• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.25-27
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.769-770
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• 2010

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.271-277
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• 2013

Skin pass rolling is a very important process for applying a certain elongation to a strip in the cold rolling and annealing processes, which play an important role in preventing the stretching of the yield point when the material is processed. The exact prediction of the rolling force is essential for obtaining a given elongation with the steel grade and strip size. Unlike hot rolling and cold rolling, skin pass rolling is used to apply an elongation of within 2% to the strip. Under a small reduction, it is difficult to predict the rolling force because the elastic deformation behavior of the rolls is complicated and a model for predicting the rolling force has not yet been established. Nevertheless, the exact prediction of the rolling force in skin pass rolling has gained increasing importance in recent times with the rapid development of high-strength steels for use in automobiles. In this study, the possibility of predicting the rolling force in skin pass rolling for producing various steel grades was examined using foil rolling theory, which is known to have similar elastic deformation behavior of rolls in the roll bite. It was found that a noncircular arc model is more accurate than a circular model in predicting the roll force of high-strength steel below TS 980 MPa in skin pass rolling.

• The Korean Journal of Petroleum Geology
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• v.4 no.1_2 s.5
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• pp.1-11
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• 1996

Multichannel deep seismic reflection data in the Main Pass area of the northern Gulf of Mexico are interpreted in this study for the stratigraphy and the depositional history. Structural analysis of deep seismic reflection data provides new information on the locations of paleo-shelf margins and the basement. The basement occurs at about $7.5{\cal}km$ depth at the northern end of seismic line LSU-1 in the Mississippi shelf. The Jurassic and early Cretaceous shelf margins occupy approximately the same position, whereas the Oligocene shelf margin occurs about 28 km farther landward. Ten major seismic stratigraphic sequences are identified for the Mesozoic and Cenozoic sed-imentary section. Correlation of sequence boundaries defined in this study with those in other areas of the circum-Gulf region indicates that majo. regional unconformities formed at the mid-Miocene (10.5 Ma), mid-Oligocene (30 Ma), mid-Cretaceous (97 Ma), and top-Jurassic (131 Ma). Three distinct periods a.e recognized in the depositional history of the Main Pass area of the northern Gulf of Mexico: (1) shallow ma.me deposition du.ins the period from the opening of the Gulf to the mid-Cretaceous, (2) deep marine deposition in the Cretaceous to the mid-Oligocene, and (3) shallow marine deposition prevailed since the mid-Oligocene to present. A comparison of depositional rates between the Main Pass area and the Destin Dome area indicates that the northern Gulf of Mexico continental margin was initiated as a terrigenous sediment wedge province in the late Cretaceous.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6702-6709
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• 2014

In this study, a susceptibility weighted image (SWI) showed a wrapped phase and a non-uniformity of the rapid susceptibility difference. Consequently, the bandwidth limits at low frequency were improved by applying HPF. From November 2013 to March 2014, a three-dimensional SWI was obtained from patients and compared with the existing images and HPF phase images. The maximum and minimum signal intensity differences and non-uniformity were analyzed. As a result, a high pass filter before and after applying the maximum and minimum of the signal intensity difference was decreased by 274.16% (498.98), and the non-uniformity was decreased by 439.55% (19.83). After applying the HPF, a comparison with the existing phase images revealed the HPF phase images to have high signal and image uniformity of the SWI image. A high pass filter method can effectively remove the non-uniformity and improve the overall image quality.

• Korean Journal of Optics and Photonics
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• v.19 no.3
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• pp.229-236
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• 2008

The optimum conditions of second harmonic generation (SHG) can be successfully achieved experimentally using single pass and double pass methods of a pumping beam. The beam has a power of several Watts radiated by a DOFA (Diode Laser Oscillator & Fiber Amplifier) system, which is a high power CW wavelength tunable infrared laser system, in a PPLN (Periodically Poled MgO doped Lithium Niobate) nonlinear crystal. In the case of a single pass method, the parameters are the wavelength of 535 nm for SHG and the output power of 245 mW generated from the pumping input beam with wavelength of 1070 nm and the power of 2.45 W at phase matching temperature of $108.9^{\circ}C$. The conversion efficiency of SHG was 10%. In order to enhance the output of SHG, the double pass method of the SHG system of a PPLN using a concave mirror for the retroreflection and a pair of wedged flat windows for phase compensation was also presented. In this double pass system, we obtained the SHG output beam with the wavelength of 535 nm and the maximum power of 383 mW at optimum phase matching temperature of $108.5^{\circ}C$ by using an incident pumping beam with wavelength of 1070 nm and the power of 2.45 W. The maximum conversion efficiency is 15.6%, which is more than that of the single pass method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.8
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• pp.819-826
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• 2002

