• Journal of Ecology and Environment
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• v.36 no.1
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• pp.19-29
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• 2013

Cicuta virosa is an endangered species in Korea, which is a southern marginal area. To conserve and restore habitats of this plant, we investigated water and soil environmental characteristics and vegetation at four habitats during the growing season. The C. virosa habitats differed in community structure, water and substrate properties, and water regime. Although the total distribution ranges of the water and soil environments for C. virosa were wide and overlapped with the optimal environmental range of distribution of accompanying species, the optimal water level range for C. virosa was defined as $7{\pm}3.5$ cm. Water level was adjusted by substrate structure such as a mound of P. japonica and a floating mat comprised of accompanying species. A floating mat was an aid to maintain an optimal and stable water level in deep or fluctuating water and to prevent strong competition with prolific macrophytes. The GS sampling site, which had floating mats, could be a good model for C. virosa conservation in a warm temperate region, whereas the PC sampling sites, which experienced a water shortage in spring, provided a clue about the decline in C. virosa population size.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2003.10a
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• pp.170-173
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• 2003

Activated Rice-Hull carbon was developed to remove ammonia compounds in water matrix. Isotherm adsorption tests of ammonia were conducted using a bottle-point technique and column test. Residual ammonia after Jar-Test or passing through the column was determined by Indophenol method, and assessed the removal efficiency for ammonia of the adsorbent. As a result, the adsorption capacity for ammonia of activated racehull carbon was very larger than that of coconut shell carbon, because the rice hull carbon had the higher BET surface area of silicate. The activated racehull carbon is under the development as adsorbent to remove ammonia in drinking water and waste water.

• Journal of the Korean Chemical Society
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• v.63 no.4
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• pp.233-236
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• 2019

In this study, the solvolysis of cyclohexanesulfonyl chloride (1) was studied by kinetics in ethanol-water, methanol-water, acetone-water, and 2,2,2-trifluoroethanol (TFE)-water binary solvent systems. The rate constants were applied to the extended Grunwald-Winstein equation, to obtain the values of m = 0.41 and l = 0.81. These values suggested $S_N2$ mechanism in which bond formation is more important than bond breaking in the transition state (TS). Relatively small activation enthalpy values (11.6 to $14.8kcal{\cdot}mol^{-1}$), the large negative activation entropy values (-29.7 to $-38.7cal{\cdot}mol^{-1}{\cdot}K^{-1}$) and the solvent kinetic isotope effects (SKIE, 2.29, 2.30), the solvolyses of the cyclohexanesulfonyl chloride (1) proceeds via the $S_N2$ mechanism.

• Journal of Ecology and Environment
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• v.42 no.4
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• pp.220-227
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• 2018

Background: To understand the ecological characteristics of floating mat in which endangered species of Iris laevigata and Menyanthes trifoliata inhabit, we surveyed the vegetation and water environments of a floating mat wetland and examined the relations between ecological characteristics of the mat. Results: Although Phragmites australis and Zizania latifolia were found at all experimental quadrats (n = 61) as the major vegetational components of the floating mat wetland, they showed relatively poor growth performances in terms of shoot height (< 2 m) and biomass production (<$300g/m^2$) compared with those in soil-based wetlands because of oligotrophic water condition. The competitiveness and distribution of P. australis and Z. latifolia seemed to be determined by water level difference by micro-topography rather than water chemistry. Conclusion: P. australis and endangered plant species mainly occurred in the area of relatively shallow water, whereas Z. latifolia and deep-water species such as Scirpus fluviatilis mostly inhabit in the area of deep water on the floating mat. Continuously maintained water level and oligotrophic water condition in the floating mat appeared to be important environments for endangered species such as I. laevigata and M. trifoliata.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.1
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• pp.72-88
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• 2006

The optimal environmental ranges of the establishment phase for the distribution of Zizania latifolia and Typha angustifolia was determined to develop a set of basic data and criteria of planting substrate for the restoration, conservation and management of wetlands. The study was carried at 17 wetlands in the Kyunggi-do and Gyeongsangnam-do region where inland wetlands place intensively in June, 2005. Total 127 quadrats were sets in growing areas of Zizania latifolia and Typha angustifolia. $NO_3-N$, K, Ca, Mg and Na in the water variables and soil texture, LOI (loss on ignition), soil pH and soil conductivity in the soil variables were analyzed. The optimal range of water depth for the distribution of Zizania latifolia was -5~39cm, $NO_3-N$ content of water was <0.01~0.19ppm, K content of water was 0.1~5.9ppm, Ca content of water 0.5~44.9ppm, Mg content of water was 1.2~11.9ppm, Na content of water 3.4~29.9ppm, water conductivity was 48~450${\mu}S$/cm, respectively. The optimal range of LOI for the distribution of Zizania latifolia was 1.7~11.9%, soil conductivity was 25.5~149.9${\mu}S$/cm, respectively. The optimal range of water depth for the distribution of Typha angustifolia was -20~24cm, $NO_3-N$ content of water was <0.01~0.19ppm, K content of water was 0.2~2.9ppm, Ca content of water 0.6~19.9ppm, Mg content of water was 0.2~5.9ppm, Na content of water 3.5~19.9ppm, water conductivity was 96~450${\mu}S$/cm, respectively. The optimal range of LOI for the distribution of Typha angustifolia was 2.4~15.9%, soil conductivity was 17.6~149.9${\mu}S$/cm, respectively. The optimal soil texture were loam, silt loam and sandy loam in both species. The lower water depth (-20~40cm) is appropriate to increase biodiversity in both species dominated community and it is better to maintain water depth of 40~100cm for water purification. Both species appear frequently in the soil with high silt content.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.1
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• pp.15-26
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• 2023

