cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Enhancing User Behavior Sequence Modeling by Generative Tasks for Session Search
Creators: name: Chen, Haonan
name: Dou, Zhicheng
name: Zhu, Yutao
name: Cao, Zhao
name: Cheng, Xiaohua
name: Wen, Ji-Rong
Publisher: name: arXiv
Year: 2022
Subjects: subject: Information Retrieval (cs.IR)
subject: FOS: Computer and information sciences

description: Users' search tasks have become increasingly complicated, requiring multiple queries and interactions with the results. Recent studies have demonstrated that modeling the historical user behaviors in a session can help understand the current search intent. Existing context-aware ranking models primarily encode the current session sequence (from the first behavior to the current query) and compute the ranking score using the high-level representations. However, there is usually some noise in the current session sequence (useless behaviors for inferring the search intent) that may affect the quality of the encoded representations. To help the encoding of the current user behavior sequence, we propose to use a decoder and the information of future sequences and a supplemental query. Specifically, we design three generative tasks that can help the encoder to infer the actual search intent: (1) predicting future queries, (2) predicting future clicked documents, and (3) predicting a supplemental query. We jointly learn the ranking task with these generative tasks using an encoder-decoder structured approach. Extensive experiments on two public search logs demonstrate that our model outperforms all existing baselines, and the designed generative tasks can actually help the ranking task. Besides, additional experiments also show that our approach can be easily applied to various Transformer-based encoder-decoder models and improve their performance.
Study on Laser Parameters for Silicon Solar Cells with LCP Selective Emitters
Creators: name: Hopman, S.
name: Fell, A.
name: Mayer, K.
name: Fleischmann, C.
name: Drew, K.
name: Kray, D.
name: Granek, F.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Wafer-based Silicon Solar Cells and Materials Technology
Mono- and Multicrystalline Silicon Materials and Cells

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 1072-1076
description: In this paper Laser Chemical Processing (LCP) is used for high local doping of selective emitters. In
order to find influencing laser parameters on LCP selective emitters, high-efficiency Si solar cells with size of
2x2 cm2 cells were processed. The highly doped emitters were processed with different laser powers to see the
influence on grooving form and pulse energies. In order to find out if there is a contact resistance problem because of
an isolating PSG layer, solar cells with and without PSG etch after the LCP selective emitter formation were
compared. Laser induced damage is investigated for low and high pulse energies with TEM. This shows no
dislocations for low laser power and small regions of dislocations for high laser power.
Mass Production of New High Efficiency Multicrystalline Silicon Solar Cell Technology with Selective Emitter
Creators: name: Shi, Z.
name: Wenham, S.
name: Ji, J.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Wafer-based Silicon Solar Cells and Materials Technology
Manufacturing Issues

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 1090-1093
description: Mass production of the new high efficiency PLUTO technology with selective emitter has recently
commenced. The first commercial sales of the product commenced in mid 2009. The corresponding PLUTO modules
are believed to be the most efficient multicrystalline silicon photovoltaic modules world-wide. More than 200MW of
new production capacity are currently being implemented and will be completed during 2009. The PLUTO solar cell
technology was developed specifically for lower quality lower cost multicrystalline silicon wafers for consistency
with the industry trend towards this type of wafer. It retains the majority of the fabrication processes in common with
conventional screen-printing technology, making it relatively simple to retrofit onto existing screen-printed
production lines. Importantly however, the Pluto technology was developed to overcome the fundamental
performance limitations of standard screen-printing approaches through achieving narrow metal lines (typically 30
microns wide making them only about 25% of the width of standard screen-printed lines), low metal/silicon interface
area, selective emitter and well passivated surfaces. Two months of full production on juxtaposed 30MWatt
production lines for the two technologies shows that the Pluto technology has a 12-13% performance advantage over
screen-printing technology while the production costs for the two technologies are the same per unit area.
Efficiencies in the range of 17-17.5% in large scale production have been routinely achieved during the first two
months of operation for standard commercial multicrystalline silicon material, with 17.2% efficiency independently
confirmed by the Fraunhoffer Institute. A production capacity of more than 500MW for the Pluto cells is expected to
be implemented by the end of 2010. This is the first publication of the commercialization of this high efficiency
solar cell technology for multicrystalline silicon wafers.
Superhumps in the cataclysmic variable BG Tri
Creators: name: Stefanov, S. Y.
name: Latev, G.
name: Boeva, S.
name: Moyseev, M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present a detailed photometric study of the bright cataclysmic variable BG Tri using ground-based observations mainly from Rozhen Observatory, ASAS-SN, TESS, and WASP sky surveys. We report the discovery of a negative superhump with P$_{-sh}$ = 0.1515(2) days and a co-existing superorbital variation with P=3.94(53) days in data from 2019 and 2020. A positive superhump with P$_{+sh}$ = 0.1727(14) days is also discovered in data from 2006. The obtained negative superhump deficit $\varepsilon_{-}$=0.044(1) and the positive superhump excess $\varepsilon_+$=0.090(9) give us an independent photometric evaluation of the mass ratio (q) of the system, which we find to be q$_-$ = 0.37(2) and q$_+$ = 0.40(5) respectively. We also present a study of the quasi-periodic oscillations (QPOs) and stochastic variability (flickering) in BG Tri. The light curves show a rich mixture of simultaneously overlapping quasi-periods ranging from 5 to 25 minutes. The multi-color (UBVRI) photometric observations from Rozhen Observatory reveal the typical increase of the flickering amplitudes to the shorter wavelengths. The recently introduced A$_{60}$ amplitude of the flickering light source in all studied photometric bands is systematically lower when the negative superhump is gone in season 2021.
description: Accepted 2022 August 15. Received 2022 July 28; in original form 2022 June 17
New Testing Method for Photovoltaic Modules
Creators: name: Vesely, A.
name: Vanek, J.
name: Dolensky, J.
name: Barinka, R.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Components for PV Systems
PV Modules

