• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.2
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• pp.59-67
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• 2017

The aim of this experiment was to investigate the effect of air suction rate (SR) during the composting process of swine manure mixed with sawdust used as a bulking agent. In the 25 L composting reactors, the suction rate (SR) was at four different treatment levels (100%, 200%, 300%, 400%), and were fixed on the based on constant aeration rate into the composting mixtures. The temperature reached to thermophilic phase within 2 days and it was maintained up to the $5^{th}$ day of the composting process in all reactors and then gradually decreased to room temperature at the end of the composting process. The moisture content (MC, %) of the initial mixtures was 64.27%, and it was reduced to 38.4, 33.08, 14.59 and 11.93 in the different suction rate of 100%, 200%, 300%, 400%, respectively in the end process. During the composting, the level of pH was increased from 6.83 to 8.67 and it gradually decreased to 7.56 in 100% and 200%(SR). At the same time, the pH values were reduced only up to 8.19 at 300%, and 8.08 at 400%(SR), showing that suction strengths of 100% and 200% were the better option for composting than those of 300% and 400%. The total Kjeldahl nitrogen (TKN) of initial composts mixtures was 2.3% and were changed in 3.3, 3.1, 2.5, and 2.3% at the end of the composting period from the 100%-400% (SR) variations respectively. These results also indicated that 100% and 200% (SR) were more affected by the dry mass loss as $CO_2$ and water evaporation. The initial value of C/N ratio was 25.17 and were significantly reduced to 11.88, 11.97, 14.31, and 14.72 at the end of the experiment, respectively from the 100%-400% (SR) variations. These results suggest that the suction rate (SR) of 100% and 200% relative to constant air supply would be the optimal conditions to produce high-quality compost.

• Korean Journal of Environmental Agriculture
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• v.2 no.2
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• pp.98-102
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• 1983

The hydrogen fluoride gas generated from making the cement hardener injured the plants growing at the neighbour field. This investigation was conducted on sample analysis of hydrogen fluoride gas damage plants which included the ratios of destroyed leaves, damage symptoms, and nutrient elements in paddy rice and weeds. The results obtained were as follows; 1) The ratio of destroyed leaves at near HF source was very high reaching about 95% at 100m, 65% at 500m, 5% at 2㎞, respectively. 2) The necrosis was the characteristic symptom of fluoride injury on rice plant and occurred predominantly at the tip and margins of damage leaf. It developed along the tip and margins of leaves with a dull, gray-green, water soaked discoloration. 3) The fluorine content of tip and margins of damaged rice leaves were 1,600 ppm, 3 to 20 times higher than that of center part and it ranged from 130 to 242.5 ppm in weed leaves, but from 10 to 15 ppm in normal weed leaves. 4) The contents of calcium, potassium, silicon, iron and manganese were higher in tip and margins than in the center of rice damage leaves. 5) The Cocculus trilolous. D.C was the most resistant plant to HF gas than any other plant growing in this site, while wild berry and aralia tree belong to most sensitive plant group.

• Economic and Environmental Geology
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• v.29 no.3
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• pp.235-246
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• 1996

Placer gold in collected heavy minerals from several localities in Huongkhe area, is consistently very finegrained (${\leq}100$ to $400{\mu}m$). The size and size distribution show somewhat differences at Dongdo and Hoahai : at Dongdo, predominant relatively larger and wide distribution; at Hoahai, characteristic relatively finer and narrow distribution range. The morphology of gold grains is divided into the four groups assumed by the dimension ratio : spherical, subprismoidal, prismoidal, and irregular. The gold grains at Dongdo show wide morphological distribution, whereas, at Hoahai, spherical form is predominant (${\approx}75%$). Three main types of gold are classified based on their chemical composition and mode of occurrence: type I (electrum; fineness=568~931), type II (amalgam; fineness=671~927), and type III (native gold; fineness=923~999). Type I gold contains, relatively high and variable silver contents (${\approx}11$ to 58 atomic % Ag), and has been classified into two subtypes based on their silver contents (type IA, ${\approx}11{\sim}39$ atomic % Ag; type IB, ${\approx}40{\sim}58$ atomic % Ag). However, type I gold would have been generally original compositions of electrum which originated at the provenance deposits. Mercury reacts with gold and silver to form amalgam (type II gold) which has variable Hg contents (1.2~30.5 atomic % Hg). The mercury contents in gold grains at Hoahai (10.9~30.5 atomic % Hg) are higher than those at Dongdo (5.8~21.1 atomic % Hg). The gold grains from the area generally exhibit a high-purity gold (type III) rim. The individual rims on the various grains range from <1 to $80{\mu}m$ in thickness and have silver contents of <10 atomic percent Ag, even though the core compositions range from ${\approx}11$ to 58 atomic percent Ag. The rim of gold most likely is responsible for the commonly cited cases of gold from placer deposits assaying at higher values of fineness than the gold in the corresponding source lode. The gold-rich rim in the Huongkhe area apparently forms by a combination of self-electrorefining and preferential dissolution of silver under oxidizing nature during the weathering and transport process. All data of gold grains in the Huongkhe area suggest that the transport distances and/or time of placer gold at Hoahai are generally farther than those at Dongdo. The mercurian gold bearing provenance deposits at Dongdo and Hoahai would be suggest nearest epithermal gold-silver vein-type.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.716-723
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• 1995

