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In the present work, transparent and anti-fogging AlPO4-5 films were prepared on glass substrates using a novel developed process. The process entails a simple in-situ sol-gel followed by vapor phase transport. The in-situ sol-gel process was implemented by coating the precursor sols for the synthesis of AlPO4-5 on the glass substrates successively using the spin-coating method. The films and powders scribed from the films were characterized by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). The unique films were composed of oblique oriented nano-flake AlPO4-5 crystals with the thickness of about 20 nm. The formation of nano-flake crystals can be ascribed to the high concentration of the precursors, resulting in the formation of a supersaturation system. The obtained films showed high antifogging performance due to the superhydrophilicity with a water contact angle of lower than 1.0°. The silicone oil contact angle was also low about 8.2°. In addition, heteroatom-substituted AlPO4-5 films showing different colors can be obtained easily by simply adding transition metal ions in the phosphate acid solution during the preparation that can extend the application of the method for different coating demand.

The reaction behaviour and mechanism of carbon and mould fluxes during the heating process were deeply considered through TG-FTIR, XRD, DSC, and SEM techniques. The results showed that: there were ...

MnZn ferrites and their magnetic, electrical, and optical properties make them highly suitable in a number of applications. These ferrites are used in electronic applications, magnetic fluids, and household appliances such as washing machines, refrigerators, and microwave ovens. This paper focuses on a hydrothermal method used to prepare a bayberry spherical manganese–zinc ferrite (Mn0.5Zn0.5Fe2O4), its surface was coated with dopamine (Mn0.5Zn0.5Fe2O4@PDA) and then carbonized to obtain the core–shell structure C-Mn0.5Zn0.5Fe2O4@PDA. Preliminary results show that carbon-coated manganese–zinc ferrite with saturation magnetic properties and coercivity increased from 99 emu and 66.01 Oe to 138 emu and 104.85 Oe, respectively. In addition, the carbonized Mn0.5Zn0.5Fe2O4@PDA (C-Mn0.5Zn0.5Fe2O4@PDA) exhibited favorable microwave absorbing performance with minimum reflection loss (RLmin) of − 17.56 dB and also revealed that the broadest effective absorption bandwidth (RLmin ≤ − 10 dB) 5.36 GHz (11.70–17.06 GHz) can be achieved at 2.0 mm.

Ferroelectric polarizationhas been considered to be an key factor to tune the structural and photoelectric properties of perovskites and their heterostructures. While there has been growing researches made in the novel phenomena originating from interface formed between oxide perovskites, the effects of ferroelectric polarization on the electronic properties of halide perovskites and their heterostructures are rarely studied. Herein, by using first-principles calculations, all-inorganic halide perovskite heterostructure composed of 3D perovskite tetragonal CsPbBr3 and 2D Ruddlesden-Popper (RP) perovskite Cs2PbI2Cl2 is constructed for disclosing the relationship between the intrinsic polarization of tetragonal CsPbBr3 and electronic band structure of heterostructure. Cs atoms and Pb atoms of tetragonal CsPbBr3 in heterostructure are artificially moved away from the equivalent centers to simulate increased polarization. Our results show that with the spontaneous polarization of tetragonal CsPbBr3 increasing, the bandgap of heterostructure decreases, and the band alignment switches from staggered type-II to broken-gap type-III. Moreover, large cation-anion displacements along z-direction in tetragonal CsPbBr3 can be observed when tensile strains (≥5%) are applied, indicating a increased ferroelectric polarization, which also facilitates the decreasing of bandgap in heterostructure and the type-II-type-III transition of band alignment. Our study suggests that control over the polarization of ferroelectric materials is of great importance to tune the photoelectric properties of perovskite-based devices.

Recently, stretchable and wearable health monitoring equipment has greatly improved human’s daily life, which sets higher demands for portable power source in stretchability, sustainability, and biocompatibility. In this work, we proposed a stretchable triboelectric nanogenerator (TENG) based on stretchable poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/porous carbon hybrid for oxyhemoglobin saturation (SpO2) monitoring. To combine advantages of carbon material for its high conductivity and organic electrode for its high stretchability, we spin-coated a solution of PEDOT:PSS/porous carbon onto a plasma-treated pre-stretched Ecoflex film to fabricate a stretchable electrode with rough surface. Due to its roughness and high potential difference with the dielectric material, the stretchable-electrode-based TENG exhibited better performance compared to the pristine TENG based on carbon or PEDOT:PSS material. The output voltage and current reached up to 51.5 V and 13.2 µA as the carbon concentration increased. More importantly, the performance further increased under large strain (100%) which is suitable for wearable systems. Finally, the device demonstrated its application potential for powering a flexible blood oxygen monitor. This simple and cost-effective method can enhance the stretchability and stability of organic/inorganic electrode-based TENG, which paves the development of high-performance stretchable TENG.

The nanosecond short pulse generator, which operates continuously at MHz repetition rates, plays an important role in high-energy accelerators, pulsed laser modulation, electromagnetic biological effects, and other fields. Pulse-forming lines based on gas spark gap are the main means to generate high-voltage nanosecond short pulses; but due to electrode ablation, it is difficult to operate at MHz repetition rates. The topologies based on the fully controlled semiconductor device can output multimode nanosecond pulse. But it is limited by the gate driver ability and system stray loss, so it is difficult to directly generate flexible and adjustable nanosecond short pulse with MHz repetition rates. In order to overcome the above shortcomings, this article proposes the Blumlein-based LC underdamped oscillation boost circuit and the Blumlein stack topology to achieve high voltage gain. And, the voltage wave process can be adjusted by controlling the switching sequence to change operating mode. Finally, multimode operation such as positive polarity, negative polarity, bipolar and pulse duration modulation can be realized with MHz repetition rates and high gain voltage.

