• Title/Summary/Keyword: Ni/MgO.

Search Result 341, Processing Time 0.027 seconds

Bending Mode Multilayer Actuator Using Low Temperature Sintering Piezoelectric Ceramics (저온소결 세라믹을 이용한 밴더형 적층 액츄에이터의 제작)

  • Lee, Ju-Young;Kim, Sang-Jong;Kang, Chong-Yun;Kim, Hyun-Jai;Lee, Sang-Yoel;Yoon, Seok-Jin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2005.07a
    • /
    • pp.68-69
    • /
    • 2005
  • Low temperature ($\leq900^{\circ}C$) sintering piezoelectric ceramics $0.01Pb(Mg_{1/2}W_{1/2})O_3$-0.41Pb$(Ni_{1/3}Nb_{2/3})O_3-0.35PbTiO_3-0.23PbZrO_3+0.1wt%Y_2O_3+xwt%ZnO$ $(0{\leq}x{\leq}2.5)$ have been developed and investigated. The electromechanical coupling coefficient ($k_p$), piezoelectric constant ($d_{33}$), and mechanical quality factor ($Q_m$) have been measured to characterize the piezoelectric materials system. When 2.0 wt% ZnO is added, the properties of the system, $d_{33}$ = 559 pC/N, $k_p$ = 55.0 % and $Q_m$ = 73.4 are obtained which are very suitable for piezoelectric actuators. A bending mode multilayer actuator has been also developed using the materials which size is $27(L)\times9(W)\times1.07(t)mm^3$. The actuators are fabricated by multilayer ceramic (MLC) process and consist of24 layers and each layer thickness is $35{\mu}m$. At this time, the displacement of actuator was $100{\mu}m$ at 28V.

  • PDF

Studies on acid protease produced from Aspergillus tubingensis I (Aspergillus tubingensis의 acid protease에 관한 연구 I)

  • Chung, Yun-Su;Cho, Young;Han, Suk-Hyun
    • Korean Journal of Microbiology
    • /
    • v.20 no.3
    • /
    • pp.105-112
    • /
    • 1982
  • The strain of Aspergillus, 6368A, producing acid protease showing high activity was isolated from soil, as a result of wide research about mold group. This strain was identified as a species of Aspergillus tubingensis by the investigation of morphological characteristics. The change of the enzyme production under the various media and culture condition was also studied. The optimum pH and stability of crude acid protease are 2.5, 2.0~4.5 and the optimum temeprature and thermal inactivation waas shown $50^{\circ}C,\;55^{\circ}C$, respectively. From the result of the study on the effects of metal ions, it was found that $MnCl_2,\;CoCl_2,\;CuCl_2,\;SrCl_2,\;and\;NiCl_2$ slightly increased the enzyme activity, on the other hand $ZnCl_2,\;CaCl_2,\;MgCl_2,\;SLS,\;and\;KMnO_4$ decreased it.

  • PDF

Selective Transport of Lead(II) through a Bulk Liquid Membrane Using a Cooperative Carrier Composed of Benzylaza-12-crown-4 and Oleic Acid

  • Kazemi, Sayed Yahya;Shamsipur, Mojtaba
    • Bulletin of the Korean Chemical Society
    • /
    • v.26 no.6
    • /
    • pp.930-934
    • /
    • 2005
  • A chloroform membrane system containing a given mixture of benzylaza-12-crown-4 and oleic acid is introduced for the selective and efficient transport of $Pb^{2+}$ ion. The transport was capable of moving metal ions ‘up-hill’. In the presence of ${S_2O_3}^{2-}$ion as a suitable metal ion acceptor in the receiving phase, the amount of lead ion transport across the liquid membrane after 150 minutes is (95.0 ${\pm}$ 1.7)%. The selectivity and efficiency of lead transport from aqueous solution containing $Tl^+,\;Ag^+,\;Mg^{2+},\;Ca^{2+},\;Co^{2+},$ $Ni^{2+},\;Cu^{2+},\;Zn^{2+},\;Hg^{2+}$ and $Cd^{2+}$were investigated. In the presence of thiosulfate as a suitable masking agent in the source phase, the interfering effects of $Ag^+\;and\;Cu^{2+}$ were diminished drastically.

