• Nuclear Engineering and Technology
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• 제30권2호
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• pp.99-111
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• 1998

Chemical composition of the insoluble residue in a simulated spent PWR fuel(SIMRJEL) were studied. SIMFUELS were prepared by adding calculated amount of FP(fission product) elements with a burnup of 3.6% FIMA(fission per initial metal atom) to uranium in nitrate solution, evaporating the mixed solution to dryness, calcining at 90$0^{\circ}C$ in a stream of 4% H$_2$ + 96% He, and heating the pellet at 140$0^{\circ}C$ under high and low oxygen potentials. Insoluble residue was obtained from the dissolution of the SIMFUEL with HNO$_3$(1 : 1). The chemical composition of the SIMFUELs and the insoluble residues was determined by EPMA(electron probe microanalysis), XPS(X-ray photoelectron spectroscopy) and by XRD (X-ray diffraction) measurements. All of the insoluble residues suspended and precipitated were composed mainly of Mo, Ru with a small amount of Zr, Rh, Pd and Cd. The amount of insoluble residue(<1 wt.%) and a Mo/Ru ratio decreased with increasing oxygen potential. Formation of the zirconium molybdate precipitate, ZrMo$_2$O$_{7}$(OH)$_2$($H_2O$)$_2$, was observed in the residues. The possible role of Mo on the phase formation was discussed in regard to oxygen potential.l.

• 분석과학
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• 제7권4호
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• pp.517-526
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• 1994

Mn의 함량을 달리하여 제조한 Al-Li-Cu-Mg-Mn-Zr 합금의 미고용상 및 분산상을 EPMA(Electron Probe Microanalyzer)와 SAEM(Scanning Auger Electron Microscope)으로 분석하였다. 또한 미고용상의 부피 분율, 분포 및 형태를 광학현미경으로 관찰하였으며, 상온과 고온에서의 인장 특성을 조사하였다. Mn의 함량이 증가함에 따라 미고용상의 부피분율을 급격히 증가하고 연신율을 감소하였다. Mn은 기지 조직의 결정립을 미세하고 균일하게 분포하도록 하였다. 인장시험 결과, 0.44 wt% Mn이 첨가된 합금이 다른 합금보다 우수한 기계적 특성을 나타내었다.

• 열처리공학회지
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• 제37권4호
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• pp.172-181
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• 2024

In this study, the effect of addition of Ti and Co elements on microstructural evolution and characteristics of vacuum-casted Cu-25%Cr electrical contact material was investigated. The coarse and insoluble Cr phases with an average size of 300 ㎛ in commercial Cu-25%Cr alloy were reduced to tens of micrometers in vacuum casted Cu-25%Cr-X(X=Ti, Co) alloy, which can be interpreted as result controlling coarsening and the work-frame structure of the insoluble Cr phase by the formation of intermetallic compounds such as Cr₂Ti or Cr_0.5Co_1.5Ti around the Cr phase As a result, the electrical properties such as weight loss and fusion resistance against the repeated arc generation of the electrical contact material as well as the mechanical properties were greatly improved.

• Journal of Microbiology and Biotechnology
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• 제2권2호
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• pp.135-140
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• 1992

The partitioning of recombinant human interleukin-2(rhII-2) in PEG 8000-dextran 38800 aqueous two-phase system has been investigated using three different sources of rhIL-2. In the case of pure rhIL-2, the solubility in a PEG-dextran two-phase system was low and most of rhIL-2 was partitioned into the bottom phase. For the recovery of rhIL-2 from insoluble protein aggregates, the inclusion bodies of recombinant E. coli were solubilized by the treatment with sodium dodecyl sulfate (SDS). The addition of SDS significantly enhanced not only the solubility of rhIL-2 but also the partitioning of rhIL-2 to the top phase. When the ratio of SDS to rhIL-2 was 2.0, the partition coefficient(K) and the recovery yield(Y) at the top phase were 4.5 and 88%, respectively, at pH 6.8. In order to reduce the recovery steps further, SDS was directly added to the intact recombinant E. coli cells and then partitioned into the PEG/dextran aqueous two-phase system. The observed partition coefficient ($K{\cong{3.0$) and recovery yield ($Y{\geq}80%$ )of this method were comparable to the rhIL-2 recovery from insoluble protein aggregates. The results obtained in this work indicate that PEG-dextran two-phase partitioning might provide a simple way for the recovery and partial purification of recombinant proteins which are produced as inclusion bodies.

• Nutrition Research and Practice
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• 제6권1호
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• pp.28-34
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• 2012

The objective of this study was to estimate the contents of dietary insoluble and soluble fiber in school meal. Samples of the school meals were collected from May to June in 2008. Three elementary schools and three middle schools around Masan area were selected for analysis. Dietary soluble and insoluble fibers in the school meals were analyzed directly by the AOAC method. From the initial experiment phase, we used cellulose and pectin as a standard of dietary fiber, and average recovery rate of insoluble fiber and soluble fiber was calculated. The recovery rate was observed, the cellulose $109.7{\pm}11.7%$ (range 90~150%) and pectin $77.8{\pm}10.8%$ (range 64.7~96.7%), respectively. The amounts of insoluble fiber and soluble fiber were analyzed in the total of 66 dishes, which included 7 kinds of cooked rice (bab) made with some cereal products and vegetables, 19 kinds of soup (guk) made with meats or vegetables, 11 kinds of kimchi, 21 kinds of entr$\acute{e}$es or side dishes, and 8 special dishes. Conclusively the school meal, per serving size, would provide above 75% KDRI of total dietary fibers through mainly soups and special menu, with the exception to fruits. In addition, it might be expected that children could consume more soluble fiber from the meals with the special dishes than from the regular ones.

