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In this paper, the authors present the electrostrictive energy conversion ability of cellular electrets after the high-voltage corona polarization. Moreover, the electrostrictive effect of such foamed polymer before and after corona polarization has also been compared and discussed. The enhancement of electrostrictive effect of cellular electrets after corona polarization was observed. In particular, the impact on the electrostrictive effect of the macroscopic electric dipoles inside of cellular polymer which are generated by high-voltage corona poling procedure has been investigated. The present research has promoted the development of the application of electret in the field of energy conversion, actuator, transducers, etc.

We have successfully converted large volume Al particles into γ-Al₂O₃ nanostructures by vibration milling at room temperature and successive treatment. We show that there exist special relationships among stacking fault energy (SFE), strain energy (SRE), and surface energy (SE) of the materials, including interdependence, intercompetition, and interconversion during the phase transition. SFE and SRE perform the same changing tendency, while SE just does the opposite. However, it is not the particle size but the energy state that determines the reactivity of the materials. And it is the SE that can directly determine the physical chemical reaction and the conversion into the end product rather than SFE and SRE. When SE goes up, the material reactivity and the product yield will be enhanced; and when SE goes down, the reaction and the product yield will decay. However, the state of SE depends closely on the change tendency of the SFE and SRE. That is, when SFE and SRE goes up, SE will goes down; if SFE and SRE goes down, SE will goes up. It seems that energy conservation law may be followed in a sense in the particle system if the external input keeps constant. The work may be significant for energy conversion in nano-scale and mechanosynthesis of oxide nanoparticles.

The dynamic failure behavior of double-layer-domes subjected to impact is studied numerically through the nonlinear finite element software LS-DYNA. The parameters considered in this work include the mass, velocity, and size of impactor, impact direction, roof weigh, geometric imperfection, rise-to-span ratio, and depth of dome. The dynamic time-history response and energy conversion of the structure are utilized to distinguish between the failure mechanism types. For the cases studied, it is found that failure of the structures falls into one of the three categories: (1) local shear failure, (2) partial progressive failure, and (3) full progressive failure. Non-failure case dominates the dome response when the kinetic energy of the impactor is small enough, and the structure can convert most of the kinetic energy into the strain energy, thereby absorbing the impact. Local shear failure occurs in a double-layer-dome when an impactor with very high kinetic energy strikes the dome. For an impactor striking with a mass of 5 to 300ton and a velocity of 50 to 120m/s, the double-layer-dome studied will suffer from partial progressive failure. Varying mass and velocity of the impactor in the range of 1 to 300ton and 200 to 400m/s, respectively, results in a tendency of the dome to exhibit local shear failure. Although impact direction does not cause a change in the failure mechanism type, there is a reduction in the severity of failure of the system as the impact angle increases. Roof weight has no dominant effect on the failure mechanism of the double-layer-dome. A small initial member imperfection with amplitude 0.001$L$ does not change the progressive failure type. A large member imperfection of 0.01$L$ triggers member buckling and leads to local shear failure of the dome. Except for some loading cases, the change in the rise to span ratio and depth of the dome does not seriously affect the failure mode.

Biological motion and human traffic require energy supply from external sources. We develop here a model for the dynamics of driven entities which includes hydrodynamic interactions in order to adapt the model to the dynamics of swarms moving in dense fluids. Our entities have the ability to use the energy contained in an internal energy depot or an external energy inflow for the acceleration of motion. As a prototype of such entities we study Brownian particles having the ability to take up energy from their environment, to store it in an internal energy depot and to convert internal energy into kinetic energy. The motion of the particles is described by Langevin equations which include a dissipative force term resulting from the driving and equations for the dynamics of the depot. The hydrodynamic interactions are modeled by an Oseen-type tensorial force. It is shown that hydrodynamic interactions lead to the synchronization of the directions of motion leading to several new collective modes of the dynamics, including spontaneous rotations of the swarm.

