• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.151-159
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• 2012

Direct seeding of rice is a time- and laborsaving method, compared to machine transplanting. However, the area planted to direct-seeded rice is decreasing because of instability of seedling establishment, lodging, occurrence of weedy rice, and deterioration of grain quality. A newly developed wet-hill-seeding of rice, a type of direct seeding method, has shown features of growth similar to machine transplanted rice. This study was carried out to compare tillering pattern, heading characteristics and grain filling traits between transplanting and wet-hill-seeding in rice. Tillering of wet-hill-seeded rice was more vigorous than that of transplanted rice showing maximum tiller number 30~100% higher than transplanted rice. Wet-hill seeded rice showed later heading and shorter heading duration than transplanted rice. To find out the relationship between heading characteristics and grain filling traits, every panicle was tagged for flowering date, and the panicles on each heading date were inspected for grain filling traits. Wet-hill seeded rice and transplanted rice exhibited no significant difference in culm length, panicle length, the percentage of grain filling and perfect brown rice on each heading date during total heading period. Therefore, we conclude that wet-hill-seeding method is not inferior to machine transplanting in terms of seedling establishment, growth, grain filling and head rice yield.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.1
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• pp.16-25
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• 2012

To calculate the total mass flux that change in dry and flood season in the Yeomha Channel of Gyeonggi Bay, the 13 hour bottom tracking observation was performed from the southern extremity. The value of the total mass flux(Lagrange flux) was calculated as the sum of the Eulerian flux value and stroke drift value and the tidal residual flow was harmonically analyzed through the least-squares method. Moreover, the average during the tidal cycle is essential to calculate the mass flux and the tidal residual flow and there is the need to equate the grid of repeatedly observed data. Nevertheless, due to the great differences in the studied region, the number of vertical grid tends to change according to time and since the horizontal grid differs according to the transport speed of the ship as a characteristic of the bottom tracking observation, differences occur in the horizontal and vertical grid for each hour. Hence, the present study has vertically and horizontally normalized(sigma coordinate) to equate the grid per each hour. When compared to the z-level coordinate system, the Sigma coordinate system was evaluated to have no irrationalities in data analysis with 5% of error. As a result of the analysis, the tidal residual flow displayed the flow pattern of sagging in the both ends in the main waterway direction of dry season. During flood season, it was confirmed that the tidal residual flow was vertical 2-layer flow. As a result of the total mass flux, the ebb properties of 359 cm/s and 261 cm/s were observed during dry and flood season, respectively. The total mass flux was moving the intertidal region between Youngjong-do and Ganghwa-do.

• Korean Journal of Environmental Agriculture
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• v.36 no.2
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• pp.67-72
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• 2017

BACKGROUND:Cultivation of alternative crops in paddy fields is necessary because of the decrease in rice consumption and the increase in excess stock of rice. The study was conducted to investigate the effects of alternative crops cultivation in paddy fields on soil physico-chemical characteristics and crop yield. METHODS AND RESULTS: Soybean (Glycine max), red-clover (Trifolium pratense), and water convolvulus (Ipomoea aquatica) were selected for alternative crops in the first and/or second year and rice was planted in the third year. When alternative crops were cultivated in the previous year, soil bulk density, soil hardness, and water content were lower than those for rice cultivation. Water-depth decreasing rate and aggregate content were greater for the upland-upland-paddy cropping system than upland-paddy-paddy cropping system. Cultivation of red-clover and water convolvulus for two years resulted in the high soil organic matter content. In the third year, available phosphate, exchangeable potassium, and soil cation exchange capacity were relatively high when soybean was cultivated in the previous year. In the first year, water convolvulus cultivation showed greater productivity than red-clover cultivation while the opposite pattern was found in the second year. Rice yield in the third year was greater for soybean or red-clover as a previous crop than for water convolvulus as a previous crop. CONCLUSION: The results suggest that cultivation of alternative crops in paddy fields can improve soil physical properties including bulk density, hardness, water content, and aggregate content as well as rice productivity.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.3
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• pp.265-272
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• 1999

