This paper introduces the complex image concept, and uses the method to analyze multi conductor coplanar waveguides. The method of spectral domain Green's function for modeling point charge and line charge struct...This paper introduces the complex image concept, and uses the method to analyze multi conductor coplanar waveguides. The method of spectral domain Green's function for modeling point charge and line charge structures is studied, in which Chebyshev polynomials are used as basis functions to solve the integral equation by the Galerkin's method. It is believed that the complex method has the features of accuracy and rapid convergence, and it is possible to make the technique useful as CAD tool for coplanar waveguide design.展开更多
Analog reservoir computing(ARC)systems offer an energy-efficient platform for temporal information processing.However,their physical implementation typically requires disparate materials and device architectures for d...Analog reservoir computing(ARC)systems offer an energy-efficient platform for temporal information processing.However,their physical implementation typically requires disparate materials and device architectures for different system components,leading to complicated fabrication processes and increased system complexity.In this work,we present a coplanar floating-gate antiferroelectric field-effect transistor(FG AFeFET)that unifies multiple neural functionalities within a single device,enabling the physical implementation of a complete ARC system.By combining a coplanar layout design with an area ratio engineering strategy,we achieve tunable device behaviors,including volatile responses for artificial neuron emulation,nonvolatile states for synaptic functions,and fading memory dynamics for reservoir operations.The mechanisms underlying these functionalities and their operating mechanism are systematically elucidated using load line analysis and energy band diagrams.Leveraging these insights,we demonstrate an all-in-one ARC system based on the unified coplanar FG AFeFET architecture,which achieves recognition accuracies of 95.6%and 83.4%on the MNIST and Fashion-MNIST datasets,respectively.These findings highlight the potential of coplanar FG AFeFETs to deliver area-efficient,design-flexible neuromorphic hardware for next-generation computing systems.展开更多
Inner flange and side wrinkling often occur in rotary-draw bending process of rectangular aluminum alloy wave-guide tubes, and the distribution and magnitude of wrinkling is related to geometrical parameters of the tu...Inner flange and side wrinkling often occur in rotary-draw bending process of rectangular aluminum alloy wave-guide tubes, and the distribution and magnitude of wrinkling is related to geometrical parameters of the tubes. In order to study the effects of geometrical parameters on wrinkling of rectangular wave-guide tubes, a 3D-FE model for rotary-draw bending processes of thin-walled rectangular aluminum alloy wave-guide tubes was built based on the platform of ABA-QUS/Explicit, and its reliability was validated by experiments. Simulation and analysis of the influence laws of geometrical parameters on the wave heights of inner flange and side wrinkling were then carried out. The results show that inner flange wrinkling is the main wrinkling way to rectan- gular wave-guide tubes in rotary-draw bending processes, but side wrinkling cannot be neglected because side wrinkling is 2/3 of inner flange wrinkling when b and h are smaller. Inner flange and side wrinkling increase with increasing b and h; the influence of b on side wrinkling is larger than that of h, while both b and h affect inner flange wrinkling greatly. Inner flange and side wrinkling decrease with increasing R/h; the influence of h on inner flange and side wrinkling is larger than that of R.展开更多
A theory of the far spatial coherent-suppressed single-peak field distribution of a rectangular wave-guide CO2 laser is presented. The theoretical analysis shows that a rectangular wave-guide laser can have an output ...A theory of the far spatial coherent-suppressed single-peak field distribution of a rectangular wave-guide CO2 laser is presented. The theoretical analysis shows that a rectangular wave-guide laser can have an output intensity distribution in far field similar to that produced from a wave-guide array laser, which is in agreement with the experimental result. A single-peak mode output is obtained within 5 metres. The experimental far-field spread angle in the bigger-Fresnel number direction is 0.63 mrad, compared to the calculated one, 0.6 mrad, and when the length of the laser resonator is changed, a double-peak or multi-peak in far-field distribution of the laser is obtained.展开更多
