Effect of potassium addition on bimetallic PtSn supported θ-Al₂O₃ catalyst for n-butane dehydrogenation to olefins

Nagaraja, B.M.,Jung, H.,Yang, D.R.,Jung, K.D. Elsevier Science Publishers 2014 CATALYSIS TODAY - Vol.232 No.-

PtSn/θ-Al<SUB>2</SUB>O<SUB>3</SUB> catalysts with different amount of potassium (0.4, 0.7, 0.95, 1.2 and 1.45wt.%) were prepared by an impregnation method, and their catalytic activity in n-butane dehydrogenation was investigated at 823K, an atmospheric pressure and a GHSV of 18,000mL(g<SUB>cat</SUB>h)<SUP>-1</SUP>. The compositions listed in order of n-C<SUB>4</SUB><SUP>=</SUP> yields at 823K were as follows: K<SUB>0.95</SUB>(PtSn)<SUB>1.5</SUB>>(PtSn)<SUB>1.5</SUB>>K<SUB>0.4</SUB>(PtSn)<SUB>1.5</SUB>>K<SUB>0.7</SUB>(PtSn)<SUB>1.5</SUB>>K<SUB>1.2</SUB>(PtSn)<SUB>1.5</SUB>>K<SUB>1.45</SUB>(PtSn)<SUB>1.5</SUB>>K<SUB>0.9</SUB>(Pt)<SUB>1.5</SUB>. The K<SUB>0.9</SUB>(Pt)<SUB>1.5</SUB> and K<SUB>0.95</SUB>(Sn)<SUB>1.5</SUB> catalyst severely deactivated in n-butane dehydrogenation. The (PtSn)<SUB>1.5</SUB> (without K) catalyst showed the highest n-butane conversion, while K<SUB>0.95</SUB>(PtSn)<SUB>1.5</SUB> did the highest n-C<SUB>4</SUB><SUP>=</SUP> yield. The small amount of potassium on bimetallic PtSn/θ-Al<SUB>2</SUB>O<SUB>3</SUB> catalyst improved n-C<SUB>4</SUB><SUP>=</SUP> selectivity, but slightly decreased n-butane conversion, resulting in the increase of n-C<SUB>4</SUB><SUP>=</SUP> yield. The effect of potassium was caused by blocking the acid sites of Pt catalyst. The TPR and HAADF STEM-EDS study suggested the reduction procedure of the Pt, Sn and K species. However, the higher loaded potassium (1.2 and 1.45wt.%) doped (PtSn)<SUB>1.5</SUB> catalysts were rather highly deactivated because the sizes of Pt particles were increased by weakening the interaction between Pt and Sn. The n-C<SUB>4</SUB><SUP>=</SUP> selectivity of the (PtSn)<SUB>1.5</SUB> catalyst increased with respect to the reaction, while that of the potassium doped catalysts maintained the high n-C<SUB>4</SUB><SUP>=</SUP> selectivity from the beginning of the reaction. Also, different alkali metals (Ca, Na and Li) were tested for the comparison with K. The potassium doped catalyst showed the highest n-C<SUB>4</SUB><SUP>=</SUP> yield among the other alkali metals for n-butane dehydrogenation.

Cooperative Activation of PI3K by Ras and Rho Family Small GTPases

Yang, H.,Shin, M.G.,Lee, S.,Kim, J.R.,Park, W.,Cho, K.H.,Meyer, T.,Do Heo, W. Cell Press 2012 Molecular cell Vol.47 No.2

Phosphoinositide 3-kinases (PI3Ks) and Ras and Rho family small GTPases are key regulators of cell polarization, motility, and chemotaxis. They influence each other's activities by direct and indirect feedback processes that are only partially understood. Here, we show that 21 small GTPase homologs activate PI3K. Using a microscopy-based binding assay, we show that K-Ras, H-Ras, and five homologous Ras family small GTPases function upstream of PI3K by directly binding the PI3K catalytic subunit, p110. In contrast, several Rho family small GTPases activated PI3K by an indirect cooperative positive feedback that required a combination of Rac, CDC42, and RhoG small GTPase activities. Thus, a distributed network of Ras and Rho family small GTPases induces and reinforces PI3K activity, explaining past challenges to elucidate the specific relevance of different small GTPases in regulating PI3K and controlling cell polarization and chemotaxis.

