• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.2
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• pp.121-127
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• 2017

From the perspective of commercializing rotating machines equipped with magnetic bearings, maintaining the error between the mechanical center and the magnetic center within an acceptable level is crucial. The existing method of measuring the center error is to adjust the position references that minimize the current imbalance present in levitation control outputs. However, this method can be applied only after all the components of the system are operational. In this paper, we present a new method of estimating the center error by using only the position sensors and a current source. A force model that relates the position of the rotor with the coil currents is set up. Using this model, the center error is estimated by minimizing the difference between the force angles and the contact angles measured in a pull test. The feasibility of the method is numerically and experimentally validated.

• Archives of Plastic Surgery
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• v.34 no.2
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• pp.237-242
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• 2007

Purpose: Gynecomastia is an abnormal increase in the volume of the male breast. Patients affected by gynecomastia with significant glandular enlargement may respond to suction alone and/or sharp dissection and excision. The purpose of this report is to introduce the indications and results of authors' two techniques. Methods: The diameter of parenchyme was determined by a pinch test after liposuction. For the parenchymal diameter less than 4 cm, ultrasound-assisted liposuction was performed, in conjunction with the "pull-out technique" to effectively remove the fibrofatty tissue of the male breast through a single 5-7 mm incision. For the parenchymal diameter more than 4 cm, ultrasound-assisted liposuction and excision were applied through 2.5 cm periareolar approach. Results: A total of 94 patients (185 breasts) underwent the operation from October 2000 to October 2003 and mean follow-up period was 12 months. The volume of aspirates ranged from 50 to 450 cc per breast. There were no major complications such as skin flap necrosis. Five reoperations were performed for 1 hypertrophic scar, 2 under-resected and 2 hematoma cases. The patient's satisfaction was high and most of them were pleased with the shape of the breasts and scars. Conclusion: These procedures can minimize scars and reduce the incidence of contour problem such as saucer deformity, and provides consistent results. Patients can return to full activities in 48 hours. It can be offered as an option for the treatment of gynecomastia.

• Journal of the Korean Arthroscopy Society
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• v.10 no.1
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• pp.26-32
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• 2006

Purpose: We evaluated the result of the degree of reduction and anterior instability after arthroscopic treatment of tibial spine fractures. Materials and Methods: Thirty-two cases of tibial spine fractures treated with arthroscopic procedure could be evaluated and the mean follow-up period was $18\;(12{\sim}48)$ months. Evaluations included Lachman test, rotatory instability examination and side to side difference (SSD) using KT-2000 arthrometer. The degree of radiologic reduction was classified as accurate reduction, anterior elevation and reduction failure, according to which the degree of anterior instability was measured. Results: There were twenty three cases (71%) of accurate duction, eight cases (25%) of anterior elevation and one case (4%) of education failure. Eight (29%) of twenty eight cases with pull-out method showed anterior elevation. The SSDs of the accurate reduction and the anterior elevation group were 2.0 mm and 2.8 mm, respectively showing no significant difference. However, the percent age of grade 0 Lachman test and SSD less than 3 mm of the accurate reduction group were significantly higher. Conclusion: Accurate reduction is important in reducing anterior instability especially in unstable fractures. Therefore, arthroscopic pull-out method should be performed with great caution to avoid anterior elevation of the fracture fragment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.661-667
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• 2016

This study evaluated the potential of methodology development of the helical type anchor for soft ground applications. The rotational penetration of the helix structure might make construction-steps easy without the soil spitting and reusable rods could reduce the material cost. Removal of the anchors would be simple as a construction, which can be named the removal anchor. The anchoring resistance after construction is strongly related to the number of helixes resulting in a concise design process. The investigation involved a chamber test with soft soils. In the test, a specially designed and fabricated helical anchor and torque-driver were used to obtain the maximum pull-out resistance of the anchor after rotational penetration. As a result of the tests, The rotational torque and pull-out resistance have a proportional relationship with the strength of the prepared soils. Within the range of the study, the torque of the anchor penetrating increased with increasing pull-out resistance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.11
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• pp.3433-3440
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• 1996

This paper was investigation of the stres corrosion cracking(SCC) mechanism and the properties of corrosion fracture surface of glass fiber reinforced plastics(GFRP) produced by hand lay up(HLU) method in synthetic sea water. Test material is GFRP, that was used vinylester type epoxy acrylate resin and an unsaturated polyester as the matrix and the chopped strand mat(CSM) type E-glss fiber as the reinforcement. The slow strain rate test(SSRT) was performed on dry, wet and saturated wet specimens in sea water. Here the pH concentration of synthetic sea water was 8.2 and the strain rate is 1 x $10^{-6}$($sec^{-1}$) and test temperature ranges varied from $-60^{\circ}C$ to $80^{\circ}C$. It could be confirmed the fact that wet specimens tested at a particular test temperature ranges were appeared the eviences of SCC such as con-planar, mirror and hackle zone. Moreover, SCC of GFRP in sea water was characterised by falt fracture surfaces with only small amounts of fiber pull-out, in partial.

