• Title/Summary/Keyword: "물리학"(物理學)

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Manufacture of Flow Phantom with Stenosis and Imaging Evaluation of Power Doppler (혈관협착팬텀의 제작 및 파워도플러의 영상 평가)

  • Park, Hee-Young;Bae, Jong-Rim;Kim, Jeong-Koo
    • The Journal of the Acoustical Society of Korea
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    • v.28 no.8
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    • pp.732-739
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    • 2009
  • Flow phantom with stenosis was manufactured using an auto-injector to obtain angiostenotic flow information and quality assurance (QA) for ultrasound diagnostic instrumentation. Effectiveness of manufactured flow phantom with stenosis was investigated with power Doppler that was known to have diagnostic efficiency for angiostenosis. The flow phantom with stenosis was manufactured to 70% stenosis with 8 mm and 2.4 mm silicon tube, and silicone tube was covered with gelatin that has acoustic characteristics similar to soft tissue. When the linear transducer was used for measurement, the estimated diameter of normal vessel was measured lower than that of normal value, and the estimated diameter of stenosed vessel was measured higher than that of normal value. The measured parameters were not affected except for the radical conditions such as gain of 60%, PRF of 3000 Hz, use of maximal filter or angle. In addition, when the convex transducer was used for measurement, measurement parameters were affected by gain, PRF, filter, and angle. Therefore it is expected that flow phantom with stenosis manufactured with an auto-injector will be utilized effectively for QA of angiostenotic diagnosis.

Proposal Strategy and Establishment Process of a New Scientific Theory Examined through the Theory of Continental Drift (대륙이동설을 통해 살펴본 새로운 과학이론의 제안전략과 확립과정)

  • Jun-Young Oh;Eun-Ju Lee
    • Journal of the Korean Society of Earth Science Education
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    • v.17 no.1
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    • pp.20-33
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    • 2024
  • The purpose of this study is to examine the scientific activities of scientists justifying Wegener's continental drift in the 20th century, which is explained as a revolutionary process in earth science, and methodologically analyze the strategy of proposing new scientific theories and how the process of theory selection is carried out. Previously, the Earth was a static model and only the vertical movement of the crust was considered. However, the theory of continental drift proposed horizontal movement of the crust as a dynamic model of the Earth, eliminating numerous problems. Therefore, this study seeks to explore the rational activities of numerous scientists until the current plate tectonics theory was formed. Additionally, the theory of continental drift is in conflict with the theory of Earth shrinkage, which is an existing static model. In other words, it deviates from the existing mechanistic world view by presenting a dynamic model in which the Earth is created and changes, as opposed to a static model in which the Earth is already completed, fixed, and unchanged. As a result, old geology was weakened and new geophysics was born. The theory of continental drift and continued exploration by subsequent generations of scholars brought about a revolution in earth science. This can be said to be a good subject of investigation as educational material for various methodologies for students in earth science education, and as educational material for changing students' worldview.

Study on Comarison of Homeopathy with Sa-sang constitutional Medicine in Basic Principles from the literature (동종요법의 기본원리와 사상체질의학의 비교연구)

  • An, Sang-Woo;Cho, Hwang-Sung
    • Journal of Sasang Constitutional Medicine
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    • v.8 no.2
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    • pp.165-190
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    • 1996
  • Homoeopathy was established in 1796 by German physician Samuel Hahnemann(1755~1843). This method is an alternative form of therapy involving treatment by natural remedies. The basic principles of homeopathic medicine, "Similia similibus curantur", "experimenta in hominesano", "doses minimae" and "unitas remedii", are founded upon the idea of illness as a disorder of the internal equilibrium at the physical, mental and psychic levels. The three distinguishing characteristics of homeopathy are that remedies are prescribed on the totality of a person's symptoms, that the remedy likely to cure a person is a dilution of that remedies are prepared using microdoses of substances which are diluted and then vigorously shaken. This paper describes the basic principled of homeopathy and compared with the Sa-sang constitutional Medicine from the literature. 1. Homeopathy is the holistic medicine that derived from the competition of vitalism and mechanism, and it is the one of natural medicine that absorbed the influence of asian scholarship and theoretical background of oriental medicine. 2. Homeopathic remedy typologies and Sa-sang constitutional Medicine are same in the mind-body correlativity and in-born typologies. 3. In homeopathy, constitutional types are distinguished the variable types with variety of symptoms by the remedy picture, but comparably in Sa-sang constitutional medicine, it is determined only by the constitutional symptoms.

