• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.25-30
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• 2010

Purpose: This study was conducted to estimate the changes of corrected diopter and corrected visual acuity with the change in vertex distance. Also we aimed to provide basic data for refraction test. Methods: Using the trial lens, we measured the corrected diopter and corrected visual acuity after performing binocular balance test. We measured the changes of corrected diopter and corrected visual acuity in change of vertex distance. We analyzed statistical significance and relations between vertex distance and corrected diopter and corrected visual acuity. Results: There was no difference in corrected diopter with the change of vertex distance within -1.00D, but the corrected diopter increased with it over - 1.25D. In particular, the change of diopter was largest when the vertex distance increased 15 mm. At over 11.00D, there was large changes of diopter with the changes of vertex distance at 5 mm, 10 mm and 15 mm. On correlation analysis between the vertex distance and the corrected diopter, there was strong correlation (r=0.999 at 5 mm increase of vertex distance, r=0.982 at 10 mm increase and r=0.957 at 15 mm increase) and also there was significant (p<0.01). At the change of visual acuity in increased of vertex distance, the range of a decrease in visual acuity was large when the changes of vertex distance was largest. On correlation analysis between the vertex distance and the corrected visual acuity, there was strong correlation (r=0.969 at 5 mm increase of vertex distance, r=0.985 at 10 mm increase and r=0.994 at 15 mm increase) and also there was significant (p<0.01). Conclusions: The vertex distance was very important at the refraction test and at wearing spectacle. On correlation analysis between the vertex distance and the corrected diopter, and the corrected visual acuity, there was strong correlation and statistically significant. Therefore, the vertex distance should be kept at the refraction using trial lens, and the best fitting was made not to slipping forward, and so we suggested regular refitting of spectacle and the managing method of spectacle were educated to the spectacle wearers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.529-536
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• 2011

In this study, we confirmed that the SWRO(Sea Water Reverse Osmosis) production water has more hard corrosiveness than the tap water by fundamental experiment. According to the result, the target of this study was aimed at developing maintenance and anti-corrosion method. In the early stages of the research, batch tests using mild steel coupons and electrochemical experiments were applied to compare the corrosiveness between SWRO production water and the tap water. After then, two corrosion control methods for SWRO production water were applied. Liquid lime($Ca(OH)_2$) and Carbon Dioxide($CO_2$) were inserted and compared with the combination of liquid lime with phosphate corrosion inhibitor and carbon dioxide. The water qualities were evaluated through LSI(Langelier Saturation Index) and proper injection ratio was deduced by the result. Since then, simulated loop system test were performed to evaluate anti-corrosion effect depending on corrosion inhibitors. Subsequently, carbon steel pipes equipped at the loop system were detached for SEM, EDX and XRD analysis to acquire quantitative and qualitative data of the major corrosion products inside the pipes. In conclusion, the controled groups with anti-corrosion techniques applied were effective by appearing 97.4% and 90.9% of improvements in both case of liquid lime and the liquid lime with a phosphate corrosion Inhibitor. furthermore, major components of scale were iron oxides, on the other hand, protective effect of film formation by calcium carbonate($CaCO_3$) could be confirmed.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.6
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• pp.715-721
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• 2007

Residual calcium concentration is high, in general, at the effluent of the fluoride removal process in the electronics industry manufacturing semiconductor and LCD. To increase the stability of the membrane process incorporated for reuse of wastewater, the residual calcium is required to be pre-removed. Hyperkinetic Vortex Crystallization(HVC) process was installed in the electronics industry manufecturing semi conductor as a pilot scale for accelerating calcification of calcium ion. Compared to the conventional soda ash method, the 31% higher calcium removal efficiency was achieved when HVC was applied at the same sodium carbonate dosage. In order to maintain the economic calcium removal target of 70% preset by manufacturer, the dosing concentration of the soda ash was 530 mg/L based on influent flowrate. The seed concentration in the reactor was one of the critical factors and should be maintained in the range of $800\sim1,200mg$ SS/L to maximize the calcium removal efficiency. The calcite production rate was 0.30 g SS/g $Na_2CO_3$ in the average. The economic HVC passing time of the mixture was in the range of $2\sim5$ times. Relatively, stable calcium concentration was maintained in the range of $30\sim72$ mg/L(average 49 mg/L) although the calcium concentration in the feed was severely fluctuated with $74\sim359$ mg/L(average 173 mg/L). The HVC process was characterized as environment-friendly technology reducing chemical dosage and chemical sludge production and minimizing maintenance cost.

