• Title/Summary/Keyword: earth's core

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Evaluating Shear Wave Velocity of Rock Specimen Through Compressional Wave Velocities Obtained from FFRC and Ultrasonic Velocity Methods (양단자유공진주 및 초음파속도법으로 획득한 압축파 속도를 이용한 암석시편의 전단파 속도 도출)

  • Bang, Eun Seok;Park, Sam Gyu;Kim, Dong Soo
    • Geophysics and Geophysical Exploration
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    • v.16 no.4
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    • pp.250-256
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    • 2013
  • Using shear wave velocity is more reasonable to estimate strength and integrity of rock compared with using compressional wave. It is often ambiguous to pick the dominant frequency caused by torsional wave when evaluating $V_S$ of rock specimen from FFRC method. It is also sometimes ambiguous to pick the first arrival point of S wave compared with P wave in the signals acquired from ultrasonic velocity method. Otherwise, the procedure of evaluating $V_P$ using ultrasonic velocity method and $V_L$ using FFRC method is relatively stable. Through the relationship between elastic modulus, poisson's ratio and $V_S$ can be obtained from $V_P$, $V_L$. Applicability was checked using model specimens having different material property and length and rock specimens sampled in mine area, and usefulness of proposed procedure was verified.

Teacher Perception of Science Competency and Science PCK for Competency-Based Science Education in the Future Society (미래사회 과학 역량에 대한 교사 인식과 역량기반 과학교육을 위한 교사 전문성 탐색)

  • Kwak, Youngsun;Hong, Seok-Young
    • Journal of The Korean Association For Science Education
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    • v.42 no.2
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    • pp.265-275
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    • 2022
  • In this study, focusing on science education in the future society, we explored students' key competencies to be cultivated for the future society, and the role and PCK expertise necessary for science teachers, who are the main agents of competency-based education to nurture these key competencies. A survey conducted among earth science teachers across the country results in 105 valid responses being obtained. The research results are discussed in terms of students' key competencies to be nurtured for the future society, the role and the expertise of science teachers required for competency-based education, and the structural relationship between the teacher role and teacher expertise. We also conducted network analysis to examine the relationship between student competency and teacher expertise, and the structure between the teacher's role and expertise. Main results include that communication and collaboration skills are the most important for students in the future society as core competencies. For science teachers, providing opportunities for collaboration-oriented activities are deemed as the most important. Regarding the structural relationship between the teacher's role and the teacher's expertise, there is a clear relationship with roles such as providing opportunities for collaboration-oriented activities and utilizing various materials and contents in relation to the expertise related to the science teaching practice. Based on the results, ways to promote student's agency based on raising teachers' awareness of the student's competencies, the inter-relatedness of the teacher's role and the teacher's expertise, and the totality of teachers' expertise were suggested.

Simultaneous tomographic inversion of surface and borehole seismic traveltime data in the Pungam basin (풍암분지 시험시추공 주변에서의 지표 및 시추공 초동주시 토모그래피 동시역산)

  • Hong, Myung-Ho;Kim, Ki-Young
    • 한국지구물리탐사학회:학술대회논문집
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    • 2006.06a
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    • pp.125-130
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    • 2006
  • Both surface seismic and far-offset VSP data were recorded alongtwo mutually perpendicular profiles in the Pungam basin. The first-arrival times were simultaneously inverted using the tomography method. For the surface data, seismic energy was generated by a 5-kg sledgehammer at 48 stations and detected by 21 surface geophones at 3 m intervals and one 3-component geophone in test borehole for the purpose of static corrections. For the VSP data, seismic waves generated by the sledgehammer on the ground were detected by a 3-component borehole geophone in a depth range of $9{\sim}99\;m$. Delay times of the hammer data were corrected using the seisgun data before the inversion to yield velocity tomograms. The tomograms indicates that the soil layer with velocities less than 750 m/s averages 1.8 m thick. The velocity varies from 5353 m/s at the depth range of $31{\sim}40\;m$ to 4262 m/s at the depth range of $65{\sim}73\;m$. Compared with core samples, the relatively large variation in velocity may due to lithology changes and fracture effects with depth.

