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Vibration Transfer Function of Railway Vehicle System and its Spatial Coherence Under Vertical Track Irregularity Conditions
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作者 Peng Lu Xi Wang Yu Hou 《Chinese Journal of Mechanical Engineering》 2025年第2期374-393,共20页
Current research on rail vehicle system vibrations primarily relies on numerical methods,with vibration transfer functions commonly derived through data fitting.However,the physical mechanisms underlying these vibrati... Current research on rail vehicle system vibrations primarily relies on numerical methods,with vibration transfer functions commonly derived through data fitting.However,the physical mechanisms underlying these vibrations are not well understood.To clarify the vibration transfer function and its characteristics,four basic input vectors are defined,and an analytical method is proposed.The vibration transfer functions of the vehicle system are solved,and their spatial coherence is analyzed.The results show that there are two spatial scales and four coherent modes in the vehicle system.The track irregularity wavelengths are combined with two spatial scales to alter the proportions of basic input vectors and then show the characteristics of spatial coherence.Four coherent modes are involved in wheel-rail force and primary suspension force;two coherent modes are involved in bogie vertical motion;and their dominant modes vary with the input frequency.On the other hand,the coherent modes involved in the bogie pitching motion and vehicle body motion are single and fixed over the whole range of frequency.This study presents an analytical method for the rapid solution of dynamic responses in vehicle systems and systematically analyzes the coherence behavior of vibration transfer functions with respect to tracking irregularity wavelengths. 展开更多
关键词 Vertical track irregularity Vibration transfer function Spatial coherence Dominant mode transfer matrix method
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Transfer function modeling and analysis of the open-loop Buck converter using the fractional calculus 被引量:11
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作者 王发强 马西奎 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第3期232-239,共8页
Based on the fact that the real inductor and the real capacitor are fractional order in nature and the fractional calculus,the transfer function modeling and analysis of the open-loop Buck converter in a continuous co... Based on the fact that the real inductor and the real capacitor are fractional order in nature and the fractional calculus,the transfer function modeling and analysis of the open-loop Buck converter in a continuous conduction mode(CCM) operation are carried out in this paper.The fractional order small signal model and the corresponding equivalent circuit of the open-loop Buck converter in a CCM operation are presented.The transfer functions from the input voltage to the output voltage,from the input voltage to the inductor current,from the duty cycle to the output voltage,from the duty cycle to the inductor current,and the output impedance of the open-loop Buck converter in CCM operation are derived,and their bode diagrams and step responses are calculated,respectively.It is found that all the derived fractional order transfer functions of the system are influenced by the fractional orders of the inductor and the capacitor.Finally,the realization of the fractional order inductor and the fractional order capacitor is designed,and the corresponding PSIM circuit simulation results of the open-loop Buck converter in CCM operation are given to confirm the correctness of the derivations and the theoretical analysis. 展开更多
关键词 Buck converter small signal equivalent circuit model fractional calculus transfer function
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Design method of multivariable PI controller for turboprop engine based on equivalent transfer function
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作者 Shancheng LI Yong WANG Haibo ZHANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2024年第9期237-260,共24页
Traditional centralized Proportional Integral(PI)controller design methods based on Equivalent Transfer Functions(ETFs)have poor decoupling effect in turboprop engines.In this paper,a centralized PI design method base... Traditional centralized Proportional Integral(PI)controller design methods based on Equivalent Transfer Functions(ETFs)have poor decoupling effect in turboprop engines.In this paper,a centralized PI design method based on dynamic imaginary matrix and equivalent transfer function is proposed.Firstly,a method for solving equivalent transfer functions based on the dynamic imaginary matrix is proposed,which adopts dynamic imaginary matrix to describe the dynamic characteristics of the system,and obtains the equivalent transfer function based on the dynamic imaginary matrix characteristics.Secondly,for the equivalent transfer function,a central-ized PI control gain is designed using the Taylor expansion method.Meanwhile,this paper further proves that the centralized PI design method proposed in this paper has integral stability.Consid-ering the impact of altitude and Mach number on turboprop engines,a linear feedforward control method based on the transfer function matrix is further proposed based on the centralized PI con-troller,and the stability of the entire comprehensive control method is proved.Finally,to ensure the safe and effective operation of the turboprop engine,a temperature and torque limiting protection controller is designed for the turboprop engine.Simulation results show that the centralized PI con-troller design method and linear feedforward control method proposed can effectively improve the control quality of turboprop engine control systems. 展开更多
