecting construction materials against corrosion. For example, drain water ejected during accelerated consolidation for the improvement of soft ground can cause damages to farm land because the drain water from seawater intrusion zones contains salinity. In this study, we have employed correlation analysis between resistivity value and salinity of in situ pore water. The correlation analysis indicates that resistivity and salinity are in exponential relationship with good correlation. Therefore we suggest that rapid estimation of spatial distribution of NaCl is possible using resistivity data.

  • PDF

Magnetic and Ordering Behavior of Nb-doped FePt Alloy Films

  • Kim, Min-Kyu;Lee, Seong-Rae
    • Journal of Magnetics
    • /
    • v.10 no.1
    • /
    • pp.28-32
    • /
    • 2005
  • The magnetic properties and ordering behavior of Nb-doped FePt alloy films prepared by dc-magnetron sputtering were investigated. It was found that Nb addition retarded the ordering reaction from the disordered face-centered-cubic (fcc) Al phase to the ordered face-centered-tetragonal (fct) L10 phase. The tetragonality (c/a ratio) of the ordered fct L10 phase increased with the Nb concentration. Nb addition hampered c-axis contraction during ordering, probably because the larger Nb atoms occupy Pt sites. Consequently, the coercivity and magnetocrystalline anisotropic energy of Nb-doped FePt alloy films are lower than those of un-doped FePt film under equivalent annealing conditions.

A Study on the Effectiveness of Smart Education Based on Learning Ability

  • Song, JeongBeom
    • Journal of the Korea Society of Computer and Information
    • /
    • v.21 no.9
    • /
    • pp.165-176
    • /
    • 2016
  • This study developed the learning ability-based smart education program. The effectiveness of the developed materials was investigated using the quantitative-qualitative mixed method, and the process and results of the investigation are as follows. The quantitative investigation was conducted using the non-equivalent pretest-posttest design, in which the smart education method was applied to the experimental group, while the conventional education method was applied to the control group to analyze students' creative problem-solving potential, task concentration, and the variables required for the learning activity. The results showed significantly higher performance in the experimental group over the control group. Regarding data collection in the qualitative investigation, an analysis of the class from the instructor and class consultation logs from the class analyst were collected; the comments on the experience of each class period were collected from students. The results of the analysis of the data suggest that the perception of smart education improved for the instructor, class analyst, and learners as the course progressed.

The Effects of Garlic (Allium sativum L.) Extract on Growth, Lipid and Aflatoxin Production by Aspergillus parasiticus R-716 (Aspergillus parasiticus R-716의 生育, 脂質 및 Aflatoxin 生産에 미치는 마늘(Allium sativum L.)엑기스의 영향)

  • Woo, Young Sook;Chung, Duck Hwa
    • Journal of Environmental Health Sciences
    • /
    • v.10 no.2
    • /
    • pp.89-97
    • /
    • 1984
  • The possible effects of garlic (Aliium sativurn L.) extract on growth and aflatoxin production by Aspergillus parasiticus R- 716 were investigated. Various solvent extracts of garlic strongly inhibited growth and sporulation by Aspergillus parasiticus R-716, and effective solvents used for extraction of garlic were chloroform, benzene, and water-chloroform. The growth and aflatoxin production decreased with the increase in extract concentration, and extract equivalent 1.5g of raw garlic weight in 25ml SLS medium completely inhibited, and at a level of 1.25g garlic, total aflatoxin was reduced 64% (472 ${\mu}g$/25ml) of that produced in the control (1, 352 ${\mu}g$/25 ml). During cultivation inhibitory rate of growth was reduced from 89.1% to 40% and aflatoxin $B_2$, $G_1$ production increased with the laps of time. Especially garlic extract appeared to have a stimulatory effect on lipid accumulation on the contrary aflatoxin production.

  • PDF

A Surge Voltage Distribution Analysis of 2MVA Cast Resin Transformer Winding with FEM Simulation (FEM 시뮬레이션을 이용한 2MVA 몰드변압기 권선간 써지전압 분배 해석 기법 연구)

  • Jang, Hyeong-Taek;Shin, Pan-Seok
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.25 no.5
    • /
    • pp.15-21
    • /
    • 2011
  • This paper presents an analyzing method of the capacitance of the power transformer for initial voltage distribution and insulation design. When a high incoming surge voltage is accidently occurred in windings of transformer, it does not distribute equally in the windings. This phenomenon makes electric field concentration and the insulating material could be break. Initial voltage distribute mostly depends on capacitances between winding to winding or winding to core in the transformer. If the C network can be structuralized into the equivalent circuit model and be calculated each capacitance element value by circuit analysis and FEM(Finite Element Method) simulation program, the transformer designer could know the place where the structure is to be modified or the insulation to be reinforced. This method quickly provides the data of the voltage distribution in each winding to the designer.

Characterization of In-Situ Film Thickness and Chamber Condition of Low-K PECVD Process with Impedance Analysis

  • Kim, Dae Kyoung;Jang, Hae-Gyu;Kim, Yong-Tae;Kim, Hoon-Bae;Chae, Hee-Yeop
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2010.02a
    • /
    • pp.461-461
    • /
    • 2010
  • For a low dielectric constant inter-metal dielectric application, the low-k SiCOH film with a dielectric constant of 2.8-3.2 has been deposited by plasma-enhanced chemical vapor deposition with decamethylcyclopentasiloxane, cyclohexane, and helium which is carrier gas. In this work, we investigated chemical deposition rate, dielectric constant, characterization of plasma polymer films according to temperature(25C-200C) of substrate and change of component concentration. We measured impedance by using V-I prove during process. From experimental result, deposition rate decrease with increasing temperature. Through real time impedance analysis of chamber, we find corelation between film thickness and impedance by assuming equivalent circuit.