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Petrology of the Blastoporphyritic Granite Gneiss in the Southwestern Part of the Sobaegsan Massif (소백산육괴 서남부의 잔류반상 화강편마암의 암석학적 연구)

  • Lee, Choon-Hee;Lee, Sang-Won;Ock, Soo-Seck;Song, Young-Sun
    • Journal of the Korean earth science society
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    • v.22 no.6
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    • pp.528-547
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    • 2001
  • The blastoporphyritic granite gneiss (BPGN) including much alkali-feldspar megacrysts occurs in Jiri mountains area, southwestern part of Sobaegsan massif, Korea. The BPGN is formed gneiss complexes with other gneisses in Precambrian. The BPGN was named as porphyroblastic gneiss with porphyroblasts of alkali-feldspar megacrysts by other researchers, but the BPGN includes of euhedral alkali-feldspars (microcline), and the boundary with the granitic gneiss represents sharp contact as intrusive relationship. The BPGN mainly composes of alkali-feldspar megacrysts, quartz, plagioclase, K-feldspar and biotite some almandine and accessary minerals are muscovite, chlorite, apatite, zircon and opaques. The alkali-feldspar is microcline with perthitic texture. An content of plagioclases show 30 to 40. Biotites occur two type, one is Brown biotite which shows compositional ranges of Mg/Fe+Mg ratios from 0.38 to 0.52, the other is Green Bt. which is retrograde product. Camels to be various sizes and shapes have composition of almandine with 73 to 80 mole percent, but represent retrogressive zoning from core (X$_{pyr}$: 15.9${\sim}$20.8) to rim (X$_{pyr}$:13.7${\sim}$15.9) to be evidence of retrograde metamorphism. Megacrysts of alkali-feldspar in the BPGN show rectangular shape of euhedral and some become ellipsoidal or spheroidal in shape and the average size up to 20 cm long. The megacryst includes of biotite, plagioclase and quartz, and rarely euhedral apatite as inclusions. In petrochemistry the BPGN represents granodiorite composition, characteristics of peraluminous S-type granitoid and calc-alkaline features.

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An attempt at soil profiling on a river embankment using geophysical data (물리탐사 자료를 이용한 강둑 토양 종단면도 작성)

  • Takahashi, Toru;Yamamoto, Tsuyoshi
    • Geophysics and Geophysical Exploration
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    • v.13 no.1
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    • pp.102-108
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    • 2010
  • The internal structure of a river embankment must be delineated as part of investigations to evaluate its safety. Geophysical methods can be most effective means for that purpose, if they are used together with geotechnical methods such as the cone penetration test (CPT) and drilling. Since the dyke body and subsoil in general consist of material with a wide range of grain size, the properties and stratification of the soil must be accurately estimated to predict the mechanical stability and water infiltration in the river embankment. The strength and water content of the levee soil are also parameters required for such prediction. These parameters are usually estimated from CPT data, drilled core samples and laboratory tests. In this study we attempt to utilise geophysical data to estimate these parameters more effectively for very long river embankments. S-wave velocity and resistivity of the levee soils obtained with geophysical surveys are used to classify the soils. The classification is based on a physical soil model, called the unconsolidated sand model. Using this model, a soil profile along the river embankment is constructed from S-wave velocity and resistivity profiles. The soil profile thus obtained has been verified by geotechnical logs, which proves its usefulness for investigation of a river embankment.

Understanding of I-Ching at a Viewpoint of Analytic Psychology - In a Basis at Ch'ien(乾) and K'on(坤) - (『주역(周易)』의 분석심리학적 이해 - 건괘(乾卦)·곤괘(坤卦)를 중심으로 -)

  • Shin, Sung-soo;Lee, Hyeon-gu
    • Cross-Cultural Studies
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    • v.31
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    • pp.119-153
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    • 2013
  • There is the commonness between I-Ching of Asian scriptures and Analytic Psychology of C. G. Jung as the conjunction of opposites of yin and yang. I-Ching has the base of the Great Absolute(太極) as yin and yang. Jung's psychology has the basic structure of opposite contents of psyche. The former wants to find the proper answer for the situation as fortune book, the latter realization of personal psyche. At this basis to approach I-Ching through the Analytic Psychology can be connected with the screening its inner system and structure in the frame of depth psychology. Basically I-Ching is the scripture about the good or ill luck, regret and stinginess. All of them are related with the psychology of human beings practically. I-Ching as the main scripture of Asia has the core theme concept of the mean (中). Previously mentioned the good or ill luck, regret and stinginess are included into this as the large view point. The best decision between the given situation and the fortune teller pursues the mean(中) path of both. Jung's psychology also attaches importance to the proper balance among personal conscious, unconscious and his surrounded situations. Goodness is relied on the mean, healthy psyche the harmony with the psychological and real situations of a person. But this balance and mean cannot be achieved without any reason but by the result of the conjunction of opposites. The opposites are the Ch'ien(乾, the Creative, Heaven) and K'un(坤, the Receptive, Earth) as yin and yang in I-Ching and the conscious and unconscious in Jung's psychology. These can be opened to masculine and feminine, psyche and matter, transcendent and existence and casuality and acausal synchronicity. Conjunction of these opposites can develope and create the new conscious and creative situation. Finally yin and yang from the Great Absolute and conscious and unconscious from Self become the opposites and go through necessary step of separation and sublimation for the creation of new level. In the Great Absolute there are yin and yang and yin the latter contains the cyclic process which can make the former renew. Conjunction of opposite in Jung's psychology also go through the similar process as the Great Absolute of yin and yang.

