• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1332-1340
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• 2009

The front end wheel loader is widely used for the loading of materials in mining and construction fields. It has repetitive digging, loading and dumping procedures. The bucket is subjected to large resistance force from the soil during scooping. We considered the soil reaction force characteristics from scooping procedure, the protection by overload and automatic scooping mode algorithm. The main topic of this paper is the analysis of the soil reaction force characteristics. The analysis of soil mechanics is carried out and the developed soil model is verified by experimental results from the simplified experimental equipment. A simplified model of the soil shape and bucket trajectory is used to determine the scooping direction based on an estimation of the resistance force applied on the bucket during the scooping motion. In the future, this model will be used for the generation of an appropriate path for the wheel loader automation.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.267-274
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• 2009

Considerable attention has been given to developing methodologies to reduce the emission of carbon dioxide from industry to meet strengthened environmental regulations. In this article, recent research trends on dry reforming of methane as an alternative method to reduce $CO_2$ emission from large scale industrial processes are addressed. To efficiently provide the energy needed in this strong endothermic reaction without additional $CO_2$ emission, it seems to be desirable to adopt autothermal reaction mode. The produced synthesis gas could be used as a reducing gas, or a feedstock for synthesis of chemicals and fuels.

• Korean Journal of Microbiology
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• v.27 no.1
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• pp.35-42
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• 1989

The mode of transglycosylation reaction observed during the action of low-molecular-weigh $\beta$-D-glucosidase ($\beta$-D-glucoside glucohydrolase, EC3.2.1.21) purified from Trichoderma koningii ATCC 26113 was investigated using $^{1}H$-NMR spectroscopy. The enzyme was purified by the series of procedures including ammonium sulfate precipitation, and fractionations by column chromatographies on Bio-Gel P-150, DEAE-Sephadex A-50, and SP-Sephadex C-50. The final purification was performed by the band eluation after preparative polyacrylamide gel electrophoresis. The enzyme showed its molecular size of 78,000 through the analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and its isoelectric point of 5.80 through the analysis of analytical isoelectric focusing. The H-1 proton resonances were analyzed. After the reaction of the enzyme with cellobiose, the reaction products were separated by high performance liquid chromatography using refractive index detector. H-1 resonances of the products were consisted with those of gentiobiose [$\beta$-D-glucopyranosyl--(1,6)-D-glucopyranose], and cellotriose [$\beta$-D glucopyranosyl-(1,4)-$\beta$-D-glucopyranosyl]-(1,4)-D-glucopyranose] with minor resonances of sophorose [$\beta$-D-glucopyranosyl-(1,2)-D-glucopyranose], respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.3
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• pp.320-326
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• 1999

Aluminum oxynitride spinel (ALON) was synthesized by the direct melt nitridation (DMN) process using aluminum metal and aluminium oxide. The amount of ALON increased with increasing the reaction sintering temperature. The specimen containing up to 10 wt% Al showed ALON phase only when heat-treated beyond $1750^{\circ}C$. Whereas the specimen composed of more than 12 wt% Al showed unreacted AlN phase. Bulk density of reaction-sintered specimen was increased with increasing sintering temperature, except the speimen containing unreacted AlN where the density slightly decreased when heat-treated beyond $1750^{\circ}C$, Transgranular fracture mode was observed predominantly in the specimen with higher Al content.

• Journal of Electrochemical Science and Technology
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• v.2 no.1
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• pp.14-19
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• 2011

Quasi-equilibrium profiles are analyzed through galvanostatic intermittent titration technique (GITT) and potentiostatic intermittent titration technique (PITT) to study the charge/discharge mechanism in multicomponent olivine structure ($LiMn_{1/3}Fe_{1/3}Co_{1/3}PO_4$). From GITT data, the degree of polarization is evaluated for the three regions corresponding to the redox couples of $Mn^{2+}/Mn^{3+}$, $Fe^{2+}/Fe^{3+}$ and $Co^{2+}/Co^{3+}$. From PITT data, the current vs. time responses are examined in each titration step to find out the mode of lithium de-intercalation/intercalation process. Furthermore, lithium diffusivities at specific compositions (x in $Li_xMn_{1/3}Fe_{1/3}Co_{1/3}PO_4$) are also calculated. Finally, total capacity ($Q^{total}$) and diffusional capacity ($Q^{diff}$) are obtained for some selected voltage steps. The entire study consistently confirms that the charge/discharge mechanism of multicomponent olivine cathode is associated with a one-phase reaction rather than a biphasic reaction.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.4
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• pp.609-619
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• 1996

