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Advanced electromagnetic (EM) wave absorbers with wide bandwidth is crucial to avoid EM interference and radiation, while achieving compensational attenuation at different frequencies is challenging. Herein, two-dimensional (2D) sandwiched FeNi@SnO2 have been designed, for which SnO2 nanosheets provide numerous heterogeneous nucleation sites for the growth of dispersive FeNi nanoparticles with reduced size. The SnO2 exhibits dipole polarization at 21.45 GHz with a width of ∼4.00 GHz, while the FeNi nanoparticles induce exchange resonance at 18.13 GHz (∼6.00 GHz width) and interfacial polarization at 15.97 GHz (∼6.00 GHz width). Such complementary attenuation mechanisms give rise to an impressive ultra-wide effective absorption bandwidth of 11.70 GHz with strong absorption of -49.1 dB at a small thickness of 1.75 mm. Not only superior EM wave absorption is achieved in this work, it also provides a versatile strategy to integrate different loss mechanisms in the design of EM wave absorbers with extra-wide bandwidth.

Listeria monocytogenes (L. monocytogenes) is one of the top five dangerous foodborne pathogens which widely exists in most raw food and has approximately 30 % mortality rate in high-risk groups. Food safety caused by foodborne pathogens is still a major problem faced by humans in all world. The conventional analytical methods currently used involve complex bacteriological tests and usually take several days for incubation and analysis. Thus, in order to prevent the spread of disease, the development of a detection method with high speed, high accuracy and sensitivity is urgent and necessary. Herein, we developed an approach for the identification and magnetic capture of L. monocytogenes by using core@shell Fe3O4@silica nanoparticles terminated with hydroxyl or amine groups. Our results show that both amine- and hydroxyl-terminated Fe3O4@silica core@shell nanoparticles functionalized with specific antibodies, present 95.2 %±6.2 % and 98.6 %±0.3 % capture efficacies, respectively. However, without conjugating the specific antibodies, the hydroxyl-terminated Fe3O4@silica nanoparticles exhibit 17.6 %±1.6 % efficacy, while the amine-terminated one remains 93.2 %±9.2 % capture efficiency ascribed to the high affinity. This study quantitatively uncovers the specific and non-specific recognitions relevant to the molecular-scale physiochemical interactions between the microorganisms and the functionalized particles, and the results from this work can be generalized and extended to other bacterial species by changing antibodies, also have important implications in developing advanced analytic methods.

Syngas from biomass gasification is being developed for alternative feedstock in the chemical industry. Palm kernel shell which is generated from palm oil industry can be potentially used as raw material for gasification process. The purpose of this study was to investigate the use of modified natural zeolite catalysts in steam gasification of palm kernel shells. Mordenite type zeolite was modified by acid leaching to be used as a tar cracking catalyst. Steam gasification was conducted at the temperature range of 750–850 °C and the steam to biomass ratio was in the range of 0–2.25. The result showed that steam gasification of palm kernel shell with the addition of zeolite catalyst at 750 °C and steam to biomass ratio 2.25 could reduce tar content up to 98% or became 0.7 g/Nm3. In this study, gasification of palm kernel shells produced syngas with the hydrogen concentration in the range of 52–64% and H2/CO ratio of 2.7–5.7. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Anisotropy engineering serves as an effective method to achieve unique properties and enhanced performance of materials. Here MOF-71 and derivatives with tuned anisotropy have been achieved via facial tuning the proticity of the solvents, giving rise to nanoflake assemblies into bellows-, boat- and flower-like microstructures. Three anisotropy dimensions including Faceting, Aspect ratio and Arrangement have been proposed to describe the anisotropy of the assemblies, which are further evaluated by heterotype ( H ¯ ), flatness ( F ¯ ) and orderliness ( O ¯ ). Combined off-axis electron holography and electromagnetic scattered field simulation visualize uniform distribution of magnetic lines due to enhanced anisotropy of the bellows-like derivatives. This gives rise to strengthened magnetic loss and electromagnetic wave absorption for the anisotropy evolution from the flower-, boat-to bellows-like structure. As such the work not only provides versatile strategy for anisotropy engineering and reification of the anisotropy for complicated assembled structures, but also insights on impacts of the anisotropy on the distribution of stray field, magnetic dipoles and scattered field for the design of electromagnetic absorbers, which are extendable to various areas including but not limited to magnetics, electrics and optics.

MnZn soft magnetic ferrites have been widely utilized in power electronics, owing to the combined merits of high permeability and low energy loss. However, their deployment would result in a drastic increase in power dissipation at >3 MHz, thus limiting the scope extent of miniaturization, together with their efficiency. Here, we report a high-performance MnZn ferrite by doping multiple ions (La, Ti, Si, Ca) at grain boundaries, achieving the most optimized power loss of 267 kW/m3 at 5 MHz (10 m T, 100 °C) and initial permeability of 644, which is much better than the previously reported results and commercial products. Such an improvement is attributed to weakened magnetic exchange coupling at grain-boundary regions, associated with a significant transition from the multi- to mono-domain structures, originating physically from large crystallographic mis-orientations (>25°). The present study bears important significance in understanding the intrinsic correlation between the crystallographic mis-orientation and magnetic domain structure, and provides an alternative way for optimizing high-frequency soft magnetic ferrites.

Parabolic dish solar collectors gain higher solar to thermal conversion efficiency due to their maximum concentration ratio. The present research focuses by integrating the parabolic dish solar collector to the steam cycle producing power and rate of process heating. Pressurized water, therminol VP1, and supercritical carbon dioxide are the examined working fluids in the parabolic dish solar collector. The aim of the current research is to observe the optimal operating conditions for each heat transfer fluid by varying inlet temperature and flow rate of the working fluid in the parabolic dish solar collector, and combination of these parameters is predicted to lead to the maximum energy and exergy efficiencies of the collector. The operating parameters are varied to investigate the overall system efficiencies, work output, and process heating rate. Findings of the study declare that water is an efficient heat transfer fluid at low temperature levels, whereas therminol VP1 is effective for a higher temperature range. The integrated system efficiencies are higher at maximum flow rates and low inlet temperatures. The efficiency map of solar collector is located at the end of study, and it shows that maximum exergy efficiency gains at inlet temperature of 750 K and it is observed to be 37.75%.

