• 한국농공학회지
• /
• 제16권1호
• /
• pp.3225-3262
• /
• 1974

The purposes of this thesis are to clarify experimentally the variation of ground water temperature in tube wells during the irrigation period of paddy rice, and the effect of ground water irrigation on the growth, grain yield and yield components of the rice plant, and, furthermore, when and why the plant is most liable to be damaged by ground water, and also to find out the effective ground water irrigation methods. The results obtained in this experiment are as follows; 1. The temperature of ground water in tube wells varies according to the location, year, and the depth of the well. The average temperatures of ground water in a tubewells, 6.3m, 8.0m deep are $14.5^{\circ}C$ and $13.1^{\circ}C$, respercively, during the irrigation period of paddy rice (From the middle of June to the end of September). In the former the temperature rises continuously from $12.3^{\circ}C$ to 16.4$^{\circ}C$ and in the latter from $12.4^{\circ}C$ to $13.8^{\circ}C$ during the same period. These temperatures are approximately the same value as the estimated temperatures. The temperature difference between the ground water and the surface water is approximately $11^{\circ}C$. 2. The results obtained from the analysis of the water quality of the "Seoho" reservoir and that of water from the tube well show that the pH values of the ground water and the surface water are 6.35 and 6.00, respectively, and inorganic components such as N, PO4, Na, Cl, SiO2 and Ca are contained more in the ground water than in the surface water while K, SO4, Fe and Mg are contained less in the ground water. 3. The response of growth, yield and yield components of paddy rice to ground water irrigation are as follows; (l) Using ground water irrigation during the watered rice nursery period(seeding date: 30 April, 1970), the chracteristics of a young rice plant, such as plant height, number of leaves, and number of tillers are inferior to those of young rice plants irrigated with surface water during the same period. (2) In cases where ground water and surface water are supplied separately by the gravity flow method, it is found that ground water irrigation to the rice plant delays the stage at which there is a maximum increase in the number of tillers by 6 days. (3) At the tillering stage of rice plant just after transplanting, the effect of ground water irrigation on the increase in the number of tillers is better, compared with the method of supplying surface water throughout the whole irrigation period. Conversely, the number of tillers is decreased by ground water irrigation at the reproductive stage. Plant height is extremely restrained by ground water irrigation. (4) Heading date is clearly delayed by the ground water irrigation when it is practised during the growth stages or at the reproductive stage only. (5) The heading date of rice plants is slightly delayed by irrigation with the gravity flow method as compared with the standing water method. (6) The response of yield and of yield components of rice to ground water irrigation are as follows: \circled1 When ground water irrigation is practised during the growth stages and the reproductive stage, the culm length of the rice plant is reduced by 11 percent and 8 percent, respectively, when compared with the surface water irrigation used throughout all the growth stages. \circled2 Panicle length is found to be the longest on the test plot in which ground water irrigation is practised at the tillering stage. A similar tendency as that seen in the culm length is observed on other test plots. \circled3 The number of panicles is found to be the least on the plot in which ground water irrigation is practised by the gravity flow method throughout all the growth stages of the rice plant. No significant difference is found between the other plots. \circled4 The number of spikelets per panicle at the various stages of rice growth at which_ surface or ground water is supplied by gravity flow method are as follows; surface water at all growth stages‥‥‥‥‥ 98.5. Ground water at all growth stages‥‥‥‥‥‥62.2 Ground water at the tillering stage‥‥‥‥‥ 82.6. Ground water at the reproductive stage ‥‥‥‥‥ 74.1. \circled5 Ripening percentage is about 70 percent on the test plot in which ground water irrigation is practised during all the growth stages and at the tillering stage only. However, when ground water irrigation is practised, at the reproductive stage, the ripening percentage is reduced to 50 percent. This means that 20 percent reduction in the ripening percentage by using ground water irrigation at the reproductive