Experimental study on effects of factors on the reaction crystallization of silver chloride in rushton type reactor. The size and size distributions of the silver chloride crystals were observed to be markedly affected by the agitation speed of solution, and feeding rate, feeding mode and concentration of reactants. From experimental data it was inferred that in the reaction crystallization of silver chloride the supersaturation level of silver chloride and concentration of excess ions in the solution, and mass transfer rate around the crystals were implicitly interrelated with factors and directly affected on the crystal nucleation and grwoth processes. However, the morphology of the silver chloride crystal was not changed by factors.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.5
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• pp.494-502
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• 2016

A 1-dimensional heterogeneous reactor model with the gas-solid interfacial phase gradients was developed for the simulation of the packed bed reactor where the exothermic reversible water gas shift reaction for the natural gas steam reformed gas was proceeding in adiabatic mode. Experimental results obtained over the WGS catalyst, C18-HA, were best simulated when the frequency factor of the reaction rate constant was adjusted to a half the value reported over another WGS catalyst, EX-2248, having the same kinds of active components as the C18-HA. For the reactor of the inside diameter 158.4 mm and the bed length 650 mm, the optimum feeding temperature of the reformed gas was simulated to be $194^{\circ}C$, giving the lowest CO content in the product gas by 1.68 mol% on the basis of dried gas. For reactors more extended in the bed length, the possible lowest CO content in the product gas with the optimum feeding temperature of the reformed gas were suggested.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.339-339
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• 2010

The metallic nanoparticles (Pt, Au, Ag. Cu, etc.) supported on ceria-titania mixed oxide exhibit a high catalytic activity for the water gas shift reaction ($H_2O\;+\;CO\;{\leftrightarrow}\;H_2\;+\;CO_2$) and the CO oxidation ($O_2\;+\;2CO\;{\leftrightarrow}\;2CO_2$). It has been speculated that the high catalytic activity is related to the easy exchange of the oxidation states of ceria ($Ce^{3+}$ and $Ce^{4+}$) on titania, but very little is known about the ceria titanium interaction, the growth mode of metal on ceria titania complex, and the reaction mechanism. In this work, the growth of $CeO_x$ and Au/$CeO_x$ on rutile $TiO_2$(110) have been investigated by Scanning Tunneling Microscopy (STM), Photoelectron Spectroscopy (PES), and DFT calculation. In the $CeO_x/TiO_2$(110) systems, the titania substrate imposes on the ceria nanoparticles non-typical coordination modes, favoring a $Ce^{3+}$ oxidation state and enhancing their chemical activity. The deposition of metal on a $CeO_x/TiO_2$(110) substrate generates much smaller nanoparticles with an extremely high activity. We proposed a mechanism that there is a strong coupling of the chemical properties of the admetal and the mixed-metal oxide: The adsorption and dissociation of water probably take place on the oxide, CO adsorbs on the admetal nanoparticles, and all subsequent reaction steps occur at the oxide-admetal interface.

• YAKHAK HOEJI
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• v.44 no.5
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• pp.379-383
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• 2000

Stanozolol (STZ, 17$\alpha$-methyl-17$\beta$-hydroxy-5$\alpha$-androstano-(3,2-c) pyrazole), an anabolic steroid, is an abused drug by body-builders or atheletes, as well as medicine for treatment of aplastic anemia and vascular thrombosis. In human volunteers, the major urinary metabolite of STZ was reported to be 3'-hydroxystanozolol that was identified by gas chromatography-mass selective detector (GC/MSD). The objective of this experiment is to investigate the in vitro metabolism of STZ in liver S-9 faction of polychlorinated biphenyl-induced rats. Reaction mixture including STZ as substrate and the S-9 faction was extracted with diethyl ether and quantified by the selected ion monitoring mode of GC/MSD. The selected concentration of substrate STZ is 100 nmole and the selected time for incubation in the reaction mixture was determined to 60 min. The amount of 3'-hydroxystanozolol produced was increased by about 6-fold in the reaction medium including the liver S-9 fraction of polychlorinated biphenyl-induced rats, compared to that of untreated rats. Inhibitors of cytochrome P450, SKF-525A and 7,8-benzoflavone, decreased the production of 3'-hydroxystanozolol by about 89~100% and 65~75%, respectively; In conclusion, hydroxylation of STZ into 3'-hydroxystanozolol is confirmed by GC/MSD and is catalyzed by cytochrome P450.

• Journal of the Korean Society of Tobacco Science
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• v.9 no.2
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• pp.69-75
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• 1987

Nicotine, the main alkaloid of tobacco, showed different effect according to the enzyme. Among investigated enzymes, protease was inactivated remarkably by nicotine and the mode of inhibition was examined. $\alpha$-amylase and $\beta$-amylase were not affected, and cellulase and glucoamylase were inactivated partially when the concentration of it was over 1.0% , but protease was inhibited powerfully by nicotine The inhibition of protease by nicotine was performed almost in the initial stage of reaction, and was not so much affected by temperature, and was reversible. The inhibition type of protease by nicotine appeared as a Mixed-type inhibition.