Steady state and dynamic properties of journal bearings in laminar and superlaminar flow regimes. II - Full floating ring bearings

Steady state and dynamic properties of journal bearings in laminar and superlaminar flow regime

Spinon-Holon binding in t−Jt-J model

Using a phenomenological model, we discuss the consequences of spinon-holon binding in the U(1) slave-boson approach to $t-J$ model. Within a small $x$ ($x=$ hole concentration) expansion, we show that spinon-holon binding produces a pseudo-gap normal state with a segmented Fermi surface and the superconducting state is formed by opening an "additional" d-wave gap on the segmented Fermi surface. The d-wave gap merge with the pseudo-gap smoothly as temperature $T\to0$. The quasi-particles in the superconducting state are coupled to external electromagnetic field with a coupling constant of order $x^{\gamma}$ where $0\leq\gamma\leq1/2$, depending on the strength of the effective spinon-holon binding potential.Comment: 9 pages, 3 figure

Supersymmetric Mean-Field Theory of t-J Model

The supersymmetric formulation of t-J model is studied in this paper at the mean-field level where $\delta$-T phase diagram is computed. We find that slave-fermion-like spiral phase is stable at low doping concentration, and the slave-boson-like d-wave fermionic spin pairing state becomes energetically favourable when $\delta\geq$ 0.23. An improvement in free energy using Gutzwiller's method lowers the transition doping concentration to 0.06. We also point out the existence of new branches of excitations in the supersymmetric theory.Comment: 11 pages and 2 figure

The analysis of non-linear dynamic behavior (including snap-through) of postbuckled plates by simple analytical solution

Static postbuckling and nonlinear dynamic analysis of plates are usually accomplished by multimode analyses, although the methods are complicated and do not give straightforward understanding of the nonlinear behavior. Assuming single-mode transverse displacement, a simple formula is derived for the transverse load displacement relationship of a plate under in-plane compression. The formula is used to derive a simple analytical expression for the static postbuckling displacement and nonlinear dynamic responses of postbuckled plates under sinusoidal or random excitation. Regions with softening and hardening spring behavior are identified. Also, the highly nonlinear motion of snap-through and its effects on the overall dynamic response can be easily interpreted using the single-mode formula. Theoretical results are compared with experimental results obtained using a buckled aluminum panel, using discrete frequency and broadband point excitation. Some important effects of the snap-through motion on the dynamic response of the postbuckled plates are found