• Proceedings of the KWS Conference
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• 2005.11a
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• pp.231-233
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• 2005

Laser have been utilized as a heat source for the soldering of electronic components for the their capability of localized heating and faster heating rate. Laser soldering process, especially the diode laser soldering of BGA solderball was investigated. In this study, an attempt was made to investigate the possibility of laser soldering using Sn-37Pb and Sn-3Ag-0.5Cu solderball. The laser energy absorbed on the pad raised the temperature of the solderball forming a reflowed solder bump. The result were discussed based on the measurement of pull and shear strength of the bond.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.53-54
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• 2000

Measurements of the direct current resistivity, on multiwalled carbon nanotubes(MWNT) for field electron emitter source that had been screen printed in a thick film form were made as a function of temperature T in the range of 1.7K-390K. In this measuring temperature range, the electrical resistivity for the MWNT show that the main contribution to the conductivity comes form carries that hop directly between localized states executing variable range hopping processes. This thick-film form system for large area display showed a high bright light emission as well as very low turn-on field as like an individual MWNT system at room temperature. Furthermore, the electron emission characteristics followed well typical Fowler-Nordheim conduction under the vacuum.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.790-795
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• 1998

Fabrication of inverted staggered power TFT devices and electrical characteristic were investigated. 16 fingers with drain and source electrode of TFT and 100V output voltage were designed successfully. It is observed that as $V_g$ increased, $I_d$ increase exponentially. Because of localized deep states of a-Si, $I_d$ shows irregular variation at low voltage. Output and transfer characteristic showed the same as typical variation. But electrical characteristic strongly depend on the channel length and thickness of silicon nitride and amorphous silicon.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.9
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• pp.771-774
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• 2003

In this paper, the programming characteristics of the multi-bit devices based on SONOS structure are investigated. Our devices have been fabricated by 0.35 $\mu\textrm{m}$ complementary metal-oxide-semiconductor (CMOS) process with LOCOS isolation. In order to achieve the multi-bit operation per cell, charges must be locally frapped in the nitride layer above the channel near the source-drain junction. Programming method is selected by Channel Hot Electron (CUE) injection which is available for localized trap in nitride film. To demonstrate CHE injection, substrate current (Isub) and one-shot programming curve are investigated. The multi-bit operation which stores two-bit per cell is investigated. Also, Hot Hole(HH) injection for fast erasing is used. The fabricated SONOS devices have ultra-thinner gate dielectrics and then have lower programming voltage, simpler process and better scalability compared to any other multi-bit storage Flash memory. Our programming characteristics are shown to be the most promising for the multi-bit flash memory.

• The Journal of the Acoustical Society of Korea
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• v.21 no.4
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• pp.156-156
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• 2002

We apply independent component analysis (ICA) for extracting an optimal basis to the problem of finding efficient features for representing speech signals of a given speaker The speech segments are assumed to be generated by a linear combination of the basis functions, thus the distribution of speech segments of a speaker is modeled by adapting the basis functions so that each source component is statistically independent. The learned basis functions are oriented and localized in both space and frequency, bearing a resemblance to Gabor wavelets. These features are speaker dependent characteristics and to assess their efficiency we performed speaker identification experiments and compared our results with the conventional Fourier-basis. Our results show that the proposed method is more efficient than the conventional Fourier-based features in that they can obtain a higher speaker identification rate.

• Proceedings of the KIEE Conference
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• 2007.04b
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• pp.146-148
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• 2007

We studied the partial discharge detecting by sensing electromagnetic wave emitted from the partial discharge source in the MV XLPE cable with the new type of patch antenna sensor. In this study, we design new kind of Patch antenna and make many experiments compare with the existing HFCT sensor on MV XLPE cable in the laboratory. According to our experimental results our new sensor can defect pure PD and wider bandwidth 20MHz to 70MHz than HFCT and can easily localized manually on the cable.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.6
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• pp.783-788
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• 2002

