• Journal of the Korean Magnetics Society
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• v.25 no.3
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• pp.87-91
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• 2015

This paper reports the design of solenoid in a coilgun for high velocity of projectile in a coilgun system, according to diameter of coil. Coilgun using a magnetic force means a mechanism that can control the magnetic material. When momentarily supply a large current to the solenoid instantaneous magnetic field is created around the coil, the projectile is fired by receiving a magnetic force towards the center of the coil, based on the right-hand rule of Fleming. The velocity of projectile is proportional to the magnetic force generated by the electromagnetic coil. The current affects the life of the coil and the current limit exists. Therefore, the coilgun design, which does not exceed the current limit and the magnetic forces are at the maximum, is required. In this paper, whether it is possible fire looking for the optimal number of turns according to the diameter of the coil from AWG #6 to AWG #18 for the design of the solenoid coil, and comparative analysis firing rate associated with it.

• Journal of Environmental Science International
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• v.27 no.1
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• pp.27-38
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• 2018

This study was carried out in the Bukhan River in the summer of 2014 and 2015, to identify the relationship between geosmin and the morphological changes in Anabaena. Identification of Anabaena was conducted using morphological and molecular analyses. Anabaena in this study was similar to Anabaena circinalis, A. crass, and A. spiroides with regard to regular coils, vegetative cell, akinete shape, and size, hoever, it was distinguishabl from A. crass and A. spiroides because of its larger trichome coil size. Additionally, the sequences of phycocyanin (PC) gene from Anabaena showed a 99% genetic similarity with A. circinalis NIES-1647 strain. The coil diameter of trichome ranged from 106 to $899{\mu}m$, and the diameter and abundance showed an insignificant positive correlation (r=0.544, p<0.05). The result of relationship between the coil diameter and the cell number per 360-degree rotation was kept at $33.8{\pm}5.2$ cells per $100{\mu}m$ diameter despite variable diameter. The average geosmin concentrations in 2014 and 2015 were investigated to be 99 ng/L and 35 ng/L, respectively. A. circinalis cell density contributed considerably to the change in geosmin and was positively correlated with geosmin concentration (2014; r=0.599, p<0.01, 2015; r=0.559, p<0.01). Our results suggest that geosmin and coil diameter could be estimated with the help of cell density.

• Journal of Sensor Science and Technology
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• v.7 no.3
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• pp.203-210
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• 1998

An experimental study of an eddy current nondestructive testing system to measure dimensions of cylindrical metallic rods, such as cross-sectional area or diameter, is presented. Impedance characteristics of a solenoid sensor, which are generally based on Maxwell's equations in electromagnetic field, are briefly discussed for inspecting geometrical parameters of the coil sensor and testing materials. A measurement system for detecting the diameter of the metallic rod is implemented. This instrument has capabilities for detecting the sensor output signals and estimating demensions of the testing material, continuously. As a result, it was shown that the eddy current sensor with an encircling coil could estimate the diameter of metallic rod. The implemented measurement system gives accurate information for inspecting the dimension of conducting rod with good sensitivity.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.1
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• pp.61-66
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• 2010

Pay off reel is the device to release in the form of coil. Every time the device becomes a hassle to exchange, each diameter of two forms has been applied to the coil reel. There is the change of reel diameter of the sleeve portion to be the part of segment geometry. This unit is conducting on 3-dimensional modeling design. The basic strength and deformation of the device could be checked in advance by the basis of 3-d modeling data to perform simulations. The production of each part can be completed and assembled. Conducted for the final product which is tested and measured, all items are satisfied within the limits of targets. Due to the development of this device, the efficiency on operations can be increased and the production time becomes shortened.

• Journal of the Korean Magnetics Society
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• v.26 no.2
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• pp.62-66
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• 2016

We designed a model composed a ring type magnet, a yoke, and a sensing coil buried in a projectile for calculating the muzzle velocity based on the voltage induced from sensing coil by simulation. The muzzle velocity was calculated from the master curve obtained through the voltage induced from sensing coil by simulation. The induced voltage increased with increasing the diameter of sensing coil. The projectile's velocity was proportional to the induced voltage when the sensing coil was buried in projectile. The projectile will be surely exploded at the target region by inputting the information of muzzle velocity variation corrected the diameter effect of induced voltage of sensing coil.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.161-164
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• 1996

