A favorable borate anionic group can be selected as the basic structural unit for VUV NLO materials, in terms of the properties of known inorganic NLO crystals and the features of their anionic groups, based on anionic group theory from SHG coefficients, UV absorption edge and moderate birefringence. Considering the coordination chemistry of atoms in some inorganic compounds, and the relationship between a noncentrosymmetric structural arrangement and the composition of compounds, a suitable theoretical model that aids the search for new VUV NLO materials has been proposed. The model compounds, formulated as MxA1,2(BO3)1,2Oy, may be prospective candidates for new VUV NLO materials considering their SHG coefficients, UV absorption edge, and moderate birefringence. The model suggests that investigation for a new VUV NLO material would be profitably conducted by focusing on boroberylate, boroaluminate, and borophosphate, on the basis of anionic group theory. For example, a novel noncentrosymmetric beryllium borophosphate compound, Be3BPO7 was synthesized by solidstate reaction. Microcrystalline Be3BPO7 has a hexagonal system and contains the BO3 anionic group as its basic structural unit, which should play an important role for SHG coefficients. In fact, Be3BPO7 powder was found to have a significant SHG effect.

The main issues related with preparation of nanocomposites are dispersion, alignment and adhesion between carbon nanotubes and matrix. We are designing an approach where these issues are fully addressed. We combined a functionalization approach with in-situ technique of nanocomposites preparation. A good dispersion and intercalation of carbon nanotubes were observed in the prepared nanocomposites. A presence of strong interfacial region was also noted. It is also found that orientation of carbon nanotubes inside matrix can be done by mechanically stretching of nanocomposites. DSC analysis shows that inclusion of carbon nanotubes affects crystallization behavior of nylon 6 significantly and it is found that CNTs acts as nucleating agents.

Nowadays the demands placed upon the tooling in processes such as cutting, drilling, milling, stamping, bending, etc. are constantly growing and restrictive. On one hand, productivity, cost efficiency and quality all require high-speed processes to be developed. On the other hand, environmental safety requires very little or no lubricant to be used (dry cutting or minimized spray-lubrication). When combined, these two considerations mean: the tool should wear very little, withstand high temperatures and the friction between the tool and the work piece should be minimized. An apparent approach to simultaneously satisfying such requirements is coating the tools with self-lubricating hard coatings. Quaternary TiAlCN is a rapidly developing hard coating suitable for a number of cutting applications. The well-known wear-resistant coating TiN has been demonstrated to have improved high-temperature oxidation resistance when aluminum is included, i.e. TiAl N. Addition of yet a fourth element, carbon, has the primary effect of lowering the high friction coefficient occurring between the ceramic coating and steel. The high hardness, toughness, heat resistance and low friction coefficient of TiAlCN make it the ideal candidate for applications such as milling, hobbing, tapping, stamping and punching. MoS2 is a well-known solid lubricant widely used as tribological coatings, especially for applications working in vacuum or dry environment. Combining the wear resistance of the quaternary TiAlCN matrix with the lubricating properties of MoS2 has an extremely beneficial effect in further improving the tribological performance of the resulting composite. The coatings were deposited on hardmetal (WC-Co) and Si (100) substrates using reactive magnetron sputtering. The structure of the coatings is studied by plain-view TEM and XTEM, electron diffraction and ED X. The tribological properties were examined by Pin-on-Disk (PoD) tribometer. The adhesion was estimated by scratch test, and the hardness was measured by nanoindentation. All the coatings examined had a very low friction coefficient (typically below 0.09) and volumetric wear rate against 100Cr6 steel (AISI 52100) of 7.10-7 mm3/N/m. The relation of deposition parameters to structure to properties is discussed. To the authors knowledge, this is the first paper describing quaternary TiAlCN matrix with inclusions of MoS2.

