• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.28-28
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• 2010

This study realized low-temperature crystallization process of the $Ba_{0.6}Sr_{0.4}TiO_3$ (BST) thin films without thermal damage of substrate using excimer laser annealing (ELA) and structural and electrical characteristics were investigated. The amorphous BST thin films were prepared on Pt/Ti/$SiO_2$/Si substrate by sol-gel method at $250^{\circ}C$. The ELA was carried out using KrF excimer laser which provided excitation wavelength of 248 nm. The beam homogenizing system was used in order to homogenize beam shape of Gaussian fit. The XRD and SEM were used to analyze structural characteristics and the microwave capacitance, dielectric loss and tunability of the BST films were measured by a symmetrical stripline resonator method with shorted end. Consequently, the crystallinity of BST thin films were improved after ELA process and RF tunable capacitor was demonstrated at low temperature below $300^{\circ}C$.

• 한국전자파학회논문지
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• 제16권3호
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• pp.253-259
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• 2005

본 논문에서는 고가의 단결정 기판 대신에 저가의 실리콘 기판을 이용한 인터디지탈 구조의BaSrTiO$_{3}$(BST) 박막 가변 커패시터를 제안하였다. 저가의 실리콘 기판 위의 BST 박막은 PLD 장비를 이용하여 증착하였으며, 제작된 가변 커패시터는 4 GHz까지 측정되었다. 또한 최대 인가 전압은 50 V이며, 5 kV/cm 조건에서 약 30$\%$ 정도의 가변율을 얻는다. 저가의 실리콘 기판 위에 BST 박막을 증착, 커패시터를 구현함으로써 BST 박막을 이용한 가변 소자들을 집적화할 수 있는 가능성을 보였다.

• 한국세라믹학회지
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• 제42권2호
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• pp.123-126
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• 2005

용매열법으로 출발물질의 농도를 변수로 차여 $BaTiO_3$ 분말을 합성하였다. 평균입자크기는 출발물질의 농도에 따라 비례하였는데 TiO_2를 기준으로 1/16M 농도에tj 59nm이었고 1/2M 농도에서는 89nm까지 증가하였다. 평균입자 크기가 89nm인 BT 분말에 대하여 리트벨트법에 의하여 분석한 결과 상분율은 정방정상 $75.5\%$이었고, 격자상수는 정방정상은 a=0.3999(nm), c=0.40319(nm)이고, 입방정상은 a=0.4015(nm)이었다. 이 분말을 $500^{\circ}C$ 1시간 열처리 후 TEM분석을 한 결과, 분말 내부에 수산 이온들이 거의 존재하지 않음을 확인하였다.

• 한국미생물·생명공학회지
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• 제14권3호
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• pp.219-223
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• 1986

사람 선유아세포 인터페론의 정제에 사용되는 단 clone성 항체생산 세포주를 조작하기 위하여 BA-LB/C mouse의 복강과 꼬리정맥을 통하여 HuIFN-$\beta$를 면역화시키고 그 비장세포(spleen cells) 와 NS-O 세포주를 세포융합 시켰다. 융합된 1300 hybrids를 ELISA방법으로 선별하고 soft agarose 방법과 limiting dilution방법으로 subcloning하여 높은 항체를 생성하는 것으로 판명된 11 hybrids를 재선별 하였다. 재선별된 11 hybrids 각각의 항체형 (Ig type)을 조사하고 최종 Protein A-sepharose와 친화성이 높은 IgG 2a/형의 clone # 4-1-19와 clone # 551-4-1을 선별하여 배양된 세포를 각각 nude(nu/nu) mouse 및 BALB/c mouse 복강에 접종배양 하였다. 이들 mouse복강액으로 부터 얻은 ascites fluid를 protein A-sepharose를 이용한 affinity column분획으로 항체를 정제하였으며 ascites fluid $m{\ell}$당 약 4mg의 정제된 항체를 얻을 수 있었고 SDS-polyacrylamide gel상에서 전기영동 시킨 결과 분자량 14-16만 dalton으로 추정되는 항체를 확인할 수 있었다.

