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- 2018
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- periodic paperclip-shaped structure
- antenna array
- mutual coupling reduction
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- Electronic Science and Technology
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- UIN Suska Riau
- Xi'an University of the Science and Technology
- University of Riau
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[IEEE 2018 IEEE International Conference on RFID Technology & Application (RFID-TA) - Macau, Macao (2018.9.26-2018.9.28)] 2018 IEEE International Conference on RFID Technology & Application (RFID-TA) - Auditing of Ultra Dense RFID Straws in Cryogenic Container at -196°C
摘要： This paper presents a new auditing system scheme for cryopreservation based on radio frequency identification (RFID) at temperature of -196 oC. Conventional approaches such as hand written labels or printed barcodes suffer from the significant manual labor work and freeze-thaw-damaging risk of the sample. The proposed scheme integrates miniaturized RFID electronic devices and antennas in the thin cryogenic straws without significantly changing their dimensions. In addition, 900 MHz frequency band is chosen for long reading range, which eliminates the need to take the preserved biological samples out of liquid nitrogen and minimizes the damaging risk. Four most important technical aspects for the system have been identified and investigated: 1. The link budget is evaluated by FDTD numerical simulations to make sure the RF signal strength meets the requirement for the reading range. 2. The total efficiency of small and tightly coupled RFID dipole antennas is studied and obtained by simulations. 3. The current-voltage behaviors of two types of transistors in typical RFID electronics have been characterized by measurements to identify the suitable transistor type for reliable circuit designs at -196 oC. 4. The easy-to-access and anti-collision reading system for fast data collection is analyzed. The obtained results indicate that the proposed scheme is feasible, which can be beneficial for the relevant scientific fields.
关键词： coupling,FET,cryopreservation,RFID,antennas
更新于2025-09-23 15:22:29
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The Magnetic Properties of 1111-type Diluted Magnetic Semiconductor (La1?xBax)(Zn1?xMnx)AsO in the Low Doping Regime
摘要： We investigated the magnetic properties of (La1?xBax)(Zn1?xMnx)AsO with x varying from 0.005 to 0.05 at an external magnetic field of 1000 Oe. For doping levels of x ≤ 0.01, the system remains paramagnetic down to the lowest measurable temperature of 2 K. Only when the doping level increases to x = 0.02 does the ferromagnetic ordering appear. Our analysis indicates that antiferromagnetic exchange interactions dominate for x ≤ 0.01, as shown by the negative Weiss temperature fitted from the magnetization data. The Weiss temperature becomes positive, i.e., ferromagnetic coupling starts to dominate, for x ≥ 0.02. The Mn-Mn spin interaction parameter |2J/kB| is estimated to be in the order of 10 K for both x ≤ 0.01 (antiferromagnetic ordered state) and x ≥ 0.02 (ferromagnetic ordered state). Our results unequivocally demonstrate the competition between ferromagnetic and antiferromagnetic exchange interactions in carrier-mediated ferromagnetic systems.
关键词： ferromagnetic ordering,ferromagnetic coupling,antiferromagnetic exchange interaction,carrier-mediated
更新于2025-09-23 15:22:29
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Three-Way Multiple-Mode Cavity Filtering Crossover for Narrowband and Broadband Applications
摘要： In this paper, the design of a cavity crossover with three intersecting channels is presented. The three fundamental modes of a cavity resonator, namely, TE011, TE101, and TM110 modes, are adopted to resonate at each of three channels, respectively. Due to the modal orthogonality of these fundamental modes, high isolation among three channels can be achieved. Two kinds of crossovers, for narrowband and broadband applications, are presented. For the narrowband case, the proposed crossover resonates at 2.91 GHz with the fractional bandwidth of 1.4%. For the broadband case, the proposed crossover resonates at 3 GHz with the fractional bandwidth of 24%. The isolations of both designs reach more than 50 dB. For a proof of concept, the broadband example of the cavity crossover structures is fabricated and measured. A good agreement between the simulated and the measured results verifies the accuracy of the proposed design methodology.
