• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.2
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• pp.151-156
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• 2008

Many kinds of mass spectrometer type leak detectors have been widely used for detecting leak of vacuum processes in semiconductor and display industries etc. The leak detectors should be often calibrated by the permeation type standard leak in order to ensure accurate and reproducible leak measurement. We have developed a comparative calibration system for permeation type standard leak by using mass spectrometer type leak detector and specification of the calibration method. Following this technique the reliable calibration for leak standard ran be performed even in fields.

• Food Science and Preservation
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• v.19 no.6
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• pp.807-812
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• 2012

This study was investigated the changes in quality of heat treated fresh-cut lotus roots using various packaging materials. Lotus roots were purchased from Daegu, Korea. Lotus roots were washed, peeled and sliced with a sharp ceramic knife. The prepared peeled and sliced lotus roots were dipped for 45 sec in water at $55^{\circ}C$. After air-dried at room temperature, the slices were packaged with polyethylene films, polyethylene terephthalate tray+wrapping, vacuum packaging and then stored at $4^{\circ}C$. Changes in weight loss, color, firmness, microorganisms and sensory characteristics were measured. In general, the weight loss rate was increased slightly in vacuum packaged lotus roots. Application of heat treatment delayed browning of lotus roots, and especially vacuum packaged lotus roots were the most lowest ${\Delta}E$ value. However, L and ${\Delta}E$ value of PE film packaged lotus roots were increased highly during storage. The heat treated and vacuum packaging inhibited the growth of microorganisms effectively. The organoleptic quality of vacuum packaged lotus roots showed the best by sensory evaluation.

• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.632-644
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• 2022

Purpose To determine the incidence of atypical ductal hyperplasia (ADH) in needle biopsy and the upgrade rate to carcinoma, and to evaluate difference in findings between the upgrade and non-upgrade groups. Materials and Methods Among 9660 needle biopsies performed over 48 months, we reviewed the radiologic and histopathologic findings of ADH and compared the differences in imaging findings (mammography and breast US) and biopsy methods between the upgrade and non-upgrade groups. Results The incidence of ADH was 1.7% (169/9660). Of 112 resected cases and 30 cases followed-up for over 2 years, 35 were upgraded to carcinoma (24.6%, 35/142). The upgrade rates were significantly different according to biopsy methods: US-guided core needle biopsy (USCNB) (40.7%, 22/54) vs. stereotactic-vacuum-assisted biopsy (S-VAB) (16.0%, 12/75) vs. USguided VAB (US-VAB) (7.7%, 1/13) (p = 0.002). Multivariable analysis showed that only US-CNB (odds ratio = 5.19, 95% confidence interval: 2.16-13.95, p < 0.001) was an independent predictor for pathologic upgrade. There was no upgrade when a sonographic mass was biopsied by US-VAB (n = 7) Conclusion The incidence of ADH was relatively low (1.7%) and the upgrade rate was 24.6%. Surgical excision should be considered because of the considerable upgrade rate, except in the case of US-VAB.

• Journal of the Korean Society of Radiology
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• v.18 no.1
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• pp.45-52
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• 2024

In this study, an AI-based algorithm was developed to prevent image quality deterioration and reading errors due to patient movement in PET/CT examinations that use radioisotopes in medical institutions to test cancer and other diseases. Using the Mothion Free software developed using, we checked the degree of correction of movement due to breathing, evaluated its usefulness, and conducted a study for clinical application. The experimental method was to use an RPM Phantom to inject the radioisotope 18F-FDG into a vacuum vial and a sphere of a NEMA IEC body Phantom of different sizes, and to produce images by directing the movement of the radioisotope into a moving lesion during respiration. The vacuum vial had different degrees of movement at different positions, and the spheres of the NEMA IEC body Phantom of different sizes produced different sizes of lesions. Through the acquired images, the lesion volume, maximum SUV, and average SUV were each measured to quantitatively evaluate the degree of motion correction by Motion Free. The average SUV of vacuum vial A, with a large degree of movement, was reduced by 23.36 %, and the error rate of vacuum vial B, with a small degree of movement, was reduced by 29.3 %. The average SUV error rate at the sphere 37mm and 22mm of the NEMA IEC body Phantom was reduced by 29.3 % and 26.51 %, respectively. The average error rate of the four measurements from which the error rate was calculated decreased by 30.03 %, indicating a more accurate average SUV value. In this study, only two-dimensional movements could be produced, so in order to obtain more accurate data, a Phantom that can embody the actual breathing movement of the human body was used, and if the diversity of the range of movement was configured, a more accurate evaluation of usability could be made.

• Journal of the Korean Society of Radiology
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• v.83 no.1
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• pp.54-69
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• 2022

Early detection of potential asymptomatic coronary artery disease is very important, as patients with sudden cardiac death often do not show symptoms such as chest pain or motor dyspnea. Coronary CT angiography (CCTA) has long been unjustified as a screening tool for asymptomatic patients because of the risks posed by radiation exposure. However, there are still various opinions regarding the usefulness of CCTA for screening for coronary artery disease (CAD) in asymptomatic healthy individuals or patients. This review investigated the usefulness of coronary artery calcium score and CCTA as screening tests for CAD in asymptomatic healthy individuals or patients through various literature reviews. With the development of CT technology, recent studies have been conducted in asymptomatic CAD patients with a reduced radiation dose of less than 1 mSv. A total of 2.6% of asymptomatic subjects on CCTA found significant CAD over 70%, and it was concluded that screening CCTA for CAD showed prognostic power in predicting the future occurrence of CAD in asymptomatic people. However, after the completion of the current NIH SCOT-HEART 2 study, it may be possible to determine whether CCTA is appropriate as a screening tool for CAD in asymptomatic healthy individuals.