The fucoidan purified from Korean brown seaweed, Ecklonia stolonifera was characterized on molecular structure and blood anticoagulant activities. Extraction was conducted at $100^{\circ}C$ with water and repeated twice. The crude fucodian was 151.1g out of 20.0 kg of Ecklonia stolonifera. The Fucoidan-1, which was purified from crude fucoidan using calcium chloride and cetyl pyridium chloride (CPC), was 35.2% against crude fucoidan. Fucoidan-5 was obtained approximately 28.1% from Fucoidan-1 through DEAE-Toyopearl 650 M ion-exchange column chromatography and showed one band by cellulose acetate electrophoresis. The molecular weight of Fucoidan-5 was estimated to be about 21,000∼23,000 dalton by Sephacryl S-300 gel filtration chromatography. Fucoidan-5 consists of 35.7% of fucose and 4.3% of galactose and the molar ratio of fucose and sulfate was about one to one. IR spectrum of Fucoidan-5 showed absorption at $1240\;cm^{-1}\;and\;850\;cm^{-1}$ and specific rotation value, $[\alpha]$, was $[\alpha]$. These results suggests that the sulfate maybe bind at $C_{4}$ carbon on ${\alpha}-L-fucose$. Gas chromatograph of methyl alditol acetate revealed that Fucoidan-5 is a fucose containing sulfated polysaccharide with $({\alpha}l-2)\;or\;({\alpha}l-2)$ glycosidic linkage. Anti-thrombin activity of the Fucoidan-5 was estimated as 1.4 time stronger than heparin. From above results, the purification methods using CPC and ion exchange chromatography is effective tools for obtaining highly purified fucoidan from Gompi, Ecklonia stolonifera.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.248-256
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• 2007

In this paper, we propose a selective DFT spreading method to solve a high PAPR problem in uplink OFDMA system. A selective characteristic is added to the DFT spreading, so the DFT spreading method is mixed with SLM method. However, to minimize increment of computational complexity, differently with common SLM method, our proposed method uses only one DFT spreading block. After DFT, several copy branches are generated by multiplying with each different matrix. This matrix is obtained by linear transforming the each phase rotation in front of DFT block. And it has very lower computational complexity than one DFT process. For simulation, we suppose that the 512 point IFFT is used, the number of effective sub-carrier is 300, the number of allowed sub-carrier to each user's is 1/4 and 1/3 and QPSK modulation is used. From the simulation result, when the number of copy branch is 4, our proposed method has more than about 5.2 dB PAPR reduction effect. It is about 1.8 dB better than common DFT spreading method and 0.95 dB better than common SLM which uses 32 copy branches. And also, when the number of copy branch is 2, it is better than SLM using 32 copy branches. From the comparison, the proposed method has 91.79 % lower complexity than SLM using 32 copy branches in similar PAPR reduction performance. So, we can find a very good performance of our proposed method. Also, we can expect the similar performance when all number of sub-carrier is allocated to one user like the OFDM.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.733-742
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• 2000

