• Membrane Journal
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• v.27 no.4
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• pp.367-373
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• 2017

Pressurized membrane module systems, including hollow fiber type of Microfiltration (MF) and Ultrafiltration (UF) membranes are being increasingly used in drinking water treatment due to their high removal efficiency of pathogen. However, when fibers are damaged in pressurized membrane system, the pathogen will be able to penetrate the membrane. Therefore, it is essential to guarantee the regulatory requirements for water quality by an effective on-line or off-line condition integrity monitoring methods. Recently, pressure decay test (PDT) which is one of membrane integrity tests has been reflected to drinking water treatment plants using pressurized membrane module. In this paper, three different method were used to perform PDT and three different sensitivity values were analyzed through experiments. Three types of direct integrity test methods were applied to pressure feed side, filtrate side and bidirectional pressure decay test. The results of these experiments show that the sensitivity was increasing when the volume of pressurized gas was decreasing. The sensitivity is inversely proportional to the gas volume. Furthermore, it is desirable to increase pressure difference between feed side and permeate side in order to achieve higher sensitivity in the PDT by membrane damage.

• Journal of Agricultural Extension & Community Development
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• v.21 no.3
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• pp.243-269
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• 2014

Traditional agriculture technology is absolutely valuable not only to preserve biological diversity but construct an eco-friendly agricultural system. As the awareness of food safety has been growing, traditional technologies in the past agriculture literatures have obtained more attention sine chemical or synthesized fertilizer and agricultural pesticide were not used in these traditional agriculture ways. This study aims to evaluate development values on six kinds of agriculture literatures published before initial 1970s using Delphi technique and Correspondence analysis. The domains of assesment are include livestock sanitation, breeding management, feeding program and an extra part which 261 traditional agriculture technologies were first extracted from. From these technologies, livestock experts deducted 228 items and selected items more than 3.0 from all three areas including usefulness, scientific characteristic and economical efficiency utilizing Delphi technique.: 35 items from usefulness, 31 items from scientific characteristic, and 18 items from economical efficiency. The 23 technology items were finalized after adding five modern feasibility items recommended by experts to 18 items gaining more than 3.0 in at least three areas. The agriculture technologies were categorized into four areas where were analyzed using Correspondence analysis. The results revealed that 'sustainable farming technology', 'scientific character verification', ' modernized technology development', and 'intellectual property right' were placed closely one another except 'economy efficiency'. The result implicated that scientific verification and economy efficiency should be considered in order to sustain traditional agriculture technology into a modernized way and to protect intellectual property right of these technologies.

• Journal of Korea Port Economic Association
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• v.26 no.3
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• pp.42-55
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• 2010

This paper primarily deals with a decision-making for determining the number of voyages in each ship size under a specific port structure in order to minimize the total transport cost consisting of transport cost at sea, queuing cost in port, and inventory cost in yard. As a result of computer simulation using queuing model characterized by inter-arrival time distribution, we were able to find out some combination of voyage numbers of 3 ship-size(50,000-ton, 100,000-ton, and 200,000-ton), where the total transport cost can be minimized under a specific port structure. The simulation model also allows us to figure out any trade-off relationship among sea transport cost, queuing cost in port, and inventory cost in yard. Put it differently, an attempt to reduce the sea transport cost by increasing the number of voyages of the largest ship size, the transport cost incurred in both port and yard is hypothesized to be increased and vice versa. Consequently, Port managers are required to adjust the number of annual number of voyages allocated in each ship size, put into the sea lines for importing raw materials, in order to optimize the transport costs incurred under the specific port system. We may consider a net present value(NPV) model for performing an economic feasibility analysis on port investment project. If a total discounted net benefit, including cost savings, exceeds the initial investment for an additional berth construction, then we accept the port investment project. Otherwise, we reject the proposed port investment plan.

• Clean Technology
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• v.19 no.3
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• pp.313-319
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• 2013

To produce biodiesel efficiently from fish oil containing 4% free fatty acid, esterification and trans-esterification were carried out with Vietnam catfish oil, which was kindly provided from GS-bio company. Heterogeneous solid acid catalysts such as Amberlyst-15 and Amberlyst BD-20 and sulfuric acid as homogeneous acid catalyst were used for the esterification of free fatty acids in the fish oil. Sulfuric acid showed the highest removal efficiency of free fatty acid and the shortest reaction time among three acid catalysts. The base catalysts for trans-esterification such as KOH, $NaOCH_3$ and NaOH were compared with each other and KOH was determined to be the best transesterification catalyst. Some solid material, which assumed to be saponified product from glycerol and biodiesel, were observed to form in the fish oil biodiesel when using $NaOCH_3$ and NaOH as the transesterification catalyst. The initial acid value of fish oil was proven to have a negative effect on biodiesel conversion. Of the three catalysts, KOH catalyst transesterification was shown to have high content of FAME and the optimal ratio of methanol/oil ratio was identified to be 9:1.