• Journal of the Korean Geotechnical Society
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• v.38 no.4
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• pp.21-32
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• 2022

Steel pile foundations are widely used for offshore constructions due to their high bearing capacity and efficiency. Typically, offshore structures that have reached the end of their design life are required to be demolished. However, pile foundations are often left on site due to technical and economic limitations. The pile left on the site not only pollutes the environment, but can also cause obstacles for the construction of new structures. Therefore, research is required to completely eliminate these foundations at the site. In this study, a new type of double-wall pile foundation that can drastically reduce the pull-out load was conceptually proposed, and a series of model tests were performed to validate the performance of the double-wall pile foundation. The installation and extraction of the double-wall pile were simulated in dry sand in the model test, and the measured up-lift load was compared to that of the conventional pile. According to the result, the maximum up-lift load induced by the decommissioning of the double-wall pile was reduced by 45% when compared to the traditional pile in dense sand. This study verified the mechanism for reducing the up-lift load of the double-wall foundation and confirmed the possibility of completely decommissioning a pile that has reached the end of its nominal service life.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1858-1864
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• 2009

In this paper, we design a non-volatile memory IP, 1-kb one-time programmable (OTP) memory, used for power management ICs. Since a conventional OTP cell uses an isolated NMOS transistor as an antifuse, there is an advantage of it big cell size with the BCD process. We use, therefore, a PMOS transistor as an antifuse in lieu of the isolated NMOS transistor and minimize the cell size by optimizing the size of a OTP cell transistor. And we add an ESD protection circuit to the OTP core circuit to prevent an arbitrary cell from being programmed by a high voltage between the terminals of the PMOS antifuse when the ESD test is done. Furthermore, we propose a method of turning on a PMOS pull-up transistor of high impedance to eliminate a gate coupling noise in reading a non-programmed cell. The layout size of the designed 1-kb PMOS-type antifuse OTP IP with Dongbu's $0.18{\mu}m$ BCD is $129.93{\times}452.26{\mu}m^2$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.405-413
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• 2013

In this paper, a high-reliability differential paired 24-bit eFuse OTP memory with program-verify-read mode for PMICs is designed. In the proposed program-verify-read mode, the eFuse OTP memory can do a sensing margin test with a variable pull-up load in consideration of programmed eFuse resistance variation and can output a comparison result through a PFb (pass fail bar) pin by comparing a programmed datum with its read one. It is verified by simulation results that the sensing resistance is lower with $4k{\Omega}$ in case of the designed differential paired eFuse OTP memory than $50k{\Omega}$ in case of its dual-port eFuse OTP memory.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.525-534
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• 2007

The peculiarity of end-expanded soil nailing method(EESNM) is in fixing the wedge-type steel body spreaded by collars and grouting its surroundings by cement milk within soils, after extending hole bottom over drilling hole diameter with top drill bit. The present study was done to establish the effect of this method. Laboratory model test were carried out to investigate the behavior characteristics with the performance of the pull-out test and failure experiment, after preparing soil test box having 1,300mm length, width 1,000mm, and height 1,100mm, and the same experimental condition was set up to compare with the general soil nailing method(GSNM). The pull-out force of about 23 percentage was increased, and the horizontal displacements 1.2 from 9.1 percentage in soil-nailed wall decreased in EESNM compare with GSNM. The axial force acting on nail increased considerably at load level over 7 ton in EESNM and 5 ton in GSNM. The predicted failure line from the maxima analyzed by axial tensile strain located at long distance from soil-nailed wall in EESNM. The EESNM demonstrated the superiority of reinforcement effect in comparison with GSNM from the results above mentioned.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.62-69
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• 2010

Many electric poles in the softground have been collapsed due to external load. In this study, 10 types of tests were performed with variation of location, numbers and depths of anchor blocks as well as depth of poles to find horizontal earth pressure through full scale pull-out tests. The horizontal earth pressure increased with embedded depth of electric pole, and earth pressure of lower passive zone decreased. The deeper of anchor block, earth pressure of passive zone becomes less. 4 anchor blocks decreased earth pressure at G.L.-0.9[m]. It is considered that 4 anchor blocks installed along 80[cm] vertically are main reason. Overall, when more anchor blocks are constructed, excavation area is large, and constructivity such as backfill is bad, therefore one anchor block would be preferred.