期刊文献+
任意字段
题名或关键词
题名
关键词
摘要
作者
第一作者
机构
刊名
分类号
参考文献
作者简介
基金资助
栏目信息
共找到854篇文章
< 1 2 … 43 >
每页显示 20 50 100
已选0条
引用分析
参考文献
引证文献
 统计分析
检索结果
已选文献
显示方式：
Phase-based polarized direct envelope inversion with total variation regularization for simultaneous source seismic data:Application to SEG 2014 Chevron blind test dataset 认领 引用
1
作者 Yong Hu Xi-Zhu Guan +2 位作者 Li-Yun Fu Yi-Bo Wang Ru-Shan Wu 《Petroleum Science》 SCIE EI CAS CSCD 2026年第6期3248-3269,共22页
In subsalt hydrocarbon exploration,the strong velocity contrast associated with salt structures poses significant challenges to conventional full waveform inversion(FWI)method.While direct envelope inversion can inver... In subsalt hydrocarbon exploration,the strong velocity contrast associated with salt structures poses significant challenges to conventional full waveform inversion(FWI)method.While direct envelope inversion can invert large-scale salt dome,it fails to invert the salt-bottom velocity structures due to the absence of waveform phase information.To solve this problem,we first use a sliding Gaussian window to decompose seismic data into the local scale waveform.Subsequently,we combine the local scale envelope signal with waveform instantaneous phase to obtain the polarity envelope.The resulting polarity envelope can invert low-frequency components while preserving the phase characteristics of seismic data,enabling more accurate low-wavenumber velocity structures.Based on this,we propose a phase-based polarized direct envelope inversion with total variation regularization for simultaneous source seismic data(simultaneous source TV-PDEI)to improve the accuracy of velocity inversion,remove the crosstalk noise,and enhance the computational efficiency.Numerical experiments on salt models and Chevron blind dataset test demonstrate that the simultaneous source TV-PDEI efficiently provides a robust initial velocity model for FWI. 展开更多
关键词 Full waveform inversion Direct envelope inversion Polarity envelope Chevron blind dataset test Total variation regularization
暂未订购 下载PDF
Numerical simulation of heat transfer through rock envelope of a plant factory in an underground mine tunnel 认领 引用
2
作者 Md Washim Akram Huiqing Guo Wenbin Hu 《Energy and Built Environment》 EI CSCD 2026年第3期672-688,共17页
Conventional plant factories(indoor vertical farming)are energy intensive and affected by surface climate whereas underground mine tunnels have a stable environment,and heat transfer through the surrounding rock envel... Conventional plant factories(indoor vertical farming)are energy intensive and affected by surface climate whereas underground mine tunnels have a stable environment,and heat transfer through the surrounding rock envelope is expected to reduce cooling and heating loads of the environment control systems of the plant factories.The aim of this study is to numerically analyze short and long term heat transfer through the surrounding rock envelope for an underground plant factory(UGPF)located in a mine tunnel using ANSYS Fluent software.The model is compared with analytical results with discrepancies of 2.5 and 2.7%for light and dark periods,respectively,indicating the numerical model is acceptable for further utilization in thermal modeling of the UGPF.For the base case of 284 K virgin rock temperature,2.75 W/m.K rock thermal conductivity,303 and 297 K in-door air temperature in light and dark periods,the time weighted average overall heat transfer coefficient is high initially with 4.04 W/m2·K,but reduces rapidly in the first 6 months to 0.75 W/m2·K,then slows down to 0.48 W/m2·K in 3 years when the system almost reaches the equilibrium status.The heat transfer rate and overall heat transfer coefficient reduction with time follow power relationships.The results indicate that long term heat loss to rock envelope instead of initial values should be used in determining the cooling capacity of the plant factory considering the worst-case scenario.The sensitivity analysis shows that the rock thermal conductivity is more influential on heat transfer rate than indoor air temperature and virgin rock temperature,the latter two have similar levels of influence. 展开更多
关键词 Underground mine tunnel Plant factory CFD simulation Rock envelope Dynamic thermal analysis
Stratospheric airship flight trajectory envelope prediction based on wind field uncertainty model 认领 引用
3
作者 Lele QI Xixiang YANG +2 位作者 Xiaolong DENG Fangchao BAI Zhenyu MA 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2026年第6期389-405,共17页
