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2D-Porphrinic Covalent Organic Framework-Based Aptasensor with Enhanced Photoelectrochemical Response for the Detection of C-Reactive Protein
摘要： In this study, a novel photoelectrochemical (PEC) aptasensor based on two-dimensional (2D) porphyrinic covalent organic frameworks (p-COFs) for the label-free detection of C-reactive protein (CRP) is presented. The obtained p-COFs possess high conductivity and an improved stability due to strong and rigid covalent linkages. The introduction of p-COFs hinder the recombination of electrons and holes, decreasing their band gap (Eg), thereby which improved the photocurrent conversion efficiency. Compared with pure porphyrin, p-COFs exhibited enhanced photocurrent intensity. An amplified photocurrent conversion efficiency and enhanced photocurrent results from H2O2, which act as active molecules and electron donors. As an unprecedented application of COFs in PEC bioanalysis, the detection of CRP with a PEC aptasensor is presented. The assembly of a CRP aptamer on the surface of Ag nanoparticles hinders the electron transfer, resulting in the decrease of the photocurrent response. This PEC aptasensor exhibits good analytical performances such as a rapid response, high stability, wide linear range and excellent selectivity, making COFs promising candidates for PEC bioanalysis.
关键词： C-reactive protein,Porphyrinic covalent organic framework,High photocurrent conversion efficiency,Photoelectrochemical aptasensor,Enhanced photocurrent
更新于2025-09-23 15:22:29
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Effective detective quantum efficiency of two detectors in a prototype digital breast tomosynthesis
摘要： Digital breast tomosynthesis (DBT) system is a novel imaging modality that strongly depends on the detector performance. The effective detective quantum efficiency (eDQE) is a newly accepted system of performance analysis metric that solves the disadvantages of conventional DQE evaluations, which do not consider clinical operating conditions. To evaluate the eDQE, we used the direct-conversion based Anrad detector and the indirect-conversion based Dexela detector. Our aim is to study the performance of such detectors when they are mounted on a prototype DBT system. The prototype DBT system consists of a CsI(Tl) scintillator/CMOS-based flat panel digital detector and an a-Se based direct conversion detector developed by the Korea Electrotechnology Research Institute (KERI). The performance of the two detectors was compared on the basis of scatter fraction, transmission factor, effective modulation transfer function (eMTF), and effective normalized noise power spectrum (eNNPS). As a result, the Dexela detector is characterized by a decreasing eNNPS trend as the spatial frequency increases, whereas the Anrad eNNPS looks almost independent of the spatial frequency. The eMTF was found to be higher in the Anrad detector compared to that in the Dexela one for all frequencies. The eDQE values at 1 cycle/mm (low frequency) were 0.11 and 0.17 for the Anrad and Dexela detectors, respectively, and the values of the spatial frequency feDQE (0.1), corresponding to eDQE = 0.1, were 1.25 and 2.81 cycles/mm for the Anrad and Dexela detectors, respectively. The Dexela detector also presented a higher contrast-to-noise ratios (CNRs) for all different sizes of μCa groups, thus demonstrating overall better eDQE results in imaging performance compared to the Anrad detector.
关键词： Direct/indirect conversion detectors,Effective detective quantum efficiency,Digital breast tomosynthesis
更新于2025-09-23 15:22:29
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High concentration Eu3+-doped NaYb(MoO4)2 multifunctional material: Thermometer and plant growth lamp matching phytochrome PR
摘要： Phytochromes PR and PFR are distributed in various organs of plant, phytochrome PR absorbs red light and phytochrome PFR absorbs far-red light, respectively, so the flower induction, etc. can be controlled by changing the ratio of red light to far-red light. The emission of Eu3+ (transition from 5D0/7F2) is located at the red range and matches with the absorption band of PR. Herein, we synthesized successfully NaYb(MoO4)2: Eu3+ phosphors with the high doping concentration (50%) by hydrothermal method with further calcinations. The LED device was also fabricated by the blue InGaN chip combined with the red phosphors NaYb(MoO4)2: 50%Eu3+ based on the excellent luminescent intensity. Moreover, the effect of temperature on the excitation intensity ratio of MoO4 2- to Eu3+ has also been studied, which provided the possibility of simultaneous luminescence and temperature measurement. This work is the first time to use Eu3+ as a red source matching PR, and the red phosphors have potential value to control plant growth.
