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In this work, the solution plasma-assisted method was used to prepare NiMnAl-LDO (layered double oxides) catalysts with different treatment times, which were used for the CO2 methanation reaction. Solution plasma treatment can enhance the dispersibility of the catalyst, create oxygen defects and improve the chemical adsorption capacity of the catalyst. The results show that the low-temperature activity of the catalyst has been improved after the solution plasma treatment. We demonstrate that the NiMnAl-LDO-P(20) catalyst with high dispersion has the highest catalytic activity in CO2 methanation (81.3% CO2 conversion and 96.7% CH4 selectivity at 200 °C). Even though working for 70 h, the catalyst is still highly stable. This work provides a great promise for improving the low-temperature activity of Ni-based catalysts.

CO methanation has attracted much attention because it transforms CO in syngas and coke oven gas into CH4. Here, porous Al2O3 microspheres were successfully used as catalyst supports meanwhile the Mn was used as a promoter of Ni/Al2O3 catalysts. The as-obtained Ni/Al2O3 and Mn–Ni/Al2O3 samples display a micro-spherical morphology with a center diameter near 10 μm. Versus the Ni/Al2O3 catalyst, the 10Mn–Ni/Al2O3 catalyst exhibits a high specific surface area of 92.5 m2/g with an average pore size of 7.0 nm. The 10Mn–Ni/Al2O3 catalyst has the best performance along with can achieve a CO conversion of 100% and a CH4 selectivity of 90.7% at 300 °C. Even at 130 °C, the 10Mn–Ni/Al2O3 catalyst shows a CO conversion of 44.0% and a CH4 selectivity of 84.1%. The higher low-temperature catalytic activity may be since the catalyst surface contains more CO adsorption sites and thus has a stronger adsorption performance for CO. Density functional theory (DFT) calculations confirm that the Mn additive enhances the adsorption of CO, especially for the 10Mn–Ni/Al2O3 catalyst with the strongest adsorption energy.

Hollow-structured SiO2, which comprises a void space inside a distinct shell with its intriguing physicochemical properties and huge potential, has been widely applied in many methanation catalysts. However, the common methods for preparing SiO2 hollow microspheres are cumbersome and time consuming. Highly uniform hollow nanoflowers, silica (SiO2) nanospheres with different sizes, were synthesised through a rapid, time-saving method known as flash nanoprecipitation. An assembling particle mechanism of the hollow structure of Mo–polydopamine complex was established and tetraethyl orthosilicate underwent uniform hydrolysis on the surface of the hierarchical structure. Spherical SiO2 samples with different morphologies were prepared as catalyst carriers, and Ni-based methanation catalysts were prepared using an impregnation method. Ni particles with size of 3 nm were successfully attached to the surface of MoDo–H–SiO2, while the particle sizes of Ni on CTS–MoDo–H–SiO2 was 7 nm. The small particles (3 nm) were found to significantly increase in size (20–50 nm), decrease by 90% in stability test with a weight hourly space velocity (WHSV) of 26,000 mL.g−1.h−1, which is detrimental to catalyst stability. However, the medium sized particles (7 nm) remained confined via a suitable interaction involving the support, thus displaying enhanced stability, with 100% CO conversion at 250 °C and no obviously decrease in stability test Although more active sites can be provided with smaller active metals, catalysts with small sized particles deactivate faster and to a larger extent than catalysts with medium sized particles. Thus, the smaller the particle size of the active component, the worse the stability.

Owing to the advantages of high efficiency, high energy density, electrical isolation, low electromagnetic interference (EMI) and harmonic pollution, magnetic integration, wide output ranges, low voltage stress, and high operation frequency, the LLC resonant converters are widely used in various sectors of the electronics-based industries. The history and development of the LLC resonant converters are presented, their advantages are analyzed, three of the most popular LLC resonant converter topologies with detailed assessments of their strengths and drawbacks are elaborated. Furthermore, an important piece of research on the industrial applications of the LLC resonant converters is conducted, mainly including electric vehicle (EV) charging, photovoltaic systems, and light emitting diode (LED) lighting drivers and liquid crystal display (LCD) TV power supplies. Finally, the future evolution of the LLC resonant converter technology is discussed.

