• Title/Summary/Keyword: 과도 동역학

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The Philosophical Status of Scientific Theories for Science Education (과학교육을 위한 과학이론의 철학적 위치)

  • Jun-Young, Oh;Eun-Ju, Lee
    • Journal of the Korean Society of Earth Science Education
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    • v.15 no.3
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    • pp.354-372
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    • 2022
  • The purpose of this study is to explore the philosophical position of various scientific theories based on the scientific worldviews for science education. In addition, it aims to expand science education, which has usually dealt with epistemology and methodology, to ontology, that is, to the problem of metaphysics. It can be said that there exists a physical realism, traditionally defined as a strong determinism of the metaphysical belief. That is fixed and unchanging objective scientific knowledge independent of our minds, which was established by Newton, Einstein and Schridinger. What can be seen in the natural laws of dynamics can be called 'mathematicization'. Einstein also shook the traditional views to some extent through the theory of relativity, but his theory was still close to traditional thinking. On the contrary, to escape from this rigid determinism, we need anthropomorphic concepts such as 'possibility' and 'chance'. It is a characteristic of the modern scientific worldviews that leads the change of scientific theory from a classically strong deterministic thought to a weak deterministic accidental accident, probability theory, and a naturalistic point of view. This can be said to correspond to Darwin's theory of evolution and quantum mechanics. We can have three types of epistemological worlds that justify this ontological worldviews. These are rationalism, empiricism and naturalism. In many cases, science education does not tell us what kind of metaphysical beliefs the scientific theories we deal with in the field of education are based on. Also, science education focuses only on the understanding of scientific knowledge. However, it can be said that true knowledge can bring understanding only when it is connected to the knowledge of learned knowledge and the learner's own metaphysical belief in the world. Therefore, in the future, science education needs to connect various scientific theories based on scientific worldviews and philosophical position and present them to students.

STUDIES ON BRUCELLOSIS 2. Incidence of Brucellosis Reactors (BRUCELLOSIS에 관(關)한 연구(硏究) (제2보(第二報) 가축(家畜) BRUCELLOSIS에 대(對)한 역학적(疫學的) 조사보고(調査報告)))

  • Kim, Byong Koo;Song, Byoung Kyun;Lee, Taek Choo
    • Korean Journal of Veterinary Research
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    • v.1 no.1
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    • pp.53-53
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    • 1961
  • During the period from 1956 to 1959, a serological survey was conducted in au effort to assessing the incidence of brucellosis in various domestic animals in Korea. The following results were obtained. 1. Seventy-six dairy cattle which were imported in the year of 1956 had 9 positive reactors (11.84%). Of 1127 goats imported in 1956 and 1958, eleven(0.98%) were reactor animals. 2. In 1956, of 108 dairy cattle tested 10(9.25%) were reactors. In 1937 and 1958, a total of 155 dairy cattle examined hid ten (6.45%) positive reactors. In 1959, of 127 dairy cattle examined two were reactor animals. 3. In 1958 and 1959, 432 goats in some districts in Korea were subject to test for brucellosis and the test revealed five (1.15%) reactors. In 1958, 683 swine serum samples were examined and eleven (1.04%) were positive. In 1959, 1133 Korean cattle were tested and seven samples (0.64%) showed positive reactions. 4. In the month of July in 1939, 580 beef cattle in Cheju National Ranch and Branch were examined and 111 (19.13%) were found to be reactors. In October of the same year, 157 cattle, consisting of reactor and suspicious cattle groups, were tested, of which 71 samples reacted positive and 47 remained suspicious. 5. In December of the year of 1958, there occurred. an outbreak of brucellosis in a swine herd in the Sachon Branch Experimental Station. Seven serological tests on 438 swine serum samples were conducted, of which 122 (27.87%) were found positive. 6. Dairy cattle No. 33 and No. 35 which had been imported in 1956 and detected as highly positive, were examined for a prolonged period to follow the variation of antibody titers. A marked drop in antibody titer was seen two months after the initial test while the re-increase in titer was observer our months after the first examination.

