• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.1
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• pp.21-28
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• 2017

The steel-plate concrete(SC) is used in a form of module assembly construction in the outer wall of nuclear-power plant and LNG containment. Since the steel-plate concrete modules are generally manufactured from the plant, the weight of SC has significantly effect on the total construction cost in the aspect of shipment. Therefore, the use of lightweight aggregates concrete(LWAC), which fill the inside of SC module can be a solution. However, the amount of used lightweight aggregates(LWA) is limited in the use of current concrete mixing process due to the concrete quality problems and it also determines the allowable minimum density of LWAC. In this research, the preplaced casting method is applied because of increasing the volume fraction of LWA significantly, which results from the producing process of pre-packing the LWA in the formwork and filling the interstitial voids between LWA using cement paste grout. The density and compressive strength of selected preplaced LWAC were $1,600kg/m^3$ and 30MPa and it was applied for the mock-up specimens of SC panel. It was used for the 3-point bending test for evaluating its structural performance. The results show that the preplaced LWAC can reduce the density of concrete with the adequate mechanical and structural performance.

• Journal of the Korean Magnetics Society
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• v.1 no.2
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• pp.60-68
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• 1991

In compacting the melt-spun $Nd_{14}Fe_{76}Co_{4}B_{6}$ and $Nd_{10.5}Fe_{79}Co_{2}Zr_{15}B_{7}$ magnetic powders. the difference in composition induces a different behavior of closed packing rate as a function of aspect ratio of the powders. The $Nd_{10.5}Fe_{79}Co_{2}Zr_{1.5}B_{7}$ alloy having a low Co/Fe ratio (low density) shows the better green density to have an enhanced closed packing rate. An empirical power equation relating the green density with the compacting pressure was obtained such as ${\phi}(g/cm^{2})=5.2~5.6{\times}P^{0.045~0.065}(ton/cm^{2})$. The $Nd_{14}Fe_{76}Co_{4}B_{6}$ alloy having a high Nd/Fe ratio possesses much finer grain size(50~60 nm) than that of $Nd_{10.5}Fe_{79}Co_{2}Zr_{1.5}B_{7}$ alloy and shows the higher coercivity($iH_{c}=14~15kOe$). The higher Nd/Fe ratio in the melt-spun Nd-Fe-Co-B alloy, where the domain wall pinning mechanism was found to be predominant, assists the formation of Nd-rich grain boundary phase acting as a pinning site. The grain boundary ranges over $12~16\;{\AA}$ thick in the Nd-Fe-Co-B alloy while it ranges over $8~12\;{\AA}$ thick in the Nd-Fe-Co-Zr-B alloy.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.4
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• pp.333-339
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• 2003

New manufacturing process was applied to manufacture the low salted Squid-Jeotgal to improve the quality variation salty taste and shelf-life. It's optimum salting and sugaring process was made by the addition of $17\%$ NaCl for 3 hr and $15\%$ corn syrup for 4 hr with 10 rpm agitation. Quality variations of Squid-Jeotgal produced by the improved and the conventional process were packed by jar, polyethylene lerephthalatefpolyethyleneilinear low density polyethylene (PET) and low density polyethylene (PE). And then quality variations of them were investigated at storage temperature of 10, 20, and $30^{\circ}C.$ Decreasing rate of pH, increasing rates of VBN and viable cell counts of Squid-Jeotgal produced by the improved process were slower than those of the conventional process at all storage temperature. Sensory evaluation indicated that the production of Squid-Jeotgal by the improved process extended the shelf-life about 10-20 days.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.2
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• pp.303-311
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• 1994

Optimum conditions for the deposition of N-docosylquinolium-TCNQ ultrathin organic films using the Langmuir-Blodgett etchnique and the molecular orientation and alignment of the LB films were studied. The $\pi$-A isotherm of the N-docosylquinolium-TCNQ was measured at the air-water interface varying with the subphase temperature, subphase pH, compressing speed and amounts of solutions for spreading. The LB film was deposited under the surface pressure of 30mN.m and 45mN/m and other deposition conditions. The molecular orientation and alignment of the LB films were studied by the polarization absorption technique. The $\pi$-A isotherm showed that the stable N-docosylquinolium -TCNQ monolayer was formed on the water surface at the condition of 25$^{\circ}C$,pH 5.6, molecular density of 2.1${\times}$10S014T~2.6${\times}$10S014T/cmS02T. The LB film was deposited under the surface pressure of 45mN/m had better packing density, orientation and alignment than the film of 30mN/m.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.276-279
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• 2000

