• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.1975-1988
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• 2024

It is important to maintain cladding integrity in spent nuclear fuel management. This study proposes a numerical analysis method to evaluate the fracture resistance of irradiated zirconium alloy cladding under pinch load known to cause Mode-III failure. The mechanical behavior and fracture of the cladding under pinch loading can be evaluated by a Ring Compression Test (RCT). To simulate the fracture of hydride precipitates, zirconium matrix, and Zr/hydride interfaces under the stress field generated by RCT, a micro-structure crack propagation simulation method based on Continuum Damage Mechanics (CDM) has been proposed. Our RCT simulation model was constructed from microscopic images of irradiated cladding. In this study, we developed an automated process to generate a pixel-based finite element model by separating the hydride precipitates, zirconium matrix, and interfaces using an image segmentation method. The appropriate element size was selected to ensure the efficiency and accuracy of a crack propagation simulation. The load-displacement curves and strain energies from RCT were compared and analyzed with the simulation results of different element sizes. The finalized RCT simulation model can be used to establish the failure criterion of fuel rods under pinch loading. The advantages and limitations of the proposed method are fully discussed here.

• Korean Journal of Optics and Photonics
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• v.16 no.4
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• pp.384-391
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• 2005

A polymer optical microring resonator, which is laterally coupled to a straight bus waveguide, has been proposed and demonstrated using a nanoimprint technique. The propagation loss of the ring waveguide and the optical power coupling between the ring and bus waveguides was calculated by using a beam propagation method, then the dependence of the device performance on them was investigated using a transfer matrix method. We have especially introduced an imprint stamp incorporating a smoothing buffer layer made of a silicon nitride thin film. This layer played an efficient role in improving the sidewall roughness of the waveguide pattern engraved on the stamp and thus reducing the scattering loss. As a result the overall Q factor of the resonator was greatly increased. Also it reduced the gap between the ring and bus waveguides effectively to enhance the coupling between them, without relying on the direct writing method based on an e-beam writer. As for the achieved device performance at the wavelength of 1550 nm, the quality factor, the extinction ratio, and the free spectral range were ~103800, ~11 dB, and 1.16 m, respectively.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.316-316
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• 2006

The preparation of an organic/inorganic polymer hybrid from a novolac derivatives is described. The hybrid was prepared by the acid-catalyzed solgel reaction of phenyl-trimethoxysilane (PhTMOS) in the presence of anisole novolac. The resulting film was transparent and showed a high heat stability. The dispersion of two components might be due to the utilization of the p-p interaction between the phenyl ring of the silica matrix and that of novolac. This makes it possible to prepare a hybrid glass having a highly content of novolac derivatives.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.471-474
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• 2002

Three-ring types liquid crystalline compounds having fluoro and isothiocyanate substituent were synthesized and their physical and electro-optical properties were measured to evaluate the applications to active matrix VA liquid crystal displays. The tetrakis(triphenylphosphine)palladium(0) catalyzed cross coupling of aryl boronic acids with aryl halides is used to prepare trans-4'-Alkoxy-2,3-difluoro-3'-isothiocyanato-4-(4-alkylcyclohexyl}-biphenyl series. The synthesized compounds showed the nematic liquid crystalline phase and the negative dielectric anisotropy. The prepared mixtures showed faster response time and lower threshold voltage than their host mixture.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.157-160
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• 1988

This paper describes the development of the Interfacing unit between PSTN and interphone network. The designed and realised system detects the ring signal from PSTN and makes off-hook condition when it is detected. Then the caller can hear the response tone from the unit and the tones of the interphone network condition. The developed system receives the interphone number to which the caller wants to connect by MFC tones and drives Interphone switch matrix. Thus, a call is connected to the interphone user directly. The caller may press the interphone number up to 10 digits and the last two of which are recognized as valid ones. The caller must press the first digit within 20 seconds after system response.

