• Title/Summary/Keyword: D.O.F.

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Improve of Efficiency of Multi D.O.F Spherical Motor Through the Reduction of Eddy Current Loss (다자유도 구형 구동 모터의 와전류 손실 저감을 통한 효율 향상 연구)

  • Hong, Kyung-Pyo;Kim, Yong;Jang, Ik-Sang;Lee, Ho-Joon;Kang, Dong-Woo;Won, Sung-Hong;Lee, Ju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.1
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    • pp.50-56
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    • 2012
  • The Multi D.O.F spherical motor can drive rotating as well as tilting three degree of freedom with one motor. Existing three degree of freedom to drive with three motors that are connected by gears and belts, that will be too large size and big loss at gears and belts. So Reducing system size and improving efficient is using the Multi D.O.F spherical motor in three degree of freedom systems. For this reason, efficiency of Multi D.O.F spherical motor is one of the important performance indiccators. In this paper presented that how to improve the efficiency of the Multi D.O.F spherical motor. The fist of method is using the stator iron core's material with high permeability and resistivity for reducing the eddy current loss. However, it was the disadvatages of motor-making and economic. So author propose the resonable method of reducing the eddy current loss in the stator iron core. That is using the rotor with double-air gap.

HYPERSENSITIZATION FOR ASTRONOMICAL PHOTOGRAPHIC PLATES: IIIa-J, IIIa-F, 103a-O, 103a-D and IIa-O PLATES (천체 사진 건판의 초증감 처리 : IIIa-J, IIIa-F, 103a-O, 103a-D 및 IIa-O 건판)

  • Jeon, Yeong-Beom;Sim, Gyeong-Jin
    • Publications of The Korean Astronomical Society
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    • v.8 no.1
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    • pp.119-136
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    • 1993
  • Optimum hypering conditions are found for IIIa-J, IIIa-F, 103a-O, 103a-D, and IIa-O plates using hypersensitization machine in KAO. For every experimental plate we get speed gain, fog increment, signal to noise ratio and relative DQE according to hypering time and temperature. The hypersensitization method is baking with 8% hydrogen mixed gas. For IIIa-J, 103a-O, and 103a-D plates treated $65^{\circ}C$, 3 hours baking, the speed gains arc increased by about 10 times, 2 times, and 2 times compared to untreated plates, respectively. The fogs are increased by 0.08, 0.10, and 0.08, respectively. For IIIa-F, IIa-O plates treated $65^{\circ}C$, 2 hours baking, the speed gains are increased by about 4.7 times and 1.8 times compared to untreated plates, respectively. The fogs are increased by 0.15 and 0.04, respectively.

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A Study on Combustion Characteristics of Hybrid Rocket with the Variation of L/D ratio (하이브리드 로켓의 L/D 비 변화에 따른 연소특성 연구)

  • Kim Soo-jong;Kim Jin-kon;Lee Seung-chul;You Woo-jun;Lee Jung-pyo
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • v.y2005m4
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    • pp.83-87
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    • 2005
  • In this paper, the combustion characteristics of a hybrid propulsion system were studied with various L/D(length vs diameter) ratio of the single port type solid fuel. Experiments of L/D ratio change were performed for 2 cases with the fixed grain port diameter and fuel length respectively. For the First case, results show that there are no large variation for regression rates as the L/D ratio changes. And as the L/D ratio increases, the O/F ratio and thrust tends to increase. For the Second case, there are no large change for O/F ratio and thrust as L/D ratio changes. On the other hand, as the L/D ratio decreases, only the regression rate tends to increase.

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Effects of flower removal on Growth and Content of essential oil in Atractylodes macrocephala Koidz (화기제거가 백출(Atractylodes macrocephala Koidz)의 생육 및 정유 함량에 미치는 영향)

  • 김수용;권오흔;조지형;임재하
    • Korean Journal of Plant Resources
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    • v.14 no.2
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    • pp.152-156
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    • 2001
  • This study was conducted to investigate the flower organ removal effect on Atractylodes macrocephala Koidz which was introduced from China. The results were summarized as follows; The plant height of Flower Organ Cutting(F.O.N.C.) treatment short by 1.7∼2.5 cm compared to Flower Organ Non-Cutting(F.O.N.C.) treatment. But number of stem and stem diameter of F.0.C treatment were similar to that of F.O.N.C. treatment. The fresh weight of above-ground part of F.O.N.C. treatment was decreased 48∼60% compare to F.O.C. treatments. The later was period of F.O.C., the higher was fresh weight of above-ground part. The growth of underground part was more F.O.C. at July 15 and Aug. 20 treatments than F.O.N.D treatment. The dry rhizome yield of F.O.C. at July 15 treatment was increased 40% compare to F.O.N.D treatment. Essential oil content of F.O.C. at July 15 treatment was increased 12% compare to F.O.N.D treatment.