The formation of ordered magnetic domains in thin films is important for the magnetic microdevices in spin-electronics, magneto-optics, and magnetic microelectromechanical systems. Although inducing anisotropic stress in magnetostrictive materials can achieve the domain assembly, controlling magnetic anisotropy over microscale areas is challenging. In this work, we realized the microscopic patterning of magnetic domains by engineering stress distribution. Deposition of ferromagnetic thin films on nanotrenched polymeric layers induced tensile stress at the interfaces, giving rise to the directional magnetoelastic coupling to form ordered domains spontaneously. By changing the periodicity and shape of nanotrenches, we spatially tuned the geometric configuration of domains by design. Theoretical analysis and micromagnetic characterization confirmed that the local stress distribution by the topographic confinement dominates the forming mechanism of the directed magnetization.

In order to study the transformation and distribution of sulfur element during supercritical water gasification (SCWG) of sewage sludge, sulfur contained products in different phase were detected in batch reactor. The XPS analysis showed that organic sulfur was the main part of sulfur compounds in sewage sludge. On the other hand, inorganic sulfur was dominated by SiS2, and SiS2 was subsequently converted into SiO2 and H2S during SCWG. The increase of temperature promoted H2S and SO2 yield but reduced their concentration. The addition of KOH could reduce the yield and concentration of H2S and SO2. The minimum concentration of H2S and SO2 was observed at 450 °C with KOH addition, which was 1313.94 ppm and 698.03 ppm, respectively. Sulfur compound in liquid was mainly found in the form of sulfate and its concentration decreased with increasing temperature.

RDF made of municipal solid waste was pyrolyzed under simulated pyrolytic gas (PG) atmosphere and N2 atmosphere. Besides pyrolysis temperature, the atmosphere also affected the yield of three phase products and thermal conversion. By comparison of the products from two different atmospheres at same pyrolysis temperature, more tar, less char and gas were produced under PG atmosphere than the yields produced under N2 atmosphere; LHV of char produced under PG atmosphere was always lower than the value of char produced under N2 atmosphere, so that the char thermal conversion (CTC) efficiency under PG atmosphere also was lower; O/C and H/C of chars produced PG atmosphere were usually smaller than the data of char produced under N2 atmosphere, which indicated chars produced under PG atmosphere were more similar with coal, and more suitable for co-combustion of coal and char in coal power plant. In additional, highest comprehensive combustion characteristic index S was obtained at 600 °C under PG atmosphere. LHV of gas produced under PG atmosphere was always higher than the gas produced under N2 atmosphere, but gas thermal conversion (GTC) efficiency under PG atmosphere was lower because of less gas yield.

Multi-camera target tracking is a research hot spot in the field of computer vision. Because the field of view covered by the fixed monocular camera is limited, it cannot continuously track fast-moving targets for a long time, such as the video sequence of skaters’ short-track speed skating. However, for such video sequences, the relative displacement of target between frames is relatively large and the advanced tracking algorithm is difficult to achieve accurate tracking, which has a considerable impact on the subsequent target handover. In view of this situation, we use four fixed cameras to build a tracking system to continuously track skater and propose to use convolutional neural network to extract the semantic features of the target to improve the accuracy of the target handover process. Aiming at this kind of fast motion video sequence with a fixed field of view, a new tracking algorithm was proposed. We establish the motion model of the target and integrate the speed information of the target into the sample generation mechanism. In addition, we also construct a scale filter in context to constantly and iteratively update the scale change information of the prediction box to adapt to the significant change of the visual properties of the target. It improves the stability and robustness of the system. Extensive experimental results in object tracking benchmark and our dataset of skaters illustrate outstanding performance of our method compared with the state-of-the-art methods, especially against the fast motion sequences with a fixed field of view.

RE2Fe14B-based (RE, rare earth) permanent magnets containing abundant and cheap La/Ce have attracted intense attention recently. In comparison with Ce that can fully replace Nd in the 2:14:1 lattice, La substitution for Nd has long been limited at a low level. Here we present that through doping La35Ce65 alloy with the La/Ce ratio in natural mineral, stable 2:14:1 phase can be maintained at 1273 K within the entire substitution range of [(La35Ce65)x(Pr20Nd80)1-x]2.14Fe14B (0.6 ≤ x ≤ 1.0, at.%), as verified by composition analysis, microstructural characterization and magnetic measurements. Interestingly, the promoted La solution in 2:14:1 phase induces two unique findings upon coexisting La-Ce-Pr-Nd: i) Compared to Ce that fits well with the nominal concentration, La deviates noticeably from the nominal one; ii) Nanoscale spinodal-decomposition-like phase separation is observed due to different solubilities of La-Ce-Pr-Nd elements in 2:14:1 phase. Above joint effects induce higher Curie temperature than estimation based on the rule of mixture, which delights the prospect of La35Ce65 alloy in developing low-cost permanent materials.

With the growth of chemical data, computation power and algorithms, machine learning-assisted high-throughput virtual screening (ML-assisted HTVS) is revolutionizing the research paradigm of new materials. Herein, a combined ML-assisted HTVS and experimental approach was applied to accelerate the search for energetic melt-castable materials with promising properties. The ML-assisted HTVS system is composed of high-throughput molecular generation (in a heuristic enumeration method) and five machine learning-based property prediction models (including density, melting point, decomposition temperature, detonation velocity, and detonation pressure). Using this system, we rapidly targeted 136 promising candidates from a generated molecular space containing 3892 molecules. With extensive efforts on experimental synthesis, eight new energetic melt-castable materials (MC-1 to MC-8) were obtained, and their measured properties were in good agreement with the predicted results. This work verifies the effectiveness of the combined ML-assisted HTVS and experimental approach for the accelerated discovery of energetic melt-castable materials.

The chain-like carbon nanotubes (CNTs) decorated with CoFeB (CoFeB/CNTs) prepared by oxidation-reduction method is introduced into MgH2 to facilitate its hydrogen storage performance. The addition of CoFeB/CNTs enables MgH2 to start desorbing hydrogen at only 177 °C. Whereas pure MgH2 starts hydrogen desorption at 310 °C. The dehydrogenation apparent activation energy of MgH2 in CoFeB/CNTs doped-MgH2 composite is only 83.2 kJ/mol, and this is about 59.5 kJ/mol lower than that of pure MgH2. In addition, the completely dehydrogenated MgH2−10 wt% CoFeB/CNTs sample can start to absorb hydrogen at only 30 °C. At 150 °C and 5 MPa H2, the MgH2 in CoFeB/CNTs doped-MgH2 composite can absorb 6.2 wt% H2 in 10 min. The cycling kinetics can remain rather stable up to 20 cycles, and the hydrogen storage capacity retention rate is 98.5%. The in situ formation of Co3MgC, Fe, CoFe and B caused by the introduction of CoFeB/CNTs can provide active and nucleation sites for the dehydrogenation/rehydrogenation reactions of MgH2. Moreover, CNTs can provide hydrogen diffusion pathways while also enhancing the thermal conductivity of the sample. All of these can facilitate the dehydrogenation/rehydrogenation performance and cyclic stability of MgH2.

