• Analytical Science and Technology
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• v.10 no.6
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• pp.439-444
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• 1997

Twelve kinds (1set) standard materials of chemical ingredients of lead zirconate titanate[$Pb(ZrTi)O_3$] have been developed in order to determine fast and accurate measurement of X-ray fluorescence spectrometry. Especially, we used diluted(ahout sixteen times) filling compound($Li_2B_4O_7/LiBO_2=4/1$) to consider removal effect of matrix, storage convenience, and homogenous characteristics. As a result from the four different laboratories, we obtained extremly good agreement about the standard curve on twelve standard materials which containing eleven elements, PbO, $ZrO_2$, $TiO_2$, SrO, $WO_3$, $La_2O_3$, $Cr_2O_3$, MgO, $Nb_2O_5$, and $MnO_2$. The correlation factor of standard curve was over 0.998. However, ZnO has relatively low correlation factor, 0.977, because the concentration was 10ppm lower than other original materials. This analysis reveals that ZnO has shown the poor linearity as well as low fluorescence intensity. In present work, XRF standard materials are useful for determining a rapid and accurate results for major and minor elements concentration among PZT.

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.265-271
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• 2010

Desalination effects of capacitive deionization (CDI) process was studied using $TiO_2$/activated carbon electrode. In order to enhance the wettability of electrode and decrease a electrode resistance, $TiO_2$ was coated on activated carbon. By means of $TiO_2$ coating on activated carbon, electric double layer to adsorption content in CDI process was increased. It was identified from TEM, XRD, and XPS that the activated carbon based on $TiO_2$ composite was fabricated successfully by means of sol-gel method. As a results of cyclic voltammetry and impedance, it was identified that $TiO_2$/activated carbon electrode has more electric double later capacitance and less diffusion resistance than activated carbon. Also charge-discharge and ion conductivity profiles showed that the ion removal ratios of $TiO_2$/activated carbon electrode in NaCl electrolyte of $1000\;{\mu}S/cm$ more increased about 39% than that of activated carbon. In conclusion it was possible to identify that the carbon electrode coated $TiO_2$ as electrode material was more effective than raw carbon electrode.

• Applied Biological Chemistry
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• v.34 no.4
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• pp.373-378
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• 1991

The skin and fleshy substance on the net fiber of sponge-gourd fruit pressed mechanically was removed with 0.2% NaOH solution in $3{\sim}5$ hours. The treatment of 0.2% NaOH with 0.02% Monopol(non-ionogenic polyoxethylen derivative) as surfactnat and with 0.1% $Ca(OCl)_2$ as bleaching agent enhanced the effect to remove the fleshy substance and improve the quality of net fiber. Also, the wet hardness and tensile strength of net fiber were controlled by the crosslinkage of the fiber with glu tardialdehyde, glyoxal, and formalin, respectively. The net fiber was stable on the acid and alkaline solutions. Also the range of temperature to degradate the fiber was $338{\sim}385^{\circ}C$. These values indicated a fair stability. The improved net fiber can be used for raw material of bath, dish washing, oil and gas filter, and many kinds of decorations.

• Korean Journal of Food Science and Technology
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• v.49 no.5
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• pp.538-543
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• 2017

Astringent persimmon (Diospyros kaki Thunb. cv. Cheongdo-Bansi) peel with the astringency removed, which is a by-product of dried persimmon (gotgam), was investigated for its antioxidant and neuroprotective properties. A mixture of peel and 40% (v/v) aqueous ethanol was subjected to ultrasonication and then thermal and nonthermal treatments, to produce thermally-treated and nonthermally-treated persimmon peel extracts (TPE and NTPE, respectively). The total phenolic and flavonoid contents and the antioxidant capacity of TPE was approximately 1.3-1.8 times higher than those of NTPE. TPE resulted in the increased viability of neuronal PC-12 cells compared with NTPE. Furthermore, intracellular oxidative stress in PC-12 cells was more decreased by treatment with TPE than NTPE. Cholinesterases, such as acetylcholinesterase and butyrylcholinesterase, were more inhibited by treatment with TPE than NTPE. These results suggest that TPE is useful as a functional material to decrease oxidative stress in neuronal cells and to inhibit cholinesterases.

