• Korean Journal of Crystallography
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• v.15 no.2
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• pp.74-77
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• 2004

The crystal structure of Dinitroethylenediaminepalladium(II), $Pd(C_2H_8N_2)(NO_2)_2$, has been determined by X-ray crystallography. Crystal data: a=7.425(3), b=8.480(4), c=11.885(2) ${\AA}$, Orthorhombic, $A2_1ma$ (Space Group No=36), Z=4, V=748.3(4) ${\AA}^3,\;D_c=2.295 gcm^{-3},\;{\mu}=2.457mm^{-1}$. The structure was solved by Patterson method and refined by full matrix least-square methods using unit weights. The final R and S values were $R_1=0.0306,\;R_w=0.0802,\;R_{all}=0.0320,\;and\;S=1.166)$ for the observed 377 reflections. Bond lengths and angles of palladium complex are similar to the previously reported data. The complex structure is one dimensional Reiset's salt type analogue showing zigzag chain of Pd-Pd length and angle of 3.762(2) ${\AA}$ and $161.41(5)^{\circ}$. The complex molecules are linked through inter-and intramolecular hydrogen bonds of 3.05(1) and 3.15(1) ${\AA}$ between oxygen and nitrogen.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.3
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• pp.431-437
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• 2000

Traumatic intrusive luxation, an occurrence common in the primary dentition but one that occurs rarely in the permanent dentition, has a poor prognosis. There have been many treatment approaches such as allowing the tooth to reerupt spontaneously, surgical repositioning and immediate luxation, surgical luxation, and orthodontic repositioning; but all have their own drawbacks. Meanwhile, Turley et al. (1987) have proposed surgical and orthodontic combination therapy to treat intrusion. Surgical and orthodontic combination therapy means to apply the orthodontic traction force immediately after surgical luxation. If ankylosis occurs, orthodontic force may be applied after re-luxation repeatedly. But in cases of complete intrusive luxation, it would be not feasible to bond an orthodontic button or bracket on the tooth directly. Thus, in this case, traction of the tooth was attempted after surgically repositioning it close to the probable original socket site to promote better healing.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4161-4164
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• 2012

Density functional MO calculations for the methylsilole anion of $[C_4H_4SiMe]^-$ and methylgermole anion of $[C_4H_4SiMe]^-$ at the B3LYP (full)/6-311+$G^*$ level (GAUSSIAN 94) were carried out and characterized by frequency analysis. The ground state structure for the methylsilole anion and methylgermole anion is that the methyl group is pyramidalized with highly localized structure. The difference between the calculated $C_{\alpha}-C_{\beta}$ and $C_{\beta}-C_{\beta}$ distances are 9.4 and 11.5 pm, respectively. The E-Me vector forms an angle of $67.9^{\circ}$ and $78.2^{\circ}$ with the $C_4E$ plane, respectively. The optimized structures of the saddle point state for the methylsilole anion and methylgermole anion have been also found as a planar with highly delocalized structure. The optimized $C_{\alpha}-C_{\beta}$ and $C_{\beta}-C_{\beta}$ distances are nearly equal for both cases. The methyl group is located in the plane of $C_4E$ ring and the angle between the E-Me vector and the $C_4E$ plane for the methylsilole anion and methylgermole anion is $2.0^{\circ}$ and $2.3^{\circ}$, respectively. The energy difference between the ground state structure and the transition state structure is only 5.1 kcal $mol^{-1}$ for the methylsilole anion. However, the energy difference of the methylgermole anion is 14.9 kcal $mol^{-1}$, which is much higher than that for the corresponding methylsilole monoanion by 9.8 kcal $mol^{-1}$. Based on MO calculations, we suggest that the head-to-tail dimer compound, 4, result from [2+2] cycloaddition of silicon-carbon double bond character in the highly delocalized transition state of 1. However, the inversion barrier for the methylgermole anion is too high to dimerize.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3771-3776
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• 2010

