• 한국전산유체공학회:학술대회논문집
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• 2008.08a
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• pp.40.4-41
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• 2008

• 한국전산유체공학회:학술대회논문집
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• 2008.08a
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• pp.68.4-68.4
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• 2008

• ETRI Journal
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• v.35 no.3
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• pp.425-430
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• 2013

In this paper, we propose a triple-gate trench power MOSFET (TGRMOS) that is made through a modified RESURF stepped oxide (RSO) process, that is, the nitride_RSO process. The electrical characteristics of TGRMOSs, such as the blocking voltage ($BV_{DS}$) and on-state current ($I_{D,MAX}$), are strongly dependent on the gate configuration and its bias condition. In the nitride_RSO process, the thick single insulation layer ($SiO_2$) of a conventional RSO power MOSFET is changed to a multilayered insulator ($SiO_2/SiN_x/TEOS$). The inserted $SiN_x$ layer can create the selective etching of the TEOS layer between the gate oxide and poly-Si layers. After additional oxidation and the poly-Si filling processes, the gates are automatically separated into three parts. Moreover, to confirm the variation in the electrical properties of TGRMOSs, such as $BV_{DS}$ and $I_{D,MAX}$, simulation studies are performed on the function of the gate configurations and their bias conditions. $BV_{DS}$ and $I_{D,MAX}$ are controlled from 87 V to 152 V and from 0.14 mA to 0.24 mA at a 15-V gate voltage. This $I_{D,MAX}$ variation indicates the specific on-resistance modulation.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.5
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• pp.383-392
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• 2007

In this paper, we study the prediction of depth and width of a defect in steam generator tube in nuclear power plant using neural network. To this end, we first generate eddy current testing (ECT) signals for 4 defect patterns of SG tube: I-In type, I-Out type, V-In type, and V-Out type. In particular, we generate 400 ECT signals for various widths and depths for each defect type by the numerical analysis program based on finite element modeling. From those generated ECT signals, we extract new feature vectors for the prediction of defect size, which include the angle between the two points where the maximum impedance and half the maximum impedance are achieved. Using the extracted feature vector, multi-layer perceptron with one hidden layer is used to predict the size of defects. Through the computer simulation study, it is shown that the proposed method achieves decent prediction performance in terms of maximum error and mean absolute percentage error (MAPE).

• The Korean Journal of Malacology
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• v.4 no.1
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• pp.1-16
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• 1988

The authors observed histochemical and ultrastructural characters on the osphradium of Rapana venosa Valenciennes using light microscope, scanning and transmission electron microscpes. The results were as follows:1)The basic structure of osphradium was bipectinated shape, which consisted of a septum situating in the center of osphradium and numerous osphradial leaflets. On the other hand, Epidermis of ospradial leaflets formed the structure of pseudostratified ciliated columnar epithelium which was composed of an epithelial cell layer, a basal cel layer and a neuropile. 2) Ciliated dpithelial cells:A large number of these cells were observed on the lateral and ventral regions but a small number of them were observed on the dorsal region. These cells had cylindrical microvilli, slender mitochondria and serve fibers.3) Supporting cells: These cells had cylindrical microvilli, spongy layer, electron dense granules, mitochondria and nerve fibers4) Four types secretory epothelial cells: Four distinct types of secretory epithelial cells were recognized and were arbitrily designated as Type I, Type II, Type III and Type IV.cell type I: These cells contained electron denwe granules(diameter, 0.94-1.56${\mu}{\textrm}{m}$), well developed Golgi apparatus and rough endoplasmic reticula, cell type II: These cills contained two types of granules of the different electron density. One was high electron density granules which were 0.4-1.0${\mu}{\textrm}{m}$ in diameter, The other was low electron density granules which were 0.75-1.2${\mu}{\textrm}{m}$ in diameter.cell type III:These cells had fibrous secretory materials and exhibited strongly positive reaction with Toluidine blue.cell type IV:A large number of this type of cells were observed on the ventral region of ospgradial leaflets and positively reacted with periodic acid Schiff reagent. 5)Dark cells contained several electron dense cillaty rootlets and unmerous granules but cellular organelles were not observed.6) Four types basal cells: Four distinci types of basal cells were recognized and arbitrarily designated as Type I, Type II, Type III and Type IV.Cell type I(light cell): These cells exhibited low electuon density and contained short smooth endoplasmic reticula, several vacuoles and granules.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.1
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• pp.1-7
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• 2000