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An Analysis on the Relationship to Input/Output factor and Evaluation Grade in Nuclear R&D Program (연구개발사업의 투입.산출요소 및 연구결과 평가의 상호관계 분석 - 원자력중장기연구개발사업을 중심으로-)

  • Hong Jeong-Jin;Won Byeong-Chul;Yang Maeng-Ho
    • Proceedings of the Korea Technology Innovation Society Conference
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    • 2004.05a
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    • pp.48-56
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    • 2004
  • To perform R&D program, it is necessary to invest input factor(I/F). And these factor are converted to output factors(O/F) at the end of R&D program. Pee. reviewers evaluate output factors and produce evaluation grades(E/G). This paper try to analyze the relationship to I/F, O/F and E/G, According to the analysis results, the relation between I/F and E/G is as weak as the relation between O/F and E/G. The strength of relationship is relatively very strong in the relation between I/F and O/F

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Luminescence characterization of $EU^{3+}$ and $Bi^{3+}$ co-doped in ${Y_2}{SiO_5}$ red emitting phosphor by solid state reaction method (고상 반응법으로 합성한 ${Y_2}{SiO_5}:\;EU^{3+}$, $Bi^{3+}$ 적색 형광체의 발광 특성)

  • Moon, J.W.;Song, Y.H.;Park, W.J.;Yoon, D.H.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.19 no.1
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    • pp.15-18
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    • 2009
  • To enhance near UV-visible absorption region and to applied phosphor convert-white LEOs (PC-WLEDs), a red phosphor composed of ${Y_2}{SiO_5}:\;EU^{3+}$, $Bi^{3+}$ compounds was prepared by the conventional solid-state reaction. The photoluminescence (PL) shown that samples were excited by near UV light 395 nm for measurement of PL spectra. Emission spectra of samples have shown red emissions at 612 nm ($^5D_0{\to}^7F_2$). The enhanced near $UV{\sim}$ visible excitation spectrum with a broad band centered at 258 nm and 282 nm originated in the transitions toward the charge transfer state (CTS) due to the $Eu^{3+}-Bi^{3+}-O^{2-}$ interaction. The other excitation band at $350\;nm{\sim}480\;nm$, corresponding to the transitions $^7F_0{\to}^5L_9$ (364 nm), $^7F_0{\to}^5G_3$ (381 nm), $^7F_0{\to}^5L_6$ (395 nm), $^7F_0{\to}^5D_3$, (415 nm) and $^7F_0{\to}^5D_2$ (466 nm), occurred due to enhanced the f-f transition increasing $Bi^{3+}$ and $Eu^{3+}$ ions. The PL intensity increased with increased as concentration of $Bi^{3+}$ and the emission intensity becomes with a maximum at 0.125 mol.

Construction of a macro plane stress triangle element with drilling d.o.f.'s (드릴링 자유도를 가진 매크로 삼각형 요소를 이용한 평면 응력 해석)

  • 엄재성;김영태;이병채
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.886-889
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    • 2004
  • A simple macro triangle with drilling d.o.f.'s is proposed for plane stress problems based on IET(Individual element test) and finite element template. Three-node triangular element has geometrical advantages in preprocessing but suffers from bad performance comparing to other shapes of elements -especially quadrilateral. Main purpose of this study is to construct a high-performance linear triangular element with limited supplementary d.o.f.'s. A triangle is divided by three sub-triangles with drilling d.o.f.'s. The sub-triangle stiffness come from IET passing force-lumping matrix, so this assures the consistency of the element. The macro element strategy takes care of the element‘s stability and accuracy like higher-order stiffness in the F.E. template. The resulting element fits on the uses of conventional three-node. Benchmark examples show proposed element in closed form stiffness from CAS (Computer algebra system) gives the improved results without more computational efforts than others.