Stratospheric airships,as typical low-speed near space aircraft,exhibit great potential in the fields of communication relay and high-altitude monitoring.However,due to the considerable uncertainty of the external win... Stratospheric airships,as typical low-speed near space aircraft,exhibit great potential in the fields of communication relay and high-altitude monitoring.However,due to the considerable uncertainty of the external wind field environment,the deviation of stratospheric airship flight trajectory increases.To effectively predict the envelope of stratospheric airship flight trajectory,this paper proposes an innovative trajectory envelope prediction method to offer a new perspective on related research.By establishing wind field uncertainty model including both wind speed uncertainty and wind direction uncertainty,stratospheric airship trajectories are obtained under four extreme wind fields,and the trajectory envelope is generated using the Alpha-Shape method.Furthermore,the adaptive bandwidth kernel density estimation method is introduced to quantify the trajectory distribution probability,providing an intuitive description of the trajectory distribution probability.The simulation results show that the proposed methods can effectively predict the stratospheric airship flight trajectory envelope and describe trajectory distribution characteristics,supporting mission planning,risk assessment,and energy-management strategy selection for stratospheric airship flight tests. 展开更多
关键词 Alpha-Shape Flight trajectory envelope Kernel density estimation Stratospheric airship Trajectory distribution probability Worst-to-worst
暂未订购 下载PDF
Non-destructive Testing of Envelope Material Based on Wave Propagation Characteristics 认领 引用
4
作者 Jing Cao Bo Yuan +5 位作者 Kai Wang Jun Wu Zheng-Yang Li Yanchu Yang Dongjia Yan Peijun Wei 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2026年第1期24-35,共12页
Long-duration vehicles in near space have achieved great success;however,the non-destructive testing(NDT)methods for the envelope materials of such long-duration vehicles remain blank.In this paper,we propose the air-... Long-duration vehicles in near space have achieved great success;however,the non-destructive testing(NDT)methods for the envelope materials of such long-duration vehicles remain blank.In this paper,we propose the air-coupled ultrasonic NDT method theoretically.In the theoretical analysis process,the envelope material is simplified as an orthogonal sandwich structure.To calculate the displacement and stress fields of each medium,the state vectors are established and the transfer matrices of the material from the upper interface to the lower interface are obtained by using boundary conditions.Then,linear equations about the amplitude of reflected and transmitted waves are derived by combining the coupling boundary conditions of air and solid.The effects of incident angles,inflation of the envelope material,and debonding of the interfaces on the transmission coefficients are considered.The results show that the air-coupled ultrasonic NDT of the envelope material can be carried out in the pre-inflated state.Finally,a method for identifying interface debonding is proposed based on judging transmission coefficients within a certain frequency range. 展开更多
关键词 Envelope material Non-destructive testing Transfer matrix method Wave propagation Multilayer structure
暂未订购 下载PDF
Three-dimensional path planning algorithm for UAV based on obstacle envelopes 认领 引用
5
作者 ZHOU Yuzhen LIU Yao +1 位作者 HUANG Jincai SHI Jianmai 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2026年第3期1042-1058,共17页
In this paper,a three-dimension envelope-based path planning algorithm(3DE-PP)is proposed to automatically generate a collision-free trajectory for unmanned aerial vehicle(UAV).Firstly,focusing on the defects of low e... In this paper,a three-dimension envelope-based path planning algorithm(3DE-PP)is proposed to automatically generate a collision-free trajectory for unmanned aerial vehicle(UAV).Firstly,focusing on the defects of low efficiency of obstacle modelling representation and large search space,an elliptical envelope-based obstacle modelling method is proposed to facilitate the generation of obstacle avoidance waypoints and improve the search efficiency.Then,considering safety and aiming at minimum energy consumption,waypoint generation strategies based on tangent guidance and minimum deviation are designed.Meanwhile,aiming at the UAV motion constraint,a three-dimension(3D)path construction method based on improved Dubins is proposed.Finally,combined with the main path generation algorithm based on saving algorithm,a safe and feasible 3D flight path is constructed by considering the power constraint of UAV and the access of charging stations comprehensively.The proposed 3DE-PP is compared with four algorithms(SAS,Dubins-RRT*,APF,3D-TG)by 15 examples generated from five typical environments,and the computational results confirm its advantages.Furthermore,a real-world case is introduced,and the key factors influencing path planning are analyzed. 展开更多