• Archives of Pharmacal Research
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• v.19 no.1
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• pp.71-73
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• 1996

The molecular structure of pirprofen, 3-chloro-4-(2,5-dihydro-1H-pyrrol-1-yl)-.alpha.-methyl-benzeneacetic acid, was determined by single crystal X-ray diffraction analysis. The compound was recrystallized from a mixture of chloroform and toluene in triclinic, space group P over $\bar1,\; with\; a=4.577(1),\; b=11.213(2),\; C=12.485(2){\AA},\alpa.=107.39(1),\;\beta=97.79(1),\;\gamma=92.03(2),\; and Z=2$ The calculated density is $1.384 g/cm^3$. The structure was solved by the direct method and refined by full matrix least-squares procedure to the final R value of 0.034 for 1681 independent reflections. The non-aromatic dihydropyrrol group is found to be coplanar to the central aromatic ring. The molecules are dimerized through the intermolecular hydrogen bonds at the carboxyl group in the crystal.

• Journal of Radiation Protection and Research
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• v.30 no.1
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• pp.31-34
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• 2005

The article is devoted to the study of some hi-and tricyclic derivatives of aziridine as materials lot newindicators of ionizing radiation. To create high sensitive materials some aspects of photo induced ring opening processes in aziridine derivatives in ethanol solutions and in polymeric matrix were studied and two steps character of the processes investigated was established. Two types of radioindicators were suggested and preliminary tested. The new way of synthesis of radiochromic derivatives of aziridine was developed and series of target compounds synthesized.

• Macromolecular Research
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• v.13 no.4
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• pp.321-326
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• 2005

Photochromic diarylethene polymers (DPs) in which 1,2-bis(2-methylbenzo[b ]thiophene-3-yl)hexafluorocyclopentene (BTF6) were covalently grafted onto the polymer main chain as pendant photochromic units were newly synthesized and their photochromic properties were investigated using steady-state and picosecond timeresolved spectroscopies. Polysiloxanes substituted with BTF6 molecules were prepared by sol-gel process using a mixture of tetraethoxysilane (TEOS), a silylated BTF6, and an organically modified silane precursor in the presence of HCl. The polysiloxane film (DP1) prepared from $\omega-methoxy$ poly(ethylene glycol) 3-(triethoxysilyl) propylcarbainate (MPGSC) as the silane precursor showed a much lower glass transition temperature than that (DP2) from heptadecafluorodecyltrimethoxysilane (HDFTMS). The ring-closure quantum yields of DP1 and DP2 were determined to be 0.20 and 0.02, respectively. Such a large difference in the quantum yield was attributed to the polymer matrix environment of the free inner volume.

• Archives of Pharmacal Research
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• v.19 no.2
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• pp.160-162
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• 1996

The structural analysis of tolfenamic acid, 2-[(3-chloro-2-methylphenyl)-amino]benzoic acid, was performed by single crystal X-ray diffraction technique. The compound was recrystallized from a mixture of ether and toluene in triclinic, space group $P2_1/c, \;with\; \partial=3.914(1), \; b=22.\; 020(2), \; c=14.271(1)\;{\AA}, \beta.=94.68(1)^{\circ}, $ and Z=4. The calculated density is $1.418 g/cm^3$. The structure was solved by the direct method and refined by full matrix least-squares procedure to the final R value of 0.039 for 1773 independent reflections. In the molecule, carboxyl group at the anthranilic acid is coplanar to the phenyl ring. The dihedral angle between the two aromatic rings of the molecule is $44.2^{\circ}$ The molecules are dirnerized through the intermolecular hydrogen bonds at the carboxyl group in the crystal.

• Bulletin of the Korean Chemical Society
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• v.6 no.1
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• pp.7-11
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• 1985

The crystal structure of phlorizin, a ${\beta}$ -D-glucopyranoside of a flavonoid dihydrochalcone phloretin, has been determined by single crystal diffraction methods using diffractometer data obtained by the ${\omega}-2{\theta}$ scan technique with Cu $K{\alpha}$ radiation from a crystal with space group symmetry $P2_12_12_1$ and unit cell parameters a = 4.9094 (2), b = 19.109 (1), c = 23.275 (4) $\AA$. The structure was solved by direct methods and refined by full-matrix least-squares to a final R = 0.047 for the 1697 observed reflections. The dihydrochalcone moiety is flat and fully extended. The glucose ring has the $^4C_1$ chair conformation and the conformation of the primary alcohol group is gauche-gauche. The crystal packing is dominated by an extensive hydrogen bonding pattern. There are one strong and two weak intramolecular hydrogen bonds in the phlorizin molecule.