Electric vehicles (EVs) suffer from significant driving range loss in subzero temperature environments due to reduced energy and power capability of Li-ion batteries as well as severe battery ...degradation due to Li plating. Preheating batteries to room temperature is an essential function of an effective battery management system. The present study employs an electrochemical–thermal coupled model to simulate, for the first time, the process of heating Li-ion batteries from subzero temperatures. Three heating strategies are proposed and compared using battery power, namely self-internal heating, convective heating and mutual pulse heating, as well as one strategy (AC heating) using external power. Their advantages and disadvantages are discussed in terms of capacity loss, heating time, system durability, and cost. For heating using battery power, model predictions reveal that Li-ion batteries can be heated from −20°C to 20°C at the expense of only 5% battery capacity loss using mutual pulse heating with high-efficiency dc–dc converter, implying considerable potential for improved driving range of EVs in cold weather conditions. Moreover, the heating time can be reduced to within 2min by increasing cell output power using convective heating and mutual pulse heating. For external power heating, high frequency AC signal with large amplitude is a preferred choice, offering both high heating power and improved battery cycle life.
Purpose Growing public concern about the natural environment is rapidly transforming the competitive landscape and forcing firms to adopt green innovation strategies. Many manufacturing firms have ...recognized the concept of green innovation, though there has been relatively little research on considerations of its driver and effect. The purpose of this paper is to empirically develop and test a theoretical model that analyzes how organizational green culture (OGC) influences green performance and competitive advantage. Specifically, this model explains how green innovation mediates these relationships. Design/methodology/approach The paper collected data from 327 manufacturing firms of different industry sectors in Taiwan. Structural equation modeling with AMOS 11 software was applied to analyze the data. Data on specific environmental innovation issues at the firm level are not usually available from published sources, so this paper uses a questionnaire. The questionnaire is developed based on the literature. Findings The findings of this paper suggest that OGC significantly predicted green performance and competitive advantage, respectively. Moreover, the results show that both green innovation completely mediates between OGC and green performance, and that it has a partially mediating effect on the relationship between organization green culture and competitive advantage under environmental pressure. Research limitations/implications This study has some limitations that point to the future lines of research. Perhaps, the biggest limitation of the study is that the data are from a single country, which may hamper generalization. This study is also limited in that it is based on cross-sectional data. A final limitation is the origin of organizational culture vs employee attitude culture. Originality/value This study contributes to the existing literature on organizational culture and innovation by considering green environmental concerns, which have not been empirically explored. This study also offers a unique theoretical argument describing the relationships by considering the mediating effect of green innovation strategy.
Free radicals with reactive chemical properties can fight tumors without causing drug resistance. Reactive oxygen species (ROS) has been widely used for cancer treatment, but regrettably, the common ...O2 and H2O2 deficiency in tumors sets a severe barrier for sufficient ROS production, leading to unsatisfactory anticancer outcomes. Here, we construct a chlorine radical (.Cl) nano‐generator with SiO2‐coated upconversion nanoparticles (UCNPs) on the inside and Ag0/AgCl hetero‐dots on the outside. Upon near‐infrared (NIR) light irradiation, the short‐wavelength emission UCNP catalyzes .Cl generation from Ag0/AgCl with no dependence on O2/H2O2. .Cl with strong oxidizing capacity and nucleophilicity can attack biomolecules in cancer cells more effectively than ROS. This .Cl stress treatment will no doubt broaden the family of oxidative stress‐induced antitumor strategies by using non‐oxygen free radicals, which is significant in the development of new anticancer agents.
A chlorine radical (.Cl) nano‐generator is constructed with a SiO2‐coated upconversion nanoparticle (UCNP) interior and decorated with Ag0/AgCl hetero‐dots on the outside. Upon NIR light irradiation, the emission light of the UCNPs activates Ag0/AgCl to catalyze Cl− production, generating .Cl. The resulting radicals have strong oxidizing capacity and nucleophilicity, leading to efficient tumor therapy without dependence on O2 and H2O2.
In this review, we summarize our recent progress on functionalization of the ammonium C–N bond through a transition-metal-catalysed cross-coupling process. By synergistic utilization of computational ...and experimental methods, we have successfully developed several new C–N bond cleavage protocols and established new reaction mechanisms. These findings provide new possibilities for transforming naturally abundant chemicals into useful functional molecules in an efficient and selective manner.
Increasing energy density of Li-ion batteries (LiBs) along with fast charging capability are two key approaches to eliminate range anxiety and boost mainstream adoption of electric vehicles (EVs). ...Either the increase of energy density or of charge rate, however, heightens the risk of lithium plating and thus deteriorates cell life. The trilemma of fast charging, energy density and cycle life are studied systematically in this work utilizing a physics-based aging model with incorporation of both lithium plating and solid-electrolyte-interphase (SEI) growth. The model is able to capture the key feature of temperature-dependent aging behavior of LiBs, or more specifically, the existence of an optimal temperature with the longest cycle life. We demonstrate that this optimal temperature is a result of competition between SEI growth and lithium plating. Further, it is revealed that either the increase of charge rate or of energy density accelerates lithium plating induced aging. As such, the optimal temperature for cell life increases from ∼20 °C for a high-power cell at 1C charge to ∼35–45 °C with the increase of charge rate and/or energy density. It would be beneficial to further increase the charge temperature in order to enable robust fast charging of high energy EV cells.
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•Temperature-dependent aging behavior of Li-ion battery is studied numerically.•Overall aging rate depends on the competition of lithium plating and SEI growth.•The optimal temperature for cycle life increases with charge rate & energy density.•Raising charging temperature is an effective method to eliminating lithium plating.
