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Bi-doped La1.5-xBixSr0.5Ni0.5Mn0.5O4+δ (LBSNM-x, x = 0, 0.05, 0.1, 0.15) was investigated as a potential air electrode for solid oxide electrolysis cell (SOEC). The effect of Bi doping on the structure, electrical conductivity, chemical compatibility with GDC electrolyte, electrochemical performance and thermal expansion coefficients (TECs) were investigated. XRD characterization results show that the solid solution content of Bi is less than or equal to 0.1. XPS characterization results indicate that Bi doping increases the oxygen vacancy content of LBSNM-x air electrode and thus greatly benefits its oxygen evolution reaction. Among the Bi-doped samples, LBSNM-0.1 electrode has the best electrochemical performance with its lowest Rp (polarization resistance) of 0.28 Ω cm2 at 800 °C based on LBSNM-0.1/GDC half-cell. LBSNM-0.1 single cell with 70%CO2 + 30%CO fuel gas feed on the fuel electrode has achieved current density of 811 mA cm−2 at 800 °C and 1.4 V, a 62.2% increase relative to that of LSNM single cell. In addition, LBSNM-0.1 single cell exhibits excellent stability at 800 °C and 1.3 V with 70%CO2 + 30%CO feed gas on the fuel electrode. These results prove that Bi-doped LBSNM-0.1 is an efficient air electrode for SOEC.

Electrolysis of CO2 into CO by using solid oxide electrolysis cells (SOECs) is an advanced and sustainable energy conversion technology in the production of chemical energy by electrical power. However, the development of SOECs is limited because of the lack of cathode with high activity and stability. Herein, La0.75Sr0.25-xCaxCr0.5Mn0.5O3/Gd0.1Ce0.9O2-δ (Cax-LSCM/GDC, x = 0, 0.05, 0.1 and 0.15) composites were obtained by introducing Ca into the A-site of LSCM and developed as desirable cathodes for high-temperature electrolysis of CO2. The electrode polarization resistance (Rp) for CO2 electrochemistry reduction of the half-cell with the Ca0.05-LSCM/GDC cathode shows the minimal values within different temperature and voltage ranges, this cathode has a Rp value of 0.98 Ω cm2 at 800 °C under an applied voltage of 1.0 V, which is decreased by 32% compared with that of the LSCM/GDC cathode under the same test condition. The current density of the full cell with the configuration of Ca0.05-LSCM/GDC|ScSZ|LSM/GDC achieves 31% increase at 1.2 V and 800 °C compared with that of LSCM/GDC cell. Moreover, Ca0.05-LSCM full cell remains fairly stable after 100 h of continuous operation in pure CO2 atmosphere. Results indicate that Ca doped LSCM may be a reliable cathode material for CO2 electrolysis in SOECs.

Carbonaceous materials present the promising anode candidates for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs), however, the poor rate performance and low capacity due to limited interlayer spacing greatly impact their practical application. Herein, we report soybean roots-derived mesoporous hard carbon constructed by N, P co-doping (NPDCs) with enlarged interlayer distance and more active sites for high-performance SIBs and PIBs. As a result, the optimized NPDC achieves an excellent cyclic stability (197 mA g−1 after 2000 cycles at 2.0 A g−1) for SIBs, superior rate capability (a high reversible capacity of 179 mAh g−1 at 5.0 A g−1) for PIBs. Kinetic and first-principles calculation studies further demonstrate the dual-doping improves the Na (K) ions diffusion and adsorption as well as electrons transport. This work provides a facile and sustainable strategy to realize advanced carbon-based materials with heteratoms doping in application for energy storage devices.

Due to the sodium abundance and availability, sodium-ion batteries (SIBs) have the potential to meet the worldwide growing demand of electrical energy storage. P2-type sodium transition-metal layer oxides with a high energy density are considered as the most promising cathode materials for SIBs. We present here a detailed study of the enhanced rate capability and cyclic stability of the Ti-doped Na0.67Ni0.33Mn0.67O2 cathode material. The combined analysis of ex-situ X-ray absorption fine structure (XAFS) spectroscopy, aberration-corrected high resolution transmission electron microscopy (AB-HRTEM) and X-ray diffraction (XRD) show that the strong Ti–O bond in the transition metal layers stabilizes the local structure, destroy the Na+-vacancy ordering and arrest the irreversible multiphase transformation that occurs during the intercalation/deintercalation process. Actually, Na0.67Ni0.33Mn0.52Ti0.15O2 exhibits a reversible capacity of 89.6 mA h g−1 even at 5 C, an excellent cyclability with 88.78 % capacity retention after 200 cycles at 0.5 C. This study provides a better understanding in optimization of the design of high-energy cathode materials based on titanium doped layered oxides for SIBs.

The SnSe nanoparticles encapsulated in the carbon nanofibers (SnSe@C) with microrod morphology and core–shell structure are prepared by electrospinning and annealing process, and investigated as anode materials for sodium ion batteries. Benefiting from this unique structure, the SnSe@C can deliver a reversible capacity of 283.8 mAh g−1 after 500 cycles at a high current density of 1.0 A g−1. The sodium ion storage mechanisms of SnSe are further characterized by ex-situ X-ray diffraction, high-resolution transmission electron microscope and selected area electron diffraction measurements. Besides, the excellent electrochemical performance of the electrodes is investigated by pseudocapacitance and in situ electrochemical impedance spectroscopy measurements. This work may provide a new avenue for synthesis of metal selenides with core–shell structure and a good idea for studying the kinetics process.

