• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.18-18
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• 2019

층실사초는 경북 북부를 포함한 강원도 지역의 습기있는 음지에서 자생한다. 여러해살이풀로서 주료 사료용으로 사용되며 지피식물 등 정원소재로도 사용된다. 본 연구는 층실사초의 대량증식을 위해 가장 효과적인 파종 시기를 구명하고자 수행하였다. 종자의 최적 발아조건을 찾기 위해 배양상 온도조건을 항온조건(30, 25, 20, 15, $5^{\circ}C$)과 변온조건(15/30, 20/10, $25/15^{\circ}C$) 총 8가지 조건으로 설정하여 발아율을 매일 측정하였다. 광조건은 형광등을 이용한 명조건과 암조건을 매일 12시간씩 반복하였다. 실험결과, 항온조건에서 발아율은 $25^{\circ}C$에서 $36{\pm}6.3%$로 가장 높게 나타났고, $20^{\circ}C$ ($27{\pm}4.4%$), $30^{\circ}C$ ($24{\pm}1.6%$) 순으로 나타났으며, $15^{\circ}C$, $5^{\circ}C$에서는 발아하지 않았다. 한편, 변온조건에서의 발아율은 $25/15^{\circ}C$에서 $22{\pm}7.3%$, $15/30^{\circ}C$에서 $10{\pm}2.5%$ 발아하였고, $20/10^{\circ}C$에서는 발아하지 않았다. 따라서 층실사초 종자의 발아최적온도는 $25^{\circ}C$이고 변온보다 항온이 유리했으며, 이 이상의 온도에서는 오히려 발아율이 낮아지는 것으로 나타났다. 이러한 결과를 바탕으로 가장 효과적인 파종 시기를 추정할 때, 낮 기온 $25^{\circ}C$의 초여름에 실시하되, 밤 기온이 너무 내려가지 않도록 조절해준다면 보다 높은 발아율을 기대할 수 있을 것으로 여겨진다. 그러나 본 연구결과, 최고 발아율이 $36{\pm}6.3%$로 비교적 낮기 때문에 발아율 향상을 위한 추가적인 실험이 필요할 것이다.

• Membrane Journal
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• v.32 no.1
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• pp.43-49
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• 2022

Solid-state supercapacitors with high safety and robust mechanical properties are attracting global attention as next-generation energy storage devices. As an electrode of a supercapacitor, an economical carbon-based electrode is widely used. However, when an aqueous electrolyte is introduced, the charge transfer resistance increases because the interfacial contact between the hydrophobic electrode surface and aqueous electrolyte is not good. In this regard, we propose a method to obtain higher electrochemical performance based on improved interfacial properties by treating the electrode surface with oxygen plasma. The surface hydrophilization induced by the enriched oxygen functionalities was confirmed by the contact angle measurement. As a result, the degree of hydrophilization was easily adjusted by controlling the power and duration of the oxygen plasma treatment. As the electrolyte of the supercapacitor, PVA/H₃PO₄, which is a typical solid-state aqueous electrolyte, was used. Free-standing membranes of PVA/H₃PO₄ electrolyte were prepared and then pressed onto the electrode. The optimal condition was to perform oxygen plasma treatment for 5 seconds with a low power of 15 W, and the energy density of the supercapacitor increased by about 8%.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.8
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• pp.870-876
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• 2005

The multiple regression models which have two factors(population and commercial area) have been used to forecast the water demand in the future. But, the coefficient of population had a negative value because proper regional classification wasn't performed, and it is not reasonable because the population must be a positive factor. So, the regional classification was performed by principal component and cluster analysis to solve the problem. 6 regional characters were transformed into 4 principal components, and the areas were divided into two groups according to cluster analysis which had 4 principal components. The new regression models were made by each group, and the problem was solved. And, the future water demands were estimated by three scenarios(Active, moderate, and passive one). The increase of water demand ore $89.034\;m^3/day$ in active plat $49,077\;m^3/day$ in moderate plan, and $19,996\;m^3/day$ in passive plan. The water supply ability as scenarios is enough in water treatment plant, however, 2 reservoirs among 4 reservoirs don't have enough retention time in all scenarios.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1306-1313
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• 2011

