• Geomechanics and Engineering
• /
• v.36 no.1
• /
• pp.51-69
• /
• 2024

Currently, composite lining mountain tunnels in China are generally classified based on the [BQ] method for the surrounding rock grade. Increasingly, tunnel field construction is replicated indoors for scale down model tests. However, the development of analogous materials for model tests of composite lining tunnels with different surrounding rock grades is still unclear. In this study, typical Class III and V surrounding rock analogous materials and corresponding composite lining support materials were developed. The whole processes of excavation-support dynamics of the mountain tunnels were simulated. Data on the variation of deformations, contact pressures and strains on the surrounding rock were obtained. Finally, a comparative analysis between model tests and numerical simulations was performed to verify the rationality of analogous material development. The following useful conclusions were obtained by analyzing the data from the tests. The main analogous materials of Class III surrounding rock are barite powder, high-strength gypsum and quartz sand with fly ash, quartz sand, anhydrous ethanol and rosin for Class V surrounding rock. Analogous materials for rockbolts, steel arches are replaced by aluminum bar and iron bar respectively with both shotcrete and secondary lining corresponding to gypsum and water. In addition, load release rate of Class V surrounding rock should be less than Class III surrounding rock. The fenestration level had large influence on the load sharing ratio of the secondary lining, with a difference of more than 30%, while the influence of the support time was smaller. The Sharing ratios of secondary lining in Class III surrounding rock do not exceed 12%, while those of Class V surrounding rock exceed 40%. The overall difference between the results of model tests and numerical simulations is small, which verifies the feasibility of similar material development in this study.

• Nuclear Engineering and Technology
• /
• v.38 no.5
• /
• pp.437-442
• /
• 2006

European Material Test Reactors (MTRs) have provided essential support for nuclear power programs over the last 40 years. MTRs are now ageing in Europe and they cannot ensure the securing of experimental capability for the next decades. In this context, a new Material Testing Reactor, named Jules Horowitz Reactor -JHR-, operated as an international user-facility, is under development in Europe. The European MTRs context and the JHR objectives and status will be presented. Emphasis will be put on experiments in the field of nuclear fuels and materials irradiation which are developed in the framework of European and international collaboration.

• Journal of the Korea Society of Computer and Information
• /
• v.21 no.3
• /
• pp.137-143
• /
• 2016

This study is to test moderating effects of North Korean Refugees' coping styles in the causal relation between social support and psychological wellbeing and suggest policy implications for helping social adjustment of North Korean Refugees. For this study, 100 North Korean Refugees were sampled and surveyed. The analytical result of this study showed that the degree of psychological wellbeing was highest among the refugees of the entire families migration. Also, this study showed that the causal relationship between social support and psychological wellbeing was not significant, and moderating effects of emotional support and appraisal support were significant, while moderating effects of material support and informative support were not significant. In this study, we suggested some policy implications basing on this analytical results.

• Korean Journal of Child Studies
• /
• v.26 no.5
• /
• pp.311-330
• /
• 2005

The purpose of this study was to examine the paternal involvement tendency and its effect on adolescent's self-esteem for boys and girls. Subjects were 607 1st and 2nd grade middle school students in Busan. The data were analyzed by t-test, one-way Anova, Pearson's correlation, and multiple regression analysis. The results were as follows. The scores on paternal involvement were influenced by the amount of time spent with parents, 5days work a week of father, flexibility of leaving work-time of mother, regularity of holiday work of mother as well as adolescents' and fathers' sociodemographic characteristic. For boys, self-esteem was influenced by all sub-scales of paternal involvement : the leisure-life, proffering information, academic support, eveηday life, material support, discipline, and tradition-inheritance. For girls, self-esteem was influenced by leisure-life, proffering information, academic support, everyday life, and material supports.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 2001.01a
• /
• pp.224-229
• /
• 2001

When a semiconductor package is assembled, various materials such as die attach adhesive, lead frame, EMC (Epoxy Molding Compound), and gold wire are used. For better preconditioning performance, the combination between the packaging materials by studying the compatibility of their properties as well as superior packaging material selection is important. But it is not an easy task to find proper packaging material sets, since a variety of factors like package design, substrate design, substrate size, substrate treatment, die size, die thickness, die passivation, and customer requirements should be considered. This research applies case-based reasoning(CBR) technique to solve this problem, utilizing prior cases that have been experienced. Our particular interests lie in building decision support model to aid the selection of proper die attach adhesive. The preliminary results show that this approach is promising.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.6 no.1
• /
• pp.42-50
• /
• 2001

