- 标题
- 摘要
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- 实验方案
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Monometallic Catalytic Models Hosted in Stable Metal-Organic Frameworks for Tunable CO2 Photoreduction
摘要： The photocatalytic reduction of CO2 to energy carriers has emerged as one of the most promising strategy to alleviate the energy crisis and CO2 pollution, for which the development of catalyst was considered as the determining factor for the accomplishment of this conversion process. In this study, three stably and isostructural metal organic frameworks (denoted as MOF-Ni, MOF-Co and MOF-Cu), have been synthesized and used as heterogeneous catalysts applied into photocatalytic CO2 reduction reaction (CO2RR). It is worth noting that the MOF-Ni exhibited a very high selectivity of 97.7% for photoreducing CO2 to CO, which has exceeded most of the reported MOF-based catalysts in the field. Significantly, the MOFs associated with monometallic catalytic centre offer a simply and precisely structural model which allows us to understand the specific effects of different metal ion species on photoreduction of CO2 as well as reactive mechanism more intuitively.
关键词： Isostructural,Metal-Organic Frameworks,Photocatalytic CO2 Reduction,High Selectivity,Monometallic Catalytic Model,Reactive Mechanism
更新于2025-09-23 15:22:29
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A rhodamine-deoxylactam based fluorescent probe for fast and selective detection of nitric oxide in living cells
摘要： Nitric oxide (NO) plays vital roles in many physiological process and is closely related to many diseases. So far, a number of fluorescent probes have been constructed for the detection of NO successfully. However, the probes still suffer from long-time reaction and limited selectivity. Herein, a fluorescent probe named dRB-OPD is synthesized and used to recognize NO. The probe contains a deoxy-rhodamine B as fluorophore and o-phenylenediamino as reaction site. dRB-OPD shows fast response to NO within 40 seconds with 170-fold fluorescence enhancement. Moreover, the probe shows high selectivity towards NO over dehydroascorbic acid (DHA), ascorbic acid (AA), and methylglyoxal (MGO). Particularly, the probe can avoid the serious interference from cysteine (Cys) found in the rhodamine lactam-based fluorescent NO probes (RB-OPD). In addition, the probe is applied for the detection of exogenous and endogenous NO in the HepG2 and RAW 264.7 cells with satisfactory results.
关键词： Cell imaging,Fluorescent probe,Nitric oxide,High selectivity,Fast response
更新于2025-09-23 15:22:29
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[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A Waveguide Bandpass Filter with High Selectivity Using Slot Excitation
摘要： Under the excitation of a pair of shifted inclined slots, TE101, TE011 and TM110 modes in a single rectangular cavity are excited, and exploited to form a passband of bandpass filter (BPF). The pair of slots are fed through microstrip lines at the input and output port. Based on the single triple-mode rectangular cavity, a dual-cavity BPF is designed, fabricated and measured to enhance the selectivity of filter by cascading two single ones. The BPF could achieve about 32 MHz bandwidth at center frequency of 2.98 GHz, and two transmission zeros (TZs) at 2.925 and 3.005 GHz, leading to the suppression outside passband larger than 50 dB in the vicinity of center frequency.
关键词： Waveguide,Slot Excitation,High Selectivity,Bandpass Filter
更新于2025-09-23 15:19:57
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<scp>Coupleda??line</scp> banda??pass filter with <scp>Ta??shaped</scp> structure for high frequency selectivity and stopband rejection
摘要： A coupled-line band-pass filter (BPF) with T-shaped stub structure is presented. Five transmission poles within the passband and eight deep transmission zeros (TZs) from 0 to 2f0 (f0 denotes filter's center frequency) are realized through input impedance calculations. With the simple T-shaped structure, the positions of six TZs can be appropriately adjusted to achieve high frequency selectivity and stopband rejection. For demonstration, a BPF prototype centered at 2.05 GHz is designed and fabricated, whose measured rejection levels are of over 45.5 dB at lower stopband and better than 19.5 dB at upper stopband. The simulation and measurement results are in good agreement, which validates the design idea.
