• Resources Recycling
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• v.27 no.5
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• pp.61-68
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• 2018

The aluminum dross is oxide generated on the surface of the molten metal during the aluminum melting process and it is divided into white dross and black dross according to presence of the Salt flux. White dross has high metal content and is recycled via the melting process. Black dross is largely berried, because the it has a low metal content and difficulty in separating the components. Black dross contains a salt components such as NaCl and KCl, and inorganic materials such as $Al_2O_3$ and MgO, and it is necessary to study the technology to recover and recycle such valuable resources. In this study, a process for recycling aluminum black dross was proposed. The inorganic and soluble substances present in the black dross were separated through crushing-dissolution-solid/liquid separation-decompression evaporating. By controlling the ratio of water and black dross, the recovery condition of the separated product was optimized and we confirmed the highest Salt flux recovery efficiency 91 wt.% at black dross:water ratio 1:9. Finally, Through the synthesis of zeolite using recovered ceramic material, the materialization possibility of black dross was confirmed.

• Journal of Astronomy and Space Sciences
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• v.19 no.3
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• pp.187-196
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• 2002

We performed CCD photometric observations of the eclipsing binary Y Cam with a pulsating component, for 16 nights from November 2000 to May 2001 using a V filter attached to the 61-cm reflector at Sobaeksan Optical Astronomy Observatory. Our V light curve and Broglia & Marin's (1974) BV ones were analyzed with Mode 2 for a detached Roche model as well as Model 5 for a semi-detached one in the Wilson-Devinney code. From the analysis, we found the following results: 1) It is hardly discernible from only light curve synthesis which model between the detached and semi-detached ones is a real Roche model of Y Cam. 2) There exist the third light of about 2% and 3% in B and V light curves of Y Cam, respectively. 3) The light curve solution is immune from the light variation due to the pulsation of the primary component of Y cam. However, the detached model rather than the semi-detached one has slightly better fitted to the observations which were get rid of the pulsation effect. 4) The absolute dimensions of Y Cam were calculated for two Roche models.

• Food Science and Preservation
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• v.24 no.5
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• pp.688-696
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• 2017

In this study, the physicochemical properties and anti-wrinkle effect of polysaccharides with different molecular weights from Gloiopeltis furcata were investigated. Crude polysaccharides were isolated by viscozyme treatment followed by ethanol precipitation and lyophilization. Crude polysaccharides were hydrolyzed by acid (0.1 N HCl) and the molecular weight fractions were generated by centrifugal filter (<10 kDa, 10 to 100 kDa, and 100 kDa>). The yield of polysaccharides with different molecular weight fractions was 8.4-39.6%. The major constituents in molecular weight fractions were total sugar (81.37-85.82%), uronic acid (27.89-32.85 g/100 g), sulfate (33.38-39.04%), and protein (0.35-3.16%) The L, a, and b value of the 100 kDa group were decreased, but viscosity increased. The oxygen radical absorbance capacity of the 100 kDa group at $180.07{\mu}M$ was the highest among groups. The protective effects of 100 kDa group at 0.5 and $5{\mu}g/mL$ against $H_2O_2$-induced cytotoxicity in L132 cell were 87.34% and 103.85%, respectively. The matrix metalloproteinase-1 activity of 100 kDa group decreased in a dose-dependent manner. The pro-collagen synthesis activity of 100 kDa group at $0.05-0.5{\mu}g/mL$ was 64.91-77.80%. The polysaccharides with different molecular weights from Gloiopeltis furcata investigated herein are useful as a potential candidate for cosmedical materials.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.527-534
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• 2006

The purpose of this study is the development of more effective filter-type polymer adsorbent for removal of anionic pollutants from wastewater. In order to synthesize the polymer adsorbent that possesses anionic exchangeable function, carboxyl(-COOH) group of PP-g-AA nonwoven fabric was converted into amine($-NH_2$) group by the chemical modification using diethylene triamine(DETA). FT-IR data indicate that amine group was introduced into PP-g-AA through amidation of grafted acrylic acid by reaction with DETA. The degree of amination increased with increase in the reaction time and temperature of the chemical modification process, and was significantly improved by the pre-swelling treatment of PP-g-AA with solvent and addition of metal chlorides as a catalyst in following order as $NH_4OH>MeOH{\geq}HCl{\geq}H_2O\;and\;AlCl_3>FeCl_3{\geq}SnCl_2{\gg}ZnCl_2{\geq}FeCl_2$, respectively. However, the addition of catalyst limited the reusability of DETA, hence was less useful from the viewpoint of cost effectiveness and waste management. The anion exchange capacity of the aminated PP-g-AA(PP-g-AA-Am) increased with increase in the degree of amination, but it reached maximum value at the degree of amination as about $50{\sim}60%$. The anion exchange capacity of PP-g-AA-Am was higher than those of commercial anion resins.

