• 열처리공학회지
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• 제7권4호
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• pp.318-327
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• 1994

According to conventional nitriding of tool steels, it was very difficult to produce a high surface hardness. This study has been conducted to investigate the influence of initial structures on the nitriding characteristics of tool steels in gas-nitrided for the improvement in surface hardness. The specimens (SACM645, STD61 steels) have been quenching and tempering at various temperature and then gas-nitrided for 30, 45 and 60hr at 500, 530 and $550^{\circ}C$ respectively in gasatmosphere of 30%$NH_3-70%N_2$ As hardness of initial structure was higher, the nitriding layer was deeper and hardness of the nitriding layer was higher. Deeper nitriding layers was due to higher diffusion rate by fine initial microstructure. Also the reason of high surface hardness was associated with formation of dispersed fine carbonitrides of nitrides.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.409-412
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• 2000

Much research efforts have been made on the structure and properties of metals deformed to severe plastic deformation (SPD). Being deformed to SPD, ultra-fine grains (UFG) are usually formed, and UFG structure exhibits fundamental differences in original physical properties. One method often used to obtain SPD is equal channel angular pressing (ECAP). In order for this technique to be exploited, it is important to understand the deformation behavior during the ECAP processing with respect to friction. The finite element method (FEM) has been used to investigate this issue.

• Asian-Australasian Journal of Animal Sciences
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• 제15권7호
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• pp.1018-1021
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• 2002

The objective of this study was to investigate the villus distribution in the caeca of domestic geese based on the fine structure. The caeca of White Roman geese, 14-week old, were sampled and specimens were detected under photomicroscope and scanning electron microscope (SEM). The results indicated that the villi existed at the proximal caecum. The morphologies of these villi showed finger-like, peak-like or tongue-like shapes. The heights of the villi decreased far from the proximal caecum. No villi were found in the middle and distal caecum. It was obvious that the proximal segment was the main portion for absorbing food nutrients in the caeca. The caecal content particles were small and possessed a viscid character. The large particles filtered out at the proximal caecum just like a mesh. The surface of the middle caecum exhibited parallel ridges with no villi. There were band plicae circular shapes found in the middle caecum under scanning electron microsopy.

• Applied Microscopy
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• 제19권2호
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• pp.1-16
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• 1989

To investigate the research of the tumor seeker using liposomes with negatively stained. The fine structure and size in liposomes composed of PC, DSPC, DAPC and SM phospholipid were observed. And the yield of vesicle affected with sonication by mechanical force were determined. The results were as follows. 1. The stain of 2% UA are obtained a good resolution from electron microscopic observation to compare the negatively liposomes with PTA, AM and UA solution. 2. The fine structure of liposomes except DAPC, PC and CH alone samples could be observed from EM experiment of liposomes composed of PC, DSPC, DAPC and SM phospholipid. 3. The results of experiment from 10, 20, 40 and 60 times sonication with 30sec, prepared 0.1mM NTA-SM-liposomes were obtained unilamella vesicles from groups of multilamella vesicles of phospholipid. 4. About 50nm diameter liposomes obtained through membration filtration step to prepare homogenized liposomes.

• 한국의류학회지
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• 제12권2호
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• pp.181-188
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• 1988

Cotton fabrics were slack-mercerized in sodium hydroxide, ammonia water(min. $28{\%}\;NH_3$), and mixture of ammonia water/sodium hydroxide. The surface of treated cotton fabrics were observed through SEM, and the changes of fine structure were analyzed by X-ray diffractometer. In addition to that shrinkage was compared mutally, and tenacity-elongation compared, too. SEM photographs showed fibrls rearranged strightly toward fibre axis. X-ray diffraction represented increased amorphous fraction, and partial recrystallization into cellulose 2 lattic after treatment with sodium hydroxide and mixture of ammonia water/sodium hydroxide. The mercerization produced increased fibre tenacity-elongation with slark state. Lastly, the best condition of mercerization was $4\%/14\%$, $10^{\circ}C,\;5\~30$ min. in mixture of ammonia/sodium hydroxide.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1045-1047
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• 2006

Fabrication of $Mg_{95.75}Zn_1Y_3Yb_{0.25}$ bulk alloy has been performed through the consolidation of rapidly solidified ribbons. The $Mg_{95.75}Zn_1Y_3Yb_{0.25}$ bulk alloy exhibited excellent mechanical properties, high tensile yield strength of 530 MPa, and large elongation of 3 %. Microstructure of the alloy was characterized by equiaxed fine grains that consist of -Mg, long period ordered (LPO) structure phase, and $Mg_5RE$-type cubic compound. The strengthening of the alloys may be due to fine grains with LPO structure phase and $Mg_5RE$-type compound.

• 천문학회지
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• 제23권1호
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• pp.31-42
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• 1990

Fine structures of a quiescent prominence are studied by analyzing high resolution H alpha filtergrams and H alpha line spectra observed at the Hida Observatory of Kyoto University. We have found two kinds of downward motions in the prominence. One of them is a movement with a constant acceleration below the solar gravity(${\simeq}1/4g_s$) and the other with an uniform velocity(${\simeq}16Km/s$). The average life time and the size of prominence knots are estimated to be about 7 minutes and 4000Km, respectively. Spatial and brightness distribution of knots are also presented in this paper. With the analytical solutions derived from magnetostatic equilibrium in the prominence, we have examined the filamentary structure based on the Kippenhahn-Schluter model. Sag angles of the magnetic fields supporting the prominence matter are predicted from the observed density profile.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1998년도 한국생물과학협회 학술발표대회
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• pp.128.1-128
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• 1998

No Abstract, See Full Text

• 복합신소재구조학회지
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• 제6권1호
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• pp.37-42
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• 2015

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2006년도 한국우주과학회보 제15권2호
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• pp.80-80
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• 2006