• Analytical Science and Technology
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• v.18 no.6
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• pp.511-519
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• 2005

A method for determination of toluene diisocyanates (TDI) in toluene diisocynate (TDI)-based polyurethane (PUR) packing material was investigated, and also the migration of TDI to food was studied. TDI was extracted using food simulants such as n-haptane and 4% aqueous acetic acid. The determinations were performed using gas chromatography/mass spectrometry (GC/MS). One of major components for polyurethane, toluene diisocyanates, were detected in ten samples among twenty six food contact materials with the concentration range of $0.51{\sim}60.88{\mu}g/ml$. However the highest extracted amount was just 0.7% of $60.88{\mu}g/ml$ if the contact surface of food packing for extracting liquid was limited to the outer layer without exposure of the cutting edge of food packing multi-layers. The result of this study and the analysis method for TDI diisocyanate will be very useful for further study about food contact material, and the monitoring result could be used for evaluating the safety of food contact material before it is to be used for food, preservation.

• Korean Journal of Digital Imaging in Medicine
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• v.13 no.1
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• pp.13-20
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• 2011

Now a days in our society, occupation boundaries have become blurred, and come into the limelight in the prior occupation or miss about new workplace. Medical area is no exception also, So we face urgent problem about protecting and spreading RT work-sphere simultaneously. This research allow to identify on RT role area of digital environment that is obscure profession-realm specially, and open up a new field hereafter. We examined present RT role area of digital environment in the more than thirty medical facility(general or university hospital) through questionnaire/visit survey from PACS administrator. Survey sentence comprises total 29 sentence over all main quadrisection-(eX. hospital formation & treatment state and PACS team composition & organization and PACS team workplace and PACS team daily workload), We performed comparative analysis in general contents perspectively. further more, divided main 5 section based on upper analysis and then manufactured output in consideration of each medical facility's operation state. There are comparative problem of hospital policy, So we maintained information security of each facility exhaustively. First, we separated a survey output into main 5 section as follows-(eX. PACS server & maintenance manage, Client/interlock manage, PACS data conversion, 3D reconstruction, PACS data im/export)-that received by 35 medical facility. And then manufactured output with comparative analysis about RT role area each section, general IT managing team about medical environment was out of existence that fill up with RT manpower in the surveyed medical facility consequently. What is worse, hospitals that entirely fill up with another worker were 3 place amazingly. Our specific statistic results show, the respondents was 63% that agree with reorganization of formation base on independence team, and supplement of the personnel average -continuous with upper agreement simply-was about 2.64. Further more, if reorganization break out with only RT manpower, quota TO will increase by geometric progression. Protecting and spreading role workplace is much accounted of the our inevitable project surely and more than 95% PACS administrator's have confidence in this proposition unconditionally. Henceforth, look forward to meeting the RT vision of many-sided multiplayer, based on acquire a specialized IT knowledge actively and open up a new work-field with frontier spirit.

• Polymer(Korea)
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• v.35 no.3
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• pp.189-195
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• 2011

The design of new bioactive scaffolds offering physiologic environment for tissue formation is an important frontier in biomaterials research. In this study, we performed compressive strength, water-uptake ability, and SEM analysis for physical property assessment of 3-D silk/PLGA scaffold, and investigated the adhesion, proliferation, phenotype maintenance, and inflammatory responses of RAW 264.7 and NIH/3T3 for cell compatibility. Scaffolds were prepared by the solvent casting/salt leaching method and their compressive strength and water-uptake ability were excellent at 20 wt% silk content. Result of cell compatibility assay showed that inflammatory responses distinctly decreased, and initial adhesion and proliferation were maximized at 20 wt% silk content. In conclusion, we suggest that silk/PLGA scaffolds may be useful to tissue engineering applications.

