Low Energy Research Articles

Instrumented bio-inspired cable-driven compliant continuum robot: static modeling and experimental evaluation

Abstract Energy efficiency is inherent for autonomous robotic device. Snakes are well known for their ability to low energy consumption when swimming. However, the swimming know-how is poorly understood. Designing a snake robot inspired by snakes as a tool to find out the swimming energy efficiency crucial point will lead to the development of hyper efficient undulating locomotors. In this article, we introduce a four tendons driven continuum robot made of bio-inspired compliant vertebrae to assess the energy consumption of a planar and a spatial snake motion. The tendon-driven continuum robot constitutes the head–neck part of a locomotor snake robot. A static modeling coupled with an optimization method was implemented to generate bio-inspired motions recorded on snake swimming head. A friction model describing the friction between cables and the disks is investigated and compared to a frictionless model. The proposed prototype is equipped with exteroceptive sensors to record motion and proprioceptive sensors to measure cable forces applied at the tip of the robot. Hence, the work of the forces, thus the energy required to execute a trajectory are computed and analyzed. The energy is introduced as a key criterion to assess the swimming motion of a locomotor snake robot.

Expanding Automated Multiconformer Ligand Modeling to Macrocycles and Fragments.

Small molecule ligands exhibit a diverse range of conformations in solution. Upon binding to a target protein, this conformational diversity is generally reduced. However, ligands can retain some degree of conformational flexibility even when bound to a receptor. In the Protein Data Bank (PDB), a small number of ligands have been modeled with distinct alternative conformations that are supported by X-ray crystallography density maps. However, the vast majority of structural models are fit to a single ligand conformation, potentially ignoring the underlying conformational heterogeneity present in the sample. We previously developed qFit-ligand to sample diverse ligand conformations and to select a parsimonious ensemble consistent with the density. While this approach indicated that many ligands populate alternative conformations, limitations in our sampling procedures often resulted in non-physical conformations and could not model complex ligands like macrocycles. Here, we introduce several improvements to qFit-ligand, including the use of routines within RDKit for stochastic conformational sampling. This new sampling method greatly enriches low energy conformations of small molecules and macrocycles. We further extended qFit-ligand to identify alternative conformations in PanDDA-modified density maps from high throughput X-ray fragment screening experiments. The new version of qFit-ligand improves fit to electron density and reduces torsional strain relative to deposited single conformer models and our previous version of qFit-ligand. These advances enhance the analysis of residual conformational heterogeneity present in ligand-bound structures, which can provide important insights for the rational design of therapeutic agents.

Fission of 180\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{180}$$\\end{document}Hg and 264\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{264}$$\\end{document}Fm: a comparative study

180\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{180}$$\\end{document}Hg is experimentally found to fission asymmetrically. This result was not expected as a naive fragment shell effects study would support the symmetric mode to be the most probable. In the present study we investigate both symmetric and asymmetric 180\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{180}$$\\end{document}Hg fission modes at the mean field level using various multipole moment constraints. Potential energy surfaces are analysed in terms of shell effects that shape their topographies and connections to fragment shell effects are made. The non-occurrence of low energy symmetric fission is interpreted in terms of 90\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{90}$$\\end{document}Zr fragment properties. Throughout this study a comparison with 264\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{264}$$\\end{document}Fm and its symmetric doubly magic 132\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{132}$$\\end{document}Sn fission fragments is done.

Technology Progress in High-Frequency Electromagnetic In Situ Thermal Recovery of Heavy Oil and Its Prospects in Low-Carbon Situations

Heavy oil resources are abundant globally, holding immense development potential. However, conventional thermal recovery methods such as steam injection are plagued by high heat loss, substantial carbon emissions, and significant water consumption, making them incompatible with carbon reduction goals and the sustainable socioeconomic development demands. A new method of high-frequency electromagnetic in situ heating, which targets polar molecules, can convert electromagnetic energy into heat so as to achieve rapid volumetric heating of the reservoir. This method has the potential to overcome the drawbacks of traditional techniques. Nevertheless, it faces significant drawbacks such as limited heating range and inadequate energy supply during later production stages, which necessitates auxiliary enhancement measures. Various enhancement measures have been reported, including nitrogen injection, hydrocarbon solvent injection, or the use of nano-metal oxide injections. These methods are hindered by issues such as pure nitrogen being easy to breakthrough, high costs, and metal pollution. Through extensive literature review, this article charts the evolution of high-frequency electromagnetic in situ heating technology for heavy oil and the current understanding of the coupled heat and mass transfer mechanisms underlying this technology. Moreover, based on a profound analysis of the technology’s progression trends, this work introduces a new direction: CO2-N2 co-injection as an enhancement strategy for high-frequency electromagnetic in situ heavy oil recovery. There is promising potential for the development of new technologies in the future that combine high efficiency, low carbon emissions, environmental friendliness, economic viability, and energy conservation. Furthermore, some research prospects in low-carbon situations and challenges for the new technology in future are presented in detail. All in all, the contribution of the paper lies in the summarizing of some main drawbacks of current enhanced electromagnetic in situ thermal recovery methods, and presents a novel research direction of using CO2-N2 co-injection as an enhancement strategy based on its current research status in low-carbon situations.

