• Animal Systematics, Evolution and Diversity
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• v.28 no.1
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• pp.20-28
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• 2012

Two urostylid ciliates, Anteholosticha pulchra (Kahl, 1932) Berger, 2003 and Metaurostylopsis struederkypkeae Shao et al., 2008, new to Korea, were collected from the Yellow Sea and the East Sea, Korea, respectively. They were identified based on live observation and protargol impregnation. Taxonomical characters of A. pulchra are as follows: $190-300{\times}30-55\;{\mu}m$ size in vivo; contractile vacuole located on the left side of the posterior 1/4 of the cell; spherical-reddish granules at cirral bases and around dorsal bristles, somewhat sparsely distributed throughout the cell surface; four frontal and two frontoterminal cirri; four dorsal kineties; caudal cirri absent. Metaurostylopsis struederkypkeae is characterized as follows: $80-110{\times}40-50\;{\mu}m$ size in vivo; caudal cirri absent; two types of cortical granules: type 1, yellow-green arranged along the ventral cirral rows and dorsal kineties; type 2, small and reddish, with an irregular arrangement; four frontal, four to eight frontoterminal, and two to six transverse cirri; five to seven left and three to five right marginal rows. Sequences of small subunit ribosomal DNA were determined from both species, and pairwise distances with their relatives were analyzed.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.443-446
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• 2006

Carbon-supported Platinum (Pt) is the potential electro-catalyst material for anodic and cathodic reactions in fuel cell. Catalytic activity of the metal strongly depends on the particle shape, size and distribution of the metal in the porous supportive network. Conventional preparation techniques based on wet impregnation and chemical reduction of the metal precursors often do not provide adequate control of particle size and shape. We have proposed a novel route for preparing nano sized Pt colloidal particles in solution by oxidation of ethylene glycol. These Pt nano particles were deposited on large surface area carbon support. The process of nano Pt colloid formation involves the oxidation of solvent ethylene glycol to mainly glycolic acid and the presence of its anion glycolate depends on the solution pH. In the process of colloidal Pt formation glycolate actsas stabilizer for the Pt colloidal particle and prevents the agglomeration of colloidal Pt particles. These mono disperse Pt particles in carbon support are found uniformly distributed in nearly spherical shape and the size distribution was narrow for both supported and unsupported metals. The average diameter of the Pt nano particle was controlled in the range off to 3 nm by optimizing reaction parameters. Transmission electron microscopy, CV and RRDE experiments were used to compliment the results.

• Journal of the Korean Society of Safety
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• v.19 no.4 s.68
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• pp.74-79
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• 2004

[ $CO_3O_4/{\gamma}-Al_2O_3$ ] catalysts were reported high activity on the low temperature CO oxidation. The effects of the calcination temperature, the loaded amount of cobalt and the oxygen concentration on the characteristics of CO oxidation have been investigated for a emergency escape mask cartridge. $Co(NO_3)_2\cdot6H_2O$ was used as cobalt precursor and the catalysts were prepared by incipient wetness impregnation. TGA shows that enough calcination is accomplished at $450^{\circ}C$ and cobalt phase is $Co_3O_4$ after calcination in the temperature range of $300\ ~500^{\circ}C$. The specific surface area and pore volume of catalysts are decreased with increasing of loaded amount of cobalt. And with the increase of loaded amount of cobalt and the oxygen concentration, the catalytic activity is increased.

• Journal of the Korean Applied Science and Technology
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• v.19 no.3
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• pp.213-221
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• 2002

Activated carbons with high surface area of 2,600 $m^{2}/g$ and high pore volume of 1.2 cc/g could be prepared by KOH activation of rice hulls at a KOH:char ratio of 4:1 and $850^{\circ}C$. In order to increase the adsorption capacity of hydrogen sulfide, which is one of the major malodorous component in the waste water treatment process, various contents of $Na_{2}CO_{3}$ and $KIO_{3}$ were impregnated to the rice-hull activated carbon. The impregnated activated carbon with 5 wt.% of $Na_{2}CO_{3}$ showed improved $H_{2}S$ adsorption capacity of 75 mg/g which is twice of that for the activated carbon without impregnation and the impregnated activated carbon with 2.4 wt.% of $KIO_{3}$ showed even higher $H_{2}S$ adsorption capacity of 97 mg/g. The improvement of $H_{2}S$ adsorption capacity by the introduction of those chemicals could be due to the $H_{2}S$ oxidation and chemical reaction with impregnated materials in addition to the physical adsorption of activated carbon.

• Environmental Engineering Research
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• v.10 no.5
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• pp.239-246
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• 2005

The effect of Pt addition over $V_2O_5-WO_3/TiO_2$ catalyst supported on PRO-66 was investigated for NO reduction in order to develop the catalytic filter working at low temperature. Catalytic filters, $Pt-V_2O_5-WO_3/TiO_2/PRD$, were prepared by co-impregnation of Pt, V, and W precursors on $TiO_2$-coated ceramic filter named PRD (PRD-66). Titania was coated onto the pore surface of the ceramic filter using a vacuum aided-dip coating method. The Pt-loaded catalytic filter shifted the optimum working temperature from $260-320^{\circ}C$(for the catalytic filter without Pt addition) to $190-240^{\circ}C$, reducing 700 ppm NO to achieve the $N_x$ slip concentration($N_x\;=\;NO+N_2O+NO_2+NH_3$) less than 20 ppm at the face velocity of 2 cm/s. $Pt-V_2O_5-WO_3/TiO_2$ supported on PRD showed the similar catalytic activity for NO reduction with that supported on SiC filter as reported in a previous study, which implies the ceramic filter itself has no considerable interaction for the catalytic activity.

