Notch Structure Research Articles

Development of a Safe and Effective Bacillus thuringiensis-Based Nanobiopesticide for Controlling Tea Pests.

Mg(OH)2 was used as the nanocarrier of the Bacillus thuringiensis (Bt) Cry1Ac protein, and the synthesized Cry1Ac-Mg(OH)2 composites were regular and uniform nanosheets. Nano-Mg(OH)2 could effectively improve the insecticidal effect of the Cry1Ac protein toward Ectropis obliqua. It could enhance the damage degree of the Cry1Ac protein to intestinal epithelial cells and microvilli, induce and enrich the production of reactive oxygen species (ROS) in the midgut, and enhance the degradation of the Cry1Ac protein into active fragments. Furthermore, an anti-rinsing assay showed that the Cry1Ac-Mg(OH)2 composites were bound to the notch structure of the tea leaf surface. The retention of the Cry1Ac protein increased by 11.45%, and sprayed nano-Mg(OH)2 was rapidly absorbed by different tissues of tea plants. Moreover, nano-Mg(OH)2 and composites did not significantly affect non-target organisms. These results show that nano-Mg(OH)2 can serve as a safe and effective biopesticide carrier, which provides a new approach for stable and efficient Bt preparation.

Shape-influenced non-reciprocal transport of magnetic skyrmions in nanoscale channel

Abstract Skyrmions, with their vortex-like structures and inherent topological protection, play a pivotal role in developing innovative low-power memory and logic devices. The efficient generation and control of skyrmions in geometrically confined systems are of paramount importance for the advancement of skyrmion-based spintronic devices. In this study, we focus on investigating the non-reciprocal transport behavior of skyrmions and their interactions with boundaries of various shapes. The shape of the notch structure in the nanotrack significantly impacts the dynamic behavior of magnetic skyrmions. Through micromagnetic simulation, we explore the non-reciprocal transport properties of skyrmions in nanowires with different notch structure.

Mechanosensor for Proprioception Inspired by Ultrasensitive Trigger Hairs of Venus Flytrap.

Mechanosensors, as the core component of a proprioceptive system, can detect many types of mechanical signals in their surroundings, such as force signals, displacement signals, and vibration signals. It is understandable that the development of an all-new mechanosensory structure that can be widely used is highly desirable. This is because it can markedly improve the detection performance of mechanosensors. Coincidentally, in nature, optimized microscale trigger hairs of Venus flytrap are ingeniously used as a mechanosensory structure. These trigger hairs are utilized for tactile mechanosensilla to efficiently detect external mechanical stimuli. Biological trigger hair-based mechanosensilla offer an all-new bio-inspired strategy. This strategy utilizes the notch structure and variable stiffness to enhance the perceptual performance of mechanosensors. In this study, the structure-performance-application coupling relationship of trigger hair-based mechanosensors is explored through experiment and analysis. An artificial trigger hair-based mechanosensor is developed by mimicking the deformation properties of the Venus flytrap trigger hair. This bio-inspired mechanosensor shows excellent performance in terms of mechanical stability, response time, and sensitivity to mechanical signals.

Microcomputed tomographic analysis of the ulnar trochlear notch in medium- and large-breed canine cadavers with and without medial coronoid disease

Medial coronoid disease (MCD) is a common disease often associated with thoracic limb lameness in medium- and large-breed dogs. The term MCD includes subchondral changes of the medial coronoid process (MCP), as well as pathologies of both cartilaginous surfaces. As there are only a few comprehensive and detailed studies on the trabecular structure of the medial coronoid, the goal of this study was to compare the trabecular structure of the ulnar trochlear notch of canine cadavers with and without MCD using different micro-computed tomographic (micro-CT) parameters.Fifty-eight elbow joints from 29 canine cadavers of MCD-predisposed and non-predisposed breeds (control group) were examined radiographically, macroscopically and by microcomputed tomography. The study included elbow joints of eight Labrador Retrievers (21.6–37 kg), seven Golden Retrievers (26.3–42 kg), seven Bernese Mountain dogs (31–47 kg) and seven dogs of non-predisposed breeds (19.7–52 kg) (control group). The final diagnosis of MCD was based on necropsy and micro-computed tomographic examinations. Micro-CT examinations were performed using XtremeCT II (Scanco Medical, Zurich, Switzerland) and the following parameters were examined: bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular number (Tb.N), connectivity density (Conn.D) and degree of anisotropy (DA).Twenty-four elbows of 44 elbows of the predisposed breeds (Labrador Retrievers, Golden Retrievers Bernese Mountain dogs) showed subchondral changes and lesions of the cartilage surfaces. The result of this study is a higher density (BV/TV) of the trabecular bone of the ulnar trochlear notch in elbows affected by MCD compared to the control group. The increased density due to trabecular reconstruction in the ulnar trochlear notch is likely the result of selectively increased loading during life.