Improved production of phleichrome from the phytopathogenic fungus Cladosporium phlei using synthetic inducers and photodynamic ROS production by phleichrome

So, K.K.,Jo, I.S.,Chae, M.S.,Kim, J.M.,Chung, H.J.,Yang, M.S.,Kim, B.T.,Kim, J.K.,Choi, J.K.,Kim, D.H. Society for Bioscience and Bioengineering, Japan ; 2015 Journal of bioscience and bioengineering Vol.119 No.3

Two different diketopiperazines, cyclo-(l-Pro-l-Leu) and cyclo-(l-Pro-l-Phe), which were isolated from the culture filtrate of Epichloe typhina and found to be inducers of phleichrome production, were chemically synthesized and evaluated for use in the improved production of phleichrome from wild-type and UV-mutagenized strains (M0035) of Cladosporium phlei. When supplemented with PDA and V8 juice agar media, both inducers showed significant increases in the production of phleichrome. Phleichrome production was increased in a dose-dependent manner up to a concentration of maximum yield for both inducers. No further significant induction was observed by supplementing inducers over the concentration of maximum yield. Among the two inducers, cyclo-(l-Pro-l-Phe) showed better inducing capability than cyclo-(l-Pro-l-Leu). The maximum yield was observed from the M0035 strain grown on V8 juice media supplemented with 150 μM cyclo-(l-Pro-l-Phe), which was estimated to be 232.6 mg of phleichrome per gram of mycelia and 10.2 mg of secreted phleichrome per 20 agar-plugs. Interestingly, growth inhibition was observed on V8 juice agar media with 100, 150, and 200 μM cyclo-(l-Pro-l-Phe) but not on PDA with the same amount of inducer, which suggests that the inhibitory effect might be through the overproduction of phleichrome rather than the toxic effect of the inducer itself. Superoxide production by purified phleichrome was dramatically stimulated upon illumination, thus demonstrating photodynamic production of superoxide in vitro by phleichrome.

3차원 CFD 시뮬레이션을 이용한 돔형 저온저장고 개발

양길모,고학균,홍지향 한국농업기계학회 2003 바이오시스템공학 Vol.28 No.1

This study was conducted to develop proper model for cold storage facility that could offer uniform heat movement and air movement for green grocery and improve improper of the existing container-type cold storge facility.For that reason, new model(dome-type) cold storage facility was developed using 3-DCFD(computational fluid dynamics) simulation. The size was 6m×6m×5m. Its size and configuration were same to simulation model. Unit cooler was designed to send cold air in 4 side ways. A dome-type cold storage facility showed uniform distributions of air temperature and velocity because cold air was forced to move down along the ceiling and the wall and then circulated to the unit cooler from the central part of the floor. Dome-type cold storage facility also showed by low wind velocity, below 1 m/s that could minimized cold damage and quality deterioration.

Effects of scoparone on dopamine release in PC12 cells

Yang, Y.J.,Lee, H.J.,Lee, B.K.,Lim, S.C.,Lee, C.K.,Lee, M.K. Inverni Della Beffa S.p.A ; Elsevier Science 2010 Fitoterapia Vol.81 No.6

The effects of scoparone on dopamine release in PC12 cells were investigated. Scoparone at 50-200@?M increased dopamine release into the culture medium. However, the released levels of dopamine by scoparone were not altered in the absence of extracellular Ca<SUP>2+</SUP> and by adenylyl cyclase inhibitor MDL-12,330A. Scoparone increased phosphorylation of PKA, CaMK II and synapsin I. Scoparone also enhanced K<SUP>+</SUP>-induced levels of dopamine release by CaMK II phosphorylation. These results suggest that scoparone increases dopamine release by synapsin I phosphorylation via activation of PKA and CaMK II, which are mediated by cyclic AMP levels and Ca<SUP>2+</SUP> influx.

Photoluminescence Investigation of Thick GaN Films Grown on Si Substrates by Hydride Vapor Phase Epitaxy

M.Yang,H.S.Ahn,J.H.Chang,S.N.Yi,K.H.Kim,H.Kim,김석환 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.43 No.6

The optical properties of thick GaN lms grown by hydried vapor phase epitaxy (HVPE) using a low-temperature intermediate GaN buer layer grown on a (111) Si substrate with a ZnO thin lm were investigated by using photoluminescence (PL) measurement at 300 K and 77 K. The strong donor bound exciton (DBE) at 357 nm with a full width at half maximum (FWHM) of 15 meV was observed at 77 K. The value of 15 meV is extremely narrow for GaN grown on Si substrate by HVPE. An impurity-related peak was also observed at 367 nm. The origin of impurity was investigated using Auger spectroscopy.

