Array Arrangement Research Articles

Printing on Particles: Combining Two-Photon Nanolithography and Capillary Assembly to Fabricate Multimaterial Microstructures.

Additive manufacturing at the micro- and nanoscale has seen a recent upsurge to suit an increasing demand for more elaborate structures. However, the integration of multiple distinct materials at small scales remains challenging. To this end, capillarity-assisted particle assembly (CAPA) and two-photon polymerization direct laser writing (2PP-DLW) are combined to realize a new class of multimaterial microstructures. 2PP-DLW and CAPA both are used to fabricate 3D templates to guide the CAPA of soft- and hard colloids, and to link well-defined arrangements of functional microparticle arrays produced by CAPA, a process that is termed "printing on particles." The printing process uses automated particle recognition algorithms to connect colloids into 1D, 2D, and 3D tailored structures, via rigid, soft, or responsive polymer links. Once printed and developed, the structures can be easily re-dispersed in water. Particle clusters and lattices of varying symmetry and composition are reported, together with thermoresponsive microactuators, and magnetically driven "micromachines", which can efficiently move, capture, and release DNA-coated particles in solution. The flexibility of this method allows the combination of a wide range of functional materials into complex structures, which will boost the realization of new systems and devices for numerous fields, including microrobotics, micromanipulation, and metamaterials.

Base Station MIMO Antenna in 1 × 6 Array Configurations with Reflector Design for Sub-6 GHz 5G Applications

In this article, a base station array antenna in 1 × 6 configuration is proposed for sub-6 GHz 5G applications. Analyses have been performed on two orthogonally arranged dipole strips, a balun with various feeding schemes, and a reflector with different side walls. At the balanced feed position, aluminum is used to connect the feeding balun and the dipole through a hole. A single crossed antenna element of size 66 × 66 × 78 mm3 is fabricated using an FR-4 substrate with a dielectric constant of 4.4, 1.6 mm thickness, and an operating frequency band from 3.2 to 5.22 GHz. The radiating element provides a stable and high gain of 11–18 dB using reflectors with sidewalls. The proposed element is simulated, and its electrical downward tilt is investigated for a 1 × 6 array arrangement with dimensions of 642 mm × 112 mm × 90 mm. Various radiation performance parameters are measured, such as gain, FBR (>26 dB), HPBW, and XPD (>11.5 dB) at 60° in the H-plane. A reflection coefficient of less than −15 dB and port-to-port isolation of greater than 27 dB are achieved. Simulation and measurement of radiation patterns are performed for the operating frequencies of 3.2, 4.2, and 5.2 GHz.

Cooling performance of a teardrop cross-section Kagome truss-filled array jet impingement composite cooling structure

The target surface is coupled to truss rods and the jet space to form a robust overall structure using 30 Kagome truss cores with 5 × 6 array configurations. This paper focuses on the cooling performances of the array jet impingement structure with the Kagome truss array in a 3D printing heat exchanger at Reynolds numbers (Re) ranging from 5000 to 50,000. The cooling characteristics of the Kagome truss-filled array jet impingement with a circular cross-section (CC) and a teardrop cross-section (TC) are comparatively studied through experiments and numerical simulations. The effects of the truss array arrangements, the diameter of the cross-section (d) and the trailing edge angle (α) on the cooling characteristics are studied by numerical simulation in the TC, where the truss array arrangements include an in-line arrangement and a staggered arrangement, d = 1–3mm and α = 45°–90°. The results indicate that when d is 3 mm and α is 45°, the TC has better cooling performance compared to the CC. The TC in the staggered arrangement has a smaller pressure loss coefficient (Cp), while that in the in-line arrangement has a higher average Nusselt number on the impingement target surface (Nuave). The comprehensive thermal factor (F) is increased by 6.58%–21.00% with the increase in d from 1 mm to 3 mm and decreased by 7.16%–8.90% with the increase in α from 45° to 90° in the TC. Two empirical correlations for the Nuave and the Cp for the TC have an accuracy of about 5%.

