• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.273-276
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• 2003

High-temperature superconduction materials(Bi2223) possess electrical/electronic and magnetic properties. Because high-temperature superconduction materials is a ceramic powder, that can not be produced singlehandedly. So Ag sheathed Bi-2223 wire was produced by drawing process using powder-in-tube(PIT) method. This superconductor has many difficulties to produce. The main difficulty is that the mechanical properties of the ceramic powder are very different from those of the Ag sheath. Bi2223 high-temperature superconductivity have a single filament drawing process, and multi-filament drawing process. This study analysed multi-filament drawing process by FEM, a defects during multi-filament drawing was studied by FEM.

• 소성∙가공
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• 제13권1호
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• pp.78-83
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• 2004

High-temperature superconduction materials(Bi2223) possess electrical/electronic and magnetic properties. Because high-temperature superconduction materials is a ceramic powder, that cannot be produced singlehandedly. So Ag sheathed Bi-2223 wire was produced by drawing process using powder-in-tube(PIT) method. This superconductor has many difficulties to produce. The main difficulty is that the mechanical properties of the ceramic powder are very different from those of the Ag sheath. And by these properties, Bi2223 high-temperature superconductor, which has a single filament drawing process and multi-filament drawing process, has a defect like sausaging and bursting at a center. This study analyzed multi-filament drawing process by FEM, and a defect generated during multi-filament drawing was studied by FEH. Specially, in order to prevent a bursting at a center, this study presented a method that inserts a pure Ag at a center of multi-filament wire

• 한국시뮬레이션학회논문지
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• 제11권2호
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• pp.17-29
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• 2002

There is an increasing interest in high-performance A/D(Analog-to-Digital) converters for use in integrated analog and digital mixed processing systems. Pipeline A/D converter architectures coupled with BiCMOS process technology have the potential for realizing monolithic high-speed and high-accuracy A/D converters. In this paper, the design of 12bit pipeline BiCMOS A/D converter presented. A BiCMOS operational amplifier and comparator suitable for use in the pipeline A/D converter. Test/simulation results of the circuit blocks and the converter system are presented. The main features is low distortion track-and-hold with 0-300MHz input bandwidth, and a proprietary 12bit multi-stage quantizer. Measured value is DNL=${\pm}$0.30LSB, INL=${\pm}$0.52LSB, SNR=66dBFS and SFDR=74dBc at Fin=24.5MHz. Also Fabricated on 0.8um BiCMOS process.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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• pp.262-267
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• 2000

To tap the possibility of exploiting the precipitates as flux-pinning center in the Bi-2223 superconducting system, as-received Bi-2223/Ag tapes with the starting composition of Bi$_{1.8}$Pb$_{0.4}$Sr$_2$Ca$_{2.2}$Cu$_3$O$_8$ were post-annealed at various temperature, oxygen partial pressure, and annealing time. The 2$^{nd}$ phases in the annealed specimen were analysed with XRD, SEM, TEM, and EDS. The size and the distribution of the precipitates such as (Ca,Sr)$_2$(Pb,Bi)O$_4$ and Bi$_{0.5}$Pb$_3$Sr$_2$Ca$_2$CuO$_{12+{\delta}}$ (3221) in the Bi-2223 matrix was controllable by varying heat-treatment condition without breaking the connectivity of the 2223 grains. The nano-size precipitates within the 2223 grains are conjectured as working as flux-pinning sites, resulting in increased J$_c$ value.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.298-298
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• 2007

