• E2M - 전기 전자와 첨단 소재
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• 제8권1호
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• pp.56-63
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• 1995

MESFETs of the Ti/Au and Ti/Pd/Au gate were fabricated on n-type GaAs. Interdiffusion at Schottky interfaces, Schottky contact properties, and MESFET characteristics with heat treatment were investigated. Ti of Ti/Au contact and Pd of Ti/Pd/Au contact acted as a barrier metal against interdiffusion of Au at >$220^{\circ}C$. Pd of Ti/Pd/Au contact acted as a barrier metal even at >$360^{\circ}C$, however, Ti of Ti/Au contact promoted interdiffusion of Au instead of role of barrier metal. As the heat treatment temperature increases, in the case of both contact, saturated drain current and pinch off voltage decreased, open channel resistance increased, and degree of parameter variation in Ti/Au gate was higher than in Ti/Pd/Au gate at >$360^{\circ}C$ Schottky barrier height of Ti/Au and Ti/Pd/Au contacts was 0.69eV and 0.68eV in the as-deposited state, respectively, and Fermi level was pinned in the vicinity of 1/2Eg. As the heat treatment temperature increases, barrier height of Ti/Pd/Au contact increased, however, decreased at >$360^{\circ}C$ in the case of Ti/Au contact. Ideality factor of Ti/Au contact was nearly constant regardless of heat treatment, however, increased at >$360^{\circ}C$ in the case of Ti/Au contact. From the results above, Ti/Pd/Au was stable gate metal than Ti/Au.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1823-1826
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• 2002

The purpose of this experiment was to develope Triggered Vacuum Switch (TVS) for the high voltage and high current. The TVS has an array of rods of alternate polarity in which a fixed gap spacing is maintained between the rods. The cross section of each rod has trapezoidal shape. It consists of electrode, ceramic chamber, getter and trigger. Currently, triggered vacuum switch (TVS) with seal-off has been designed and fabricated at PAL. An experimentation and trigger devices for TVS were designed for testing characteristics of electricity. For making the prototype of TVS, it is developed of fabrication process and fined of electrode material. The fabrication of the TVS is a lot of process which have manufacturing of part, chemical clean, ceramic brazing and metal welding. The fabricated TVS is tested of leak for vacuum, hold-off voltage and conditioning of trigger system. The TVS has pinch-off after it is removed of gas in the TVS and activated of getter in degassing furnace. The prototype TVS tested about 20 kV, 75 kA, 83 ${\mu}s$ with 100 kJ capacitor bank and inductance 5 ${\mu}H$. This paper describes the results of tests and the characteristics of the switch.

• Restorative Dentistry and Endodontics
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• 제24권4호
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• pp.614-622
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• 1999

Recent studies have implicated that more rostral components of the trigeminal spinal nucleus including subnucleus oralis (Vo) in orofacial nociceptive mechanisms. Since there is only limited electrophysiological evidence, the present study was initiated to characterize the receptive field and response properties of malls nociceptive neurons in chloralose/urethan-anesthetized rats. Single neuronal activity was recorded in right subnucleus oralis, and types of nociceptive neurons classified wide dynamic range (WDR), NS (nociceptive specific) and deep nociceptive (D) and the mechanoreceptive field (RF) and response properties were determined. A total of 34 nociceptive neurons could be subdivided into 17WDR neurons, 12NS neurons and 5D neurons. Vo nociceptive neurons had RF involving maxillary and/or mandibular divisions mainly located in the intraoral and/or perioral regions. Majority of Vo nociceptive neurons showed spontaneous activity less than 1Hz. The NS and D neurons activated only by heavy pressure and/or pinch stimuli had high mechanical thresholds compared to WDR neurons activated also by tactile stimuli. Vo nociceptive neurons showed a progressive increase of response to the graded mechanical stimuli. 39% of Vo nociceptive neurons received C-fiber electrical input as well as A-fiber electrical input from their RF, and 45% of them responded to electrical stimulation of the right maxillary first molar. 41% of Vo nociceptive neurons responded to noxious heat applied to their RF, and 18% of them showed an immediate burst of discharges following MO application to the right maxillary first molar pulp. These results indicate that Vo is involved in the transmission of nociceptive information mainly coming from intraoral or perioral region including tooth pulp.