关键词 ellipsoidal envelope unmanned aerial vehicle(UAV) path planning obstacle avoidance
暂未订购 下载PDF
A new multi-DOF envelope forming process for fabricating spiral bevel gears with back taper tooth 认领 引用 被引量：1
6
作者 Xinghui HAN Yanhui WANG +3 位作者 Lin HUA Wuhao ZHUANG Fangyan ZHENG Wei FENG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2025年第1期568-585,共18页
Spiral bevel gears are critical transmission components,and are widely used in the aerospace field.This paper proposes a new multi-DOF envelope forming process for fabricating spiral bevel gears.Firstly,the multi-DOF ... Spiral bevel gears are critical transmission components,and are widely used in the aerospace field.This paper proposes a new multi-DOF envelope forming process for fabricating spiral bevel gears.Firstly,the multi-DOF envelope forming principle of spiral bevel gears is proposed.Secondly,the design methods for the envelope tool geometry and movement are proposed based on the envelope geometry and movement relationships.Thirdly,the metal flow and tooth filling laws are revealed through 3D FE simulation of the multi-DOF envelope forming process of a typical spiral bevel gear.Fourthly,a new method for separating the envelope tool and the formed spiral bevel gear with back taper tooth is proposed to avoid their interference.Finally,experiments on multi-DOF envelope forming of this typical spiral bevel gear are conducted using new heavy load multi-DOF envelope forming equipment.The simulation and experimental results show the feasibility of the proposed multi-DOF envelope forming process for fabricating spiral bevel gears with back taper tooth and the corresponding process design methods. 展开更多
关键词 Multi-DOF envelope forming Spiral bevel gear Back taper tooth Metal flow Process design
暂未订购 下载PDF
A novel sliding mode control method with enhanced permanent magnet synchronous motor parameter identification for heavy load multi-DOF envelope forming press 认领 引用
7
作者 Xinghui HAN Xin CHEN +2 位作者 Fangyan ZHENG Lin HUA Wuhao ZHUANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2025年第11期396-412,共17页
To achieve the manufacturing of Thin-Wall and High-Rib Components(TWHRC)with high precision,a novel heavy load Multi-DOF Envelope Forming Press(MEFP)with Parallel Kinematic Mechanism(PKM),driven by six Permanent Magne... To achieve the manufacturing of Thin-Wall and High-Rib Components(TWHRC)with high precision,a novel heavy load Multi-DOF Envelope Forming Press(MEFP)with Parallel Kinematic Mechanism(PKM),driven by six Permanent Magnet Synchronous Motors(PMSMs),is developed.However,on account of the heavy forming load,the PMSM parameters are in great variation.Meanwhile,the PMSM is always in a transient state caused by fast time-varying forming load,resulting in low identification precision of varied PMSM parameters and control precision of PMSM under traditional parameter identification methods.To solve this problem,a novel Sliding Mode Control Method with Enhanced PMSM Parameter Identification(SMCMEPPI)for heavy load MEFP is proposed.Firstly,the kinematic model of MEFP is established.Secondly,the variation law of PMSM parameters under heavy load is revealed.Thirdly,an enhanced PMSM parameter identification method is proposed,in which the q axis current of PMSM is used to represent the changing rate of forming load and the adjustment factor is first proposed to remove improper input of PMSM parameter identification online.Fourthly,the Electromechanical Coupling Dynamic Model(ECDM)of MEFP,which includes identified PMSM parameters,is developed.Finally,based on the developed ECDM,a novel SMCMEPPI is proposed to realize the high-precision control of heavy load MEFP.The experimental results indicate that the proposed SMCMEPPI can significantly improve the control precision of heavy load MEFP. 展开更多
关键词 Electromechanical coupling dynamic model Enhanced parameter identification Multi-DOF envelope forming press Parallel kinematic mechanism Sliding mode control
暂未订购 下载PDF
Flight envelope constrained UAV shipboard landing control within an identified quiescent period 认领 引用
8
作者 Cheng ZHANG Tao SONG +1 位作者 Hong TAO Tao JIANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2025年第8期498-511,共14页