关键词： slot coupling,multiple mode,Broadband,three channel,cavity crossover,triple-mode rectangular cavity,resonator (TMR)
更新于2025-09-23 15:22:29
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The Temperature Dependences of the Electron-Piezoelectric Potential Phonon Interacting System of Quasi Two Dimensional System in GaN and ZnS
摘要： We investigated theoretically the temperature dependence of the quantum optical transition of quasi 2-Dimensional Landau splitting system, in GaN and ZnS. We apply the Quantum Transport theory (QTR) to the system in the con?nement of electrons by square well con?nement potential. We use the projected Liouville equation method with Equilibrium Average Projection Scheme (EAPS). Through the analysis of this work, we found the increasing properties of Quantum Transition Line Shapes (QTLSs) and the Quantum Transition Line Widths (QTLWs) of CdS and GaN with the temperature we also found that QTLW, (cid:2)(cid:3)T (cid:4) of ZnS < (cid:2)(cid:3)T (cid:4) of GaN in (cid:5) = 394 (cid:6)m.
关键词： Quantum Transport Theory,Quantum Transition Line Widths (QTLW),Quantum Transition Line Shapes (QTLS),GaN and ZnS,Cyclotron Resonance,Equilibrium Average Projection Scheme (EAPS),Electron Phonon Coupling System
更新于2025-09-23 15:22:29
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Equivalent-Circuit Model with Retarded Electromagnetic Coupling for Meta-Atoms of Wired Metallic Spheres
摘要： This paper describes the equivalent-circuit model of a metamaterial composed of conducting spheres and wires. This model involves electromagnetic coupling between the conductors, with retardation. The lumped-parameter equivalent circuit, which imports retardation to the electromagnetic coupling, is developed in this paper from Maxwell’s equation. Using the equivalent-circuit model, we clarify the relationship between the retardation and radiation loss; we theoretically demonstrate that the electromagnetic retardation in the near-field represents the radiation loss of the meta-atom in the far-field. Furthermore, this paper focuses on the retarded electromagnetic coupling between two meta-atoms; we estimate the changes in the resonant frequencies and the losses due to the distance between the two coupled meta-atoms. It is established that the dependence characteristics are significantly affected by electromagnetic retardation.
关键词： meta-atom,equivalent-circuit model,metamaterial,electromagnetic coupling,radiation,retardation
更新于2025-09-23 15:22:29
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Unusual Electric and Optical Tuning of KTaO <sub/>3</sub> -Based Two-Dimensional Electron Gases with 5d Orbitals
摘要： Controlling electronic processes in low dimension electron system is centrally important for both fundamental and applied researches. While most of the previous works focused on SrTiO3-based two-dimensional electron gases (2DEGs), here we report on a comprehensive investigation in this regard for amorphous-LaAlO3/KTaO3 2DEGs with the Fermi energy ranging from ~13 meV to ~488 meV. The most important observation is the dramatic variation of the Rashba spin-orbit coupling (SOC) as Fermi energy sweeps through 313 meV: The SOC effective field first jumps and then drops, leading to a cusp of ~2.6 T. Above 313 meV, an additional species of mobile electrons emerges, with a 50-fold enhanced Hall mobility. A relationship between spin relaxation distance and the degree of band filling has been established in a wide range. It indicates that the maximal spin precession length is ~70.1 nm and the maximal Rashba spin splitting energy is ~30 meV. Both values are much larger than the previously reported ones. As evidenced by density functional theory calculation, these unusual phenomena are closely related to the distinct band structure of the 2DEGs composed of 5d electrons. The present work further deepens our understanding of perovskite conducting interfaces, particularly those composed of 5d transition metal oxides.
关键词： oxide interfaces,spin-orbital coupling,two-dimensional electron gas,optical gating,gating effect
更新于2025-09-23 15:22:29
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Characteristic Mode Analysis and Design of Wide Band MIMO Antenna Consisting of Metamaterial Unit Cell
摘要： This paper presents a full wave simulation and characteristic mode-based design of a multiple-input-multiple-output (MIMO) antenna at 5.8 GHz for wireless local area network applications. The driven analysis comprises two antennas that are placed orthogonal to each other. A metamaterial unit structure in the form of a rectangular loop resonator is placed around the antenna element to reduce the electromagnetic interference and to increase the isolation between the two monopoles. A characteristic mode technique is employed to find out the dominant mode of the proposed antenna without a feeding port. It was revealed that mode 1 was the dominant mode among the three modes used. The MIMO antenna is constructed and measured using a vector network analyzer. A good isolation of less than 25 dB was attained with a wide impedance bandwidth of 65.5%.