• 한국전기전자재료학회논문지
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• 제33권4호
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• pp.281-285
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• 2020

Oxide semiconductor devices have become increasingly important because of their high mobility and good uniformity. The channel length of oxide semiconductor thin film transistors (TFTs) also shrinks as the display resolution increases. It is well known that reducing the channel length of a TFT is detrimental to the current saturation because of drain-induced barrier lowering, as well as the movement of the pinch-off point. In an organic light-emitting diode (OLED), the lack of current saturation in the driving TFT creates a major problem in the control of OLED current. To obtain improved current saturation in short channels, we fabricated indium gallium zinc oxide (IGZO) TFTs with single gate and double gate structures, and evaluated the electrical characteristics of both devices. For the double gate structure, we connected the bottom gate electrode to the source electrode, so that the electric potential of the bottom gate was fixed to that of the source. We denote the double gate structure with the bottom gate fixed at the source potential as the BGFP (bottom gate with fixed potential) structure. For the BGFP TFT, the current saturation, as determined by the output characteristics, is better than that of the conventional single gate TFT. This is because the change in the source side potential barrier by the drain field has been suppressed.

• PNF and Movement
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• 제20권2호
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• pp.147-156
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• 2022

Objective: Electrical stimulation is an assistive technology used to aid the recovery of upper limb use after stroke. The purpose of this systematic review was to determine the effects of electrical stimulation on upper extremity function in individuals with hemiparetic stroke and to develop an evidence base that supports the use of electrical stimulation for upper limb recovery after stroke. Design: A systematic review based on randomized controlled trials (RCTs). Methods: Studies published before April 20 2021 were collected for this review by searching PubMed, four other databases, and RCTs that reported the effects of electrical stimulation on upper extremity function in individuals with the characteristic stroke type. Information on the following parameters was extracted from each study: surname of first author, published year, country, participants, intervention, intervention's intensity, comparison, outcomes, additional therapy, and summary of results. This review also evaluated the bias within each study, including any selection bias, performance bias, detection bias, attrition bias, and reporting bias. Results: This review included five RCTs, and 208 stroke patients were included in the analysis. Stroke patients who underwent electrical stimulation showed significantly improved grip and pinch strengths, wrist range of motion, and basic daily living compared to those in the control group; however, there was no improvement in upper extremity function. Of the selected papers, 60% showed a "high risk" of performance bias, and 20% showed a "high risk" of detection bias. Conclusions: The results of this systematic review suggest that electrical stimulation provides some benefits to stroke patients, such as improved hand strength and range of motion. However, future studies are needed to provide clinical evidence of the effects of electrical stimulation on upper extremity function in stroke patients.

• 대한전자공학회논문지SD
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• 제38권6호
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• pp.383-389
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• 2001

본 논문에서는 밀리미터파 대역에서 응용 가능한 AIGaAs/InGaAs PHEMT를 제작하고 특성을 분석하였다. 제작에 사용된 PHEMT 웨이퍼는 ATLAS 시뮬레이터를 이용하여 DC 및 RF 특성을 최적화 하였다. 게이트 길이가 0.35 ㎛이고 서로 다른 게이트 폭과 게이트 핑거 수를 갖는 PHEMT를 전자빔 노광장치를 이용하여 제작하였다. 제작된 소자의 게이트 길이와 핑거수에 따른 RF 특성변화를 측정 분석하였다. 게이트 핑거 수가 2개인 PHEMT의 DC 특성으로 1.2 V의 무릎 전압, -1.5 V의 핀치-오프 전압, 275 ㎃/㎜의 드레인 전류 밀도 및 260.17 ㎳/㎜의 최대 전달컨덕턴스를 얻었다. 또한 RF 특성으로 35 ㎓에서 3.6 ㏈의 S/sub 21/ 이득, 11.15 ㏈의 MAG와 약 45 ㎓의 전류 이득 차단 주파수 그리고 약 100 ㎓의 최대 공진주파수를 얻었다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제10권3호
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• pp.213-224
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• 2010

An optically controlled silicon MESFET (OPFET) was fabricated by diffusion process to enhance the quantum efficiency, which is the most important optoelectronic device performance usually affected by ion implantation process due to large number of process induced defects. The desired impurity distribution profile and the junction depth were obtained solely with diffusion, and etching processes monitored by atomic force microscope, spreading resistance profiling and C-V measurements. With this approach fabrication induced defects are reduced, leading to significantly improved performance. The fabricated OPFET devices showed proper I-V characteristics with desired pinch-off voltage and threshold voltage for normally-on devices. The peak photoresponsivity was obtained at 620 nm wavelength and the extracted external quantum efficiency from the photoresponse plot was found to be approximately 87.9%. This result is evidence of enhancement of device quantum efficiency fabricated by the diffusion process. It also supports the fact that the diffusion process is an extremely suitable process for fabrication of high performance optoelectronic devices. The maximum gain of OPFET at optical modulated signal was obtained at the frequency of 1 MHz with rise time and fall time approximately of 480 nS. The extracted transconductance shows the possible potential of device speed performance improvements for shorter gate length. The results support the use of a diffusion process for fabrication of high performance optoelectronic devices.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.332-332
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• 2011

