• Advanced Composite Materials
• /
• 제16권3호
• /
• pp.207-221
• /
• 2007

The filling process of resin injection/compression molding (I/CM) can be divided into injection and compression phases. During the resin injection the mold is kept only partially closed and thus a gap is present between the reinforcements and the upper mold. The gap results in preferential flow path. After the gap is filled with the resin, the compression action initiates and forces the resin to penetrate into the fiber preform. In the present study, the resin flow in the gap is simplified by using the Stokes approximation, while Darcy's law is used to calculate the flow field in the fiber mats. Results show that most of the injected resins enter into the gap during the injection phase. The resin injection time is extremely short so the duration of the filling process is determined by the final closing action of the mold cavity. Compared with resin transfer molding (RTM), I/CM process can reduce the mold filling time or injection pressure significantly.

• 대한후두음성언어의학회지
• /
• 제16권1호
• /
• pp.5-9
• /
• 2005

Background and Objectives : Glottal area waveform(GAW) shows the plot of glottal area versus time through the 1 cycle. This study is designed to see how it can be applied to laryngeal patients. Material and Methods : A GAW analysis was peformed on 11 patients before and after surgery and 22 persons without laryngeal problems were recruited for control. Acoustic and aerodynamic analysis with VHI(voice handicap index) evaluation were performed. Results. Significant changes in baseline offset, gross closing rate and VHI were observed postoperatively. Other parameters were changed but insignificant. Conclusion : GAW maybe used to evaluate patient with voice problems.

• 펄프종이기술
• /
• 제40권2호
• /
• pp.1-7
• /
• 2008

The trend of using more hardwood and recycled fibers, and closing more tightly of the paper mill white water system has resulted in build-up of fines as well as organic and inorganic contaminants in the white water. This changes in papermaking wet end requires developing chemical additive system that provides good fiber retention and drainage in closed white water system. In this study the effect of charge densities and chemical characteristics of microparticle systems consisted of cationic guar gums and anionic colloidal silica sols on drainage and retention have been examined. Results showed that higher charge density of cationic guar gum and anionic colloidal silica sol gave better retention and drainage. Particularly highly structured silica gave greater retention efficiency.

• Journal of Welding and Joining
• /
• 제31권4호
• /
• pp.23-27
• /
• 2013

Laser heat source was used for automotive interior and exterior parts to reduce weights. Typically, 900's nm wavelength of laser has been widely used for polymer joining, however, the transmittance of the laser beam thorough clear polymers such as PMMA or PC has been an issue to overcome. To solve this issue, 1,940nm laser was applied on the clear polymer for the better absorption and 900nm laser beam was used for main laser for the joining. Conventional Gaussian or Elliptical heat source approximation has limitation in polymer which had deeper skin depth where major laser beam absorbs. To accurately simulate the physical laser beam absorption and joining optical properties were experimentally measured for the computer FEM simulation. The simulation results showed close correlation between theoretical and experimental results. The developed laser process is expected to increase productivity and gap closing which can cause failure of joining in laser material processing.

• Bulletin of the Korean Chemical Society
• /
• 제32권3호
• /
• pp.909-914
• /
• 2011

An improved convergent and economical method has been developed for the synthesis of erlotinib, a 4-anilinoquinazoline and an EGFR-tyrosine kinase inhibitor for treatment of non-small-cell lung cancer. The final two steps for the formation of this 4-anilinoquinazoline from suitable 2-aminobenzonitrile intermediate and 3-ethynylaniline were modified and were performed in a simple one-pot reaction. The ring-closing mechanism for the formation of erlotinib from the suitable formamidine intermediate and 3-ethynylaniline was investigated and determined to proceed via the formation of phenyl benzamidine intermediate rather than involving Dimroth rearrangement reported earlier. The new benzamidine intermediate was isolated for the first time and characterized.

• 한국안전학회지
• /
• 제25권6호
• /
• pp.123-127
• /
• 2010

A fire disaster is very serious in the closing space like subway station. In this study, the simulation on fire diffusion is performed to get the temperature history curve, which is used for the fire resisting structural analysis. Most of subway stations are built by the reinforced concrete structure, but recently steel structures are selected for the larger space or beauty. Steel structures relatively have more weaknesses against fire, so it is necessary to develop the method for evaluating fire-resisting capacity in this kind of structures. The developed method is applied to the subway station in Daegu city. It shows that the developed method can be used to simulate the fire disaster and to get the temperature history curve and evaluate the safety of steel structures against the fire.

• 한국공간구조학회논문집
• /
• 제17권2호
• /
• pp.79-87
• /
• 2017

The retractable roof structure is used in various fields and it is classified for steel retractable system and soft retractable system. For the domestic industry, it is in the initial phase now and the demand of the retractable roof structure is expected to increase in the future. Therefore, this paper is classified for steel retractable system and soft retractable system from the retractable roof structures in overseas to survey and analyze the cases of wind velocity on retractable roof structure in Japan that uses the same wind velocity criteria like Korea regarding the open-close time and average open-close time for retractable roof area.

• International Journal of Fluid Machinery and Systems
• /
• 제6권4호
• /
• pp.213-221
• /
• 2013

The characteristics of the thrust for ship propulsion equipment directly driven by air compressed by pressure fluctuation in a blower piping system are investigated. The exhaust valve is positioned upon the air ejection hole in the discharge pipe in order to induce the large-scale pressure fluctuation, and the effects of the valve on the pressure in the pipes and the thrust for the propulsive nozzle are examined. The pressure in the pipes decreases immediately after the valve is opened, and it increases just before the valve is closed. The thrust for the propulsive nozzle monotonically increases with increasing number of revolutions and depth. The interfacial wave in the nozzle appears in the frequency of approximately 4Hz, and it is important for the increase of the thrust to synchronize the opening-closing cycle for the exhaust valve with the generation frequency of the interfacial wave. The finite difference lattice Boltzmann method is helpful to investigate the characteristics of the flow in the nozzle.

• 비파괴검사학회지
• /
• 제21권1호
• /
• pp.22-31
• /
• 2001

Some techniques developed recently for sizing smalt fatigue cracks are described. One is an ultrasonic technique which deals with a small closed crack, where both the stress closing the crack and the crack size are determined by analyzing inverse problem. Here, difficulties encountered in NDE of closed cracks by usual ultrasonic techniques are summarized in advance. Secondly, the closely coupled probes potential drop (CCPPD) technique, which is based on d-c potential drop measurement, is explained fur sizing small cracks. The CCPPD technique is not affected by crack closure. Finally, a discussion is given on NDE of materials degradation in conjunction with sensitive NDE of small cracks.

• 대한후두음성언어의학회지
• /
• 제18권1호
• /
• pp.16-21
• /
• 2007

Many kinds of materials have been used up to now for vocal fold paralysis. Although silastic block has been the most popular material, some difficulties in carving, positioning, and placing have been the causes to find more easily applicable materials. Hy-droxylapatite, gelfoam, hyaluronic acid and fat have been suggested and used for this purposes with some limitations. During last decade, Gore-Tex was introduced and replacing old materials and showed good surgical results with less difficulties. This material is biocompatible and familiar to surgeons because it had been invented in 1960's. In addition it is easy to shape and place Gore-Tex into the window with many clinical experiences. In some problem cases, it is easy to remove from the body with less damage to surrounding tissue. The basic surgical techniques are as follows. 1) Creating window. 2) Positioning and placing the material. 3) Immobilizing the material and closing the window. The modified methods ae introduced in details with figures.