A loudspeaker is a device that converts electrical energy into acoustic energy by coupling between electrical impedance, mechanical impedance, and radiation impedance. The loudspeaker electro-mechanical-acoustic coupling model provides the experimental feasibility to measure the characteristic parameters. In this paper, an economical and practical measurement method of loudspeaker mechanical impedance is proposed. First, the mathematical relationship between loudspeaker electrical impedance and mechanical impedance is obtained based on the loudspeaker electro-mechanical-acoustic coupling model. Second, two electrical impedances with different known radiation impedance are measured by using a developed measurement system. Finally, the real and imaginary parts of the mechanical impedance are obtained according to the mathematical relationship. This method neither assumes that the loudspeaker mechanical impedance is constant in a frequency band nor does it build FEM models based on structural parameters. A loudspeaker is measured by using a developed measurement system. The result shows that the mechanical impedance and the force factor are functions of frequency. Moreover, a radiation impedance measurement is performed to verify the feasibility and accuracy of the proposed method.

Aims: In this work, an improved control Volume finite element method (ICVFEM) is proposed and implemented for thermoelastic analysis in functionally graded materials (FGMs) at a steady state. Methods and Results: Different from the conventional CVFEM, the sub-control Volume used in the proposed method is circular in the intrinsic coordinate. The advantages of the new integral domain are: (i) the complex integration path can be avoided: (ii) the method is very suitable for many types of elements. High-order shape functions of eight quadrilateral (Q8) elements are used to obtain the unknown variables and their derivatives. Besides, material properties in a functionally graded structure are calculated by the high-order shape functions based on the properties defined at the node. Conclusion: To verify the convergence and accuracy of the proposed method, three numerical examples with analytical solutions are illustrated by using the conventional CVFEM and FEM at the same time.

Autoignition characteristics of a four-component surrogate fuel(M2) were investigated in a heated rapid compression machine over a wide range of conditions. The near-term light surrogate M2 developed for marine diesel fuel was formulated in our previous study containing 17.3% n-hexadecane, 5.93% 2,2,4,4,6,8,8-heptamethylnonane, 30% decalin and 46.77% 1-methylnaphthalene by mole fraction. Ignition delay times (IDTs) of gas-phase M2/N2/O2 mixture were measured at pressures of 7, 10, 15 and 20 bar over the temperature range from 675 K to 914 K for the equivalence ratios (ER) of 0.5, 1 and 1.5. NTC behaviours within the temperature of 730–850 K and two-stage ignition phenomena were observed. The effects of operating conditions such as pressure, equivalence ratio and oxygen content were systematically studied, and correlations of total IDTs and first-stage IDTs were performed to further quantitatively reveal the IDTs dependence on the above parameters. Reasonable modifications were made to a literature mechanism to improve its predicting quality. The simulation results using the modified model could satisfactorily reproduce the IDTs under the test conditions, and the model is also able to capture the ignition delay dependence on pressure and fuel/oxygen content. A brute force sensitivity analysis at the low temperature (680 K) and the NTC temperature (780 K) was carried out to identify the key reactions that govern the ignition event of surrogate M2.

Herein, from the perspective of gaining the excellent microwave absorption performances, we decorated flower like MoS2 nanoflates on the cubic phase NiS2 and adjusted the adherent MoS2 content to construct different NiS2@MoS2 core-shell structures via a facile hydrothermal process. Besides, we also properly regulated the complex relative permittivity originated from NiS2@MoS2 content in the PVDF to optimize impedance matching behaviors. And the real and imaginary parts of permittivity gradually increase with the increase content of NiS2@MoS2 composite in PVDF and decrease of MoS2 supported on the surface of NiS2 For the filler content of 20 wt%, the NiS2@MoS2-0.065 composites covered with moderate MoS2 nanosheets exhibit an optimal reflection loss of −57.35 dB at 8.16 GHz and effective absorption bandwidths of 4.0 GHz. Moreover, we believe that as-synthesized NiS2@MoS2 core-shell structure is a reliable strategy to facilitate advancements of microwave absorbers.

Methanol is an attractive oxygenate increasingly used as primary fuel for dual-fuel combustion technology yielding beneficial thermal-efficiency and emissions in modern engines. As such, it is significant to fundamentally understand the autoignition behavior of methanol/diesel mixtures. This study measured the ignition delay times (IDTs) of methanol/diesel blends with different mixing ratios (30%, 50%, 70% methanol by mol.) on a heated shock tube and a heated rapid compression machine at temperatures of 650−1450 K, pressures of 6−20 bar, and equivalence ratios of 0.5, 1.0 and 2.0. The typical two-stage ignition characteristics with the negative temperature coefficient response were observed for dual-fuel mixtures. In general, both the total and first-stage IDTs decrease with the increment of pressure and equivalence ratio as well as diesel proportion in mixtures. The simulation results performed with a published detailed mechanism in conjunction with a tri-component diesel surrogate demonstrate generally good agreement with the experimental data at all test conditions. Moreover, a crossover of IDTs occurs at a higher temperature (~1500 K) for varying equivalence ratios, and experiment and simulation both exhibit a non-linear mixing effect of methanol addition on diesel ignition. Interestingly, simulation results clearly suggest a crossover (~940 K) for mixtures with varying methanol content at an intermediate-temperature, where the IDT of the mixture with a lower methanol ratio becomes longer as the temperature is higher than that of the crossover. Furthermore, brute-force sensitivity analyses assisted with reaction path analysis were conducted to gain deeper insights into the autoignition chemistry of dual-fuel mixtures, especially for the chemical interaction between both fuels during the low-temperature oxidation process. It is found that methanol hardly generates •OH, whereas •OH is mainly produced by the low-temperature reaction pathways of diesel. Thus, •OH is the bridge for both fuels during the ignition process. At the high methanol ratio, the H-abstraction of diesel is mainly via •HO2 while CH3OH consumes a large percentage of •OH. Consequently, the competition between methanol and diesel for •OH radicals inhibits the overall reactivity of reaction network. In addition, the original data reported here lay a foundation for the development and validation of more accurate and robust dual-fuel kinetic schemes.