Sub- and supercritical water gasification is applied to recover energy from sewage sludge in a batch reactor. The effects of reaction temperature and water-soluble additives as catalysts on gasification were examined. The resultant products, including syngas, hydrochar and liquid residues were characterized. The rise of temperature without the presence of catalysts increased the yield of H2 (0.06 (350 °C) to 1.91 mol/kg (450 °C) and enhanced the gasification efficiency (1.29–19.61%), and decreased total organic carbon (TOC) by 68.50% in liquid residue. The changes in product distribution and characteristics of hydrochar and liquid residue implied that the organic matters in sewage sludge were dissolved and hydrolyzed in sub- and supercritical water, resulting in the production of syngas. The catalytic effect of different catalysts in relation to the H2 gas yield was in the following order: KOH > NaOH > Na2CO3 ≈ K2CO3. In the case of catalytic supercritical water gasification at 400 °C, the highest molar fraction (37.28%) and yield of H2 (1.60 mol/kg) were obtained in the presence of KOH. Furthermore, the scanning electron microscopy (SEM) analysis indicated that a conversion and dissolution of the organic matters in sewage sludge to liquid and gas, produced a porous, fragmented structure and disintegrated surface of hydrochar.

The solid-state magnetic cooling (MC) relying on magnetocaloric effect (MCE) of magnetic materials is recognized as a promising energy efficiency and environmentally friendly technology. However, there is still a large gap between the fundamental materials in the laboratory developing stage and the practically realizable applications. In this paper, a new series of B-site ordered RE2ZnMnO6 (RE = Gd, Dy and Ho) perovskites are successfully fabricated, and their structural and magnetic properties together with the cryogenic magnetocaloric performances are studied in detail. All the RE2ZnMnO6 compounds are found to crystallize in the B-site ordered orthorhombic (double perovskites) structure with the space group of P121/C1. The magnetic ground state are confirmed to be a ferromagnetic (FM) coupling for Gd2ZnMnO6, whereas, ferrimagnetic (FIM) coupling for Dy2ZnMnO6 and Ho2ZnMnO6 based on the magnetic measurements and first principle calculations. The ordering temperatures (TM) are determined to be ~6.4 K for Gd2ZnMnO6, ~10.4 K for Dy2ZnMnO6, and ~6.8 K for Ho2ZnMnO6, respectively. Furthermore, several vital parameters for determining the magnetocaloric performances including -ΔSMmax (magnetic entropy change peak values), TEC(2) (temperature-averaged magnetic entropy change) and RCP (relative cooling powers) are evaluted to be 15.17, 14.44 J/(kgK) and 226 J/kg for Gd2ZnMnO6, 8.32, 8.17 J/(kgK) and 208 J/kg for Dy2ZnMnO6, and 13.19, 12.68 J/(kgK) and 246 J/kg for Ho2ZnMnO6, with the field change ΔH = 50 kOe, respectively. It is worthly noted that Gd2ZnMnO6 exhibits relatively great magnetocaloric performances below 10 K, which suggests that Gd2ZnMnO6 is a competitive candidate for cryogenic magnetic cooling.

Waste sorting is being gradually implemented as a key measure for circular and sustainable development in China, food waste will be separately collected and separated from municipal solid waste (MSW), thus the plastic content in food waste also will be reduced. In this study, supercritical water gasification (SCWG) of food waste with different contents of plastic (0–3.5 wt%) was experimentally investigated to simulate the influence of waste sorting on the food waste treatment. The results showed that lower plastic content in food waste favored higher gas yield and gasification efficiencies. The highest H2 yield and total gas yield were 3.11 mol/kg and 8.41 mol/kg in the plastic-free case, respectively. When the plastic content decreased from 3.5 wt% to 0 wt%, the cold gas efficiency (CGE), carbon conversion efficiency (CE) and hydrogen gasification efficiency (HE) increased by 125.97%, 173.48% and 94.09%, respectively. However, lower plastic content negatively affected the quality of produced syngas through decreasing H2 mole fraction and LHV. The solid residues from SCWG of food waste with lower plastic content had higher ratio of fixed carbon to volatile matter (FC/VM). Based on the analysis of pyrolysis properties and combustion behavior, decreasing the plastic content in food waste helped to improve the thermal stability of solid residues. Moreover, lower plastic content resulted in a decrease of total organic carbon (TOC) concentration in liquid effluent, which is favorable for further treatment of liquid effluent.

Massive rare earth oxides inevitably form at high La–Ce substitution, causing inadequate liquid-phase-sintering, direct exchange coupling of ferromagnetic grains, obscure core–shell morphology and severe coercivity degradation of multi-main-phase (MMP) Nd–La–Ce–Fe–B sintered magnets. To fully exploit the abundant La–Ce for application, here we designed a facile approach, (Pr, Nd)Hx grain boundary diffusion that combines the joint benefits of forming thick non-ferromagnetic grain boundary layer and PrNd-rich hardening shell, yielding a nearly threefold coercivity of 14.2 kOe with enhanced energy product of 38.5 MGOe for LaCe-40 magnet. These findings suggest a reliable recipe for relieving the main constraints of MMP Nd–La–Ce–Fe–B magnets.

MnZn power ferrites are technologically important for miniaturization and efficiency of electronic devices. It is of practical significance to obtain high working frequency and temperature in the MnZn ferrites. In this study, MnZn ferrites capable of working above 1 MHz and 80 °C have been successfully prepared by Nb2O5 and TiO2 doping. Nb2O5 promotes the densification process during sintering and exists as a resistive layer in the grain boundary region, leading to improved permeability and power losses. TiO2 doping results in the formation of localized Ti4+-Fe2+ pairs and offers extra cation vacancies for Nb5+ diffusion, which further enhances the effect of Nb2O5. The sample doped with 250 ppm of Nb2O5 and 2500 ppm of TiO2 presents optimal magnetic properties with the lowest power loss value of 394 kW/m3 at 1 MHz and 80 °C , along with an initial permeability of 1510, thus, serving as a good candidate for MHz, high-temperature and high-permeability power applications.

The cracking of real tar obtained from a pilot-scale gasifier of municipal solid waste was studied. The tar was both thermally and catalytically cracked under N2 atmosphere. Thermal cracking experi...