In this paper, we present n-channel GaAs MOSFET having $Al_2O_3$ as gate in insulator fabricated on a semi-insulating GaAs substrate. 1 ${\mu}$m thick undoped GaAs buffer layer, 1500 ${\AA}$ thick n-type GaAs, undoped 500 ${\AA}$ thick AlAs layer, and 50 ${\AA}$ GaAs caplayer were subsequently grown by molecular beam epitaxy(MBE) on (100) oriented semi-insulating GaAs substrate oxidized. When it was wet oxidized, AlAs layer was fully converted $Al_2O_3$. The I-V, $g_m$, breakdown charateristics of the fabricated GaAs MOSFET showed that wet thermal oxidation of AlAs/GaAs epilayer/S${\cdot}$I GaAs was suitable in realizing depletion mode GaAs MOSFET.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.5
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• pp.602-608
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• 2011

In this study, a method of designing a neurointerface using neural network (NN) is proposed for controlling nonholonomic mobile robots. According to the concept of virtual master-slave robots, in particular, a partially stable inverse dynamic model of the master robot is acquired online through the NN by applying a feedback-error learning method, in which the feedback controller is assumed to be based on a PD compensator for such a nonholonomic robot. The NN for the online feedback-error learning can composed that the input layer consists of six units for the inputs $x_i$, i=1~6, the hidden layer consists of two hidden units for hidden outputs $o_j$, j=1~2, and the output layer consists of two units for the outputs ${\tau}_k$, k=1~2. A tracking control problem is demonstrated by some simulations for a nonholonomic mobile robot with two-independent driving wheels. The initial q value was set to [0, 5, ${\pi}$].

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.342-349
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• 2019

We describe and anlayzes the methodology and implementation results of H / W configuration and signal characteristics analysis algorithm for analyzing equipment for analyzing OFDMA physical layer based on 802.16e. Recently, demand for signal analysis of instruments that analyze these signals with the development of digital communication signals is rapidly increasing. Accordingly, it is necessary to develop signal analysis equipment capable of analyzing characteristics of a broadband communication signal using a wideband digital signal processing module. In this paper, we have studied the basic theory of OFDMA in order to devise a device capable of analyzing characterisitcs of broadband communication signals. Second, the structure of OFDMA transmitter/receiver was examined. Third, a wideband digitizer was implemented. we design Wimax signal analysis algorithm based on OFDMA among broadband communication methods and propose Wimax physical layer analysis S/W implementation through I, Q signals. The IF downconverter used the receiver module and the LO generation module of the spectrum analyzer. Quantitative analysis result is obtained through the algorithm of Wimax signal analysis by I, Q data.

• Journal of the Korean Society of Clothing and Textiles
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• v.44 no.3
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• pp.427-440
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• 2020

This study developed a vest prototype capable of monitoring body temperature using textile electrodes to prevent the sudden death of babies as well as to determine the quality of developed products by evaluating usability with commercial products. Based on the results of the 7th Size Korea Project, a basic pattern for a vest prototype was drafted by applying the average size of two-year-old Korean babies. Two prototypes were the detachable (VEST I) and integrated textile electrodes vest type (VEST II), which followed the same design. The materials were 100% cotton single jersey (SJ) and double jersey (DJ). Six experts evaluated the usability of the developed vests (VEST I & VEST II) and commercial product (VEST M). The single-layer woven textile electrode appeared to have a slightly higher conductivity than the double-layer one. There was no statistical difference in the body temperature sensing function between VEST I and VEST II. Finally, the superiority of the VEST I was verified through a comparison with commercial products (VEST M). The usability test suggested that a wearable smart clothing system of the integrated conductive textile could be further commercialized for bio-monitor applications in Ubiquitous-health care.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.4
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• pp.291-299
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• 2000

Morphine or butorphanol was continuously infused into cerebroventricle (i.c.v.) with the rate of $26\;nmol/{\mu}l/h$ for 3 days, and the withdrawal from opioid was rendered 7 hrs after the stopping of infusion. The expression of physical dependence produced by these opioids was evaluated by measuring the naloxone-precipitated withdrawal signs. The withdrawal signs produced in animals dependent on butorphanol (kappa opioid receptor agonist) were similar to those of morphine (mu opioid receptor agonist). Besides the behavioral modifications, opioid withdrawal affected G protein expression in the central nervous system. The G-protein ${\alpha}-subunit$ has been implicated in opioid tolerance and withdrawal. The effects of continuous infusion of morphine or butorphanol on the modulation of G protein ${\alpha}-subunit$ mRNA were investigated by using in situ hybridization study. In situ hybridization showed that the levels of $G\;{\alpha}s$ and $G\;{\alpha}i$ were changed during opioid withdrawal. Specifically, the level of $G\;{\alpha}s$ mRNA was decreased in the cortex and cerebellar granule layer during the morphine and butorphanol withdrawal. The level of $G\;{\alpha}i$ mRNA was decreased in the dentate gyrus and cerebellar granule layer during the morphine withdrawal. However, the level of $G\;{\alpha}i$ mRNA was significantly elevated during the butorphanol withdrawal. These results suggest that region-specific changes of G protein ${\alpha}-subunit$ mRNA were involved in the withdrawal from morphine and butorphanol.