• Clean Technology
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• v.18 no.1
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• pp.63-68
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• 2012

In this study, aluminum hydroxide ($Al(OH)_3$) was synthesized by Bayer process and sodium contained in $Al(OH)_3$ was removed with the acid solution such as HCl and acetic acid for the synthesis of high purity alumina. The bauxite produced in Queensland of Australia was used for the production of alumina by Bayer, and was crushed to a particle size of below 10 um by attrition mill. The crushed bauxite was treated in sodium hydroxide solution of 5 N for the elution of aluminum component. The elution of aluminum from bauxite was carried out at $140^{\circ}C$ and 3.4 atm in autoclave. The sample solution was separated to the red mud and liquid solution by filter paper. The elution of aluminum from bauxite was confirmed with changing a structure and aluminum content in both bauxite and red mud analyzed by XRD and EDX. Aluminum contained in the separated solution was crystallized to $Al(OH)_3$ with the addition of aluminum hydroxide used as the seed material. $Al(OH)_3$ powder obtained during the crystallization process was purified by several times washing with distillated water. It was also confirmed that the sodium remained in $Al(OH)_3$ powder is removed with acid solution. The purity of $Al(OH)_3$ powder produced in this study was 99.3% and the content of sodium was reduced to approximately 0.009% after the acid treatment.

• The Journal of the Acoustical Society of Korea
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• v.29 no.1
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• pp.48-55
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• 2010

It has a falling off in speech quality, especially when consecutive packet loss occurs, even if a vocoder implemented in the packet network has its own packet loss concealment (PLC) algorithm. PLC algorithm is divided into transmitter and receiver algorithm. Algorithm in the transmitter gives superior quality by additional information. however it is impossible to provide mutual compatibility and it occurs extra delay and transmission rate. The method applied in the receiver does not require additional delay. However, it sets limits to improve the speech quality. In this paper, we propose a new method that puts extra information for PLC in a part of Extension Header Data which is not used in RTP Header. It can solve the problem and obtain enhanced speech quality. There is no extra delay occurred by the proposed algorithm because there is a jitter buffer to adjust network delay in a receiver. Extra information, 16 bits each frame for G.729 PLC, is allocated for MA filter index in LP synthesis, excitation signal, excitation signal gain and residual gain reconstruction. It is because a transmitter sends speech data each 20 ms when it transfers RTP payload. As a result, the proposed method shows superior performance about 13.5%.

• Tuberculosis and Respiratory Diseases
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• v.49 no.6
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• pp.703-714
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• 2000

Background : Surfactant protein A (SP-A) is important in the regulation of surfactant secretion, synthesis and recycling. SP-A has important roles in regulating surfactant metabolism as well as in determining surfactant's physical properties. Since systemic sepsis is one of the common causes of acute respiratory distress syndrome (ARDS) and abnormalities in surfactant function have been described in ARDS, the authors investigated the effects of endotoxemia on the accumulation of mRNA encoding SP-A and SP-A protein content. Methods : Adult rats were given various doses of intraperitoneal endotoxin from Salmonella enteritidis and sacrificed at different times. SP-A mRNA was measured by filter hybridization method. Lung SP-A protein content was determined by double sandwich ELISA assay using a polyclonal antiserum raised in rabbits against purified rat SP-A. Results : 1) The accumulation of SP-A mRNA in the endotoxin treated group 24 hours after 2mg/kg and 5mg/kg endotoxin treatments was significantly increased 50.9% and 27.3%, respectively, compared to the control group (P<0.001, P<0.025). 2) The accumulation of SP-A mRNA 24 hours in the 5mg/kg endotoxin treated group was significantly increased by 26.5% compared to the control group (P<0.01). 3) Total amount of lung SP-A was not altered at 24 hours by various doses of treatment. Total lung SP-A content 144 hours after endotoxin administration was significantly decreased by 51.4% compared to the control group (P<0.01). Conclusions : The specific regulation of SP-A by various time course in vivo is evident. The late decline in SP-A protein content was unexpected and suggests that SP-A may be differentially regulated during lung inflammation. The functional significance of these alterations remains to be clarified.