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 4189-4191
description: This paper described possibilities of fast measuring of whole photovoltaic modules. We focused
particularly on the Electroluminescence measuring method and we compare this method with the others measuring
methods for the Photovoltaic modules and cells.
During the manufacturing of solar cell and panels is possible to make a lot of useful analysis of the quality of
used material and technology processes. Among methods that are displaying distribution of defect in the structure we
can count the electroluminescence which can detect defects in the fastest way. This methods used in manufacture
process is creating large array of data displaying local characteristic of solar cell and panel structure.
VILT: Video Instructions Linking for Complex Tasks
Creators: name: Fischer, Sophie
name: Gemmell, Carlos
name: Mackie, Iain
name: Dalton, Jeffrey
Publisher: name: arXiv
Year: 2022
Subjects: subject: Information Retrieval (cs.IR)
subject: FOS: Computer and information sciences
subject: H.3.3

description: This work addresses challenges in developing conversational assistants that support rich multimodal video interactions to accomplish real-world tasks interactively. We introduce the task of automatically linking instructional videos to task steps as "Video Instructions Linking for Complex Tasks" (VILT). Specifically, we focus on the domain of cooking and empowering users to cook meals interactively with a video-enabled Alexa skill. We create a reusable benchmark with 61 queries from recipe tasks and curate a collection of 2,133 instructional "How-To" cooking videos. Studying VILT with state-of-the-art retrieval methods, we find that dense retrieval with ANCE is the most effective, achieving an NDCG@3 of 0.566 and P@1 of 0.644. We also conduct a user study that measures the effect of incorporating videos in a real-world task setting, where 10 participants perform several cooking tasks with varying multimodal experimental conditions using a state-of-the-art Alexa TaskBot system. The users interacting with manually linked videos said they learned something new 64% of the time, which is a 9% increase compared to the automatically linked videos (55%), indicating that linked video relevance is important for task learning.
description: 7 pages, IMuR Preprint
Silicon Nitride Films Deposited by Atmospheric Pressure Mircowave PECVD
Creators: name: Dresler, B.
name: Roch, J.
name: Leupolt, B.
name: Dani, I.
name: Hopfe, V.
name: Heintze, M.
name: Möller, R.
Publisher: name: WIP-Munich
Year: 2008
Subjects: Wafer-Based Silicon Solar Cells and Materials Technology
Mono- and Multicrystalline Silicon Cells and Materials, Processing Technology of

description: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 1900-1903
description: In standard production technology of crystalline silicon solar cells the deposition of an antireflective and passivating silicon nitride (SiN) layer is carried out by plasma enhanced chemical vapor deposition under vacuum. The combination of an atmospheric pressure deposition process with a similar etching technology in an advanced in-line process sequence could provide significant potential for cost saving. Deposition of silicon nitride by atmospheric pressure microwave PECVD was studied on silicon solar wafers. The plasma source, based on the concept of a cylindrical resonator with annular slots (CYRANNUS®), operates at a
frequency of 2.45 GHz with a working with of 156 mm. SiNx:H films were deposited on mono- and multi-crystalline 6” Si wafers by using the metal-organic precursor tetramethylsilane (Si(CH3)4, TMS) or silane (SiH4) and ammonia
as precursors. The layers were characterized by FTIR spectroscopy, spectro-ellipsometry, and microwave-induced photo conductance decay.
On Augmented Kohn-Sham Potential for Energy as a Simple Sum of Orbital Energies
Creators: name: Levy, Mel
name: Zahariev, Federico
Publisher: name: arXiv
Year: 2016
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: It has recently been observed [Phys. Rev. Lett. 113, 113002 (2014)] that the ground-state energy may be obtained directly as a simple sum of augmented Kohn-Sham orbital energies, where it was ascertained that the corresponding one-body shifted Kohn-Sham effective potential has appealing features. With this in mind, eigenvalue and virial constraints are deduced for approximating this potential.
description: 5 pages
Characterization of Si Solar Cells Imperfections in the Near-Field
Creators: name: Skarvada, P.
name: Tomanek, P.
name: Macku, R.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Advanced Photovoltaics: New Concepts and Ultra-high Efficiency
Fundamental Studies

