The Influence of ITO Dopant Density on J-V Characteristics of Silicon Heterojunction Solar Cells: Experiments and Simulations

The TCO/a-Si:H(p) contact is a critical part of the silicon heterojunction solar cell. At this point, holes from the emitter have to recombine loss free with electrons from the TCO. Since tunneling is believed to be the dominant transport mechanism, a high dopant density in both adjacent layers is critical. In contrast to this, it has been reported that high TCO dopant density can reduce field effect passivation induced by the a-Si:H(p) layer. Thus, in this publication, we systematically investigate the influence of a thin (∼10 nm) ITO contact layer with dopant densities ranging from Nd = 1019 - 1021 cm-3 placed between an ITO bulk layer of 70 nm with Nd= 2·1020 cm-3 and the a-Si:H(p) emitter on the J-V characteristics, with the aim to find an optimum Nd. We accompanied our experiments by AFORS-HET simulations, considering trap-assisted tunneling and field dependent mobilities in the a-Si:H(p) layer. As expected, two regimes are visible: For low Nd the devices are limited by inefficient tunneling, resulting in S-shaped J-V characteristics. For high Nd a reduction of the field effect passivation becomes visible in the low injection range. We can qualitatively reproduce these findings using device simulations

Classes of depression symptom trajectories in patients with major depression receiving a collaborative care intervention

Purpose Collaborative care is effective in improving symptoms of patients with depression. The aims of this study were to characterize symptom trajectories in patients with major depression during one year of collaborative care and to explore associations between baseline characteristics and symptom trajectories. Methods We conducted a cluster-randomized controlled trial in primary care. The collaborative care intervention comprised case management and behavioral activation. We used the Patient Health Questionnaire-9 (PHQ-9) to assess symptom severity as the primary outcome. Statistical analyses comprised latent growth mixture modeling and a hierarchical binary logistic regression model. Results We included 74 practices and 626 patients (310 intervention and 316 control recipients) at baseline. Based on a minimum of 12 measurement points for each intervention recipient, we identified two latent trajectories, which we labeled \u27fast improvers\u27 (60.5%) and \u27slow improvers\u27 (39.5%). At all measurements after baseline, \u27fast improvers\u27 presented higher PHQ mean values than \u27slow improvers\u27. At baseline, \u27fast improvers\u27 presented fewer physical conditions, higher health-related quality of life, and had made fewer suicide attempts in their history. Conclusions A notable proportion of 39.5% of patients improved only \u27slowly\u27 and probably needed more intense treatment. The third follow-up in month two could well be a sensible time to adjust treatment to support \u27slow improvers\u27. (DIPF/Orig.

Coulomb dissociation of O-16 into He-4 and C-12

We measured the Coulomb dissociation of O-16 into He-4 and C-12 within the FAIR Phase-0 program at GSI Helmholtzzentrum fur Schwerionenforschung Darmstadt, Germany. From this we will extract the photon dissociation cross section O-16(alpha,gamma)C-12, which is the time reversed reaction to C-12(alpha,gamma)O-16. With this indirect method, we aim to improve on the accuracy of the experimental data at lower energies than measured so far. The expected low cross section for the Coulomb dissociation reaction and close magnetic rigidity of beam and fragments demand a high precision measurement. Hence, new detector systems were built and radical changes to the (RB)-B-3 setup were necessary to cope with the high-intensity O-16 beam. All tracking detectors were designed to let the unreacted O-16 ions pass, while detecting the C-12 and He-4

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Classes of depression symptom trajectories in patients with major depression receiving a collaborative care intervention

Purpose Collaborative care is effective in improving symptoms of patients with depression. The aims of this study were to characterize symptom trajectories in patients with major depression during one year of collaborative care and to explore associations between baseline characteristics and symptom trajectories. Methods We conducted a cluster-randomized controlled trial in primary care. The collaborative care intervention comprised case management and behavioral activation. We used the Patient Health Questionnaire-9 (PHQ-9) to assess symptom severity as the primary outcome. Statistical analyses comprised latent growth mixture modeling and a hierarchical binary logistic regression model. Results We included 74 practices and 626 patients (310 intervention and 316 control recipients) at baseline. Based on a minimum of 12 measurement points for each intervention recipient, we identified two latent trajectories, which we labeled \u27fast improvers\u27 (60.5%) and \u27slow improvers\u27 (39.5%). At all measurements after baseline, \u27fast improvers\u27 presented higher PHQ mean values than \u27slow improvers\u27. At baseline, \u27fast improvers\u27 presented fewer physical conditions, higher health-related quality of life, and had made fewer suicide attempts in their history. Conclusions A notable proportion of 39.5% of patients improved only \u27slowly\u27 and probably needed more intense treatment. The third follow-up in month two could well be a sensible time to adjust treatment to support \u27slow improvers\u27. (DIPF/Orig.

Foam accumulators: packaging and weight reduction for mobile applications

Standardized parts like hydraulic accumulators are used in nearly every hydraulic system, in many cases even several. Therefore, even small changes in size and weight of accumulators can save considerable material costs. In mobile applications, hydraulic accumulators are used among others in hydro-pneumatic suspension systems. There is a strong focus on miniaturization and weight reduction, as the components always have to be transported with the vehicle. Energy density and energy content of conventional hydraulic accumulators cannot be maximized at the same time. This limitation can be overcome by adding a heat capacity with large surface into the gas volume of the accumulator. The heat capacity enlarges the isothermal frequency range and therefore enlarges the energy density of the accumulator at the given frequency and the given size. In this paper an experimental comparison of conventional hydraulic accumulators and accumulators with foam inserts shows, that at a specific frequency band, the stiffness of foam filled accumulators is significantly lower than of conventional accumulators. The energy density is about 11 % higher than in conventional accumulators. Consequently, a space reduction of about 18 % is possible