• 대한세포병리학회지
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• 제16권2호
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• pp.93-97
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• 2005

Merkel cell carcinoma (MCC) is a rare primary cutaneous neuroendocrine carcinoma which commonly presents as a skin nodule, and can develop into regional lymph node metastases, as well as spread systematically. Here, we describe the cytological features of a touch imprint of MCC that arose on the face of a 62-year-old female. This touch imprint was acquired from an incisional biopsy specimen which had been submitted for frozen section. The touch preparation produced a highly cellular imprint of loosely cohesive groups of small- to medium-sized malignant cells exhibiting uniform round to oval nuclei, delicate nuclear membranes, fine chromatin, small nucleoli, and scanty cytoplasm, with occasional paranuclear button-like inclusions. We applied cytokeratin 20 to the touch imprint for immunochemistry, allowing us to visualize the tumor cells with paranuclear dot-like positivity. Both the cytological and immunocytological features were quite distinct.

• Journal of Welding and Joining
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• 제17권1호
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• pp.82-87
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• 1999

The basic remote sleeve repair-welding technology by the pulsed Nd:YAG laser for increasing the lifetime of the steam generator tube in a nuclear power plant has been developed. The relationship between the connection width and welding parameters have been investigated for the fundamental research to apply the sleeve-repair-welding technique to the nuclear industry. The Inconel 600 tube and Inconel 690 sleeve used for high temperature and high pressure service were welded as round lap welding by Nd:YAG laser. It was observed that the tensile shear strength, 340MPa of the welded specimen is equivalent to about 60% of that of the base metal (Inconel 600), 550MPa. The difference between the hardness of the base metal and that of the laser welds was about 10%. Ductile fracture was partly occurred in the weld but the cracking has not been observed. In spite of absence of the crack, the strength of welds was not sufficient in terms of the tensile shear strength.

• Restorative Dentistry and Endodontics
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• 제24권4호
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• pp.554-559
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• 1999

Aucubin, an iridoid glucoside isolated from Aucuba japonica, has pharmacological effects such as antimicrobial effect, liver protective function and inhibition of liver RNA and protein biosynthesis, etc. This study was performed to observe the effect of aucubin on the pulp tissue after pulpotomy. Aucubin was converted to aucubinogenin as an active form by ${\beta}$-glucosidase. In 3 Mongrel dogs, the pulps were mechanically exposed with a sterile round bur and excised with sterile excavator. After bleeding control, aucubin was applied on remaining pulp tissues and then they were sealed with IRM in experimental group. In control group, $Ca(OH)_2$ powder was applied on remaining pulp tissues and then they were sealed with IRM. After interval of 1 and 12 weeks, the dogs were sacrificed. The teeth were prepared for histologic evaluation and examined by light microscope. Aucubin 1 week group showed that mild inflammation and vascular congestion in most of the specimen. More various degree of inflammation was found in experimental group than in control group. Premature calcified mass were found in the both 1 weeks groups. Continuous well-formed dentin bridge was found in both 12 weeks groups. Collectively, this study suggests that the possibility of aucubin as a medicament after pulpotomy.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.176-180
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• 2001

In this paper, we have studies the images have been reconstructed by using combination of images which has been acquired by the variation of operating frequency. When inner images has been reconstructed, inner image has been superposition by surface state effect. In this case, image enhancement the phase object and enhance the contrast of inner image. In the result of the specimen for the round defect with 2mm diameter, for the types of the depth are 1.5mm, 2mm, 2.5mm, and 3mm, it has been show that the shape of defect has better than before this processing and phase contrast grow large twice. And we have constructed the acoustic microscope by using quadrature detector that is able simultaneously to acquired the amplitude and phase of the reflected signal. Father more we have studied the reconstruction method of the amplitude and phase images and the enhancement method of the defect images' contrast.

• Journal of Welding and Joining
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• 제23권6호
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• pp.87-92
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• 2005

It has been well hewn that ductile fracture of steels is accelerated by triaxial stresses. The characteristics of ductile crack initiation in steels are evaluated quantitatively using a two-parameters criterion based on equivalent plastic strain and stress triaxiality. The present study focuses on the effects of strength mismatch, which can elevate plastic constraint due to heterogeneous plastic straining, on the critical condition for ductile fracture initiation usinga two-parameter criterion. Fracture initiation testing has been conducted under static loading using notched round bar specimens which had different notch locations. This study provides the fundamental clarification of the effect of strength mismatching and effect of notch location on the critical condition to ductile crack initiation from notch root using fuite element method and ultrasonic-mechatronics system. The critical condition of ductile crack initiation from notch root of strength mismatched tensile specimens under static loading appeared to be almost the same as those of homogeneous tensile specimens with circumferential sharp notch specimen. Also, the effect of notch location in mismatched specimens was estimated using finite element(FE) analyses.

• Parasites, Hosts and Diseases
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• 제46권3호
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• pp.165-169
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• 2008

Microphallus species occur primarily as intestinal parasites of birds and mammals, and metacercariae of a new species belonging to this genus have been discovered from the crab, Macrophthalmus dilatatus, in the Republic of Korea. The metacercaria of this fluke was round with 2 thick walls, and the excysted one had mature genital organs. The adult flukes recovered from experimentally infected chicks had numerous intrauterine eggs, well-developed pars prostatica, widely bifurcating ceca, and prominent uterine bulge. After observing internal structures, it was concluded that this species is different from any other known Microphallus spp. Based on the morphology of metacercariae and adult flukes, we describe this specimen as a new species, Microphallus koreana n. sp.

