• Food Science and Preservation
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• v.8 no.3
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• pp.279-285
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• 2001

The effect of chitosan and cacium treatment on the quality of satsuma mandarin(Citrus unshiu Marc. var. miyagawa) during storage were investigated. Citrus fruits treated with 2000-folds diluted iminoctadime-triacetate solution or 1.5% chitosan with 0.5% CaCl$_2$ solution were stored at 4$\^{C}$ and 87$\pm$3% relative humidity, and room temperature without humidity control. Decay ratio of chitosan and calcium treated fruits were lower than the ones with no treatment from the mid of February. Also, citrus fruits treated with chitosan and calcium treated less in weight loss, that seems it was derived from restraining of fruits' transpiration. Soluble solids were maintained higher level in chitosan and calcium treated fruits than with no treatment during the storage. Acid contents were decreased gradually lower in cold storage than in room temperature storage, and there was not showed consistent trend among treatments. 26 kinds of free amino acids among 45 standards such as glutamic acid, threonine, serine, alanine γ-amino buryric acid, aspragine and etc were detected in Citrus unshiu Marc. var. miyagawa. As the storage time was prolonged, free amino acid was disappeared more or less, and the deccreasing extent was less in 4$\^{C}$ than in room temperature storage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.4
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• pp.279-283
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• 2004

This experiment was carried out at paddy field (commercial silty loam soil) in the southwestern Korea. Pungsannamulkong, a determinate growth habit, was a relatively high yielding and late maturing cultivar, and Han­namkong, a semi determinate growth habit, was a relatively low yielding and early maturing cultivar. Seeds were sowed at two plants and with a planting density of $70{\times}10cm$ on May 26, 2003. Fertilizer was applied prior to planting at a rate of 3.0-3.0-3.4g $(N-P_2O_5-K_2O)\;per\;m^2$ by all basal fertilizations. Experimental design was a randomized complete block with three replications. Seed yield was higher in Pungsannamulkong by 362g per $m^2$ than in Hannamkong of 260g per $m^2$ Also, the number of pod, number of seed, and number of seed per pod were greater in Pungsannamulkong than in Hannamkong. The number of leaves per $m^2$ showed similar with two soybean cultivars up to August 24 but thereafter it decreased in Hannamkong. The leaf area up to August 4 increased in Hannamkong higher than in Pungsannamulkong, but after that time, Pungsannamulkong had greater leaf area than Hannamkong. The shoot and leaf dry matter of two soybean cultivars from June 23 to August 4 were similar but thereafter, Pungsannamulkong had a significantly greater than Hannamkong. Crop growth rate (CGR), relative growth rate (RGR) and net assimilate rate (NAR) for Punsannamulkong were relatively higher than Hannamkong but leaf area ratio (LAR) and specific leaf weight (SLW) showed higher in Hannamkong. Most of leaves distributed in the ranges of 80-90cm and 60-70cm from the soil surface in Punsannamulkong and Hannamkong, respectively. Pods of Punsannamulkong ranged 10-80cm from the soil surface and most of pods were distributed at 40-50cm. Photosynthetic rate at the flowering stage showed a significant difference between cultivars in the upper most leaf position. There was no significant difference of the photosynthetic rate at $7^{tn}$ leaf at the flowering stage, and the uppermost and 7th leaf position at the seed development stage between two soybean cultivars.

• Korean Journal of Environmental Biology
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• v.29 no.2
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• pp.98-106
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• 2011

In order to investigate water quality factors controlling chlorophyll-$a$ concentrations, the by-daily monitoring was conducted from February to November 2010 in 4 stations of Masan Bay. Seasonal variability in physico-chemical factors was mainly controlled by freshwater loading as a result of precipitation: chemical oxygen demand, suspended solids and nutrient concentrations rapidly increase during the heavy rainy season, whereas they decrease in the dry season. From late winter to mid spring, phosphorus and silica sources relative to Redfield ratio were probably functioned as limiting factor for phytoplankton flourishing in surface waters, but nitrogen concentration during mid-spring to autumn might be responsible for the increase of phytoplankton biomass. The multiple regression analysis revealed that variations in chlorophyll-$a$ concentration may be strongly correlated with changes of water temperature, chemical oxygen demand, dissolved inorganic phosphorus in spring, and salinity, chemical oxygen demand and precipitation in summer. Consequently, in the Masan Bay, a heavy rainfall event is an important factor to determine changes of biotic and abiotic factors, and in addition the dynamics of chlorophyll-$a$ concentration are strongly affected by changes of hydrological factors, especially water temperature, precipitation and nutrients.

