• Title/Summary/Keyword: 토의방법

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Synthesis of Artificial Zeolite from Fly Ash for Preparing Nursery Bed Soils and the Effects on the Growth of Chinese Cabbage (석탄회(石炭灰)를 이용한 육묘(育苗) 상토용(床土用) 인공(人工) 제올라이트의 제조와 배추 생육에 미치는 효과(效果))

  • Kim, Yong-Woong;Lee, Hyun-Hee;Yoon, Chung-Han;Shin, Bang-Sup;Kim, Kwang-Sik
    • Korean Journal of Soil Science and Fertilizer
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    • v.31 no.2
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    • pp.95-106
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    • 1998
  • To reduce the environmental contamination and to utilize fly ash massively produced from the coal power plant every year, we synthesized the artificial zeolite using fly ash treated with alkaline, and then analyzed the mineralogical and morphological properties by X-ray, IR, and SEM. The amount of $NH_4{^+}$, $K^+$, and $H_2PO_4{^-}$ adsorbed by the fly ash and the artificial zeolite were determined with reaction time, amount of adsorbate used, ion concentrations. The results obtained from the pot experiments packed with the top soil, amended with granulated artificial zeolite which was made by treatment of 4% polyvinylalcohol, showed that CEC of the artificial zeolite was $257.7cmol^+kg^{-1}$, that was almost 36 times greater than that of fly ash. The ratio of $SiO_2/Al_2O_3$ decreased but the amount of Na increased. The physico-chemical properties analyzed by X-ray, IT, and SEM represented that the artificial zeolite synthesized had a similar morphological structure to that of the natural zeolite. The structures of the artificial zeolite had a significantly enlarged surface having a lot of pores, while the fly ash looked like spherical smooth shape with having not pores on the surface. Thus, the artificial zeolite was successfully synthesized. The results of adsorption isotherms of fly ash and artificial zeolite showed that the amount of $NH_4{^+}$, $K^+$, and $H_2PO_4{^-}$ adsorbed increased as the equilibrium concentration increased, while $NH_4{^+}$ was strongly adsorbed on the surface of fly ash and artificial zeolite than that of $K^+$. The most distinctive growth of Chinese cabbage was found from the top soil(NPK + soils + 20% of granulated artificial zeolite + 5% of compost). Therefore, we concluded that one of the most effective methods to effectively recycle a fly ash was to make the artificial zeolite as we did in this experiment.

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Studies on the Cause and Control for Non-sprouting Bud in the Utility Reclaimed Hill Side Mulberry Field. (개간지 상전에 발생하는 발아불량 현상의 원인 및 방제에 관한 연구)

  • 유근섭
    • Journal of Sericultural and Entomological Science
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    • v.16 no.1
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    • pp.1-20
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    • 1974
  • These studies are conducted to find out inducing factors for the non-sprouting bud which appears in the utility reclaimed hill mulberry held and to establish control method for it since 1971. The results are as follows: 1. In spring, winter bud does not germinate at all on the top of branches or does wither suddenly after or during its germination. Necrosis and browning are appeared in cortex and phloem of non-sprouting bud branch. In autumn, the deterioration of leaves, the abnormal leaves on the top of branch, and browning of veins or petioles are also observed. 2. The soil of non-sprouting bud mulberry Held were found to be sand loom derived from granite rocks. The sub soil of it was very poor in development of root system because it had hard soil and lower pore space ratio. Especially, the sub soil to bring about severe non-sprouting bud had been easily appeared with deficiency of moisture content because of high density solid. 3. Content of soil moisture was significantly lower in the severe non-sprouting bud soil than in the healthy field. The sub soil o( the healthy field contained proper moisture content. On the other hand, the sub soil of the severe non-sprouting bud held contained almost critical moisture content for wilting. 4. The depth of available soil was shallow in the non-sprouting bud than in the healthy fold. The more rate of the non-sprouting bud was severe, the more available soil depth was sallow. 5. Available boron content in soil was affected by moisture content in soil. There was. lower moisture content in the non-sprouting bud field than that in healthy fold during 5, June to 5, September. 6. There was no significant correlation between soil pH and available boron content. On the other hand, the correlation of the content of organic matter and available boron content appeared to be highly positive significance. 7. The quantity of boron was significantly contained more in healthy mulberry field (0.34∼0.43ppm) than in non-sprouting bud field (0.10∼0.28ppm). 8. Boron content in leaves and barks was significantly lower in the non-sprouting bud trees than in healthy trees. 9. The symptom of non-sprouting bud induced from boron free sand culture was similar with that arised in the non-sprouting bud field. 10. The rate of non-sprouting bud was high by the increased application of lime. Considering the facts mentioned the above, author may conclude that the non-sprouting bud of mulberry tree is caused by boron deficiency, but also it is affected by the parent rocks, organic matter, soil moisture content and lime application. 11. The non$.$sprouting bud may be completely controlled by the application of 6∼9kg borax per 10a mulberry field twice a year in spring and summer.