• Geomechanics and Engineering
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• 제12권5호
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• pp.849-862
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• 2017

With growing interests in using bacterial biopolymers in geotechnical practices, identifying mechanical properties of soft gel-like biopolymers is important in predicting their efficacy in soil modification and treatment. As one of the promising candidates, dextran was found to be produced by Leuconostoc mesenteroides. The model bacteria utilize sucrose as working material and synthesize both soluble and insoluble dextran which forms a complex and inhomogeneous polymer network. However, the traditional rheometer has a limitation to capture in situ properties of inherently porous and inhomogeneous biopolymers. Therefore, we used the particle tracking microrheology to characterize the material properties of the dextran polymer. TEM images revealed a range of pore size mostly less than $20{\mu}m$, showing large pores > $2{\mu}m$ and small pores within the solid matrix whose sizes are less than $1{\mu}m$. Microrheology data showed two distinct regimes in the bacterial dextran, purely viscous pore region of soluble dextran and viscoelastic region of the solid part of insoluble dextran matrix. Diffusive beads represented the soluble dextran dissolved in an aqueous phase, of which viscosity was three times higher than the growth medium viscosity. The local properties of the insoluble dextran were extracted from the results of the minimally moving beads embedded in the dextran matrix or trapped in small pores. At high frequency (${\omega}>0.2Hz$), the insoluble dextran showed the elastic behavior with the storage modulus of ~0.1 Pa. As frequency decreased, the insoluble dextran matrix exhibited the viscoelastic behavior with the decreasing storage modulus in the range of ${\sim}0.1-10^{-3}Pa$ and the increasing loss modulus in the range of ${\sim}10^{-4}-1\;Pa$. The obtained results provide a compilation of frequency-dependent rheological or viscoelastic properties of soft gel-like porous biopolymers at the particular conditions where soil bacteria produce bacterial biopolymers in subsurface.

• 미생물학회지
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• 제23권2호
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• pp.90-100
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• 1985

The present study was designed to investigate cellular regulation of phosphate metabolism between catabolically repressed and derepressed states in yeast (Saccharomyces uvarum). The activities of various phospatases and the contents of phosphate compounds were detected according to the culture phase and various phosphate concentrations. As the results, Saccharomyces uvarum derepressed many phosphate metabolizing enzymes such as alkaline phosphatase, acid phosphatase and ATPase more than ten fold simultaneously during catabolic repression (phospgate and sugar starvation). At the same state, the amounts of orthophosphate, nucleotidic labile phosphate and acid soluble polypgosphate were increased, compared to basal levels of normally cultivated cells. $Mg^{++}-stimulated$ type among all phospatases was appeared to have most of the enzyme activity. It could be postulated that $K^+ -stimulated$ alkaline phosphatase was directly or indirectly correlated with the synthesis of acid insoluble polyphosphate $Mg^{++}-stimulated$ phosphatase with the degradation of polyphosphates. In case of cultivation in the medium supplemented with sugar and phosphate (catabolic derepression), phospgatase activities except for alkaline phosphatase were decreased rapidly through the progressive batch culture, After 12 hrs culture, at early exponential phase, the cellular accumulation of acid insoluble polyphosphate increased about 5 fold, compared to those of the starved cells. Under catabolic repression, it could be postulated that intracellular phosphate metabolism was regulated by derepressions of phosphatases. The function of polyphosphate system was shown to compensate the ATP/ADP system as phosphate donor and energy source especially during catabolic repression.

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2003년도 춘계 학술발표회 논문집
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• pp.66-68
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• 2003

Polycyclic Aromatic Hydrocarbons (PAHs) are hydrophobic and most are practically insoluble in water contributing to their persistence in the environment. In addition, most exist in strongly adsorbed forms when they are introduced into the soils. Their removal efficiency can be limited in low mass transfer phases, such as PAHs-contaminated soils, because most chemical and biological remediation technologies require transfer from NAPs (Non-Aqueous Phase Liquids) into the mobile phase. (omitted)

• Bulletin of the Korean Chemical Society
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• 제12권3호
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• pp.334-342
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• 1991

To investigate the phase equilibria and structural properties of microemulsions, we study a simple phenomenological model on the basis of the cubic lattice cell with which the oil- and water-filled cells are connected one another, respectively. The surfactant is assumed to be insoluble in both oil and water, and to be adsorbed at the oil-water interface. The Schulman condition, according to which the lateral pressure of the surfactant layer is compensated by the oil-water interfacial tension, is found to hold to good approximation in the middle-phase microemulsion. Our results show that the oil- and water-filled domains in that microemulsion are about 50-150 $\AA$ across, and depend sensitively on the curvature parameters. The phase diagram is not symmetric in this model. It may be asymmetrized intrinsically by non-equivalency of oil and water. The two- and tree-phase equilibria including critical points and critical endpoints are found.

• Journal of Dairy Science and Biotechnology
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• 제35권2호
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• pp.85-92
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• 2017

Four different types of cheeses were measure detailed changes in the mineral concentrations of cheese-serum during ripening. Concentrations of minerals in cheese juice were measured. The pH value using the low pH method (LPM) cheese was significantly (p<0.05) lower than that of other cheeses. Similarly the total Ca, S, Mg, and P contents of LPM cheese were significantly lower in than those of other cheeses. Ca, S, Mg, and P remained in colloidal form, while other minerals were mostly in soluble forms after 1 day. The minerals associated with the structure of cheese (i.e., casein or colloidal calcium phosphate) remained largely insoluble even after 1 month of ripening.