• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.1
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• pp.20-35
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• 2023

Chemical preservatives have a good effect on antibacterial activity, but many side effects on the human body have been reported. Recently, the development of natural preservatives that are harmless to the human body and have preservative functions and self-efficacy is active. In addition, in order to increase the absorption rate of natural products by the human body, the method of fermentation using strains is also increasing. Therefore, this study selected varieties that are harmless to the human body and have good antibacterial activity. 1. The yield of origin, thickness and solvent was investigated. Scutellaria baicalensis Georgi was made in China and received a yield of 21.88% from 50% ethyl alcohol extract. Salvia miltiorrhiza Bunge was made in Korea and received a yield of 25.62% from 50% ethyl alcohol extract. Dryopteris crassirhizoma Nakai was made in China and received a yield of 6.50% from 70% ethyl alcohol extract. 2. The solid fermentation with the S. baicalensis and S. miltiorrhiza with B. Subtilis yield gained 24.40%, 39.30%, and D. crassirhizoma obtained 11.10% yield when fermented with L. casei. 3. After the liquid fermentation, a clear zone of 9mm was identified for the S. aureus strain in the S. baicalensis, and the antibacterial activity was not confirmed in S. miltiorrhiza and D. crassirhizoma. 4. When the S. baicalensis was fermented with L. Casei, it showed high antibacterial activity in C. albicans and S. aureus. S. miltiorrhiza showed antibacterial activity in S. aureus when it was solid with S. cerevisiae. When the spectators were solid with L. casei and S. cerevisiae, antibacterial activity was high in E. coli and S. aureus. Overall, the antibacterial activity after fermentation was much higher than when fermented. 5. The change in active ingredients was baicalin 101.57, baicalein 28.26, and wogonin 5.33mg/g in the S. baicalensis that did not ferment solid. When solid fermentation with S. cerevisiae, the content of baicalinin with baicalin 94.31, baicalein 30.41, and wogonin 3.57mg/g was found to have increased. S. miltiorrhiza that was not fermented, salvianolic acid A was 1.82mg/g, and when fermented with S. cerevisiae, it increased to 5.70mg/g. The active ingredients of the spectators were flavaspidic acid AP, flavaspidic acid PB, flavaspidic acid AB, and flavaspidic acid BB.

• Polymer(Korea)
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• v.32 no.2
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• pp.143-149
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• 2008

We synthesized PEG-PLA (or PLGA) amphiphilic di-block copolymers, which consist of PEG as biocompatible and hydrophilic block and PLA (or PLGA) as biodegradable and hydrophobic block, by ring opening polymerization of LA in the presence of methoxy PEG as a macroinitiator. The compositions and the molecular weights of the copolymers were controlled by changing the feed ratio of LA (and GA) to PEG initiator. The di-block copolymers could self-assemble in aqueous media to form micellar structure. A hydrophobic model drug, pioglitazone, was loaded into the polymer micelle using solid dispersion and dialysis methods, and the drug-loaded micelles were characterized by AFM, DLS and HPLC measurements. The drug loading capacity and in vitro release studies were performed and evaluated under various conditions. These results indicated that the amphiphilic di-block copolymers of PEG-PLA (or PLGA) could solubilize pioglitazone by solid dispersion method and the drug release was modulated according to micellar chemical compositions.

• Geomechanics and Engineering
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• v.13 no.1
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• pp.1-23
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• 2017

A coupled liquid-gas-solid three-phase model, linking two numerical codes (TOUGH2/EOS3 and $FLAC^{3D}$), was firstly established and validated by simulating an in-situ air flow test in Essen. Then the coupled model was employed to investigate responses of multiphase flow and soil skeleton deformation to compressed air or freshwater injection using the same simulation conditions in an aquifer of Tianjin, China. The simulation results show that with injecting pressurized fluids, the vertical effective stress in some area decreases owing to the pore pressure increasing, an expansion of soil skeleton appears, and land uplift occurs due to support actions from lower deformed soils. After fluids injection stops, soil deformation decreases overall due to injecting fluids dissipating. With the same applied pressure, changes in multiphase flow and geo-mechanical deformation caused by compressed air injection are relatively greater than those by freshwater injection. Furthermore, the expansion of soil skeleton induced by compressed air injection transfers upward and laterally continuously with time, while during and after freshwater injection, this expansion reaches rapidly a quasi-steady state. These differences induced by two fluids injection are mainly because air could spread upward and laterally easily for its lower density and phase state transition appears for compressed air injection.

