• Journal of Welding and Joining
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• v.18 no.6
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• pp.74-82
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• 2000

The fluxless wetting properties of UBM-coated Si-wafer to the binary lead-free solders(Sn-Ag, Sn-Sb, Sjn-In, Sn0Bi) were estimated by wetting balance method. With the new wettability indices from the wetting curves of one side coated specimen, the wetting property estimation of UBM-coated Si-wafer was possible. For UBM of Si-chip, Au/Cu/Cr UBm was better than au/Ni/TI in the point of wetting time/ At general reflow process temperature, the wettability of high melting point solders(Sn-Sb, Sn-Ag) was better than that of low melting point one(Sn-Bi, Sn-In). The contact angle of the one side coated Si-plate to the solder could be calculated from the force balance equation by measuring the static state force and the tilt angle.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.4
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• pp.363-368
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• 2005

This paper proposes an LOS(line-of-sight) guidance system of a ship for path following. From the viewpoint of a control configuration, guidance is a special type of compensation algorithm that is placed in front of the controller to accomplish navigational objects. A guidance system generates a reference trajectory for trajectory tracking or path control and decides the desired velocity, position and heading angle. A control system executes commands based on a reliable guidance law during navigation. An LOS vector from the vessel to a point on the path between two way-points in straight-line navigation or a point among turning circle in turning navigation is selected, and then a heading angle is calculated to converge the desired path based on the LOS vector. The LOS guidance law is defined for the straight-line and the turning circle, respectively. The effectiveness of the suggested LOS guidance system is assured through computer simulation.

• Textile Coloration and Finishing
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• v.15 no.3
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• pp.185-191
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• 2003

Surface modification of poly(ethylene terephthalate) (PEI) films by treatment with ethoxylated alkylaminoanthraquinoes which was synthesized by the reaction of 1-aminoanthraquinone with poly(ethylene glycol) via a series of methylene spacer were investigated. The synthesized ethoxylated alkylaminoanthraquinones showed definite cloud point as in nonionic surfactants, and the adsorption of the compounds on PET increased near the cloud point. At same temperature the adsorption increased with the length of methylene spacer; hexyl-octyl-, and decyl-. The adsorption was limited to the extreme surface of PET film, which made the surface of PET film hydrophillic by reducing water contact angle.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.4
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• pp.429-435
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• 1998

Experiments were conducted to investigate the turbulent flow characteristics from on oblique impingement surface to an plane jet at the jet Reynolds number(Re based on the nozzle width) $3{\times}10^4$ The jet mean velocity and turbulent intensity profiles have been measured along the impingement surface by hot-wire anemometer. The nozzle-to-plate distance(H/B) ranged from 2 to 10 and the oblique angle (a) from 45 to 90 degree. Also the secondary peak of the turbulent intensity was observed at H/B=4 S/B 5 and a=90 degree. It has been found that the stagnation point shifted toward the minor flow region as the oblique angle decreased and the position of the stagnation point nearly coincided with that of the maximum turbulent intensity.

• Journal of the Korean Society for Precision Engineering
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• v.4 no.2
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• pp.47-55
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• 1987

Recently, in precision working, precision is in submicron. Therefore, when we measure various finished goods in superfine measurement, because it is relatively difficult to disregard effect of surroundings, these effect of surroundings must be compensated or canceled. In this study, for roundness measurement, three point method is researched which is able to cancel the effect of rotation accuracy of axis and eccenricity of workpiece. It is difference between this three point method and tradi- tional three point method whose measuring apparatus have three movable pickups posit- ioned with angle and between the pickups. As a results, when rotation accuracy of axis is varied from $0.02\mu\textrm{m}$ to $0.05\mu\textrm{m}$ the width of variation of measured roundness is $0.04\mu\textrm{m}$. And, when eccentricity of workpiece is varied from 0 to $4\mu\textrm{m}$, the width of variation of measured roundness is $0.005\mu\textrm{m}$. These error width are disregardable because they are in 10% of measured roundness. Therefore, by this three point method, the effect of rotation accuracy of axis and the effect of eccentricity of workpiece are canceled. And we are able to select the angle between the pickups ($\phi$ and $\tau$) by means of relation between $F_{k}$ and K.

