• Progress in Superconductivity
• /
• 제1권1호
• /
• pp.20-25
• /
• 1999

We constructed a high-$T_c$ scanning SQUID microscope (SSM) operating in the liquid nitrogen. We used a washer-type YBCO SQUID with inner and outer dimensions of $12{\mu}m$ and $36{\mu}m$, respectively, which was grown on the $SrTiO^3$ bicrystal substrate. The sample, rather than SQUID, was scanned using two stepping motors. We also developed readout electronics, stepping motor controller, and the software for system control and data display. We took images of various samples using our SSM and found that the spatial resolution is about $40{\mu}m$ and noise level is lower than $10^{-7}T/{\surd}Hz$ at 100 Hz and higher at lower frequencies. The noise level was much higher than that of a typical SQUID due to the other coupling from the electric parts. We present a simple argument on the inductive coupling between the sample and the SQUID which should be under-stood for the proper interpretation of the obtained images. By comparing the measured data with the simulation results the gap between the SQUID and the sample is estimated to be $40{\mu}m$.

• Nuclear Engineering and Technology
• /
• 제50권5호
• /
• pp.788-793
• /
• 2018

High-density spent fuel (SF) storage racks have been installed to increase SF pool capacity. In these SF racks, neutron absorber materials were placed between fuel assemblies allowing the storage of fuel assemblies in close proximity to one another. The purpose of the neutron absorber materials is to preclude neutronic coupling between adjacent fuel assemblies and to maintain the fuel in a subcritical storage condition. METAMIC neutron absorber has been used in high-density storage racks. But, neutron absorber materials can be subject to severe conditions including long-term exposure to gamma radiation and neutron radiation. Recently, some of them have experienced degradation, such as white spots on the surface. Under these conditions, the material must continue to serve its intended function of absorbing neutrons. For the first time in Korea, this article uses a neutron attenuation test to examine the performance of METAMIC surveillance coupons. Also, scanning electron microscope analysis was carried out to verify the white spots that were detected on the surface of METAMIC. In the neutron attenuation test, there was no significant sign of boron loss in most of the METAMIC coupons, but the coupon with white spots had relatively less B-10 content than the others. In the scanning electron microscope analysis, corrosion material was detected in all METAMIC coupons. Especially, it was confirmed that the coupon with white spots contains much more corrosion material than the others.

• 한국정밀공학회지
• /
• 제26권11호
• /
• pp.92-98
• /
• 2009

The scanning electron microscope (SEM) contains an electron optical system in which electrons are emitted and moved to form a focused beam, and generates secondary electrons from the specimen surfaces, eventually making an image. The electron optical system usually contains two condenser lenses and an objective lens. The condenser lenses generate a magnetic field that forces the electron beams to form crossovers at desired locations. The objective lens then focuses the electron beams on the specimen. The present study covers the design and analysis of an objective lens for a thermionic SEM. A finite element (FE) analysis for the objective lens is performed to analyze its magnetic characteristics for various lens designs. Relevant beam trajectories are also investigated by tracing the ray path of the electron beams under the magnetic fields inside the objective lens.

• Applied Microscopy
• /
• 제25권4호
• /
• pp.9-16
• /
• 1995

Ultrastructure of stemmata(larval eye) of 5th-instar larval in cabbage butterfly, Pieris rapae L, was morphologically investigated with light microscope, scanning electron microscope and transmission electron microscope Six stemmata are on each side of the head. Stemmata V and VI have a Y-shaped sulcus on the surface of their corneal lenses, the others have a columnar shaped process and smooth globular surface. The visual type of stemmata is resembled a single ommatidium of compound eye. The dioptric apparatus are a biconvex shaped cornea and crystalline cone. As a photoreceptor, each stemmata consists of 7 retinular cells arranged into 2 tiers. The first ceil tier of 3 distal retinular cells has formed a V-shaped cup rhabdome and the second cell tier of 4 basal retinular cells has formed a H-shaped fused rhabdome. Each retinular cell filled with pigment granules and contained multivesiclular bodies, coated vesicle and common organelles. The peripheral parts of retinular cells are enveloped by neuroglia cells and retinular cells are surrounded by 3 corneagenous cells. The distal portions of the 3 corneagenous cells contact each other, but the Y-shaped stemmata is separated from each other immediately under the cornea. The 7 axons from each stemma congregate into a bundle and each 7-axon group joins to form a stemmatal nerve, consisting of 42 retinular axons.

• 한국안광학회지
• /
• 제10권2호
• /
• pp.119-126
• /
• 2005

2개사 칼라콘택트렌즈에 대한 물성적 특성을 평가 비교하였다. 제조된 인공누액을 사용하여 단백질 침착율과 습윤성, 주사전자현미경과 원자간력현미경을 이용하여 렌즈의 표면 거칠기를 관찰하였다. 결과는 다른 특성들은 일반 소프트콘택트렌즈와 비교해서 큰 차이를 보이지 않았으나 주사전자현미경적 관찰에서 건조시 심한 균열을 보였다. 원자간력현미경적 관찰에서 렌즈 표면요철은 발견되지 않아 표면거칠기는 일반 소프트콘택트렌즈와 차이가 없었다. 렌즈 앞면과 뒷면에 대한 염료 침착을 확인한 결과 염료는 렌즈내부에 존재함을 알 수 있었다.