Compounds with chain structures have received great attention due to their unique quasi-one-dimensional charge transport channel which usually leads to striking physical phenomena. Here, we report the synthesis and detailed physical properties of Ba7Fe6S14 single crystals whose crystalline structure is featured by one-dimensional chains constituted by units of FeS4 tetrahedra. Susceptibility measurements reveal three magnetic phase transitions located at T = 10.5 K, 38 K, and 121 K. Further heat capacity measurements suggest a second-order phase transition for the transition at 121 K. At ambient pressure, the compound is an insulator with a large thermal activation energy around 0.19 eV. Application of pressure can gradually suppress the insulating behavior, and pressure-induced insulator-metal transitions can be achieved for P ≥ 21.3 GPa. No superconductivity was observed with pressure up to 47 GPa. Nevertheless, the unique chain-like structure of Ba7Fe6S14 provides chances for comparative studies with the quasi-one-dimensional spin-ladder iron-based superconductor BaFe2S3 for exploring the relation among crystalline dimensionality, magnetism, and superconductivity.

This brief presents a low voltage folded-switching ultra-wideband down-conversion mixer in TSMC 0.18 $\mu \text{m}$ SiGe BiCMOS technology. The transconductance stage uses BJT (HBT) transistors to improve the conversion gain. The switching stage uses a CMOS inverter that is switched to reduce the supply voltage and the dc power consumption. The design technology for the mixer combines the advantages of BJT (HBT) and CMOS. The results show a conversion gain of 8.8~ 17.1 dB, ranging from 3 GHz to 11 GHz, a single-ended noise figure from 12.8 dB to 16.56 dB, an input return loss of less than −8 dB and LO-to-RF isolation that is better than −32 dB. The IIP3 is 0 dBm at 3 GHz. The total dc power consumption from a 1V supply voltage with output buffers is 3.45 mW.

The low efficiency and instability of electron emission from two-dimensional (2D) materials such as WS2 and NiS hamper application to vacuum microelectronic devices. Although nickel-based alloys have many favorable physicochemical properties suitable for nanoelectronics, electron field emission (FE) from heterostructures comprising tungsten-nickel sulfide alloys and graphite carbon (WNi–S/C) has been seldom studied because it is difficult to fabricate the nanostructures in situ. In this work, field emitters composed of the WNi–S/C nanobelt composite are produced on Si microchannel plates (WNi–S/C@Si) hydrothermally. The structure has a porous and vertically aligned 3D morphology in addition to excellent adhesion strength with the substrate. Geometrical modulation of the WNi–S/C@Si is performed by changing the hydrothermal reaction temperature and an ultralow turn-on electric field of 0.51 V μm−1 for a current density 0.1 mA cm−2, threshold electric field of 0.65 V μm−1 for a current density of 1 mA cm−2, and stability of 97.1% for 8 h are accomplished. The related mechanisms are investigated and discussed. Moreover, finite element simulation shows that not only the shape of the nanostructures but also the high aspect plays a key role in reducing screen effects. These outstanding properties suggest large potential in high-performance FE and vacuum nanodevices.

Poor electrical conductivity and large volume changes are two disadvantages of metal selenides. In this work, MnSe nanoparticles encapsulated into N-carbon fibers are designed and prepared using electrospinning and calcination methods. When calcined at 700 °C, the composite has a high reversible capacity of 684 mAh g−1 after 100 cycles at 0.1 A g−1, owing to the improved conductivity and protection provided by carbon fibers. Furthermore, the in situ electrochemical impedance measurements reveal the process kinetics of the composites. This work will provide the basis for the further development of the application of metal selenides in the field of flexible electrodes.

A novel Fe2O3–Fe3C heterostructure encapsulated into a carbon matrix was designed as an anode material for lithium-ion batteries. The composite had the high specific capacity of metal oxides, and maintained the stability of metal carbides. The unique heterostructure and tubular structure were conducive to charge transfer and ion diffusion.

Solid oxide electrolysis cell (SOEC) is a promising electrochemical device with high efficiency for energy conversion and storage. In this work, La1.5Sr0.5Ni1-xMnxO4+δ (LSNMx) (x = 0, 0.1, 0.25, 0.5, 0.75) Ruddlesden-Popper oxides are synthesized via the conventional solid-state method and evaluated as potential air electrodes for SOEC. The effects of substituting Mn for Ni on the crystal structure, oxygen content, thermal expansion behavior, electrical conductivity, and electrochemical performance are comprehensively investigated. XRD results show that the solid-solution concentration of Mn in LSNMx cannot exceed 0.5. The X-ray photoelectron spectroscopy of O1s suggest that Mn doping increases the concentration of oxygen vacancy. The polarization resistance (Rp) of LSNMx (x = 0, 0.1, 0.25, 0.5) exhibits a significantly decreasing tendency with increasing Mn content. LSNM0.5 shows the lowest Rp value of 0.488 Ω cm2 at 800 °C and is reduced by as much as 81.1% in comparison with that of the LSN electrode. A current density of 500 mA cm−2 at 1.4 V is obtained for the LSNM0.5 air electrode with 70% CO2 + 30% CO feed gas on the fuel electrode in a fuel electrode-supported single cell at 800 °C. This current density shows an increase of approximately 85.2% compared with that of the un-doped LSN electrode. The stability test of the half-cell shows that the LSNM0.5 air electrode is relatively stable after anodic polarization at 500 mA cm−2 and 800 °C in air for 145 h. Thus, the Mn-doped LSNM0.5 Ruddlesden-Popper material is a promising air electrode for SOEC.

