Promoting light absorption range of photocatalysts is of great significance to improve solar light‐driven photocatalytic CO2 reduction efficiency. Herein, a new viologen‐based multicomponent ...heterotrimetallic metal–organic framework (MOF) Cu3Th6(µ3‐O)4(µ3‐OH)4(cpb)12FeIII(CN)66 (IHEP‐14) with an unprecedented (6, 18)‐connected she‐d topology is presented. Upon UV irradiation, this MOF undergoes ligand and iron photoreduction, and a single‐crystal‐to‐single‐crystal transformation to generate persistent radical‐containing MOF Cu3Th6(µ3‐O)4(µ3‐OH)4(cpb•)12FeII(CN)66 (IHEP‐15). This radical‐containing MOF shows excellent stability without fading after at least 2 months in air. Besides extending the photoabsorption to a wider wavelength range covering from 200 to 2,500 nm, the generation of persistent radical in IHEP‐15 also largely enhances its CO2 adsorption capacity by a factor of three due to the strong affinity between π orbital of the radical and the π system of CO2. These attributes endow IHEP‐15 with excellent visible/NIR light‐driven CO2 photoreduction activity, with CO production rates under visible and NIR irradiation of 570.3 and 209.3 µmol h−1 g−1, respectively. Notably, the latter is a record high for NIR‐induced CO production among all MOFs reported so far.
A single‐crystal‐to‐single‐crystal (SCSC) transformation of unprecedented (6, 18)‐connected multicomponent MOF IHEP‐14 generates persistent radical‐containing MOF IHEP‐15, accompanied by a marked increase in CO2 sorption and visible/NIR photocatalytic reduction of CO2 to CO with high selectivity. The NIR light‐driven CO production rate of 209.3 µmol h−1 g−1 for IHEP‐15 is recorded high for NIR‐induced CO production among all MOFs reported so far.
There are two common challenges in particle swarm optimization (PSO) research, that is, selecting proper exemplars and designing an efficient learning model for a particle. In this article, we ...propose a triple archives PSO (TAPSO), in which particles in three archives are used to deal with the above two challenges. First, particles who have better fitness (i.e., elites) are recorded in one archive while other particles who offer faster progress, called profiteers in this article, are saved in another archive. Second, when breeding each dimension of a potential exemplar for a particle, we choose a pair of elite and profiteer from corresponding archives as two parents to generate the dimension value by ordinary genetic operators. Third, each particle carries out a specific learning model according to the fitness of its potential exemplars. Furthermore, there is no acceleration coefficient in TAPSO aiming to simplify the learning models. Finally, if an exemplar has excellent performance, it will be regarded as an outstanding exemplar and saved in the third archive, which can be reused by inferior particles aiming to enhance the exploitation and to save computing resources. The experimental results and comparisons between TAPSO and other eight PSOs on 30 benchmark functions and four real applications suggest that TAPSO attains very promising performance in different types of functions, contributing to both higher solution accuracy and faster convergence speed. Furthermore, the effectiveness and efficiency of these new proposed strategies are discussed based on extensive experiments.
•Blending butanol or pentanol with biodiesel changed the DPM characteristics.•The blends reduced EC and DPM emissions, but increased WSOC and OC fractions.•They reduced emissions of total ...particle-phase PAHs and also carcinogenic potential.•They showed different effects on counts of nanoparticles and lager particles.
A systematic study was conducted to make a comparative evaluation of the effects of blending n-butanol and n-pentanol with biodiesel at 10% and 20% by volume on engine performance and on the physico-chemical characteristics of particulate emissions from a single cylinder, direct injection diesel engine. The engine was operated at a constant engine speed and at three engine loads. Compared to biodiesel, butanol–biodiesel blends lead to a maximum of 1.6% increase in the brake thermal efficiency (BTE) and an increase in the brake specific fuel consumption (BSFC) by 1.9–3.9% at low and medium engine loads. Pentanol–biodiesel blends result in an improvement in the BTE and a maximum of 2% increase in the BSFC. Compared to biodiesel, both the blended fuels can reduce the particulate mass and elemental carbon (EC) emissions, with butanol being more effective than pentanol. The blended fuels also show a lower emission of total particle-phase polycyclic aromatic hydrocarbons (PAHs) and also a lower carcinogenic potential. However, the proportion of particulate-bound organic carbon (OC) and water-soluble organic carbon (WSOC) are increased for the both blended fuels, especially for 20% butanol in blends. The emissions of volatile and solid particles are reduced significantly in terms of their counts for both kinds of blended fuels at medium and high engine loads, whereas the total particle counts for both 10% and 20% butanol in blended fuels are increased at low engine load due to a significant increase in particles with diameter less than 15nm.
