• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.53-62
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• 2018

Follofwing the accelerating speed-up of trains and rising demand for large-volume transfer capacity, not only in Korea, but also around the world, track structures for trains have been improving consistently. Precast concrete slab track (PST), a concrete structure track, was developed as a system that can fulfil new safety and economic requirements for railroad traffic. The purpose of this study is to provide the information required for the development and design of the system in the future, by analyzing the behavior of each structural member of the PST system. The stress distribution result for different combinations of appropriate loads according to the KRL-2012 train load and KRC code was analyzed by conducting a three-dimensional finite element analysis, while the result for different thicknesses of the grouting layer is also presented. Among the structural members, the largest stress took place on the grouting layer. The stress changed sensitively following the thickness and the combination of loads. When compared with a case of applying only a vertical KRL-2012 load, the stress increased by 3.3 times and 14.1 times on a concrete panel and HSB, respectively, from the starting load and temperature load. When the thickness of the grouting layer increased from 20 mm to 80 mm, the stress generated on the concrete panel decreased by 4%, while the stress increased by 24% on the grouting layer. As for the cracking condition, tension cracking was caused locally on the grouting layer. Such a result indicates that more attention should be paid to the flexure and tension behavior from horizontal loads rather than from vertical loads when developing PST systems. In addition, the safety of each structural member must be ensured by maintaining the thickness of the grouting layer at 40 mm or more.

• Journal of the Korea Society of Computer and Information
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• v.6 no.4
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• pp.188-205
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• 2001

Insurer's duty of declaration is based on reciprocity of principle of the highest good, and recently it is widely recognized in the British and American insurance circles. The conception of fiduciary relationship is no longer equity or the legal theory which is only confined to the nations with Anglo-American laws. Therefore, recognizing the fiduciary relationship as the essence of insurance contract, which is more closely related to public interest than any other fields. will serve an efficient measure to seek fair and reasonable relationship with contractor, and provide legal foundation which permits contractor to bring an action for damage against violation of insurer's duty of declaration. In the future, only when the fiduciary relationship is approved as the essence of insurance contract, the business performance and quality of insurance industry is expected to increase. Therefore, to keep well this fiduciary relationship, or increase the fiduciary relationship persistency rates seems to be the bottom line in the insurance industry. In this paper, we developed a fiduciary relationship maintenance ratio based on comparison by case, which is represented with usually maintained contract months to paid months, based on each contract of the basis point. In this paper we have developed a new business model seeking the maximum profit with low cost and high efficiency, management policy of putting its priority on its substantiality, as an improvement measure to break away from the vicious circle of high cost and low efficiency, and management policy of putting its priority on its external growth(expansion of market share).

• Clinical and Experimental Reproductive Medicine
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• v.33 no.1
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• pp.25-33
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• 2006

Objective: The aim of this study was to investigate whether embryonic stem (ES) cells can be established from isolated blastomeres of mouse embryos. Methods: Blastomeres were separated from mouse (C57Bl/6J) 2- or 4-cell embryos. Isolated blastomeres or whole 4-cell embryos were co-cultured with mitosis-arrested STO feeder cells in DMEM supplemented with recombinant murine leukemia inhibitory factor and ES-qualified fetal bovine serum. After the tentative ES cell lines were maintained from isolated blastomeres or whole embryos, some of them were frozen and the others were sub-cultured continually. Characteristics of tentative ES cell lines as were evaluated for specific genes expressions with immunocytochemistry and RT-PCR. Results: One ES cell line (3.0%) was established from isolated blastomere of 2-cell embryo and one cell line (4.0%) from isolated two blastomeres of 4-cell embryo. And five cell lines (16.7%) were established from whole 4-cell embryos. Both cell lines from isolated blastomere and whole embryo expressed mouse ES cell specific markers such as SSEA-1, Oct-4 and alkaline phosphatase. Marker genes of three germ layers were expressed from embryoid bodies of both cell lines. Conclusion: This study suggests that mouse ES cells could be established from isolated blastomeres, although the efficiency is lower than whole embryos. This animal model could be applied to establishment of autologous human ES cells from biopsied blastomeres of preimplantation embryos in human IVF-ET program.

