• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.4 s.107
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• pp.380-386
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• 2006

Electric fuel sender fur the vehicle fuel gauge system was designed and fabricated based on the CPW(Co-Planer Waveguide) transmission line theory. It is applied on this system that characteristic impedance of RF transmission line can be varied by the surrounded material of the line. By the characteristic impedance owing the level of gasoline or diesel fuel in vehicle fuel tank, CPW line has corresponding reflected signal as much as changed impedance. Detected signal is amplified, and delivered to fuel indicator into cluster unit on dash board. Conventional floating mechanical buoy level gauge has several defects as low reliability and high break down rate by mechanical operation, and has not good linearity for the fuel level difference. CPW line with electric circuits are constructed on 1.6 mm thickness epoxy substrate, and measurement shows that this system has more accurate level and better linearity than conventional mechanical system. New electric fuel sender which has good productivity with long lifetime and low-in-cost by the SMT chip assembling could be replaced this system with conventional floating buoy system.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.587-597
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• 2010

Analysis of the behavior of a laterally loaded pile is important in the design of critical civil structures. Recently, the electric strain gauge has been widely used to measure the strains along the pile. The electric strain gauge, due to lack of durability, is inappropriate in the use of long-term measurements. Herein, the feasibility of implementing the FBG sensor was investigated using a cantilever-type calibrator in laboratory. A special calibrating tool called "cantilever-calibrator" was used to calibrate the FBG sensors. The calibrator consists of a special calibration beam, a holding-clamp at one end of the beam, and a micrometer on the other end. Three FBG sensors were installed on the calibration beam. The strains measured by FBG sensors were compared with those calculated theoretically using cantilever beam theory. The calibration factor of FBG sensors were suggested to compensate the difference between measured and calculate strains.

• Computers and Concrete
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• v.20 no.5
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• pp.595-603
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• 2017

Piezoceramic transducers have been widely used in the health monitoring of civil structures. However, in most cases, they are used as sensors either to measure strain or receive stress waves. This paper proposes a method of using piezoelectric transducers as strain gauges and acoustic emission (AE) sensors simultaneously. The signals received by piezoceramic transducers are decomposed into different frequency components for various analysis purposes. The low-frequency signals are used to measure strain, whereas the high-frequency signals are used as acoustic emission signal associated with local damage. The b-value theory is used to process the AE signal in piezoceramic transducers. The proposed method was applied in the bending failure experiments of two reinforced concrete beams to verify its feasibility. The results showed that the extracted low-frequency signals from the piezoceramic transducers had good agreement with that from the strain gauge, and the processed high-frequency signal from piezoceramic transducers as AE could indicate the local damage to concrete. The experimental results verified the feasibly of structural health monitoring using piezoceramic transducers as strain gauges and AE sensors simultaneously, which can advance their application in civil engineering.

• Bulletin of the Korean Chemical Society
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• v.19 no.8
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• pp.847-851
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• 1998

13C, 15N, and 29Si NMR chemical shifts have been computed for selected X-substituted silatranes (X=Cl, F, H, CH3) using Gauge-Including Atomic Orbitals (GIAO) and Continuous Set of Gauge Transformations (CSGT) at the Hartree-Fock level of theory. The isotropic 13C chemical shifts are largely insensitive to substituent-induced structural changes. In this study, the isotropic 13C chemical shifts GIAO and CSGT calculations at the HF/6-31G and HF/6-31G* levels are sufficiently accurate to aid in experimental peak assignments. The isotropic 13C chemical shifts X-substituted silatranes at HF/6-31G* level are approximately 4 ppm different from the experimental values. In contrast, the isotropic 15N and 29Si chemical shifts and the chemical shielding tensors are quite sensitive to substituent-induced structural changes. These trends are consistent with those of the experiment. The 15N chemical shift parameters demonstrate a very clear correlation with Si-N distance, especially when we use the polarization function. Changes in anisotropy, 3a as well as in the 15N isotropic chemical shifts are due primarily to changes in the value of a.. But in case of "Si the correlations are not as clean as for the 15N chemical shift.

• Advances in materials Research
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• v.11 no.1
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• pp.59-73
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• 2022

In the construction industry, thin-walled frame elements with very slender open cross-sections and low torsional stiffness are often subjected to a complex loading condition where axial, bending, shear and torsional stresses are present simultaneously. Hence, these often fail in instability even before the yield capacity is reached. One of the most common instability conditions associated with thin-walled structures is Lateral Torsional Buckling (LTB). In this study, a first order Generalized Beam Theory (GBT) formulation and numerical analysis of cold-formed steel lipped channel beams (C80×40×10×1, C90×40×10×1, C100×40×10×1, C80×40×10×1.6, C90×40×10×1.6 and C100×40×10×1.6) subjected to uniform moment is carried out to predict pure Lateral Torsional Buckling (LTB). These results are compared with the Finite Element Analysis of the beams modelled with shell elements using ABAQUS and analytical results based on Euler's buckling formula. The mode wise deformed shape and modal participation factors are obtained for comparison of the responses along with the effect of varying the length of the beam from 2.5 m to 10 m. The deformed shapes of the beam for different modes and GBTUL plots are analyzed for comparative conclusions.