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 351-354
description: This paper deals with microscale localization of solar cell imperfections. Imperfections are areas on the
solar cell that emits light in visible range when the cell is reverse-biased. Samples under investigation are
monocrystalline silicon solar cells. Local topography, near-field optical beam induced current, local optical properties
and local visible light emission using high resolution and high sensitive techniques together with light emission
thermal dependence have been measured. Generally light emission occurs in places where the near-field optical beam
induced current has its local minima. The results when there is no evident correlation between light emission and
near-field optical beam induced current are presented in this paper. It was found that one light emission macroscopic
spot can consist of several small light emission spots which diameters are less than 8 μm.
Identifying Differences in Diagnostic Skills between Physics Students: Students' Self-Diagnostic Performance Given Alternative Scaffolding
Creators: name: Cohen, Elisheva
name: Mason, Andrew
name: Singh, Chandralekha
name: Yerushalmi, Edit
Publisher: name: arXiv
Year: 2016
Subjects: subject: Physics Education (physics.ed-ph)
subject: FOS: Physical sciences

description: "Self-diagnosis tasks" aim at fostering diagnostic behavior by explicitly requiring students to present diagnosis as part of the activity of reviewing their problem solutions. We have been investigating the extent to which introductory physics students can diagnose their own mistakes when explicitly asked to do so with different levels of scaffolding support provided to them. In our study in an introductory physics class with more than 200 students, the recitation classes were split into three different experimental groups in which different levels of guidance were provided for performing the self-diagnosis activities. We present our findings that students' performance was far from perfect. However, differences in the scaffolding in the three experimental groups (i.e. providing a correct solution and a self-diagnosis rubric) noticeably affected the resulting diagnosis.
description: 4 pages, 8 tables, conference proceedings. Please see companion paper in 2008 Physics Education Research Conference (Vol. 1064, No. 1, pp. 147-150), AIP Publishing. Also see set of two manuscripts: Physical Review Special Topics-Physics Education Research, 8(2), 020109 and 020110 (2012). In 2008 Physics Education Research Conference (Vol. 1064, No. 1, pp. 99-102). AIP Publishing (2008)
Investigating a New Approach to Market Change Measurement in Public Transport
Creators: name: Blake, Prudence
Publisher: name: Monash University
Year: 2021
Subjects: Transport engineering
Marketing theory

description: The development and exploration of a new concept for market change measurement termed ‘Customer Fluctuation’. The approach is based on the theory of ‘customer churn’, which measures ongoing users against those exiting a market. Customer fluctuation builds on this approach by measuring not only the relationship between lost and continuing users but also users that are new or returning to public transport use. This thesis measures customer fluctuation using two different data approaches; smart card data and a survey. Comparisons are made between the two approaches and further improvements are recommended.
Definition of the Euro Efficiency of Solar Modules
Creators: name: Te Heesen, H.
name: Baron, M.
name: Kurz, C.
name: Pfatischer, R.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Components for PV Systems
PV Modules

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 4154-4155
description: The Euro-eta or Euro efficiency [1] is a main performance criterion for inverters. A comparable ratio
for solar modules has not been established yet. Litzenburger has suggested a first definition of a Euro-eta value for
modules [2] taking the solar irradiance into account. We have enhanced his idea to determine the performance of PV
modules depending both on irradiance and module temperature. We present a first suggestion for a weight matrix to
calculate the Euro-eta of solar modules taking irradiance as well as temperature effects into account. We have validated
our definition by analyzing monitoring data of PV plants to verify our matrix. The Euro-eta definition will be useful e. g.
for cost comparisons of solar modules. Currently, the performance of inverters can be compared directly using the Euroeta.
Thus, different cost models can be set up based on the Euro-eta value. Furthermore, the Euro efficiency definition
allows an independent comparison of the performance of solar modules.
Chemical abundances and kinematics of barium stars
Creators: name: de Castro, D. B.
name: Pereira, C. B.
name: Roig, F.
name: Jilinski, E.
name: Drake, N. A.
name: Chavero, C.
name: Silva, J. V. Sales
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: In this paper we present an homogeneous analysis of photospheric abundances based on high-resolution spectroscopy of a sample of 182 barium stars and candidates. We determined atmospheric parameters, spectroscopic distances, stellar masses, ages, luminosities and scale height, radial velocities, abundances of the Na, Al, $alpha$-elements, iron-peak elements, and s-process elements Y, Zr, La, Ce, and Nd. We employed the local-thermodynamic-equilibrium model atmospheres of Kurucz and the spectral analysis code {\sc moog}. We found that the metallicities, the temperatures and the surface gravities for barium stars can not be represented by a single gaussian distribution. The abundances of $alpha$-elements and iron peak elements are similar to those of field giants with the same metallicity. Sodium presents some degree of enrichment in more evolved stars that could be attributed to the NeNa cycle. As expected, the barium stars show overabundance of the elements created by the s-process. By measuring the mean heavy-element abundance pattern as given by the ratio [s/Fe], we found that the barium stars present several degrees of enrichment. We also obtained the [hs/ls] ratio by measuring the photospheric abundances of the Ba-peak and the Zr-peak elements. Our results indicated that the [s/Fe] and the [hs/ls] ratios are strongly anti-correlated with the metallicity. Our kinematical analysis showed that 90% of the barium stars belong to the thin disk population. Based on their luminosities, none of the barium stars are luminous enough to be an AGB star, nor to become self-enriched in the s-process elements. Finally, we determined that the barium stars also follow an age-metallicity relation.
description: 30 pages, 26 figures, 18 tables, accepted for publication in MNRAS
Laser Structuring for Monolithic Series Connection of Organic Thin-Film Solar Cells
Creators: name: Schoonderbeek, A.
name: Bärenklau, M.
name: Rösch, R.
name: Teckhaus, D.
name: Muhsin, B.
name: Haupt, O.
name: Hoppe, H.
name: Stute, U.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Advanced Photovoltaics: New Concepts and Ultra-high Efficiency
Organic-based PV