A superconducting quadrupole magnet based on the Canted-Cosine-Theta (CCT) type coil with a gradient field of 40 T/m and a bore diameter of 60 mm has been designed for the preresearch of two projects of high intensity accelerator facility (HIAF) and accelerator driven subcritical system (ADS). The magnet is comprised of two-layer coils embedded in the formers and the end plates for locating. The coil formers made of aluminum alloy are machined with grooves according to the drive equations of CCT for placing the wires. The existence of ribs between two adjacent wires can avoid accumulation of the electromagnetic force. It is important to take the mechanical design for the complex structure to avoid tensile stresses on the conductor and confine the stresses within a reasonable value. The stress analysis for the quadrupole magnet has been carried out considering the thermal shrinking due to cool down as well as the electromagnetic force on the coil. This paper reports the detailed stress analysis for the CCT quadrupole magnet structure, discusses the calculating results, and gives a reasonable mechanical design.

ZnO nanorod arrays (NRAs) were fabricated on polyester fabrics (PFs) by a two-step method and modified with Ag by magnetron sputtering. The photogenerated charge transport properties of the Ag/ZnO nanorod heterojunctions were studied by a self-made Kelvin probe system and a surface photovoltage (SPV) test system. The measured work functions (WFs) of the deposited Ag and ZnO nanorod are 4.67 and 5.56 eV, respectively. The SPV spectra indicate that the direction of the inner electric field is from the Ag layer to the inner of the ZnO nanorod. The enhancement of light absorption by the local surface plasma resonance (LSPR) effect of Ag/ZnO NRA was observed by Raman microspectroscopy and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity of the Ag/ZnO NRA-functionalized PFs was evaluated by the photocatalytic degradation of Rhodamine B (RB) solution under visible light. The full photo-oxidation of RB and the outperforming ZnO NRA-coated PFs demonstrate that the enhanced photocatalytic performance of Ag/ZnO NRA-coated PFs results from the cooperation of the inner electric field of the Ag/ZnO nanorod heterojunction and Ag LSPR.

Micro-supercapacitors with high power density and stability promise emerging energy storage devices. However, their relatively low energy density and poor mechanical stability largely restricts their application. Here, we report an all-in-one planar micro-supercapacitor (MSC) using ZnO nanosheets anchored on the porous and 3D laser-induced porous graphene foams (ZnO@LIG) as the electrode materials. Due to the 3D networks, the hybrid electrode exhibits fast charge transfer and diffusion channels. More importantly, the hybrid approach can simultaneously take advantage of double-layer capacitance and faradaic energy storage mechanisms. The ZnO@LIG electrode displays a high specific capacitance of 14.7 F cm−2, remarkable rate capability and cycling stability. Furthermore, the MSC showcases high energy density (10.0 Wh kg−1), high power density (0.5 Wh kg−1), long-term stability, and excellent mechanical stability upon bending. The excellent performance parameters of the MSC make it one of the promising micropower sources for flexible microelectronics.

The nickel-doped bis [3-(trimethoxysilyl) propyl] amine (BTPA) derived membrane has a microporous coordinated network that has high potential to be an ideal separation barrier for methanol-toluene azeotropic mixtures via the pervaporation process. Ni-BTPA membranes were modified by employing a nickel dopant over amine groups in mole ratios (mol/mol) that ranged from 0.125 to 0.50. The incorporation of different amounts of nickel dopant into flexible amine-rich organosilica precursors of BTPA increased the rigidity and resulted in a porous structure with a large specific surface area (increased from 2.36 up to 282 m2 g-1) and a high pore volume (from 0.024 up to 0.184 cm3 g-1). Methanol-toluene separation performance by the nickel-doped BTPA (Ni-BTPA) membranes was increased with increases in the nickel concentration. Ni-BTPA 0.50 showed separation performance that was superior to other types of membranes, along with a high-level of flux at 2.8 kg m-2 h-1 and a separation factor higher than 900 in a 10 wt % methanol feed solution at 50 °C. These results suggest that the balance between the microporosity induced by amine-nickel coordination and an excessive amount of nickel-ion facilitates high levels of flux and separation of methanol.

The ignition delay times (IDTs) of n-alcohol/diesel blends were measured in a heated shock tube (ST) and a heated rapid compression machine (RCM). Three sets of blends were formulated to investigate the effect of n-alcohol (the volume ratio of n-alcohol/diesel being 20%/80% for four blends), cetane number (CN = 43, the volume ratio of n-alcohol/diesel being 20%/80% ethanol/diesel, 20.5%/79.5% n-propanol/diesel, 23.5%/76.6% n-butanol/diesel, 25.8%/74.2% n-pentanol/diesel), and oxygen content (mass fraction of oxygen wO2 = 6.65%, the volume ratio of n-alcohol/diesel being 20%/80% ethanol/diesel, 25.6%/74.4% n-propanol/diesel, 31.4%/68.6% n-butanol/diesel, 37.2%/62.8% n-pentanol/diesel) on the autoignition characteristics. In the RCM temperature region, the IDTs decrease with increasing n-alcohol chain length from ethanol to n-pentanol for all three sets of blends, while those in the ST temperature region show indiscernible variations. Interestingly, the intersection of IDTs for ethanol/diesel blend with other n-alcohol/diesel blends is observed when the temperature is below ~700 K. A recently-released detailed mechanism from the CRECK modeling group was used to predict the experimental results. The simulations show relatively good agreement with high-temperature (HT) ignition data, while the mechanism pronouncedly overpredicts the reactivity of blends at low-to-intermediate temperatures. Sensitivity analyses at three temperatures of 675 K, 800 K, and 1300 K were conducted to identify the dominant reactions during the autoignition of 20% n-alcohol/80% diesel blends and to kinetically elaborate and discuss the discrepancies between simulations and experiments. At the end, a preliminary mechanism tune-up was carried out grounded on the sensitivity analyses. The improved mechanism regains its predictive ability for IDTs of 20% n-butanol/80% diesel blend at RCM temperatures, while fails to precisely simulate the remaining three blends.