关键词： high selectivity,band-pass filter,T-shaped structure,stopband rejection,coupled-line
更新于2025-09-23 15:19:57
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COMPACT SINGLE-LAYER BALANCED EIGHTH-MODE SUBSTRATE INTEGRATED WAVEGUIDE BANDPASS FILTER WITH HIGH SELECTIVITY
摘要： This letter proposes a compact single-layer balanced bandpass ?lter (BPF), which is realized by a new arrangement of eighth-mode substrate integrated waveguide (EMSIW) cavities. Under di?erential-mode (DM) operation, the half bisection topology of the proposed EMSIW ?lter can be equivalent to a quadruplet scheme based on four coupled EMSIW cavities. The negative cross coupling can be easily realized by the nature of the fringe electric ?elds of opened ends of EMSIW cavities. For the demonstration, a balanced EMSIW ?lter with the operating frequency at 2.4 GHz is designed, fabricated, and measured.
关键词： eighth-mode substrate integrated waveguide,compact size,high selectivity,balanced bandpass filter
更新于2025-09-19 17:13:59
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[IEEE 2019 International Conference on Electromagnetics in Advanced Applications (ICEAA) - Granada, Spain (2019.9.9-2019.9.13)] 2019 International Conference on Electromagnetics in Advanced Applications (ICEAA) - 3-D dual-band FSSs based on multiple square coaxial waveguides
摘要： In this paper, a kind of dual-band three-dimensional (3-D) frequency selective surfaces (FSSs) based on multiple square coaxial waveguides (SCWs) are proposed. Through a simple design, transmission poles are intrinsically produced by the square slot resonances in two SCW propagation paths, and another transmission pole is generated by a parallel-plate waveguide (PPW) propagation path. With the help of these three transmission poles, a closely-spaced dual-band 3-D FSS can be achieved with the band ratio 1.118. In order to further extend the application of the proposed structure, a modified design is then exhibited. One pair of short SCW resonant elements is created in each SCW propagation path. As a result, each SCW propagation path can provide two transmission poles for a flat passband by the odd- and even-mode coupling. Moreover, the transmission zeros are located at each sides of passbands, leading to both-sided sharp roll off. The unit cell size of the modified design is reduced remarkably. The E-field analysis of transmission zeros/poles is given to explain the operating principle of two proposed FSSs. The simulated results show that the proposed FSSs can achieve stable responses to variations of incident angle from 0° to 45° for both TE and TM polarizations.
关键词： frequency selective surface (FSS),band ratio,dual-band,high selectivity,square coaxial waveguides (SCWs)
更新于2025-09-19 17:13:59
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Compact three-dimensional bandpass FSS with high selectivity based on split square coaxial waveguide
摘要： In this Letter, a compact three-dimensional (3D) frequency selective surface (FSS), exhibiting a bandpass filtering response with high selectivity, is proposed based on the split square coaxial waveguide (SSCW). The unit cell of the presented 3D FSS consists of one parallel-plate waveguide propagation path and one SSCW propagation path. In the SSCW path, two identical short SCWs are produced by employing a centred annular slot. Each short SCW intrinsically provides a square slot resonance. Owing to the electromagnetic coupling between these two square slot resonances, original single square slot resonant mode will split into even-/odd-resonant modes, resulting in a flat passband with two transmission poles. Moreover, two transmission zeros located at both sides of the passband are introduced for high selectivity, because the electromagnetic waves passing through these two different paths are combined out of phase. By investigating the electric-field distributions at the frequencies of the transmission zeros/poles, the operating principle of the proposed 3D FSS is described. A prototype of the proposed 3D FSS is fabricated and measured. The measured results show that the proposed design can achieve a stable response under the incident angles up to 60° for both TE and TM polarisations.