• Journal of the Korean Ceramic Society
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• v.35 no.7
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• pp.740-748
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• 1998

The inertia friction properties of C/C composites manufactured by the processes of pressure and at-mospheric carbonizaton with a commerciallized and two kinds of modified coal-tar pitch as a matrix pre-cursor were investigated. The modifications of a pitch such as the introduction of mesophase and the ad-dition of sulphur into a raw pitch were not effective for a impregnation efficiency conducted in a vacuum and at the same time in a pressure of 5kg/cm2 due to the increase of the pitch viscosity. There was not a difference in the densification increment between the pitch modifications however it was revealed that a pressure carbonization was more advantageous than an atmospheric in the densification and the formation of anisotropic carbon matrix. The friction and wear propertis of C/C having higher degree of matrix cry-stallization higher density and hardness of friction surface showed superiority. As the braking energy was increased the friction coefficients were decreased and reached almost same level at the high kinetic energy of 99.6kJ. The wear trends at 99.6kJ were different from the behaviors of friction ceofficient under the same energy in which an oxidation wear is being considered along with a mechnical wear although the wear rates were almost similar to the friction coefficient at the low energy.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.657-664
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• 2004

Titanium sulfate supported on $TiO_2$was prepared by impregnation of powdered $TiO_2$with an aqueous solution of titanium sulfate followed by calcining in air at high temperature. For Ti$(SO_4)_2/TiO_2$ samples calcined at 300 $^{\circ}C$, no diffraction lines of titanium sulfate are observed at $Ti(SO_4)_2$loading up to 30 wt%, indicating good dispersion of $Ti(SO_4)_2$ on the surface of $TiO_2$. The acidity of the catalysts increased in proportion to the titanium sulfate content up to 20 wt% of $Ti(SO_4)_2$. 20 wt% $Ti(SO_4)_2/TiO_2$ calcined at 300 $^{\circ}C$ exhibited maximum catalytic activities for 2-propanol dehydration and cumene dealkylation. The catalytic activities for these reactions, were correlated with the acidity of catalysts measured by ammonia chemisorption method.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.634-638
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• 2004

Titanium silicalite-1 (TS-1) molecular sieve was produced by microwave heating of amorphous titanium-containing solid precursors after impregnation with aqueous TPAOH solution. $SiO_2-TiO_2$ xerogel, sub-micron sized $SiO_2-TiO_2$ prepared by thermal plasma process, and Ti-containing mesoporous silica, Ti-HMS, were tested as the solid phase substrates. Highly crystalline product was obtained within 30 min. after microwave irradiation with yields over 90% using $SiO_2-TiO_2$ xerogel, which showed essentially identical physicochemical properties to TS-1 prepared by conventional hydrothermal method. Excellent catalytic activity was also obtained for 1-hexene epoxidation using $H_2O_2.\;SiO_2-TiO_2$ particles prepared by thermal plasma and Ti-HMS were found inferior as a substrate for TS-1, probably due to difficulties in wetting the surface uniformly with TPAOH.

• Korean Journal of Materials Research
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• v.30 no.1
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• pp.22-30
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• 2020

Small fishing vessels are manufactured using FRP. Various studies have been conducted to increase the strength of the composite material by mixing alumina powder with resin. Tensile tests and flexural strength tests are conducted to examine the effect of alumina powder on the strength of GFRP. In the current study, resin/alumina composites at different alumina contents (i.e., 0, 1, 5, and 10 vol%) have been prepared. The physical and mechanical properties of the prepared composites have been investigated. From the results, the tensile strength of the specimen with alumina powder mixed in at 10% shows the highest value of 155.66 MPa. The tensile strength of the specimen mixed with alumina powder increases with the amount of alumina powder impregnated. In the flexural strength test, the flexural strength of neat resin without alumina powder has a highest value of 257.7 MPa. The flexural modulus of ALMix-5 has a highest value of 12.06 GPa. Barcol hardness of ALMix-10 has a highest value of 51. We show that alumina powder leads to decreasing cracks on the surface and decreasing length area of delamination.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1273-1279
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• 2007

The NiSO4 supported on Fe2O3 catalysts were prepared by the impregnation method. No diffraction line of nickel sulfate was observed up to 30 wt %, indicating good dispersion of nickel sulfate on the surface of Fe2O3. The addition of nickel sulfate to Fe2O3 shifted the phase transition of Fe2O3 (from amorphous to hematite) to higher temperatures because of the interaction between nickel sulfate and Fe2O3. 20-NiSO4/Fe2O3 containing 20 wt % of NiSO4 and calcined at 500 oC exhibited a maximum catalytic activity for ethylene dimerization. The initial product of ethylene dimerization was found to be 1-butene and the initially produced 1-butene was also isomerized to 2-butene during the reaction. The catalytic activities were correlated with the acidity of catalysts measured by the ammonia chemisorption method.