• Korean Journal of Materials Research
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• v.7 no.4
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• pp.347-353
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• 1997

BaTiO$_{3}$물질은 뛰어난 유전체로 널리 알려져 왔으며 특히 Heywang등이 제안한 PTCR특성은 이 물질의 응용범위를 세라믹 필터, 회로보호소자, 온도감지소자 및 저항가열장치 등으로 확대시켰다. 이러한 특성의 발현기구는 아직까지 밝혀지지 않은 상태이지만 제 특성을 향상시키기 위한 노력은 계속되어왔다. 특히 개발목적에 맞게 온도에 따른 정저항 특성(PTCR; Positive temperature constnat of resistivity phenomena)을 설계하려는 시도가 계속되어 왔으며 그 중에서도 페로브스카아트계의 2가와 4가의 양이온 자리를 등가나 원자가가 다른 양이온으로 치환하여 특성을 개선하려는 시도가 계속되어 왔다. 특히 $Ca^{2+}$나 Sr$^{2+}$는 $Ba^{2+}$자리를 치환할 수 있는 물질로 개별적인 첨가에 대한 연구는 많은 연구자들에 의해 진행된 상태이지만 최종적인 영향이나 해석에 대해서는 연구자들간에 이견이 많은 상태이다. 이번 실험에서는 BaTiO$_{3}$계에 합성한 (Ca, Sr)TiO$_{3}$를 Ca와 Sr의 상대적인 비를 변화시키면서 전체적인 첨가량을 변화시켜 그에 따른 전기적 특성 및 미세구조를 살펴보았다. (Ca, Sr)TiO$_{3}$의 첨가로 상온저항 및 PTCR특성을 변화시킬 수 있었으며 이를 통해 PTCR물질의 활용범위를 넓힐 수 있는 발판을 마련할 계기가 되었다. 특히 기존의 연구가 주로 개별적인 Ca나 Sr의 첨가에 의한 미세구조와 전기적 특성변화의 연구에 치중해 있었던 것과는 달리 Sr과 Ca을 함께 치환하여 상대적인 비가 특성에 더 중요한 영향을 끼치는 것을 확인하였으며 적절한 합성비를 선택하면 퀴리온도에서의 저항변화폭을 유지하면서 상온저항을 낮출 수 있음을 확인하였다.문했던 연구소인 Shanghai Research Center of Biotechnology, Shanghai Institute of Industrial Microbiology 및 Scientific Research Institute of Food and Fermentation Industry을 소개하고저 한다. 짧은 기간의 방문이라 주로 해당연구소의 자체소개 자료를 중심으로 방문하면서 느낀점을 기술하고저 한다.초염기성암 기원의 사문암이 열수변질작용을 받아 생성되었음을 명확하게 지시하며, 따라서 활석 광석내에 존재하는 녹니석은 활석의 근원 광물로서 녹니석편암 및 녹니석 편마암 매의 녹니석이 활석화되고 남은 잔존광물이 아니라, 주변암에 의해 성분상의 영향을 받은 열수와 사문암과의 변질교대작용에 의한 활석화과정 중에 주로 생성된 것으로 추정된다. 이러한 결과는 연구지역의 활석광상이 초염기성암의 사문암화 작용과 활석화 작용의 두 가지 변질작용에 의해 형성되어졌음을 알려준다.농도 증가 없이 폐 조직에 약 50배 정도의 고농도 cisplatin을 투여할 수 있었으며, 또한 분리 폐 관류 시 cisplatin에 의한 직접적 폐 독성은 발견되지 않았다이 낮았으나 통계학적 의의는 없었다[10.0%(4/40) : 8.2%(20/244), p>0.05]. 결론: 비디오흉강경술에서 재발을 낮추기 위해 수술시 폐야 전체를 관찰하여 존재하는 폐기포를 놓치지 않는 것이 중요하며, 폐기포를 확인하지 못한 경우와 이차성 자연기흉에 대해서는 흉막유착술에 더 세심한 주의가 필요하다는 것을 확인하였다. 비디오흉강경수술은 통증이 적고, 입원기간이 짧고, 사회로의 복귀가 빠르며, 고위험군에 적용할 수 있고, 무엇보다도 미용상의 이점이 크다는 면에서 자연기흉에 대해 유용한 치료방법임에는 틀림이 없으나 개흉술에 비해 재발율이 높고 비용이 비싸다는 문제가 제기되고 있는 만큼 더 세심한 주의와 장기 추적관찰이 필요하리라 사료된다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.9
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• pp.1333-1338
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• 2015