An actively-shielded $r^{2}$-gradient coil has been developed for brain localized MRI or MRS. Spatial localization is very useful for spatial volume selection in MRI or MR Spectroscopy(MRS). The radial(or $R^{2}-$) gradient coil is useful in reducing the artifact or in improving the SNR by selecting the volume with less number of RF pulses. It is, however, difficult to implement the coil with a gradient intensity strong enough to use it for practical whole-body MRI system. For example, the smallest volume size for selection is just 6 cm in diameter with a 250 Ampere of current driving for a whole-body system (in case of 70-cm-diameter). In this study, an asymetric $r^{2}$-coil with a small diameter of 35 cm has been designed and implemented for brain localized MRI or MRS. An 8-rod high-pass-type birdcage RF coil has also been implemented. The coil set has been developed for 1.0 Tesla Medison MRI system and its performance has been verified experimentally.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.4
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• pp.389-396
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• 2015

A coil design of pulse induction metal detectors has been described. The search coil was demonstrated by using the wire with the diameter of 0.3 mm, 0.5 mm and 1.0 mm and the dielectric plate with the $30cm{\times}30cm$ and $35cm{\times}35cm$, the time constant and the currents of the coil as the variation of the coil size and the number of coil turns was characterized. The coil parameters like the resistance, the inductance and the time constants as the variation of the diameter of the wire, the coil size and the number of coil turns were compared and analysed through the calculation and the measurement. In addition, investigating the coil currents as the variation of the input pulse width, the coil design of pulse induction metal detectors has been discussed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.9
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• pp.640-646
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• 2007

The cooling heat transfer coefficient of $CO_2$ (R-744) for tube and coil diameter (CD), inclined angle of tube and coil pitch of inclined helical coil type copper tubes were investigated experimentally. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and a inclined helical coil type gas cooler (test section). The test section consists of a smooth copper tube of 2.45 and 4.55 mm inner diameter (ID). The refrigerant mass flukes were varied from 200 to 800 [$kg/m^2s$] and the inlet pressures of gas cooler were 7.5 to 10.0 [MPa]. The heat transfer coefficients of $CO_2$ in inclined helical coil tube with 2.45 mm ID are $5{\sim}10.3%$ higher than those of 4.55 mm. The heat transfer coefficients of 41.35 mm CD are $8{\sim}32.4%$ higher than those of 26.75 mm CD. Comparison between $45^{\circ}\;and\;90^{\circ}$ of coil angle, the heat transfer coefficients of $45^{\circ}$ are higher than those of $90^{\circ}$. For coil pitch of gas cooler, the heat transfer coefficients of inclined helical coil gas cooler with coil pitch of 5 mm are similar to those of 10 and 15 mm.

• Journal of Biomedical Engineering Research
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• v.27 no.3
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• pp.94-100
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• 2006

The effectiveness of the treatment of intracranial aneurysms with endovascular coiling depends on coil packing density, the location of aneurysm, its neck dimensions with respect to the aneurysm dome, and its size with respect to the surrounding tissue. Clinical data also suggests that the aneurysm neck size is the main predictor of aneurysm recanalization. In this study, the force impinging on the aneurysm neck in an idealized aneurysm was calculated by using a three dimensional finite volume method for the non-Newtonian incompressible laminar flow. To quantify the effect of neck size on the impingement force, calculations were performed for aneurysm neck diameters (Da) varying from 10% to 100% of the parent artery diameter (Dp). Also, maximum impingement forces were represented by a function of the ratio of the aneurysm neck to the diameter of the parent vessel. The results show that the hemodynamic forces exerted on the coil mass at the aneurysm neck due to the pulsatile blood flow are larger for wide necked aneurysms.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.45-50
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• 2005

Stick type ignition coil(called a Cigar coil) is a kind of transformer for an automobile modulaized of distributer and electric cable. A material of cigar coil is PBT $GF30\%$ resin. This is an excellent engineering plastic with both mechanical and electrical properties. When we insert an HV terminal into the PBT $GF30\%$ resin jacket, it breaks the jacket, because the HV terminal is bigger than the jacket. It is a fatal on durability of a part. In this study, We used ANSYS FEM tool in order to stress analysis by contact. In order to automatically estimate possible maximum diameter of an HV terminal, we used an APDL. In the contact part, we considered the relation of the HV terminal's diameter with the amount of stress that occurred. This relation is able to be applied, in part, to the dimensions of the part design.