• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.281-284
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• 1995

A molecular photodiode was fabricated with hetero-Langmuir-Blodgett (LB) film consisting of an electron accepter(A) and sensitizer. N-Allyl-N-[3-propylamido-N\",N\"-야(n-octadecyl)]-4,4-bipyridum Dibromide and 7,8-dimethyl-10-dodecyl isoalloxan-zine were used as A and S units, respectively. By aligning hefter-LB film of A/S units on ITO glass with an aluminium thin film, a molecular photodiode with the structure of Metal/Insulator/Metal(MIM) was constructed. Due to excitation by irradiation with a 460nm monochromatic light source, the photo-induced unidirectional flow of electrons in the MIM device could be achieved and was detected as photocurrents. The direction of energy flow was in accordance with the energy level profile across the LB films. The photo switching function was achieved and the rectifying characteristics was obserbed in the molecular devise.

• 대한치과의사협회지
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• 제15권4호
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• pp.285-288
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• 1977

The purpose of the current study was to evaluate the effect of the zinc-deficient diet on the connectine tissue of oral mucosa in the albino rats. The zinc dificient diets were supplied to the rats for 4 weeks. The results were as follows: Most of the papillas of lamina prmina propria were shortened. The abnormal distribution and orientation of the fibrous elements were observed. The stain ability of fihrous elements in the Mallory azan stain was decreased. The amorphous intercellular substance showed slight metachromasia in the toluichine blue stain and low PAS reactinity.

• 산업기술연구
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• 제16권
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• pp.257-265
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• 1996

When machining of a free-form surface with a ball endmill it is very important to select proper cutting conditions considering the geometrical shape of a workpiece to make the production more effective and reduce the machining time. Even though the same cutting conditions and materials are used, the cutting system of different geometry part machining shows the different static/dynamic characteristics. In this study, through various cutting experiments, we can construct the data base of stable cutting conditions for the machining of a Zine Alloy. We can get some relational plots between the optimal feedrates and classified shape features and parameters. On the basis of these results, we can develop the feedrate optimization program OptiCode. The developed program make it possible to reduce the cutting time and increase the machining accuracies.

• 한국표면공학회지
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• 제21권4호
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• pp.168-175
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• 1988

The nickel0zinc allot depositions have been studjen in ammonium chloridw added chloride baths to fine out the effects of ultrasonic irradiation for the electrodeposition processes. The compositions of deposited alloys, the current efficiencies, corrosion resistance and brightness in various conditions of electrodeposition were investigated, in the range of ultrasonic irradiation of 50,500 and 1,000kc/s respectively. The results obtained are as follows; 1. the ratio of nikel to zinc in the deposit increased according 시 the ammonium chloride concentration in irradiated baths. 2. The current efficiencies became also higer in the irradiated bath. 3. Ammonium ions in solution seem to retard formation of zinc hydroxide. 4. The corrsion resistance and brightness of the deposits are dependent upon nickel content of deposits which ranges 10-18%(wt)nickel in the irradiated baths and 11-15%(wt)in ninirradisted baths. 5. The corrosion resistance and brightnes of the deposited are appreciably better in the irradiated baths than in non-irradiated bath with the mole ratio of 3.4(NH+4/Ni+++Zn++).

• International Journal of Aeronautical and Space Sciences
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• 제7권1호
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• pp.27-42
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• 2006

A method to design the contour and conception of a plug nozzle of arbitrary shape, but specified exit flow conditions is presented. Severals shapes can be obtained for exit Mach number by changing the specific heats ratio. The characteristics of the nozzle in terms of length, weight and pressure force exerted on the wall are compared to the Minimum Length Nozzle and found to be better. Our field of study is limited to the supersonic mode to not to have the dissociation of the molecules. The design method is based on the use of the Prandtl Meyer function of a perfect gas. The flow is not axial at the throat, which may be advantageous for many propulsion applications. The performance benefits of the plug nozzle compared to the Minimum Length Nozzle are also presented.