Influence of $TiO_2$ on the dielectric properties of the $Bi(Nb_{0.7}Ta_{0.3})O_4$ ceramic with 7 wt% zinc borosilicate(ZBS) glass was investigated as a function of the $TiO_2$ contents with a view to applying this system to LTCC technology. The $Bi(Nb_{0.7}Ta_{0.3})O_4$ ceramic addition of 7 wt% ZBS glass ensured successful sintering below $900^{\circ}C$. But, TCF of $Bi(Nb_{0.7}Ta_{0.3})O_4$ ceramic is large negative values, respectively, it is necessary to adjust to zero TCF for practical applications Therefore, the addition of materials having positive TCF, such as $TiO_2$, might be an effective method for the improvement. In general, increasing addition of $TiO_2$ increased dielectric constant and TCF but it decreased the sinterability and $Q{\tiems}f$ value significantly due to the dielectric property and high sintering temperature of $TiO_2$. $Bi(Nb_{0.7}Ta_{0.3})O_4$ ceramic with 7 wt% ZBS glass and then addition 0.5 wt% $TiO_2$ sintered at $900^{\circ}C$ demonstrated 42 in the dielectric constant(${\varepsilon}_r$), 1,000 GHz in the $Q{\times}f$ value, and $10{\pm}5\;ppm/^{\circ}C$ in the temperature coefficient of resonant frequency(${\tau}_f$).

• Transactions on Electrical and Electronic Materials
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• 제8권5호
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• pp.201-205
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• 2007

Low temperature sintering behavior and microwave dielectric properties of the $BiNbO_{4^-}$ and the $ZnNb_2O_{6^-}zinc$ borosilicate glass(ZBS) systems were investigated with a view to applying the composition to LTCC technology. The addition of $10{\sim}30$ wt% ZBS in both systems ensured successful sintering below $900^{\circ}C$. For the $BiNbO_{4^-}ZBS$ system, the sintering was completed when 15 wt% ZBS was added whereas 25 wt% ZBS was necessary for the $ZnNb_2O_{6^-}zinc$ system. Secondary phase was not observed in the $BiNbO_{4^-}ZBS$ system but a small amount of $ZnNb_2O_6$ with the willemite structure as the secondary phase was observed in the $ZnNb_2O_{6^-}ZBS$ system. In terms of dielectric properties, the application of the $BiNbO_{4^-}$ and the $ZnNb_2O_{6^-}ZBS$ systems sintered at $900^{\circ}C$ to LTCC were shown to be appropriate; $BiNbO_{4^-}15$ wt% ZBS($\varepsilon_r=25,\;Q{\times}f\;value=3,700GHz,\;\tau_f=-32ppm/^{\circ}C$) and $ZnNb_2O_{6^-}25$ wt% ZBS($\varepsilon_r=15.8,\;Q{\times}f\;value=5,400GHz,\;\tau_f=-98ppm/^{\circ}C$).

• 대한수학교육학회지:수학교육학연구
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• 제20권3호
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• pp.397-411
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• 2010

이 연구에서는 우리나라 초등학교 수학에서 취급하는 비율과 비의 값의 정의를 비판적으로 분석하였다 또, 이 과정에서 할푼리의 정체를 재조명하였다. 비율과 관련해서는, 두 수에 대한 비율은 생각하지 않고, 또 비율이라는 용어의 사용을 비교하는 양과 기준량의 단위가 같은 경우로 한정할 것을 제안한다. 비율의 정의로는 '비교량이 기준량의 몇 배인가를 나타내는 수'를 사용할 것을, 비의 값의 정의로는 '비 A : B의 값을 A/B라고 한다.'를 사용할 것을 제안한다. 할푼리는 학교수학에서 사용할 목적으로 할, 푼, 리를 합쳐 만든 조어이다. 할푼리에 해당하는 원래 용어는 보합이지만, 이 연구에서는 보합을 사용하는 대신, 할푼리를 정의 제안한다. 할푼리가 보합의 순화어이고, 할푼리를 비율 표시 방법이 아니라 비율로 본다는 점에서, '기준량을 10으로 볼 때익 비율'을 할푼리의 정의로 사용할 것을 제안한다. 또, 할, 푼, 리를 '할푼리를 나타내는 단위'로, 비율을 나타내는 (소수) 0.1을 1할, 0.01을 1푼, 0.001을 1리라고 할 것을 제안한다.