A method of generating arbitrary uniform fields based on angular spectrum domain and time inversion

Existing uniform fields are usually based on the special arrangement of the array antenna. The uniform fields generated by flat-top beam shaping in angular far-field area or by point focusing in near-field area are directly subject to the array configuration and cannot be flexibly controlled. This paper presents a method of generating uniform field based on the combination of angular spectral domain and improved time reversal technique. This method is not limited by the array arrangement. It can generate a uniform field of specified size, shape and deflection angle in the same array arrangement at any position, including the near-field region. In this work, the reason why this method is not limited by array arrangement is explained theoretically. Secondly, the ability of the fixed array configuration to generate multiple uniform fields is validated numerically. Finally, the time-reversal technique of reversal signal amplitude reciprocal weighting is introduced. The problem of deterioration of uniform field flatness, caused by amplitude decay and phase delay during the generation of uniform field, is solved through this technology. The results show that the quality of the synthesized field is related to the main lobe and sidelobe information of its corresponding angular spectrum domain envelope, and the generated any uniform field must contain at least half of the angular spectrum domain main lobe information and half of the sidelobe information. This method can flexibly control the position, size, shape and deflection angle of one-dimensional and two-dimensional uniform field, which provides a new way to flexibly generating uniform fields.

Measurement of the Thin Liquid Film at the Wet-Gas Outlet of the Supersonic Separator by FPC Conductance Sensor

Gas-liquid two-phase flow widely exists in the natural gas transportation industry. Accurate measurement of the liquid film is conducive to enhancing the efficiency and economy of supersonic separators. Therefore, a flexible printed circuit (FPC) liquid film conductance sensor based on array arrangement is designed. Firstly, the geometric parameters of sensors are optimized by the finite element method. The modules of electrical signal excitation and collection system based on FPGA are designed. A liquid film calibration device is built to calibrate the FPC sensor, the liquid film thickness is fitted through calibration experiments, and the fitting curve error is within ±5.0 %. Secondly, to analyze the liquid film thickness and velocity at the wet-gas outlet section of the supersonic separator, serval experiments are carried out in different working conditions, and the signals of liquid film thickness are processed by time and frequency domain analysis. The results reveal that the liquid film thickness has a bimodal characteristic, where the thickness of the thin base layer is about 70 μm, and fluctuating layer thickness is related to working conditions. The normalized energy ratio and fluctuation characteristics significantly changed under different frequency bands. At the same time, the existence of shock waves seriously influences the generation of liquid film, resulting in a decrease in the liquid film thickness seriously. Last, the cross-correlation algorithm is used to analyze the liquid film velocity. The different signal transmitter and receiver electrode orders can realize the velocity measurement in different directions. The experimental results show that the liquid film velocity at the outlet of the supersonic separator maintains at 54.8 mm/s ~ 339.0 mm/s when the back pressure ranges from 0.350-0.717, the maximum <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RMSE</i> of flow direction velocity is 4.51 mm/s and the maximum <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RMSE</i> of circumferential direction velocity is 3.38 mm/s.

High-Power and High-Speed Ge/Si Traveling-Wave Photodetector Optimized by Genetic Algorithm

We experimentally demonstrate a 4-stage and an 8-stage Ge/Si distributed traveling-wave photodetectors (TWPDs) with high RF output powers and large bandwidths. The genetic algorithm is utilized to synergistically optimize multiple relevant design parameters, including the dimension of the coplanar waveguide electrode and the aperiodic arrangement of the PD array. After the genetic algorithm optimization, the 3dB bandwidth of the 4-stage TWPD is improved from 46 GHz to 54 GHz under the constraint that the bandwidth of the unterminated single PD element is 50 GHz. Meanwhile, the 3dB bandwidth of the 8-stage TWPD is improved from 33 GHz to 40 GHz. A good agreement between measured and calculated frequency responses is obtained. The measured maximum RF output powers of the aperiodic 4-stage and 8-stage TWPDs at 30 GHz are 2.5 dBm and 6.3 dBm, respectively. Furthermore, the effectiveness of our design methodology is verified by measurement results of devices fabricated at different silicon photonics foundries.

Influence of sensor array on MS/AE source location accuracy in rock mass

As the mining depth increases, rock dynamic disasters become increasingly prominent. Microseismic monitoring has become an important technical means to monitor rock dynamic disasters, such as rockburst and roof collapse. The sensor array is the first step of signal acquisition and will seriously affect source location accuracy. The significant studies on error factors caused by sensor array arrangement to the location accuracy of microseismic (MS) and acoustic emission (AE) sources were discussed and summarized. The influences of the number of sensors, configuration of sensors and distance between sensors and source on MS/AE source location accuracy were analyzed. Subsequently, some principles of sensor arrays were given by combining with engineering practices and laboratory testing, and confirmed by a field application. In addition, the optimal arrangement scheme was discovered by considering the factors affecting the number, shape, and distance of sensors, which can greatly adjust the signal acquisition effect and improve the source location accuracy. Finally, some challenges and the corresponding coping strategies of sensor arrays were prospected to improve the MS/AE source location accuracy.