Bovine yolk sac at day 24 of pregnancy, and placental membranes (chorion and allantois) from days 70 and 100 of pregnancy were isolated and cultured in a modified minimum essential medium in the presence of $[^{35}S]$methionine. Proteins synthesized and secreted by isolated bovine yolk sac, chorion and allantois were analyzed by fluorography of two-dimensional polyacrylamide gel electrophoresis. Serum-like proteins,transferrin, ${\alpha}$-fetoprotein, ${\alpha}$1-antitrypsin and ${\alpha}$1-acid glycoprotein,were the major protein products of yolk sac. A 21 kDa protein produced by yolk sac was identified immunochemically as retinol-binding protein (RBP). Chorion and allantios from days 70 and 100 of pregnancy were active in protein synthesis and secretion. Both chorion and allantois did not secret serum-like proteins but secreted a number of neutral-to-acidic proteins including RBP. Secretory proteins produced by the yolk sac, chorion and allantois may play important roles in the embryonic development and the successful outcome of pregnancy. Antiserum against bovine placental RBP was employed to the immunocytochemistry by immunoperoxidase method. Immunoreactive RBP was localized in epithelial cells and island-like cell clones of yolk sac. Immunostaining for RBP was detected in simple columnar epithelium of chorion and in simple squamous epithelium of allantois. In the present study, proteins synthesized and secreted by yolk sac at day 24 of pregnancy, chorion and allantois from days 70 and 100 of pregnancy were characterized In addition, RBP was localized in yolk sac, chorion and allantois by immunoperoxidase method. The immunoperoxidase method has been proven to be a very effective technique to identify the cellular source of protein synthesis in extraembryonic membranes.

• The Journal of the Petrological Society of Korea
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• v.15 no.2 s.44
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• pp.81-89
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• 2006

Pb isotopic compositions were determined from the ore deposits of Beonam, Dongjin, Jeoksang and Bukchang mines distributed within Jeolabuk-do. As a result, individual mine shows significantly different values of Pb isotopic compositions from each other. Pb isotopic values of the Beonam, Bukchang and Dongjin mines altogether from linear variation, but it is too steep to represent their formation age. Instead, such trend suggests that these ore leads were originated from binary mixing. Precambrian basement rocks and Mesozoic granitoids are suggested for such two end-members. The relative contribution of lead from each source seems to be quite different for each ore deposit, implying that the circulation of the ore-forming fluid was very localized when they were formed. In the case of Dongjin mine it seems significant portion of the ore leads were originated from the basement rocks, which suggests that related igneous rock seems to have acted as heat source to generate circulation of the fluid rather than the source of the ore-forming elements.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.1
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• pp.71-77
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• 2005

In this paper we implement a headphone-based 5.1 channel 3-dimensional (3D) sound generation system using HRTF (Head Related Transfer Function). Each mono sound source in the 5.1 channel signal is localized on its virtual location by binaural filtering with corresponding HRTFs, and reverberation effect is added for spatialization. To reduce the computational burden, we reduce the number of taps in the HRTF impulse response and model the early reverberation effect with several tens of impulses extracted from the whole impulse sequences. We modified the spectrum of HRTF by weighing the difference of front-back spec01m to reduce the front-back confusion caused by non-individualized HRTF DB. In informal listening test we can confirm that the implemented 3D sound system generates live and rich 3D sound compared with simple stereo or 2 channel down mixing.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.447-452
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• 2012

Among the various elements affecting a customer's evaluation of automobile quality, buzz, squeak and rattle (BSR) are considered to be major factors. In most vehicle manufacturers, the BSR problems are solved by find-fix method with the vehicle road test, mainly due to various excitation sources, complex generation mechanism and subjective response. The aim of this paper is to develop the integrated experimental method to systematically tackle the BSR problems in early stage of the vehicle development cycle by resolving these difficulties. To achieve this aim, the developed experimental method ought to include the following requirements: to find and fix the BSR problem for modules instead of a full vehicle in order to tackle the problem in the early stage of the vehicle development cycle; to develop the exciter system including the zig and road-input-signal reproducing algorithm; to automatically localize the source region of BSR; to develop sound quality index that can be used to assess the subjective responses to BSR. Also, the BSR sound quality indexes based on the Zwicker's sound quality parameters using a multiple regression analysis. The four sound metrics from Zwicker's sound quality parameter are computed for the signals recorded for eight BSR noise source regions localized by using the acoustic-field visualized results. Then, the jury test of BSR noise are performed for participants. On a basis of the computed sound metrics and jury test result, sound quality index is developed to represent the harsh of BSR noise. It is expected that the developed BSR detection system and sound quality indexes can be used to reduce the automotive interior BSR noise in terms of subjective levels as well as objective levels.