Abstract: The electromagnetic vibration exciter system with an adjustable electro-viscoelastic suspension device comprises an electromagnetic vibration exciter, a power amplifier and an adjustable electro-viscoelastic suspension device, which acts as the suspension device of the electromagnetic vibration exciter. The adjustable electro-viscoelastic suspension device contains a displacement sensor detecting the displacement of the moving component, a first adjustable amplifier and a second adjustable amplifier, a differentiator, an adjustable phase shifter, an adder and a proportioner. The linearity of the stiffness and damping of the exciter system is excellent, which can be adjusted as need through the adjustment of gain of the adjustable amplifier, the proportioner, the adjustable phase shifter. This invention has adjustable and linear parameters and it is also easy to be realized.

Abstract: The vibration exciter system with a feedback control unit based on an optical linear encoder comprises a vibration exciter, a signal generator and a power amplifier. The exciter system further comprises an optical linear encoder converting the displacement of the moving component of the exciter into A/B pulse with a phase difference of 90°, a filtering, shaping and level translator unit converting the A/B pulse into standard pulse with standard shape and level, a subdivider and orientation recognizer unit refining the standard pulse and recognizing the moving orientation, an analog converter unit converting the refined standard pulse into analogue signal that reflects the displacement of the moving component. The standard signal outputted by the signal generator and the converted analogue signal are inputted into a subtracter as the minuend and subtrahend respectively. The output of the subtracter is inputted into the power amplifier and then into the vibration exciter as a driving signal.

Abstract: This invention relates to a monolithic folded F-P cavity used for semiconductor laser, which is composed of a monolithic optical element. The monolithic optical element is made of the material having low propagation loss for a certain spectrum range. Light entering through an input/output coupling surface of the monolithic optical element is reflected several times between the input/output coupling surface and at least two high reflection surfaces within the monolithic optical element, and then at least one part of the light exits through the input/output coupling surface along the path which is collinear with the incident light but in an opposite direction. By means of integrating reflecting and coupling parts of the folded F-P cavity within a single monolithic optical material, this invention greatly improves the reliability of the F-P cavity, and has other advantages, such as insensitive to outside interferences, smaller size, simpler structure and easy usage.

Abstract: A cylindrical model eye comprises a plano-cylindrical portion having a plano surface and a first cylindrical surface opposite to the plano surface, a sphero-cylindrical portion having a convex spherical surface and a second cylindrical surface opposite to the convex spherical surface. The second cylindrical surface mates with the first cylindrical surface, and the first cylindrical surface has substantially the same radius curvature radius as the second cylindrical surface.