• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1999.04a
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• pp.5-5
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• 1999

The Principal deficiency of the existing notion about the sintering-mixtures consists in the fact that almost no attention is focused on the Phenomenon of alloy formation during sintering, its connection with dimensional changes of powder bodies, and no correct ideas on the driving force for the sintering process in the stage of establishing chemical equilibrium in a system are available as well. Another disadvantage of the classical sintering theory is an erroneous conception on the dissolution mechanism of solid in liquid. The two-particle model widely used in the literature to describe the sintering phenomenon in solid state disregards the nature of the neighbouring surrounding particles, the presence of pores between them, and the rise of so called arch effect. In this presentation, new basic scientific principles of the driving forces for the sintering process of a two-component powder body, of a diffusion mechanism of the interaction between solid and liquid phases, of stresses and deformation arising in the diffusion zone have been developed. The major driving force for sintering the mixture from components capable of forming solid solutions and intermetallic compounds is attributed to the alloy formation rather than the reduction of the free surface area until the chemical equilibrium is achieved in a system. The lecture considers a multiparticle model of the mixed powder-body and the nature of its volume changes during solid-state and liquid-phase sintering. It explains the discovered S-and V-type concentration dependencies of the change in the compact volume during solid-state sintering. It is supposed in the literature that the dissolution of solid in liquid is realised due to the removal of atoms from the surface of the solid phase into the melt and then their diffusicn transfer from the solid-liquid interface into the bulk of liquid. It has been shown in our experimental studies that the mechanism of the interaction between two components, one of them being liquid, consist in diffusion of the solvent atoms from the liquid into the solid phase until the concentration of solid solutions or an intermetallic compound in the surface layer enables them to pass into the liquid by means of melting. The lecture discusses peculimities of liquid phase formation in systems with intermediate compounds and the role of the liquid phase in bringing about the exothermic effect. At the frist stage of liquid phase sintering the diffusion of atoms from the melt into the solid causes the powder body to grow. At the second stage the diminution of particles in size as a result of their dissolution in the liquid draws their centres closer to each other and makes the compact to shrink Analytical equations were derived to describe quantitatively the porosity and volume changes of compacts as a result of alloy formation during liquid phase sinteIing. Selection criteria for an additive, its concentration and the temperature regime of sintering to control the density the structure of sintered alloys are given.

• Journal of Science Education
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• v.36 no.1
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• pp.84-93
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• 2012

We have studied possibilities of Peer Instruction(PI) to train in-service science teachers in elementary and middle schools through both degree of conceptual changes and investigating responses to questionaries. 169 teachers were attended and the subject for training was about light propagation to teach scientific conception about a pin hole camera. 6 conceptests were developed. Degree of conceptual changes was analyzed from results obtained from 24 elementary and 32 middle school teachers among them. On the other hand, answers to questionaries were obtained from 135. Relatively high gain near to about 0.7 in conceptual changes was obtained even though their initial levels were quite low. Interesting point is that elementary teachers have higher initial level and larger gain than middle school teachers. Teachers have very much enjoyed and showed strong support to PI for helping conceptual change, and willing to use PI to their own class. Also they conceived dealing concept in teacher training is very important and evaluated PI very positively for teacher training.

• Korean Journal of Psychosomatic Medicine
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• v.5 no.1
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• pp.3-11
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• 1997