UAV shipboard landing poses significant challenges in terms of safety and efficiency,due to the oscillatory ship motion caused by wave interactions and wind gusts,especially in rough sea states.To solve this issue,a f... UAV shipboard landing poses significant challenges in terms of safety and efficiency,due to the oscillatory ship motion caused by wave interactions and wind gusts,especially in rough sea states.To solve this issue,a flight envelope constrained fixed-time control strategy is proposed to achieve a reliable UAV landing on a maneuvering ship.Firstly,a sliding data window autoregressive model is designed to predict the ship's roll and pitch motions,which are accordingly utilized to identify an appropriate quiescent period for safe landing.Subsequently,a barrier-function-based nonsingular terminal sliding mode controller is developed to eliminate the tracking errors within the identified quiescent period,while ensuring the errors remain bounded to satisfy flight envelope constraints.In particular,lumped disturbance components are estimated by integrating a fixed-time disturbance observer and compensated in the controller.The key advantage of the proposed approach is that it well balances the control requirements between precise landing position and safe landing attitude,guaranteeing both steady-state performance and transient behavior of the tracking error.Finally,comparative Gazebo simulations in different sea state scenarios are conducted to verify the satisfactory control performance. 展开更多
关键词 Unmanned aerial vehicle Shipboard landing Ship motion prediction Flight envelope Sliding mode control
暂未订购 下载PDF
Forming Laws and Processing Designing Methods for Multi-DOF Envelope Forming Process of Brake Pad Baseboard 认领 引用
9
作者 Xinghui Han Wei Xiong +3 位作者 Wuhao Zhuang Lin Hua Fangyan Zheng Jingyu Liu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2025年第6期501-516,共16页
To improve braking performance and achieve lightweight in transport equipment,it is necessary to implement overall plastic forming manufacturing of the brake pad baseboard(BPB),which is the core safety component of th... To improve braking performance and achieve lightweight in transport equipment,it is necessary to implement overall plastic forming manufacturing of the brake pad baseboard(BPB),which is the core safety component of the brake system.This study presents an innovative multi-DOF envelope forming(MDFEF)process to realize the plastic forming of BPB with thin skin and high reinforcing ribs.The MDFEF principle for BPB,and the design methods for the envelope mold are first presented.Through FE simulations,the behavior of metal flow,uneven growth pattern of reinforcing ribs,evolution of equivalent strain and evolution of forming force in MDFEF of BPB are investigated.To realize MDFEF,an innovative MDFEF equipment driven by parallel linkages is exploited.The force states of linkages in MDFEF are calculated,and the reasonable mold position is determined to reduce the maximum force on the linkages and improve the service performance of MDFEF equipment.The MDFEF experiments of BPB are conducted and qualified BPB is obtained,which demonstrates that the presented MDFEF process and equipment are applicable to manufacture BPB with thin skin and high reinforcing ribs. 展开更多
关键词 Multi-DOF envelope forming Component with thin skin and reinforcing ribs Brake pad baseboard Forming laws Processing designing
暂未订购 下载PDF
Calibration of Four Nonlinear Failure Envelopes from Triaxial Test Data and Influence of Nonlinearity on Geotechnical Computations 认领 引用 被引量：1
10
作者 Amaechi J. Anyaegbunam Fidelis O. Okafor 《Geomaterials》 2021年第2期42-57,共16页
It is now recognized that many geomaterials have nonlinear failure envelopes. This non-linearity is most marked at lower stress levels, the failure envelope being of quasi-parabolic shape. It is not easy to calibrate ... It is now recognized that many geomaterials have nonlinear failure envelopes. This non-linearity is most marked at lower stress levels, the failure envelope being of quasi-parabolic shape. It is not easy to calibrate these nonlinear failure envelopes from triaxial test data. Currently only the power-type failure envelope has been studied with an established formal procedure for its determination from triaxial test data. In this paper, a simplified procedure is evolved for the development of four different types of nonlinear envelopes. These are of invaluable assistance in the evaluation of true factors of safety in problems of slope stability and correct computation of lateral earth pressure and bearing capacity. The use of the Mohr-Coulomb failure envelopes leads to an overestimation of the factors of safety and other geotechnical quantities. 展开更多
关键词 Calibration of Nonlinear Failure Envelope Triaxial Test Data Modified Maksimovic Envelope Power-Type Envelope Polynomial-Type Envelope Hoek-Brown Envelope Standard Error of Estimate
暂未订购 下载PDF
JCMT observations of CO, SO2, and a U-line in circumstellar envelopes of four O-rich AGB stars 认领 引用