Sb‐based oxides electrodes have received tremendous attention owing to their high theoretical capacities and electrochemical activities. However, the huge volume change during ion insertion/extraction process and poor electronic conductivity limit their wide applications in the electrochemical energy storage. In this study, SbO2/Sb2O3 nanoparticles embedded in N‐doped carbon fibers are successfully synthesized. The composite can display a high reversible specific capacity of 622 mAh g−1 for lithium‐ion batteries and a desirable reversible capacity 307 mAh g−1 for sodium‐ion batteries at current density of 100 mA g−1. Such superior lithium and sodium storage performance can be ascribed to that carbon fibers can effectively restrict the large volume change and enhance the electrochemical stability.

This study presents an ultra-wideband up-conversion mixer chip that operates within the frequency range of 2–12 GHz using TSMC 0.18 μm complementary metal oxide semiconductor (CMOS) technology. The architecture is based on that of a Gilbert cell mixer. The design of the transconductance stage is based on an inverting amplifier. Two series resonant inductors are used to increase the conversion gain of the mixer, and a transformer that consists of two self-made inductors reduces the spatial requirement of the chip. This up-mixer achieves a 12.48 dB conversion gain and features an excellent gain flatness value of ±1.2 dB. The local oscillator (LO)-to-radio-frequency isolation is 44–20 dB, the input third-order intercept point (IIP3) is −6.8 to −8 dBm and the DC power consumption is 5.084 mW for a supply voltage of 1 V. The total size of the chip for the up-mixer is 1.2 × 1.2 mm2, including the pad frames.

The work aim to the reaction mechanism of laser engraving polycarbonate (PC)-based films. The calculation of infrared-laser acting on the PC films, was carried out by using one-dimensional heat conduction model. The power density of laser device required for laser engraving polycarbonate-based films was determined to be 4.86~7.73×104 W/cm2. Characterized by the FTIR spectra, SEM, DSC and TGA, the reaction mechanism was studied. The results show that the light-sensitive particles in the PC films absorb the laser energy with wavelength of 1064nm. After reaching the temperature of 509°C, the main chain of PC molecule opened due to the breakage of C-O bond in PC molecular terminal group and C-O bond between PC monomers. As the energy continues to be absorbed, the temperature reach to 610°C, the decomposition products decomposed into carbon black, which can form a black carbon spot.

Cobalt carbonate hydroxide possesses interesting capacitive properties due to the unique crystal structure. Herein, the hierarchical Co3O4@Co2(CO3)(OH)2 dendritic structure was fabricated on carbon cloth with Co3O4 nanoneedles as the inner core to enhance the conductivity. The loading efficiency of Co2(CO3)(OH)2 nanowhiskers had improved obviously, and the nanowires provided more electrochemical sites to facilitate the superior electrochemical energy storage capacity of supercapacitor. The dendritic electrode with the core–shell structure had a high area-specific capacitance (1541 mF cm−2 at 1 mA cm−2), good rate capacitance (only 18.1% specific capacitance lost when the current density increased to 5 mA cm−2), as well as better electrochemical cycle stability (a capacitance retention of 72.1% after 5000 cycles at a high current density of 5 mA cm−2). The dendritic Co3O4@Co2(CO3)(OH)2 and activated carbon as cathode and anode, respectively, were used to assemble an asymmetric supercapacitor, possessing the better area-specific capacitance of 87 mF cm−2 as well as well-deserved longevity retaining approximately 97.3% of initial capacitance even after 10,000 cycles at 1 mA cm−2. The excellent properties stemmed from electro-active sites galore, strong adhesion between the core and shell, superior conductivity, as well as excellent ion transfer. The novel materials and feasible strategy are promising for next-generation hybrid supercapacitor with high performance.

Transition metal phosphides (TMPs)/carbonaceous matrices have gradually attracted attention in the field of energy storage. In this study, we presented nickel phosphide (Ni2P) nanoparticles anchored to nitrogen-doped carbon porous spheres (Ni2P/NC) by using metal-organic framework-Ni as the template. The comprehensive encapsulation architecture provides closer contact among the Ni2P nanoparticles and greatly improves the structural integrity as well as the electronic conductivity, resulting in excellent lithium storage performance. The reversible specific capacity of 286.4 mA h g−1 has been obtained even at a high current density of 3.0 A g−1 and 450.4 mA h g−1 is obtained after 800 cycles at 0.5 A g−1. Furthermore, full batteries based on LiNi1/3Co1/3Mn1/3O2||Ni2P/NC exhibit both good rate capability and cycling life. This study provides a powerful and in-depth insight on new advanced electrodes in high-performance energy storage devices.

Earth-abundant transition-metal selenides (TMSs) have aroused great interest towards their application in sodium-ion batteries (SIBs). Herein, we present Fe-based Prussian blue analogs (PBA) modified by graphene oxide as precursors to synthesize FeSe2 nanoparticles within a nitrogen-doped carbon (NC) matrix and graphene layer (FeSe2/NC@G). The bifunctional carbon wrapped FeSe2/NC@G shows excellent sodium-storage performance with a large reversible capacity of 331 mA h g-1 at 5.0 A g-1 and a high cyclability of 323 mA h g-1 at the current density of 2.0 A g-1 after 1000 cycles (82% capacity retention). Furthermore, full SIBs are also fabricated and exhibit superior capacities and stabilities. The remarkable electrochemical properties result from the formation of an Fe-O-C chemical bond in the composite with enhanced electronic/ionic diffusion kinetics and structural integrity. This study paves the way for the successful synthesis of novel nanostructural TMSs which can be utilized in energy storage system application.