• Journal of the Korean Society for Heat Treatment
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• v.7 no.4
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• pp.244-252
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• 1994

The morphological changes of primary solid particles as a fuction of process time on Al-Si alloys during semi-solid state processing with a shear rate of 200s were studied. In hypereutectic Al-15.5wt%Si alloy, it was observed that primary Si crystals are fragmented in the early stage of stirring and morphologies of primary Si crystals change from faceted to spherical during isothermal shearing for 60 minutes. In quaternary Al-12.5wt%Si-2.9wt%Cu-0.7wt%Mg alloy system, it was observed both primary silicon and ${\alpha}$-alumunum particles. Microstructural evolution of primary Si crystals was similar to that of the hypereutectic Al-Si alloy but equiaxed ${\alpha}$-Al dendrites are broken into nearly spherical at the early stage of shearing and later stage of the isothermal shearing ${\alpha}$- Al particles are slightly coarsoned by Ostwald ripening. Mechanical properties of Al-Si-Cu-Mg alloy were compared to those from other processes (squeeze casting and gravity casting). After T6 heat treatment, comparable values of hardness were obtained while slightly lower compressive strength values were observed in rheocast alloy. The elongation, on the other hand, exhibited significant increasement of 15% over gravity cast alloy.

• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.101-109
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• 1999

This study attempts to analyse the solid mixing in the feeder and the packing effect for pressure fluctuations in the fluidized bed. To study the mixing characteristics of solid in vibrating feeder for the stable operations of fluidized combustion, the system consisted of two groups of particles such that fine particles were located on the top of the coarse particles before vibratory mixing had started. The effects of packing materials on the pressure fluctuations in a fluidized bed were analysed by using a statistical method to interpret the behavior of fluidized bed. The experiments were carried out in a fluidized bed of 6.7cm-ID, and the experimental variables were particle sizes, of 115 to 1,015$\mu\textrm{m}$ in diameter and the multi-sized particles haying Rosin-Rammler and Gaussian distributions. The settled bed heights of particles to diameter ratios (L/D) were ranged from 0.5 to 2.0. And fluidizing of particles was carried out by air. The packing materials used were screen packing, and the properties of the pressure fluctuations in the fluidized bed were measured by a differential pressure transducer. The properties of the pressure fluctuations calculated were the mean, the standard deviation, and the major frequency of the power spectral density functions. From the characteristics of fluidizing, it was found that the standard deviation of pressure fluctuations could be effectively used to explain the fluidized phenomena, and the packing materials affected severely the properties of the pressure fluctuations. As a result, from the interpretation by spectral analysis, the effects of measuring radius of pressure fluctuations on standard deviation were constant in the case of the fluidized bed with and without packing materials. However, the effects of measuring the height of pressure fluctuations on standard deviations were linear increasing for the fluidized bed with packing materials, but were constant for the fluidized bed without packing materials at 4.5cm above the gas distributor. The major frequency of pressure fluctuations was found to be nearly independent of fluidized system. Also, the major frequency of pressure fluctuations decreased with increasing packing size, and it had maximum value at 10% of the packing amount.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.2
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• pp.98-111
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• 2008

This review introduces advances in clinical and pre-clinical single photon emission computed tomography (SPECT) and positron emission tomography (PET) providing noninvasive functional images of biological processes. Development of new collimation techniques such as multi-pinhole and slit-slat collimators permits the improvement of system spatial resolution and sensitivity of SPECT. Application specific SPECT systems using smaller and compact solid-state detector have been customized for myocardial perfusion imaging with higher performance. Combined SPECT/CT providing improved diagnostic and functional capabilities has been introduced. Advances in PET and CT instrumentation have been incorporated in the PET/CT design that provide the metabolic information from PET superimposed on the anatomic information from CT. Improvements in the sensitivity of PET have achieved by the fully 3D acquisition with no septa and the extension of axial field-of-view. With the development of faster scintillation crystals and electronics, time-of-flight (TOF) PET is now commercially available allowing the increase in the signal-to-noise ratio by incorporation of TOF information into the PET reconstruction process. Hybrid PET/SPECT/CT systems has become commercially available for molecular imaging in small animal models. The pre-clinical systems have improved spatial resolution using depth-of-interaction measurement and new collimators. The recent works on solid state detector and dual modality nuclear medicine instrumentations incorporating MRI and optical imagers will also be discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.4
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• pp.298-303
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• 2012

$Y_{1-x}VO_4:Eu_x^{3+}$ red phosphors were synthesized with changing the mol ratios of $Eu^{3+}$ ions by using the solid-state reaction method. The crystalline structure of phosphors was found to be a tetragonal system with the maximum diffraction intensity at $25.02^{\circ}$. The grain particles showed the truncated hexagonal patterns with a very homogeneous size distribution at 0.05 mol of $Eu^{3+}$ ion. The excitation spectra of the phosphor ceramics were composed of a broad band centered at 303 nm and weak narrow multilines peaked in the range of 360-420 nm. The dominant emission spectrum was the strong red emission centered at 619 nm due to the $^5D_0{\rightarrow}^7F_2$ electric dipole transition. The experimental results suggest that the optimum doping mol ratio of $Eu^{3+}$ ions for preparing the red phosphors is 0.10 mol with the asymmetry ratio of 5.21.

