• Journal of the Korean Vacuum Society
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• v.12 no.1
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• pp.7-15
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• 2003

Spinning Rotor Gauge (SRG) has been used to transfer standard gauge for international comparison at the high vacuum standards. We calibrated a spinning rotor gauge by using dynamic calibration system (DCS) that was a national high vacuum standards system. And its uncertainties were evaluated with the International Organization for Standardization (ISO), they were recognized ai A type uncertainty, B type uncertainty, combined Standard uncertainty, and expanded uncertainty. The combined standard uncertainties were $1.8007\times10^{-5}$ Pa ~ ~$4.8422\times10^{-5}$ Pa for this spinning rotor gauge.

• Journal of the Korean Vacuum Society
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• v.14 no.4
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• pp.186-194
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• 2005

A Spinning Rotor Gauge was calibrated between $4.04\times10^{-3}$ Pa and $1.11\times10^{-2}$ Pa at the high vacuum standard by static expansion method. The results were analysed according to the document of 'Guide to the Expression of Uncertainty in Measurement' of ISO. The expanded uncertainty was $3.0035\times10^{-3}$ Pa at $7.5448\times10^{-3}$ Pa. $95\%$ confidence level, and coverage factor of k = 1.

• Journal of the Korean Vacuum Society
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• v.15 no.4
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• pp.347-353
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• 2006

A helium permeation type standard leak calibration system has newly developed by using dynamic gas expansion method. The measurement range was extended lower to $10^{-6}$ Pa L/s for participating CCM (Consultative Committee for Mass and Related Quantities) standard leak key comparison. For the system, pressure ratios of high and ultra-high vacuum chamber and porous plug conductance for helium gas were determined. By using the system, a permeation type standard leak of $5.6{\times}10^{-4}$ Pa L/s range was calibrated. The calibration result showed that the difference between standard commercial leak was 11.1 %.

• Journal of the Korean Vacuum Society
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• v.15 no.1
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• pp.1-13
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• 2006

Vacuum laboratory in Korea Research Institute of Standards and Science (KRISS) was opened in 1983 for establishing and disseminating vacuum standard in Korea. The major three systems such as the ultrasonic interferometer manometer (UIM), the static expansion system (SES) and the dynamic expansion system (DES) with orifice and porous plug conductance are developed. In this study, the standard systems from low to ultra-high vacuum, uncertainty analysis by ISO regulation, and key and bilateral comparison results will be described.

• Applied Science and Convergence Technology
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• v.23 no.3
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• pp.103-112
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• 2014

The Korea Research Institute of Standards and Science (KRISS) has three major vacuum systems: an ultrasonic interferometer manometer (UIM; Section II, Figs. 1 and 2) for a low vacuum, a static expansion system (SES; Section III, Figs. 3 and 4) for a medium vacuum, and an orifice-type dynamic expansion system (DES, Section IV, Figs. 5 and 6) for high and ultra-high vacuum systems. For each system, explicit measurement model equations with multiple variables are given. According to ISO standards, all of these system variable errors were used to calculate the expanded uncertainty (U). For each system, the expanded uncertainties (k = 1, confidence level = 95%) and relative expanded uncertainty (expanded uncertainty/generated pressure) levels are summarized in Table 4. Within the uncertainty limits, our bilateral and key comparisons [CCM.P-K4 (10 Pa to 1 kPa)] are extensive and in good agreement with those of other nations (Fig. 8 and Table 5).

• Journal of the Korean Vacuum Society
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• v.4 no.2
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• pp.135-141
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• 1995

Spinning Rotor Gauge(SRG)를 전달표준기(transfer standard gauge)로 사용하여 한국표준과학연구원(KRISS)의 고진공표준과 이태리 표준연구소인 IMGC(Istituto 야 Metrologia Gustavo Colonnetti)고진공표준의 국제비교를 실시하였다. 그 방법은 SRG의 accommodation coefficient(s)를 각 연구실의 고진공표준기로 측정하여 그 결과를 비교하였다. 이 결과 두 기관에서 교정한 SRG 볼의 $\sigma$값의 평균차이는 0.696%로서 양국의 고진공표준은 오차범위내에서 일치하는 것으로 나타났다.

