• Journal of Animal Science and Technology
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• v.53 no.3
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• pp.227-235
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• 2011

A total of 96 crossbred weanling barrows aged 21 days were randomly allocated to 32 pens of a new nursery to investigate the effects of antibiotics, phytogenics, and probiotics on intestinal growth and development. The animals were fed a set of three-phase basal diets containing 0.3% zinc oxide (CON) or the basal diets supplemented with 353 ppm of a combination of tiamulin, neomycin, chlortetracycline, and oxytetracycline (ANTI), 75 ppm triterpenoid saponin plus 150 ppm mixed saccharides (HERB; Sacchapin$^{(R)}$), or $1{\times}10^7$ brewer's yeasts plus $8{\times}10^7$ spores of each of Bacillus licheniformis and Bacillus subtilis per kilogram feed (PROBIO; Yeasture Plus 2B$^{(R)}$) for five weeks. Thirty-two pigs representing as many pens were slaughtered at the end of the feeding trial, after which morphological measures and digestive enzyme activities of intestinal mucosa were determined. Weight gain and gain:feed of the pigs were not affected by the dietary treatments (TRT) during the overall feeding trial. Total intestinal length was greater in PROBIO than in ANTI (P<0.05). Wet mucosa weight of the duodenum was not affected by TRT. However, jejunal mucosa weight was greater in PROBIO than in any other group sum of mucosa weights of the duodenum and jejunum was greater (P<0.05) in PROBIO than in ANTI and HERB. The height and width of duodenal villus were not affected by TRT, but crypt depth decreased (P<0.05) in response to HERB and PROBIO vs CON. Specific activities of alkaline phosphatase, sucrase, maltase, lactase, and leucine aminopeptidase in the duodenum and jejunum were not changed by TRT. In conclusion, results suggest that the present dietary treatments have no effects on growth performance of weanling pigs and that of PROBIO enhances intestinal growth and development under a clean experimental setting.

• Korean Journal of Veterinary Research
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• v.32 no.3
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• pp.435-450
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• 1992

To evaluate the fertilizing capacity of domestic animal spermatozoa by hamster test, semen were collected from 15 boars(Duroc, Landrace, and Yorkshire) and 2 mixed dogs which had been proved to be fertile in the past then, the semen were preserved in BWW medium at $4^{\circ}C$ or $18^{\circ}C$ for about 20 hours and coincubated with zona-free hamster ova for 5 hours. The ova were stained by lacmoid and examined under phase contrast microscope to investigate the rates of sperm binding to the ova, penetration and formation of a male pronucleus, and the numbers of both bound and penetrated sperm per ovum. Both the semen preserved at $18^{\circ}C$ for about 20 hours and that treated by swim up procedure showed considerably higher rates of sperm binding and penetration as well as higher number of penetrated sperm than that preserved at $4^{\circ}C$ for about 20 hours, respectively(p<0.01). Motility of boar sperm at insemination was from 40 to 90% and no difference in hamster test was obtained according to different degree of sperm motility. Abnormality in morphology of boar sperm at insemination was from 6 to 45% and no difference in hamster test was obtained according to different degree of sperm abnormality. The sperm concentrations of $7{\times}10^7$ and $7{\times}10^6$ showed considerably higher rates of sperm binding and penetration as well as higher number of bound sperm than that of $7{\times}10^4$ (p<0.01) along with the same higher results than that of $7{\times}10^5$(0<0.05), respectively. Boar sperm showed considerably higher rates of sperm binding and penetration as well as higher numbers of both bound and penetrated sperm than dog sperm, when both semen were treated by BWW＋heparin medium and swim up procedure, respectively. These results indicated that fertile boar sperm showed considerably lower rates in the results of hamster test, when preserved at $4^{\circ}C$ for about 20 hours and in lower concentration of sperm than when preserved at $18^{\circ}C$ for about 20 hours and in higher concentration of sperm, respectively, and at the same time considerably higher results than fertile dog sperm, consequently to prove that hamster test would be of great value in assaying the fertilizing capacity of boar sperm.