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 319-324
description: This paper describes the monolithic series connection of organic thin-film solar modules by means of
laser structuring. Experiments are performed with a broad range of laser sources and parameters. The most important
laser parameters in thin film processing are the radiation wavelength, pulse duration, pulse energy and spot-to-spot
overlap. Processing with several wavelengths (e.g. 355 nm, 532 nm, and 1064 nm) and pulse durations in the femto-,
pico- and nanosecond ranges are evaluated. The results obtained with the best suitable laser sources are further
optimized and presented in this paper. The focus of the experiments is to obtain an optimal edge quality without
damaging the substrate or the layer below the structured region. Organic test cells on glass substrates are produced
using the optimized laser structuring process. These are analysed and have an efficiency comparable to cells
structured with methods, commonly used in research laboratories. The presented results, show the applicability of the
technology for future mass production where processing speeds greater than 1m/s are required. Currently available
industrial laser sources are able to achieve these processing speeds, necessary for economically feasible structuring
of organic modules in a roll-to-roll production.
Crystallization of self-propelled hard-discs : a new scenario
Creators: name: Briand, G.
name: Dauchot, O.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We experimentally study the crystallization of a monolayer of vibrated discs with a built-in polar asymmetry, a model system of active liquids, and contrast it with that of vibrated isotropic discs. Increasing the packing fraction $ϕ$, the quasi-continuous crystallization reported for isotropic discs is replaced by a transition, or a crossover towards a "self-melting" crystal. Increasing the packing fraction from the liquid phase, clusters of dense hexagonally-ordered packed discs spontaneously form, melt, split and merge leading to a highly intermittent and heterogeneous dynamics. The resulting steady state cluster size distribution decreases monotonically. For packing fraction larger than $ϕ^*$, a few large clusters span the system size and the cluster size distribution becomes non monotonic, the transition being signed by a power-law. The system is however never dynamically arrested. The clusters permanently melt from place to place forming droplets of active liquid which rapidly propagate across the system. This state of affair remains up to the highest possible packing fraction questioning the stability of the crystal for active discs, unless at ordered close packing.
description: 4 pages, 4 figures, 1 Supp Matt
Numerical and Graphic Method for Calculation of Majority Carrier Compensation of Multiple Doped Semiconductors in Photovoltaics
Creators: name: Wang, G.
name: Liu, J.
name: Zheng, Z.
name: Cheng, Z.
name: Pan, J.
name: Georghiou, G.
name: Chin, K.K.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Advanced Photovoltaics: New Concepts and Ultra-high Efficiency
Fundamental Studies

