Proton modified Pt zeolite fuel cell electrocatalysts

NaY Zeolite is selected as a suitable material to host 1.5 wt% Platinum (Pt) loading on zeolite using ion exchange method (a) Pt(NH3)4(NO3)2 without excess NH4NO3 nitrate and (b) Pt(NH3)4(NO3)2 with excess NH4NO3 nitrate. The structure/reactivity relationship of Pt nanoparticle has been experimentally studied via Nafion@ bound electrodes to investigate the interaction nature of Pt with zeolite and electron transfer using the extended X-ray adsorption fine structure (EXAFS) and Pt particle was predicted at 0.7 – 1.5 (nm). Pt oxides can be electrochemically reduced via a hydrogen ‘spillover’ phenomenon. A highly dispersed small Pt particle distribution can be achieved with excessive H+ ions on zeolite acidic sites

Current and fluctuation in a two-state stochastic system under non-adiabatic periodic perturbation

We calculate a current and its fluctuation in a two-state stochastic system under a periodic perturbation. The system could be interpreted as a channel on a cell surface or a single Michaelis-Menten catalyzing enzyme. It has been shown that the periodic perturbation induces so-called pump current, and the pump current and its fluctuation are calculated with the aid of the geometrical phase interpretation. We give a simple calculation recipe for the statistics of the current, especially in a non-adiabatic case. The calculation scheme is based on the non-adiabatic geometrical phase interpretation. Using the Floquet theory, the total current and its fluctuation are calculated, and it is revealed that the average of the current shows a stochastic-resonance-like behavior. In contrast, the fluctuation of the current does not show such behavior.Comment: 7 pages, 1 figur

Diffusion-limited loop formation of semiflexible polymers: Kramers theory and the intertwined time scales of chain relaxation and closing

We show that Kramers rate theory gives a straightforward, accurate estimate of the closing time $\tau_c$ of a semiflexible polymer that is valid in cases of physical interest. The calculation also reveals how the time scales of chain relaxation and closing are intertwined, illuminating an apparent conflict between two ways of calculating $\tau_c$ in the flexible limit.Comment: Europhys. Lett., 2003 (in press). 8 pages, 3 figures. See also, physics/0101087 for physicist's approach to and the importance of semiflexible polymer looping, in DNA replicatio

Location decisions and network configurations of foreign investment in urban China

Journal ArticleThis article studies location decisions and network configurations of FDI in Nanjing, the capital of Jiangsu Province, located in the northwest of the Yangtze River Delta (YRD). Built upon the perspective that China?s economic transition can be conceptualized as a triple pr of globalization, marketization, and decentralization, this article outlines four structural changes of the Chinese economy, which are underlying the location and networks of FD decentralization and the empowerment of local states, marketization and the increasing importance of places, globalization and the emergence of globalizing city regions, and urba spatial restructuring. The study has uncovered substantial intraurban differentials existing within Nanjing and the significance of the Chinese state, location within the YRD, and intraurban context in the location decisions of FDI. We have also found that foreign ventures overwhelmingly serve as production facilities for either the Chinese or world market, and maintain close production relations with other foreign firms in the YRD. Lastly, regression models have identified the significance of national-level development zones, access to ports, and industrial land in the location of foreign ventures