• 한국물환경학회지
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• 제21권3호
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• pp.230-235
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• 2005

The main purpose of the flocculation process is to make flocs bigger to be removed easily in the following processes. The flow pattern and mixing intensity have a great influence on flocculation. In this study, the flow pattern was examined by a hydraulic tracer-test, where 3 water treatment plants having $800,000m^3/d$, $44,000m^3/d$ and $40,000m^3/d$ were employed. Also, the settling test was conducted to find out the relationship between the mixing intensity and the settling ability of flocs. The hydraulic tracer-test was conducted for the various flocculation processes that have different structures of flocculation basins. In the result, the retention time distribution (RTD) curves for the flocculation processes were quite different. In case of the inappropriate structure of the flocculation basin, the flow is not even so that the floc does not grow enough. To find out the relationship between mixing intensity and settleability of flocs, G-values were calculated and the settling test was conducted for two flocculation basins which have the same conditions except the G-value. For the flocculation basin with uneven G-value, the floc settleability was revealed poor. On the other hand, the flocculation basin with even G-value, the settleability was better than the previous one. From these experimental results, it is confirmed that the flow pattern is closely related to the structure of the flocculation basin and the settleability is affected by mixing intensity. Therefore the flow pattern and the strength of the mixing intensity should be examined sufficiently to design and operate flocculation basin.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2020년도 추계국제학술대회
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• pp.61-61
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• 2020

This experiment was carried out using artificial bed soil and LED in the plastic film house(irradiation time: 07:00-17:00/day). Seedlings(n=63 per 3.3 m²) of ginseng was planted on May 17, 2018. LED was combined with red and blue light in a 3:1 ratio and irradiated with different light intensity(40-160 µmol/m²/s). Average air temperature from April to September according to the light intensity test was 20.4℃-20.9℃. Average artificial bed soil temperature was 20.1℃-21.7℃. The test area where fluorescent lamp was irradiated tended to be somewhat lower than the LED irradiation area. The chemical properties of the test soil was as follows. pH levels was 6.6-6.7, EC levels 0.9-1.3 dS/m and OM levels 30.6-32.0%. The available P₂O₅ contents was 73.3-302.3 mg/kg. Exchangeable cations K and Ca contents were higher than the allowable ranges and mg content was high in the fluorescent lamp treatment. The photometric characteristics of LED light intensity are as follows. The greater the light intensity, the higher the PPFD(Photosynthetic Photon Flux Density) value, illuminance and solar irradiation. Fluorescent lamp treatment had high illuminance value, but PPFD and solar irradiation were lower than LED intensity 40 µmol/m²/s treatment. The photosynthetic rate increased(2.0-3.8 µmolCO²/m²/s) as the amount of light intensity increased, peaking at 120 µmol/m²/s, and then decreasing. The SPAD (chlorophyll content) value decreased as the amount of light intensity increased, and was the highest at 36.1 in fluorescent lamp treatment. Ginseng germination started on April 5 and took 14-17 days to germinate. The overall germination rate was 68.8-73.6%. The growth of aerial parts(plant height etc.) were generally excellent in the treatment of light intensity of 120-160 µmol/m²/s. The plant height was 41.9 cm, stem length was 24.1 cm, leaf length was 9.8 cm and stem diameter was 5.6 mm. The growth of underground part (root length etc.) was the best in the treatment with 120 µmol/m²/s of light intensity. Due to the root length was long(24.8 cm) and diameter of taproot was thick(18.7 mm), the fresh root weight was the heaviest at 24.8 g. There were no disease incidence such as Alternaria blight, Gray mold and Anthracnose. Disease of Damping-off caused by Rhizoctonia solani occurred 0.6-1.5% and incidence ratio of rusty root ginseng was 30.8-62.3%. It is believed that the reason for the high incidence of rusty root ginseng is that the amount of field moisture capacity of artificial bed soil is larger than the soil. Leaf discoloration rate was 13.7-32.3%.