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A Survey of Perceptions of Elementary School Teachers on the Small-Scale Chemistry (미량화학(Small-Scale Chemistry)에 대한 초등학교 교사들의 인식)

  • Kim, Sung-Kyu;Kong, Young-Tae
    • Journal of Science Education
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    • v.34 no.2
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    • pp.291-305
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    • 2010
  • The aim of this study was to survey the perceptions of the elementary school teachers on the smallscale chemistry(SSC) following its training session. The teachers participating in the survey were 266 teachers in the Gyeongnam province. They were given a questionnaire that focused on the nine areas of the SSC: Needs for the teacher training and its application, its benefits, issues of safety and danger as well as treatment of environmental pollution, its economic efficiency and the development of investigative skills. The designed questionnaire was checked by an authority, and the responses to each question were tallied and analyzed. The results are as follows. The biggest problems of the traditional experimental methods as rated by the teachers were, in the order of importance, the preparation time, the legal liability of teachers for the safety and accidents, financial issues, disposal of the experimental wastes and the lack of relevant data. Since most of the teachers had not experienced the SSC lab programs in the field, they responded positively to the questions of need for its introduction and training. The implementation of the experimental SSC lab programs should proceed in the following order: introduction into the textbook, teacher training program, after-school education and the invitation of instructors. The most useful materials for the SSC program were CDs, videos, books and various printed materials, in that order. The responses regarding benefits of the SSC program included its simplicity, convenience, time savings, diversity, qualitative and quantitative aspects, integration into the regular class and use of toys. In particular, the teachers mentioned the increased safety due to the small amount of experimental reagents needed and the durability of plastic instruments. The familarity from the use of everyday tools as well as easy access to and the low-cost of the instruments were other important benefits. The teachers in general rated the educational content of the program highly, but many also found it to be average. Some pointed out the lack of sufficient discussion due to the individual or pair groupings as a potential shortcoming. The potential for development of problem solving ability and improvement of skills was rated positively. The number of teacher who rated the development of creativity positively was just over the half. As for the area of improving investigative skills, many found its assessment difficult and confusing because of the lack of its systemic definition and categorization. Based on the findings of this study, I would like to recommend the application and a wider dissemination of the small-scale chemistry lab program into the elementary school science curriculum.

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Effect of Several Application Methods of Yakto on Growth Status of Aerial Parts in Ginseng Seedlings (약토 시용방법이 인삼 양직묘 지상부 생육에 미치는 영향)