• Membrane Journal
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• v.21 no.2
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• pp.177-192
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• 2011

Hollow fiber membrane using CTA polymers were prepared by the phase separation method for the separation and purification of biogas and the hollow fiber gas separation membrane modules with the effective surface area of 0.17 $m^2$ were prepared. The pure gas permeation properties of membrane modules for methane, oxygen and carbon dioxide were measured. The permeance of $CO_2$ and $CH_4$were 0.46 GPU and 18.52 GPU, respectively, therefore, the high $CO_2$/$CH_4$ selectivity of 40.4 was obtained. The separation and purification test for 4 different simulated mixed gases were carried out after the pure gas test and the gas concentration and flux of the permeate at the various stage-cut were measured from the 1 stage, 2 stage, and 3 stage cascade of membrane modules. In the 1 stage test, the concentration of $CH_4$ increased as the increase of the stage-cut, while the $CH_4$ recovery efficiency ratio decreased. In the 2 stage test, the $CH_4$ recovery efficiency ratio increased compared to the 1 stage. The 3 stage test was employed to reduce the loss of $CH_4$ in biogas and the result showed less than 5% of $CH_4$ recovery loss.

• Membrane Journal
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• v.17 no.3
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• pp.269-275
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• 2007

Sodium type faujasite(FAU) zeolite membranes with a thickness of 5${\mu}m$ and a Si/Al molar ratio of 1.5 were prepared by the secondary growth process. The $CO_2/N_2$ separation in the vacuum mode was investigated at $30^{\circ}C$ for an equimolar $CO_2-N_2$ mixed gas before and after embedding 13X zeolite beads in the permeate side. The embedded 13X zeolite beads improved both $CO_2$ permeance and $CO_2/N_2$ separation factor, simultaneously. The phenomenon was explained by an increment in the $CO_2$ desorption rate at the FAU zeolite/$\alpha-Al_2O_3$ phase boundary due to an enhanced $CO_2$ escaping through the pore channels of the $\alpha-Al_2O_3$ support layer. In the present paper, it will be emphasized that a hybridization of a membrane with an adsorbent can provide a key to break through the trade-off between permeance and separation factor, generally shown in a membrane separation.

• Journal of the Korean Ceramic Society
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• v.29 no.5
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• pp.347-356
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• 1992

Various kaolin samples with different alumina content were prepared from calcined admixture of kaolin and ammonium sulfate by varying the treatment time in sulfuric acid. Samples were nitridated under N2 or N2-H2 atmosphere with changing the amount of added carbon, the reaction time and temperature. As the alumina content lowered, the size of kaolin particles decreased and the specific surface area increased. XRD analysis indicated that ${\alpha}$-quartz remained by decomposition of halloysite and meta-halloysite. Experimental results of nitridation behavior are summerized as follows; 1) Nitridation under N2 atmosphere. With the increase of C/SiO2 ratio and with the decrease of Al2O3 content, disappearance of XRD pattern peaks of mullite, ${\alpha}$-quartz and ${\alpha}$-Al2O3 were accelerated at 1300$^{\circ}C$. SiC was the main phase in the reaction product of acid-treated kaolin samples nitridated at 1300$^{\circ}C$ for 10 hours regardless of C/SiO2 ratio. But the XRD peak intensities of ${\beta}$-Si3N4, ${\beta}$-sialon and SiC did not show much difference when untreated raw kaolin was fired at the same condition. When the ratio of C/SiO2 was 3.5, ${\beta}$-sialon and ${\beta}$-Si3N4 existed in the reaction product of about 22% alumina containing kaolin sample fired at 1350$^{\circ}C$ for 7 hours. Only ${\beta}$-sialon existed in the same sample fired at 1400$^{\circ}C$ for 10 hours. ${\beta}$-sialon was obtained from all of the acid-treated kaolin samples fired at 1400$^{\circ}C$ for 40 hours, but AlN and SiC remained in the untreated kaolin sample. Z value of the ${\beta}$-sialon obtained from the 22% alumina containing kaolin sample fired at 1400$^{\circ}C$ for 40 hours was about 1.3(XRD) and 1.5(EDS). 2) Nitridation under 80N2+2OH2 mixed gas atmosphere with the C/SiO2 ratio of 1 Mullite was not found, but ${\alpha}$-Si3N4, and ${\beta}$-sialon were present in the reaction product of about 22% alumina containing kaolin sample fired at 1300$^{\circ}C$ for 10 hours. When untreated kaolin sample was nitridated at the same condition, mullite remained. AlN and SiC were not found in the reaction product of about 22% alumina containing kaolin sample fired at 1350$^{\circ}C$ for 5 hours. On the other hand, AlN and SiC remained in the product of untreated kaolin fired at the same condition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.11
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• pp.707-711
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• 2014

