• 호남수학학술지
• /
• 제40권3호
• /
• pp.391-400
• /
• 2018

The object of this paper to construct a new class $$A^m_{{\mu},{\lambda},{\delta}}({\alpha},{\beta},{\gamma},t,{\Psi})$$ of bi-univalent functions of complex order defined in the open unit disc. The second and the third coefficients of the Taylor-Maclaurin series for functions in the new subclass are determined. Several special consequences of the results are also indicated.

• 수산해양기술연구
• /
• 제30권4호
• /
• pp.350-356
• /
• 1994

We have prepared superconducting Bi-Pb-Sr-Ca.Cu-O thin films by RF magnetron sputtering technique, on heated MgO(100) substrates. Sputtering was carried out in a mixture of argon and oxygen(10%) and the pressure was maintained at 5 mTorr during deposition. The substrate temperature was maintained $400^{\circ}C$ during deposition. The films sputtered were amorphous and insulating. All the films became superconducting by annealing, The films annealed at $880^{\circ}C$ for 30 minutes in air showed high-Tc phase with zero resistivity of 93K. These results indicate that the growth of the high-Tc phase is promoted by the presence of Pb at annealing temperature.

• 한국초전도ㆍ저온공학회논문지
• /
• 제6권1호
• /
• pp.43-48
• /
• 2004

This paper deals with design and fabrication of heater-triggered switching system for the high-Tc superconducting (HTS) power supply with series-connected double-pancake load. Amongst all components, heater triggering is the most important element for the performance of HTS power supply. To fabricate the optimal heater-triggered system, its characteristics have been analysed through the simulation and expriment. The thermal analysis of switching parts of the Bi-2223 solenoid according to the heater input was carried out. Based upon the analysis, 8A electromagnet current and 1.5A DC Heater current were optimally derived, and 8s and 20s for the pumping period were selected in this experiment. In the experiment. the maximum pumping current reached about 24A with Bi-2223 pancake load of 6mH.

• 한국마이크로전자및패키징학회:학술대회논문집
• /
• 한국마이크로전자및패키징학회 2003년도 기술심포지움 논문집
• /
• pp.68-71
• /
• 2003

The reaction of ultra-small eutectic 58Bl-42Sn solder bump with Au/Ni/Ti and Au/Cu/Ti UBMs during reflow was studied. The eutectic Bi-Sn solder bumps of $46{\mu}m$ diameter were fabricated by using the evaporation method and were reflowed using the rapid thermal annealing system. The intermetallic compound was characterized using a SEM, an EDS, and an XRD. The $(Cu_xAu_{1-x})_6Sn_5$ compounds formed at the interface between Bi-Sn solder and Au/Cu/Ti UBM. On the other hand, in the Bi-Sn solder bump on Au/Ni/Ti UBM, the faceted and rectangular intermetallic compounds were observed on the solder bump surface and inside the solder bump as well as at the UBM interface. These intermetallic compounds were Identified as $(Au_{l-x-y}Bi_xNi_y)Sn_2$ phase.

• 한국초전도저온공학회:학술대회논문집
• /
• 한국초전도저온공학회 2000년도 KIASC Conference 2000 / 2000년도 학술대회 논문집
• /
• pp.3-5
• /
• 2000

Among the various processing techniques used in HTS wire fabrication, the PIP(Powder In Tube) method is currently one of the most promising for applications on an industrial scale. In this study, we have fabricated Bi-2223/Ag superconducting tapes using the modified PIT process, where several process factors were changed and improved, ie., powder packing, drawing, rolling and heat treatment. We obtained Bi-2223 tape that have high critical current, 46 a at 77.3 K, have high critical current, 46A at 77.3 K, self field although the tape was not pressed but only rolled. The critical current of 100m class long length tape was measured 21.6A at the same criterion. Besides, the critical current of Bi-2223/Ag tape was measured applying magnetic fields with different directions at various temperatures.

• E2M - 전기 전자와 첨단 소재
• /
• 제10권4호
• /
• pp.320-326
• /
• 1997

The stability of Bi-based superconducting wires cooled by a cryocooler was studied by considering the temperature dependency of critical current and electrical resistivity. The critical current measured in 23 K was about 7 times higher than that measured in liquid nitrogen of 77 K. The stability behavior of Bi based multifilament wires subjected to a thermal disturbance, which was simulated with a electric heater, was investigated by measuring the variation of voltage drop with time. Current sharing was occurred, and recovery to superconductivity was measured in the wire after removing heater power.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 하계학술대회 논문집 C
• /
• pp.1339-1341
• /
• 1997

The various type Ag sheathed Bi-2223 tapes have been were fabricated by Powder-in-tube(PIT) process. The critical current density could be improved with the value of $23,000\;A/cm^2$(77 K, zero field) in the single concentric Bi-2223 tape. The bending property dependence of $I_c$ was improved in the double concentric Bi-2223 tape compared with single filamentary and single concentric one.

• Journal of Magnetics
• /
• 제11권3호
• /
• pp.147-150
• /
• 2006

We have fabricated three-dimensional magnetophotonic crystals based on $\alpha$-$SiO_2$ opal films. Opal thin films grown on glass substrates were filled with bismuth substituted iron garnet (Bi:YIG). Scanning electron microscopy data, optical and magnetic properties of the synthesized samples confirm the presence of the Bi:YIG contentin the opal lattice. It is shown that the samples exhibit the (111) stop band, and transmissivity of the threedimensional magnetophotonic crystals is defined by both the film lattice and the Bi:YIG content.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.592-592
• /
• 2013

We synthesized BiOI nanostructures with various doped-concentrations of Ag (0.1, 1.0, 5.0, 10.0 mol%) and Ti (1.0, 5.0, 10.0, 30.0, 50.0 mol%). They show spherical echinoid-like structures examined by scanning electron microscope. The BET surface areas were measured to be in the range of 40~70 $m^2$/g, which is reduced by doping. The indirect band gap was estimated to be 1.8 eV for undoped BiOI with no change and 1.0 eV increase upon Ag and Ti doping, respectively. The structures were further examined by X-Ray diffraction analysis, FT-IR, and photoluminescence. We also demonstrated adsorption and photocatalytic degradation performances for methyl orange and Rhodamine B on the echinoid-like BiOI structures.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2016년도 춘계학술대회
• /
• pp.696-697
• /
• 2016

본 논문은 5.25-GHz BiCMOS 저 잡음 증폭기를 위한 바이어스 회로를 제안한다. 이러한 회로는 1볼트 전원에서 동작하며, 저전압 및 저전력으로 동작하도록 설계되어 있다. 제안한 회로는 $0.18{\mu}m$ SiGe HBT BiCMOS로 설계하였다. 이러한 회로는 밴드 갭 참조회로 (band-gap reference circuit)를 사용하였다.