• Toxicological Research
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• v.23 no.4
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• pp.353-362
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• 2007

Deoxynivalenol (DON) is a common food borne mycotoxin and occurs predominantly in grains such as wheat, barley, oats, etc. DON induces systemic health problems such as loss of appetite, emesis and diarrhea in both human and farm animals. Reliable diagnostic parameters for DON intoxication are needed to prevent deep health impact. In order to establish useful diagnostic parameters, we investigated clinical signs, hematological values, serum biochemical values, gross-, histo- and toxico-pathological findings in B6C3F1 male mice after oral administration of DON (0.83, 2.5 and 7.5 mg/kg) for 8 days. Body weight gain was significantly decreased at the highest dose of DON. Anorexia, ataxia, for crudness and lack of vigor were observed at the highest dose DON group. In hematological values, the numbers of WBC and platelets and hemoglobin content were reduced with decreased neutrophil and monocytes by 7.5 mg/kg DON. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) were prolonged in a dose-dependent manner and the content of fibrinogen was elevated at high dose of DON. Of serum biochemical values, total protein, globulin, BUN, cholesterol and test-osterone were reduced but total bilirubin and albumin/globulin ratio increased. The enzyme activity of alkaline phosphatase was decreased while that of alanine aminotransferase was elevated. Relative organ weights of thymus, seminal vesicle/prostate and testes were dose-dependently reduced but those of liver and left adrenal gland increased with dose dependency. As for pathological findings, atrophy of thymus, seminal vesicle/prostate and testes and submucosal edema and ulceration in stomach and depletion of lymphocytes in thymus cortex were observed. In conclusion, these clinical, hematological, blood biochemical and patholgical parameters obtained in the present studies can be used for diagnosis of DON-mycotoxicosis, especially, low WBC, platelets, protein, BUN and testosterone and delayed prothrombin time can be available as for reliable diagnostic parameters.

• Journal of the Korean Wood Science and Technology
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• v.39 no.6
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• pp.459-468
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• 2011

The main purpose of this study was to examine the influence of treatment amounts of Slurry Composting and Biofiltration liquid fertilizer (SCBLF) on biomass growth of Yellow poplar (Liriodendron tulipifera) and to compare bioethanol production from the harvested wood. Relative growth rate, biomass production and leaf characteristics were significantly enhanced by SCBLF treatment and medium treatment plot showed highest value. Nitrogen compounds and water content in SCBLF affected to increase chlorophyll contents which led improving biomass production (64.67%) and glucose contents (6.07%) than control. Organosolv and dilute acid pretreatments were preliminarily carried for bioethanol production, and the pretreatment processes were conducted at all the same solid to liquid ratio (1 : 10), reaction temperature ($150^{\circ}C$), preheating time (40 min) and residence time (10 min). The water insoluble solid recovery of Organosolv pretreatment with 1% sulfuric acid as a catalyst was the lowest and that of medium treatment plot was 44.81%. Exchangeable cations in SCBLF might be affected to increase pretreatment effect. The simultaneous saccharification and fermentation process was followed to determine the ethanol production of the pretreated biomass. The highest ethanol production yield based on initial weight was obtained from high treatment plotby Organosolv pretreatment with 1% sulfuric acid (16.11%). But regarding biomass production, medium treatment plot produced most, and bioethanol production was increased by 72.93% than control.