• Journal of Life Science
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• v.21 no.11
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• pp.1599-1606
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• 2011

To evaluate the effects of microorganism agents on oil biodegradation, treatability and microcosm studies were conducted. Petroleum oil degrading bacteria were isolated from enriched cultures of oil-contaminated sediment samples using a mineral salts medium (MSM) containing 0.5% Arabian heavy crude oil as the sole carbon source. After a 5 day-incubation period using MSM, mixed microorganisms of three species (strains BS1, BS2 and BS4) degraded 48.4% of aliphatic hydrocarbons and 30.5% of aromatic hydrocarbons. Treatability and microcosm tests were performed in the three different treatment conditions (AO: Arabian heavy crude oil, AO+IN: Arabian heavy crude oil+inorganic nutrient, AO+IN+MM: Arabian heavy crude oil+inorganic nutrient+mixed microorganism agents). Among these, significantly enhanced biodegradation of aliphatic hydrocarbons were observed in AO+IN and AO+IN+MM conditions, without showing any different biodegradation rates in either condition. However, the degradation rates of aromatic hydrocarbons in an AO+IN+MM condition were increased by 50% in the treatability test and by 13% in the microcosm test compared to those in an AO+IN condition. Taken together, it can be concluded that mixed microorganism agents enhance the biodegradation of aliphatic and aromatic hydrocarbons in laboratory, a treatability test, and a microcosm test. This agent could especially be a useful tool in the application of bioremediation for removal of aromatic hydrocarbons.

• Clean Technology
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• v.26 no.2
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• pp.131-136
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• 2020

Biomass bamboo charcoal is utilized as anode for lithium-ion battery in an effort to find an alternative to conventional resources such as cokes and petroleum pitches. The amorphous phase of the bamboo charcoal is partially converted to graphite through a low temperature graphitization process with iron oxide nanoparticle catalyst impregnated into the bamboo charcoal. An optimum catalysis amount for the graphitization is determined based on the characterization results of TEM, Raman spectroscopy, and XRD. It is found that the graphitization occurs surrounding the surface of the catalysis, and large pores are formed after the removal of the catalysis. The formation of the large pores increases the pore volume and, as a result, reduces the surface area of the graphitized bamboo charcoal. The partial graphitization of the pristine bamboo charcoal improves the discharge capacity and coulombic efficiency compared to the pristine counterpart. However, the discharge capacity of the graphitized charcoal at elevated current density is decreased due to the reduced surface area. These results indicate that the size of the catalysis formed in in-situ graphitization is a critical parameter to determine the battery performance and thus should be tuned as small as one of the pristine charcoal to retain the surface area and eventually improve the discharge capacity at high current density.

• Journal of the Korea Concrete Institute
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• v.22 no.1
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• pp.41-50
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• 2010

Long-term floor deflection caused by excessive construction load became a critical issue for the design of concrete slabs, as a flat plate is becoming popular for tall buildings. To estimate the concrete cracking and deflection of an early age slab, the construction load should be accurately evaluated. The magnitude of construction load acting on a slab is affected by various design parameters. Most of existing methods for estimating construction load addressed only the effects of the construction period per story, material properties of early age concrete, and the number of shored floors. In the present study, in addition to these parameter, the effects of shore stiffness and concrete cracking on construction load were numerically studied. Based on the result, a simplified method for estimating construction load was developed. In the proposed method, the calculation of construction load is divided to two steps: 1)Onset of concrete placement at a top slab. 2)Removal of shoring. At each step, the construction load increment is distributed to the floor slabs according to the ratio of slab stiffness to shore stiffness. The proposed method was compared with existing methods. In a companion paper, the proposed method will be verified by the comparison with the measurements of actual construction loads.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.423-435
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• 1995

The purpose of this study was to observe the effect of TGF-βl, which promotes differentiation and proliferation of osteoblasts, on bone regeneration. Experimental bone defects that measured 3 mm in diameter were created on the mandibles of guinea pig by removal of bone with the use of trephine burs. In one side of mandibular body, the experimental groups, bone defects were grafted with Biogran(Orthovita Co., U.S.A) and TGF-β1(R&D System Co., U.SA). In the remaining side of the mandiblar body, the control groups, bone defects were grafted with only Biogran. Guinea pigs in the control and experimental groups were serially terminated by fours on the 3 days, the 1 week, the 2 weeks, the 3 weeks, and the 4 weeks after experiment, and both sides of the mandibular bodies were removed and fixed with 10％ neutral formalin. They were decalcified and embedded in paraffin as using the usual method. The specimen sectioned and stained with hematoxylin and eosin. Also, they were radiographed with a soft X -ray apparatus. The obtained results were as follows; 1. Hemorrhagic condition, observed in the granulation tissues, disappeared on the 1 week after experiment in both groups, and more prominent in the experimental group. The granulation tissues of the experimental group had larger number of cells than those of the control group. 2. Osteoblastic differentiation in the margin of grafted material and adjacent bone was observed on the 1 week after experiment in both groups. Also, bone formation was observed in immature form on the 1 week after experiment. and more prominent in the experimental group. 3. In the polarizing microscopic examination, bone matrix was very loose on the 1 week after experiment, but increase in density with time, and more prominent in the experimental group. 4. In the microradiographic examination, newly formed bone was observed in the experimental group on the 2 weeks after experiment, and this was observed earlier than in the control group. Newly formed bone was increased with time and defected area was markedly decreased on the 4 weeks after experiment.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.5
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• pp.514-525
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• 2001