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 359-363
description: In thin film solar cells, due to production cost concern, the semiconductor materials usually contain
multiple impurity/defect states as donor and acceptor dopants. Local charge neutrality (LCN) condition is proposed to
determine the equilibrium Fermi level and concentration of electrons and holes. A general equation of LCN is
expressed as which is a transcendental equation of EF. It is impossible to find its analytical solution and the equation
can only be solved by using graphic or numerical method. We proposed a simple approximate graphic method (GM)
for estimation of majority carrier compensation of semiconductors with multiple donors and multiple acceptors. By
introducing the concept of ranking of the dopants and wrapping step function, the approximate concentration and
Fermi level could be obtained easily. In this work, we analyse the graphic method and propose a new numericgraphic
method (NGM) based on GM. Comparison of NGM with numerical method (NM) and analytics of accuracy
of GM are made. With the help of numerical calculation, some procedures of GM which allow a wilder rang of
application of GM are improved.
Seventeen New Variable Stars Detected in Vulpecula and Perseus
Creators: name: Furgoni, Riccardo
Publisher: name: arXiv
Year: 2015
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: I report the discovery of seventeen new variable stars in the Northern Sky: three eclipsing (GSC 02129-00759; GSC 02129-00947; GSC 02869-02559), one eruptive (GSC 02856-02521), ten pulsating (2MASS J19305329+2558520; GSC 02129- 00537; 2MASS J19323543+2524000; 2MASS J19263580+2616428; HD 275169; GSC 02869-00313; GSC 02869-01981; GSC 02856-01391; GSC 02860-01552; GSC 02856-01465) and three rotating (one of which is suspected) (GSC 02142-01107; GSC 02856-00169; GSC 02865-01593).
description: 10 pages, 20 figures, 3 tables. arXiv admin note: substantial text overlap with arXiv:1412.4289
Determination of the Emitter Saturation Current Density of Silicon Solar Cells Using Photoluminescence and Quantum Efficiency Analysis
Creators: name: Hinken, D.
name: Bothe, K.
name: Ramspeck, K.
name: Herlufsen, S.
name: Brendel, R.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Wafer-based Silicon Solar Cells and Materials Technology
Mono- and Multicrystalline Silicon Materials and Cells

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 1082-1085
description: We determine the emitter saturation current density J0e of silicon solar cells using a combined approach
of photoluminescence (PL) and quantum efficiency (QE) measurements. We prove that the ratio of two PL
measurements obtained under open circuit and short circuit conditions yields the saturation current density J0. We obtain
the saturation current density contribution of the base J0b from quantum efficiency measurements. The difference
between the total saturation current density J0 and J0b yields the emitter saturation current density. This analysis is
applied to both, a high-efficiency solar cell as well as to a standard industrial solar cell. The benefit of using photoluminescence
is a possible spatially resolved application if combining camera-based PL measurements with mappings
of the effective diffusion length.
Orbital Magnetism of Bloch Electrons I. General Formula
Creators: name: Ogata, Masao
name: Fukuyama, Hidetoshi
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We derive an exact formula of orbital susceptibility expressed in terms of Bloch wave functions, starting from the exact one-line formula by Fukuyama in terms of Green's functions. The obtained formula contains four contributions: (1) Landau-Peierls susceptibility, (2) interband contribution, (3) Fermi surface contribution, and (4) contribution from occupied states. Except for the Landau-Peierls susceptibility, the other three contributions involve the crystal-momentum derivatives of Bloch wave functions. Physical meaning of each term is clarified. The present formula is simplified compared with those obtained previously by Hebborn et al. Based on the formula, it is seen first of all that diamagnetism from core electrons and Van Vleck susceptibility are the only contributions in the atomic limit. The band effects are then studied in terms of linear combination of atomic orbital treating overlap integrals between atomic orbitals as a perturbation and the itinerant feature of Bloch electrons in solids are clarified systematically for the first time.
description: 18 pages, 2 figures
Wave fronts and cascades of soliton interactions in the periodic two dimensional Volterra system
Creators: name: Bury, Rhys
name: Mikhailov, Alexander V.
name: Wang, Jing Ping
Publisher: name: arXiv
Year: 2016
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: In the paper we develop the dressing method for the solution of the two-dimensional periodic Volterra system with a period N. We derive soliton solutions of arbitrary rank $k$ and give a full classification of rank 1 solutions. We have found a new class of exact solutions corresponding to wave fronts which represent smooth interfaces between two nonlinear periodic waves or a periodic wave and a trivial (zero) solution. The wave fronts are non-stationary and they propagate with a constant average velocity. The system also has soliton solutions similar to breathers, which resembles soliton webs in the KP theory. We associate the classification of soliton solutions with the Schubert decomposition of the Grassmanians ${\rm Gr}_{\mathbb{R}}(k,N)$ and ${\rm Gr}_{\mathbb{C}}(k,N)$.
A Provably Efficient Model-Free Posterior Sampling Method for Episodic Reinforcement Learning
Creators: name: Dann, Christoph
name: Mohri, Mehryar
name: Zhang, Tong
name: Zimmert, Julian
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Thompson Sampling is one of the most effective methods for contextual bandits and has been generalized to posterior sampling for certain MDP settings. However, existing posterior sampling methods for reinforcement learning are limited by being model-based or lack worst-case theoretical guarantees beyond linear MDPs. This paper proposes a new model-free formulation of posterior sampling that applies to more general episodic reinforcement learning problems with theoretical guarantees. We introduce novel proof techniques to show that under suitable conditions, the worst-case regret of our posterior sampling method matches the best known results of optimization based methods. In the linear MDP setting with dimension, the regret of our algorithm scales linearly with the dimension as compared to a quadratic dependence of the existing posterior sampling-based exploration algorithms.
Bifacial Thin Solar Cells With Screen Printed Emitters and Metallizations
Creators: name: Recart, F.
name: Hoces, I.
name: Azkona, N.
name: Freire, I.
name: Pérez Manzano, L.
name: Fano, V.
name: Lago, R.
name: Jimeno, J.C.
Publisher: name: WIP-Munich
Year: 2008
Subjects: Wafer-Based Silicon Solar Cells and Materials Technology
Mono- and Multicrystalline Silicon Cells and Materials, Processing Technology of