In becoming parents, the marital partners enter into a new developmental phase. The conception of the child is an act of mutual creativity during which the boundaries between the self and another were temporarily obliterated more completely than at any time since infancy. The infant is a physical fusion of the parents, and their personalities unite within the child. for many women, creativity as a mother becomes a central matter that provides meaning and balance to their lives. The husband usually has strong desires for an offspring and can be transformed by it. The child can profoundly affect one or both parents, and the influences are reciprocal-a child's needs or specific difficulties uncover a parent's inadequacy. following the child's development, each transition into a new developmental phase requires an adaptation by the parents, and one or another of these required adaptations may disturb a parent's equilibirium. And the personality changes, emotional difficulties, and regressions of a spouse that occur in response to some phase of parenthood can upset the marriage. Not only do children identify with parents, but parents also identify with their children. The parents take pleasure in child's joy and suffer with the child's pain more than in almost any other relationship. certain respects e parents lives again in the child. Through the process of identification the child can also provide one of the two parents with the opportunity to experience intimately the way in which a person of the opposite gender grows up. Parenthood also provides the opportunity to be loved, admired, and needed simply because one is a parent and, as such, a central and necessary object in the young child's life. The many potentialities for emotional satisfactions from parenthood manage to outweigh the tribulations and sacrifices that are required. The child also exerts an indirect effect through changing the parent's position in the society, for new sets of relationships are established as the parents are drawn to other couples with children of the same age, and for a new impetus toward economic and social mobility often possesses the parents. frequently the couple's relatedness to their own parents improves and grows firmer once again. Parenthood, the satisfactions it provides and the demands it makes, varies as life progresses : and changes with the parent's interests, needs, and age as well as with the children's maturation. There are phases in the child's life that the parents are reluctant to have pass, whereas they tolerate others largely through knowing that they will soon be over. The changing lives of the children provide many satisfactions that offset the tribulations, uncertainties, and regrets. The parents change. The young father, who was just starting on his carrier whom the first child was born, settles into a life pattern. He becomes secure with increasing achievement and interacts differently with the youngest child and provides a different model for him than for the oldest. The mother may have less time for a second or third child than for her first, but she may also be more assured in her handling of them. The birth of a baby when the parents art in their late thirties will find them Less capable of physical exertion with the child and less tolerant of annoyances, but they are less apt to be annoyed. Eventually the children min and leave home, but the couple do not cease to be parents.

• Journal of The Korean Association For Science Education
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• v.18 no.4
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• pp.473-483
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• 1998

A learner's cognitive conflict with his /her existing conception is regarded to be one of the most important factors for a conceptual change. In this study, the effects of the conflict situation types on inducing students' cognitive conflicts in Newton's law were examined. The thirty-four students of 10th grade were selected from a rural high school based on the result of pre-test. The two different types of conflict situations among many possible types were used in this study. One type was using logical conflict situation and the other was demonstrating real conflict situation. The levels of cognitive conflict were measured by 4-point Likert scale by three interviewers. As the results, the demonstration method was more effective than the logical argument method. In case of the logical argument method, rather than showing scientific conceptions, suggesting another misconception was more effective to the students who have misconception. However, logical argument method was not effective to those who have scientfic conceptions. To the students who have unscientific conceptions, the demonstration method was very effective for inducing cognitive conflict. From the results of this study, demonstration method of teaching seems to be very effective for inducing students' cognitive conflict and overcoming their misconceptions on scientific concept.

• Journal of The Korean Association For Science Education
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• v.36 no.3
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• pp.423-434
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• 2016

The purpose of this study is to investigate preservice earth science teachers' mental models through applications of Coriolis force experiment apparatus. After the root of preconception was examined by face to face interviews based on the questionnaire, five preservice earth science teachers were finally selected for this study. The mental models about concept of Coriolis force was classified into naive mental model, static unstable mental model, dynamic unstable mental model, and scientific mental model through the result of individual interviews and their drawings. According to the mental model analysis about Coriolis' force conception, students C and M showed naive mental model about concept of Coriolis force before experiment. After the experiment, student M's model changed to static unstable mental model. Student C's model improved to dynamic unstable mental model. In adiition, students D and O's model improved from static unstable mental model to dynamic unstable mental model. In the case of student B, the dynamic unstable mental model was maintained after the experiment, however, student B's preconception changed to scientific concept. It turned out that a change occurred from low mental model level to integrated mental model after the application of the developed Coriolis' force experiment apparatus. According to the results, national curriculum is similar to static unstable mental model and the result of developed Coriolis' force experiment apparatus is similar to dynamic unstable mental model. It is suggested that it become the theoretical foundation to develop more comfortable and advanced Coriolis force experiment apparatus by improving the experiment apparatus.