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The status and future of the geomatics - about satellite geodesy and remote sensing (공간정보기술의 현황 및 전망 - 위성측지 및 원격탐사를 중심으로)

  • 안철호
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2002.04a
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    • pp.3-10
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    • 2002
  • 요즘 측량분야에서 Geomatics 또는 Geoinformatics라는 새로운 용어가 대두되고 있다. 해외의 유수 기관 및 대학교에서도 측량이라는 학과명 또는 기관명을 Geomatics라는 용어로 교체하고 있으며, 이는 측량분야의 다양화와 학제간 연구수행의 필요성을 반영하는 것이다. 최근 45로 일컬어지는 GPS, 원격탐사(RS), GIS, ITS의 경우 각기 독자적인 영역을 구축하기보다는 상호 보완적인 역할을 하며 통합되어 가는 추세이다. 1950년대에 기본적인 위성관측기술 및 계산 기술의 개발을 시작으로 1980년대에 이르러서는 위성 기술은 측지학 및 측량 분야에 적용되기 시작했다. 그 대표적인 것이 GPS(Global Positioning System)로 기존의 천체측정학 방식을 대체하는 유용한 위치결정 수단으로 사용되기 시작했다. DNSS로부터 시작된 GPS는 측지 측량분야, 지구물리학분야, 항법 및 교통, GIS Mapping, 기상 및 해양, 재난 및 레저, 인공위성 궤도결정 등 다양한 분야에 적용되었으며, 특히 2000년 5월 1일 SA가 해제되면서 그 활용도는 더욱 증가하고 있다. 위성원격탐사의 경우 초창기에 중ㆍ저해상도의 다중분광영상에서 시작하여 그 해상도가 꾸준히 향상되어 오늘날 0.61 미터급 고해상도 위성인 QuickBird 위성이 발사되어 운용 중에 있다. 위성영상의 공간해상도, 분광해상도, 방사해상도는 향후 계속 향상될 것이며 이에 따른 방대한 데이터의 처리 문제 및 하드웨어/소프트웨어 지원에 대한 연구가 수반되어야 할 것이다. GPS 및 원격탐사(RS)는 더 이상 독자적인 영역으로서가 아니라 Geomatics를 이루는 중요한 분야로서 타 시스템과의 보완적인 관계로서 통합되어 나갈 것이다. 이를 위해서는 공간정보에 대한 표준화 및 데이터 처리, 통합, 시스템 구축을 위한 기술적 연구가 계속 진행되어야 할 것이다.분 공부상면적보다 늘어났다. 2. 좌표의 이동량이 일률적이지 못하므로 기초점에 대한 문제라고 생각되며, 따라서 도해지적을 수치지적으로 전환함에 있어서 가장 우선되어야 할 사항이 기초점 정비라 하겠다.승이 뚜렷하였다. 따라서 비파 착즙액 첨가 기능성 yoghurt 제조시 비파 착즙액을 10% 첨가하여 혼합 starter로 Str. thermophilus와 Lac. acidophilus 혼합균주를 사용하는 것이 이들 유산균의 증식에 가장 적합한 것으로 나타났다.타났다..297, 0.293, 0.205에서 50일 경과 후 0.612, 0.472, 0.898로 비살균에서 높은 값을 보였다. 따라서 비살균의 경우 저장말기에 TBA값이 높아지는 경향을 보였다. 5. L값은 살균처리의 경우 저장 30일 이후 약간 어두워지는 경향을 보였고, 121$^{\circ}C$ 살균처리에서 높은 값을 보였다. 대체로 저장온도가 높고 저장기간이 길어질수록 약간 밝아지는 경향을 보였다. 적색도는 인삼 첨가구의 경우 상온 및 냉장저장에서 10$0^{\circ}C$ 살균이 121$^{\circ}C$ 처리구 보다 약간 높은 값을 보였다. 저장기간에 따른 적색도의 변화는 인삼과 송이 첨가구에서 비교적 안정적이었다. 황색도는 상온 및 냉장저장에서 저장기간에 따라 약간 감소하는 경향을 보인 후 상온저장 50일 째, 냉장 60일 째 가장 높게 나타났다. 121$^{\circ}C$ 살균처리구가 10$0^{\circ}C$ 처리구보다 약간 높은 경향을 보였다.^{\circ}C$$,에서는 20시간 가열시 0.706$\mu\textrm{g}$/kg으로 가장 높게 생성된 후 서서히 감소하였다. 그러나 산값과 공액이중산값은 계속 증가하는 양상을 나타냈다. 즉 B(a)

