• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.54-61
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• 2000

Amalgam, though a widely used dental material, does not bond to the tooth substrate Therefore, retentive preparation of the cavity is necessary. Such amalgam restorations, until corrosion products form and plug the margin, will show significant marginal leakage. Unless this is prevented early on, saliva and bacteria may enter the cavity causing postoperative hypersensitivity, dissolution and collapse of the restoration, discoloration of the margin and secondary caries, leading to shortened life-span of the restoration and pulpal pathosis. Recently, a method of restoration has been introduced whereby tooth material can be preserved, cavity margin can be sealed and preventive treatment of pit and fissure can be administered while retaining all the advantages of conventional amalgam restorations. Such sealed amalgams involve removing the carious lesion without extending the cavity for prevention and using pit and fissure sealants to seal cavity margins and pit and fissures to reduce microleakage. In this study, finishing of the amalgam and sealant application were performed after different intervals following of amalgam restoration to compare the microleakage of sealed and conventional amalgam restorations. Thirty bicuspids were prepared with Class V cavity preparations on the buccal and lingual surfaces. After amalgam placement, they were divided into the following groups and treated accordingly. Group 1 : Polishing after 24 hours Group 2 : Immediate sealant application without polishing Group 3 : No polishing, but sealant applied after thermocycling 500 times After treatment, the samples were thermocycled 500 times between $5^{\circ}C$ and $55^{\circ}C$ with a dwell time of 30 seconds. After thermocycling, the samples were dipped into 1% methylene blue kept in a $37^{\circ}C$ incubator at 100% humidity for 24 hours. The teeth were then embedded in resin and cut bucco-lingually along the tooth axis and observed with a stereomicroscope to determine the degree of microleakage, The following results were obtained : 1. Group 2 showed the least microleakeage, while group 1 showed the greatest. 2. Group 1 showed significantly greater microleakage compared to group 2 (p<0.05). However, no significant differences were found between group 1 and 3(p>0.05). No significant differences in microleakage were also found between cup 2 and 3(p<0.05).

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1230-1236
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• 2012

To verify that the electrokinetic remediation is effective for decreasing salinity of fields of the plastic-film house, field tests for physical property, chemical property, and crop productivity of soils have been conducted. The abridged result of those tests is as follows. In the EK treatment, the electrokinetic remediation has been treated at the constant voltage (about 0.8 V $cm^{-1}$) for fields of the farm household. At this time, an alternating current (AC) 220 V of the farm household was transformed a direct current. The HSCI (High Silicon Cast Iron) that the length of the stick for a cation is 20cm, and the Fe Plate for an anion have been spread out on the ground. As the PVC pipe that is 10 cm in diameter was laid in the bottom of soils, cations descend on the cathode were discharged together. For soil physical properties according to the EK treatment, the destruction effect of soil aggregate was large, and the infiltration rate of water was increased. However, variations of bulk density and porosity were not considerable. Meanwhile, in chemical properties of soils, principal ions of such as EC, $NO_3{^-}$-N, $K^+$, and $Na^+$ were better rapidly reduced in the EK treated control plot than in the untreated control plot. And properties such as pH, $P_2O_5$ and $Ca^{2+}$ had a small impact on the EK. For cropping season of crop cultivation according to the EK treatment, decreasing rates of chemical properties of soils were as follows; $NO_3{^-}$-N 78.3% > $K^+$ 72.3% > EC 71.6% $$\geq_-$$ $Na^+$ 71.5% > $Mg^{2+}$ 36.8%. As results of comparing the experimental plot that EK was treated before crop cultivation with it that EK was treated during crop cultivation, the decreasing effect of chemical properties was higher in the case that EK was treated during crop cultivation. After the EK treatment, treatment effects were distinct for $NO_3{^-}$-N and EC that a decrease of nutrients is clear. However, because the lasting effect of decreasing salinity were not distinct for the single EK treatment, fertilization for soil testing was desirable carrying on testing for chemical properties of soils after EK treatments more than two times. In the growth of cabbages according to the EK treatment, the rate of yield increase was 225.5% for the primary treatment, 181.0% for the secondary treatment, and 124.2% for third treatment compared with the untreated control plot. The yield was increased by a factor of 130.0% for the hot pepper at the primary treatment (Apr. 2011), 248.1% for the lettuce at the secondary treatment (Nov.2011), and 125.4% for the young radish at the third treatment (Jul. 2012). In conclusion, the effect of yield increase was accepted officially for all announced crops.