关键词： Down-conversion luminescence,Temperature sensing,LEDs,Plant cultivation,Red phosphors
更新于2025-09-23 15:22:29
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Up-conversion characteristic and Judd-Ofelt calculation of BaGd2ZnO5:Er3+/Yb3+ microcrystalline powder
摘要： Er3+/Yb3+ co-doped BaGd2ZnO5 microcrystalline powder are prepared through high-temperature solid phase method. Absorption spectrum are obtained and spectral characteristic are analyzed through Judd-Ofelt theory. The calculated spectrum intensity parameters are Ω2 = 3.01 × 10?20 cm2, Ω4 = 3.76 × 10?20 cm2 and Ω6 = 0.43 × 10?20 cm2, respectively. The transition probability, branching ratio and energy level lifetime of Er3+ ion in BaGd2ZnO5 microcrystalline host are calculated. Up-conversion spectrum under 980 nm excitation are measured, The analyzed results indicates that three peaks of up-conversion luminescence, located at 533 nm, 553 nm and 670 nm, all belong to two photon absorbing process.
关键词： Judd-ofelt theory,BaGd2ZnO5,Up-conversion luminescence
更新于2025-09-23 15:22:29
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3D Yolk@Shell TiO2-x/LDH Architecture: Tailored Structure for Visible Light CO2 Conversion
摘要： CO2 photo-conversion into hydrocarbon solar fuels by engineered semiconductors is considered as a feasible plan to address global energy requirements in times of global warming. In this regard, three dimensional yolk@shell hydrogenated TiO2/Co-Al layered double hydroxide (3D Y@S TiO2-x/LDH) architecture was successfully assembled by sequential solvothermal, hydrogen treatment and hydrothermal preparation steps. This architecture revealed a high efficiency for the photo-reduction of CO2 to solar fuels, without a noble metal co-catalyst. The time dependent experiment indicated that the production of CH3OH was almost selective until 2h (up to 251 μmol/gcat. h.), whereas the CH4 was produced gradually by increasing the time of reaction to 12h (up to 63 μmol/gcat. h.). This significant efficiency can be ascribed to the engineering of 3D Y@S TiO2-x/LDH architecture with considerable CO2 sorption ability in mesoporous yolk@shell structure, and LDH interlayer spaces. Also, oxygen vacancies in TiO2-x could provide excess sites for sorption, activation and conversion of CO2. Furthermore, the generated Ti3+ ions in the Y@S TiO2 structure as well as connecting of structure with LDH plates, can facilitate the charge separation and decrease the band gap of nanoarchitecture to the visible region.
关键词： Solar fuel,Oxygen vacancy,Photocatalysis,CO2 conversion,Nanoarchitectures
更新于2025-09-23 15:22:29
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A Switching Sequence for Unary Digital-to-Analog Converters Based on a Knight's Tour
摘要： This paper proposes a new switching sequence with the asymmetric placement of weighting elements for a unary digital-to-analog converter (DAC). The proposed sequence is based on a so-called knight’s tour according to the modified Warnsdorf’s rule. To estimate the efficiency of the proposed switching sequence, a 10-bit resistive DAC has been designed and fabricated in the UMC 180-nm technology. Experimental results show that in comparison with an array of weighting elements without compensation of the systematic error, the proposed switching sequence reduces the maximal integral (INL) and the mean INL by 20% on the average in the temperature range from ?40 °C to 85 °C. Besides that, the maximal INL does not depend on the temperature, while the mean INL decreases with temperature increase.
关键词： CMOS integrated circuits,digital–analog conversion,nonlinear circuits,dynamic range
更新于2025-09-23 15:22:29
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Contribution to the System Design of Contactless Energy Transfer Systems
摘要： In this contribution, a design procedure that is applicable to many kinds of wireless or contactless energy transfer systems is proposed. The design procedure is limited to near field wireless energy transfer systems in resonant operation. For this purpose, the input impedance and voltage transfer function of different natural frequencies are calculated analytically, and moreover, the behavior of the system is described. Following three issues lead to a readily applicable design procedure. First, the knowledge of the transfer functions. Secondly, the knowledge of basic magnetic properties and lastly, the known influence of harmonics according to rectifier and inverter. This design procedure is demonstrated with two hardware setups.