This study investigated the effects of addition of Chrysanthemum indicum L. extracts on quality characteristics of Kukhwju during fermentation. Fermented liquors without C. indicum L. were used as the control group. For experimental groups, we added 1, 2, 5, and 10% C. indicum L. extracts and brewed according to the addition method written in Yorok. The pH level during fermentation phase, alcohol concentration, level of reducing sugars, and acidity were measured in each of the experimental groups. After fermentation, we measured total contents of phenols, antioxidant effects, free sugars, organic acids, and chromaticity. During fermentation, no significant difference was observed between the C. indicum L. group and control group. Regarding total phenol contents and antioxidant effects, only the 5% and 10% C. indicum L. groups showed higher contents of phenols than the non-addition group. In general, 5% and 10% C. indicum L. addition groups were positively evaluated. In conclusion, Kukhwaju with 10% C. indicum L. extract showed the best antioxidant effects. In the present study, we obtained different characteristics and determined the optimum addition amount of C. indicum L.

• Food Science and Preservation
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• v.12 no.3
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• pp.282-286
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• 2005

This study was to investigate the content of total phenolic compounds, electron donating ability, nitrate-scavenging effect, and angiotensin converting enzyme(ACE) inhibition effect of medicinal plant liquors prepared from Cnidium officinale, Angelica gigas, Pueraria thunbergiana(root), Pueraria thunbergiana (flower), and Glycyrrhiza uralensis. Physicochemical characteristics of the medicinal plant liquors are as follows: pH $5.65{\sim}6.36$; reducing sugar, $0.13{\sim}0.45\%$. The highest value of total phenolic compounds was found in liquor prepared with Pueraria thunbergiana(root) as $23.9{\sim}54.3\;mg\%$. The electron donating ability of liquor prepared with Pueraria thunbergiana showed the highest value($67.4{\sim}85.3\%$) among the liquors, and its nitrite scavenging ability($24.56{\sim}78.3\%$) showed the highest value than those of other medicianal plant liquors. ACE inhibitory activity showed the highest value in liquor prepared with Cnidium officinale.

• Journal of Environmental Policy
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• v.5 no.1
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• pp.45-70
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• 2006

China has achieved great economic growth above 9% annual since it changed to more of a market economy system by its reform and open-door policy. At the same time, China has experienced severe ecological deterioration, such as air and water pollutions caused by its rapid urbanization and industrialization. China is now confronted with environmental pollution and ecological deterioration at a critical point, at which economic development in China is limited. Moreover, environmental problems in China have become a lit fuse for social fluctuation beyond pollution problems. The root and background of environmental problems in China, firstly, are its government's lack of understanding of these problems and incorrect economic policies affected by political and ideological prejudice. Secondly, the plundering of resources, 'the principle of development first' which didn't consider environmental sustainability is another source of environmental deterioration in China. In addition, a huge population and poverty in China have increased the difficulty in solving its environmental problems, and in fact have accelerated them. The Chinese government has established many environmental laws and institutions, increased environmental investments, and is enlarging the participation of NGOs and the general public in some limited scale to solve its environmental problems. However, it has not obtained effective results because of the lack of environmental investments owing to the government's limit of the development phase, a structural limit of law enforcement and local protectionism, and the limit of political independency in NGOs and the lack of public participation in China. It seems that China remains in the stage of 'economic development first, environmental protection second', contrary to its catch-phrase of 'the harmony between economic development and environmental protection'. China is now confronted with dual pressure both domestically and abroad because of deepening environmental problems. There are growing public's protests and demonstrations in China in response to the spread of damage owing to environmental pollution and ecological deterioration. On the other hand, international society, in particular neighboring countries, regard China as a principal cause of ecological disaster. In the face of this dual pressure, China is presently contemplating a 'recycling economy' that helps sustainable development through the structural reform of industries using too much energy and through more severe law enforcement than now. Therefore, it is desirable to promote regional cooperation more progressively and practically in the direction of building China's ability to solve environmental problems.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.110-122
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• 2009