The purpose of this study was to compare the marginal fit of provisional restorations by differentiating the removal time and setting temperature during resin polymerization. After mixing autopolymerizing methyl methacrylate resin, the material was placed in a preformed resin shell crown. The crown was seated on a die with 1mm shoulder margin. Crowns were removed after 3, 4, 5, 6 minutes and polymerization was continued under the following conditions : $25^{\circ}C$ air, $30^{\circ}C,\;40^{\circ}C,\;50^{\circ}C,\;60^{\circ}C,\;70^{\circ}C$ water. After polymerization. the crown was sectioned. The marginal & occlusal discrepancies were measured. The mean marginal discrelpancies at 3 minutes, 4 minutes, 5 minutes and 6 minutes of removing time were $96.6{\mu}m.\;84.6{\mu}m,\;86.7{\mu}m$ and $105.6{\mu}m$. The mean occlusal discrepancies at 3 minutes, 4 minutes, 5 minutes and 6 minutes of removing time were $106.7{\mu}m,\;89.3{\mu}m,\;98.6{\mu}m$ and $127.7{\mu}m$. There was significant difference between 4 minutes group and 6 minutes group in occlusal discrepancies. The mean marginal & occlusal discrepancies for crowns polymerized in $25^{\circ}C$ air were $98.2{\mu}m$ and $124.1{\mu}m$. The crowns polymerized in $50^{\circ}C$ water demonstrated the smallest marginal & occlusal. discrepancies. The mean value of marginal & occlusal discrepancies in $50^{\circ}C$ water were $73.1{\mu}m$ and $77.5{\mu}m$. These values were smaller than that of $25^{\circ}C$ air. There were significant differences in the occlusal discrepancies between $25^{\circ}C$ air and water conditions of $50^{\circ}C$ water (${\alpha}=0.05$) but. no significant difference in marginal discrepancies. There was no significant difference in the interaction between time and temperature. 4 minutes waiting time & $50^{\circ}C$ water polymerizing condition produces the best fit at the margin of the provisional crown.

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.27-37
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• 2006

Although the main purpose of periodontal treatment to regenerate is the complete regeneration of periodontal tissue due to periodontal disease, most of the treatment cannot meet such purpose because healing by long epithelial junction. Therefore, diverse materials of resorbable and non-resorbable have been used to regenerate the periodontal tissue. Due to high risk of exposure and necessity of secondary surgical procedure when using non-resorbable membrane, guided tissue regeneration using the resorbable membrane has gain popularity, recently. However, present resorbable membrane has the disadvantage of not having sufficient time to regenerate date to the difference of resorption rate according to surgical site. Meanwhile, other than the structure stability and facile manipulation, acellular dermal matrix has been reported to be a possible scaffold for cellular proliferation due to rapid revascularization and favorable physical properties for cellular attachment and proliferation. The purpose of this study is to estimate the influence of acellular dermal matrix on periodontal ligament, cementum and alveolar bone when acellular dermal matrix is implanted to 1-wall alveolar bone defect. 4 dogs of 12 to 16 month old irrelevant to sex , which below 15Kg of body weight, has been used in this study. ADM has been used for the material of guided tissue regeneration. The 3rd premolar of the lower jaw was extracted bilaterally and awaited for self-healing. subsequently buccal and lingual flap was elevated to form one wall intrabony defect with the depth and width of 4mm on the distal surface of 2nd premolar and the mesial surface of 4th premolar. After the removal of periodontal ligament by root planing. notch was formed on the basal position. Following the root surface treatment, while the control group had the flap sutured without any treatment on surgically induced intrabony defect. Following the root surface treatment, the flap of intrabony defect was sutured with the ADM inserted while the control group sutured without any insertion. The histologic specimen was observed after 4 and 8 weeks of treatment. The control group was partially regenerated by periodontal ligament, new cementum and new alveolar bone. the level of regeneration is not reached on the previous formed notch. but, experimental group was fully regenerated by functionally oriented periodontal ligament fiber. new cementum and new alveolar bone. In conclusion, we think that ADM seems to be used by scaffold for periodontal ligament cells and the matrix is expected to use on guided tissue regeneration.