Na3.5(MnVFeTi)0.5(PO4)3: A Multi‐transition‐metal‐ion‐engineered NASICON‐type Cathodes for Sodium Ion Batteries

Electrochemically active Na‐superconductor (NASICON)‐type cathodes have the structural flexibility to include various transition elements, thus enabling high power outputs benefited by multi‐electron redox reactions. This study amalgamated multiple transition metal ions to construct a new NASICON‐type cathode i.e., carbon coated Na3.5(MnVFeTi)0.5(PO4)3 (NMVFTP/C), for Na‐ion batteries (NIBs). The NMVFTP/C cathode engineered in this study demonstrated stable Na+‐storage capacity, including long‐term cycling stability up to 4000 cycles at 3000 mA g‐1 with 96% capacity retention and a high‐rate output capacity of 86.78 mAh g‐1 at 2500 mA g‐1. To elucidate the ion transport process within the cathode, density functional theory modeling was employed. The low energy barrier for the diffusion of Na+ in the NMVFTP/C materials was proved to be a key factor supporting our material’s superior electrochemical performances.

Kajian Farmakoinformatika Senyawa Caulerchlorin dan Racemosin sebagai kandidat Antimalaria

Caulerchlorin and racemosin were bioactive compounds containing in Caulerpa racemosa macroalgae. Previous study, those compounds promoted therapeutical target on metabolic syndrome. However, the therapeutical activity on Malaria not yet defined. Therefore, this study investigated potential activity of caulerchlorin and racemosin from Caulerpa racemosa as antimalarial activity through pharmacoinformatic study. Caulerchlorin and racemosin structures were retrieved from PubChem NCBI and the Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) structure was taken out from Protein database with ID 5GJG. Orotic acid was used as native ligand or control. Ligands were predicted their antiplasmodial activity and toxicity. Ligands and protein were interacted by redocking using Molegro Virtual Docker version 6.0 and analyzed by using PyMol 2.3 and Discovery Studio version 21.1.1. Two bioactive compounds also showed antiplasmodial activity and were not mutagenicity and hepatotoxicity affections. Molecular docking performed that caulerchlorin and racemosin exhibited same active residues as well as orotic acid as native substrate. Binding energy revealed two compounds, caulerchlorin and racemosin showed lower binding energy than orotic acid. In summary caulerchlorin and racemosin were potentially inhibited PfDHODH activity by binding substrate sites of PfDHODH protein.

Thermo-economic analysis of sun drying patio coffee in the Sierra Mariscal, Chiapas-México

This study shows a thermo-economic analysis of patio coffee drying in the Sierra Mariscal Chiapas-México to optimize bed thickness. The drying time, specific energy, thermal efficiency, water-effective diffusivity, and drying batch costs were correlated with bed thickness and solar irradiation. The initial and final coffee moisture contents were 53 % and 11–12 % (w.b). The bed thickness was in terms of kilograms of coffee uniformly spread on a square meter (2.0, 5.0, 10.0, 15.0, and 20.0 kg/m2). The five experimental campaigns involved five tests over a harvest season. The water-effective diffusion coefficient increases with bed thickness (0.38–91.2 × 10−10 m2/s). The solar irradiation requirement and the efficiency of the patio drying linearly increase with bed thickness while specific energy exponentially decreases. The lower specific energy was (7.1–10.4 MJ/kg) for the higher bed thickness (20.0 kg/m2), with (24.0–38.0 h) of drying time and (0.22–0.32) of efficiency. The optimized coffee bed thickness was 10 kg/m2, with a specific energy of 8.8–9.6 MJ/kg. When bed thickness increases, the thermal efficiency increases almost linearly 5.5 times, exponentially reducing the drying cost per batch five times. However, increasing drying times shall lessen the quality of physical-chemical and sensorial coffee.