• Journal of Korean Society of Forest Science
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• v.28 no.1
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• pp.50-66
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• 1975

Since it is an undeniable fact that the so-called illegal field-burning cultivation is directly implicated in the causes of forest devastation, land erosion, and drought and flood, thus, barring the nation from a well-balanced economic growth, the policy to exterminate its practices must have the topmost priority. Eighty percent of Gangweon-do is mountain forests and naturally of all others this province has the largest area of illegally burned hill-side farminglands, stubbornly retarding the provincial development policy as well as directly causing tremendous forest damages. In 1965 a 7-year plan mapped out to rehabilitate these gypsy type field burning farmers only to be suspended in 1968 to give way to the mandatory project of clearing the isolated farmsteads set in deep mountain to circumvent the guerilla forces signaled by the so-called Samcheok-Uljin area infiltration. In the meantime, new hordes of roving farmers burned the forests, working a renewed havoc. To cope with this situation, the provincial government, taking the year 1973 as a planning year, launched another three year project (1974-76) and has been enforcing the rehabilitation project mobilizing the whole administrative power. Whether or not this project will succeed solely depends upon whether the forcedly rehabilitated roving farmers can really establish self-supporting homesteads. Among the various difficulties facing the newly established homesteaders are: (1) First of all, the homesteaders must be given money-earning jobs. (2) Financial supports or subsidies must be provided them with which to establish self-supporting homesteads. (3) Private enterprises as well as public organizations must offer them jobs with priority. (4) The rehabilitated rovers themselves must establish self-supporting homesteads before expecting the external assistance. (5) The rehabilitated rovers themselves must have the spirit of self-help, welcoming all levels and all kinds of jobs. (6) The rural revitalization movement must expand the self-help reconstruction projects to give them the opportunity to work. (7) All citizen in the province must receive and protect them with brethren love. (8) The evacuated burned-forests must be reforestrated with the principle of "best trees to the best lands". (9) The seedlings of species that the forest owners select must anyhow be secured and supplied (10) The organization and function of the village forestry association must be strengthened to take effective care of the reforestated burned-forests.

• The Journal of the Korean bone and joint tumor society
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• v.16 no.1
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• pp.27-36
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• 2010

Purpose: Pigmented villonodular synovitis (PVNS) is a rare soft tissue tumor, which usually arises in larger joints, such as the knee. It has a high recurrence rate after surgical treatment. The purpose of this study is to evaluate and analyze the clinical results of diffuse-type pigmented villonodular synovitis cases that were treated with open total synovectomy. Materials and Methods: Between 1994 and 2006, 21 patients who had diffuse-type pigmented villonodular synovitis were selectively reviewed. Among the 21 cases studied, 14 patients presented at the knee, 5 at the ankle, and 2 at the shoulder and elbow. The mean follow up period was 5.5 years (range, 36-157 months). The average age of the patients was 34 years consist of 7 men and 14 women. Clinical outcomes were analyzed retrospectively, including range of motion and complications. Results: Open total synovectomy and adjuvant electrocautrization were done in all cases except one. During the regular follow-up period after the surgery, two patients showed symptoms of recurrence. After re-operation, only one case was pathologically confirmed as a recurrence. The patient who had partial synovectomy and the other patient who had second operation due to recur rence received additional radiation therapy. Clinical outcome scores were improved in every aspect (p<0.0001). 2 out of 14 Patients who had pigmented villonodular synovitis at the knee developed stiff knee after the surgery. Conclusion: After the open total synovectomy with electrocautrization, a low recurrence rate and satisfactory clinical outcome was achieved, observed in a minimum of 3 years of follow-up.

