Yang-Mills Connections on Nonorientable Surfaces

In "The Yang-Mills equations over Riemann surfaces", Atiyah and Bott studied Yang-Mills functional over a Riemann surface from the point of view of Morse theory. We generalize their study to all closed, compact, connected, possibly nonorientable surfaces. We introduce the notion of "super central extension" of the fundamental group of a surface. It is the central extension when the surface is orientable. We establish a precise correspondence between Yang-Mills connections and representations of super central extension. Knowing this exact correspondence, we work mainly at the level of representation varieties which are finite dimensional instead of the level of strata which are infinite dimensional.Comment: 45 pages, 1 figur

Collateral Value and Forbearance Lending

We investigate the foreclosure policy of collateral-based loans in which the endogenous collateral value plays a crucial role. If creditors are able to commit, then the equilibrium arrangement is more likely to feature forebearance lending by specifying a lower level of liquidation (or roll over all of the loans) relative to the expost efficiency criterion for each realization of the interim signal. The key is that collateral value may drop too low when banks call in loans by auctioning off borrowers¿ collateral and this makes clearing up non-performing loans less attractive. We attribute the banks¿ leniency as we have observed in Japan during the 1990s to an equilibrium arrangement where banks can commit due to either relationship banking or an implicit lenderborrower contract, such as the arrangement under Japan¿s main-bank system.Collateral value, forbearance lending, government guarantee.

Application of nuclear technology to different countries

http://www.worldcat.org/oclc/1769943

Flowmeter for large-scale pipes

AbstractThis paper studied a new type of flowmeter, the bypass flowmeter. It is suitable for large-scale pipes. The principle of bypass flowmeter is studied by analyzing flowing in parallel pipes and carrying out experiments at a modified performance test system for centrifugal pumps. The study results showed that the flowrate ratio between the main pipe and the bypass pipe is determined by the geometric structures of pipes and the flowing states in the pipes. The flowrate ratio varies greatly when the Reynolds numbers are relatively lower both in the main pipe and the bypass pipe. The flowrate ratio keeps constant when the Reynolds number in the main pipe is larger than 120000. The head loss becomes smaller when the bypass pipe is connected to the main pipe. The percentage of head loss decrease is from 7.64% to 9.34%. The results indicate that bypass flowmeter is suitable for flowrate measuring in large scale pipes. It will not cause additional head loss to the flow