• The korean journal of orthodontics
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• v.26 no.6
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• pp.717-721
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• 1996

With conventional orthodontics, it was difficult for the anchorage segments of the wire to be engaged passively in the brackets even with complicated bending. To overcome this limitation, a kind of indirect bonding, "passive bracketing", has been developed. The present article shows laboratory and clinical procedures of the passive bracketing

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.80-83
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• 2003

Transcribability of pit or land groove structures in replicating an optical disk substrate greatly affects the performance of a high-density optical disk. However, a solidified layer, generated during the polymer filling, deteriorates transcribability because the solidified layer prevents the polymer melt in filling the sub-micro patterns. Therefore, the development of the solidified layer during filling stage of injection molding must be delayed. For this delay, passive heating by insulation layer has been used. In the present study, to examine the development of the solidified layer delayed by passive heating, the flow of polymer melt with passive heating was analyzed. Passive heating markedly delayed the development of the solidified layer, reduced the viscosity of the polymer melt, and increased the fluidity of the polymer melt in the vicinity of the stamper surface with the sub-micro patterns. As a result, we predict that passive heating can improve transcribability of an optical disk substrate. To verify our prediction, we fabricated an optical disk substrate by using passive heating of a mold and measured the transcribability.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.1
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• pp.35-43
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• 2016

PURPOSE: The purpose of this study was to investigate the effects of passive stretching exercises of the scalene muscles known as respiratory accessory muscles, on forced vital capacity. METHODS: Ten of the participants were randomly selected as an experiment group to perform passive stretching exercises on the scalene muscles. Ten additional students were selected randomly as a control group. The forced vital capacity was assessed by using a digital spirometer (Pony FX, COSMED Inc, Italy) both before and after the passive stretching exercises were performed. Subsequently, passive stretching exercises of the scalene muscles were performed in the experimental group. There were no interventions to the control group. RESULTS: As for the forced vital capacity (FVC), the experiment group showed significant increase in items of forced vital capacity (FVC), forced expiratory volume in 1 second ($FEV_1$), peak expiratory flow (PEF), forced expiratory volume in 1 second/vital capacity ($FEV_1/VC$), and maximal expiratory flow 75%(MEF 75%) after the scalenemuscles passive stretching exercises were performed. The control group, however, showed no change. CONCLUSION: This study demonstrated that passive stretching exercises of the scalene muscles could be helpful for forced vital capacity improvement.

• Journal of the Korean Solar Energy Society
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• v.30 no.4
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• pp.22-28
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• 2010

This study analyzed the performance of passive solar system for office building. A unit model of the passive solar system was proposed in order to predict its performance under varying parameters and Seoul weather date. Steady state heat transfer equations were set up using a energy balanced equations and solved using a inverse matrix method. Numerical simulation program to analyze system was developed by using MATLAB. As the results, the passive solar system performance of office building was determined by the insolation and the outdoor air temperature. Also the passive solar system indicate 6.7~16.2% of annual average efficiency. In the comparison with other systems of the conventional wall, mass wall could reduce the heating loads of 7.1% and trombe wall could reduce heating loads of 11.5%. Through this study, performance of passive solar system for office building was verified by numerical method. Consequently, the passive solar system could operate an important role as the alternative for saving energy consumption of office building, and the additional studies should be made through the experimental method for the commercialization.

• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.360-372
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• 2017

Many advanced reactor designs rely on passive systems to fulfill safety functions during accident sequences. These systems depend heavily on boundary conditions to induce a motive force, meaning the system can fail to operate as intended because of deviations in boundary conditions, rather than as the result of physical failures. Furthermore, passive systems may operate in intermediate or degraded modes. These factors make passive system operation difficult to characterize within a traditional probabilistic framework that only recognizes discrete operating modes and does not allow for the explicit consideration of time-dependent boundary conditions. Argonne National Laboratory has been examining various methodologies for assessing passive system reliability within a probabilistic risk assessment for a station blackout event at an advanced small modular reactor. This paper provides an overview of a passive system reliability demonstration analysis for an external event. Considering an earthquake with the possibility of site flooding, the analysis focuses on the behavior of the passive Reactor Cavity Cooling System following potential physical damage and system flooding. The assessment approach seeks to combine mechanistic and simulation-based methods to leverage the benefits of the simulation-based approach without the need to substantially deviate from conventional probabilistic risk assessment techniques. Although this study is presented as only an example analysis, the results appear to demonstrate a high level of reliability of the Reactor Cavity Cooling System (and the reactor system in general) for the postulated transient event.