关键词： rectangular loop resonator,multiple-input-multiple-output (MIMO),envelope correlation coefficient,mutual coupling
更新于2025-09-23 15:22:29
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Phonon-assisted tunneling in direct-bandgap semiconductors
摘要： In tunnel ?eld-effect transistors, trap-assisted tunneling (TAT) is one of the probable causes for degraded subthreshold swing. The accurate quantum-mechanical (QM) assessment of TAT currents also requires a QM treatment of phonon-assisted tunneling (PAT) currents. Therefore, we present a multi-band PAT current formalism within the framework of the quantum transmitting boundary method. An envelope function approximation is used to construct the electron-phonon coupling terms corresponding to local Fr?hlich-based phonon-assisted inter-band tunneling in direct-bandgap III-V semiconductors. The PAT current density is studied in up to 100 nm long and 20 nm wide p-n diodes with the 2- and 15-band material description of our formalism. We observe an inef?cient electron-phonon coupling across the tunneling junction. We further demonstrate the dependence of PAT currents on the device length, for our non-self-consistent formalism which neglects changes in the electron distribution function caused by the electron-phonon coupling. Finally, we discuss the differences in doping dependence between direct band-to-band tunneling and PAT current.
关键词： phonon-assisted tunneling,quantum-mechanical modeling,tunnel ?eld-effect transistors,electron-phonon coupling,direct-bandgap semiconductors
更新于2025-09-23 15:22:29
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Hydrolysis kinetics of silane coupling agents studied by near-infrared spectroscopy plus partial least squares model
摘要： A method of Fourier transform near-infrared (FT-NIR) spectroscopy combined with partial least squares (PLS) model was successfully applied to investigate the hydrolysis kinetics of four kinds of silane coupling agents (phenyltriethoxysilane, vinyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3-chloropropyltriethoxysilane) in an acid-catalyzed EtOH system. The fast scanning speed and high sensitivity of the FT-NIR spectroscopy, and the powerful data processing ability of the PLS, enabled the method to quantitatively and accurately catch the fast changing H2O concentration during the hydrolysis processes without delay, realizing the study of the fast-paced hydrolysis reactions of the silane coupling agents. The results showed that electrophilic substitution occurred in the hydrolysis reactions, which followed second-order reactions and greatly depend on the catalyst concentration and reaction temperature. The hydrolysis rate constants, activation energy, and Arrhenius Frequency factors were gained. In conclusion, the FT-NIR PLS model is a powerful tool for hydrolysis kinetics researching of the silane coupling agents.
关键词： partial least squares,Hydrolysis kinetic,silane coupling agent,near infrared
更新于2025-09-23 15:22:29
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Synthesis of 3,4-Biaryl-2,5-Dichlorothiophene through Suzuki Cross-Coupling and Theoretical Exploration of Their Potential Applications as Nonlinear Optical Materials
摘要： We report herein the efficient one-pot synthesis of 3,4-biaryl-2,5-dichlorothiophene derivatives (2a–2i) via a palladium-catalyzed Suzuki cross-coupling reaction. A series of thiophene derivatives were synthesized, starting from 3,4-dibromo-2,5-dichlorothiophene (1) and various arylboronic acids using Pd(PPh3)4 and K3PO4 with moderate to good yields. For further insights about the structure and property relationship, density functional theory (DFT) calculations were performed. A relaxed potential energy surface (PES) scan was performed to locate the minimum energy structure. A frontier molecular orbitals analysis was performed to explain the reactivity of all synthesized derivatives. As the synthesized derivatives had extended conjugations, therefore the first hyperpolarizability (βo) was calculated to investigate their potential as non-linear optical (NLO) materials and significant βo values were found for the 2b and 2g derivatives.
关键词： NLO,Pd (PPh3)4,thiophene,PES,density functional theory,Suzuki cross-coupling reaction
更新于2025-09-23 15:22:29