Self-healing coating based on nanocontainers (NCs) has been emerging as a great strategy to improve the anticorrosion ability of susceptible metal substrate. However, all the research referred to ...such smart coating to date is focus on organic coating instead of metallic coating. To fill this gap, 2-mercaptobenzothiazole (MBT) loaded porous hollow SiO
2
NCs are synthesized and incorporated successfully into an electroless Ni coating on Mg alloy in this work. The surface morphologies and the loading properties of the NCs are characterized by scanning electron microscopy, transmission electron microscopy, ultraviolet–visible spectrophotometer, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The favorable performance of Ni coating after incorporation of NCs is demonstrated by potentiodynamic polarization (PDP), linear polarization, and electrochemical impedance spectroscopy. Based on the results of PDP test, the corrosion current density (
i
c
) of the MBT@NCs (MNCs)-engineered Ni coating reduces slightly from 6.4 to 5.4 μA cm
−2
after immersion in a corrosive media, while the value for MNCs-free coating increases by almost a factor of ten from 6.8 to 67.4 μA cm
−2
. Our findings demonstrate the possibility of using corrosion inhibitors loaded NCs to enhance the corrosion resistance of a metallic coating and give new perspectives for functionalization of a metallic coating with nanomaterials.
Locating more peaks and refining the solution accuracy on the found peaks are two challenging issues in solving multimodal optimization problems (MMOPs). To deal with these two challenges, a ...distributed individuals differential evolution (DIDE) algorithm is proposed in this article based on a distributed individuals for multiple peaks (DIMP) framework and two novel mechanisms. First, the DIMP framework provides sufficient diversity by letting each individual act as a distributed unit to track a peak. Based on the DIMP framework, each individual uses a virtual population controlled by an adaptive range adjustment strategy to explore the search space sufficiently for locating a peak and then gradually approach it. Second, the two novel mechanisms named lifetime mechanism and elite learning mechanism (ELM) cooperate with the DIMP framework. The lifetime mechanism is inspired by the natural phenomenon that every organism will gradually age and has a limited lifespan. When an individual runs out of its lifetime and also has good fitness, it is regarded as an elite solution and will be added to an archive. Then the individual restarts a new lifetime, so as to bring further diversity to locate more peaks. The ELM is proposed to refine the accuracy of those elite solutions in the archive, being efficient in dealing with the solution accuracy issue on the found peaks. The experimental results on 20 multimodal benchmark test functions show that the proposed DIDE algorithm has generally better or competitive performance compared with the state-of-the-art multimodal optimization algorithms.
In contrast to the kinetically favored outward isomerization‐hydrocarbonylation of alkenes, the disfavored inward isomerization‐hydrocarbonylation of alkenes remains an important challenge. Herein, ...we have developed a novel and effective palladium‐catalyzed inward isomerization‐hydroaminocarbonylation of unactivated alkenes and aniline hydrochlorides for the formation of synthetically valuable α‐aryl carboxylic amides in high yields and high site‐selectivities. The high efficiency of the reaction is attributed to a relay catalysis strategy, in which the Markovnikov‐favored PdH‐PtBu3 catalyst is responsible for inward isomerization, while the PdH‐Ruphos catalyst is responsible for hydroaminocarbonylation of the resulting conjugated aryl alkenes. The reaction exhibits highly functional group tolerance and provides a new method for formal carbonylation of remote C(sp3)−H bond.
A novel palladium‐catalyzed inward isomerization and hydraminocarbonylation of unactivated alkenes for the synthesis of α‐aryl carboxylic amides has been developed. The combination isomerization‐responsible catalyst and hydrocarbonylation‐responsible catalyst was found to be a highly effective strategy to render the reaction feasible. The reaction shows highly functional group compatibility and site‐selectivity.
•An entire population is divided into many parallel evolved sub-swarms in the early stage.•A dynamic sub-swarm number strategy (DNS) periodically reduces the number of sub-swarms aiming to balance ...the exploration and the exploitation ability.•A sub-swarm regrouping strategy (SRS) regrouping these sub-swarms based on the stagnancy information of the globally best position is adopted to enhance the exploitation ability.•A purposeful detecting strategy (PDS) relying on some historical information of the search process is selected to help the population to jump out of the current local optimum for better exploration ability.•The strategies proposed in this paper have general applicability.