• (The)Study of the Eastern Classic
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• no.62
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• pp.209-229
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• 2016

This thesis is to discover the meanings of boundary through East Asian thought so as to make rooms for discoursing on it. First of all people have their own boundaries of 'Me', and they make others as persons or objects in their thoughts. Originally boundary has represented nation's frontier, and it indicated the worlds of space in Buddhism of East Asian culture. It is represented by loka or visaya in Sanskrit and region, dominion, boundary, border in English, which means the worlds that people would fancy in their minds over domains of politics, societies, culture, arts ect, not to be simple. Accordingly we must not approach to its meaning simply like 'beyond border'. There are many boundaries, which are similar to the sublime, for us to arrive in our lives. Spiritually there are also many boundaries(regions) that are made by our desires, wills and concepts. In a while there are limit or problem in our recognizing things, for example, of human's five senses that would be, to an extent connected with Buddhistic understanding of boundaries. Boundaries resulted from partiality in understanding of objects must be got rid of eventually. In regard of these matters, this thesis discusses the meanings of boundary, those that are inevitably made by human's consciousness, and negative ones to be got over from recognition systems of person or any groups.

• Cross-Cultural Studies
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• v.44
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• pp.373-391
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• 2016

Since the 2000's, interest toward Africa in Korea has increased rapidly. Korea's interest in Africa began in the second half of the 1960's. However, this interest in the 1960's was motivated by political and diplomatic necessity at the time rather than the needs of indigenous groups in Africa. Korea had to oppose North Korea's diplomatic expansion in Africa to gain the support of international organizations like the United Nations. This interest in Africa motivated by diplomatic needs vanished quickly after the end of the cold war in the 1990's. Authentic Korean interest in Africa began to emerge in the 2000's. Korea's rising international status based on economic development led to a natural interest in Africa, which was the last frontier on earth. As a result, African studies in Korea increased significantly after 2010. The increase in the number of theses, articles and books was remarkable from 2010-2016, in comparison with 1957-2010. In spite of the increase in the quantity of thesis, articles, and books, the problem with Korea's African studies is above all, its preponderance. Over 75% of thesis and 70% of articles are concentrated in the domain of politics and economics. This reflects the fact that Korea's interest in Africa is based on short term political and economic interest, indicating that Korea's African studies did not deviate from the rudimentary phase in its quantity and quality. Another problem with Korea's African studies is the lack of integration of different types of research. African studies in Korea has three components, government funded research centers, university laboratories and individual researchers. The government funded research centers focus on the overview of African nations and their political and economic information. University laboratories mainly perform research on the theoretical aspects of politics, economics, human sciences and culture in Africa. Individual researchers are concerned with various categories. However, these three groups have failed to achieve a synergic effect on African studies in Korea and most of the research on Africa does not extend beyond each academic area. To overcome this problem, first of all, a live exchange may be necessary between domestic researchers.

• Journal of Korea Port Economic Association
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• v.25 no.2
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• pp.57-72
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• 2009

The purpose of this paper is to show the empirical measurement way of operation risk evaluation in domestic seaports for overcoming the limitations which the traditional DEA method has by using 13 Korean ports in 2003 for 4 inputs(birthing capacity, cargo handling capacity, number of coastal guard vessel, number o f coastal special guard vessel ) and 5 outputs(Export and Import Quantity, Number of Ship Calls, number of coastal accident, number of coastal crime, number of coastal pollution). Because traditional DEA method has produced the limited set of information, negative DEA mixed with tier, stratification and layering methods should be adopted. The goal of negative DEA is to set up DEA models that will place the poor operating ports on or close to the empirical frontier. The core empirical results of this paper are as follows. First, Donghae ports should benchmark the operation way of Yeasu, Busan, Woolsan ports in terms of the middle and longterm base. Second, 5 ports(ports of Taean, Yeasu, Tongyoung, Busan, Sokcho) which were revealed as the poor operating ports in Negative DEA analysis should benchmark Incheon, Woolsan, Pohan, and Donhae ports. The policy implication to the Korean seaports and planners is that Korean seaports should introduce the new methods like Negative DEA of this paper for predicting the poor operating in the ports.

• Journal of Radiation Protection and Research
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• v.46 no.1
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• pp.14-23
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• 2021

