• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.589-594
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• 2006

The recycling of industrial wastes in the concrete manufacturing is of increasing interest worldwide, due to the high environmental impact of the cement and concrete industries and to the rising demand of infrastructures, both in industrialized and developing countries. The production of municipal wastes in the South Korea is estimated at about 49,902 ton per day and only 14.5% of these are incinerated and principally disposed of in landfill. These quantities will increase considerably with the growth of municipal waste production, the progressive closing of landfill, so the disposal of municipal solid waste incinerator(MSWI) ashes has become a continuous and significant issue facing society, both environmentally and economically. MSWI ash is the residue from waste combustion processes at temperature between $850^{\circ}C\;and\;1,000^{\circ}C$. And the main components of MSWI ash are $SiO_2,\;CaO\;and\;Al_2O_3$. The aim of this study is to find a way to useful application of MSWI ash(after treatment) as a structural material and to investigates the hydraulic activity, compressive strength development composition variation of such alkali-activated MSWI ashes concrete. And it was found that early cement hydration, followed by the breakdown and dissolving of the MSWI-ashes, enhanced the formation of calcium silicate hydrates(C-S-H). The XRD and SEM-EDS results indicate that, both the hydration degree and strength development are closely connected with a curing condition and a alkali-activator. Compressive strengths with values in the 40.5 MPa were obtained after curing the activated MSWI ashes with NaOH+water glass at $90^{\circ}C$.

• Survey Research
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• v.10 no.3
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• pp.59-83
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• 2009

The purpose of this study is to understand why female labor force participation rates decline in early times after their marriage. Data were derived from the 4th(2001) to 9th(2006) Korea Labor & Income Panel Study. 194 Korean married women in twenties and thirties who had a job before marriage were analyzed. Survival analysis was used to explore the first labor force exit of married women longitudinally. The major findings are as follows. First, nearly half of them went away from labor market in the first 3 years after marriage. Second, child birth was the most significant factor in predicting women's labor force exit. Married women's employment discontinuity tend to be lowered after child birth, with working hour decreasing, and with the number of available family-friendly policies increasing. Married women's income encouraged them to hold on their career, though husband's income and household income were not significant. Third, married women tended to leave their job before giving birth. Women who remained in the labor market at child birth or until a year after birth were inclined to continue their job thereafter. Fourth, maternity leave and childcare leave diminished the probability of employment discontinuity. Many working wives could not use a maternity leave or childcare leave. This study shows married women usually underwent labor market exit in their newly married time. They cannot help facing conflict between the role of mother's and a worker's. Family-friendly policies could encourage working wives to rear child and continue work at the same time. The findings of this study could serve as fundamental material for further studies and would be a key to find effective solution for problematic issues on reconciling work and family.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.5
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• pp.526-536
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• 2006

Statement of problem : Use of fiber composite technology as well as development of nonmetal implant prosthesis solved many problems due to metal alloy substructure such as corrosion. toxicity, difficult casting, expensiveness and esthetic limit. After clinical and laboratory test, we could find out that fiber-reinforced composite prostheses have good mechanical properties and FRC can make metal-free implant prostheses successful. Purpose : The purpose of this study is to evaluate the flexural strength of implant fixed prosthesis using fiber reinforced composite. Material and methods : 2-implant fixture were placed in second premolar and second molar area in edentulous mandibular model, and their abutments were placed, and bridge prostheses using gold, PFG, Tescera, and Targis Vectris were fabricated. Tescera was made in 5 different designs with different supplements. Group I was composed by 3 bars with diameter 1.0mm and 5 meshes, 2 bars and 5 meshes for Group II, 1 bar and 5 meshes for Group III, and only 5 meshes were used for Group IV. And Group V is composed by only 3 bars. Resin (Tescera) facing was made to buccal part of pontic of gold bridge. All of gold and PFG bridges were made on one model, 5 Targis Vectris bridges were also made on one model, and 25 Tescera bridges were. made on 3 models. Each bridge was attached to the test model by temporary cement and shallow depression was formed near central fossa of the bridge pontic to let 5 mm metal ball not move. Flexual strength was marked in graph by INSTRON. Results : The results of the study are as follows. The initial crack strength was the highest on PFG. and in order of gold bridge Tescera I, Tescera II, Targis vectris, Tescera IV, Tescera III, and Tescera V. The maximum strength was the highest on gold bridge, and in order of PFG, Tescera I, Tescera IV Tescera II, Targis vectris, Tescera III, and Tescera V. Conculsions : The following conclusions were drawn from the results of this study. 1. Flextural strength of implant prosthesis using fiber reinforced composite was higher than average posterior occlusal force. 2. In initial crack strength, Tescera I was stronger than Tescera V, and weaker than PFG. 3. Kinds and number of auxillary components had an effect on maximum strength, and maximum strength was increased as number of auxillary components increased. 4 Maximum strength of Tescera I was higher than Targis vectris, and lower than PFG.

