Study on a Temperature Scale from 24,5561 K to 273,16 K by Comparison Calibration

Kazuaki Kodaira 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

A comparison calibration apparatus using a GM cryocooler was developed. This apparatus has the structure that temperature changes of the cryocooler do not conduct directly to improve the temperature stability. A practical temperature scale from 24,5561 K to 273,16 K was examined by using the comparison calibration apparatus. Generally, a standard platinum resistance thermometer (SPRT) is calibrated at the triple points of hydrogen, neon, oxygen, argon, mercury and water in the international temperature scale of 1990 (ITS-90) for this temperature range. In this work, a capsule type SPRT was calibrated by comparison calibration method at the temperature close to these fixed point temperature. And the temperature scale using the results of the comparison calibration was compared with the temperature scale defined in the ITS-90. As a result, two temperature scales corresponded within 1,5 mK.

Infrared Camera Calibration in the 3D Temperature Field Reconstruction

Sun Xiaoming,Wu Haibin,Wang Wei,Liubo,Cui Guoguang 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.6

In order to reconstruct the 3D temperature field based on the binocular vision system, we carry out a research on the calibration of the infrared camera. To start with, we make a calibration board which can be clearly identified by the infrared camera; then, with the help of OpenCV, we implement the calibration of two infrared cameras respectively and rectify the infrared images. According to the parameters obtained from the single infrared camera calibration, we accomplish the stereo calibration. The experimental results show that the average reprojecting error is below 0.14 pixels and when using the system to carry out a real measurement, the average error is 3.12%. The feasibility of the proposed calibration approach is verified, the experimental measurement results is close to the ground truth.

Development of variable temperature instrument for sensor calibration

최연석 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.2

An experiment to calibrate temperature sensors at cryogenic temperature has been performed. The main objective of this study was todevelop a precise instrument for calibrating the temperature sensors over a temperature range of 4 K to approximately room temperaturewithout liquid helium. The instrument consists of radiation shields, a sensor block, an electric heater, a cryocooler and a vacuum chamber. In a vacuum chamber, the cold head of the cryocooler is thermally anchored to the sensor block to bring the apparatus to a desired temperature. An electric heater is placed at the second stage of the cryocooler to control the temperature of the sensor block. The entire apparatusis covered by radiation shields and wrapped in multi-layer insulation to minimize thermal radiation in a vacuum chamber. The dimensionsof components including instrumental wires are optimized to reduce total heat invasion from room temperature into cryogenictemperature. The vacuum chamber is pumped down and cooled to cryogenic temperature by a cryocooler. The resistance of each temperaturesensor is measured at steady state as well as cooling down and warming up cycles, and the performance of calibration is discussedwith respect to the sensitivity and resolution.

극저온(20K) 수소동위원소 흡착 등온선의 온도 변화에 대한 자동 저온 부피 교정

박재우,오현철,Park, Jawoo,Oh, Hyunchul 한국재료학회 2019 한국재료학회지 Vol.29 No.5

The gas adsorption isotherm requires accurate measurement for the analysis of porous materials and is used as an index of surface area, pore distribution, and adsorption amount of gas. Basically, adsorption isotherms of porous materials are measured conventionally at 77K and 87K using liquid nitrogen and liquid argon. The cold volume calibration in this conventional method is done simply by splitting a sample cell into two zones (cold and warm volumes) by controlling the level sensor in a Dewar filled with liquid nitrogen or argon. As a result, BET measurement for textural properties is mainly limited to liquefied gases (i.e. $N_2$ or Ar) at atmospheric pressure. In order to independently investigate other gases (e.g. hydrogen isotopes) at cryogenic temperature, a novel temperature control system in the sample cell is required, and consequently cold volume calibration at various temperatures becomes more important. In this study, a cryocooler system is installed in a commercially available BET device to control the sample cell temperature, and the automated cold volume calibration method of temperature variation is introduced. This developed calibration method presents a reliable and reproducible method of cryogenic measurement for hydrogen isotope separation in porous materials, and also provides large flexibility for evaluating various other gases at various temperature.

