• The korean journal of orthodontics
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• v.24 no.3 s.46
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• pp.709-719
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• 1994

The aim of this investigation was to identify which suing is more suitable for uprighting of the 30 degree inclined lower second molar in different situations. Between four different molar uprighting springs which were A, B, C type and T-loop spring, the author tested T-loop suing as a control material and the other springs were experimental group. Each spring was fabricated from .017' $\times$ .025' TMA wire and preactivated with 40 degree tip-back bend. Stabilizing unit included from the lower right central incisor to the lower right second premolar which were made by acrylic resin. The photoelastic overview of the lower right quadrant showed that stress concentrations were observed in its photoelastic model. The obtained results were as follows. 1. Higher concentration of compression can be seen clearly at the distal curvature than the mesial of the lower second molar when A type uprighting spring was applied, which can be used as a space regainer. 2. Higher level compression was presented at the mesial root apex area than the distal of the lower second molar in B type uprighting spring, which can be used as a space closer. 3. Areas of higher compression and tension were observed about the mesial and distal root of the lower second moalr than A and B type in C type uprighting spring, which can be used as a partial space regainer.

• Journal of Biosystems Engineering
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• v.20 no.3
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• pp.205-216
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• 1995

A fast and inexpensive approximate analysis method to predict power output characteristics of the Stilting engines in a preliminary design stage was investigated. In basic equations proposed by Walker, typical temperatures of working fluids in expansion and compression spaces were treated as those of working fluids in heater and cooler respectively. While the temperature of working fluid in the expansion space was actually lower than that of working fluid in the heater, the temperature of working fluid in the compression space was higher than that of working fluids in the cooler. In this paper, the working fluid temperature of expansion space was treated as lower than the heater temperature and that of compression space was treated as higher than the cooler temperature. Also, according to them, the power output characteristics of the Stirling engine were evaluated with respect to the GPU-3 and 4-215 Stilting engines. The following conclusions were drawn from the analysis. 1. Using the available experimental data from the GPU-3 Stirling engine, it was shown that the approximate analysis predicts the brake power with a maximum error of 19 percent at 1, 000rpm and with a minimum error of 3 percent at 2, 000rpm. 2. The approximate analysis data which for the GPU-3 Stirling engine were much closer to the experimental data than those of adiabatic 2nd order and 3rd order analysis within 1, 500rpm to 2, 500rpm. 3. The approximate analysis data which for the GPU-3 and 4-215 Stilting engines were much closer to the experimental data than those of the Beal number analysis.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.33.3-33.3
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• 2009

We report the detection of the C IV $\lambda\lambda1548$, 1551 emission line in the region of the RCW 114 nebula using the FIMS/SPEAR data. The observed C IV line intensity indicates that RCW 114 is much closer to us than HD 156385, a Wolf-Rayet star that was thought to be associated with RCW 114 in some of the previous studies. We also found the existence of a small H I bubble centered on HD 156385, with a different LSR velocity range from that of the large H I bubble which was identified previously as related to RCW 114. These findings imply that the RCW 114 nebula is an old supernova remnant which is not associated with the Wolf-Rayet star, HD 156385. Additionally, the global morphology of the C IV and $H{\alpha}$ emissions shows that RCW 114 has evolved in a non-uniform interstellar medium.

• International Journal of High-Rise Buildings
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• v.8 no.1
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• pp.49-56
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• 2019

Against the background of the rapid development of the Shanghai Metro network, this paper attempts to establish an analytical approach to evaluate the impact of multiple transport network accessibilities on commercial space use in metro station areas. Ten well-developed metro station areas in central Shanghai are selected as samples. Commercial space floor area and visitors in these areas are collected. Using ArcGIS and Spatial Design Network Analysis, the Shanghai Metro network and road network are modeled to compute diversified transport accessibilities. Evidence from land use and commercial space floor area within a 0-to-500-meter buffer zone of stations is consistent with location and land-use theory: commercial land use is concentrated closer to stations. Correlation analysis suggests that hourly visitors to the shopping mall are mainly influenced by metro network accessibility, while retail stores and restaurants are affected by both metro and pedestrian accessibility.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.57.3-57.3
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• 2021

99942 Apophis is an Sq-type Potentially Hazardous Asteroid (PHA) with an estimated diameter of 370 m. It will approach the Earth down to 31,000 km from the surface during the encounter on April 13, 2029 UT, which is closer than geostationary satellites. This once-in-a-20,000 year opportunity would further expand our knowledge on the physical and dynamical processes which are expected to occur due to the gravitational tidal forces when an asteroid encounter with a planet. It will also provide an opportunity to promote great knowledge of the science of planetary defense. The science goal of the Apophis mission is to global-map the asteroid before and after the Earth's approach. In this talk, we will present scientific objectives, and briefly introduce instruments and operation scenarios of the mission.

