• Journal of Magnetics
• /
• v.16 no.2
• /
• pp.161-163
• /
• 2011

We report results of first principles calculations for effects of an external electric field (E-field) on the magnetocrystalline anisotropy (MCA) in transition-metal (Fe, Co, and Ni) monolayers and at metal-insulator (Fe/MgO) interfaces by means of full-potential linearized augmented plane wave method. For the monolayers, the MCA in the Fe monolayer (but not in the Co and Ni) is modified by the E-field, and a giant modification is achieved in the $Fe_{0.75}Co_{0.25}$. For the Fe/MgO interfaces, the ideal Fe/MgO interface gives rise to a large out-of plane MCA, and a MCA modification is induced when an E-field is introduced. However, the existence of an interfacial FeO layer between the Fe layer and the MgO substrate may play a key role in demonstrating an Efield-driven MCA switching, i.e., from out-of-plane MCA to in-plane MCA.

• Journal of Surface Science and Engineering
• /
• v.49 no.6
• /
• pp.567-574
• /
• 2016

We have analyzed chemical properties of polysiloxane and polysilazane films, respectively, as sealing materials for electrostatic chuck (ESC) and have investigated the possibility of polysilazane as an alternative sealant to polysiloxane. It has been revealed that Si-O with organic bonding ($Si-CH_3$) existed in polysiloxane films compared to only pure Si-O bonding in polysilazane films. The sealing property of polysilazane has been found outstanding even in a short time of application. In the polysiloxane films containing $H_2O$, pin holes have been found possibly due to $CO_2$ gas evolution, and low adhesion with Si substrate has been observed after heat stress test in connection with the existence of organic bonding. After acid resistance test in 0.5 vol.% HF, 68 wt.% $HNO_3$, and 37 wt.% HCl solution, polyilazane films have shown a longer survival times. Compared to the conventional polysiloxane sealant, polysilazane is expected as a new sealing material because of good thermal and chemical stability.

• Journal of the Korean Applied Science and Technology
• /
• v.13 no.1
• /
• pp.67-74
• /
• 1996

This study was conducted to find a catalyst system which has high conversion and selectivity for the oxidative coupling of methane to produce ethane and ethylene. Various catalysts were tested in a fixed bed reactor ar $750^{\circ}C$, 1 atm, and the feed ratio($CH_4/O_2$) of 2/1. Under the reaction condition, 10wt%$PbSO_4/MgO$ catalyst showed the highest catalytic activity : methane conversion, $C_2$ selectivity and yield were 50, 40 and 20%, respectively. Catalysts containing sulfate compounds, 10wt%$PbSO_4/MgO$, 10wt%$MgSO_4/MgO$ and $Na_2SO_4/MgO$ revealed a moderate methane conversions such as 38, 50 and 50%, respectively and low $C_2$ selectivities such as 18, 5 and 9%, respectively. Catalysts containing carbonate compounds, 10wt%$PbCO_3/MgO$, 10wt%$Li_2CO_3/MgO$ and $NaCO_3/MgO$, also showed a moderate methane conversions such as 64, 44 and 51%, respectively and low $C_2$ selectivities such as 5, 6 and 2%, respectively. With the existence of chlorine and mercury, $C_2$ selectivity was decreased.

• Agribusiness and Information Management
• /
• v.12 no.2
• /
• pp.40-54
• /
• 2021

Market integration and prices in pulse crops like black gram play an important role in determining the production decisions of the farmers and diversification towards high value nutritious crops. In this context, the present study explores extent of market integration and price transmission in selected major black gram markets in Andhra Pradesh using Johansen co-integration, Vector Error Correction Model and Granger causality test. The study used monthly prices data of black gram (Rs/quintal) sourced from selected markets of Srikakulam, Krishna and Kurnool spanning January, 1990 to December, 2019. The results of the study strongly buttressed the existence of co-integration and interdependence of selected black gram markets in Andhra Pradesh. However, the speed of adjustment of the prices found to be moderate in Krishna market and quite weaker in Srikakulam market and thereby prices correct a small percentage of the disequilibrium in these markets with the greatest percentage by the external and internal forces. So, it necessitates the need for future research, to investigate the influence of external and internal factors such as market infrastructure, Government policy and self-sufficient production, product characteristics and utilization towards market integration. As there exists only unidirectional causality from Krishna to Kurnool and from Krishna to Srikakulam markets, it calls for strengthening the information technology for flow of market information regularly to help the farmers for increasing their income.

• Journal of Yeungnam Medical Science
• /
• v.38 no.1
• /
• pp.70-73
• /
• 2021

Relapsing polychondritis (RP) is a rare, progressive immune-mediated systemic inflammatory disease of unknown etiology, characterized by recurrent inflammation of cartilaginous structures. Approximately 30% of RP cases are associated with other autoimmune diseases. However, the co-occurrence of RP and Crohn disease (CD) has rarely been reported. Herein, we present a 35-year-old woman diagnosed with RP and CD, who was refractory to initial conventional medications, including azathioprine and glucocorticoid, but who subsequently responded to infliximab (IFX). For both diseases, remission was sustained with IFX. There has been no previous report regarding the successful treatment of co-existing RP and CD with IFX.