• 한국재료학회지
• /
• 제16권8호
• /
• pp.511-515
• /
• 2006

The dispersion hardened $Cu-TiB_2$ composites are a promising candidate for applications as electrical contact materials. The $Cu-TiB_2$ composites for electrical contact materials can reduce material cost and resource consumption caused by wear, due to their good mechanical and electrical properties. In this study, we investigated the wear phenomenon for $Cu-TiB_2$ composites fabricated with hot extrusion, by varying particle sizes and volume fractions of $TiB_2$. The wear tests were performed under the dry sliding condition with a fixed total sliding distance of 40 m. The contact loads at a constant speed of 3.5 Hz were 20, 40, 60, and 80 N. The friction coefficients and wear losses were measured during wear tests. Worn surfaces and wear debris after wear tests were investigated using the scanning electron microscope and the optical microscope. The microstructures of interface between Cu matrix and $TiB_2$ particle before and after wear tests were studied by the transmission electron microscope.

• Archives of Reconstructive Microsurgery
• /
• 제21권2호
• /
• pp.149-152
• /
• 2012

Purpose: The vessels of peripheral nerves have been extensively studied since Breidenbach used vascularizd nerve grafts. Tayor and Pinel studied the course and distribution of the vessels of peripheral nerves. However, the vessels of digital nerves are still not well known. The objective of this study was to prove vessels of digital nerves and to investigate the pathway of that. Materials and Methods: 36 patients and 2 fresh human cadavers were studied under the microscope and histologic sections under the light microscope.. Results: We found that digital nerves had own arterioles and venules as well as peripheral nerves. This small vessels of digital nerves paralleled the digital nerves or run in a spiral. Digital nerves were abundantly vascularized throught their length by a succession of vessels and by their repeated divisions and anastomoses. Conclusion: The clinical implications of this results can be discussed in relation to the dissection of nerves, the possibility of vasculized nerve grafts.

• 시스템엔지니어링학술지
• /
• 제15권2호
• /
• pp.72-78
• /
• 2019

Pathology is the motor that drives healthcare to understand diseases. The way pathologists diagnose diseases, which involves manual observation of images under a microscope has been used for the last 150 years, it's time to change. This paper is specifically based on tumor detection using deep learning techniques. Pathologist examine the specimen slides from the specific portion of body (e-g liver, breast, prostate region) and then examine it under the microscope to identify the effected cells among all the normal cells. This process is time consuming and not sufficiently accurate. So, there is a need of a system that can detect tumor automatically in less time. Solution to this problem is computational pathology: an approach to examine tissue data obtained through whole slide imaging using modern image analysis algorithms and to analyze clinically relevant information from these data. Artificial Intelligence models like machine learning and deep learning are used at the molecular levels to generate diagnostic inferences and predictions; and presents this clinically actionable knowledge to pathologist through dynamic and integrated reports. Which enables physicians, laboratory personnel, and other health care system to make the best possible medical decisions. I will discuss the techniques for the automated tumor detection system within the new discipline of computational pathology, which will be useful for the future practice of pathology and, more broadly, medical practice in general.

• 건축역사연구
• /
• 제22권6호
• /
• pp.59-66
• /
• 2013

This study progressed an investigation on the cause of the efflorescence phenomenon of bricks in Suwon Hwaseong Fortress, which is designated as a UNESCO World Heritage by using diverse scientific analyses. The samples were taken in Hwaseong and analyzed using XRD and SEM-EDS for the material identification of efflorescence. We observed under a polarizing microscope and measured absorption factors for the basic investigation for traditional bricks. As a result of material identification, soluble salt($Na_2SO_4$, $KNO_3$) and insoluble salt($CaCO_3$) were detected. There was no big difference between original bricks and repaired bricks under the polarizing microscope. However, in terms of the water absorption rate, bricks which were used for repair nowadays showed low water absorption rate(1%). In conclusion, soluble salt and insoluble salt appeared due to an effect of an air pollution and joint mortar. Soluble salt was removed in the rainy season, but insoluble salt was not removed. As a result of the efficiency and safety tests for chemicals removing efflorescence, chemical E is likely to be the suitable chemicals for the efflorescence phenomenon of traditional bricks in Suwon Hwaseong Fortress. In the future, consideration whether the use of lime is available or not should be studied through comprehensive researches including repair work, construction work and the environment factor with lime. Also, physical, chemical identifications of repairing bricks will be required.

• Journal of Microbiology and Biotechnology
• /
• 제12권5호
• /
• pp.746-752
• /
• 2002

The purpose of the present study was to examine the antagonistic activities of Enterococcus faecalis strain PL9003 (PL9003) on Helicobacter pylori. This strain was isolated from infant feces and found to inhibit both the growth of H. pylori and its in vitro adherence to the human gastric cell line MKN-45. The binding of PL9003 to MKN-45 was observed under a light microscope after Cram staining and under a scanning electron microscope. When detected with an FITC-conjugate antibody, both viable and nonviable PL9003 were found to decrease the number of H. pylori bound to MKN-45. When detected by an enzyme-linked immunoabsorbent assay, about 70% of the H. pylori bound on MKN-45 disappeared with the four-1314 addition of viable or nonviable PL9003. The spent culture supernatant (SCS) of PL9003 also decreased the viability of H pylori even after neutralization and pepsin treatment. The above results suggest that PL9003 has a potential as a new probiotic for the stomach.