Essay: Qiu Z(h)i-Jie: Artist as the Writing Hand

The document is printed except for a trivial amendment on the second page. (Jerry Wu\u2723).https://digital.kenyon.edu/zhoudocs/1216/thumbnail.jp

A nonlinear theory for a flexible unsteady wing

This paper extends the previous studies by Wu [Wu TY (2001) Adv Appl Mech 38:291–353; Wu TY (2005) Advances in engineering mechanics—reflections and outlooks. World Scientific; Wu TY (2006) Struct Control Health Monit 13:553–560] to present a fully nonlinear theory for the evaluation of the unsteady flow generated by a two-dimensional flexible lifting surface moving in an arbitrary manner through an incompressible and inviscid fluid for modeling bird/insect flight and fish swimming. The original physical concept founded by Theodore von Kármán and William R. Sears [von Kármán T, Sears WR (1938) J Aero Sci 5:379–390] in describing the complete vortex system of a wing and its wake in non-uniform motion for their linear theory is adapted and extended to a fully nonlinear consideration. The new theory employs a joint Eulerian and Lagrangian description of the wing motion to establish a fully nonlinear theory for a flexible wing moving with arbitrary variations in wing shape and trajectory, and obtain a fully nonlinear integral equation for the wake vorticity in generalizing Herbert Wagner’s [Wagner H (1925) ZAMM 5:17–35] linear version for an efficient determination of exact solutions in general

Comment on Cyclic quantum-evolution dependence on the Hamiltonian and geometric phase

It is shown that the analysis and the main result of the article by L-A. Wu [Phys. Rev. A 53, 2053 (1996)] are completely erroneous.Comment: LaTeX file, 2 page

NEW METHODS FOR SOLVING ALGEBRAIC EQUATIONS

Iteration methods are very useful in solving nonlinear algebraic equations. The most famous such method is Newton’s method deduced by first order Taylor expansion. In 2003, J. H. He gives a new faster convergent method, based on second order Taylor expansion, that gives a quadratic equation for the iterations difference xn+1-xn . However He’s method is not applicable when this equation has complex roots. In 2008, D. Wei, J. Wu and M. Mei eliminated this deficiency, obtaining from third order Taylor expansion a cubic equation, that always has a real root. In this paper, we present the three methods and their applications to some particular equations.equations

Some remarks on topological 4d-gravity

We show that the method of S. Wu to study topological 4d-gravity can be understood within a now standard method designed to produce equivariant cohomology classes. Next, this general framework is applied to produce some observables of the topological 4d-gravity.Comment: 10 pages, Late

General Volume-Preserving Mechanical Systems

In this letter, we present the general form of equations that generate a volume-preserving flow on a symplectic manifold (M, \omega). It is shown that every volume-preserving flow has some 2-forms acting the role of the Hamiltonian functions in the Hamiltonian mechanics and the ordinary Hamilton equations are included as a special case with a 2-form \frac{1}{n-1} H \omega where H is the corresponding Hamiltonian.Comment: Plain LaTeX, 13 pages, no figure