• 한국세라믹학회지
• /
• 제27권3호
• /
• pp.337-344
• /
• 1990

As a function of sintering temperature and time, the electrical properties of ruthenium based thick film resistors were investigated with microstructure. The variatio of resistivity and TCR(temperature coefficient of resistance)trends of sintered speciman at various sintering temperature were different low resistivity paste(Du Pont 1721) from high one(Du Pont 1741). These phenomena are deeply relative to microstructure of sintered film. With increasing the sintering temperature for 1721 system, the electrical sheet resistivity decreased, but again gradually increased above 80$0^{\circ}C$. And TCR trends in 1721 system are all positive. On the other hand the electrical sheet resistivity of 1741 resistor system decreased with sintering temperature. And TCR trends variable according to sintering temperature. TCR of speciman sintered at $700^{\circ}C$ was negative value, and TCR of 80$0^{\circ}C$ sintered speciman coexisted negative and positive value. But in case of speciman sintered at 90$0^{\circ}C$, TCR was positive value. As results of this fact, it was well known that the charge carrier contributied to electrical conduction in 1741 resistor system varied with sintering temperature.

• BMB Reports
• /
• 제38권3호
• /
• pp.334-342
• /
• 2005

Recently, the existence of T cells with dual T cell receptor (TCR) in the immune system is generally accepted, while it has been controversial whether signals through one TCR would affect the functions of the other. In this study T cells expressing two different TCR were obtained from cross-hybrids of LCMV and AND TCR transgenic mice specific for the gp33 and peptide fragment of PCC (fPCC), respectively. Peptide stimulation demonstrated that the dual TCR T cells functioned independently in an antigen-specific manner. To examine whether the tolerance targeted for the one TCR affects the responsiveness of the other, the cross-hybrids were treated with gp33. Although T cells from F1 mice were rendered anergenic to gp33, no functional changes to fPCC were observed in terms of cellular proliferation and IL-2 secretion, suggesting that the dual TCR T cells remained reactive to fPCC. We therefore propose that signaling through the TCR is receptor-specific and 'negative dominance' of one TCR by tolerance induction is not applicable in this dual TCR system.

• 한국재료학회지
• /
• 제2권1호
• /
• pp.58-64
• /
• 1992

$\textrm{RuO}_2$와 glass의 비가 20/80과 12/88인 두종류의 후막저항계에 NTCR 특성을 나타내는 여러종류의 산화물을 첨가하였을때 저항체의 TCR과 전기비저항이 어떻게 변화하는가에 대한 실험을 실시하였다. 첨가된 TCR modifier들이 NTCR특성을 갖는다고해서 저항체의 TCR이 창상 감소되지는 않으며 또한 어떠한 modifier가 모든 저항계에 항상 일정 방향으로만 TCR을 변화시키지는 않았다. 그러나 이들 TCR modifier들을 적당량 첨가함으로써 후막저항체의 TCR과 저항값을 원하는 바대로 얻을 수 있다는 가능성을 확인하였다. 두 종류의 이상의 TCR modifier를 동시에 첨가하였을때에 첨가된 TCR modifier들 각각의 TCR변화가 합해져서 결과로 나타남으로써 이들 사용된 TCR modifier들 간에는 상호작용이 없음을 알 수 있었다. TCR modifier의 첨가량은 2~3%내로 억제하는 것이 바람직함을 알 수 있었다.

• 한국전기전자재료학회논문지
• /
• 제32권3호
• /
• pp.219-222
• /
• 2019

In this study, we fabricated plate-type shunt resistors with thermal stability by parallelly connecting metal alloy plates with positive temperature coefficient of resistance (TCR) and carbon nanotube (CNT) plates with negative TCR. The metal alloy plates, which were prepared by alloying Cu and Mn with a composition of 91 wt% of Cu and 9 wt% of Mn, showed around $800ppm/^{\circ}C$ of TCR, and the CNT plates prepared from the CNT solution by using the vacuum filtration method showed around $-800ppm/^{\circ}C$ of TCR. The shunt resistor that was fabricated by stacking metal alloy plates and CNT plates in this work showed about $46.93ppm/^{\circ}C$ of TCR. Therefore, we conclude that a shunt resistor with low TCR can be realized by simply adjusting the TCR of the metal alloy only, because the TCR of the CNT plate has an identical value.

