• Transactions of the Society of Information Storage Systems
• /
• v.3 no.3
• /
• pp.113-117
• /
• 2007

재생층이 상변화물질로 이루어진 초해상 광디스크에 있어서, 기록 전과 후에 thermal curing 을 실시하여 신호품질과 재생안정성이 크게 향상되었다. Pre-curing으로 수천 회 이하에서 나타나는 short-term stability가 향상되었고, post-curing 한 후 mid-term stability 가 향상되었다. 그리고, pre- and post-curing 후 noise level 은 전반적으로 $1{\sim}2dB$가 낮아졌고, CNR은 $2{\sim}3dB$, jitter 는 $2{\sim}3%$ 가 향상되었다.

• Steel and Composite Structures
• /
• v.15 no.2
• /
• pp.175-202
• /
• 2013

The super convergent laminated composite beam element is newly derived for the lateral stability analysis. For this, a theoretical model of the laminated composite beams is developed based on the first-order shear deformation beam theory. The present laminated beam takes into account the transverse shear and the restrained warping induced shear deformation. The second-order coupling torque resulting from the geometric nonlinearity is rigorously derived. From the principle of minimum total potential energy, the stability equations and force-displacement relationships are derived and the explicit expressions for the displacement parameters are presented by applying the power series expansions of displacement components to simultaneous ordinary differential equations. Finally, the member stiffness matrix is determined using the force-displacement relationships. In order to show accuracy and superiority of the beam element developed by this study, the critical lateral buckling moments for bisymmetric and monosymmetric I-beams are presented and compared with other results available in the literature, the isoparametric beam elements, and shell elements from ABAQUS.

• International Journal of High-Rise Buildings
• /
• v.5 no.4
• /
• pp.263-270
• /
• 2016

In this paper, the stability requirements for diagrid and mega braced structures are examined. The role of the secondary bracing system for the stability of a diagrid structure is discussed. A simple procedure is proposed for the design of the secondary bracing system when it is required. As a case study, the design of the Hearst Tower diagrid and its secondary bracing system are presented.

• Journal of applied mathematics & informatics
• /
• v.14 no.1_2
• /
• pp.415-422
• /
• 2004

In this paper, we investigate the Hyers-Ulam stability and the super-stability of the functional equation f(x＋y＋rxy) = f(x)＋f(y)＋rxf(y)＋ryf(x) which is obtained by combining the additive Cauchy functional equation and the derivation functional equation.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2008.04a
• /
• pp.380-385
• /
• 2008

3 DOFs model for the collision analysis of a bridge super-structure and a super-structure of the navigating vessels were proposed and analyzed. The collision event between the super-structure of vessel and the super-structure of bridge are different from the normal collision event that collided at sub-structure of bridge. Because of its moment arm, the stability force of vessel could affect to the collision behaviors. To consider this effect, 3 DOFs model including two translation DOFs and one rotational DOF were introduced. The restoration forces of the collision system were considered as nonlinear springs. The equations of motion were derived if form of differential equations and numerically solved by 4th order Runge-Kutta method. The accuracy and the feasibility of this model were verified by the numerical example with parameter of moment arm length.

• Korean Journal of Remote Sensing
• /
• v.35 no.5_2
• /
• pp.831-840
• /
• 2019

Recently, the span length of long-span bridges is getting longer. As a result, it has been suggested that a new concept called 'super long-span bridge'. In case of super long span bridges, the structure is being complicated and the importance of structural stability is being emphasized. However, until recently, the most commonly used sensors (dual axis clinometer, anemometer, strain gauge, etc.) have got limit about the bridge monitoring. Consequently, we researched the application of a Global Navigation Satellite System (GNSS) to improve the limit of the existing sensors. In this study, the dual axis clinometer, the anemometer and the strain gauge together with the GNSS were used to analyze the behavior of a super-long suspension bridge. Also, we propose the detailed method of bridge monitoring using the GNSS. This study consisted of three steps. First step calculated the absolute coordinates of the towers and the longitudinal axis direction of the study bridge using the GNSS. In second step, through the analysis of the long-term behavior in shortly after construction, we calculated the permanent displacement and evaluated the stability of main towers. Third step analyzed the behavior of bridge by the wind direction and was numerically indicated. Consequently, the bridge measurement using the GNSS appeared that the acquired data is able to easy processing according to the analysis purpose. If we will use together the existing measurement sensors with the GNSS on the maintenance of the super long-span bridge, we figure each error of measurement data and improve the monitoring system through calibration. As a result, we acquire the accurate displacement of bridge and figure the behavior of bridge. Consequently, we identified that it is able to construct the effective monitoring system.