• Analytical Science and Technology
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• v.8 no.1
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• pp.91-99
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• 1995

One of alternative conventional technologies used for treatment of livestock wastes is composting process, and recently some mechanical composting processes are being practiced. It is, however, recognized the composting process also has its own limitations such as longer time requirement, and difficulties to estimate the degree of decomposition, etc. The incomplete compost contains potentially harmful materials to crops and public health due to instabilized organic contents and pathogenic organisms. The purpose of this investigation is to develop an innovative system whereby anxious livestock wastes are thoroughly stabilized and disinfected. Thus the overall management scheme should meet the following requirements. 1. A system should be in a cost-effective and environmentally sound manner. 2. Sludges must be chemically stabilized and bacteriologically safe. 3. Odor-free by product should be applied to crop land. 4. Sludges are sources of fertilizer nutrients and/or soil amendments to enhance crop production. 5. And they can be used as potential pH adjusting agent of the acidified soils. Overall effectiveness of the developed system is experimentally tested to satisfy the preset criteria and requirements. Major experiments are divided into four categories: they are 1. chemical stability test, 2. optimal condition test of stabilization process, 3. bacteriological examination and disinfection tests, and 4. deodorization tests The stabilization process is consisted of the stabilizing reaction process and the drying process. Stabilized wastes is dried by both sun dryer and rotary dryer. It is shown that an additive dosage of about g/kg solid in wastes with a minimum of 5-minutes reaction would be necessary for effective stabilization reaction. The stabilization process is consisted of the stabilizing reaction process and drying process. Stabilized wastes are dried by both sun dryer and rotary dryer. It is shown that an additive dosage of about 300g/kg solid in wastes with a minimum of 5-minutes reaction would be necessary for effective stabilization reaction. In the stabilization reaction process, the pH of wastes is lowered from initial values of 12.3 to 8.6. High pH prevents odor production and kills pathogenic organisms. Organic matter contents in the stabilized wastes are about 50% and the sum of contents of fertilizer elements such as total nitrogen, $P_2O_5$ and $K_2O$ are about 5.3%. The livestock wastes that are stabilized chemically and hygienically can be used as a good soil conditioner and/or organic fertilizer.

• Journal of Life Science
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• v.23 no.8
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• pp.1025-1031
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• 2013

From a 95% ethanolic extract of H. diffusa, four marker compounds (HD1~HD4) were isolated, which were relatively unique and exist in comparably high contents. The structures of marker compounds were identified as digitolutein (1), 2-hydroxy-3-methylanthraquinone (2), (E/Z)-6-O-p-coumaroyl scandoside methyl ester (4:1 mixture) (3), and (E/Z)-6-O-p-methoxycinnamoyl scandoside methyl ester (4:1 mixture) (4), respectively, on the basis of $^{13}C$ and $^1H$-NMR analyses. The calibration curves of marker compounds showed high linearity, as their correlation coefficient ($R^2$) were in the range of 0.9991~0.9999. In addition, the limit of detection (LOD) and the limit of quantification (LOQ) were $0.03{\sim}0.07{\mu}g/ml$ and $0.099{\sim}0.231{\mu}g/ml$, respectively. The intra-day/inter-day precision and accuracy were 0.23~2.00%/0.25~1.16% and 94.60~108.44%/94.73-110.23%, respectively. The optimal HPLC conditions for the simultaneous quantification of HD1~HD4 were as follows: stationary phase; Merck Chromolith RP-18e ($100{\times}4.6mm$, $5{\mu}m$), column temp.; room temperature, UV detection at 280 nm, flow rate; 2.0 ml/min, injection volume; $10{\mu}l$, mobile phase; start with the mixture of 80% solvent A ($H_2O$ containing 0.5% acetic acid) and 20% solvent B (methanol containing 0.5% acetic acid) and gradually decrease solvent A to 40% in 9 min., then retain this condition to 18 min. Under the HPLC condition, the four marker compounds 1~4 were successfully separated without any interference of other constituents. The results obtained in this study are expected to be helpful for the development of nutraceutics and natural medicines and for the quality control of this plant.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.2
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• pp.93-101
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• 1999