MgO 분말을 이용한 고온 X-ray 회절 실험의 시료 온도 보정 연구

김봉주,김복기,권대영,우영수,조준용 한국물리학회 2008 새물리 Vol.56 No.3

A temperature-calibration method for X-ray powder scattering using a MgO powder has been demonstrated experimentally. The temperature-dependent lattice parameter of the MgO standard material is well known. By adding 5 \% MgO as a calibration material, we performed X-ray scattering measurement on a 0.2(BiZn$_{0.5}$Ti$_{0.5}$O$_3$)-0.8(PbTiO$_3$) sample to check the structural phase transition. A full-pattern rietveld refinement was applied to obtain the lattice constant of the MgO powder. The exact temperature of the specimen could be obtained from a polynomial fitting of the lattice constant of the MgO powder at each temperature. The current method can be generally applied to various X-ray experiments at high temperatures. 우리는 MgO 분말을 이용하여 고온 XRD 실험의 시료 온도 보정 연구를 하였다. 온도를 변화시켜 가며 X-ray 회절 실험을 수행 함으로서 결정구조가 온도에 따른 변화를 연구할 때, 정확한 시료온도를 알기 위해서, 각 온도에 따른 정확한 격자 상수가 알려진 MgO 분말의 자료를 이용하여, MgO 분말의 온도에 따른 격자상수를 2차 함수로 산출하였다. 시료에 약 5 \% 의 MgO 분말을 첨가하여, 15$^\circ$ $\sim$ 135 $^\circ$ 의 전 $2\theta$ 영역에서 회절 실험을 수행하였고, 그 결과를 Rietveld refinement 분석을 하여, 시료 내에 섞여 있는 MgO 분말의 정확한 격자 상수를 얻었다. 이와 같은 방법을 이용하여, MgO의 온도를 먼저 정하고, 이에 따른 시료의 온도를 다른 실험들과 비교하여 정확한 실험이 되는 것을 확인하였다.

Evaluation of high-temperature Vickers hardness using instrumented indentation system

Park, Chan-Pyoung,Lee, Jung-Jun,Kang, Seung-Kyun,Kim, Young-Cheon,Woo, Kwan-Sik,Jeon, Seung-Won,Kwon, Dongil Elsevier 2016 Materials science & engineering. properties, micro Vol.650 No.-

<P><B>Abstract</B></P> <P>Instrumented indentation testing is more advanced than conventional hardness testing in measuring various mechanical properties of materials. To evaluate these mechanical properties, information about indentation contact area is required. In particular, the deformation behavior of metals at high-temperatures seems to differ from that at room temperature, and thus for accurate evaluation of mechanical characteristics at high-temperatures, the high-temperature contact area should be used. In this study, an instrumented indentation system for high-temperatures was developed and measurement-errors caused by equipment temperature were calibrated. In addition, the pileup effect during indentation was studied at different temperatures. A new equation for the high-temperature contact area is proposed. For verification, conventional hardness testing was performed to compare the results with high-temperature instrumented indentation testing.</P>

CTD 교정과 불확도 평가

이정한,황근춘,김은수,이승훈 한국해양과학기술원 2014 Ocean and Polar Research Vol.36 No.1

The quality control of ocean observations data is becoming a major issue as real-time observational data and information services have increased recently. Therefore, it is necessary for oceanographic instruments to calibrate. In this paper, we first introduce the CTD calibration system and traceability. Next, CTD calibration procedures and estimation of uncertainty of measurement are described. The expanded uncertainty (k = 2) of the temperature, pressure and conductivity are 0.003oC, 6.0 × 10−5 and 0.006 mS/cm respectively. Finally, the excellence of CTD calibration and its measurement capability has been proven by comparing the inter-calibration result of KIOST and Sea-Bird Electronics (SBE). CTD calibration residuals are less than ±0.0001oC, ±0.001 MPa, ±0.0001 S/m for SBE 3plus temperature sensor, SBE 19plus pressure sensor and SBE 4C conductivity sensor respectively.

현장계측 데이터를 이용한 일평균 대기온도 산정방법과 동상방지층 설계를 위한 동결지수 보정

조명환(Cho Myung-hwan),김낙석(Kim Nakseok),심재필(Shim Jaepill) 대한토목학회 2011 대한토목학회논문집 D Vol.31 No.3D