The donor-acceptor hydrogen bonding strategy has been proposed to enforce coplanar packing of anisotropic π-conjugated units, thereby maximizing the material's achievable birefringence. Herein, employing this str...The donor-acceptor hydrogen bonding strategy has been proposed to enforce coplanar packing of anisotropic π-conjugated units, thereby maximizing the material's achievable birefringence. Herein, employing this strategy, we successfully obtain two highly coplanar birefringent crystals, FAHC_(2)O_(4) and FAH_(2)C_(3)N_(3)S_(3) (FA+: CH5N2, for-mamidinium). FAHC_(2)O_(4) shows a wide bandgap (4.20 eV), while FAH_(2)C_(3)N_(3)S_(3) exhibits a narrower bandgap (2.96 eV) due to the involvement of sulfur atom. Both crystals display notable birefringence in their respective material classes: 0.275@546 nm and 0.504@546 nm, respectively. X-ray crystallography and computational studies attribute the pronounced birefringence to their π-conjugated moieties and their near-coplanar configu-rations. Comparative analysis of FAHC_(2)O_(4) and FAH_(2)C_(3)N_(3)S_(3) further establishes that the hydrogen bond strength directly influences the molecular coplanarity degree. These findings provide new insights for applying the donor-acceptor hydrogen bonding strategy in the rational design of high-performance birefringent materials.展开更多
During the excavation of large-scale rock slopes and deep hard rock engineering,the induced rapid unloading serves as the primary cause of rock mass deformation and failure.The essence of this phenomenon lies in the o...During the excavation of large-scale rock slopes and deep hard rock engineering,the induced rapid unloading serves as the primary cause of rock mass deformation and failure.The essence of this phenomenon lies in the opening-shear failure process triggered by the normal stress unloading of fractured rock mass.In this study,we focus on local-scale rock fracture and conduct direct shear tests under different normal stress unloading rates on five types of non-persistent fractured hard rocks.The aim is to analyze the influence of normal stress unloading rates on the failure modes and shear mechanical characteristics of non-persistent fractured rocks.The results indicate that the normal unloading displacement decreases gradually with increasing normal stress unloading rate,while the influence of normal stress unloading rate on shear displacement is not significant.As the normal stress unloading rate increases,the rocks brittle failure process accelerates,and the degree of rocks damage decreases.Analysis of the stress state on rock fracture surfaces reveals that increasing the normal stress unloading rate enhances the compressive stress on rocks,leading to a transition in the failure mode from shear failure to tensile failure.A negative exponential strength formula was proposed,which effectively fits the relationship between failure normal stress and normal stress unloading rate.The findings enrich the theoretical foundation of unloading rock mechanics and provide theoretical support for disasters prevention and control in rock engineering excavations.展开更多
Three kinds of coplanar waveguides （CPWs） are designed and fabricated on different silicon substrates---common low-resistivity silicon substrate （LRS）, LRS with a 3μm-thick silicon oxide interlayer, and high-resi...Three kinds of coplanar waveguides （CPWs） are designed and fabricated on different silicon substrates---common low-resistivity silicon substrate （LRS）, LRS with a 3μm-thick silicon oxide interlayer, and high-resistivity silicon （HRS） substrate. The results show that the microwave loss of a CPW on LRS is too high to be used, but it can be greatly reduced by adding a thick interlayer of silicon oxide between the CPW transmission lines and the LRS.A CPW directly on HRS shows a loss lower than 2dB/cm in the range of 0-26GHz and the process is simple,so HRS is a more suitable CPW substrate.展开更多