description: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 1893-1896
description: An in-line process has been developed for manufacturing bifacial cells on thin (130 μm) Czochralski substrates. This small thickness reduces the silicon consumption and helps to minimize the bulk recombination and to
increase the bifaciality when low quality substrates are used. Large area (125x125 mm2) thin silicon solar cells have been manufactured on n-type substrates using this fully industrial process and leading to 100% bifacial BSF cells that show open circuit voltages higher than 600 mV and fill factors better than 75%. A number of issues have been overcome, including the in-line simultaneous diffusion of boron and phosphorus emitters with proper impurity profiles and saturation current densities; the consecution of high bulk lifetimes using commercial screen printed dopant sources, and the successful contact of these emitters using screen printing metallic pastes. This process reduces remarkably the use of silicon per watt (less than 60% of the consumption of actual commercial silicon monocrystalline cells) and improves the output power of the cell due to albedo collection. In addition, this paper analyzes the influence of resistivity and thickness on the performance of BSF bifacial cells, paying attention to their bifaciality and front efficiencies and discussing realistic lifetime issues.
NIR-Spectroscopical Process Control for Wet Chemical Processes
Creators: name: Zimmer, M.
name: Birmann, K.
name: Hilgert, J.
name: Rentsch, J.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Wafer-based Silicon Solar Cells and Materials Technology
Manufacturing Issues

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 1101-1105
description: Crystalline silicon solar cell fabrication requires many wet chemical processes, such as alkaline and
acidic texturisation processes as well as several cleaning procedures. Besides the conventional chemical analysis
techniques like titration and chromatography, near-infrared (NIR) spectroscopy gains more and more importance. In
this paper, the suitability of NIR spectroscopy for the process control in wet chemical processes is compared to
alternative analysis methods like titration, ion chromatography, HPLC and surface tension measurements.
Series Resistance Effects in Back Contact Silicon Solar Cells
Creators: name: Montalbán, C.
name: Varner, K.E.
name: Jimeno, J.C.
name: Gutiérrez, J.R.
name: Gee, J.M.
Publisher: name: WIP-Munich
Year: 2008
Subjects: Wafer-Based Silicon Solar Cells and Materials Technology
Mono- and Multicrystalline Silicon Cells and Materials, Processing Technology of

description: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 1843-1846
description: Back contact solar cells present the capability of a superior photocurrent collection, due to the lack or reduction of the metal shadows on its front face. However the more complex collection and transport of carriers imply an extra ohmic loss, which competes seriously with the advantage of the higher photocurrent. This paper analyzes the effect of the regions above the busbars, what give a relevant and not well studied mechanism of ohmic losses in back contact solar cells.
Approach to Solar Radiation for Obtaining High Resolution LBIC Images
Creators: name: Navas, F.J.
name: Alcántara, R.
name: Fernández-Lorenzo, C.
name: Martín-Calleja, J.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Advanced Photovoltaics: New Concepts and Ultra-high Efficiency
Fundamental Studies

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 337-342
description: This work presents a methodology and instrumental device for obtaining high resolution LBIC maps in
conditions approximating to solar irradiation. The methodology developed is based on a system of trichromatic
irradiation of the device under study. This irradiation system is composed of three lasers which emit in the red, green
and blue regions of the solar spectrum. The methodology establishes the relative irradiation powers using the
emission distribution of Planck’s blackbody, which provides an approximation to solar emissions, and thus, the
system establishes an initial approximation for obtaining high resolution LBIC scans under these conditions. The
methodology includes an algorithm and a procedure capable of forming images from the three scans carried out with
the three lasers, providing information about the quantum efficiency of the photovoltaic devices under solar
irradiation conditions. To check the proposed methodology, LBIC scans are shown which were performed on a
polycrystalline silicon solar cell. Furthermore, the study shows the variability of the device's photoelectric properties,
which depend on the wavelength in the vicinity of grain boundaries.
Impact of Climatic Induced Spectral Changes on Thin Film PV-Module Performance
Creators: name: Rennhofer, M.
name: Berger, K.
name: Wagner, J.E.
name: Leidl, R.
name: Zamini, S.
name: Laube, W.
name: Baumgartner, D.
name: Weihs, P.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Advanced Photovoltaics: New Concepts and Ultra-high Efficiency
Fundamental Studies