Sources Identification of Anthropogenic Pb in Ulleung Basin Sediments using Stable Pb Isotope Ratios, East/Japan Sea (동해 울릉분지 시추 퇴적물에서 안정 Pb 동위원소를 이용한 Pb의 기원 추정)

  • Choi, Man-Sik;Uoo, Jun-Sik;Kim, Dong-Seon
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.12 no.4
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    • pp.315-327
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    • 2007
  • This study investigated temporal and spatial variation of Pb and stable Pb isotopes accumulated in Ulleung Basin core sediments (4) using MC ICP/MS in order to identify the sources of anthropogenic Pb in the East/Japan Sea. Leached (1M HCl) Pb concentration and isotope ratios ($^{207}Pb/^{206}Pb\;and\;^{208}Pb/^{206}Pb$) were nearly constant during 300 yrs past than 1930, but increased up to twice in concentration and as much as 3.41% (1.70%) after 2000. On the other hand, residual Pb concentrations were nearly constant for past 400 yrs. The accumulation rates of anthropogenic Pb in the basin area were in the range of $3.1-3.5mg/m^2/yr$, which were similar levels to total atmospheric Pb deposition fluxes from 1990s to the present. In the slope area, more increase of anthropogenic Pb accumulation than the levels expected from mass accumulation rate could be found after the middle of 1990s. From the detailed evaluation for the temporal and spatial variation of accumulation rate and isotope ratios of anthropogenic Pb, we proposed probable sources and pathways of anthropogenic Pb. Pb emmision by coal burning from the China and Korea initiated the accumulation of anthropogenic Pb in the sediments of East/Japan Sea from 1930s. The accumulation of Pb increased by the addition of anti-nocking agents from both countries untill the beginning of 1990s, but from the middle of 1990s to the present, the phase-out of gasoline additives and the rapid increase of coal burning from the China maintained the atmospheric Pb levels in the Ulleung basin nearly similar to before. However, the local sources within this basin might take an important role in the rapid increase of anthropogenic Pb accumulation in slope areas from the middle of 1990s.

Assessment and Calibration of Ultrasonic Velocity Measurement for Estimating the Weathering Index of Stone Cultural Heritage (석조문화재의 풍화지수 산정을 위한 초음파속도의 평가 및 보정)

  • Lee, Young-Jun;Keehm, Young-Seuk;Lee, Min-Hui;Han, June-Hee;Kim, Min-Su
    • Journal of the Korean earth science society
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    • v.33 no.2
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    • pp.126-138
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    • 2012
  • Ultrasonic method is widely used for the evaluation of weathering index and of degree of deterioration because it is easily applicable $in$ $situ$. The basic idea of the method is that the ultrasonic velocity decreases as a rock is being weathered. Thus, the difference of ultrasonic velocities between fresh rock and weathered rock indicates the degree of weathering. In this method, the ultrasonic velocity of fresh rock is assumed to be 5,000 m/s. However, this assumption can cause significant errors in estimating weathering index, especially in case that those rocks of the same type have a wide range of ultrasonic velocities such as in Korea. Therefore, we obtained twenty rock specimens and sixty core samples commonly used for stone cultural heritages in Korea, and measured ultrasonic velocities. From the results, we found that the ultrasonic velocities of the same rock type, granite samples range from 3,118 to 5,380 m/s, and that the estimated weathering index can be highly biased if we use the fixed value of 5,000 m/s. We created a database (DB) by combining the measurement data and reported it. We also measured ultrasonic velocities by direct and indirect methods to quantify the calibration coefficient for each sampling site. We found that the calibration coefficients vary widely from site to site (1.31-1.76). Other factors, such as operator bias and temperature did not show any significant effect on errors in ultrasonic velocity measurements. Lastly, we applied our ultrasonic velocity DB and calibration coefficients to a stone cultural heritage, Bonghwang-ri Buddha statue. Our estimation of the weathering index was 0.3, 0.1 smaller than that by conventional method. The degree of deterioration was also different, "moderately weathered", while conventional method gave "highly weathered". Since other independent studies reported that the degree of deterioration of the Buddha statue was "moderately weathered", our estimation seems to be more accurate. Thus our method can help accurately evaluate the weathering index and the conservation planning for a stone cultural heritage.