• Korean Journal of Crystallography
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• v.12 no.2
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• pp.70-75
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• 2001

The purpose of this study is to investigate the effect of V₂O/sub 5/ addition on physical and magnetic properties of NiCuZn ferrite for multi-layer chip inductors. NiCuZn ferrite pastes doped with 0, 0.1, 0.3 and 0.5 wt% V₂O/sub 5/ were prepared and samples of ferrite sheets were prepared by the screen printing method. They were sintered at 870, 880, 890 and 900℃, and then their physical and magnetic properties were analyzed. After sintering at 870℃, the sintered density of the ferrite sheet doped with 0.5wt% V₂O/sub 5/ showed the highest value to 5.08g/cm³due to the best densification by the liquid phase sintering, while the microstructures of ferrite sheets doped with 0.1 and 0.3 wt% V₂O/sub 5/ showed and inhibited grain growth. Irrespective of the sintering temperature, the initial permeability of ferrite sheet doped with 0.5 wt% V₂O/sub 5/ was highest and after sintering beyond 880℃, the quality factor of 0.3 wt% V₂O/sub 5/-doped sample appeared to be highest.

• The Journal of Advanced Prosthodontics
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• v.3 no.2
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• pp.57-62
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• 2011

MATERIALS AND METHODS. Ceramics have a long history in fixed prosthodontics for achieving optimal esthetics and various materials have been used to improve ceramic core strength. However, there is a lack of information on how color is affected by fabrication procedure. The purpose of this study was to evaluate the effects of various dentin ceramic thicknesses and repeated firings on the color of zirconium oxide all-ceramic system (LavaTM) fabricated using CAD/CAM technology. MATERIALS AND METHODS. Thirty disc-shaped cores, 12 mm in diameter with a 1 mm thickness were fabricated from zirconium oxide based all ceramic systems ($Lava^{TM}$, 3M ESPE, St Paul, MN, USA) and divided into three groups (n = 10) according to veneering with dentin ceramic thicknesses: as 0.5, 1, or 1.5 mm. Repeated firings (3, 5, 7, or 9) were performed, and the color of the specimens was compared with the color after the initial firing. Color differences among ceramic specimens were measured using a spectrophotometer (VITA Easyshade, VITA Zahnfabrik, Bad $S{\ddot{a}}ckingen$, Germany) and data were expressed in CIELAB system coordinates. A repeated measures ANOVA and Bonferroni post hoc test were used to analyze the data (n = 10, ${\alpha}=.05$). RESULTS. $L^{\ast}a^{\ast}b^{\ast}$ values of the ceramic systems were affected by the number of firings (3, 5, 7, or 9 firings) (P<.001) and ceramic thickness (0.5, 1, or 1.5 mm) (P<.001). Significant interactions were present in $L^{\ast}a^{\ast}b^{\ast}$ values between the number of firings and ceramic thickness (P<.001). An increase in number of firings resulted in significant increase in $L^{\ast}$ values for both 0.5 mm and 1.5 mm thicknesses (P<.01, P=.013); however it decreased for 1 mm thickness (P<.01). The $a^{\ast}$ values increased for 1 mm and 1.5 mm thicknesses (P<.01), while it decreased for 0.5 mm specimens. The $b^{\ast}$ values increased significantly for all thicknesses (P<.01, P=.022). As the dentin ceramic thickness increased, significant reductions in $L^{\ast}$ values (P<.01) were recorded. There were significant increases in both $a^{\ast}$ and $b^{\ast}$ values (P<.01) as the dentin ceramic thickness increased. CONCLUSION. The number of firings and dentin ceramic thickness have a definite effect on the final color of all ceramic system tested. The mean ${\Delta}E$ value increased as the dentin ceramic thicknesses increased for zirconium-oxide based all ceramic specimens tested. However, the mean ${\Delta}E$ values were less than 3.7${\Delta}E$ units which is rated as a match in the oral environment.

• Journal of The Korean Association For Science Education
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• v.32 no.5
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• pp.789-804
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• 2012

We developed $21^{st}$ century scientific literacy assessment instrument and applied it to explore the contents of seven Korean science textbooks. The $21^{st}$ century scientific literacy assessment instrument involved three dimensions (habits of mind, character and values, science as human endeavor). Each dimension consists of three sub-dimensions. Five science education experts assessed the content of textbook using criteria. We discussed issues in which the examiners responses did not match and reached an agreement on initial disagreement. As a result, we found that most Korean textbook contained contents on habits of mind, especially, communication, collaboration, and information management. We also found that most materials lacked information about character and values and science as human endeavor. Based on the result, we suggest that researchers and science educators need to consider all dimensions of the $21^{st}$ century scientific literacy when they develop curriculum and teaching materials. In addition, the rubric for $21^{st}$ century scientific literacy can be adopted as an assessment tool for examining curriculum, teaching materials.

