نتایج جستجو برای: ultra high temperature ceramics uhtcs

تعداد نتایج: 2425766  

2005
Harald Schmidt

1. Introduction Using solid state thermolysis of pre-ceramic polymers, it is possible to produce amorphous Si-(B-)C-N ceramics which are a new form of a glassy-like state with an enormous stability range up to 1700 °C (see e. g. [1,2]). Si-(B-)C-N ceramics are promising candidates for the design of ultra-high temperature stable structure materials. The thermal stability and the crystallization ...

2004
G. P. Kothiyal

Glasses and glass-ceramics (GCs) used for sealing, coating and high voltage applications belong to a special class of materials in which among other requirements, matching of thermal expansion coefficient with that of metal as closely as possible up to set temperature is an important consideration. In this paper I shall concentrate on some indigenous efforts carried out in my laboratory on the ...

2015
Elisa Sani Marco Meucci Luca Mercatelli David Jafrancesco Jean-Louis Sans Laura Silvestroni Diletta Sciti

It is a known rule that the efficiency of thermodynamic solar plants increases with the working temperature. At present the main limit in temperature upscaling is the absorber capability to withstand high temperatures. The ideal solar absorber works at high temperatures and has both a low thermal emissivity and a high absorptivity in the solar spectral range. The present work reports on the pre...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1390

in this thesis, a better reaction conditions for the synthesis of spirobarbiturates catalyzed by task-specific ionic liquid (2-hydroxy-n-(2-hydroxyethyl)-n,n-dimethylethanaminium formate), calcium hypochlorite ca(ocl)2 or n-bromosuccinimide (nbs) in the presence of water at room temperature by ultrasonic technique is provided. the design and synthesis of spirocycles is a challenging task becaus...

2015
Liang Wang Yang Bai Xuefei Lu Jiang-Li Cao Li-Jie Qiao

High permeability and high permittivity are hard to be achieved simultaneously, either in single-phased materials or in composite materials, such as ferrite-ferroelectric ceramic composites and ferrite-metal percolative composites. In this work, ultra-low percolation threshold is achieved in NiZnCu ferrite-Ag cofired ceramics, which endows the composite with both high permeability and high perm...

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