• Title/Summary/Keyword: Specific resistance ($K_2'$)

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Initial Charge/Discharge of $LiCoO_2$ Composite Cathode with Various Content of Conductive Material for the Lithium ion Battery (리튬이온전지용 $LiCoO_2$정극의 도전재료에 따른 초기 충방전 특성)

  • Doh Chil-Hoon;Moon Seong-In;Yun Mun-Soo;Yun Suong-Kyu;Yum Duk-Hyung;Park Chun-Jun
    • Journal of the Korean Electrochemical Society
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    • v.2 no.3
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    • pp.123-129
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    • 1999
  • Initial electrochemical characteristics of $LiCoO_2$ electrode for lithium ion battery with various content of super s black as conductive material were evaluated through the charge/discharge with the potential range of 4.3V to 2.0V versus $Li^+/Li^+$. The rate of C/4 and C/2 by the 3 electrode test cell composed with an electrolytic solution of 1 mol/l $LiPF_6/EC+DEC(1:3\;by\; weight)$. Lithium was used as reference electrode. High impedance charge behavior was observed at early stage of charge. In the case of $3\%w/w$ of super s black as conductive material, the specific resistance of the high impedance releasing was $3.82\;{\Omega}\;{\cdot}\;g-LiCoCo_2$ at the current density of $0.5 mA/cm^2$, which corresponds 7 times of the specific resistance of electrode $(0.728 g-LiCoO_2)$. At second charge, the specific resistance of the high impedance releasing was 63 mn · g-Lico02, which corresponds 12eio of the specific resistance of electrode and only $1.7\%$ of that of the first charge. The first charge and discharge specific capacities at C/4 rate were 160-161 and $153\~155mAh/g-LiCoO_2$, respectively, to lead $95.4\~96.4\%$ of coulombic efficiencies and ca. $6 mAh/g-LiCoO_2$ of initial irreversible specific capacity. Specific resistance at the end of charge and rest showed low value at content of super s black between 2 and $7\%w/w$, which agreed with characteristics of irreversible specific capacity. Capacity densities were reduced by the increasing the content of conductive material. They were 447 and 431mAh/ml when 2 and $2.9\%w/w$ of super s black were used, respectively, at the rate of C/4.

Nitric Oxide Plays an Important Role in β-Aminobutyric Acid-Induced Resistance to Botrytis cinerea in Tomato Plants

  • Li, Rui;Sheng, Jiping;Shen, Lin
    • The Plant Pathology Journal
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    • v.36 no.2
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    • pp.121-132
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    • 2020
  • β-Aminobutyric acid (BABA) has consistently been reported to enhance plant immunity. However, the specific mechanisms and downstream components that mediate this resistance are not yet agreed upon. Nitric oxide (NO) is an important signal molecule involved in a diverse range of physiological processes, and whether NO is involved in BABA-induced resistance is interesting. In this study, treatment with BABA significantly increased NO accumulation and reduced the sensitivity to Botrytis cinerea in tomato plants. BABA treatment reduced physical signs of infection and increased both the transcription of key defense marker genes and the activity of defensive enzymes. Interestingly, compared to treatment with BABA alone, treatment with BABA plus cPTIO (NO specific scavenger) not only significantly reduced NO accumulation, but also increased disease incidence and lesion area. These results suggest that NO accumulation plays an important role in BABA-induced resistance against B. cinerea in tomato plants.

Formation of Ohmic Contact to AlGaN/GaN Heterostructure on Sapphire

  • Kim, Zin-Sig;Ahn, Hokyun;Lim, Jong-Won;Nam, Eunsoo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.292-292
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    • 2014
  • Wide band gap semiconductors, such as III-nitrides (GaN, AlN, InN, and their alloys), SiC, and diamond are expected to play an important role in the next-generation electronic devices. Specifically, GaN-based high electron mobility transistors (HEMTs) have been targeted for high power, high frequency, and high temperature operation electronic devices for mobile communication systems, radars, and power electronics because of their high critical breakdown fields, high saturation velocities, and high thermal conductivities. For the stable operation, high power, high frequency and high breakdown voltage and high current density, the fabrication methods have to be optimized with considerable attention. In this study, low ohmic contact resistance and smooth surface morphology to AlGaN/GaN on 2 inch c-plane sapphire substrate has been obtained with stepwise annealing at three different temperatures. The metallization was performed under deposition of a composite metal layer of Ti/Al/Ni/Au with thickness. After multi-layer metal stacking, rapid thermal annealing (RTA) process was applied with stepwise annealing temperature program profile. As results, we obtained a minimum specific contact resistance of $1.6{\times}10^{-7}{\Omega}cm2$.