Studies on Growth Enviromental and Inorganic Components of Korean Native Tea Plants(Camellia sinensis O. kuntze) (한국(韓國) 자생차(自生茶)의 생육지 토양과 엽중 무기성분 함량)

  • Park, Jang-Hyun;Kim, Kwang-Sik
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.31 no.1
    • /
    • pp.25-32
    • /
    • 1998
  • To characterize the growth environment, inorganic composition and morphological chracteristics of leaves of Korean tea plant, soil and tea leaf samples were collected from 15 locations and analyzed. The chemical characteristics of soils were in range of pH 4.09~6.15, OM 23.9~72.6g/kg, available phosphate less than 300mg/kg, K $0.8{\sim}2.5cmol^+/kg$, Na $tr{\sim}0.17cmol^+/kg$, Ca $1.0{\sim}6.2cmol^+/kg$, and Mg $0.3{\sim}2.1cmol^+/kg$. The contents of Ni. Cr, Zn. Cu, Pb, and Cd were at the level less than natural content in upland soil. Most of the sample soils were sandy loamy and loamy texture. The native tea plants were mainly grown in bamboo thicket or in forest. The leaf sizes of tea plants were $6.85{\pm}1.75{\times}2.6{\pm}0.5cm$, lateral vein number $14.2{\pm}2.7$, and crenated number $58.5{\pm}11.2$, and the leaf color was thin to dark green. The contents of $NH_4{^+}$, $Na^+$, $K^+$, $Mg^{2+}$ and $Ca^{2+}$ in tea leaves were in range of 30.5~47.7, 45.5~164.5, 16,998~25,431, 1.590~2,392 and 1,085~1,958mg/kg, respectively. The contents of $F^-$, $Cl^-$, $NO_3{^-}$, $PO_4{^{3-}}$ and $SO_4{^{2-}}$ were in range of 21.2~63.2, 126.4~257.9, 108.5~185.9, 1,270~1.819, and $954{\sim}1,670mg/kg$, respectively. The leaf size of native tea plant grown widlly in Shunchun Changchun-ri, Hwasun Ssangbongsa, Kuryoi Chonunsa, Bosong Daewonsa and Namhae Boriam was as large as those of Yabukita. Japan cultiver, grown at Kangjin Jangwon tea field.

  • PDF

Geologic Report on the Goobong Limestone Mine (구봉석회석광산의 지질조사보고(地質調査報告))

  • Lee, Dai Sung
    • Economic and Environmental Geology
    • /
    • v.3 no.1
    • /
    • pp.17-24
    • /
    • 1970
  • The purpose of this report is to prepare a data for the economic evaluation on the Goobong Limestone Mine which is located at the south-eastern corner of the Yongchun Quadrangle scaled in 1:50,000. The accessibility from the mine to railroad was considered in two ways. One is to Dodam Station on Central Railway Line and the other is to reach Songjung-ni village which is near Sangyong Station on Hamback Railway Line. The distance of the former way is 26.7km and the later is 24.2km. Geologically the mine is situated near the base of the Greast Limestone Series which strikes generally $N25^{\circ}{\sim}30^{\circ}E$. The series comprises six different formations from older to younger; Pungchon Limestone Formation and Whajol Formation of Cambrian age, and Dongjum Quartzite Formation, Dumudong Formation, Maggol Limestone Formation and Goseong Formation of lower to middle Ordovician age. 82 samples; 48 from Pungchon Limestone Formation, 11 from Dumudong Formation, 15 from Maggol Limestone Formation and 8 from Goseong Formation, were taken from the series in the crossed direction to the general trend of the series as shown in geological map. They were chemically analyzed on the components of CaO, MgO, $SiO_2$, $R_2O_3(Al_2O_3+Fe_2O_3)$ and ignition loss as shown in table 2, table 3, table 4, and table 5. As seen from the tables, among the formations of the series, middle to upper parts of the Pungchon Limestone Formation and middle and upper parts of the Dumudong Formation have chemical composition as available source for the raw material of cement industry, not only that but also the part of the Pungchon Formation was highly evaluated as source for the flux of iron smelting and the raw material of carbide manufacturing because of its high purity of calcium carbonate.

