• Rapid Communication in Photoscience
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• v.3 no.2
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• pp.35-37
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• 2014

PEC (photoelectrochemical) water splitting for $O_2/H_2$ production is one of the promising but difficult way to utilize solar energy. Among photocatalytic materials for PEC water oxidation, $BiVO_4$ (Eg = 2.4 eV) has been recently intensively studied since it has various advantageous properties. But its maximum efficiency has not been realized owing to kinetic factors - slow water oxidation at surface & insufficient stability. These problems can be simultaneously solved by application of oxygen evolution catalyst (OEC) such as $CoO_x$, Co-Pi, $IrO_x$ etc. Herein we report the first successful application of $NiFeO_x$ OEC on $BiVO_4$, showing good performance compared to other effective OEC applied on $BiVO_4$ under basic conditions. The enhanced activity of OEC loaded $BiVO_4$ has been supported by the surface charge separation efficiency and electrochemical impedance studies.

• Journal of Industrial Technology
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• v.19
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• pp.75-79
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• 1999

Rotary bending fatigue tests were performed to investigate the effects of 2-phase matrix structure on fatigue limit with prepared specimens in high strength ductile irons. Two types of the specimens with different microstructures have been used. Series A has sorbite and series B has bainite. Fatigue limits of both specimens are improved comparing with as cast specimen. The fatigue limit is higher in series B than in series A. The reason why the fatigue limit of series A shows inferiority to that of series B is due to the transition of micro fatigue cracks to mesocrack occurs very rapidly, so increased stress intensity factor drives the fatigue crack growth. The higher fatigue limit of series B which has bainite is caused by the ${\gamma}$ layer contained in microstructure impede the rapid growth of micro fatigue crack to mesocrack and ${\alpha}$ layer around graphite has the higher capacity for the absorption of plastic deformation energy than sorbite.

• Journal of Advanced Marine Engineering and Technology
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• v.6 no.2
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• pp.21-41
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• 1982

Viscosity, especially characteristic among various properties of visco-elastic fluids such as high polymer solutions, is affected mainly by temperature and concentration. Hence, it is important for fluid engineering to express, by some equations, how the fluid characteristics vary with the change of temperature and concentration and to analyze them to obtain consistent viscous characteristics. High polymer solutions, synthetic products of modern chemical industry, suggest many interesting investigations because they are typical visco-elastic materials. Experimentation was made to derive some useful fluid characteristic equations of SEPARAN-NP10 (polyacylamide) expressed by n (flow behavior index) and K' (consistency index) when it is given temperature and concentration variation. To measure viscosity, capillary viscometer was adopted and the range of experimentation is 0-2,000 P.P.M. in concentration and 15-55 .deg.C in temperature. The experimental results are summarized as follows: The flow behavior index n 1) has nearly constant results irrespective of temperature variation at same conentration and the results are shown in (Table. 4-4-3) 2) has following equation, regardless of temperature, for the variation of concentration. n=-1.0765*10$^{-4}$ P+0.9915 (P:P.P.M.) The consistency index K' 1) has different results for the variation of temperature at same concentration and the results are given in (Table.4-7-2) 2) has following equation for the variation of concentration at same temperature. log 10$^{4}$K' =6.4785*10$^{-4}$ P-1.0529 (P:P.P.M)

• Journal of Korea Foundry Society
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• v.28 no.4
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• pp.184-189
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• 2008

Ag-Cd alloy has been widely used as an electrical contact material, since Ag-Cd alloy has a good wear resistance and stable contact resistance. But nowadays Ag-Cd alloy is not considered as electrical contact material any more due to detrimental effect on environments. Currently, active researches are being performed on ($Ag-SnO_2$ and $Ag-SnO_{2}-In_{2}O_{3}$) as an alternative solution which can fix the remaining environmental problems. However, $In_{2}O_{3}$ is relatively expensive and Ag-Sn alloy has low wear resistance. Our recent research results show that Ag-X%Zn-Y%Sn has similar physical and chemical properties. In the present study, so we tried to change and to optimize the Zn oxide content to over 6 wt% and Sn oxide content with 0.5, 1.0, 1.5 wt%. Results obtained from the experiments on the Ag-X%ZnO-Y%$SnO_2$ are discussed.

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.1934-1938
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• 2012

The reaction mechanism between cyclopropenylidene and formaldehyde has been systematically investigated employing the MP2/6-311+$G^*$ level of theory to better understand the cyclopropenylidene reactivity with carbonyl compound. Geometry optimization, vibrational analysis, and energy property for the involved stationary points on the potential energy surface have been calculated. Energies of all the species are further corrected by the CCSD(T)/6-311+$G^*$ single-point calculations. It was found that one important reaction intermediate (INTa) has been located firstly $via$ a transition state (TSa). After that, the common intermediate (INTb) for the two pathways (1) and (2) has been formed $via$ TSb. At last, two different products possessing three- and four-membered ring characters have been obtained through two possible reaction pathways. In the reaction pathway (1), a three-membered ring alkyne compound has been obtained. As for the reaction pathway (2), it is the formation of the four-membered ring conjugated diene compound. The energy barrier of the ratedetermining step of pathway (1) is lower than that of the pathway (2), and the ultima product of pathway (2) is more stable than that of the pathway (1).

