Removal of the CO2 impurities from C2H2/CO2 mixtures is an essential process to produce high-purity C2H2. Fabricating an adsorbent capable of discriminating these species, which have close kinetic ...diameters, is critical for developing advanced adsorption processes. Herein, we demonstrate a strategy to exploit the tunability of interlayer and intralayer spaces of two-dimensional (2D) layered metal–organic frameworks to achieve high performance for C2H2/CO2 separation. This indicates that interlayer symmetrical control can achieve more efficient packing of C2H2 into Ni(4-DPDS)2CrO4, with a high C2H2 capacity of 45.7 cm3·g–1 at 0.01 bar and a selectivity of 67.7 (298 K, 1 bar), which strikes a good balance between working capacity and separation selectivity compared to other isostructural Ni(4-DPDS)2MO4 (M = Mo, W). Crystallographic studies and DFT-D calculations reveal that such a C2H2-selective adsorbent possesses strong binding interactions due to the tailored pore confinement provided by the angular anions and rich electronic environment. Experimental breakthrough results comprehensively demonstrate the efficient C2H2/CO2 separation performance of this unique material.
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IJS, KILJ, NUK, PNG, UL, UM
The separation of structurally similar compounds, such as cholic acid (CA) and deoxycholic acid (DCA), is challenging due to their nearly identical physicochemical properties. This study demonstrates ...a synergistic 'push and pull' strategy with an ionic liquid (IL) biphasic system for significantly enhanced CA/DCA separation efficiency. Ethyl acetate was selected as the feed solvent to 'push' CA into the IL-rich extractant phase, while the IL 1-ethyl-3-methylimidazolium chloride (EMIMCl) was chosen to 'pull' CA due to their strong hydrogen bonding interaction. This 'push and pull' system yielded a remarkable CA/DCA selectivity up to 47.8, much higher than the case using
n
-butanol which pulls both CA and DCA. The underlying separation mechanism was elucidated through computational screening with COSMO-RS, NMR analysis, and solvatochromic measurements. Results revealed the critical roles of specific hydrogen bonding between the chloride anion of EMIMCl and the hydroxyl/carboxyl groups of CA/DCA, along with nonspecific interactions between the feed solvent and CA/DCA. Thermodynamic analysis of the phase transfer process confirmed the 'push and pull' synergy is energetically favorable for preferentially transferring CA from the ethyl acetate feed solution into the IL-rich extractant phase. Multi-stage simulation indicated that 99% purity and recovery of both CA and DCA can be obtained through this biphasic system under optimized conditions. Overall, strategically tuning both the feed solvent and IL extractant could significantly enhance the separation efficiency of structurally similar compounds while minimizing solvent and energy consumption. This 'push and pull' approach may shed light on improving separation processes for other structural analogues.
A 'push and pull' strategy is applied to enhance the liquid-liquid extraction separation efficiency of cholic acid (CA) and deoxycholic acid (DCA) based on ionic liquid (IL).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
5.
Active Harmonic Suppression in a Series 12-Pulse Rectifier Shuanglian, Yang; Damin, Zhang; Zhiyong, Lin ...
2022 IEEE International Power Electronics and Application Conference and Exposition (PEAC),
2022-Nov.-4
Conference Proceeding
Traditional DC-side active harmonic method has the problems of complex circuit structure and great power losses. This paper suggests an active harmonic suppression technique on the DC side to enhance ...the harmonic suppression capabilities of the input side of the series 12-pulse rectifier. This method uses an inverter circuit with a center-tapped transformer to generate a square wave voltage and inject it into the DC side, adjust the output current of the rectifier, and then adjust the rectifier's input current so that it closely resembles a sine wave based on the relationships between the DC side's injection voltage and the AC side's current flow. The analysis and simulation structure show that when the load changes, the grid-side current's overall harmonic distortion rate is below 3.5%, and this strategy can effectively suppress the harmonics of the rectifier input current.
Large grid impedance is the main characteristic of weak grid, and its accurate detection can improve the inverter control performance. However, traditional impedance detection method based on current ...harmonic injection usually causes a large increase in harmonics, which weakens the power quality. In order to solve this problem, an improved multiple harmonic injection method based on QPR (Quasi Proportional Resonance) parameter-adaptive control strategy is proposed in this paper. By analyzing the impedance detection results and the power quality of the inverter output, the impedance detection results are sent to the adaptive control system, which is used to correct the quality of the grid-connected current waveform after calculating each parameter of the QPR controller. The final simulation results show that the proposed improved control strategy can improve the inverter output waveform quality and enhance the anti-interference capability of the weak grid without changing the impedance detection accuracy of the wind power grid-connected inverter under weak power conditions.
