نتایج جستجو برای: dielectric constant and dielectric loss

تعداد نتایج: 16891834  

2010
Sam Wetterlin

Introduction The dielectric constant of PCB material is important in determining the trace width required to produce a characteristic impedance of 50 ohms, or any other desired impedance. The most commonly used material, FR-4, has a dielectric constant that may vary widely between manufacturers or batches, and also varies over frequency. It is useful to have a method to determine the dielectric...

2010
Wenchuan Guo Xinhua Zhu Hui Liu Rong Yue Shaojin Wang

The knowledge of dielectric properties may hold a potential to develop a new technique for quality evaluation of milk. The dielectric properties of water-diluted cow’s milk with milk concentrations from 70% to 100% stored during 36 h storage at 22 C and 144 h at 5 C were measured at room temperature for frequencies ranging from 10 to 4500 MHz using open-ended coaxial-line probe technology, alon...

Journal: :Journal of theoretical & computational chemistry 2014
Lin Li Chuan Li Emil Alexov

Traditional implicit methods for modeling electrostatics in biomolecules use a two-dielectric approach: a biomolecule is assigned low dielectric constant while the water phase is considered as a high dielectric constant medium. However, such an approach treats the biomolecule-water interface as a sharp dielectric border between two homogeneous dielectric media and does not account for inhomogen...

Journal: :journal of the iranian chemical research 0
beena bhaskaran department of chemistry, d. b college, sasthamcotta, kollam, kerala, india manoj sadanandan, department of chemistry, d. b college, sasthamcotta, kollam, kerala, india

nanoparticles of zirconium(iv) tungstate are prepared by chemical co-precipitation method. thecharacterizations have been carried out by tg/dta, dsc, afm, xrd, ftir and uv-vis spectrum. plspectrum shows two emission bands at 350 nm and at 477 nm. the effects of frequency on the dielectricbehavior and ac electrical conductivity have been studied. the dielectric constant is found to be 119.43 at1...

2001
H. LANGHALS

Materials with high dielectric constants find wide application in electronic devices, for instance in capacitors, wave guides, and reflective materials for electromagnetic radiation. For very high dielectric constants materials with ion or dipole lattices are usually used, for example the dielectrics in tantalum capacitors. However, these materials have the disadvantage of a rather strong coupl...

1997
ALVIN L.S. LOKE JEFFREY T. WETZEL JOHN J. STANKUS SIMON WONG

Fluorinated polyimide can potentially replace TEOS as an interlevel dielectric in future ULSI interconnect technologies because its lower dielectric constant offers reduced crosstalk, signal propagation delay, and dynamic power dissipation. One issue associated with polyimides is the anisotropy in dielectric constant, where the smaller out-of-plane dielectric constant, typically measured using ...

2011
Patcharee Intanoo Anuvat Sirivat Ruksapong Kunanuruksapong Wanchai Lerdwijitjarud

Ethylene propylene diene elastomers (EPDM) of various side chains and molecular weights were prepared as thin discs and the effects of electric field strength and temperature on the electromechanical properties were investigated. The electrical conductivity, the dielectric constant, the storage and loss moduli (G and G), the storage modulus response ( 1000V mm G  ), and the storage modulus ...

2002
Helene E. de Bruijn Jan Greve

We derive a method for the determination of the dielectric constant and thickness of a thin dielectric layer, deposited on top of a thick dielectric layer which is in turn present on a metal film. Reflection of pand s-polarlzed light from the metal layer yields minima for certain angles of incidence where the light is absorbed by the metal. The thin dielectric layer causes shifts in the angles ...

2013
Lin Li Chuan Li Zhe Zhang Emil Alexov

Implicit methods for modeling protein electrostatics require dielectric properties of the system to be known, in particular, the value of the dielectric constant of protein. While numerous values of the internal protein dielectric constant were reported in the literature, still there is no consensus of what the optimal value is. Perhaps this is due to the fact that the protein dielectric consta...

2016
Binke Huang Qi Jia

This paper details an effective method to extract dielectric parameters including dielectric constant Dk and loss tangent Df from transmission lines containing rough conductor surface. The concept of effective conductivity is firstly introduced to model conductor surface roughness in transmission lines. By using differential extrapolation method, propagation parameters of transmission lines can...

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