• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2011.09a
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• pp.3-21
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• 2011

Laboratory experiments and numerical simulations using Particle Flow Code (PFC2D) were performed to study the effects of joint separation and joint overlapping on the full failure behavior of rock bridges under direct shear loading. Through numerical direct shear tests, the failure process is visually observed and the failure patterns are achieved with reasonable conformity with the experimental results. The simulation results clearly showed that cracks developed during the test were predominantly tension cracks. It was deduced that the failure pattern was mostly influenced by both of the joint separation and joint overlapping while the shear strength is closely related to the failure pattern and its failure mechanism. The studies revealed that shear strength of rock bridges are increased with increasing in the joint separation. Also, it was observed that for a fixed cross sectional area of rock bridges, shear strength of overlapped joints are less than the shear strength of non-overlapped joints.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.5
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• pp.598-606
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• 2013

After the missile is launched, the umbilical connector should be separated from it without any physical interference. The umbilical separation device, for this purpose, was developed by means of new concept. Using the investigation of various methods to separate the umbilical connector, a suitable method was selected and a corresponding device was designed and manufactured. To ensure the performance of the developed device, numerical analysis and performance test were conducted and correction was followed. The umbilical separation device was applied to real system operation test and its operation performance was tested. In consequence, several problems were founded, however, good results were generally obtained.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.132-135
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• 2001

Cryogenic air separation unit(ASU) was developed about 100 year ago in Europe. However, because there is not any ability of process design or manufacturing of ASU in Korea, many ASUs come from advanced countries every year. The purpose of this study is the development of cryogenic air separation unit by our own ability, especially cold box for nitrogen production. On this study, we developed the computer program for physical properties of gases and process simulation. We also did process design and manufactured of cold box, including air separation column, liquid air heat exchanger and condenser. The result of cold box test was successful.

• Korean Membrane Journal
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• v.7 no.1
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• pp.51-57
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• 2005

Pervaporation with a membrane is one of the economic technologies for separation of liquid mixtures including organic/water mixtures. The ZSM-5 membrane was used fur pervaporation of dichloromethane, 1,2-dichloroethane and trans-1,2-dichloroethylene from their aqueous solutions since its physical property shows very hydrophobic. ZSM-5 crystals were hydrothermally grown and deposited on the inside of a porous sintered stainless steel tube by the secondary growth method. Fluxes of dichlorinated organic compounds were observed to be $50{\~}429\;g/m^2/h$ while separation factors were $15{\~}320$ depending on a mole fraction of a dichlorinated organic compound in a feed solution ranged from 0.0001 to 0.001 mole fraction and the operation temperature between $25^{\circ}C\;and\;35^{\circ}C$.

• Proceedings of the Korean Environmental Health Society Conference
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• 2001.11a
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• pp.64-69
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• 2001

The present work provides a result from the preliminary experiment for hydrocyclone technology. In this work, local lake sediments and waste coal fly ash were used as test samples, prior to the application of hydrocyclone technology to the waste sludge thickening. A few cyclones based on the Rietema standard geometry were prepared. Chemical analysis of the sediments showed that more organic contaminants were in smaller particles. The experimental tests further showed that physical characteristics of particles, configuration of the cyclone and operation condition would affect the separation efficiency. The current results showed that small size cyclones might improve the separation and concentration of the lake sediments, and higher inlet velocity would increase the concentration rate of under flow and absolute concentration of sediment particles.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.103-105
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• 2003

A chiral stationary phase (CSP) was synthesized by the modification of the chitosan using N-nicotinoyl phenylalanine and 3, 5-dimethylphenylisocyanate . The CSP based on the chitosan was then characterized in terms of their chemical structure and physical properties. To test its performance as a CSP, the silica powder with 5 ${\mu}{\textrm}{m}$ of diameter were coated with the CSP to pack a column for High Performance Liquid Chromatograph (HPLC). Using the packed column, several racemates were tried to separate under various separation conditions with different compositions of eluents.