Along with the development of silicon carbide (SiC) sensors and electronic devices for operation at 500°C, compatible packaging technologies are needed for long term high temperature test and deployment of these sensors and electronic devices. 96% Al2O3 ceramic is a good electrically insulating material with acceptable dielectric constant and low dielectric loss over wide temperature and frequency ranges. This paper presents a packaging system for low power integrated circuits including a prototype 8-I/O chip-level package and printed circuit board (PCB) based on 96% Al2O3 ceramic substrates and Au thick-film metallization for 500°C applications. The details related to designs of packages and PCBs, packaging materials, and specific packaging step recipes including wire - bonding and die-attach, are presented. Some test results of this prototype packaging approach applied to SiC integrated circuits at 500°C are reviewed.

At HiTEC 2018, NASA Glenn Research Center reported the first demonstration of yearlong 500 °C operation of ceramic-packaged “Generation 10” ~200-transistor integrated circuits (ICs) based on two-level interconnect silicon carbide (4H-SiC) junction field effect transistors and resistors (JFET-R). This HiTEC 2021 submission updates on-going efforts at NASA Glenn spanning two subsequent prototype IC generations “11 and 12” to increase both complexity and durability of these ICs. Increased chip complexities of around 1000 transistors/chip for Gen. 11 and near 3000 transistors/chip for Gen. 12 are made possible by reductions in minimum layout feature sizes (including resistor width shrinkage from 6 μm to 2 μm) coupled with enlarged die size (from 3 × 3 mm to 5 × 5 mm). Gen. 11 ICs electrically tested to date include an 8-bit delta-sigma analog to digital converter (ADC) as well as upscaled random access memory (RAM) and nearly 1 kbit read only memory (ROM). However, Gen. 11 prototype ICs exhibited significantly lower yield and durability than Gen. 10 ICs. Development of revised processing is being investigated towards mitigating these issues in subsequent Gen. 12 fabrication run currently in progress.

The low-temperature hydrogenation of CO2 to methanol is of great significance for the recycling of this greenhouse gas to valuable products, however, it remains a great challenge due to the trade-off between catalytic activity and selectivity. Here, we report that CO2 can dissociate at sulfur vacancies in MoS2 nanosheets to yield surface-bound CO and O at room temperature, thus enabling a highly efficient low-temperature hydrogenation of CO2 to methanol. Multiple in situ spectroscopic and microscopic characterizations combined with theoretical calculations demonstrated that in-plane sulfur vacancies drive the selective hydrogenation of CO2 to methanol by inhibiting deep hydrogenolysis to methane, whereas edge vacancies facilitate excessive hydrogenation to methane. At 180 °C, the catalyst achieved a 94.3% methanol selectivity at a CO2 conversion of 12.5% over the in-plane sulfur vacancy-rich MoS2 nanosheets, which notably surpasses those of previously reported catalysts. This catalyst exhibited high stability for over 3,000 hours without any deactivation, rendering it a promising candidate for industrial application. The catalytic hydrogenation of CO2 to methanol is a crucial reaction for the recycling of this greenhouse gas, although the selection and related performance of commercial catalysts is still limited. Now, the authors introduce sulfur vacancy-rich MoS2 nanosheets as a superior catalyst for this process, rivalling the commercial benchmark system.

Thanks to their excellent corrosion resistance, superior mechanical properties and good biocompatibility, titanium (Ti) and Ti alloys are extensively applied in biomedical fields. Pitting corrosion is a critical consideration for the reliability of Ti and Ti alloys used in the human body. Therefore, this article focuses on the pitting corrosion of Ti and Ti alloys, which introduces the growth stages of pitting corrosion and its main influencing factors. Three stages, i.e. (1) breakdown of passive film, (2) metastable pitting, and (3) propagation of pitting, are roughly divided to introduce the pitting corrosion. As reviewed, corrosive environment, applied potential, temperature and alloy compositions are the main factors affecting the pitting corrosion of Ti and Ti alloys. Moreover, the pitting corrosion of different types Ti alloys are also reviewed to correlate the types of Ti alloys and the main factors of pitting corrosion. Roughly speaking, β-type Ti alloys have the best pitting corrosion resistance among the three types of Ti alloys.

In this research, thermoplastic polyimide (TPI) were welding via friction stir spot welding (FSSW) in order to evaluate the feasibility of the technology. The welding tool with a tri-flute pin was used for keeping the welding effectiveness. The effect of the rotation speed and dwell time on the microstructure and shear strength was studied. The results shows that the number of gap defects between the shoulder affect zone and the pin affect zone decreased with the increase of the rotation speed. The boundary of the shoulder affect zone and the pin affect zone was no clear when increasing the dwell time from 10 s to 20 s. Long dwell time could increase the mixing time and reduce the materials viscosity, which made the structure was denser. The maximal shear strength was obtained 85.5% of the base materials. The differential scanning calorimetry (DSC) results indicated that the melting behaviour of different regions was no obvious difference. It indicated that FSSW had a feasible and potential technology to join the high temperature resistant engineering plastics.

The volatilization problem of mold fluxes extremely affects their physicochemical properties and then the quality of steel shells and casting process. Therefore, in this paper, the qualitative and quantitative analysis of volatiles in the most commonly used CaO–SiO2–CaF2–Na2O slag was conducted with thermogravimetric analyzer–mass spectroscopy (TG–MS), X-ray diffraction (XRD), scanning electron microscope with energy-dispersive spectroscopy (SEM–EDS) and FactSage, followed by giving the mechanism of fluorine volatiles in mold fluxes during the actual casting process. The results showed that the fluorine volatiles were formed when the temperature was higher than 1000 °C. The species of fluorine volatiles were SiF4 and NaF. Moreover, the total volatiles content of fluorine for sample B with Na2O was 9.41%, being much larger than that of 1.53% for sample C without Na2O. For sample B, the content of NaF was much larger than that of SiF4. It was because of the reaction between Na2O and CaF2. SiF4 with a low boiling point of − 65 °C could pass through the slag layer and enter air directly. However, when NaF passed through the sinter layer or powder slag layer, NaF would convert into liquid or solid state, reenter molten slag and continuously repeat this process due to their high melting point of 993 °C.