Triaxial piezoresistive force sensor probe with high sensitivity and stiffness using 3D notch structure

This paper proposes a microelectromechanical system triaxial piezoresistive force sensor probe with high sensitivity and stiffness. The sensor probe is composed of a cantilever and four supporting beams. Two of the four beams had horizontal notch parts at the root, and sidewall-doped piezoresistors were utilised to detect the in-plane deformation. There was a vertical notch at the root of the remaining two beams and a surface-doping piezoresistor in one beam to detect the out-of-plane deformation. Thus, the proposed sensor probe measures the three directional forces applied to the cantilever tip with high sensitivity and stiffness owing to the corresponding piezoresistive notch structures. We demonstrate a fabrication process that forms the notch structure and the surface and sidewall doping methods. Our fabricated device was confirmed capable of measuring triaxial forces with a force resolution at the sub-micro-Newton level.

A Miniaturized Wearable Antenna With Five Band-Notched Characteristics for Medical Applications

In this paper, a miniaturized wearable antenna is proposed, which has five band-notched characteristics. The antenna uses Rogers 5880 as the dielectric substrate, with a thickness of 0.508mm. Due to its thickness, the antenna can be bent slightly and used in the wearable field. The antenna is fed by a microstrip line with an input impedance of 50 ohms. Through the design of notch structures inside the radiating patch, on either side of the feed line, and on the bottom of the substrate, five notch bands are made possible. More notch bands can be produced by employing a new structure which produces two notch bands as well as adding metal on the substrate's sides that allows current to be introduced into the notch structures on the bottom of the substrate. Based on this, it is possible to achieve great space utilization and little interaction amongst notch structures. The proposed antenna has overall size of 30x25x0.508mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> and covers the entire UWB spectrum from 2.56 GHz to 12.7 GHz except notch bands from 2.58 GHz to 3.21 GHz, 4.05 GHz to 4.29 GHz, 5 GHz to 5.64 GHz, 8.60 GHz to 9.05 GHz, 9.20 GHz to 10.32 GHz. By applying the antenna to the doctor's chest badge, the number of swiping cards by hands can be reduced, which is convenient and avoids bacterial pollution. Thus, the antenna has a useful purpose in the medical development.

Impact of Notch Structures on Transfer Characteristics of AlGaN/GaN HEMTs: A Simulation Study

Lateral GaN devices, with a substantial critical breakdown field and increased mobility of two-dimensional electron gas (2DEG), are particularly promising for future power applications. Despite low power consumption by design, further improvements are required in numerous areas, including reliability concerns and switching loss, usually contributing to significant power loss. The research objective concerns the impact of different notch structures on the transfer characteristics of GaN-based high-electron-mobility transistor (HEMT) devices. Thirteen simulated models were produced using COMSOL Multiphysics, incorporating the electrical, structural, and piezoelectric effects of the device. From the results, notch-structure devices demonstrated better electrical characteristics than devices using conventional architecture, particularly a model with a double-notch design. Higher transconductance and maximum drain current were among the improvements, benefiting from the notch structure at the barrier layer.

Position-reconfigurable pinning for magnetic domain wall motion

Precise control of magnetic domain wall (DW) motion is crucial for DW-based spintronic devices. To date, artificially designed DW pinning sites, such as notch structures, have been used to precisely control the DW position. However, the existing DW pinning methods are not reconfigurable because they cannot change the position of pinning site after being fabricated. Herein, a novel method for attaining reconfigurable DW pinning is proposed, which relies on the dipolar interactions between two DWs located in different magnetic layers. Repulsion between DWs in both layers was observed, indicating that one of the DWs acts as a pinning barrier for the other. Because the DW is mobile in the wire, the position of pinning can be modulated, thereby resulting in reconfigurable pinning that was experimentally demonstrated for current-driven DW motion. These findings provide additional controllability of DW motion, which may expand the functionality of DW-based devices to broader spintronic applications.

