The analysis of the dynamic stress intensity factor for the tip of cracks induced by blasting shows that there are its two peak values when a crack crosses a joint because of the effect of the joint.

When the stress is over its peak value point,the rock will be suddenly destroyed and release a large amount of energy,a process that can be analyzed using the catastrophe theory.

Study on 2-D finite difference method on the center of either high anomaly radon fields in view of the character of radon field over sandstone-type uranium provide an algorithm for further research.

Two new methods of range alignment are proposed: one is peak point alignment; another is direct range-alignment.

3) The pollution situation in the Tumen River got peak point in 1995, and presently, such situation has been improved in great scale, due to effective interventions adopted.

The best results were obtained with EAF-fixation, with respect to the highest amount of DNA-Schiff complex at the peak point of the curve, the longest "plateau" region and the smallest scattering of DNA-Schiff amount values along the "plateau".

The only effect of PEG1500 was a dramatic increase of DNA-Schiff amount at the peak point.

The plethysmograph pressure was converted into alveolar pressure by using the thoracic gas volume, and the resistance was determined breath by breath at each peak point of the flow curve.

Theory and numerical simulation equation of gas migration in compressible coalseam with dual-pore have been established.Distribution curves of gas pressure in coalseam and attenuation curves of gas emission out of coal wall or hole have been obtained by computer numerical simulation and similarity theory. There are high gas pressure and pressure gradient in abutment zone of coalseam neighboring workings. Klinkburg effects and stress liberation by coalseam discharging gas make gas flow increase obviously in hole....

Theory and numerical simulation equation of gas migration in compressible coalseam with dual-pore have been established.Distribution curves of gas pressure in coalseam and attenuation curves of gas emission out of coal wall or hole have been obtained by computer numerical simulation and similarity theory. There are high gas pressure and pressure gradient in abutment zone of coalseam neighboring workings. Klinkburg effects and stress liberation by coalseam discharging gas make gas flow increase obviously in hole.

This article discusses the method and principle of the determination of the depth of underground pipe using maximum value point of inclined magnetic field,peak value point of vertical magnetic field component and half extreme value point of horizontal magnetic field.It is pointed out on principle that there are some problems and it is unpractical to use the maximum value point of inclined magnetic field to determine the depth of pipe or cable.Meanvhile the best depth determination method-horizontal magnetic...

This article discusses the method and principle of the determination of the depth of underground pipe using maximum value point of inclined magnetic field,peak value point of vertical magnetic field component and half extreme value point of horizontal magnetic field.It is pointed out on principle that there are some problems and it is unpractical to use the maximum value point of inclined magnetic field to determine the depth of pipe or cable.Meanvhile the best depth determination method-horizontal magnetic field component triangle method has been sieved out on principle and practically.

Transitive dynamic caustic model experiments were carried out with a transparent birefringence material on a dynamic caustic measuring system. The propagation of cracks in man made jointed materials and the effects of a joint to stress waves were investigated, and the general regularity of crack propagation across a joint was gained. The research results show that the direction of its propagation is different from the original one after a crack has crossed a joint and the propagation of a crack is relative...

Transitive dynamic caustic model experiments were carried out with a transparent birefringence material on a dynamic caustic measuring system. The propagation of cracks in man made jointed materials and the effects of a joint to stress waves were investigated, and the general regularity of crack propagation across a joint was gained. The research results show that the direction of its propagation is different from the original one after a crack has crossed a joint and the propagation of a crack is relative to the angle between the slotted cartridge and the joint and the distance between the bore hole and the joint. The analysis of the dynamic stress intensity factor for the tip of cracks induced by blasting shows that there are its two peak values when a crack crosses a joint because of the effect of the joint.