Preparation and characterization of protein/viscose fiber and its action in self-heating

A new flame-retardant protein viscose fiber with safely wearing performance has been prepared through blending protein solution, flame retardant (hexaphenoxycyclotriphosphazene) and viscose spinning solution, in which wool protein was used and added to spinning solution on the basis of 16% flame retardant, and the properties of the fiber were investigated. The product has more compact structure inside the fiber and evenly scattered small pores on the surface. Flame-retardant protein viscose fiber can reach the flame-retardant standard both before and after 30 times wash test, and the mechanical strength of the fiber was also improved. The introduction of hexaphenoxycyclotriphosphazene lowered the primary decomposition temperature of viscose fiber, reduced its weight loss. The flame-retardancy of the fiber can be improved by the introduction of protein. In thermal processes, the major product of thermal decomposition was CO2, no hazardous and noxious gases were released. Due to the introduction of protein, moisture regain of the fiber is a little lower than that of viscose fiber, but higher than flame-retardant viscose fiber. Warmth retention property was also improved. Friction coefficient of the product is lower than that of flame-retardant viscose fiber. Bulking intensity was increased, which is better than that of viscose fiber.

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Characterization of self-heating in GaN high electron mobility transistors using channel resistance measurement

Japanese Journal of Applied Physics ◽

10.7567/1347-4065/ab07a2 ◽

2019 ◽

Vol 58 (SC) ◽

pp. SCCB11 ◽

Cited By ~ 1

Author(s):

Mei Wu ◽

Meng Zhang ◽

Qing Zhu ◽

Ling Yang ◽

Xiaohua Ma ◽

...

Keyword(s):

Electron Mobility ◽

High Electron Mobility Transistors ◽

Resistance Measurement ◽

High Electron ◽

High Electron Mobility ◽

Self Heating ◽

Electron Mobility Transistors ◽

Channel Resistance

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Thermal Characterization of Cu/CoFe Multilayer for Giant Magnetoresistive (GMR) Head Applications

Heat Transfer, Volume 2 ◽

10.1115/imece2004-62113 ◽

2004 ◽

Cited By ~ 1

Author(s):

Y. Yang ◽

M. Asheghi

Keyword(s):

Giant Magnetoresistance ◽

Room Temperature ◽

Boltzmann Transport Equation ◽

Thermal Characterization ◽

Disk Drive ◽

Boltzmann Transport ◽

Self Heating ◽

Superlattice Structure ◽

Metallic Ferromagnet

Giant Magnetoresistance (GMR) head technology is one of the latest advancement in hard disk drive (HDD) storage industry. The GMR head superlattice structure consists of alternating layers of extremely thin metallic ferromagnet and paramagnet films. A large decrease in the resistivity from antiparallel to parallel alignment of the film magnetizations can be observed, known as giant magnetoresistance (GMR) effect. The present work characterizes the in-plane electrical and thermal conductivities of Cu/CoFe GMR multilayer structure in the temperature range of 50 K to 340 K using Joule-heating and electrical resistance thermometry in suspended bridges. The thermal conductivity of the GMR layer monotonously increased from 25 Wm−1K−1 (at 55 K) to nearly 50 Wm−1K−1 (at room temperature). We also report the GMR ratio of 17% and a large negative magnetothermal resistance effect (GMTR) of 33% in Cu/CoFe superlattice structure. The Boltzmann transport equation (BTE) is used to estimate the GMR ratio, and to investigate the effect of repeats, as well as the spin-dependent interface and boundary scatting on the transport properties of the GMR structure. Aside from the interesting underlying physics, these data can be used in the predictions of the Electrostatic Discharge (ESD) failure and self-heating in GMR heads.

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Characterization of Self-Heating Process in GaN-Based HEMTs

Electronics ◽

10.3390/electronics9081305 ◽

2020 ◽

Vol 9 (8) ◽

pp. 1305 ◽

Cited By ~ 1

Author(s):

Daniel Gryglewski ◽

Wojciech Wojtasiak ◽

Eliana Kamińska ◽

Anna Piotrowska

Keyword(s):

Communication Systems ◽

Accurate Determination ◽

Heating Process ◽

Equivalent Circuits ◽

High Electron ◽

Thermal Impedance ◽

Self Heating ◽

Gan Hemt

Thermal characterization of modern microwave power transistors such as high electron-mobility transistors based on gallium nitride (GaN-based HEMTs) is a critical challenge for the development of high-performance new generation wireless communication systems (LTE-A, 5G) and advanced radars (active electronically scanned array (AESA)). This is especially true for systems operating with variable-envelope signals where accurate determination of self-heating effects resulting from strong- and fast-changing power dissipated inside transistor is crucial. In this work, we have developed an advanced measurement system based on DeltaVGS method with implemented software enabling accurate determination of device channel temperature and thermal resistance. The methodology accounts for MIL-STD-750-3 standard but takes into account appropriate specific bias and timing conditions. Three types of GaN-based HEMTs were taken into consideration, namely commercially available GaN-on-SiC (CGH27015F and TGF2023-2-01) and GaN-on-Si (NPT2022) devices, as well as model GaN-on-GaN HEMT (T8). Their characteristics of thermal impedance, thermal time constants and thermal equivalent circuits were presented. Knowledge of thermal equivalent circuits and electro–thermal models can lead to improved design of GaN HEMT high-power amplifiers with account of instantaneous temperature variations for systems using variable-envelope signals. It can also expand their range of application.

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