Novel Emitter-Segmented Power HBT with 2-D Non-Uniform Segment Spacing for High Thermal Stability

2013 ◽  
Vol 313-314 ◽  
pp. 737-741
Author(s):  
D.Y. Jin ◽  
R.X. Hu ◽  
W.R. Zhang ◽  
D. Lu ◽  
Q. Fu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Effects ◽  
Thermal Model ◽  
Power Level ◽  
High Thermal Stability ◽  
Thermal Coupling ◽  
Resistance Matrix ◽  
Coupling Resistance ◽  
Lower Temperature ◽  
Thermal Stability Of

With the aid of the thermal model, thermal resistance matrix of emitter-segmented power HBT is proposed to represent thermal effects. The effect of 2-dimensional (2-D) inter-segment spacing on thermal stability of device is studied. It is shown that the increase of inter-segment spacing could effectively decrease thermal coupling resistance, lower temperature of center segments, and hence improves the thermal stability. Furthermore, a novel emitter-segmented power HBT with 2-D non-uniform segment spacing is proposed, in which the non-uniformity of segment temperature is improved by 75.26% and the maximum power level difference of emitter segment is improved by 55.84%, when compared with uniform segment spacing HBT. Therefore the technique of 2-D non-uniform segment spacing is a better method for enhancing the thermal stability of power HBTs.

Porous homo- and heterochiral cobalt(II) aspartates with high thermal stability of the metal-organic framework

2010 ◽  
Vol 59 (4) ◽  
pp. 733-740 ◽  
Author(s):  
M. P. Yutkin ◽  
M. S. Zavakhina ◽  
D. G. Samsonenko ◽  
D. N. Dybtsev ◽  
V. P. Fedin
Keyword(s):  
Thermal Stability ◽  
Metal Organic Framework ◽  
High Thermal Stability ◽  
Metal Organic ◽  
Thermal Stability Of ◽  
Organic Framework

High thermal stability of the YNbO4 − CaYTiNbO7 composites for radio frequency and microwave applications

2021 ◽  
pp. 124956
Author(s):  
F.F. do Carmo ◽  
J.P.C. do Nascimento ◽  
J.E.V. de Morais ◽  
V.C. Martins ◽  
J.C. Sales ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Radio Frequency ◽  
High Thermal Stability ◽  
Microwave Applications ◽  
Thermal Stability Of

Thermal Stability of 40Cr Steel with Surface Nanocrystallization

2006 ◽  
Vol 510-511 ◽  
pp. 434-437 ◽  
Author(s):  
Yu Liang Liu ◽  
Tian Ying Xiong ◽  
Ke Yang
Keyword(s):  
Thermal Stability ◽  
Surface Layer ◽  
Nanostructured Materials ◽  
High Thermal Stability ◽  
New Method ◽  
Nanostructured Surface ◽  
Surface Nanocrystallization ◽  
Nanostructured Layer ◽  
40Cr Steel ◽  
Thermal Stability Of

Surface Nanocrystallization(SNC) is a new method of fabricating nanostructured materials while thermal stability is an important problem for the application of nanostructured materials. A nanostructured layer was fabricated on the surface of 40Cr steel by Supersonic Particles Bombarding method, and the variation of microstructure and microhardness of nanostructured layer was studied. Nanostructured surface layer showed high thermal stability.

scholarly journals Investigation of reactively sputtered TaN thin-film resistors for microwave photonic applications

2021 ◽  
pp. 93-98
Author(s):  
Evgenii Erofeev ◽  
Egor Polyntsev ◽  
Sergei Ishutkin
Keyword(s):  
Thin Film ◽  
Thermal Stability ◽  
Magnetron Sputtering ◽  
Electrical Resistance ◽  
High Thermal Stability ◽  
Tantalum Nitride ◽  
Reactive Magnetron ◽  
Microwave Photonic ◽  
Thin Film Resistors ◽  
Thermal Stability Of

Electrophysical characteristics and their thermal stability of thin-film resistors based on tantalum nitride (TaN) obtained by reactive magnetron sputtering were investigated. The optimal modes of the magnetron sputtering process are determined, ensuring the Ta2N phase film composition with the value of the specific electrical resistance of 250 μm cm and high thermal stability of the parameters. On the basis of the investigations carried out, thin-film matching resistors were manufactured for use as part of an electro-optical InP-based MZ modulator

