• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.104-107
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• 2019

현대인들은 과거에 비해 풍부한 먹거리와 다양한 삶의 형태를 가지게 되었으나 바쁜 생활 속에 아침을 거르게 되고, 제 시간에 식사를 하지 못하는 등의 올바르지 못한 식습관을 형성하게 되었다. 이러한 식습관은 장기간 유지되면서 소화기관 장애로 이어지게 된다. 그에 가장 쉽게 발생하는 증상이 역류성 식도염과 삼킴 장애라고 불리는 연하 곤란이 있으며, 그 중 연하 곤란은 다양한 합병증의 형태로 발전하거나 위암, 후두암등의 전조증상으로 확인되기도 하여 빠르고 정확한 진단이 요구된다. 이에 따른 진단 결과는 현재도 의사가 수동적으로 판단하며 그 결과가 제각각이다. 여기서 말하는 진단 결과는 중증 정도를 말하는 것이며, 그에 따른 치료법이나 합병증을 파악할 때의 잘못된 진단으로 과한 치료나 부족한 대처로 이어지게 될 수도 있다. 본 논문에서는 연하 곤란의 심각 정도를 파악하기 위해 연하 곤란 진단 과정에서 식도로 이어지는 구간에 후두개곡과 이상와 부에 남는 잔여 음식물을 확인하기 위한 X-ray 이미지 처리에 K-means 알고리즘을 사용하는 프로그램을 개발하는 것을 연구하였다.

• The Journal of Advanced Prosthodontics
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• 제14권6호
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• pp.335-345
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• 2022

PURPOSE. This in vitro study aimed to evaluate the surface characteristics of a full veneer crown fabricated chairside (CS) from a (Y, Nb)-TZP zirconia block in response to conventional zirconia grinding and polishing. MATERIALS AND METHODS. Zirconia crowns (n = 40) were first prepared and divided into two groups of materials: Labside (LS) and CS, after which each specimen went through a five-step grinding and polishing procedure. Following each surface treatment, surface characteristics were analyzed using confocal laser microscopy (CLSM), average surface roughness (Ra) values were processed from the profile data through Gaussian filtering, and X-ray diffraction pattern analysis was performed to evaluate the monoclinic (M) phase content. Then, a representative specimen was selected for field-emission scanning electron microscopy (FE-SEM), followed by a final analysis of the roughness and X-ray diffraction of the specimens using the independent t-test and repeated measures analysis of variance (RM-ANOVA). RESULTS. In every group, polishing significantly reduced the Ra values (P < .001). There was no significant difference in Ra between the polished state CS and LS. Furthermore, CLSM and FE-SEM investigations revealed that even though grain exposure was visible in CS specimens throughout the as-delivered and ground states, the exposure was reduced after polishing. Moreover, while no phase transformation was visible in the LS, phase transformation was visible in CS after every surface treatment, with the M phase content of the CS group showing a significant reduction after polishing (P < .001). CONCLUSION. Within the limits of this study, clinically acceptable level of surface finishing of (Y, Nb)-TZP can be achieved after conventional zirconia polishing sequence.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.4114-4121
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• 2021

The Rooppur Nuclear Power Plant (RNPP), the first nuclear power plant in Bangladesh with a capacity of 2.4 GWe, is under construction on the bank of the river Padma, at Rooppur in Bangladesh. Measurement of background radioactivity in the natural environment adjacent to RNPP finds great importance for future perspectives. Soil and sediment samples collected from upstream and downstream positions of the Padma River (adjacent to RNPP) were collected and analyzed by HPGe gamma-ray spectrometry for primordial radionuclides. The average activity concentrations (in Bqkg^-1) of ²²⁶Ra, ²³²Th and ⁴⁰K radionuclides in soil samples were found to be 44.99 ± 3.89, 66.28 ± 6.55 and 553 ± 82.17 respectively. Respective values in sediment samples were found to be 44.59 ± 4.58, 67.64 ± 7.93, 782 ± 108. Relevant radiation hazard indices and dosimetric parameters were calculated and compared with the world average data recommended by US-EPA. Analytical results show non-negligible radiation hazards to the surrounding populace. Measured data will be useful to monitor any change of background radioactivity in the surrounding environment of RNPP following its operation for the generation of nuclear energy.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제25권6호
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• pp.473-480
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• 2022