• 한국표면공학회지
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• 제18권2호
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• pp.53-60
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• 1985

The microstructure of zine electrodeposits was investigated by using zinc sulfate solution in still bath. The cathode current efficiency decreased with increasing current density, and decreasing temperature. The preferred orientation of the zinc electrodeposits changed from (10.3) texture to(10.${\ell}$)-(00.1)(${\ell}$=1, 2, 3) texture through (10.2)-(10.3) preferred orientation with increasing cathode over potential. The surface morphology of zinc electrodeposits changed from the dendritic growth with granular crystallites to the blocks of hexagonal crystallites packed together with increasing current density. The microstructure of cross section of the above deposits are the rough granular structure and columnar structure respectively.

• 한국표면공학회지
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• 제22권1호
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• pp.17-25
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• 1989

The structural Charactesties and adhesion of chemically vapor deposited TiN film on stain less steels have been investated as functions of deposition temperature, surface roughness of sub state, and types of substrates. The grain zine and the lattice parameter of TiN film decreased with decreasing roughness of substates. The(200) preferred orientation was developed dominatly and the lattlice parameter decreased as temperature intereased reardless of the surdless roughnessand type of the substrates used. The surface morphology of TiN film changed from bushed crystal to a plate and then to pyamidal dense crystals with an increase in the deposition temperature. The adhesion of TiN films increased with coating thinkness and decreased with surface roughness in general. The calculations using a Bejamin & Weaver's model have been compard. Maximum valuse of adhesion energy calculated using Laguier's model were W304=331Jm-2,w410=113Jm-2,andW430=107jm-2

• Archives of Pharmacal Research
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• 제17권6호
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• pp.411-414
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• 1994

Phenylazocyanothioacetamide 1 reacts with malononitrile to afford the pyridinethione 4 which reacts with phenacylbromide to yield the pyridine-S-phenacyl derivative 6, 1 reacts with ethyl cyanoacetate to yield the pyridazine derivative, 8, and with phenacyl bromide to afford the N-phenacyl derivative 11, instead of the thiazole 10. Compound 11 afforded the pyrazolopyridine 13 on reaction with malononitrile while 10 was obtained on coupling of the thiazole 14 with diazotised aniline. Compound 10 reacts with malononitrile to afford the thizaolyl pyridazine 15. Compound 1 reacts with malononitrile dimer to afford the pyriodopyridazine derivative 17a. 1 reacts also with active methylene heterocycies to afford the pyrazolo and thiazolo-fused phridazines 20 and 23 respectively.

• 한국전기전자재료학회논문지
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• 제11권10호
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• pp.842-848
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• 1998

The stability of paraseodymium-based zinc oxide varistor consisting of Zn-Pr-Co-Cr-Y oxide was investigated according to yttria additives under different stress conditons, such as 0.8V\ulcorner\ulcorner/373K/12h and 0.85V\ulcorner\ulcorner/393K/12h. Wholly, all varistor after the stress showed nearly symmetric and stable I-V characteristics. Particularly, in the case of 2.0mol% and 4.0mol% yttria-added varistor showing a good I-V characteristics, the varation rate of varistor voltage were less 1% and that of nonlinear coefficient were about degree of 5%, and what is remarkable, leakage current with increasing stress time during the applied stress was almost constant. It the light of these facts, it is estimated that varistor constituents having 2.0mol% and 4.0mol% yittria, respectively, will be utilized to various application fields.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.892-894
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• 1995

This paper deals with developmeant and application of coating thickness control system in hot dip galvanizing process. According to the line conditions, such as line speed, strip size and target coating weight, a predictive preset model sets the initial oprating conditions. Referring the zine coating informations from the gauge, mean coating value controller adjusts the chamber pressure and horizontal distance between strip and air knife, while coating deviation controller adjusts the lip gap profile of the air knife. All adaptive gains are interactively calculated by numeric models based on the theoretical analysis. The operating result with this system effectively reduces the coating deviation in transverse direction as well as in longitudinal direction.