A new dyad 9(ZnP-P) has been synthesized linking 5,15-bis(4-carboxyphenyl)-10,20-bis(4-nitrophenyl) porphyrin 4(P) and Zn(II) 5-(4-aminophenyl)-10,15,20-tris(4-methoxylphenyl) porphyrin 8(ZnP) by an amide bond. The structural moieties of dyad 9(ZnP-P) present both different singlet state energy and redox properties. Dyad 9 was designed to improve the intramolecular electron transfer capacity. The ZnP moiety bears electron-donating methoxy groups and a zinc ion, while the other porphyrin structure, P, is substituted by electron-withdrawing nitro groups. On the other hand, structure P bears a carboxylic acid group, which is able to benefit from the orientation of dyad 9 adsorbed on the SnO₂ electrode. Absorption spectroscopic studies indicated only a very weak interaction between the chromophores in the ground state. The fluorescence analysis shows that both porphyrin moieties in dyad 9 are strongly quenched and that the quenching increases in a polar solvent. The ZnP moiety acts like an antenna for porphyrin P, but, singlet-singlet energy transfer is not complete. Thermodynamically, dyad 9 presents a high capacity to form the photoinduced charge-separated state, ZnP^·+-P^·-. Dyad 9 sensitizes the SnO₂ electrode and the photocurrent action spectrum closely matches the absorption spectrum, which confirms that light absorption by dyad is the initial step in the charge transfer mechanism. The photocurrent efficiency of dyad 9 is considerably higher than those of porphyrin monomers used as models of ZnP and P structures. Two processes may be contributing to enhance the charge injection efficiency in dyad 9; one involves an antenna effect that produces energy transfer from ZnP to P and the other includes electron transfer from the ZnP moiety to the photooxidizable free-base P. This dyad design, with P in direct contact with the substrate through the free carboxylic acid group, is a promising architecture of organic material for spectral sensitization of semiconductor solar cells.

Numerous are the ways through which phthalocyanines have been put into very good use. The on-going search for new energy storage and conversion systems has made phthalocyanines even prettier as alternatives to metal and metal oxide catalysts because of their lower cost. This review article looks through a very narrow window of the applications of phthalocyanines in batteries and supercapacitors as a means of improving the qualities such as cycle property, energy density, capacity, open circuit voltage, etc, of these devices.

A series of first-row transition metal complexes of tetrakis(pentafluorophenyl)porphyrin (1), denoted as 1-M (M$=$Mn, Fe, Co, Ni, Cu, and Zn), were synthesized and examined as electrocatalysts for the hydrogen evolution reaction (HER). All these transition metal porphyrins were shown to be active for HER in acetonitrile using trifluoroacetic acid (TFA) as the proton source. The molecular nature and the stability of these metal porphyrins when functioning as HER catalysts were confirmed, and all catalysts gave Faradaic efficiency of >97% for H₂ generation during bulk electrolysis. Importantly, by using 1-Cu, a remarkably high turnover frequency (TOF) of 48500 s${}^{-1}$1-Cu the most efficient among this series of metal porphyrin catalysts. This TOF value also represents one of the highest values reported in the literature. In addition, electrochemical analysis demonstrated that catalytic HER mechanisms with these 1-M complexes are different. These results show that with the same porphyrin ligand, the change of metal ions will have significant impact on both catalytic efficiency and mechanism. This work for the first time provides direct comparison of electrocatalytic HER features of transition metal complexes of tetrakis(pentafluorophenyl)porphyrin under identical conditions, and will be valuable for future design and development of more efficient HER electrocatalysts of this series.

Ternary nickel cobaltite nanostructures have found their application in many optoelectronic devices due to their excellent electronic and catalytic properties. In this review paper, we will discuss two synthetic strategies for ternary nickel cobaltite nanostructures: nickel cobaltite nanopowders and conductive substrate supported nickel cobaltite, respectively. Then selected examples utilizing ternary nickel cobaltite nanostructures as building blocks for solar cells, photodetectors and water oxidation will be highlighted. In the end, an outlook and conclusion will be given about the future research and development in this field.

Lithium-sulfurized polyacrylonitrile battery is a promising candidate among lithium metal batteries. Nevertheless, the formation of Li dendrites is recognized the worst problem for battery. In this study, we demonstrate an air-stable prelithiation technology for highly reversible Li ion-S@PAN battery. A sandwich-like structure is designed for a lithium–silicon/graphite compound, which not only prevent attack of the lithium surface from humid air, but also improve the lithiation progress more convenient and reliable. When test in Li ion-sulfurized polyacrylonitrile battery, a specific capacity up to 560mAh${\text{g}}^{-1}$, and only 24% capacity loss is witnessed after 1500 cycles at 1000mA${\text{g}}^{-1}$.

When a concentrated salt solution and a diluted salt solution are separated by an ion-selective membrane, cations and anions would diffuse at different rates depending on the ion selectivity of the membrane. The difference of positive and negative charges at both ends of the membrane would produce a potential, called the diffusion potential. Thus, electrical energy can be converted from the diffusion potential through reverse electrodialysis. This study demonstrated the fabrication of an energy conversion microchip using the standard micro-electromechanical technique, and utilizing Nafion junction as connecting membrane, which was fabricated by a surface patterned process. Through different salinity gradient of potassium chloride solutions, we experimentally investigated the diffusion potential and power generation from the microchip, and the highest value measured was 135 mV and 339 pW, respectively. Furthermore, when the electrolyte was in pH value of 3.8, 5.6, 10.3, the system exhibited best performance at pH value of 10.3; whereas, pH value of 3.8 yielded the worst.