Ordered mesoporous silica (OMS) adsorbents were prepared by grafting amino, carboxylic and thiol-containing functional groups onto MCM-41 for the selective removal of dye and metal pollutants from wastewater. The amino containing OMS-NH2 adsorbent has a large adsorption capacity and a strong affinity for the Acid blue 25. It can selectively remove Acid blue 25 from a mixture of dyes (i.e., Acid blue 25 and Methylene blue). The OMS-COOH is a good adsorbent for Methylene blue displaying excellent adsorption capacity and selectivity for the dye. The chemically modified OMS adsorbents were also tested for the selective removal and recovery of metals (i.e., lead and copper). The OMS-SH adsorbent can selectively remove lead from solutions containing Pb2+ and Cu2+ ions, whereas the OMS-NH2 selectively adsorbed a large quantity of copper. The selectivity of the adsorbents for lead and copper is strongly influenced by pH. Indeed, by simply adjusting the pH, OMS-NH2 can adsorb mainly lead or copper from a mixture containing both metals.

Polymer materials such as Kevlar that are susceptible to UV degradation may be protected by appropriate coatings. We are using zinc oxide and titanium dioxide nanoparticles with an average particle size ranging from 25 to 70 nm. Five weight percent nanoparticles were dispersed in acrylic coatings, the dispersion is assisted by addition of a non-ionic surfactant, mechanical stirring and ultrasonication. The UV protective mechanism of nanoparticle-embedded coatings is theoretically explained using Mie theory. We estimated the minimum thickness of a 5 weight % nanoparticle-embedded coatings that is required to prevent the UV radiation from reaching the base of the substrate. Results obtained from nanoparticle-embedded acrylic-coated Kevlar fabric and neat acrylic-coated Kevlar fabric after exposure to UV radiation in QUV weatherometer show that the nanoparticle coating offers protection. UV-visible spectroscopy was used to obtain quantitative results.

Tubular and platelet graphite nanofibers were used as catalysts for the oxidative dehydrogenation of ethylbenzene to produce styrene at temperatures between 350 and 577 °C in packed bed tubular quartz flow reactors. The performances of GNF catalysts were evaluated in terms of conversion, selectivity and styrene yield. Tubular GNF showed higher activity than platelet GNF, but the latter showed higher selectivity than the former material. Both types of GNF exhibited significantly better performance than a commercial catalyst when operated under the same conditions.

Bramble-like mesostructured nickel oxide/surfactant fibers were synthesized by using anionic surfactants (sodium dodecylsulfonate or sodium dodecylsulfate: SDS) as templates, and nickel salts as inorganic precursors, via the “S-I+” route in alkaline condition. The as-prepared samples were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetry-differential thermal analysis (TG/DTA) techniques. Such form of mesostructure nickel oxide is found for the first time and is believed to have potential applications in catalysis, host-guest chemistry, and electrochemical devices.

Although advances have been made in the synthesis of raw carbon nanotube (CNT) materials, the lack of efficient processes for assembly and integration of CNTs into functional forms has hindered the development of CNT-based devices. Here we report a dielectrophorestic method to manipulate, align and assemble CNTs into one-dimensional nanostructures using an alternating-current electric field. Pre-formed CNTs dispersed in water are assembled into micro-electrodes and sub-micron diameter fibrils with variable lengths from 1 μm to over 1 cm. The CNTs within the fibril are bonded by van der Waals forces and are aligned along the fibril axis. This method affords fine control of the fibril length and is capable of parallel fabrication of multiple fibrils using the same material source. The short CNT fibrils can potentially be used as probes for scanning probe microscopes and the long ones as electrodes or conducting nanowires.

We have controllably grown carbon nanotubes using uniformly distributed cobalt nanoparticles as catalyst. Cobalt nanoparticles with a uniform size were synthesized by chemical reaction and colloidal solutions including the cobalt nanoparticles were prepared. The cobalt nanoparticles were uniformly distributed on silicon substrates by a spin-coating method. Carbon nanotubes with a uniform diameter were synthesized on the cobalt nanoparticles by thermal chemical vapor deposition of acetylene gas. The density and vertical alignment of carbon nanotubes could be controlled by adjusting the density of Co nanoparticles.