In order to broaden the bandwidth of a tapered slot- line antenna （TSA）, a bilateral tapered slot-line antenna （BTSA） with a new feeding structure of coplanar waveguide （CPW） is developed. Based on the fact that...In order to broaden the bandwidth of a tapered slot- line antenna （TSA）, a bilateral tapered slot-line antenna （BTSA） with a new feeding structure of coplanar waveguide （CPW） is developed. Based on the fact that the bandwidth limitation of TSA mainly depends on its feeding structure, an improved CPW-based feed structure etched on the backboard of the BTSA is adopted to perform traveling-wave transition. Both the simulation results and measurement data verify that the proposed feeding structure results in ＂high-pass＂ frequency response for antenna impedance matching. The voltage standing wave ratio （VSWR） is less than 2：1 when the frequency is higher than 3 GHz. The antenna gain exceeds 7 dBi with good radiation patterns when the bandwidth is from 4 to 16 GHz. This ultra wideband （UWB） antenna with a compact size is specially available for the electronic systems of counter-measure and microwave imaging.展开更多
The transient response of two coplanar cracks in a piezoelectric ceramic under antiplane mechanical and inplane electric impacting loads is investigated in the present paper. Laplace and Fourier transforms are used to...The transient response of two coplanar cracks in a piezoelectric ceramic under antiplane mechanical and inplane electric impacting loads is investigated in the present paper. Laplace and Fourier transforms are used to reduce the mixed boundary value problems to Cauchy-type singular integral equations in Laplace transform domain, which are solved numerically. The dynamic stress and electric displacement factors are obtained as the functions of time and geometry parameters. The present study shows that the presence of the dynamic electric field will impede or enhance the propagation of the crack in piezoelectric ceramics at different stages of the dynamic electromechanical load. Moreover, the electromechanical response is greatly affected by the ratio of the space of the cracks and the crack length.展开更多
Purpose: To compare the dosimetric impact of coplanar intensity modulated radiation therapy (IMRT) and non-coplanar IMRT for the esophageal carcinoma. Methods: There are forty-five esophageal carcinoma patients, fifte...Purpose: To compare the dosimetric impact of coplanar intensity modulated radiation therapy (IMRT) and non-coplanar IMRT for the esophageal carcinoma. Methods: There are forty-five esophageal carcinoma patients, fifteen of whom were cervical and upper thoracic (Group 1) and thirty were middle and lower thoracic (Group 2). Gross tumor volume (GTV), clinical target volume (CTV), and organs at risk (OAR) were contoured by the chief physician in the CMS-XiO treatment planning system. For each patient, one coplanar plan and two non-coplanar plans have been created using the same physical objective function. A detailed dose-volume histogram (DVH) comparison among three plans was then carried out in a tabulated format. Results: 1) In Group 1 patients with PTV volume less than 100cc, the mean dose and dose gradient of non-coplanar plan were much better than those in coplanar plan. 2) In Group 2 patients, the conformity index (CI) for coplanar and two non-coplanar plans were 0.69 ± 0.13, 0.41 ± 0.13, and 0.68 ± 0.15, respectively. The V5, V10, V20, and the mean dose to the lung were lower in the non-coplanar plans compared to ones in coplanar plan. However, the non-coplanar plans resulted in an increase in a dose to the heart, but the dose was still within heart toxicity tolerance. Conclusion: For Group 1 patients, the non-coplanar IMRT plan had less dose gradient and better mean dose than the coplanar IMRT plan. For Group 2 patients, the non-coplanar IMRT could the decrease dose to the lung tissue, thus lowering the probability of radiation pneumonia to esophageal cancer patients. The drawback of non-coplanar IMRT is that, even within toxicity tolerance, it could deliver a higher dose to the heart and spinal cord compared to the coplanar plan. Therefore, for patients with cardiology and neurology concern, non-coplanar IMRT should be used with caution.展开更多