• Food Science and Preservation
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• v.11 no.2
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• pp.195-200
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• 2004

Microbial lethal value and nutrient retention of sous vide processed spinach were evaluated with mathematical model prediction and experimental trial for different package sizes and pasteurization temperatures. The package size covers 500 g, 1 kg and 2 kg, while the pasteurization temperature includes 80, 90 and 97$^{\circ}C$. The basic process scheme consists of filling blanched spinach into barrier plastic film pouch, sealing under vacuum, pasteurization in hot water with over pressure and final cooling to 3$^{\circ}C$. Pasteurization condition was designed based on attainment of 6 decimal inactivation of Listeria monocytogenes at geometric center of the pouch package by heating cycle, which was determined by general method. Heat penetration property of the package and thermal destruction kinetics were combined to estimate the retention of ascorbic acid and chlorophyll. Smaller packages with shorter pasteurization time gave better nutrient retention, physical and chemical qualities. Larger package size was estimated and confirmed experimentally to give higher pasteurization value at center, lower ascorbic acid and chlorophyll contents caused by longer heat process time. Lower pasteurization temperature with longer process time was predicted to give lower pasteurization value at center and lower ascorbic acid, while chlorophyll content was affected little by the temperature. Experimental trial showed better retention of ascorbic acid and chlorophyll for smaller package and higher pasteurization temperature with shorter heating time. The beneficial effect of smaller package and higher pasteurization temperature was also observed in texture, color retention and drip production.

• Journal of Plant Biotechnology
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• v.45 no.4
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• pp.400-408
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• 2018

Biodiversity has continued to degrade in the $21^{st}$ century due to global warming occasioned by destruction of the environment around the world.. The Nagoya protocol places Korea in a unique position to effectively develop and protect its domestic genetic resources. Microalgae under study in this research contains large amount of antioxidant substances such as beta carotene and astaxanthin, that can be used as biological resource owing to the large amounts of biomass that can be secured through photosynthesis. However, it is difficult to preserve it since cryopreservation method used for long-term preservation is yet to be developed. A basic study for long term cryopreservation was carried out on Nizschia frustulum and Nitzschia amabilis which belong to marine diatoms. As cryoprotectants (CPAs), glycerol, DMSO, and methanol which penetrate into cells were prepared at 5%, 10%, and 15% concentrations each, in case of methanol, it was tested at concentrations of 5%, 10% and 12% by its nature. Two kinds of microalgae, N. frustulum and N. amabilis, were diluted with $10^2$, $10^3$ and $10^4cells\;ml^{-1}$, respectively. The highest survival rate was shown at12% concentration of methanol, and the figures were $6.94{\pm}0.31%$ in N. frustulum and $8.85{\pm}0.16%$ in N. amabilis. As a result of 3 weeks cultivation of thawed microalgae after freezing, the result is shows that N. frustulum increased about 10 times faster and N. amabilis increased about 12 times the original concentration.

• Journal of Christian Education in Korea
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• v.64
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• pp.51-79
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• 2020

This study was conducted to pursue Christian education with the socially underprivileged in the era of the Corona-19 pandemic. Corona-19 is a disaster which is caused, destroyed and exploited by human being. At the time of the indiscriminately spreading global pendemic, we must work together to overcome our selfish self-centeredness and make an attempt for everyone in need. It is a study on how humans can help each other survive in the era of Corona-19 and its post-corona. The problem is that there is too much discrimination between the state, race, and economic capacity, and in the end, the extreme discrimination of capitalism is appeared in society and across the country. There is no significant difference in the confirmation rate when Corona-19 infiltrates, but there is a big difference between those with and less in mortality. As a result, today's reality is that people who have a hard time living because they have less usually are far more vulnerable to blocking and defeating virus attacks. Unfortunately, this is the current situation. From the standpoint of a large discourse, attention is paid to climate change and ecological environment, and as a micro discourse, a number of societies who live with tremendous discrimination according to the gap between the rich and the poor (it is gender, race, disabled, nationality) that exist in almost all countries on the planet. We need attention to the weak. To this end, discourses on vaccine inequality, discourses on the needs of the disabled, discourses on different racial damages, discourses on polarization and dystopia, and discourses on educational inequality were treated as the reality faced by the socially underprivileged in the Corona 19 pandemic. To explore Christian education with the socially underprivileged, to explore ways of sharing, giving, and solidarity for win-win, discourse on inter-dependence and mutual responsibility of mankind, direct counter-measures for the socially underprivileged, and critical literacy education. He proposed a discourse on Korea, a discourse on Homo sapiens, which must return to being a part of creation, and finally a theology of friendship with the weak. Christian education based on Bible words must go forward in the era of the Corona 19 pandemic, hungry, naked, nowhere to go, sick, but dying because of being unable to get a remedy. He emphasized the need to establish a caring theology of friendship and pursue a life in which thought and practice harmonize. Thus, the paper proposed the spirit of Christian education not only doing something for the socially weak, but with the socially weak in the daily life.