An ultra-high frame rate and high spatial resolution ion-sensing Lab-on-Chip platform using a 128 × 128 CMOS ISFET array is presented. Current mode operation is employed to facilitate high-speed operation, with the ISFET sensors biased in the triode region to provide a linear response. Sensing pixels include a reset switch to allow in-pixel calibration for non-idealities such as offset, trapped charge and drift by periodically resetting the floating gate of the ISFET sensor. Current mode row-parallel signal processing is applied throughout the readout pipeline including auto-zeroing circuits for the removal of fixed pattern noise. The 128 readout signals are multiplexed to eight high-sample-rate on-chip current mode ADCs followed by an off-chip PCIe-based readout system on a FPGA with a latency of 0.15 s. Designed in a 0.35 $\,\boldsymbol {\mu}$ m CMOS process, the complete system-on-chip occupies an area of 2.6 × 2.2 $\text{mm}^2$ with a pixel size of 18 × 12.5 $\,\boldsymbol {\mu}$ $\text{m}^2$ and the whole system achieves a frame rate of 3000 fps which is the highest reported in the literature for ISFET arrays. The platform is demonstrated in the application of real-time ion-imaging through the high-speed visualization of sodium hydroxide (NaOH) diffusion in water at 60 fps on screen in addition to slow-motion playback of ion-dynamics recorded at 3000 fps.

In this paper, a Lab-on-Chip platform with ultra-high throughput and real-time image compression for high speed ion imaging is presented. The sensing front-end comprises of a CMOS ISFET array with sensors biased in velocity saturation for a linear pH-to-current conversion and high spatial and temporal resolution. An array of 128 × 128 pixels is designed with a pixel size of 13.5 $\boldsymbol{\mu}$ m × 10.5 $\boldsymbol{\mu}$ m. In-pixel reset switches are applied for offset compensation, by asynchronously resetting the floating gate of the ISFET to a known fixed potential. Additionally, each row of pixels is processed by a current mode signal pipeline with auto zeroing functionality to remove fixed pattern noise, followed by an on-chip 1 MS/s 8-bit row-parallel single slope ADC. Fabricated in standard TSMC 180 nm BCD process, the entire system-on-chip occupies a silicon area of 2 mm × 2 mm, and achieves a frame rate of 6100 fps (7800 fps from simulation). A high speed 25 ms-latency readout platform based on a USB 3.0 interface and standard JPEG is presented for real-time ion imaging and image compression respectively, while an optimised JPEG algorithm is also designed and verified for a higher compression ratio without sacrificing image quality. We demonstrate real-time ion image visualisation by sensing high speed ion diffusion at 6100 fps, which is more than two times faster than the current state-of-the-art.

This paper presents and analyzes an AC-DC power converter structure, which is comprised of a Power Factor Correction (PFC) module and a LLC resonant DC-DC converter module. This converter only uses two switches, and requires three less diodes and one less switch compared to popular LLC resonant converter solutions. Compared to its conventional counterpart, the rectifier of interest has high energy efficiency while a smaller size, owing to the soft-switching in the LLC resonant converter. Detailed theoretical analyses are conducted in this study, followed by software simulation and hardware experimentation, which demonstrate that the single stage double-switched (DS)-LLC rectifier is able to realize unity power factor and a wide output range, indicating its effectiveness and applicability.

When acrylic acid (AA) is synthesized from acetylene carbonylation using supported nickel as a heterogeneous catalyst, it is important to select a suitable carrier material. Accordingly, we prepared a series of nickel-loaded catalysts using treated expanded two-dimensional layered vermiculite (2D-VT), NaY, HY, MCM-41, and talcum powder (TP) as carriers. As a result, it was found that the calcined nickel-supported expanded NiO/2D-VT exhibited excellent catalytic performance as a catalyst. The highest yield (83.1%) was obtained. We used XRD, SEM, TEM, BET, FTIR, TGA, ICP and XPS to thoroughly characterize the catalysts. It was found that the two-dimensional layered structure of vermiculite (VT) itself with a hydroxyl structure provides a loading site for the active metal NiO, which promotes the formation of a hydrogen carboxyl group. And the excellent thermal stability of VT inhibits the formation of carbon deposits in the NiO/2D-VT catalyst during the reaction. Compared with other catalysts, the NiO/2D-VT catalyst has significantly less carbon deposits, more cycles are used, and activity decreases more slowly. In addition, we also studied the reasons for the decrease in the activity of the NiO/2D-VT catalyst used repeatedly, and found that the loss of NiO supported on the VT two-dimensional layered structure is the main reason for the catalyst deactivation.

Sustainable development is a worldwide concern. This work mainly focuses on the reuse of the combustion products of calcium carbide and the influence of different kinds of copper on the acetylene carbonylation reaction. A series of catalysts were prepared by heating the precursors under various atmospheres (air, hydrogen, and nitrogen). The X-ray diffraction and the X-ray photoelectron spectroscopy have been analyzed regarding copper species composition and content in catalysts. The result of the Cu+-promoted reaction was in good agreement with the conducted density functional theory analysis, and we speculate that Cu+ promotes the transfer of electrons in the reaction. Transmission electron microscopy and elemental mapping evaluation confirmed the difference in Cu dispersion. Characterization of catalysts using temperature programmed desorption and pyridine Fourier-transform infrared revealed differences in their acidity. Acidity was found to be favorable for acetylene carbonylation. Selectivity and yield of the CuAlZn-LDO(N) catalyst at 225 °C were 73 and 70%, respectively, and the catalyst showed good stability over two consecutive cycles of reuse.

