Pois cultivé

thumb|upright|Pois mangetout chinois. Le Pois cultivé (Pisum sativum L.) est une espèce de plante annuelle de la famille des légumineuses (Fabacées), largement cultivée pour ses graines, consommée comme légume ou utilisée comme aliment du bétail. Le terme désigne aussi la graine elle-même, riche en énergie (amidon) et en protéines (de 16 à 40 %). Les pois secs se présentent souvent sous la forme de « pois cassés ». Les pois frais, récoltés avant maturité, sont plus couramment appelés « petits pois ». Le pois est cultivé depuis l'époque néolithique et a accompagné les céréales dans l'apparition de l'agriculture au Proche-Orient. Il était dans l'Antiquité et au Moyen Âge un aliment de base en Europe et dans le bassin méditerranéen. De nos jours, sa culture est pratiquée dans les cinq continents, particulièrement dans les régions de climat tempéré d'Eurasie et d'Amérique du Nord. Le pois sec est un aliment traditionnellement important dans certains pays, notamment le

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Kinetics of xylem loading, membrane potential maintenance, and sensitivity of K+-permeable channels to reactive oxygen species: physiological traits that differentiate salinity tolerance between pea and barley

Amandine Massart

Salt sensitive (pea) and salt tolerant (barley) species were used to understand the physiological basis of differential salinity tolerance in crops. Pea plants were much more efficient in restoring otherwise depolarized membrane potential thereby effectively decreasing K+ efflux through depolarization-activated outward rectifying potassium channels. At the same time, pea root apex was 10-fold more sensitive to physiologically relevant H2O2 concentration and accumulated larger amounts of H2O2 under saline conditions. This resulted in a rapid loss of cell viability in the pea root apex. Barley plants rapidly loaded Na+ into the xylem; this increase was only transient, and xylem and leaf Na+ concentration remained at a steady level for weeks. On the contrary, pea plants restricted xylem Na+ loading during the first few days of treatment but failed to prevent shoot Na+ elevation in the long term. It is concluded that superior salinity tolerance of barley plants compared with pea is conferred by at least three different mechanisms: (1) efficient control of xylem Na+ loading; (2) efficient control of H2O2 accumulation and reduced sensitivity of non-selective cation channels to H2O2 in the root apex; and (3) higher energy saving efficiency, with less ATP spent to maintain membrane potential under saline conditions.

Wiley-Blackwell2014

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Polymeric room-temperature molten salt as a multifunctional additive toward highly efficient and stable inverted planar perovskite solar cells

Ulf Anders Hagfeldt, Ziwei He, Jiajia Suo, Chao Tang, Jiabao Yang, Bowen Yang

The inferior power conversion efficiency (PCE) compared to their regular counterparts (n-i-p) and undesirable stability issues of inverted (p-i-n) perovskite solar cells (PSCs) are the foremost issues hindering their commercialization. Here, for the first time, we demonstrate a polymeric room-temperature molten salt (poly-RTMS), namely poly(1-vinyl-3-ethyl-acetate) imidazole tetrafluoroborate (PEa), as a novel type of additive to modulate the perovskite crystallization and its electronic properties. The PEa poly-RTMS containing multiple chemical anchoring sites along with strong bonding stability can firmly bond to Pb ion defects at grain boundaries and the interface of the perovskite film via coordination bond, which effectively passivates the electronic defects and enhances the photo-, thermal-, and moisture-stability of perovskite films. As a result, the PEa-modified inverted PSCs show striking performance improvements over the control with the PCE exceeding 21.4% and excellent long-term operational stability, maintaining over 92% of the initial efficiency for 1200 hours under continuous full sun illumination at 70-75 degrees C. This strategy opens a new avenue to modulate the properties of perovskites for optoelectronic applications.

ROYAL SOC CHEMISTRY2020

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Quasi-Rayleigh model for modeling hysteresis of piezoelectric actuators

Dragan Damjanovic, Meng Zhang

Piezoelectric actuators (PEAs) have been widely used in nano-positioning applications for their high resolution of displacement. However, hysteresis, which is an inherent property of ferroelectric PEAs has been shown to significantly degrade the system performance and even system stability. In this paper, a quasi-Rayleigh model is proposed to describe the hysteresis behavior of PEAs and piezo-based systems. The microstructure of the PEAs is analyzed and the Rayleigh model is transformed into the displacement-voltage form. The Fourier series of Rayleigh model is derived and analyzed; The voltage dependence and the rate dependence of PEAs are tested and analyzed. The parameters of rate-dependent Rayleigh model are obtained and verified; To overcome the drawback of symmetric property of classical Rayleigh model, a phenomenological method is proposed. The method is based on two modified Rayleigh parameters and their corresponding coefficients, which are used to describe the ascending and descending curves of hysteresis trajectory. The experimental results demonstrate the effectiveness of the quasi-Rayleigh model.

2020

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Légume sec

vignette|upright 1.4|Différents légumes secs. Les légumes secs ou légumineuses sont des graines, issues exclusivement de plantes de la famille des Fabacées, récoltées à maturité pour la consommation h

Graine

Dans le cycle de vie des « plantes à graines », appelées spermatophytes, la graine est la structure qui contient et protège l'embryon végétal. Elle est souvent contenue dans un fruit qui permet sa

Soja

Le soja, nommé soya au Canada (Glycine max (L.) Merr.), est une espèce de plante annuelle de la famille des légumineuses (Fabaceae), originaire d'Asie orientale. Le soja cultivé Glycine max a accum

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BIO-105: Cellular biology and biochemistry for engineers

Basic course in biochemistry as well as cellular and molecular biology for non-life science students enrolling at the Master or PhD thesis level from various engineering disciplines. It reviews essential notions necessary for a training in biology-related engineering fields.

PHYS-100: Advanced physics I (mechanics)

La Physique Générale I (avancée) couvre la mécanique du point et du solide indéformable. Apprendre la mécanique, c'est apprendre à mettre sous forme mathématique un phénomène physique, en modélisant la situation et appliquant les lois de la physique.