Water Soluble Aluminum Paste Using Polyvinyl Alcohol for Silicon Solar Cells

Screen-printing aluminum is still dominantly used in the solar cell fabrication process. Ethyl cellulose is one of the main contents of screen-printing pastes that require dichloromethane for its cleaning process, a substance renowned for being extremely toxic and threatening to the human body. Developing environmental friendly aluminum pastes is essential in order to provide an alternative to the commercial pastes. In this work, new, nontoxic polyvinyl alcohol-based aluminum pastes are introduced. Polyvinyl alcohol was used as a soluble polymer that can be synthesized without saponification and that is also soluble in water. Three different pastes were developed using different recipes including many aluminum particle sizes varying from 3.0 to 45 μm, aluminum oxide with particle sizes between 35 and 50 μm, and acetic acid. Evaluation of the pastes was carried out by Scanning Electron Microscope (SEM) image analysis, sheet resistance measurements, and fabricating silicon solar cells using each paste. Solar cells with 15.6% efficiency were fabricated by nonvacuum processing on CZ-Si p-type wafers using developed aluminum pastes on the back side

Survival related to lymph node involvement in lung cancer after sleeve lobectomy compared with pneumonectomy

AbstractObjective: The purpose of this study was to compare the outcomes after sleeve lobectomy and pneumonectomy for patients with non–small cell lung cancer distributed according to their nodal involvement status. Methods: Of 1172 patients in whom primary non–small cell lung carcinoma, including mediastinal lymph nodes, was completely excised, 151 patients underwent sleeve lobectomy and 60 underwent pneumonectomy. For bias reduction in comparison with a nonrandomized control group, we paired 60 patients undergoing sleeve lobectomy with 60 patients undergoing pneumonectomy by using the nearest available matching method. Results: The 30-day postoperative mortality was 2% (1/60) in the pneumonectomy group and 0% in the sleeve lobectomy group. Postoperative complications occurred in 13% of patients in the sleeve lobectomy group and in 22% of those in the pneumonectomy group. Local recurrences occurred in 8% of patients in the sleeve lobectomy group and in 10% of those in the pneumonectomy group. The overall 5- and 10-year survivals for the sleeve lobectomy group were 48% and 36%, respectively, whereas those for the pneumonectomy group were 28% and 19%, respectively (P = .005). Multivariable analysis showed that the operative procedure, T factor, and N factor were significant independent prognostic factors and revealed that survival after sleeve lobectomy was significantly longer than that after pneumonectomy (P = .03). Conclusions: These data suggest that sleeve lobectomy should be performed instead of pneumonectomy in patients with non–small cell lung cancer regardless of their nodal status whenever complete resection can be achieved because this is a lung-saving procedure with lower postoperative risks and is as curative as pneumonectomy. (J Thorac Cardiovasc Surg 2000;119:814-9