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A study of the Implications of French vocabularies and the de-locality in LEE Sang's Poems (이상(李箱)의 시 작품에 구사되는 프랑스어와 탈 지방성)

  • Lee, Byung-soo
    • Cross-Cultural Studies
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    • v.53
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    • pp.1-24
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    • 2018
  • This following research is a study on the use of French and de-locality in the modern Korean poet Lee Sang's poetry (1910-1937). His hometown was Kyung Sung, Seoul. He mainly wrote his works in Korean, Chinese character, and Japanese, using the language of education and his native language at that time. So then, what was the spirit that he wanted to embody through use of French words? By using words like "ESQUISSE", "AMOUREUSE", Sang's French was not a one-time use of foreign words intended to amuse, but to him the words were as meticulously woven as his intentions. French words were harmonized with other non-poetic symbols such as "${\Box}$, ${\triangle}$, ${\nabla}$", and described as a type of typographical hieroglyphics. Instead of his mother-tongue language, French was applied as a surrealistic vocabulary that implemented the moral of infinite freedom and imagination, and expressed something new or extrasensory. Subsequently, the de-localized French (words) in his poetry can be seen as poetic words to implement a "new spirit", proposed by western avant-garde artists. Analysis of French in his poetry, showed a sense of yearning for the scientific civilization, calling for his sense of defeat and escape from the colonized inferior native land. Most of all, comparing his pursuit of western civilization and avant-garde art to French used in his poetry, is regarded as world-oriented poetry intended to implement the new tendency of the "the locomotive of modernity," transcending the territory of the native country.

Hexagonal shape Si crystal grown by mixed-source HVPE method (혼합소스 HVPE 방법에 의해 성장된 육각형 Si 결정)

  • Lee, Gang Seok;Kim, Kyoung Hwa;Park, Jung Hyun;Kim, So Yoon;Lee, Ha Young;Ahn, Hyung Soo;Lee, Jae Hak;Chun, Young Tea;Yang, Min;Yi, Sam Nyung;Jeon, Injun;Cho, Chae Ryong;Kim, Suck-Whan
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.31 no.3
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    • pp.103-111
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    • 2021
  • Hexagonal shape Si crystals were grown by the mixed-source hydride vapor phase epitaxy (HVPE) method of mixing solid materials such as Si, Al and Ga. In the newly designed atmospheric pressure mixed-source HVPE method, nuclei are formed by the interaction between GaCln, AlCln and SiCln gases at a high temperature of 1200℃. In addition, it is designed to generate a precursor gas with a high partial pressure due to the rapid reaction of Si and HCl gas. The properties of hexagonal Si crystals were investigated through scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), high-resolution X-ray diffraction (HR-XRD), and Raman spectrum. From these results, it is expected to be applied as a new material in the Si industry.

Growth of hexagonal Si epilayer on 4H-SiC substrate by mixed-source HVPE method (혼합 소스 HVPE 방법에 의한 4H-SiC 기판 위의 육각형 Si 에피층 성장)

  • Kyoung Hwa Kim;Seonwoo Park;Suhyun Mun;Hyung Soo Ahn;Jae Hak Lee;Min Yang;Young Tea Chun;Sam Nyung Yi;Won Jae Lee;Sang-Mo Koo;Suck-Whan Kim
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.33 no.2
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    • pp.45-53
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    • 2023
  • The growth of Si on 4H-SiC substrate has a wide range of applications as a very useful material in power semiconductors, bipolar junction transistors and optoelectronics. However, it is considerably difficult to grow very fine crystalline Si on 4H-SiC owing to the lattice mismatch of approximately 20 % between Si and 4H-SiC. In this paper, we report the growth of a Si epilayer by an Al-related nanostructure cluster grown on a 4H-SiC substrate using a mixed-source hydride vapor phase epitaxy (HVPE) method. In order to grow hexagonal Si on the 4H-SIC substrate, we observed the process in which an Al-related nanostructure cluster was first formed and an epitaxial layer was formed by absorbing Si atoms. From the FE-SEM and Raman spectrum results of the Al-related nanostructure cluster and the hexagonal Si epitaxial layer, it was considered that the hexagonal Si epitaxial layer had different characteristics from the general cubic Si structure.