We rationally design a hybrid composite with ultrasmall CoSe2 nanoparticles encapsulated by N-doped carbon matrix. The excellent electrochemical performance of composite can be owing to the synergistic effect of N-doped carbon matrix and ultrasmall CoSe2 nanoparticles.

In recent years, nanoporous alloys have presented the advantages of a large specific surface area, low density, and simple operation, and they have been widely used in the fields of catalysis, magnetism, and medicine. Nanoporous Pt-Si alloy was prepared by melt-spun and chemical dealloying, and was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope, and transmission electron microscopy. Pt-Si alloys possess a three-dimensional bicontinuous structure and an average size of 5 nanometers. Compared with commercial Pt/C catalysts, nanoporous Pt-Si alloys exhibit excellent electrocatalytic activity and stability in ethanol-catalyzed oxidation reactions. It is taken into consideration to be a promising catalyst in direct ethanol fuel cells.

Spacecraft play an important role in the national economy and other fields. Solar cell array is the most critical power supply component on spacecraft, and its joining quality determines the success and failure of flight missions. The joints operate in high and low temperature alternating environment when the spacecraft is in orbit. Therefore, the thermal reliability of joints is an important factor to a life of spacecraft. In this paper, the joints between GaAs solar cell electrode and Ag interconnector have been joined using a parallel gap resistance welding (PGRW) process. The joints are conducted a thermal cycling test in a temperature range of -160 to 120°C. The heating and cooling rate are 15 °C/min and maintains 10 min at -160°C and 120°C, respectively. The joints are taken out after different thermal cycle number and pull test are performed. To characterize the microstructure evolution and failure mode at the interface before and after thermal cycle, scanning electron microscope (SEM), transmission electron microscopy (TEM) are conducted to investigate the joining interface. According to the obtained results, the PGRW interface between the Ag interconnector and the Au surface of the GaAs solar cell electrode forms a solid-solution layer in low voltage process. The joining mechanism is solid phase diffusion welding. Melting connection occurs in the central region of two electrodes in high voltage process. The performance of joints with a lower welding voltage shows a downward trend after thermal cycles. And failure occurs at interface after 5000 cycles. The performance of joints with a high welding voltage still keeps invariability. This is owing to the boding zone increases and the joining mechanism varies. The fracture surface also varies form characteristics of dimples to characteristics of cleavage fracture with a low voltage process after 5000 cycles.

Optical emission of plasma induced by a pulsed laser ablating the surface of a randomly packed granular (RPG) material in air is investigated experimentally, taking sieved copper microspheres with discrete diameters, d, ranging from 49 to 390 \textmu{}m as examples. We find a steplike phenomenon (also called a critical-like phenomenon) in the dependence of plasma emission on the grain size: when d is less than a critical size, only weak emissions are detected; however, when d exceeds the critical size, the emissions abruptly become at least 5 times stronger. Such a phenomenon can be explained by considering the RPG material as a non-Newtonian fluid with a yield stress and an effective viscosity. Specifically, in the range of the grain size above (below) the critical value, the RPG target has a yield stress larger (smaller) than the shock pressure imparted by the energetic processes of plasma generation and expansion, and thus, behaves like an elastic solid (a viscous fluid) to assist (impede) the formation of the plasma with high temperature and high density as an optical emission source for spectrochemical analysis. This work not only has significance in assessing a lower size limit for direct multielement analysis of RPG material using laser-induced breakdown spectroscopy (LIBS), but also shows that the mechanical characteristics of RPG material may be probed using LIBS.

A facile method is designed to synthesize CeO2 nanoparticles embedded one dimensional N doped carbon matrix by the electrospinning and calcination process. The electrochemical tests reveal that the CeO2@NC composite delivers excellent electrochemical performance with good cycling stability and rate capability. CeO2@NC composite exhibits a high reversible capacity of 724.8 mAh g−1 after 100 cycles at a current density of 100 mA g−1, owing to that the one dimensional N doped carbon matrix can effectively improve the electron conductivity of composite and accelerate the ion transfer with short diffusion length. This work can be extended to construct one dimensional other metal oxides/carbon composite and applied in a new generation of anode materials.

Transition metal phosphides (TMPs) have attracted much considerable interest for electrochemical energy storage, due to their high theoretical capacity and earth-abundant. In this work, we report ultrafine carbon-coated bimetal phosphide nanoparticles embedded into the nitrogen-doped graphene network (NGN) through a solution-phase self-assembly strategy. The unique carbon-coated Ni1.4Co0.6P nanoparticles and strongly coupled with NGN can not only provide more active sites for lithium-ions reaction and enhance the conductivity of electrode, but also restrain the volume expansion during the charge/discharge process. When evaluated as anode material for lithium-ion batteries, the as-prepared hybrid electrode exhibits high specific capacities (1320 mAh g−1 at 120 mA g−1), superior rate capability (227 mAh g−1 at a current density of 3000 mA g−1) and excellent cycling stability (350 mAh g−1 at 1200 mA g−1 after 1000 cycles). This work can be extended to develop advanced electrode materials for next-generation energy storage systems.