A simple experimental method was used in an attempt to realize the elevation of the fishing ability of purse seine in the sea area of Cheju Island, the changes of seine volume and tension in the purseline during pursing. Experiments carried out on the six types simplified reduced model seines which were made of knotless nettings. The nettings were woven in different leg length 4.3, 5.0, 5.5, 6.0, 6.6 and 7.7mm of polyester 28 tex two threads two-ply twine, and each of the seines were named I, II, III, IV, V and Ⅵ seine. Dimension of seine models were 450cm for corkline and 85cmfor seine depth, each seines rigged up 160g of float for a floatline and 50g (underwater weight) of lead for a leadline. These model purse seines were made of the scale of 1/200 of its full scale, a 120 ton in the near sea of Cheju Island. Designing and testing for the model purse seines were based on the Tauti's law. Experiments were measured in the observation channel of a flume tank at the static conditions set up shooting and pursing equipments. Motion of purse seine during purse line was recorded by the two sets video camera for VTR which were placed in top and front of the model seine. The reading coordinate of seine volume carried out by the video digitization system, disk data for the purseline tension. An analysis were performed on the changes seine volume and tension in the purseline during pursing. The results obtained were as follows: 1. The seine volume during pursing was largest for Ⅵ seine with smallest d/l followed by V, IV, III, II and I seines, and tension in the purseline was small. 2. Seine volume during pursing can be expressed by the following equation; CVt=l-EXP[｛2.79 (d/l）＋0.35｝t-33.37 (d/l) ＋ 0.57] Where CVt is volume ratio, d is twine diameter, l is leg length and t is pursing time (sec). 3. Tension in the purse line during pursing can be expressed by the following equation; T= 1- EXP ｛0.57t ＋ 13.36 (d/l)+2.97｝ Where T is tension (kg) in the purseline during pursing.

• Economic and Environmental Geology
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• v.49 no.4
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• pp.301-314
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• 2016

Disused Sealed Radioactive Sources (DSRSs) are stored temporally in the centralized storage facility of Korea Radioactive Waste Agency (KORAD) and planned to be disposed in the low- and intermediate-level radioactive waste (LILW) disposal facility in Gyeongju city. In this study, preliminary post-closure safety assessment was performed for DSRSs in order to draw up an optimum disposal plan. Two types of disposal options were considered, i.e. engineered vault type disposal and rock cavern type disposal which were planned to be constructed and operated respectively in LILW disposal facility in Gyeongju city. Assessment end-point was individual effective dose of critical group and calculated by using GoldSim code. In normal scenario, the maximum dose was estimated to be approximately $1{\times}10^{-7}mSv/yr$ for both disposal options. It meant that both options had sufficient safety margin when compared with regulatory limit (0.1 mSv/yr). Otherwise, in well scenario, the maximum dose exceeded regulatory limit of 1 mSv/yr in engineered vault type disposal and the exposure dose was mainly contributed by $^{226}Ra$, $^{210}Pb$ (daughter nuclide of $^{226}Ra$) and $^{237}Np$ (daughter nuclide of $^{241}Am$). For rock cavern type disposal, even though the peak dose satisfied regulatory limit, the exposure doses by $^{14}C$ and $^{237}Np$ were relatively high above 10% of regulatory limit. Therefore, it is necessary to exclude $^{14}C$, $^{226}Ra$ and $^{241}Am$ for two type of disposal options and additional management such as long-term storage and development of disposal container for those radionuclides should be performed before permanent disposal for conservative safety and security.