We discuss the characterization and modeling of coplanar waveguides （CPW） realized in TSMC 0. 13μm CMOS process. EM-field simulations with momentum are performed to estimate the important parameters of the transmis...We discuss the characterization and modeling of coplanar waveguides （CPW） realized in TSMC 0. 13μm CMOS process. EM-field simulations with momentum are performed to estimate the important parameters of the transmission lines, such as characteristic impedance and propagation loss. Coplanar waveguide libraries are designed with Z values of 30,50,70, and 100Ω. Finally, the propagation constant and the characteristic impedance are measured in a frequency range from 0. 1 to 40GHz with a vector-network analyzer,using the short-open-loadthru （SOLT） de-embedding technique. The distributed parameters of the CPWs are extracted from the measured S-parameters.展开更多
In this paper, the authors present an analytical model for coplanar waveguide on silicon-on-insulator substrate. The four-element topological network and the conformal mapping technique are used to analyse the capacit...In this paper, the authors present an analytical model for coplanar waveguide on silicon-on-insulator substrate. The four-element topological network and the conformal mapping technique are used to analyse the capacitance and the conductance of the sandwich substrate. The validity of the model is verified by the full-wave method and the experimental data. It is found that the inductance, the resistance, the capacitance and the conductance from the analytical model show they are in good agreement with the corresponding values extracted from experimental Sparameter until 10 GHz.展开更多
The skin effect is an electromagnetic phenomenon that makes the current flows only on the surface of the conductors at high frequency. This article is based on the phenomenon to model a structure made in coplanar tech...The skin effect is an electromagnetic phenomenon that makes the current flows only on the surface of the conductors at high frequency. This article is based on the phenomenon to model a structure made in coplanar technology. In reality, these types of structures integrated metal layers of different thickness of copper (9 μm, 18 μm, 35 μm, 70 μm). The neglect of this parameter introduces errors, sometimes significant, in the numerical calculations. This is why an iterative method (FWCIP) based on the wave concept was restated. Validation of results was carried out by comparison with those calculated by Ansoft HFSS software and Agilent ADS Technology. They show a good matching.展开更多
Fluctuated loadings from currents,waves and sea ground motions are observed on offshore steel pipelines,and they will result in small cracks to propagate continuously and cause unexpected damage to offshore/geotechnic...Fluctuated loadings from currents,waves and sea ground motions are observed on offshore steel pipelines,and they will result in small cracks to propagate continuously and cause unexpected damage to offshore/geotechnical infrastructures.In spite of the availability of efficient techniques and high-power computers for solving crack problems,investigations on the fatigue life of offshore pipelines with 3D interacting cracks are still rarely found in open literature.In the current study,systematic numerical investigations are performed on fatigue crack growth behaviours of offshore pipelines containing coplanar and non-coplanar cracks.Extended finite element method(XFEM)is adopted to simulate the fatigue crack growth.The qualitative validations of numerical results are made for certain cases with available experimental results.Parametric studies are conducted to investigate the influences of various important parameters on fatigue crack growth.The results will be helpful to assess the fatigue behaviours of steel pipeline with 3D interacting cracks.展开更多
基金Supported by the National Natural Science Foundation of China!( 6 96 71 0 1 4)bytheMillimeterWaveStateKeyLaboratoryofSou
文摘This paper introduces the complex image concept, and uses the method to analyze multi conductor coplanar waveguides. The method of spectral domain Green's function for modeling point charge and line charge structures is studied, in which Chebyshev polynomials are used as basis functions to solve the integral equation by the Galerkin's method. It is believed that the complex method has the features of accuracy and rapid convergence, and it is possible to make the technique useful as CAD tool for coplanar waveguide design.