stage. \circled6 The weight of 1,000 kernels is found to show a similar tendency as in the case of ripening percentage i. e. the ground water irrigation during all the growth stages and at the reproductive stage results in a decreased weight of the 1,000 kernels. \circled7 The yield of brown rice from the various treatments are as follows; Gravity flow; Surface water at all growth stages‥‥‥‥‥‥514kg/10a. Ground water at all growth stages‥‥‥‥‥‥428kg/10a. Ground water at the reproductive stage‥‥‥‥‥‥430kg/10a. Standing water; Surface water at all growh stages‥‥‥‥‥‥556kg/10a. Ground water at all growth stages‥‥‥‥‥‥441kg/10a. Ground water at the reproductive stage‥‥‥‥‥‥450kg/10a. The above figures show that ground water irrigation by the gravity flow and by the standing water method during all the growth stages resulted in an 18 percent and a 21 percent decrease in the yield of brown rice, respectively, when compared with surface water irrigation. Also ground water irrigation by gravity flow and by standing water resulted in respective decreases in yield of 16 percent and 19 percent, compared with the surface irrigation method. 4. Results obtained from the experiments on the improvement of ground water irrigation efficiency to paddy rice are as follows; (1) When the standing water irrigation with surface water is practised, the daily average water temperature in a paddy field is 25.2$^{\circ}C$, but, when the gravity flow method is practised with the same irrigation water, the daily average water temperature is 24.5$^{\circ}C$. This means that the former is 0.7$^{\circ}C$ higher than the latter. On the other hand, when ground water is used, the daily water temperatures in a paddy field are respectively 21.$0^{\circ}C$ and 19.3$^{\circ}C$ by practising standing water and the gravity flow method. It can be seen that the former is approximately 1.$0^{\circ}C$ higher than the latter. (2) When the non-water-logged cultivation is practised, the yield of brown rice is 516.3kg/10a, while the yield of brown rice from ground water irrigation plot throughout the whole irrigation period and surface water irrigation plot are 446.3kg/10a and 556.4kg/10a, respectivelely. This means that there is no significant difference in yields between surface water irrigation practice and non-water-logged cultivation, and also means that non-water-logged cultivation results in a 12.6 percent increase in yield compared with the yield from the ground water irrigation plot. (3) The black and white coloring on the inside surface of the water warming ponds has no substantial effect on the temperature of the water. The average daily water temperatures of the various water warming ponds, having different depths, are expressed as Y=aX+b, while the daily average water temperatures at various depths in a water warming pond are expressed as Y=a(b)x (where Y: the daily average water temperature, a,b: constants depending on the type of water warming pond, X; water depth). As the depth of water warning pond is increased, the diurnal difference of the highest and the lowest water temperature is decreased, and also, the time at which the highest water temperature occurs, is delayed. (4) The degree of warming by using a polyethylene tube, 100m in length and 10cm in diameter, is 4~9$^{\circ}C$. Heat exchange rate of a polyethylene tube is 1.5 times higher than that or a water warming channel. The following equation expresses the water warming mechanism of a polyethylene tube where distance from the tube inlet, time in day and several climatic factors are given: {{{{ theta omega (dwt)= { a}_{0 } (1-e- { x} over { PHI v })+ { 2} atop { SUM from { { n}=1} { { a}_{n } } over { SQRT { 1+ {( n omega PHI) }^{2 } } } } LEFT { sin(n omega t+ { b}_{n }+ { tan}^{-1 }n omega PHI )-e- { x} over { PHI v }sin(n omega LEFT ( t- { x} over {v } RIGHT ) + { b}_{n }+ { tan}^{-1 }n omega PHI ) RIGHT } +e- { x} over { PHI v } theta i}}}}{{{{ { theta }_{$\infty$ }(t)= { { alpha theta }_{a }+ { theta }_{ w'} +(S- { B}_{s } ) { U}_{w } } over { beta } , PHI = { { cpDU}_{ omega } } over {4 beta } }}}} where $\theta$$\omega$; discharged water temperature($^{\circ}C$) $\theta$a; air temperature ($^{\circ}C$) $\theta$$\omega$';ponded water temperature($^{\circ}C$) s ; net solar radiation(ly/min) t ; time(tadian) x; tube length(cm) D; diameter(cm) ao,an,bn;constants determined from $\theta$$\omega$(t) varitation. cp; heat capacity of water(cal/$^{\circ}C$ ㎥) U,Ua; overall heat transfer coefficient(cal/$^{\circ}C$ $\textrm{cm}^2$ min-1) $\omega$;1 velocity of water in a polyethylene tube(cm/min) Bs ; heat exchange rate between water and soil(ly/min)

