• 한국수학교육학회지시리즈A:수학교육
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• 제46권1호
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• pp.81-96
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• 2007

This study was conducted to investigate the possibility of teaching tessellations' mathematical principles in elementary school mathematics. A survey was carried out and the two hours of the instructional experiment were developed for this study triangular tessellation activity and rectangular tessellation activity. Six fifth graders from W elementary school participated voluntarily in the instructional experiment. It was shown from the survey that teachers and students both know what the tessellation is, but they don't know what the mathematical principles really are in the tessellation. This is because they have just done the covering up-activities in class. It was seen from the instructional experiments that even ordinary students were able to understand the mathematical principles of the tessellation if teachers could throw the suitable focusing questions like 'how to move the rectangles making sides equal' and 'how to gather vertexes making angle $360^{\circ}$'. Furthermore, it is desirable to teach the rectangular tessellation prior to the triangular tessellation since the rectangular tessellation is more easy to deal with than the triangular tessellation.

• Journal of Acupuncture Research
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• 제20권3호
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• pp.194-208
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• 2003

Objective : Recently, many studies have showed the evidences of the effect of acupuncture treatment through scientific methods. We performed electro-acupuncture on Taixi(K3) and observed the change of brain activity using fMRI. Methods : To see the effect of electro-acupuncture stimulation on Taixi(K3), the experiment was carried out on twelve healthy volunteers, using the gradient echo sequence with the 3.0T whole-body fMRI system(ISOL). After the needle insertion on K3, 2 Hz of electric stimulation was given for 30 seconds, repeated five times, with 30 seconds' intervals. Result & Conclusions : Unilateral electro-acupuncture stimulation on K3 increased the brain activity in Brodman Area 8, 6, 9, 13, 21, 22, 38, 40, 43, 2, 5, 10, 20, 24, 32, 34, 37, 39, 41, 42. and decreased the brain activity in Brodman Area 9, 13, 38, 22, 31, 3, 6, 10, 21, 25, 29, 30. Group Averaged Brain activity induced by Unilateral Electro-acupuncture Stimulation on K3 was increased in Brodman Area 10, 22, 42, 43, 44 and was decreased inn Brodman Area 6 and pyrogen test of Bee venom. Bilateral electro-acupuncture stimulation on k3 increased the brain activity in Brodman Area 22, 3, 19, 4, 13, 17, 21, 41, 42, 2, 5, 6, 7, 18, 23, 29, 30, 31, 40 and decreased the brain activity in Brodman Area 18, 6, 39, 4, 13, 2, 10, 19, 36, 40, 45, 46, 47. Group Averaged Brain activity induced by Bilateral Electro-acupuncture Stimulation on K3 was increased in Brodman Area 22, 13, 4, 3, 29, 38, 43 and was decreased in Brodman Area 18, 3, 19, 22, 39. Motor Stimulation activated Brodmann Area 6, 43, 18.

• 한국콘텐츠학회논문지
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• 제20권8호
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• pp.618-627
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• 2020

본 연구는 청소년의 활동역량이 최근 대두되는 이슈로서 청소년 활동역량, 진로결정 자기효능감, 부모진로 지지와의 구조적 관계에 대하 규명하고자 한다. 본 연구는 천안 및 세종지역에 소재하는 고등학교 청소년 437명을 대상으로 설문조사를 실시하였고, 자료 분석은 SPSS 23.0, AMOS 23.0 프로그램을 사용하였다. 본 연구의 결과는 다음과 같다. 첫째, 고등학생의 청소년 활동역량은 부와 모의 진로지지에 모두 유의한 영향을 미치는 것으로 나타났다. 둘째, 고등학생의 부와 모의 진로지지는 진로결정 자기효능감에 모두 유의한 영향을 미치는 것으로 나타났다. 셋째, 고등학생의 청소년 활동역량은 진로결정 자기효능감에 유의한 영향을 미치는 것으로 나타났다. 넷째, 고등학생의 청소년 활동역량과 진로결정 자기효능감의 관계에서 부모진로지지는 매개효과가 있음을 검증하였다. 본 연구는 스스로 지니고 있는 청소년 활동역량이 청소년들의 가장 큰 고민인 진로결정 자기효능감과 관련이 있을 수 있다는 관점에서 새로운 문제제기를 했다는 것에 의의가 있다.