The $0.99Bi_{0.5}(Na_{0.78}K_{0.22})_{0.5}TiO_3-0.01LaAlO_3$, $0.01LaMnO_3$ or $0.01LaFeO_3$ (0.99BNKT-0.01LA, 0.01LM or 0.01LF) ceramics were prepared by a conventional mixed mothod. The structure and morphology of the lead free ceramics were characterized by XRD (X-ray diffraction) and FE-SEM (field emission scanning electron microscopy). XRD results indicated that the BNKT ceramics modified by LA, LM or LF induced a transition from a ferroelectric tetragonal to a non-polar pseudo-cubic phase, leading to decrease in the remnant polarization ($P_r$) and coercive field ($E_c$) in the P-E hysterisis loops. The effects of the BNKT ceramics modified by La-based $ABO_3$ pervskite structure on the electric-field induced strain were investigated, and the largest normalized unipolar strain ($S_{max}/E_{max}$) was found in BNKT-0.01LF ceramic.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.260-260
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• 2013

Multiferroic materials have attracted much attention due to their fascinating fundamental physical properties and technological applications in magnetic/ferroelectric data-storage systems, quantum electromagnets, spintronics, and sensor devices. Among single-phase multiferroic materials, $BiFeO_3 $ is a typical multiferroic material with a room temperature magnetoelectric coupling in view of high magnetic-and ferroelectric-ordering temperatures (Neel temperature $T_N$~647 K and Curie temperature $T_C$~1,103 K). Rare-earth ion substitution at the Bi sties is very interesting, which induces suppressed volatility of Bi ion and improved ferroelectric properties. At the same time, Fe-site substitution with magnetic ions is also attracting, and the enhanced ferromagnetism was reported. In this study, $Bi_{1-x}Dy_xFe_{0.95}Co_{0.05}O_3$ (x=0, 0.05 and 0.1) bulk ceramic compounds were prepared by solid-state reaction and rapid sintering. High-purity $Bi_2O_3$, $Dy_2O_3$, $Fe_2O_3$ and $Co_3O_4$ powders with the stoichiometric proportions were mixed, and calcined at $500^{\circ}C$ or 24 h to produce $Bi_{1-x}Dy_xFe_{0.95}Co_{0.05}O_3$. The samples were immediately put into an oven, which was heated up to $800^{\circ}C$ nd sintered in air for 30 min. The crystalline structure of samples was investigated at room temperature by using a Rigaku Miniflex powder diffractometer. The field-dependent magnetization measurements were performed with a vibrating-sample magnetometer. The electric polarization was measured at room temperature by using a standard ferroelectric tester (RT66B, Radiant Technologies).

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2001.11a
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• pp.7-7
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• 2001

