• 한국농공학회지
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• 제31권1호
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• pp.96-105
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• 1989

This laboratory study was performed to produce basic data for the estimation of water requirements for desalinization, through analyzing changes of the electrical conductivity and the exchangeable sodium percentage during the desalinization of reclaimed tidelands. Desalinization experiments were carried out by two water management practices, namely, the leaching method by subsurface drainage and the rinsing method by surface drainage, using samples of silt loam soil and silty clay loam soil collected in reclaimed tidelands. The results obtained from this study were summarized as follows : 1. The sample soils used in this study were saline-sodic soils with the high electrical conductivity and the high exchangeable sodium percentage. 2. Changes of the electrical conductivity and the exchangeable sodium percentage with water requirements for desalinization showed a similar tendency in the desalinization experiment by the same water management practice. 3. The regression equation between the relative electrical conductivity(EC/EC) and water requirements for desalinization(Dw/Ds) could be described by Dw/Ds=O. 29x(EC/EC.) -0.982 (Leaching method), Dw/Ds=3. 678X0. 030(EC/EC ) (Rinsing method). 4. The regression equation between the relative exchangeable sodium percentage (ESP/ESP ) and water requirements for desalinization (Dw/Ds) could be expressed in Dw/Ds = 0.039 x (ESP/ESP. ) - 1. 134 (Leaching method), Dw/Ds=7. 197X0. 024(ESP/ESP ) (Rinsing method). 5. It was estimated that water requirements for the adequate desalinization would be Dw/Ds=0.3 (Leaching method) and Dw/Ds=3.0 (Rinsing method)

• 대한수의학회지
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• 제24권1호
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• pp.91-98
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• 1984

A total of 466 foremilk from dairy farms in Chonnam district was examined for the subclinical mastitis over a period of one year, using a method of the electrical conductivities(EC); absolute conductivity(AC) and differential conductivity(DC) and quarter difference value(QD), in relation to the California mastitis test(CMT) and the direct somatic cell count(DSCC). The compatibility and efficiency rating between the EC values and the other screening tests was conducted. Obtained results are summarized as follows. 1. A linear relationship was found between the EC values and the CMT scores and direct somatic cell counts and it was found that electrical conductivity measurements were comparable with other screening tests for diagnosing animals with mastitis. 2. Compatibilities between the EC and CMT were 70.4% in AC, 74.6% in DC and 70.7% in QD, and that of the EC and DSCC were 53.0% in AC, 63.1% in DC and 53.2% in QD. On the other hand, relative efficiency ratings of Postle's equation between EC and CMT were 37.3% in AC, 26.5% in DC and 13.6% in QD, and that of the EC and DSCC were 33.1% in AC, 20.2% in DC and 11.9% in QD. 3. In the foremilk samples collected from damaged quarters determined by EC, the false positive rate wart higher than the false negative rate, and consequently tests of EC produced lower compatibility or efficiency rating scores. These tendencies suggested that any factors other than the mastitic condition influencing the EC values might be existed.

• 한국토양비료학회지
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• 제28권3호
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• pp.241-248
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• 1995

연작(連作)으로 재배되고 있는 꽈리풋고추 비닐하우스 재배지토양의 화학적 성질을 진단하고 이와 작물생육과의 관계를 밝힐 목적에서 충남 당진군내 36개 농가포장을 조사 분석한 결과를 요약하면 다음과 같다. 1. 토양화학성분중 가장 높은 빈도(頻度)를 보인 범위 및 비율은 pH 6.1~6.5(36%), OM 1.6~2.0%(31%), 유효인산 601~800mg/kg(39%), CEC 12.1~14.0 c mol/kg(39%), clay 16.1~18.0% (50%), 전기 전도도 EC 2.0 dS/m 이하가 44%로 많았다. 2. 풋고추 수량은 pH, CEC, 유기물 함량, 점토 함량과는 고도의 정산관(正相關)이 있었고 EC와는 고도의 부(負)의 상관(相關)을 보였다. 3. 전기전도도 EC값은 CEC와 파장 높은 부상관($r=-0.81^{**}$)이 있었고, 점토함량 또는 유기물 함량과도 고도의 부상관이 있었다. 4. 토양화학성분과 EC와의 상관관계에서 EC를 2.0dS/m 이하로 낮추는데에는 점토 18%, 유기물 2.3%이상이 되어야 한다는 것을 나타내었다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.40-43
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• 2000

Groundwater qualities in Nakdong river region were investigated during 1999 and 2000. Groundwater samples were collected twice from about 150 sites over the region. The EC and TDS obtained in first survey (October, 1999) show rather high values than those in second survey(April, 2000) and this seems to be caused by groundwater temperature. There is obvious positive correlation between EC and TDS. For the study area, the following equation can be written : TDS(mg/l) = <0.64~0.70> x EC($mutextrm{s}$/cm). As the concentration of major ions increases in natural condition, there is a tendency that the ratio of TDS and EC has consistent value. This observation suggests that TDS measurement can be replaced by EC measurement in the some ranges.

