Line Structure Research Articles

Evaluation of direct ink write processing parameter window via machine learning

Direct ink writing 3D printing offers significant advantages for fabricating soft materials. It is a process of forming solid parts from extruded line structures, so the uniformity and stability of the line is critical for successful printing. This study mainly focuses on the process parameter window for achieving uniform and stable printed lines. Four machine learning models (support vector machine, backpropagation neural network, decision tree, and K-nearest neighbour) are built to predict the success of printing. These models exhibited robust predictive capabilities, particularly the backpropagation neural network and support vector machine models, both achieving an accuracy of 0.9091. Utilizing these models, the reasonable processing parameter window and the relationships among printing parameters were analysed. The results indicate that high printing speeds require large extrusion pressure to achieve a high success rate. An increase in nondimensional nozzle height enhances the possibility of successful printing with small pressure and low speed. The predicted processing parameters derived from the machine learning model were applied to print representative structures, showing good prediction performance.

Applying Characteristic Impedance Compensation Cut-Outs to Full Radio Frequency Chains in Multi-Layer Printed Circuit Board Designs.

Modern wireless communication systems are of utmost importance to various sectors such as healthcare, education, the household, and the advancement of emerging technologies like the internet of things, autonomous vehicles, and the enhancement of 5G. Further development and improvement of these systems drives the need for small dimension, high integration and density, and cost-effective electronic devices. Achieving optimal performance in wireless electronic devices involves overcoming engineering challenges related to microstrip line signal integrity. This research addresses the impact of surface mount technology (SMT) component pads on signal integrity, proposing a novel high-frequency microstrip line structure for mitigating impedance discontinuities. The study introduces stepped microstrip lines and explores characteristic impedance compensation techniques. A six-layer printed circuit board (PCB) structure is presented, and the effects of compensation on signal integrity are analyzed using time-domain reflectometry and scattering parameter measurements. The results demonstrate the effectiveness of compensation methods in aligning characteristic impedance with desired values, thereby ensuring improved impedance matching and transmission coefficients. The average over-the-length impedance for the proposed structure with compensation applied was measured to be 52.7 Ω, which is only 1.3 Ω (2.5%) more than that of the reference microstrip. Applying reference plane cut-outs leads to a maximum compensated absolute value of more than 30 Ω to reach the target impedance with a 10% tolerance. This research contributes valuable insights for advancing wireless communication systems and maintaining robustness in high-frequency microstrip transmission lines.

Experimental and Numerical Modeling of the Freeze–thaw Response of U-Shaped Channel Lining on Sulfate Saline Soil Foundation

Under the influence of seasonal freeze-thaw cycles, the concrete lining of channels situated on saline soil foundations is highly vulnerable to an array of deleterious phenomena, such as frost heave, salt expansion, and corrosion. To investigate the synergistic interplay among saline soil substrates, U-shaped channel lining structures, and ambient temperatures during freeze-thaw cycles, a novel Hydraulic-Thermal-Salt-Mechanical (HTSM) model is established in this study. The HTSM model elucidates the migration of moisture and salt solute, ice-water phase transitions, and sodium sulfate crystallization within unsaturated saline soils throughout the freeze-thaw cycles. It considers the variations in volume and pore solution volume before and after the phase transition of sodium sulfate. Temperature and salt frost heaving force measurements obtained from outdoor freeze-thaw cycles are compared with numerical simulation results to validate the efficacy of the HTSM model and investigate the distribution patterns of salt frost heaving force (frost swelling force) along the channel. The results showed that the frost swelling force and depth exhibit a great linear relationship and the maximum stress of the U-shaped channel appears at the bottom of the channel, highlighting the good arching force characteristics of the U-shaped structure which prove that bottom of the channel is also the most prone to fracture. Significantly, the initial water content significantly impacts the frost swelling force—it increases by 4% while the frost swelling force increases by 76%. Comparing the numerical simulation results of temperature variations, moisture changes, and salt-frost heaving forces with the outdoor experimental data, it is evident that the proposed HTSM model effectively simulates the salt-frost heaving patterns observed in U-shaped channel linings.

