• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2012.05a
• /
• pp.177-178
• /
• 2012

In this experiment, post-nitriding treatment has been performed at $400^{\circ}C$ on AISI 316 stainless steel which is plasma carburized previously at $430^{\circ}C$ for 15 hours. Plasma nitriding was implemented on AISI 316 stainless steel at various gas compositions (25% N2, 50% N2 and 75% N2) for 4 hours. Additionally, during post nitriding Ar gas was used with H2 and N2 to observe the improvement of treatment. After treatment, the behavior of the hybrid layer was investigated by optical microscopy, X-ray diffraction, and micro-hardness testing. Potentiodynamic polarization test was also used to evaluate the corrosion resistance of the samples. Meanwhile, it was found that the surface hardness increased with increasing the nitrogen gas content. Also small percentage of Ar gas was introduced in the post nitriding process which improved the hardness of the hardened layer but reduces the corrosion resistance compared with the carburized sample. The experiment revealed that AISI 316L stainless steel showed better hardness and excellent corrosion resistance compared with the carburized sample, when 75% N2 gas was used during the post nitriding treatment. Also addition of Ar gas during post nitriding treatment were degraded the corrosion resistance of the sample compared with the carburized sample.

• 사회경제평론
• /
• no.38
• /
• pp.199-240
• /
• 2012

According to the Post Keynesian endogenous money theory, money is created by the bank deposit which is dependent on the banks' supply of loan. And the demand for loans is dependent on investment by firms. In the money creating process, real value(or investment) and money are connected with banks' credit. In this paper, we investigated Keynes and Post Keynesian endogenous money theory with critical reviews of Hwang (2005). We came to three conclusions. First, Post Keynesian endogenous money theory is based on Keynes' theory. Second, Keynes' endogeneity of money is essentially different from that of Wicksellian. Third, focusing on the differences of the starting point of the arguments not on the conclusions, two Post Keynesian views, namely horizontalists and structuralists are compatible with liquidity preference theory in the Keynes' system.

• Advances in nano research
• /
• v.10 no.5
• /
• pp.423-435
• /
• 2021

This paper examines the thermal post-buckling behaviors of graphene-reinforced metal matrix composite (GRMMC) laminated cylindrical panels which possess in-plane negative Poisson's ratio (NPR) and rest on an elastic foundation. A panel consists of GRMMC layers of piece-wise varying graphene volume fractions to obtain functionally graded (FG) patterns. Based on the MD simulation results, the GRMMCs exhibit in-plane NPR as well as temperature-dependent material properties. The governing equations for the thermal post-buckling of panels are based on the Reddy's third order shear deformation shell theory. The von Karman nonlinear strain-displacement relationship and the elastic foundation are also included. The nonlinear partial differential equations for GRMMC laminated cylindrical panels are solved by means of a singular perturbation technique in associate with a two-step perturbation approach and in the solution process the boundary layer effect is considered. The results of numerical investigations reveal that the thermal post-buckling strength for (0/90)_5T GRMMC laminated cylindrical panels can be enhanced with an FG-X pattern. The thermal post-buckling load-deflection curve of 6-layer (0/90/0)_S and (0/90)_3T panels of FG-X pattern are higher than those of 10-layer (0/90/0/90/0)_S and (0/90)_5T panels of FG-X pattern.

• Journal of Ecology and Environment
• /
• v.41 no.3
• /
• pp.93-98
• /
• 2017

Background: Although phytoremediation is a promising method for pollution control, biomass produced by the remediation process must be managed; otherwise, it will eventually return to the environment and cause secondary pollution. Therefore, research and policy development for the post-remediation management of biomass are both required. Results: While there are many published studies of phytoremediation, research into post-remediation management is very limited. Therefore, a new study using biomass as a co-composting material was conducted and showed positive effects on soil characteristics and plant performance. However, despite its potential, research and policies to promote this form of management are still lacking. Conclusions: We suggest public engagement in support of "Post-phytoremediation management" legislation that stipulates management of biomass after phytoremediation, promotes recycling of biomass with known environmental risks, and includes specific policies developed for managers. Further research to support and inform such policies and laws is also required.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.10
• /
• pp.930-934
• /
• 2006

This paper reports a change of carbon nanotubes(CNTs) properties by post-treatment process after growth of CNTs. CNTs were treated by thermal method and solution method, and then investigated in detail using field emission scanning electron microscopy(FE-SEM), high resolution transmission scanning electron microscopy(HR-TEM), RAMAN spectroscopy, and Fourier Transform Infrared Spectrometer (FT-IR). FT-IR spectra showed that the amount of hydroxyl generated on surface of CNTs were changed with post-treatment condition. FE-SEM and TEM images were shown CNTs diameter and density variations were dependent with their treatment conditions. RAMAN spectroscopy was shown that carbon nanotubes structure vary with treatment conditions.

