Anomalous Thermal Behavior of CuxMg1-xNb2O6 (x=0,0.4,0.6,1) for LTCC Substrate
LTCC (Low Temperature Co-fired Ceramics) being the most advantageous technology towards the multilayer substrates for various applications, demands an extensive study of its raw materials. In the present work, a series of CuxMg1-xNb2O6 (x=0,0.4,0.6,1) has been prepared using sol-gel synthesis route and sintered at a temperature of 900°C to study its applicability for LTCC technology as the firing temperature is 900°C in this technology. The phase formation has been confirmed using X-ray Diffraction. Thermal properties like thermal conductivity and thermal expansion being very important aspect as the former defines the heat flow to avoid thermal instability in layers and the later provides the dimensional congruency of the dielectric material and the conductors, are studied here over high temperature up to the firing temperature. Although the values are quite satisfactory from substrate requirement point view, results have shown anomaly over temperature. The anomalous thermal behavior has been further analyzed using TGDTA. Keywords—Niobates, LTCC, Thermal conductivity, Thermal expansion, TG-DTA.
Preparation of CuNb2O6 nanocrystalline powders by sol–gel method
Abstract The soluble solution with Nb 5+ was obtained by dissolving Nb 2 O 5 into HF acid, and CuNb 2 O 6 nanocrystalline powders were synthesized using this soluble solution as starting materials at a low temperature by sol–gel method in this study. The crystal structure and microstructure of CuNb 2 O 6 powders were characterized by XRD and SEM techniques, and the effects of pH value and the molar ratio of citric acid to the niobium ions (CA/Nb) on the crystal structure and microstructure of CuNb 2 O 6 powders were also investigated. XRD and TG/DTA results show that the monoclinic phase of CuNb 2 O 6 for synthesized powders can be obtained by calcining the precursor at 600 °C. The average particle size of CuNb 2 O 6 ranges from 20 nm to 85 nm with varying the CA/Nb and pH values, and 20 nm of the particle size can be obtained for the CuNb 2 O 6 powders by heating the precursor at 600 °C for 2 h.
On the ontology of particle mass and energy in special relativity
Einstein claimed that the fundamental dynamical insight of special relativity was the equivalence of mass and energy. I disagree. Not only are mass and energy not equivalent (whatever exactly that means) but talk of such equivalence obscures the real dynamical insight of special relativity, which concerns the nature of 4-forces and interactions more generally. In this paper I present and defend a new ontology of special relativistic particle dynamics that makes this insight perspicuous and I explain how alleged cases of mass–energy conversion can be accommodated within that ontology.