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Analysis of Misconceptions on Oceanic Front and Fishing Ground in Secondary-School Science and Earth Science Textbooks (중등학교 과학 및 지구과학 교과서 조경 수역 및 어장에 관한 오개념 분석)

  • Park, Kyung-Ae;Lee, Jae Yon;Kang, Chang-Keun;Kim, Chang-Sin
    • Journal of the Korean earth science society
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    • v.41 no.5
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    • pp.504-519
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    • 2020
  • Oceanic fronts, which are areas where sea water with different properties meet in the ocean, play an important role in controlling weather and climate change through air-sea interactions and marine dynamics such as heat and momentum exchange and processes by which properties of sea water are mixed. Such oceanic fronts have long been described in secondary school textbooks with the term 'Jokyung water zone (JWC hereafter) or oceanic front', meaning areas where the different currents met, and were related to fishing grounds in the East Sea. However, higher education materials and marine scientists have not used this term for the past few decades; therefore, the appropriateness of the term needs to be analyzed to remove any misconceptions presented. This study analyzed 11 secondary school textbooks (5 middle school textbooks and 6 high school textbooks) based on the revised 2015 curriculum. A survey of 30 secondary school science teachers was also conducted to analyze their awareness of the problems. An analysis of the textbook contents related to the JWC and fishing grounds found several errors and misconceptions that did not correspond with scientific facts. Although the textbooks mainly uses the concept of the JWC to represent the meeting of cold and warm currents, it would be reasonable to replace it with the more comprehensive term 'oceanic front', which would indicate an area where different properties of sea water-such as its temperature, salinity, density, and velocity-interact. In the textbooks, seasonal changes in the fishing grounds are linked to seasonal changes in the North Korean Cold Current (NKCC), which moves southwards in winter and northwards in summer; this is the complete opposite of previous scientific knowledge, which describes it strengthening in summer. Fishing grounds are not limited to narrow coastal zones; they are widespread throughout the East Sea. The results of the survey of teachers demonstrated that this misconception has persisted for decades. This study emphasized the importance of using scientific knowledge to correct misconceptions related to the JWC, fishing grounds, and the NKCC and addressed the importance of transferring procedures to the curriculum. It is expected that the conclusions of this study will have an important role on textbook revision and teacher education in the future.

Dynamics of Barrel-Shaped Young Supernova Remnants (항아리 형태 젊은 초신성 잔해의 동력학)

  • Choe, Seung-Urn;Jung, Hyun-Chul
    • Journal of the Korean earth science society
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    • v.23 no.4
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    • pp.357-368
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    • 2002
  • In this study we have tried to explain the barrel-shaped morphology for young supernova remnants considering the dynamical effects of the ejecta. We consider the magnetic field amplification resulting from the Rayleigh-Taylor instability near the contact discontinuity. We can generate the synthetic radio image assuming the cosmic-ray pressure and calculate the azimuthal intensity ratio (A) to enable a quantitative comparison with observations. The postshock magnetic field are amplified by shearing, stretching, and compressing at the R-T finger boundary. The evolution of the instability strongly depends on the deceleration of the ejecta and the evolutionary stage of the remnant. the strength of the magnetic field increases in the initial phase and decreases after the reverse shock passes the constant density region of the ejecta. However, some memory of the earlier phases of amplification is retained in the interior even when the outer regions turn into a blast wave. The ratio of the averaged magnetic field strength at the equator to the one at the pole in the turbulent region can amount to 7.5 at the peak. The magnetic field amplification can make the large azimuthal intensity ratio (A=15). The magnitude of the amplification is sensitive to numerical resolution. This mens the magnetic field amplification can explain the barrel-shaped morphology of young supernova remnant without the dependence of the efficiency of the cosmic-ray acceleration on the magnetic field configuration. In order for this mechanism to be effective, the surrounding magnetic field must be well-ordered. The small number of barrel-shaped remnants may indicate that this condition rarely occurs.