• 기술혁신연구
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• 제20권1호
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• pp.45-73
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• 2012

본 연구는 2000년부터 2010년까지 한국거래소의 유가증권시장과 코스닥시장에 상장된 기업을 대상으로 기업의 재무적 특성변수가 R&D 투자와 기업가치간의 관계에 미치는 영향을 실증분석 하였으며, 주요한 분석결과는 다음과 같다. 기업규모는 R&D 투자와 기업가치간의 관계에 양(+)의 영향을 미친다. 이는 R&D 투자는 중소기업보다 대기업의 기업가치에 더 큰 영향을 미침을 의미한다. 기업의 잉여현금흐름은 R&D 투자와 기업가치간의 관계에 음(-)의 영향을 미친다. 이는 잉여현금흐름이 높은 기업은 순현재가치(NPV)가 음(-)인 투자안에 여유자금을 투자할 과잉투자위험이 존재한다는 Jensen(1986)의 이론을 지지한다. 기업의 시장점유율은 R&D 투자와 기업가치간의 관계에 양(+)의 영향을 미친다. 시장점유율과 R&D 투자는 상호보완적으로 작용하므로, 시장점유율이 높은 기업은 R&D 투자도 증가하여 시장가치가 증가한다. 기업의 외부금융 의존도는 R&D 투자와 기업가치간의 관계에 음(-)의 영향을 미친다. R&D 투자는 비대칭정보로 인한 역선택비용을 크게 발생시키므로, 외부금융에 의존하기보다 내부금융을 사용하는 것이 더 유리할 수 있다. 그리고 기업의 노동집약도와 자본집약도는 각각 R&D 투자와 기업가치간의 관계에 음(-)의 영향을 미치는데, 전자는 노동집약도가 높은 기업일수록 종업원들 간에 초과수익률이 희석될 가능성이 높기 때문이고, 후자는 자본집약도가 높은 기업일수록 재무적 제약에 직면할 가능성이 높기 때문이다. 결론적으로, 본 연구에서 설정한 기업의 재무적 특성변수 중에서, 기업규모와 시장점유율은 R&D 투자와 기업가치간의 관계에 양(+)의 영향을 미치지만, 잉여현금흐름, 외부금융의존도, 노동집약도 및 자본집약도는 음(-)의 영향을 미친다. 따라서 기업 경영자들은 이러한 재무적 특성변수들이 R&D 투자와 기업가치간의 관계에 미치는 영향을 올바르게 이해하여 R&D 투자를 결정함으로써 기업가치를 증가시킬 수 있다.

• 대한물리의학회지
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• 제9권1호
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• pp.45-53
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• 2014

PURPOSE: In this study, we tried to find out what kind of exercise was more effective in sleep disorder by comparing melatonin in blood after applying low intensity with high intensity exercise to sleep disordered rats induced by experiment. METHODS: We used male Sprague-Dawley rats which were 8weeks old and weighted 300g. They were supplied with water and food without any restriction. We kept the room temperature at $25^{\circ}C$ and controld the length of day and night in 12 hours blocks, respectively. We divided the rats 60 into 2 groups. To one group we applied low intensity exercise, and to the other we applied high intensity exercise for 15minutes per day over a period of 4 weeks. We extracted the blood from abdominal aorta before, after exercise, moved into EDTA tube, performed centrifugation. We decanted the serum $200{\mu}l$ from the blood into microcentrifuge tube by samples and moved into polypropylene culture tubes with micro pipette. We split enzyme solution $50{\mu}l$ into the tubes with melatonin direct kits and make them react at $37^{\circ}C$ for 2 hours. We split assay buffer $50{\mu}l$ into each tube and mixed melatonin tracer $50{\mu}l$ and melatonin antiserum $50{\mu}l$, respectively. After we made them react in room temperature, we decanted the superficial layer with a centrifuge and measured the activity for 1 minute by competitive method with ${\gamma}$-counter equipment. We draw a standard curve through logit-log graph with CPM(counts per minute) and counted the melatonin by B/B0. We conducted independent t-test to examine the homogeneous of melatonin value of before low-intensity and high-intensity exercise. We performed paired t-test to compare before and after low-intensity and high-intensity exercise, respectively. We carried out independent t-test to compare melatonin value after low-intensity and high-intensity exercise. Significance level was .05. RESULTS: The results were as follows; firstly melatonin was more increased in the group who was exposed to high intensity exercise when we compared before to after high and low intensity exercise, respectively. Secondly, high intensity exercise was more effective than low intensity exercise when we compared the two. CONCLUSION: In conclusion, secretion of melatonin which is the material of sleep improvement could be promoted by high intensity exercise. Low intensity exercise acted as a stress rather than improving sleep and had a negative effect on the secretion of melatonin because the melatonin was affected by stress.