Calcium (Ca
2+
) is a unique mineral that serves as both a nutrient and a signal in all eukaryotes. To maintain Ca
2+
homeostasis for both nutrition and signaling purposes, the tool kit for Ca
2+
...transport has expanded across kingdoms of eukaryotes to encode specific Ca
2+
signals referred to as Ca
2+
signatures. In parallel, a large array of Ca
2+
-binding proteins has evolved as specific sensors to decode Ca
2+
signatures. By comparing these coding and decoding mechanisms in fungi, animals, and plants, both unified and divergent themes have emerged, and the underlying complexity will challenge researchers for years to come. Considering the scale and breadth of the subject, instead of a literature survey, in this review we focus on a conceptual framework that aims to introduce readers to the principles and mechanisms of Ca
2+
signaling. We finish with several examples of Ca
2+
-signaling pathways, including polarized cell growth, immunity and symbiosis, and systemic signaling, to piece together specific coding and decoding mechanisms in plants versus animals.
Lipid droplets, lipophagy, and beyond Wang, Chao-Wen
Biochimica et biophysica acta,
August 2016, 2016-Aug, 2016-08-00, Volume:
1861, Issue:
8
Journal Article
Peer reviewed
Lipids are essential components for life. Their various structural and physical properties influence diverse cellular processes and, thereby, human health. Lipids are not genetically encoded but are ...synthesized and modified by complex metabolic pathways, supplying energy, membranes, signaling molecules, and hormones to affect growth, physiology, and response to environmental insults. Lipid homeostasis is crucial, such that excess fatty acids (FAs) can be harmful to cells. To prevent such lipotoxicity, cells convert excess FAs into neutral lipids for storage in organelles called lipid droplets (LDs). These organelles do not simply manage lipid storage and metabolism but also are involved in protein quality management, pathogenesis, immune responses, and, potentially, neurodegeneration. In recent years, a major trend in LD biology has centered around the physiology of lipid mobilization via lipophagy of fat stored within LDs. This review summarizes key findings in LD biology and lipophagy, offering novel insights into this rapidly growing field. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.
•Lipid droplets are metabolically active organelles that store neutral lipids.•Lipid droplets are linked to diverse cellular processes beyond lipid metabolism.•Lipophagy sequesters lipid droplets to lytic compartments for lipid catabolism.•A complex lipophagy and lipolysis crosstalk underlies cellular lipid homeostasis.
Amorphous iron phosphate (FePO4) has attracted enormous attention as a promising cathode material for sodium‐ion batteries (SIBs) because of its high theoretical specific capacity and superior ...electrochemical reversibility. Nevertheless, the low rate performance and rapid capacity decline seriously hamper its implementation in SIBs. Herein, we demonstrate a sagacious multi‐step templating approach to skillfully craft amorphous FePO4 yolk–shell nanospheres with mesoporous nanoyolks supported inside the robust porous outer nanoshells. Their unique architecture and large surface area enable these amorphous FePO4 yolk–shell nanospheres to manifest remarkable sodium storage properties with high reversible capacity, outstanding rate performance, and ultralong cycle life.
FePO4 nanospheres consisting of mesoporous nanoyolks supported inside robust porous nanoshells are synthesized by a judicious multi‐step templating strategy using carbon nanospheres as the starting material. Their architecture and composition allow these hierarchical FePO4 yolk–shell nanospheres to manifest excellent sodium storage performance as a cathode material for sodium‐ion batteries.
P2‐type layered oxides suffer from an ordered Na+/vacancy arrangement and P2→O2/OP4 phase transitions, leading them to exhibit multiple voltage plateaus upon Na+ extraction/insertion. The deficient ...sodium in the P2‐type cathode easily induces the bad structural stability at deep desodiation states and limited reversible capacity during Na+ de/insertion. These drawbacks cause poor rate capability and fast capacity decay in most P2‐type layered oxides. To address these challenges, a novel high sodium content (0.85) and plateau‐free P2‐type cathode‐Na0.85Li0.12Ni0.22Mn0.66O2 (P2‐NLNMO) was developed. The complete solid‐solution reaction over a wide voltage range ensures both fast Na+ mobility (10−11 to 10−10 cm2 s−1) and small volume variation (1.7 %). The high sodium content P2‐NLNMO exhibits a higher reversible capacity of 123.4 mA h g−1, superior rate capability of 79.3 mA h g−1 at 20 C, and 85.4 % capacity retention after 500 cycles at 5 C. The sufficient Na and complete solid‐solution reaction are critical to realizing high‐performance P2‐type cathodes for sodium‐ion batteries.
A high sodium content (0.85) and plateau‐free P2‐type cathode, Na0.85Li0.12Ni0.22Mn0.66O2, is developed for sodium‐ion batteries. The sodium content promises a large specific capacity of 123.4 mA h g−1 with an average working voltage as high as 3.5 V. The complete solid‐solution reaction over a wide voltage range ensures small volume variation (1.7 %) and fast Na+ kinetics (10−10 to 10−11 cm2 s−1), contributing to both excellent cycling stability and rate capability.
In this paper, we propose a deep reinforcement learning (DRL)-based method that allows unmanned aerial vehicles (UAVs) to execute navigation tasks in large-scale complex environments. This technique ...is important for many applications such as goods delivery and remote surveillance. The problem is formulated as a partially observable Markov decision process (POMDP) and solved by a novel online DRL algorithm designed based on two strictly proved policy gradient theorems within the actor-critic framework. In contrast to conventional simultaneous localization and mapping-based or sensing and avoidance-based approaches, our method directly maps UAVs' raw sensory measurements into control signals for navigation. Experiment results demonstrate that our method can enable UAVs to autonomously perform navigation in a virtual large-scale complex environment and can be generalized to more complex, larger-scale, and three-dimensional environments. Besides, the proposed online DRL algorithm addressing POMDPs outperforms the state-of-the-art.
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