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 347-350
description: Within the PV-SPEC project we investigate the performance of different photovoltaic technologies
for various climatic regions of Austria. Especially low land locations (170 m elevation) and high land locations
(1600 m elevation) are investigated. Photovoltaic modules of most differing spectral responses were chosen. The
impact of the inhomogeneous climatic conditions of Austria resulting from the heterogeneous topography is
object of detailed investigation regarding the photovoltaic-module parameters. The results were achieved by
measuring the short-circuit values of the photovoltaic devices of different technologies oriented in different
orientations each. The results show a strong dependence of the short circuit current on changes in the irradiance
spectrum in the plain of the PV-modules induced by the variation of the ambient parameters. Further, the
behavior of the photovoltaic technologies differs a lot for the compared topographic sites.
Effect of Thermal Gradient on Electrical Efficiency of Hybrid PV/T
Creators: name: Tina, G.M.
name: Cosentino, F.
name: Notton, G.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Components for PV Systems
PV Modules

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 4119-4124
description: a temperature gradient over both a PV module and PV array in hybrid thermal/PV system is
inevitable. The temperature distribution among PV cells (modules) produce energy losses, the amount of these
losses depends on many parameters: temperature gradient, number of cells (modules), type of connection (e.g.
series parallel) . The evaluation of the losses can allow to choose a optimal design of the PV/T system.
Photovoltaic Module and Shadow: Study and Integration of a Current Balancing System
Creators: name: Vighetti, S.
name: Lembeye, Y.
name: Ferrieux, J.-P.
name: Barbaroux, J.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Components for PV Systems
PV Modules

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 4139-4143
description: Current crystalline photovoltaic modules (PV) are designed with 36 or 72 series – connected PV
cells. Usually, in order to protect the PV cells, a bypass diode is connected in anti-parallel every 18 PV cells.
Furthermore, the series connection of PV modules is necessary in order to obtain the input voltage for the
converter. Yet, each PV cell has its own current-voltage characteristic. The manufacturers guarantee a dispersion
of 3% of maximum power between solar cells; so series connection of heterogeneous PV cells generates
mismatch losses. Mismatch losses can increase in case of shading which may greatly reduce power output.
Moreover, building integrated PV (BIPV) has seen an important development in urban areas bringing to the light
shadow related problems. This paper proposes a PV module with an integrated power electronics topology able to
replace bypass diodes while extracting maximum power of each 18 PV cell string. The operating principle of the
current balancing system (CBS) is studied with multiple input levels and various PV generator characteristics.
Five different layouts of the CBS are studied using a 144 PV cell string subdivided in 18 cell groups which are
submitted to 21 shade scenarios. Furthermore, the optimal CBS can be implemented easily into current 72 cell
modules. Experimental results on a prototype are compared to simulation results in chosen shade conditions. The
performance analysis carried out shows interest in using the 4 input level CBS rather than traditional bypass
diode modules.
Carrier Confinement and Transport in High Band Gap Materials with Embedded Si Quantum Dots
Creators: name: Löper, P.
name: Hiller, D.
name: Künle, M.
name: Gradmann, R.
name: Rothfelder, M.
name: Janz, S.
name: Hermle, M.
name: Zacharias, M.
name: Glunz, S.W.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Advanced Photovoltaics: New Concepts and Ultra-high Efficiency
New Materials, Cells and Modules

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 269-273
description: Silicon nanocrystals in dielectric matrices are usually produced using plasma enhanced chemical vapour
deposition of Si rich Si-based dielectrics and thermal annealing at high (1100°C) temperatures. In this paper, the
influence of boron doping and hydrogen dilution on the formation of Si and SiC nanocrystals in a SiC film is
investigated. The dark conductivity increases from 5.4·10-8 W-1cm-1 without additional dopant gas to 2.1·10-4 W-1cm-1
with 100 sccm additional B2H6 in H2 for films annealed at 900 °C and further to 1.2·10-3 W-1cm-1 for 1000 °C annealing
and 100 sccm dopant gas mixture. Furthermore, IV-curves in dark and under illumination are presented for a superlattice
of 4nm Si nanocrystals and 4nm SiO2 barrier layers and are compared to those of SiC layers with Si nanocrystals.
Day 4™ Technology for Conceptually New PV Module Production
Creators: name: Bram Sadlik, B.
name: Rubin, L.
name: Nebusov, V.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Components for PV Systems
PV Modules

