• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2007년도 제33회 하계학술대회 초록집
• /
• pp.341-341
• /
• 2007

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2007년도 제33회 하계학술대회 초록집
• /
• pp.365-365
• /
• 2007

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 1998년도 IUMRS-ICEM ABSTRACT BOOK
• /
• pp.53.4-53
• /
• 1998

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
• /
• pp.3061-3062
• /
• 2005

고정밀급 저항 및 센서류를 사용할 때 정확한 전기저항의 측정이 요구되므로 누설전류 혹은 누설저항 효과는 중요한 측정오차로 나타난다. 그 누설효과를 측정하는 두 가지 방법들에 의한 측정결과와 여기서 제안하는 방법의 결과를 서로 비교하였다. 세 가비 방법 모두 비슷한 결과를 나타내었으나 제시한 방법의 결과가 조금 더 크게 나타났다. 그 원인은 누설경로가 생기는 부분들에 대한 해석의 차이와 수 pA 정도의 적은 누설전류로 인하여 시간적으로 보다 안정된 상태에서 측정이 되어야 한다는 점에서 비롯된다고 생각된다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 C
• /
• pp.1593-1595
• /
• 2000

We present a new procedure to evaluate the degradation in a lCr-lMo-0.25V steel. The method is based on the existence of the peak of reversible permeability in the differential magnetization around the coercive field strength. The apparatus is based on the detection of the voltage induced in a surface type coil using a lock-in amplifier tuned to a frequency to the exciting one. Results obtained the reversible permeability and Vickers hardness on the annealed samples show the peak interval of reversible permeability and Vickers hardness decreased as ageing time increased. The correlation between Vickers hardness and the peak interval of reversible permeability could well be evaluated non destructively.

• Bulletin of the Korean Chemical Society
• /
• 제25권9호
• /
• pp.1301-1302
• /
• 2004

• Mass Spectrometry Letters
• /
• 제11권4호
• /
• pp.108-112
• /
• 2020

A certified reference material (CRM) for the analysis of nutrient elements in an edible mushroom (Ganoderma lyceum) powder has been developed (KRISS CRM 108-10-011). The mass fractions of calcium (Ca), iron (Fe), and zinc (Zn) were measured by isotope dilution inductively coupled plasma mass spectrometry (ID ICP/MS). To dissolve the fungi cell wall of mushroom consisted of chitin fibers, sample preparation method by single reaction chamber type microwave-assisted acid digestion with acid mixtures was optimized. The mean measurement results obtained from 12 sample bottles were used to assign as the certified values for the CRM and the between-bottle homogeneities were evaluated from the relative standard deviations. The certified values were metrologically traceable to the definition of the kilogram in the International System of Units (SI). This CRM is expected to be used for validation of analytical methods or quality control of measurement results in analytical laboratories when they determine the mass fractions of elements in mushroom or other similar samples.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.645-648
• /
• 2005

Microscopy has enabled the development of many advanced technologies, and higher level microscopic techniques are required according to the increase of research in nano-technology and bio-technology fields. Therefore, in many applications, we need to measure the dimension of micro-scale parts accurately, not just to observe their shapes. To establish the meter-traceability in microscopy, gratings have been widely used as a magnification standard. KRISS provides the certification service of magnification standards using an optical diffractometer and a metrological AFM (MAFM). They are based on different measurement principles, and so can give complementary information for each other. In this paper, we describe the configuration of each system and measurement procedures to certificate grating pitch values of magnification standards. Several measurement results are presented, and the discussion about them are also given. Using the optical diffractometer, we can calibrate a grating specimen with uncertainty of less than 50 pm. The MAFM can measure a grating specimen of down to 100 nm pitch value, and the calibrated values usually have uncertainty less than 500 pm.

• Mass Spectrometry Letters
• /
• 제9권4호
• /
• pp.105-109
• /
• 2018

A certified reference material (CRM) for the analysis of inorganic nutrients in nutritional supplements has been developed. Accurate mass fractions of chromium (Cr), iron (Fe), copper (Cu), and zinc (Zn) were determined by isotope dilution inductively coupled plasma mass spectrometry (ID ICP/MS). The measurement results were used to assign certified values for the CRM, which were metrologically traceable to the definitions of the measurement units in the International System of Units (SI). Production of a candidate reference material (RM) and the certification processes are summarized. Each nutrient in the CRM showed good homogeneity, which was estimated using relative standard deviations of the measurement results of twelve bottles in a batch. This CRM is expected to be an important reference to improve reliability and comparability of nutrient analyses in nutritional supplements and related samples in analytical laboratories.

• Journal of Positioning, Navigation, and Timing
• /
• 제12권2호
• /
• pp.201-209
• /
• 2023

Time comparison techniques are required for generating and keeping Coordinated Universal Time (UTC) and to distribute standard clocks. These techniques play an important role in various fields, including science, finance, military, and communication. Among these techniques, Two-Way Satellite Time and Frequency Transfer (TWSTFT) ensures a relatively high accuracy, with a time comparison accuracy at a nanosecond level. However, TWSTFT systems have some limitations, such as the dependency on extra network links. In this paper, we propose an improved method for TWSTFT system operation and design a message structure for the suggestion. Additionally, we estimate the data rate and redundancy for the new TWSTFT signal with the designed message structure.