11
作者 Yanan Feng Xiaohu Li +4 位作者 Sheng-Li Qin Tom J.Millar Ryszard Szczerba Zhenzhen Miao Juan Tuo 《Chinese Physics B》 SCIE EI CAS CSCD 2025年第6期693-699,共7页
The circumstellar envelopes(CSE) of asymptotic giant branch(AGB) stars are abundant in molecular emissions, offering valuable insights into the physical and chemical conditions of these evolving stars. In this paper, ... The circumstellar envelopes(CSE) of asymptotic giant branch(AGB) stars are abundant in molecular emissions, offering valuable insights into the physical and chemical conditions of these evolving stars. In this paper, we report observations of two molecules(CO and SO2) toward four O-rich AGB stars using the James Clerk Maxwell Telescope(JCMT). We detected an unusual SO2 spectral feature comprising both broad and narrow components in IK Tau and AP Lyn. The broad line profiles may originate from thermal molecular emission, while the narrow profiles could come from other species(or masers) or astrophysical phenomena occurring within the CSEs of the AGB stars, such as episodic mass loss, bipolar outflows, or emissions associated with the complex physical processes near the central star. The narrow lines of SO2 may also arise from vibrationally excited emissions. Additionally, we observed the same U-line in both TX Cam and IK Tau, which may originate from the molecule N17O. We analyzed the identified molecular lines using rotational diagrams to determine their excitation temperatures, column densities, and fractional abundances. This information aids in the constructing of reliable astrochemical models for a more detailed examination of the target stars. The narrow component of the SO2 line suggests unusual astrophysical phenomena, making IK Tau and AP Lyn particularly intriguing for further investigation to fully understand the physical processes at play in these sources. 展开更多
关键词 asymptotic giant branch circumstellar envelopes SO2
暂未订购 下载PDF
Adjusting Accuracy of Digital Image Correlation Through Variable Subsets and Application in Airship Envelope 认领 引用
12
作者 ZHU Fangtao VWANG Quanbao +1 位作者 XIE Weicheng DUAN Dengping 《Journal of Shanghai Jiaotong university(Science)》 EI 2025年第2期239-251,共13页
The stratospheric airship is affected by harsh conditions in the stratosphere environment.To ensure the safety of the airship,it is necessary to detect the material state of the airship envelope.Since digital image co... The stratospheric airship is affected by harsh conditions in the stratosphere environment.To ensure the safety of the airship,it is necessary to detect the material state of the airship envelope.Since digital image correlation possesses non-contact strain measurement ability,this paper explores the infuence of different shapes of the subset on measurement accuracy.Through the results,it is found that increasing the aspect ratio of subsets can improve the strain accuracy measured in the c-direction,and reducing the aspect ratio can improve the strain accuracy measured in the y-direction.This trend becomes more obvious as the strain increases.Based on this discovery,a subset adaptive algorithm is proposed.The feasibility of the algorithm is verified by experiments,and the precision of strain measurement can be effectively improved by adjusting the threshold value.Therefore,the algorithm can be utilized to increase the measurement accuracy in the larger strain direction without changing the size of the subset. 展开更多
关键词 shape of subset digital image correlation strain of airship envelope self-adaptive selection
暂未订购 下载PDF
Strain transfer of surface-bonded fiber Bragg grating sensors for airship envelope structural health monitoring 认领 引用 被引量：21
13
作者 Hai-tao ZHAO Quan-bao WANG +3 位作者 Ye QIU Ji-an CHEN Yue-ying WANG Zhen-min FAN 《Journal of Zhejiang University-SCIENCE A》 SCIE EI CAS CSCD 2012年第7期538-545,共8页
This paper deals with an improved bonding approach of surface-bonded fiber Bragg grating (FBG) sensors for airship envelope structural health monitoring (SHM) under the strain transfer theory. A theoretical formula is... This paper deals with an improved bonding approach of surface-bonded fiber Bragg grating (FBG) sensors for airship envelope structural health monitoring (SHM) under the strain transfer theory. A theoretical formula is derived from the proposed model to predict the strain transfer relationship between the airship envelope and fiber core. Then theoretical predictions are validated by numerical analysis using the finite element method (FEM). Finally, on the basis of the theoretical approach and numerical validation, parameters that influence the strain transfer rate from the airship envelope to fiber core and the ratio of effective sensing length are analyzed, and some meaningful conclusions are provided. 展开更多