Background: For radiological protection and control, the International Commission on Radiological Protection (ICRP) provides the nominal risk coefficients related to radiation exposure, which can be extrapolated using the excess relative risk and excess absolute risk obtained from the Life Span Study of atomic bomb survivors in Hiroshima and Nagasaki with the dose and dose-rate effectiveness factor (DDREF). Materials and Methods: Since it is impossible to directly estimate the radiation risk at doses less than approximately 100 mSv only from epidemiological knowledge and data, support from radiation biology is absolutely imperative, and thus, several national and international bodies have advocated the importance of bridging knowledge between biology and epidemiology. Because of the accident at the Tokyo Electric Power Company (TEPCO)'s Fukushima Daiichi Nuclear Power Station in 2011, the exposure of the public to radiation has become a major concern and it was considered that the estimation of radiation risk should be more realistic to cope with the prevailing radiation exposure situation. Results and Discussion: To discuss the issues from wide aspects related to radiological protection, and to realize bridging knowledge between biology and epidemiology, we have established a research group to develop low-dose and low-dose-rate radiation risk estimation methodology, with the permission of the Japan Health Physics Society. Conclusion: The aim of the research group was to clarify the current situation and issues related to the risk estimation of low-dose and low-dose-rate radiation exposure from the viewpoints of different research fields, such as epidemiology, biology, modeling, and dosimetry, to identify a future strategy and roadmap to elucidate a more realistic estimation of risk against low-dose and low-dose-rate radiation exposure.

• Computers and Concrete
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• v.31 no.3
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• pp.267-276
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• 2023

The main purpose of the current research is to develop an efficient two variables trigonometric shear deformation beam theory to investigate the buckling behavior of symmetric and non-symmetric functionally graded carbon nanotubes reinforced composite (FG-CNTRC) beam resting on an elastic foundation with various boundary conditions. The proposed theory obviates the use to shear correction factors as it satisfies the parabolic variation of through-thickness shear stress distribution. The composite beam is made of a polymeric matrix reinforced by aligned and distributed single-walled carbon nanotubes (SWCNTs) with different patterns of reinforcement. The material properties of the FG-CNTRC beam are estimated by using the rule of mixture. The governing equilibrium equations are solved by using new analytical solutions based on the Galerkin method. The robustness and accuracy of the proposed analytical model are demonstrated by comparing its results with those available by other researchers in the existing literature. Moreover, a comprehensive parametric study is presented and discussed in detail to show the effects of CNTs volume fraction, distribution patterns of CNTs, boundary conditions, length-to-thickness ratio, and spring constant factors on the buckling response of FG-CNTRC beam. Some new referential results are reported for the first time, which will serve as a benchmark for future research.

• Korea Trade Review
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• v.43 no.3
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• pp.1-26
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• 2018

This study estimates the technical efficiency and total factor productivity(TFP) of and analyzes the relationship between TFP and exports for Korean manufacturing companies from 2000 to 2016. Specially, TFP is decomposed into Technical Change(TC), Technical Efficiency Change (TEC), and Sale Effect(SE), and compared between large and small enterprises. First, in the case of technical efficiency, the Korean economy has been very vulnerable to external shocks, such as the sharp decline following the 2008 financial crisis. The efficiency of the electronics, automobile, and machinery sectors is low and needs to be improved. In addition, the technological efficiency of large enterprises is higher than that of SMEs in most manufacturing sub-sectors except for non-ferrous metals. In the case of TFP, most changes are due to TC, and the effective combination of labor, capital and the effect of scale have little effect, suggesting that improvement of internal structure is urgent. In addition, volatility due to the impact of the financial crisis in 2008 was much larger in SMEs than in large companies, so external economic impacts are more greater for SMEs than large enterprises. The relationship between TFP decomposition factors and exports shows that TC has a positive effect only on exports of SMEs. Therefore, in order to increase exports, in the case of SMEs, R&D support to promote technological development is needed. In the case of large companies, it is necessary to establish differentiated strategies for each export market, competitor company, and item to link efficiency and scale effect of exports.

• Journal of Korean Society of Disaster and Security
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• v.16 no.3
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• pp.27-34
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• 2023

In Korea, safety inspections of bridges are conducted periodically in accordance with law. Bridges are classified according to type, length, etdc., and the content and frequency of safety inspections are different. Bridges safety evaluation is performed on relatively large bridges, and safety evaluation of small bridges, which account for the majority of all bridges, is not mandatory. Therefore, in this study, in order to confirm the safety of small-scale bridges, a correlation analysis study was conducted with the common load carrying rate for each safety evaluation indicator. For this purpose, inspection reports of bridges from local goverments were collected, and the values for each bridges for about 50 indicators in the report were converted into data. By performing cleaning on the collected data and analyzing the correlation with the common load carrying rate, the top indicators related to safety for each bridges type were derived.