Hybrid microporous aminosilica membranes have been successfully synthesized via doping with Ag-, Cu- and Ni- into dense bis[3-(trimethoxysilyl)propyl] amine (BTPA) membranes, which creates micropores via the crosslinking between donor pairs of electrons in the amine moiety and electron acceptors in the empty “d” orbital of the transition metal. The formation of micropores within the coordinated covalently bonded compound was investigated via Ultraviolet-Visible spectroscopy (UV-Vis), Fourier Transform Infrared spectroscopy (FT-IR), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and the isotherms of N2 and CO2 sorption. Values for the surface area and pore volume of the metal-doped BTPA were both expanded by increasing the metal coordination affinity to 214 m2 g−1 and 0.185 cm3 g−1, respectively. The effect of metal doping on the membrane separation performance was evaluated using a single-gas permeation system and the activation energy of permeance was measured. Gas permeation was increased following the doping process due to the formation of a microporouse structure on the order of Ni-BTPA > Cu-BTPA > Ag-BTPA > BTPA, which corresponds to higher affinity for metal coordination. Permeation behavior was dominated by the molecular sieving effect that showed a high level of H2 permeance at 4.45 × 10−6 mol m−2 s−1 Pa−1 with a H2/SF6 permeance ratio that reached 15 500, which is indicative of a defect-free membrane. By comparison with Cu-BTPA (14.8 kJ mol−1), Ag-BTPA (19.5 kJ mol−1), and BTPA (31.1 kJ mol−1) membranes, the Ni-BTPA membrane showed the lowest value for CO2 activation energy (8.9 kJ mol−1), which can be ascribed to the microporosity that was formed by a higher coordination interaction. The nickel-doped BTPA achieved high levels of both permeance of N2 and selectivity for N2/SF6 at 3.75 × 10−7 mol m−2 s−1 Pa−1 and 1900, respectively.

Three-dimensional (3D) adsorption materials have attracted ever-increasing interest as a cost-effective tool to remove antibiotics from water. However, how to effectively enhance the adsorption capacity of the adsorbents is still a great challenge. In this study, a novel method for fabricating 3D porous carbon nanofiber/graphene oxide composite aerogels (PCNF/GOAs) with an adjustable pore structure was developed for antibiotic removal from water using electrospinning-liquid assisted collection technology. By adding poly(methyl methacrylate) (PMMA) as a pore-forming agent, the volume of pores corresponding to the tetracycline (TC) size (0.8–2 nm) increased twelve-fold, and the adsorption capacity increased nine-fold. To evaluate the feasibility of PCNF/GOAs as a potential adsorbent for antibiotic removal, batch and fixed-bed experiments were conducted. The results showed that PCNF/GOAs effectively removed TC from water over a wide pH range (4–10), and the maximum adsorption capacity was more than 900 mg g−1 at pH 7. The experimental data for the adsorption of TC onto PCNF/GOAs better fitted the pseudo-second-order kinetic and Temkin models. Due to its self-supporting characteristic, 3D PCNF/GOAs generated lower inlet pressure compared to traditional particle adsorbents in fixed-bed column adsorption. π–π electro-donor–acceptor (EDA) interaction, pore filling and hydrogen bonding are the main possible mechanisms for the adsorption of TC on PCNF/GOAs.

Polyether polyols as a crucial chemical for the synthesis of polyurethanes have attracted much attention, especially for propylene oxide-based polyether polyols due to their ready availability and good structural diversity. In the present work, microreactors configured with a SIMM-V2 micromixer and stainless steel capillary were developed for the continuous and efficient synthesis of propylene oxide-based polyether polyols. For the conversion of propylene oxide higher than 95%, the reaction time was less than 60 s that was significantly shorter than that in a batch reactor. Also, the reaction temperature can be controlled precisely, thereby obtaining high purity polyether polyol products. To identify the maximum performance of the microreactors, while keeping the conversion of PO higher than 95%, the novel process windows of the reactors were determined by investigating the relations of reaction temperature and pressure, reaction temperature and residence time, and feed flow rate and residence time. The results showed that high quality polyether polyols could be easily prepared in the microreactors under flexible operating conditions. In addition, polyether polyols with higher molecular weights could also be prepared by using a two SIMM-V2 configured microreactor. This work showed that the microreactors are promising candidates for the synthesis of polyether polyols in the industry.

Random lasing from CsPbBr3 quantum dots (QDs) prepared by the hot injection method under ambient conditions has been investigated. The lasing characteristics and performance were related to the thickness and aggregation of the QDs film on a glass substrate. The perovskite emitted linear polarized ASE from the edge of the prepared sample as pump energy above a certain threshold, owing to the gain guiding effect. In comparison to the Q-switched Nd:YAG laser, the prepared perovskite random lasers produced a speckle reduced image with a lower contrast of around 0.051. Through temperature-dependent measurements under a surface normal emission configuration, the photon energy of ASE revealed a red shift as the temperature increased and showed a larger characteristic temperature of around 230 K. This result illustrates that the perovskite prepared under ambient conditions can be a promising material for a microcavity laser in the near future.

