• Journal of the Korean Chemical Society
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• v.57 no.3
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• pp.329-334
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• 2013

A pine needle-embedded graphite enzyme electrode, of which bonding agent is CSM rubber, was newly designed and its electrochemistry was studied based on the amperometry. It involved a ground green leaves of pine tree as a zymogen together with electrochemical mediator, ferrocene within the paste. The plots of ln($i(1-e^{nf{\eta}})$) vs. ${\eta}$ and Lineweaver-Burk at the low potential (-100 to -500 mV) showed good linearities indicating that the amperometric response is by the catalytic power of pine peroxidase. Electrochemical parameters obtained, symmetry factor (${\alpha}$, 0.17), limiting current ($i_1$, 1.99 $A/cm^2$), exchange current density ($i_0$, $5.86{\times}10^{-5}\;A/cm^2$), Michaelis constant ($K_M$, $1.68{\times}10^{-3}$ M) and many others showed that pine peroxidase discharges the role of catalyst quantitatively on the electrode surface. Those proved that the practical use of pine peroxidase is promising in place of the marketed.

• Journal of Periodontal and Implant Science
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• v.39 no.1
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• pp.27-36
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• 2009

Purpose: The stability of periodontal condition and marginal bone level were important to achieve long-term success of dental implant treatment. The aim of this study was to evaluate periodontal conditions and marginal bone loss around 67 GSII(OSSTEM, Seoul, Korea) dental implants with dual-microthread at the neck portion, 1 year after prosthetic loading. Materials and methods: Sixty-seven GS II dental implants in 27 patients(mean age; $47.4{\pm}14.0$ years) who received implant treatments at Pusan National University Hospital, were included in this study. Thirteen US II(OSSTEM, Seoul, Korea) implants with smooth neck design were selected for the control group. Periodontal and radiographic evaluations were carried out at baseline, 6 months and 12 months after prosthetic loading. Results: In the GS II group, plaque index(PI), gingival index(GI) and probing depth(PD) increased as time passed. In the US II group, GI and PD increased. Although marginal bone level was lower in the US II group in all evaluation periods, the changes between the periods were not statistically significant(p>0.05). In each period, periodontal parameters were not statistically significant between groups. Conclusion: One year after prosthetic loading, GS II and US II dental implants showed similar periodontal conditions and marginal bone response, and were within the criteria of success.

• Computers and Concrete
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• v.15 no.4
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• pp.687-707
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• 2015

A finite element computer code for short-term analysis of steel-concrete composite structures is extended to study long-term effects under service loads, in the present work. Long-term effects are important in engineering design because they influence stress and strain distribution of the structural system and therefore contribute to the increment of deflections in these structures. For creep analysis, a rheological model based on a Kelvin chain, with elements placed in series, was employed. The parameters of the Kelvin chain were obtained using Dirichlet series. Creep and shrinkage models, proposed by the CEB FIP 90, were used. The shear-lag phenomenon that takes place at the concrete slab is usually neglected or not properly taken into account in the formulation of beam-column finite elements. Therefore, in this work, a three-dimensional numerical model based on the assemblage of shell finite elements for representing the steel beam and the concrete slab is used. Stud shear connectors are represented for special beam-column elements to simulate the partial interaction at the slab-beam interface. The two-dimensional representation of the concrete slab permits to capture the non-uniform shear stress distribution in the horizontal plane of the slab due to shear-lag phenomenon. The model is validated with experimental results of two full-scale continuous composite beams previously studied by other authors. Results are given in terms of displacements, bending moments and cracking patterns in order to shown the influence of long-term effects in the structural response and also the potentiality of the present numerical code.

