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In this study, a robust and pragmatic technique has been developed to experimentally and theoretically evaluate the performance of high-pressure water jet (HPWJ) dynamics in tight formations by use of a new downhole pressurized drilling tool (DPDT). Experimentally, principles and structure of the new DPDT are described, while well-designed tests are conducted to examine the effects of water jet velocity, dwell time, incident angle, and rock type on the rock-breaking volume at pressures higher than 100 MPa. Numerically, the smoothed particle hydrodynamics coupled with the finite element method has been used to quantify the rock-breaking volume as a function of the 1st principal stress under various conditions. The experimentally measured and numerically simulated rock-breaking volumes are in good agreement under the same conditions. As for a marble specimen, there is a rapid increase in rock-breaking volume at nozzle pressures higher than 150 MPa and dwell times shorter than 40 s. The optimal incident angle for the rock-breaking efficiency is found to be 77°. With the same nozzle pressure and dwell time, the rock types can be ranked in terms of rock-breaking volume in the order of marble

Experimental investigations of electrokinetic phenomena of modified polytetrafluoroethylene membranes in the oily sewage from oil field were performed by using the streaming potential method. The zeta potentials of the membranes in the oily waste water are estimated on the basis of Helmholtz—Smoluchowski equation. The experiment and calculation results show that the membranes are charged negatively, whose zeta poten-tials maintain at around -20mV. And the aperture of membranes, the temperature and the filtration flux have little influence on the streaming potentials and the zeta potentials of the membranes．Also the suspended particulates in the oily sewage are charged negatively. The membranes have strong ability to withhold the suspended substance and powerful antipollution competence because of the role of the charges on the mem-branes.

The application of a p+/p configuration in the window layer of hydrogenated amorphous silicon thin film solar cells is simulated and analyzed utilizing an AMPS-1D program. The differences between p+?p?i?n configuration solar cells and p?i?n configuration solar cells are pointed out. The effects of dopant concentration, thickness of p+-layer, contact barrier height and defect density on solar cells are analyzed. Our results indicate that solar cells with a p+?p?i?n configuration have a better performance. The open circuit voltage and short circuit current were improved by increasing the dopant concentration of the p+ layer and lowering the front contact barrier height. The defect density at the p/i interface which exceeds two orders of magnitude in the intrinsic layer will deteriorate the cell property.