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To predict the maneuverability of full-revolving propeller ships, this paper analyzes the propeller force and establishes MMG equations for controlling motion mathematical models that are suited to the full-revolving propeller model, in accordance with the modeling method of the separating ship motion model and taking into account the special nature of the force and flexibility of a full rotation in the horizontal plane of a full-revolving propeller. Secondly, hydrodynamic force derivatives for the ship model are obtained by simulating the model's PMM movement, and the controlling Ordinary Differential Equation (ODE) is solved using the four-stage Rung-Kuta method. Finally, the numerical simulation of a certain ship's rotating motion and its zigzag test in still water is obtained, and the prediction results are compared with that of a self-running model. It is found that the simulation results agree well with the trial results, and the effectiveness of the ship motion model for the full-revolving propeller model is validated. In brief, this paper provides a reliable and effective method of predicting the maneuverability of full-revolving propeller ships.

The bluish-green KBaY(BO):Eu phosphors were prepared by high-temperature solid state reaction method. The photoluminescence properties, concentration quenching and energy transfer as well as the luminescence decays were investigated. The emission spectrum showed a single intensive band centered at 500 nm, which correspond to the 4 f 5 d → 4 f transition of Eu. The optimal concentration for the luminescence of Eu in KBaY(BO):Eu was determined to be 0.03 mol. The critical energy transfer distance was calculated as 21.34 Å. The corresponding concentration quenching mechanism was verified to be a dipole-dipole interaction. And the blue-shift behavior of KBaY(BO):Eu with increasing temperature was analyzed by the configurational coordinate diagram. The results indicate that the KBaY(BO):Eu phosphors have potential applications as an ultraviolet-convertible phosphor due to its effective excitation in the ultraviolet rang. [ABSTRACT FROM AUTHOR]

A series of Eu2+ and Tb3+ singly-doped and co-doped Sr3Y2(Si3O9)2 (SYSO) phosphors have been synthesized via a conventional high-temperature solid-state reaction. The crystal structures, photoluminescence properties, fluorescence lifetimes, thermal properties and energy transfer of SYSO:Eu2+,Tb3+ were systematically investigated in detail. Rietveld structure refinement of the obtained phosphors indicated that the SYSO host crystallized in a monoclinic system with the space group C2/c (15) and there are three kinds of cation sites for the doped ions to occupy forming emission centers. The photoluminescence (PL) emission bands of SYSO:xEu2+ show a red-shift tendency with increasing Eu2+ content which should be attributed to more Eu2+ ions entering into Sr2/Y2 and Sr3/Y3 sites from the Sr1/Y1 site. For the co-doped SYSO:Eu2+,Tb3+ samples, tunable colors from cyan to green can be realized by varying the doping concentration of the Tb3+ ions. The intense green emission was realized in the SYSO:Eu2+,Tb3+ phosphors on the basis of the highly efficient energy transfer from Eu2+ to Tb3+ with an efficiency of over 89%. As a result, the emission intensity of SYSO:0.01Eu2+,0.21Tb3+ is about 2.5 times higher than that of SYSO:0.21Tb3+ under 340 nm UV excitation. The energy transfer mechanism from Eu2+ to Tb3+ in the SYSO host was ascribed to the quadrupole–quadrupole interactions. These results indicated that the SYSO:Eu2+,Tb3+ phosphors can act as single-phase green emitting phosphors for possible applications in ultraviolet light-based white light-emitting diodes (w-LEDs). [ABSTRACT FROM AUTHOR]