• 한국진공학회지
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• 제5권1호
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• pp.77-84
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• 1996

Silicon deposition by Penning discharge was carried out using a mixture of 5% $SiH_4/H_2$ and Ar gas, and the effects of the deposition conditions(gas mixing raito, substrate temperature. discharge power etc.) on the growth rate, crystallinity and morphology of the films deposited were investigated. The magnetic field(800 G) confined the plasma in the region between the two cathodes and enhanced the discharge current by a factor of a few hundreds below 1 mTorr. The magnetic field-enhanced plasma density resulted in a very large deposition rate of about 300 $\AA$/min at $SiH_4$ flow rate of 0.7 sccm and the substrate temperature of $800^{\circ}C$. Characterization of the films by Raman spectroscopy, X-ray diffraction, and scanning electron microscopy revealed that an epitaxial film with a smooth surface grows above 80$0^{\circ}C$, an amorphous film below $400^{\circ}C$, and a rough polycrystalline film at intermediate temperatures.

• Journal of Chest Surgery
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• 제56권5호
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• pp.336-345
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• 2023

Background: The objective of this study was to demonstrate the safety, efficacy, and feasibility of intraoperative monitoring of the recurrent laryngeal nerves during thoracoscopic and robotic 3-field esophagectomy. Methods: This retrospective analysis details our initial experience using intraoperative nerve monitoring (IONM) during minimally invasive 3-field esophagectomy. Data were obtained from a prospectively maintained database and electronic medical records. The study included all patients who underwent minimally invasive (video-assisted thoracic surgery/robotic) transthoracic esophagectomy with neck anastomosis. The patients were divided into those who underwent IONM during the study period and a historical cohort who underwent 3-field esophagectomy without IONM at the same institution. Appropriate statistical tests were used to compare the 2 groups. Results: Twenty-four patients underwent nerve monitoring during minimally invasive 3-field esophagectomy. Of these, 15 patients underwent thoraco-laparoscopic operation, while 9 received a robot-assisted procedure. In the immediate postoperative period, 8 of 24 patients (33.3%) experienced vocal cord paralysis. Relative to a historical cohort from the same institution, who were treated with surgery without nerve monitoring in the preceding 5 years, a 26% reduction was observed in the nerve paralysis rate (p=0.08). On follow-up, 6 of the 8 patients with vocal cord paralysis reported a return to normal vocal function. Additionally, patients who underwent IONM exhibited a higher nodal yield and a decreased frequency of tracheostomy and bronchoscopy. Conclusion: The use of IONM during minimally invasive 3-field esophagectomy is safe and feasible. This technique has the potential to decrease the incidence of recurrent nerve palsy and increase nodal yield.

• 한국세라믹학회지
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• 제39권2호
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• pp.171-177
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• 2002

본 연구에서는 DC bias가 인가된 유도결합형 플라즈마 열선 화학기상증착법을 이용하여 580$^{\circ}C$의 저온에서 탄소나노튜브를 수직 배향시켰다. 성장된 탄소나노튜브의 기판으로는 강화유리 위에 촉매층으로 Ni과 전도층으로 Cr을 300/200 ${\AA}$(Ni/Cr) 증착된 것으로 R-F magnetron sputtering을 이용하여 제작하였다. 성장 시 RF power와 DC bias power는 150W와 80W이며 텅스텐 필라멘트 power는 7∼8 A로 인가하였다. 성장된 탄소나노튜브는 속이 비어 있는 다중벽으로 이루어 졌으며 성장된 탄소나노튜브 끝단에는 금속 촉매로 보이는 Ni이 존재하는 것을 알 수 있었다. 탄소나노튜브는 흑연화도가 우수하며 그에 따라 탄소나노튜브의 전계 방출 특성도 우수하게 평가되었다. 성장된 탄소나노튜브의 구동 전압은 약 3 V/${\mu}m$이었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2163-2165
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• 2005

A pulsed laser ablation deposition (PLAD) technique has been used for producing fine particle as well as thin film at relatively low substrate temperatures. However, in order to manufacture and evaluate such materials in detail, motions of plume particles generated by laser ablation have to be understood and interactions between the particles by ablation and gas plasma have to be clarified. Therefore, this paper was focused on the understanding of plume motion in laser ablation assisted by Ar plasma at 50(mTorr). Two-dimensional hybrid model consisting of fluid and particle models was developed and three kinds of plume particles which are carbon atom (C), ion $(C^+)$ and electron were considered in the calculation of particle method It was obtained that ablated $C^+$ was electrically captured in Ar plasmas by strong electric field (E). The difference between motions of the ablated electrons and $C^+$ made E strong and the collisional processes active.

• Transactions on Electrical and Electronic Materials
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• 제9권4호
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• pp.151-155
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• 2008

Using pentacene field effect transistors (FETs) with Au source and drain electrodes, electron injection from the Au electrodes into the pentacene was investigated. The capacitance-voltage (C-V) and optical second harmonic generation (SHG) measurements were employed. Electron injection from the Au electrodes was suggested by the hysteresis behavior with the C-V characteristics and slowly decaying SHG signal under DC biasing, A mechanism of hole-injection assisted by trapped electrons is proposed. To confirm electron injection process, light-emitting behavior under the application of AC applied voltage was observed.