In this study in order to know the behavior of mineral nutrients from forage plant to soil in a grassland ecosystem, the leaching of minerals (K, Mg, Ca, N and P) from air-dried (dead) plant body was investigated by putting orchardgrass (Dactylis glomerata L.) hay on meadow during a month with seasonal changes. The results obtained were as follows; 1) The K content of the forage, not stable during the experimental seasons, tended to decrease in the summer of 1986, while the Mg and Ca contents increased in the summer. The reason might be a different response (solubility or leaching liability) of the monovalent mineral (K) and divalent ones (Mg and Ca) in the forage to rainfall. 2) The percentage of P to the initial amount in the forage showed larger decrease in a rainy period (Feb.~Mar., 1986) and during the rainy summer (May to July). The P component of the forage might be easily leached with water. 3) The percentage of the four minerals (Ca, N, Mg, K) remained the least in the period of (Jun.~Jul., 1986), 4) Though the percentage of remained Mg and N of the forage varied very similarly, the percentage of remained N was higher than that of Mg during periods before summer (January to May), while after the period the ratio of the Mg seemed to be higher than that of the N (June to December), 5) During the periods until (May~Jun., 1986) the percentage of remained K and P of the forage varied in very similar pattern, and the order of remained mineral was as follows; $Ca>N{\geq}Mg>P=K$. But from the period of (Jun-Jul) the ratio of P remained in the forage increased nearly up to the ratio of N, and the order was as follows; $Ca>Mg{\geq}N{\geq}P>K$.

• Journal of Oral Medicine and Pain
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• v.32 no.2
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• pp.137-150
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• 2007

Trees emit phytoncide into atmosphere to protect them from predation. Phytoncide from different trees has its own unique fragrance that is referred to as forest bath. Phytoncide, which is essential oil of trees, has microbicidal, insecticidal, acaricidal, and deodorizing effect. The present study was performed to examine the effect of phytoncide on Porphyromonas gingivalis, which is one of the most important causative agents of periodontitis and halitosis. P. gingivalis 2561 was incubated with or without phytoncide extracted from Hinoki (Chamaecyparis obtusa Sieb. et Zucc.; Japanese cypress) and then changes were observed in its cell viability, antibiotic sensitivity, morphology, and biochemical/molecular biological pattern. The results were as follows: 1. The phytoncide appeared to have a strong antibacterial effect on P. gingivalis. MIC of phytoncide for the bacterium was determined to be 0.008%. The antibacterial effect was attributed to bactericidal activity against P. gingivalis. It almost completely suppressed the bacterial cell viability (>99.9%) at the concentration of 0.01%, which is the MBC for the bacterium. 2. The phytoncide failed to enhance the bacterial susceptibility to ampicillin, cefotaxime, penicillin, and tetracycline but did increase the susceptibility to amoxicillin. 3. Numbers of electron dense granules, ghost cell, and vesicles increased with increasing concentration of the phytoncide, 4. RT-PCR analysis revealed that expression of superoxide dismutase was increased in the bacterium incubated with the phytoncide. 5. No distinct difference in protein profile between the bacterium incubated with or without the phytoncide was observed as determined by SDS-PAGE and immunoblot. Overall results suggest that the phytoncide is a strong antibacterial agent that has a bactericidal action against P. gingivalis. The phytoncide does not seem to affect much the profile of the major outer membrane proteins but interferes with antioxidant activity of the bacterium. Along with this, yet unknown mechanism may cause changes in cell morphology and eventually cell death.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.424-434
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• 2009