The large volume change and low electronic conductivity are the two main drawbacks for metal carbonates as promising anode materials of lithium-ion batteries. Metal doping is one of the most effective methods to address these issues. Herein, cadmium-doped ferrous carbonate Fe1–xCdxCO3 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) composites have been synthesized by a simple hydrothermal method for the first time. The morphologies of FeCO3 are evolved from microspheres to the agglomerated nanoparticles and then nanocubes with the increase of Cd doping. Fe0.8Cd0.2CO3 microspheres deliver higher capacity and cycling stability in Fe1–xCdxCO3 composites and better electrochemical performance than the corresponding 0.8FeCO3 + 0.2CdCO3 mixtures owing to an inner synergistic effect between Cd and Fe atoms in Fe1–xCdxCO3. The density functional theory calculation and electrochemical impedance spectroscopy results indicate that Fe0.8Cd0.2CO3 can maintain the similar electronic structure with good electric conductivity to FeCO...

Cobalt sulfides (including CoS, CoS2, Co3S4, Co9S8 and nonstoichiometric Co1−xS) are deemed to a kind of novel anode material for lithium ion batteries due to their large specific capacities. However, cobalt sulfides suffer from poor cycling stability with the large volume expansion. In this work, we designed and synthesized a novel Co-metal organic frameworks (MOFs) material by using carbazolyl carboxylates ligand H4DCDC. The Co1−xS nanoparticles embedded in N-doped carbon sheets (Co1−xS/NCS) composites are obtained via vulcanizing the Co-MOFs precursor. As a result, the Co1−xS/NCS exhibits outstanding cycling stability and maintains a high capacity of 796.3 mA h g−1 at the current density of 200 mA g−1 after 100 cycles. The N-doped carbon sheets can not only enhance the conductivity of materials but also buffer the volume expansion during charge-discharge process.

In this work, the effect of Ga substitution on the crystal structure, phase transitions, magnetocaloric effect, and exchange bias properties, was systematically investigated in Ni43Mn46Sn11−xGax alloys. With increasing Ga content, the Curie temperature of austenite slightly decreases, while the martensitic transformation temperature shifts to a higher temperature and finally disappears, due to the emergence of γ phase. Large low-field magnetic entropy changes around the martensitic transformation were observed as the transition from a paramagnetic martensitic phase to a ferromagnetic austenitic phase took place. Ni43Mn46Sn11 has a reentrant-spin-glass ground state, and Ga doping can enhance the antiferromagnetic interaction arising from lattice contraction, leading to close of intermediate ferromagnetic windows and establishment of canonical spin-glass for x > 2. Prominently, the zero-field-cooled exchange was achieved in the spin-glass region with 5 ⩽ x ⩽ 10 .

The crystal structure, phase transitions, and exchange bias (EB) in Al-doped Ni50Mn36Sn14-xAlx Heusler alloys were investigated. With the increase of Al content, the cell volume decreases gradually, and the martensitic transformation temperature shifts to a higher temperature. Due to the positive “chemical pressure” by Al substitution, the antiferromagnetic interaction strengthens, leading to the decrease of magnetization and the ground state evolution from “reentrant” spin glass to spin glass. Zero-field-cooled EB is triggered in samples exhibiting spin-glass ground state. These results suggest a viable way to design Ni-Mn-Z-based alloys showing zero-field-cooled EB by tuning the exchange interactions and ground state via lattice modulation.

The interesting phenomena induced by the interaction between local moments and itinerant electrons in 4f compounds have attracted extensive attention for many years. Here, we report the synthesis of a new 4f compound, i.e. NdPd1-δBi2 (δ∼0.23) which is superconducting with a transition temperature Tc around 3.2 K. A comprehensive investigation of the thermodynamic properties suggests NdPd1-δBi2 is also an anti-ferromagnet with the Neel temperature TN ∼4 K. Moreover, its high-temperature paramagnetic state is characterized by an enhanced heat capacity with a Sommerfeld coefficient γ over 300 mJ mol−1 K−2, which presumably results from Nd3+ crystal-electric-field splitting rather than the Kondo effect. In the superconducting state, the suppression of superconductivity with field increasing for H ||c is faster in comparison with H || ab, resulting in a moderate upper critical field anisotropy with Γ = H c 2 ( 0 K , ‖ a b ) / H c 2 ( 0 K , ‖ c ) ∼2.6. Collectively, NdPd1-δBi2 may serve as an intriguing system to study the interplay among magnetic order, Kondo effect, and superconductivity in 4f compounds.

High-performance transition metal carbonates are considered as promising electrode materials in lithium-ion batteries. However, the poor conductivity limits their further application. Herein, graphene modified CdCO3 cubic particles composite (CdCO3@rGO) are prepared using a facile hydrothermal method and their electrochemical performance are discussed. CdCO3@rGO can maintain a reversible capacity of 423.1 mAh g−1 at 200 mA g−1 after 100 cycles while CdCO3 only delivers a capacity of 142.0 mAh g−1. The excellent cycling stability and rate capability of CdCO3@rGO can be attributed to graphene modification, which not only decreases the particle size with large surface area but also improves the electronic conductivity and effectively buffers volume changes during the lithium insertion/extraction process.

Safety is a stumbling block to the applications of the lithium-ion batteries in electric vehicles, especially under the abuse condition of overcharge. Much research on preventing overcharge is bein...