• Hwankyungkyoyuk
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• v.4 no.1
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• pp.89-211
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• 1993

The Korean government embarked upon ambitious economic development plans in the 1960's the goals of development policy at that time were the elimination of absolute poverty and the alleviation of unemployment. With scant natural resources, the government had to push for industrialization based upon borrowed foreign raw materials with surplus local labor. Preoccupation with the economic goals of industrialization and export expansion left little room for considering environmental protection. It is evident that Korea's exported industrialization strategy of the past three decades has been a success in terms of income, production, and other macroeconomic indicators, but it cannot be denied that a host of undesirable side-effects have been created. These include environmental problems. congestion in several large cities, poor wealth distribution, and regional disparities. The environmental problems were recognized even in the early stage of development, but preoccupation with the pending economic goals of industrialization and export expansion left little room for considering environment protection. The perceived and actual seriousness of the problems, however, has reached such a level that further negligence may imperil political stability and developmental problems facing the world arise from a world economic order characterized by ever expanding consumption and production, which exhausts and contaminates natural resources and creates and perpetuates gross inequalities between and within nations. It will be necessary to develop new culture and ethical values, transform economic structures, and reorient, our lifestyles. Changing lifestyles can not be promoted by government policy initiative alone but through self=generated educational efforts and mutual training by people themselves. The citizens group for environment (NGOs) should assume these educational and training responsibilities starting from grass-root level of people. It must be reawakened to the reality that the environmental preservation for better quality of life is based on the development of human relationships, creativity, spirituality, reverance for the natural world and celebration of life, and is not dependent upon increased consumption of non-basic material goods. To carry on such environment education social movements and NGOs should (1) provides educational methodologies, which focus on values clarification and moving beyond clarification and moving beyond blame to constructive action. (2) provide training for leaders of business and industry, government, union and others on consumption and production. (3) initiate and support the training and work of environmental counselor who encourage responsible consumption. (4) cooperative with media to initiate and strengthen educational programs on the social environmental programs on the social environmental impacts of consumption and production and to build awareness of consumer responsibility and potential. Economic and social development can be compatible with environment protection : both can be achieved simultaneously. Effective environmental management depends on the various factors : political will, institutional arrangements, appropriate legislation, and availability of the requistite financial and technological resources, which is possible with a strong public awareness of the importance of environmental preservation.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.936-942
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• 2018

The diagnostic multi-leaf collimator preventing unnecessary dose from entering into patients during the diagnostic examination was made in this study. The movement of the entire 50 leaves was embodied with the group of 25 ones thereof configured in a pair facing each other on the left and right of the median line. Dimensions of the length, width, and height of each shielding leaf were $5{\times}0.5{\times}0.5cm^3$ resulting in the maximum boost field of $10{\times}10cm^2$. The material of multi-leaf collimator had the excellence on the machinability with the use of the SKD-11 alloy tool steel having the high wear resistance against frequent movement, and it was devised to control both-side's shielding leaves by moving 2 motors unlike existing remedial multi-leaf collimator that use as many motors as the number of 50 shielding leaves. Thereafter, the transmission dose of leaves, cross-leaf leakage dose, and inter-leaf leakage dose were measured by the developed multi-leaf collimator attached to X-ray equipment. An ionization chamber was used to detect doses there from, and the comparative analysis was carried out by means of the radiographic film that was easy to detect the dose leakage in between each leaf. Results obtained from the test conducted in comparative analysis yielded approximately 98%, 96%, and 94% of shielding efficiency realized at each level of energy of 80kV, 100kV, and 120kV it was confirmed there was no dose leakage resulted from the varied level of irradiation energy. Thus the multi-leaf collimator to be developed based on this study is thought that it could fully reduce the unnecessary dose to patients in the diagnostic test and the shielding efficiency thereof is expected to be increasing if it is made in a miniaturized form with a way of increasing the thickness of each leaf later for an extended application to general diagnostic purposes.