Statement of problem: Problems such as loosening and fractures of retained screws and fracture of implant fixture have been frequently reported in implant prosthesis. Purpose: Implant has weak mechanical properties against lateral loading compared to vertical occlusal loading, and therefore, stress analysis of implant fixture depending on its material and geometric features is needed. Material and methods: Total 28 of external hexed implants were divided into 7 of 4 groups; Group A (3i, FULL $OSSEOTITE^{(R)}$Implant), Group B (Nobelbiocare, $Br{\aa}nemark$ $System^{(R)}$Mk III Groovy RP), Group C (Neobiotec, $SinusQuick^{TM}$ EB), Group D (Osstem, US-II). The type III gold alloy prostheses were fabricated using adequate UCLA gold abutments. Fixture, abutment screw, and abutment were connected and cross-sectioned vertically. Hardness test was conducted using MXT-$\alpha$. For fatigue fracture test, with MTS 810, the specimens were loaded to the extent of 60-600 N until fracture occurred. The fracture pattern of abutment screw and fixture was observed under scanning electron microscope. A comparative study of stress distribution and fracture area of abutment screw and fixture was carried out through finite element analysis Results: 1. In Vicker's hardness test of abutment screw, the highest value was measured in group A and lowest value was measured in group D. 2. In all implant groups, implant fixture fractures occurred mainly at the 3-4th fixture thread valley where tensile stress was concentrated. When the fatigue life was compared, significant difference was found between the group A, B, C and D (P<.05). 3. The fracture patterns of group B and group D showed complex failure type, a fracture behavior including transverse and longitudinal failure patterns in both fixture and abutment screw. In Group A and C, however, the transverse failure of fixture was only observed. 4. The finite element analysis infers that a fatigue crack started at the fixture surface. Conclusion: The maximum tensile stress was found in the implant fixture at the level of cortical bone. The fatigue fracture occurred when the dead space of implant fixture coincides with jig surface where the maximum tensile stress was generated. To increase implant durability, prevention of surrounding bone resorption is important. However, if the bone resorption progresses to the level of dead space, the frequency of implant fracture would increase. Thus, proper management is needed.

• The korean journal of orthodontics
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• v.27 no.1
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• pp.1-20
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• 1997

Skeletal Class III malocclusions are growth-related discrepancies, and the problems are more severe until growth is complete. Causes of skeletal Class III malocclusion are classified into mandibular overgrowth, maxillary deficiency, and combination of the two. Face mask has been recommended for treatment of Class III malocclusion with maxillary deficiency in the early time of growth. Numerous experiments were performed and clinical studies have been reported on face mask ; nevertheless, studies on profile changes and stability after treatment of face mask are considered to be somewhat insufficient. The author selected 50 patients who can be checked for follow-up. They had been diagnosed as skeletal Class III malocclusion with maxillary deficiency and then treated with face mask ; the sample group was divided according to sex, treatment beginning age, palatal suture opening (intraoral appliance). For each group, changing pattern of facial profile and stability of treatment observed, and comparison with 20 Korean normal children(Angle's Class I). The following results were obtained. 1. skeletal, dental, and soft tissue measurements indicated more changes in the amounts of maxillary forward movement during face mask treatment. 2. R.P.E. group showed more significant maxillofacial changes and La-Li group showed more dental changes. 3. Growth changes of maxilla induced in the treatment group during wearing face mask were much more than those of normal group. 4. Growth changes of maxilla in the treatment group after treatment of face mask were less than those of normal group. From the obtained aata, it can be concluded that there was a stimulative effect on forward growth of maxilla during the use of face mask ; however, on removal of face mask, the stimulative effect was eliminated and undergrowth tendency of maxilla resumed.

• The Korean Journal of Nuclear Medicine
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• v.39 no.1
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• pp.26-33
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• 2005

Purpose: The purpose of this study is to evaluate migration of technetium-99m hexamethylpropylene amine oxime ($^{99m}Tc$-HMPAO) labeled immature and mature dendritic cells (DC) in the mouse. Methods: DC were collected from bone marrow (BM) of tibiae and femurs of mice. Immature and mature DC from BM cells were radiolabeled with $^{99m}Tc$-HMPAO. To evaluate the functional and phenotypic changes of DC from radiolabeling, the allogeneic mixed lymphocyte reaction (MLR) and fluorescence-activated cell sorting (FACS) analysis were performed before and after labeling with $^{99m}Tc$-HMPAO. Migration of intravenously injected DC (iv-DC) was assessed by serial gamma camera images of mice with or without subcutaneous tumor. Percent injected dose per gram (%ID/g) was calculated in lungs, liver, spleen, kidneys, and tumor through dissection of each mice after 24 hours of injection. Results: Labeling efficiency of immature and mature DC were $60.4{\pm}5.4%\;and\;61.8{\pm}6.7%$, respectively. Iv-DC initially appeared in the lungs, then redistributed mainly to liver and spleen. Migration of mature DC to spleen was significantly higher than that of immature DC ($38.3{\pm}4.0%\;vs.\;32.2{\pm}4.1%$ in control group, $40.4{\pm}4.1%\;vs.\;35.9{\pm}3.8%$ in tumor group; p<0.05). Migration to tumor was also significantly higher in mature DC than in immature DC ($2.4{\pm}0.3%\;vs\;1.7{\pm}0.2%$; p=0.034). Conclusion: Assessment of migration pattern of DC in mice was possible using $^{99m}Tc$-HMPAO labeled immature and mature DC. Migration of mature DC to spleen and tumor was higher than that of immature DC when they were i.v. injected.

