The surge arrester with excellent protection characteristics would decrease the overvoltage level ap- plied on the power apparatus to reduce their insulation levels and manufacturing bottleneck. The arrester for the 1...The surge arrester with excellent protection characteristics would decrease the overvoltage level ap- plied on the power apparatus to reduce their insulation levels and manufacturing bottleneck. The arrester for the 1000-kV ultra-high voltage ac power transmission system is designed as tank-type structure. The field-circuit combination numerical method combining the three-dimensional finite element method with circuit is proposed to analyze the potential distribution of GIS arrester. By comparing several design schemes, the most effective method to improve the potential distribution along the varistor column is to increase the voltage gradient of the ZnO varistor. Synthesizing several influential factors, the suitable voltage gradient of ZnO varistor should be controlled to 435 V/mm, and the resulted nonuniform degree of the potential distribution along the varistor column inside the GIS arrester would be controlled smaller than 10%. The result in this paper provides the fundamental technical index for the study of the high voltage gradient ZnO varistors.展开更多
The 3-D complex turbulent flow fields in a plunge pool with arciform bottom are simulated by using the k-Ε model in body-fitted coordinates. The calculated results reveal the flow characteristics in the arciform plun...The 3-D complex turbulent flow fields in a plunge pool with arciform bottom are simulated by using the k-Ε model in body-fitted coordinates. The calculated results reveal the flow characteristics in the arciform plunge pool under the different flood discharge conditions, which can not be easily obtained in the physical model test because the measurement of the complex velocity is very difficult. The calculated flow fields are helpful to understand the hydraulic characteristics of plunge pool deeply. The calculated and the measured pressure distributions on the pool bottom are compared and in good agreement.展开更多
Effective features are essential for fault diagnosis.Due to the faint characteristics of a single line-to-ground(SLG)fault,fault line detection has become a challenge in resonant grounding distribution systems.This pa...Effective features are essential for fault diagnosis.Due to the faint characteristics of a single line-to-ground(SLG)fault,fault line detection has become a challenge in resonant grounding distribution systems.This paper proposes a novel fault line detection method using waveform fusion and one-dimensional convolutional neural networks(1-D CNN).After an SLG fault occurs,the first-half waves of zero-sequence currents are collected and superimposed with each other to achieve waveform fusion.The compelling feature of fused waveforms is extracted by 1-D CNN to determine whether the fused waveform source contains the fault line.Then,the 1-D CNN output is used to update the value of the counter in order to identify the fault line.Given the lack of fault data in existing distribution systems,the proposed method only needs a small quantity of data for model training and fault line detection.In addition,the proposed method owns fault-tolerant performance.Even if a few samples are misjudged,the fault line can still be detected correctly based on the full output results of 1-D CNN.Experimental results verified that the proposed method can work effectively under various fault conditions.展开更多
Nasal drug delivery efficiency is highly dependent on the position in which the drug is deposited in the nasal cavity.However,no reliable method is currently available to assess its impact on delivery performance.In t...Nasal drug delivery efficiency is highly dependent on the position in which the drug is deposited in the nasal cavity.However,no reliable method is currently available to assess its impact on delivery performance.In this study,a biomimetic nasal model based on three-dimensional(3D)reconstruction and three-dimensional printing(3DP)technology was developed for visualizing the deposition of drug powders in the nasal cavity.The results showed significant differences in cavity area and volume and powder distribution in the anterior part of the biomimetic nasal model of Chinese males and females.The nasal cavity model was modified with dimethicone and validated to be suitable for the deposition test.The experimental device produced the most satisfactory results with five spray times.Furthermore,particle sizes and spray angles were found to significantly affect the experimental device’s performance and alter drug distribution,respectively.Additionally,mometasone furoate(MF)nasal spray(NS)distribution patterns were investigated in a goat nasal cavity model and three male goat noses,confirming the in vitro and in vivo correlation.In conclusion,the developed human nasal structure biomimetic device has the potential to be a valuable tool for assessing nasal drug delivery system deposition and distribution.展开更多
提出了研究光学镜头猫眼效应的物理光学传输分析方法。该方法以ZEMAX光学设计软件建立的光学镜头模型为基础，采用动态数据交换技术（dynamic data exchange，DDE）获取镜头结构参数；以Collins衍射积分公式为基础，结合矩阵光学理论以...提出了研究光学镜头猫眼效应的物理光学传输分析方法。该方法以ZEMAX光学设计软件建立的光学镜头模型为基础，采用动态数据交换技术（dynamic data exchange，DDE）获取镜头结构参数；以Collins衍射积分公式为基础，结合矩阵光学理论以及将硬边光阑窗口函数展开为有限个复高斯函数之和的方法，进一步推导了高斯光束通过具有基本结构参数的光学镜头后并返回的一般解析传输公式。结果表明，利用该方法仿真得出的猫眼效应反射光在反向传输过程中的空间分布与实验所得极为相似，证明了应用该物理光学传输分析法研究猫眼效应的科学性。展开更多