An electronic energy compensation method for flattening the energy response of SiPM-GGAG:Ce,B based gamma detector

Abstract The energy response of gross gamma dose rate monitors needs to be flat in order to prevent overestimation of dose at low gamma energies. In this paper, a discriminator threshold modulation based electronic energy compensation algorithm has been proposed for SiPM-scintillator based gamma detectors. Theoretical simulation studies were carried out in order to optimize the parameters of the periodic ramp voltage used for modulation of the discriminator threshold of a SiPM-GGAG:Ce,B based gamma dose rate monitor. A customized threshold modulation circuit and signal processing electronics were developed for this gamma detector. For experimentally optimizing the parameters, the energy response studies of the detector, with and without the discriminator threshold modulation, were carried out. With the optimized parameters for a periodic ramp threshold, the count rates for 241Am (60 keV) and 60Co (1173 and 1332 keV) were observed to be within ±30% of the count rate obtained for 137Cs (662 keV). Using the electronic energy compensation techniques presented in this paper, a flat energy response of the SiPM-scintillator gamma detector for the energy range of 60 keV to 1.5 MeV could be achieved.

Winning the transition: Strategic state action in France and Germany amid the low carbon transition and energy shock

European economies are in flux, destabilized by the low carbon transition (LCT) and post-Ukraine energy shock. How are states responding to this instability? This article contributes to emerging environmentally focused Comparative Capitalisms (CC) scholarship by developing a novel framework for analysing how state action is shaped by the demand-competitiveness-energy nexus. We comparatively examine the cases of France and Germany since 2022, drawing upon 19 elite interviews and documentary analysis of stakeholder accounts, to advance three arguments. First, it is essential for CC frameworks to integrate energy supply dynamics to understand state action and processes of capitalist development. Second, the asymmetric impact of the LCT on France and Germany has shaped distinct state-led capitalist restructuring designed to protect and extend national competitive advantages. For Germany, this has primarily involved ‘greening’ its existing export-led model of growth, whereas French state actors are attempting to advance its interests via the ‘strategic autonomy’ (SA) agenda at the domestic and regional levels. Finally, the energy shock has initiated more interventionist state action in Germany that exposes critical instabilities in its export-led growth model. This analysis has significant implications for CC scholarship and its understanding of capitalist development by illustrating the significance of energy supply dynamics and advancing understanding of how disequilibrium can be theorized within the literature.

Zeolites as Solid Solvents: Explaining the Chloromethane Hydrolysis over Metal-Exchanged Zeolite Y by DFT Calculations.

We report a theoretical DFT study of the reaction pathways for chloromethane hydrolysis over metal-exchanged zeolites (Li+, Na+, K+, and Mg2+). A cluster of 78 T atoms (T referring to Si or Al atoms), comprising the zeolite Y super cavity coupled with the sodalite cage and three hexagonal prism units (Si(78-x)Al x O129H54; x = 1 or 2), was used in the calculations. The study was carried out using the ONIOM method. The high layer was computed at M062X/6-31++G(d,p), whereas the low layer was computed at the PM6 level of theory. The energy profile was obtained by single-point calculations at the M062X/6-31++G(d,p) for the entire structure. The first step studied was the adsorption of chloromethane on the zeolite, which involves an ion-dipole interaction between the metal cation and the chlorine atom. Then, two mechanistic pathways were investigated: one via formation of an adsorbed methoxide and the other involving a direct, one-step, nucleophilic attack of the water molecule to the adsorbed chloromethane. In all systems studied, the direct mechanism showed a lower energy of activation than the route involving the methoxide intermediate. The same behavior was also observed for chloromethane methanolysis to afford dimethyl ether on the metal-exchanged zeolites. The theoretical results are in agreement with the experiments of chloromethane hydrolysis over metal-exchanged zeolite Y, explaining the formation of dimethyl ether upon chloromethane methanolysis on zeolites of low or no acidity. The transition state for the direct route resembles a SN2 process assisted by the surface, reinforcing the concept of zeolites as solid solvents, providing a polar nanoenvironment that favors and assists the formation of ionic transition states and intermediates.