• 한국토양비료학회지
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• 제36권1호
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• pp.1-7
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• 2003

Time Domain Reflectometry(TDR)은 토양의 순분함량과 전기전도도를 측정할 수 있는 비파괴적인 방법이다. 초기 전자파에 대한 TDR 반향파의 감쇄정도를 이용하여 토양의 총전기전도도($EC_a$)를 직접 계산할 수 있는 다양한 식들이 제안된 바 있다. 또한, $EC_a$로부터 보다 실질적인 의미가 있는 토양 용액의 전기전도도($EC_w$)를 계산하기 위해서는 일정 토양 수분 함량에서 $EC_a$와 $EC_w$가 갖는 직선관계식[$EC_a=EC_w{\theta}(a{\theta}+b)+EC_s$]이 이용된다. 따라서 본 연구에서는 TDR 신호를 이용하여 $EC_a$를 계산할 수 있는 다양한 식을 비교하여 가장 적합한 식을 제안하고, 농경지 토양(강서통, A, B1, B2 층위)을 대상으로 $EC_a$로부터 $EC_w를 계산할 때 필요한 실험상수(a, b, $EC_s$)를 구하고자 하였다. $EC_a$는 KCl 농도가 증가함에 따라 직선적으로 증가하였고, 특히 Yanuka 등이 제안한 식으로 계산한 $EC_a$가 용질 농도에 가장 민감하게 반응하였다. 직선회귀식을 이용하여 $EC_a$와 $EC_w$의 상관관계식의 실험 상수 (a, b, $EC_s$)를 구한 결과, 각각 -0.249, 1.358, 0.054(A층), -2.518, 2.708, 0.097(B1층), 2.490, -0.250, 0.103 (B2층)으로 조사되었다. 따라서 이상의 연구 결과는 TDR 신호를 이용해서 염농도가 낮은 일반 농경지 토양의 $EC_a$를 계산할 때 Yanuka 등이 제안한 식을 적용하는 것이 바람직하며, $EC_w$를 계산할 때 이용되는 $EC_w$-$EC_a$ 상관관계식의 상수는 간단한 실험실내 보정 시험을 통해 구할 수 있음을 보여준다.

• 한국토양비료학회지
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• 제29권4호
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• pp.396-402
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• 1996

식물생육촉진 유용미생물을 지리산 일대의 침엽수와 활엽수 밑의 부엽토(腐葉土)에서 선발하고, 고추에 접종하였을때 고추 묘소질과 생육 및 수량에 미치는 영향에 대한 결과를 요약하면 다음과 같다. 1. 혼합배양결과 Pseudomonas P배지는 $25^{\circ}C$에 Micrococcus sp., Enterobacter agglomerans, Pseudomonas putida, Pseudomonas fluorescens등 4균주, Sabouraud dextrose배지에서는 $35^{\circ}C$에서 Bacillus subtilis, Cellulomonas sp., Bacillus megaterium, Staphylococcus xylosus등 4균주의 생육이 양호하였다. 2. 혼합균주 처리구는 무처리구에 비해 초장, 분지수등은 증가하였고, EC 수준이 높아질수록 초장은 작아진 반면, 분지수는 혼합균주 처리 58일(日) 이후 EC 2.9ds/m에 비해 EC 8.6 dS/m에서 많아지는 경향이었다. 수량은 혼합균주 처리구가 무처리구에 비해 13% 증수되었고, EC 수준이 높아질수록 감소하는 경향이었다. 3. 시험후 토양의 EC, $P_2O_5$, K, Ca, Mg, $NO_3-N$은 EC 수준이 높아질수록 현저하게 증가하는 경향이었으며, 혼합균주 처리구는 무처리구에 비해 OM 및 $NH_4{^+}-N$은 낮은 반면, EC, $P_2O_5$, K, Ca, Mg, $NO_3-N$은 높은 경향이었다. 4. 시험후 혼합균주 처리구는 무처리구에 비해 수분율이 높은 경향이었으며, EC 수준이 높아 질수록 가밀도 수분율, 공극율 등은 증가하는 경향이었다. 5. 혼합균주 처리구는 무처리구에 비해 과실과 엽에서 T-N, $P_2O_5$, $K_2O$, CaO, MgO함량이 높았으며, EC 수준이 높아질수록 $P_2O_5$, $K_2O$, MgO 함량은 증가한 반면, CaO 함량은 낮아지는 경향이었다.