도로의 동상방지층을 설치하기 위하여 동결섬도(동결관입깊이)를 산정하는데, 동결지수는 0℃ 이하의 기온과 영하온도의 지속시간을 곱한 값을 연간을 통하여 누계한 수치로 표시된다. 따라서 일평균 대기 온도를 구하는 방법이 동결지수에 영향을 미칠 수 있다. 기상청의 경우 1999년을 기점으로 이전에는 1일 4회 평균 대기온도 제공하였으며, 현재는 1일 8회 평균 대기온도를 제공하고 있다. 본 연구에서는 이러한 일평균 대기온도를 산정하는 방법이 동결지수의 산정결과에 미치는 영향을 확인하기 위하여 한반도 남부(동결지수 350℃ · 일 미만) 6개 지역을 현장조건(저성토부, 절성경계부 및 절토부)에 따라 구분하여 15개소에 대하여 현장계측시스템을 구축하였다. 그리고 현장계측시스템으로부터 얻어진 대기온도를 통하여 동결지수를 산정하고 상호 비교분석 하였다. 비교분석 결과 일반적으로 1일 4회 평균 대기온도를 사용한 경우가 1일 8회 평균 대기온도를 사용하는 경우보다 약 3% 전후 큰 것으로 나타났으며, 본 연구 지역에 대한 동결지수를 결정할 때 동결지수를 보정 할 수 있는 보정식을 제안하였다. The frost depth(frost penetration) is used to install anti-frost heave layers in pavement designs. The freezing index is calculated by an annual accumulated value of multiplying the period of time with temperatures below zero, and the corresponding temperature. Therefore, the DAAT(daily average air temperature) calculation method may play an effect on the FI(freezing index). The Weather Observatory used to supply 4 average air temperatures per day, but currently supplies 8 per day. With this study, we divided the southern part(below FI=350°C · day) of the Korean peninsula into 6 areas according to site conditions(low embankment, embankment-cutting slope, and the cutting slope) and established a field measurement system for 15 positions to check the effects on the result of PI according to differing DAAT calculation methods. The air temperatures obtained by the field measurement system was used to calculate and compare the FI. As a result, the freezing index calculated based on the DAAT₄(T₄) is normally greater by 3% than the one on DAAT?(T?). In addition, the calibration equation for the freezing index using air temperatures was proposed through the research.

Measurement of local wall temperature and heat flux using the two-thermocouple method for a heat transfer tube

안태환,강지훈,정재준,윤병조 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.7

The two-thermocouple method was investigated experimentally to evaluate its accuracy for the measurement of local wall temperature and heat flux on a heat transfer tube with an electric heater rod installed in an annulus channel. This work revealed that a thermocouple flush-mounted in a surface groove serves as a good reference method for the accurate measurement of the wall temperature, whereas two thermocouples installed at different depths in the tube wall yield large bias errors in the calculation of local heat flux and wall temperature. These errors result from conductive and convective changes due to the fin effect of the thermocouple sheath. To eliminate the bias errors, we proposed a calibration method based on both the local heat flux and Reynolds number of the cooling water. The calibration method was validated with the measurement of local heat flux and wall temperature against experimental data obtained for single-phase convection and two-phase condensation flows inside the tube. In the manuscript, Section 1 introduces the importance of local heat flux and wall temperature measurement, Section 2 explains the experimental setup, and Section 3 provides the measured data, causes of measurement errors, and the developed calibration method.

An Energy-Efficient All-Digital Time-Domain-Based CMOS Temperature Sensor for SoC Thermal Management

Young-Jae An,Dong-Hoon Jung,Kyungho Ryu,Seung-Han Woo,Seong-Ook Jung IEEE 2015 IEEE transactions on very large scale integration Vol.23 No.8

<P>We propose an all-digital on-chip time-domain temperature sensor for system-on-a-chip (SoC) thermal management. For on-chip purposes, the proposed temperature sensor achieves energy- and area-efficient and fast thermal monitoring by adopting a digitally controlled oscillator (DCO) with the frequency divider and XNOR gate to generate temperature-dependent pulse. The frequency divider with the fine delay unit allows DCO of the proposed structure to have a smaller number of delay cells than a conventional open-loop delay line while maintaining resolution. The use of DCO with frequency divider, which consists of three flip-flops, reduced the required delay line length by 16 times. XNOR gate facilitates the fast thermal monitoring by simply providing the temperature-proportional pulse without additional processing. Temperature measurement results are provided with a digital code generated by a simple counter-based time-to-digital conversion. The proposed temperature sensor is fabricated using 0.13-μm CMOS technology and achieves a low-energy consumption of 2.3 nJ at a conversion rate of 293 kHz with a resolution of 0.72 °C and an area of 0.036 mm<SUP>2</SUP>. The proposed sensor also obtains a measurement error of -2.4 °C to 2.16 °C from nine test chips over a temperature range of 20 °C-120 °C, which is suitable for SoC thermal management.</P>