• Preventive Nutrition and Food Science
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• v.10 no.2
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• pp.167-171
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• 2005

The anticancer and apoptotic effect of chloroform extract from 24 month-fermented doenjang were investigated in AGS human gastric adenocarcinoma cells. The chloroform extract of 24 month-fermented doenjang inhibited the AGS gastric cancer cell growth in a dose-dependent manner. It has been confirmed by observing the cell distribution under inverted microscope. Approximately, 48 hour treatment of $100\;{\mu}g/mL$ doenjang extract inhibited AGS cancer cell growth by $76.7\%$, respectively. The growth inhibition may be caused by apoptosis of AGS cancer cells after 48 hour treatment of 24 month-fermented doenjang extract. It has been demonstrated by cell cycle arrest that revealed the shift from $G_2+M\;to\;G_0+G_1$ phase and the formation of apoptotic bodies. The fermentation period playa critical role in cell cycle arrest, in which 24 month-fermented doenjang extract was more effective than 12 month-fermented doenjang extract. The treatment of 24 month-fermented doenjang extract for 48 hours has induced intercellular Bax and decreased Bcl-2 level, indicating that it may regulate the expression level of Bax/Bcl-2 proteins. Thus, 24 month-fermented doenjang extract seems to have anticancer effect via cancer cell growth inhibition induced by apoptosis process.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.1
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• pp.42-53
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• 2003

The purpose of this study is to evaluate the biotope structure of the city center area of Jung-gu for nature experiences and recreation purposes. Jung-gu is the most extremely and rapidly urbanized area of Daegu. This study was conducted under the assumption that the biotope structure of a city center area would be different from the urban area. The results of this study are as follows: 1) There are 11 biotope type groups as designated as commercial and work-area biotope type group, and 41 detailed biotope types designated as commercial areas with a lack of greenspace biotope type. 2) The commercial and work area biotope type group has the largest area with 34% of the total area, and the square biotope type group has the smallest area with 34% of total area. 3) The result of primary biotope evaluation is that there are 12 biotope types that have greater than third grade, apart from the biotope type of park that includes natural vegetation. The first grade of biotope type has not appeared in this area, however, the fifth grade of biotope type has 20 biotope types with the biotope type of construction work area (JA). 4) The results of the secondary biotope evaluation are 1 biotope for la, 9 biotopes for 2a, 9 biotopes for 2b, 14 biotopes for 2c and no biotope for 2a. This study suggests that a detailed investigation and improvement plan for high-value biotope areas in the city center area must be continued.

• Korean Journal of Metals and Materials
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• v.46 no.7
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• pp.443-448
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• 2008

Contact materials are used in many electrical devices. Ag-Cd alloy has been widely used in electrical part, because Ag-Cd alloy has a good wear resistance and stable contact resistance. But nowadays Ag-Cd alloy isn't being used because of environmental challenges. Currently new research is being done on ($Ag-SnO_2$ and $Ag-SnO_2-In_2O_3$) as an alternative solution to fix any remainly environmental challenges. However $In_2O_3$ is more expensive and Ag-Sn alloy has low wear resistance. According to our research data Zn has a similar physical and chemical property. In this work, so we changed and optimized the Zn oxide to over 4 and added Sn oxide ratio 0.5, 1.0, 1.5wt%. Conclusions from the data recorded from the experiment of $Ag-ZnO-SnO_2$ are as follows.

• The Korean Journal of Food & Health Convergence
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• v.5 no.3
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• pp.21-33
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• 2019

The incidence of both obesity and Type 2 Diabetes Mellitus( DM) is increasing proportionately so that causes of deaths from these has overtaken from that of malnourishment. Hence it has been recommended to treat the 2 in parallel considering the role of diabesity on health. Important causes of T2DM are insulin resistance (IR) and /or inadequate insulin secretion. Protein tyrosine phosphatase 1B(PTPIB) has a negative impact in insulin signaling pathways and hence plays crucial role inT2DM,since its overexpression might induce IR. Thus PTPIB is considered a therapeutic target for both obesity and T2DM, there has been a search for novel ,promising natural inhibitors. We conducted a pubmed search for articles related to PTPIB inhibitors from natural causes be it marine sources or other natural sources. Out of 988 articles we selected 100 articles for review. Thus various bioactive molecules isolated from marine organisms that can acts as PTPIB Inhibitors and thus possess antidiabetic activity both in vitro/ in vivo studies ,besides products from fruits like Chinese raspberry or curcumin used as routine spices are described with their chemical classes, structure-activity relationships and potency as assessed by IC 50 values are discussed. More work is required to make this a reality.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.6
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• pp.381-387
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• 2020

According to the increase of concern for environmental problems, the energy saving becomes an important issue because it is one of the most effective methods of decreasing CO2 which is major environmental problem. In the present study, the post device after propeller related with rudder has been focussed. Recently the full-spade twisted rudder has been frequently used not only to increase the efficiency but also to remove the cavitation risk on leading edge. In addition to that the rudder bulb is also applied to the rudder to increase the propulsion efficiency as well as to minimize the cavitation erosion risk around twisting part. The parametric study has been conducted for investigating the optimum configuration of twisting rudder with bulb by CFD. The present optimization has been applied to the KVLCC2 full-body ship. The verification of the computed results is also expected to be conducted by the comparison with experimental results in the near future.