Nagoya Institute of Technology

About: Nagoya Institute of Technology is a education organization based out in Nagoya, Japan. It is known for research contribution in the topics: Thin film & Catalysis. The organization has 10766 authors who have published 19140 publications receiving 255696 citations. The organization is also known as: Nagoya Kōgyō Daigaku & Nitech.

Sol-gel derived gold nanoclusters in silica glass possessing large optical nonlinearities

Abstract: Sol−gel derived gold/silica glasses, starting with Au sols prepared by two different methodologies, one without the aid of any external stabilizing agent and the other with silica-coated Au, are described. The optical absorption spectra show the typical surface plasmon resonance for Au at around 520−530 nm. Transmission electron microscopy reveals the existence of spherical Au particles in the silica matrix. The mean diameters of Au nanoclusters in gels and glasses vary from 10 to 20 nm and from 27 to 38 nm, respectively, supported by X-ray diffraction data. The third-order optical nonlinearities |χ(3)| determined by a degenerate four-wave mixing (DFWM) method exhibit a higher value of 2.2 × 10-9 esu for a glass with 0.5 wt % Au heated at 600 °C indicating that a larger size induces an enhancement effect. This method also offers a greater χ(3)/α (α: absorption coefficient) value of 1 × 10-11 esu cm, which is comparable to those values obtained by a sputtering method. Thus, these novel Au−SiO2 nanocomposi...

Estimation of surface excitation correction factor for 200-5000 eV in Ni from absolute elastic scattering electron spectroscopy

Abstract: We have determined the surface plasmon excitation correction (SEC) factor for nickel in the 200-5000 eV range from the ratios of the absolute elastic scattering electron intensities measured by a novel cylindrical mirror analyser and those by the Monte Carlo method The inelastic mean free paths (IMFPs) of nickel used for the Monte Carlo method in the energy range specified were calculated by the Penn algorithm The resulting SECs were smaller than the values calculated from Chen and Oswald general equations of surface excitation parameters (SEPs), which describe the influence of surface plasmon excitations by electrons crossing a solid surface We also found that SEPs (obtained from SECs) could be fitted to the equation P s (α, E) = C/[E n cos(α) + C] or P s (α, E) = aE -b / cos(α) (<7% root-mean-square error) in the 200-5000 eV energy range, where P s is the SEP, a is the surface crossing angle of the electron to the surface normal, n(= 041), C(= 539), a(= 17) and b(= 029) are parameters and E is the electron energy

Investigations on the structural, optical and electronic properties of Nd doped ZnO thin films

Abstract: We report the synthesis and characterization of Nd doped ZnO thin films grown on Si (1 0 0) substrates by the spray pyrolysis method. The surface morphology of these thin films was investigated by scanning electron microscopy and shows the presence of randomly distributed structures of nanorods. Grazing angle x-ray diffraction studies confirm that the doped Nd ions occupied Zn sites and these samples exhibited a wurtzite hexagonal-like crystal structure similar to that of the parent compound, ZnO. The micro-photoluminescence measurement shows a decrease in the near band edge position with Nd doping in the ZnO matrix due to the impurity levels. The near-edge x-ray absorption fine structure (NEXAFS) measurements at the O K edge clearly exhibit a pre-edge spectral feature which evolves with Nd doping, suggesting incorporation of more charge carriers in the ZnO system and the presence of strong hybridization between O 2p‐Nd 5d orbitals. The Nd M5 edge NEXAFS spectra reveal that the Nd ions are in the trivalent state. (Some figures in this article are in colour only in the electronic version)

Coalition structure generation based on distributed constraint optimization

Abstract: Forming effective coalitions is a major research challenge in AI and multi-agent systems. Coalition Structure Generation (CSG) involves partitioning a set of agents into coalitions so that social surplus (the sum of the rewards of all coalitions) is maximized. A partition is called a coalition structure (CS). In traditional works, the value of a coalition is given by a black box function called a characteristic function. In this paper, we propose a novel formalization of CSG, i.e., we assume that the value of a characteristic function is given by an optimal solution of a distributed constraint optimization problem (DCOP) among the agents of a coalition. A DCOP is a popular approach for modeling cooperative agents, since it is quite general and can formalize various application problems in MAS. At first glance, this approach sounds like a very bad idea considering the computational costs, since we need to solve an NP-hard problem just to obtain the value of a single coalition. To optimally solve a CSG, we might need to solve O(2n) DCOP problem instances, where n is the number of agents. However, quite surprisingly, we show that an approximation algorithm, whose computational cost is about the same as solving just one DCOP, can find a CS whose social surplus is at least max(2/n, 1/(w*+1)) of the optimal CS, where w* is the tree width of a constraint graph. Furthermore, we can generalize this approximation algorithm with a parameter k, i.e., the generalized algorithm can find a CS whose social surplus is at least max(2k/n, k/(w*+1)) of the optimal CS by exploring more search space. These results illustrate that the locality of interactions among agents, which is explicitly modeled in the DCOP formalization, is quite useful in developing efficient CSG algorithms with quality guarantees.