• (The)Study of the Eastern Classic
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• no.34
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• pp.63-88
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• 2009

This paper was a quest of pattern of holding "Dae Hak - the Great Learning" during Joseon Period having investigated the characteristics of the Essentials of the Studies of the Sages(聖學輯要, Seong Hak Jibyo) that was compiled by Lee I was a reinterpretation of the Great Learning, and also academic enrichment. During the period of Joseon Dynasty, the Great Learning had held the most important position as core scripture in the intellectual society that pursued Seong Hak(聖學, sage learning). Throughout the Joseon Period, the Great Learning was the essential text for the Emperorship Learning(帝王學, Jewang Hak) as well as Seong Hak, and it can also be said that Seong Hak Jibyo compiled by Yulgok - the courtesy name of Lee I, was the comprehensive collections thereof. While compiling Seong Hak Jibyo, Yulgok presented a model of Seong Hak of Joseon, which was based on "the Great Learning". Yul Gok organized the system of "Seong Hak Jibyo" largely in five parts, and properly arranged the Three Cardinal Principles(三綱領, samgangryeong) and Eight Articles or Steps(八條目, paljomok) therein. Particularly, in the Chapter Two, "Cultivating Oneself(修己, sugi)", Yulgok deal with 'being able to manifest one's bright virtue'(明明德, myeong myeong deok) among the Three Cardinal Principles as the core curriculum, meanwhile, Yulgok also covered "Investigation of things, gyeongmul(格物)," "Extension of knowledge, chiji(致知)," "Sincerity of the will, Seongui(誠意)," "Rectification of the mind, Jeongshim(正心)," "Cultivation of the personal life, susin(修身)," among Paljomok(eight steps) as the ultimate purpose of 'Stopping in perfect goodness'(止於至善, jieojiseon) These well preserve the principal system of Confucianism where "Cultivating oneself and regulating others (修己治人, sugichiin)" are core value, and his instructions as such also back up academic validity logically by presenting specific guidelines for practice according to each domain. Reinterpretation of "The Great Learning" by Yulgok in Seong Hak Jibyo is an arena to investigate the characteristics of Confucianism in Joseon Period, which was different from that of China, furthermore, such guidelines might take a role as criteria to understand the characteristics of humans and learning possessed by Korean people.

• Korean Journal of Environmental Agriculture
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• v.42 no.1
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• pp.35-43
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• 2023

The fine particulate structure of biochar limits its use as a heavy metal adsorbent, and makes separation of the biochar from the solution technically challenging, thereby reducing recovery of the heavy metals. To address this issue, this study prepared biochar beads under various mixing conditions and investigated their efficiency in removing Pb from aqueous solutions using adsorption models. The biochar beads were produced by mixing alginate and biochar at different ratios: alginate bead (AB), 1% biochar + bead (1-BB), 2.5% biochar + bead (2.5-BB), and 5% biochar + bead (5-BB). The results revealed that the Freundlich isothermal adsorption pattern of the biochar beads to Pb was of the L-type. The highest Langmuir isothermal adsorption capacity (28.736 mg/g) was observed in the 2.5-BB treatment. The dominant mechanism among the kinetic adsorption characteristics of biochar beads for Pb was chemical adsorption. Additionally, the optimal pH range for Pb adsorption was found to be between 4 and 5.5. The highest Pb removal efficiency (97.9%) was achieved when 26.6 g/L of biochar beads were used. These findings suggest that biochar beads are an economical and highly efficient adsorbent that enables separation and recovery of fine biochar particles.