In this paper, the performance of Au / $Ba_{0.5}Sr_{0.5}TiO_3$ (BST) / Magnesium oxide (MgO) two-layered electrically tunable band-pass Filters (BPFs) is demonstrated. The devices consist of microstrip, coplanar waveguide (CPW), and conductor-backed coplanar waveguide (CBCPW) structures. These BST thin film band-pass filters have been designed by the 2.5 D field simulator, IE3D, Zeland Inc., and fabricated by thin film process. The simulation results, using the 2-pole microstrip, CPW, and CBCPW band-pass filters, show the center frequencies of 5.89 GHz, 5.88 GHz, and 5.69 GHz, and the corresponding insertion losses are 2.67 dB, 1.14 dB, and 1.60 dB, with 3 %, 9 %, and 7 % bandwidth, respectively. The measurement results show the center frequencies of 6.4 GHz, 6.14 GHz, and 6.04 GHz, and their corresponding insertion losses are 6 dB, 4.41 dB, and 5.41 dB, respectively, without any bias voltage. With the bias voltage of 40 V, the center frequencies for the band-pass filters are measured to be 6.61 GHz, 6.31 GHz, and 6.21 GHz, and their insertion losses are observed to be 7.33 dB, 5.83 dB, and 6.83 dB, respectively. From the experiment, the tuning range for the band-pass filters are determined as about 3 % ~ 8 %.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.4
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• pp.307-312
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• 2017

Laser cladding has some advantages compared to conventional cladding technologies such as arc welding and thermal spraying. Laser cladding produces a metallurgically well-bonded clad layer with a lower dilution ratio and few defects. Based on the characteristics of a 1-pass clad layer with many parameters, which were investigated in a previous report, it was found that it was essential to overlap a 1-pass clad layer when cladding a large area. In this study, the shape differences of multi-pass clad layers with various overlapping ratios were compared. Then, the alloying element distribution of cladding with a certain overlapping ratio was investigated using EDS and EPMA. As the overlapping ratio increased, the length of the clad decreased and its height increased. In addition, the height of the multi-pass cladding was higher than that of the 1-pass cladding under the same condition. The Fe content of the highly diluted first clad was found to be approximately 20 % in an element analysis. However in the area outside of the first clad, the Fe content was decreased to 10 % as a result of minimum dilution, and a uniform distribution of elements was found.

• The Journal of the Acoustical Society of Korea
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• v.23 no.4
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• pp.309-315
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• 2004

To estimate the rate of noise contribution caused in each part of a vehicle in the course of a pass-by noise test. researches precedent have been made to study characteristics of nearby radiation noise measured on both sides of cars in a stationary state. With different revolutions per minute of engine. 2.800rpm and 3.200rpm respectively, in the measurement area of pass-by noise, the experiments have been conducted 7.5 meters away from the central axis of the test vehicle to study direction radiation according to frequencies. The results can be applied to reduce vehicle noise.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.163-166
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• 2005

Multilayer LTCC technology enables RF modules to be reduced dramatically by taking advantage of the three dimension flexibility. Compared to a conventional two dimensional PCB, LTCC allows higher density, reduced size, and lower cost. In this research, BPF based on LTCC for 900MHz ZigBee application was implemented which can replace SAW filter with using the material of the Dupont9599's dielectric constant 7.8. And distributed baud pass filter for 900MHz ZigBee system applications is presented. Using resonator stripline and capacitance, 2nd order band pass filter was designed. Adjusting resonator's length and capacitance is easy to tune at accurate center frequency by shifting band because ZigBee system is using narrow bandwidth, $902MHz^{\sim}928MHz$. Also resonator has no limitation in space, so reducing size is possibile. Designed filter had I.L. 2.8dB at 915MHz and attenuation at 815MHz, 1015MHz was 16dB, 15dB, respectively. Therefore, the sharpe cut-off and good insertion loss for ZigBee system application.