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 4144-4147
description: Day4™ Energy uses a novel approach for interconnecting PV cells that was introduced into module
mass production in 2006. The cell interconnect is done by laminating a grid of wires between the positive terminal of
one cell and the negative terminal of the next cell, thus replacing the soldered busbar ribbon found on standard cells.
Previous studies have shown that modules manufactured with this method have increased FFs, voltage and current.
However, the real world performance of PV systems, regardless of the technology used is limited by environmental
factors such as low radiation, cloud cover, module temperature and shading. Recently Day4™ Energy launched a
new module with multiple bypass diodes allowing increase energy yields over conventional modules due to a high
tolerance to shade. In this simulation the performance of the module was estimated under a highly idealized situation
relative to a standard module. The simulation shows that under these idealized conditions the area a large field
installation employing these shade tolerant modules can be decrease by ~25% without significant impact to the
annual yield. An equivalent system using conventional modules would suffer a 10% energy yield loss.
Progress Towards a High Efficiency InGaN/Si Hybrid Solar Cell
Creators: name: Gherasoiu, I.
name: Reichertz, L.A.
name: Yu, K.M.
name: Ager III, J.W.
name: Kao, V.M.
name: Walukiewicz, W.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Advanced Photovoltaics: New Concepts and Ultra-high Efficiency
New Materials, Cells and Modules

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 280-283
description: In this paper we report on the proof of principle of III-nitride/silicon tandem solar cell. We have
demonstrated photovoltaic activity in 0.25 cm2 dual junction solar cells, made of p/n GaN junction grown by molecular
beam epitaxy (MBE) on a standard n-type Si wafer with an Al doped p-type surface. An open circuit voltage (Voc) of 2.5
V was measured under 1x sun AM1.5G condition with additional UV laser illumination of the GaN junction. We have
also fabricated InGaN p/n junction with about 20% In content on Si substrates. The diode shows the onset of a
phoresponse at about 2.6 eV. Relatively low shunt and high series resistance are the key factors limiting performance of
the InGaN cells with larger In content.
Towards Quantum Dot Solar Concentrators with Thin Film Solar Cells
Creators: name: Van Sark, W.G.J.H.M.
name: De Mello Donegá, C.
name: Schropp, R.E.I.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Advanced Photovoltaics: New Concepts and Ultra-high Efficiency
New Materials, Cells and Modules

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 289-292
description: Quantum dots are proposed as luminescent species in luminescent solar concentrators in combination
with thin film silicon solar cells. As both tuning absorption and emission properties of quantum dots is possible by
adapting process conditions, as well as tuning the band gap of thin film silicon solar cells, an optimum combination is
expected to exist for which the conversion efficiency of the whole device is maximum. As a first step we have
employed ray-tracing modeling to determine the efficiency of a luminescent concentrator using several quantum dots
and heteronanocrystals with varying Stokes’ shift and absorption cross sections. A maximum efficiency of 5.9% is
found for so-called Type II heteronanocrystals.
Towards 20% Efficient n-Type Silicon Solar Cells With Screen-Printed Aluminium-Alloyed Rear Emitter
Creators: name: Schmiga, C.
name: Hermle, M.
name: Glunz, S.W.
Publisher: name: WIP-Munich
Year: 2008
Subjects: Wafer-Based Silicon Solar Cells and Materials Technology
Mono- and Multicrystalline Silicon Cells and Materials, Processing Technology of

description: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 982-987
description: We present n-type silicon solar cells featuring an effectively passivated full-area screen-printed aluminium-alloyed rear emitter. Two different passivation stacks for Al-p+ emitters are investigated: The first one consists of a plasma-enhanced-chemical-vapour-deposited amorphous silicon film covered by a plasma silicon oxide layer, the second one of a plasma-assisted atomic-layer-deposited aluminium oxide also covered by a plasma silicon oxide. For our a-Si/SiOx-passivated back junction n+np+ solar cells (4 cm2) we achieve an increase in the open-circuit voltage of 15–20 mV compared to the non-passivated emitter cells, for our Al2O3/SiOx-passivated cells the shift amounts to 25–30 mV, resulting in Voc values up to 655 mV. This leads to record-high efficiencies for solar cells with aluminium-doped emitter of 19.5 % and 20.1 %, respectively, on n-type phosphorus-doped 10 Ωcm float-zone silicon material.
Progress Towards a Monolithic Si-SiGe Tandem Solar Cell
Creators: name: Clark, A.
name: Arkun, E.
name: Smith, R.
name: Semans, S.
name: Vosters, G.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Advanced Photovoltaics: New Concepts and Ultra-high Efficiency
New Materials, Cells and Modules

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 293-296
description: In this work material engineering is being used to develop a method for extending the cut off wavelength of a silicon cell. The material of choice is the group IV alloy SixGe1-x. If this were to be placed in direct contact with the silicon cell lattice mismatch and the inherent defects that accompany it would lead to a reduction in the performance of the front silicon cell. What will be shown is that an intermediate layer of rare earth oxide can be used to grade the lattice spacing from Si to the chose composition of, moreover this layer will both electrically and chemically isolate the second cell from the silicon cell. Although this is a non-traditional tandem design requiring modified contacts, the ability to keep the design and performance of the primary silicon cell is advantageous. Results on the development of the oxide layer are presented, along with some initial test data from a SiGe photodiode.