• Journal of Aerospace System Engineering
• /
• v.14 no.5
• /
• pp.100-106
• /
• 2020

Turbopumps for liquid rocket engines are exposed to various cavitation instabilities under their operating conditions. The instabilities affect the stability of the turbopumps. To make sure of the stability of the turbopump of KSLV-II, the present work examined the characteristics of the cavitation instabilities during the turbopump assembly test. In the test, the LOx pump was operated under super-synchronous rotating cavitation and attached to uneven cavitation. In the vibration analysis of the fuel pump, the characteristic frequency by the super-synchronous cavitation of the LOx pump was clearly shown.

• Textile Coloration and Finishing
• /
• v.32 no.2
• /
• pp.103-110
• /
• 2020

Super engineering plastic(SEP) are applied to high performance and high value industries due to their excellent mechanical properties and high continuous operating temperature. Among them, PES and PEI are amorphous SEPs, and have the advantages of high flexibility, mechanical properties, transparency, and thermal stability. In this study, polyethersulfone(PES) and polyetherimide(PEI) fibers were manufactured to produce flame retardant artificial hair. PES and PEI fibers prepared through a melt-spinning process at a high temperature of 360 to 420℃. They are compared with commercial artificial hair by thermal gravimetric analysis(TGA), linear density, tenacity, and limited oxygen index(LOI) analysis. PES and PEI fibers have similar linear density and tenacity to commercial artificial hair, while their thermal stability and flame retardant are excellent. In particular, flame retardant was analyzed through LOI value and PES was 35.1%, which is superior to commercial artificial hair PET/Br(28.2%) and PET/P(20.2%). Therefore, PES and PEI are suitable as artificial hair for flame retardant.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.239-239
• /
• 2013

For more than four decades, ion-sensitive field-effect transistor (ISFET) sensors that respond to the change of surface potential on a membrane have been intensively investigated in the chemical, environmental, and biological spheres, because of their potential, in particular their compatibility with CMOS manufacturing technology. Here, we demonstrate a new type of ISFET with dual-gate (DG) structure fabricated on ultra-thin body (UTB), which highly boosts sensitivity, as well as enhancing chemical stability. The classic ion-sensitive field-effect transistor (ISFET) has been confronted with chronic problems; the Nernstian response, and detection limit with in the Debye length. The super-coupling effects imposed on the ultra thin film serve to not only maximize sensitivity of the DG ISFET, but also to strongly suppress its leakage currents, leading to a better chemical stability. This geometry will allow the ISFET based biosensor platform to continue enhancement into the next decade.

• International Journal of High-Rise Buildings
• /
• v.3 no.3
• /
• pp.205-214
• /
• 2014

The super high rise building construction is characterized by a large quantity of engineering works and structural components, high demanding of construction technology and complex cross operations. As the height of super high rise building increases, the construction difficulties increase, it is challenging the steel structural building construction technology. In this paper, the key technologies in the construction of Chinese modern super high rise steel structure building have been studied. The innovative tower crane supporting frame suspension disassembly technology has been developed to allow the crane supporting frame to turnover in the air without occupying materials stockyard. A new self-elevating platform technique which is capable of striding over structural barriers has been developed. This new technology allows the platform to be self-elevated along variable cross section column with a maximum 600 mm size change. A new automatic submerged arc welding technology has also been developed to ensure the process continuity and quality stability of welding job on the construction site.