关键词： frequency selective surfaces,bandpass filtering,compact,split square coaxial waveguide,high selectivity
更新于2025-09-16 10:30:52
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Substrate‐integrated waveguide filtering crossovers with improved selectivity
摘要： Two substrate-integrated waveguide (SIW) filtering crossovers with high selectivity are presented. The orthogonal degenerate TE201 and TE102 modes in center square cavity are employed to realize the cross transmission and channel isolation. The offset coupling positions are then exploited for surrounding TE101-mode rectangular cavities to produce transmission zeros (TZs) above the passband in the first crossover design or for TE201-mode oversized rectangular cavities to generate one TZ on each side of the passband in the second crossover design. The footprint of first crossover has greatly been reduced, while the selectivity of both crossovers has been greatly improved. Two prototypes centered at 20 GHz are designed, fabricated, and tested for demonstration, showing good agreement between the simulated and measured results.
关键词： filtering crossovers,orthogonal degenerate modes,substrate-integrated waveguide,high selectivity
更新于2025-09-12 10:27:22
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Nitric Oxide Detector Based on WO <sub/>3</sub> -1wt%In <sub/>2</sub> O <sub/>3</sub> -1wt%Nb <sub/>2</sub> O <sub/>5</sub> with State-of-the-Art Selectivity and ppb-Level Sensitivity
摘要： Fast, sensitive, and precise detection of nitric oxide (NO) is critical to many applications in environmental monitoring and early disease diagnosis via respiratory testing. An effective detection system requires a sensor to detect NO gas at the parts per billion (ppb) level, and this system should possess a high degree of anti-interference selectivity. To achieve these targets, a series of gas sensor thin films based on intrinsic WO3, one-additive-doped WO3 (prepared by doping In2O3 or Nb2O5), and two-additive-doped WO3 (synthesized by doping with In2O3 and Nb2O5) oxides were successfully grown. By analyzing the properties of sensitivity, selectivity, responsiveness, and recovery time of the gas sensors, we found that WO3-1wt%In2O3-1wt%Nb2O5 has overwhelming advantages over intrinsic WO3, WO3-In2O3, and WO3-Nb2O5. A sensing response value of 2.4 was observed for NO concentrations as low as 20 ppb from the WO3-1wt%In2O3-1wt%Nb2O5 sensor. With 100 ppb NO gas, the WO3-1wt%In2O3-1wt%Nb2O5 sensor achieved a high response of 56.1 at 70 °C, which is a state-of-the-art performance for NO detection at low working temperature settings. WO3-1wt%In2O3-1wt%Nb2O5 also yields significantly improved selectivity and stability over intrinsic WO3, WO3-In2O3, and WO3-Nb2O5. Studies on the sensing mechanism show that the grain size, rather than the n?n heterostructure effect, plays a dominant role in the observed results. By decreasing the grain size so that it is close to the thickness of the space-charge layer, the sensing response is enhanced. Although room remains to further improve the sensing properties, the performance of WO3-1wt%In2O3-1wt%Nb2O5 is sufficient for implementation in low-content NO detection devices.
关键词： codoping,high selectivity,NO gas sensor,limit of detection (LOD),ppb-level response,pulsed laser deposition (PLD)
更新于2025-09-09 09:28:46
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A MINIATURIZED BANDPASS FREQUENCY SELECTIVE SURFACE WITH HIGH SELECTIVITY BASE ON SLOT COUPLING
摘要： A Ku-band bandpass frequency selective surface (FSS) with high selectivity and miniaturization is proposed in this paper. We use two metallic strips and one slot to design the frequency selective surface structure which contains both electrical and magnetic couplings. A metallic via is introduced in the FSS element for miniaturization. With the via inserted at the end of the metallic strip, the FSS unit size is reduced to half compared to that without via inserted. To investigate the operating principle of the slot-coupled FSS, an equivalent-circuit model is given and analysed using the odd- and even-mode method. The constructed out-of-phase signal path causes two transmission zeros (TZs) near the skirts of the narrow pass band, thereby enhancing the selectivity. A prototype of the proposed FSS operating at 16 GHz is fabricated and measured. The measured results agree well with the full-wave and circuit simulation results, thus verifying the FSS design.
关键词： slot coupling,Ku-band,bandpass frequency selective surface,metallic via,high selectivity,equivalent-circuit model,transmission zeros,miniaturization
更新于2025-09-09 09:28:46