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6 (six) is the natural number following 5 and preceding 7. It is a composite number and the smallest perfect number. In mathematics Six is the smallest positive integer which is neither a square number nor a prime number. It is the second smallest composite number after four, equal to the sum and the product of its three proper divisors (, and ). As such, 6 is the only number that is both the sum and product of three consecutive positive numbers. It is the smallest perfect number, which are numbers that are equal to their aliquot sum, or sum of their proper divisors. It is also the largest of the four all-Harshad numbers (1, 2, 4, and 6). 6 is a pronic number and the only semiprime to be. It is the first discrete biprime (2 × 3) which makes it the first member of the (2 × q) discrete biprime family, where q is a higher prime. All primes above 3 are of the form 6n ± 1 for n ≥ 1. As a perfect number: *6 is related to the Mersenne prime 3, s

Vapor Transport Deposition of Methylammonium Iodide for Perovskite Solar Cells

Christophe Ballif, Cédric Bucher, Léo Duchêne, Quentin Jean-Marie Armand Guesnay, Quentin Thomas Jeangros, Nathanaël Miaz, Björn Niesen, Florent Sahli, Niccolo Salsi, Aymeric Michel Schafflützel

Vapor-based processes are promising options to deposit metal halide perovskite solar cells in an industrial environment due to their ability to deposit uniform layers over large areas in a controlled environment without resorting to the use of (possibly toxic) solvents. In addition, they yield conformal layers on rough substrates, an important aspect in view of producing perovskite/ crystalline silicon tandem solar cells featuring a textured silicon wafer for light management. While the inorganic precursors of the perovskite are well suited for thermal evaporation in high vacuum, the sublimation of the organic ones is more complex to control due to their high vapor pressure. To tackle this issue, we developed a vapor transport deposition chamber for organohalide deposition that physically dissociates the organic vapor evaporation zone from the deposition chamber. Once evaporated, organic vapors, here methylammonium iodide (MAI), are transported to the deposition chamber by a carrier gas through a showerhead, ensuring a spatially homogeneous conversion of PbI2 templates to the perovskite phase. The method enables the production of homogeneous perovskite layers on a textured 6 in. wafer. Furthermore, small-scale methylammonium lead iodide solar cells are also processed to validate the quality of the absorbers produced by this hybrid thermal evaporation/vapor transport deposition process.

2021

Variability of Muscle Synergies in Hand Grasps: Analysis of Intra- and Inter-Session Data

Una Pale

Background. Muscle synergy analysis is an approach to understand the neurophysiological mechanisms behind the hypothesized ability of the Central Nervous System (CNS) to reduce the dimensionality of muscle control. The muscle synergy approach is also used to evaluate motor recovery and the evolution of the patients’ motor performance both in single-session and longitudinal studies. Synergy-based assessments are subject to various sources of variability: natural trial-by-trial variability of performed movements, intrinsic characteristics of subjects that change over time (e.g., recovery, adaptation, exercise, etc.), as well as experimental factors such as different electrode positioning. These sources of variability need to be quantified in order to resolve challenges for the application of muscle synergies in clinical environments. The objective of this study is to analyze the stability and similarity of extracted muscle synergies under the effect of factors that may induce variability, including inter- and intra-session variability within subjects and inter-subject variability differentiation. The analysis was performed using the comprehensive, publicly available hand grasp NinaPro Database, featuring surface electromyography (EMG) measures from two EMG electrode bracelets. Methods. Intra-session, inter-session, and inter-subject synergy stability was analyzed using the following measures: variance accounted for (VAF) and number of synergies (NoS) as measures of reconstruction stability quality and cosine similarity for comparison of spatial composition of extracted synergies. Moreover, an approach based on virtual electrode repositioning was applied to shed light on the influence of electrode position on inter-session synergy similarity. Results. Inter-session synergy similarity was significantly lower with respect to intra-session similarity, both considering coefficient of variation of VAF (approximately 0.2–15% for inter vs. approximately 0.1% to 2.5% for intra, depending on NoS) and coefficient of variation of NoS (approximately 6.5–14.5% for inter vs. approximately 3–3.5% for intra, depending on VAF) as well as synergy similarity (approximately 74–77% for inter vs. approximately 88–94% for intra, depending on the selected VAF). Virtual electrode repositioning revealed that a slightly different electrode position can lower similarity of synergies from the same session and can increase similarity between sessions. Finally, the similarity of inter-subject synergies has no significant difference from the similarity of inter-session synergies (both on average approximately 84–90% depending on selected VAF). Conclusion. Synergy similarity was lower in inter-session conditions with respect to intra-session. This finding should be considered when interpreting results from multi-session assessments. Lastly, electrode positioning might play an important role in the lower similarity of synergies over different sessions.

2020

Pd(II)-catalyzed intramolecular aminopalladation/direct C–H arylation under aerobic conditions: synthesis of pyrrolo[1,2-a]indoles

Jieping Zhu

Heating a DMA/pivalic acid (v/v = 4/1) solution of diversely substituted 6-(phenylamino)hex-2-ynoates in the presence of a catalytic amount of Pd(OAc)2 under oxygen atmosphere afforded pyrrolo[1,2-a]indoles in moderate to good yields. A domino sequence involving intramolecular aminopalladation followed by C-H activation and reductive elimination was proposed to account for the observed bis-cyclization.

Elsevier2013

Variability of Muscle Synergies in Hand Grasps: Analysis of Intra- and Inter-Session Data

Una Pale

2020