In order to improve the harmonic suppression ability of 12-pulse controlled rectifier, a DC-side harmonic suppression scheme based on predictive current control strategy is studied. The control ...strategy improves the input current waveform of the rectifier by adding a boost converter circuit on the DC-side to meet the requirements of input current harmonic suppression under different load conditions. According to the current relationship between AC and DC sides of 12-pulse rectifier and the ideal current waveform at DC side, this paper analyzes and gives the input current waveform of boost converter circuit, and uses PWM method to adjust the input current of boost converter. Simulation results show that this method can effectively suppress the input current harmonics of 12-pulse controlled rectifier.
Herein, we propose a lateral flow immunoassay (LFIA) based on the dual spectral-overlapped fluorescence quenching of polydopamine nanospheres (PDANs) caused by the inner filter effect to sensitively ...detect sulfamethazine (SMZ). The fluorescence quenching LFIA device consists of four parts: absorbent pad, polyvinyl chloride pad, sample pad, and nitrocellulose membrane. Compared with traditional quenchers such as gold nanoparticles (AuNPs) with single spectral-overlapped quenching ability, PDANs can quench the excitation light and emission light of three fluorescence donors (aggregation-induced emission fluorescent microsphere, AIEFM; fluorescent microsphere, FM; and quantum dot bead, QB). The fluorescence intensity changes (ΔF) are numerically larger for PDANs-LFIA (ΔFAIEFM = 2315, ΔFFM = 979, ΔFQB = 910) than those for AuNPs-LFIA (ΔFAIEFM = 1722, ΔFFM = 833, ΔFQB =;520). AIEFM-based PDANs-LFIA exhibits a large ΔF (2315) in response to the changes in the SMZ concentration, and produces a high signal-to-noise ratio. The limit of detection (LOD) and visual LOD of LFIA based on PDANs quenching AIEFM for the detection of SMZ in chicken are 0.043 and 0.5 ng/mL, respectively. The results confirm that the proposed method can be used for the detection of hazardous materials in practical applications.
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•LFIA based on dual spectral-overlapped fluorescence quenching of PDANs was developed.•PDANs can quench the excitation light and emission light of fluorescence donor.•The detection performance of LFIA can be improved using PDANs as the quencher.•The proposed LFIA can simultaneously provide triple mode signal output.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper focuses on the non-convex joint optimization with a dynamic resource of multi-user for an intelligent reflecting surface-enhanced mmWave system, where all users have individual rates or ...quality of service requirements. Firstly, the objective function of the above non-linear problem is converted into a quadratic programming form under the quality of service constraints. Further, a multi-blocks alternating optimization framework with dynamic power allocation is proposed to obtain the maximum sum-rate, where the relaxed ADMM algorithm is adopted to tackle the optimal full-digital precoder and the corresponding passive reflecting matrix is obtained by the gradient-projection. The numerical results verify that beam optimization should be emphasized in high SNR, but joint dynamic resource allocation can further improve system performance even if the hardware dimensions reaches the limit.
This paper considers the hybrid precoding design with quantized phase shifters (PSs) for full-duplex millimeter-wave relaying systems, in which the relay node is equipped with PSs of different ...resolution levels. The joint optimization of relay hybrid precoding and discrete PSs is a high-dimensional non-convex problem with both higher-order polynomial and modulus constraints. To solve this challenging problem, the optimization function under the imperfect channel state information (CSI) is reformulated into a low-complexity norm-minimization form equation. Then, a relaxed algorithm based on the alternating direction method of multipliers and quantization steps is proposed to obtain the coupling approximate solutions for the above optimized equation. And the optimality of analytical solutions is guaranteed based on the imposed termination criterion and necessary conditions. Furthermore, given the requirement of arbitrary quantization, the trade-off between spectral efficiency (SE) and energy efficiency (EE) is investigated under the imperfect CSI. Numerical results verify that the hybrid precoding with low-resolution PSs can achieve excellent SE close to the full-resolution one but with a considerably lighter burden of energy consumption. Moreover, the transmission power plays a positive role in compensating quantization loss, but the excessive value will bring the reduction of EE.
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