• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.8
• /
• pp.4068-4076
• /
• 2013

The wheel-rail interaction forces are influenced by the velocity of vehicle, wheel load, alignment (curve radius, cant etc). For the safety of track structure, it is required to evaluate the influences for track and influential factors. Recently, the HEMU 430-X, which was developed by Next Generation High-Speed Rail Development R&D Project, achieved 421.4km/h in a test run of Daegu.Busan section of the Gyeongbu high speed rail on March in 2013. In the case of additional speed-up test on Test-Bed Section(Gongju.Jeongeup: KP 100~128km Osong starting point), the analysis of track forces is required for outer rail by the increase of dynamic force and centrifugal force of vehicle. In this paper, the vehicle speed variation on HSL line is evaluated by TPS analysis considering the tractive effort of HEMU 430-X, tested running resistance and alignment of Honam HSR. And the track forces are evaluated by centrifugal force and impact factor on curved track.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.43 no.1 s.343
• /
• pp.7-12
• /
• 2006

In this study, we developed irreversible and stable micro-size ferromagnetic structures utilizing hydrogenation and electron-beam lithography processes. The compositionally modulated (CM) Fe-Zr thin films that had average compositions $Fe_XZr_{100-x}$ with $x=65-85\%$ modulation periods of similar to 1 nm, and total thicknesses of similar to 100 m were prepared. The magnetic properties of CM Fe-Zr thin films were measured using a SQUID magnetometer, VSM and B-H loop tracer. After hydrogenation, the CM films exhibited larger magnetic moment increases than similar homogeneous alloy films for all compositions and かey showed largest increase in $Fe_{80}Zr_{20}$ composition. After aging in air at $300^{\circ}K$ the hydrogenated $Fe_{80}Zr_{20}$ CM films showed much larger magnetic moment increases, indicating that they relax to a stable, irreversible, soft magnetic state. The selective hydrogenation through electron-beam lithographed windows were performed after the circle shaped windows were prepared on $Fe_{80}Zr_{20}$ CM films by electron beam lithography. The hydrogenation through electron-beam resist and W lithographic techniques give a $49\%$ magnetic moment increase. This method can be applied to nano scale structures.

• Journal of Mushroom
• /
• v.13 no.4
• /
• pp.288-293
• /
• 2015

In the structural investigation of cultivation facilities, the proportion of farmers to grown with double or triple structure were investigated 96%. It has been shown to grow with a stable cultivation facilities structure against environmental changes. The results of the analysis of the changes in the cultivation environment of Yeoju area in July-august, temperature and humidity of the external instrument shelter was $20.2{\sim}29.9^{\circ}C$ and 66.2~99.9% respectively. In the greenhouse 2 model capable of temperature environment regulation in the cultivation facility, temperature and humidity were investigated $19.3{\sim}25.7^{\circ}C$ and 81.6~99.9% respectively. Result of the survey of fruiting body characteristics and yields in the greenhous 2, pileus diameter and stipe length were investigated 66.2 and 54.1 mm, yield of mushroom and individual weight were 312 g and 26.6 g. High-temperature environment regulation shows the improvement of the quality and productivity of the mushroom. Power consumption of the air conditioning has been investigated using 56kwh/day, electricity costs were calculated 2195 won/day.

• Journal of the Korean Chemical Society
• /
• v.26 no.4
• /
• pp.195-204
• /
• 1982

Semi-empirical MO calculations, EHT, CNDO/2, MINDO/3, and MNDO met hods, were performed on various geometries of n-butane, n-alkyl radical and tetramethylene diracal (triplet) in order to compare eigenvalue and eigenvector properties with those obtained by STO-3G method. All methods predicted the same relative order of stabilities of various geometries for n-butane; geometrical preferences were found to be dominated by one-electron factor, ${\pi}$-orbital energy changes being more impotant in the semi-empirical methods. The hyperconjugative energy changes accompanying structural changes from $(n-{\sigma}{\ast})_{trans}$ to (n-{\sigma}{\ast})cis were underestimated in the EHT, CNDO/2 and MINDO/3, whereas those were overestimated in the MNDO. The net destabilizing effect of $(n-{\sigma}{\ast})_{trans}$ structure was mainly due to the large internuclear energy involved in the structure. Through-space interaction between $n_1$ and $n_2$ orbitals of diradical caused energy gap narrowing of ${\Delta}E_{sp}$ and ${\Delta}{\varepsilon}={\varepsilon}_0$-${\varepsilon}_{av}$; through-space interaction had opposing effect to that of through-bond interaction. Due to the less severe neglect of differential overlaps in the MNDO, this energy gap narrowing effect appeared amplified in the MNDO. In general orbital properties were found to be reproduced satisfactorily, but eigenvalue properties were not, in all the semi-empirical methods especially when ${\sigma}-{\sigma}{\ast}$ and n-$n-{\sigma}{\ast}$interactions were involved.