Artificially regulated interphase on natural graphite realizes rapid charge and durable high-temperature cycling of Li-ion batteries

Natural graphite (NG) is a strong competitor in the anode market of Li-ion batteries because of its low cost, rich resource, low energy consumption and low carbon dioxide emission during production. The main problems inhibiting its universal application are its high surface area and the attendant unstable solid/electrolyte interphase (SEI), leading to unsatisfactory cycling and rate performance. In this work, a Li+-conductive, thermally and mechanically stable organic polymer layer is successfully constructed on NG surface by virtue of the simultaneous polymerization and crosslinking reactions of chitosan (CS) and acrylic acid (AA). With controllable thickness, the polymer layer denoted as CSAA significantly decreases the specific surface area of NG, works as an inner SEI substrate greatly mitigating the decomposition of electrolyte, and induces the formation of a LiF-rich SEI outer layer. The SEI resistance and activation energy for charge-transfer reactions are considerably reduced. Benefiting from the superior properties of CSAA-derived SEI, the NG@CSAA anodes exhibit a high initial coulombic efficiency of 94.1 %, fast charge/discharge capability and prolonged cycle life at both 25 °C and 45 °C in the LiFePO4 cathodes-based full cells.

Preparation and properties of fluorinated VAc-VeoVa10 latex emulsified with allyl nonyl phenoxy propyl alcohol polyoxyethylene ether ammonium sulphate

Purpose The traditional VeoVa10-VAc copolymer latex, which prepared via the emulsion polymerization of the mixed monomers of VAc and VeoVa10, has the poor water resistance and thermal stability because of the migration of the conventional emulsifier molecules and the low bond energy of C-C bond. The purpose of this work is that the fluorinated monomer is used to modify the latex. The film of the resultant latex has the C-F bond with high bond energy and low surface energy, which can effectively improve the heat resistance and water resistance of the resultant film. In addition, the reactive emulsifier is used to replace the conventional emulsifier. The drawbacks of the conventional emulsifier molecules migrate and desorb can be avoided when the polymer latex is stored, thereby also improving the water resistance. Design/methodology/approach The modified VAc-VeoVa10 latex has been successfully synthesized via the semi-continuous seeded emulsion polymerization, which VAc and VeoVa10 is used as the main monomers and HFMA was used as the functional monomer. KPS and reactive surfactants of SE-10 were used as the initiator and emulsifier, respectively. The structure of resultant latex film was characterized by Fourier transform infrared spectroscopy (FTIR). The latex films were tested by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and contact angle (CA). The particle size and its distribution of the latex were measured by the nano particle size analyzer. Findings The factors that had an influence on the properties of the latex and the film were investigated in detail. The stability of the resultant latex is good. The average particles of the latex and its distribution are small and uniform, respectively. In comparison with the conventional latex film, the thermal stability and hydrophobicity of the resultant latex film are improved obviously. Practical implications The resultant latex can be used in both the waterborne interior and exterior wall coatings, pickering stabilized waterborne polymer dispersions, polymer powders, environmentally friendly polymer-modified waterproof mortar and other fields, which can be satisfied with the high demand of thermal stability and hydrophobicity. Originality/value The modification of poly (VAc-VeoVa10) by reactive surfactant and fluorinated monomer is seldom reported. In this study, the fluorinated poly (VAC-VeoVa) latex is prepared via the reactive surfactants, which VAc and VeoVa10 is used as the main monomers and hexafluorobutyl methacrylate is used as the functional monomer. Potassium persulfate (KPS) and allyl nonyl phenoxy propyl alcohol polyoxyethylene ether ammonium sulfate are used as the initiator and emulsifier, respectively.

Design, Synthesis, Antimicrobial Activity and Molecular Docking of Novel Pyridine, Thiophene, and Thiadiazole Scaffolds Utilizing 2-Cyano-N-(4-(1-(2-(2-cyanoacetyl)hydrazineylidene)ethyl)phenyl)acetamide

An efficient protocol is reported for synthesizing arylidene adducts, pyridine derivatives, in excellent yields by treating 2-cyano-N-(4-(1-(2-(2-cyanoacetyl) hydrazineylidene) ethyl)phenyl)acetamide with quinoline-3-carbaldehydes, 2-arylidenemalononitriles, and acetylacetone in EtOH, respectively. In addition, dithiadiazole and dithiophene adducts were synthesized from one pot reaction using phenyl isothiocyanate, and either hydrazonyl chloride or 2-bromo-1-(5-methyl-1-(p-tolyl)-1H-1,2,3-triazole-4-yl)ethan-1-one in DMF containing potassium hydroxide. The structure of novel products was elucidated using spectroscopic data and elemental analyses. The synthesized compounds were evaluated for their antimicrobial activities. The compounds showed antibacterial and antifungal activities against the tested G-ve and G+ve bacteria and against the tested fungi. The MIC was mostly in the range of 100-500 μg/mL. Molecular docking was used to analyse interactions between the compounds and antimicrobial target proteins. The molecular docking simulation showed lower binding energy with different types of interaction at the active site of Sterol 14-demethylase of C. albicans, Fdc1 proteins of A. niger, DNA Gyrase of E. coli, and LasR, an activator of exotoxin. An expression of P. aeruginosa indicates that these compounds could inhibit the enzyme and cause promising antimicrobial effects.