• Journal of the Korean Home Economics Association
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• v.39 no.10
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• pp.97-109
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• 2001

It is thought that a composition of trousers is related to fabrics with single breadth. Therefore, trousers are designed with pattern using this fabrics with single breadth. However, in the old pattern of trousers, the breadth of 33cm-35cm was not considered in designing patterns. In this context, deciding which pattern design is better is not easy as there are a variety of estimation methods. So in this study, standardization of drafting is pursued by an objective pattern design. For this, a base angle of the trouser closely relating to a form and function was measured and using the height and the base angle, a trouser pattern design was tried. For a measurement of the base angle, 5 subject were selected. They are 25-29 year-old male graduates with fine physical standard. The base angle was measured with symphysis pubis point as a standard when subjects sat with their legs crossed, when they stood with their legs open (not forced artificially) and when they laid down with their legs open. The distance between a knee inside joint and knees was measured three times and the resultant value was used for the pattern design. For a design of trousers, the height was applied and the base angle was fixed. As a pattern drawing, using the height, a base angle and circumference of the hip, a trouser was designed. The production method for the pattern design is as follow: (1) The length formula, is height + $\frac{height}{2}$ (2) The hip girth formula is $\frac{hipgirth}{2}$ - $\frac{hipgirth}{20}$(3) A crotch angle is fixed at $72^{\circ}$. (4) The ratio of outer leg length to leg width is 5 : 8. (5) The component ratio of the upper outer leg length to the pant length is 5 : 8. (6) The ratio of the division point of front right inner leg length and left inner width to upper outer leg length is 5 : 8.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.230-233
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• 2003

Simulation model of induction type fixed speed wind power generator is developed. It is shown that the peak value of inrush current during start up changes according to the firing angle control strategy of soft starter. New proposed firing angle control scheme showed $25\%$ of reduction of peak current which results in smaller drop of gird voltage at the point of common coupling during start up.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.37-40
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• 2009

This study was performed to design of $H_2O_2$/Kerosene catalyst ignition injector and cold flow test to measure the mass flow rate and spray angle. Mass flow rate and spray angle were measured by designed injector through cold flow test. Result of test kerosene mass flow rate was measured 12.88 g/s and 40 deg of spray angle at pressure drop 3 bar as same as design point. And hydrogen peroxide was measured 94.39 g/s at pressure drop 1 bar smaller than design point.

• Steel and Composite Structures
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• v.21 no.3
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• pp.573-588
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• 2016

Carbon Fiber Reinforced Plastic (CFRP) and Titanium Alloy (Ti6Al4V) stack, extensively used in aerospace structural components are assembled by fasteners and the holes are made using drilling process. Drilling of stack in one shot is a complicated process due to dissimilarity in the material properties. It is vital to have optimal machining condition and tool geometry for better hole quality and tool life. In this study the tool wear and hole quality were analysed by experimental analysis using three modified twist drills and online tool condition monitoring using Acoustics Emission (AE) sensor. Helix angle and point angle influence tool performance and cutting force. It was found that a tool geometry (TG1) with high helix angle of $35^{\circ}$ with low point angle $130^{\circ}$ results in reduction in thrust force of 150-500 N range but the TG2 also perform almost similar to TG1, but when compared with the AErms voltage generated during drilling it was found that progressive rise in voltage in TG1 is less with respect to TG2 which can be attributed to tool life. In process wear monitoring was done using crest factor as monitoring index. AErms voltage were measured and correlated with the performance of the drills.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.69-77
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• 1996

To design high-effective profile in screw rotor profile using in screw compressor, we design the symmetric type changing the number of lobes and the non-symmetric type changing the neighbourhood of the top point of lobe. Then, we calculated the performance value of profile according to the scale of these non-symmetric's wrap angle. We had the results as follows. 1. About the non-symmetric case, the larger a wrap angle is the shorter seal line is and the smaller blow hole is, thus we know what the large wrap angle profile is better than the small one. 2. We know what the non-symmetric profile is better than the symmetric profile in the result of the compare of seal line's length, blow hole's area, volume curve. 3. About the non-symmetric case, the deformation of the neighbourhood of lobe's top point of the rotor profile has a large effect upon the increase of performance because the length of seal line became short and the area of blow hole is small.