Low-temperature performance of non-noble metal Ni-based catalysts in CO2 methanation still faces great challenges. A series of NiMnAl-LDO (layered double oxides) catalysts with different processing conditions were prepared using the high-shear mixer-assisted method. The FH-C (80 °C) catalyst exhibited high activity in low-temperature CO2 methanation, and CO2 conversion and CH4 selectivity reached 85% and 97% at 200 °C. Characterization results show that the strong shear force of the high-shear mixer can improve the dispersion of the catalyst and reduce the particle size of the catalyst. The high-shear mixer treatment increases the CO2 chemisorption and the number of strongly basic sites on the catalyst. The main reason for the low-temperature activity of the catalyst is that the high-shear mixer increases the number of oxygen vacancies in the catalyst. In situ infrared probes into the surface species and intermediate products of the catalyst, confirming that formate is an intermediate product of the CO2 methanation reaction. Density functional theory calculations demonstrated that increasing the content of oxygen vacancies is beneficial for increasing the CO2 adsorption capacity of the catalyst and reducing the reaction energy barrier of CO2 → COOH*.

This article develops an advanced self-protected single-stage ac-dc LLC resonant converter, in which one diode is introduced to realize overvoltage prevention to achieve self-protection, lower costs, and smaller size. Besides, the proposed converter can also realize power factor correction (PFC), soft switching, and a wide output voltage range, which meets the needs of many applications, such as liquid crystal display (LCD) TV power supply. Detailed analyses are presented to well demonstrate the features of the proposed converter, including the PFC and zero voltage switching turn-on functions. Thereafter, closed-loop control and parameter matching design are conducted in this study. Lastly, prototype experimentation of 220-V ac, 200 W verifies the effectiveness of the proposed converter design. This work was supported by the National Natural Science Foundation of China under Grant 51907032, in part by the Natural Science Foundation of Guangdong Province under Grant 2017B030312001 and Grant 2018A030313365, in part by the Guangdong Basic and Applied Basic Research Foundation under Grant 2020A1515010763, and in part by the Science and Technology Planning Project of Guangzhou under Grant 201804010310.

Ni/Al2O3 spherical catalysts were prepared by high shear mixer (HSM)-assisted coprecipitation (CP) and spray drying (SD) method for carbon monoxide (CO) and carbon dioxide (CO2) methanation. The effect of HSM technology on low-temperature methanation performance was studied. Ni/Al2O3 (HSM-CP-SD) catalysts provide excellent performance such as CO conversion of 100% and CH4 selectivity of 90% at 300 °C; the CO2 conversion was 86.2% and CH4 selectivity was 95.3% at 350 °C. Even at 200 °C, the catalyst prepared by HSM still offers a CO conversion of 90% and CH4 selectivity of 82%, whereas the Ni/Al2O3 (CP-SD) has no activity. The high performance was attributed to the small Ni nanoparticles and high dispersion. The Ni/Al2O3 (HSM-CP-SD) catalysts exhibit micro-spherical morphology with a big pore size of 3.46 nm, stronger metal-support interactions, and CO adsorption capacity. The catalyst prepared by HSM shows potential application for CO/CO2 methanation, and HSM technology can optimize other heterogeneous catalytic reactions.

This paper presents a 128 × 128 ISFET array with current mode readout peripherals for real-time ion imaging. Current-mode operation is employed to achieve very high speed and frame rate and provide a linear mapping between the ion concentration at the sensing layer (typically hydrogen ions — pH) to the drain current of the device. To this effect, a single device biased in the triode region can serve as both the sensing and readout device in the pixel ensuring a very small area footprint per pixel. Compensating for known non-ideal effects of the ISFET, namely trapped charge and drift, is implemented by resetting the gate voltage whereas any additional circuit offsets are eliminated by auto-zeroing. Auto-zeroing and sampling takes place on a row-parallel basis which is then multiplexed to 8 current mode ADCs. The chip is designed in a standard 0.35um CMOS process, occupies an area of 2.6mm × 2.2mm and can achieve a frame rate of 3000 fps which is the highest in this process node. We anticipate that the proposed system will increase the current temporal limit of detection of chemical reactions and provide new insight into real-time ion dynamics.

In this paper, we introduce a modular framework to detect noisy logo appearing on online merchandise images so as to support the forensics investigation and detection of increasing online counterfeit product trading and fraud cases. The proposed framework and system is able to perform an automatic logo image classification on realistic and noisy product images. The novel contributions in this work include the design of a modular SVM-based logo classification framework, and its internal segmentation module, two new feature extractions modules, and the decision algorithm for noisy logo detection. We developed the system to perform an automated multi-class product images classification, which achieves promising results on logo classification experiments of Louis Vuitton, Chanel and Polo Ralph Lauren.