  • Lee, Sung-Sik;Cheon, Seong-Ki;Lee, Tae-Su;Yoon, Jong-Hyuk;Park, Hyeon-Suk;Shin, Seong-Lyon;Choi, Kwang-Tae;Lee, Gab-Soo;Ju, Seong-Don;Chung, Jae-Dong
    • Journal of Ginseng Research
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    • v.28 no.4
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    • pp.201-206
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    • 2004
  • This experiment was conducted to determine the economic application method of Yakto among 6 application method : amount of Yakto application $3\;plot(70\;l,\;25.5\;l,\;13,3\;l/kan;\;180cm{\times}90cm),$ and added side dressing(3 l/kan) each plot. The reduced amoumt of Yakto application(25.5 l, 13.3 l/kan) were lower the contents of inorganic nitrogen, $P_{2}O_{5},\;K,\;Ca$ and Mg, but similar pH in bed soil compared with standard Yakto application(70 l/kan). Side dressing applicated on 29 May increased the contents of inorganic nitrogen, $P_{2}O_{5},\;K,\;Ca,\;Mg$ and salt concentration in bed soil compared with non­side dressing in each Yakto application plot(70 l, 25.5 l, 13,3 l/kan). The reduced amoumt of Yakto application(25.5 l/kan) added side dressing(3 l/kan) were similar the contents of inorganic nitrogen, K, Mg and salt but lower $P_{2}O_{5}$ and Ca in bed soil compared with standard Yakto application(70 l/kan) in June. The reduced amoumt of Yakto application(25,5 l/Kan) added side dressing(3 l/kan) was similar the contents of P, K, Ca and Mg but lower N in leaves compared with standard Yakto application(70 l/kan). The reduced amoumt of Yakto application(25.5 l/kan) added side dressing(3 l/kan) was shorter stem length, and higher $5{\%}$ chlorosis of leaf tip, but similar emergence ratio, survival ratio, leaf senescence ratio, chlorophyll, stem diameter and leaf area compared with standard Yakto application(70 l/kan). These suggested that 25.5 l Yakto application added side dressing(3 l/kan) per kan might be possible economical application method of Yakto.

Development and Evaluation of the PBL Teaching/Learning Process Plan of 'Housing Culture and Practical Space Use' for Home Economics in Middle School (중학교 가정과 문제 중심 '주생활 문화와 주거 공간 활용' 교수·학습 과정안 개발과 평가)

  • Cho, Jiwon;Cho, Jaesoon
    • Journal of Korean Home Economics Education Association
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    • v.32 no.2
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    • pp.59-76
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    • 2020
  • The purpose of this study was to develop and evaluate the teaching/learning process plan of 'housing culture and practical space use' for home economics in middle school according to the problem based learning(PBL) model. The plan consisting of 4-lessons has been developed and implemented following the steps of ADDIE model. Various activity materials (4 scenarios, 6 individual activity sheets, 10 reading texts, and 5 working resources) and visual materials (4 sets of ppt and 4 moving pictures) as well as questionnaire were developed for the 4-session lessons. The plans were implemented to a single class of 21 junior students at H middle school in rural area, Kyeongnam, from 1st to 12th of April, 2019. Students highly enjoyed and were satisfied with the whole 4-lessons in aspects such as understanding of the contents, adequacy of materials and activities, and usefulness in one's own daily life. Additionally, they have more actively participated in the lessons than usual and even interested in learning more of such lessons. Students also reported that they highly accomplished the goal of each lesson as well as overall objectives. They showed interest in the major part of PBL lesson such as scenario and group activities. And they engaged themselves in drawing the share housing space plan with '5D planner' web program which they described as the best part of the lessons. The teaching/learning process plan developed in this study may be used as a theme of maker education, which is emerging these days. It can be concluded that the PBL teaching/learning process plans for 'housing values and practical space use' would contribute to improving students' attitude on living with others and ability to manage one's individual life.

An Evaluation of the Use of Statistical Methods in the Journal of Tuberculosis and Respiratory Diseases ([결핵 및 호흡기질환] 게재 논문의 통계적 기법 활용에 대한 평가)