• Journal of Food Hygiene and Safety
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• v.11 no.4
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• pp.243-259
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• 1996

This study was performed to investigate the induction of experimental atherosclerosis in rats and inhibitory effects of aloe vera on progression of atherosclerosis in rats. Adose range finding study of cholesterol and vitamin D2 for the induction of atherosclerosis and studies on the subchronic effect of aloe vera and on the chronic effect of aloe vera were carried out. A total of 3-week old 125 male rats of Sprague-Dawley were divided into 25 groups and fed with the diet containing cholesterol (0.1, 0.2, 0.3, 0.5, 1.0 and 2.0%) and vitamin D2 (500, 5000, 50000 and 500, 000 IU/100 g) for 4 weeks. 35 male rats were divided into 7 groups and fed with the diet containing aloe vera with 1.0% of cholesterol and 50, 000 IU/100 g of vitamin D2 for 4 weeks. 200 male rats were divided into 5 groups and fed with cholesterol and vitamin D2 for 6 and 12 months. Growth, clinical and pathological changes of rats in the three experiments were observed. The results were as follows: 1. In the dose-range finding study, feed intake, feed efficiency ratio and weight to body weight were increased in all of the feed groups containing 500, 000 IU/100 g of vitamin D2. Serum biochemical values of total cholesterol, high-density lipiprotein cholesterol (HDL-cholesterol), triglyceride, calcium, inorganic phosphorous and chloride of male rats in treated groups. The aorta and coronary artery of rats in all of the diet group containing 500, 000 IU/100 g of vitamin D2 showed typical atherosclerotic lesions. 2. Male rats fed with the diet containing aloe vera with 1.0% cholesterol and 50, 000 IU/100 g of vitamin D2 for 6 and 12 months did not show significant difference of diet intake and weight gain, and relative organ weight. The level of serum HDL-cholesterol and triglyceride recovered to the normal range by the aloe vera ingestation. 3. The aorta showed irregular appearence in the tunica intima with swelling, necrosis and calcification. The aorta of rat fed aloe vera diet showed no pathological lesions such as atherosclerosis of aorta. Aloe vera could have a helpful effect of vitamin D2 and cholesterol induced atherosclerosis in rats. Long-term supplementation of aloe vera may slow down the process of experimental atherosclerosis in rats have effects on the development of atherosclerosis.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.1
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• pp.21-26
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• 1992

Generally a navigator evaluated the maneuverability of his ship by the scale of turning circle which was described only by the largest rudder angle of the port and starboard sides. But to have the sufficient knowledge of his ship's maneuvering characteristics he should consider the data about the new course keeping test, the spiral test, and the turning circle tests in accordance with the rudder angles together. In this paper the author performed the above tests to study the maneuverability of the stern trawler M.S. Pusan 404 which is a training ship of the National Fisheries University of Pusan. The obtained results are summarized as follows: 1. When the rudder angles being 5。, 10。, 20。, 30。, 35。 the advances of the starboard side turning circles were 12.8, 8.2, 4.8, 2.9, 2.7 times as large as the length of the ship, and of the port side turning circles were 13.3, 8.7, 5.4, 3.5, 2.9, time as large as the large as it. Under the same conditions the tactical diameters were 15.1, 9.7, 5.2, 3.1, 2.8 times as large as the length of the ship, for starboard side, and 17.2, 12.4, 6.4, 3.7, 3.2 times as large as it for port side. 2. As the rudder angle being increased the ratio of the advance to the tactical diameter was nearly 1 and her obeying ability was better than that of the small angle. 3. The mean values of the rates of speed reduction during the steady turning motion were 0.96, 0.92, 0.82, 0.71, 0.65 in accordance with the rudder angles. 4. The relative formulas between the distance to the new course y and the altering course x were as follows: When rudder angles being 10。, 20。, 30。, y=52.2222+1.6133x, y=48.750+0.9383x, y=39.250+0.655x respectively. 5. There was little difference of the distance to the new course between rudder angle 20。and 30。, and so it is desirable for a navigator to a navigator to use the small rudder angles unless sudden emergencies. 6. Though her rudder angle being small her course stability was good according to the spiral tests.