• Membrane Journal
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• v.12 no.3
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• pp.121-142
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• 2002

The $CO_2$ emission is the largest contribute for the green house effect. Among the existing chemical separation processes, the membrane separation technology is(/will be) the most potential process for $CO_2$, separation from flue gas. Based on the solution-diffusion theory and physical properties of carbon dioxide/nitrogen and the permeation data in the literature, the relationships between physico-chemical structures of polymeric membrane materials and the perm-selectivities for $CO_2$/$N_2$ gases were described in detail. The progress of membrane module and process development was introduced briefly. Finally, the worldwide research activity including South Korea's for carbon dioxide separation by membrane technology were introduced through the survey of papers and technical reports published.

• Korean Journal of Child Studies
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• v.13 no.1
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• pp.16-37
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• 1992

The purpose of this study was the development of a scale to assess maternal anxiety after mother-child separation. Subjects consisted of 384 mothers who had children from 6 to .36 months of age. A questionnaire consisting of eighty Likert-type items and Spielberger's(1970) State Anxiety Scale were administered to mothers and data were analyzed using item analysis. factor analysis. multiple regression. Cronbach's ${\alpha}$. Pearson's correlation and F-test. Sixty of the eighty items were significant and deemed acceptible through item discrimination method with indices ranging from. 32 to .95. Factor analytic procedures have selected 54 items of the 60-item scale and supported a 5-factor solution. The subscales labeled 'Maternal Separation Anxiety'. 'Perception of Separation Effects on the Child', 'Desire for Physical Cuddling and Closeness'. 'Attitudes toward the Value or Importance of Exclusive Maternal Care' and 'Employment-related Separation Concerns,' Finally. a multiple regression analysis conducted to reduce the length of the scale yielded a 39-item form for the Maternal Separation Anxiety Scale(MSAS). Internal consistency of the MSAS was high(Cronbach's ${\alpha}$ =.85). The correlation of the MSAS with the Spielberger's State Anxiety measure yielded a coefficient of .36, revealing a moderate and positive relationship.

• Current Applied Physics
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• v.18 no.12
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• pp.1558-1563
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• 2018

We demonstrate improved surface pit and phase separation in thick InGaN grown on a GaN/Si (111) substrate, using plasma-assisted molecular beam epitaxy with an indium modulation technique. The formation of surface pit and compositional inhomogeneity in the InGaN epilayer are investigated using atomic force microscopy, scanning electron microscopy and temperature-dependent photoluminescence. Indium elemental mapping directly reveals that poor compositional homogeneity occurs near the pits. The indium-modulation epitaxy of InGaN minimizes the surface indium segregation, leading to the reduction in pit density and size. The phase separation in InGaN with a higher pit density is significantly suppressed, suggesting that the pit formation and the phase separation are correlated. We propose an indium migration model for the correlation between surface pit and phase separation in InGaN.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.33 no.2
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• pp.48-54
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• 2022

Objectives: Among adolescent development tasks, being independent of parents is an essential process for emotional and physical separation. There are many conflicts of separation and individuation between parents and adolescents; however, most clinicians explore the process of separation and individuation only from adolescents' perspective. Whether simultaneously or sequentially, separation-individuation occurs between adolescents and parents, respectively. The authors have already introduced the theory of synchronized individuation in a clinical case to explain the concept of this intersubjective phenomena. This study also attempts to prove the synchronized individuation theory through the interaction of characters in a movie and a fairy tale. Methods: The authors present the basis for the theory of synchronized individuation of adolescence through the growing process of Mason Junior, the main character of the movie "Boyhood," and from the process of the separation of a hen, Sprout, and an orphaned duckling in "The hen who dreamed she could fly." Results: Synchronized individuation was developed and observed from Mason, the son's perspective in "Boyhood," and Sprout, the mother's subjective perspective in the story of the hen. Conclusion: Increasing conflict and mutual impact in the relationship between adolescents and parents, ambivalent feelings for separation, selective identification of each other, mutual respect through mutual recognition, and role changes in relationship position were confirmed. Sons and mothers were individualized with synchronization.