• Environmental Engineering Research
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• v.23 no.2
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• pp.164-174
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• 2018

Corrosion of copper alloys (copper, bronze and brass) in soil was evaluated at ambient temperature using various methods such as electrochemical impedance spectroscopy (EIS), polarization curves and Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy microanalysis measurements. Three equivalent circuits were separately used to interpret the obtained impedance spectra. The EIS measurements indicated that the polarization resistance of all electrodes increases with increasing the immersion time. SEM showed a presence of three layers of corrosion products with various composition and morphology covering each electrode. In addition, it was found that at 20% of moisture content the $R_p$ values and the current density of all electrodes in the studied soil give the following order: copper > bronze > brass. Good consistency between the data obtained from EIS and PP measurements was observed.

• Korean journal of applied entomology
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• v.10 no.1
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• pp.59-62
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• 1971

The highest fresh weight of Agaricus bisporus was obtained at pH 7.5 of casing soil. Above or below this pH level, the yields were significantly reduced. Stimulatory effect of calcium on the mycelial growth depended upon pH of casing soil, In neutral or slightly alkaline soil, the stimulatory effect was increased. The effects of supplementing calcium carbonate or hydrated lime to casing soil were assumed not only the influence of pH of casing soil, but also stimulatory effect of calcium ion on mycelial growth of A. bisporus.

• Applied Biological Chemistry
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• v.14 no.3
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• pp.221-227
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• 1971

Potential grain yield of rice plant was calculated from potential grain yield of each leaf for two lines of IR 667 and two commercial varieties (Jinhung and Paldal). According to the percentage contribution of each leaf the pattern of potential grain yield of IR 667 lines could be grouped into the upper leaf-dependent type indicating fast senescence while that of commercial varieties could be grouped into the lower leaf-dependent type indicating shade resistance. The comparisons between potential grain yields and apparent grain yields indicate that the commercial varieties having a comparably unfavorable plant type thus remained much behind the potential yield. The significance of potential grain yield was discussed in relation to nutrio-physiology and breeding. Methods for potential yield determination were also discussed.

• Korean journal of applied entomology
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• v.9 no.1
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• pp.49-51
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• 1970

1. Claviceps species or Graminaceae were investigated from Kyonggi-Do Korea including Kwang-neung, Anseung, Pyongtack, Chingpyong Yichun and Suwon from June to November, 1969. 2. Sclerotia of Claviceps species were collected from 16 species of Graminaceae consisted of 11 genera. 3. New hosts of Claviceps species including 15 species in 10 genera were reported in Korea, 4. Claviceps pucilla Ces. on Themeda riandra FORSK. var. japonica M. was recorded in addition to Claviceps purpurea (Fr.) Tul. 5. Claviceps Purpurea (FR.) Tul. on Miscanthus Sinensis ANDERS occured at 449m above sea level near Suwon.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.419-430
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• 2021

Remote sensing techniques using drone-based multispectral image were studied for fast and two-dimensional monitoring of algal blooms in the river. Drone is anticipated to be useful for algal bloom monitoring because of easy access to the field, high spatial resolution, and lowering atmospheric light scattering. In addition, application of multispectral sensors could make image processing and analysis procedures simple, fast, and standardized. Spectral indices derived from the active spectrum of photosynthetic pigments in terrestrial plants and phytoplankton were tested for estimating chlorophyll-a concentrations (Chl-a conc.) from drone-based multispectral image. Spectral indices containing the red-edge band showed high relationships with Chl-a conc. and especially, 3-band model (3BM) and normalized difference chlorophyll index (NDCI) were performed well (R²=0.86, RMSE=7.5). NDCI uses just two spectral bands, red and red-edge, and provides normalized values, so that data processing becomes simple and rapid. The 3BM which was tuned for accurate prediction of Chl-a conc. in productive water bodies adopts originally two spectral bands in the red-edge range, 720 and 760 nm, but here, the near-infrared band replaced the longer red-edge band because the multispectral sensor in this study had only one shorter red-edge band. This index is expected to predict more accurately Chl-a conc. using the sensor specialized with the red-edge range.

