Influence of surface potential barrier on escape probability of gradient-doping negative electron affinity (NEA) GaN photocathode was studied. Electron energy distribution and escape probability are calculated and compared with those of uniform-doping GaN photocathode. It shows that gradient-doping NEA GaN photocathode can obtain higher electron escape probability. And barrier I has an evident influence on escape probability while barrier Ⅱ has limited influence. Photocurrents of two GaN photocathodes are measured with a multi-information-test system. Experimental results show that gradient-doping GaN photocathode has higher escape probability. Obvious effect on escape probability can be found by barrier I from Cs-activation while barrier Ⅱ from Cs/O-joint-activation has little impact.

To improve resolution of a low-light image intensifier,simulation of electronic transport in a micro-channel plate(MCP) is made.Field distribution is obtained by calculating electron optics with numerical method.Distribution of photoelectron on fluorescent screen is determined by tracing electron trajectory in MCP.Influence of MCP tilt angle,channel diameter,voltage on electronic transport and resolution of image intensifier are studied.It shows that MCP has good electronic transport characteristics,image intensifier has good modulation transfer function(MTF) and high resolution at a title angle of 14°,channel diameter of 5.0 μm,a voltage of 900 V.

The explicit finite difference method is used to the quenching of CrNi steel, the relationship between surface heat transfer coefficients and temperature is determinated by means of solving the inverse problem of heat conduct equation.

By using Linearization method in little time interval, from the heat conduition equation with the 1st-order phasetransformations, the foundation equations of Finite Elememts in solidifications of Metals is established in the paper. The numerical analog on symetric problem in solidification of a grayiron in sandform is obtained by means of triangular element, and the results tallies the corresponding test well.

In this paper, Norsette Method is used to solve the non-steady heat conduction problem. This method prevents the "oscillation" of numerical solution effectively.