Enhanced InP-based Gunn Diodes with Notch-d-doped Structure for Low-THz Applications

In this work, Monte Carlo simulation is performed for InP Gunn diode with a notch-d-doped structure. It is found that the presence of the d-doped layer has improved the Gunn diode performance significantly as compared to the conventional notch structure. The d-doped effect caused an increment in the fundamental operating frequency and current harmonic amplitude in InP Gunn diodes by modifying the electric field profile within the device. An InP notch-d-doped Gunn diode with device length of 800 nm under 3V DC bias is capable of producing AC current signal of 287 GHz, reaching the THz region, with its harmonic amplitude being 5.68×108 A/m2. It is observed that InP-based notch-d-doped Gunn diode is able to generate signals at a higher operating frequency with a larger output power as compared to that of GaAs due to the higher electron drift velocity and threshold field in InP material.

Effect of Notch Structure and Notch Bottom Diameter on the Tensile Load of a Certain GH4169 Notch Bolt for a Device for Longitudinal Separation of Fairing

The effect of the notch structure and bottom diameter of a GH4169 notch bolt for an explosive separation device used for longitudinal separation of the fairing, and GH4169 strength range on the tensile load was studied by combing simulations with tests. The results show that the V-shaped, arc-shaped and square notch structures can improve the tensile load of the bolt but to a lesser degree in sequence, and the arc-shaped notch structure performs best in terms of tensile load, fracture appearance and shear resistance. In order to meet the design requirements of 14–15.5 KN tensile load for the notch bolt with an arc-shaped structure, four raw material tensile intervals corresponding to the notch bottom diameters were established by using domestic GH4169 grade C cold-drawn bars.

Development of submarine canyons on the continental slope of the Okinawa Trough with potential origin related to methane seepage

Submarine canyons serve as conduits to transport terrigenous detrital sediment and organic carbon to the deep sea. Herein, we carried out a detailed analysis of the geomorphological and erosional-depositional features of submarine canyons on the middle and southern slopes of the Okinawa Trough based on the established isochronous chronostratigraphic framework. According to sequence stratigraphy and well-seismic calibration technologies, the ages of six stratigraphic boundaries are redetermined, which are aged: Seafloor (0 Ma), TLGM (23kyr B. P.), T0 (1.8 Ma), T10 (6.0 Ma), T12 (11.02 Ma), and T16 (16.12 Ma), respectively. The submarine canyons mainly began to develop during the last glacial maximum (LGM), and some might initiate earlier in the early Pleistocene (<1.8 Ma) and further evolved after the LGM. Along the axial direction, the heads of these shelf-indenting canyons were mostly inherited from the ancient incised valleys developed on the shelf edge during the LGM; and the canyon channels were filled with multi-stage turbidites and mass transport deposits (MTDs). The multi-BSRs (bottom simulating reflectors), arched or imbricated and chaotic or twisty reflections, as well as pipe, notch, and mud volcano structures on seismic profiles indicate widespread gas-bearing fluid migration and methane seepage that is possibly related to gas hydrate dissociation. Besides the sea-level change and tectonic movements, we find that the slope failure (gravity flow) induced by gas hydrate dissociation accompanied by methane seepage during the glacial epoch (mainly the LGM) is a main controlling factor for canyon initiation in the Okinawa Trough. The link between canyon development and methane seepage is confirmed by characteristic seismogeologic expressions, such as the MTDs associated with BSRs, the imbricated, twisty or chaotic seismic reflections inside the MTDs, the liquefaction deformation structures, and the fluid transport pipes. In addition, the notches (maybe pockmarks or seabed depressions) that indicate methane escaping on the canyon sidewalls, and the truncated relationship between the BSRs and canyon channels further indicate that there is a complex relationship between the submarine canyons and the methane seepage associated with gas hydrate. Finally, a coupled model was established to illustrate the four evolutional stages of the submarine canyons, which provide an attractive case of how the submarine canyon dynamically responds to gas hydrate system. Therefore, our new findings are of great significance for understanding the mechanism of the submarine canyon and reconstructing the evolutionary history of gas hydrate modulated by sea-level changes in geological history.

Skyrmion Creation and Annihilation by Electric Current Vorticity

Motivated by the recent experiment done by Yu <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> [X. Z. Yu, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et. al.</i> , Sci. Adv., 6, 25, eaaz9744 (2020)] on magnetic skyrmion creation and annihilation by electric currents in FeGe devices with a notch structure, we examine the interaction between the electric current vorticity near the notch and localized spins, and obtain three effects of the current vorticity on the localized spins. The first one is an effective Zeeman field induced by the current vorticity. This effective Zeeman field is responsible for skyrmion creation. The second effect is a vorticity-induced Dzyaloshinskii–Moriya (DM) interaction with the direction of the DM vector being parallel to the vorticity direction and is different from the vector of the intrinsic DM interaction. This vorticity-induced DM interaction makes the skyrmions distorted. The third effect is a spin current due to the gradient of the vorticity and the spin current drives the magnetic skyrmions far from the notch. Our theory opens a new path to design the magnetic textures by using structural settings.