• 한국콘텐츠학회논문지
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• 제11권9호
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• pp.26-44
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• 2011

본 연구는 기지국 설치 건물의 층별 전자파 강도가 인체에 유해한지, 그리고 예측 가능한지를 조사하기 위해 수행되었다. 조사는 산란체가 많은 기지국과 산란체가 적은 기지국을 선별하여 실험을 하였다. 실험은 국제 규격과 국내 TTA 표준을 모두 충족시키기 위해, 기지국이 설치된 건물의 층별로 세가지 높이(1.1m,1.5m,1.7m)를 기준으로 하여 각 높이에서 3개의 위치에서 전자파 강도의 실효값(rms)이 측정되었다. 9개의 위치에서 측정된 주파수별 실효값(rms)의 Max가 전자파 인체 보호 기준대비 최대 48.12%(옥상 측정값)로 주파수별로 인체보호 기준을 만족함을 확인하였다. 그리고 산출된 주파수 별 노출지수 합도 최대 0.1445로 기준 1대비 최대 7배 이상 낮은 수준임을 확인하였다. 기지국별, 층별 조건에서는 868MHz, 2.14GHz의 전자파 강도 모두 P>0.005로 유의하였으며, R-Sq(조정)값이 50% 이상값을 보여서 회귀 방정식이 데이터의 정보를 충분히 흡수하고 있다는 것을 확인하였다. 그러나 기지국 데이터 통합, 층별 데이터 통합 조건에서는 868MHz, 2.14GHz의 전자파 강도 모두 P>0.05 이지만, 868MHz 전자파 강도의 R-Sq(조정)값이 50%이하 값(34.15%)을 보여서, 868MHz 전자파 강도는 기지국이 설치된 환경에 많은 영향을 받는 것을 확인 할 수 있었다. 2.14GHz의 전자파 강도는 R-Sq(조정)값이 50% 이상(51.8%)를 보여서 2.14GHz의 전자파 강도의 회귀방정의 모형은 적합하였으며, 기지국이 설치된 건물의 주변 환경에 크게 영향을 받지 않고, 기지국 설치 건물의 층별 전자파 강도를 회귀 방정식으로 예측 할 수 있었다.

• 대한방사선기술학회지:방사선기술과학
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• 제42권6호
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• pp.441-446
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• 2019

The purpose of this paper is to recognize the usefulness of the Phantom produced with 3D printing technology by reproducing the original phantom with 3D printing technology. Using CT, we obtained information from the original phantom. The acquired file was printed by the SLA method of ABS materials. For inspection, SPECT/CT was used to obtain images. We filled the both Phantom with a solution mixed with ^99mTcO4 1 mCi in 1 liter of water and acq uired images in accordance with the standard protocol. Using Image J, the SNR for each slice of the image was obtained. As a reference images, AC images were used. For the analysis of acquired images, ROI was set in the White mater and Gray mater sections of each image, and the average Intensity Value within the ROI were compared. According to the results of this study, 3D printed phantom's SNR is about 0.1 higher than the conventional phantom. And the ratio of Intensity Value was shown in the original 1 : 3.4, and the printed phantom was shown to be 1 : 3.2. Therefore, if Calibration Value is applied, It is assumed that it can be used as an alternative to the original.