The sea surface wind field is an important physical parameter in oceanography and meteorology.With the continuous refinement of numerical weather prediction,air-sea interface materials,energy exchange,and other studie...The sea surface wind field is an important physical parameter in oceanography and meteorology.With the continuous refinement of numerical weather prediction,air-sea interface materials,energy exchange,and other studies,three-dimensional(3D)wind field distribution at local locations on the sea surface must be measured accurately.The current in-situ observation of sea surface wind parameters is mainly achieved through the installation of wind sensors on ocean data buoys.However,the results obtained from this single-point measurement method cannot reflect wind field distribution in a vertical direction above the sea surface.Thus,the present paper proposes a theoretical framework for the optimal inversion of the 3D wind field structure variation in the area where the buoy is located.The variation analysis method is first used to reconstruct the wind field distribution at different heights of the buoy,after which theoretical analysis verification and numerical simulation experiments are conducted.The results indicate that the use of variational methods to reconstruct 3D wind fields is significantly effective in eliminating disturbance errors in observations,which also verifies the correctness of the theoretical analysis of this method.The findings of this article can provide a reference for the layout optimization design of wind measuring instruments in buoy observation systems and also provide theoretical guidance for the design of new observation buoys in the future.展开更多
The morphological evolution and coarsening kinetics ofγ'precipitates in a Re-containing Ni-based single crystal superalloy were investigated during isothermal aging at 900,950 and 1000℃.After heat treatment,well...The morphological evolution and coarsening kinetics ofγ'precipitates in a Re-containing Ni-based single crystal superalloy were investigated during isothermal aging at 900,950 and 1000℃.After heat treatment,well-defined cuboidalγ'precipitates with low misfit was obtained within the experimental alloy.Then coarsening rate constants and particle size distribution(PSD)ofγ'phases were calculated and specified based on the measured precipitate sizes for va rying periods of aging times from 100 to 2000 h.After aging for 2000 h,γ'precipitates maintained cubical shape at 900℃,while exhibited sphere at 950 and 1000℃.Coarsening models based on diffusion-controlled process with a functional relationship of r^(3) vs.t(classic Lifshitz-Slyozov-Wagner coarsening model)and interface-controlled model with a function of r^(2) vs.t(trans-interface diffusion-controlled coarsening model)were investigated to fit between the experimental results and theoretical analysis.It was found that Re as the slowest diffusing solute in the alloy constituted the rate-limited step for coarsening based on LSW model,while the process limiting coarsening as governed by an interface diffusion process could possibly be related to the Al diffusion through theγ/γ'interface.The PSDs and coarsening exponent were discussed by comparing the experimental data with predictions of LSW and TIDC models.Finally,coarsening mechanism could be divided into four regimes:(i)coarsening by diffusion-controlled;(ii)coarsening by diffusion and interface cocontrolled;(iii)coarsening by interface-controlled;(iv)coarsening by interface-controlled accompanied withγ'coalescence.展开更多
Al and Mg alloy high pressure die castings(HPDC)are increasingly used in automotive industries.The microstructures in the castings have decisive effect on the casting mechanical properties,in which the microstructure ...Al and Mg alloy high pressure die castings(HPDC)are increasingly used in automotive industries.The microstructures in the castings have decisive effect on the casting mechanical properties,in which the microstructure characteristics are fundamental for the investigation of the microstructure-property relation.During the past decade,the microstructure characteristics of HPDC Al and Mg alloys,especially micro-pores andα-Fe,have been investigated from two-dimensional(2D)to threedimensional with X-ray micro-computed tomography(μ-CT).This paper provides an overview of the current understanding regarding the 3D characteristics and formation mechanisms of microstructures in HPDC alloys,their spatial distributions,and the impact on mechanical properties.Additionally,it outlines future research directions for the formation and control of heterogeneous microstructures in HPDC alloys.展开更多
基金Supported by the National Nature Science Foundation of China (Grant Nos.50425721,5073001)the 11th Five-year National S&T Supporting Plan (Grant No.2006BAA02A16)
文摘The surge arrester with excellent protection characteristics would decrease the overvoltage level ap- plied on the power apparatus to reduce their insulation levels and manufacturing bottleneck. The arrester for the 1000-kV ultra-high voltage ac power transmission system is designed as tank-type structure. The field-circuit combination numerical method combining the three-dimensional finite element method with circuit is proposed to analyze the potential distribution of GIS arrester. By comparing several design schemes, the most effective method to improve the potential distribution along the varistor column is to increase the voltage gradient of the ZnO varistor. Synthesizing several influential factors, the suitable voltage gradient of ZnO varistor should be controlled to 435 V/mm, and the resulted nonuniform degree of the potential distribution along the varistor column inside the GIS arrester would be controlled smaller than 10%. The result in this paper provides the fundamental technical index for the study of the high voltage gradient ZnO varistors.