• Journal of Plant Biology
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• v.1 no.1
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• pp.11-20
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• 1958

I. Assumption: Mo-kam-ju, Koelreuteria paniculata is a woody plant mainly cistributed over Northern China. Its sporadic growth along the beaches of Korea and Japan is assumed to have been sowed by the seeds transported adrift on the current across the ocean. II. Use and Growth of the Plant: In China, this plant has been cultivated from early times mainly at temples, it seeds being used as rosaries, its flowers for yellow dyes and medicine for the eyes, and its leaves for black dyes. In Korea and Japan, these plants have been cultivated at temples and used as the material for rosaries. No natural growth of these plants was reported until 1919. III. Discoveries: In this domestic area, Dr. Chung Tae Hyun discovered the plant on the beach between Cho-Do and Chang-san-kot, Hwang-Hae Prov. in 1920. The reporter discovered them on the beach at Buk-Ni, Duk-jok-Do in 1948, at An-Hung in 1956 and on the beach at An-min-Do in 1957. In the Japan area, it was discovered for the first time twenty years ago, mainly along the coast line of the Japan Sea and some along the eastern coast line, at Subo, Yamaguchi Prefecture facing the Pacific Ocean. IV. Study and Experiment: A. Seed The seed coat is thick, non-permeable and floatable. A number of seeds were immersed in artificial sea water and fresh water separately. The seeds remained there for a hundred and forty-five (145) days from April 6, 1957 to August 29, 57. Thirty one seeds out of the fifty immersed in salt water and twenty seeds out of the fifty immersed in fresh water remained on the surface of the water, proving them to be non-permeable to both sea and fresh water. Of course, these had retained their germinating capabilities. Five (5) seeds out of twenty from the fresh water and six (6) out of thirty-one from the sea water were successfully germinated after a hole had been drilled in the seed coat and they had been planted. Thus their floating capability, non-permeability and germinating capability after a possible 145 day trip on the flowing currents has been proved satisfactory according to the assumption made above. B. Current As shown in the Data 2 and 3, the sea current initiated in the Pohai Sea flows westward down along the coast line of Korea reaching the southern part during the autumn and winter seasons. This fact also is in favor of the reporter's assumption. V. Discussion and Conclusion: The reporter concludes that, as discussed above, Koelreuteria paniculata which originates in Northern China is transported adrift on the flowing sea current to our western coast line, and also the coast lines of Shantung and Kuangtung of China and it is germinated on the sandy beaches forming new plants. Thus, the seeds drifted down on the southern beach of Korea and have been transported to the Japanese coast, adrift on the Tae-Ma current. Upon fruition, the seeds of the plants which settle on the coasts of western Korea and Japan will migrate to new places. It can be, however, assumed that while the thickness and nonpermeability of the coat enables the long travel in the water, this also can compose a difficulty in germination, consequently in developing a new distribution of this species.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.2
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• pp.72-78
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• 2020

Demand for cosmetics with functionality and eco-friendliness has increased dramatically due to recent aging, well-being trends, and increased interest in beauty. Cosmetics production in 2014 was 8,970.4 billion won, an increase of about 50% compared to 6,014.6 billion won in 2010. In the midst of this, similar companies in intense competition are pursuing differentiated strategies and innovation activities to solve quality, price and delivery problems. In particular, cosmetics packaging work is getting more difficult due to the increasing bill of materials (BOM) and difficult assembly methods. Therefore, in this study, the following problems were identified and suggestions for the improvement of the packaging Many research laboratories such as biotechnology, chemistry, and pharmaceuticals, which are undergoing various studies, are equipped with ready-made laboratory safety equipments such as bio-safety workbenches, aseptic bases, and exhaust workbenches. However, most researchers are disadvantaged in using existing safety equipment. This is because existing safety equipment can not take into account all of the unique characteristics of the research. For this reason, researchers are demanding the development of customized safety equipment that is well suited to their research needs. process of Company C, which is facing difficult situation to respond to the customer 's delivery due to the 52 - hour work week. First, we used the stopwatch to find the difficulty process in the packaging process and show ways to improve it. Second, to improve the efficiency of line balancing in the packaging process, we integrate processes, improve work methods, and perform simple automation. As a result, the prepare loss for replacement was reduced by 1 minute from 5 minutes, resulting in a 23% increase in productivity from 112 ea./hour to 137ea./ hour per person. At this time, the LOB of the packaging process was improved from 70% to 82% by operating one more production line through one person per line, total 9 people saving.