• Journal of Distribution Science
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• v.11 no.11
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• pp.33-40
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• 2013

Purpose - This study, in seeking to understand the trade structure of both Korea and China, aims to strengthen Korea-China economic cooperation; it examines trade impediments by analyzing the problems affecting trade and addressing these problems, thereby discovering ways to expand trade between these countries. Research Design, Data, and Methodology - The index of trade intensity developed by the trade intensity theory (Kruger, 1997) is used to analyze the trade decision factors of both countries. Although specific factors should have materialized from the analysis of trade decision factors, determining concrete explanations is difficult in reality, as there are many unsolved and diverse factors. Results - First, the index of A value/B value is the index of Korean versus Chinese market share/Korean versus world market share, which is a measure of comparative market intensity. Second, Korea has a comparative advantage in export specialization and, conversely, China has a comparative advantage in import specialization. Third, compared to 2000, the revealed comparative advantage (RCA) indexes are considerably improved. Conclusions - This study used quantitative measurement for analysis, applying trade intensity theory, trade specialization, and RCA indexes to gauge how inter-trade relations have changed between Korea and China during the past 10 years (2000, 2005, and 2012).

• Journal of Navigation and Port Research
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• v.48 no.2
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• pp.78-87
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• 2024

To quantitatively assess the correlation between subsystems within a port cluster and the overall coordinated development of the port group, the current paper evaluates the coordinated development of port clusters. First, we construct an evaluation index system for the coupling and coordination of port clusters. Next, we introduce the contribution index of port subsystems, coupling degree, and coupling coordination degree functions to formulate a coupling coordination evaluation model for the port cluster. Finally, we use the Yangtze River Delta port cluster as a case study for validation, specifically using empirical data from 2012 to 2021. The findings reveal distinct phased characteristics in the coupling and coordination of port clusters in the Yangtze River Delta, marked by a notable transition from "maladjustment" to "coordination." Further, sustained high coupling values over a decade indicate a significant level of competition and cooperation among ports within the Yangtze River Delta port cluster. Over time, this competitive and collaborative dynamic has progressively evolved toward a more positive and structured direction. Lastly, it is expected that the evaluation model proposed in this paper can be extrapolated to other port clusters to gauge the extent of coordinated development, thereby facilitating horizontal comparisons and vertical analyses.

• Journal of applied mathematics & informatics
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• v.6 no.2
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• pp.329-368
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• 1999

This paper surveys recent remarkable progress in the study of potential theory for symmetric stable processes. It also contains new results on the two-sided estimates for Green functions Poisson kernels and Martin kernels of discontinuous symmetric $alpha$ -stable process in bounded $C^{1,1}$ open sets. The new results give ex-plicit information on how the comparing constants depend on pa-rametrer $alpha$ and consequently recover the green function and Poisson kernel estimates for Brownian motion by passing $alpha{\uparrow}2$. In addition to these new estimates this paper surveys recent progress in the study of notions of harmonicity integral representation of harmonic func-tions boundary harnack inequality conditional gauge and intrinsic ultracontractivity for symmetric stable processes. Here is a table of contents.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.517-522
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• 2000

In the past few years, the nondestructive inspection technology has greatly developed due to the increased necessity to gain a complete understanding of the bridge behavior. Especially, the deformations of bridges contain a lot of informations about its health state. By measuring these deformations it is possible to analyze the loading and aging behavior of the structure. However, the current methods (such as LVDT, dial gage, optical displacement tranceducer, etc) are often of changeable application on site and have the limitations of installation. In this paper, the classical beam theory was reviewed and the deflections of structure are estimated using measured strain which is easy to acquire. The applicability of this algorithm is verified by a preliminary steel beam test and two types of concrete beam tests. Also fiber optic sensors as well as resistive strain gages were installed in the concrete beams to establish the applicability of fiber optic sensors in the field of civil engineering.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.21-21
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• 2000

The Josephson Plasma resonance in single crystalling Bi2Sr2CaCu2O8 has been investigated at a microwave frequency of 35 GHz in a cavity resonator. A sharp resonance is observed in a perpendicular oscillating magnetic field. The former is independent of the sample dimension, shile the latter shift to higher field as the sample size L is reduced, and it disappears when L becomes smaller than the critical length. The longitudinal plasma mode is a Nambu-Goldston mode in a superconductor, the experimental distinction between the longitudinal and the transverse mode leads to the conclusion that the existence of the Nambu-Goldston mod as predicted by Anderson was experimentally confirmed by direct observation of the Josephson plasma resonance with longitudinal excitations. The finite gap found in Josephson plasma resonance also provides a direct proof of the Anderson-Higgs mechanism within the context of the spontaneously broken phase symmetry of the Gauge-field theory in a superconductor.