Fundamental materialistic characterization and adsorption/neutralization behavior of waste egg shell for heavy metal ion have been studied for its application to wastewater treatment. To investigate the structural change and thermal decomposition characteristics of egg shell. X-ray diffraction and FT-IR analysis were conducted for egg shell treated at $105^{\circ}C$ and $700^{\circ}C$, respectively. For the result of FT-IR analysis, the sample treated at $700^{\circ}C$ showed a reduced C-O absorption band compared with that of egg shell treated at $105^{\circ}C$, which may be due to the $CO_2$ release. Unlike to the result of FT-IR analysis, the XRD patterns of egg shell were almost similar for the cases of $105^{\circ}C$ and $700^{\circ}C$ treatment. however, characteristic diffraction pattern of CaO was observed for $850^{\circ}C$ treatment, at which $CaCO_3$ is known to be completely converted to CaO. TGA/DTA analysis showed a slow decline in weight loss up to $600^{\circ}C$ and, for $600{\sim}800^{\circ}C$ range, the weight loss became drastic by reason of $CO_2$ discharge, which was accompanied by an appearance of major endothermic peak. The ratio of practical breakthrough time to ideal one, total transfer unit, and mass transfer coefficient were observed to be increased as the adsorption was progressed in a multiple-column fixed-bed reactor using egg shell as an adsorbent, which signified the distribution effect of mass transfer for continuous adsorption reaction. The neutralization effect of egg shell for several types of acidic wastewater made of different mineral acids was not much different from each other except for the case of $H_2SO_4$, for which the neutralization reaction was thought to be retarded by the formation of gypsum.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.219-226
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• 2010

In order to evaluate a removal characteristic of chloramphenicol, salicylic acid and ketoprofen according to dose of oxidants, $Cl_2$, $O_3$ and $O_3/H_2O_2$ are used as oxidants in this study. In case of that $Cl_2$ is used for oxidizing harmaceuticals, chloramphenicol, salicylic acid and ketoprofen is not removed entirely at $Cl_2$ dose rang of 0.5~5.0 mg/L for 60 min. However, removal tendency of salicylic acid is so obviously at $Cl_2$ dose higher than 1.0 mg/L. In addition, as $Cl_2$ dose and contact time increase, the removal rate of salicylic acid is enhanced. When $O_3$ is used as oxidant, chloramphenicol and ketoprofen is not eliminated at $O_3$ dose range of 0.2~2.0 mg/L. On the contrary, 30~70% of salicylic acid is removed at $O_3$ dose of 1.0~5.0 mg/L. Only 30% removal of salicylic acid is achieved at contact time of 5 min, however, the removal rate is enhanced remarkably at contact time over 10 min. In experiments using $O_3/H_2O_2$ as an oxidant, we can find that $O_3/H_2O_2$ is much more effective than $O_3$ only for removal of 3 pharmaceuticals, and the efficiency is raised according to increase of $H_2O_2$ dose. On reaction rate constant and half-life of 3 pharmaceuticals depending on $Cl_2$, $O_3$ and $O_3/H_2O_2$ dose, experiments using $O_3/H_2O_2$ show that oxidation of pharmaceuticals is less effective as the $H_2O_2/O_3$ ratio increases to above pproximately 1.0 related to reaction rate constant. An oxidation of salicylic acid by $Cl_2$ and $O_3$ particularly has a comparatively high reaction rate constant comparing $O_3/H_2O_2$, and thus salicylic acid is easily eliminated in oxidation processes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.1
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• pp.1-13
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• 1989