Purpose: Low bone mineral density (BMD) is a complication in children with inflammatory bowel disease (IBD). There are limited data evaluating dual-energy x-ray absorptiometry (DXA) as a screening tool for low BMD in children with IBD. We performed a single site retrospective analysis of DXA use. Methods: Children aged 5-18 years with IBD diagnosed between 2013 to 2017 at the Royal Children's Hospital, Australia, were included. Patient demographics, measures of disease activity, DXA scores, and factors related to BMD were collected. Results: Over a median follow up of 5.1 (4-6.4) years, 72/239 (30.1%) children underwent DXA, and 28/239 (11.7%) children had a second DXA. Our DXA practice differed to consensus guidelines regarding initial screening based on height and/or body mass index (BMI) z-score (8/17 [47.1%]), and repeat surveillance (13/42 [31.0%]). Children had a median lumbar spine (LS) z-score -0.80 (-1.65-0.075). Children with LS z-score≤-2.0 (n=14) had lower weight (6.57 [1.78-23.7] vs. 51.1 [26.5-68.7], p=0.0002) and height centiles (3.62 [1.17-17.1] vs. 42 [16.9-67.1], p=0.0001), and higher faecal calprotectin (FCP) (3041 [1182-4192] vs. 585 [139-2419], p=0.009) compared to children with LS z-score>-2.0. No fractures were reported. Of 28 children who underwent a second DXA 1.6 (1.1-2.2) years following initial DXA, no significant change in z-scores occurred. Conclusion: Children with IBD had low BMD. In addition to height centile and weight centile, FCP was associated with lower BMD, and should be considered in DXA screening guidelines. Greater clinician awareness of DXA consensus guidelines is required. Future prospective studies are required.

• Journal of the Korean Wood Science and Technology
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• 제51권1호
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• pp.1-13
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• 2023

Sengon (Falcataria moluccana Miq.) tree offers a wood of low quality and durability owing to its low density and thin cell walls. This study aimed to improve the properties of sengon wood by making the wood magnetic, producing new functions, and characterizing magnetic sengon wood. Each wood sample was treated using one of the following impregnation solutions: Untreated, 7.5% nano magnetite-furfuryl alcohol (Fe₃O₄-FA), 10% nano Fe₃O₄-FA, and 12.5% nano Fe₃O₄-FA. The impregnation process began with vacuum treatment at 0.5 bar for 2 h, followed by applying a pressure of 1 bar for 2 h. The samples were then tested for dimensional stability and density and characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) analysis, and vibrating sample magnetometry (VSM) analysis. The results showed that the Fe₃O₄-FA impregnation treatment considerable affected the dimensional stability, measured in terms of weight percent gain, anti-swelling efficiency, water uptake, and bulking effect, as well as the density of sengon wood. Changes in wood morphology were detected by the presence of Fe deposits in the cell walls and cell cavities of the wood using SEM-EDX analysis. XRD and FTIR analyses showed the appearance of magnetite peaks in the diffractogram and Fe-O functional groups. Based on the VSM analysis, treated sengon wood is classified as a superparamagnetic material with soft magnetic properties. Overall, 10% Fe₃O₄-FA treatment led to the highest increase in dimensional stability and density of sengon wood.

• 대한약침학회지
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• 제25권4호
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• pp.382-389
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• 2022

Objectives: The Korean Industrial Standard (KS) for sterile acupuncture needles was established in 2009 based on research on the quality control of acupuncture needles. We aimed to determine the quality of acupuncture needles available in South Korea in 2021 by examining their surface condition and chemical composition using field-emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS). Methods: In South Korea, there are 23 brands of acupuncture needles, and we examined 10-15 needles from each brand, resulting in a total of 285 needles. The microstructures of the needles were assessed by SEM. Using SEM images, we evaluated the acupuncture needle tips for the following defects/aspects: scratches, lumps, detached coating, bent tip, and tip sharpness. EDS was used to determine the chemical composition of the selected acupuncture needles. Results: Overall, 88.4% of 285 needles were found to have at least one type of abnormality. The most frequently observed abnormalities were scratches and dents on the surface (68.1%), followed by detached coating (63.2%), and lumps (61.8%); blunt tips were observed in about 24% of them. Of 252 needles with at least one defect, 86.9% had two or more types of defects. The ratio of the number of needles with any defect to that of needles without any defect varied among brands, ranging from 50% to 100%. Regarding foreign materials, higher proportions of Si and O were observed on the needles, indicating incomplete or detached silicone coating. Conclusion: The quality of acupuncture needles varied among brands, suggesting that further improvements can be made through various inspection methods.

• 천문학회보
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• 제44권2호
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• pp.41.3-41.3
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• 2019

To find out the origin and formation mechanism of LASCO-C2 post-CME blobs, we investigate 2 LASCO-C2 blobs and 35 low corona blobs observed by K-Cor on 2017 September 10 from 17:11 to 18:58 UT. By visual inspection of a post-CME ray and the locations of low corona blobs in K-Cor and LASCO-C2 images with examining the time-height data of all blobs, we find the following results: (1) The post-CME ray structure is well identified in the K-Cor images than LASCO-C2 ones. (2) Low corona blobs can be classified into two groups according to their formation mechanisms: 27 blobs belong to Group 1, generated by the tearing mode instability near the middles of current sheets as described by Furth et al., 1963; Shibata & Tanuma, 2001; Shen et al., 2011, the others belong to Group 2, formed by the tearing mode instability near the tips of current sheets as shown in Figure 5 of Sitnov et al., 2002. (3) Group 1 has low initial appearance heights <1.30 Rs>, broad speed range (38 ~ 945 km/s), and high accelerations <4,272 m/s² > than Group 2, which has initial appearance heights <1.72 Rs>, speed range (579 ~ 843 km/s), and accelerations <1,413 m/s² >. (4) among 8 blobs for Group 2, only 2 blobs are temporally and spatially associated with 2 LASCO-C2 ones and their initial observation heights are 1.93 and 1.79 Rs, respectively. Our results firstly demonstrate that LASCO-C2 blobs form the heights from about 1.7 to 2.0 Rs and they are generated by the tearing mode instability near the tips of current sheets.