A liquid fertilizer treated with slurry composting and biofiltration (SCB) process has been applied increasingly on agricultural field but the effects on the soil properties and crop production has not been throughly evaluated. This study was conducted to investigate the effect of the SCB application on soil chemical properties and the growth of radish and corn. SCB liquid fertilizer as a basal fertilization was treated with five levels based on $6kg\;10a^{-1}$ for radish and $10kg\;10a^{-1}$ for corn. The experimental design was the completely randomized block design with five levels and three replicates. Electrical conductivity (EC), $NO_3$-N, Exch. K and Exch. Na increased depending on the treatment levels of SCB. There were no changes in soil organic matter, Avail. $P_2O_5$, Exch. Ca and Exch. Mg. EC, $NO_3$-N and Exch. Na content decreased as precipitation increased. Especially, they decreased up to the initial condition before the treatment after the heavy rainy season in 2008. Although Exch. K decreased at the rainy season, they remained relatively higher content after the experiment on August, 2008. Fresh weight and the amount of N uptake of radish increased due to the levels of SCB, but corn did not present any significant increase. It is recommended that we need to decide the proper amount of SCB as well as the application method on the field to increase the productivity and decrease environmental stress. Additional experiments also need to clarify the effect of the trace element and heavy metal accumulations due to long term application of SCB.

• Journal of Aquaculture
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• v.13 no.4
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• pp.339-351
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• 2000

Optimal environmental conditions, that sustained fastest growth, lowest mortality and abnormality of the scallop Patinopecten yessoensis, were identified from field experiments undertaken at Chumunjin during 1991-1998. Temperature within the water column 10~30 m depth ranged between 5 and 23$^{\circ}C$; high temperature and daily fluctuation resulted in growth retardation and heavy mortality of the scallop. Optimal salinity range was between 31.5 and 34.5%0 and water transparency 6.0 and 18.1 m, which was significantly affected by phytoplankton density. Chlorophyll concentration ranged between 0.04 and 3.51 f.lgfL. Low temperature and high chlorophyll concentration appear to support faster growth of the scallop. Optimal periods of transplantation for intermediate culture were between mid July and early November: cultured under high density during July-August as a first step and under low density during mid September through early November as a second step. Optimal stocking density in square net cage (<35${\times}$35 em) for intermediate culture was 30-40 individuals per cage for main culture using lantern net and 80 -100 individuals of the size of 1.5 ~ 3.0 em shell height per cage for sowing culture. During the intermediate culture, the highest growth was realized, when the cage was held at water depth between 10 and 15 m. Water depth below 25 m, however, was best to avoid mass mortality during the periods of abnormally high water temperature and high variation of water temperature. The daily growth rate during the intermediate culture was between 0.019~0.381 mm; low in January and February but high in March and April. It is suggested that the main culture is commenced before June under low stocking density to avoid the possibility of mass mortality during summer by high water temperature.

• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.314-318
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• 2000

To compare heavy metal phytoavailability in paddy soils near five abandoned mining areas, 4 different soil extractants such as 0.1M-HCl, $0.1M-HNO_3$, 0.05M-EDTA, and 0.005M-DTPA were used. Total acid digestion method $(H_2SO_4:HClO_4:HNO_3)$ was also employed to analyze heavy metal content in 30 paddy soils and brown rice. The rates of extracted heavy metal to total content were in the range of $12.1{\sim}39.1%$ for Cd, $20.5{\sim}45.5%$ for Cu, $10.6{\sim}30.7%$ for Pb, and $6.7{\sim}13.0%$ for Zn. 0.1M-HCl and $0.1M-HNO_3$ extractable both Cu and Pb were relatively less extracted at the high soil pH and extractable calcium site(Mine D) whereas 0.05M-EDTA and 0.005M-DTPA extractable Pb were strongly extracted at the same soils. In case of Cd, Cu, and Zn in soil, 4 types of extractable heavy metals and total content were highly correlated with each other. However, there were positive correlations between 0.1 M-HCl and $0.1M-HNO_3$ extractable Pb as well as between 0.05M-EDTA and 0.005M-DTPA extractable Pb, which were relatively similar extractants in chemical properties. The rates of heavy metals in brown rice to total contents in soils were in the order Zn>Cd>Cu>Pb. Specially, the rate of Cd, Pb, and Zn were lower at the highest level of soil pH and Ex. Ca. Both Cd and Zn in brown rice were positively correlated with those of all soil extractants. It was estimated that the solubility following to the plant uptake of Cd and Zn were higher than those of Cu and Pb considering relationships between all kinds of heavy metal contents in soil and those in brown rice.