• Journal of Forest and Environmental Science
• /
• 제28권4호
• /
• pp.232-241
• /
• 2012

We investigated the relationship between vegetation type and soil carbon dynamics in even-aged alder (Alnus hirsuta) and Korean pine (Pinus koraiensis) plantations in central Korea. Both forests were located on the same soil parent material and occupied similar topographic positions. Soil $CO_2$ efflux in the two plantations was determined using a dynamic chamber method accompanied by measurements of soil moisture content and temperature. Mean soil temperature was similar in the two plantations, but mean soil water content was significantly higher in the alder plantation than in the pine plantation. In both plantations, seasonal patterns in soil $CO_2$ efflux exhibited pronounced variation that corresponded to soil temperature. Soil water content did not affect the seasonal variation in soil $CO_2$ efflux. However, in summer, when soil temperature was above $17^{\circ}C$, soil $CO_2$ efflux increased linearly with soil water content in the alder plantation. Estimated $Q_{10}$ was 3.3 for the alder plantation and 2.7 for the pine plantation. Mean soil respiration during the measurement period in the alder plantation was 0.43 g $CO_2\;m^{-2}\;h^{-1}$, which was 1.3 times higher than in the pine plantation (0.33 g $CO_2\;m^{-2}\;h^{-1}$). Higher soil $CO_2$ efflux in the alder plantation might be related to nitrogen availability, particularly the concentration of $NO_3{^-}$, which was measured using the ion-exchange resin bag method.

• 한국어류학회지
• /
• 제26권4호
• /
• pp.322-330
• /
• 2014

2011년 9월부터 2012년 8월까지 경상남도 고성에 있는 4개 하천의 환경 특성을 파악하고, 각 하천의 어류상과 어류군집을 조사하였다. 채집된 어류는 고성천 17종, 마암천 18종, 구만천 20종, 배둔천 15종의 어류가 채집되었다. 집괴 분석 결과 해수 영향 유무에 따라 A 그룹은 구만천, 마암천, B 그룹은 고성천, 배둔천의 2 그룹으로 구분되었다. A 그룹에는 민물검정망둑(Tridentiger brevispinis), 날망둑(Gymnogobius castaneus), 숭어(Mugli cephalus), 문절망둑(Acanthogobius flavimanus)과 같은 주연성 어류들이 출현하였지만, B 그룹은 출현하지 않거나 소수만 출현하였다. 반면에 B 그룹에 출현한 참붕어 (Pseudorasbora parva), 긴몰개 (Squalidus gracilis majimae), 참갈겨니 (Zacco koreanus)와 같은 1차 담수 어류들은 A 그룹에 소수만 출현하였다. A 그룹의 하천은 하구둑이 없어서 담수와 해수 유통이 원활한 자연적인 하류지역이며, B 그룹은 하구둑이나 수중보에 의해 담수와 해수의 소통에 영향을 받는 곳이다. 결과적으로 하구둑과 수중보와 같은 인위적인 요인에 의한 담수와 해수 흐름의 변화가 고성인근 하천의 어류상에 영향을 미친 것으로 생각된다.

• 상하수도학회지
• /
• 제30권4호
• /
• pp.449-457
• /
• 2016

In this study, the effectiveness of electrodialysis in removing inorganic arsenic from groundwater was investigated. To evaluate the feasibility of the electrodialysis, operating parameters such as treatment time, feed concentration, applied voltage and superficial velocity were experimentally investigated on arsenic removal. The higher conductivity removal and arsenic removal efficiency were obtained by increasing applied voltages and operation time. An increase of salinity concentrations in arsenic polluted groundwater exerted no effects on the arsenic separation ratios. Arsenic polluted waters were successfully treated with stack voltages of 1.8 ~ 2.4 V/cell-pair to approximately 93.4% of arsenic removal. Increase flow rate in diluate cell gave positive effect to removal rate. However, increase of superficial velocity in the concentrated cell exerted no effects on either the conductivity reduction or on the separation efficiency. Hopefully, this paper will provide direction in selecting appropriate operating conditions of electrodialysis for arsenic removal.

