Earticle

In this study, tunable dielectric materials are important for resonator, variable capacitor, phased array antenna and other devices application. In this paper, Dielectric constant increased and tuning range increased with the increased of $BaSrTiO_3/Li_{2}CO_{3}$ content, which probably can be explained by the substitution of Ba3+, Li1+ on BaTiO3 lattice. The tunability and dielectric loss of the $BaSrTiO_2/Li_{2}CO_{3}$ thick film, sintered at $1150^{\circ}C$, were about 43 % and 0.234 at 10$\sim$15 MHz, respectively. In case of BaSrTi/MgO, Dielectric constant decreased and tenability increased with the added of $BaSrTiO_3/MgO$. The ferroelectrics properties were distinct when adding Li to BST ceramic thick film, and paraelectrics pattern was distinct when adding Mg.

In this paper, Effect of $BaSrTiO_3/Li_2CO_3$ on low temperature sintering and dielectric property of thick films has been investigated for variable capacitor on high frequency. The thick films were fabricated by the tape casting and then the structural and dielectric properties as a function of an addition composition ratio and sintering temperature were studied. For the thick film sintered at $1050^{\circ}C$, it was densified to 96% of $BaSrTiO_3$ theoretical density by the addition of 10 $wt{\cdot}%$ $BaSrTiO_3/Li_2CO_3$. Dielectric constant increased and Curie temperature lowered with the increased of $BaSrTiO_3/Li_2CO_3$ content, which probably can be explained by the substitution of $Ba^{3+},Li^{1+}$ on $RaTiO_3$ lattice. The tunability and dielectric loss of the $BaSrTiO_3/Li_2CO_3$ thick film, sintered at $1350^{\circ}C$, were about 26% and 0.234 at $10{\sim}15MHz$, respectively.

최근에 위성용 필터로서 유전체 공진기 내장 도파관 필터가 많이 연구되고 있다. 이 필터의 튜닝을 위하여 튜닝 스크류가 일반적으로 사용되어져 왔는데 튜닝 스크류의 사용은 복잡한 필터의 튜닝 시 너무 소모적인 작업을 야기시키고 미세한 튜닝에 어려움이 있어서 다른 해결책을 필요로 한다. 또한 제품의 사용 시에는 온도등의 외부환경의 변화에 대하여 대처를 하기 위하여 전기적인 튜닝을 이용한 튜닝의 자동화에 대한 필요성이 대두되었다. 이에 대한 해결책으로 BST($Ba_xSr_{1-x}TiO_3$)라는 강유전체를 이용하는 튜닝에 대하여 소개하고 한 경우에 대하여 FDTD 방시의 EM 시뮬레이션을 구하여 그 결과로서 전기저인 필터 튜닝의 가능성을 보여준다.

동적 메모리 관리는 컴퓨터 시스템의 중요하고 본질적인 동작이다. 메모리를 얼마나 효율적으로 이용 하느냐에 따라 시스템의 성능이 달라진다. 따라서 본 논문에서는 실시간 시스템을 위해 보다 효율적으로 메모리를 사용하는 동적 메모리 할당 알고리즘, BHF(Binary-search-tree-Half-Fit)를 제안한다. 제안된 알고리즘은 메모리 요청을 위해 2 의 거듭제곱의 프리 블럭 리스트를 이진 탐색 트리로 사용한다. 제안된 알고리즘의 효율성을 나타내기 위하여 절반-적합 알고리즘과 이진 버디 시스템과 비교, 분석하였다.

The devices of BST thin films to composite (Ba$\_$0.7/ Sr$\_$0.3/)TiO$_3$using sol-gel method were fabricated by changing of the depositing layer number on Pt/Ti/SiO$_2$/Si substrate. The thin film capacitor to be ferroelectric devices was investigated by structural and electrical properties. The thickness of BST thin films at each coating numbers 3, 4 and 5 times was 2500[${\AA}$], 3500[${\AA}$], 3800[${\AA}$]. The dielectric factor of thin film when the coating numbers were 3, 4 and 5 times was 190, 400 and 460 on frequency 1[MHz]. The dielectric loss of BST thin film was linearly increased by increasing of the specimen area.

This paper was presented to BaTiO$_3$-SrTiO$_3$(BST) ceramic capacitor in using high voltage. Structural and electrical properties of BST ceramic capacitor were researched in accordance with SrTiO$_3$ contents. As the result of investigation, the BST1 ceramic capacitor was showed to stable dielectric properties between 25 and 85[$^{\circ}C$]. According as frequency was increased, relative permittivity was decreased because inner spontaneous polarizations were decreased. As supplied voltage was increased, relative permittivity of specimen was varied in 3.04 ~3.98[%].

In this paper, BST((Bao.&o,dTi0:3) thin films were deposited by the rf magnetron sputtering method on Pt/$SiO_2$/Si substrate. Pt, $RuO_2$, Ag, Cu films for the formation of top electrode were deposited on BST thm films. And then Top Electrodes/BST/Pt capacitors were annealed with rapid thermal annealing(RTA) at various temperature. We have investigated effect of post-annealing on the electrical properties such as dielectric constant and leakage current of the capacitors. It was found that electrical properties of the capacitors were greatly depended on the annealing temperatures as well as the materials of top electrodes. In BST thin films with Pt top electrode was annealed at $700^{\circ}C$. the dielectric constant was measured to the value of 346 at l[kHzl and the leakage current was obtained to the value of $8.76\times10^8$[A/$\textrm{cm}^2$] at the forward bias of 2[V].

