EFFECT OF PREPARATION CONDITION ON THERMAL EXPANSION ANISOTROPY FOR AMORPHOUS Fe_(78)B_(13)Si_9 ALLOY

The thermal expansion along the longitudinal and transverse directions for amorphous Fe_(78)B_(13)Si_9 alloy prepared under various preparing conditions were investigated.The thermal expansion anisotropy appears in all specimens.The expansion along the longitudinal direction is less than that along the transverse direction.The cooling rate,the melt temperature before jet casting and the cycling temperature affect the thermal expansion coefficients and anisotropy.The amisotropy of thermal expansion originates from the orientation of atomic interaction force,the atomic oscillatory frequency and short range order structure or the directional arrangement of defects in the alloy.

Thermostable Broad Band Polarizing PVA-Film: Theoretical and Experimental Investigations

In the present work, for the first time on the basis ofpoly （vinyl alcohol） （PVA）, 2- （4-dimethylaminostyryl）-l-ethylquinolinium iodide （quinaldine red （QR）） and trisodium （4E）-5-oxo- 1-（4-sulfonatophenyl）-4-[（4-sulfonatophenyl）hydrazono]-3 pyrazolecarboxylate （tartrazine （T））, thermostable polarizing film in a wide range of spectra （λmax=394-511 nm） with polarization efficiency （PE） = 98% in absorption maximum and stretching degree （Rs） = 3.5 was developed. The basic spectral-polarization parameters （polarization efficiency and transmittance） of oriented colored PVA-films were measured and discussed. During the work it was found that oriented PVA-films are the phenomenon of anisotropy of thermal conductivity （λ｜/λ⊥）. It is a very important parameter for the development of thermostable PVA-polarizing films. For the first time quantum-chemical calculations using density functional theory （DFT） approach for structural analysis and electronic spectrum of the QR were carried out via the B3LYP/dgdzvp and TDB3LYP/dgdzvp methods. Interpretation of absorption strips in visible region of spectrum was also reported. The excitation energies, electronic transitions and oscillator strengths for the studied structures have also been calculated （B3LYP/dgdzvp）. The NBO analysis and Mulliken atomic charges of the QR were carried out.

Tailoring thermal conductivity of bulk graphene oxide by tuning the oxidation degree

Bulk graphene oxide （GO） shows great potential in a variety of applications, such as sensors,photodetectors, supercapacitors, lithium ion batteries and catalysts. However, its thermal conductivity,one of the most important and fundamental physical properties, is still less known. Herein, we havesystematically investigated the thermal conductivity of bulk GOs and find that it can be tailored by tuningtheir oxidation degree during preparation process. Notably, the cross-plane thermal conductivity of bulkGO, in comparison with its precursor graphite, exhibits more than 100 times decrease at roomtemperature. The dependence of thermal conductivity of GO on oxidation degree is attributed to thechemical and structural changes by introducing oxygen atoms and oxygen-containing functional groups,which can lead to a significant enhancement in atomic- and nano-scale phonon scattering. Furthermore,we reveal that the thermal conductivity of bulk GOs exhibits evident anisotropic behavior. These resultsprovide fundamental understanding and valuable information on thermal transport properties of bulkGOs for various practical applications.