When high temperature superconducting tapes is fabricated using the PIT (Powder In Tube) method, the length of HTS tapes is increased more than 500 ${\sim}$ 1,000 times of initial powder packed billet. On mechanical processing, heterogeneous properties between the ceramic superconducting core and Ag/Ag alloy sheath occur the non-uniformity deformation as like sausaging that deteriorate the critical current properties of HTS tapes. In this study, we investigated the workability of Bi-2223/Ag/Ag alloy sheath tapes fabricated by the PIT method involving a number of different mechanical processes, multi drawing and rolling. In order to obtain the high critical current density and high uniformity of Bi-2223/Ag sheath tapes, the influences of powder packing density, drawing die angle and rolling parameters were studied. We found that the roll diameter is an important variable in the rolling process, as critical current of tapes rolled using 250 mm rolls was higher than that using 150 mm rolls.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.6
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• pp.606-613
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• 2003

This study investigated the effects of food type (condensed freshwater Chlorella, dried Chlorella, dried Spirulina, dried Schizochytrium, baker's yeast and $\omega-yeast$) and amount, and supplementation of vitamin $B_{12}$ on the growth of freshwater rotifer (Brachionus calyciflorus) in high density culture. Growth of rotifers fed condensed freshwater Chlorella was the highest and its density ranged $7.65-8.14{\times}10^3\;inds./mL.$ The primary lipid acids of rotifers fed condensed freshwater Chloyella were linoleic and linolenic, and their amount ($\%$ of total fatty acids) were $48.8\%\;and\;26.8\%,$ respectively. This suggests that condensed freshwater Chlorella would be an effective diet for high quality and quantity rotifers, which in turn serve as live food for freshwater fish larvae. Growth rate of rotifers with Chlorella supplementation increased as amount of supplementation increased up to 1.5 and 2.5 mg at 28 and $32^{\circ}C$, respectively. However, undissolved ammonia toxicity and packing volume of Chlorella in culture medium, reached the optimal conditions for the stable and effective cultivation of rotifers when amount of condensed freshwater Chlorella was 1.5 mg in dry weight per 1,000 rotifers at $28^{\circ}C\;and\;32^{\circ}C$ Growth of rotifers in condensed freshwater Chlorella with vitamin $B_{12}$ supplementation was significantly higher than that of rotifers without supplementation. However, no significant difference was found among the different concentrations of vitamin $B_{12}.$ Therefore, vitamin $B_{12}$ could improve the growth of rotifers (B. calyciflorus).

• ETRI Journal
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• v.7 no.4
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• pp.11-14
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• 1985

A polysilicon self-aligned bipolar n-p-n transistor structure is described, which can be used in high speed and high packing density LSI circuits The emitter of this transistor is separated less than $0.4\mum$ with base contact by polysilicon self-align technology. Through all the process, the active region of this device is not damaged. therefore a high performance device is obtained. Using the transistor with $3.0\mum$ design rules, a CML ring oscillator has per-gate minimum propagation delay time of 400 ps at 2.7 mW power consumption condition.

• Korea-Australia Rheology Journal
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• v.20 no.2
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• pp.65-71
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• 2008

Pressure filtration technique was used to obtain defect-free microstructure of green cast ceramic bodies. Stable alumina suspensions of desired rheology (<5 Pa s at $1\;s^{-1}$) containing 60-80 mass. % solid loading were prepared in the alkaline region (at $pH{\approx}9$) with an optimum amount of 0.5 dmb % of Tiron added. Acidic region (at $pH{\approx}4$) enabled the preparation of 60 mass. % suspensions with addition of 1.5 dmb % of Tiron. The best quality slip was processed from an 80 mass.% suspension with 63% of theoretical density. The homogeneity of particle packing and the absence of defects in microstructure were proven by narrow pore size distribution (ranging from 32 to 64 nm, with up to 85% abundance), confirming advantages of the wet consolidation route.

• Transactions of Materials Processing
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• v.17 no.7
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• pp.486-490
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• 2008

This study demonstrates that preloading via the elastostatic compression imposed on amorphous alloys at room temperature induces homogeneous plastic strain associated with structural disordering. This structural disordering causes disorder, which at room temperature creates excess free volume and in turn enhances the plasticity. In this study, we investigated the effects of various parameters, such as stress level, flow rate and preloading time, on the degree of the structural disordering at room temperature. On the basis of the present findings, we proposed a method of enhancing the plasticity of amorphous alloys.

• Journal of the Korean Ceramic Society
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• v.34 no.12
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• pp.1227-1234
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• 1997

ZnO thin films were prepared by rf-magnetron sputter at various conditions. Crystallinity, microstructure, chemical composition, and optical composition, and optical properties of the films were investigated as functions of substrate temperature (R. T.-50$0^{\circ}C$) an sputter gas (O2/Ar=0-50%). ZnO thin films grown at 50$0^{\circ}C$ with sputter gas of pure argon as well as at R. T. with sputter gas of a mixture of argon & oxygen(O2/Ar=2%) exhibit a strong tendency of (002) preferred orientation, compared with a considerable random orientation at the other conditions. The thin films with (002) preferred orientation has a chemical stoichiometry of Zn/O-1.01, a band gap of 3.3eV, and a packing density of 98% respectively.