基金supported by the National Research Foundation,Prime Minister's Office,Singapore,under its Competitive Research Program(NRF-CRP24-2020-0002)。
文摘Analog reservoir computing(ARC)systems offer an energy-efficient platform for temporal information processing.However,their physical implementation typically requires disparate materials and device architectures for different system components,leading to complicated fabrication processes and increased system complexity.In this work,we present a coplanar floating-gate antiferroelectric field-effect transistor(FG AFeFET)that unifies multiple neural functionalities within a single device,enabling the physical implementation of a complete ARC system.By combining a coplanar layout design with an area ratio engineering strategy,we achieve tunable device behaviors,including volatile responses for artificial neuron emulation,nonvolatile states for synaptic functions,and fading memory dynamics for reservoir operations.The mechanisms underlying these functionalities and their operating mechanism are systematically elucidated using load line analysis and energy band diagrams.Leveraging these insights,we demonstrate an all-in-one ARC system based on the unified coplanar FG AFeFET architecture,which achieves recognition accuracies of 95.6%and 83.4%on the MNIST and Fashion-MNIST datasets,respectively.These findings highlight the potential of coplanar FG AFeFETs to deliver area-efficient,design-flexible neuromorphic hardware for next-generation computing systems.
基金financial support of the National Natural Science Foundation of China (No. 50975235 and 50575184)the 111 Project(B08040)
文摘Inner flange and side wrinkling often occur in rotary-draw bending process of rectangular aluminum alloy wave-guide tubes, and the distribution and magnitude of wrinkling is related to geometrical parameters of the tubes. In order to study the effects of geometrical parameters on wrinkling of rectangular wave-guide tubes, a 3D-FE model for rotary-draw bending processes of thin-walled rectangular aluminum alloy wave-guide tubes was built based on the platform of ABA-QUS/Explicit, and its reliability was validated by experiments. Simulation and analysis of the influence laws of geometrical parameters on the wave heights of inner flange and side wrinkling were then carried out. The results show that inner flange wrinkling is the main wrinkling way to rectan- gular wave-guide tubes in rotary-draw bending processes, but side wrinkling cannot be neglected because side wrinkling is 2/3 of inner flange wrinkling when b and h are smaller. Inner flange and side wrinkling increase with increasing b and h; the influence of b on side wrinkling is larger than that of h, while both b and h affect inner flange wrinkling greatly. Inner flange and side wrinkling decrease with increasing R/h; the influence of h on inner flange and side wrinkling is larger than that of R.
文摘A theory of the far spatial coherent-suppressed single-peak field distribution of a rectangular wave-guide CO2 laser is presented. The theoretical analysis shows that a rectangular wave-guide laser can have an output intensity distribution in far field similar to that produced from a wave-guide array laser, which is in agreement with the experimental result. A single-peak mode output is obtained within 5 metres. The experimental far-field spread angle in the bigger-Fresnel number direction is 0.63 mrad, compared to the calculated one, 0.6 mrad, and when the length of the laser resonator is changed, a double-peak or multi-peak in far-field distribution of the laser is obtained.
基金the National Natural Science Foundation of China(22193043).
文摘The donor-acceptor hydrogen bonding strategy has been proposed to enforce coplanar packing of anisotropic π-conjugated units, thereby maximizing the material's achievable birefringence. Herein, employing this strategy, we successfully obtain two highly coplanar birefringent crystals, FAHC_(2)O_(4) and FAH_(2)C_(3)N_(3)S_(3) (FA+: CH5N2, for-mamidinium). FAHC_(2)O_(4) shows a wide bandgap (4.20 eV), while FAH_(2)C_(3)N_(3)S_(3) exhibits a narrower bandgap (2.96 eV) due to the involvement of sulfur atom. Both crystals display notable birefringence in their respective material classes: 0.275@546 nm and 0.504@546 nm, respectively. X-ray crystallography and computational studies attribute the pronounced birefringence to their π-conjugated moieties and their near-coplanar configu-rations. Comparative analysis of FAHC_(2)O_(4) and FAH_(2)C_(3)N_(3)S_(3) further establishes that the hydrogen bond strength directly influences the molecular coplanarity degree. These findings provide new insights for applying the donor-acceptor hydrogen bonding strategy in the rational design of high-performance birefringent materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.42372326 and 42090054)supported by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(SKLGP2023Z015).