  • PDF

Optimization of Extraction Conditions for Dried Jujube by Response Surface Methodology (반응표면분석에 의한 건대추의 추출조건 최적화)

  • Woo, Koan-Sik;Lee, Sang-Hoon;Noh, Jin-Woo;Hwang, In-Guk;Lee, Youn-Ri;Park, Hee-Jeong;Lee, Jun-Soo;Kang, Tae-Su;Jeong, Heon-Sang
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.38 no.2
    • /
    • pp.244-251
    • /
    • 2009
  • Extraction characteristics of dried jujube and functional properties of corresponding extract were monitored by response surface methodology. Maximum extraction yield of 53.69% was obtained at extraction temperature of $50.35^{\circ}C$, extraction time of 16.69 hr, and ethanol concentration of 72.88%. At extraction temperature, extraction time, and ethanol concentration of $45.80^{\circ}C$, 15.47 hr, and 73.12%, respectively, maximum cyclic adenosine monophosphate content was 8.20 mg/100 g. Maximum total polyphenol content was 18.85 mg/g at extraction temperature, extraction time, and ethanol concentration of $64.91^{\circ}C$, 20.84 hr, and 66.91%, respectively. Maximum total flavonoid content was 0.48 mg/g at extraction temperature, extraction time, and ethanol concentration of $57.36^{\circ}C$, 15.14 hr, and 71.08%, respectively. $IC_{50}$ value of electron donating ability showed maximum level of 32.34 mg/mL at extraction temperature of $48.46^{\circ}C$, extraction time of 19.25 hr, and ethanol concentration of 65.36%. Maximum ascorbic acid equivalent antioxidant capacity was 3.58 mg ascorbic acid equivalent per gram sample at extraction temperature, extraction time, and ethanol concentration of $56.09^{\circ}C$, 21.86 hr, and 65.36%, respectively.

Estimated EC by the Total Amount of Equivalent Ion and Ion Balance Model (등가 이온 총량에 따른 EC 추정과 이온 균형 모형)

  • Soh, Jae-Woo;Lee, Yong-Beom
    • Horticultural Science & Technology
    • /
    • v.30 no.6
    • /
    • pp.694-699
    • /
    • 2012
  • To examine the EC model in a culture medium, basic culture medium of Rush (2005) and EC model of Robinson and Strokes (1959) were applied analyzing the equivalence ion total amount, the EC variable of cation and anion. Following the experiential translation by Steiner (1980), 130 optimized domestic and foreign culture media for crop growth were utilized, and estimated EC model was also demonstrated. Results from basic culture medium of Rush (2005) suggests an estimated EC by equivalence ion total amount and high reliable regressive model with 0.96 y = 1.33x - 0.23 of 0.96 as value $R^2$. It was found out that the change in concentration of positive ion and anion did not differ significantly with the increase and decrease of EC, however, there occurred a slight variable range. The change brings about a bigger anion influence than the previously reported positive ion, seemingly like those based on nitride ion and sulfur ion. The above EC estimated models confirmed that with optimized 130 domestic and foreign culture media for crop growth, the value derived will be as follows: $R^2$ = 0.98 with y = 1.23x - 0.02. In addition, the contour analysis of positive ion and anion for EC, with popularly known concentration range of EC $1.5-2.5dS{\cdot}m^{-1}$ reveals an equivalent of more than $11meq{\cdot}L^{-1}$ for positive ion and $15meq{\cdot}L^{-1}$ for anion. On the other hand, the left bottom, low concentration $1.5dS{\cdot}m^{-1}$ and the right above, high concentration $2.5dS{\cdot}m^{-1}$, for both positive ion and anion existed differently in a proper culture medium concentration. This study adapted variables of both positive ion and anion of EC simultaneously, unlike in the previous culture medium by ion ratio in mutual ratio of Steiner (1980), and offers an EC model that can estimate levels or positive ion and anion in proper concentration, EC $1.5-2.5dS{\cdot}m^{-1}$, with distributed features of ions.

The Analysis of Perchlorate in Nakdong River and Tap Water (낙동강 수계 및 수돗물에서의 Perchlorate($ClO_4^-$) 분석)

  • Kim, Hwa-Bin;Oh, Jeong-Eun;Lee, Sung-Yun;Cho, Jae-Weon;Snyder, Shane
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.28 no.7
    • /
    • pp.776-781
    • /
    • 2006
  • Perchlorate ion($ClO_4^-$), which is present in the solid propellant for rocket, herbicide and some fertilizers. Perchlorate inhibits iodide uptake by the human thyroid gland. Impairment of thyroid function in expectant mothers may impact the fetus and result in effects including cerebral palsy, give rise to thyroid gland cancer. The US EPA(Environmental Protection Agency) adopted a reference dose(RfD) for perchlorate 0.0007 mg/kg-day, and this guidance lead to a Drinking Water Equivalent Level(DWEL) of 24.5 ${\mu}g/L$. The studies about perchlorate are actively performed in foreign countries, especially in USA but there is no study which surveyed the perchlorate contamination in Korea. Therefore, this study was done to investigate perchlorate contamination in Nak-dong river and tap water. The perchlorate was detected in Nakdong river and ranged from ND to 278.4 ${\mu}g/L$. The highest concentration was observed in Kumichon. The perchlorate concentration was decreased with the down stream of Nakdong river. The perchlorate concentration in tap water was varied with the cities and the concentration levels were $ND{\sim}34.1$ ppb. The highest perchlorate concentration was observed in DalsuGoo in Daegu and the similar concentration($9{\sim}11$ ${\mu}g/L$) was detected in most of the districts in Busan. The result of this study suggests that there is a perchlorate source near the Nakdong river and the urgent policy is needed to control perchlorate for the cities which are supplied from Nakdong river as for their tap water.