文摘The 3-D complex turbulent flow fields in a plunge pool with arciform bottom are simulated by using the k-Ε model in body-fitted coordinates. The calculated results reveal the flow characteristics in the arciform plunge pool under the different flood discharge conditions, which can not be easily obtained in the physical model test because the measurement of the complex velocity is very difficult. The calculated flow fields are helpful to understand the hydraulic characteristics of plunge pool deeply. The calculated and the measured pressure distributions on the pool bottom are compared and in good agreement.
基金supported by the National Natural Science Foundation of China through the Project of Research of Flexible and Adaptive Arc-Suppression Method for Single-Phase Grounding Fault in Distribution Networks(No.51677030).
文摘Effective features are essential for fault diagnosis.Due to the faint characteristics of a single line-to-ground(SLG)fault,fault line detection has become a challenge in resonant grounding distribution systems.This paper proposes a novel fault line detection method using waveform fusion and one-dimensional convolutional neural networks(1-D CNN).After an SLG fault occurs,the first-half waves of zero-sequence currents are collected and superimposed with each other to achieve waveform fusion.The compelling feature of fused waveforms is extracted by 1-D CNN to determine whether the fused waveform source contains the fault line.Then,the 1-D CNN output is used to update the value of the counter in order to identify the fault line.Given the lack of fault data in existing distribution systems,the proposed method only needs a small quantity of data for model training and fault line detection.In addition,the proposed method owns fault-tolerant performance.Even if a few samples are misjudged,the fault line can still be detected correctly based on the full output results of 1-D CNN.Experimental results verified that the proposed method can work effectively under various fault conditions.
基金This research was funded by the Key Program for International Science and Technology Cooperation Projects of China(No.2020YFE0201700)the Innovation Leading Talents Short-term Program of Jiangxi Province,China(No.1262000102)Shanghai Science and Technology Plan(No.21DZ2260400,China).
文摘Nasal drug delivery efficiency is highly dependent on the position in which the drug is deposited in the nasal cavity.However,no reliable method is currently available to assess its impact on delivery performance.In this study,a biomimetic nasal model based on three-dimensional(3D)reconstruction and three-dimensional printing(3DP)technology was developed for visualizing the deposition of drug powders in the nasal cavity.The results showed significant differences in cavity area and volume and powder distribution in the anterior part of the biomimetic nasal model of Chinese males and females.The nasal cavity model was modified with dimethicone and validated to be suitable for the deposition test.The experimental device produced the most satisfactory results with five spray times.Furthermore,particle sizes and spray angles were found to significantly affect the experimental device’s performance and alter drug distribution,respectively.Additionally,mometasone furoate(MF)nasal spray(NS)distribution patterns were investigated in a goat nasal cavity model and three male goat noses,confirming the in vitro and in vivo correlation.In conclusion,the developed human nasal structure biomimetic device has the potential to be a valuable tool for assessing nasal drug delivery system deposition and distribution.