Herein, ultrasmall MnO nanoparticles encapsulated by nitrogen-rich doped carbon matrix hybrids are synthesized by annealing ethylenediaminetetraacetic manganese [Mn2(EDTA)] precursors for the first time. The resulting MnO@NDC composite exhibits excellent rate capability and outstanding cycling stability as an advanced anode material for lithium-ion batteries.

Niobium oxide has been extensively investigated as a promising anode material owing to its special structure and excellent electrochemical performance. Herein, Multiwalled carbon nanotube (MWCNT)-modified Nb2O5 is prepared by using a simple hydrothermal method. The morphologies tests show a uniform particle size of Nb2O5 and the average distribution of MWCNTs between nanoparticles. The electronic and ion conductivity of Nb2O5 can be improved by the MWCNT modification. The fabricated Nb2O5-MWCNT composites deliver superior electrochemical performance than the pristine Nb2O5 and MWCNT. Ex situ tests reveal that the capacity of Nb2O5 is mainly provided by the Nb4+/Nb5+ electrochemical couple.

Measurement accuracy is an important performance indicator for high-voltage direct current (HVDC) voltage dividers. The temperature rise effect for a HVDC voltage divider’s internal resistance has an adverse effect on measurement accuracy. In this paper, by building a solid model of a DC voltage divider, the internal temperature rise characteristic and error caused by the temperature rise in a resistance voltage divider were theoretically simulated. We found that with the increase in height and working time, the internal temperature of the voltage divider increased. The results also showed that the lowest temperature was near the lower flange and the highest temperature was near the upper flange in the middle of the voltage divider. The error caused by the temperature rise increased first and then decreased gradually with divider height, increasing with its working time. The measurement error caused by the internal temperature difference in steady state reached a maximum of 158.4 ppm. This study provides a theoretical basis to determine the structure and accuracy improvement for a resistive voltage divider, which is helpful for the selection of components and the optimization of the heat dissipation structure.

Rare-earth monopnictides are predicted to be nontrivial semimetal candidates and show pressure-induced superconductivity. Here, we grow LuBi single crystal and study the magnetization, transport behaviors and electronic band structures to reveal its topological semimetal feature and superconductivity under pressure. At 0 GPa, the quantum oscillations indicate that there are several topologically nontrivial carrier pockets around the Fermi level, among which the hole ones are isotropic in shape, while the electron ones are anisotropic and responsible for the angular magnetoresistance. Upon compression, the superconductivity emerges in the titled compound, showing a similar pressure dependence as that observed in LaBi. Our calculation suggests that the electronic band structures are robust at low- and high-pressure respectively and thus the topological features are always preserved. Besides, the nearly pressure-independent density of state in LuBi indicates that the conventional electron-phonon coupling appears to play a minor role in the superconductivity.

In this paper, a bandwidth controllable filtering waveguide is proposed. The filtering waveguide consists of a common rectangular waveguide and metasurface-based metallic bars. Inside the operational frequency band, the metallic bars forming a metasurface can behave as perfect electric conductor (PEC), which generates a pass-band for signal transmission, while outside the band of interest, the metallic bars act as perfect magnetic conductor (PMC) and block the transmission of undesired signals, where a stop-band is generated. After integrating the pass-band and stop-band features into the waveguide, a customized waveguide with filtering response is realized. Moreover, the pass-band and stop-band of the filtering waveguide can be flexibly and easily adjusted to meet different requirements with low insertion loss.

In this paper, a metal-strip integrated filtering waveguide is proposed. The overall structure consists of a traditional rectangular waveguide and a metal-strip surface which is loaded at the bottom wall of the waveguide. The customized surface can be considered as a meta-surface, when the surface acts as a PEC, the filtering waveguide works at pass-band. When the surface plays a role as a PMC outside the interested frequency band, a stop-band can be created. The proposed filtering waveguide operates in Ku-band with pass-band of 12 GHz~15.1 GHz and stopband of 15.8 GHz~17.4 GHz. Simulation results show that the reflection coefficient of the waveguide in the passband is lower than -20 dB, and the propagation coefficient in the stopband is lower than -60 dB.

The lack of online sensors for Mooney viscosity measurement has posed significant challenges for enabling efficient monitoring, control, and optimization of industrial rubber mixing process. To obtain real-time and accurate estimations of Mooney viscosity, a novel soft sensor method, referred to as multimodal perturbation- (MP-) based ensemble just-in-time learning Gaussian process regression (MP-EJITGPR), is proposed by exploiting ensemble JIT learning. This method employs perturbations on similarity measure and input variables for generating the diversity of JIT learners. Furthermore, a set of accurate and diverse JIT learners are built through an evolutionary multiobjective optimization by balancing the accuracy and diversity objectives explicitly. Moreover, all base JIT learners are combined adaptively using a finite mixture mechanism. The proposed method is applied to an industrial rubber mixing process for Mooney viscosity prediction, and the experimental results demonstrate its effectiveness and superiority over traditional soft sensor methods.