• 소성∙가공
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• 제8권3호
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• pp.253-253
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• 1999

Dense WC-10 vol.%Co composite was simultaneously synthesized with field-activated and pressure-assisted combustion synthesis (FAPACS) within several minutes in one step from elemental powders of W, C and Co. Combustion synthesis was carried out under the combined effect of an electric field and mechanical pressure. Under the application of 60MPa pressure and 3000A current on the reactants, the relative density of WC-10 vol.%Co composite was 98.4%. The fracture toughness and hardness of WC-10 vol.%Co were 8.6 MPa·$m^{1/2}$ and 1900 kg/mm², respectively.

• Journal of Chest Surgery
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• 제23권5호
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• pp.1021-1026
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• 1990

The patients with tracheal stenosis have become more increasing in recent due to the increased use of tracheostomy and assisted ventilation Anesthetic management during tracheal reconstruction is a concern to the anesthetist and the surgeon, who must share the airway as a operation field and at the same time provide good gas exchange. Multiple technique such as the tube ventilation system or C \ulcornerP bypass method have been recommended to achieve this goals. However, these methods have disadvantages of poor surgical exposure and hemorrhagic complication from using C \ulcornerP bypass The technique for HFJV was first described for bronchoscopy, and it involves positive-pressure breathing with high flow[40 \ulcorner60L/min] of oxygen This flow is directed to a semirigid catheter inserted in the endotracheal tube and the tracheal reconstruction can be done without interruption. From Dec. 1986 to July 1990 we have experienced 6 patients of tracheal stenosis necessitating circumferential resection and end to end anastomosis; 5 patients with tracheal stenosis following cuffed tracheostomy or intubation, a patient with tracheal stenosis due to invasive thyroid cancer. The specific advantages during tracheal reconstruction are unobstructed field during surgical reconstruction and good gas exchange through the procedure.

• 한국재료학회지
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• 제12권6호
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• pp.431-435
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• 2002

The dark current and photocurrent(PC) spectrum of Mg-doped GaN thin film were investigated with various bias voltages and temperatures. At high temperature and small bias, the dark current is dominated by holes thermally activated from an acceptor level Al located at about 0.16 eV above the valence band maximum $(E_v)$, The PC peak originates from the electron transition from deep level A2 located at about 0.34 eV above the $E_v$ to the conduction band minimum $(E_ C)$. However, at a large bias voltage, holes thermally activated from A2 to Al experience the field-in-duces tunneling to form one-dimensional defect band at Al, which determines the dark current. The PC peak associated with the transition from Al to $E_ C$ is also observed at large bias voltages owing to the extended recombination lifetime of holes by the tunneling. In the near infrared region, a strong PC peak at 1.20 eV appears due to the hole transition from deep donor/acceptor level to the valence band.

• 조명전기설비학회논문지
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• 제19권4호
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• pp.24-31
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• 2005

고본 논문에서는 시뮬레이션 기법을 통하여 RAD법을 Ar 플라즈마 상태에서 구동하도록 설정하였다. 이것은 플라즈마를 구성하는 요소들이 PLAD법에 의해 방출된 각 입자들에 어떠한 영향을 미치는가를 확인하고자 하였으며, 특히 방출된 입자들의 운동 에너지 및 밀도를 제어할 수 있을 것으로 기대되어지기 때문이다. Ar 플라즈마의 방전 공간내에서, RAD법에 의한 전자, 탄소 이온$(C^+)$ 및 탄소 원자(C)의 운동 과정을 보다 정확히 계산하기 위해서 입자 및 유체 모델을 융합한 1차원 하이브리드 모델을 계발하였다. 그 결과 쉬스 내에 형성되는 전위를 제어함으로써 기판에 도달하는 $C^+$의 밀도 및 에너지를 제어할 수 있는 것으로 기대되어졌다.

• 열처리공학회지
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• 제14권1호
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• pp.1-7
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• 2001

A method to simultaneously synthesize and consolidate the silicide $NiSi_2$ and the composite $NiSi_2$-20vol.%Nb from powders of Ni, Si, and Nb was investigated. Combustion synthesis was carried out under the combined effect of an electric field and mechanical pressure. The final density of the products increased nearly linearly with the applied pressure. Highly dense $NiSi_2$ and $NiSi_2$-20vol.%Nb with relative densities of up to 97% were produced under the simultaneous application of a 60MPa pressure and a 3000A current on the reactant powders. The respective Vickers microhardness values for these materials were 6.0 and 5.8 GPa. From indentation crack measurements, the fracture toughness values for $NiSi_2$ and $NiSi_2$-20vol.%Nb were calculated to be 3.3 and 4.7 $MPa{\cdot}m^{1/2}$, respectively.