본 논문은 핑거 (finger) 형 전극에 의해 증강된 가장자리 전계가 가변 캐패시터의 가변성을 개선시킬 수 있음을 보여주고 있다. 가장자리가 긴 전극을 설계하기 위해 면적과 선폭이 다른 finger 형태의 전극들이 설계되었다. 가변 바렉터들은 quartz 기판위에 para/ferro/para의 가변 다층 유전체 박막을 이용하여 제작되었다. 기존의 일반적인 가변 캐패시터와 비교해서, 핑거형 캐패시터들의 유효 용량와 가변성 특성을 분석하였다. 1~2.5 GHz에서 증강된 가장자리 전계로 인해 긴 가장자리 전극으로 설계된 가변 캐패시터의 유효 용량과 가변성이 각각 24~40 % 그리고 7~12 % 증가하였다.

This paper has presented that fringing-electric fields enhanced by a finger-type electrode can improve the tunability of the tunable capacitor. Its top electrodes with different area and line width are designed in types of the finger for a long conducting perimeter. The tunable varactors were fabricated on a quartz substrate employing a multi-layer dielectric of a para/ferro/para-electric thin film. Compared to the conventional capacitor, finger-type capacitors are analyzed in terms of effective capacitance and tunablility. Their effective capacitance and tunability of the varactors with the long perimeter increase 24~40 % and 7~12 %, respectively, due to enhanced fringing electric fields from 1 to 2.5 GHz.

본 연구는 과배란처리에 의한 수정란이식 시 우수한 수정란을 다량 확보하고 이식 후 수태율 향상을 위하여 공란우 및 수란우에 bST처리가 수정란회수를 및 수태율에 어떠한 영향을 미치는가를 조사하고자 실시하였다. 공란우는 Folltropin-V와 PGF$_2$$\alpha$를 이용하여 과배란처리를 유도하여 12시간 간격으로 2 straw치 3회 인공수정을 실시하였다. 공란우와 수란우는 대조구와 bST처리구로 구분하였으며, bST(500 mg)처리는 발정발현 후 미근부에 근육주사하였다. 과배란처리된 공란우의 수정란배란을 수정 후 7~8일째에 비와과적인 방법으로 실시 하였다. 이식가능 수정란의 회수율과 평균숫자는 대조구와 bST처리구 간에 유의적인 차이가 없었다 (72.8%/5.9$\pm$4.5 vs. 83.7%/5.1 $\pm$1.6; P<0.05). 비여름철에 이식가능 수정란의 회수율과 평균숫자가 여름철보다 유의적으로 높았다(81.8%15.4$\pm$2.1 vs. 68.7%14.7$\pm$4.6; P<0.05). 수정란이식 후 수태율은 bST처리구에서 대조구보다 유의적으로 높았다 (64.0 vs. 47.1%; P<0.05). 그러나 이식 후 수태율에 계절간에 유의적인 차이는 없었다(51.6 vs.61.5%; P>0.05). 본 연구결과에서 bST처리는 수정란이식 후 수태율의 향상시킬 수 있을 것으로 판단되며, 비여름철이 과배란처리 및 수정란이식에 유리할 것으로 판단된다.

The purpose of this study was to determine the effect of bST treatment on embryo recovery and pregnancy rate following embryo transfer. Donor cows were superovulated with Folltropin-V and PGF$_2$$\alpha$ combination method and then inseminated with frozen semen 3 times 12 hrs interval. Donor and recipient cows were assigned to control and bST group, of which was given a single injection of bST (500 mg, im) at insemination or estrus detection. Embryo collection of superovulated cows were flushed nonsurgical method at 7 to 8 days after artificial insemination. The percentare and Mean$\pm$S.E. of transferable embryo was not significantly different between control and bST treatment (72.8%/5.9$\pm$4.5 vs. 83.7%15.1 $\pm$ 1.6). The percentage and Mean$\pm$S.E. of transferable embryo in non-summer season was significantly higher than in summer (81.8%/5.4$\pm$2.1 vs. 68.7%14.774.6; P<0.05). The pregnancy rate after embryo transfer in bST treatment was significantly higher than in control (64.0 vs. 47.1%; P<0.05). There was no significant difference in pregnancy rate between summer and non-summer (51.6 vs. 61.5%; P>0.05). The results indicated that InST treatment in recipient cows could improve the efficiency of transferable embryo production and pregnancy rate after embryo transfer, and non-summer season may be better far superovulation treatment and embryo transfer.

Effects of recombinant bovine somatotropln(${\gamma}$BST) on hematologie and blood chemical values were investigated in twenty-five multiparous Holstein dairy cows. Recombinant BST was administered by two different routes ; intramusculary(12.5mg and 25mg/day) and subcutaneously(500mg and 750mg) in sustained-release vehicle every 2 weeks beginning 4 weeks postpartum and continuing for 7 months. Whole blood and serum samples were collected 0, 1, 2, 3, 5, and 7 months after beginning of treatments from control and ${\gamma}$BST-administered groups. Hematologic values including RBC, PCV, HB, MCH, MCHC, WBC and differential counts of treatment groups receiving ${\gamma}$BST were similiar to those of control group. Blood chemical values observed were total protein, albumin, A/G ratio, glucose, cholesterol, Ca, Pi, Ca/pi ratio, total bilirubin, creatinine, BUN, alkaline phosphatase, lactate dehydrogenase, alanine aminotransferase and aspartate aminotransferase. There were no significant differences in blood chemical values of cows administered with ${\gamma}$BST from those of control. Although some blood chemical values were fluctuated at a certain observation period, they were remained within the normal physiological ranges. It is concluded from the observations of these experiments that the dose and dosage froms of ${\gamma}$BST employed in this work might not affect hematologic and blood chemical values in dairy cows under the normal sanitary condition and adequate nutritional balance.