  • Koh, Won-Jung;Lee, Seung-Joon;Kang, Min Jong;Lee, Hun Jae
    • Tuberculosis and Respiratory Diseases
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    • v.57 no.2
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    • pp.168-179
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    • 2004
  • Background : The statistical analysis is an essential procedure ensuring that the results of researches are based on evidences rather than opinion. The purpose of this study is to evaluate which statistical techniques are used and whether these statistical methods are used appropriately or not in the journal of Tuberculosis and Respiratory Diseases. Materials and Methods : We reviewed 185 articles reported in the journal of Tuberculosis and Respiratory Diseases in 1999. We evaluated the validity of used statistical methods based upon the checklist that was developed on the basis of the guideline for statistical reporting in articles for medical journals by International Committee of Medical Journal Editors. Results : Among 185 articles, original articles and case reports were 110 (59.5%) and 61 (33.0%) respectively. In 112 articles excluding case reports and reviews, statistical techniques were used in 107 articles (95.5%). In 94 articles (83.9%) descriptive and inferential methods were used, while in 13 (11.6%) articles only descriptive methods were used. With the types of inferential statistical techniques, comparison of means was most commonly used (64/94, 68.1%), followed by contingency table (43/94, 45.7%) and correlation or regression (18/94, 19.1%). Among the articles in which descriptive methods were used, 83.2% (89/107) showed inappropriate central tendency and dispersion. In the articles in which inferential methods were used, improper methods were applied in 88.8% (79/89) and the most frequent misuse of statistical methods was inappropriate use of parametric methods (35/89, 39.3%). Only 14 articles (13.1%) were satisfactory in utilization of statistical methodology. Conclusion : Most of the statistical errors found in the journal were misuses of statistical methods related to basic statistics. This study suggests that researchers should be more careful when they describe and apply statistical methods and more extensive statistical refereeing system would be needed.

An Analysis of the High School 'Common Science' Contents and Textbooks (고등학교 ‘공통과학’의 교과내용 및 교과서 분석)

  • Lee, Gwang-Ho;Choi, Jong-Bum;Park, Moon-Kook;Cho, Kyu-Seong
    • Journal of the Korean earth science society
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    • v.18 no.6
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    • pp.453-463
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    • 1997
  • The contents of high school 'Common science' textbooks was analyzed qualitatively and quantitatively. Seven common science textbooks were selected and its contents, structure, inquiry, activities, appendix and its characteristics were investigated, and analyzed using the Goal Clusters of Project Synthesis and Romey's indices of text evaluation were calculated. The contents of each unit are not much different among textbooks because they are written according to the curriculum ordinance and textbook guidelines of the Ministry of Education. The textbooks was consist of $471{\sim}519$ pages. It was distribute similarly among the chapter of 'materials', 'forces', lives' and 'earth'. The chapter of 'energy' and 'environment' was treat significantly. The contents and structure of common science is a mere physical consolidation. I make an alternative plan that a topic form. Inquiry activities used in the textbooks are 11 type, however most of that is interpretation of data, experiment, survey and discussion. Ninety six percents of the experiment, belong to the 1st level, four percents of that belong to the 2nd level of the Schwab's inquiry level and there are no activities of the 3rd level. Little attention is given to Goal Cluster I, II, IV in the common science textbooks currently employed. Its content should be broadened to include all Goal Clusters of Project Synthesis. Homey's indices representing the degrees of student involvement. are $0.57{\sim}1.14$ for sentence analysis, $0.60{\sim}1.67$ for figure and diagram analysis, $0.67{\sim}1.50$ for analysis of questions at chapter ends, respectively, student activity per page investigated being $0.6{\sim}0.9$. But chapter summaries cease to repeats the conclusions of the chapter also it be rather formally and inattentively written.

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Effects of Cyanobacterial Bloom on Zooplankton Community Dynamics in Several Eutrophic Lakes (부영양호수에서 남조류 bloom이 동물플랑크톤 군집변화에 미치는 영향)

  • Kim, Bom-Chul;Choi, Eun-Mi;Hwang, Soon-Jin;Kim, Ho-Sub
    • Korean Journal of Ecology and Environment
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    • v.33 no.4 s.92
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    • pp.366-373
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    • 2000
  • Toxin production and low digestibility of cyanobacteria are known to cause low exploitability of cyanobacteria by zooplankton. In this study, we compared relative tolerance and compatibility of zooplankton taxa in eight eutrophic lakes, exposed to frequent cyanobacterial blooms, uring the summer season of 1999. Microcystis, Anabaena, Oscillatoria and Phormidium were common cyanobacteria in all lakes. with relatively lower $NO_3-N$ concentration (<0.2 mgN/l) and TN/TP ratio (<20), compared with other lakes where colonial cyanobacteria dominated. Rotifers were dominant zooplankton in most lakes, and among them, Keratella, Polyarthra and Hexathra were common. The laboratory feeding experiment showed that relative copepods that greatly decreased (90%) after 4 day when cyanobacteria were used as the food source of zooplankton, while rotifers gradually increased with the change of dominant taxa from Keratella through Pompholyx to Monostyla. These results suggest that rotifers may be capable of coexisting with cyanobacteria by exploiting them for the food source.