• Journal of the Korean Chemical Society
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• v.56 no.3
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• pp.363-370
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• 2012

The purpose of the study was to classify scientific models in the seventh grade science textbooks of the 2007 revised science curriculum. The three chapters of 'three states of material', 'motion of molecule', and 'change of state and energy' were investigated. There were two types of the scientific model as 'mode of representation' and 'attribute of representation'. The mode of representation was composed of 'action model', 'analogical model', 'symbolic model', and 'theoretical model' and the attribute of representation was composed of 'static model' and 'dynamic model'. The results showed that the action model and the analogical model were used primarily in mode of representation. The dynamic model were widely used in attribute of representation. Area of matters dealt with conception of molecules and aimed for students to understand the arrangement and movement of molecule microscopically about macroscopic state in a daily life. Tis study could help to recognize the limitations of scientific models on current textbooks and offer more useful information in planning lessons and organizing textbooks for the future.

• Korean Journal of Optics and Photonics
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• v.19 no.5
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• pp.349-359
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• 2008

For an inner-focusing 3-groups zoom lens system, this study suggests a new initial design method which applies the process that changes thin lenses into thick ones effectively and quickly, using the hybrid lens system(thin lens+thick lens). In other words, the hybrid lens system is the semi-automatic design process that makes the thin lens of one group change into a thick one while the other groups are composed of thin lenses. Keeping the total power of the system fixed, the power of each group and the distance between principal planes can be fixed. Of course, the other groups composed of thin lenses could be changed into thick lenses sequentially by this process. This design conception results in the 1/4" 5 M inner-focusing 3-groups 2x zoom lens system satisfying the specifications and performances of zoom lens for phone cameras. Also aspherization on lens elements of glass and plastic material enhanced the resolution and reduced the lens size. As a result, we have an ultra-compact inner-focusing 3-groups 2x zoom lens system for a phone camera, with a slim size with TTL of 9.8 mm.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.289-297
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• 2021

Animation is a media reflecting social ideas, not only conveying information but also creating a new discourse. The purpose of this paper is to examine the social issues and gender discourse reflected in the media by analyzing the gender discourse inherent in the protagonist and surrounding characters, narrative characteristics, and background of the Ghibli animation "The Tale of the Princess Kaguya". As a research method for this purpose, figure out social problems related to gender performance, and analyze prior researches to derive a connection with the gender discourse in the animation. Grandfather is symbolic of a father who forces his daughter to follow his chosen happiness, and grandmother represents a mother who can not stop her husband. Stemaru is the character not in the original, posing a question of the problem of gender performance while failing to get married due to lack of sufficient wealth and honor. Princess Kaguya had been self-reliant and active like a modern woman at the beginning of the story. However, after being suppressed by society and people around her, the stereotyped gender performance forced Kaguya, who longed for the earth, to wish to return to the moon. Such social pressure happens in modern society. Gender performance is a systemic problem to be solved with systemic change. For this reason, constant consideration such as this paper is needed.

• Journal of Ginseng Research
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• v.43 no.4
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• pp.676-683
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• 2019

Background: Korean Red Ginseng (KRG) is widely used for strengthening the immune system and fighting fatigue, especially in people with deficiency syndrome. However, there is concern that the long-term application or a high dose of KRG can cause "fireness" (上火 in Chinese) because of its "dryness" (燥性 in Chinese). The aim of this study was to assess the safety and efficacy of a 4-week treatment with KRG in participants with deficiency syndrome. Methods: This was a 4-week, randomized, double-blind, placebo-controlled clinical trial. A total of 180 Chinese participants were randomly allocated to three groups: placebo control group, participants were given a placebo, 3.6 g/d; KRG 1.8 g and 3.6 g groups. The primary outcomes were the changes in fireness and safety evaluation (adverse events, laboratory tests, and electrocardiogram). The secondary outcomes were the efficacy of KRG on fatigue, which include the following: traditional Chinese medicine (TCM) symptom scale and fatigue self-assessment scale. Results: Of the 180 patients, 174 completed the full study. After 4 weeks of KRG treatment, the Fire-heat symptoms score including Excess fire-heat score and Deficient fire-heat score showed no significant change as compared with placebo treatment, and no clinically significant changes in any safety parameter were observed. Based on the TCM syndrome score and fatigue self-assessment score, TCM symptoms and fatigue were greatly improved after treatment with KRG, which showed a dose- and time-dependent effect. The total effective rate was also significantly increased in the KRG groups. Conclusion: Our study revealed that KRG has a potent antifatigue effect without significant adverse effects in people with deficiency syndrome. Although a larger sample size and longer treatment may be required for a more definite conclusion, this clinical trial is the first to disprove the common conception of "fireness" related to KRG.