• Journal of the Korea Concrete Institute
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• v.27 no.6
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• pp.677-685
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• 2015

In a will to subdue the brittleness as well as the low tensile and flexural strengths of ordinary concrete, researches are being actively watched worldwide on steel fiber-reinforced Ultra High Performance Concrete (UHPC) obtained by admixing steel fibers in ultra high strength concrete. For the purpose of maximizing advantage of UHPC, this study removes the upper flange of the steel girder to apply an inverted T-shape girder for the formation of the composite beam. This paper intends to evaluate the behavior of the shear connectors and the flexural characteristics of the composite beam made of the inverted T-shape girder and UHPC slab using 16 specimens considering the compressive strength of concrete, the mixing ratio of steel fiber, the spacing of shear connectors and the thickness of the slab as variables. In view of the test results, it seemed that the appropriate stud spacing should range between 100 mm and 2 or 4 times the thickness of the slab. Moreover, the relative displacement observed in the specimens showed that ductile behavior was secured to a certain extent with reference to the criteria for ductile behavior suggested in Eurocode-4. The specimens with large stud spacing exhibited larger values than given by the design formula and revealed that the shear connectors developed larger ultimate strength than predicted owing to the action of UHPC and steel after non-composite behavior. Besides, the specimens with narrow stud spacing failed suddenly through compression at the upper chord of UHPC before reaching the full capacity of the shear connectors.

• Journal of Environmental Health Sciences
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• v.28 no.2
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• pp.117-129
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• 2002

Concentration of welding fumes and their components is known to be hazardous to welder and adjacent worker. To determine the generation rates of metals in fumes, $CO_2$ flux cored arc welding on stainless steel was performed in well designed fume collection chamber. Variables were different products of flux cored wire(2 domestic products and 4 foreign products) and input energy(low-, optimal- , high input energy). Mass of welding fumes was determined by gravimetric method(NIOSH 0500 method), and 17 metals were analysed by inductively coupled plasm-atomic emission spectroscopy(NIOSH 7300 method). Flux cored wire tube and flux were analysed by scanning electron microscopy to determine their metal composition. 17 metals were classified by their generation rates. Generation rates of iron, manganese, potassium and sodium were all above 50mg/min at optimal input energy level. Generation rates of chromium and amorphous silica were 25~50mg/min. At 1~25mg/min level, nickel, titanium, molybdenum, and aluminum were included. Copper, zinc, calcium, lead, magnesium, lithium, and cobalt were generated below 1 mg/min. Generation rates of metal components in fumes were influenced by input energy, types of flux cored wire. Flux cored wire was consisted of outer shell tube and inner flux. Iron, chromium, and nickel were the major components of outer tube. Flux contained iron, chromium, nickel, potassium, sodium, silica, and manganese. The use of flux cored wire can increase the hazards by increasing the amounts of fumes formed relative to that of solid wire. The reason might be the direct transfer of elements from the flux, since the flux is fine power. Ratio of metals to the fume of flux cored wire was lower than that of solid wire because non-metal components of flux were transferred. Total metal content of fumes in flux cored arc welding was 47.4(24.3~57.2) percent that is much lower than that of solid wire, 75.9 percent. We found that generation rates of iron, manganese, chromium and nickel, all well known to cause work related disease to welder, increased more rapidly with increasing input energy than those of fumes. To reduce worker exposure to fumes and hazardous component at source, further research is needed to develop new welding filler materials that decrease both the amount of fumes and hazardous components.

• Journal of the Korean Geotechnical Society
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• v.20 no.7
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• pp.127-140
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• 2004

Conventional methods for the assessment of liquefaction potential were primarily for areas of severe earthquake zones (M=7.5) such as North America and Japan. Detailed earthquake related researches in Korea started in 1997, including development of the seismic design standards for port and harbour structures, which was later completed in 1999. Because most contents in the guidelines were quoted through literature reviews from North America and Japan, which are located in strong earthquake region, those are not proper in Korea, a moderate earthquake region. This requires further improvement of the present guidelines. Considering earthquake hazard data in Korea, use of laboratory tests based on irregular earthquake motion appears to be effective to reflect the dynamic characteristics of soil more realistically than those using simplified regular loading. In this study, cyclic triaxial tests using irregular earthquake motions are performed with different earthquake magnitudes, relative densities, and fines contents. Assessment of liquefaction potential in moderate earthquake regions is discussed based on various laboratory test results. Effects of these components on dynamic behavior of soils are discussed as well. From the test results, screening limits and magnitude scaling factors to determine the soil liquefaction resistance strength in seismic design were re-investigated and proposed using normalized maximum stress ratios under real irregular earthquake motions.