Anvar A. Zakhidov

Bio: Anvar A. Zakhidov is an academic researcher from University of Texas at Dallas. The author has contributed to research in topics: Perovskite (structure) & Carbon nanotube. The author has an hindex of 63, co-authored 417 publications receiving 27644 citations. Previous affiliations of Anvar A. Zakhidov include University of Texas System & Business International Corporation.

Structure and nanocrystallites of Ni and NiO three dimensional ordered macromeshes

Abstract: : Three dimensional Ni and NiO inverse opal macromeshes were characterized by scanning electron microscope (SEM) and transmission electron microscope (SEM). The octahedral cubes of the macroporous Ni were found mostly grown as single crystals with staking faults and microtwins. There was no preferential growth of these cubes as determined by selected area diffraction pattern (SADP). Some NiO nanocrystals with size of about 5 nm were formed on the surface of inverse Ni opal membrane during etching away of silica spheres. The oxidation of Ni mesh turned it into NiO macromesh with grain size of about 20 nm at 550 deg C. The nanocrystalline NiO mesh is suitable for further fabrication of three dimensional nanobeads. By annealing the meshes at 650 deg C, the NiO nanograins grew to a size of over 50 nm. This three dimensional ordered macroporous structure with higher temperature treatment is considered as stable and important for further application.

Quantum model of phonon transport and heat conductivity in carbon nanoclusters and nanotubes

Abstract: A complex approach phonon quantum discrete model (PQDM) was developed to describe dynamics, kinetics and statistics of phonons in carbon nanostructures with zero-chirality of both zig-zag and armchair geometry. The model allows include into the pure phonon problem existing interaction with others subsystems: electrons, photons, impurities and defects. We predict that planar C- structures are geometrically stable and may bridge interelectrode space in strong external electric field. The exact solution of generalized thermal conductivity (TC) equation was obtained for nanotubes. Temperature distribution along the tube was derived analytically. The diagonalization procedure for the case ofstrong ph-ph interaction was proposed. It was shown the quadratic increasing of heat conductivity with the growth of the phonon mean free path (PMFP). Heat capacitance and the entropy of carbon linear tubes were calculated as the function of temperature. Our theoretical approach explains the nature of good TC in carbon and carbon-like materials by existing of the soft vibration branch (low frequency radial breathing mode phonons with high density of states at thermal energies) accompanied by structure hardness (high frequency $\phi$- and z-branches) providing big PMFP. TC coefficient for high conducting channel in surrounding medium was calculated. The mechanism of heat conductivity temperature damping was analyzed. Two competitive tendencies produce TC maximum at intermediate temperatures (100-300)K. It was shown the strongly non-linear increasing of effective heat conductivity with the growth nanotubes concentration. It was shown that insertion of armchair nanotube inside a medium or its coating by polyacetilene molecule considerably changes the structure of radial breathing phonons.

Optical sensors using materials with unusual mechanical properties or photonic bandgaps

Abstract: We describe here optical sensors whose performance depends on materials having quite unusual mechanical properties. These properties include negative Poisson's ratios and negative linear compressibilities (meaning that expansion occurs in one or more directions when the material is hydrostatically compressed). Because of the symmetry of the elastic constant compliance matrix (Sij=Sji), a material that has a negative linear compressibility must also increase density when stretched in an appropriate direction. Such a material is here referred to as a stretch-densified, which is a distinctly different property than having a negative Poisson's ratio. We will show that both the stretch-densification property (negative linear compressibility) and negative Poisson's ratios can be used to obtain dramatic enhancements in sensitivity.

Structure and Nanocrystallites of Ni and NiO Three Dimensional Ordered Macromeshes

Abstract: Three dimensional Ni and NiO inverse opal macromeshes were characterized by scanning electron microscope (SEM) and transmission electron microscope (SEM). The octahedral cubes of the macroporous Ni were found mostly grown as single crystals with staking faults and microtwins. There was no preferential growth of these cubes as determined by selected area diffraction pattern (SADP). Some NiO nanocrystals with size of about 5 nm were formed on the surface of inverse Ni opal membrane during etching away of silica spheres. The oxidation of Ni mesh turned it into NiO macromesh with grain size of about 20 nm at 550°C. The nanocrystalline NiO mesh is suitable for further fabrication of three dimensional nanobeads. By annealing the meshes at 650°C, the NiO nanograins grew to a size of over 50 nm. This three dimensional ordered macroporous structure with higher temperature treatment is considered as stable and important for further application.

Electric Field Effect in Atomically Thin Carbon Films

Abstract: We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10 13 per square centimeter and with room-temperature mobilities of ∼10,000 square centimeters per volt-second can be induced by applying gate voltage.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Carbon Nanotubes--the Route Toward Applications

Abstract: Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites; energy storage and energy conversion devices; sensors; field emission displays and radiation sources; hydrogen storage media; and nanometer-sized semiconductor devices, probes, and interconnects. Some of these applications are now realized in products. Others are demonstrated in early to advanced devices, and one, hydrogen storage, is clouded by controversy. Nanotube cost, polydispersity in nanotube type, and limitations in processing and assembly methods are important barriers for some applications of single-walled nanotubes.