文摘During the excavation of large-scale rock slopes and deep hard rock engineering,the induced rapid unloading serves as the primary cause of rock mass deformation and failure.The essence of this phenomenon lies in the opening-shear failure process triggered by the normal stress unloading of fractured rock mass.In this study,we focus on local-scale rock fracture and conduct direct shear tests under different normal stress unloading rates on five types of non-persistent fractured hard rocks.The aim is to analyze the influence of normal stress unloading rates on the failure modes and shear mechanical characteristics of non-persistent fractured rocks.The results indicate that the normal unloading displacement decreases gradually with increasing normal stress unloading rate,while the influence of normal stress unloading rate on shear displacement is not significant.As the normal stress unloading rate increases,the rocks brittle failure process accelerates,and the degree of rocks damage decreases.Analysis of the stress state on rock fracture surfaces reveals that increasing the normal stress unloading rate enhances the compressive stress on rocks,leading to a transition in the failure mode from shear failure to tensile failure.A negative exponential strength formula was proposed,which effectively fits the relationship between failure normal stress and normal stress unloading rate.The findings enrich the theoretical foundation of unloading rock mechanics and provide theoretical support for disasters prevention and control in rock engineering excavations.
文摘Three kinds of coplanar waveguides （CPWs） are designed and fabricated on different silicon substrates---common low-resistivity silicon substrate （LRS）, LRS with a 3μm-thick silicon oxide interlayer, and high-resistivity silicon （HRS） substrate. The results show that the microwave loss of a CPW on LRS is too high to be used, but it can be greatly reduced by adding a thick interlayer of silicon oxide between the CPW transmission lines and the LRS.A CPW directly on HRS shows a loss lower than 2dB/cm in the range of 0-26GHz and the process is simple,so HRS is a more suitable CPW substrate.
基金The National High Technology Research and Development Program of China(863 Program)(No.2007AA01Z264)
文摘In order to broaden the bandwidth of a tapered slot- line antenna （TSA）, a bilateral tapered slot-line antenna （BTSA） with a new feeding structure of coplanar waveguide （CPW） is developed. Based on the fact that the bandwidth limitation of TSA mainly depends on its feeding structure, an improved CPW-based feed structure etched on the backboard of the BTSA is adopted to perform traveling-wave transition. Both the simulation results and measurement data verify that the proposed feeding structure results in ＂high-pass＂ frequency response for antenna impedance matching. The voltage standing wave ratio （VSWR） is less than 2：1 when the frequency is higher than 3 GHz. The antenna gain exceeds 7 dBi with good radiation patterns when the bandwidth is from 4 to 16 GHz. This ultra wideband （UWB） antenna with a compact size is specially available for the electronic systems of counter-measure and microwave imaging.
文摘The transient response of two coplanar cracks in a piezoelectric ceramic under antiplane mechanical and inplane electric impacting loads is investigated in the present paper. Laplace and Fourier transforms are used to reduce the mixed boundary value problems to Cauchy-type singular integral equations in Laplace transform domain, which are solved numerically. The dynamic stress and electric displacement factors are obtained as the functions of time and geometry parameters. The present study shows that the presence of the dynamic electric field will impede or enhance the propagation of the crack in piezoelectric ceramics at different stages of the dynamic electromechanical load. Moreover, the electromechanical response is greatly affected by the ratio of the space of the cracks and the crack length.