An Iterative Calculation Method for Internal Forces and Deformation of Curved Tunnel Lining

The accurate prediction of lining forces and deformations is crucial for the design of arched tunnel lining. However, in traditional tunnel structural mechanics methods, the distribution shape of the surrounding rock elastic resistance (SRER), as well as the zero point and maximal point locations of SRER, are not clearly defined. In this paper, an iterative calculation method is proposed based on the gradual convergence of the unitized values of SRER and total displacement (TD) of the lining, and the one-to-one functional relationship between the two in the stability process of the surrounding rock and lining. In this method involves using the initial displacement caused by the pressure of the surrounding rock pressure is used to initiate the iterative process, and iterative calculation is carried out until the errors between the unitized value of SRER and the unitized value of TD of the lining structure meet the error requirements. This enables precise determination of the SRER and TD. In order to verify the effectiveness of the proposed method, a case study is conducted on the tunnel of Lianghe Expressway tunnel in Yunnan province, China. The results showed that when the semi-lining structure is divided into unit blocks and the average error of consistency is required to be less than 1e-3, it takes about 20 iterations are needed to meet the error requirement. Furthermore, the accuracy of the calculated results is verified through site-measuring experiments. This method provides an effective tool for failure analysis of arched tunnel lining structures.

Deep unfolding model‐based for hybrid robust wide band adaptive beamforming

AbstractThe design of arrays capable of receiving wideband signals differs from arrays that can only receive narrowband signals. These arrays must be able to receive signals with an instant bandwidth of several GHz across the entire operating frequency, such as High‐Resolution Radars or Terahertz in 6G communication systems. In these arrays, using a time delay line structure leads to an increase in beamformer coefficients, resulting in high computational complexity. This poses a challenge for beamforming in wideband systems. Additionally, classic Wideband beamformers face other factors, such as poor performance in the presence of input direction of arrival error, array calibration error, and requiring too many snapshots to reach the steady state of the beamformer. Therefore, the robustness of wideband adaptive beamforming using deep unfolding model‐based technique is focused on, which has not been discussed before. The advent of deep unfolding, an innovative technique, amalgamates iterative optimization approaches with elements of neural networks. The aim is to deftly maneuver through various tasks across disciplines such as machine learning, signal and image processing, and telecommunication systems. Also, the network training method is done to become more robust against the mentioned factors. In the proposed structure, the constraints of the previous methods have been evaluated. It is observed to have better performance compared to other classic algorithms. Also, with the investigations of the proposed method with other conventional deep learning methods, it was observed that in some cases the proposed structure performance is equal to the conventional deep learning method and sometimes better.

A Ku/K band dual linearly polarized Reflectarray for earth exploration satellite services

ABSTRACT A novel single-layer dual-band, dual-polarised reflectarray was designed, developed, and tested in this paper. This Reflectarray is a vital component to use, in Earth exploration sensor systems and remote sensing satellites for measuring water levels and cryosphere research. The proposed antenna is employed in dual frequency bands from 12.5–16 GHz to 23.5–26 GHz covering Ku/K bands. The corrugated semi-circular rings enclosed with quad delay line structures attached to the outer ring constitute the Ku band unit cell with periodicity (0.55 λ 0 ) resonating at 14.5 GHz. The K band unit cell with periodicity (0.78 λ 0 ) is constructed similarly to the Ku band unit cell but with a horizontal slot that provides vertical polarisation and resonates at 24.5 GHz. This integrated unit cell configuration results in dual linear, reduced cross-polarisation and allows independent phase optimisation at each frequency band. Phase variation of 770° and 811° at the operating frequencies of 14.5 GHz and 24.5 GHz is achieved by varying the element sizes. A centre-fed RA constructed on a square aperture (12.34 λ 0 ) comprising 23 × 23 elements for each frequency band gives the measured results of 1 dB bandwidth of 24% and 10.2% and peak gain of 28.2 dB and 27.6 dB at Ku/K bands, respectively.