The present study was designed to examine the effect of dietary fish oil on blood pressure and lipid status of serum. Weanling SHRs and normotensive Wistars were fed a diet containing 5%(w/w) mackerel oil(MO), soybean oil(SO) or beef tallow(BT) for 8 weeks. Growth rate was not significantly different among three dietary groups, but that of SHRs was silightly lower than that of Wistars. SHRs showed higher systolic blood pressure than Wistar rats from the beginning and become hypertensive (over 150mmHg) after 6 week s of feeding period. The MO group of SHRs showed the lowest blood pressure at the 8th week of feeding period but that of Wistars showed similar values with other groups. Tissue weights of liver, heart and kidney were not different amongdietary aroups in Wistars and SHRs. However, heart and kidney weights of SHRs were significantly higher than those of Wistars. Microscopic examination revealed that endomysium of heart tissue and urinary space of kidney were narrowed in SHRs. Serum total and HDL-cholesterol showed similar values among three different dietary fat groups but triglyceride levels were significantly low in MO groups. HDL-cholesterol levels of SHRs were lower than those of Wistars, as well as the fractions of total HDL, the sum of HDL and $HDL_{2+3}$, while VLDL fractions were higher in SHRs. MO groups had the lower values of $HDL_1,\;HDL_{2+3}$ratio than SO and BT groups. Major dietary fatty acids were more or less incorporated into serum phospholipid and triglyceride, resulting in the characteristic fatty acid profile of each dietary group. Incorporation of $C_{18:2}({\omega}_6)$ in SO groups were pronounced, but the degree of incorporation was lower in SHRs. In Mo groups, $C_{22:6}({\omega}_3)$ levels were inreased in triglyceride. It is suggested that these changes in serum lipid fatty acid composition are related to the different patterns of serum lipid by alteration of dietary fats.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.4
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• pp.89-101
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• 2017

Crime occurs differently based on not only place locations and building uses but also the characteristics of the people who use the place and the spatial structures of the buildings and locations. Therefore, if spatial big data, which contain spatial and regional properties, can be utilized, proper crime prevention measures can be enacted. Recently, with the advent of big data and the revolutionary intelligent information era, predictive policing has emerged as a new paradigm for police activities. Based on 7420 actual crime incidents occurring over three years in a typical provincial city, "J city," this study identified the areas in which crimes occurred and predicted risky areas. Spatial regression analysis was performed using spatial big data about only physical and environmental variables. Based on the results, using the street width, average number of building floors, building coverage ratio, the type of use of the first floor (Type II neighborhood living facility, commercial facility, pleasure use, or residential use), this study established a Crime Incident Prediction Model (CIPM) based on Bayesian probability theory. As a result, it was found that the model was suitable for crime prediction because the overlap analysis with the actual crime areas and the receiver operating characteristic curve (Roc curve), which evaluated the accuracy of the model, showed an area under the curve (AUC) value of 0.8. It was also found that a block where the commercial and entertainment facilities were concentrated, a block where the number of building floors is high, and a block where the commercial, entertainment, residential facilities are mixed are high-risk areas. This study provides a meaningful step forward to the development of a crime prediction model, unlike previous studies that explored the spatial distribution of crime and the factors influencing crime occurrence.

• Tuberculosis and Respiratory Diseases
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• v.41 no.6
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• pp.624-631
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• 1994

Background: Genus of Aspergilli are ubiquitous saprophytic molds in nature, but its change from a saprophytic fungus to a pathogenic organism has occurred since the use of various antibiotics. The fungus affects the chronically ill and debilitated population. Recently frequency of the fungal infection is increasing in Korea with abuse of antibiotics and glucocorticoids. Method: We analyzed medical records of 52 patients with pulmonary aspergillosis seen at Hanyang University Hospital from 1980 to 1994. The results were as follows; Results: 1) Ages ranged between second to eighth decades with majority(50%) in the fourth to fifth decades. The male to female ratio was 1.1:1. 2) Hemoptysis and productive cough, the leading symptoms, occurred in 42.3% and 25% respectively. 3) On chest X-ray fingings, the characteristic "fungus ball" pattern were observed in 53.8% of the 52cases. 4) Sputum culture for aspergilli were positive in 21.6% of the cases. We performed fine needle aspiration in 22 patients and the diagnostic yield was 100%. 5) Thirty-six patients had history of treatment with antituberculous drugs under diagnosis of pulmonary tuberculosis for an average of 27.3 months. But sputum analysis for acid-fast bacilli were positive in 5.6%(2cases of 36cases), and postoperative pathologic findings showed that 38.9%(12 cases of 28cases) were combined with tuberculosis. 6) Right upper and left upper lobes were predominantly involved(34.6% and 19.2% respectively) and lobectomies were performed in 21 cases. 7) Underlying diseases were present in 47 cases and 48.9% of them were pulmonary tuberculosis. Conclusion: These results showed that pulmonary aspergillosis usually develops in patients with open cavitary pulmonary tuberculosis. And we must consider the possibility of pulmonary aspergillosis in a patient with hemoptysis and cavitary lung lesion.