• Title/Summary/Keyword: rod-coil

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Synthesis of an Amphiphilic $\pi$-Conjugated Triblock Copolymer of Poly(9,9-didodecylfluorene-2,7-diyl) and Poly(hydroxyl ethyl methacrylate)

  • Kim, Hyun-Jung;Kim, Hyun-Seok;Kwon, Yong-Ku
    • Macromolecular Research
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    • v.13 no.6
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    • pp.529-532
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    • 2005
  • A novel amphiphilic, symmetric rod-coil, triblock copolymer (denoted as PHEMA-b-PF-b-PHEMA) of poly(9,9-didodecylfluorene-2,7-diyl) (PF) and poly(hydroxyl ethyl methacrylate) (PHEMA) was synthesized. A $\pi$-conjugated poly(9,9-didodecylfluorene-2,7-diyl) (PF) was used as a rodlike midblock segment and connected with hydrophilic end blocks of poly(hydroxyl ethyl methacrylate) (PHEMA) by using an ATRP technique. The chemical structure of PHEMA-b-PF-b-PHEMA was confirmed by $^{1}H$-NMR and GPC, and its PL properties were investigated in selected solvents. Due to the dissimilarities in molecular conformation and solubility between PHEMA and PF blocks, both block segments were segregated to display a phase-separated morphology on a Si wafer.

The Applications of the Duplex Stainless Steel as Hyperthermia Materials

  • Kim, Young-Kon
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2009.05a
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    • pp.7.1-7.1
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    • 2009
  • The use of Duplex stainless steel as a thermo-implant categorizes into two clinical applications: hyperthermia and thermal ablation or destruction. The goal of hyperthermia is to destroy the heat-sensitive abnormal cells and minimize normal cell death maintaining heat between $42^{\circ}C$ and $46^{\circ}C$. Thermal ablation takes place when the local tissue temperature increases greater than $46^{\circ}C$. This elevated temperature denatures protein irreversibly resulting cellular death. The author introduced several thermo-implants such as thermo-rod, thermo-stent, thermo-coil and thermoacupuncture-needle. Those thermo-implants are made of duplex stainless steel which can produce regulated heat by itself within an induction magnetic field. Thermal ablation characteristics of the thermo-rod on tumor hyperthermia depend on configurations of the thermo-rods and the magnitude of the induction magnetic strength. The exothermic properties of the thermo-implants can be characterized using the calorimetric test and the heat affected zone(HAZ) analyses in vitro. Thermal radiation studies using thermo-coils and thermo-stents show the capability of the occlusion of animal blood vessels and inhibiting the proliferation of the abnormal smooth muscle cell growth and inflammatory cell reactions maintaining the heat between $42^{\circ}C$ and $46^{\circ}C$ minimizing a normal cell death in the study on external iliac artery of the New Zealand White (NZW) rabbit. Thermal stimulation study using thermo-acupuncture needles suggests the potential applications of the automated acupunctural therapies.

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Invertible Nanofibers with Tunable Stiffness from Self-Assembly of an Amphiphilic Wedge-Coil Molecule

  • Kim, Jung-Keun;Lee, Eun-Ji;Lee, Myong-Soo
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.249-249
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    • 2006
  • We have prepared an amphiphilic wedge-coil molecule consisting of a hydrophobic wedge-like segment and a hydrophilic poly(ethylene oxide) (PEO) segment. The wedge-coil block molecule self-assembles into cylindrical nanofibers in both polar as well as nonpolar solvents. Remarkably, the resulting nanofibers, as solvent polarity change from water to n-hexane, change from highly flexible coil-like to stiff rod-like characteristics. This dynamic switching in the stiffness of the nanofibers in response to solvent polarity is attributed to the structural inversion of cylindrical core from bulky dendritic segments with amorphous nature to crystallizable linear PEO segments.

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Wobble and Nonconcentricity Effects in Eddy Current Test of Tubes or Rods (튜브, 봉류의 와전류 탐상시 시편 변위에 의한 신호 변화)

  • Kim, Y.J.;Kim, Y.G.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.9 no.2
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    • pp.37-41
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    • 1989
  • The purpose of this paper is to estimate the effect of wobble and nonconcentricity of tubes or rods in eddy current test with encircling test coils. Because the eddy current induced in a sample is related to the total magnetic flux linkages, the information about magnetic field distribution in a coil is important. In theoretical study, magnetic field distribution in a single turn coil was calculated and variation of impedance according to the difference of sample positions was presumed. Magnetic field intensity at inside of a solenoidal coil was measured and compared with the theoretical estimation. In experiment, impedance loci of a coil encircling an aluminum rod were measured at different sample positions. The effect of crack positions was examined at same sample positons.