文摘Purpose: To compare the dosimetric impact of coplanar intensity modulated radiation therapy (IMRT) and non-coplanar IMRT for the esophageal carcinoma. Methods: There are forty-five esophageal carcinoma patients, fifteen of whom were cervical and upper thoracic (Group 1) and thirty were middle and lower thoracic (Group 2). Gross tumor volume (GTV), clinical target volume (CTV), and organs at risk (OAR) were contoured by the chief physician in the CMS-XiO treatment planning system. For each patient, one coplanar plan and two non-coplanar plans have been created using the same physical objective function. A detailed dose-volume histogram (DVH) comparison among three plans was then carried out in a tabulated format. Results: 1) In Group 1 patients with PTV volume less than 100cc, the mean dose and dose gradient of non-coplanar plan were much better than those in coplanar plan. 2) In Group 2 patients, the conformity index (CI) for coplanar and two non-coplanar plans were 0.69 ± 0.13, 0.41 ± 0.13, and 0.68 ± 0.15, respectively. The V5, V10, V20, and the mean dose to the lung were lower in the non-coplanar plans compared to ones in coplanar plan. However, the non-coplanar plans resulted in an increase in a dose to the heart, but the dose was still within heart toxicity tolerance. Conclusion: For Group 1 patients, the non-coplanar IMRT plan had less dose gradient and better mean dose than the coplanar IMRT plan. For Group 2 patients, the non-coplanar IMRT could the decrease dose to the lung tissue, thus lowering the probability of radiation pneumonia to esophageal cancer patients. The drawback of non-coplanar IMRT is that, even within toxicity tolerance, it could deliver a higher dose to the heart and spinal cord compared to the coplanar plan. Therefore, for patients with cardiology and neurology concern, non-coplanar IMRT should be used with caution.
文摘We discuss the characterization and modeling of coplanar waveguides （CPW） realized in TSMC 0. 13μm CMOS process. EM-field simulations with momentum are performed to estimate the important parameters of the transmission lines, such as characteristic impedance and propagation loss. Coplanar waveguide libraries are designed with Z values of 30,50,70, and 100Ω. Finally, the propagation constant and the characteristic impedance are measured in a frequency range from 0. 1 to 40GHz with a vector-network analyzer,using the short-open-loadthru （SOLT） de-embedding technique. The distributed parameters of the CPWs are extracted from the measured S-parameters.
基金Project supported by the National Natural Science Foundation of China(Grant No.10775166)the Zhejiang Provincial Science Technology Foundation,China(Grant No.2008C31002)
文摘In this paper, the authors present an analytical model for coplanar waveguide on silicon-on-insulator substrate. The four-element topological network and the conformal mapping technique are used to analyse the capacitance and the conductance of the sandwich substrate. The validity of the model is verified by the full-wave method and the experimental data. It is found that the inductance, the resistance, the capacitance and the conductance from the analytical model show they are in good agreement with the corresponding values extracted from experimental Sparameter until 10 GHz.
文摘The skin effect is an electromagnetic phenomenon that makes the current flows only on the surface of the conductors at high frequency. This article is based on the phenomenon to model a structure made in coplanar technology. In reality, these types of structures integrated metal layers of different thickness of copper (9 μm, 18 μm, 35 μm, 70 μm). The neglect of this parameter introduces errors, sometimes significant, in the numerical calculations. This is why an iterative method (FWCIP) based on the wave concept was restated. Validation of results was carried out by comparison with those calculated by Ansoft HFSS software and Agilent ADS Technology. They show a good matching.
基金The authors would like to acknowledge the financial support for this project under Nanyang Technological University,Singapore’s Academic Research Fund(AcRF)Tier 1 Grant No.RG 168/16.
文摘Fluctuated loadings from currents,waves and sea ground motions are observed on offshore steel pipelines,and they will result in small cracks to propagate continuously and cause unexpected damage to offshore/geotechnical infrastructures.In spite of the availability of efficient techniques and high-power computers for solving crack problems,investigations on the fatigue life of offshore pipelines with 3D interacting cracks are still rarely found in open literature.In the current study,systematic numerical investigations are performed on fatigue crack growth behaviours of offshore pipelines containing coplanar and non-coplanar cracks.Extended finite element method(XFEM)is adopted to simulate the fatigue crack growth.The qualitative validations of numerical results are made for certain cases with available experimental results.Parametric studies are conducted to investigate the influences of various important parameters on fatigue crack growth.The results will be helpful to assess the fatigue behaviours of steel pipeline with 3D interacting cracks.
