• 보존과학연구
• /
• s.13
• /
• pp.1-8
• /
• 1992

The Wando ship was discovered in 1984 in South Western Korea. The cargo of 30,000 celadons originated from the nearby kiln are thought to date from around the second half of the 11th century. The construction and timber species of the vessel indicate that it was built in Korea. The construcition is distinctive and unusual. There is no keel, rather five hevylongitudinal timbers which are pinned together with mortise and ten on joints. The side planking is attached to the bottom with chine planks. There are 5 strakes of the sides of the ship arranged in a rabbetted construction. All these features are associated with traditional ship construction method of old Korean ship.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2008.09a
• /
• pp.10-15
• /
• 2008

The proper docking block arrangement, loading condition and structural reinforcement are required to ensure structural safety of ship, when she is in re-docking and launching for inspection or repair. The large reaction force due to narrow bottom tangent area, heavy weight and ballast loading are occurred at aft body and fore body of ship. Especially, in case of LNGC, the strength evaluation is necessary for cargo hold areas including mid-body because tank hydro test is performed in dry-dock. The analysis results and experiences to confirm structural safety for docking of conventional LNGC$(138K{\sim}151.7K)$ are introduced in this paper.

• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.2035-2039
• /
• 2008

This paper described an on-line condition monitoring device for rotating machines by measurement of unbalance current due to insulation deterioration. The device consists of a zero-phase current transformer (ZCT), a low-noise amplifying circuit, and a microprocessor unit. The prototype device measures current of $500\;{\mu}A\;{\sim}\;30\;mA$ in frequency ranges from 10 Hz to 3 kHz. An application experiment was carried out on 3-phase induction motors and we could measure current changes caused by a short-circuited turn.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.841-847
• /
• 2009

This paper describes the propagation characteristics of acoustic signals as a function of distance from the location of partial discharge(PD) occurrence to analyze correlation between discharge magnitude and acoustic signal in insulation oil. To measure small acoustic signals produced by PD, we fabricated an amplifier and simulated PD at a needle-plane electrode system set in insulation oil. The amplifier has the gain of 40 dB and the frequency bandwidth of 1.6 kHz$\sim$1.6 MHz. These are enough characteristics for the measurement of acoustic signals. After a comparative calibration experiment by a standard pulse generator and a coupling capacitor, we analyzed the propagation characteristics of acoustic signals in insulation oil.

• Journal of the Society of Naval Architects of Korea
• /
• v.42 no.3
• /
• pp.233-240
• /
• 2005

A model test was carried out, in order to verify the hydrodynamic performances of public 30 feet class sailing yacht. In the initial design stage, the performances and the running attitude of sail yacht including the hull form and sail plan, appendages were estimated by VPP, from which made the representative test conditions. A new experiment system such as captive model device was composed because the running attitude could be changed by wind conditions. The test results show that the minimum resistance is generated in the heeling 20 degree, which was expected in the initial design stage. It is thought to be the useful informations that the keel has au effects on hydrodynamic forces and resistance differences between the upwind and the downwind condition.

• 한국연소학회:학술대회논문집
• /
• 1998.10a
• /
• pp.47-57
• /
• 1998

Characteristics of evaporation, flame propagation at moment of ignition and steady state combustion, and flow characteristics of combustible mixture have been investigated by experiments and computational simulation for the evaporation pot type kerosene burner. The results show how to design the evaporation pot in order to minimize the sticking of residual tar, and also indicate that symmetrical flame propagation along the flame ring from the kernel of ignition is achieved by modication of the shape of ignition part. In the case of steady state combustion, the uniform distribustion of flame at each flame hole is accomplished by proper modification of the piping instruments. The improved design of the structure and parts of the kerosene burner make up enhancement of flame stability and considerable reduction of CO and bad smell emission at moment of ignition.

• Journal of the Society of Naval Architects of Korea
• /
• v.42 no.6 s.144
• /
• pp.637-643
• /
• 2005

A new novel Whipping Factor is proposed as a measure of the ship damage potential due to an underwater explosion bubble pulse. The factor was derived from the relationships among the charge weight, its depth and the fluid acceleration due to pulsating gas bubble. From the whipping response analyses for three uniform Timoshenko beams with similar characteristics of real naval surface ships, we have confirmed the maximum bending moment responses of beams due to whipping are almost same if the applied whipping factor is constant regardless of the charge weights and depths, which could validate the proposed whipping factor.

• Journal of Acupuncture Research
• /
• v.18 no.5
• /
• pp.179-184
• /
• 2001

The Tolosa-Hunt syndrome(THS) consists of a painful ophthalmoplegia related to a granulomatous inflammatory process in the cavernous sinus, which may be documented by cerebral magnetic resonance imaging with gadolinium enhancement. Generally, it has been reported that 2 weeks steroid therapy relieves the symptoms(periorbital pain, ophthalmoplegia) of THS. In this case, there had been no improvement of symptoms by western medical treatments(steroid & analgesics). but, the symptoms were resolved clearly by acupuncture therapy during 6 weeks(5 times/week). If more clinical trials like this are proved to be effective in THS, we can expect that acupuncture will be another therapeutical modality in THS.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.24 no.4
• /
• pp.1-8
• /
• 1987

In this paper negative drift forces are discussed, which act on a two-dimensional cylinder exposed to slightly modulated waves in water of finite depth. By combining matched asymptotic expansion method with multiple scale technique, it is clearly shown that the slowly-varying drift force can be negative under certain circumstances: i) Incident waves are irregular or slightly modulated. ii) The water depth is finite compared to the wave length of carrier waves. iii) The gap between the keel of the cylinder and ocean floor is narrow. Then the negative drift forces are caused by the unbalance of hydrostatic force associated with set down. Real fluid and wave breaking effects are not considered.

• The Journal of the Korean dental association
• /
• v.51 no.10
• /
• pp.551-555
• /
• 2013

The purpose of this study was to give a guideline for selecting the nickel-titanium (NiTi) file by review from many studies. Since the early 1990s, several instrument systems manufactured from NiTi have been introduced into endodontic practice. The specific design characteristics vary, such as tip shape and size, cross sectional view, helix angle, and pitch space. Some of the early systems have been removed from the market or play only minor roles; others are still widely used. New designs continually are produced, but the extent to which clinical outcomes will depend on design characteristics is difficult to forecast. In this study, I have reviewed the different design characteristics in respect of the safety and efficiency. With the review from many studies, I concluded that the clinicians must be understand the specific design characteristics for selecting the ideal NiTi rotary instruments.