제주도 중산간지대 공동목장의 토양, 목초, 육우혈청중 계절별 유기질소 및 무기물 함량

양기천,정창조,김규일,김문철 제주대학교 농과대학 제주도축산문제연구소 1989 畜産論叢 Vol.4 No.1

Organic nitrogen and mineral contents in so, forages and blood serum of beef cattle sampled in June-July and September-October in 1987 from 12 different pasture areas of Cheju island were determined and the results are summarized as follows: 1. The contents of all mineral studied were significantly different (p<0.01) between soils of different pastures sampled in June-July. and the contents of P, Mg, Fe, Na. Ca and Zn were significantly different (P<0.01) between soils of different pastures sampled in September-October. The contents of P and Ca were much higher in soils sampled in June-July than in soils sampled in September-October. but the contents of K and Mg were opposite to those of P and Ca. 2. N, P, Mg. Cu and Co contents of orchard grass sampled in June-July were significantly different (P<0.01 ) between the pastures, and K, Ca, Mg, Na and Co contents of orchard grass sampled in September-October were significantly different (P<0.01) between the pastures. Cu, Fe, Na, Cu and Zn contents were higher in orchard grass sampled in September-October than in that sampled in June- July. 3. Except for Mg, mineral contents of ladino clover sampled in June-July were different between the pastures, and N, Ca, Mg, Fe, Na and Zn contents were significantly higher in ladino clover than in orchard grass. 4. The contens of Zn and Fe in blood serum of beef cattle sampled in June-July were significantly different (P<0.01) between the pastures and the contents of K, Ca, Mg, Na and Co in that sampled in September-October were different between the pastures. No difference was found in serum mineral contents between beef cattle from different pastures. 5. Serum Co content (0.07ppm) in the cattle raised in lsidore was below the normal, Co deficiency being suspected. Serum contents of the other minerals were found to be normal in the cattle of all pastures. 6. Only Fe content was significantly (p<0.05) correlated between the content of forages and the blood serum(R=0.84).

Prussian blue-functionalized magnetic nanoclusters for the removal of radioactive cesium from water

Yang, H.M.,Jang, S.C.,Hong, S.B.,Lee, K.W.,Roh, C.,Huh, Y.S.,Seo, B.K. Elsevier Sequoia 2016 JOURNAL OF ALLOYS AND COMPOUNDS Vol.657 No.-

Prussian blue-functionalized magnetic nanoclusters were fabricated for the highly efficient removal of radioactive cesium (such as <SUP>137</SUP>Cs) and rapid magnetic separation of absorbent from <SUP>137</SUP>Cs-contaminated water. The magnetic nanoclusters, synthesized via the hydrothermal method, were coated with Prussian blue (PB) via a simple reaction with potassium hexacyanoferrate under acidic conditions. The resulting Prussian blue-functionalized magnetic nanoclusters had a large distribution coefficient, even in the presence of 3000 ppm competing ions such as K<SUP>+</SUP>, Na<SUP>+</SUP>, Ca<SUP>2+</SUP> and Mg<SUP>2+</SUP>, and excellent removal efficiency (>99.7%) of radioactive cesium from contaminated water. Furthermore, they possess good saturation magnetization values (27.5 emu/g), allowing for rapid separation from an aqueous solution using an external magnetic field. Therefore, these magnetic adsorbents have promising applications for the treatment of radioactive cesium-contaminated water.

보건요원 교육효과 평가

황금복,전미순,김태숙,양병국,정은경,양숙자,김귀향 국립보건연구원 1998 국립보건원보 Vol.35 No.-

Experimental study of flow boiling heat transfer and dryout characteristics at low mass flux in helically-coiled tubes

Hwang, K.W.,Kim, D.E.,Yang, K.H.,Kim, J.M.,Kim, M.H.,Park, H.S. North-Holland Pub. Co 2014 Nuclear engineering and design Vol.273 No.-

The goals of this study were to understand flow boiling phenomena in helically-coiled tubes and to predict their flow boiling heat transfer coefficients (HTC) and dryout qualities. Flow heat transfer and dryout were experimentally investigated in coiled tubes of 12-mm inside diameter and 17-mm outside diameter. The helical diameters D<SUB>h</SUB> of the coiled tubes used were 606mm and 977mm for the HTC experiments and 606mm, 977mm, and 1290mm for the dryout experiments. In flow boiling experiments mass flux G was 88.4-530.5kg/(m<SUP>2</SUP>s), system pressure P was 1-6MPa, and heat flux q'' to the tube wall was 30.0-1145.3kW/m<SUP>2</SUP>. For dryout experiments, q'' was 131.3-1764.9kW/m<SUP>2</SUP>. Flow boiling heat transfer in the coiled tubes was significantly affected by nucleate boiling and convective boiling, and not by secondary flow due to the helical coiling. HTC in the coiled tubes were accurately predicted (standard deviation 29%) by Steiner and Taborek HTC correlation for straight vertical tubes. Dryout qualities were significantly influenced by the coiled tubes. The effects of D<SUB>h</SUB>, G, and P were greatly affected by secondary flow caused by the coiled tubes. Dryout in the coiled tubes can be only predicted using dryout correlations for them. The dryout map proposed by Berthoud and Jayanti was modified to consider the effects of redeposition and gravity; this modified correlation accurately predicted dryout qualities (standard deviation 10.1%) within the range of experimental conditions. These results will help guide design of cooling systems that use helical coils.