Abstract: The present invention relates to a preparation and purification method for cationic quaternary ammonium salt of sodium hyaluronate in homogeneous medium. By adding a homogeneous solvent and a sodium hyaluronate solid to a vessel, heating the vessel until the contents are dissolved to form a homogeneous system, adding an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride (GTA) to the homogeneous system, then adding a base catalyst, and stirring at a preset temperature to carry out a graft reaction, a graft product is obtained wherein 2,3-epoxypropyltrimethylammonium chloride is grafted to the oxygen atom of the hydroxymethyl group of sodium hyaluronate. By using the method, a graft product wherein 2,3-epoxypropyltrimethylammonium chloride is grafted to the oxygen atom of the hydroxymethyl group of sodium hyaluronate is obtained. Addition of salts is avoided during the reaction, a grafting yield up to 0.69 is obtained, and coagulation occurred to the product is effectively solved.

Abstract: A method for demonstrating a new scientific discovery made by the inventor about the nonlinear instability of vehicles, like aircrafts, automobiles and ocean vehicles. Said method includes a model and a three-gimbaled framework that permits said model to respond to inertial moments about the axes of which the moments of inertias are the smallest and the largest, wherein said model has restoring and damping capabilities along these two axes. Said method also comprises how to use a variable motor or a crank for controlling said model rotational motions about the intermediate principal axis of inertia with closed form formulas for the external driven frequencies and amplitudes to be used to excite the nonlinear instabilities of said model. Said model could be an aircraft, an automobile, a ship, or even a rectangular block.

Abstract: A vehicle nonlinear dynamics experimental simulation device, such as flight simulator, including a motorized spherical vehicle suspended inside a spherical shell which has a smooth inner surface. The spherical vehicle is supported by a plurality of spiky legs with bearing assemblies. The spherical shell is supported by three controllable translational motion platforms. Simulating apparatuses for a pilot cabin is mounted inside the spherical vehicle. The spherical vehicle has driving, restoring, and damping capabilities in roll, pitch, and yaw directions and is capable of unbounded rotation in any directions. The spherical vehicle provides an experimental model to simulate a vehicle's rotational dynamics.

Abstract: A system and a method to warn a ship crew of potential violent motions in the immediate near future for the oceangoing vessel when operating in seas. Violent ship motions not only discomfort ship crews, damage cargos and ship structures, but also pose potential capsizing risk to ships. The system includes motion sensors; computer hardware and software; and warning devices. The sensors measure the ship roll, pitch, yaw, and rudder motions. The time histories of these motions are stored in the hardware and constantly analyzed using Finite Fourier Transform by Fast Fourier Transform (FFT) to detect the nonlinear inertial coupling effect which is newly discovered by the inventor and believed to be the root cause leading to violent motions and capsizing.

Abstract: A system and method for predicting aircraft nonlinear instability includes the steps of: (1) a pre-built aircraft state parameters for all possible flight conditions, (2) real time measuring flight parameters to determine aircraft state, (3) calculating the inertial coupling frequencies and periods as well as the nonlinear instability threshold based on the nonlinear instability theory recently developed by the inventor, (4) providing a first warning signal if the threshold is approached, (5) providing a second warning signal if the threshold has been exceeded.

Abstract: A system and a method to warn a ship crew of potential violent motions in the immediate near future for the oceangoing vessel when operating in seas. Violent ship motions not only discomfort ship crews, damage cargos and ship structures, but also pose potential capsizing risk to ships. The system includes motion sensors; computer hardware and software; and warning devices. The sensors measure the ship roll, pitch, yaw, and rudder motions. The time histories of these motions are stored in the hardware and constantly analyzed using Finite Fourier Transform (FFT) to detect the nonlinear inertial coupling effect which is newly discovered by the inventor and believed to be the root cause leading to violent motions and capsizing.

Abstract: A system and method for predicting aircraft nonlinear instability includes the steps of: (1) a pre-built aircraft state parameters for all possible flight conditions, (2) real time measuring flight parameters to determine aircraft state, (3) calculating the inertial coupling frequencies and periods as well as the nonlinear instability threshold based on the nonlinear instability theory recently developed by the inventor, (4) providing a first warning signal if the threshold is approached, (5) providing a second warning signal if the threshold has been exceeded.

Abstract: A vehicle nonlinear dynamics simulation device, such as flight simulator, including a motorized spherical vehicle suspended inside another spherical shell which has smooth inner surface. The spherical vehicle is supported by a plurality of spiky legs of either air-bearing assemblies or omni-directional ball bearing assemblies. The outer spherical shell is supported by three controllable translational motion platforms. Simulating equipment for a pilot cabin is mounted inside the spherical vehicle. The spherical vehicle has driving, restoring, and damping capabilities in roll, pitch, and yaw directions and is capable to rotate 360° in any directions. Therefore it provides a dynamically equivalent model to simulate a vehicle rotational dynamics. The driving and restoring means include Omni wheel assemblies mounted outside of the spherical vehicle and operable to contact the inner surface of the shell to drive the spherical vehicle in roll, pitch, and yaw directions. The driving means include electrical motors.

Abstract: An apparatus and a method for demonstrating a new scientific discovery made by the inventor about the nonlinear instability of vehicles, like aircrafts, automobiles and ocean vehicles. The apparatus comprises a model and a three-gimbaled framework that permits the model to respond to inertial moments about the axes of which the moments of inertias are the smallest and the largest. In these two axes, the apparatus has restoring and damping capabilities. The apparatus also comprises external driven mechanisms to rotate the model about the intermediate principal axis of inertia. A method with closed form formulas for the external driven frequencies and amplitudes to be used to excite the nonlinear instabilities of the model is given. The model could be an aircraft, an automobile, a ship, or even a rectangular block.