• Title/Summary/Keyword: perfect reflection

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Development and Verification of Static-Dynamic Cone Penetrometer (정동적 콘관입실험 장비의 개발과 검증)

  • Bae, Myeong-Ho;Yu, Jung-Dong;Kim, Ju-Han;SaGong, Myung;Lee, Jong-Sub
    • Journal of the Korean Geotechnical Society
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    • v.27 no.1
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    • pp.77-86
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    • 2011
  • The advanced geotechnical information has been required to determine the accurate design parameters for complex construction. However, the Standard Penetration Test (SPT), which has low reliability, has been used to estimate the subsurface condition in the field. The objective of this paper is development and application of the Static-Dynamic penetrometer, which detects the resistances in soft clay, sand and rock. The energy losses according to the rod connection methods (perfect or non-perfect connection, and number rods) are experimentally evaluated. The reflection and transmission ratios are used to investigate the energy loss by a simulation. The static-dynamic cone penetrometer, in which the accelerometers and strain gauges are installed on the cone tip and the rod head, is used to estimate the energy loss during penetration by impacts. The experimental and simulation studies show that the transferred energy through rods with non-perfect connection dramatically decreases. Furthermore, the transferred energy on the rod head is not the same as that on the cone tip. This study demonstrates that the energy loss should be evaluated on the cone tip.

Nonlinear Analysis of RC Beams Considering Fixed-End Rotation due to Bond-Slip (부착슬립에 의한 강체변형을 고려한 철근콘크리트 보의 비선형해석)

  • Kwak Hyo-Gyoung;Kim Sun-Pil
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2005.04a
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    • pp.456-463
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    • 2005
  • An analytical procedure to analyze reinforced concrete (RC) beams subject to monotonic loadings is proposed on the basis of the moment-curvature relations of RC sections. Unlike previous analytical models which result the overestimation of stiffnesses and underestimation of structural deformations induced from ignoring the shear deformation and assuming perfect-bond condition between steel and concrete, the proposed relation considers the rigid-body-motion due to anchorage slip at the fixed end. The advantages of the proposed relation, compared with the previous numerical models, are on the promotion in effectiveness of analysis and reflection of influencing factors which must be considered in nonlinear analysis of RC beam by taking into account the nonlinear effects into the simplifying moment-curvature relation. Finally, correlation studies between analytical and experimental results are conducted to establish the applicability of the proposed model to the nonlinear analysis of RC structures.

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Establishment of Equivalent Circuit Model about Planar-type Inductively Coupled Plasma Sources (평판형 유도결합 플라즈마원의 등가회로 모델 정립)

  • Lee Jong-Kyu;Kwon Deuk-Chul;Yu Dong-Hun;Yoon Nam-Sik
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.5
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    • pp.218-223
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    • 2005
  • Impedance matching characteristics of planar type inductively coupled plasma sources are investigated utilizing the previously reported two-dimensional theory[1] of the anomalous skin effect. Two types of matching networks are considered, and the values of the circuit elements are expressed as functions of various reactor parameter. Also, two cases of perfect and imperfect matching conditions are considered and the functional dependence of the values of matching capacitance and reflection coefficient on the various reactor parameters are investigated using the present circuit model.

A New Calibration Algorithm of a Five-Hole Pressure Probe for Flow Velocity Measurement (유동속도계측을 위한 5공압력프로브의 새로운 교정 알고리듬)

  • Kim, J.K.;Oh, S.H.
    • Journal of Power System Engineering
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    • v.12 no.4
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    • pp.18-25
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    • 2008
  • This paper investigated the new calibration algorithm of a straight-type five-hole pressure probe necessary for calculating three-dimensional flow velocity components. The new data reduction method Includes a look-up, a geometry transformation such as the translation and reflection of nodes, and a binary search algorithm. This new calibration map was applied up to the application angle, ${\pm}55^{\circ}$ of a probe. As a result, this data reduction method showed a perfect performance without any kind of interpolation errors In calculating yaw and pitch angle from the calibration map.

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Design of Transparent Electromagnetic Absorbing Structure for Stealth Aircraft Canopy (스텔스 전투기 캐노피를 위한 투명 전자파 흡수구조 설계)

  • Hong, Ic-Pyo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.18 no.4
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    • pp.369-375
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    • 2015
  • In this paper, transparent circuit analog radar absorbing structure with angular stability for stealth aircraft canopy was proposed and designed. To obtain wideband electromagnetic absorption, optical transparency and smaller thickness, we proposed the novel FSS(Frequency Selective Surface) for X-band and implemented the resistive FSS and PEC(Perfect Electric Conductor) plane using ITO(Indium Thin Oxide) coating with optical transmissivity of 90 %. Reflection loss characteristics for different incident angles of both TE(Transverse Electric) and TM(Transverse Magnetic) polarizations are presented through simulations. We then fabricated the proposed structure to verify the simulation results. The comparisons between the simulation and measured results show good agreements. The results also show that the proposed radar absorbing structure can provide better frequency stability for different incidence angles and polarizations as well as optical transparency. We can apply this proposed structure to the canopy of stealth aircraft and other stealth applications for visible transparency.

