• 소성∙가공
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• 제19권8호
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• pp.480-485
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• 2010

In this work, the closing behavior of cylindrical-shaped voids was experimentally investigated according to various parameters such as reduction ratio in height, initial void size and billet rotation during hot open die forging process. The reduction ratio in height, number of path, and billet rotation were chosen as key process parameters which influence the void closing behavior including the change of void shape and size. On the other hand, values of die overlapping and die width ratio were set to be constant. Void closing behavior was estimated by microscopic observation. Based on the observations, it was confirmed that application of billet rotation is more efficient to eliminate the void with less reduction ratio in height. The experimental results obtained from this study could be helpful to establish the optimum path schedule of open die forging process.

• 한국정밀공학회지
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• 제17권2호
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• pp.169-175
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• 2000

The object of this study was to investigate the feasibility of solid-phase forming of the composites and to characterize the material behavior in the biaxial stretch forming. The materials tested contained 20%, 30%, and 40% glass fibers by weight in a polypropylene matrix. Biaxial stretch forming tests were performed at three forming speeds of 10mm/sec, 1mm/sec, and 0.1mm/sec and at four forming temperatures of $75^{\circ}C, 100^{\circ}C, 125^{\circ}C, and 150^{\circ}C$ to investigate effects of forming speed and forming temperature. The microscopic observation of a formed part was conducted at various strain levels to characterize the material behavior. The strain distribution on a formed part was measured and displayed on the farmed geometry with a contour display The material behavior of the composite in the biaxial stretch forming was strongly influenced by the forming conditions.

• 한국잠사곤충학회지
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• 제7권
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• pp.81-87
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• 1967

우리나라 생사의 재조절단에 관해 원인별로 분석 고찰한 결과 다음과 같다. 1. 우리나라 생사의 절단비율은 절단종류 10 여종 중 다친실(상사)43.23%, 고착(고착) 16.07％, 갈린실(열사) 11.70％ 및 엉킨실 7.22％ 등이 그 대부분이었다. 2. 춘추별로 절단비율에 차가 있음을 발견하였다. 3. 원인별로 절단부위의 현미경관찰을 하고 그 발생원인을 고찰하였으며 그 방지책을 강구하였다.

• 한국환경성돌연변이발암원학회지
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• 제22권4호
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• pp.255-258
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• 2002

In order to determine the safety of chemicals and pharmaceutical products, various methods can be used to evaluate the toxicity. In this study the genotoxic effect of the widely used industrial chemical, cadmium chloride, was assessed using the micronucleus test in peripheral blood of mice. The presence of micronucleated reticulocytes by microscopic observation following acridine orange staining indicated a potential genotoxic effect. The genotoxicity of intraperitoneally (i.p.) administered cadmium chloride (0.5, 1, 2 mg/kg) appeared to be dose dependent, with the maximum tolerated dose (MTD) found to be 2 mg/kg. Compared to the negative control (saline), cadmium chloride (2 mg/kg) exhibited statistically significant genotoxic potential (P<0.05) but was found to be less than the positive control of mitomycin C (0.5 mg/kg) and was not statistically significant compared to historical negative controls (P>0.05).

• 환경위생공학
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• 제22권3호
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• pp.27-33
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• 2007

M. incognita are plant-parasite nematode that cause severe damage to the crops. P. lilacinus are renowned for inhibitation of development of M. incognita's egg. We make a study for enzymatic examining the cause closely that P. lilacinus suppress development of M. incognita's egg by parasiting. The research result is explained the place below. 1. The egg that is exposed to co-enzymes which are cultured in the broth culture starts to change the membrane of egg from 3days. And in 10days, that membrane completely disappear. These are observed through light microscope. Therefore, we know that M. incongnita are controlled by extracellular lytic enzymes that are produced by P. lilacinus. 2. Through scanning electron microscope, we can find that the egg that is attacked by P. lilacinus loses it's membrane gradually, and that loss of the membrane causes transform, which suppresses the development of egg.