Achieving Near-Infrared Highly Sensitive Temperature Sensing in Lanthanide-Doped Lead-Free Double Perovskite NaLaMgWO6 with Significant Thermal Enhancement.

The significant temperature response of lanthanide-doped up-conversion luminescent materials is typically characterized by a severe thermal quenching of the luminescence intensity at elevated ambient temperatures, which severely restricts materials' capability in temperature sensing. Herein, the influence of matrix phonon properties on the remarkable thermal enhancement effect in the thermosensitive material NaLaMgWO6:Yb3+/Nd3+ is reported. It is elucidated that achieving a significant thermal enhancement of Nd3+ with a higher phonon energy oxide matrix is easier than a halide matrix, which has lower phonon energy by comparison with previous findings. Interestingly, the emission of thermally related levels gets enhanced to various extents through phonon-assisted thermal population. In light of this, a three-model thermometer is constructed based on luminescence intensity ratio (LIR) technology. Given that Sr and ΔE possess a positive correlation, it is feasible to acquire greater temperature monitoring sensitivity Sr in Nd3+, which has a larger ΔE. At 313 K, this thermometry model may achieve a maximum sensitivity of 2.84%·K-1. This work not only provides guidance for the selection of efficient near-infrared up-conversion material but also opens up a prospect for the realization of ultrasensitive thermally coupled luminescent thermometers.

Baseline factors relating to depressive symptoms at one year postoperative in patients with diffuse glioma

Abstract Background Depressive symptoms are common in patients with diffuse glioma, potentially reducing their quality of life. Understanding baseline factors associated with the development of depressive symptoms is important for psychoeducation and early intervention. This study investigates the associations of baseline patient- and tumor-related characteristics and depressive symptoms one year after surgery. Methods We combined retrospective longitudinal datasets from Amsterdam UMC and Rigshospitalet Copenhagen. Several characteristics of patients and tumors were retrieved, in particular items of their mood and functioning status. Depression instruments were harmonized to the PROMIS Depression scale through previously-developed item response theory. Functioning items were harmonized to the International Classification of Functioning, Disability and Health (ICF) domains using linking methods published previously. We analyzed the associations of 25 baseline factors with depressive symptoms one year after surgery by multivariable stepwise backward linear regression models and verified model robustness using best subset selection. Results We included 118 patients with diffuse glioma with a mean age of 48 years and a glioblastoma in 29%. Baseline depressive symptoms, lower ICF energy, and impaired ICF language functioning were associated with more depressive symptoms at follow-up in the multivariable model (R-squared: 0.379). Conclusions We identified three key baseline factors associated with depressive symptoms one year after surgery. Clinically, our findings contribute to the comprehension of predictive factors for depressive symptoms, aiding healthcare providers and patients in understanding and possibly allowing for early intervention.

Dynamic gain driven mode-locking in GHz fiber laser

Ultrafast lasers have become powerful tools in various fields, and increasing their fundamental repetition rates to the gigahertz (GHz) level holds great potential for frontier scientific and industrial applications. Among various schemes, passive mode-locking in ultrashort-cavity fiber laser is promising for generating GHz ultrashort pulses (typically solitons), for its simplicity and robustness. However, its pulse energy is far lower than the critical value of the existing theory, leading to open questions on the mode-locking mechanism of GHz fiber lasers. Here, we study the passive mode-locking in GHz fiber lasers by exploring dynamic gain depletion and recovery (GDR) effect, and establish a theoretical model for comprehensively understanding its low-threshold mode-locking mechanism with multi-GHz fundamental repetition rates. Specifically, the GDR effect yields an effective interaction force and thereby binds multi-GHz solitons to form a counterpart of soliton crystals. It is found that the resulting collective behavior of the solitons effectively reduces the saturation energy of the gain fiber and permits orders of magnitude lower pulse energy for continuous-wave mode-locking (CWML). A new concept of quasi-single soliton defined in a strongly correlated length is also proposed to gain insight into the dynamics of soliton assembling, which enables the crossover from the present mode-locking theory to the existing one. Specifically, two distinguishing dynamics of Q-switched mode-locking that respectively exhibit rectangular- and Gaussian-shape envelopes are theoretically indicated and experimentally verified in the mode-locked GHz fiber laser through the measurements using both the standard real-time oscilloscope and emerging time-lens magnification. Based on the proposed criterion of CWML, we finally implement a GDR-mediated mode-locked fiber laser with an unprecedentedly high fundamental repetition rate of up to 21 GHz and a signal-to-noise ratio of 85.9 dB.