In order to improve the hydrogen storage performance of MgH2, graphene and CeF3 co-catalyzed MgH2 (hereafter denoted as MgH2+CeF3@Gn) were prepared by wet method ball milling and hydriding, which is a simple and time-saving method. The effect of CeF3@Gn on the hydrogen storage behavior of MgH2 was investigated. The experimental results showed that co-addition of CeF3@Gn greatly decreased the hydrogen desorption/absorption temperature of MgH2, and remarkably improved the dehydriding/hydriding kinetics of MgH2. The onset hydrogen desorption temperature of Mg + CeF3@Gn is 232 °C，which is 86 °C lower than that of as-milled undoped MgH2, and its hydrogen desorption capacity reaches 6.77 wt%, which is 99% of its theoretical capacity (6.84 wt%). At 300 °C and 200 °C the maximum hydrogen desorption rates are 79.5 and 118 times faster than that of the as-milled undoped MgH2. Even at low temperature of 150 °C, the dedydrided sample (Mg + CeF3@Gn) also showed excellent hydrogen absorption kinetics, it can absorb 5.71 wt% hydrogen within 50 s, and its maximum hydrogen absorption rate reached 15.0 wt% H2/min, which is 1765 times faster than that of the undoped Mg. Moreover, no eminent degradation of hydrogen storage capacity occurred after 15 hydrogen desorption/absorption cycles. Mg + CeF3@Gn showed excellent hydrogen de/absorption kinetics because of the MgF2 and CeH2-3 that are formed in situ, and the synergic catalytic effect of these by-products and unique structure of Gn.

In China, waste sorting practice is not strictly followed, plastics, especially food packaging, are commonly mixed in food waste. Supercritical water gasification (SCWG) of unsorted food waste was conducted in this study, using model unsorted food waste by mixture of pure food waste and plastic. Different operating parameters including reaction temperature, residence time, and feedstock concentration were investigated. Moreover, the effect of three representative food additives namely NaCl, NaHCO3 and Na2CO3 were tested in this work. Finally, comparative analysis about SCWG of unsorted food waste, pure food waste, and plastic was studied. It was found that higher reaction temperature, longer residence time and lower feedstock concentration were advantageous for SCWG of unsorted food waste. Within the range of operating parameters in this study, when the feedstock concentration was 5 wt%, the highest H2 yield (7.69 mol/kg), H2 selectivity (82.11%), total gas yield (17.05 mol/kg), and efficiencies of SCWG (cold gas efficiency, gasification efficiency, carbon gasification efficiency, and hydrogen gasification efficiency) were obtained at 480 °C for 75 min. Also, the addition of food additives with Na+ promoted the SCWG of unsorted food waste. The Na2CO3 showed the best catalytic performance on enhancement of H2 and syngas production. This research demonstrated the positive effect of waste sorting on the SCWG of food waste, and provided novel results and information that help to overcome the problems in the process of food waste treatment and accelerate the industrial application of SCWG technology in the future.

Prussian blue analogues hold great promise as cathodes in sodium ion batteries. Among Prussian blue analogues, manganese hexacyanoferrate is desirable because of its high working voltage, as well as its high specific capacity and low cost. However, poor cycling stability and unsatisfactory rate capability of manganese hexacyanoferrate, which are mainly caused by poor intrinsic conductivity, phase transition, side reactions, and transition metal dissolution, extremely limit its practical application. In this work, we demonstrate a high-rate and long-life MnHCF@PEDOT sodium ion battery cathode through a facile in situ polymerization method. Benefitting from the synergistic effect of the inhibited Mn/Fe dissolution, suppressed phase transition, and improved capacitive storage, the composite electrode exhibits a high capacity of 147.9 mA h g−1 at 0.1C, 95.2 mA h g−1 at a high rate of 10C, and 78.2% capacity retention after 1000 cycles. Furthermore, even at a low temperature of −10 °C, MnHCF@PEDOT still delivers a high capacity of 87.0 mA h g−1 and maintains 71.5 mA h g−1 (82.2%) after 500 cycles.

The co-gasification of sewage sludge and palm oil empty fruit bunch (EFB) in supercritical water (SCW) was conducted at 400 °C with a pressure of over 25 MPa. This study aimed to investigate the influence of EFB addition on the syngas production and its composition. The heavy metal distribution and the leaching potential of the solid residue were also assessed. The results showed that syngas yield significantly increased with the addition of EFB into the feedstock. The cold gas efficiency (CGE) and carbon efficiency (CE) of co-gasification were higher than those of individual gasification. The actual syngas production from co-gasification of sludge and EFB was 45% higher than the theoretical total volume. The results indicated that the addition of EFB to sludge had the synergetic promotion effect on syngas production from sludge and EFB in supercritical water. This enhancement might be due to the dissolution of alkali metals from EFB and the adjustment of organic ratio. In addition, higher percentage of heavy metals were deposited and stabilized in the solid residue after SCWG. The leaching concentration of heavy metals from the solid residues was decreased to a level below the standard limit which enables it to be safely disposed of in landfill. In conclusion, the EFB addition has been proved to promote syngas production, as well as, stabilize the heavy metal in solid residues during co-SCWG.

Ni/Al2O3 catalyst is the one of promising catalysts for enhancing H2 production from supercritical water gasification (SCWG) of biomass. However, due to carbon deposition, the deactivation of Ni/Al2O3 catalyst is still a serious issue. In this work, the effects of lanthanum (La) as promoter on the properties and catalytic performance of Ni/Al2O3 in SCWG of food waste were investigated. La promoted Ni/Al2O3 catalysts with different La loading content (3–15 wt%) were prepared via impregnation method. The catalysts were characterized using XRD, SEM, BET techniques. The SCWG experiments were carried out in a Hastelloy batch reactor in the operating temperature range of 420–480 °C, and evaluated based on H2 production. The stability of the catalysts was assessed by the amount of carbon deposition on catalyst surface and their catalytic activity after reuse cycles. The results showed that 9 wt% La promoter is the optimal loading as Ni/9La–Al2O3 catalyst performed best performance with the highest H2 yield of 8.03 mol/kg, and H2 mole fraction of 42.46% at 480 °C. La promoted Ni/Al2O3 catalysts have better anti-carbon deposition properties than bare Ni/Al2O3 catalyst, resulting in better gasification efficiency after reuse cycles. Ni/9La–Al2O3 catalyst showed high catalytic activity in SCWG of food waste and had good stability as it was still active for enhancing H2 production when used in SCWG for the third time, which indicated that La promoted Ni/Al2O3 catalysts are potential additive to improve the SCWG of food waste.

The integrated gasification combined cycle (IGCC) has been applied as an alternative technology for power plant due to the higher thermal efficiency than that of conventional pulverized coal-fired ...