Reconfigurable Plasma Composite Absorber Coupled With Pixelated Frequency Selective Surface Generated by FD-CGAN

Conventional plasma absorbers are challenging to obtain high electron density and sizeable spatial scale for effective absorption while meeting the applied requirements of low profile and low power consumption. Although the frequency selective surface (FSS) has proved to realize a lower profile of plasma absorber with some empirical patterns adequately, the issue of the FSS design matching the dispersion distribution of complicated plasmas is still in suspense. A reverse prediction method referenced as the forecast and design Conditional Generative Adversarial Network (FD-CGAN) is proposed to generate a pixelated FSS between double-layer plasma periodic arrays. The reflection attenuation characteristics examined by experiments show that the addition of the FSS makes the coupling absorption effect surpass that of either pixelated FSS or plasma solely. Measurements in reconfigurable working modes and array arrangements demonstrate that the proposed configuration maximizes absorption effectiveness in the same profile, accompanied by the simulation. An interfacial void model is proposed to assist the design of the composite absorbing structure, together with an equivalent circuit for the hybrid absorber including periodic patterns with stochastic distribution characteristics, which analyze the absorption effect of the composite structure. The study provides a new approach for various microwave applications, including multilayer radar-absorbing structures, plasma-based stealth technology, and reconfigurable filters.

A Multi-Polarization Series-Fed Antenna Array Based on Eccentric Ring

A multi-polarization series-fed antenna working at 10 GHz is presented in this paper. The patch elements are built by eccentric rings which can realize the performance of circular polarization. The dual-port feeding allows us to switch the polarization of the antenna. The right-hand circular polarization (RHCP), left-hand circular polarization (LHCP), and Linear polarization (LP) polarization can be realized by properly feeding form. The changing of antenna polarization without switch controlling. Owing to the circular array arrangement, the antenna can form a compact structure. The key features of this array are multi-polarization and traveling-wave series-fed performance. The axial ratios are lower than 3dB measured. The |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> | is lower than -14 dB in the mentioned bandwidth. Then, a 4 × 4 MIMO array which has compact structure is designed and simulated. The circular array is processed and measured. The experimental and simulation results are in good agreement.

Adjustable Sound Absorber of Multiple Parallel-Connection Helmholtz Resonators with Tunable Apertures Prepared by Low-Force Stereolithography of Photopolymer Resin.

The variable noise spectrum for many actual application scenarios requires a sound absorber to adapt to this variation. An adjustable sound absorber of multiple parallel-connection Helmholtz resonators with tunable apertures (TA-MPCHRs) is prepared by the low-force stereolithography of photopolymer resin, which aims to improve the applicability of the proposed sound absorber for noise with various frequency ranges. The proposed TA-MPCHR metamaterial contains five metamaterial cells. Each metamaterial cell contains nine single Helmholtz resonators. It is treated as a basic structural unit for an array arrangement. The tunable aperture is realized by utilizing four segments of extendable cylindrical chambers with length l0, which indicates that the length of the aperture l is in the range of [l0, 4l0], and that it is tunable. With a certain group of specific parameters for the proposed TA-MPCHR, the influence of the tunable aperture with a variable length is investigated by acoustic finite element simulation with a two-dimensional rotational symmetric model. For the given noise spectrum of certain actual equipment with four operating modes, the TA-MPCHR sample with a limited total thickness of 40 mm is optimized, which is made of photopolymer resin by the low-force stereolithography, and its actual average sound absorption coefficients for the frequency ranges of 500-800 Hz, 550-900 Hz, 600-1000 Hz and 700-1150 Hz reach 0.9203, 0.9202, 0.9436 and 0.9561, respectively. Relative to common non-adjustable metamaterials, the TA-MPCHR made of photopolymer resin can reduce occupied space and improve absorption efficiency, which is favorable in promoting its practical applications in the noise pollution prevention.

Modern Electromagnetic Field Theory and Its Application in Future Wireless Communication

With the advent of the 5G era, more and more technologies in life are applied to the technological development and theory of antennas. Waveform constraints. These basic applications are obtained due to the natural seismic source and the continuous arrangement and combination of arrays. In this article, we first discuss the spherically symmetric electric field distribution of antenna elements in space, and then discuss the influence of a circular array on the electromagnetic intensity of the space radiated field. At the same time, the basic characteristics of waveform restraint, array radar and array telescope are discussed. Afterwards, from a theoretical point of view, the physical properties and radiation characteristics of the near-field induction field and radiation field of the factory around the vibrator were analyzed quantitatively and qualitatively. Later, I discussed the relationship between an annular array and the eddy current. Through theoretical derivation and excitation factors, we used the original radiation equation to derive the Bessel function, and used a computer to make a simulation to explore the factors that can affect the array radiation.