• Animal cells and systems
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• v.16 no.4
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• pp.329-336
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• 2012

This study evaluated ecological health, using various biomarkers and bioindicators, of pale chub (Zacco platypus) as a sentinel species, in Daejeon Stream, South Korea, during AprilMay 2011. The biomarkers and bioindicators were compared among three sites of control: Reference ($C_z$), transition ($T_z$), and the urban zones ($U_z$); and the 7-Ethoxyresorufin-O-deethylase (EROD) activity, DNA damage, acetylcholinesterase (AChE) activity, and vitellogenin (VTG) concentrations were more significantly increased in the $U_z$ than in the $C_z$. Also, physiological markers such as condition factor, liver somatic index, visceral somatic index, and gonad somatic index were significantly increased in the $U_z$ than in the $C_z$. For the health assessments, three categorized parameters of blood chemistry, molecular biomarkers, and physiological bioindicators were standardized and calculated as a star-plot, representing values of Integrated Health Response (IHR). Values of IHR had more significant (P<0.05) increases in the $U_z$ than any other zones, indicating an impairment of ecological health by organic matter, nutrients (N, P), and toxic chemicals. This study is based on low levels of biological organization approach of molecular and physiological biomarkers and bioindicators, so further study of high-levels of biological organization approach such as community and population is required for overall range of health assessments. The approach of IHR values, however, may be useful in providing early warning of future impacts on ecological health.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.6
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• pp.84-92
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• 2005

This paper is concerned with optimum design of a center-pillar assembly induced by the high-speed side impact of the vehicle. In order to simulate deformation behavior of the center-pillar assembly, simplified finite element model of the center-pillar and a moving deformable barrier are developed based on results of the crash analysis of a full vehicle model. In optimization of the deformation shape of the center-pillar, S-shaped deformation is targeted to guarantee reduction of the injury level of a driver dummy in the crash test. Tailor-welded blanks are adopted in the simplified center-pillar model to control the deformation shape of the center-pillar assembly. The thickness of each part which constitutes the simplified model is selected as a design parameter. The thickness of parts which have significant effect on the deformation mechanism are selected as design parameters with sensitivity analysis based on the design of experiment technique. The objective function is constructed so as to minimize the weight and lead to an S-mode deformation shape. The result shows that the simplified model can be utilized effectively for optimum design of the center-pillar members with remarkable saving of computing time.

• Korean Journal of Materials Research
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• v.11 no.6
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• pp.492-497
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• 2001

We report the characteristics and the dependence of sputter-deposited Ta films on the process parameters. The properties of as-deposited Ta films such as deposition rate, resistivity, Rs uniformity, reflectivity, and stress were investigated and analyzed as a function of process parameter using a statistical experimental method. The functional relationships between the independent and dependent variables were predicted by surface response. The optimal deposition condition of DC magnetron sputtered Ta films was obtained at the chamber pressure of 2 mTorr, power density of 8 W/$\textrm{cm}^2$, and substrate temperature of 2$0^{\circ}C$ by means of resistivity and Rs uniformity. The fitness value for quadratic model as evaluated by the R- square was 0.85~ 0.9 without pooling. The as-deposited Ta films exhibited the resistivity of ~180$\mu$$\Omega$cm with Rs uniformity of ~2%. The transmission electron microscopy and x-ray diffractometry identified that the phase of as-deposited film was $\beta$-Ta having the grain size of 100~200.

• Tuberculosis and Respiratory Diseases
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• v.77 no.1
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• pp.13-17
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• 2014

Background: This study analyzed the negative prognostic factors in patients who received second-line chemotherapy for advanced inoperable non-small cell lung cancer (NSCLC). Methods: We retrospectively reviewed the records of 137 patients with inoperable stage III-IV NSCLC who received second-line chemotherapy. The effects of clinical parameters on survival were analyzed and the hazard ratios (HR) for mortality were identified by a Cox regression analysis. Results: Sex, age older than 65 years, smoking history, cell type, T-stage, best response to first-line chemotherapy and first-line chemotherapy regimen were significant negative predictors in univariate analysis. The multivariate analysis showed that patients older than 65 years (HR, 1.530; 95% confidence interval [CI], 1.020-2.297), advanced T stage (T4 vs. T1; HR, 2.273; 95% CI, 1.010-5.114) and non-responders who showed progression with first-line chemotherapy (HR, 1.530; 95% CI, 1.063-2.203) had higher HR for death. Conclusion: The age factor, T stage and responsiveness to first-line chemotherapy were important factors in predicting the outcome of patients with advanced NSCLC who received second-line chemotherapy. The results may help to predict outcomes for these patients in the future.