Detailed high-fidelity kinetic models of fuels are of great significance by providing guidance for the improvement of the combustion performance in engines and promising the reduction of design cycle of new concept combustors. However, the kinetic modeling works on Chinese RP-3 kerosene, the most widely used civil aviation fuel in China, are meager to date. In this study, a kinetic model, including a surrogate fuel and its combustion kinetic mechanism, were developed to describe the combustion of RP-3. Firstly, a surrogate comprised of components n-dodecane, 2,2,4,6,6-pentamethylheptane (PMH), n-butylcyclohexane and n-butylbenzene (22.82/31.30/19.19/26.69 mol%) was proposed based on the combustion property target matching method. These components are all within the typical molecular size (C10-C14) of jet fuels and thereby can potentially improve the ability of the surrogate in emulating the properties that depend on molecular size. Experiments were then carried out in a heated rapid compression machine and a heated shock tube to evaluate the performance of the surrogate in reproducing the combustion behavior of the target fuel over wide conditions. It is found that the surrogate can reproduce the autoignition characteristics of RP-3 very well. A chemical kinetic mechanism was developed to describe the oxidation of this surrogate. This mechanism was assembled using a published n-butylbenzene sub-mechanism and our previous sub-mechanisms for the other pure components, and was assessed against the present experimental data. The results showed that the simulations agreed well with the experimental data under the investigated conditions, demonstrating that the composition of the surrogate and its mechanism are appropriate to describe the combustion of RP-3. The first-stage ignition negative temperature coefficient behavior and the evolution of key radicals were investigated using the kinetic model.

Organic compounds with high theoretical capacity, tunable redox potentials and rich structural chemistry are considered as promising electrode materials for sodium-ion batteries (SIBs). However, organic electrode materials suffer from low electronic conductivity and low structural stability, hindering their practical applications. Thiophene compounds have been well considered in the design of photoelectric materials with improved charge transfer properties. It is envisaged that electron-transfer capability is also essential in addressing the issues of organic electrode materials for SIBs. Herein, sodium thieno[3,2-b]thiophene-2,5-dicarboxylate (STTDC), an organic compound with high electron transfer capability is designed and synthesized. When employed as an electrode material for SIBs, remarkably high electrochemical performance, including large reversible capacity, high rate capability and excellent stability was achieved. A large specific discharge capacity of 430 mA h g−1 is delivered at a current density of 50 mA g−1. A high reversible capacity of approximately 288 mA h g−1 is retained after 4000 cycles at a high current density of 2.0 A g−1. The present work sheds new light on the design of high-performance organic electrode materials.

Carbon-based mesoscopic perovskite solar cells (PSCs) are promising for printable next-generation photovoltaic applications, but the optical properties of their carbon layer limit their light harvesting efficiency. We developed solution-processable indium-tin-oxide (ITO) nanoparticles to replace carbon electrodes for mesoscopic lead-free tin-based PSCs. The ITO electrodes were fabricated via screen printing with 1, 2, 4, 6 and 8 layers corresponding to the thicknesses of 2.1–14.3 μm; tin perovskite (GA0.2FA0.8SnI3) with SnF2 (20%) and EDAI2 (15%) (GA represents guanidinium; EDAI2 represents ethylenediammonium diiodide) was drop-casted on the device to produce a mesoporous structure of FTO/TiO2/perovskite/Al2O3/ITO. The best device achieved a power conversion efficiency of 5.4% with great stability. These solution-processed ITO electrodes are a landmark to shed light on new paths for the commercialization of lead-free PSCs.

The separation of alkane/alkene gas mixtures represents an important yet challenging process in the petrochemical industry to produce valuable chemical feedstocks with sufficiently high purity. These molecules have similar physical properties, making their separation difficult and capital-intensive. The current separation and purification technology relies largely on heat-driven distillations with a huge unit composed of hundreds of trays. Adsorptive separation using porous solids is capable of accomplishing the purification under ambient conditions, offering potential energy and environmental benefits. In particular, metal–organic frameworks (MOFs) hold enormous promise for this separation process in light of their highly tunable pore shape, pore size, and pore surface functionality. In this review article, we provide a comprehensive account of metal–organic frameworks that have been investigated for the separation of alkanes and alkenes with a focus on C2–C3 hydrocarbons. The material design rationale, separation mechanisms, and structure–property relations are highlighted. Finally, the existing challenges and possible design strategies for desirable materials are also discussed.

B2CN was one of the synthesized light element compounds, which was expected to be superhard material with a metallic character due to its electron deficienct nature. However, in this work, we discovered two novel semiconducting superhard B2CN phases using particle swarm intelligence technique and first-principles calculations, which were reported to have three-dimensional and four coordinated covalent diamond-like structures. These two new phases were calculated to be dynamically stable at zero and high pressures, and can be deduced from the previously reported Pmma phase by pressure-induced structural phase transitions. More importantly, unlike the previously proposed metallic B2CN structures, these two new phases combine superhard (the calculated Vickers hardness reached ∼55 GPa) and semiconducting character. The semiconducting behavior of the newly predicted B2CN phases breaks the traditional view of the metallic character of the electron deficient diamond-like B-C-N ternary compounds. By a detail analyzation of the electron localization functions of these two new phases, three-center bonds were reported between some B, C and B atoms, which were suggested to be the primary mechanism that helps the compound overcome its electron-deficient nature and finally exhibit a semiconducting behavior.

High-frequency bipolar high-voltage pulsed electric field can be used in tumor ablation to uniform the electric field distribution in the ablated region and inhibit muscle contraction effectively. Developing a high-frequency bipolar pulsed power generator (HBPPG) with wide range of specifications, such as voltage magnitude, waveform, repetition rate, and pulsewidth, is of great significance for promoting the clinical application of irreversible electroporation. Hence, in this article, a novel modular high-voltage HBPPG circuit topology is proposed for such application. Each module consists of an H-bridge and an isolated inductor. Theoretical analysis, simulation, and experimental results show that this generator perfectly combines the advantages of solid-state Marx and bridge circuit, with high stability and redundancy. The pulse frequency, pulse duration, and waveform can be flexibly adjusted by a controller software algorithm according to load parameters. The viability of the proposed HBPPG is demonstrated by PSpice simulation and equal-scale prototype. The key parameters of the developed HBPPG are as follows: voltage amplitude up to ±10 kV with 500 ns–5 μ s pulsewidths, 500 kHz within the burst, and 10 kHz within the continuation limited by the input high-voltage dc power supply. All the pulse parameters can be programmed arbitrarily.