关键词 Airship envelope Fiber Bragg grating （FBG） Surface-bonded Strain transfer Structural health monitoring （SHM）
暂未订购 下载PDF
Implementation of Envelope Analysis on a Wireless Condition Monitoring System for Bearing Fault Diagnosis 认领 引用 被引量：31
14
作者 Guo-Jin Feng James Gu +3 位作者 Dong Zhen Mustafa Aliwan Feng-Shou Gu Andrew D.Ball 《International Journal of Automation and computing》 CSCD 2015年第1期14-24,共11页
Envelope analysis is an effective method for characterizing impulsive vibrations in wired condition monitoring(CM)systems. This paper depicts the implementation of envelope analysis on a wireless sensor node for obtai... Envelope analysis is an effective method for characterizing impulsive vibrations in wired condition monitoring(CM)systems. This paper depicts the implementation of envelope analysis on a wireless sensor node for obtaining a more convenient and reliable CM system. To maintain CM performances under the constraints of resources available in the cost effective Zigbee based wireless sensor network(WSN), a low cost cortex-M4 F microcontroller is employed as the core processor to implement the envelope analysis algorithm on the sensor node. The on-chip 12 bit analog-to-digital converter(ADC) working at 10 k Hz sampling rate is adopted to acquire vibration signals measured by a wide frequency band piezoelectric accelerometer. The data processing flow inside the processor is optimized to satisfy the large memory usage in implementing fast Fourier transform(FFT) and Hilbert transform(HT). Thus, the envelope spectrum can be computed from a data frame of 2048 points to achieve a frequency resolution acceptable for identifying the characteristic frequencies of different bearing faults. Experimental evaluation results show that the embedded envelope analysis algorithm can successfully diagnose the simulated bearing faults and the data transmission throughput can be reduced by at least 95% per frame compared with that of the raw data, allowing a large number of sensor nodes to be deployed in the network for real time monitoring. 展开更多
关键词 Wireless sensor network(WSN) envelope analysis fault diagnosis local processing Hilbert transformation
暂未订购 下载PDF
Pepper mild mottle virus coat protein interacts with pepper chloroplast outer envelope membrane protein OMP24 to inhibit antiviral immunity in plants 认领 引用 被引量：9
15
作者 Kelei Han Hongying Zheng +11 位作者 Dankan Yan Huijie Zhou Zhaoxing Jia Yushan Zhai Jian Wu Yuwen Lu Guanwei Wu Shaofei Rao Jianping Chen Jiejun Peng Rende Qi Fei Yan 《Horticulture Research》 SCIE CSCD 2023年第5期16-28,共13页
Pepper mild mottle virus(PMMoV)is a devastating viral pathogen of pepper(Capsicum annuum)but it is unclear whether and how peppers protect against PMMoV infection.The expression of the chloroplast outer membrane prote... Pepper mild mottle virus(PMMoV)is a devastating viral pathogen of pepper(Capsicum annuum)but it is unclear whether and how peppers protect against PMMoV infection.The expression of the chloroplast outer membrane protein 24(OMP24)of C.annuum was upregulated under PMMoV infection and it interacted with PMMoV coat protein(CP).Silencing of OMP24 in either C.annuum or Nicotiana benthamiana facilitated PMMoV infection,whereas overexpression of N.benthamiana OMP24 in transgenic plants inhibited PMMoV infection.Both C.annuum OMP24(CaOMP24)and N.benthamiana OMP24(NbOMP24)localized to the chloroplast and have a moderately hydrophobic transmembrane domain that is necessary for their localization.Overexpression of CaOMP24 induced stromules,perinuclear chloroplast clustering,and accumulation of reactive oxygen species(ROS),the typical defense responses of chloroplasts transferring the retrograde signaling to the nucleus to regulate resistance genes.The expression of PR1 and PR2 was also upregulated significantly in plants overexpressing OMP24.Self-interaction of OMP24 was demonstrated and was required for OMP24-mediated plant defense.Interaction with PMMoV CP interfered with the self-interaction of OMP24 and impaired OMP24-induced stromules,perinuclear chloroplast clustering and ROS accumulation.The results demonstrate the defense function of OMP24 in pepper during viral infection and suggest a possible mechanism by which PMMoV CP modulates the plant defense to facilitate viral infection. 展开更多
关键词 outer immunity envelope
暂未订购 下载PDF
An active pipe-embedded building envelope for utilizing low-grade energy sources 认领 引用 被引量：10
16
作者 谢军龙 朱求源 徐新华 《Journal of Central South University》 SCIE EI CAS 2012年第6期1663-1667,共5页