Developing cost-effective electrocatalyst for oxygen evolution reaction (OER) and elucidating the structural transformation is urgent but remains a significant challenge. Here, we report a scalable approach to prepare well-defined Ni nanoparticles supported by nitrogen-doped carbon (Ni/NC), which possess superior catalytic activity and durability for OER, especially for the sample pyrolyzed at 600 °C. Moreover, the dynamic surface reconstruction of as-prepared catalysts during OER was detailedly investigated by ex-situ characterizations and operando X-ray absorption spectroscopy combined with the difference method that is a novel technique to probe the subtle structural changes. Our findings demonstrate that a surface oxidation to Ni(OH)2 on Ni nanoparticles occurs at the beginning of OER, and then a reversible phase transitions between Ni(OH)2 and NiOOH depends on the applied potential. Thus, this work develops a new method for preparing low-cost Ni-based electrocatalyst and sheds light on the direct observation of surface structure evolution during the OER.

Ni3S2/rGO (reduced graphene oxide) nanoparticles ensemble has been synthesized on the nickel foam as the supercapacitor electrode material by a facile microwave irradiation route. The resultant Ni3S2/rGO electrode exhibits superior capacitive performance, which is severalfold that of the bare Ni3S2. Especially, the Ni3S2/rGO electrode with 20 mg GO precursor (Ni3S2-20) shows highest areal and mass specific capacitances of 1.96 F cm−2 and 1192 F g−1 among all the studied samples, respectively, at the current density of 2 mA cm−2, and the capacitance can be retained to 95.4% after 10,000 cycles at the current density of 10 mA cm−2. A supercapacitor device fabricated by the Ni3S2-20 as both cathode and anode delivers a wide potential window in the range of 0–1.62 V, high areal and mass specific capacitances of 553.2 mF cm−2 and 179.6 F g−1 at the current density of 2 mA cm−2, respectively, together with a high energy density of 67.9 Wh kg−1 at the power density of 535.7 W kg−1. The design of fast and facile synthesis strategy can offer a new insight into developing novel composite electrodes composed of carbon-based materials and pseudocapacitor materials for emerging energy storage applications.

Transitional metal phosphides (TMPs) have been attracted much attention as potential anode materials for lithium-ion batteries, due to their high theoretical capacity, good thermal stability and low cost. In this work, a rational design of multiwalled carbon nanotubes (MCNTs) modified porous CoP/carbon composite (CoP/C@MCNTs) has been realized using metal–organic framework as templates. The CoP/C@MCNTs hybrids with small CoP nanoparticles embed into the three-dimensional carbon skeleton are well incorporated with MCNTs. Owing to their unique architecture, the as-prepared CoP/C@MCNTs composite exhibits promising lithium storage performance with a reversible capacity of 547.5 mAh g−1 at a current density of 500 mA g−1 after 200 cycles and a discharge capacity of 290.2 mAh g−1 can still be maintained at a high current density of 3000 mA g−1. We believe that the interesting strategy for synthetic method in this work can open up a way to design other TMPs-based anode materials.

In this work, the evolution of magnetic ground state and exchange bias (EB) with Al substitution in Ni50Mn37Sb13-xAlx Heusler alloys was investigated in detail. Al doping reduces the cell volume, enhancing antiferromagnetic interactions between Mn atoms and changing the ground state from “reentrant” spin glass (RSG) to spin glass. The conventional EB increases greatly from 314 Oe for x = 0 to 6682 Oe for x = 10. More interestingly, the zero-field-cooled EB begans to emerge at x = 6 where RSG is surppressed and reaches a maximum value at x = 8. These results imply that tuning cell volume provides an effective way to adjust the strength of exchange interaction and further modulate EB in Ni-Mn-based Heusler alloys.

A systematic investigation on the structure, magnetism, magnetocaloric effect, and critical behaviors of multiferroic Lu2NiMnO6 synthesized by sol-gel method are reported. This compound crystallizes in a monoclinic structure with the space group P21/n. Upon decreasing temperature, a single magnetic transition from paramagnetic to ferromagnetic phase has been observed, around which considerable magnetic entropy changes can be obtained. Besides, evaluation of the critical exponents are performed using various techniques, like the modified Arrott plot, Kouvel-Fisher method and critical isotherm analysis based on the magnetic data around magnetic transition temperature. The obtained critical exponent values are found to be coincided and comparable with those predicted by the mean-field model, which are also confirmed by the single scaling equation: m = f±(h), where m and h are the renormalized magnetization and field, respectively by observation of isotherm M(H) curves below and above the critical temperatures collapsing into two independent universal branches. The exponents determined in this study are in good agreement with those calculated from the renormalization group approach for a three-dimensional system coupled with the attractive long-range interactions between spins that decay as J ( r ) ∼ r − ( 3 + σ ) with σ = 1.325.

Ternary metal oxides have attracted much attention in energy storage fields. Herein, tantalum-based oxides MTaO4 (M = Al, Cr and Fe) are synthesized by a facile co-precipitation method, and their performance as lithium-ion battery anodes are evaluated. Among them, the FeTaO4 electrode presents superior electrochemical performance compared to the MTaO4 (M = Al and Cr) and a reversible capacity of more than 200 mAh g−1 can be maintained after 100 cycles, while a capacity of 53.6 and 128.9 mAh g−1 can be obtained at the same condition for AlTaO4 and CrTaO4, respectively. The explanation that FeTaO4 exhibits the excellent electrochemical performance in MTaO4 (M = Al, Cr and Fe) are further discussed.