The potential of sewage sludge for hydrogen-rich syngas production from supercritical water gasification (SCWG) was evaluated through thermodynamic analysis and experimental work. The thermodynamic analysis was conducted by using Aspen Plus simulator based on Gibbs free energy minimization. The effect of temperature (380–460 °C), sludge concentration (5–30 wt%), and activated carbon addition (2–8 wt%) on SCWG was experimentally studied. The solid and liquid residues were characterized by Fourier Transform Infrared (FTIR) spectroscopy, Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), and Total Organic Carbon (TOC) Analyzer. The results showed that higher temperature and lower sludge concentration favored syngas production, leading to higher hydrogen yield. While pressure had no significant effect on the SCWG performance. The TOC and FTIR analyses revealed that organic matters in sewage sludge were decomposed and hydrolyzed into syngas. The addition of activated carbon increased the syngas yield and enhanced the cold gas efficiency. A syngas yield of 6.44 mol/kg containing 38.43% H2 was obtained from SCWG at 400 °C with the activated carbon loading of 8 wt%. Moreover, the analysis of heavy metals indicated that SCWG had a positive effect on the stabilization of heavy metals and reduced the leaching toxicity of heavy metals in sewage sludge.

Rechargeable aqueous Zn-ion battery has been considered as a key complement to the existing battery technologies due to its intrinsic merits such as operational safety and cost saving. However, issues of dendrite growth and accompanied water consumption hinder its further development. In this work, we utilize a chelating agent, 2-Bis(2-hydroxyethyl) amino-2-(hydroxymethyl)-1,3-propanediol (BIS-TRIS), to regulate the solvation sheath structure of Zn2+. Benefiting from such zinc-chelating coordination, Zn2+ 2D diffusion can be restricted and the altered deposition kinetic has contributed to the inhibition of the dendrite growth. In addition, partial substitution of water in solvation shell with chelator can also greatly suppress the competitive hydrogen evolution reaction (HER). Consequently, a stable symmetric Zn cell with lifetime more than 1000 h at a current density of 1 mA cm−2 is achieved. Moreover, the aqueous Zn/MnO2 battery with BIS-TRIS as electrolyte additive delivers an 86% capacity retention after 600 cycles at 500 mA g−1. This zinc-chelating coordination based facile strategy opens a new window for the future development in dendrite-free Zn anode.

Thermal protection systems (TPSs) and drag reduction have already garnered considerable attention in the field of hypersonic vehicles, and numerous research efforts have aimed to develop ac...

Two-dimensional metal-organic frameworks (2D-MOFs) and their derivatives are promising for catalysis, energy storage, gas separation, etc. due to their unique microstructure and physicochemical properties. Many efforts have been devoted to fabricating 2D-MOFs with challenges remaining in yield and fine control of their thickness and lateral size. Here a versatile strategy has been used involving epitaxial, anisotropic, and confined growth of CoNi-MOF-71 nanosheet arrays, giving rise to excellent quantity and controllability of the 2D-MOFs. Electromagnetic (EM) wave absorption performance has been investigated for the resultant 2D Co/Ni/C derivatives. Compared with the bulk counterpart, significantly increased surface area, conductivity, and shape anisotropy for the 2D derivatives result in enhanced interfacial polarization, conductive loss, and magnetic resonance. As such, optimum EM wave absorption of minimum reflection loss RLmin = -49.8 dB and an ultrawide effective adsorption bandwidth EAB = 7.6 GHz can be achieved at a thickness of 2.6 mm. This work not only sheds light on the performance enhancement for 2D absorbers via synergistic effects of multiple attenuation mechanisms but also provides an effective fabrication route of ultrathin MOFs with high yield and uniform size for extended applications in catalysis, electrochemistry, and optoelectronics fields.

Cross-linking network structures are critical to construct flexible and lightweight electromagnetic (EM) wave absorbers, for which effective regulation of the EM parameters is essential. Herein, a versatile strategy has been developed by interconnecting carbon fibers with NiFe-layered double hydroxide (NiFe LDH)/MXene derivatives. The large-sized flaky morphology and conductive nature of the interconnectors induce the percolation effect in the fabric networks with ultralow addition. As such, efficient adjustment of the EM parameters can be achieved by tuning the content of the interconnectors around the percolation threshold, giving rise to an optimal reflection loss (RL) of -58.0 dB and a wide effective absorption band (EAB) of 7.0 GHz at a thickness of 2.5 mm under the incorporation of 7.0 wt % NiFe LDH/MXene. This work provides insights on constructing percolation networks and effective manipulation of electronic and magnetic properties, which can be extended to various areas such as sensing, catalysis, and energy storage.

REFe2 (RE = rare earth) phase has been considered to form spontaneously in Nd-Ce-Fe-B cast strips and inherit into sintered magnets. However, here we report that REFe2 phase, which is absent in starting strip, occurs in as-sintered magnet with an identical composition of 25 wt% Ce. More interestingly, the formation of REFe2 induces apparent Ce-enriched shell surrounding RE2Fe14B grain, which is further exacerbated in annealed magnet containing a higher fraction of REFe2 phase. Influences of increasing REFe2 fraction on magnetic performance are revealed. Above findings on REFe2 phase evolution and resultant Ce segregation may shed lights on fabricating high-performance Nd-Ce-Fe-B.

An integrated system of supercritical water gasification (SCWG) and combined cycle has been developed for H2 production and power generation. Sewage sludge and lignite coal were selected as raw material in this simulation. The effects of feed concentration (10–30 wt%) and lignite coal addition (0–50 wt%) on syngas yield and H2 yield were also investigated in the temperature range of 500 °C–700 °C. Several heat exchangers were considered in the proposed integrated system to minimize energy loss. High pressure syngas was expanded by using turbo-expander to produce electricity, resulting in the improvement of the total efficiency. The results showed that the minimum feed concentrations of 14.25 wt%, 18.75 wt%, and 25.50 wt% were required to achieve self-sufficient energy at 500 °C, 600 °C, and 700 °C, respectively. However, the lower feed concentration and higher temperature were preferable for syngas production. The highest syngas and H2 yield were obtained at 700 °C and 10 wt% feed concentration. The SCWG could produce 178.08 kg syngas from 100 kg feed and 9.06 kg H2 were obtained after H2 separation. The total power generation from turbo-expander and combined cycle module was 48.37 kW. By combining SCWG and combined cycle, the total efficiency could reach 63.48%. It worth mentioning that the addition of lignite coal could help reduce the minimum feed concentration to achieve autothermal condition, but did not have significant improvement on H2 production.