• 한국기계가공학회지
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• 제20권1호
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• pp.57-65
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• 2021

With the increased utilization of CAM programs, end-mill processing is most commonly used for machining and metal processing. In particular, hole or shaft machining has high assembly precision, which inevitably leads to high utilization of end mills. However, the analysis of quality characteristics according to the process conditions of end mills is not performed systematically at the site, causing poor quality and productivity. The most influential factor of quality is the runout of the end mill. In this paper, the number of turns of the end mill, number of tool blades, cutting direction, and artificial runout volume were determined to identify the correlation between the epicenter, cylindricality, and surface roughness. Two types of end mills, three levels of runout, three levels of rotational speed, and two cutting directions were considered and 36 rounds of hole processing were conducted. For the analysis of shape characteristics according to the set process variables, the experimental planning method was applied to the measured specimen and the processing characteristics were analyzed according to the runout of the end mill through correlation analysis.

• 한국어류학회지
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• 제34권1호
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• pp.1-7
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• 2022

북서태평양 표층에서 채집한 후기 자어 (2.2 mm BL)의 미토콘드리아 전장 유전체를 근거로 Himantolophus groenlandicus로 동정하였다. 후기 자어는 둥근 몸통, 작은 이빨, 발달하기 시작한 등 지느러미, 아래 부분이 들어간 눈, 그리고 지느러미, 정수리, 등 부분에 분포하는 흑색소포를 가졌다. 이러한 특징은 크기가 유사한 동종으로 보고된 자어(2.1 mm BL)와 차이가 컸다. 본 연구 자어의 유전적, 형태적 특징은 유사종의 동정에 유용할 것이다.

• Elastomers and Composites
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• 제48권2호
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• pp.172-179
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• 2013

고분자 소재의 충격강도 증대를 위해 충격보강제를 이용하는 경우가 많다. 본 연구에서는 충격보강제가 함유된 나일론6에 대해서 충격보강 원리를 분석하고자 충격시험을 모사하였다. 이를 위해 나일론6에 포함된 충격보강제인 고무 첨가제의 모델링을 시도하였다. 모델링을 토대로 충격시험을 모사하고 충격시편 단면에서의 응력 분포 및 방향을 통해 충격강도 증대 원리를 관찰하였다. 시편 단면에서 충격보강제 유무에 따른 해석을 하여 비교하였고, 충격보강을 위해 사용되는 고무첨가제의 표면처리 여부에 따른 해석도 수행하여 응력을 비교하였다. 해석결과 노치에서 발생한 응력이 내부로 전파되면서 충격보강제 주변으로 경로가 바뀌면서 응력이 감소되는 현상이 나타났다. 특히 충격보강제를 함유한 시편에서 노치부 표면의 응력이 낮았다. 또한, 크랙이 발생하는 방향과 직각인 방향의 주 응력 크기도 충격보강제를 포함한 시편에서 낮게 나타났다. 이로 인해 크랙의 전파가 감소되고 충격강도가 증대되었다고 분석된다. 이러한 컴퓨터모사 방법은 복합재료의 물성 증대 원인을 파악하는데 활용할 수 있다고 판단된다.

• 비파괴검사학회지
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• 제25권4호
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• pp.294-303
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• 2005

본 논문은 가압 중수로형 원자력발전소 압력관의 건전성 평가에 적용하고 있는 각 비파괴검사기술의 특정을 평가하기 위해서 IAEA(International Atomic Energy Agency)주관으로 세계 6개국이 참여하는 수행한 다자간 비교시험(Round-Robin Test)결과를 분석한 내용이다. 이 다자비교시험에는 세계적으로 현재 가압 중수로형 원자력발전소를 운영하고 있는 한국, 카나다, 인도, 아르헨티나, 루마니아, 중국 등 총 6개구깅 참여하였으며, 시험에는 한국에서 제작한 인공결함시험편(시험편명 : "KOR-1")이 사용되었다. 본 연구를 위해 참여 6개국에서 적용한 비파괴검사 기술은 현재 압력관의 건전성 평가에 적용되고 있는 초음파검사와 와전류검사 등의 2가지 기술이다. 결함시험편에는 균열성 노치, 마모 등의 총 12개의 인공결함이 포함되어 있으며, 이 인공결함은 발전소 운전중 발생 가능성이 있는 결함과 유사한 형태를 가지고 있다. 다자비교시험 결과 참여 6개국에서 두가지 비파괴검사법을 적용하여 시험편내에 포함되어 있는 총 12개의 모든 인공결함을 검출하였으며, 결함 검출도는 초음파검사법이 와전류검사법보다 우수하였다. 또한 압력관 시험편 내경측 결함이 외경측 결함보다 용이하게 검출되었으며, 크기 측정 정확도는 결함 검출도와 동일하게 시험편 내경측 결함의 크기가 외경측 결함보다 더 정확하게 측정되었다.