The lithium thioindate(LiInS_2) crystal is an attractive material,which can be widely used for nonlinear optical frequency conversion in the infrared region.

The theoretical calculation of frequency conversion in a new bismuth triborate (BiB3O6) crystal with high nonlinear optical (NLO) coefficient is present.

This paper presents a new type of low noise frequency conversion circuit based on the research of phase noise conception, generation as well as relativity measurement method.

The relationship of surface active site and turnover frequency versus activity for ammonia synthesis catalyst which were obtained from different iron oxide as precursor were investigated by means of a physisorption of N 2 and a chemisorption of CO and CO 2 and activity test.

Design of impedance transforming-network by frequency transformation;

The Research and Realization of AD Frequency Transformation Based on DSP;

Diode is one of the nonlinear elements which are usually used in electronic circuit,whose speciality of frequency transformation is widely used in communication system.

Adjusting the switching frequency at which the signal is time-division transferred, the basic frequency signal is transferred through n branches within one signal cycle efficiently, and each branch works for a fixed 1/n of the signal period.

In this paper,first of all,we study the stabilization of the switched linear systems composed of stable subsystems by means of the switching frequency.

The paper discusses refresh rate and frame-changing frequency of LED display screen; according to Ferry-Porter rule, and our experience, the refreshing rate of full color display screen should not be less than 240Hz, for that of brightness over 4000 cd/ m 2 , it must be more than 400Hz.