In this study, a new pressurized weighted-sum-of-gray-gases (WSGG) model of a H2O/CO2 gas mixture under pressurized conditions was proposed to calculate the radiation heat transfer of various pressurized combustion equipment. The new WSGG model and its parameters, which are suitable for a pressure range of 1–30 bar, was developed based on the statistical narrowband (SNB) model of EM2C laboratory. Moreover, its temperature range is 500–2500 K, path-length range is 0.001–60 m, and the range of the molar ratio for H2O/CO2 is 0.125–4. Therefore, the new WSGG model is suitable for many fuels under pressurized conditions. The one-dimensional case results demonstrate that the new WSGG model can well predict the radiation heat transfer of the gas mixture under pressurized conditions compared with the benchmark model. In addition, the new model was used to study the effect of pressure on the radiation heat transfer of the gas mixture. The results show that increasing the pressure within a certain range could enhance the radiation heat transfer of the gas mixture, and this effect was also associated with the temperature, the molar ratio and the path-length. In conclusion, the new WSGG model can be applied to the calculation and research of radiation heat transfer in pressurized combustion chambers, such as pressurized boilers, gas turbines, internal combustion engines and aircraft engines.

The development of the stereolithography technique for the additive manufacturing of silica glass has brought revolutionary change in glass manufacturing. Here, we demonstrate the fabrication of 3D luminescent transparent glass parts manufactured by the stereolithographic technique together with solution impregnation and high temperature sintering. Prefabricated glass parts with nanopores were prepared by the stereolithography technique and debinded and pre-sintered at first. To functionalize the additive manufactured glass with photoluminescence, Eu3+, Tb3+ and Ce3+ ions were doped with a solution impregnation method and further sintered at high temperature. The photoluminescence from these rare earth ions in the blue, cyan and red spectral region can be facilely generated by illumination with a 254 nm UV lamp. Furthermore, we developed a space-selective doping method that enables the doping of different ions in different parts of a silica glass in a space-selective fashion, resulting in a multicolor luminescent glass object giving distinguishable luminescence from each part.

Compared with parts fabricated via traditional methods, such as injection or compression molding, polymeric parts produced by 3D stereolithography (SLA) have poorer mechanical properties. Here, we demonstrate a cross-linking strategy used in the coating field to attain long chains for resin pre-polymerization to obtain final resin parts which can expand the application of SLA. Isophorone diisocyanate (IPDI), 2-hydroxyethyl methacrylate (HEMA) and polyethylene glycol (PEG)-based prepolymer have long chains, making it easier for them to form dense structures. However, the prepolymer has high viscosity and can solidify in the absence of a laser. Thus, three kinds of adjuvants were added to dilute the prepolymer to make the slurry suitable for 3D-printing. Slurries were cured with different laser powers and scanning speeds. Diluents are found to affect the curing properties differently. With the diluent 2-hydroxyethyl acrylate added into the prepolymer, shrinkage of printed parts is lower than 1.3%. With the diluent ethylene glycol monophenyl ether, the density range of printed parts is between 1.187 g cm−3 and 1.195 g cm−3, which is higher than that of commercial PVC and PET. The three resins vary in density and hardness within a small range when the scanning speeds change. A relatively flat surface, high density and hardness can be obtained when the laser power is at 195.5–350 mW. Resin with this cross-linking strategy can expand the underutilized stereolithography's application from prototyping to actual parts by producing more functional components with excellent performance.

Extreme magnetoresistance in nonmagnetic compounds has received considerable attention because this phenomenon challenges the classical understanding of electron transport under a magnetic field. In this study, YBi, which crystallizes in a NaCl-type structure, was synthesized via self-flux method to study its magnetotransport properties and electronic structure. Under zero magnetic field, metallic behavior was observed in the whole temperature interval ranging from 2 to 300 K. Interestingly, extreme magnetoresistance and a resistivity plateau developed when the applied magnetic field was increased; the magnetoresistance reaches 0.8 × 105% at 9 T and 2 K. Multiple bands including one electron pocket and two hole pockets revealed by Kohler's rule and first-principle calculations were responsible for the transport processes. Moreover, the hidden band inversion was also uncovered, which suggests the existence of a topological nature in this compound. The contribution of a single Fermi pocket and the combination thereof for magnetotransport indicate that electron–hole compensation plays an important role in determining the electric properties. All these results point towards YBi being a semimetal member of the RPn family (R = rare earth; Pn = Sb and Bi).

Additive manufacturing of silica glass by stereolithography is a new technology. Improving the efficiency of this technology is an important issue. In this work, a stereolithography system using top-down approach and a compatible suspension for this approach was developed. The debinding behavior of the green part (the solidified suspension) was discussed in detail based on the results of thermogravimetric analysis and Fourier transform infrared absorption spectroscopy. A fast heat treatment within 16 hours was adopted for debinding and sintering of the green part which took only 1/3 of the time of previous report. Designed glassware which could not be processed by conventional technologies was manufactured in this way, and the products showed similar properties with fused silica, as confirmed by X-ray diffraction and UV-vis-IR spectrometer.

Graphite modified AlNbO 4 composite (ANO/G) with monoclinic structure is successfully synthesized using co-precipitation method. The electrochemical measurements show ANO/G exhibits excellent structural stability during the discharge/charge process and ANO particles anchored on graphite effectively improve the capacity of AlNbO 4 . Compared with bare ANO, the ANO/G delivers an initial capacity of 374.8 mAh g −1 and retains reversible 0.67 Li per unit formula after 80 cycles. The lithium-ion reaction with AlNbO 4 mechanisms are proposed and Li + inserted into the lattice and formed the Li x AlNbO 4 when discharging, and recover during the charging process.