• Transactions of Materials Processing
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• v.13 no.1
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• pp.39-44
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• 2004

Transcribability of pit or land groove structures in replicating an optical disk substrate greatly affects the performance of a high-density optical disk. However, a solidified layer, generated during the polymer filling, deteriorates transcribability because the solidified layer prevents the polymer melt from filling the sub-micro patterns. Therefore, the development of the solidified layer during filling stage of injection molding must be delayed. For this delay, passive heating by insulation layer has been used. In the present study, to examine the development of the solidified layer delayed by passive heating, the flow of polymer melt with passive heating was analyzed. Passive heating markedly delayed the development of the solidified layer, reduced the viscosity of the polymer melt, and increased the fluidity of the polymer melt in the vicinity of the stamper surface with the sub-micro patterns. As a result, we predict that passive heating can improve transcribability of an optical disk substrate. To verify our prediction, we fabricated an optical disk substrate by using passive heating of a mold and measured the transcribability of an optical disk substrate.

• Journal of Mechanical Science and Technology
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• v.18 no.3
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• pp.407-418
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• 2004

Prandtl-Meyer expansion flow with homogeneous condensation is investigated experimentally and by numerical computations. The steady and unsteady periodic behaviors of the diabatic shock wave due to the latent heat released by condensation are considered with a view of technical application to the condensing flow through steam turbine blade passages. A passive control method using a porous wall and cavity underneath is applied to control the diabatic shock wave. Two-dimensional, compressible Navier-Stokes with the nucleation rate equation are numerically solved using a third-order TVD (Total Variation Diminishing) finite difference scheme. The computational results reproduce the measured static pressure distributions in passive and no passive Prandtl-Meyer expansion flows with condensation. From both the experimental and computational results, it is found that the magnitude of steady diabatic shock wave can be considerably reduced by the present passive control method. For no passive control, it is found that the diabatic shock wave due to the heat released by condensation oscillates periodically with a frequency of 2.40㎑. This unsteady periodic motion of the diabatic shock wave can be completely suppressed using the present passive control method.

• Journal of Environmental Impact Assessment
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• v.7 no.2
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• pp.83-88
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• 1998

Filter badge type sampler has not been widely used to evaluate air quality over large cities in Korea while it can be successfully used for multi-point sampling and analysis. We evaluated the passive sampler as a new tool to monitor air quality over large cities. We latticed Metropolitan Seoul into $2{\times}2Km$ to give 136 points. $NO_2$ concentrations were measured at all the points in the Spring and Summer of 1997. According to the passive sampler data, natural green zones generally recorded lower $NO_2$ concentrations than major streets and traffic congestion areas. Passive samplers with abundant 136 points gave more detailed picture of $NO_2$ distribution while auto-monitoring network did not clearly provide the characteristics of local land use. Also, passive samplers gave 15% higher values than auto-monitoring network. The correlation between the two values appears very high judging from the regression slope of 0.92 and correlation coefficient of 0.91. This study clearly demonstrates the effectiveness of the passive sampler as a tool to monitor air quality over large cities.

• Korean Institute of Interior Design Journal
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• v.18 no.6
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• pp.28-35
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• 2009

The purpose of this study is to analyze the state-of-the-art housing cases with passive cooling technologies and to explore the feasibilities for their applications in domestic housing design. Nineteen Leadership in Energy and Environmental Design housing cases from 2002 to 2007 were selected and analyzed their used passive cooling technologies. Besides traditional passive cooling technologies such as site planning according to the sun direction, the use of thermal mass, insulation, shading, below-ground spaces and ventilation, the relatively new technology trends were detected as followings; the use of high performance envelope, operable windows, and geo-thermal energy as the cooling source of heat pumps, increased areas of photovoltaic cells, and the education of the owner and tenants about the adopted passive cooling technologies in a building. Especially, the education may have not been focused in the domestic design despite of its effectiveness on the appropriate operations of passive cooling technologies. The results of this study show their positive adaptations would be beneficial to domestic housing design to reduce energy costs and have cooler housing environments in summer.

• Geomechanics and Engineering
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• v.32 no.3
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• pp.335-346
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• 2023

For structures with underground basement walls, the soil-structure-interaction between the side soil and the walls affects the response of the system. There is interest in quantifying the relationship between the lateral earth pressure and the wall displacement using p-y curves. To date, passive p-y curves in available limited studies were assumed elastic-perfectly plastic. In reality, the relationship between earth pressure and wall displacement is complex. This paper focuses on studying the development of passive p-y curves behind rigid walls supporting granular soils. The study aims at identifying the different components of the passive p-y relationship and proposing a rigorous non-linear p-y model in place of simplified elastic-plastic models. The results of the study show that (1) the p-y relationship that models the stress-displacement response behind a rigid basement wall is highly non-linear, (2) passive p-y curves are affected by the height of the wall, relative density, and depth below the ground surface, and (3) passive p-y curves can be expressed using a truncated hyperbolic model that is defined by a limit state passive pressure that is determined using available logarithmic spiral methods and an initial slope that is expressed using a depth-dependent soil stiffness model.