  • PDF

Characterization of the Starch Degradation Activity of recombinant glucoamylase from Extremophile Deinococcus geothermalis (극한성 미생물Deinococcus geothermalis 유래 재조합 글루코아밀레이즈의 전분 분해 활성 특징)

  • Jang, Seung-Won;Kwon, Deok-Ho;Park, Jae-Bum;Jung, Jong-Hyun;Ha, Suk-Jin
    • Journal of Industrial Technology
    • /
    • v.39 no.1
    • /
    • pp.15-19
    • /
    • 2019
  • This work focused on characterization of the starch degradation activity from extremophile strain Deinococcus geothermalis. Glucoamylase gene from D. geothermalis was cloned and overexpressed by pET-21a vector using E. coli BL21 (DE3). In order to characterize starch degrading activity of recombinant glucoamylase, enzyme was purified using HisPur Ni-NTA column. The recombinant glucoamylase from D. geothermalis exhibited the optimum temperature as $45^{\circ}C$ for starch degradation activity. And highly acido-stable starch degrading activity was shown at pH 2. For further optimization of starch degrading activity with metal ion, various metal ions ($AgCl_2$, $HgCl_2$, $MnSO_4{\cdot}4H_2O$, $CoCl_2{\cdot}6H_2O$, $MgSO_4$, $ZnSO_4{\cdot}7H_2O$, $K_2SO_4$, $FeCl_2{\cdot}4H_2O$, NaCl, or $CuSO_4$) were added for enzyme reaction. As results, it was found that $FeCl_2{\cdot}4H_2O$ or $MnSO_4{\cdot}4H_2O$ addition resulted in 17% and 9% improved starch degrading activity, respectively. The recombinant glucoamylase from D. geothermalis might be used for simultaneous saccharification and fermentation (SSF) process at high acidic conditions.

Fabrification of Segmented Flat-Tubular SOFC cell (Segmented 평관형 SOFC 셀 제조)

  • Park, Sung-Tae;Choi, Byung-Hyun;Ji, Mi-Jung;Choi, Heon-Jin
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2010.06a
    • /
    • pp.137.1-137.1
    • /
    • 2010
  • SOFC cell 하나의 전위차는 약1.1V이기 때문에 발전용으로 사용하기 위해서는 수많은 단전지를 직렬로 연결하는 구조가 필요하다. 이러한 stack의 디자인에서 발생하는 문제를 획기적으로 개선한 형태가 하나의 지지체에 셀을 직렬로 연결함으로 전극의 선폭 및 단위 셀 간의 간격이 기존 평판형, 원통형에 비해 대폭 축소되어 전극 및 연결재의 저항손실을 최소화할 수 있는 Segmented형 SOFC이다. Segmented SOFC에 적용하기 위한 세라믹 다공성 지지체는 연료와 공기에서의 화학적 안정성, 셀의 구성소재와 반응이 없으며 열팽창계수가 유사해야하는 특성을 가져야하는데 그 중에서도 지지체로써 적절한 기계적 강도와 높은 가스투과도가 요구되어진다. 본 연구에서는 고온에서 안정한 Spinel의 MgAl2O4를 주성분으로 하는 다공성 지지체를 압출 성형하여 평관형으로 제조하였으며 활성탄을 기공형성제로 사용하여 연료의 공급이 원활하도록 약 30%의 기공율을 가지는 다공성 세라믹 지지체를 제조하였다. 제조된 세라믹 지지체에 연료극(NiO/YSZ), 전해질(TZ8Y), 공기극(LSM)을 코팅하여 실제 SOFC에 적용이 가능함을 확인하였다.

  • PDF

Microstructure and Piezoelectric Properties of PMW-PNN-PZT Ceramics with Bismuth Substitution (PMW-PNN-PZT 세라믹스의 Bismuth 치환에 따른 미세구조 및 압전 특성)