• Journal of Ginseng Research
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• 제38권2호
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• pp.154-159
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• 2014

Background: This study was carried out to investigate the effect of the steaming process on chemical constituents, free radical scavenging activity, and antiproliferative effect of Vietnamese ginseng. Methods: Samples of powdered Vietnamese ginseng were steamed at $120^{\circ}C$ for various times and thei extracts were subjected to chemical and biological studies. Results: Upon steaming, contents of polar ginsenosides, such as Rb1, Rc, Rd, Re, and Rg1, were rapidly decreased, whereas less polar ginsenosides such as Rg3, Rg5, Rk1, Rk3, and Rh4 were increased as reported previously. However, ocotillol type saponins, which have no glycosyl moiety at the C-20 position, were relatively stable on steaming. The radical scavenging activity was increased continuously up to 20 h of steaming. Similarly, the antiproliferative activity against A549 lung cancer cells was also increased. Conclusion: It seems that the antiproliferative activity is closely related to the contents of ginsenoside Rg3, Rg5, and Rk1.

• 대한예방한의학회지
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• 제4권1호
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• pp.144-151
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• 2000

This study was carried out to evaluate cytotoxic effects of Houttuynia cordata Thunberg extracts on murine leukemia tumor cell lines. Disruptions in cell organelles were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazol iumbromide (MMT) assay. The comparison of $IC_{50}$ values of Houttuynia cordata Thunberg extracts on $L1210,\;P388D_1$ and Vero cell lines showed that the methanol extract of Houttuynia cordata Thunberg indicated the most antitumor activity in the MTT assay. In order to develop a antimicrobial agent, dried Houttuynia cordata Thunberg was extracted with several solvents, and then antimicrobial activity was investigated. The minimal inhibitory concentration (MIC) of the extracted substance against microorganisms were also examined. Antimicrobial activity of amocla and ketoconazole as references was compared to those of other solvent extracts such as $H_2O$, n-hexane, chloroform, ethyl acetate ethanol and methanol. The antimicrobial activity of all extracts from the sample had growth inhibition activity against gram-negative bacteria, yam-positive bacteria and fungi $(MIC,\;>\;200\;{\mu} g/ml)$. These results suggest that the methanol soluble extract of Houttuynia cordata Thunberg may be a valuable choice for the studies on the treaeent of murine leukemia tumor cell lines and antimicrobial agents.

• The Korean Journal of Physiology
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• 제12권1_2호
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• pp.7-13
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• 1978

The present study was undertaken to investigate effects of ethanol extracts of acorn (QAEE) on arterial blood Pressure and respiration, to find out the mechanism of depressor activity of QAEE,. add to determine lethal dosages of QAEE in rabbits and dogs. The results obtained were as follows: 1) After administration of 20 mg/Kg, 30 mg/kg, and 40 mg/kg of QAEE into rabbits the maximum depressor responses observed were respectively $16.3{\pm}1.4\;mmHg$, $28.7{\pm}2.0\;mmHg$ and $45.6{\pm}3.1\;mmHg$, while mean depressor responses following administration of 40mg/kg, 60mg/kg and 80mg/kg of QAEE into dogs were $32.2{\pm}1.6\;mmHg$, $39.5{\pm}1.5\;mmHg$, and $47.0{\pm}1.6\;mmHg$ respectively 2) Genenally depressor responses increased in proportion to dosage of QAEE administered whereas at same dosage of QAEE depressor responses were greater in rabbit than in dog. 3) It is suggested that depressor activity of QAEE resides mostly in its activity to activate vagus nerves and partly in Its activity to block beta-rceptors. 4) The lethal dosages of QAEE were 50 mg/kg to 60mg/kg for rabbi hue 90mg/kg to 100 mg/kg for dogs. 5) After QAEE administration respiratory rates were generally increased in the rabbit and the dog.

• Journal of Preventive Medicine and Public Health
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• 제39권4호
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• pp.325-330
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• 2006

Objectives: The aims of this study were to examine the level of airborne fungi and environmental factors in Seoul metropolitan subway stations and to provide fundamental data to protect the health of subway workers and passengers. Methods: The field survey was performed from November in 2004 to February in 2005. A total 22 subway stations located at Seoul subway lines 1-4 were randomly selected. The measurement points were subway workers' activity areas (station office, bedroom, ticket office and driver's seat) and the passengers' activity areas (station precincts, inside train and platform). Air sampling for collecting airborne fungi was carried out using a one-stage cascade impactor. The PM and CO2 were measured using an electronic direct recorder and detecting tube, respectively. Results: In the activity areas of the subway workers and passengers, the mean concentrations of airborne fungi were relatively higher in the workers' bedroom and station precinct whereas the concentration of particulate matter, $PM_{10}\;and\;PM_{2.5}$, were relatively higher in the platform, inside the train and driver's seat than in the other activity areas. There was no significant difference in the concentration of airborne fungi between the underground and ground activity areas of the subway. The mean $PM_{10}\;and\;PM_{2.5}$ concentration in the platform located at underground was significantly higher than that of the ground (p<0.05). Conclusions: The levels of airborne fungi in the Seoul subway line 1-4 were not serious enough to cause respiratory disease in subway workers and passengers. This indicates that there is little correlation between airborne fungi and particulate matter.

• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.49-54
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• 2003

TiO₂nanoparticles were synthesized using the metallorganic chemical vapor deposition process. Particles with and without metal ion dopants were obtained. X-ray photoelectron and energy dispersive X-ray spectroscopic measurements confirmed the stoichiometry of the TiO₂nanoparticles. X-ray diffraction patterns showed a polycrystalline anatase structure of TiO₂. Transmission electron microscopy revealed that these particles are of nanoscale dimensions. Exact particle size and size distribution analyses were carried out by dynamic light scattering. The average particle size was determined to be 22 nm. The nanosize particles provided large surface area for photocatalysis and a large number of free surface-charge carriers, which are crucial for the enhancement of photocatalytic activity. To improve the photocatalytic activity, metal ions, including transition metal ions $(Pd^{2+},\;Pt^{4+},\;Fe^{3+})$ and lanthanide ion $(Nd^{3+})$ were added to pure TiO₂nanoparticles. The effects of dopants on photocatalytic kinetics were investigated by the degradation of 2-chlorophenol under an ultraviolet light source. The results showed that the TiO₂nanoparticles with the metal ion dopants have higher photocatalytic activity than undoped TiO₂. The $Nd^{3+}$ ion of these dopant metal ions showed the highest catalytic activity. The difference in the photocatalytic activity with different dopants is related to the different ionic radii of the dopants.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.142.2-142.2
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• 2013

The effect of substrate on catalytic activity of CO oxidation with transition metal Platinum nanoparticles on doped and undoped TiO2 was investigated. Titanium dioxide was doped chemically with non-metal anions including nitrogen and fluorine. Undoped TiO2 was synthesized via simple conventional sol-gel route. Thin films of titania were developed by spin coating technique and the characterization techniques SEM, XRD, UV-Vis Absorption Spectroscopy and XPS were carried out to examine the morphology of films, crystal phase, crystallites, optical properties and elemental composition respectively. XPS analysis from doped TiO2 confirmed that the nitrogen site were interstitial whereas fluorine was doped into TiO2 lattice substitutionally. Catalytic activity systems of Pt/doped-TiO2 and Pt/undoped-TiO2 were fabricated to reveal the strong metal-support interaction effect during catalytic activity of CO oxidation reactions. By arc plasma deposition technique, platinum nanoparticles with mean size of 2.7 nm were deposited on the thin films of doped and undoped titanium dioxide. The CO oxidation was performed with 40 Torr CO and 100 Torr O2 with 620 Torr He carrier gas. Turn over frequency was observed two to three folds enhancement in case of Pt/doped TiO2 as compared to Pt/TiO2. The electronic excitation and the oxygen vacancies that were formed with the doping process were the plausible reasons for the enhancement of catalytic activity.

• The Journal of Korean Physical Therapy
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• 제34권4호
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• pp.175-180
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• 2022

Purpose: Leg length discrepancy causes the posture deformation, gait asymmetry, and lower back pain. The purpose of this study is to investigate the correlation among functional leg length discrepancy (FLLD), muscle activity, muscle contraction onset time and vertical ground reaction force (vGRF) during simple lifting task. Methods: Thirty-nine subjects participated in this study. FLLD was measured from the umbilicus to medial malleolus of left and right leg using a tape. The subjects performed to lift a 10 kg box from the floor to chest. The muscle activity and muscle contraction onset time of rectus abdominis, erector spinae and rectus femoris was measured using EMG system and vGRF was measured by two force plate. Pearson correlation was used to fine out the correlation among FDDL, muscle activity, muscle contraction onset time and vGRF during simple lifting task. Results: Correlation between FLLD and difference of muscle activity of short-long side was very high (r>0.9) during simple lifting task. Correlation between FLLD and difference of muscle contraction onset time of short-long side was very high (r>0.9) during simple lifting task. And correlation between FLLD and difference of vGRF of short-long side was high (r>0.7) during simple lifting task. Conclusion: This study suggests that there is high correlation between FLLD and muscle activity, muscle contraction onset time, and ground reaction force during simple lifting task. Therefore, FLLD could negatively affect the postural balance.