• Geomechanics and Engineering
• /
• v.34 no.1
• /
• pp.87-102
• /
• 2023

The cover plate and the building loads often make the semi-covered deep excavations with existing buildings bearing asymmetric load, presenting different deformation characteristics with normal excavations, which is not absolutely clear in current studies. Based on a typical engineering, the building storeys, the basement storeys, the pile length, the existence of the cover plate (CP) and the depth of the diaphragm walls (DW) were selected as variables, and 44 groups of simulation were designed to study the influence of existing buildings and the semi-covered supporting system on the deformation of the excavations. The results showed that the maximum lateral displacement of DW, δ_hm, and the depth of δ_hm, H_m, are affected seriously by the building storeys and the basement storeys. Asymmetric structures and loading lead to certain lateral displacement of DW at the beginning of excavation, resulting in different relationships between δ_hm and excavation depth, H. The maximum surface settlement outside the pit, δ_vm, increases significantly and the location, d_m, moves away from the pit with the building storeys increases. δ_vm has a quadratic correlation with H due to the existing buildings. CP and building load will affect the style of the lateral displacement curve of DW seriously in different aspects.

• Laser Solutions
• /
• v.16 no.3
• /
• pp.1-10
• /
• 2013

In this study, Al-Si coated boron steel(1.2 mm) were laser welded by $CO_2$ laser and hot-stamping was applied to the laser joints. Tensile properties and microstructures of the joints were investigated before and after hot-stamping. Tensile and yield strengths of the as welded specimen similar with base metal and fracture occurred base metal of boron steel. Although, in case of heat treated specimen, fracture occurred fusion zone that Al segregated zone near the bond line. These could be explained by the existence of ferrite, in the Al segregated zone near the bond line and base metal of boron steel. Before hot-stamping, hardness of base metal is lower than fusion zone and heat affected zone in spite of exist Al segregation zone($Fe_3$(Al,Si)). So fracture occurred base metal. Although, after hot-stamping, microstructure of base metal and welds zone transformed to martensite and bainite except in Al segregation zone near the bond line that $Fe_3$(Al,Si) transformed to a-ferrite. So fracture occurred Al segregation zone near the bond line.

• Health Policy and Management
• /
• v.18 no.2
• /
• pp.86-106
• /
• 2008

This research analyzed. knowledge structure and its effect factor by analysis of co-author and keyword network in Korea's health policy and administration sector. The data was extracted from 339 articles listed in the Korean Journal of Health Policy and Administration, and was transformed into a co-author and keyword matrix. In this matrix the existence of a link was defined by impact factors which were calculated by the weight value of what the role was and the rate of how many authors contributed. We demonstrated that the research achievement was dependent on the author's status and network index. Analysis methods were neighborhood degree, correspondence analysis, multiple regression and the difference of weight distribution by research fields. Co-author networks were developed as closeness centrality as well as degree centrality by a few high productivity researchers. In particular, power law distribution was discovered in impact factor and research productivity. The effect of the author's role was significant in both the impact factor calculated by the participatory rate and the number of listed articles. Especially, this journal shared its major researchers who had a licensed physician with the Journal of Preventive Medicine and Public Health. Therefore, social scientists were likely to be small co-author network differently from natural scientists. It was so called 'two cultures' phenomenon. This study showed how can we verified academic research structure existed in the unit of journal like as citation networks. The co-author networks in the field of health policy and administration had more differentiated and clustered than preventive medicine and epidemiology fields.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.39 no.2
• /
• pp.83-88
• /
• 2013

The aqueous two phase system has biocompatibility, because it is physically separated into an immiscible liquid multi-layer induced by incompatibility among hydrophilic components dissolved in the water phase. we have applied this principle to aqueous multi-layer liquid cosmetics and select two representative systems. What it was experimentally obtained was the phase diagrams including a binodal curve, a critical point, tie lines of concentration and tie curves of phase separating volume ratio and phase separating time. From the phase diagrams, we were able to observe existence of the optimum condition to prepare the aqueous multi-layer cosmetics for the systems.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.169-169
• /
• 1999

We studied magnetic properties of co thin films deposited on Pd (111) surface, which attracted much attention recently due to the perpendicular magnetic anisotropy, using magnetic circular dichroism(MCD). Special attention was paid on the effect of Pd capping and interface roughness on the direction of magnetic easy axis, and for that purpose MCD signals for all Co thicknesses were measured with two different ways : in-plane and out-of-plane geometry. In case of bare Co films deposited on smooth Pd(111) surface, no MCD signal was observed under 4$\AA$ co thickness. At 4$\AA$ Co thickness, MCD signal at the out-of-plane geometry was observed, and for thicker Co films, only in-plane MCD signal was measured. This type of magnetic easy axis transition has been reported for other cases like Co/Pt system. The effect of 5$\AA$ Pd capping on these bare Co films made an remarkable change on the transition of magnetic easy axis. Out-of-plane MCD signals exists up to 20$\AA$ Co thickness, and disappears at 24$\AA$ Co thickness. In-plane MCD signals first appears at 10$\AA$ Co thickness and gradually increases up to 24$\AA$ Co thickness. Between 10$\AA$ and 20$\AA$ Co thickness, in-plane and out-of-plane MCD signal coexist. The formation of multi-domain structure or the existence of tilted magnetic easy axis is an possible scenario for such an interesting coexistence. The effect of interface roughness was also tested by measuring MCD signal on Co films deposited on un-annealed Pd(111) surface. Out-of-plane MCD signal was observed up to 8$\AA$ Co thickness and the anisotropy of MCD signal at 4$\AA$ Co thickness was very large with respect to that of Co film deposited on the smooth substrate. Above 8$\AA$ thickness, there exists only in-plane MCD signal. From above results, it was concluded that both Pd capping and interface roughness induce and reenforce the perpendicular magnetic anisotropy. The large perpendicular magnetic anisotropy of Co/Pd multilayer system made by sputtering method can be well understood from our results.