• Clean Technology
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• v.11 no.3
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• pp.123-128
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• 2005

Among various metal oxides semiconductors, $TiO_2$ is the most studied semiconductor for environmental clean-up applications due to its unique ability in photocatalyzing various organic contaminants, its chemical inertness, and nontoxicity. $TiO_2$, however, has a few drawbacks to be solved such as reactivity mainly working under ultraviolet irradiation (${\lambda}$ < 387 nm) and electron - hole recombination on $TiO_2$. In this study, to extend the absorption range of $TiO_2$ into the visible range and enhance electron - hole separation, we synthesized platinum (Pt) deposited $C-TiO_2$. The presence of Pt as an electron sink has been known to snhance the separation of photogenerated electron-hole pairs and induce the thermal decomposition. The characterization of as-synthesized $Pt-C-TiO_2$ was performed by Transmission Electron Microscopic (TEM), the Brunuer-Emmett-Teller (BET) method, X-ray Diffractometer (XRD), UV-vis spectrometer (UV-DRS), and X-ray Photoelectron Spectroscopy (XPS). In order to estimate the photocatalytic activity of the synthesized materials, the photoelectron Spectroscopy (XPS). In order to estimate the photocatalytic activity of the synthesized materials, the photodegradation experiment of an azo dye (Acid Red 44; $C_{10}H_7N=NC_{10}H_3(SO_3Na)_2OH$)was carried out by using an Xe arc lamp (300 W, Oriel). A 420 nm cut-off filter was used for visible light irradiation. From the results, Pt-deposited $C-TiO_2$ showed a far superior phothdegradation activity to Degussa P25, the commercial product under the irradiation of visible light and enhanced photocatalytic activity of visible-working $C-TiO_2$. This is a useful result into the application for the purification system of dye wastewater using visible energy of sun light.

• Tuberculosis and Respiratory Diseases
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• v.55 no.3
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• pp.257-266
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• 2003

Background : The surfactant protein A(SP-A) is important in the regulation of surfactant secretion, synthesis and recycling. Since the acute respiratory distress syndrome(ARDS) is usually viewed as the functional and morphological expression of a similar underlying lung injury casued by a variety of insults and since abnormalities in surfactant function have been described in ARDS, the authors investigated the different effects of endotoxin and thiourea on the accumulation of mRNA encoding SP-A. Methods : Sprague-Dawley rats were given 5 mg/kg intraperitoneal endotoxin from Salmonella enteritidis and 3.5 mg/kg intraperitoneal thiourea and sacrified at different time periods. Results : 1) SP-A mRNA was significantly increased 67.0% in 6 hours and 73.4% in 24 hours after 5 mg/kg endotoxin treatment respectively(P<0.005, P<0.005). 2) SP-A mRNA significantly decreased 32.9% in 24 hours after 3.5 mg/kg thiourea treatment(P<0.05). Conclusions : These results indicate that the differential regulation of surfactant protein A in vivo is evident and suggest that surfactant protein A might be differentially regulated during different kind of insults of lung injury at different time periods without altering lung wet to dry ratios.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.28 no.1
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• pp.80-98
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• 2002

Taxus cuspidata Sieb selected cultivation as drug, food and decorative plant in Kyong-gi province in Korea. As a manufacturing method, there were extracted from 250g of dried-leaf and 300g of dried-stem with each 200g of BG, PG and water (to 100) mixing for 72 hour at 50$\pm$5$\^{C}$ and then they were filtered by 400-mesh filter. Appearance of extract of leaves was slight brown, pH=5.3$\pm$0.5, gravity was 1.012$\pm$0.05, and a reflective index was 1.375$\pm$0.05. And appearance of extract of stems was slightly dark brown, pH=5.4$\pm$0.5, gravity was 1.016$\pm$0.05, and a reflective index was 1.358$\pm$0.05. It was extracted oil from Taxus seed. Gravity was 0.922$\pm$0.05 and it should be obtained the 27.0$\pm$0.5% of yield. The molecular weight of polysaccharide was about 50,000 to 300,000 dalton and contained 5.0$\pm$1.2% of yield from Taxus fruit. The determinations of total polyphenols in measuring spectropotometer got 0.563% in leaves, and 0.325% in stems, whereas the quantitives of total tannins got 0.054% and 0.037%, respectively. As the effects in Cosmetics by DPPH-method, the antioxidative activities were very strong that the inhibitory ratio showed 75% in leaves and 64% in stems compared with 52% in greentea extract. These are more effective than other plant extracts. The increasing ratio of collagen synthesis rate on the activating fibroblast for extracts of Taxus cuspidata Sieb showed 54.16% (stems) and 33.18% (leaves), To improve the skin elasticity, PPE(porcine pancreatic elastase)-inhibitory activities were strongly effective as 13,7% (stems), 23.5% (leaves) and 66%(seed). Anti-inflammatory acitvity of seed oil was very the above 41% stronger than SG was 24% of anti-Inflammatory as a control sample.