• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.872-875
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• 2004

In this paper, thermal response analysis of a temperature controlled three-axis accelerometer for high temperature environments with integrated micro-heaters and temperature sensors is investigated with finite element method (FEM) program, ANSYS and infrared thermal measurement systems. And availability to application fields from a viewpoint about short thermal response time is discussed. In this paper, the time of three-axis accelerometer for high temperatures becoming $300^{\circ}C$ by integrated micro-heaters and temperature sensors to reduce thermal drift characteristics was analyzed as a thermal response time of this device. The simulated thermal response time (time until SOI piezoresistors actually becomes $300^{\circ}C$) of three-axis accelerometer for high temperatures with ANSYS is about 0.6s, and measured result with infrared temperature measurement systems is about 0.64s. Experimental results using infrared thermal measurement systems agreed well with these theoretical results.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.11
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• pp.154-162
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• 1997

A real time error compensation system was developed to improve the quasistatic volumetric accuracy of a machining center by using sensing, metrology, modeling, and computer control techniques. Including thermal errors, 32 error components are formulated in the time-space domain. Fifteen thermal sensors are used to characterize the temperature field of the machine. A compensation controller based on the IBM/PC has been linked with a CNC controller to compensate for machine errors in real time. The maximum linear displacement error in 4 body diagonals were reduced from 140 ${\mu}m$ to 34.5${\mu}m$ with this compensation system, and the spindle thermal drift in space was reduced from 147.3 ${\mu}m$ to 16.8 ${\mu}m$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.144-147
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• 2003

Cu+ ions drift diffusion in formal oxide film and SiOCH film for interlayer dielectric is evaluated. The diffusion is investigated by measuring shift in the flatband voltage of capacitance/voltage measurements on Cu gate capacitors after bias temperature stressing. At a field of 0.2MV/cm and temperature $200^{\circ}C,\;300^{\circ}C,\;400^{\circ}C,\;500^{\circ}C$ for 10min, 30min, 60min. The Cu+ ions drift rate of $SiOCH(k=2.85{\pm}0.03)$ film is considerable lower than termal oxide. As a result of the experiment, SiOCH film is higher than Thermal oxide film for Cu+ drift diffusion resistance. The important conclusion is that SiOCH film will solve a causing reliability problems aganist Cu+ drift diffuion in dielectric materials.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.194-198
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• 2012

In this work, we studied the microstructural changes of ITO during the annealing process. ITO nanoparticles were prepared by the sol-gel method using indium tin hydroxide as the precursor. The prepared sample was investigated using TEM, powder XRD, XPS, DRIFT, and 2D correlation analysis. The O 1s XPS spectra suggested that the microstructural changes during the annealing process are closely correlated with the oxygen sites of the ITO nanoparticles. The temperature-dependent in situ DRIFT spectra suggested that In-OH in the terminal sites is firstly decomposed and, then, Sn-O-Sn is produced in the ITO nanoparticles during the thermal annealing process. Based on the 2D correlation analysis, we deduced the following sequence of events: 1483 (due to In-OH bending mode) ${\rightarrow}$ 2268, 2164 (due to In-OH stretching mode) ${\rightarrow}$ 1546 (due to overtones of Sn-O-Sn modes) ${\rightarrow}$ 1412 (due to overtones of Sn-O-Sn modes) $cm^{-1}$.

• Korean Journal of Optics and Photonics
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• v.16 no.6
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• pp.547-552
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• 2005

We have fabricated and characterized optical delay lines for optical coherence tomography, which is composed of cylindrical PZT(piezoelectric transducer) and single mode optical fiber. The polarization mode dispersion from the optical delay lines was compensated by the polarization controllers. By applying the duplex optical delay line, we minimized the thermal drift due to optical delay lines and obtained the scan range of 2 times that of a single optical delay line. The OCT system showed resolution of $18.6\pm0.5{\mu}m$, scanning range of 1.68mm, and scanning speed of 360.4mm/s.