Under oxidizing preparation conditions the magnetite (111) surface reconstructs to a highly ordered superlattice. This surface reconstruction represents an oxygen-termination of the magnetite bulk. We employ spin-polarized (SP) STM to study the spin-dependent tunnelling between a magnetite (111) sample and an antiferromagnetic tip through a vacuum barrier. Atomic scale STM images show significant magnetic contrast corresponding to variations in the local surface states induced by oxygen vacancies. The local variations of the tunnelling magnetoresistance around these vacancies correspond to 150%. By employing SP-STM measurements and First principles calculations we could conclude that an oxygen top-layer considerably changes the SP properties of the magnetite surface. We explain the appearance of the superstructure in terms of electron-lattice instability due to the surface strain.

The sol gel reaction of NH4VO3 and polymethylmethacrylate (PMMA) template followed by hydrothermal treatment formed (NH4)xV2O5-Δ.nH2O rods. TGA, SEM, XRD and FTIR characterized this compound. Heating (NH4)xV2O5-Δ.nH2O in oxygen and nitrogen at 250 °C and 300 °C respectively resulted in the formation of vanadium oxides nanofibers of V3O7 and V2O5. Performance of these compounds as cathode in rechargeable lithium battery was investigated in a LiPF6/mixed carbonate electrolyte. The materials show good cycling with capacity greater than 130mAh/g, which translates to the insertion of 0.5 moles of Li+ per vanadium of the active material.

A level set approach was used to study photonic band gaps for dielectric composites with symmetries of the eleven face centered cubic lattices. Candidate structures were modeled for each group by a 3D surface given by f(x,y,z)-t=0 obtained by equating f to an appropriate sum of structure factor terms. This approach allows us to easily map different structures and gives us an insight into the effects of symmetry, connectivity and genus on photonic band gaps. It is seen that a basic set of symmetries defines the essential band gap and connectivity. The remaining symmetry elements modify the band gap. The eleven lattices are classified into four fundamental topologies on the basis of the occupancy of high symmetry Wyckoff sites. Of the fundamental topologies studied, three display band gaps--- including two: the (F-RD) and a group 216 structure that have not been reported previously.

Hydroxyapatite (HAp) – Hyaluronic acid (HYA) nano composite sol was prepared at room temperature, at pH 8, by a coprecipitation method from CaCl2 or Ca(CH3COO)2 and H3PO4. These soluble Ca sources were used in order to increase the number of nucleation sites for HAp on HYA. Starting materials were supplied by two kinds of processes to give solution(s) of only PO43- or, PO43- and Ca2+ simultaneously into HYA solution containing Ca2+. Morphology of the aggregates and crystallite size as well as lattice parameters of the HAp were examined by TEM and XRD data with Rietveld refinement. We observed needle like aggregates of crystallites of HAp. Supplying methods of Ca sources controlled the aspect ratio of the aggregates and HAp crystallite. Lattice parameters of the samples prepared from CaCl2 shifted towards those of chloroapatite. Those from Ca(CH3COO)2, however, correspond to the literature values of single crystal HAp. The results of FT-IR spectra and the changes of rheological property indicate the electrostatic interactions between negatively charged functional groups of HYA and HAp.

Hydrogen plasma treatments applied on standard Czochralski silicon (Cz Si) wafers cause a structuring of the surface regions on the sub-100 nm scale, i.e. a thin ‘nano-structured’ Si layer is created up to a depth of ∼ 150 nm. The formation of the ‘nano-structures’ and their evolution in dependence on the process conditions was studied. The impact of post-hydrogenation annealing on the morphology of the structural defects was studied up to 1200 °C. The H-plasma treated and annealed samples were analyzed at surface and sub-surface regions by scanning electron microscopy (SEM), atomic force microscopy (AFM), and μ-Raman spectroscopy.