• Korean Journal of Legislative Studies
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• v.23 no.1
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• pp.187-226
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• 2017

North Korea discourse is doubtful. A considerable portion is distorted under political objectives, group identity, and interests. Surely, there are facts based on North Korea's conducts. Apparent deceptions commonly exist as well though. Korean media does not endeavor to set the records straight and there are no revision towards mislead information. This is substantially dangerous as it can misjudge North Korean policies, beget national antipathy, and interferes with rational and constructive policy making. This study stems from such concerns and takes such cases as HEU(Highly Enriched Uranium) suspicion of 2002, dispute covering BDA(Banco Delta Asia)'s counterfeiting, and the abandonment of the Geneva Agreed Framework into consideration. The first part concentrates on fathoming the truth of the three cases. References from US government, academia, think tanks, media were inquired with an addition of secondary material from Korea and China. Secondly it examines whether domestic news properly reflects the precedent facts along the process of discovery. The cause and solution suggested by domestic media were organized and inductively reconstituted to frames. The last study questions the structural factors that reproduces suspicion analogs. Today's dangers facing Korean society are essentially not natural but artificial. This research hopes to foster peace by analyzing related discourses that are infamous to reinterpret reality.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.213-220
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• 2023

Mixed-matrix membranes (MMMs), which are composed of a polymer matrix filled with high-performance fillers as a dispersed phase, have been intensively studied for gas separations for the past 30 years. It has been demonstrated that MMMs exhibit superior gas separation performance compared to polymer membranes and are more scalable than polycrystalline membranes. Despite their potential, the commercialization of MMMs has yet to be reported due to several challenging issues. One of the major challenges of MMMs is the non-ideal interface between the continuous polymer phase and dispersed phase, which can result in defect formation (i.e., interfacial voids, etc.). With respect, many MMM studies have focused on addressing the issues through scientific approaches. The engineering approaches for facile and effective large-scale fabrication of MMMs, however, have been relatively underestimated. In this review paper, a novel strategy for fabricating MMMs in a facile and scalable manner using in situ metal-organic framework (MOF) formation is introduced. This new MMM fabrication methodology can effectively address the issues facing current MMMs, likely facilitating the commercialization of MMMs.

• Journal of Science of Art and Design
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• v.11
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• pp.221-249
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• 2007

Today, photography is facing to the crisis of identity and dilemma of ontology from the digital imaging process in the new technology form. It is very important points to say rethinking of the traditional photographic medium, that has changed the way we view the world and ourselves is perhaps an understatement and that photography has transformed our essential understanding of reality. Now, no longer are photographic images regarded as the true automatic recording, innocent evidence and the mirror to the reality. Rather, photography constructs the world for our entertainment, helping to create the comforting illusions by which we live. The recognition that photographs are not constructions and reflections of reality, is the basis for the actual presence within the contemporary photographic world. It is shock. This thesis's aim is to look for the problems of photographic identity and ontological crisis that is controlling and regulating digital photographic imagery, allowing the reproduction of the electronic simulations era. Photography loses its special aesthetic status and becomes no more true information and, exclusively evidence by traditional film and paper that appeared both as a technological accuracy and as a medium-specific aesthetic. The result, photography is facing two crises, one is the photographic ontology(the introduction of computerized digital images) and the other is photographic epistemology(having to do broader changes in ethics, knowledge and culture). Taken together, these crises apparently threaten us with the death of photography, with the 'end' of photography and the culture it sustains. The thesis's meaning is to look into the dilemma of photography's ontology and epistemology, especially, automatical index and digital codes from its origin, meaning, and identity as the technological medium. Thus, in particular, thesis focuses on the analog imagery presence, from the nature in the material world, and the digital imagery presence from the cultural situations in our society. And also thesis's aim is to examine the main issues of the history of photography has been concentrated on the ontological arguments since the discovery of photography in 1839. Photography has never been only one static technology form. Rather, its nearly two centuries of technological development have been marked by numerous, competing of technological innovation and self revolution from the dual aspects. This thesis examines recent account of photography by the analysis of the medium's concept, meaning, identity between film base image and digital base image from the aspects of photographic ontology and epistemology. Thus, the structure of thesis is fairy straightforward to examine what appear to be two opposing view of photographic conditions and ontological situations. Thesis' view contrasts that figure out the value of photography according to its fundamental characteristic as a medium. Also, it seeks a possible solution to the dilemma of photographic ontology through the medium's origin from the early years of the nineteenth century to the raising questions about the different meaning(analog/digital) of photography, now. Finally, this thesis emphasizes and concludes that the photographic ontological crisis reflects to the paradoxical dynamic structure, that unsolved the origins of the medium, itself. Moreover, even photography is not single identity of the photographic ontology, and also can not be understood as having a static identity or singular status from the dynamic field of technologies, practices, and images.