• Journal of Astronomy and Space Sciences
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• v.38 no.3
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• pp.165-173
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• 2021

Apophis is a near-Earth object with a diameter of approximately 340 m, which will come closer to the Earth than a geostationary orbit in 2029, offering a unique opportunity for characterizing the object during the upcoming encounter. Therefore, Korea Astronomy and Space Science Institute has a plan to propose a space mission to explore the Apophis asteroid using scientific instruments such as a laser altimeter. In this study, we evaluate the performance metrics of a laser altimeter using a pseudorandom noise modulation technique for the Apophis mission, in terms of detection probability and ranging accuracy. The closed-form expression of detection probability is provided using the cross correlation between the received pulse trains and pseudo-random binary sequence. And the new ranging accuracy model using Gaussian error propagation is also derived by considering the sampling rate. The operation range is significantly limited by thermal noise rather than background noise, owing to not only the low power laser but also the avalanche photodiode in the analog mode operation. However, it is demonstrated from the numerical simulation that the laser altimeter can achieve the ranging performance required for a proximity operation mode, which employs commercially available components onboard CubeSat-scale satellites for optical communications.

• Korean Institute of Interior Design Journal
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• v.22 no.5
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• pp.143-151
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• 2013

As we recognize the space, humans will experience a process to synthesize elements of cognitive various methods, come to understand the environment. It is intended that on humans to recognize the space, it is intended to act directly under study how to recognize. Humans can know that the determining action based on the values and physical condition, based on the space in which they have been recognized, there are differences in the behavior of the human as a result. Social and arrangement of components - physical region that is cultural difficulties constitute experience specific areas therein. Space for human activities and human, can know that it is not a memory of human behavior, to have a closer relationship with human perception. That is, the description will be aware of the space via the perceptual phenomenon of man due to physical elements performed in the space, what acts about what happens. Through an understanding of the potential for this, and emotion space production consisting only of physical visual element future, and use act of the area to be expressed from his recognition, through the expansion of the perceptual elements, diverse experience richer and more it is a case where deemed necessary access space configuration capable of a broad depth study of this portion is happening, in order to constitute a space, a new interpretation for human behavior is progressing.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.64.1-64.1
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• 2015

In the present study, we examine the dependence of solar proton peak flux at SOHO and STEREO on 3-D CME parameters (radial speed, angular width, and longitudinal angular separation between its source region and the magnetic footpoints of spacecraft). For this we consider 38 proton enhancements of 16 SEP events observed by SOHO, STEREO-A, and/or B from 2010 August to 2013 June. As a result, we find that the enhancements are strongly dependent on these three parameters. The correlation coefficient between proton peak flux and CME speed is about 0.42 for the cases the footpoints are located inside the lateral boundaries of angular widths, while there is no correlation for the events outside the boundaries. The correlation coefficient between peak flux and angular separation is -0.51. We find that most of strong proton events occur when their angular separations are closer to zero, supporting that most of the proton fluxes are generated near the CME noses rather than their flanks.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.61.4-61.4
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• 2019

The key science goal of the KMTNet Supernova Program (KSP) is to detect and study the early explosions of supernovae using one fifth of the KMTNet time. The BVI-band observations of the nearby target fields mostly closer than 30 Mpc distance and the follow-up spectroscopy provide valuable information on the early phase of the supernovae. These data can also be used for the studies of optical transients such as novae, dwarf novae, variable stars, and active galactic nuclei. Stacked images of several hundred images obtained from the time domain observations can be used for the search of low surface brightness galaxies reaching $28mag\;arcsec^{-2}$. Results and status of the KSP including ${\geq}20$ infant supernovae and ${\geq}100$ faint dwarf galaxies will be presented in this talk.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.10
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• pp.853-861
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• 2012

This paper considers one of the explicit guidance algorithms, which has been proposed by Jaggers, to determine the closed-loop guidance algorithm for upper stages of a 3-staged space launch vehicle. Its commanded thrust vector is closer to the optimal solution when compared with that obtained by using the well-known Powered Explicit Guidance (PEG), which has been developed through the Space Shuttle program. Its performance is evaluated here by applying for guidance of the launcher during the second and third stages. Furthermore, to generate more precise guidance commands, it is attempted not to use the approximate formulas for the derivation of the original guidance law, and it is shown that performance is improved in comparison with the original.