The efficient production of high calorific value solid fuel from palm oil empty fruit bunch (EFB) was investigated by experimenting hydrothermal carbonization (HTC) with initial absolute pressures of 0.1 MPa, 1.3 MPa, and 3.1 MPa in N2 atmosphere and in CO2 atmosphere. The pressure increase in HTC is expected to promote the improvement of calorific value in efficient way, while the alteration of reaction atmosphere from N2 to CO2 is aimed at obtaining higher extent of carbonization. Increasing the initial pressure of N2 improved calorific value of the derived fuel from 19.3 MJ/kg to 22.2 MJ/kg, while creating only trivial effect on energy yield. Increasing the initial pressure of CO2 further enhanced the carbonization and resulted in fuel with maximum calorific value of 23.6 MJ/kg. However, it also resulted in up to 6% reduction on energy yield compared with the cases with N2. The advantages of pressurized HTC in N2 atmosphere and in CO2 atmosphere over conventional HTC were evident when used for the production of fuels with comparable heating value. Process efficiencies of the pressurized HTC in both N2 and CO2 atmospheres were shown to be 4–8% higher than those of conventional HTC with normal initial reaction pressure.

Advanced electromagnetic (EM) wave absorbing materials containing both magnetic and dielectric components have attracted considerable attention for the ever-developing electronic and telecommunication devices. It is however, rather challenging to combat the sacrificed magnetic loss due to magnetic dilution by the introduction of the dielectric component. Here a novel confinement strategy has been adopted to develop porous heterogeneous Fe7Co3/ZnO nanosheets where Fe7Co3 nanoparticles with single domain size and dispersed distribution can be achieved for enhanced natural resonance. The nanosheets exhibit unique porous feature with significantly reduced density. Also, tunable dielectric loss achieved via interruption of the Fe7Co3 conductive network functions synergistically with the magnetic loss for enhanced absorption over a wide frequency range (7.92 GHz), covering the complete Ku band and half of the X band. The confinement strategy proposed in this study not only paves the way for designing high-performance EM wave absorber with low density and broad bandwidth, but also provides a versatile method for the synthesis of two-dimensional composites with tunable composition for extended applications in energy storage, catalysis, biomedicine and sensing.

Food waste is a kind of wet bio-waste which has been a challenge for the ecological environment and disposal. In this paper, hydrogen production from subcritical water gasification (SbWG) of food waste with and without catalyst loading was systematically investigated. The effects of reaction temperature (300–360 °C), residence time (30–90 min), food waste concentration (10–30 wt%) and catalysts (Ni/γ-Al2O3, Ni/ZrO2, NaOH, KOH, and FeCl3) were studied within a pressure range of 10.5–20 MPa. The optimal process condition for SbWG of food waste without catalysts loading was determined to be 360 °C and 90 min with 10 wt% food waste. The liquid products and hydrochar were characterized by TOC, TGA/DTG, and SEM. The TOC concentration of liquid products decreased vastly with increasing reaction temperature. The highest H2 yield (1.88 mol/kg), H2 mole fraction (35.01%), and H2 selectivity (53.86%) were achieved at 360 °C for 90 min with 5 wt% loading of KOH. It can be concluded that the performance of the catalysts for improving hydrogen production in SbWG of food waste was in the following order: KOH > NaOH > Ni/γ-Al2O3 > Ni/ZrO2 > FeCl3. The catalytic SbWG can be a potential alternative for energy conversion of food waste and hydrogen production.

Surface nitridation has been used to fabricate the insulation coatings of the Fe, FeSi, FeSiAl and FeSiCr soft magnetic composites (SMCs). Effects of the nitridation conditions on the magnetic performance of the SMCs have been investigated. Detailed growth mechanism and models of the coating layers for different alloy systems have been established based on combined thermodynamic and kinetics analysis. For Fe and FeSi SMCs, nitride coatings containing α-Fe(N) forms, while coexistenc of α-Fe(N) and Fe4N is obtained for the FeSiAl SMCs. For the FeSiCr system, the nitride coating is composed of α-Fe(N) and CrN with relatively large electrical resistivity, giving rise to enhanced magnetic performance compared with that of the SMCs prepared via traditional phosphoric acid passivation.

This paper presents the results from experimental study of syngas production by catalytic cracking of tar in wastewater under supercritical condition. Ni/Al2O3 catalysts were prepared via the ultrasonic assisted incipient wetness impregnation on activated alumina, and calcined at 600 °C for 4 h. All catalysts showed mesoporous structure with specific surface area in a range of 146.6–215.3 m2/g. The effect of Ni loading (5–30 wt%), reaction temperature (400–500 °C), and tar concentration (0.5–7 wt%) were systematically investigated. The overall reaction efficiency and the gas yields, especially for H2, were significantly enhanced with an addition of Ni/Al2O3 catalysts. With 20%Ni/Al2O3, the H2 yield increased by 146% compared to the non-catalytic experiment. It is noteworthy that the reaction at 450 °C with the addition of 20%Ni/Al2O3 had a comparable efficiency to the reaction without catalyst at 500 °C. The maximum H2 yield of 46.8 mol/kgtar was achieved with 20%Ni/Al2O3 at 500 °C and 0.5 wt% tar concentration. The catalytic performance of the catalysts gradually decreased as the reuse cycle increased, and could be recovered to 88% of the fresh catalyst after regeneration. 20%Ni/Al2O3 has a potential to improve H2 production, as well as a good reusability. Thus, it is considered a promising catalyst for energy conversion of tar in wastewater.

A 3D large-sized nanocrystalline (NC) copper bulk was prepared by inert gas condensation and in situ warm compress, the density of which was 99.51% of theoretical value. Electrochemical methods and...

The rapid advancement of modern electronic technology requires MnZn ferrites capable of handling high-frequency signals, offering very low power loss and reasonably high permeability. MnZn ferrites were developed by using the conventional ceramic processing technique and the effects of Co2O3 and SnO2 doping on high-frequency magnetic properties were investigated. Co2O3 and SnO2 co-doping resulted in a sharp decrease of eddy-current loss and residual loss of the MnZn ferrites at 3–5 MHz and improved the temperature characteristics at 20–120 °C. The minimum power losses at 20 °C, 10 mT for 3 MHz and 5 MHz were 20 kW/m3 and 81 kW/m3, while the power losses at 100 °C, 10 mT for 3 MHz and 5 MHz were 60 kW/m3 and 205 kW/m3 respectively. The optimal saturation magnetic flux density and initial permeability were 480 mT and 675 respectively. The cut-off frequency of the sample was 12 MHz, establishing it as an ideal material for high-frequency applications.