• Korean journal of applied entomology
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• v.12 no.1
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• pp.33-39
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• 1973

The yield of rice is increased to amounts of fertilizer applied in paddy field but excessive application of fertilizer stimulates outbreaks of disease and insect pest. If, therefore, diseases and pests stimulated by excessive application of fertilizer would be effectively controlled, increaseed yield of rice would be possible. This experiment was conducted to determine the fertilizer application rate that would produce maximum yields when diseases and pests are controlled. 1. The fertilizer application rates and the incidence of leaf and apanicle blast were positively correlated at the $1\%$ level. 2, Without disease and pest control the maximum yield of hulled rice was 347-378kg/10a, which occurred at nitorgen application levels of 8.0-8.5 kg/10a. with effective control of diseases and pests the maximum yield of hulled was 453-462 kg/10a, which occurred at nitrogen application levels of 18.5-19.0 kg/10a. Yield increase at appropriate nitrogen levels by disease and pest control resulted in more than 100 kg/10a. 3. There was no significant yield difference between the NPK experimental plots with fixed PK levels and with varying PK levels. 4. The maximum effect of disease and pest .control as expressed biy yield index of hulled rice was $65\%$, the minimum effect was $30\%$, the average effects were $42-45\%$.

• Journal of dental hygiene science
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• v.8 no.1
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• pp.35-42
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• 2008

This survey was compared and analyzed about the primary factor that dental office's working environment effect on physical subjective symptom and based on self-filling survey, 656 dental hygienists on July through August 2006, and analyzed using descriptive statics, ANOVA and Multiple Regression Analysis. The result of satisfaction degree of hospital working environment was pretty low about office air condition. Most people have complained that office's air quality makes it difficult to their work and mentioned that they were sore and dull all over the back, shoulder, and neck. The odor is major factor to be satisfied with office environment. Proper ventilates the way open the window more often was essential to maintain fresh indoor air quality and keep the extraction materials by separator and sealing tightly for remove the odor. Other factors were temperature, lighting fixture, ventilation facilities, and freshness of air. Dental hygienist was unsatisfied with hospital air condition and this polluted air condition was the cause of physical subjective symptom in work place. Furthermore, this research would be applied for improvement of working environment by decreasing of indoor air pollution.

• Korean Journal of Environment and Ecology
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• v.18 no.4
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• pp.446-455
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• 2004

This study has been conducted as a basic research for developing efficient ways of managing Korean National Parks by finding differences via the comparison of present management systems of national parks in Korea and Japan. The survey was conducted through telephone interviews and direct interviews with staffs of related organizations as well as related literature study. In result, it is found that Japanese national parks have a numerical standard of minimum area, with less staff than Korea, and larger designated areas are being managed. Management organizations of both countries are divided as main and commission. In Korea, 6 staff in Natural Resources Division under Ministry of Environment are managing main organization, and in Japan, 53 staff of 3 divisions(National Park Division, Natural Environment Management Division, General Affairs Division) are taking charge of it. Moreover, General Affairs Division, dividing whole country into 11 blocks, manages 11 units of natural preservation offices, 12 branch offices, and 67 units of nature preservation management offices. In case of commission, Foundation of Natural Park Beautification & Management in Japan has a headquarter and 20 branch offices with 54 staff who are only doing site management, while in Korea, the National Parks Management Corporation has a headquarter and 25 offices with 748 staff carrying out main office jobs and site management side by side. From the differences in both countries, we could suggest efficient measures for our national park management as follows: \circled1 introduction of numerical value as criteria for national park designation, \circled2 review of use zone, \circled3 division of the national park management office into site office and regional office, with dividing works and re-posting staff, \circled4 enlargement of park management division in Department of Environment, \circled5 National Park authority becomes a national public servant

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2011.04a
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• pp.142-144
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• 2011

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.86-93
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• 2016

Performance tests of a 75-tonf liquid rocket engine turbopump were conducted. The performance of sub-components - two pumps and a turbine - and their power matching were measured and examined firstly near the design speed under the LN2 and kerosene environment. In the real propellant - LOX and kerosene - environment tests, design and off-design performance of turbopump were fully verified in regime of the rocket engine operation. During the off-design performance tests, turbopump running time was set longer than the engine operating time to verify the pump operability and set the pump inlet pressure close to design NPSHr to investigate pump suction capability in parallel. It has been found that developed-turbopump satisfied all of the engine required performances.