• Journal of Korean Vacuum Science & Technology
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• v.6 no.3
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• pp.109-115
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• 2002

This paper describes a CCM key comparison of low absolute-pressure standards at seven National Measurement Institutes that was carried out during the period March 1998 to September 1999 in order to determine their degrees of equivalence at pressures in the range 1 Pa to 1000 Pa. The Korea Research Institutes of Standards and Science(KRISS) participated from 10 Pa to 1000 Pa pressure range in 1999. The primary standards, which represent two principal measurement methods, included five liquid-column manometers and four static expansion systems. The transfer standard package consisted of four high-precision pressure transducers, two capacitance diaphragm gauges to provide high resolution at low pressures, and two resonant silicon gauges to provide the required calibration stability.

• Journal of Powder Materials
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• v.5 no.4
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• pp.293-298
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• 1998

In all larger hardmetal workshops furnaces for dewaxing, vacuum sintering or vacuum and overpressure sintering are today's standard. The furnace technology is well established. Equipment specifications such as operating overpressure, determine sintering cost, product quality, safety and reliability of the furnace and ultimately influence the competitiveness of the hard metal procucer in the global market. Essential furnace requirements are an efficient utilization of the furnace, an environmental friendly dewaxing system, high temperature uniformity, metallurgical treatment with process gases, as well as reduced cooling time by means of rapid cooling. Examples of reduced sintering costs are described achieved using a new design of vacuum sintering furnace with an improved rapid cooling device, cooling times are reduced by up to 45%. Additionally, a cost comparison of two different designs of vacuum overpressure sintering furnaces are included.

• KIEAE Journal
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• v.16 no.3
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• pp.121-128
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• 2016

Purpose: The vacuum glazing should constantly retain the gap in vacuum state to maintain high thermal performance. To do so, pillars are used to prevent the glazing from clinging to each other by the atmospheric pressure and therefore surface of the vacuum glazing is consistently affected by residual stress. The vacuum glazing could be applied to curtain wall systems at spandrel area to fulfill a rigorous domestic standard on U-value of the external wall. However, this can lead to high glazing temperature increase by heat concentration at a back panel and finally thermal stress breakage. This study experimentally determined weakness of the vacuum glazing systems on the thermal stress breakage and investigated effect of the residual stress. Method: The experiment first built two scale-down mock-up facilities that replicate the spandrel area in curtain wall, and then installed single low-e glass and vacuum glazing respectively. The two mock-up facilities were exposed to outside to induce the thermal stress breakage. Result: The experiment showed that the temperature occurred the thermal stress breakage was $114.4^{\circ}C$ for the single low-e glass and $118.9^{\circ}C$ for the vacuum glazing respectively. The result also showed the vacuum glazing reached the critical point earlier than the single low-e glass, which means that the vacuum glazing has high potential to occur the thermal shock breakage. In addition, the small temperature difference between two glazing indicates that the residual stress scarcely affects breakage of the vacuum glazing.

• Applied Microscopy
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• v.29 no.1
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• pp.75-81
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• 1999

Optimum conditions for making the Au and Al internal standards for TEM have been determined experimentally. The Au internal standard was produced by sputter coating at 9mA for 100 seconds in low vacuum $(\leq1\times10^{-3})$. The Al internal standard was produced by evaporation coating at 7kV for 10 minutes in high vacuum $(\leq1\times10^{-5})$. Measurements of the lattice parameters of andalusite and albite feldspars with this Au internal standard resulted in errors of (a) $ \leq1.2%$ in precion and $\leq0.3%$ in accuracy for andalusite: (b) $\leq0.5%$ in precision and $\leq1.1%$ in accuracy for albite feldspars. The most significant error occurred from the measuring processes of distances and angles of electron diffraction patterns. By employing systematic procedures of measurement with high precision devices, this lattice parameter determination method utilizing the internal standard should be a good alternative to the conventional powder XRD method or the sophisticated CBED method for special samples.