Novel Hybrid Photovoltaic Array Arrangement to Mitigate Partial Shading Effects

Novel Hybrid Photovoltaic Array Arrangement to Mitigate Partial Shading Effects

Comparative study of a perovskite solar cell using different aperiodic arrangements of plasmonic nanoparticles

In this research work, the optimized Fibonacci, Thue-Mors, and Gaussian-based aperiodic arrays of plasmonic nanoparticles were studied to improve the performance of thin perovskite solar cells. Here, the effect of different types of deterministic aperiodic plasmonic arrays on the optical properties of perovskite absorbers is analyzed. At first, different polytypes of perovskite material consistent (C6H5C2H4NH3)2PbI4, CH3NH3FeI2Br, CH3NH3FeI3, CH3NH3PbBr3, CH3NH3PbCl3, and CH3NH3PbI3 as the active layer of a solar cell were analyzed. The results show that CH3NH3PbI3 has higher absorption spectra than other cases. Then, different types of metals (Ag, Au, Cu, Al) as the form of periodic arrays are simulated and Ag was selected to form our arrays according to the Fibonacci, Thue-Mors, Gaussian, and periodic array arrangement. To form such arrays, 36 nanoparticles per cell were used and the effect of network constant (closest distance between the nanoparticles) was evaluated. Our results confirm that all cases of the Fibonacci, Thue-Mors, and Gaussian arrangement improve the photocurrent, while the photocurrent of the Thue-Mors arrangement is higher than in other cases. These findings reveal that it is possible to improve the performance of perovskite solar cells using a realistic plasmonic array.

Design of Circular Patch Array Microstrip Antenna Using Slot for ISM Band

This paper presents a Microstrip Antenna Analysis for the ISM Band with a circular patch design with a radius of 17 mm at a frequency of 2,400 – 2.484 GHz. The fabricated array antenna has a very compact width and length of 9.5 x 7.5 cm each. Therefore, an increase in bandwidth on the monopole antenna can be applied to the array arrangement. So to get the best antenna design, two optimizations of antenna size changes are carried out during the simulation: optimization of patch radius and slot length. The radius variation is used to shift the frequency range and slot length for impedance matching, as seen from the S11 value of less than -10 dB. From each change, the best results are taken. Experiments get the best antenna simulation results and are then fabricated. From the measurement results on the fabricated antenna, the lowest S11 value is -19.602 dB, and the gain is 3.52 dBi. The slot technique's optimization process has successfully shifted the frequency to approximately 100 MHz and increased the bandwidth by about 5% or 40 MHz.

Study on fatigue performance of concrete-filled steel tubular K-joints with internal studs

To study the fatigue performance of concrete-filled steel tubular K-joint (CFST K-joint) with internal studs, fatigue tests on CFST K-joint without internal studs, CFST K-joint with array arrangement internal studs (CFST KSA-joint), and CFST K-joint with circular arrangement internal studs (CFST KSC-joint) were conducted. The finite element models of CFST K-joints with studs were established. The hot-spot stress distributions, fatigue crack growth processes, and fatigue failure modes of the joints mentioned above were comparatively studied. The study showed that the maximum hot-spot stress of the CFST K- and KSA-joints appeared at the crown toe, while that of the CFST KSC-joint occured at the position of 45°. As compared with CFST K-joints, the CFST KSA- and KSC-joint specimens had 34% and 12% reductions in hot-spot stress, respectively. At the location of the internal studs, the hot-spot stress decrease significantly. By reducing the chord deformation and peeling arc length, the internal studs reduce the hot spot stress and increase the fatigue life. The fatigue life of the CFST KSA-joint specimen with array internal studs was 101% higher than that of the CFST K-joint specimen. By applying the circular internal studs, the fatigue life of the CFST KSC-joint specimen was 97% higher than the CFST KSA-joint specimen with array internal studs. The internal studs delay the occurrence of fatigue cracks, and change the propagation path of fatigue cracks along the length of intersecting welds into the direction of steel tube wall thickness, therefore, improving the fatigue life of K-joints.