A Comprehensive Study on the Forced Aging of Flue-cured Tobacco-Leaves (황색종 잎담배의 발효숙성 촉진에 관한 종합적 연구)

  • Bae, H.W.
    • Applied Biological Chemistry
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    • v.13 no.1
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    • pp.1-27
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    • 1970
  • The process of the forced aging of flue-cured tobacco leaves were studied extensively from various scientific points of view. The Flue-cured tobacco leaves were inoculated and fermented with nicotine resistant Hansenula yeast, or the leaves were subjected under simple forced aging. The above two processes of forced aging were studied from the summarized points of microbiology, physics, chemistry, and biochemistry, and the resulted products ware compared in their physical, chemical and biochemical quality determining factors with that of raw material tobacco leaves (dried-tobacco leaves) and 2 years aged high quality tobacco leaves. The summary results were as follows. 1) The Korean flue-cured tobacco leaves, were forcedly aged under the basic optimum aging condition, temperature $40^{\circ}C$, moisture contents 18%, relative humidity 74%. It was found that this aging condition was the best in bringing the quality of forcedly aged tobacco leaves to the utmost state. 2) Under this optimum temperature and moisture condition of forced aging in about 20 days the forcedly aged tobacco leaves both with yeast inoculation and without yeast inoculation showed the equivalent tobacco qualities comparable with that of more than 2 years aged tobacco leaves. 3) The forcedly aged tobacco leaves both with and without yeast inoculation under $40^{\circ}C$ temperature and $74^{\circ}C$ relative humidity achieved the necessary quality determining physical and chemical changes in about 20 days. 4) The microbial changes during the forced aging were as follows. The population of yeasts and bacteria increased until to 15 days of aging, then decreased thereafter. Whereas the molds grew continously until the end of fermentation. 5) The tobacco quality determing physico-chemico-properties of yeast inoculated aged and simple forcedly aged tobacco leaves, progressed as the follows in time. As the forced aging progresses, swelling and combustibility properties were improved. The pH, total reducing materials, total sugars, alkaloids contents decreased. The contents of organic and ether extractable materials increased. The total nitrogen, protein, crude fiber, ash contents showed no changes. The color properties, excitation purity, luminance, main wave length, showed equivalent changes comparable with that of 2 years aged tobacco leaves. 6) The changes in chemical components in yeast treated and simple forcedly aged tobacco leaves during $15{\sim}20{\;}days$ of forced aging were as follows. The following chemical components decreased as the aging. Sugars-sucrose. rhamnose, glucose. Pigments-chlorophyll, carotenes, xanthophyll and violax anthine. Polyphenols-rutin, chlorogenic and, coffeic acid. Organic acids-iso-butylic, crotonic, caprylic, galacturonic, tartaric, succinic, citric acid. Alkaloids-nicotine, nornicotine. The following components increased as the forced aging progressed. Sugars-frutose, maltose, raffinose. Amino acids-proline, cystine. Organic acids-formic, acetic, propionic, n-butyric, iso-valeric, n-valeric, malic, oxalic, malonic, ${\alpha}-ketoglutaric$, fumaric, glutaric acid. 7) During the forced aging of tobacco Leaves the oxygen-uptake decreased gradually. The enzyme activities of polyphenol oxidase, ${\beta}-amylase$ ${\alpha}-amylase$ decreased gradually. The activities of the enzymes, catalase, and invertase increased once then decreased at the later stage.