• 한국잠사곤충학회지
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• 제39권1호
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• pp.30-35
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• 1997

A rapid and sensitive detection of BmNPV contamination in silkworm rearing room was carried by Plymerase chain reaction(PCR). Silkworm nuclear polyhedra were dissolved for the extraction of viral DNA within 30 minutes followed by the treatment of alkaline solution. The combination of primers of NP3 and NP2 was superior in PCR to the other 7 primers applied. Each primer was designed with 20 base in size and Newly designed NP3 of sense and the already reported NP2 for antisense were better in reaction than other primers. PCR products appeared 500bp in size. And annealing was confirmed proper at 55$^{\circ}C$ condition. Amplifiable template DNA amount was confirmed at least 100 ng to 0.1 ng and regarded as applicative for the assay of silkworm rearing environmental condition of sericultural farm. In case of the detection of BmNPV from the dust, sensitivity by PCR was as high as 1,000,000 times than that of microscopic observation.

• Journal of Microbiology and Biotechnology
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• 제21권5호
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• pp.477-482
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• 2011

There are accumulating evidences suggesting that connexin (Cx), a gap junction channel-forming protein, acts as a growth suppressor in various cancer cells, and this effect is attributeed to the gap junction-mediated intercellular communication (GJIC). In order to characterize the relationship between the growth-arresting activity of Cx26 and its cytoplasmic localizations after expression, we linked a nuclear export signal (NES) sequence to Cx26 cDNA before transfecting into a rat breast cancer cell line. A confocal fluorescent microscopic observation revealed that the insertion of NES minimized the nuclear expression of Cx26, and increased its cytoplasmic expression, including plasma membrane junctions. Total cell counting and BrdUrd-labeling experiments showed that the growth of the breast cancer cells was inhibited by 74% upon transfection of Cx26-NES, whereas only 9% inhibition was observed with only Cx26 cDNA.

• 한국임상수의학회지
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• 제16권2호
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• pp.492-496
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• 1999

A 3-year old male Maltese, which had enlarged and ballooned superficial lymph-nodes, was admitted to the Veterinary Teaching Hospital, College of Veterinary Medicine, Kyung-pook National University. Radiographic findings indicated cranial mediastinal mass, interstitial pneumonitis, conspicuous splenomegaly and liver enlargement. The patient showed anorexia, depression and anemia. It was autopsied following its death 2 days after admittance. There were copious hemoperitoneum, lymphomatous mass in the spleen, torsion of the mesenterium and stenosis of the duodenum. On the microscopic observation, there was the increase of the amount of lymphocytic cytoplasm and numbers of nucleus-devided lymphocytes followed by their diffused infiltration in lymph nodule. Based on the physical, histological and pathological findings, this case was diagnosed as a multicentric form of lymphosarcoma.

• 펄프종이기술
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• 제42권2호
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• pp.27-34
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• 2010

To obtain the basic information for the use of bamboo, the anatomical characteristics of moso bamboo shoots, and 20-day-old, 60-day-old, one-year-old, and two-year-old moso bamboo were observed by using polarizing microscope. The cross section showed that the bamboo shoots consists of the early stage of cell formation, atactostele, parenchyma, and bundle sheath was formed in 20-day-old moso bamboo, and all cells completely formed in 60-day-old moso bamboo. The tissues in one-year-old moso bamboo appeared to be completely matured. On the tangential surface, no atactostele was observed in the bamboo shoot, but metaxylem, parenchyma, and bundle sheath were found. atactostele and parenchyma appeared to be formed between 20 and 60 days. All tissues and cells were totally formed and the cell wall of parenchyma were completely matured after one year. The metaxylem in bamboo shoots was observed to have pits, which means that it could be the tissues first formed of all bamboo cells.

• 한국응용곤충학회지
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• 제16권2호
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• pp.121-125
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• 1977

지금까지 우리나라에 발생되지 않았던 새로운 수도 바이러스병인 벼 흑조위축병에 대하여 실시한 확인 및 동정 실험결과는 다음과 같았다. 1) 애멸구(Laodelphax Striatellus FALLEN)가 벼 흑조위축병을 매개하였다. 2) 바이러스의 입자는 구형이었으며 직경은 약60nm이었다. 3) 이 병은 령, 호남지방 및 충청북도에서 발생하였다. 4) 이앙시기가 빠를수록, 바맥일수록 이병주율이 높았다.