• Asian Journal of Atmospheric Environment
• /
• 제6권4호
• /
• pp.259-267
• /
• 2012

To clarify the effects of black carbon (BC) particles on growth and gas exchange rates of Asian forest tree species, the seedlings of Fagus crenata, Castanopsis sieboldii, Larix kaempferi and Cryptomeria japonica were exposed to BC particles with sub-micron size for two growing seasons from 1 June 2009 to 11 November 2010. The BC particles deposited after the exposure to BC were observed on the foliar surface of the 4 tree species. At the end of the experiment, the amount of BC accumulated on the foliar surface after the exposure to BC aerosols were 0.13, 0.69, 0.32 and 0.58 mg C $m^{-2}$ total leaf area in F. crenata, C. sieboldii, L. kaempferi and C. japonica seedlings, respectively. In August 2010, the exposure to BC particles did not significantly affect net photosynthetic rate under any light intensity, stomatal diffusive conductance to water vapour ($g_s$), stomatal limitation of photosynthesis, response of $g_s$ to increase in vapour pressure deficit and leaf temperature under light saturated condition in the leaves or needles of the seedlings. These results suggest that the BC particles deposited on the foliar surface did not reduce net photosynthesis by shading, did not increase leaf temperature by absorption of irradiation light, and did not induce plugging of stomata in the leaves or needles of the seedlings. There were no significant effects of BC particles on the increments of plant height and stem base diameter during the experimental period and the whole-plant dry mass at the end of the experiment. These results indicate that the exposure to BC particles with sub-micron size for two growing seasons did not significantly affect the growth and leaf or needle gas exchange rates of F. crenata, C. sieboldii, L. kaempferi and C. japonica seedlings.

• 분석과학
• /
• 제12권2호
• /
• pp.111-115
• /
• 1999

간접자외선흡광검출 이온크로마토그래피를 7가지 음이온($H_2PO_4^-$, $Cl^-$, $NO_2^-$, $NO_3^-$, $I^-$, $SO_4^{2-}$, $SCN^-$)분리에 적용하였다. 컬럼은 저용량의 강염기성 음이온 교환체를 가진 상용화된 TSK-guardgel QAE-SW (ca. 0.3 meq./g; 4.6 mm i.d${\times}$150 mm)를 사용하였다. 선택적이고 신속한 이온분리방법을 연구하기 위하여 naphthalene trisulfonic acid(NTS) 및 naphthalene disulfonic acid(NDS) 용리액에 대한 분리거동을 조사하였다. 더 나아가, 0.20 mM NTS 용리액에 5% 아세토리트릴을 첨가하여 음용수에 적용한 결과, 양이온과 음이온을 동시에 분리 할 수 있었다.

• 전기화학회지
• /
• 제14권1호
• /
• pp.9-15
• /
• 2011

The composite membranes comprising of sulfonated polymers as matrix and ionic liquids as ion-conducting medium in replacement of water are studied to investigate the effect of annealing of the sulfonated polymers. The polymeric membranes are prepared on recast Nafion containing the ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate ($EMIBF_4$). The composite membranes are characterized by thermogravitational analyses, ion conductivity and small-angle X-ray scattering. The composite membranes annealed at $190^{\circ}C$ for 2 h after the fixed drying step showed better ionic conductivity, but no significant increase in thermal stability. The mean Bragg distance between the ionic clusters, which is reflected in the position of the ionomer peak (small-angle scattering maximum), is larger in the annealed composite membranes containing $EMIBF_4$ than the non-annealed ones. It might have been explained to be due to the different level of ion-clustering ability of the hydrophilic parts (i.e., sulfonic acid groups) in the non- and annealed polymer matrix. In addition, the ionic conductivity of the membranes shows higher for the annealed composite membranes containing $EMIBF_4$. It can be concluded that the annealing of the composite membranes containing ionic liquids due to an increase in ion-clustering ability is able to bring about the enhancement of ionic conductivity suitable for potential use in proton exchange membrane fuel cells (PEMFCs) at medium temperatures ($150-200^{\circ}C$) in the absence of external humidification.