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An Exploration on Public Perception of Social Welfare as a Discipline in Korea (사회복지학에 대한 한국인의 인식에 관한 연구)

  • Kang, Chul-Hee
    • Korean Journal of Social Welfare
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    • v.57 no.4
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    • pp.147-175
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    • 2005
  • Efforts to identify the public's perception of social welfare as an academic discipline have never been conducted in Korea since the establishment of social welfare department in 1947 at Ewha Womans University. Such efforts are very meaningful in identifying directions and tasks to strengthen Korean social welfare as well as in clarifying and promoting our understanding concerning status of the academic discipline. This study attempts to explore and describe the degree of the public's perception in Korea with analyzing data surveyed in 2004 by our interdisciplinary research team. This study develops and uses a questionnaire having a Likert scale format that is composed of 8 points and measures the public's perception in the following dimensions: (1) personal interests on academic discipline; (2) contribution of academic discipline; (3) prospect of academic discipline; (4) importance of academic discipline; (5) expertise of academic discipline; and (6) personal knowledge on academic discipline. To avoid social desirability and promote objectivity with comparative measurement, this study selects ten representative academic disciplines as follows: medicine; physics; biology; social welfare; economics; psychology; sociology; political science; library science; and communication & journalism. This study attempts to identify (1) the degree of the public's perception on ten academic disciplines; (2) the position of social welfare by comparing it with each academic discipline and by comparing mean of social welfare with overall mean of six social science disciplines in the six dimensions; (3) the differences in the public's perceptions of social welfare on six dimensions by the respondents' status factor(high school students, college and graduate students, and citizens) and gender factor by using MANCOVA, and (4) the differences in the public's perceptions of social welfare on six dimensions by major factor(social welfare, social science majors, and natural science majors) and gender factor of college and graduate school students by using MANCOVA. The results of data analysis are as follows: (1) while the 3,319 respondents gave relatively high rating on natural sciences in the dimensions of contribution and expertise, they did the same on social sciences in the dimensions of personal interests and personal knowledge; (2) in overall comparisons, while the 3,319 respondents gave relatively high rating on social welfare in the dimensions of contribution, prospect and importance, they gave the lowest rating on the expertise of social welfare; (3) in the comparisons with social science disciplines, while the 3,319 respondents gave relatively high rating on social welfare in the dimensions of contribution, prospect and importance, they gave the lowest rating on the expertise of social welfare; (4) when analyzing all the respondents, there were differences in the vector of personal interests, contribution, prospect, importance, expertise, and personal knowledge by status factor, gender factor, and interaction effect factor; and (5) when analyzing only the respondents in college and graduate schools, there were differences in the vector of personal interests, contribution, prospect, importance, expertise, and personal knowledge by only major factor and gender factor. The results provide empirical backgrounds for discussing current image, status and major characteristics of social welfare as a discipline in Korea. Indeed, this study provides new meaningful and thoughtful guide for further investigation on the topic. In addition, contributing to clarifying and broadening our understandings about the public's perception on social welfare in Korea, this study discusses the tasks for dealing with expertise issue that is the most vulnerable issue of Korean social welfare discipline and research directions to strengthen and promote social welfare discipline in Korea.

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A Study on Stochastic Wave Propagation Model to Generate Various Uninterrupted Traffic Flows (다양한 연속 교통류 구현을 위한 확률파장전파모형의 개발)

  • Chang, Hyun-Ho;Baek, Seung-Kirl;Park, Jae-Beom
    • Journal of Korean Society of Transportation
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    • v.22 no.4 s.75
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    • pp.147-158
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    • 2004
  • A class of SWP(Stochastic Wane Propagation) models microscopically mimics individual vehicles' stochastic behavior and traffic jam propagation with simplified car-following models based on CA(Cellular Automata) theory and macroscopically captures dynamic traffic flow relationships based on statistical physics. SWP model, a program-oriented model using both discrete time-space and integer data structure, can simulate a huge road network with high-speed computing time. However, the model has shortcomings to both the capturing of low speed within a jam microscopically and that of the density and back propagation speed of traffic congestion macroscopically because of the generation of spontaneous jam through unrealistic collision avoidance. In this paper, two additional rules are integrated into the NaSch model. The one is SMR(Stopping Maneuver Rule) to mimic vehicles' stopping process more realistically in the tail of traffic jams. the other is LAR(Low Acceleration Rule) for the explanation of low speed characteristics within traffic jams. Therefore, the CA car-following model with the two rules prevents the lockup condition within a heavily traffic density capturing both the stopping maneuver behavior in the tail of traffic jam and the low acceleration behavior within jam microscopically, and generates more various macroscopic traffic flow mechanism than NaSch model's with the explanation of propagation speed and density of traffic jam.