文摘提出了研究光学镜头猫眼效应的物理光学传输分析方法。该方法以ZEMAX光学设计软件建立的光学镜头模型为基础，采用动态数据交换技术（dynamic data exchange，DDE）获取镜头结构参数；以Collins衍射积分公式为基础，结合矩阵光学理论以及将硬边光阑窗口函数展开为有限个复高斯函数之和的方法，进一步推导了高斯光束通过具有基本结构参数的光学镜头后并返回的一般解析传输公式。结果表明，利用该方法仿真得出的猫眼效应反射光在反向传输过程中的空间分布与实验所得极为相似，证明了应用该物理光学传输分析法研究猫眼效应的科学性。
基金supported by the Key R&D Program of Shandong Province, China (No. 2023ZLYS01)the National Natural Science Foundation of China (Nos. 91730304 and 41575026)+3 种基金the National Key Research and Development Plan Project (No. 2022 YFC3104200)the Major Innovation Special Project of Qilu University of Technology (Shandong Academy of Sciences) Science Education Industry Integration Pilot Project (No. 2023HYZX01)the ‘Taishan Scholars’ Construction Projectthe Special funds of Laoshan Laboratory
文摘The sea surface wind field is an important physical parameter in oceanography and meteorology.With the continuous refinement of numerical weather prediction,air-sea interface materials,energy exchange,and other studies,three-dimensional(3D)wind field distribution at local locations on the sea surface must be measured accurately.The current in-situ observation of sea surface wind parameters is mainly achieved through the installation of wind sensors on ocean data buoys.However,the results obtained from this single-point measurement method cannot reflect wind field distribution in a vertical direction above the sea surface.Thus,the present paper proposes a theoretical framework for the optimal inversion of the 3D wind field structure variation in the area where the buoy is located.The variation analysis method is first used to reconstruct the wind field distribution at different heights of the buoy,after which theoretical analysis verification and numerical simulation experiments are conducted.The results indicate that the use of variational methods to reconstruct 3D wind fields is significantly effective in eliminating disturbance errors in observations,which also verifies the correctness of the theoretical analysis of this method.The findings of this article can provide a reference for the layout optimization design of wind measuring instruments in buoy observation systems and also provide theoretical guidance for the design of new observation buoys in the future.
基金the financial support by the National Natural Science Foundation of China(51631008)the National Key Research and Development Program of China(No.2016YFB0701400)+1 种基金Natural Science Foundation of Shaanxi Province 2020JM-122the National High Technology Research and Development Program of China(No.2012AA03A511)。
文摘The morphological evolution and coarsening kinetics ofγ'precipitates in a Re-containing Ni-based single crystal superalloy were investigated during isothermal aging at 900,950 and 1000℃.After heat treatment,well-defined cuboidalγ'precipitates with low misfit was obtained within the experimental alloy.Then coarsening rate constants and particle size distribution(PSD)ofγ'phases were calculated and specified based on the measured precipitate sizes for va rying periods of aging times from 100 to 2000 h.After aging for 2000 h,γ'precipitates maintained cubical shape at 900℃,while exhibited sphere at 950 and 1000℃.Coarsening models based on diffusion-controlled process with a functional relationship of r^(3) vs.t(classic Lifshitz-Slyozov-Wagner coarsening model)and interface-controlled model with a function of r^(2) vs.t(trans-interface diffusion-controlled coarsening model)were investigated to fit between the experimental results and theoretical analysis.It was found that Re as the slowest diffusing solute in the alloy constituted the rate-limited step for coarsening based on LSW model,while the process limiting coarsening as governed by an interface diffusion process could possibly be related to the Al diffusion through theγ/γ'interface.The PSDs and coarsening exponent were discussed by comparing the experimental data with predictions of LSW and TIDC models.Finally,coarsening mechanism could be divided into four regimes:(i)coarsening by diffusion-controlled;(ii)coarsening by diffusion and interface cocontrolled;(iii)coarsening by interface-controlled;(iv)coarsening by interface-controlled accompanied withγ'coalescence.
基金supported by the National Natural Science Foundation of China(Nos.51875211 and 51375171)Beijing Natural Science Foundation(No.L223001)+1 种基金Natural Science Foundation of Guangdong Province(No.2023A1515012730)the Program for New Century Excellent Talents in University in China(No.NCET-08-0209).
文摘Al and Mg alloy high pressure die castings(HPDC)are increasingly used in automotive industries.The microstructures in the castings have decisive effect on the casting mechanical properties,in which the microstructure characteristics are fundamental for the investigation of the microstructure-property relation.During the past decade,the microstructure characteristics of HPDC Al and Mg alloys,especially micro-pores andα-Fe,have been investigated from two-dimensional(2D)to threedimensional with X-ray micro-computed tomography(μ-CT).This paper provides an overview of the current understanding regarding the 3D characteristics and formation mechanisms of microstructures in HPDC alloys,their spatial distributions,and the impact on mechanical properties.Additionally,it outlines future research directions for the formation and control of heterogeneous microstructures in HPDC alloys.