Timely Constructed and Enhanced Lining for Managing Extensive Deformations of Tunnel in Coal Stratum: A Case Study

Background The Sanlian Tunnel case study exemplifies that even after implementing the initial support within the coal stratum, the surrounding rocks exhibited ongoing deformation devoid of stabilization indications. Addressing this issue calls for innovative control technologies that mitigate extensive deformations and redefine safe and sustainable coal stratum tunnel construction. Methods The field experiment was adopted to select the appropriate technical measures to control extensive deformations. Three experiment schemes were developed and applied to the construction. Scheme One was the enhanced initial support structure, and Scheme Two was the combined use of enhanced initial support structure, lengthened sidewall anchor rods and added steel pipe piles. Scheme Three was the “timely constructed and enhanced lining structure” proposed on the basis of Scheme Two, and the secondary lining was applied if the horizontal displacement exceeded 450mm. Then, field observations of displacements and stresses were implemented to evaluate the effectiveness of different experimental schemes in controlling extensive deformations. Results Scheme One and Two cannot control extensive deformations effectively, as the displacement of the initial support continued to increase with no sign of stabilization. Regarding Scheme Three, structural deformation progressively attained a state of stability around 80 days subsequent to the secondary lining construction. Additionally, the stress within the support structure remains stable below the permissible threshold, affirming the secure condition. Conclusion Emanating from the field monitoring results, it is evident that the suggested “timely constructed and enhanced lining structure” scheme control technology holds substantial promise for practical implementation in engineering scenarios.

Research on Image Stitching Algorithm Based on Point-Line Consistency and Local Edge Feature Constraints.

Image stitching aims to synthesize a wider and more informative whole image, which has been widely used in various fields. This study focuses on improving the accuracy of image mosaic and proposes an image mosaic method based on local edge contour matching constraints. Because the accuracy and quantity of feature matching have a direct influence on the stitching result, it often leads to wrong image warpage model estimation when feature points are difficult to detect and match errors are easy to occur. To address this issue, the geometric invariance is used to expand the number of feature matching points, thus enriching the matching information. Based on Canny edge detection, significant local edge contour features are constructed through operations such as structure separation and edge contour merging to improve the image registration effect. The method also introduces the spatial variation warping method to ensure the local alignment of the overlapping area, maintains the line structure in the image without bending by the constraints of short and long lines, and eliminates the distortion of the non-overlapping area by the global line-guided warping method. The method proposed in this paper is compared with other research through experimental comparisons on multiple datasets, and excellent stitching results are obtained.

Stress state analysis and symmetrical optimization of double-row non-symmetrical arrangement of anchorage slot in concrete lining structure

The role of the anchorage slot is to fix the anchorage and tension anchor rope, which is the weakest link of the concrete lining structure. The stress state of the anchorage slot area in the construction and operation stages of the 2# sand discharge of the Xiaolangdi Project was analyzed by modeling in this paper. The results showed that the stress state of the anchorage slot area was the most complex. The tensile stress was generated in the radial direction of the concrete lining during the construction period, and the circumferential pre-compression stress was unevenly distributed along the thickness direction. During the operation period, when the backfill concrete at the anchor slot and the lining jointly bore the internal water pressure, a tensile stress of 0.89 MPa was generated in the inner anchorage slot area of the lining, which was less than the tensile strength of the concrete itself. Finite element calculation results were compared with the field-measured data, and the results were essentially the same. Finite element analysis software was used to optimize the double-row asymmetric arrangement of the anchorage slots into a single-row symmetrical structure. The results showed that the angle of the complex stress area of the lining is reduced by about 75%. The optimized single-row symmetrical anchorage slot layout was safer, and the pre-stressing distribution was more uniform.

Numerical Investigation into the Dynamic Responses of Floating Photovoltaic Platform and Mooring Line Structures under Freak Waves

Floating photovoltaics (PVs) are progressively constructed in the ocean sea; therefore, the effect that freak waves have on their structural design needs to be considered. This paper developed a dedicated numerical model coupling the floating PV platform and mooring line structures to investigate their dynamic responses under freak waves. A feasible superposition approach is presented to generate freak wave sequences via the combination of transient waves and random waves. A large floating PV platform moored by twenty lines for a water depth of 45 m was designed in detail according to the actually measured ocean environmental and geological conditions. The global time domain analyses of the floating PV mooring structures were implemented to obtain dynamic responses, including PV platform motions and the mooring line configuration and tension under freak waves. A comparison of the response results with those caused by random waves was conducted to illustrate the intuitive evidence of the freak wave effects, which offer a significant reference for the preliminary design of the floating PV platform and mooring line structures.