This study aimed to evaluate the performance of water level classification from CCTV images in agricultural facilities such as reservoirs. Recently, the CCTV system, widely used for facility monitor or disaster detection, can automatically detect and identify people and objects from the images by developing new technologies such as a deep learning system. Accordingly, we applied the ResNet-50 deep learning system based on Convolutional Neural Network and analyzed the water level of the agricultural reservoir from CCTV images obtained from TOMS (Total Operation Management System) of the Korea Rural Community Corporation. As a result, the accuracy of water level detection was improved by excluding night and rainfall CCTV images and applying measures. For example, the error rate significantly decreased from 24.39 % to 1.43 % in the Bakseok reservoir. We believe that the utilization of CCTVs should be further improved when calculating the amount of water supply and establishing a supply plan according to the integrated water management policy.

• Journal of The Korean Association For Science Education
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• v.28 no.1
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• pp.24-31
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• 2008

This study aims at examining the concepts that apply in understanding the water cycle, to inquire into the concept related to the unit of earth structure that are taught in the Earth Science I. Analysis of word association, drawing and questionnaires showed that it was difficult for them to understand the water cycle within the earth system, and to put components into one integrated system together. In other words, it showed that they have a low standard of understanding in connection with the water cycle, that their understanding of water cycle are simple thoughts rather than systematic thought. It showed that they had an understanding of the atmosphere and hydrosphere to some extent, but they took no notice of the effect of the lithosphere or biosphere, nor do they have an understanding of its effect. Analysis of questionnaires showed that they have no well understanding of water cycle of cyclic nature, and that they have low standard of understanding of the components of water cycle.

• Journal of Korean society of Dental Hygiene
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• v.11 no.4
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• pp.547-556
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• 2011

Objectives : The purpose of this study was to examine the relationship between the infection control education experiences of dental hygienists and the state of their infection control. Methods : The subjects in this study were the dental hygienists who worked in Seoul. The relationship of their infection control education experiences to their gender, marital status, academic credential, workplace, length of service, infection control implementation, experience of being exposed to infection, way of coping with it, hand washing, use of personal protection devices and equipment management was analyzed. Results : It is found that the variable to affect the state of infection control was educational experiences about handpiece water pipe management, ultrasonic scaler water pipe management and three-way syringe water pipe management. Conclusions : Dental hygienists who are one of major dental personnels should receive systematic education on infection control to acquire accurate knowledge to ensure the successful prevention of cross infection.

• The Journal of Korean Society for School & Community Health Education
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• v.1 no.2
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• pp.87-104
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• 2000

The purpose of this study was to obtain the basic data as a improvement method through the fact-revealing concerning the drinking water management of school and utilization of student. The problems of the research are as follows: First, to investigate status of management of drinking water by area and school. Second, to investigate student's utilization of drinking water by area and school. 1,400 students was selected at 45 elementary and middle-high schools located in Kang-won province, and this study was constituted of two questionnaires(for school's questionnaire and student's questionnaire). The results was analyse through the frequency analysis, $x^2$-test on the basis of the above research problem by SPSS program. The findings of this research are as follows; 1) The Management of School Drinking Water First, the source of school drinking water was mostly piped water. Inspection of water quality has been fulfilled under four times a year, in the other hands, from the result inspection, the schools which was given inadequate determination was 22.2%. Second, reservoir cleaning and hygiene inspection failed far short of the regulations. Especially, reservoir cleaning was managed by exterior consignment industry not low-level officials. Third, school water drinking was the most supplied through the type of water purifier. Water purifier has been distributed to city-located and middle-high school highly, factually the water from water purifier was served with water cup. Fourth, the selection standard of water drinking manager showed slightly differently by school, accordingly there need to develope integrated system with the respective to its effective systematic management. Fifth, water cup was mostly treated by only water clear, which is to vindicate the problems concerning hygiene management. 2) Utilization of school student on Drinking Water First, Disbelief on drinking water of school student was very high. Especially, proportion of middle-high school student's disbelief of drinking water was higher than elementary school student, also girls higher than boys. Many of student have heard to don't drink water from around people. And there were showed meaningful differences by area and school. Second, It was showed many student recognize had to utilize water purifier, boiled water. However, they have still drunken the tap water or portable water from their home. Third, Many of student showed negative response with the respective to the management conditions of drinking water in classroom, There were showed meaningful differences by area and school. From the fact-revealing of water cup management, Students mostly answered to 'only water clear' and the answer of 'None use' or 'With personal cup' was higher. Fourth, In bad experience of Drinking Water, student mostly answered to 'occasionally' and there were showed meaningful differences by school. student's disease experience with school drinking water was few and there were showed meaningful differences by area and gender.

• Journal of Environmental Science International
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• v.21 no.8
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• pp.909-929
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• 2012

It is an after-school material for elementary school student based on STEAM education which has a theme of water pollution as a global issue. First of all, we take a look at various ways of measuring water pollution and among them, we include experiment for student to know about the water pollution by using indicator organisms. Next, we examine how some elements in our daily life affect on water and provide class with systematically technological and engineering solution. With this text book, we let the student recognize environmental problem and seek for the solution about it. Therefore, it helps student to connect with stream of thought.