• Journal of the Korean Applied Science and Technology
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• v.26 no.2
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• pp.191-198
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• 2009

We have tested the stability of paeoniflorin, a new cosmetic ingredient, extracted from the roots of Paeoniae lactiflora. The stability of aqueous paeoniflorin solution at pH 3, 5 and 7 varied by adding buffer solution was tested at $0^{\circ}C,\;25^{\circ}C,\;40^{\circ}C,\;and\;65^{\circ}C$. The test was performed with or without UV light. The solution of paeoniflorin was stable at pH 3.0, however, the recovery rate of paeoniflorin was 40% at pH 7.0. The stability of paeoniflorin solution was decreased as the pH of paeoniflorin solution was increased by pH 7.0. The effect of storage temperature of paeoniflorin solution shows that the stability of paeoniflorin solution was decreased as the temperature was increased. The stability of paeoniflorin was rather good under UV light than the condition given above $40^{\circ}C$. The stability of paeoniflorin in W/O emulsions shows similar pattern to that of aqueous solution.

• Geomechanics and Engineering
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• v.10 no.1
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• pp.59-76
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• 2016

The non-linear Hoek-Brown failure criterion has been widely accepted and applied to evaluate the stability of rock slopes under plane-strain conditions. This paper presents a kinematic approach of limit analysis to assessing the static and seismic stability of three-dimensional (3D) rock slopes using the generalized Hoek-Brown failure criterion. A tangential technique is employed to obtain the equivalent Mohr-Coulomb strength parameters of rock material from the generalized Hoek-Brown criterion. The least upper bounds to the stability number are obtained in an optimization procedure and presented in the form of graphs and tables for a wide range of parameters. The calculated results demonstrate the influences of 3D geometrical constraint, non-linear strength parameters and seismic acceleration on the stability number and equivalent strength parameters. The presented upper-bound solutions can be used for preliminary assessment on the 3D rock slope stability in design and assessing other solutions from the developing methods in the stability analysis of 3D rock slopes.

• Journal of Korean Physical Therapy Science
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• v.19 no.2
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• pp.63-71
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• 2012

Purpose : This study aimed to acquire a basic knowledge about lumbar stability and inquire into exercise approach of pressure biofeedback unit for lumbar stability. Methods : This study was composed with reviewed theory of lumbar stability and several books and articles for exercise using pressure biofeedback unit. Results : The stability of lumbar should work symmetrical with passive, active, control subsystem in neutral zone, and local muscles should be using for stability. Especially, selective using of transverse abdominis work for lumbar stability importantly. The control of using pressure biofeedback unit may important not only examination but treatment. Conclusion : The stability of lumbar need co-contraction of specific local muscle and training for timing as well as using pressure biofeedback unit for accurate control may use for examination and therapedic approach.

• Journal of the Korean Society of Combustion
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• v.17 no.1
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• pp.22-29
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• 2012

The detachment stability characteristics of syngas $H_2$/CO jet attached flames were studied. The flame stability was observed while varying the syngas fuel composition, coaxial nozzle diameter and fuel nozzle rim thickness. The detachment stability limit of the syngas single jet flame was found to decrease with increasing mole fraction of carbon monoxide in the fuel. In hydrogen jet flames with coaxial air, the flame detachment stability was found to be independent of the coaxial nozzle diameter. However, velocities of appearance of liftoff and blowout velocities of lifted flames have dependence. At lower fuel velocity range, the critical coaxial air velocity leading to flame detachment increases with increasing fuel jet velocity, whereas at higher fuel velocity range, it decreases. This increasing-decreasing non-monotonic trend appears for all $H_2$/CO syngas compositions (50/50~100/0% $H_2$/CO). To qualitatively understand the flame behavior near the nozzle rim, $OH^*$ chemiluminescence imaging was performed near the detachment limit conditions. For all fuel compositions, local extinction on the rim is observed at lower fuel velocities(increasing stability region), while local flame extinction downstream of the rim is observed at higher fuel velocities(decreasing stability region). Maximum values of the non-monotonic trends appear to be identical when the fuel jet velocity is normalized by the critical fuel velocity obtained in the single jet cases.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.4
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• pp.598-613
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• 2013

This paper deals with the dynamic effect of pipeline installation and embedment for the on-bottom stability design of offshore pipelines on soft clay. On-bottom stability analysis of offshore pipelines on soft clay by DNV-RP-F109 (DNV, 2010) results in very unreasonable pipe embedment and concrete coating thickness. Thus, a new procedure of the on-bottom stability analysis was established considering dynamic effects of pipeline installation and pipe-soil interaction at touchdown point (TDP). This analysis procedure is composed of three steps: global pipeline installation analysis, local analysis at TDP, modified on-bottom stability analysis using DNV-RP-F109. Data obtained from the dynamic pipeline installation analysis were utilized for the finite element analysis (FEA) of the pipeline embedment using the non-linear soil property. From the analysis results of the proposed procedure, an optimum design of on-bottom stability of offshore pipeline on soft clay can be achieved. This procedure and result will be useful to assess the on-bottom stability analysis of offshore pipelines on soft clay. The analysis results were justified by an offshore field inspection.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.2
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• pp.280-287
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• 2011