Numerical Simulation of Mechanical Characteristics and Safety Performance for Pre-Cracked Tunnel Lining with the Extended Finite Element Method

The service performance of tunnel lining is affected by crack properties and development states. In this paper, numerical simulation models were established to investigate the mechanics characteristics and safety performance for lining structures under different cracks based on the extended finite element method (XFEM). Analyze multiple quantitative factors in simulation, including changes in crack location, crack length, and crack distribution range in the lining structure. The axial force and bending moment of the preset cracks in the lining structures were first studied. The maximum safety factor attenuation rate (Dkmax) was proposed to analyze the impact of longitudinal and annular cracks on the safety performance. The axial force at the vault of the lining arch is the most significantly affected by the combined longitudinal cracks at multiple locations. When the length of a longitudinal crack increases from 1 m to 6 m, the axial force value at the crack point decreases by 33.77%, 36.15%, and 11.32%. However, the bending moment value increases by 4.47 times, 2.50 times, and 1.69 times. Under the influence of longitudinal cracks in an “arch crown + arch shoulder”, “arch crown + arch waist”, and “arch crown + arch shoulder + arch waist”, the axial force in the arch vault increased by 21.55%, decreased by 17.52%, and decreased by 13.45%. The distribution pattern of the bending moment under the influence of circumferential cracks shows convexity at the arch shoulder and arch foot, and concavity at the arch waist and side walls. The safety factor scatter curve with longitudinal cracks shows a gradual transition from a “W” shape to a “U” shape. The safety factor curve with circumferential cracks presents an approximately symmetrical wave-shaped distribution.

PAR-4/LKB1 prevents intestinal hyperplasia by restricting endoderm specification in Caenorhabditis elegans embryos.

The kinase PAR-4/LKB1 is a major regulator of intestinal homeostasis, which prevents polyposis in humans. Moreover, its ectopic activation is sufficient to induce polarization and formation of microvilli-like structures in intestinal cell lines. Here, we use Caenorhabditis elegans to examine the role of PAR-4 during intestinal development in vivo. We show that it is not required to establish enterocyte polarity and plays only a minor role in brush border formation. By contrast, par-4 mutants display severe deformations of the intestinal lumen as well as supernumerary intestinal cells, thereby revealing a previously unappreciated function of PAR-4 in preventing intestinal hyperplasia. The presence of supernumerary enterocytes in par-4 mutants is not due to excessive cell proliferation, but rather to the abnormal expression of the intestinal cell fate factors end-1 and elt-2 outside the E lineage. Notably, par-4 mutants also display reduced expression of end-1 and elt-2 inside the E lineage. Our work thereby unveils an essential and dual role of PAR-4, which both restricts intestinal specification to the E lineage and ensures its robust differentiation.

Design of highly sensitive temperature sensor based on photonic band gap structure

In this paper, a novel microstrip resonator technique for temperature sensing is proposed, designed, and implemented using a hybrid planar microstrip line and photonic band gap (PBG) structure. To implement the PBG structure of the microstrip line, a microfluidic channel with periodic form is introduced into the substrate and filled with water. The operation principle of the sensor is based on a frequency shift due to the variation in the center of the band gap, which in turn changes with the variation of the permittivity of water, which relates to the temperature. The different empirical expressions describing the complex permittivity with the resonant frequency were carried out. The proposed sensor is simple in design and low cost, which may be applied in different applications at the industrial.

DKPE-GraphSYN: a drug synergy prediction model based on joint dual kernel density estimation and positional encoding for graph representation.