• The KSFM Journal of Fluid Machinery
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• v.10 no.5
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• pp.54-63
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• 2007

A barrel is a high length-to-diameter ratio cylinder that is influenced by environmental factors such as sunlight, precipitation, wind and clouds. Cross-barrel temperature differences caused by uneven heating or cooling lead to thermal deformation that degrades accuracy. Therefore, a barrel is covered by thermal shrouds to minimize the type of thermal deformation, "fall-of-shot". In this paper, an analytical and experimental study is presented to design the thermal shrouds for a gun barrel and to evaluate the thermal shroud effect. First, an analytical study on the thermal shroud effect to minimize thermal deformation of a gun barrel by sunlight and wind is performed. The coupled analysis of thermal fluid dynamics of the air flow between a barrel and thermal shrouds and thermal stresses of a barrel Is performed to clarify both the thermal shroud effect and the drift in gun muzzle orientation by thermal deformation. Second, experiments are carried out to test and evaluate the thermal shroud effect on the performance of a gun barrel. The drift in gun muzzle orientation against the solar radiation is confirmed by the experiments, and the results well agree with the analytical estimation. Third, three principal design factors that are presumed to have an effect on the performance of the thermal shrouds are also analyzed; sorts of shroud materials, wall-thickness of thermal shrouds, and distance of the gap between a barrel and thermal shrouds.

• 전기의세계
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• v.14 no.6
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• pp.1-7
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• 1965

This paper provides the analysis of the differential amplifier using the insulated gate, metala-oxide-semiconductor type field-effect-transistor(MOS FET), for its active element and the power drift of the amplifer. From these analytical considerations some design standardsn were found for the MOS FET differential amplifier available for the measurement of the very small current (pico-ampare range). A differential amplifier was designed and built in the view of above considerations. Its equivalent input gate voltages of the thermal drift and the power drift were 0.57mV/.deg. C in the range 25.deg. C-60.deg. C and 8.8mV/V in the range of 20% drift of its orginal value, respectively.

• Journal of Magnetics
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• v.19 no.2
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• pp.151-154
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• 2014

Recent years have seen an increasing range of planar Hall resistive (PHR) sensor applications in the field of magnetic sensing. This study describes a new application of the PHR sensor to monitor a current. Initially, thermal drift experiments of the PHR sensor are performed, to determine the accuracy of the PHR signal output. The results of the thermal drift experiments show that there is no considerable drift in the signals attained from 0.1, 0.5, 1 and 2 mA current. Consequently, the PHR sensor provides adequate accuracy of the signal output, to perform the current monitoring experiments. The performances of the PHR sensor with bilayer and trilayer structures are then tested. The minimum detectable currents of the PHR sensor using bilayer and trilayer structures are $0.51{\mu}A$ and 54 nA, respectively. Therefore, the PHR sensor having trilayer structure is the better choice to detect ultra low current of few tens nanoampere.

• Nuclear Engineering and Technology
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• v.40 no.5
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• pp.387-396
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• 2008

Many experimental analyses for annular film dryouts, which is one of the Critical Heat Flux (CHF) mechanisms, have been performed because of their importance. Numerical approaches must also be developed in order to assess the results from experiments and to perform pre-tests before experiments. Various thermal-hydraulic codes, such as RELAP, COBRATF, MARS, etc., have been used in the assessment of the results of dryout experiments and in experimental pre-tests. These thermal-hydraulic codes are general tools intended for the analysis of various phenomena that could appear in nuclear power plants, and many models applying these codes are unnecessarily complex for the focused analysis of dryout phenomena alone. In this study, a numerical model was developed for annular film dryout using the drift-flux model from uniform heated tube geometry. Several candidates of models that strongly affect dryout, such as the entrainment model, deposition model, and the criterion for the dryout point model, were tested as candidates for inclusion in an optimized annular film dryout model. The optimized model was developed by adopting the best combination of these candidate models, as determined through comparison with experimental data. This optimized model showed reasonable results, which were better than those of MARS code.

• Nuclear Engineering and Technology
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• v.45 no.4
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• pp.439-458
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• 2013

REX-10 is a fully-passive small modular reactor in which the coolant flow is driven by natural circulation, the RCS is pressurized by a steam-gas pressurizer, and the decay heat is removed by the PRHRS. To confirm design decisions and analyze the transient responses of an integral PWR such as REX-10, a thermal-hydraulic system code named TAPINS (Thermal-hydraulic Analysis Program for INtegral reactor System) is developed in this study. Based on a one-dimensional four-equation drift-flux model, TAPINS incorporates mathematical models for the core, the helical-coil steam generator, and the steam-gas pressurizer. The system of difference equations derived from the semi-implicit finite-difference scheme is numerically solved by the Newton Block Gauss Seidel (NBGS) method. TAPINS is characterized by applicability to transients with non-equilibrium effects, better prediction of the transient behavior of a pressurizer containing non-condensable gas, and code assessment by using the experimental data from the autonomous integral effect tests in the RTF (REX-10 Test Facility). Details on the hydrodynamic models as well as a part of validation results that reveal the features of TAPINS are presented in this paper.