• Journal of Integrative Natural Science
• /
• v.9 no.4
• /
• pp.275-280
• /
• 2016

Intensity modulated photovoltage spectroscopy (IMVS) analysis of organic solar cells (OSCs) with a bulk-heterojunction (BHJ) film composed of P3HT and $PC_{61}BM$ was performed. The dynamic response of charge recombination by the post-annealing approach in $P3HT/PC_{61}BM$ BHJ solar cells characterized by IMVS demonstrated that post-annealing reduced the recombination of electron carriers in the device. The recombination times of $P3HT/PC_{61}BM$ BHJ solar cells post-annealed at room temperature, 80, 120, and $140^{\circ}C$ were 0.009, 0.020, 0.024, and 0.030 ms, respectively, at a short-circuit current of 0.18 mA. The results indicated that the IMVS analysis can be effectively used as powerful.

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.5
• /
• pp.44-52
• /
• 1996

A procedure predicting warpage and post-deformation due to heat resistance test is presented. The procedure is applied to the injection molding processes of automotive plastic components, which are the door trim and the instrument pannel. The warpage of products is obtained from the residual stress after filling, packing and cooling process, and the post deformation due to the heat resistance test is calculated in the structural analysis of the product at the ejection temperature with the initial condition of residual stress, the boundary conditions and heat resistance conditions. The analyses give some useful guide lines in the design of automotive plastic parts which should satisfy heat resistance regulation.

• Journal of the Korean Home Economics Association
• /
• v.41 no.11
• /
• pp.201-214
• /
• 2003

The purpose of this research was to develop the education program for post-divorce adjustment and to evaluate effectiveness of the program. This program was consisted of eight sessions and applied to divorced parents. It was focused for the understanding of grief processes for adults, recovery by forgiveness, children's responses and coping strategies to divorce, open minded relationship between parents and children, and enhancement of self-esteem to be healthy single parent. Results of paired t-test showed that there were significant differences between pre-test and post-test, and the effectiveness remained until follow-up. In conclusion, this program was thought to be effective for improving self-esteem, divorce coping competency and minimizing of the depressions. Continual education is thought to be necessary for maintaining of the effectiveness to the divorced parents.

• Journal of Sensor Science and Technology
• /
• v.18 no.6
• /
• pp.441-448
• /
• 2009

Magnesia partially stabilized zirconia(Mg-PSZ) solid electrolytes for an improvement of thermal shock resistance, which is suitable for the measurement of oxygen activity in a molten steel, were prepared by post-thermal aging treatment. The steelmaking oxygen sensor elements were formed by an injection molding method, sintered at $1650^{\circ}C$, and then thermal aged ranged from 1250 to $1400^{\circ}C$. Sintered density and porosity were decreased as increasing the magnesia content in a zirconia-magnesia solid solution. Fractions of cubic phase to the synthesized Mg-PSZ solid electrolytes were ranged from 13.13 to 79.54.% after post-thermal aging treatment. Very dense microstructure without voids in the grains was obtained by the post-thermal aging process. Fine tetragonal phase crystallites precipitated on the cubic surface during post-thermal aging up to $1300^{\circ}C$ improve a thermal shock resistance and reappearance of electro motive force(EMF) curve.

• Journal of the Korean Home Economics Association
• /
• v.36 no.2
• /
• pp.145-160
• /
• 1998

This study was designed to investigate purchasing and post-purchase behaviors of middle-aged wives in buying townwears, an well as to examine socio-demographic variables, physical variables, psychological variables, and their influences on. The data included 374 housewives in Seoul and Pusan. Statistics used for data analysis were Frequencies, Means, Standard Deviation, t-test, ANOVA, Pearson's Correlation. The major finding are as follows: 1. The level of post-purchase satisfaction marked higher than middle point. 2. Post-purchase satisfaction differed significantly in income, health-state, identity, stress perceptivity, income satisfaction, sense of comparison, and propensity to consume.