• Progress in Superconductivity
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• 제8권1호
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• pp.93-97
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• 2006

YBCO films were deposited on a moving substrate by a spray pyrolysis method using nitrate aqueous solution as precursors. Deposition was made on $LaAlO_3$(100) single crystal substrate by spraying precursor droplets generated by a concentric nozzle. The cation ratio of precursor solution was Y:Ba:Cu=1:2.65:4.5. The distance between nozzle and substrate was 15 cm. Substrate was transported with a speed ranging from 0.23 cm/min to 0.5 cm/min. Films were deposited at the pressure ranging from 10 Torr to 20 Torr and the deposition temperature was ranged from $740^{\circ}C\;to\;790^{\circ}C$. Oxygen partial pressure was controlled between 1 Tow and S Torr. Superconducting YBCO films were obtained from $740^{\circ}C\;to\;790^{\circ}C$ with an oxygen partial pressure of 3 Torr. Scanning electron microscope(SEM) and X-ray diffraction(XRD) observation revealed that films are smooth and highly texture with(001) plans parallel to substrate plane. Highest Jc was 0.72 $MA/cm^2$ at 77K and self-field for the film with a thickness of 0.15 m prepared at a substrate temperature of $740^{\circ}C$ and $PO_2$=3 Torr.

• Progress in Superconductivity
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• 제8권1호
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• pp.59-64
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• 2006

High $J_c\;YBa_2Cu_3O_x$ superconducting films were fabricated by MOD method using fluorine-free dichloroacetic acid(DCA) as chelating solvent for preparing precursor solution. Coating solutions were prepared by dissolving Y-, Ba- and Cu-acetates in DCA solvent followed by drying in rota vapor to obtain the blue gel that is diluted in methanol and 2-methoxyethanol for adjusting the cation concentration. DCA-MOD precursor solution was coated on a single crystal(001) $LaAlO_3(LAO)$ substrate by a dip coating method with a speed of 25 mm/min. Coated films were calcined at lower temperature up to $500^{\circ}C$ in flowing oxygen atmosphere with a 7.2% humidity. Conversion heat treatment was performed at various temperatures of $780{\sim}810^{\circ}C$ for 2 h in flowing Ar gas containing 1000 ppm oxygen with a humidity of 9.45%. SEM observations showed that films have very dense microstructures for the films prepared at the temperature higher than $800^{\circ}C$ regardless of diluting solvent; methanol or 2-methoxyethanol. X-ray diffraction analysis showed that YBCO grains grew with a (001) preferred orientation. A High critical current density($J_c$) of 1.28 $MA/cm^2$(@77 K and self-field) was obtained id. the YBCO film prepared using 2-methoxyethanol as a solvent.

• 생약학회지
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• 제49권2호
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• pp.155-164
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• 2018

Nypa fruticans Wurmb is a species of palm, which is widely distributed in the mangrove forest of Southeast Asia. Various parts of N. fruticans has been used as a traditional medicinal plant. However, the physiological activities of N. fruticans has not yet been clarified well. Therefore, in this study, the 50% ethanol extract and its aqueous and ethyl acetate fractions of young shoots of N. fruticans were investigated for their antioxidant, cytoprotective effect, and antimicrobial activities. Every sample possessed very high free radical and various ROS scavenging capacities assessed by employing different in vitro assays such as $DPPH^{\cdot}$, $O_2^{{\cdot}-}$, ${\cdot}OH$, and $^1O_2$ scavenging activities. Based on these results, the cytoprotective effect was investigated using the oxidative hemolysis of erythrocyte. We found that the extract and fractions provide a greater protective effect compared with (+)-${\alpha}$-tocopherol. Furthermore, antimicrobial activities were confirmed against skin pathogens by broth microdilution assay. The ethyl acetate fraction had much higher antimicrobial activities than methyl paraben against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Candida albicans. Taken together, our results indicated that the young shoots of N. fruticans may have the potential role as a natural active ingredient through their antioxidant, cytoprotective effect, and antimicrobial activities.