• Journal of Yeungnam Medical Science
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• v.15 no.2
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• pp.325-340
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• 1998

A cross-sectional study was conducted to evaluate the relationship between sick building syndrome(SBS) and the environmental factors affecting SBS on 130 underground workers and 60 controls. The study consisted of 1) a review of environmental condition 2) measurement of temperature, $O_2$, $CO_2$, CO, and formaldehyde and 3) a questionnaire survey of symptom prevalence and perception of environmental conditions using indoor Air Quality questionnaire recommended by National Institute for Occupational Safety and Health. Bronchitis and dust allergy were more prevalent in underground workers significantly(p < 0.05). Among the 18 symptoms related to the indoor air pollution, the experience rate of dry, itching or irritated eyes, sore or dry throat, chest tightness, tired or strained eyes and dry or itchy skin symptom was significantly different between the underground workers and controls. The diagnostic criteria of SBS was defined as at least 1 symptom is experienced 1-3 times a week during the last 1 month among 18 indoor air pollution related symptoms which can be relieved by moving out of the underground. Applying the criteria, the mean symptom score was significant higher in underground workers than controls significantly (p < 0.05). These resalts indicated that underground workers are under inappropriate ergonomic and physical condition and inadequate ventilation. Their experience rate of symptoms related to indoor air pollution and prevalence of SBS was significantly higher than controls. To reduce the prevalence of SBS of underground workers, the surveillance system of indoor air quality, restriction of using fuel in underground and legislative regulations for the environment are needed to establish a better indoor air quality. Early detection, treatment and prevention of SBS through medical attention is also needed.

• Korean Journal of Weed Science
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• v.13 no.2
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• pp.104-113
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• 1993

The experiment was conducted in 1992 to find out the approach to the development of prediction model of weed population in paddy fields. The weed seeds of 88% over were separated from the soil by using $K_2CO_3$ 50% solution with specific gravity 1.34. The weed seeds which were floated on the solution due to the difference of specific gravity between soil particles and the seeds were effectively withdrawn by using a vaccum pump attached with an aspirator. The seeds withdrawn together with solution were taken by filtering with a nylon net of $0.31{\times}0.16mm$ mesh. The pressing method was more efficient and practical for the viability test of weed seeds separated from the soil compared with the germination test and the TTC test. For the prediction of weed population by the number of weed seedlings emerged at the sampled soil, the sampling method of 0-10cm deep at 5-6 sites per field was applicable. At the prediction method by the number of seedlings emerged, the smaller the seed sizes, the lower the prediction coefficients of weed species. It was considered that the prediction method by the number of seedlings emerged was more practical than the prediction method by the number of seeds separated from sampled soil, in relation to similarities to weed population, time and expenses required for examining, technical difficulties and applicability of weed species.

• Korean Journal of Weed Science
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• v.14 no.3
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• pp.212-222
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• 1994

Thiobencarb retarded the growth of new leaves in only barnyardgrass under dry condition while under water condition the shoot growth of broadcast rice, and both shoot and root growth of barnyardgrass was considerably inhibited. Root elongation of rice and barnyardgrass was severely inhibited only under water condition, while that of transplanted rice was slightly inhibited. Inhibition of shoot and root growth in broadcast, drilled rice and barnyardgrass under water condition was much higher than that under dry condition, whereas the inhibition was less in transplanted rice than direct seeded rice. Microscopically, thiobencarb severely inhibited shoot growth and development of barnyardgrass by inducing tubular-like leaves. The cells of the shoot apices of treated barnyardgrass seedling under dry condition was vacuolated and irregularly arranged. Under water condition, leaf primordia of broadcast rice was constricted, barnyardgrass showed tubular-like leaves, inhibited apices elongation and vacuolated cells(visually lack cytoplasm).

• Tuberculosis and Respiratory Diseases
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• v.58 no.6
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• pp.576-581
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• 2005

Background : Thoracic actinomycosis is a relatively uncommon anaerobic infection caused by Actinomyces israelii. There have been only a few case reports of endobronchial actinomycosis. The aim of this study was to evaluate the clinical manifestation and treatment of endobronchial actinomycosis. Material and Methods : Seven patients with endobronchial actinomycosis, who were diagnosed in the past 10 years, were retrospectively reviewed. Results : Cough and sputum were the most common symptoms. The chest radiograph and computed tomography showed necrotic consolidation (n=3), atelectasis (n=2), mass (n=1) and an endobronchial nodule (n=1). Proximal broncholithiasis was observed in five patients. All cases were initially suspected to have either lung cancer or tuberculosis. In these patients, the median duration of intravenous antibiotics was 3 days (range 0-12 days) and the median duration of oral antibiotics was 147 days (range 20-412 days). Two patients received oral antibiotic therapy only. There was no clinical evidence of a recurrence. Conclusion : Endobronchial actinomycosis frequently manifests as a proximal obstructive calcified endobronchial nodule that is associated with distal post-obstructive pneumonia. The possibility of endobronchial actinomycosis is suggested when findings of broncholithiasis are present at chest CT. The traditional recommendation of 2-6 weeks of intravenous antibiotics and 6-12 months of oral antibiotic therapy are not necessarily essential in all cases of endobronchial actinomycosis.