• Korean Journal of Optics and Photonics
• /
• v.15 no.4
• /
• pp.385-390
• /
• 2004

In this paper, we designed a 4-bit optical true time-delay(TTD) for phased array antennas(PAAs), which is composed of a wavelength-fixed optical source, 2 ${\times}$ 2 optical MEMS switches, and fiber-optic delay lines. A 4-bit TTD with a unit time delay difference of 6 ps for 10-GHz PAAs has been implemented. Measurement results on time delay show an error of -0.4 ps at maximum, corresponding to a radiation angle error of less than 1.63$^{\circ}$. Thus, the TTD implemented in this research performs in excellent agreement with theory. Each TTD line, composed of MEMS switches and fiber-optic delay lines, connected to the corresponding antenna element has insertion loss in between 1.36 ㏈ and 2.40 ㏈ depending upon the setup of the switches. On the other hand, the insertion loss difference between TTD lines was 0.32 ㏈ at maximum for a fixed radiation angle. The TTD structure proposed in this paper might be more reliable and economical than those previously proposed using tunable wavelength sources if proper power equalization either with gain control of RF amplifiers or variable attenuators is achieved.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.29 no.1
• /
• pp.20-35
• /
• 2017

In the case of the seabed around and under gravity structures such as submerged breakwater is exposed to a large wave action long period, the excess pore pressure will be significantly generated due to pore volume change associated with rearrangement soil grains. This effect will lead a seabed liquefaction around and under structures as a result of the decrease in the effective stress, and eventually the possibility of structure failure will be increased. The study of liquefaction potential for regular waves had already done, and this study considered for irregular waves with the same numerical analysis method used for regular waves. Under the condition of the irregular wave field, the time and spatial series of the deformation of submerged breakwater, the pore water pressure (oscillatory and residual components) and pore water pressure ratio in the seabed were estimated and their results were compared with those of the regular wave field to evaluate the liquefaction potential on the seabed quantitatively. Although present results are based on a limited number of numerical simulations, one of the study's most important findings is that a safer design can be obtained when analyzing case with a regular wave condition corresponding to a significant wave of the irregular wave.

• Korean Journal of Microbiology
• /
• v.40 no.3
• /
• pp.244-247
• /
• 2004

To investigate the effects of elevated $CO_2$ on the denitrifying bacterial community structure in a wetland soil, dynamics of bacterial community structure was explored in an artificial wetland ecosystem with one of three plant species (T. latifolia, S. lacustris, and 1. effusus) under two levels of $CO_2$(370 ppm or 740 ppm) after 110day incubation. For the analysis of bacterial community structure, functional genes such as nitrite reductase genes (nirS) were PCR-amplified followed by cloning of PCR products and screening by restriction fragment length polymorphism (RFLP). nirS gene fragments were amplified in all analyzed soil samples. Species richness estimated by the number of distinct phylotypes were 83 and 95 in the ambient $CO_2$ treatment and the elevated treatment, respectively. Two phylotypes (type 1 and type 2) were dominant in both of the treatments. Elevated $CO_2$ treatment increased species richness of denitrifying as well as changed a large proportion of denitrifier phylotypes compared to those of the ambient treatment. Overall, the data in this study suggested that the denitrifying communities in the wetland soil are diverse and that the richness of denitrifying bacterial community might be affected by elevated $CO_2$ treatment.

• Korean Chemical Engineering Research
• /
• v.46 no.6
• /
• pp.1095-1099
• /
• 2008

In this study, we investigated that hydrate formation and phase behavior of the $THF+H_2$ binary clathrate hydrates. In order to confirm the binary clathrate hydrate formation we employed the Raman and NMR spectroscopies that are known to be quite powerful tools, particularly for examining the cage occupancy pattern of guest molecules. In addition, we traced the P-T profiles from clathrate hydrate formation and dissociation process, which made it possible for the resulting phase equilibrium boundary to be clearly established. In the binary clathrate hydrate matrix we further identified that the relatively large THF molecules can only occupy the large $5^{12}6^4$ cavities, while the small $H_2$ molecules are entrapped in the empty $5^{12}$ cavities in structure-II, making the hydrate to be stable above 273 K even at relatively low pressure condition. Considering that pure $H_2$ hydrate can be produced at the extreme pressures higher that 1,000 bar, we can conclude that the water-soluble second guest inclusion induces $H_2$ storage and transportation to be readily achievable under much milder conditions.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.20 no.5
• /
• pp.113-120
• /
• 2020

Safety accidents, called industrial accidents in construction work, are causing a lot of casualties, property damage and social controversy in the event of an accident, causing the construction to lose public confidence. The risk of safety accidents at construction sites may continue to increase as the construction of high-rise, large-scale, and multi-purpose complex buildings has increased in recent years. In particular, the most frequently constructed apartment construction among reinforced concrete buildings is designed and constructed with a wall-like structure with no beams for each floor, while the lower floors are made of lamen with columns and beams. As a result, the transfer beam or transfer slab to withstand the upper load is installed on the upper part of the Ramen structure, so the system Dongbari, which is installed as a temporary material during concrete laying construction, may collapse at any time during plowing and curing. The purpose of this study is to apply IT convergence technology to prevent the collapse of the system Dongbari during concrete installation, and to apply many of the variables that may occur during construction on a case-by-case basis to check the stability of the system Dongbari and to propose a model of the anti-conducting prediction system.

• Journal of the Korean Data and Information Science Society
• /
• v.26 no.6
• /
• pp.1353-1366
• /
• 2015

These days Shewhart control chart for evaluating stability of the process is widely used in various field. But it must follow strict assumption of distribution. In real-life problems, this assumption is often violated when many quality characteristics follow non-normal distribution. Moreover, it is more serious in multivariate quality characteristics. To overcome this problem, many researchers have studied the non-parametric control charts. Recently, SVDD (Support Vector Data Description) control chart based on RBF (Radial Basis Function) Kernel, which is called K-chart, determines description of data region on in-control process and is used in various field. But it is important to select kernel parameter or etc. in order to apply the K-chart and they must be predetermined. For this, many researchers use grid search for optimizing parameters. But it has some problems such as selecting search range, calculating cost and time, etc. In this paper, we research the efficiency of selecting parameter regions as data structure vary via simulation study and propose a new method for determining parameters so that it can be easily used and discuss a robust choice of parameters for various data structures. In addition, we apply it on the real example and evaluate its performance.