The dynamics of the $CN^-$-ligated ferric cytochrome c (CytcCN) in $D_2O$ at 283 K following Q-band photoexcitation at 575 nm was observed using femtosecond time-resolved vibrational spectroscopy. The equilibrium vibrational spectrum of the CN stretching mode of CytcCN shows two overlapping bands: one main band (82%) at $2122\;cm^{-1}$ with $23\;cm^{-1}$ full width at half maximum (fwhm) and the other band (18%) at $2116\;cm^{-1}$ with $7\;cm^{-1}$ fwhm. The time-resolved spectra show bleaching of the CN fundamental mode of CytcCN and two absorption features at lower energies. The bleach signal and both absorption features are all formed within the time resolution of the experiment (< 200 fs) and decay with a life time of 1.9 ps. One transient absorption feature, appearing immediately red to the bleach signal, results from the thermal excitation of low-frequency modes of the heme that anharmonically couple to the CN fundamental mode, thereby shifting the CN mode to lower energies. The shift of the CN mode decays with a lifetime of 2 ps, equivalent to the time scale for vibrational cooling of the low-frequency heme modes. The other transient absorption feature, which is 3.3 times weaker than the bleach signal and shifted $27\;cm^{-1}$ toward lower energies, is attributed to the CN mode in an electronically excited state where the CN bond is weakened with a lowered extinction coefficient. These observations suggest that photoexcited CytcCN mainly undergoes ultrafast radiationless relaxation, causing photo-deligation of $CN^-$ from CytcCN highly inefficient. As also observed in $CN^-$-ligated myoglobin, inefficient ligand photodissociation might be a general property of $CN^-$-ligated ferric hemes.

• Korean Journal of Crystallography
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• v.6 no.2
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• pp.103-110
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• 1995

The crystal structure of 1-Cyclopropyl-7-(2,7-diazabicyclo[3.3.0]oct-4-en-7-yl)-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (HCI salt) has been determined from single crystal x-ray diffraction study ; C20H21N3O4FCl, Monoclinic, C2/c, a=28.349(2)Å, b=11.941(2)Å, c=12.806(2)Å, β=96.428(9)°, V=4307.8Å3, T=296(2)K, Z=8, CuKα(λ=1.5418Å). The molecular structure was solved by direct method and refined by full-matrix least squares to a final R=4.96% for 2258 unique observed F0>4σ(F0) reflections and 293 parameters. The conformation of the molecule is stabilized by an intramolecular O(28)-H(28)…O(25) [2.517(4)Å, 156.7(447)°] hydrogen bond. Intermoleculars distances correspond to van der Waals contacts.

• Journal of the Korean Chemical Society
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• v.34 no.1
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• pp.29-36
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• 1990

Cholesteryl pentyl carbonate $(C_{33}H_{56}O_3)$ is monoclinic, space group P21, with a = 12.484(3), b = 9.043(3), c = 14.053(3)$\AA$, ${\beta} = 94.12(2)^{\circ}$ and z = 2. The intensity data were measured for the 2969 reflections within sin $\theta/\lambda = 0.52 {\AA}^{-1}$, using an automatic four--circle diffractometer and graphite monochromated Mo-K$\alpha$ radiation. The atomic coordinates from cholesteryl octanoate were used in an initial trial structure and the structure was refined by full-matrix least squares methods. The final R-factor was 0.12 for 1164 observed reflections. The pentyl group has shortened bond lengths due to the high thermal vibrations in this region. Adjacent molecules are related by $2_1$ screw axis so that they are arranged in an antiparallel array, corresponding to the Monolayer Type II packing mode. There are close packings of cholesteryl groups within the monolayers. This packing type is similar to those of cholesteryl hexanoate, octanoate, hexyl carbonate and oleate.

• Bulletin of the Korean Chemical Society
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• v.18 no.1
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• pp.14-18
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• 1997

Sulconazole nitrate, C18H16Cl3N3O3S, crystallizes in monoclinic, space group C2/c, with a=14.401(1), b=8.051(1), c=34.861(2) Å, β=95.9(1)°, g=0.58 mm-1, Dc=1.523 g/cm3, Dm=1.522 g/cm3, F(000)=1888.0, and z=8. Intensities for 2460 unique reflections were measured on a CAD4 diffractometer with graphited-monochromated Mo-Kα radiation. The structure was solved by direct method and refined by full matrix least squares to a final R=0.071 for 2182 reflections (Io > 2σIo). The bond lengths and angles are comparable with the values found in the analogues imidazole derivatives. The 2,4-dichlorophenyl ring(A) and the p-chlorophenyl ring(B) are almost planar with different heights [dihedral angle 17.3°] while the imidazole ring(C) is nearly perpendicular to the two phenyl rings[dihedral angles about the two rings A, B are 110.8° and 96.1° respectively]. In order to understand the overall conformation we calculated the selected distances (l1, l2, l3) among the center of the three rings and considered the imaginary plan D[C(7), C(9) and C(16)]. The two polar group S(8) and N(19) do not have gauche conformation and l2 value (4.47 Å) is shorter than the other imidazole derivatives. One -NO3 group are hydrogen bonded the two neighbored sulconazole molecules. The molecular crystal packing is also formed by two hydrogen bondings and van der Waals forces.

• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.823-826
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• 1995

The crystal structure of a sulfur sorption complex of the dehydrated partially Co2+ exchanged zeolite A (a=12.058(2) Å) has been determined by single-crystal X-ray techniques. The crystal structure was solved and refined in cubic space group Pm3m at 21(1) ℃. Ion Exchange with aqueous 0.05 M Co(NO3)2 was done by the static method. The crystal of Na4Co4-A was dehydrated at 380 ℃ and 2 × 10-6 Torr for 2 days, followed by exposure to about 100 Torr of sulfur at 330 ℃ for 72 h. Full matrix least-squares refinement converged to R1=0.084 and Rw=0.074 with 102 reflections for which I > 3σ(I). Crystallographic analysis shows that 2.8 Co2+ ions and 4 Na+ ions per unit cell occupy 6-ring sites on the threefold axes. 1.2 Co2+ ions occupy the 8-ring sites on fourfold axes. 2.8 Co2+ ions at Co(1) are recessed 0.66 Å into the large cavity and 4 Na+ ion at Na(1) are recessed 0.77 Å into the sodalite cavity from the (111) plane of O(3)'s. Approximately 16 sulfur atoms were sorbed per unit cell. Two S8 rings, each in a butterfly form, are found in the large cavity. The bond length between S and its adjacent S is 2.27(3) Å. The distance between 6-ring Co2+ ion and its adjacent sulfur is 2.53 (2) Å and that between 8-ring Co2+ ions and its adjacent sulfur is 2.72(9) Å. The angles of S-S'-S and S'-S-S'/ in octasulfur rings are 119.0(2)°and 113.0(2)°, respectively.

• Structural Engineering and Mechanics
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• v.78 no.3
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• pp.231-253
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• 2021

Pure bending loading conditions are not frequently occurred in practical engineering, but the flexural researches are important since it's the basis of mechanical property researches under complex loading. Hence, the objective of this paper is to investigate the flexural behavior of concrete-filled rectangular steel tube (CFRT) through combined experimental and numerical studies. Flexural tests were conducted to investigate the mechanical performance of CFRT under bending. The load vs. deflection curves during the loading process was analyzed in detail. All the specimens behaved in a very ductile manner. Besides, based on the experimental result, the composite action between the steel tube and core concrete was studies and examined. Furthermore, the feasibility and accuracy of the numerical method was verified by comparing the computed results with experimental observations. The full curves analysis on the moment vs. curvature curves was further conducted, where the development of the stress and strain redistribution in the steel tube and core concrete was clarified comprehensively. It should be noted that there existed bond slip between the core concrete and steel tube during the loading process. And then, an extensive parametric study, including the steel strength, concrete strength, steel ratio and aspect ratio, was performed. Finally, design formula to calculate the ultimate moment and flexural stiffness of CFRTs were presented. The predicted results showed satisfactory agreement with the experimental and FE results. Additionally, the difference between the experimental/FE and predicted results using the related design codes were illustrated.

• Computers and Concrete
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• v.24 no.2
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• pp.159-172
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• 2019

This paper presents an investigation into the flexural behavior of reinforced concrete (RC) beams retrofitted by ultra-high performance fiber-reinforced concrete (UHPFRC) layers. The experimental study has been conducted in two parts. In the first part, four methods of retrofitting with UHPFRC layers in both the up and down sides of the beams have been proposed and their efficiency in the bonding of the normal concrete and ultra-high performance fiber-reinforced concrete has been discussed. The results showed that using the grooving method and the pre-casted UHPFRC layers in comparison with the sandblasting method and the cast-in-place UHPFRC layers leads to increase the load carrying capacity and the energy absorption capacity and causes high bond strength between two concretes. In the second part of the experimental study, the tests have been conducted on the beams with single UHPFRC layer in the down side and in the up side, using the effective retrofitting method chosen from the first part. The results are compared with those of non-retrofitted beam and the results of the first part of experimental study. The results showed that the retrofitted beam with two UHPFRC layers in the up and down sides has the highest energy absorption and load carrying capacity. A finite element analysis was applied to prediction the flexural behavior of the composite beams. A good agreement was achieved between the finite element and experimental results. Finally, a parametric study was carried out on full-scale retrofitted beams. The results indicated that in all retrofitted beams with UHPFRC in single and two sides, increasing of the UHPFRC layer thickness causes the load carrying capacity to be increased. Also, increases of the normal concrete compressive strength improved the cracking load of the beams.