• 한국표면공학회지
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• 제56권6호
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• pp.437-442
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• 2023

This research aims to enhance the efficiency of Pt/C catalysts due to the limited availability and high cost of platinum in contemporary fuel cell catalysts. Nano-sized platinum particles were distributed onto a carbon-based support via the polyol process, utilizing the metal precursor H₂PtCl₆·6H₂O. Key parameters such as pH, temperature, and RPM were carefully regulated. The findings revealed variations in the particle size, distribution, and dispersion of nano-sized Pt particles, influenced by temperature and pH. Following sodium hydroxide treatment, heat treatment procedures were systematically executed at diverse temperatures, specifically 120, 140, and 160 ℃. Notably, the thermal treatment at 140 ℃ facilitated the production of Pt/C catalysts characterized by the smallest platinum particle size, measuring at 1.49 nm. Comparative evaluations between the commercially available Pt/C catalysts and those synthesized in this study were meticulously conducted through cyclic voltammetry, X-ray diffraction (XRD), and field-emission scanning electron microscopy-energy dispersive X-ray spectroscopy (FE-SEM EDS) methodologies. The catalyst synthesized at 160 ℃ demonstrated superior electrochemical performance; however, it is imperative to underscore the necessity for further optimization studies to refine its efficacy.

• Journal of Chest Surgery
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• 제43권2호
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• pp.228-231
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• 2010

3년 전 두피에 발생한 혈관 육종의 과거력이 있는 80세 남자 환자가 호흡 곤란을 주소로 본원 응급실 내원하여 시행한 흉부 X-ray상 좌측 기흉이 진단되었다. 환자는 3년 전 혈관 육종으로 두피의 종양 절제와 방사선 치료를 받았다. 입원 후 지속되는 공기 누출로 폐쐐기 절제술을 시행 받았으며 병리 검사상 혈관 육종의 폐전이가 진단되었다. 환자는 방사선 치료를 시행하였으나 혈관 육종의 폐전이 악화로 폐절제술 후 15개월에 사망하였다. 혈관 육종은 노인에서 두피 또는 얼굴에 호발하는 악성도가 높은 종양으로 드물게 폐에 공동성 병변의 형태로 전이되어 기흉을 발생시킨다. 저자들은 두피에 발생한 혈관 육종의 과거력이 있는 환자에서 폐전이에 의한 기흉을 경험하였기에 보고하는 바이다.

• 멤브레인
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• 제25권2호
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• pp.115-122
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• 2015

졸겔법에 의해서 trimethylborate (TMB)/tetraethylorthosilicate (TEOS) 몰비 0.01, 온도 $800^{\circ}C$에서 $SiO_2{\cdot}B_2O_3$가 제조되었다. 그리고 제조된 $SiO_2{\cdot}B_2O_3$와 PDMS[poly(dimethylsiloxane)]로부터 PDMS-$SiO_2{\cdot}B_2O_3$ 복합막을 제조하고 막의 물리화학적 특성을 TG-DTA, FT-IR, BET, X-ray, SEM에 의해 조사하고 그리고 $H_2$와 $N_2$의 투과도와 선택도를 조사하였다. TG-DTA, BET, X-ray, FT-IR 측정에 의하면 $SiO_2{\cdot}B_2O_3$는 무정형의 다공성 $SiO_2{\cdot}B_2O_3$였으며, 기공의 평균직경은 $37.7821{\AA}$, 표면적은 $247.6868m^2/g$이었다. TGA 측정에 의하면 PDMS 내에 $SiO_2{\cdot}B_2O_3$가 첨가되었을 때 PDMS-$SiO_2{\cdot}B_2O_3$ 복합막의 열적 안정성은 향상되었다. SEM 관찰에 의하면 $SiO_2{\cdot}B_2O_3$는 약 $1{\mu}m$ 크기로 PDMS 내에 덩어리 상태로 뭉쳐서 분산되어 있었다. 기체투과실험에 의하면 PDMS 내에 $SiO_2{\cdot}B_2O_3$ 함량이 증가하면 $H_2$와 $N_2$의 투과도는 증가하였고, 질소보다 Lenard Jones 분자지름이 작은 $H_2$의 투과도는 $N_2$의 투과도보다 컸으며, 선택도($H_2/N_2$)는 감소하였다.