Introduction: Synergistic medication, a crucial therapeutic strategy in cancer treatment, involves combining multiple drugs to enhance therapeutic effectiveness and mitigate side effects. Current research predominantly employs deep learning models for extracting features from cell line and cancer drug structure data. However, these methods often overlook the intricate nonlinear relationships within the data, neglecting the distribution characteristics and weighted probability densities of gene expression data in multi-dimensional space. It also fails to fully exploit the structural information of cancer drugs and the potential interactions between drug molecules. Methods: To overcome these challenges, we introduce an innovative end-to-end learning model specifically tailored for cancer drugs, named Dual Kernel Density and Positional Encoding (DKPE) for Graph Synergy Representation Network (DKPEGraphSYN). This model is engineered to refine the prediction of drug combination synergy effects in cancer. DKPE-GraphSYN utilizes Dual Kernel Density Estimation and Positional Encoding techniques to effectively capture the weighted probability density and spatial distribution information of gene expression, while exploring the interactions and potential relationships between cancer drug molecules via a graph neural network. Results: Experimental results show that our prediction model achieves significant performance enhancements in forecasting drug synergy effects on a comprehensive cancer drug and cell line synergy dataset, achieving an AUPR of 0.969 and an AUC of 0.976. Discussion: These results confirm our model's superior accuracy in predicting cancer drug combinations, providing a supportive method for clinical medication strategy in cancer.

Imaging Mueller matrix ellipsometry measurements on measuring fields in the micrometre range

An imaging Mueller matrix ellipsometer is used to measure structures in measuring fields in the micrometre range, which are too small for conventional ellipsometry. Line and grid structures are measured and evaluated with the help of numerical simulations using the finite element method to characterize the structure parameters.

A 28‐GHz Vivaldi Array Antenna With Power Divider Structure for Achieving Wide Band and Gain Enhancement

This article presents a planar Vivaldi array antenna based on a power divider structure. A half‐loop defected ground structure (DGS) is performed to decrease the mutual coupling between antennas in the bottom layer of the substrate. The proposed Vivaldi antenna has a 1 × 8 power divided microstrip line structure and performs well in antenna gain and beam directivity. To validate the design, the proposed high‐gain planar Vivaldi array antenna was manufactured, and the measured results were very similar to the simulated one. The size of the proposed antenna is 67 × 44 mm2, the application band is 25–27.3 GHz, and the measured peak gain is 12.6 dBi. The antenna is simulated with an electromagnetic power density (PD) of 28.5 W/m2 at 1 cm2 and 7.27 W/m2 at 4 cm2, which are in compliance with the FCC regulations. Therefore, this antenna is suitable for wearable devices and is applied to n257, n258, and n261.

The impact of the degree of automation on the configuration of a car battery assembly line

This paper presents the concept of an automotive battery assembly line. The line includes in its structure fully and semi-automated assembly sockets, as well as manual assembly sockets. The transport between the sockets is carried out using an AGV autonomous trolley system. The selection of the assembly process execution method was based on an analysis of the technical feasibility of the process as well as an analysis of the occupation time of individual assembly stations. The resulting line structure indicates to what extent the automation of the assembly process contributes to a change in material flow and influences the way the process is carried out, including a variety of technical means used. The paper presents an analysis of the use of particular workstations. This analysis was used to optimise the flow of the component assembly line. Maximum utilisation of the resources involved in the production process was used as a criterion for optimisation.

Design of Bandpass Filtering Power Amplifier Based on Coupled Microstrip Line Structure

Design of Bandpass Filtering Power Amplifier Based on Coupled Microstrip Line Structure

Switchable and high-efficiency phase-locking of S-band magnetrons with coaxial line

We propose a coaxial line structure for phase-locking between magnetrons in the S-band for the first time. In this structure, two magnetrons operating in the π-mode are tightly coupled by the coaxial line. The design of a coaxial line structure, independent of physical dimensions, solves the problem of a ridge waveguide or rectangular waveguide being unsuitable for phase-locking in the compact S-band magnetron, as proposed by previous researchers. In addition, the phase relationship of the magnetron output signal in the phase-locked state can be switched between 0 and the π phase difference without changing the length of the coaxial line. Therefore, this design widens the frequency range used by mutual coupling phase-locked technology and allows switching of the phase relationship in an output signal without the need for additional equipment or physical space. After design simulation, two magnetrons achieved high-efficiency phase locking at a frequency of 2.415 GHz, with a phase-locked efficiency of 99.8%.

Effect of Furnace Lining Structure on the Flow Field in the 35t Top-blowing Converter Steelmaking Process

Effect of Furnace Lining Structure on the Flow Field in the 35t Top-blowing Converter Steelmaking Process