• E2M - 전기 전자와 첨단 소재
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• 제10권5호
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• pp.434-439
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• 1997

It this paper, the piezoelectric and electro-induced strain properties of (P $b_{1-}$2x/3/B $i_{x}$ )[N $i_{1}$3/N $b_{2}$3/)$_{0.4}$( $Ti_{0.6}$Z $r_{0.4}$)$_{0.6}$] $O_3$ceramics (x=0, 0.005, 0.02) were investigated with the substitution of B $i^{3+}$, and the feasibility of the application for bimorph actuator was evaluated by measuring the dynamic properties of the piezoelectric bimorph fabricated with above ceramics. Dielectric constant was enhanced with the increase of B $i^{3+}$ substitution, and appeared the maximum value of 5032 at x=0.01 composition. Increasing the substitution of B $i^{3+}$, the electromechanical coefficient( $k_{p}$ , $k_{31}$ ) was increased up to the substitution of 0.5 mol% B $i^{3+}$, showed the value of 0.656, 0.439, respectively. The piezoelectric constant( $d_{33}$ $d_{31}$ ) had the highest value of 344, 825 with the substitution of 0.5 mol% B $i^{3+}$. The strain, generated by 60 Hz AC electric field, had the largest value of 1200($\times$10$^{-6}$ $\Delta$1/1) in the composition with the substitution of 0.5 mol% B $i^{3+}$. The dynamic properties of the bimorph actuator, fabricated with the composition substitution of 0.5 mol% B $i^{3+}$, showed the largest value of 325 $\mu$m at $\pm$150 V square pulse. square pulse.are pulse..

• 전기학회논문지
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• 제60권11호
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• pp.2093-2096
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• 2011

In this study, lead-free $(Na_{0.5}K_{0.5})NbO_3-BiTiO_3$ ceramics were fabricated by a conventional mixed oxide method. Structural and electrical properties of lead-free $(Na_{0.5}K_{0.5})NbO_3$ ceramics with the variation of $BiTiO_3$ were investigated. The results of X-ray diffraction analysis showed a typical polycrystalline perovskite structure without presence of the second phase in all specimens. Sintered density increased with an increasing of BTO and the specimen added with 0.07 mol% of $BiTiO_3$ showed the maximum value of 97.8%. Average grain size decreased and densification increased with an increasing of $BiTiO_3$ contents. The electromechanical coupling factor of the 0.01 mol% $BiTiO_3$ doped NKN specimens was 0.32. Dielectric constant, dielectric loss and Curie temperature of the 0.07 mol% $BiTiO_3$ doped NKN specimens were 1185, 0.145% and $400^{\circ}C$, respectively.

• 동의신경정신과학회지
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• 제4권1호
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• pp.135-153
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• 1993

In order to observe clinical effects of Kwi-Bi-Tang(歸脾湯) and Sa-Mul-An-Shin-Tang(四物安神湯), I reached following conclusion through the physiochemical investigation the following results obtained. 1)In serum Lipid, only Total cholesterol is significantly decresed in medication group of Kwi-Bi-Tang(歸脾湯), but is not in the medicaton of Sa-Mul-An-Tang(四物安神湯). 2). The value of Cardiac enzyme is remarkably decreased in the medication group of Kwi-Bi-Tang(歸脾湯), Only AST is significantly decresed in the medication group of Sa-Mul-An-Tang(四物安神湯). 3) In determination of LDH isoenzyme, LDI is significantly decrease both in the medication group of Kwi-Bi-Tang(歸脾湯) and Sa-Mul-An-Shin-Tang(四物安神湯). Especially, LDI is remarkably decreased in the medication group of Kwi-Bi-Tang(歸脾湯). In view of the results so far achieved, we knew that Kwi-Bi-Tnag(歸脾湯) and Sa-Mul-An-Shin_Tang(四物安神湯) had improved ischemic condition of cardiac muscle, specially, Kwi-Bi-Tnag(歸脾湯) was significant compared to Sa-Mul-An-Shin-Tang(四物安神湯).