  • Kim, Yong-Jin;Yoo, Ju-Hyun;Shin, Dong-Chan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.29 no.6
    • /
    • pp.332-336
    • /
    • 2016
  • In this study, in order to develop the composition ceramics for ultrasonic sensor with high $d_{33}*g_{33}$, $Pb_{1-3x/2}Bix(Mg_{1/2}W_{1/2})_{0.03}(Ni_{1/3}Nb_{2/3})_{0.09}(Zr_{0.5}Ti_{0.5})_{0.88}O_3$(PMW-PNN-PZT) system ceramics were prepared using CuO as sintering aids. And then, their microstructure, piezoelectric and dielectric characteristics were systemetically investigated with bismuth substitution. The PMW-PNN-PZT ceramic specimens could be sintered at sintering temperature of $940^{\circ}C$ by adding sintering aids. At x=0.015 specimen, the density, electromechanical coupling factor($k_p$), dielectric constant, piezoelectric constant($d_{33}$) and piezoelectric figure of merit($d_{33}*g_{33}$) indicated the optimal properties of $7.90g/cm^3$, 0.67, 2,511, 628 pC/N, and $17.7pm^2/N$, respectively, for duplex ultrasonic sensor application.

Concentration of Heavy Metals in Natural Soils of Jeju Island, Korea (제주도 자연토양에서 중금속의 농도)

  • Kim, Se-Ra;Hyun, Sung-Su;Song, Sang-Taek;Lee, Min-Gyu;Kam, Sang-Kyu
    • Journal of Environmental Science International
    • /
    • v.24 no.2
    • /
    • pp.175-188
    • /
    • 2015
  • For 63 soil series distributed in Jeju Island, natural uncultivated soils in each soil series were collected, and their physicochemical properties and their concentrations of 19 heavy metals including 8 heavy metals which are regulated by Korean Soil Environment Conservation Law, were analyzed. Moreover, the correlations between physicochemical properties and heavy metal concentrations, and between heavy metal concentrations were analyzed. The heavy metals distributed in the higher concentrations and the lower concentrations with arithmetric mean value, were Mn(730 mg/kg) and Ba(493 mg/kg), and Hg(0.146 mg/kg) and Tl(0.096 mg/kg), respectively. The correlations between pH($H_2O$) and heavy metals(Hg, Ni, Co, Se), between pH(NaF) and heavy metals(Hg, Ba, Se, Tl), and between organic matter content and heavy metals(Hg, Tl) were significant at the 0.01 level. From the correlations between heavy metal concentrations, there were 22 where there were significant at the 0.01 level and they showed positive correlation. Among those, the heavy metals showing the correlation higher than r=0.5, were Sb-V(0.878), Mo-Sn(0.867), Co-V(0.654), Co-Sb(0.648), Be-Sn(0.546), and Sn-Tl(0.528).

A Geochemical Study on the Behaviors of Major and Trace Elements in the Ulsan Granite and Its Contact Serpentinite (울산화강암 및 인접 사문암 중 주/미량 원소의 거동에 관한 지화학적 연구)

  • Lee, Jae Yeong;Lee, In Ho
    • Economic and Environmental Geology
    • /
    • v.28 no.1
    • /
    • pp.53-67
    • /
    • 1995
  • Geochemical characteristics of iron-related Ulsan granite was studied in comparison with the Cretaceous granitoids from the metallogenic provinces of copper, lead-zinc and lead-zinc/molybdenum in the Gyeongsang Basin, and the variation of cheminal compositions at the Ulsan granite/serpentinite contact was investigated. Ulsan granite is plotted in the regions of granite and granodiorite of Streckeisen's diagram. It shows differentiation trend of calc-alkali magma, and the magmatic evolution from granodiorite to granite is consistant with the general crystallization path of the Cretaceous the granitoids in Gyeongsang Basin. Differentiation index(D.I.) of Ulsan granite is 86~95, which is higher than those of Jindong granites (D.I.=45~70) and Onjongri granites (D.I.=67~84), and there are differences in the content of some major and trace elements between Ulsan granite and other Cretaceous granitoids. At the Ulsan granite/serpentinite contact $SiO_2$, $K_2O$, $Na_2O$, $Al_2O_3$, Rb, Sr, Ba which are abundant in Ulsan granite decrease toward serpentinite, while T.Fe, MgO, Ni, Cr which are abundant in serpentinite decrease toward Ulsan granite. Therefore, the geochemical characteristics of Ulsan granite is applicable to distinguish iron province from different metallogenic provinces where other Cretaceous granitoids occur in the Gyeongsang Basin, and it is possible to find serpentinite which was intruded by granite on the basis of chemical variations.

  • PDF