• Journal of Environmental Science International
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• v.23 no.4
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• pp.661-672
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• 2014

Due to tidal force, it is very difficult to estimate the hydraulic parameters of high permeable aquifer near coastal area in Jeju Island. Therefore, to eliminate the impact of tidal force from groundwater level and estimate the hydraulic properties, tidal response technique has been mainly studied. In this study we have extracted 38 tidal constituents from groundwater level and harmonic constants including frequency, amplitude, and phase of each constituent using T_TIDE subroutine which is used to estimate oceanic tidal constituents, and then we have estimated hydraulic diffusivity associated with amplitude attenuation factor(that is the ratio of groundwater level amplitude to sea level amplitude for each tidal constituent) and phase lag(that is phase difference between groundwater level and sea level for each constituent). Also using harmonic constants for each constituent, we made the sinusoidal wave and then we constructed the synthesized wave which linearly combined sinusoidal wave. Finally, we could get residuals(net groundwater level) which was excluded most of tidal influences by eliminating synthesized wave from raw groundwater level. As a result of comparing statistics for synthesized level and net groundwater level, we found that the statistics for net groundwater level was more insignificant than those of synthesized wave. Moreover, in case of coastal aquifer which the impact of tidal force is even more than those of other environmental factors such as rainfall and groundwater yield, it is possible to predict groundwater level using synthesized wave and regression analysis of residuals.

• Transactions on Electrical and Electronic Materials
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• v.4 no.6
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• pp.17-20
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• 2003

This paper describes the effect of halogenic gettering during oxide passivation of commercial solar cell with the $N^{+}$-P-$N^{+}$ structure. In order to study the effect of halogenic gettering on $N^{+}$-P-$N^{+}$ structure mono-crystalline silicon solar cell, we performed conventional POCl$_3$ diffusion for emitter formation and oxide passivation in the presence of HCl vapors. The $N^{+}$-P-$N^{+}$ structure based silicon solar cells were found to have higher short circuit current and minority carrier lifetime. Their performance was also found to be superior than the conventional $N^{+}$-P-$N^{+}$ structure based mono-crystalline silicon solar cell. The cell parameters of the $n^{+}$-p-$p^{+}$ and $n^{+}$-p-$n^{+}$ structure based cells, passivated by HCl assisted oxidation were measured. The improvement in $I_{sc}$ was attributed to the effect of the increased diffusion length of minority carriers, which came from the halogenic gettering effect during the growth of passivating oxide. The presence of chlorine caused gettering of the cells by removing the heavy metals, if any. The other advantage of the presence of chlorine was the removal of the diffusion induced (in oxygen environment) stacking faults and line defects from the surfaces of the silicon wafers. All these effects caused the improvement of the minority carrier lifetime, which in-turn helped to improve the quality of the solar cells.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.3
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• pp.245-252
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• 2010

This paper proposes an improved filter synthesis method for dual-band filters based on coupled lines loaded with shunt stubs. The conventional design method relies on equality of the response of the conventional single-band filter and its dual-band counterpart at two frequencies. On the other hand, the proposed method is based on equivalence of the propagation constants and the image impedances of the two filters. Therefore, the proposed method does not suffer from bandwidth reduction phenomena, which requires complex compensating process in the conventional method. Also, the alternative design parameters provided by the demonstrated method enable to construct dual-band filters with more flexibility. For experimental verification, a Chebyshev type dual-band filter with center frequencies at 1 GHz and 3.5 GHz is designed and fabricated. The measured results are in excellent agreement with the full-wave simulated results.