An active pipe-embedded building envelope, which is an external wall or roof with pipes embedded inside, was presented. This structure may utilize the circulating water in the pipe to transfer heat or coolth inside di... An active pipe-embedded building envelope, which is an external wall or roof with pipes embedded inside, was presented. This structure may utilize the circulating water in the pipe to transfer heat or coolth inside directly. This kind of structure is named ＂active pipe-embedded building envelope＂ due to dealing with the thermal energy actively inside the structure mass by circulating water. This structure not only deals with thermal energy before the external disturbance becomes cooling/heating load by using the circulating water, but also may use low-grade energy sources such as evaporative cooling, solar energy, and geothermal energy. In the meantime, this structure can also improve the indoor thermal comfort by tempering the internal wall surface temperature variation due to the thermal removal in the mass. This work further presents the thermal performance of this structure under a typical hot summer weather condition by comparing it with that of the conventional external walloof with numerical simulation. The results show that this pipe-embedded structure may reduce the external heat transfer significantly and reduce the internal wall surface temperature for improving thermal comfort. This work also presents the effects of the water temperature and the pipe spacing on the heat transfer of this structure. The internal surface heat transfer may reduce by about 2.6 W/mE when the water temperature reduces by 1℃ as far as a brick wall with pipes embedded inside is concerned. When the pipe spacing reduces by 50 mm, the internal wall surface heat flux can also reduce by about 2.3 W/m2. 展开更多
关键词 active pipe-embedded building envelope thermal performance thermal comfort simulation analysis low-grade energy source pipe spacing
暂未订购 下载PDF
Carrier envelope phase effect on the spatial distribution of high-order harmonic generation in asymmetric molecule 认领 引用 被引量：5
17
作者 Jun Zhang Hai-Feng Liu +3 位作者 Xue-Fei Pan Hui Du Jing Guo Xue-Shen Liu 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第5期135-139,共5页
The spatial distribution in high-order harmonic generation(HHG)from the asymmetric diatomic molecule He H2+is investigated by numerically solving the non-Born–Oppenheimer time-dependent Schr?dinger equation(TDSE).... The spatial distribution in high-order harmonic generation(HHG)from the asymmetric diatomic molecule He H2+is investigated by numerically solving the non-Born–Oppenheimer time-dependent Schr?dinger equation(TDSE).The spatial distribution of the HHG spectra shows that there is little contribution in HHG around the geometric center of two nuclei(z=1.17 a.u.)and the equilibrium internuclear position of the H nucleus(z=3.11 a.u.).We demonstrate the carrier envelope phase(CEP)effect on the spatial distribution of HHG in a few-cycle laser pulse.The HHG process is investigated by the time evolution of the electronic density distribution.The time–frequency analysis of HHG from two nuclei in HeH2+is presented to further explain the underlying physical mechanism. 展开更多
关键词 high-order harmonic generation spatial distribution asymmetric molecule carrier envelope phase
暂未订购 下载PDF
Convolution-based multi-scale envelope inversion 认领 引用 被引量：10
18
作者 Ding-Jin Liu Jian-Ping Huang Zi-Ying Wang 《Petroleum Science》 SCIE CAS CSCD 2020年第2期352-362,共11页
Envelope inversion(El)is an efficient tool to mitigate the nonlinearity of conventional full waveform inversion(FWI)by utilizing the ultralow-frequency component in the seismic data.However,the performance of envelope... Envelope inversion(El)is an efficient tool to mitigate the nonlinearity of conventional full waveform inversion(FWI)by utilizing the ultralow-frequency component in the seismic data.However,the performance of envelope inversion depends on the frequency component and initial model to some extent.To improve the convergence ability and avoid the local minima issue,we propose a convolution-based envelope inversion method to update the low-wavenumber component of the velocity model.Besides,the multi-scale inversion strategy(MCEI)is also incorporated to improve the inversion accuracy while guaranteeing the global convergence.The success of this method relies on modifying the original envelope data to expand the overlap region between observed and modeled envelope data,which in turn expands the global minimum basin of misfit function.The accurate low-wavenumber component of the velocity model provided by MCEI can be used as the migration model or an initial model for conventional FWI.The numerical tests on simple layer model and complex BP 2004 model verify that the proposed method is more robust than El even when the initial model is coarse and the frequency component of data is high. 展开更多
