• Analytical Science and Technology
• /
• v.22 no.1
• /
• pp.109-117
• /
• 2009

The following concentrations of some PAHs were investigated; [benzo(a)anthracene, chrysene, benzo (b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g, h, i)perylene, indeno (1,2,3-c,d)pyrene] in fish(n=168) and shellfish(n=40). The methodology involved saponification and extraction with n-hexane, clean-up on Sep-Pak Florisil Cartridges and determination by HPLC/FLD (High Performance Liquid Chromatograph/Fluorescence Detector). Overall method recoveries for 8 PAHs spiked into these products ranged from 88 to 112%. The mean level of benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k) fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene and indeno(1,2,3-c,d)pyrene in cooked fish was ND, ND, 0.0009, ND, 0.01, ND, ND, ND and in cooked shellfish was 1.84, 3.51, 0.81, 0.38, 0.39, 0.04, 0.20, ND, respectively.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.3 s.357
• /
• pp.20-25
• /
• 2007

The periodic domain-inversion in the selective areas of $Ti:LiNbO_3$ Mach-Zender waveguides was performed and band-pass modulators and single sideband (SSB) modulators were fabricated by using domain-reversal. The domain wall velocity was precisely controlled by real-time analysis of a poling-induced response current under an applied voltage. The domain wall velocity was significantly affected by the crystal orientation of the domain wall propagation which influenced the final domain geometry. In a certain case, the decomposition of $LiNbO_3$ crystal was observed, for example, under the condition of too fast domain wall propagation. The fabricated band-pass modulator with a periodic domain-inversion structure showed the maximum modulation efficiency at 30.3 GHz with 5.1 GHz 3dB-bandwidth, and SSB modulator was measured to show 33 dB USB suppression over LSB at 5.8 GHz RF.

• Horticultural Science & Technology
• /
• v.18 no.2
• /
• pp.103-106
• /
• 2000

The genetic relationship of Bletilla striata native to Korea and Japan was investigated using random amplified polymorphic DNA (RAPD). The 156 reproducible DNA bands, consisted of 58 polymorphic and 98 monomorphic bands, were obtained by polymerase chain reaction (PCR) with selected 10 random primers. The 8 Bletilla lines have been classified into three groups according to the similarity coefficient obtained by RAPD analysis. The dendrogram showed overall correlationship between similarity coefficient of 0.48 and 0.84. The first group included A (Bletilla striata native to Korea), B (Bletilla striata variegated and native to Korea in Mokpo), C (Bletilla striata variegated and native to Korea), D and E (Bletilla striata native to Japan). In this group, it was showed that B and C had the most similar genetic relationship. The similarity coefficient between D and E was 0.77. D and E had a very close resemblance in plant height and flower color with A native to Korea, respectively. The second group included only G (dwarf Bletilla native to Japan) and had a different morphological character compared to other cultivars. The last group included F and H (dwarf and variegated Bletilla native to Japan) and they had a similarity of variegation.

• Proceedings of the KIEE Conference
• /
• 2001.07b
• /
• pp.596-598
• /
• 2001

This paper presents an analysis of the characteristics in switched reluctance motor (SRM). 2D finite element method (FEM) considering the iron saturation and the actual switching circuit of the SRM drive is applied for the dynamic analysis. The influence of the rotor shape on the radial force and torque ripple is investigated and the optimal shape of rotor pole is proposed to enhance the torque. The radial force characteristics acting on the surface of teeth is investigated by using the Maxwell's magnetic stress tensor method.

• 유체기계공업학회:학술대회논문집
• /
• 2001.11a
• /
• pp.303-308
• /
• 2001

A rotating blade of steam turbines is designed using blade design system. To minimize the design time. quasi three dimensional flow analysis code is adopted to calculate blade section. The blade section lies on a streamline determined by previous steam turbine design procedures. The blade design system makes a transform of streamline coordinates, (m, r$\theta$), to (m', $\theta$) coordinates and all design procedure except 3 dimensional stack-up is performed in the coordinates. Each designed blade section is stacked-up and whole 3 dimensional blade can be modified by correcting 2D section, repeatly. The full 3D numerial analysis for the one stage including designed rotating blade will be performed later