A transient numerical model was applied to simulating the axial-directional crystallization purification (ADCP) process of gallium (Ga) raw material at different coolant temperatures (Tc), and the evolutions of melt/crystal (m/c) interface shape, temperature distribution and thermal stresses were simulated and analyzed. The results showed that the m/c interface shape, temperature distribution, and thermal stress in the Ga material were determined by the Tc in the crystallizer during the ADCP process. The temperature gradient and thermal stress in the grown Ga crystal increased with decreasing Tc. At Tc=15 °C, the m/c interface shape was flat, and the temperature gradient was ideal. Therefore, the Ga materials with lower thermal stresses and suitable m/c interface shape, and an ideal efficiency of impurity removal were obtained. The purity of Ga reached 6N standard by using ADCP process repeated 6 times at Tc of 15 °C. The results of the simulation showed good agreement with the experimental results.

An Al−3.6Cu−1Li alloy was subjected to room temperature rolling and cryorolling to investigate their effects on microstructure evolution and mechanical properties. The microstructure and aging characteristics of the room temperature-rolled and the cryorolled alloys with 70% and 90% of thickness reductions were studied by microstructure analysis and mechanical tests. The samples subjected to cryorolling with 90% of thickness reduction have high strength and good toughness. This is mainly due to the inhibition of dynamic recovery and the accumulation of high-density dislocations in cryorolled samples. In addition, the artificial aging reveals that the temperature at which peak hardness is attained is inversely proportional to the deformation amount and directly proportional to the rolling temperature. Moreover, bright field images of cryorolled samples after aging indicate the existence of T1 (Al2CuLi) precipitates. This suggests that the high stored strain energy enhances the aging kinetics of the alloy, which further promotes the nucleation of T1 phases.

In this paper, the tribological property of polyimide (PI) resin was improved by adding poly-p-phenylenebenzobisoxazole (PBO) fibers. The effects of PBO fiber volume fraction were studied by mechanics and tribology tests. The fracture and wear surfaces of PBO/PI composites were investigated by using scanning electron microscopy (SEM). The measurement showed that the flexural properties of composites reinforced by 10 vol% PBO fibers were lower than pure PI resin. With the increase of PBO fiber content, the flexural strength was first increase and then decrease. The frictional coefficient and wear rate of the PBO/PI composites varied with the variety of fiber content, and the optimum parameter was obtained at 20 vol%. The dominant wear mechanism and friction process were discussed on the basis of microscopic morphology analysis of wear surface of PBO/PI composite and the counterpart.

A new layered material CsPb2Br5 with great stability and excellent optoelectronic properties has attracted great attention. At present, the luminescent mechanism of CsPb2Br5 is a hot topic. Last ye...

In this study, friction stir processing (FSP) is utilized to fabricate FeCoNiCrAl high-entropy alloy reinforced Al5083 composites. The role of the reinforcement and processing pass on microstructure, microhardness, and wear properties of the composites are studied. The surface of the composites was analyzed via scanning electron microscope. The number of the processing passes acts an important role in the production of the composites via FSP technology. XRD result shows that FSP technology can be used for producing FeCoNiCrAl high-entropy alloy reinforced 5083 aluminum matrix composites which does not contain any harmful intermetallic. The properties of the composites are evaluated by microhardness and wear test. The results show that the composites possess higher microhardness and wear resistance than the Al5083 base alloy and FSPed samples without the FeCoNiCrAl high-entropy alloy particles. In all the composites, the sample produced by 5 passes reveals the highest microhardness, the best wear resistance, and the lowest friction coefficient.

Ammonia (NH3) is receiving increasing attention as an alternative engine fuel due to its carbon-free nature. However, its fundamental combustion characteristics, such as higher autoignition temperature and lower burning velocity compared to conventional hydrocarbons, limit its direct use in traditional engines. To confront this dilemma, hydrocarbon/NH3 blending fuels are seen as one of the most appropriate ways to exploit its advantage and offset its weaknesses. Using n-heptane as a representative of hydrocarbons, this study investigated the effect of NH3 addition on the low-temperature autoignition of n-heptane. The ignition delay times of five n-heptane/NH3 mixtures with NH3 fractions of 0%, 20%, and 40% were measured in a rapid compression machine at temperatures of 635–945 K, pressures of 10 and 15 bar, and equivalence ratios of 1.0 and 2.0. Experimental results show that the n-heptane/NH3 blending fuels exhibit pronounced low-temperature reactivity, and both the total and the first-stage ignition delay times increase with the increase of NH3 fraction. A blending mechanism of n-heptane/NH3 was compiled based on the existing n-heptane mechanism and NH3 mechanism. It is found that the blending mechanism is capable to predict the inhibition effect of NH3 addition on n-heptane autoignition and qualitatively capture the dependence of ignition delay time on equivalence ratio and oxygen mole fraction. Nevertheless, there are significant discrepancies between the experiments and the simulation. Furthermore, kinetic analyses, including species evolution, rate of production and sensitivity of OH radical were conducted sequentially to reveal the autoignition kinetics of NH3/n-heptane blends and the interaction between n-heptane and NH3. Suggestions are provided for the further development of the blending mechanism.