Achieving high thermal stability of different rare-earth ions in a single matrix host via the manipulation of the local structure by a solid solution

2020 ◽  
Vol 22 (28) ◽  
pp. 16294-16300
Author(s):  
Xiuxia Yang ◽  
Lei Zhao ◽  
Zhichao Liu ◽  
Shuyu Tian ◽  
Hao Zhang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Solid Solution ◽  
Rare Earth ◽  
Local Structure ◽  
Local Environment ◽  
High Thermal Stability ◽  
Rare Earth Ions ◽  
Single Matrix ◽  
Thermal Stability Of

Manipulating the local environment of CAS by substitution of Al3+–Y3+ for Si4+–Ca2+ to achieve more stability in the structure of CYA.

Synthesis and thermal stability of dimethyl adamantanes as high-density and high-thermal-stability fuels

Fuel ◽  
2020 ◽  
Vol 260 ◽  
pp. 116424 ◽  
Author(s):  
Jiawei Xie ◽  
Tinghao Jia ◽  
Si Gong ◽  
Ning Liu ◽  
Genkuo Nie ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Thermal Stability ◽  
High Density ◽  
Thermal Stability Of

scholarly journals Case Study about the Energy Absorption Capacity of Metal Oxide Varistors with Thermal Coupling

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 536 ◽  
Author(s):  
Flaviu Frigura-Iliasa ◽  
Sorin Musuroi ◽  
Ciprian Sorandaru ◽  
Doru Vatau
Keyword(s):  
Thermal Stability ◽  
Metal Oxide ◽  
Thermal Activation ◽  
Absorption Capacity ◽  
Technical Solution ◽  
Thermal Coupling ◽  
Thermal Exchange ◽  
Surge Arresters ◽  
Thermal Stability Of

Metal oxide varistors are applied today inside modern surge arresters for overvoltage protection for all voltage levels. Their main issue is the thermal activation of their crossing current, which could lead to complete destruction by thermal runaway. This article presents a new technological solution developed in order to increase the thermal stability of metal oxide varistors. It consists in connecting in parallel two or more similar varistors (for dividing their current), having a thermal coupling between them (for equalizing their temperatures and forcing them to act together and simultaneously as much as possible). Starting from a finite element computer model performed for each situation (varistor standalone or parallel), up to real measurements, the thermal stability of the equipment was analyzed in permanent and impulse regime. Experiments were carried out in the same conditions. Experimental data obtain from two disk varistors corresponds very well to simulations, proving that parallel connection of varistors, combined with a thermal exchange between them is an efficient technical solution for thermal stability improvement, even if not apparently economically justified.

scholarly journals Synthesis of Self-colored Thermal Stabilized Acrylonitrile/Itaconic Copolymers

2019 ◽  
Vol 35 (2) ◽  
pp. 785-791
Author(s):  
AZZA ABDULLAH Al-GHAMDI
Keyword(s):  
Thermal Stability ◽  
Metal Complexes ◽  
Itaconic Acid ◽  
Ammonium Hydroxide ◽  
High Thermal Stability ◽  
Potassium Persulfate ◽  
Ammonium Hydroxide Solution ◽  
Thermal Stability Of ◽  
Thermal Stable ◽  
Oligomerization Reaction

Acrylonitrile (AN) was copolymerized with itaconic acid metal complexes [Co(II),Ni(II),Cu(II)] aiming to synthetize self-colored acrylonitrile fiber. The copolymerization occurred in water at 60°C using sodium bisulfite and potassium persulfate as redox initiators. The resulting copolymers are colored and exhibited high thermal stability as shown from their TGA curves. The investigated copolymers exhibited comparable thermal stability as that of PAN. The AN/ itaconic acid Co(NO3)2copolymer was considerably the most thermal stable copolymer while that of Ni(II) copolymer was the less stable one. Cu(II) copolymer showed an intermediate stability. The data also revealed that the maximum degradation occurred after 300°C (the cyclization temperature). Thus, neither the copolymerization nor the complexation affected the nitrile oligomerization reaction. The effect of adding ammonium hydroxide solution to acrylonitrile – itaconic acid copper(II) complex copolymer on the thermal stability of copolymer was also studied.

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