• Journal of the Korean Vacuum Society
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• v.17 no.5
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• pp.466-472
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• 2008

Purple Gold is the alloy consisting of 78wt%Au-22wt%Al, and is expressed as a chemical formula, $AuAl_2$. Lately it is being used for the material of accessories or the decorative ornaments, being one of the colored golds having the peculiar purple color, like White Gold and Pink Gold. Purple Gold has the weak point in shaping through casting process due to the bad malleability and castability, being the intermetalic compound of Au and Al. Therefore, it is possible to produce the final product only by the cutting and the grinding process or to use it as a decorative coat with the thin film evaporation. This study implemented two kinds of thin film experiments. One is the case that heat treatment was made after Au and Al deposition evaporated separately with a weight ratio 78:22 on the 200nm$SiO_2$/Si substrate. The other is the case that the surface deposition was made through the vacuum evaporation, keeping the glass substrate temperature remain room temperature, using the bulk $AuAl_2$ as a source. The final film property was measured, focusing on the Purple Gold's color and thickness through the bare eye inspection, the microstructure analysis, the surface resistance analysis, the color difference analysis, and XRD analysis. Purple Gold was not formed, as the excessive surface agglomeration occurred, in case of being produced and treated thermally with 12.5nmAu/40nmAl/200nm$SiO_2$/Si structure. Our results suggest that of Purple Gold films, showing the same purple color as the bulk's, were successfully deposited with the direct thermal evaporation from the $AuAl_2$ bulk source.

• Proceedings of the KAIS Fall Conference
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• 2008.05a
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• pp.43-45
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• 2008

박막 제작공정은 반도체 제작 공정, 고정밀도의 하드디스크 및 레이저 디스크 기술, LCD/P에 DML평판 디스크 플레이어 제작 공정에 있어 중요한 기술이다. 더욱이, 이 공정은 이동 전화 커버의 증착 및 전자 차폐의 일반기술, 램프의 반사판, 화장품 용기, 몇몇 상품에 있어 카메라 렌즈의 광학 표면 코팅과 코팅 필름 제작에 사용된다. 본 연구의 주요목적은 반도체 제작 공정과 많은 산업 분야에서 기본 재료로 사용되는 전영저항의 개발에 있다. 개발 공정은 다음과 같다. 전자빔이 최상의 진공 분위기에서 텅스텐 필라멘트의 열에 의해 방출된다. 그때 전자는 높은 전압에서 가속화된다. 전자들은 반대 재료에 충돌되고, 반대편 재료는 발생 열에 의해 코팅된다. 1차년도 연구목적은 고성능 전열 저항체 개발을 위한 지름 당 필라멘트 선의 기계적 특성을 조사하고 CAE 해석을 수행하며, 2차 년도에는 대량 생산 라인 구축을 위한 자동검사 라인 개발에 초점이 맞추어져 있다. 만일, 본 연구를 통해 전열 저항체가 개발된다면, 그 제품은 고효율, 외국제품 대비 가격 경쟁력을 가지므로 제품 경쟁력을 가질 수 있을 것으로 생각된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.996-999
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• 2020

노후 선박의 증가로 선체 검사의 필요성이 높아지고 있다. 하지만 선체 벽면의 균열을 찾고 보수하는 작업은 위험성이 높고 효율성이 낮다. 이에 본 논문에서는 선체의 벽면에 진공 흡착하여 장애물에 부딪히지 않고 선체 벽면을 이동하면서 균열을 탐지하는 로봇을 개발하였다. 선체 균열탐지 로봇은 선체뿐만 아니라 사람이 직접 균열을 찾기 힘들거나 위험한 곳에 유용할 것이며 균열로 인한 선박 사고 발생을 줄여줄 것으로 기대된다.

• Applied Biological Chemistry
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• v.48 no.2
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• pp.120-127
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• 2005

Electron beam irradiation was applied to examine the microbial growth and qualities of vacuum-packaged chicken breasts. Chicken breast samples were irradiated at dose of 2, 4, 8, 12, and 16 kGy, respectively. After irradiation, chicken breast samples were individually vacuum-packaged and stored at $4^{\circ}C$. Microbiological change of irradiated vacuum-packaged chicken breasts showed that populations of total bacteria, yeast and mold, total coliform, and salmonella spp. in chicken breasts were significantly reduced with increasing irradiation dose. The pH values of vacuum-packaged chicken breasts were not significantly changed among treatments. Lipid oxidation measurements showed that TBARS values of vacuum-packaged chicken breasts increased with increase of irradiation dose, and gradually increased during storage. Color measurements showed that irradiation reduced Hunter a value of vacuum-packaged chicken breasts with increasing irradiation dose. However, Hunter L and b values of vacuum-packaged chicken breasts were not significantly altered among treatments. Sensory quality results of vacuum-packaged chicken breasts showed that there were no significant changes among the samples irradiated. These results indicate that irradiation can be used to improve the microbial safety and qualities of poultry products.

• Food Science and Preservation
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• v.15 no.3
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• pp.340-346
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• 2008

This study investigated the microbial safety of apple snails and intermediate-moisture-content apple snail products subjected to various treatments, according counts of total bacteria, Escherichia coli, mold and yeast during storage at 4C Heating of raw apple snails at 95C for 5 min increased the storage period in relation to total bacteria, E. coli, mold and yeast-cell growth. Addition of 10% NaCl and 50% vinegar increased the microbial safety of apple snails. Microorganisms were not detected for 14 weeks in vacuum-packaged intermediate-moisture-content apple snail products stored at either 4C or 30C. These results suggest that heat treatment of raw apple snails, soaking in 10% NaCl and 50% vinegar solutions, and vacuum-packaging increases the shelf-life and microbial safety of apple snail products.