The mutual interaction between spin current and magnetization is a key phenomenon in spintronics. This interaction leads to a spinmotive force, a mechanism of energy-transfer from magnetization into conduction electrons. In this paper, the basic concepts and recent developments of the spinmotive force are introduced.

Antiferroelectric (AFE) materials with adjacent dipoles oriented in antiparallel directions have a double polarization hysteresis loops. An electric field (E-field)-induced AFE–ferroelectric (FE) phase transition takes place in such materials, leading to a large lattice strain and energy change. The high dielectric constant and the distinct phase transition in AFE materials provide great opportunities for the realization of energy storage devices like super-capacitors and energy conversion devices such as AFE MEMS applications. Lots of work has been done in this field since 60–70 s. Recently, the strain tuning of the spin, charge and orbital orderings and their interactions in complex oxides and multiferroic heterostructures have received great attention. In these systems, a single control parameter of lattice strain is used to control lattice–spin, lattice–phonon, and lattice–charge interactions and tailor properties or create a transition between distinct magnetic/electronic phases. Due to the large strain/stress arising from the phase transition, AFE materials are great candidates for integrating with ferromagnetic (FM) materials to realize in situ manipulation of magnetism and lattice-ordered parameters by voltage. In this paper, we introduce the AFE material and it's applications shortly and then review the recent progress in AFEs based on multiferroic heterostructures. These new multiferroic materials could pave a new way towards next generation light, compact, fast and energy efficient voltage tunable RF/microwave, spintronic and memory devices promising approaches to in situ manipulation of lattice-coupled order parameters is to grow epitaxial oxide films on FE/ferroelastic substrates.

Coatings provide underlying item surfaces or bulk materials with protection, enhancement, and/or additional usefulness and attributes. Since materials can be modified or enhanced to possess different properties such as mechanical, thermal, or chemical to improve urban built environment functions, nanotechnologies have been widely included in functional coatings in recent years. Recent studies on functional coatings for green and smart buildings are summarized in this review paper. These comprised phase change materials, photocatalytic, hydrophilic, hydrophobic, solar reduction, and solar utilization coatings. This study offers a thorough overview of functional coating methods, from the production of raw materials through their application to building components.

The increasing environmental pollution and serious shortage of energy and resources have become big problems in human society in the recent years. Exploration of novel renewable and biodegradable materials based on biomass and construction of biomass-based energy-related applications have received more and more attention. Cellulose is the most abundant biomass on earth. Especially, nanocellulose possesses excellent mechanical, thermal, and optical properties. In this chapter, we review the recent advances in nanocellulose-based energy conversion materials, including piezoelectric materials, loudspeakers, antenna, phototransistors, organic light-emitting diodes (OLEDs), and touch screen.

As the global population continues to increase, so does the demand for energy. It is unlikely that this increased demand can be met by the ubiquitous fossil fuel sources alone and, therefore, the use of other energy sources will need to expand. Fortunately, there are numerous sources of energy and many different methods for converting that energy into useful forms, like electricity. Indeed, the United Nations is seeking to increase access to electricity by all people as part of their overarching goal to eliminate global poverty. At the same time, because of the projections and observations surrounding climate change models, the elimination of fossil fuels, and their “harmful” atmospheric emissions, has been promoted. Fossil fuels would be replaced by sustainable and renewable energy sources such as solar and wind power. Some of the richer countries, like Germany and Denmark, have already acted vigorously on such replacements. However, the largest users of energy and producers of emissions still only obtain a small, but increasing, percentage of their energy from nonrenewable sources. Moreover, despite the laudable United Nations (UN) goals, and those of the “Paris Agreement” over a third of the global population cannot access clean cooking fuels, and many millions still live in abject poverty. In such circumstances is it possible to have a global agreement on a universally acceptable energy mix, which includes a complete transition away from fossil fuels? If not, what are the alternatives? These questions are explored in this chapter.

Coatings provide underlying item surfaces or bulk materials with protection, enhancement, and/or additional usefulness and attributes. Since materials can be modified or enhanced to possess different properties such as mechanical, thermal, or chemical to improve urban built environment functions, nanotechnologies have been widely included in functional coatings in recent years. Recent studies on functional coatings for green and smart buildings are summarized in this review paper. These comprised phase change materials, photocatalytic, hydrophilic, hydrophobic, solar reduction, and solar utilization coatings. This study offers a thorough overview of functional coating methods, from the production of raw materials through their application to building components.