The increasing interest in light weight materials coupled to the need for cost -effective processing have combined to create a significant opportunity for aluminum P/M. particularly in the automotive industry in order to reduce fuel emissions and improve fuel economy at affordable prices. Additional potential markets for Al PIM parts include hand tools. Where moving parts against gravity represents a challenge; and office machinery, where reciprocating forces are important. Aluminum PIM adds light weight, high compressibility. low sintering temperatures. easy machinability and good corrosion resistance to all advantages of conventional iron bm;ed P/rv1. Current commercial alloys are pre-mixed of either the AI-Si-Mg or AL-Cu-Mg-Si type and contain 1.5% ethylene bis-stearamide as an internal lubricant. The powder is compacted in closed dies at pressure of 200-500Mpa and sintered in nitrogen at temperatures between $580~630^{\circ}C$ in continuous muffle furnace. For some applications no further processing is required. although most applications require one or more secondary operations such as sizing and finishing. These sccondary operations improve the dimension. properties or appearance of the finished part. Aluminum is often considered difficult to sinter because of the presence of a stable surface oxide film. Removal of the oxide in iron and copper based is usually achieved through the use of reducing atmospheres. such as hydrogen or dissociated ammonia. In aluminum. this occurs in the solid st,lte through the partial reduction of the aluminum by magncsium to form spinel. This exposcs the underlying metal and facilitates sintering. It has recently been shown that < 0.2% Mg is all that is required. It is noteworthy that most aluminum pre-mixes contain at least 0.5% Mg. The sintering of aluminum alloys can be further enhanced by selective microalloying. Just 100ppm pf tin chnnges the liquid phase sintering kinetics of the 2xxx alloys to produce a tensile strength of 375Mpa. an increilse of nearly 20% over the unmodified alloy. The ductility is unnffected. A similar but different effect occurs by the addition of 100 ppm of Pb to 7xxx alloys. The lend changes the wetting characteristics of the sintering liquid which serves to increase the tensile strength to 440 Mpa. a 40% increase over unmodified aIloys. Current research is predominantly aimed at the development of metal matrix composites. which have a high specific modulus. good wear resistance and a tailorable coefficient of thermal expnnsion. By controlling particle clustering and by engineering the ceramic/matrix interface in order to enhance sintering. very attractive properties can be achicved in the ns-sintered state. I\t an ils-sintered density ilpproaching 99%. these new experimental alloys hnve a modulus of 130 Gpa and an ultimate tensile strength of 212 Mpa in the T4 temper. In contest. unreinforcecl aluminum has a modulus of just 70 Gpa.

• Journal of Pharmaceutical Investigation
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• v.27 no.4
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• pp.287-293
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• 1997

To make a stable o/w emulsion, the effects of egg lecithin as an emulsifier and polyvinylpyrrolidone (PVP) as an auxiliary emulsifier on the physical stability of emulsion were investigated. The oil-in-water emulsion system was manufactured by microfluidizer and evaluated the physical stability. Average particle size and size distribution of emulsion was measured by dynamic light scattering analyzer and interfacial tension was measured. From the interfacial tension tested, critical micelle concentration of the egg lecithin was 0.1 %w/v and optimal concentration for the preparation of emulsion was 1.0 %w/v. The mean particle size was about $0.2\;{\mu}m$ which was suitable for injections. The short-term accelerated stability studies were conducted by centrifugation, freeze-thaw method and shaking of the emulsion samples. The addition of PVP was caused the reduction in the particle size and improved the physical stability of emulsion. These results suggested that a mixed interfacial film comprising the egg lecithin and PVP was formed at the o/w interface and it was effective in preventing phase separation under thermic or mechanical stress. We used antineoplaston A10 (A10) as a model drug which is peptide and amino acid derivative having a action to the living organism against the development of neoplastic growth by a nonimmunological progress. It has a poor solubility in water and there may be a difficulty in formulation of A10. Emulsion formulation study about A10 was performed. Solubility of A10 in emulsion was about five times as high as that in water. From the results of solubility and partition coefficient, almost A10 molecules in o/w emulsion exist in the interface between oil and water.

• Analytical Science and Technology
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• v.16 no.2
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• pp.102-109
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• 2003

Microwave digestion and solid-state extraction were studied for determination of trace aluminum{Al(III)} in human urine samples. A mixed acid of nitric acid and hydrogen peroxide was added to urine samples, organic materials were destructed in a home microwave oven and dried in a drying oven. The dried residues were dissolved in a sulfuric acid solution. The solution was eluted through a XAD-4 resin column adsorbed with 8-hydroxyquinoline(Oxine, HQ). Al(III)-8-hydroxyquinolinate complex was formed in the column and eluted with 0.5 M nitric acid solution. The Al(III) eluted was determined by graphite atomic absorption spectrophotometry. Various experimental conditions of followings were investigated for the optimization : the type of acid to dissolve the residues, the amount of HQ adsorbed on the resin, the pH of sample solutions, the type and concentration of acid to elute the complex from column and so on. The contents of Al(III) in real samples were determinated by a calibration curve method. The recovery in standard spiked samples was 94~101% and the detection limit of this procedure was 0.05 ng/mL.