• 한국환경농학회지
• /
• 제16권2호
• /
• pp.193-198
• /
• 1997

본 연구에서 얻을 수 있었던 결과를 요약하면 다음과 같다. 1. 황산이온 농도를 포함해 원수의 음이온 농도가 낮은 경우 질산이온을 효율적으로 제거하기 위해 사용가능한 수지는 일반적으로 사용되는 Type 1수지보다도 공극형태가 gel 형태인 Type 2수지를 사용하는 것이 적절할 것으로 판단된다. 그러나 음이온 농도가 높은 지하수나 빠른 유속으로 처리할 경우 공극형태가 macroporous인 것이 유리할 것으로 판단된다. 또한 원수의 항산이온 농도가 낮은 경우에는 같은 macroporous 형태의 수지라도 IRA-900 같은 일반 형태의 수지가 질산이온 선택성 수지보다도 효율이 좋은 것으로 나타났다. 2. Type 2 수지를 사용하여 얻은 자료로 동력학적 접근 방정식에 적용하여 얻은 결과를 다중희귀분석한 결과 다음과 같은 식을 도출할 수 있었다. $logq_0$=-0.14logV-0.148logH-1.04(r=0.99) logM=0.135logV+0.151logH+1.814(r=0.99) 3. 황산이온 농도가 다소 높은 지하수를 처리할 때는 일반형태인 IRA-900보다도 질산이온 선택성 수지인 IMAC HP-555 수지가 효율이 좋은 것으로 나타나 원수의 황산이온 농도가 50mg/l 이상일 경우에는 질산이온 선택성 수지를 사용하는 것이 바람직할 것으로 판단된다.

• 미생물학회지
• /
• 제1권1호
• /
• pp.48-50
• /
• 1963

청량음료 제조적 외부로 부터 얼마나 오염이 되며 또 가장 큰 오염원은 무엇인가를 알아보기 위해 제조공정중의 각 단계별로 또 생업에 쓰이는 박과와 원과별로 윤도가 되는 총생균수를 검토하였으며 이들 얻은 결과는 다음과 같았다. 1) 생업에 쓰이는 박과와 원과중 가장 큰 제조과는 연평적 ml당 4개이었으며 동계에서는 ml당 1개정과이던 것이 하계에서는 ml당 8개과정가 검출되었다. 3)제품에서는 일년문 coliform group이 검출된 적이 거의 없었다. 4)물의 이온문환지를 통과하여도 총생균자의 약화는 거의 측정할 수 없었다. 5)제품에서 HIST를 사용한 후 사용 안할 때보다 1/8의 오염과감소를 나타냈다

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제22권3호
• /
• pp.10-17
• /
• 2017

In this study, the evolution and origin of major dissolved constituents of crystalline bedrock groundwater in a coastal area were evaluated using multivariate statistical and groundwater quality analyses. The groundwater types mostly belonged to the $Na(Ca)-HCO_3$ and $Ca-HCO_3$ types, indicating the effect of cation exchange. Stable isotopes of water showed two areas divided by first and secondary evaporative effects, indicating a pattern of rapid hydrological cycling. Saturation indices of minerals showed undersaturation states. Thus, the degree of evolution of groundwater is suggested as in the low to intermediate stage, based on field and laboratory analytical conditions. According to the principal component analysis (PCA) results, the chemical components of EC, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $HCO_3{^-}$, $SO{_4}^{2-}$ (PCA 1), $F^-$ (PCA 3), $SiO_2$ (PCA 4), and $Fe^{2+}$ (PCA 5) are derived from various water-rock interactions. However, $NO_3{^-}$, $Na^+$, and $Cl^-$ (PCA 2) represented the chemical characteristics of both anthropogenic sources and natural sea spray.