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Optimization of the Power MOSFET with Fixed Device Dimensions (고정된 소자치수를 갖는 전력 MOSFET의 최적화)

  • Choi, Yearn-Ik;Hwang, Kue-Han;Park, Il-Yong
    • Proceedings of the KIEE Conference
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    • 1996.11a
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    • pp.457-461
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    • 1996
  • An optimum design methodology for the power MOSFET's with a predetermined mask is proposed and verified by comparing with the results of MEDICI simulation and the data of commercially available devices. Optimization is completed by determining a doping concentration and a thickness of the epitaxial layer which satisfy a specific voltage and current rating requirements as well as a minimum on-resistance for the mask set. The commercial HEX-1 mask set with a die area of $40.4{\times}10^{-3}\;cm^2$ and a T0-220 package has the on-resistance of $1.5{\Omega}$ at 200 V/2.5 A rating while the M-1 mask from this study exhibits $0.6{\Omega}$ on-resistance at 200 V/6 A. The 60 % reduction in the on-resistance and 58 % enhancement in the current rating have been obtained by the proposed method.

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Immune Correlates of Resistance to Trichinella spiralis Reinfection in Mice

  • Chu, Ki-Back;Kim, Sang-Soo;Lee, Su-Hwa;Lee, Dong-Hun;Kim, Ah-Ra;Quan, Fu-Shi
    • Parasites, Hosts and Diseases
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    • v.54 no.5
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    • pp.637-643
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    • 2016
  • The immune correlate of host resistance induced by reinfection of Trichinella spiralis remains unclear. In this study, we investigated immune correlates between the resistance and serum IgG antibody level, $CD23^+$ $IgM^+$ B cells, and eosinophil responses induced by T. spiralis reinfection. Mice were primarily infected with 10 or 100 T. spiralis larvae (10 TS, 100 TS), respectively, and after 4 weeks, they were challenge infected with 100 T. spiralis larvae (10-100 TS, 100-100 TS). Upon challenge infections, 10-100 TS mice induced significantly higher levels of T. spiralis-specific total IgG antibody responses in sera and antibody secreting cell responses in spleens compared to 100-100 TS mice, resulting in significantly reduced worm burdens in 10-100 TS mice (60% and 70% reductions for adult and larvae, respectively). Higher levels of eosinophils were found in mice primarily infected with 10 TS compared to those of 100 TS at week 8 upon challenge. $CD23^+$ $IgM^+$ B cells were found to be increased significantly in mice primarily infected with 10 TS. These results indicate that primary infection of 10 larvae of T. spiralis, rather than 100 larvae, induces significant resistance against reinfection which closely correlated with T. spiralis-specific IgG, eosinophil, and $CD23^+$ $IgM^+$ B cell responses.

A literature study on oncological Immune therapy (암(癌)의 면역치료(免疫治療)에 대(對)한 고찰(考察))

  • Park, Jong-Hak;Son, Chang-Gyu;Cho, Chong-kwan
    • Journal of Haehwa Medicine
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    • v.9 no.2
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    • pp.211-221
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    • 2001
  • A literature study on oncological immune therapy was done, and the results were as follows. 1. Oncological immune therapy is classified as specific non specific therapy or active inactive therapy, and in tumor immune response, cellular immunity operates mainly, so activity of T lymphocytes and macrophages are closely related with growth, progress, metastasis and prospect of tumor. Recently, Immune therapies of gene which use cytokines and HLA-B7 are carrying out. 2. In oriental medicine, development of disease is closely related to up and down of healthy qi, so healthy qi operates as a immune factor and resistance factor. 3. On the base of theory "Increasing healthy qi reduces mass(養正則積自除)", strengthening body resistance is emphasized in cancer therapy. Also strengthening body resistance activates cellular immune response and promote killing tumor facility of T-cell. 4. In clinical view, using immune therapy after operation, radiation, and chemotheraphy is more effective than immune therapy itself, so it is expected that east-west cooperation will be effective in cancer therapy. 5. The study of oncological immunity is progressed on emphasizing T-cell and it is related to oriental medical theory "strengthening healthy qi to eliminate pathogen(扶定祛邪)" and advanced study is expected in future.

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Development of molecular marker to select resistant lines and to differentiate the races related to powdery mildew in melon (Cucumis melo L.) (멜론 흰가루병의 race 분화 및 저항성 계통 선발을 위한 분자마커 개발)