Metacomposite absorbers could be optimized either by the magnetic and dielectric properties of absorbents or by periodically arranged structural units at macroscopic scale. Herein, high-performance microwave absorption Ni@C nanocapsules synthesized by a modified arc-discharge method were mixed with polyvinyl acetate adhesive and then formed a periodic millimetric pattern on a polyethylene terephthalate substrate. Such a metacomposite structure results in a significant tunability and enhancement for the microwave absorption, associated with the maximum absorption of structured absorbers presenting 52.34% absorption efficiency higher than 29.20% of the non-structured absorber. In particular, it is demonstrated that the anisotropic absorption resonances can be tuned by changing the rotation angle of multi-layered assembly. This enhanced absorption is well explained by theoretical simulation, owning to the millimeter “capacitor-like” dielectric couplings between the microstructural units. The present study thus shows an alternative way to design tunable metacomposite absorbers.

Magnetostriction deterioration has been observed in slowly cooled Fe-Ga alloys when compared with the high temperature quenched ones. To reveal the underlying origin, here we investigated the microstructure of Fe81Ga19 thin-sheet samples quenched after slow cooling (at ∼0.3 K/min) to near and below the decomposition phase boundary between A2 and (A2’ + L12) phases. In comparison with the sample quenched at 1273 K (much higher than the decomposition phase boundary, ∼793 K) or the one quenched near the decomposition boundary (773 K), magnetostriction deterioration is observed for the one quenched below the decomposition boundary (673 K). Besides the A2 matrix phase, quenching at 673 K also promotes the formation of secondary L12 phase with negative magnetostriction and the phase transformation induced dislocations located close to the grain boundaries. Simultaneously, weak D03 ordering of the untransformed bcc matrix is also observed. All these microstructural changes deteriorate the magnetostriction. Our work provides important information why the magnetostriction of Fe81Ga19 greatly depends on the thermal history.

Two-step post-sinter annealing (PSA) treatment, due to its universal applicability, has been one of the most effective strategies for enhancing the coercivity of Nd-Fe-B sintered magnets. Here we report a peculiar phenomenon that the as-sintered multi-main-phase (MMP) Nd-La-Ce-Fe-B magnet exhibits the highest reported to date coercivity of 13.0 kOe upon 25 wt% La-Ce substituting for Nd, combined with Br = 13.12 kG, and (BH)max = 41.67 MGOe. Further annealing cannot enhance the coercivity whereas the remanence and energy product are drastically lowered, i.e. to 11.0 kOe, 12.57 kG, and 38.71 MGOe after two-step PSA, being remarkably different from the conventional Nd-Fe-B. Microstructural analysis reveals that the as-sintered Nd-La-Ce-Fe-B magnet with coexisting REFe2 (Fd 3 ¯ m) and RE-rich (Fm 3 ¯ m) intergranular phases possesses continuous GB layer isolating adjacent ferromagnetic grains. Hence the beneficial role of PSA on modifying the microstructure and strengthening the coercivity is tiny. Additionally, high-temperature PSA destroys the initial chemical heterogeneity of MMP magnets, leading to the formation of REs homogeneously distributed grains and resultant reduction of the intrinsic magnetic properties. As evidenced by in-situ Lorentz TEM characterization, PSA sample with reduced chemical gradient exhibits quick domain wall motion, compared to the as-sintered one with basically unchanged magnetic domain structure upon the same applied field. The proof-of-principle micromagnetic simulation further confirms that retaining the inhomogeneous La/Ce/Nd distribution is essential to suppress the magnetic dilution effect. These findings demonstrate the realistic prospect of skipping PSA treatment in MMP magnets, which can not only reduce the production process and cost, but also delight the scenario for designing high-performance 2:14:1-type sintered magnets based on abundant La/Ce.

Developing high-capacity electrode materials is most vital to high-energy rechargeable batteries. The conversion reaction-based anode materials deliver substantially higher theoretical capacities in respect to intercalation-based materials. However, the sluggish conversion reaction kinetics is a big obstacle to deliver high practical capacity and rate capability, which is particularly severe for sodium storage. Herein, we implement an interface engineering approach by designing hetero-interfaces to enhance conversion reaction. As a proof of concept, Sb2S3-SnS2 hetero-nanostructures are synthesized and show greatly improved electrochemical performance in terms of specific capacity and rate capability. The DFT calculations reveal that the hetero-interfacial electric field prompts sodium ions pump into the interfaces, which greatly reduces the activation barrier and hence accelerates reaction kinetics. The Sb2S3-SnS2 hetero-interface serves therefore as a “reservoir” and fast diffusion channel for sodium or lithium ions. The obtained results provide important insights into engineering efficient hetero-nanostructures towards fast conversion reaction kinetics for rechargeable batteries.

Empty fruit bunch (EFB) is abundantly available for renewable energy resource, especially in Southeast Asian countries. However, EFB has inherent problems such as high moisture content, low heating value, and high alkali metal content. In order to improve the quality of feedstock as a fuel, in this research, the effects of hydrothermal treatment (HT) on the hydrothermally treated EFB (HT-EFB) characteristics were investigated. Also, the pyrolysis characteristics of EFB and HT-EFB were examined. The experiments of hydrothermal treatment were carried out in a 500-mL hydrothermal reactor at the temperature range of 120 to 220 °C with 60 to 120 min holding time. Afterward, the pyrolysis experiments of EFB and hydrothermally treated EFB (HT-EFB) were conducted in a lab-scale isothermal tube furnace at 400 °C for 1 h. The gas product was periodically collected to create gas evolution profiles. The result showed that hydrothermal treatment improved the properties of EFB, such as higher fixed carbon, lower ash content, and higher energy density. Hydrothermal treatment caused an increase in the heating value of HT-EFB to 19.47 MJ/kg, while the ratio of volatile matter/(volatile matter + fixed carbon) decreased from 0.82 to 0.68. Employing hydrothermal treatment in EFB did not only reduce the ash content of the biomass but also reduced the contents of potassium and sodium. In addition, the gas product from HT-EFB pyrolysis resulted in higher content of CO, CH4, and H2. The identified liquid product of pyrolysis consisted of alkane groups, phenolic groups, aromatic groups, ketones, acids, alcohols, and ester, which may be used as liquid fuel or for chemical production after further treatment. The observation indicated that hydrothermal treatment is an appropriate method to improve the fuel characteristic of EFB.