• Mass Spectrometry Letters
• /
• v.13 no.4
• /
• pp.177-183
• /
• 2022

The monomer and dimer structures of the amyloid fragment Aβ(1-16) sequence formed in H₂O were investigated using electrospray ionization mass spectrometry (MS) and tandem MS (MS/MS). Aβ16 monomers and dimers were indicated by signals representing multiple proton adduct forms, [monomer+zH]ⁿ⁺ (=M^z+, z = charge state) and [dimer+zH]^z+ (=D^z+), in the MS spectrum. Fragment ions of monomers and dimers were observed using collision-induced dissociation MS/MS. Peptide bond dissociation was mostly observed in the D1-D7 and V11-K16 regions of the MS/MS spectra for the monomer (or dimer), regardless of the monomer (or dimer) charge state. Both covalent and non-covalent bond dissociation processes were indicated by the MS/MS results for the dimers. During the non-covalent bond dissociation process, the D³⁺ dimer complex was separated into two components: the M¹⁺ and M²⁺ subunits. During the covalent bond dissociation of the D³⁺ dimer complex, the b and y fragment ions attached to the monomer, (M+b_10-15)^z+ and (M+y_9-15)^z+, were thought to originate from the dissociation of the M²⁺ monomer component of the (M¹⁺+M²⁺) complex. Two different D³⁺ complex geometries exist; two distinguished interaction geometries resulting from interactions between the M¹⁺ monomer and two different regions of M²⁺ (the N-terminus and C-terminus) are proposed. Intricate fragmentation patterns were observed in the MS/MS spectrum of the D⁵⁺ complex. The complicated nature of the MS/MS spectrum is attributable to the coexistence of two D⁵⁺ configurations, (M¹⁺+M⁴⁺) and (M²⁺M³⁺), in the Aβ16 solution.

• Journal of Korean Society of Steel Construction
• /
• v.20 no.6
• /
• pp.751-759
• /
• 2008

In this study, the effect of an unsteady flow field around a body of aerostatic/aerodynamic forces were investigated using rectangular cylinders (B/D = 2, 3, 4, 5). Proper orthogonal decomposition (POD) was introduced to the analysis of the fluctuating pressure field that was measured on the stationary/oscillatory B/D=4 rectangular cylinder, and the characteristics of the proper functions with flow patterns were identified. In addition, the physical decoupling and interactions in the different co-existing flow patterns were investigated through POD. The comparison with the identified proper function associated with a particular flow pattern revealed that the Karman vortex is almost not affected by the separation bubble, but that the Karman vortex considerably interferes in the development of the separation bubble around the trailing edge. It can be considered that the Karman vortex induces the increment of the curvature of the substantial separated flow.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.14 no.3
• /
• pp.299-308
• /
• 2001

This paper presents the three-dimensional (3-D) study of the natural vibration of cantilevered laminated composite plates. The Ritz method is used to obtain stationary values of the associated Lagrangian functional with displacements approximated by mathematically complete polynomials satisfying the boundary conditions at the clamped edge exactly. The accuracy of the 3-D model is established through a convergence study of non-dimensional frequencies followed by a comparison of the converged 3-D solutions with analytical and experimental findings in the existing literature. A wide scope of 3-D frequency results explain the influence of a number of geometrical and material parameters for cantilevered laminated plates, namely aspect ratio (a/b), width-to-thickness ratio (a/h), orthotropy of material, number of plies (NP), fiber orientation angle(θ), and stacking sequence.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.29 no.4 s.235
• /
• pp.460-468
• /
• 2005

Analyses of flow and heat transfer characteristics and shape optimization of internally finned circular tubes have been performed for three-dimensional periodically fully developed turbulent flow and heat transfer. CFD and mathematical optimization are coupled in order to optimize the shape of heat exchanger. The design variables such as fin widths $(d_{1},\;d_{2})$ and fin height (h) are numerically optimized by minimizing the pressure loss and maximizing the heat transfer rate for limiting conditions of $d_{1}=0.2\~1.5\;mm,\;d_{2}=0.2\~1.5\;mm,$ and $h=0.2\~1.5mm$. Due to the periodic boundary conditions along main flow direction, the three layers of meshes are considered. The flow and thermal fields are predicted using the finite volume method and the optimization is carried out by means of the sequential quadratic programming (SQP) method which is widely used in the constrained nonlinear optimization problem.

• Applied Biological Chemistry
• /
• v.51 no.3
• /
• pp.171-176
• /
• 2008

The comparative molecular similarity indices analysis (CoMSIA) models between 3${\beta}$-Hydroxy-12-oleanen-28-oic acid (1-30) analogues as substrate molecule and their inhibitory activities ($pI_{50}$) against protein tyrosine phosphatase (PTP)-1B were derived and discussed quantitatively. Listing in order, the CoMFA>CoMSIA${\geq}$HQSAR>2D-QSAR model, these QSAR models had the better statistical values. The optimized CoMSIA F1 model at grid 3.0${\AA}$ had the best predictability and fitness ($q^2$=0.754 and $r^2$=0.976) by field fit alignment. The order of contribution ratio (%) of CoMSIA fields concerning the inhibitory activities was a H-bond acceptor (48.9%), steric field (25.8%) and hydrophobic field (25.4%), respectively. Therefore, the inhibitory activities of substrate molecules against PTP-1B were dependent upon H-bond acceptor field (A) of $R_4$-group. From the analytical results of CoMSIA contour maps, oleanolic acid derivatives will have better inhibition activities if $R_1$ group has H-bond acceptor disfavor, $R_3$group has steric disfavor and $R_4$ group has steric, hydrophobic, H-bond favor.