• 대한약침학회지
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• 제23권1호
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• pp.30-36
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• 2020

Objectives: The objective of the study was to prepare Bauhinia variegata loaded nanoemulsion(formulation and determine the efficacy of herbal drug formulation against diabetic peripheral neuropathic pain through acupuncture technique. Methods: Nine different ba tches of nanoemulsion (NE1 NE9) of BVN was prepared by varying the S_mix ratio and the concentration of oil. BVN was characterized to determine particle size, shape, zeta potential, polydispersity index, optical transmittance, drug release profile and stora ge stability. The optimized formulation was subjected to plantar test, behavioral tests of neuropathic pain and Von Frey filament stimulation test. Diabetes was induced by intraperitoneal injection of freshly prepared solution of Streptozotocin (60 mg/kg) to the experimental rats. Animals were made diabetic divided into four groups, Group I was untreated normal control group, Group II was diabetic control group, Group III was Bauhinia variegata extract ( treated group (100 mg/kg/day, p.o) and Group IV was BVN treated groups (100 mg/kg/day, p.o) acute and chronically. Results: The prepared B. variegata loaded nanoemulsion was nanosized (124 nm), spherical, uniform and stable over the period of 180 days with no change in physiochemical properties. The bl ood glucose and body weight of animals was normalizing after four weeks of treatment that was significant with BVN in comparison to diabetic control group. The chronic administration of BVN significantly (P<0.001) decreased hind paw withdrawal latency an d attenuated mechanical allodynia as compared with diabetic rats. Conclusion: Thus, BVN may be an effective drug formulation against diabetic peripheral neuropathic pain.

• 공업화학
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• 제24권6호
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• pp.611-615
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• 2013

본 연구에서는 바나듐 산화물($VO_2$)과 텅스텐이 도핑된 바나듐 산화물(W-$VO_2$) 분말을 바나듐 산화물($V_2O_5$)과 옥살산수화물로부터 수열합성과 하소공정을 통하여 성공적으로 제조하였다. 시료들의 결정구조와 열변색 특성들은 FE-SEM, XRD, XPS, DSC 및 UV-Vis-NIR 분광기를 이용하여 분석하였다. W-$VO_2$ 시료에 W의 도핑량을 증가시키면, W-$VO_2$ 시료의 상전이 온도가 $70^{\circ}C$에서 $42^{\circ}C$로 낮아지는 경향이 있었다. 또한, W-$VO_2$ 시료를 상전이 온도 이상으로 가열시키면 UV-Vis-NIR 곡선이 가시광 영역에서는 변하지 않고 NIR 영역에서는 낮은 투과도 방향으로 이동하는 경향이 있었다.

• 한국초전도ㆍ저온공학회논문지
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• 제16권4호
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• pp.21-25
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• 2014

In order to develop 2nd generation (2G) high-temperature superconducting (HTS) wires as commercial products, it is necessary to perform a high speed investigation of their superconducting performance. Room-temperature and non-contact optical scanning tools are necessary to verify the microstructure of the superconducting materials, the current flow below the critical temperature, and the critical current density. In this paper, we report our results of an inspection of the electrical transport properties of coated conductors. The samples that we used in our study were highly qualified rare-earth based coated conductors produced via co-evaporation, and $SmBa_2Cu_3O_{7-y}$ (SmBCO) was the superconducting materials used in our studies. A film grown on IBAD-MgO templates shows larger than 400 A/cm at 77 K and a self-field. The local transport properties of the films were investigated by room-temperature imaging by thermal heating. The room-temperature images show structural inhomogeneities on the surface of the films. Bolometric response imaging via low-temperature bolometric microscopy was used to construct the local current mapping at the surface. These results indicate that the non-uniform regions on the surface disturb the current flow, and laser scanning images at room-temperature and at a low-temperature suggest a correlation between the structural properties and transport properties. Thus this method can be effective to evaluate the quality of the coated conductors.