Lew Seung Kug's Recognition on Relations between Juhng-yaug and History of Korean Thoughts (도원 류승국의 정역(正易)과 한국사상사의 상호 매개적 인식)

  • Yi, Suhngyohng
    • The Journal of Korean Philosophical History
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    • no.50
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    • pp.201-234
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    • 2016
  • This thesis examined interpreting methodology of Do Won Lew Seung Kug(1923~2011) is based on the principle of Juhng-yaug. His lifelong academic aim was searching for the theory that enables global community to co-exist peacefully through humanitarianism that leads to reconciliation and mutual benefits. The research of the history of Korean thoughts provided him with the clue for his theory. According to Do Won, Korean thoughts pursue the Juhng-yaug's value of 'Yin and Yang accordance' rather than the I-Ching's value of 'suppress Yin and elevate Yang'. He furthermore asserts the concept of the middle (中), which harmonizes the two extremes by human beings as main agents, has been consistently observed from the action of divination during the ancient period through Juhng-yaug in the late 19th century. Do Won identifies 'human maturity that integrates the extremely conflicting insistences and values and seeks to be reconciled' as the basic character of Korean thoughts. He explains 'Hongikingan[弘益人間, becoming beneficial to the human world] is the idea that embraces the conflicting values symbolized by heaven and the earth. He also illuminates that Choe Chi Won(崔致遠)'s created Poongliu Do by integrating heterogeneity among Confucianism, Buddhim, and Daoism and it was attainable through the various works of mature human beings. Both Toe Gye' s philosophy of Ingeuk(人極, the Great Ultimate of Person) and the concept of Innaecheon(人乃天, Human Being right is Heaven) of Donghak are excellent examples of Humanitarianism that sublate two extremes. In Korea, the prototype of this thought has penetrated its entire history in the various circumstances of the period. The grand finale is Juhng-yaug of which the pursued values are 'Yin and Yang accordance' and mature humanitarianism revealed by the thoughts of the Person of the Central Ultimate (皇極人,至人) and Central Ultimate (皇極). Therefore, Humanitarianism in Korean thoughts clearly makes its appearance by the time of Juhng-yaug and it functions as a keyword to illuminate the entire history of Korean thoughts in reverse.

Incidence and Risk Factors for Extended-Spectrum ${\beta}-Lactamase-Producing$ Escherichia coli in Community-acquired Childhood Urinary Tract Infection (지역사회 획득 소아 요로 감염에서 Extended-Spectrum ${\beta}-Lactamase$ 생성)

  • Lee Jung-Won;Shin Jee-Sun;Seo Jeong-Wan;Lee Mi-Ae;Lee Seung-Joo
    • Childhood Kidney Diseases
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    • v.8 no.2
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    • pp.214-222
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    • 2004
  • Purpose: Appropriate antibiotic therapy is important in childhood urinary tract infection and the selection of anibiotics is based on antimicrobial sensitivity of Escherichia coli. Extended-Spectrum ${\beta}-Lactamase(ESBL)$ is an enzyme produced by gram-negative bacilli that has the ability to hydrolyse penicillins, broad-spectrum cephalosporin and monobactam. There have been many reports of outbreaks of hospital infection by ESBL-producing organism. However, community-acquired infection with ESBL-producing organism are rare. This study was performed to retrospectively identify the incidence, characteristics and risk factors of ESBL (+) E. coli in community-acquired childhood UTI. Methods: In 288 children admitted in Ewha Womans University Hospital with E. coli UTI from Mar 2001 to February 2003, ESBL was isolated. ESBL was confirmed by the utilization of an automatized machine(Vitek GNS 433 card) using liquid medium dilution method according to National Committee for Clinical Laboratory Standard. The clinical characteristics, risk factors, antimicrobial resistance and treatment effectiveness were compared with ESBL(-) E. coli UTI. Results: Of 288 E. coli isolates, 31(10.8%) produced ESBL and 93.5%(29/31) occurred in infants younger than 6 month of age(P<0.01). No significant differences were noted in prior antibiotic use, prior admission history and underlying urogenital anomaly. Antimicrobial resistance was significantly higher in ESBL(+) E. coli compared with control patients (P<0.05). Although ceftriaxone showed 100% resistance in ESBL(+) E. coli, bacteriologic sterilization rate after ceftriaxone therapy was higher(96.8%). However, the recurrence rate of febrile UTI within 6 months was higher(25.8%) than control patients(6.6%). Conclusion: Epidemiologic study is required to find out any new risk factors of community-acquired ESBL(+) E. coli UTI and changes in selection of empirical antibiotics should be considered.