Butanol/diesel blend is considered as a very promising alternative fuel with agreeable combustion and emission performance in engines. This paper intends to further investigate its autoignition characteristics with the combination of a heated rapid compression machine (RCM) and a heated Shock Tube (ST) to acquire a wide temperature region view. The ignition delay times (IDTs) of mixtures of 20% blending (by vol.) of n-butanol to China Stage-VI diesel, referred to as N20, were studied under the pressures of 6/10/15 bar, the equivalence ratios of 0.5–2.0, and a broad temperature range of 670–1300 K. Typical two-stage ignition and NTC behavior of the fuel were identified, and the IDT dependences on the compressed pressure, fuel/oxygen fraction, and the blending ratio were explained thoroughly and quantitively with correlation formulas. Furthermore, this paper expands the study to the effects of butanol structures. Autoignition characteristics of mixtures of 20% blending (by Vol.) of each of the four butanol isomers with neat diesel were investigated experimentally and numerically. The CRECK model was validated against the experimental results and critical reactions controlling fuel ignition were identified for further optimization.

Pore size and connectivity of artificial bone scaffolds play key role in regulating cell ingrowth and vascularization during healing. The objective of this study was to develop a novel process for preparing 3D pore-interconnected open-cell bone substitutes with varying pore sizes. This was achieved by thermal-induced expansion, drying, then sintering the mixture of biphasic calcium phosphate (BCP) and a thermal responsive porogen comprising chitosan (CS) and hydroxypropyl methyl cellulose (HPMC). The interpolymer complexes (IPCs) of CS/HPMC were prepared and investigated by FT-IR. The mixtures of IPCs/BCP were heated up to 100 °C for analyzing their thermal expansion properties. This resulted in ~13% and ~42% volume increment for IPC-1/BCP and IPC-2/BCP, respectively, while ~230% volume increased in the case of IPC-3/BCP (therefore chosen for sintering bone blocks). Heating rate-dependent (0.20–0.25 °C/min range) sintering profiles for IPC-3/BCP were utilized to produce BCP bone blocks. Gasification of IPC during sintering resulted in the formation of interconnected porous structures, and the morphology was investigated by SEM, revealing varying sizes ranging from 106 ± 13 μm to 1123 ± 75 μm. The pore size range of bone blocks from 235 ± 46 μm to 459 ± 76 μm portrayed significantly high MC3T3-E1 cell viability with prominent filopodial extensions, and elongated cells, depicting efficient biocompatibility. Therefore, the process for preparing porous interconnected 3D bone blocks were feasible, thereby serving as an alternative for potential bone tissue engineering applications.

A modular solid-state pulse generator based on a multi-turn linear transformer driver (LTD) is designed for the application of pulse power techniques with a high voltage, large current and wide pulse width. The LTD adopts the method of multi-turn winding on the magnetic core, which can help to output pulses of wide width. The isolation of the power supply with windings in the same direction of the LTD modules is designed, and the isolation voltage of the magnetic cores is the working voltage of the LTD modules. A modular solid-state pulse generator based on the multi-turn LTD is developed, which is composed of 10 LTD modules. Each module consists of 18 energy storage capacitors, metal-oxide-semiconductor field-effect transistors and their driving circuits connected in parallel. The pulse generator can output pulses with parameters including a voltage ranging from 0 to 5000 V, a pulse current up to −500 A, and a pulse width ranging from 200 ns to 5 μs. When all modules work in synchronisation, rectangular pulses can be produced with a rise time of 30 ns and a fall time of 16 ns. If all modules are asynchronised, trapezoidal pulses are produced with adjustable step-like rising and falling edges. Moreover, a higher-voltage pulse can be achieved by increasing the number of LTD modules.

Herein, we aim to suggest a facile method for fabrication of Ni-based nanonetworks via templated electroless plating using mesoporous polymers as templates. With the control of spinodal decomposition for the polymer/crystalline solvent mixture, it is feasible to fabricate mesoporous polystyrene with controlled porosity and pore size as well as its distribution that could serve as a template for templated electroless plating. By taking advantage of the development of reduced Ni from the electroless plating, nanoporous Ni spheres with controlled micrometer-sized particle could be directly acquired, providing the feasibility as heterogeneous catalysts in aimed reactions. With the high specific surface area, the fabricated nanonetwork Ni gave rise to superior performance for catalytic hydrogenation of unsaturated organics and polymers. With the magnetic properties of Ni, catalyst recyclability could be simply achieved by magnetic field. This approach is simple and cost-effective to create nanoporous Ni spheres with high catalytic efficiency and well selectivity for hydrogenation performance.

The residual flux (RF) in three-phase transformers can dramatically increase the inrush current when the transformer is energized. The RF can also severely interfere with diagnostic tests, such as the frequency-response analysis (FRA) test. However, there is no effective method to fully eliminate the RF in the core of a three-phase transformer. Additionally, there are few relevant experimental reports on methods to accurately measure the RF in the magnetic core of a three-phase transformer; this measurement is important for evaluating the demagnetization results and phase-controlled switching strategies. Hence, this paper proposes an improved flux-controlled variable frequency-constant voltage (VFCV) strategy combined with core flux equalization to simultaneously eliminate and measure the RF of a three-phase transformer core by applying a low-power electronic device. The effectiveness and accuracy of the proposed strategy are validated by the simulation and experimental tests of a 10 kV distribution transformer and a 500 kV delta-connection three-phase separating transformer. The results reveal that the RF can be eliminated to less than 1% of the knee point flux and that the measurement is fairly accurate.

Perturbing the electronic structure of the MoS2 basal plane by confining heteroatoms offers the opportunity to trigger in-plane activity for the hydrogen evolution reaction (HER). The key challenge consists of inducing the optimum HER activity by controlling the type and distribution of confined atoms. A distance synergy of MoS2 -confined single-atom rhodium is presented, leading to an ultra-high HER activity at the in-plane S sites adjacent to the rhodium. By optimizing the distance between the confined Rh atoms, an ultra-low overpotential of 67 mV is achieved at a current density of 10 mA cm-2 in acidic solution. Experiments and first-principles calculations demonstrate a unique distance synergy between the confined rhodium atoms in tuning the reactivity of neighboring in-plane S atoms, which presents a volcanic trend with the inter-rhodium distance. This study provides a new strategy to tailor the activity of MoS2 surface via modulating the distance between confined single atoms.