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Pyroelectric Infrared Sensors using (Pb,La)TiO3/LiTaO3/(Pb,La)TiO3 Multilayer Ferroelectric Thin Films ((Pb,La)TiO3/LiTaO3/(Pb,La)TiO3 다층 강유전 박막을 이용한 초전형 적외선 센서)

  • Sung, Se-Kyoung;Lee, Du-Hyun;Choi, Hyek-Hwan;Lee, Myoung-Kyo;Kwon, Tae-Ha
    • Journal of Sensor Science and Technology
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    • v.11 no.4
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    • pp.247-253
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    • 2002
  • For fabrication of the pyroelectric IR sensor $(Pb,La)TiO_3(PLT)$/$LiTaO_3$/(LTO)/PLT ferroelectric thin films was deposited by rf magnetron sputtering followed by rapid thermal annealing and the crystallinity as a function of annealing temperature and time was investigated. Permittivity and dielectric loss factor of ferroelectric thin films as a function of c-axis preffered orientation was measured. Also pyroelectric coefficient of ferroelectric thin films with largest c-axis preffered orientation was measured and obtain figure of merit of voltage response($F_V$) and detectivity($F_D$). In this case $F_V$, $F_D$ was $5.63{\times}10^{-10}\;C{\cdot}cm/J$, $1.98{\times}10^{-8}\;C{\cdot}cm/J$, respectively.

Characteristics of the NO/$N_2O$ Nitrided Oxide and Reoxidized Nitrided Oxide for NVSM (비휘발성 기억소자를 위한 NO/$N_2O$ 질화산화막과 재산화 질화산화막의 특성에 관한 연구)

  • 이상은;서춘원;서광열
    • Journal of the Korean Vacuum Society
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    • v.10 no.3
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    • pp.328-334
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    • 2001
  • The characteristics of $NO/N_2O$ nitrided oxide and reoxidized nitrided oxide being studied as super thin gate oxide and gate dielectric layers of nonvolatile semiconductor memory(NVSM) was investigated by dynamic secondary ion mass spectrometry(D-SMS), time-of-flight secondary ion mass spectrometry(ToF-SIMS), and x-ray photoelectron spectroscopy (XPS). The specimen was annealed in $NO/N_2O$ ambient after initial oxide process. The result of D-SIMS exhibits that the center of nitrogen exists at the initial oxide interface and the distribution of nitrogen is wider in the annealing process with $N_2O$ than with NO annealing process. For investigating the condition of nitrogen that exists within the nitrided oxide, ToF-SIMS and XPS analysis were carried out. It was shown that the center of nitrogen investigated by D-SIMS was expected the SiON chemical bonds. The nitrogen near the newly formed reoxide/silicon substrate interface was appeared as $Si_2NO$ chemical bonds, and it is agreed with the distribution of SiN and $Si_2NO$ species by ToF-SIMS.

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Saponins from the Roots of Pulsatilla koreana

  • Kang, Sam-Sik
    • Archives of Pharmacal Research
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    • v.12 no.1
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    • pp.42-47
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    • 1989
  • From the roots of Puisatiila koreana, three monodesmosides(pulsatilla saponins A, B and D) and two bisdesmosides(pulsatilla saponins F and H) were isolated. The structure of these saponins have been determined as hederagenin 3-O-${\beta}$-L-rhamnopyranosyl($1{\to}2$)- ${\alpha}$-L-arabinopyranoside(A), hederagenin 3-O-${\beta}$-D-glucopyrano syl($1{\to}4$) - ${\alpha}$-L-arabinopyranoside(B), hederagenin 3-O- ${\alpha}$-L-rhamnopyranosyl ($1{\to}2$)-[${\beta}$-D-glucopyranosyl($1{\to}4$]-${\alpha}$-L-arabinopyranoside(D), 3-O-${\alpha}$-L-rhamnopyranosyl($1{\to}2$)-{${\alpha}$-L-arabinopyranosyl hederagenin 28-O-${\alpha}$-L-rhamnopyrano syl($1{\to}4$)-${\beta}$-D-glucopyrano syl($1{\to}6$)-${\beta}$-D-glucopyranosyI ester (F) and 3-O-${\alpha}$-L-rhamnopyranosyl($1{\to}2$)-[${\beta}$-D-glucopyranosyl($1{\to}4$)]- ${\alpha}$-L-arabinopyranosyl hederagenin 28-O-${\alpha}$-L-lharnnopyranosyl($1{\to}4$)-${\beta}$-D-glucopyranosyl($1{\to}6$)-${\beta}$-D-glucop yranosyl ester(H) on the basis of chemical and spectral studies. Pulsatilla saponin B is the first report of its presence in plants but saponins A, D, F, and H have recently been isolated from the same genus p. cernua.

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