Properties of electronic energy spectra of several small virtual clusters (known as small quantum dots, or QDs) composed of In, Ga and As atoms are investigated for the further use in nanoheterostructure (NHS) units of pre-designed electronic properties. Modern quantum statistical physics methods relate these properties to electronic transport properties of such systems and therefore, lead to realization of a virtual (i.e., fundamental theory- based, computational) approach to synthesis of sub-nanoscale electronic materials with pre-designed electronic properties[1].

Nanodisperse many-particle-systems (MPS), often forming compact matter, consist of atomic/molecular nano-sized building units, which interact with each other. The interactions among clusters and with the embedding matrix mainly determine the macroscopic properties of the material. The functional properties of nanostructured matter depend on a number of parameters that describe the single cluster (structure, chemical composition, size and shape), the near-order and far-order effects of a given cluster and which can be modeled using the concept of MPS. The specified parameters have to be considered in a detailed multilevel ultramicroscopic and analytical characterization, and several can be manipulated to tailor new materials with desired optical, electronic or catalytic properties. Such approach provides logical synergism between modeling, engineering and characterization of disperse composite nanomaterials by the combination of analytical electron microscopy and image analysis techniques, as illustrated by examples utilizing chemically stabilized “giant” clusters of noble metals and multifractal percolation nanostructures of Ag filaments.

Mixture films of Co and C60 with various compositions were fabricated by co-evaporation under UHV condition. As for the saturation composition with C60-based phase, Co5C60 is deduced from the systematic Raman analysis. It is reasonably interpreted that the C60-based phase can be realized by less than one electron transfer per a Co atom into C60 and the contribution of a covalent bonding which induces a differently coordinated structure of the C60 molecules from the fcc-C60. The electrical conduction features are dependent on the Co content. In the C60-based phase up to Co5C60, the conduction mechanism seems to be described by the band concept modified with the disorder, followed by the hopping conduction through the precipitated Co clusters or particles and then, by the metallic one with increasing Co content.

Polypropylene nanocomposites were prepared using zinc oxide as the filler by melt mixing process. Nanocomposites were also prepared using maleic anhydride grafted polypropylene and methylated-zinc oxide using the same method. The samples were analyzed for observing changes in morphology and thermal stability using various characterizing instruments. The results showed that zinc oxide induced changes in the morphology and thermal stability of polypropylene, though by varying amounts depending on the type of nanocomposite prepared. The nanocomposites prepared from g-PP and methylated zinc oxide showed significant changes in crystallization temperature, decomposition temperature and residue formed upon decomposition, as compared to the rest of the composites or control samples. This was attributed to higher degree of interaction existing at the interphase between the organic and inorganic phases for these nanocomposites.

Nanophase Technologies Corporation (NTC) employs a new physical vapor synthesis technique to manufacture ceria-based mixed rare earth oxide nanomaterials. The mixed rare earth oxide nanoparticles are nonporous, dense, discrete crystals. The compositions are solid solutions that remain thermally stable to above 1050°C.

Ceria is an active oxygen storage material. Doping ceria with other rare earth metals enhances the thermal stability of nanocrystalline particle size and increases the oxygen storage capacity (OSC). The mean particle size and OSC of ceria-based mixed rare earth oxides are presented as a function of particle composition, morphology, and thermal history.

These materials are commercially available and are being engineered for several applications including oxygen storage catalysts and polishing materials.

Nanocrystalline stoichiometric FeCo powders were prepared by mechanically alloying elemental Fe and Co powders using a high-energy ball mill. The microstructural evolution was studied as a function of milling time and subsequent annealing using X-ray diffractometry and differential scanning calorimetry. The magnetic behavior of the specimens was characterized using a vibrating sample magnetometer and a magnetic force microscope. A reduction in grain size coupled with an increase in coercivity was observed as function of milling time. The smallest grain size of 4 nm, which exhibited a coercivity of 122 Oe and magnetization of 2 T at room temperature, was obtained after 240 h of milling. The reduction in grain size during milling was not accompanied by enhanced soft magnetic properties.