• Korean Journal of Social Welfare
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• v.63 no.2
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• pp.319-336
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• 2011

There is recent recognition that the approach toward family members is crucial for understanding problems in multi-cultural families by emerging from typical approach focused on migrant women. While researches have reported serious conflicts and adaptation problems from cultural difference between parent-in-law and foreign daughter-in-law, cultural stress of parent-in-law has not been systematically examined. The purpose of this study was to develop and validate a scale to measure acculturation stress of parent-in-law who have a foreign daughter-in-law. The sample consisted of 266 parents-in-law from three provinces of South Korea. Initially, 16 items were generated based on the existing scale of acculturation stress and they are tested by item-analysis through the descriptive and correlational analysis. An exploratory factor analysis was conducted to investigate the factor structure of the scale and a confirmatory factor analysis was used to validate the scale. By item-analysis, five items were deleted from initial scale items because of redundancy. Findings from an exploratory factor analysis provided the evidence that the scale consists of three factors which are the perception of prejudice and discrimination, conflicts from different cultural value, and daily discomfort. Cronbach's ${\alpha}$ for the scale is 0.86. Multiple fit indices from confirmatory factor analysis indicated that the hypothesized three-factor model for acculturation stress achieved a good fit with the data. Results showed the evidence for the reliability and validity of the scale for acculturation stress of the parent-in-law who have foreign daughter-in-law. The scale would have potential effects for assessing psychological stress for parent-in-law in research and clinical practice. Further implications and limitation of the study and suggestions for future studies were discussed.

• The Journal of the Korean dental association
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• v.54 no.7
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• pp.521-528
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• 2016

Purpose: The aim of this study was to evaluate the erosive potential of several fruit-flavored liquors marketed in Korea by measuring pH, titratable acidity, and variations in pH utilizing an ISO method. Materials and Methods: Six fruit-flavored liquors were investigated. An orange juice and three kinds of soju were selected as the control beverage. The pH and titratable acidity of the beverages were determined by 1 M NaOH until the pH 5.5 and 7.0 (recorded as $TA_{5.5}$ and $TA_{7.0}$, respectively). All measurements were performed in triplicate. The process of ISO 28888 was used for measurement of the pH variation (${\Delta}pH$) using an under-saturated hydroxyapatite solution (screening solution) and determining the difference between the initial and final pH of the screening solution. The average ${\Delta}pH$ was determined based on 4 measurements. Results: All the fruit-flavored liquors tested in this study showed a pH lower than the critical pH for dental erosion (4.5). The average pH of the fruit-flavored liquors was 2.77 and was also lower than the pH of the soju and an orange juice (control drinks). $TA_{5.5}$ and $TA_{7.0}$ values of the fruit-flavored liquors were 4.92ml and 7.13ml, respectively. The fruit-flavored liquors showed an erosive potential capable of damaging the enamel surfaces, whereas the orange juice had the highest titratable acidity. The changes in pH determined using the screening solution confirmed that the fruit-flavored liquors had erosive potential, with ${\Delta}pH$ value of 1.53. Conclusions: The fruit-flavored liquors tested in this study might have a strong potential to erode dental hard tissues.

• Journal of Korean Academy of Nursing
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• v.15 no.3
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• pp.5-20
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• 1985

The purpose of this study was to assess the value-of post-operative treatment in terms of nursing care in the allevation of pain. More specifically, the effects of supportive touch and patient education were examined. On the date before each patient's operation, the Bevels of anxiety, depression and affiliation were examined. The post-operative treatment was adminis. tered after an initial measurement of the patient's fain, according to the experimental category for the three days following the operation. On the final day, the level of anxiety and depression were again measured. The subjects of this study were 138 patient from the general surgical and gynecological wards in H university Hospital in Seoul. The study was conducted over a three-month period from June 24, 1984 to September 18, 1984. All patients had undergone laparatomies. Various standard instruments were used to measure the pain, anxiety, depression and affiliation levels. for pain, 5 grate Simple Descriptive Scale, and the Mclachlan four-range Observational Pain Scale were employed. For anxiety and depression, respectively the Spielberger State Anxiety Inventory and Beck Depression Inventory (B.D.I.) were used. Lastly, the affiliation was determined by the Mehrabian Affiliation Scale. The outcome of the research was as follows: 1. The first hypothesis concerning the existence of lower pain levels of Experimental Group A and Experimental Group B than the pain levels of Control Croup C was not supported. 2. The second hypothesis concerning the existence if lower anxiety levels of Experimental Group A and Experimental Group B than the anxiety levels of Control Group C was supported at the level of F=3.58 (p=.03). 3. The third hypothesis concerning the existence of lower depression levels of Experimental Group A and Experimental Group B than the depression levels of Control Group C was not supported. 4. The fourth hypothesis concerning the existence of different levels of pain in accordance with the levels of affiliation in Experimental Group A was not supported. 5. A positive correlation did exist between pain and anxiety after surgery (r=.34, p=.0001). Thus, the fifth hypothesis was supported. 6. A positive correlation did exist between pain and depression following surgery(r=.36, p=.0001). Thus, the sixth hypothesis was supported. Based on the above results, it was found that supportive touch and patient education either through human sources or via tape recorder do influence the anxiety of a patient after surgery, that a Positive correlation between pain, anxiety and deparession exist, that affiliation does not alter the influence of supportive touch, and that the graph on which pain levels were depicted indicates the possibility of development even if the effects of supportive touch did not reach a meaningful level. Thus it can be concluded that patient education, regardless of its form, is essential for the patient after surgery and that supportive touch, when reasonably modified and supplemented, can be an effective method of alleviating pain.