关键词： Inductive power transmission,power conversion harmonics,transfer functions,resonant inverters,inductive,charging
更新于2025-09-23 15:22:29
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Optomechanical Kerker Effect
摘要： Tunable directional scattering is of paramount importance for operation of antennas, routing of light, and design of topologically protected optical states. For visible light scattered on a nanoparticle, the directionality could be provided by the Kerker effect, exploiting the interference of electric and magnetic dipole emission patterns. However, magnetic optical resonances in small sub-100-nm particles are relativistically weak. Here, we predict inelastic scattering with the unexpectedly strong tunable directivity up to 5.25 driven by a trembling of a small particle without any magnetic resonance. The proposed optomechanical Kerker effect originates from the vibration-induced multipole conversion. We also put forward an optomechanical spin-Hall effect, the inelastic polarization-dependent directional scattering. Our results uncover an intrinsically multipolar nature of the interaction between light and mechanical motion and apply to a variety of systems from cold atoms to two-dimensional materials to superconducting qubits. An application for engineering of chiral optomechanical coupling and nonreciprocal transmission at nanoscale is proposed.
关键词： Directional scattering,Multipole conversion,Kerker effect,Optomechanics,Spin-Hall effect
更新于2025-09-23 15:22:29
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A Hybrid MMC-Based Photovoltaic and Battery Energy Storage System
摘要： This paper proposes a new configuration and its control strategy for a modular multilevel converter (MMC)-based photovoltaic (PV)-battery energy storage (BES) system. In the MMC-based PV-BES system, each PV submodule is interfaced from its dc side with multiple PV generators using isolated dual active bridge (DAB) dc-dc converters. One BES system is embedded into each arm of the converter and is connected to the dc port of the associated BES submodule using multiple isolated DAB converters. The embedded BES systems are used to smooth the output power of the PV generators and limit the rate of change of the power delivered to the host grid. Moreover, they enable compensation of power mismatches between the arms and legs of the system by exchanging power with the arms of the converter. The paper then proposes a hybrid power mismatch elimination strategy using a combination of power exchange with the arms of the converter and internal power flow control of the MMC. The proposed hybrid power mismatch elimination strategy employs BES systems and differential currents to compensate power mismatches and transfer power between the arms and legs of the converter, respectively. The effectiveness of the proposed power smoothing technique using the embedded BES systems and hybrid power mismatch elimination strategy is demonstrated using time-domain simulations conducted on a switched model of the PV-BES system in PSCAD/EMTDC software environment.
关键词： control,modular multilevel converter,power electronics,battery energy storage,photovoltaic,power mismatch,Differential current,energy conversion,integration
更新于2025-09-23 15:22:29
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A Dual-Discrete Model Predictive Control-based MPPT for PV systems
摘要： This paper presents a method that overcomes the problem of the confusion during fast irradiance change in the classical MPPTs as well as in model predictive control (MPC)-based MPPTs available in the literature. The previously introduced MPC-based MPPTs take into account the model of the converter only, which make them prone to the drift during fast environmental conditions. Therefore, the model of the PV array is also considered in the proposed algorithm, which allows it to be prompt during rapid environmental condition changes. It takes into account multiple previous samples of power, and based on that is able to take the correct tracking decision when the predicted and measured power differ (in case of drift issue). After the tracking decision is taken, it will be sent to a second part of the algorithm as a reference. The second part is used for following the reference provided by the first part, where the pulses are sent directly to the converter, without a modulator or a linear controller. The proposed technique is validated experimentally by using a buck converter, fed by a PV simulator. The tracking efficiency is evaluated according to EN50530 standard in static and dynamic conditions. The experimental results show that the proposed MPC-MPPT is a quick and accurate tracker under very fast changing irradiance, while maintaining high tracking efficiency even under very low irradiance.
关键词： Buck converter,dc-dc power conversion,Photovoltaic systems,Double cost function,Maximum power point tracking,Drift,EN50530 standard,MPC
更新于2025-09-23 15:22:29