Based on the theory of forest growth and the primal investigation data, three formulas of forest basal area growth rate, the Meyer, the Pressler and the Angle, have been studied farther on their nature in this paper.

Calculation of random angle of level symmetry antenna by moment method;

Also, the relation between the electric character and the angles are analyzed.

The method of moments is used to analyze and calculate the broadband characters of impedance,voltage satanding wave ratio(VSWR),gain and radiation pattern of larger angle LPDA,and the relation between these characters and the parameter of antenna construction is discussed in this paper.

The present paper presents a new method for restraining the light lasing of the travelling-wave optical amplifier by means of the combination of dip and taper angles in the structure of the device.

It was found that the opening angle and residual strains of the asthma rat trachea cut at the cartilaginous region was significantly larger than those of the normal rat.

Results in this paper show that for the no-load ring of rat trachea, the opening angle obtained for cartilaginous cut differs from that for muscular cut, i.

The former was trained on treadmill in the light of Bedford rat endurance training model,and 16 weeks later,the rats were decapitated and their thoracic aortas were taken out and used to test the opening angle,wall thickness(WT), internal diameter(ID)and the ratio of WT and ID with a computer picture collection and analysis system.