• 유통과학연구
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• 제13권6호
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• pp.35-44
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• 2015

Purpose - To accelerate economic cooperation, this study investigates trade structures of Korea and the United States and identifies trade discrepancies. Such discoveries can lead to increases in trade volume by improving policies, eventually uncovering ways for trade expansion. Research design, data, and methodology - The Index of trade intensity, from trade intensity theory, is used to analyze the trade decision factors. Even though specific factors should materialize in the analysis, realistically, concrete explanations are difficult as there are so many unsolved factors and diversifications. Results - First, the Index of A value/ B value positions Korean against the United States in terms of market share and Korea against world market share, which thereby reveals comparative market intensity. Second, Korea is taking comparative advantage of export specialization. Third, real comparative advantage indices are considerably improved since early 2000. Conclusions - This study uses quantitative measurements and trade intensity theory and trade specialization to come up with a comparative advantage index to see how inter-trade relations between Korea and the United States have changed over the past 10 years.

• 유통과학연구
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• 제11권11호
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• pp.33-40
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• 2013

Purpose - This study, in seeking to understand the trade structure of both Korea and China, aims to strengthen Korea-China economic cooperation; it examines trade impediments by analyzing the problems affecting trade and addressing these problems, thereby discovering ways to expand trade between these countries. Research Design, Data, and Methodology - The index of trade intensity developed by the trade intensity theory (Kruger, 1997) is used to analyze the trade decision factors of both countries. Although specific factors should have materialized from the analysis of trade decision factors, determining concrete explanations is difficult in reality, as there are many unsolved and diverse factors. Results - First, the index of A value/B value is the index of Korean versus Chinese market share/Korean versus world market share, which is a measure of comparative market intensity. Second, Korea has a comparative advantage in export specialization and, conversely, China has a comparative advantage in import specialization. Third, compared to 2000, the revealed comparative advantage (RCA) indexes are considerably improved. Conclusions - This study used quantitative measurement for analysis, applying trade intensity theory, trade specialization, and RCA indexes to gauge how inter-trade relations have changed between Korea and China during the past 10 years (2000, 2005, and 2012).

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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• pp.3407-3412
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• 2015

Background: The aim of this study was to evaluate and compare the accuracy of diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC) value, and time-intensity curve (TIC) type analysis derived from dynamic contrast-enhanced MR imaging (DCE-MRI) in differentiating benign from malignant adnexal masses. Materials and Methods: 47 patients with 56 adnexal masses (27 malignant and 29 benign) underwent DWI and DCE-MRI examinations, prior to surgery. DWI signal intensity, mean ADC value, and TIC type were determined for all the masses. Results: High signal intensity on DWI and type 3 TIC were helpful in differentiating benign from malignant adnexal masses (p<0.001). The mean ADC value was significantly lower in malignant adnexal masses (p<0.001). An ADC value< $1.20{\times}10^{-3}mm^2/s$ may be the optimal cutoff for differentiating between benign and malignant tumors. The negative predictive value for low signal intensity on DWI, and type 1 TIC were 100%. The pairwise comparison among the receiver operating characteristic (ROC) curves showed that the area under the curve (AUC) of TIC was significantly larger than the AUCs of DWI and ADC (p<0.001 for comparison of TIC and DWI, p<0.02 for comparison of TIC and ADC value). Conclusions: DWI, ADC value and TIC type derived from DCE-MRI are all sensitive and relatively specific methods for differentiating benign from malignant adnexal masses. By comparing these functional MR techniques, TIC was found to be more accurate than DWI and ADC.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권1호
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• pp.31-38
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• 2002

We measured a 3-dimensional images of the light emitted from plasma display panel(PDP) by using newly proposed scanned point detecting system. In the panel without phosphor, as we scan from the rear glass to the front glass, the detected light intensity increases and the light intensity detected in the inside edge of the ITO electrodes shows the stronger intensity than others. The light intensity detected between the barrier ribs shows the largest value of brightness. Also, as the sustain voltage increases, the detected light intensity increases. In the panel with phosphor, the intensity of light detected at barrier rib shows the stronger light intensity than rear plate. Therefore, the phosphor of barrier rib is very important. From these results the 3-dimensional measurement is necessary to understand exactly the discharge phenomenon in the PDP cell.