• IMMUNE NETWORK
• /
• 제11권6호
• /
• pp.336-341
• /
• 2011

T cell receptor (TCR) signaling plays a critical role in T cell development, survival and differentiation. In the thymus, quantitative and/or qualitative differences in TCR signaling determine the fate of developing thymocytes and lead to positive and negative selection. Recently, it has been suggested that self-reactive T cells, escape from negative selection, should be suppressed in the periphery by regulatory T cells (Tregs) expressing Foxp3 transcription factor. Foxp3 is a master factor that is critical for not only development and survival but also suppressive activity of Treg. However, signals that determine Treg fate are not completely understood. The availability of mutant mice which harbor mutations in TCR signaling mediators will certainly allow to delineate signaling events that control intrathymic (natural) Treg (nTreg) development. Thus, we summarize the recent progress on the role of TCR signaling cascade components in nTreg development from the studies with murine model.

• 한국전기전자재료학회논문지
• /
• 제30권1호
• /
• pp.59-62
• /
• 2017

CNT (carbon nanotube) resistors with low resistance and negative TCR (temperature coefficient of resistance) were fabricated with yarned CNT (carbon nanotube) fibers. The CNT fibers were prepared by yarning CNTs grown on the silicone substrate by CVD (chemical vapor deposition) method. The CNT resistors were fabricated by winding CNT fibers on the surface of ceramic rod. Both metal terminals were connected with the CNT fiber wound on the ceramic rod. We measured electrical resistance and thermal stability with the number of CNT fibers wound. The CNT resistor system shows linearly decreased resistance with the number of CNTs wound on the ceramic rod and saturated at 20 strands. The CNT resistor system has negative TCR between $-1,000{\sim}-2,000ppm/^{\circ}C$ and stable frequency properties under 100 kHz.

• 한국전기전자재료학회논문지
• /
• 제37권3호
• /
• pp.323-327
• /
• 2024

The low-temperature coefficient of resistance (TCR) is a crucial factor in the development of space-grade resistors for temperature stability. Consequently, extensive research is underway to achieve zero TCR. In this study, resistors were deposited by co-sputtering nickel-chromium-based composite compositions, metals showing positive TCR, with SiO₂, introducing negative TCR components. It was observed that achieving zero TCR is feasible by adjusting the proportion of negative TCR components in the deposited thin film resistors within certain compositions. Additionally, the correlation between TCR and deposition conditions, such as sputtering power, Ar pressure, and surface roughness, was investigated. We anticipate that these findings will contribute to the study of resistors with very low TCR, thereby enhancing the reliability of space-level resistors operating under high temperatures.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 B
• /
• pp.1094-1097
• /
• 2001

The control method of Thyristor-controlled Reactor(TCR) is described in this paper for compensating the poor power factor, unbalanced and/or nonlinear load. Also, auxiliary controller such as DC current and power-factor controller is described. The reference current of TCR is calculated from the active and reactive current components for each of the positive and negative sequence components in the load currents. This reactive power control technique was verified by Matlab Simulink and 33Kvar TCR simulator, and will be used in 4.3Mvar TCR system, which will be installed next year at R-Tech Co., located in Po-Hang.

• 대한전기학회논문지:전력기술부문A
• /
• 제52권10호
• /
• pp.577-583
• /
• 2003

The control method of Thyristor Controlled Reactor(TCR) is described in this paper for compensating the poor power factor, unbalanced and/or nonlinear load. Also, auxiliary controller such as DC current and power-factor controller is described. The reference current of TCR is calculated from the active and reactive Current components for each of the positive and negative sequence components in the load Currents. This reactive power control technique was verified by simulation program and will be used in 5Mvar TCR system, which will be installed next year at hot rolled mill at POSCO, located in Kwang-Yang.

• IMMUNE NETWORK
• /
• 제4권2호
• /
• pp.81-87
• /
• 2004

Background: In the thymus, developing thymocytes continually interact with thymic epithelial cell components. Self MHC restriction of mature T cells are imposed in the thymus through interaction of immature double positive thymocytes and thymic cortical epithelial cells. The site of negative selection, however, is a matter of debate. Through systemic injection of anti-TCR antibody or antigenic peptides, investigators suggested that most of the negative selection occurs in the thymic cortex. But the requirements for negative selection, i.e cellular counterparts and costimulatory molecules are more available in the medulla or cortico-medullary junction rather than in the thymic cortex. Methods: The direct and indirect pathways of thymocyte death after systemic anti-TCR antibody injection were separated through several experimental systems. B6 mice were either adrenalectomized or sham-adrenalectomized to evaluate the role of endogenous glucocorticoids from adrenal gland. Role of TNF were evaluated through using TNF receptor double knockout mice. Results: We found that without indirectly acting mediators such as $TNF-\alpha$ or corticosteroid, double positive thymocyte death were minimal by systemic injection of anti-TCR antibody in TNF receptor double knockout neonatal mice. Also by analyzing neonatal wild-type mice with adoptively transferred mature T cells, only peripheral activation of mature T cells could induce extensive double positive thymocyte death. Conclusion: Thus, systemically injected anti-TCR antibody mediated thymocyte death are mostly induced through indirect pathway.