• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.141-141
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• 2010

The effect of thermal anneal on the characteristics of structural properties and the enhancement of luminescence and photovoltaic (PV) characteristics of silicon-rich silicon-nitride films were investigated. By using an ultra high vacuum ion beam sputtering deposition, B-doped silicon-rich silicon-nitride (SRSN) thin films, with excess silicon content of 15 at. %, on P-doped (n-type) Si substrate was fabricated, sputtering a highly B doped Si wafer with a BN chip by N plasma. In order to examine the influence of thermal anneal, films were then annealed at different temperature up to $1100^{\circ}C$ under $N_2$ environment. Raman, X-ray diffraction, and X-ray photoemission spectroscopy did not show any reliable evidence of amorphous or crystalline Si clusters allowing us concluding that nearly no Si nano-cluster could be formed through the precipitation of excess Si from SRSN matrix during thermal anneal. Instead, results of Fourier transform infrared and X-ray photoemission spectroscopy clearly indicated that defective, amorphous Si-N matrix of films was changed to be well-ordered thanks to high temperature anneal. The measurement of spectral ellipsometry in UV-visible range was carried out and we found that the optical absorption edge of film was shifted to higher energy as the anneal temperature increased as the results of thermal anneal induced formation of $Si_3N_4$-like matrix. These are consistent with the observation that higher visible photoluminescence, which is likely due to the presence of Si-N bonds, from anneals at higher temperature. Based on these films, PV cells were fabricated by the formation of front/back metal electrodes. For all cells, typical I-V characteristic of p-n diode junction was observed. We also tried to measure PV properties using a solar-simulator and confirmed successful operation of PV devices. Carrier transport mechanism depending on anneal temperature and the implication of PV cells based on SRSN films were also discussed.

• Progress in Superconductivity and Cryogenics
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• v.5 no.1
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• pp.123-127
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• 2003

For disseminating a ney IEC international standard of critical trmperature of NbTi,Nb$_3$Sn and Bi-2223 Composite Suterconductors, we develpted a measuring system and studied standardization of test method. The measuring system consisted of cryogenic reservoir, base plate, thermometer, voltmeter and current source. Various specimens of the Nbti, Nb$_3$Sn and Bi-2223 composite superconductors were tested using this system for measuring their critical temperatures. After measuring the resistance-temperature relation, the data were compensated with thermoelectric voltages for NbTi Nb$_3$Sn specimens. NbTi specimens showed 9.2 K ~ 9.5 K of transition temperature and Nb$_3$Sn specimen showed about 18 K. Bi-2223 specimens showed 104 K ~ 107 K of transition temperature.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.11
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• pp.41-46
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• 2009

We present experimental data on the time response behavior of industrial platinum resistance thermometers (IPRT) to help with the selection of proper sensors in industry and research laboratories. Time constants of IPRTs were measured using a method specified in ASTM standards. Two different sensors of different protecting sheath diameters were tested in air, water and silicon oil at temperatures from $0^{\circ}C$ to $200^{\circ}C$. The time constant was the smallest in water and the highest in air. As the test temperature increased, time constants tended to decrease at all heat conducting media. For different diameters of sheath of IPRT at the same temperature, it was found that the IPRT of larger diameter showed higher time constant in air, but the opposite dependence was observed in water and oil. From the measured results, it was suggested that the sensor diameter and heat conducting medium should be considered if one wants to select proper thermometer to measure the dynamic temperature change in industry and research area.

• Journal of Sensor Science and Technology
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• v.22 no.6
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• pp.415-420
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• 2013

Calibration capabilities for thermometer calibration by comparison method were assessed using high-precision industrial platinum resistance thermometers (IPRT). It was found in the performance assessment that out of 31 laboratories who participated, 28 laboratories resulted magnitude of En number less than 1 at every calibration points they submitted results in the range from 50 to $500^{\circ}C$. The results of about 75% of the laboratories showed the difference from the assigned values less than 1/10 of the tolerance level of the class B IPRT. This indicates that the participating calibration laboratories performed with satisfactory level that was enough to calibrate IPRTs to significant precision. The sensors used in this work were manufactured and chosen by the criteria of long-term instability less than 4 mK and hysteresis less than 8 mK in the temperature range used in this work. Furthermore, the change in the resistance of the sensors in the calibration temperature range were less than the uncertainty of the calibration, 25 mK (k=2).