Wideband low-profile H-shaped dielectric patch antennas based microwave dielectric ceramics

Dielectric patch antenna (DPA) has been extensively studied in recent years, especially for the application of 5G mobile communication system. In this paper, we proposed a notch structure of H-shaped DPA (HDPA) with wideband low-profile properties but without additional components. Temperature stable 0.65 CaTiO3–0.35 LaAlO3 microwave dielectric ceramic of high permittivity was utilized for fabricating the H-shaped dielectric patch, and the method of leveraging the multi-modal features of DPA was introduced. Further analysis of the antenna structure was accomplished by the simplified theoretical method. As a result, the H-shaped notch is properly ensembled in the dielectric patch to make the higher-order TM121 mode close to the dominant TM101 mode, greatly expanding the broadband of the HDPA. The accuracy of the proposed HDPA element model is evaluated by the commercial full-wave simulator CST Microwave Studio. For demonstration, a prototype of the proposed HDPA element operating in the microwave band (5-GHz) has been realized and measured.

Multiobjective Optimization of IPMSM With FSCW Applying Rotor Notch Design for Torque Performance Improvement

Fractional-slot concentrated-windings (FSCWs) interior permanent magnet (IPM) synchronous machines (IPMSMs) provide several advantages compared with other types of electric machines and have promising applications in electric vehicles (EVs). Minimizing the cogging torque and torque ripple of this type of motors is essential for improving output torque and driving stability. This article proposes a method for optimizing the torque performance of IPMSM with single-layer FSCW. At first, the theoretical analysis of cogging torque and torque ripple is conducted as the research basis for the optimization. The key point of this method is to describe the structure of the rotor notch as determined by seven design parameters. Then, the response surface methodology (RSM) is adopted to analyze the relationships between torque performance and design parameters. For the multiobjective optimization process, the seagull optimization algorithm (SOA) is introduced to obtain the optimal solution. After the optimization, the torque ripple of the motor achieves a significant reduction and the output torque is also improved. The advantages and reliability are compared and analyzed. Finally, a prototype is manufactured to verify the effectiveness of the proposed method.

Research on Fatigue Life Prediction Method of Key Component of Turning Mechanism Based on Improved TCD

The main objective of this paper is to accurately obtain fatigue life prediction for the key components of a turning mechanism using the improved theory of critical distances (TCD). The irregularly shaped rotating arm is the central stressed part of the turning mechanism, which contains notches. It has been found that TCD achieves good results in predicting the fatigue strength or fatigue life of notched components with regular shape but is less commonly used for notched components with irregular shape. Therefore, TCD was improved and applied broadly to predict the fatigue life of an irregularly shaped rotating arm. Firstly, the notch depth and structure net width parameters were introduced into the low-order and low-accuracy classical TCD function to obtain a novel stress function with high computational efficiency and high accuracy, whereas the stress concentration factor was introduced to modify the length of critical distance. Secondly, the improved TCD was used to predict the fatigue strength of notched components with regular shape, and its accuracy was demonstrated by a fatigue experiment. Finally, the improved TCD was applied to predict the fatigue life of an irregularly shaped rotating arm. The deviation between prediction results and experimental results is less than 18%. The results demonstrate that the improved TCD can be applied effectively and accurately to predict the fatigue life of key components of turning mechanisms.

Fast Design of Spoke-Type PM Motor With Auxiliary Notches Based on Lumped-Parameter Magnetic Equivalent Circuit Model and Hybrid Multiobjective Optimizer

The multi-objective design of PM motor is time-consuming. The accuracy complexity of the solver model and the efficiency of the optimizer affect the cycle of electromagnetic design. A fast design method of spoke-type PM motors with auxiliary notches based on lumped-parameter magnetic equivalent circuit (MEC) model and a hybrid multi-objective optimizer (HyMOO) are proposed in this article. The MEC model is established to quickly reflect the influence of design parameters on electromagnetic and torque performance in the account of auxiliary notch structure in the rotor lamination. Meanwhile, an HyMOO is proposed considering the Grey Wolves Optimization (GWO) model, to solve more complex multimode problems involving more parameters. The accuracy and high calculation speed of the proposed MEC are verified in comparison with the FE method. A benchmark test by general distance (GD) and inverted generational distance (IGD) proves the HyMOO with better converge speed and robustness. Based on the MEC model and HyMOO, a fast electromagnetic design is applied for the motor with requirements of 140Nm rated torque and 4.5% torque ripple. The optimal solutions are validated by FE analyses, and the best design are chosen, manufactured as prototype, and tested. Both the FE and experimental analyses verify the reliability of the fast design and the proposed motor.

