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Measurements of the dislocation density are compared with locally resolved measurements of carrier lifetime for p-type multicrystalline silicon. A correlation between dislocation density and carrier recombination was found: high carrier lifetimes (> 100 mu s) were only measured in areas with low dislocation density (< 10(5)cm(-2)), in areas of high dislocation density (> 10(6) cm(-2)) relatively low lifetimes (< 20 mu s) were observed. In order to remove mobile impurities from the silicon, a phosphorus diffusion gettering process was applied. An increase of the carrier lifetime by about a factor of three was observed in lowly dislocated regions whereas in highly dislocated areas no gettering efficiency was observed. To test the effectiveness of the gettering in a solar cell manufacturing process, five different multicrystalline silicon materials from four manufacturers were phosphorus gettered. Base resistivity varied between 0.5 and 5 Omega cm for the boron- and gallium-doped p-type wafers which were used in this study. The high-efficiency solar cell structure, which has led to the highest conversion efficiencies of multicrystalline silicon solar cells to date, was used to fabricate numerous solar cells with aperture areas of 1 and 4 cm(2). Efficiencies in the 20% range were achieved for all materials with an average value of 18%. Best efficiencies for 1 cm(2) (20.3%) and 4cm(2) (19.8%) cells were achieved on 0.6 and 1.5 Omega cm, respectively. This proves that multicrystalline silicon of very different material specification can yield very high efficiencies if an appropriate cell process is applied.

UNLABELLED OBJECTIVES : A non-invasive immobilization system consisting of a thermoplastic mask with image-guidance using cone-beam CT (CBCT) and infrared (IR) tracking has been developed to ensure minimal inter- and intra-fractional movement during Gamma Knife radiosurgery. Prior to clinical use for patients on a Gamma Knife, this study clinically evaluates the accuracy and stability of this novel immobilization system with image-guidance in patients treated with standard fractionated radiation therapy on a linear accelerator. MATERIALS & METHODS This prospective cohort study evaluated adult patients planned for fractionated brain radiotherapy. Patients were immobilized with a thermoplastic mask (with the nose cut out) and customized head cushion. A reflective marker was placed on the patient's nose tip and tracked with a stereoscopic IR camera throughout treatment. For each fraction, a pre-treatment, verification (after any translational correction for inter-fraction set-up variation), and post-treatment CBCT was acquired to evaluate inter- and intra-fraction movement of the target and nose. Intra-fraction motion of the nose tip measured on CBCT and IR tracking were compared. RESULTS : Corresponding data from 123 CBCT and IR datasets from six patients are summarized. The mean ± standard deviation (SD) intra-fraction motion of the nose tip was 0.41±0.36 mm based on pre- and post-treatment CBCT data compared with 0.56±0.51 mm using IR tracking. The maximum intra-fraction motion of the nose tip was 1.7 mm using CBCT and 3.2 mm using IR tracking. The mean ± SD intra-fraction motion of the target was 0.34±0.25 mm, and the maximum intra-fraction motion was 1.5 mm. CONCLUSIONS This initial clinical evaluation of the thermoplastic mask immobilization system using both IR tracking and CBCT demonstrate that mean intra-fraction motion of the nose and target is small. The presence of isolated measures of larger intra-fraction motion supports the need for image-guidance and intra-fraction motion management when using this mask-based immobilization system for radiosurgery.

In this article authors considered the problems of organization and implementation of competence-based education process in the preparation of bachelors of vocational training in vocational pedagogical University. Authors analyzed the variable component of the competence-based approach - the competence-oriented approach. Consider the objectives and tasks of the competence-oriented approach. The article highlights the features of the implementation of the competence-oriented approach. The ways of solving of organization and implementation of competence-based approach in vocational pedagogical University are also discussing. Авторами рассмотрены проблемы организации и внедрения компетентностно-ориентированного образовательного процесса при подготовке бакалавров профессионального обучения в профессионально-педагогическом вузе. Проанализирована вариативная составляющая компетентностного подхода – компетентностно-ориентированный подход. Рассмотрены цели и задачи компетентностно-ориентированного подхода. В статье выделены особенности реализации компетентностно-ориентированного подхода. Предложены пути решения организации и внедрения компетентностно-ориентированного подхода в профессионально-педагогический вуз.