High strength, self-healing polyurethane elastomer based on synergistic multiple dynamic interactions in multiphase

Inspired by some biological phenomena, self-healing materials has been made great progress over the past decades. However, it is challenging to establish an adaptable strategy to achieve a good tradeoff between mechanical strength and self-healing ability. Herein, we reported a self-healing polyurethane elastomer (PPG-UPy-SS) with desirable mechanical performance and wonderful self-healing capacity via incorporating synergistic multiple dynamic interactions in multiphase. The 2-amino-5-(2-hydroxyethyl)-6-methylpyrimidin-4-ol (UPy) motif was introduced into the PPG segment to keep the mechanical performance profiting from the regular arrangement of hydrogen-bonding array and microphase separation benefited from π-π stacking of UPy dimers. 4-aminophenyl disulfide (APDS) was embedded into the loosely stacked amorphous region to increase the mobility of the chain segment to improve self-healing performance. The optimized sample PPG-UPy50%-SS50% possesses high tensile strength and fracture toughness of 18.2 MPa and 57.3 MJ m−3, and satisfactory self-healing efficiency of 99% and 96% (10 h at 80 °C), respectively.

Multi-objective Optimization of Non-invasive Voltage Sensor Considering Sensitivity, Array Arrangement, and Cost

Multi-objective Optimization of Non-invasive Voltage Sensor Considering Sensitivity, Array Arrangement, and Cost

A novel online method for locating fault coil in direct‐drive permanent magnet synchronous motor with inter‐turn short‐circuit fault using search coil array

This study presents a fault coil localisation approach for a direct-drive permanent magnet synchronous motor (DDPMSM) with inter-turn short-circuit fault (ISF) using the search coil (SC) array. The SCs are wound around specific stator tooth of DDPMSM through the proposed SC array arrangement principle, which reduces the invasiveness of the fault coil localisation method. The SCs are classified as several search coil groups (SCGs), the differential between SC back electromotive forces (EMFs) in the same SCGs (δ1) and SC residual back EMF (δ2) are used as fault indicators for ISF localisation. The peak values extracted from δ1 and δ2 are the basis for diagnosing ISF. Hence, the proposed approach does not need a complicated signal processing algorithm, and it is less complex. First, the SC back EMF analytical model is developed to investigate the mapping relationship between the back EMF of each SC and fault coil location. Second, fault coil localisation indicators for ISF are analysed based on the proposed analytical model, and the exact ISF localisation approach is presented. Finally, two basic installation units and the arrangement principle of SC array in DDPMSM are proposed. Simulation and experimental results justify the effectiveness of the selected fault indicators and the feasibility of the proposed SC array for diagnosing ISF.

Wireless Flexible Magnetic Tactile Sensor with Super-Resolution in Large-Areas.

Tactile recognition is among the basic survival skills of human beings, and advances in tactile sensor technology have been adopted in various fields, bringing benefits such as outstanding performance in manipulating objects and general human-robot interactions. However, promoting enhanced perception of the existing tactile sensors is limited by their sensor array arrangement and wire-connected design. Here we present a wireless flexible magnetic tactile sensor (FMTS) consisting of a multidirection magnetized flexible film (perception module) and a contactless Hall sensor (signal receiving module). The flexible magnetic film is composed of NdFeB microparticles and soft silicone elastomer microparticles, and it transfers the unambiguous transduction of external force position and magnitude into magnetic signals. Benefiting from the specific magnetization arrangement and clustering algorithm, only one Hall sensor is needed in FMTS to perceive the magnitude and position of the contact spot simultaneously with super-resolution (2.1 mm average error) on a large area (3600 mm2), and the effective working distance is also greatly extended (∼30 mm), allowing for the full softness and adaptability to diverse conditions. We anticipate that this design will promote the development of soft tactile sensors and their integration into human-robot interaction and humanoid robot perception.

A Simple Method to Build High Power PCSEL Array with Isolation Pattern Design

Photonic crystal surface-emitting lasers (PCSELs) hold promising properties of both edge emitting lasers (EELs) and vertical-cavity surface-emitting lasers (VCSELs). They possess high output power while radiating light vertically, being thought of as the next generation laser source. One of the main advantages of PCSELs is their scalability of size and power, which makes them applicable to high power applications or long-distance detection. However, due to problems such as current injection and mode competition, there are limits on their dimensions. To further increase the power, the capability of two-dimensional array integration paves the way. In this work, we demonstrate a new method to fabricate PCSEL arrays by defining an isolation pattern. We also investigate the influence of aperture size and array arrangement on lasing performance.