The activity of immobilized cell-support particle aggregates is influenced by physical and biochemical elements, mass transfer, and physiology. Accordingly, the mathematical model discussed in this study is capable of predicting the steady state and transient concentration profiles of the cell mass and substrate, plus the effects of the substrate and product inhibition in an immobilized cell-support aggregate. The overall mathematical model is comprised of material balance equations for the cell mass, major carbon source, dissolved oxygen, and non-biomass products in a bulk suspension along with a single particle model. A smaller bead size and higher substrate concentration at the surface of the particle, resulted in a higher supply of the substrate into the aggregate and consequently a higher biocatalyst activity.

• Journal of the Korean Ceramic Society
• /
• v.38 no.10
• /
• pp.876-880
• /
• 2001

The supported and unsupported boehmite ($\gamma$-AlOOH) membranes were prepared using a boehmite sol. The supported membrane was consisted of a porcelain support, two intermediate $\alpha-{Al_2}{O_3}$ layers, and a top boehmite membrane. XRD patterns showed that the supported top membrane had a higher $\theta-$ to $\alpha-{Al_2}{O_3}$ transformation temperature compared to the unsupported membrane. This result was also confirmed from microstructural study of the membrane. The shift in the phase transformation temperature should be explained by difference of a stress generated in the supported top membrane due to interaction between the support layers and the top membrane.

• Geomechanics and Engineering
• /
• v.9 no.2
• /
• pp.195-205
• /
• 2015

Barricade failures generally occur at the early times of paste backfill when it is fresh in the stopes. The backfill strength increases and need for barricading pressure decreases as a result of the hydration reactions. In this study, paste backfill barricades of Cayeli copper mine were investigated to design cemented mineral processing plant tailings as barricade body concrete. Paste backfill in sub-level caving stopes of the mine needs to be barricaded for only four or five days. Therefore, short term strength and workability tests were applied on several cemented tailings material designs. Barricade failure mechanisms, important points of barricade designing and details of the new concrete material are explained in this work. According to the results obtained with this experimental study, the tailings were assessed to be used in concrete applied as temporary supports such as cemented paste backfill barricades.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.3
• /
• pp.485-491
• /
• 2021

This study examined the effects of preschool teachers' social support and mindfulness on job exhaustion. The study subjects were 138 preschool teachers in OO city. As an analysis method, frequency analysis, reliability analysis, and correlation analysis were performed using the SPSS 22.0 program, and multiple regression analysis was performed on the causal relationship between the variables. An examination of the effect of social support on preschool teachers on job exhaustion found that the material support factor, a sub-factor of social support, had a negative effect (-) on job exhaustion. Second, the sub-factors of mindfulness, decentered attention, and present awareness had a significant negative effect on job exhaustion. A higher the current awareness, the decentered attention of mindfulness, and the material support factor of social support perceived by preschool teachers indicated lower job exhaustion. These results provide the basic data for the preparation of measures for reducing job exhaustion of preschool teachers.

• 한국생물공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.456-462
• /
• 2005

The objective of this study was to develop a removal process by which $H_2S$ could be biologically removed from the odoriferous gases generated in the waste food recycling process. In order to develop this process we were first required to select a proper biofilter support protocol. When the selected biofilter equipment was then tested suing a synthetic odoriferous gas containing 600 ppm of $H_2S$, we noted a maximal removal rate of 658 $g-H_2S/m^3{\cdot}hr$, using polypropylene fibrils as supporting materials. Under identical experimental conditions, we obtained a value of 411.2 $g-H_2S/m^3{\cdot}hr$, using polyurethane as a support material. We also conducted a trial in which volcanic stone was utilized as a support material, and in this trial, we logged a maximal 105.1 $g-H_2S/m^3{\cdot}hr$ removal rate. As the result of our experiments, we concluded that polypropylene fibrils constituted the ideal material for the removal of $H_2S$ gas via biological treatment.