The extreme ultraviolet (EUV) radiation, whose wavelength is from 120 nm down to 10 nm, and the energy from 10 eV up to 124 eV, is widely utilized such as in photoelectron spectroscopy, solar imaging, especially in lithography and soft x-ray microscopy. In this study, we have investigated the plasma diagnostics as well as the debris characteristics between the two types of dense plasma focusing devices with coaxial electrodes of Mather and hypocycloidal pinch (HCP), respectively. The EUV emission intensity, electron temperature and plasma density have been investigated in these cylindrical focused plasma along with the debris characteristics. An input voltage of 5 kV has been applied to the capacitor bank of 1.53 uF and the diode chamber has been filled with Ar gas at pressure ranged from 1 mTorr and 180 mTorr. The inner surface of the cathode was covered by polyacetal insulator. The central anode electrode has been made of tin. The wavelength of the EUV emission has been measured to be in the range of 6~16 nm by a photo-detector (AXUV-100 Zr/C, IRD). The visible emission has also been measured by the spectrometer with the wavelength range of 200~1,100 nm. The electron temperature and plasma density have been measured by the Boltzmann plot and Stark broadening methods, respectively, under the assumption of local thermodynamic equilibrium (LTE).

• Archives of Reconstructive Microsurgery
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• 제17권2호
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• pp.101-107
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• 2008

Purpose: Free flaps from the great toe are an established method for reconstruction of absent or partially amputated thumbs. However, options differ as to which technique represents the ideal solution for each level of amputation. Various methods of distal thumb reconstruction have been proposed. We prefer to transplant the entire great toe nail complex with the almost all of the pulp rather than a portion of the nail. This paper reflects our experience in using the great toe mini wrap-around flap for distal thumb reconstruction. Materials and Methods: In the period from October of 2005 to July of 2007, 9 patients were treated for traumatic thumb defects localized at the distal phalanx of the thumb. The patients included seven men and two women. The mean age was 44 years (range, 21~60) and the dominant right hand was involved in seven of nine patients. Results: The transferred flaps have survived completely in all cases. The mean range of motion in the interphalangeal joints was 51o, with 73% of the normal uninjured opposite hands. The two-point discrimination was 10.5 mm (range, 5~13 mm). In Semmes-Weinstein monofilament test, the sensibility was 4.31 in 4 cases, 3.61 in 3 cases and 2.83 in 2 cases. The pinch power was 64% (range, 55~95%) of the opposite hand. All patients were satisfied with the appearance of the reconstructed thumb and felt comfortable at final follow-up. Conclusion: We have successfully reconstructed 9 cases of traumatic distal thumb defects using the mini wrap-around free flap. The mini wrap-around free flap in great toe is an excellent alternative method for distal thumb reconstruction in selected patients.

• 한국식품영양과학회:학술대회논문집
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• 한국식품영양과학회 2001년도 International Symposium on Food,Nutrition and Health for 21st Century
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• pp.69-73
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• 2001

Two opioid peptides, YPLDL and YPLDLF, were isolated from enzymatic digests of spinach ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO) and named rubiscolin-5 and -6, respectively. These peptides were selective for delta-receptor and the latter was about 3 times more potent than the former. After oral administration in mice at the dose of 100 mg/kg, rubiscolin-6 showed analgesic activity in tail pinch test. It also stimutated learning performance at the same dose in passive avoidance experiment using step-through apparatus. An immunostimulating peptide, MITLAIPVNKPGR, was isolated from a trypsin digest of soybean protein and named soymetide. Immunostimulating activy of soymetide was mediated by fMLP receptor. Interestingly, after oral administration in rats at a dose of 300 mg/kg (po.), soymetide-4 (MITL) protected alopecia (hair-loss) induced by etoposide, a cancer chemotherapy agent. Stimulation of IL-1 release by the peptide was involved in the mechanism. Ovokinin(2-7), RADHPF, is a vasorelaxing peptide released from ovalbumin by the action of chymotrypsin. It lowered blood pressure of spontaneously hypersensive rats (SHR) after oral administration at a dose of 10 mg/kg. RPLKPW, which was designed by replacing 4 amino acid residues in ovokinin(2-7), exhibited hypotensive activity at a dose of 0.1 mg/kg (po.). This peptides was introduced into 3 homologous sites in soybean beta-conglycinin alpha' subunit by site-directed mutagenesis of the cDNA and expressed in E. coli. The minimum effective dose for hypotensive activity of the genetically modified beta-conglycinin alpha' subunit was 10 mg/kg (po.), which is about 1/200 that of ovalbumin.