The purpose of this study is to analyze that ordinary housing stability policy determines the impact on housing prices. I got a conclusion such as the result next which carried out proof analysis for this. First, as a result of the Granger Causality Test, the house market of all areas appeared by affecting ordinary housing stability policy. Second, the shock reaction shows the reaction of the department (-) in all areas and ordinary housing stability policy appeared to be contributed to some extent house market stability. Third, as a result of having analyzed Logit Regression Analysis, ordinary housing stability policy appeared to considerable effects house market stability except Kangnam area of the Roh Moo-hyun government.

• Transactions on Electrical and Electronic Materials
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• v.6 no.1
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• pp.29-32
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• 2005

Chemical mechanical polishing is an essential process in the production of copper-based chips. On this work, the stability of hydrogen peroxide ($H_{2}O_{2}$) as an oxidizer of copper CMP slurry has been investigated. $H_{2}O_{2}$ is known as the most common oxidizer in copper CMP slurry. But $H_{2}O_{2}$ is so unstable that its stabilization is needed using as an oxidizer. As adding KOH as a pH buffering agent, stability of $H_{2}O_{2}$ decreased. However, $H_{2}O_{2}$ stability in slurry went up with putting in small amount of BTA as a film forming agent. There was no difference of $H_{2}O_{2}$ stability between pH buffering agents KOH and TMAH at similar pH value. Addition of $H_{2}O_{2}$ in slurry in advance of bead milling led to better stability than adding after bead milling. Adding phosphoric acid resulted in the higher stability. Using alumina C as an abrasive was good at stabilizing for $H_{2}O_{2}$.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.167-175
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• 2006

Directional stability is important performance in vehicle and tire design. The current methods to analyze this is generally based on linear concept. Using the existing concept, it cannot realistically explain the subjective assessment at all because it is hard to practically represent the nonlinear behaviour of a complex vehicle system in reality. In this paper, new method to analyze directional stability is introduced. At first, directional stability of vehicle is categorized into yaw, rear axle, and roll stability. In order to objectify these items, driver perceptual parameters based on subjective assessment are used. Using the perceptual parameters, it can successfully explain the transient maneuver of vehicle and extract objective parameters for directional stability. Finally, these objective parameters are successfully validated through two handling tests, lane change and severe lane change. The correlation results show that there exists a good correlation between subjective assessment and the proposed objective parameters.

• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.1
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• pp.1-11
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• 2000

Dental temporary resin should have adequate strength and similar esthetics as natural teeth. Recently esthetics has become a high priority in clinical dentistry. Thus the evaluation of color stability of dental temporary resin has become an important part in dental research. The purpose of this study was to evaluate the difference in color stability of 3 resins($Snap^{(R)}$, Temporary bridge $resin^{(R)}$, Trim $II^{(R)}$) according to polymerizing methods and stainning. The resins were divided into groups by 2 types of polymerizing methods ( air or pressure and heat curing) The resins were dyed with coffee, chlorhexidine and artificial saliva and then the color stability was evaluated with a spectrophotometer(CM-503i, Minolta, Japan). The results were as follows ; 1. In the color stability according to polymerizing method, pressure and heat polymerizing method was higher than air polymerizing method. 2. The color stability according to staining fluid decreased in the order of I, II, III group, there was significant difference among the groups of staining fluid. 3. The color stability according to resins decreased in the order of $Snap^{(R)}$, Trim $II^{(R)}$, Temporary Bridge $resin^{(R)}$, The $Snap^{(R)}$ resin was highest color stability, there was significant difference among the 3 resins.

• Journal of Powder Materials
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• v.25 no.5
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• pp.395-401
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• 2018

The improvement of dispersion stability for the primary polishing slurry in a CMP process is achieved to prevent defects produced by agglomeration of the slurry. The dispersion properties are analyzed according to the physical characteristics of each silica sol sample. Further, the difference in the dispersion stability is confirmed as the surfactant content. The dispersibility results measured by Zeta potential suggest that the dispersion properties depend on the content and size of the abrasive in the primary polishing slurry. Moreover, the optimum ratio for high dispersion stability is confirmed as the addition content of the surfactant. Based on the aforementioned results, the long-term stability of each slurry is analyzed. Turbiscan analysis demonstrates that the agglomeration occurs depending on the increasing amount of surfactant. As a result, we demonstrate that the increased particle size and the decreased content of silica improve the dispersion stability and long-term stability.