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Lymphangioleiomyomatosis in Korea (한국의 폐 림프관평활근종증)

  • Mo, Eun-Kyung;Jung, Man-Pyo;Yoo, Chul-Gyu;Kim, Young-Whan;Han, Sung-Koo;Im, Jung-Gi;Seo, Jeong-Wook;Lee, Seung-Sook;Shim, Young-Soo;Kim, Keun-Youl;Han, Yong-Chol
    • Tuberculosis and Respiratory Diseases
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    • v.40 no.5
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    • pp.519-531
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    • 1993
  • Background: Lymphangioleiomyomatosis(LAM) is a very rare disease occurring in women of reproductive age and leading to progressive respiratory failure despite therapy. But the natural history of this disease is uncertain and although anti-estrogenic agents have been used for more than twenty years, it's efficacy is still in debate. This study was performed to enhance understanding of this fatal disease in Korea by examining clinical, radiological, and pathologic findings of all the previously reported cases of LAM on Korea along with four new cases of LAM whom we report in this paper. Method: Out of twlve cases of LAM previously unpublished and published in domestic papers, two cases whose diagnoses were considered doubtful after review of clinical, radiological, and pathologic findings at "Asian Congress on Lymphangioleiomyomatosis" at Kyoto, Japan in feburary of 1993 were excluded from this study. Six cases which were reported previously and four new cases of LAM whom we report in this paper were analysed for the clinical, radiological, and pathologic characteristics. Results: All ten patients were women with mean age of $33{\pm}7$. The most common symptom was exertional dyspnea and most patients had history of pneumothoraces. Pulmonary function tests showed decreased diffusing capacity. on high resolution computed tomography(HRCT), all the cases had characteristic cysts. Most of the patients did not respond to hormonal therapy. Conclusion: In women of reproductive age, presenting with dyspnea who has a history of pneumothorax, LAM should always be considered as one of the diagnostic possibilities. If suspected, HRCT should be done to look for characteristic cysts and if needed, open lung biopsy should be done to confirm the diagnosis.

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A Critical Liquefaction Resistible Characteristic of Saturated Sands Based on the Cyclic Triaxial Test Under Sinusoidal Loadings (정현하중재하 진동삼축시험에 기초한 포화사질토의 액상화 한계저항특성)

  • 최재순;김수일
    • Journal of the Korean Geotechnical Society
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    • v.20 no.8
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    • pp.147-158
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    • 2004
  • Laboratory dynamic tests are carried out to assess the liquefaction potential of saturated sands in most countries. However, simple results such as the maximum cyclic shear stress and the number of cycles at initial liquefaction are used in the experimental assessment of liquefaction potential, even though various results can be obtained from the dynamic test. In addition, it seemed to be inefficient because more than three dynamic tests with different stress ratio have to be carried out to draw a liquefaction resistance experimental curve. To improve the present assessment method fur liquefaction potential, a new critical resistible characteristic far soil liquefaction is proposed and verified through conventional cyclic triaxial tests with Jumunjin sand. In the proposed method, various experimental data such as effective stress path, stress-strain relationship, and the change of excess pore water pressure can be used in the determination of cumulative plastic shear strains at every 1/4 cycle. Especially, the critical cumulative plastic shear strain to initiate liquefaction can be defined in a specific point called a phase change point in the effective stress path and it can be calculated from a hysteric curve of stress-strain relationship up to this point. Through this research, it is found that the proposed cumulative plastic shear strain can express the dissipated energy to resist dynamic loads and consider the realistic soil dynamic behavior of saturated sands reasonably. It is also found that the critical plastic shear strain can be used as a registible index of soils to represent the critical soil dynamic state, because it seems to include no effect of large deformation.