A Study on Illusion of Digital Image (디지털영상의 환상성에 관한 연구)

  • Choi, Won-Ho;Kim, Cheeyong
    • Journal of Korea Multimedia Society
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    • v.16 no.5
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    • pp.647-656
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    • 2013
  • The desire of humankind that longed for reappearance of visual makes progress within the development of linear history. The directing point at the moment was the 'eye'. Upon completion of setting the aiming point, visual image attempts reflection of main agent beyond reappearance of it and, by extension, aimed to visualize desire which was latent in the instance of main agent. It was able to experience a fantasy in paintings, photos and movies as a stage of desire, of course. Digital, however, suggested a new phasis in creating a fantasy world. This study aimed to research the fantastic nature in digital image that a fantastic image is created as a reflection of both independence and unconsciousness. As a result of research, this study revealed that digital image, as a channel that image and imaginative desire which were saved in id, is created as a perfect stage on the basis of verisimilitude, granting an experience toward realization of desire to a main agent raising id which was repressed by the ego and superego to the surface.

A Design of Multi-band Antenna using asymmetric Bow-tie structure (비대칭 보우 타이 구조를 이용한 다중 대역 안테나 설계)

  • Jang, Jeong-Seok;Kim, Dae-Woong;Choi, Yong-Gyu;Hong, Ui-Seok
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.9 no.2
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    • pp.41-50
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    • 2010
  • In this paper, a multi-band antenna with novel structure for mobile communications is designed and fabricated. The proposed antenna has the Multi-band antenna characteristics by two common-grounded slots with different size and angle. In order to reduce size and to enhance the gain of the antenna, a reflector is consisted of chokes on the three sides. It is optimized by using the CST Microwave Studio commercial software based on the FIA(Finite Integration Algorithm) and PBA(Perfect Boundary Approximation), and then the fabricating and measuring is practiced. As a result of measurement, the reflection coefficient is less than -11 dB(VSWR < 1.8) and the gain of antenna is more than 6dBi at 824~894MHz and 1885-2500MHz.

The 7th earth science curriculum and comparative analysis of contents that is exhibited in the science museum - laying stress on high school earth science I, II (제 7차 지구과학 교육과정과 과학관 전시 내용의 비교 분석 - 고등학교 지구과학 I, II를 중심으로)

  • Lee, Hye-Jung;Lee, Chang-Zin;Shin, Myeong-Kyeong
    • 한국지구과학회:학술대회논문집
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    • 2005.09a
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    • pp.323-330
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    • 2005
  • In this study, searched how science museum reflects personality of course of study and target comparing display contents of science museum with high school earth science Ⅰand Ⅱ of the 7th curriculum. Result of this study is as following. First, area that earth science contents of course of study are exhibited has been less than 50%, and is preponderated by unit. Second, earth science course of study reflection degree of science museum is middle.(2.8 points of perfect score 5 points) Third, number of average mark of contents that is exhibited by science museum in significance level 0.05 lows is difference, and it is no difference by unit.

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Design of Wave Absorber for a Perfectly Conduction Sphere Using the Eigenfunction Series Solution form a Coated Sphere (코팅된 구의 고유함수 해를 이용한 완전도체구의 전파흡수체의 설계)

  • 심재은;전중창;김효태
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.36D no.4
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    • pp.18-24
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    • 1999
  • The design method of a wave absorber for a perfectly conducting sphere is presented. The backscattered field from a coated sphere can be represented as the sum of the reflected field and the creeping wave. The wave absorber for a curved surface has been designed from that the reflection coefficient of the reflected field is zero. For the design of wave absorber for a small sized conducting sphere, the creeping wave should be considered as well as the reflected field. The perfect absorbing conditions are numerically searched using the Newton-Raphson method from the backscattered field of the eigenfunction series solution from a coated sphere. The wave absorber designed by this method exhibits a superior performance of absorption to that designed from the plate type absorbing condition.

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Application of the New Calibration Algorithm of a Straight-Type Five-Hole Pressure Probe (직선형 5공 압력프로브의 새로운 교정 알고리듬 적용)

  • Kim, Jang-Kweon;Oh, Seok-Hyung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.11
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    • pp.863-869
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    • 2008
  • This paper investigated the new calibration algorithm of a straight-type five-hole pressure probe for measuring three-dimensional flow velocity components. This new calibration algorithm was used for velocity data reduction from the calibration map and based on the combination of a look-up, a binary search algorithm and a geometry transformation including the translation and reflection of nodes in a calibration map. The calibration map was expanded up to the application angle, ${\pm}55^{\circ}$ of a probe. This velocity data reduction method showed a perfect performance without any kind of interpolating errors in calculating yaw and pitch angles from the calibration map. Moreover, when it was applied to an actual flow field including a swirling flow, a good result came out on the whole.