In Situ Charge Characterization of TiO<Subscript>2</Subscript> and Cu–TiO<Subscript>2</Subscript> Nanoparticles in a Flame Aerosol Reactor

Charge distribution characteristics were investigated for nanoparticles synthesized in a diffusion flame aerosol reactor. The nanoparticles considered were pristine TiO₂ and Cu–TiO₂, with Cu dopant concentrations ranging from 1 to 5 wt% with particle size from 25 to 60 nm. In situ measurements were conducted by integrating a tandem differential mobility analyzer (TDMA) experimental setup with the flame aerosol reactor. A charging model was used to identify the important parameters that govern the two charging mechanisms (diffusion and thermo-ionization) in the flame and their relative importance at different operating parameters. The results indicate that TiO₂ and Cu–TiO₂ nanoparticles carry single as well as double unit charges. The charged fraction depends on particle size as well as on dopant concentration. The charged fraction increased with increasing particle size and decreased with copper dopant concentration. Measured charged fractions were similar for both the polarities at different mobility diameters. Based on the flame operating parameters, the calculations indicate that diffusion charging is dominant in the flame, which is consistent with the experimental results.     

Morse theory for the space of Higgs <Emphasis Type="Italic">G</Emphasis>–bundles

Fix a C ^∞ principal G–bundle E⁰_G{E^0_G} on a compact connected Riemann surface X, where G is a connected complex reductive linear algebraic group. We consider the gradient flow of the Yang–Mills–Higgs functional on the cotangent bundle of the space of all smooth connections on E⁰_G{E^0_G}. We prove that this flow preserves the subset of Higgs G–bundles, and, furthermore, the flow emanating from any point of this subset has a limit. Given a Higgs G–bundle, we identify the limit point of the integral curve passing through it. These generalize the results of the second named author on Higgs vector bundles.     

Erratum to: Risk-Sensitive Control with Near Monotone Cost

The infinite horizon risk-sensitive control problem for non-degenerate controlled diffusions is analyzed under a ‘near monotonicity’ condition on the running cost that penalizes large excursions of the process.     

1-Soliton solution of the generalized KP equation with generalized evolution

This paper obtains the 1-soliton solution of three variants of the generalized KP equation with generalized evolution. The solitary wave ansatz is used to carry out the integration of such equations. The parameter domain is also identified in the process. The numerical simulations are also obtained in this paper.     

1-Soliton solution and conservation laws for nonlinear wave equation in semiconductors

This paper obtains the 1-soliton solution of a nonlinear wave equation that arises in the study of semiconductors. The conserved quantities are also calculated from this equation. Furthermore, additional non-trivial conserved quantities are computed using the invariance and multiplier approach based on the well known result that the Euler-Lagrange operator annihilates the total divergence.     

Azimuthal correlation and fractal study of compound hadrons (pions and protons) at Dubna and SPS energy

This paper presents an investigation of compound hadrons (pions and protons) distribution emitted from ²⁴Mg-AgBr and ¹²C-AgBr interactions both at 4.5 AGeV and ³²S-AgBr interactions at 200 AGeV. The study includes azimuthal correlations (two particle and three particle), azimuthal asymmetry and fractal behaviour. This paper reveals some interesting results.     

Third Joint ESF–NSF Symposium on ‘Nanoparticles: Applications in Materials Science and Environmental Science and Engineering,’ Dublin,Ireland, September 6, 2000

Journal of Nanoparticle Research -     

Kaluza-Klein space and strong gravity

A study of strong gravity theory is carried out in five-dimensional Kaluza-Klein space-time. A relation between the cosmological constant and the radius parameter of the fifth dimension is obtained. The effect of the extra dimension is seen through the generation of masses simulating a Regge-like mass spectrum. It is found that the confinement mechanism is built into the strong gravity formalism. We also discuss the trapping of quarks in the 5D background.     

Synthesis and electrical and optoelectronic properties of poly[(N-benzyldiphenylamino)methane]

Poly[(N-benzyldiphenylamino)methane] was synthesized by the condensation polymerization of benzyldiphenylamine and formalin (30% HCOH in water) and examined for electrical and optoelectronic properties. Dark conductivity and photoconductivity of the polymer film were investigated by steady-state measurements. Current-voltage characteristics and intrinsic photoconduction of the polymer in the visible wavelength range were studied. A superlinear current increase is tentatively explained in the light of the Poole-Frenkel effect. Dielectric constant and dielectric loss parameters of the polymer are independent of frequency (50 Hz–10 kHz) and temperature (273–323 K), respectively. The growth and decay rates of the photocurrent depend on the applied voltage, and the photocurrent varies directly with the light intensity. The activation energies for dark conductivity and photoconductivity are 1.16 eV and 1.05 eV, respectively, and the optical energy band gap as evaluated from absorption coefficient spectra is 2.86 eV.