The n-type silicon integrated-back contact（IBC） solar cell has attracted much attention due to its high efficiency,whereas its performance is very sensitive to the wafer of low quality or the contamination during hi...The n-type silicon integrated-back contact（IBC） solar cell has attracted much attention due to its high efficiency,whereas its performance is very sensitive to the wafer of low quality or the contamination during high temperature fabrication processing, which leads to low bulk lifetime τbulk. In order to clarify the influence of bulk lifetime on cell characteristics, two-dimensional（2D） TCAD simulation, combined with our experimental data, is used to simulate the cell performances, with the wafer thickness scaled down under various τbulk conditions. The modeling results show that for the IBC solar cell with high τbulk,（such as 1 ms-2 ms）, its open-circuit voltage V oc almost remains unchanged, and the short-circuit current density J sc monotonically decreases as the wafer thickness scales down. In comparison, for the solar cell with low τbulk（for instance, 〈 500 μs） wafer or the wafer contaminated during device processing, the V oc increases monotonically but the J sc first increases to a maximum value and then drops off as the wafer＇s thickness decreases. A model combing the light absorption and the minority carrier diffusion is used to explain this phenomenon. The research results show that for the wafer with thinner thickness and high bulk lifetime, the good light trapping technology must be developed to offset the decrease in J sc.展开更多
Background: Osteotomy wafers were routinely used in orthognathic surgery for repositioning the mobilized maxilla to achieve the planned final occlusion. Objectives: The aim of the current study was to determine compar...Background: Osteotomy wafers were routinely used in orthognathic surgery for repositioning the mobilized maxilla to achieve the planned final occlusion. Objectives: The aim of the current study was to determine comparison of thick and thin intermediate wafer in maxillary Le Fort I osteotomies. Methods: This study was done in 9 patients who had maxillary prognathism or retrognathism abnormality. The maxillary cast was oriented using articulator after facebow transfer. Then photographic and cephalometric data was used to determine proper dental arch segments. All 9 patients had Le Fort I combined with mandibular sagittal split osteotomies. The Le Fort I surgery was done on lateral, septum and medial sinus of nasal and trigomaxillary. The cast was removed from the base articulator and think and thick wafers were fabricated for each. Then the wafers were fixed in 1, 2 and 3 mm anterior (A1, A2 and A3, respectively). After mobilization of the maxilla and adequate bone removal, the jaws were held in occlusion with the thin intermediate wafer. The maxilla was then located against the stable part of the facial skeleton above using the yet unoperated mandible as an autorotated guide. Then the superior reposition >1 or Results: According to the results, the superior reposition was higher in thin wafers fixed in A3 > A2 compared to A1. Also, the same result was detected in thick wafers fixed in A3 > A2 compared to A1, respectively. However, there was no significant difference in both thin and thick wafers in each fixed locations. Conclusion: These results suggest thick wafers have acceptable results in maxillary Le Fort I osteotomies.展开更多
基金Project supported by the Chinese Ministry of Science and Technology Projects(Grant Nos.2012AA050304 and Y0GZ124S01)the National Natural Science Foundation of China(Grant Nos.11104319,11274346,51202285,51402347,and 51172268)the Fund of the Solar Energy Action Plan from the Chinese Academy of Sciences(Grant Nos.Y3ZR044001 and Y2YF014001)
文摘The n-type silicon integrated-back contact（IBC） solar cell has attracted much attention due to its high efficiency,whereas its performance is very sensitive to the wafer of low quality or the contamination during high temperature fabrication processing, which leads to low bulk lifetime τbulk. In order to clarify the influence of bulk lifetime on cell characteristics, two-dimensional（2D） TCAD simulation, combined with our experimental data, is used to simulate the cell performances, with the wafer thickness scaled down under various τbulk conditions. The modeling results show that for the IBC solar cell with high τbulk,（such as 1 ms-2 ms）, its open-circuit voltage V oc almost remains unchanged, and the short-circuit current density J sc monotonically decreases as the wafer thickness scales down. In comparison, for the solar cell with low τbulk（for instance, 〈 500 μs） wafer or the wafer contaminated during device processing, the V oc increases monotonically but the J sc first increases to a maximum value and then drops off as the wafer＇s thickness decreases. A model combing the light absorption and the minority carrier diffusion is used to explain this phenomenon. The research results show that for the wafer with thinner thickness and high bulk lifetime, the good light trapping technology must be developed to offset the decrease in J sc.
文摘Background: Osteotomy wafers were routinely used in orthognathic surgery for repositioning the mobilized maxilla to achieve the planned final occlusion. Objectives: The aim of the current study was to determine comparison of thick and thin intermediate wafer in maxillary Le Fort I osteotomies. Methods: This study was done in 9 patients who had maxillary prognathism or retrognathism abnormality. The maxillary cast was oriented using articulator after facebow transfer. Then photographic and cephalometric data was used to determine proper dental arch segments. All 9 patients had Le Fort I combined with mandibular sagittal split osteotomies. The Le Fort I surgery was done on lateral, septum and medial sinus of nasal and trigomaxillary. The cast was removed from the base articulator and think and thick wafers were fabricated for each. Then the wafers were fixed in 1, 2 and 3 mm anterior (A1, A2 and A3, respectively). After mobilization of the maxilla and adequate bone removal, the jaws were held in occlusion with the thin intermediate wafer. The maxilla was then located against the stable part of the facial skeleton above using the yet unoperated mandible as an autorotated guide. Then the superior reposition >1 or Results: According to the results, the superior reposition was higher in thin wafers fixed in A3 > A2 compared to A1. Also, the same result was detected in thick wafers fixed in A3 > A2 compared to A1, respectively. However, there was no significant difference in both thin and thick wafers in each fixed locations. Conclusion: These results suggest thick wafers have acceptable results in maxillary Le Fort I osteotomies.
