• Proceedings of the Korean Nuclear Society Conference
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• 1996.11b
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• pp.669-674
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• 1996

The theory of quantum mechanics states that for any system there are a set of discrete physical states, quantum states, which corresponds a particular energy level of the system. The lowest energy the system can have, corresponding to its ground state, is not necessarily zero, but depends only on the precise microscopic nature of the system under consideration. At the absolute zero of temperature all systems will be in their lowest energy state (zero point energy) and as the system is warmed from OK, the higher energy states become occupied. The probability of occupancy of the excited states relative to that of the ground state is proportional to the absolute temperature. Therefore we can obtain nuclear dipole and quadrupole moment very accurately at ultra low temperature (<15mk) by NMR and from the destruction of anisotropy. The former is called LTNO/NMR and the latter is called LTNO (Low Temperature Nuclear Orientation). In this paper we discuss and introduce only an experimental apparatus with results of cooling power test, a helium dilution refrigerator, which can reache 8mK, and an actual technique for the experiment, a theory and results will be presented in another papers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.378-384
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• 2013

In this paper, a CMOS temperature sensor is proposed to measure the internal temperature of a chip. The temperature sensor consists of a proportional-to-absolute-temperature (PTAT) circuit for a temperature sensing part and a 4-bit analog-to-digital converter (ADC) for a digital interface. The PTAT circuit with the compact area is designed by using a vertical PNP architecture in the CMOS process. To reduce sensitivity of temperature variation in the digital interface circuit of the proposed temperature sensor, a 4-bit successive approximation (SA) ADC using the minimum analog circuits is used. It uses a capacitor-based digital-to-analog converter and a time-domain comparator to minimize power consumption. The proposed temperature sensor was fabricated by using a $0.25{\mu}m$ 1-poly 6-metal CMOS process with a 2.5V supply, and its operating temperature range is from 50 to $150^{\circ}C$. The area and power consumption of the fabricated temperature sensor are $130{\times}390{\mu}m^2$ and $868{\mu}W$, respectively.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.3
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• pp.140-151
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• 1996

In this paper, we analyze the variations of thermal characteristics of LD (laser diode) arrays packaged by a flip-chip bonding method. When we simulate the temperature distribution in LD arrays with a BEM (boundary element method) program coded in this paper, we find that thermal crosstalks in LD arrays packaged by the flip-chip bonding method increases by 250-340% compared to that in LD arrays packaged by previous methods. In the LD array module packaged by the flip-chip bonding technique without TEC (thermo-electric cooler), the important parameter is the absolute temperature of the active layer increased due cooler), the important parameter is the absolute temperature of th eactiv elayers of LD arrays to thermal crosstalk. And we find that the temperature of the active layers of LD arrays increases up to 125$^{\circ}C$ whenall four LDs, without a carefully designed heatsink, are turned on, assuming the power consumption of 100mW from each LD. In order to reduce thermal crosstalk we propose a heatsink sturcture which can decrease the temeprature at the active layer by 40%.

• Journal of Sensor Science and Technology
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• v.26 no.1
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• pp.50-55
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• 2017

The measurement of absolute humidity of gases is essential in many industries. The effect of temperature on aluminum oxide and chilled mirror dew-point hygrometers is investigated. The temperature of laboratory, pipe line, and sensor is varied and the dew point is measured by two different aluminum oxide hygrometers. In all cases, the dew point of hygrometers is increased as the temperature is elevated. The reason behind this observation is due to desorption of water from the inside of pipe line and/or sensor surroundings at elevated temperature that result in the increase of the absolute humidity. Moreover, the sensor itself shows a certain degree of temperature dependency in sensing the humidity especially at low temperature. It is also studied that chilled mirror dew-point hygrometer may indicate a higher dew point than the reference at high temperature because the cooling capability of mirror is decreased at high temperature. Our study will provide evidences in the incorporation of the temperature effect as uncertainty factors in the standard calibration procedure for dew point hygrometers.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1990.10a
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• pp.35-40
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• 1990

Temperature distribution of high pressure mercury lamp has been mesured as a function of time using spectroscopic method. Sampling signal which is synchronized by lamp voltage was used to mesure temporal line intensity at each radius. To obtain radial temprature distribution, the mesured intensity was transformed into radial line intensity by Abel's formula. Absolute temperature profile was calculater from relative intensities of spectral lines as a function of line and tube radius. The temperature profile is very similar to the electrical tube current profile.

• 전기의세계
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• v.16 no.2
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• pp.17-21
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• 1967

In reactor operation, it is widely known that the absolute stability may not exist for multiple feedback paths even though the single lumped negative temperature coefficient feedback case is clearly stable at all frequencies above those creating xenon poisoning effects. However, interesting and useful stability information may be obtained from a two-path temperature coefficient feedback which can be represented in a water-cooled, water-moderated hetergeneous reactor. In this paper, the outline of an operating stability of a reactor having two-path temperature coefficient feedback is analyzed and described neglecting poison effects.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.354-359
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• 2001

As the temperature of liquid under negative pressure approaches the absolute zero, the nucleation process due to thermal fluctuations hardly occurs. Instead of this mechanism, quantum fluctuations may lead the formation of nucleus for new phase in metastable state. In this study, the thermal as well as quantum nucleation bubble in liquid helium under negative pressure was investigated theoretically. The energy barrier against nucleation was estimated by molecular interaction due to the Londom dispersion force. It is shown that the phase transition from liquid to vapor in is possible due to the quantum tunneling below 0.2 K for Helium-4 and 0.1 K for Helium-3, at negative pressures close to the ideal tensile strength at which every liquid molecules become bubbles simultaneously.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.126-132
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• 2002

By using the reference data, the empirical equations which describe the interrelationships of explosion properties and physical properties of n-chlorinated hydrocarbons have been derived. The properties which have been correlated are the lower and upper explosive limits, the stoichiometric coefficients, the heats of combustion, the carbon numbers. Also, the new equations using the mathematical and statistical methods for predicting the temperature dependence of lower explosive limits(LEL) of chlorinated hydrocarbons on the basis of the literature data are proposed. The fire and explosion properties calculated by the proposed equations in this research were a good agrement with literature data within a few A.A.P.E.(Average Absolute Percent Error) and A.A.D.(Average Absolute Deviation.) From a given explosive properties, by using the proposed equations, it is possible to predict to the fire and explosion characteristics for the other chlorinated hydrocarbons.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.616-619
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• 2005

CALNAL team of Korea Aerospace Research Institute(KARI) performed field campaigns for absolute radiometric calibration of 1m satellite image on Daejeon and the cal/val site of Goheung. The satellite image have spatial resolution of 1m in panchromatic spectral band of 450-900nm. The performed cal/val method is the reflectance-based of vicarious calibration methods. We collected ground-based and meteology data such as temperature, surface pressure and reflectance of targets, and radiosonde data used only to test in Goheung. Data collected on each field served as input to radiative transfer codes to generate a top-of-atmosphere(TOA) radiance estimate. Derived TOA is compared with DN of overpass satellite to calculate calibration coefficient of gain and offset.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.695-697
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• 2013

In this paper, temperature sensing circuit using by MOS is proposed. It produces the voltage as output and is applicable for the internal IC temperature measurement. It is designed by two current mirrors using MOS to implement the IC in the CMOS fabrication and is applicable for the various applications. It operates in two mode, temperature mode and sleep mode. From the simulation results, output voltage is measured from 0V to 1.2V by sweeping $0^{\circ}C{\sim}125^{\circ}C$ in temperature mode and output current flows under 100pA in sleep mode.