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.19-24
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• 2002

User-friendly-web-based database system for searching creep property data was developed. This system includes about 38000 creep data for 270 different materials including low carbon steel, stainless steel and alloy steel. Data on creep rupture, creep deformation, creep crack growth and creeping materials can be searched through this system. Retrieved data is displayed in numeric form and also presented in graphical form for visualizing the data. Furthermore, the creep rupture data is designed to be fitted to a regression equation of logarithmic stress using time-temperature parameter(TTP). The degree of the regression equation, orthogonal polynomials, was determined using analysis of variance.

• Journal of Biomedical Engineering Research
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• v.31 no.2
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• pp.123-128
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• 2010

The thermometers is widely used in diagnostic medical devices, and the safety and accurate performance of these devices are important in the diagnosis and monitoring of personal health. Especially, the accuracy of infra-red thermometer is highly emphasized. Here two typical thermometers are utilized for this purpose: the electronic thermometers measure body temperature by contacting to subject while infra-red thermometers measure by no contacting to subject. Therefore, the evaluating items of each thermometer are different, and the standard for each temperature is highly needed. But, there have been no international standards of each thermometer such as IEC. In this paper, we developed the standards of electronic and infra-red thermometer based on national standards such as KS, ASTM, EN, JIS and FDA guidance. The new standards focused on the safety and suitable performance for health care. This standards were applied to enact and revise the electronic medical device standards. So it can be applied to evaluate the safety and performance on technical file review. We predict that this standard will improve the quality of diagnostic medical devices (thermometers) and increase the international competitive power of domestic product.

• Journal of the Optical Society of Korea
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• v.7 no.2
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• pp.106-112
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• 2003

In order to do continuous health monitoring of large structures, it is necessary that the distributed sensing of strain and temperature of the structures be measured. So, we present the temperature compensation of a signal from a fiber optic BOTDA (Brillouin Optical Time Domain Analysis) sensor. A fiber optic BOTDA sensor has good performance of strain measurement. However, the signal of a fiber optic BOTDA sensor is influenced by strain and temperature. Therefore, we applied an optical fiber on the beam as follows: one part of the fiber, which is sensitive to the strain and the temperature, is bonded on the surface of the beam and another part of the fiber, which is only sensitive to the temperature, is located nearby the strain sensing fiber. Therefore, the strains can be determined from the strain sensing fiber while compensating for the temperature from the temperature sensing fiber. These measured strains were compared with the strains from electrical strain gages. After temperature compensation, it was concluded that the strains from the fiber optic BOTDA sensor had good coincidence with those values of the conventional electrical strain gages.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.644-647
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• 2009

In this paper, the study is researched for related safety standards having experiments concerning temperature changes in type IV cylinder of the Hydrogen fuel cell vehicle. Experiments were performed to acquire temperature data of type IV cylinder according to filling time. The experimental results are shown that internal temperatures of type Ⅳ vessel are over $85^{\circ}C$ at all measured points after 5 minutes at filling 35 MPa and the highest temperature is getting lower when the residual gases are more remained. Consequently, the safety standards need properly limited value through further study for filling flow rate and filling time.

• Korean Journal of Materials Research
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• v.1 no.4
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• pp.198-205
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• 1991

Sintered thermistor body was fabricated by solid reaction method using $Fe_2O_3, \;Al_2O_3, \;TiO_2$ and Si powder. Surface matrix of sintered body was investigated by SEM and $\beta$-constant was obtained from measurement of resistance variation in liquid bath. The values of thermistor constant $\beta$ of samples in the temperature range $-50~+50^{\circ}C$ were distributed from 927 to 4005k. This thermistor body can be used as temperature sensor for radiosonde.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.85-86
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• 2020

In securing durability of underground structure non-exposed waterproof materials, the company aims to improve durability of waterproof materials by studying more realistic weather conditions than KS standards and developers' durability standards. Analyzing the actual climate data in Korea and the temperature of the basement layer, it is a waterproofing sheet method, a self-adhesive sheet method in which a film and a compound, which are currently widely used as underground water-proofing, and a self-adhesive waterproofing sheet method, etc. We would like to present the guidelines necessary to prevent the temperature situation and waterproof defects that are ideal for setting the endurance conditions later.