Non-Radiative Deactivation in Isolated Quinoline.

The photophysics of the S2 1(ππ*) state of the polycyclic aromatic nitrogen-containing hydrocarbon (PANH) quinoline is investigated in a free jet using a picosecond laser system. A [1 + 1] multiphoton ionization spectrum yields the S2 origin at around 32 200 cm-1 and reveals several vibronic bands. In time-resolved experiments, quinoline is then excited between 312.2 and 279.7 nm. Probe wavelengths of 351 and 263.5 nm are employed. The dynamics is monitored by time-resolved photoelectron imaging. The images reveal a short-lived band at high electron kinetic energies with a ps lifetime and a band at lower electron kinetic energies that shows an offset at long delay times. In comparison with previous work, the offset is assigned to ionization from the T1 state. Lifetimes decrease from 45 ps at the S2 origin to 11 ps at +3550 cm-1. Most likely, the S2 1(ππ*) state deactivates by internal conversion to the S1 1(nπ*) state, followed by intersystem crossing to the triplet manifold.

Performance Analysis of Low Frequency Piezoelectric Energy Harvesting Systems with Multiple Nonlinear Factors and Bidirectional Excitations

Performance Analysis of Low Frequency Piezoelectric Energy Harvesting Systems with Multiple Nonlinear Factors and Bidirectional Excitations

Spatiotemporal patterns in the active cyclic Potts model

Abstract The nonequilibrium dynamics of a cycling three state Potts model is studied on a square lattice using Monte Carlo simulations and continuum theory. This model is relevant to chemical reactions on a catalytic surface and to molecular transport across a membrane. Several characteristic modes are formed depending on the flipping energies between successive states and the contact energies between neighboring sites. Under cyclic symmetry conditions, cycling homogeneous phases and spiral waves form at low and high flipping energies, respectively. In the intermediate flipping energy regime, these two modes coexist temporally in small systems and/or at low contact energies. Under asymmetric conditions, we observed small biphasic domains exhibiting amoeba-like locomotion and temporal coexistence of spiral waves and a dominant non-cyclic one-state phase. An increase in the flipping energy between two successive states, say state 0 and state 1, while keeping the other flipping energies constant, induces the formation of the third phase (state 2), owing to the suppression of the nucleation of state 0 domains. Under asymmetric conditions regarding the contact energies, two different modes can appear depending on the initial state, due to a hysteresis phenomenon.

Electrospinning Fiber Membrane‐Derived Gel Polymer Electrolytes with High Mechanical Strength and Low Swelling Effect for High‐Safety Lithium Metal Batteries

AbstractThe practical application of lithium metal batteries (LMBs) is hindered by the issues of flammable electrolytes, lithium dendrites and the resulting thermal runaway. Designing flame‐retardant electrolytes with high performance is a valid strategy to break the current dilemma. In this work, the flame retardant of triphenyl phosphate (TPP) is elaborately encapsulated into the polymer shell of polyacrylonitrile (PAN) and polyvinylidene fluoride‐hexafluoropropylene (PVDF‐HFP) to realize the controllable release of TPP during the soaking process. The resulting TPP@PAN/PVDF‐HFP fiber membrane holds high thermal stability, high mechanical strength, and low swelling rate, which is essential for the preparation of flame‐retardant gel polymer electrolyte (GPE). As demonstrated, the TPP@PAN/PVDF‐HFP GPE can deliver high Li+ transference number of 0.877, low interfacial activation energy barrier of 26.6 kJ mol−1 and heterogeneous SEI composition of Li3PO4/Li2CO3/LiF. The corresponding Li||Li cells achieve stable voltage polarization over 1000 h, and the Li||Cu cells display high plating/stripping CE of 99.1%. Meanwhile, the optimized Li||LiFePO4 batteries exhibit high reversible capacity of 158 mAh g−1 after 200 cycles at 0.5 C, and present outstanding fire resistance through the thermal runaway and puncture test. This study will open window for the design of high‐safety electrolytes to promote the practical application of LMBs.