Zeeman coupling and Dzyaloshinskii-Moriya interaction driven by electric current vorticity

The Dzyaloshinskii-Moriya interaction, i.e., antisymmetric exchange interaction, combined with a Zeeman magnetic field gives rise to various magnetic states such as chiral, helical, and skyrmionic states. This interaction conventionally originates from spin-orbit coupling and thus needs somewhat heavy elements. In contrast, we here show a Dzyaloshinskii-Moriya interaction which is driven by electric current vorticity. We also find that the vorticity acts on localized spins as a Zeeman field, which may explain a recent experiment on current-driven magnetic skyrmion creation and annihilation without an external magnetic field in a device with a notch structure in FeGe. theory explains the control of skyrmion creation and annihilation by current direction and opens different possibilities for studies of magnetic textures by using structural settings.

A compact wide-bandwidth Antipodal Vivaldi Antenna array with suppressed mutual coupling for 5G mm-wave applications

A modified miniaturized Antipodal Vivaldi Antenna (AVA) array with suppressed mutual coupling is proposed for broadband 5G millimeter wave (mm-wave) application. The configuration is constructed by using eight radiating elements with single 1-to-8 power divider networks. By adding several notch structures, printed on the ground plane, the mutual coupling between the array elements are suppressed. Therefore, the radiating system has maximal additional isolation of 35.6 dB, enhanced gain of 13.36 dB, and extended impedance bandwidth of 26.5–29.5 GHz. In order to validate the design of the radiating system, the AVA array configuration is fabricated and measured with an overall dimension of 21.45 × 52.35 × 0.787 mm3. The experimentally validated gain value of the conventional AVA array antenna and modified array antenna is 4.7–8.35 dB and 8.62–12.67, respectively.

The dual-suppression of peak electric field in AlGaN/GaN HEMT with sandwich structure

To improve the power and RF performance of the high electron mobility transistors (HEMTs) based on AlGaN/GaN heterostructure junction, in this paper, a sandwich structure consisting of gate field plate, SiN passivation layer, and notch structure is proposed. The notch structure at the AlGaN barrier layer between the gate and drain is formed by the Inductively Coupled Plasma etching system (ICP), and the notch has a depth of 15 nm. The dual-suppression of the peak electric field contributes to the breakdown voltage of 91 V, which is a 152.8% improvement compared with the conventional HEMT. The decrease of C gd due to increase of distance between the gate electrode and the lower surface of the depletion layer contributes to the cut-off frequency of 24.1 GHz, which is an 8% improvement. Thus, this composite-structure HEMT has a JFOM of 2.2 THz V, it is an 84.6% improvement compared with the conventional gate field plate HEMT. A well suppression of current collapse is also achieved. It has potential in high power and RF applications. • The Sandwich structure manufacturing process is compatible with the conventional process for AlGaN/GaN HEMTs. • The Sandwich structure has a good suppression on the peak electric field, and it can decrease the capacitance between the gate and drain. • The Sandwich structure not only improves the breakdown characteristic but also improves the cut-off frequency characteristics. • The manufacturing process of the notch structure at AlGaN barrier layer does not cause the surface damage.

Design of UWB Antenna Based on Improved Deep Belief Network and Extreme Learning Machine Surrogate Models

In the design of conventional microwave devices, the parameters need to be continuously optimized to meet the desired targets, and the whole process is time-consuming and laborious. As a surrogate model, machine learning is an effective optimization method. However, in the modeling process, the high-dimensional data processing and the complex nonlinear relationship between parameters is a problem to be solved. This paper proposes a deep learning model for designing UWB antennas, which determines the model structure of deep belief network (DBN) by particle swarm algorithm (PSO), and then combines DBN and extreme learning machine (ELM). The proposed model can obtain higher feature learning capability and nonlinear function approximation capability, and has been applied to the optimal design of the whole structure of the fractal antenna and the notch structure of the MIMO antenna, and its S-parameters are well fitted while meeting the requirements of the design targets. The DBN-ELM method obtains the good results when compared with common modeling methods using the same training samples (the root mean square error tested is 11.87% in the fractal antenna and 3.56% in the MIMO antenna). Overall, the proposed DBN-ELM model has higher predictive and generalization capabilities, which can also be used to model more complex antenna structures.