• Journal of Animal Environmental Science
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• v.17 no.1
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• pp.11-22
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• 2011

This work was carried out to investigate the quantity of manure excreta and characteristics in growth and production phase of Holstein dairy cattle. The average manure production of dairy cattle under condition of ad libitum feeding was 41.5 kg/head/day (feces 24.9, urine 16.4 kg). The average moisture contents of feces and urine were 85.0% and 93.9%, respectively. Water pollutant concentration, $BOD_5$, $COD_{Mn}$ and SS excreted from dairy cattle were 15,444 mg/${\ell}$, 53,159 mg/${\ell}$, and 40,528 mg/${\ell}$ in feces and 8,454 mg/${\ell}$1,116 mg/${\ell}$, and 962 mg/${\ell}$in urine, respectively. And The daily loading amount of $BOD_5$, $COD_{Mn}$, SS in dairy cattle manure were 523 g, 1,416 g and 1,025 g, respectively. N, P and K contents of manure produced by dairy cattle were 0.33, 0.49 and 0.20% in feces, and 1.02, 0.27 and 1.03 in urine, respectively. In the concentrations of mineral and heavy metal of manure, Ca, Na and Mg contents were 1.56, 0.24 and 0.69%, and Zn, Cu, Cr, Pb and As were 69.23, 19.14, 2.89, 7.73 and 2.94 ppm, respectively. In conclusion, Dairy farms can be estimated optimum nutrient and pollutant balance to effectively manage the manure produced.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.4
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• pp.79-90
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• 2013

The altitude range of habitats in which Fairy Pitta inhabited in 1960s is different from the present in Jeju Island. We studied on the habitat environment to understand the causes of difference through the comparison of satellite image data(Landsat) between 1975 and 2002, the literature review in relation to habitats, vegetations, and forest landscapes. The area of below 600m asl.(above sea level) where is mainly Fairy Pitta inhabited at the present with a lot of forests, was massive pasture with small isolated forests nearby valley. The forests were broad-leaved evergreen forests, and second forests with poor condition in the size and forest structure. The forests around 700m asl. were also second forests with approximately 3m height trees. The forests from 800m to 1300m asl. were also disturbed by mushroom cultivation by local people. The authors believe that Fairy Pitta could not inhabited in the area above 1300m because of the poor forest conditions in the size and structure in which consist of Ilex crenata, Rhododendron mucronulatum var. ciliatum and coppice forests. Therefore it might be possible that the best forests for the Fairy Pitta habitat were located in the area of 1,000m to 1,300m above sea level in 1960s. Compared to present habitats, forests at 100m up to 800m above sea level, the authors believe that the size of habitats were smaller with less population of Fairy Pitta. Since 1960s the forest landscape of Jeju Island has been improved successfully, and because of that the population of Fairy Pitta also has been increased. To protect the Fairy Pitta and habitats in Jeju Island, it is suggested that sustainable forest management focusing on the species composition and stand structure maintain or enhance the biodiversity.

• Korean Journal of Food Science and Technology
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• v.14 no.4
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• pp.301-308
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• 1982

Chungkook-jang Koji was fermented with rice straw at $40^{\circ}C\;and\;50^{\circ}C$ for 72 hours. The changes of proximate composition, pH, titrable acidity, nitrogen compounds, protease activity and free-amino acids during the fermentation were investigated. Moisture, lipid and protein contents remained essentially unchanged during the fermentation. The pH was gradually increased from 6.4 to 7.46 and 7.82 at $40^{\circ}C\;and\;50^{\circ}C$, respectively, after 72 hour fermentation. Amino type and water soluble nitrogen increased as fermentation progressed. however, the former slightly decreased after 60 hour fermentation. Chungkook-jang fermented at $40^{\circ}C$ showed somewhat higher protease activity than $50^{\circ}C$. However, protease activity at both fermentation temperatures showed the same trend; that is, it increased until 48 hour fermentation and thereafter decrease. Free amino acid content of Chung-kook-jang after 72 hour fermentation at $40^{\circ}C$ was 6 times greater than that of the steamed soybean, while it was 2.5 times greater at $50^{\circ}C$. Based on these results. it seems that the optimum fermentation conditions for Chungkook-jang were $40^{\circ}C$ and 72 hours.