This paper proposes a multi-swarm particle swarm optimization (MSPSO) that consists of three novel strategies to balance the exploration and exploitation abilities. The new proposed MSPSO in this work is based on multiple swarms framework cooperating with the dynamic sub-swarm number strategy (DNS), sub-swarm regrouping strategy (SRS), and purposeful detecting strategy (PDS). Firstly, the DNS divides the entire population into many sub-swarms in the early stage and periodically reduces the number of sub-swarms (i.e., increase the size of each sub-swarm) along with the evolutionary process. This is helpful for balancing the exploration ability early and the exploitation ability late, respectively. Secondly, in each DNS period with special number of sub-swarms, the SRS is to regroup these sub-swarms based on the stagnancy information of the global best position. This is helpful for diffusing and sharing the search information among different sub-swarms to enhance the exploitation ability. Thirdly, the PDS is relying on some historical information of the search process to detect whether the population has been trapped into a potential local optimum, so as to help the population jump out of the current local optimum for better exploration ability. The comparisons among MSPSO and other 13 peer algorithms on the CEC2013 test suite and 4 real applications suggest that MSPSO is a very reliable and highly competitive optimization algorithm for solving different types of functions. Furthermore, the extensive experimental results illustrate the effectiveness and efficiency of the three proposed strategies used in MSPSO.
Bound, antibound and resonance states are associated to poles in the on-shell partial wave amplitudes. We show here that from the residues of the pole a rank 1 projection operator associated with any ...of these states can be extracted, in terms of which a sum rule related to the composition of the state can be derived. Although typically it involves complex coefficients for the compositeness and elementariness, except for the bound state case, we demonstrate that one can formulate a meaningful compositeness relation with only positive coefficients for resonances whose associated Laurent series in the variable s converges in a region of the physical axis around Re s sub(P) with s sub(P)the pole position of the resonance. It is also shown that this result can be considered as an analytical extrapolation in s sub(P)of the clear narrow resonance case. We exemplify this formalism to study the two-body components of several resonances of interest.
A binder‐free efficient MoNi4/MoO3‐x nanorod array electrode with 3D open structure is developed by using Ni foam as both scaffold and Ni source to form NiMoO4 precursor, followed by subsequent ...annealing in a reduction atmosphere. It is discovered that the self‐templated conversion of NiMoO4 into MoNi4 nanocrystals and MoO3‐x as dual active components dramatically boosts the hydrogen evolution reaction (HER) performance. Benefiting from high intrinsic activity, high electrochemical surface area, 3D open network, and improved electron transport, the resulting MoNi4/MoO3‐x electrode exhibits a remarkable HER activity with extremely low overpotentials of 17 mV at 10 mA cm−2 and 114 mV at 500 mA cm−2, as well as a superior durability in alkaline medium. The water–alkali electrolyzer using MoNi4/MoO3‐x as cathode achieves stable overall water splitting with a small cell voltage of 1.6 V at 30 mA cm−2. These findings may inspire the exploration of cost‐effective and efficient electrodes by in situ integrating multiple highly active components on 3D platform with open conductive network for practical hydrogen production.
A MoNi4/MoO3‐x nanorod array with dual active components is developed by self‐templated conversion from NiMoO4 host nanorods, which exhibits boosted activity and remarkable durability for hydrogen evolution with extremely low overpotential of 114 mV at 500 mA cm−2 in 1 M KOH. The assembled water–alkali electrolyzer outputs a current density of 30 mA cm−2 at 1.6 V over long‐term operation.
The recently discovered fully charmed tetraquark candidate X(6900) is analyzed within the frameworks of effective-range expansion, compositeness relation and width saturation, and a coupled ...multichannel dynamical study. By taking into account constraints from heavy-quark spin symmetry, the coupled-channel amplitude including the J/ψJ/ψ, χc0χc0, and χc1χc1 is constructed to fit the experimental di-J/ψ event distributions around the energy region near 6.9 GeV. Another dynamical two-coupled-channel amplitude with the J/ψJ/ψ and ψ(3770)J/ψ is also considered to describe the same datasets. The three different theoretical approaches lead to similar conclusions that the two-meson components do not play dominant roles in the X(6900). Our determinations of the resonance poles in the complex energy plane from the refined coupled-channel study are found to be consistent with the experimental analyses. The coupled-channel amplitudes also have another pole corresponding to a narrow resonance X(6825) that we predict sitting below the χc0χc0 threshold and of molecular origin. We give predictions to the line shapes of the χc0χc0 and χc1χc1 channels, which could provide a useful guide for future experimental measurements.
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