  • Kim, Hoy-taek;Park, Jong-in;Ishikawa, Tomoko;Kuzuya, Maki;Horii, Manabu;Yashiro, Katsutoshi;Nou, Ill-sup
    • Journal of Plant Biotechnology
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    • v.42 no.4
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    • pp.284-289
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    • 2015
  • Powdery mildew (Podosphaera xanthii) commonly occurs in cultivated fields of melon (Cucumis melo L.). It inflicts a lot of damages. Therefore, breeding resistant lines is essential. Development of a resistant line by integrating resistance gene takes a long time. In addition, break down of developed resistance by generating new virulent fungus strains increases disease susceptibility. This phenomenon was related to races of powdery mildew. Therefore, it is important to develop a DNA marker to genetically analyze race-specific resistance genes of melon powdery mildew to breed resistant lines. To date, a total of 28 races of Podosphaera xanthii have been reported in the literature. In Japan, 10 races have been reported in the Ibaraki region. We developed a system to characterize the races of Podosphaera xanthii and confirmed eight out of those 10 races in the Ibaraki region. In Korea, only one race has been characterized to date. However, some different races were detected. Through genetic analysis of resistant lines and susceptible lines of powdery mildew, resistance genes of race1 (Pm-X, PXB, and Pm-R 1), race N1 (PXA), race 2 (Pm-w and Pm-R 2), race 3 (Pm-X3), and race 5 (Pm-X5 and Pm-R5) were identified in melon. These related genes of race 1, 3, N1, 5, and race 1, 2, 5 were located at linkage group II and V, respectively. In race 1, resistance gene was located in the linkage group XII. In addition, each race-specific marker related to specific resistance gene was developed. Using race information and race selection system obtained in this study, resistant line can be bred to develop resistant cultivar for several areas. Furthermore, this will make it more easily and economically to breed resistant lines by using selected markers.

Physical and Electrical Characteristics of Varnish and Varnish Treated Insulating Paper for Pole Transformers

  • Jung, Jong-Wook;Song, Il-Keun;Koo, Kyo-Sun;Song, Hyun-Seok;Kwak, Hee-Ro;Han, Yong-Huei
    • KIEE International Transactions on Electrophysics and Applications
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    • v.2C no.6
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    • pp.321-326
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    • 2002
  • This paper describes the mechanical and electrical characteristics of insulating paper impregnated with diluted varnish(W-128), according to Korean Standards. The varnish was diluted with a solvent of 6 different wt%. Kraft paper and Nomex paper were impregnated with the diluted varnish in a vacuum condition, and then completely dried. As the mechanical characteristics, the thickness of the completely dried varnish, the drying time and the tensile strength of the specimens were measured, and as the electrical characteristics, the permittivity, the tan $\delta$ and the specific resistance were evaluated as well.

A Study on Temperature Dependent Super-junction Power TMOSFET

  • Lho, Young Hwan
    • Journal of IKEEE
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    • v.20 no.2
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    • pp.163-166
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    • 2016
  • It is important to operate the driving circuit under the optimal condition through precisely sensing the power consumption causing the temperature made mainly by the MOSFET (metal-oxide semiconductor field-effect transistor) when a BLDC (Brushless Direct Current) motor operates. In this letter, a Super-junction (SJ) power TMOSFET (trench metal-oxide semiconductor field-effect transistor) with an ultra-low specific on-resistance of $0.96m{\Omega}{\cdot}cm^2$ under the same break down voltage of 100 V is designed by using of the SILVACO TCAD 2D device simulator, Atlas, while the specific on-resistance of the traditional power MOSFET has tens of $m{\Omega}{\cdot}cm^2$, which makes the higher power consumption. The SPICE simulation for measuring the power distribution of 25 cells for a chip is carried out, in which a unit cell is a SJ Power TMOSFET with resistor arrays. In addition, the power consumption for each unit cell of SJ Power TMOSFET, considering the number, pattern and position of bonding, is computed and the power distribution for an ANSYS model is obtained, and the SJ Power TMOSFET is designed to make the power of the chip distributed uniformly to guarantee it's reliability.

Oxidation and Electrical Properties of (LaSr)(CrCo)3Coated STS-430 Steel by Plasma Spraying (플라즈마 스프레이 (LaSr)(CrCo)O3 코팅된 STS-430 합금의 고온 산화 거동 및 전기적 특성)

  • Lee, Chung-Hwan;Lim, Kyeong-Tae;Baik, Kyeong-Ho
    • Journal of Powder Materials
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    • v.16 no.3
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    • pp.185-190
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    • 2009
  • Fe-Cr steels are the most promising candidate for interconnect in solid oxide fuel cells. In this study, an effective, dense and well adherent (LaSr)(CrCo)$O_3$ [LSCC] coating layer was produced onto 430 stainless steel (STS-430) by atmospheric plasma spraying and the oxidation behavior as well as electrical properties of the LSCC coated STS-430 were investigated. A significant oxidation of pristine STS-430 occurred at $800^{\circ}C$ in air environment, leading to the formation of $Cr_2O_3$ and $FeCr_2O_4$ scale layer up to ${\sim}7{\mu}m$ after 1200h, and consequently increased an area specific resistance of $330\;m{\Omega}{\cdot}cm^2$. Although the plasma sprayed LSCC coating contained the characteristic pore network, the coated samples presented apparent advantages in reducing oxidation growth of STS-430, resulting a decrease in oxide scale thickness of ${\sim}1{\mu}m$ at $800^{\circ}C$ after 1200h. The area specific resistance of the LSCC coated STS-430 was much reduced to ${\sim}7\;m{\Omega}{\cdot}cm^2$ after exposure at $800^{\circ}C$ for 1200h, compared to that of the pristine STS-403.