• The Korean Journal of Food And Nutrition
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• v.18 no.4
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• pp.373-379
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• 2005

The volatile components of Pinus densiflora needles were studied by gas chromatography-mass spectrometry(GC-MS), using seven kinds of solid phase microextraction (SPME) fibers, seven in SPME fibers: 100 ${\mu}m$ PDMS, 65 ${\mu}m$ PDMS/DVB, 65 ${\mu}m$ SF-PDMS/DVB, 85 ${\mu}m$ PA, 75 ${\mu}m$ CAR/PDMS, 65 ${\mu}m$ CW/DVB and 50/30 ${\mu}m$ DVB/CAR/PDMS fibers. A total of 40 components were identified by using the seven different SPME fibers. The identified components were classified, according to their functionalities, as follows: 26 hydro-carbons, 7 alcohols, 4 carbonyl compounds, and 3 esters. The major volatile components of Pinus densiflora needles identified by these SPME fibers were $\alpha$-pinene ($1.7\~21.7\;{\mu}g/g$), $\beta$-myrcene ($2.0\~20.1\;{\mu}g/g$), $\beta$-phel-landrene ($4.6\~22.8\;{\mu}g/g$), $\beta$-caryophyllene ($6.7\~26.0\;{\mu}g/g$) germacrene D ($1.1\~11.9\;{\mu}g/g$). In the comparison of the seven SPME fibers, PDMS appeared to be the most suitable fiber for the analysis of hydrocarbon compounds and CAR/DPMS, PDMS/DVB, CW/VB and DVB/CAR/PDMS are shown to be optimal for analysis of the alcohols and carbonyl compounds.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.651-657
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• 2020

Fluidization processes in which solid particles vividly move like gas or liquid have been widely used in various industrial sectors, such as thermochemical energy conversion and polymerization processes for general purpose polymer resins. One of the general purpose polymer resins, LLDPE(Linear low-density polyethylene) resins have been produced in bubbling fluidized bed processes in the world. In a bubbling fluidization polymerization reactors, LLDPE particles with relatively larger particle size and low density are fluidized by hydrogen gas for polymerization reaction. Though LLDPE polymerization reactors are one of bubbling fluidization processes, slugs that have negative impact for reaction exist or occur in these processes. Therefore, the fluidization state of LLDPE particles was investigated in a simulation model similar to a pilot-scale polymerization reactor (0.38 m l.D., 4.4 m High). In particular, the effect of gas velocity (0.45-1.2 m/s), solid density (900-199 kg/㎥), solid sphericity (0.5-1.0), and average particle size (120-1230 ㎛), on bed height and fluidization state were measured by using a CPFD(Computational particle-fluid dynamics) method. With CPFD analysis, the occurrence of a flat slug was visualized. Also, the change in particle properties, such as particle density, sphericity, and size, could reduce the occurrence of slug and bed expansion.

• Korean Journal of Materials Research
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• v.24 no.9
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• pp.469-473
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• 2014

$SrSnO_3$ phosphor powders were synthesized with two different contents of activator ions $Eu^{3+}$ and $Tb^{3+}$ using the solid-state reaction method. The structural, morphological, and optical properties of the phosphors were investigated using X-ray diffractometry, field-emission scanning electron microscopy, and fluorescence spectrophotometry, respectively. All the phosphors showed a cubic structure, irrespective of the type and the content ratio of activator ions. For $Eu^{3+}$-doped $SrSnO_3$ phosphors, the intensity of the 620 nm red emission spectrum resulting from the $^5D_0{\rightarrow}^7F_2$ transition of $Eu^{3+}$ was stronger than that of the 595 nm orange emission signal due to the $^5D_0{\rightarrow}^7F_1$ transition in the range 0.01-0.05 mol of $Eu^{3+}$, but the ratio of the intensity was reversed in the range 0.10-0.20 mol of $Eu^{3+}$. The variation in the emission intensity indicates that the site symmetry of the $Eu^{3+}$ ions around the host crystal was changed from non-inversion symmetry to inversion. For the $Tb^{3+}$-doped $SrSnO_3$ phosphors under excitation at 281 nm, one strong green emission band at 550 nm and several weak bands were observed. These results suggest that the optimum red and green emission signals can be realized when the activator ion content for $Eu^{3+}$- or $Tb^{3+}$-doped $SrSnO_3$ phosphors is 0.20 mol and 0.15 mol, respectively.