• 한국임상수의학회지
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• 제2권1호
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• pp.115-120
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• 1985

To probe the subclinical mastitis in a herd of cows in Chonnam district, the electrical conductivity(EC) of 825 foremilk samples were measured for 2 years. Normal (n=487) and mastitic(n=110) foremilk samples were classified by the California mastitis test (CMT) and direct somatic cell count(DSCC) and investigated the relations between the changes of the EC value and the calving history, age, days of postpartum, estrus and causative organism isolated. Obtained results are summarized as follows. 1. In the normal foremilk samples, positive correlation, though not significant, was found between the EC value and calving history (r=0.573) and age (r=0.247). 2. In the normal foremilk samples, the EC values were lowered at 30～120 days of postpartum through the whole lactation period and revealed a tendencies to higher values following the day of postpartum increased untill to the drying off (r=0.823), and the days of postpartum was recognized as one of a influencing factor on the EC value(p<0.05). 3. In the mastitic foremilk samples, significant correlation between EC value and resazurin reduction test (RRT) were observed (r=0.904, p<0.05). 4. In the mastitic foremilk samples, EC values were obtained in the E. coli infection as 63.9mM-NaCl, in the Streptococcus spp. infection as 60.5mM-NaCl and in the Staphylococcus spp. infection as 57.0mM-NaCl. 5. At day 0 of estrus, the mean EC values of normal and mastitic foremilk samples were 41.2mM-NaCl and 68.3mM-NaCl respectively and the EC value of day 0 of estrus was higher than that of days before and after estrus.

• 상하수도학회지
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• 제25권5호
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• pp.751-757
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• 2011

The monitoring technique based on electrical conductivity (EC) can provide researchers with some advantages in maintenance management and is cost-effective as compared with existing CSOs monitoring. In this study, the flow rate estimation using EC data was executed in two sites where storm overflow chamber had installed. In the result of A-site, R2 of second order multinomial between dilution ratio of EC and observed flow rate was showed the range of 0.68 ~ 0.77. And $R^{2}$ of B-site was 0.62 ~ 0.81. On the other hand, cumulative frequency of A-site was 43.4 ~ 52.2% in the relative error level of under 20%. And B-site was 10.1 ~ 46.5%. The flow rate estimation formula was improved through consideration of some parameters including antecedent dry days and rainfall duration. And difference between estimated flow rate and observed flow rate in total rainfall event was very small.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.295-298
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• 1998

We have investigated ionic conductivity and electrochemical stability of the electrolytes containing organic solvent. Ion conductivities were measured between 10 and 80$^{\circ}C$, and electrochemical stabilities were determined by cyclic voltammetry on glassy carbon, platinum and aluminum electrodes. Ionic conductivity of electrolyte(EC:DEC=1:1) with IM LiPF$\_$6/ shows better than that of the other electrolytes having Li salts. The IM LiBF$_4$-PC electrolyte exhibits good electrochemical stability. IM LiPF$\_$6/ (EC:DEC=1:1) and IM LiPF$\_$6/ (EC:DMC=1:1) electrolytes are used for the high capacity of battery system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.121-124
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• 1998

The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li secondary battery. This paper describes temperature dependence of conductivity, impedance spectroscopy, electrochemical properties of PVDF electrolytes as a function of a mixed ratio. Polyvinylidene(PVDF) based polymer electrolyte films were prepared by thermal gellification method of preweighed PVDF, plasticizer and Li salt. The conductivity of PVDF electrolytes was 10$\^$-3/S/cm. 25PVDFPC$\_$10/EC$\_$10/LiClO$_4$ electrolyte shows the better conductivity of the others. 25PVDFPC$\_$10/EC$\_$10/LiClO$_4$electrolyte remains stable up to 4.7V vs. Li/Li$\^$+/. Steady state current method and ac impedance used for the determination of transference numbers in PVDFD electrolyte film. The transference number of 25PVDFPC$\_$10/EC$\_$10/LiClO$_4$electrolyte is 0.58.