关键词 Full waveform inversion Multi-scale strategy Envelope inversion
暂未订购 下载PDF
Rolling Bearing Feature Frequency Extraction using Extreme Average Envelope Decomposition 认领 引用 被引量：6
19
作者 SHI Kunju LIU Shulin +1 位作者 JIANG Chao ZHANG Hongli 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第5期1029-1036,共8页
The vibration signal contains a wealth of sensitive information which reflects the running status of the equipment.It is one of the most important steps for precise diagnosis to decompose the signal and extracts the e... The vibration signal contains a wealth of sensitive information which reflects the running status of the equipment.It is one of the most important steps for precise diagnosis to decompose the signal and extracts the effective information properly.The traditional classical adaptive signal decomposition method,such as EMD,exists the problems of mode mixing,low decomposition accuracy etc.Aiming at those problems,EAED(extreme average envelope decomposition)method is presented based on EMD.EAED method has three advantages.Firstly,it is completed through midpoint envelopment method rather than using maximum and minimum envelopment respectively as used in EMD.Therefore,the average variability of the signal can be described accurately.Secondly,in order to reduce the envelope errors during the signal decomposition,replacing two envelopes with one envelope strategy is presented.Thirdly,the similar triangle principle is utilized to calculate the time of extreme average points accurately.Thus,the influence of sampling frequency on the calculation results can be significantly reduced.Experimental results show that EAED could separate out single frequency components from a complex signal gradually.EAED could not only isolate three kinds of typical bearing fault characteristic of vibration frequency components but also has fewer decomposition layers.EAED replaces quadratic enveloping to an envelope which ensuring to isolate the fault characteristic frequency under the condition of less decomposition layers.Therefore,the precision of signal decomposition is improved. 展开更多
关键词 adaptive signal decomposition extreme average envelope decomposition EMD fault diagnosis
暂未订购 下载PDF
Radial envelope forming mechanism and process design method for cylindrical rings with thin wall and high web ribs 认领 引用 被引量：4
20
作者 Xinghui HAN Yanlei MIN +4 位作者 Wuhao ZHUANG Lin HUA Duanyang TIAN Zushen DENG Ningbo LIU 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2023年第12期461-476,共16页
Cylindrical rings with thin wall and high web ribs(CRTWHWR)are widely used as the key load bearing structures such as rocket body and space station cabin in aerospace field.However,it is still difficult to efficiently... Cylindrical rings with thin wall and high web ribs(CRTWHWR)are widely used as the key load bearing structures such as rocket body and space station cabin in aerospace field.However,it is still difficult to efficiently manufacture CRTWHWR with high performance because of their extreme geometry with thin-walled skins,high web ribs and large size.In this paper,a novel radial envelope forming process is put forward to efficiently achieve the plastic forming of CRTWHWR with high performance.Firstly,the principle of radial envelope forming process is clarified.Then,an efficient design method for the tool motion and geometry is proposed based on the reverse envelope principle,i.e.,CRTWHWR is adopted to reversely envelope the tool and thus the tool which does not interfere with CRTWHWR can be efficiently obtained in a single operation.Finally,a reasonable 3D FE model of the radial envelope forming process of CRTWHWR is established and the radial envelope forming mechanism of CRTWHWR is comprehensively revealed.Through the FE simulation and experiments with material of plastic mud,a typical CRTWHWR with diameter of 300 mm,axial height of 192 mm,the maximum rib height of 25 mm,the minimum rib thickness of 3 mm and skin thickness of 5 mm is radial envelope formed,i.e.,the ratio of the maximum rib height to the minimum rib thickness reaches 8.33,the ratio of the maximum rib height to skin thickness reaches 5 and the ratio of diameter to the minimum rib thickness reaches 100.The above results verify that the proposed radial envelope forming process has great potentials in efficiently manufacturing CRTWHWR with extreme geometry. 展开更多
关键词 Radial envelope forming Cylindrical ring with thin wall and high web ribs Forming mechanism FE simulation Tool design
暂未订购 下载PDF
已选0条
引用分析
参考文献
引证文献
 统计分析
检索结果
已选文献
上一页 1 2 … 43 下一页 到第 页
在线咨询 使用帮助 返回顶部 意见反馈