In this study, the model food waste was gasified to hydrogen-rich syngas in a batch reactor under supercritical water condition. The model food consisted of rice, chicken, cabbage, and cooking oil. The effects of the main operating parameters including temperature (420–500 °C), residence time (20–60 min) and feedstock concentration (2–10 wt%) were investigated. Under the optimal condition at 500 °C, 2 wt% feedstock and 60 min residence time, the highest H2 yield of 13.34 mol/kg and total gas yield of 28.27 mol/kg were obtained from non-catalytic experiments. In addition, four commercial catalysts namely FeCl3, K2CO3, activated carbon, and KOH were employed to investigate the catalytic effect of additives at the optimal condition. The results showed that the highest hydrogen yield of 20.37 mol/kg with H2 selectivity of 113.19%, and the total gas yield of 38.36 mol/kg were achieved with 5 wt% KOH addition Moreover, the low heating value of gas products from catalytic experiments with KOH increased by 32.21% compared to the non-catalytic experiment. The catalytic performance of the catalysts can be ranked in descending order as KOH > activated carbon > FeCl3 > K2CO3. The supercritical water gasification (SCWG) with KOH addition can be a potential applied technology for food waste treatment with production of hydrogen-rich gases.

Y-Ce co-substituted RE-Fe-B (RE, rare earth) sintered magnets with good thermal stability have attracted growing attention as low-cost hard magnetic materials. The inferior intrinsic properties of Y2Fe14B and Ce2Fe14B to Nd2Fe14B, however, limit the substitution of Y-Ce for Nd at a low level. In this work, (Nd, Pr)-Hx powders are introduced into (Nd, Pr)22.8(Y, Ce)7.7FebalM1.3B1.0 sintered magnets to further enhance the coercivity. By incorporating 1 wt% (Nd, Pr)-Hx, the coercivity is increased to 9.7 kOe, which is 16.9% higher than that for the starting magnet (8.3 kOe). Continually increasing (Nd, Pr)-Hx addition to 2 and 3 wt% lead to a very limited coercivity increment, i.e. to 10.0 kOe and 10.3 kOe, respectively. The formation of continuous RE-rich intergranular phase by the extra Nd/Pr after (Nd, Pr)-Hx dehydrogenation can enhance the magnetic isolation effect between adjacent matrix phase grains, resulting in coercivity enhancement. However, more Nd atoms exist in the RE-rich phase rather than form the Nd-rich hardening shell, which is distinct from the available Nd-Ce-Fe-B system. The REs distribution within the matrix phase grain is similar before and after (Nd, Pr)-Hx incorporation for the Nd-Ce-Y-Fe-B system. It is deemed that the preferential occupancy of Y in the 2:14:1 matrix phase hinders the diffusion of Nd into the outer layer of Y-Ce enriched regions, being responsible for the limited coercivity increment with higher (Nd, Pr)-Hx addition. The present work suggests that tuning the distribution of Y is of crucial importance to further improve the coercivity of Y-containing permanent magnets.

Developing lightweight and thin electromagnetic (EM) wave absorbers with a broad bandwidth remains a major challenge for reducing EM pollution originating from the rapidly increasing amount of electronics. Herein, porous Co9S8 nanotubes synthesized through a facile self-template method are applied as a single-component EM wave absorber. Based on percolation theory, an appropriate balance between excellent impedance matching and strong loss ability can be achieved for the Co9S8/paraffin composite with 30 wt% filler loading, giving rise to a broad effective absorption bandwidth almost covering the entire Ku band, or X band with varied Co9S8 loadings. This study provides a new concept for the design of single-component EM wave absorbing materials with even superior performance to those of many multicomponent absorbers.

To assess the application value of the seeds of the traditional medicine Chishao (Radix Paeonia Rubra, the root of Paeonia veitchii Lynch), the thousand seed weight, oil and kernel contents of the seeds, composition and contents of the main fatty acids, the physical and chemical characteristics of the seeds oil, and proximate composition and phytochemical components of the seeds shell and seeds oil residue were evaluated in this study. In addition, bioactivities such as antitumour and antimicrobial activity of the oligostilbene compound from P. veitchii seeds shell, and the inhibitory activities of the monoterpene glycoside compounds in P. veitchii seeds oil residue were also evaluated using different in vitro biochemical assays. The results showed that the seeds of P. veitchii had high oil content, and the seeds oil was characterized by very high levels of unsaturated fatty acids. The seeds shell contained large amounts of cellulose, lignin, and oligostilbene compounds, and high levels of monoterpene glycosides and crude protein were found in the P. veitchii seeds oil residue. The results of the biological tests showed that total oligostilbene compounds from P. veitchii seeds shell had antibacterial activity and moderate anticancer effects in vitro, and the total monoterpene glycoside compounds in P. veitchii showed strong inhibitory activities against NO production. As a medical plant and industrial crop with broad prospects, P. veitchii can be planted in most regions of China. In the past, it was planted solely because of the medical use of the roots. The above proximate and phytochemical profile, and bioactivity results show that the seeds of P. veitchii have high utilization value with potential in the development of value-added products, representing another valuable part of P. veitchii in the near future.

Influences of (Nd, Pr)H x additives on the microstructure and mechanical properties of Nd–Pr–Ce–Fe–B sintered magnets have been investigated. The results show that both the fracture toughness and bending strength exhibit a monotonically increasing trend with raised (Nd, Pr)H x incorporation. The (Nd, Pr)H x powders transform into metallic Nd/Pr with high reactivity upon dehydrogenation, increasing the volume fraction of rare earth-rich intergranular phase, and promoting the formation of thick and continuous grain boundary (GB) layer surrounding the RE2Fe14B matrix phase grains. Besides, the hydrogen desorption behavior also demonstrates that the excessive hydrogen introduced by (Nd, Pr)H x additives can be completely released upon high-temperature sintering. As a result, the crack propagation along the thick GBs is suppressed, giving rise to the substantially enhanced mechanical performance of bulk magnets. This paper suggests that the Nd–Pr–Ce–Fe–B permanent magnet with (Nd, Pr)H x incorporation satisfies the constraints of cost, magnetic, and mechanical properties simultaneously, thereby possessing competitive advantages for mass production.

Single-phase cobalt ferrite nanoparticles were synthesized by coprecipitation method and annealed at different temperatures. The structural, dielectric and magnetic properties were investigated, which showed an obvious dependence on annealing temperature. The average crystallite size increased from 20 to 60 nm with increase of annealing temperature. Meanwhile, the shape of nanoparticles also changed from spherical to octahedron and then cubic. Dielectric constant showed dispersion behavior and decreased with increasing annealing temperature, while the relaxation peaks observed in dielectric loss were shifted to lower frequencies. The ac conductivity originates from Polaron hopping which decreased with increase of crystallite size (less surface area and defect density) due to higher annealing temperature. The saturation magnetization increased from 59 to 81 emu/g and coercivity dropped from 1316 to 428 Oe with the increase of particle size.