• Journal of Popular Narrative
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• v.27 no.3
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• pp.95-124
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• 2021

As the symbolic images of girls besides its definition have varied according to the age and society, a posthuman girl character recently appears in the digital cinema. This study aims to analyze its cinematic representations and the social contexts in which they are created. For this purpose, the study focuses on what extent the society allows its imagined figurations as a future female body and the meanings revolving around the image of 'technologically body-enhanced female fighter'. Current digital visualization technology has developed to the extent any imaged future humans can be represented, but posthuman girls' representations have its limitation that only a human-like figuration can be allowed in accord with the traditionally idolized image of girls. It is because of the representation logic in which digital cinema is visualized based on perceptual realism that values audiences' experiences. Despite such less critical figuration which does not dare to cross the boundary between the image of human and inhuman, the posthuman girl characters create a new category of the 'dangerous girls' who are both void of sexual femininity and independent of motherhood and heterosexual romance narrative. Of course, they support the modern human-centered belief that humans can take entire control of technology with their moral behaviors and dispel the fear about the negative impact the nature of technology may have on society at large by showing their child-like figuration protecting ethical values. However, the new character of 'unruly girl' exerts her subversive act that seeks to fight against the human-centered liberal humanistic values and melancholic feeling and vulnerability that the neoliberalism and technocracy enforce. When posthuman girl characters are considered to be a marker through which we can see how different social forces are intervening and competing each other in the upcoming posthuman age, the limited figuration of the posthuman girl characters in South Korean movies illustrates the opinionated thoughts toward the instrumentalism in technology but their bloodshed struggles reveal how the corporate or state-governed techno-biopower has oppressively treated and appropriated the human body as the technology-object and also provide a meaningful opportunity to rethink its unethical violence.

• Journal of Korea Water Resources Association
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• v.55 no.8
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• pp.603-611
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• 2022

In urban areas, the impermeable area continues to increase due to urbanization, which interferes with the surface penetrating and infiltrating of rainwater, causing most rainwater runoff to the surface, deepening the distortion of water circulation. Distortion of water circulation affects not only flood disasters caused by rainfall and runoff, but also various aspects such as dry stream phenomenon, deterioration of water quality, and destruction of ecosystem balance, and the Ministry of Environment strongly recommends the use of Low Impact development (LID) techniques. In order to apply the LID technique, it is necessary to set a rainwater management target to handle the increase in outflow after the development of the target site, and the current standard sets the rainwater management target using the 10-year daily rainfall. In this study, the difference from the current standards was analyzed through statistical analysis and classification of independent rainfall ideas using inter-event time definition (IETD) in setting the target amount of rainwater management to improve water circulation. Using 30-year rainfall data from 1991 to 2020, methods such as autocorrelation coefficient (AC) analysis, variation coefficient (VC) analysis, and annual average number of rainfall event (NRE) analysis were applied, and IETD was selected according to the target rainfall period. The more samples the population had, the more IETD tended to increase. In addition, by analyzing the duration and time distribution of independent rainfall according to the IETD, a plan was proposed to calculate the standard design rainfall according to the rainwater management target amount. Therefore, it is expected that it will be possible to set an improved rainwater management target amount if sufficient samples of independent rainfall ideas are used through the selection of IETD as in this study.