Process of change and cause of the perform a play on the stage of the Duhak nongak(農樂) in Jecheon (제천시 두학동 상풍마을 농악(農樂)의 변천 과정과 연희화(演戱化))

  • Choi, Ja-Un
    • (The) Research of the performance art and culture
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    • no.32
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    • pp.371-397
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    • 2016
  • The function of the Duhak nongak(農樂) in Jecheon consist of Ceremony, Labor, and Entertainment. Before the commemorative rites for village god village people beat a small gong. This is a evidence of the drive away evil spirits in New Year's Eve of the lunar year. Before harden house site village peoples beat musical instrument noisily. In order to press hard the god of the earth they play musical instrument. Musical instrument not a simple musical instrument, but a purify and wish tool. When weeding a rice paddy Durae organized in Sangpung village. Durae are less effective than communal sharing of labor in weeding effect. Nonetheless, Nongak carried out core function in Durae. In order to participate Nonngak concours, peoples made a Pangut. From independence to 1970s people combine traditional nongak and Pangut. Since then village people played Pangut. From 1990s Pangut was played by Duhak Nonngak Preservation Association. Through the participation Nonngak concours, Duhak nongak was regrouped. Finally this nongak prepared Taeguk-jin, Snail-jin, Cross-jin, Sabang-jin, Sanggyeonrae Bans anggyeonrae-jin, Palbang-jin, Rope making and individual play. Duhak Nonngak promptly met the needs of the times. So, they could play Pangut. The feature of the Duhak Nonngak is that active cognition, highly skilled musician a patron and scouting a competent leader.

A Comparison of Incarnation Theology in Christianity and Daesoon Jinrihoe (基督宗教与大巡真理会的「道成肉身」思想之比较)

  • Gao, Mingwen
    • Journal of the Daesoon Academy of Sciences
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    • v.34
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    • pp.323-351
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    • 2020
  • The purpose of this paper is to reveal how Christian ideas are indicative of Theocentricity (God-centeredness) whereas Daesoon Jinrihoe ideas are indicative of anthropocentrism (human-centeredness). This task will be accomplished through comparing incarnation theology from the Bible and The Canonical Scripture. Both Christianity and Daesoon Jinrihoe affirm that there is another world above the human world that cannot be touched by human sense organs. And they both acknowledge a supreme deity who exists in that above world. Furthermore, they share the notion that the supreme deity came into the human world after being born from a woman. Where they depart is that in Christianity, this belief refers to Jesus, the one who was born in Bethlehem more than 2,000 years ago, whereas in Daesoon Jinrihoe, it is instead believed to be Kang Jeungsan (secular name: Kang Il-Sun) who was born in Gaekmang Village in Korea more than 100 years ago. The Christian God came to the human world as an atonement for humanity and died on the cross; The God of Daesoon Jinrihoe came to the human world to help mankind settle all enmities. To this end, he traveled through the realms of Heaven, Earth, and Humanity, to recalibrate the faulty Degree Numbers. The sin mentioned in Christianity means treachery against the supreme deity. It is implied that sin is not tolerated in the world of God. Due to this, the first man, Adam, was driven out of Eden after betraying God, and afterwards, there came to be an infranchissable boundary between the world of God and the world of man. By way of comparison the faulty Degree Numbers, mentioned in Daesoon Jinrihoe, were produced naturally. In other words, the faulty Degree Number existed not only in the human world, but also in the world of divinities, and those two worlds not only interact but also affect each other. Therefore, it can be said that the two worlds of Christianity are worlds in which order and systems are completely different, and that the two worlds of Daesoon Jinrihoe are worlds that operate under the same order and systems. Both explain via this two-part division to emphasize one part as more important than the other. Christianity regards the world of God as the ultimate source and ultimate concern of the human world and emphasizes the absolute faith and worship of God is the highest value in life. But Daesoon Jinrihoe, on the other hand, argues that the human world determines the value of the divine world, and that the co-prosperity of man and his surroundings are the core values of the human era (The Era of Human Nobility). Therefore, the root cause of Christianity's theocentricity is that among the two worlds that are completely cut off from one another, they believe in God's world as the ultimate source and purpose of the human world. The root cause of Daesoon Jinrihoe's anthropocentrism is that among the two worlds that interact and influence each other, they believe the human world determines the meaning of the divine world.