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A Monitoring Method of Movements in Control Rod Drive Mechanism using Wavelet Transform (웨이블릿 변환을 이용한 원자로 제어봉구동장치 동작 감시 방법)

  • Cheon, Jong-Min;Kim, Choon-Kyoung;Park, Min-Kook;Lee, Jong-Moo;Kwon, Soon-Man
    • Proceedings of the KIEE Conference
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    • 2005.10b
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    • pp.270-272
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    • 2005
  • In this paper, we proposed a new method detecting actions of some components driven by the coil excitation. Nuclear power reactors are typically controlled by the movement of several neutron-absorbing control rods into or out of the reactor core. For moving control rods, we use an electromagnetic-jack-typed mechanism, which is called Control Rod Drive Mechanism. This mechanism moves control rods by the step composed of sequential actions of components. In case any mechanical problems happen in the mechanism, the orders for the control rod movement from the higher system cannot be performed properly. This abnormal state must be monitored and the sequential actions of the components can be the monitoring target. The actions of components generate some deviations in the profiles of the currents flowing into the coils in the mechanism. We focused on this phenomena and devised a new method of detecting the actions of the components in Control Rod Drive Mechanism by using the wavelet transform for observing the current profile.

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Raman and Fluorescence Studies of Thermotropic Liquid-Crystalline Oligomers with Different Type of Coils

  • Chae, Jong-Bok;Yu, Soo-Chang;Lee, Youn-Sik
    • Bulletin of the Korean Chemical Society
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    • v.28 no.2
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    • pp.193-199
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    • 2007
  • Raman and fluorescence spectroscopies were employed to study the coil effects on the intermolecular structure of a rod-coil liquid crystalline (LC) oligomer, the esterification products of ethyl 4-[4'-oxy-4-biphenylcarbonyloxy]- 4'-biphenylcarboxylate with poly(propylene)oxides (PPO) (DP=12) and poly(ethylene oxide)s (PEO) (DP=12). Three different vibrational modes (carbonyl, aromatic C-H, and aromatic C=C) obtained from the Raman experiment at variable temperature indicate that PPO and PEO coils induce the hydrogen bonding in a different manner. Further information about the micro-environment around the mesogenic unit obtained by fluorescence excitation spectra of P12-4 (LC with PPO coil) and 12-4 (LC with PEO coil) suggests that the mesogenic unit of P12-4 is quite different from that of 12-4 in intermolecular structure. This study supports the results obtained only from Raman spectroscopy, providing more accurate information about the intermolecular structural changes of liquid crystalline polymers at a molecular level during the phase transitions.

Developed Compact Injection Molding Machine for Desktop (탁상용 소형 사출 성형기 개발)

  • Lee, Byung-Ho;Shin, Dong-Hwa
    • Journal of the Korean Society of Industry Convergence
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    • v.21 no.5
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    • pp.257-263
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    • 2018
  • It is a small injection molding machine for table top considering the material heating mechanism and the design and structure stability by securing the mechanism that compresses the inside of the material heating tube by using the electric actuator and by providing space between the body and the material heating tube to reduce heat loss Develop body. An electric actuator suitable for applying pressure to the inside of a material heating tube is a mechanical system composed of a rigid structure. Since a large force is repeatedly applied to the electric actuator and the push rod, the interaction between the moving parts and the dynamic Maximum stress through analysis and prediction of fatigue life of critical parts The pushrod reflects the structural analysis results of the electric actuator and the push rod, and pushes the inside of the material heating tube by the push rod to inject the molten material from the nozzle into the mold. The pushrod operates by the operation of the electric actuator. The material heated by the coil heater is ejected through the nozzle by the pressure of the material heating tube, and the material heating tube and the nozzle are also lowered at the same time as the push rod is lowered, so that the material is closely adhered to the mold. We want to study the completion of the injection.

Time dependent numerical simulation of MFL coil sensor for metal damage detection

  • Azad, Ali;Lee, Jong-Jae;Kim, Namgyu
    • Smart Structures and Systems
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    • v.28 no.6
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    • pp.727-735
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    • 2021
  • Recently, non-destructive health monitoring methods such as magnetic flux leakage (MFL) method, have become popular due to their advantages over destructive methods. Currently, numerical study on this field has been limited to simplified studies by only obtaining MFL instead of induced voltage inside coil sensor. In this study, it was proposed to perform a novel numerical simulation of MFL's coil sensor by considering vital parameters including specimen's motion with constant velocity and saturation status of specimen in time domain. A steel-rod specimen with two stepwise cross-sectional changes (i.e., 21% and 16%) was fabricated using low carbon steel. In order to evaluate the results of numerical simulation, an experimental test was also conducted using a magnetic probe, with same size specimen and test parameters, exclusively. According to comparative results of numerical simulation and experimental test, similar signal amplitude and signal pattern were observed. Thus, proposed numerical simulation method can be used as a reliable source to check efficiency of sensor probe when different size specimens with different defects should be inspected.