Purpose: Nowadays, A medical institution assesment could get more interest about a quality of medical services from many hospitals that developed the active activities for improving medical services. Also, there is an other additional issue which is the patients risk management. Uijeongbu ST. Mary's hospital Nuclear Medicine department has been changed many work process after PET-CT introduction and renovation of its place since 2008. Therefore, modified structure and the way of existing work process have contained risk factors. The purpose of this study would be the appropriate risk management process while imaging examination process, the removal risk factors and improved activities through the analysis risk factors. Materials and Methods: Nuclear Medicine department new process should analysis through many-sided, Firstly, make and trained risk management manual after then apply an actual work. Result analysis showed the number of risk accident occurrence that comparing the last year and after the improved activities. Secondly, producing risk management public relations film has been showed an applicable patient after then the customer service measurement checked for a hundred patient by questionnaire. Lastly, Risk factors were eliminated through the facilities participation improving activities which could change for the better risk factors. Results: The number of safety accident occurrence(medication error, fall and collision) were checked as zero after the improving activities both PET-CT and gamma camera examination. The results of questionnaire showed as follows; 74% marked as understanding of the test process and 81% checked "satisfaction" after the public relations film showing. The question "Did you consider about the risk factors?", both PET-CT and gamma camera checked as 94% and 89% respectively. Customer risk management could be accomplished effectively through the improving activities at the nuclear medicine department. Conclusions: The study would be an opportunity that spread risk factors were systematically showed and analyzied. Also, It showed the possibility of the minimized safety accident and its feedback, if application of the response manuel that could be a standard of radiology technician's work method to react safety accident. It was the more effective that visual material could be easy to approach as a methodology of risk factors. As far as I have concerned that It could help the safety and convenience through continuous and detailed activities that offer to patients.

• Journal of the Korean earth science society
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• v.22 no.5
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• pp.360-376
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• 2001

This qualitative research investigated in-service science teachers' perceptions about cooperative learning and their perceived barriers in implementing cooperative learning in their classrooms. The underlying premise for cooperative learning is founded in constructivist epistemology. Cooperative learning (CL) is presented as an alternative frame to the current educational system which emphasizes content memorization and individual student performance through competition. An in-depth interview was conducted with 18 in-service science teachers who enrolled in the first-class teacher certification program during 2001 summer vacation. These secondary school teachers's interview data were analyzed and categorized into three areas: teachers' definition of cooperative learning, issues with implementing cooperative learning in classrooms, and teachers' and students' responses towards cooperative learning. Each of these areas are further subdivided into 10 themes: teachers' perceived meaning of cooperative learning, the importance of talk in learning, when to use cooperative learning, how to end a cooperative class, how to group students for cooperative learning, obstacles to implementing cooperative learning, students' reactions to cooperative learning, teachers' reasons for choosing (not choosing) student-centered approaches to learning/teaching, characteristics of teachers who use cooperative learning methods, and teachers' reasons for resisting cooperative learning. Detailed descriptions of the teachers' responses and discussion on each category are provided. For the development and implementation of CL in more classrooms, there should be changes and supports in the following five areas: (1) teachers have to examine their pedagogical beliefs toward constructivist perspectives, (2) teacher (re)education programs have to provide teachers with cooperative learning opportunities in methods courses, (3) students' understanding of their changed roles (4) supports in light of curriculum materials and instructional resources, (5) supports in terms of facilities and administrators. It's important to remember that cooperative learning is not a panacea for all instructional problems. It's only one way of teaching and learning, useful for specific kinds of teaching goals and especially relevant for classrooms with a wide mix of student academic skills. Suggestions for further research are also provided.

• Applied Biological Chemistry
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• v.45 no.1
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• pp.11-17
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• 2002

Fermentation characteristics with/without nitrogen source and quality of the fruit distillate of Opuntia ficus-indica var. saboten were investigated during the manufacturing process of a Korean traditional liquor. As the fermentation period increased, acidity, brix degree, and alcohol concentration increased, whereas pH and contents of reducing sugar decreased. Acidity, pH, and brix degree were higher, whereas the content of reducing sugar lower, in the nitrogen source-added distillate than in the distillate without nitrogen source. The growth of yeast increased, while that of bacteria decreased; this trend was more prominent with the addition of a nitrogen source. Sojues, distilled from two types of mashes and diluted with $H_2O$ and tails of distillate into 22% alcohol concentration, showed pH $3.7{\sim}4.0$, acidity $0.02{\sim}0.10$, and $5.4{\sim}6.1$ $^{\circ}Brix$. Analysis through GC using direct injection methods revealed common volatile flavor compounds in sojues, including acetaldehyde, acetyl acetone, acetic acid ethyl ester, ethyl alcohol, 2-propyl alcohol, acetone, n-propyl alcohol, butanoic acid methyl ester, 2-phenyl ethanol, thymol, acetic acid phenyl ester, and vanillic aldehyde. As revealed through the sensory evaluation, no significant difference (p>0.05) in overall acceptability was shown among four experimental groups, while color and flavor showed significant differences(p<0.05).