Abstract To study the complex mechanism of the high-dimensional nonlinear cable systems, a 3 degree-of-freedom model reduced from the tower-cable-beam structure is proposed and investigated in this paper. Based on the D’Alembert Principle, the dynamic equations of in-plane and out-of-plane vibration are established and simulated by the 4th-order Runge-Kutta method. The results exhibit the phenomenon of coupling internal resonance under the systematical conditions revealed by the analytical analysis on the dynamic equations. The smaller mass ratio of the cable-beam would lead to a greater vibration intensity while the tensile stiffness and initial force of the cable have no significant effect. The in-plane and out-plane cable vibrations are independent, and the internal resonance would not be excited by the harmonic excitation in the cable axis. Additionally, applying damping on any component of the system is verified to be an effective approach to vibration reduction. Compared with ordinary cables, cables with less-weight and high-strength materials would be exited to less vibration intensity under the same external excitation.

Background: D-Hydroxyphenylglycine is considered to be an important chiral molecular building-block of antibiotic reagents such as pesticides, and β-lactam antibiotics. The process of its production is catalyzed by D-hydantoinase and D-carbamoylase in a two-step enzyme reaction. How to enhance the catalytic potential of the two enzymes is valuable for industrial application. In this investigation, an Escherichia coli strain genetically engineered with D-hydantoinase was immobilized by calcium alginate with certain adjuncts to evaluate the optimal condition for the biosynthesis of D-carbamoyl-p-hydroxyphenylglycine (D-CpHPG), the compound further be converted to D-hydroxyphenylglycine (D-HPG) by carbamoylase. Results: The optimal medium to produce D-CpHPG by whole-cell immobilization was a modified Luria-Bertani (LB) added with 3.0% (W/V) alginate, 1.5% (W/V) diatomite, 0.05% (W/V) CaCl2 and 1.00 mM MnCl2.The optimized diameter of immobilized beads for the whole-cell biosynthesis here was 2.60 mm. The maximized production rates of D-CpHPG were up to 76%, and the immobilized beads could be reused for 12 batches. Conclusions: This investigation not only provides an effective procedure for biological production of D-CpHPG, but gives an insight into the whole-cell immobilization technology.