• Journal of Global Scholars of Marketing Science
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• v.17 no.3
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• pp.83-108
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• 2007

Since the 1992 UN Conference for Environment and Development held in Rio de Jaineiro, Sustainable Development has become the global thesis. More than 170 countries signed the Agenda 21 for the sustainable action plan, and adopted the sustainability concept as the key concept of dealing with the environmental, social, ethical, and economic problem. Sustainability is one of the main marketing challenges in the 21st century. By integrating social and ecological criteria, marketing may can make valuable contributions to sustainable development. Regarding the sustainability marketing, it is difficult to find the domestic marketing research on the thesis of sustainable development, and this is the definite evidence that the Korean marketing researchers do not realize the importance of the thesis of sustainable development which is internationally suggested as the new paradigm of change. The purpose of this study is to build the conceptual background and explore the research direction in order to introduce and adopt the concept of sustainable development in the domestic marketing research field. The present paper proposes a comprehensive conception of sustainability marketing, defined by six step: analysis of social-ecological problems; analysis of consumer behavior; normative sustainability marketing; strategic sustainability marketing; instrumental sustainability marketing; and transformative sustainability marketing. The aim of the paper are to clarify the concept of sustainability marketing. To accomplish this research purpose we discuss the sustainable development which is the conceptual background of sustainability marketing, analyze the characteristics of the sustainability marketing, and finally summarize the research results and present the suggestions for further research. Sustainability marketing embraces the idea of sustainable development, a development that meets the needs of the present without compromising the ability of future generation to meet their own needs. Sustainability Marketing goes beyond conventional marketing thinking. If marketing is about satisfying customer needs and building profitable relationships with customers, sustainability marketing may be defined as building and maintaining sustainable relationships with customers, the social environment and natural environment. By creating social and environmental value, sustainability marketing tries to deliver and increase customer value. Sustainability Marketing aims at creating customer value, social value and environmental value. Sustainability marketing integrates social and ecological criteria into the whole process of marketing, and can be differentiated in six steps: (1) Analysis of the social and ecological problems, generally and specifically with respect to products which satisfy customer needs and wants; (2) Analysis of customer behavior with special aspect to social and ecological concerns; (3) Corporate commitments to sustainable development in the mission statement, development of sustainability visions, formulation of sustainable principles and guideline, setting of socio-ecological marketing objectives and goals (normative aspects of sustainability marketing); (4) Sustainability segmentation, targeting and positioning, and timing of market entry(strategic aspects of sustainability marketing); (5)Integration of social and ecological criteria into the marketing-mix, i.e. products, services and brands, pricing, distribution and communication(instrumental aspects of sustainability marketing); (6) Participation in public and political change processes, which transform existing institutions towards sustainability(transformative aspects of sustainability marketing). The first two steps begin with an analysis of the company situation. In sustainability marketing it is crucial not just to know consumer needs and wants, but also to find out about the ecological and social problems of products along their whole life cycle. The intersection of socio-ecological problems and consumer wants sets the ground for sustainability marketing. Step three to five describe the implementation of sustainability marketing. Social and ecological criteria are fully integrated into the mission statement, strategies and marketing-mix. Step six is one of the specifics of sustainability marketing. It is about the commitment of company to sustainable development and their active participation in public and political processes in order to change the existing framework in favor of sustainability.