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Physico-Chemical Factors on the Growth of Cochlodinium polykrikoides and Nutrient Utilization (Cochlodinium polykrikoides의 성장에 미치는 물리$\cdot$화학적 요인과 영양염 이용)

  • KIM Hyung Chul;LEE Chang Ku;LEE Sam Geun;KIM Hak Gyoon;PARK Chung Kil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.34 no.5
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    • pp.445-456
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    • 2001
  • In the 1990s, Cochlodinium polykikoides red tide has been annually occurred in the southern coast of Korea and caused the mass damage to the fisheries with a huge amount of economic loss. The present study was done to establish the biological foundation for the elucidation of the mechanism of C. polykikoiaes red tide. The growth response of C. polykikoides to physico-chemical factors such as temperature, salinity, pH, and light intensity were examined using axenic cultures to evaluate the relative importance of these factors on the dynamics of natural populations, It was found that the highest growth conditions were $25^{\circ}C,\;40\%_{\circ}$, pH 7.5, and 7,500 lux, respectively. The tolerable salinity range of growth was relatively wide at an optimum temperature and was reduced to a much narrower range at a sub-optimum temperature. These findings indicate that C. polykikoides is an eurythermal and euryhaline organism. The organism demanded higher light intensity and oceanic pH narrow in its growth. C. polykikoides utilize inorganic nutrients, such as nitrate and ammonium as N, and phosphate as P. The nutritional requirements of C. polykikoides were $40{\mu}M$ for nitrate, $50{\mu}M$ for ammonium, and $5{\mu}M$ for phosphate. The half saturation constant (Ks) for growth was $2.10{\mu}M$ for nitrate, $1.03{\mu}M$ for ammonium, and $0.57{\mu}M$ for phosphate. These values were comparatively smaller than those of other dinoflagellates reported previously. We confirmed that the organism is characterized as an eutrophic species. However, ammonium Ks value is smaller than that of other eutrophic species, This result indicates that C. polykikoides red tide may outbreak in the waters which eutrophication is in progress rather than eutrophicated waters. C. polykikoides preferred ammonium better than nitrate as a nitrogen source when in a growth stage, Therefore, our results indicate that ammonium is more important nutrient on the growth of the organism in comparison with other inorganic nutrients and C. polykikoides red tide is related with the increased ammonium concentration in the coastal waters.

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A Numerical Study on the Characteristics of Flows and Fine Particulate Matter (PM2.5) Distributions in an Urban Area Using a Multi-scale Model: Part II - Effects of Road Emission (다중규모 모델을 이용한 도시 지역 흐름과 초미세먼지(PM2.5) 분포 특성 연구: Part II - 도로 배출 영향)

  • Park, Soo-Jin;Choi, Wonsik;Kim, Jae-Jin
    • Korean Journal of Remote Sensing
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    • v.36 no.6_3
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    • pp.1653-1667
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    • 2020
  • In this study, we coupled a computation fluid dynamics (CFD) model to the local data assimilation and prediction system (LDAPS), a current operational numerical weather prediction model of the Korea Meteorological Administration. We investigated the characteristics of fine particulate matter (PM2.5) distributions in a building-congested district. To analyze the effects of road emission on the PM2.5 concentrations, we calculated road emissions based on the monthly, daily, and hourly emission factors and the total amount of PM2.5 emissions established from the Clean Air Policy Support System (CAPSS) of the Ministry of Environment. We validated the simulated PM2.5 concentrations against those measured at the PKNU-AQ Sensor stations. In the cases of no road emission, the LDAPS-CFD model underestimated the PM2.5 concentrations measured at the PKNU-AQ Sensor stations. The LDAPS-CFD model improved the PM2.5 concentration predictions by considering road emission. At 07 and 19 LST on 22 June 2020, the southerly wind was dominant at the target area. The PM2.5 distribution at 07 LST were similar to that at 19 LST. The simulated PM2.5 concentrations were significantly affected by the road emissions at the roadside but not significantly at the building roof. In the road-emission case, the PM2.5 concentration was high at the north (wind speeds were weak) and west roads (a long street canyon). The PM2.5 concentration was low in the east road where the building density was relatively low.