关键词 Multivariable control sys-tems Equivalent transfer function Disturbance compensation control Control parameter design Turboprop engine control
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Transfer matrix method for free and forced vibrations of multi-level functionally graded material stepped beams with different boundary conditions
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作者 Xiaoyang SU Tong HU +3 位作者 Wei ZHANG Houjun KANG Yunyue CONG Quan YUAN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第6期983-1000,共18页
Functionally graded materials(FGMs)are a novel class of composite materials that have attracted significant attention in the field of engineering due to their unique mechanical properties.This study aims to explore th... Functionally graded materials(FGMs)are a novel class of composite materials that have attracted significant attention in the field of engineering due to their unique mechanical properties.This study aims to explore the dynamic behaviors of an FGM stepped beam with different boundary conditions based on an efficient solving method.Under the assumptions of the Euler-Bernoulli beam theory,the governing differential equations of an individual FGM beam are derived with Hamilton’s principle and decoupled via the separation-of-variable approach.Then,the free and forced vibrations of the FGM stepped beam are solved with the transfer matrix method(TMM).Two models,i.e.,a three-level FGM stepped beam and a five-level FGM stepped beam,are considered,and their natural frequencies and mode shapes are presented.To demonstrate the validity of the method in this paper,the simulation results by ABAQUS are also given.On this basis,the detailed parametric analyses on the frequencies and dynamic responses of the three-level FGM stepped beam are carried out.The results show the accuracy and efficiency of the TMM. 展开更多
关键词 transfer matrix method(TMM) free vibration forced vibration functionally graded material(FGM) stepped beam
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Resting-state brain network remodeling after different nerve reconstruction surgeries:a functional magnetic resonance imaging study in brachial plexus injury rats
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作者 Yunting Xiang Xiangxin Xing +6 位作者 Xuyun Hua Yuwen Zhang Xin Xue Jiajia Wu Mouxiong Zheng He Wang Jianguang Xu 《Neural Regeneration Research》 SCIE CAS 2025年第5期1495-1504,共10页
Distinct brain remodeling has been found after different nerve reconstruction strategies,including motor representation of the affected limb.However,differences among reconstruction strategies at the brain network lev... Distinct brain remodeling has been found after different nerve reconstruction strategies,including motor representation of the affected limb.However,differences among reconstruction strategies at the brain network level have not been elucidated.This study aimed to explore intranetwork changes related to altered peripheral neural pathways after different nerve reconstruction surgeries,including nerve repair,endto-end nerve transfer,and end-to-side nerve transfer.Sprague–Dawley rats underwent complete left brachial plexus transection and were divided into four equal groups of eight:no nerve repair,grafted nerve repair,phrenic nerve end-to-end transfer,and end-to-side transfer with a graft sutured to the anterior upper trunk.Resting-state brain functional magnetic resonance imaging was obtained 7 months after surgery.The independent component analysis algorithm was utilized to identify group-level network components of interest and extract resting-state functional connectivity values of each voxel within the component.Alterations in intra-network resting-state functional connectivity were compared among the groups.Target muscle reinnervation was assessed by behavioral observation(elbow flexion)and electromyography.The results showed that alterations in the sensorimotor and interoception networks were mostly related to changes in the peripheral neural pathway.Nerve repair was related to enhanced connectivity within the sensorimotor network,while end-to-side nerve transfer might be more beneficial for restoring control over the affected limb by the original motor representation.The thalamic-cortical pathway was enhanced within the interoception network after nerve repair and end-to-end nerve transfer.Brain areas related to cognition and emotion were enhanced after end-to-side nerve transfer.Our study revealed important brain networks related to different nerve reconstructions.These networks may be potential targets for enhancing motor recovery. 展开更多
关键词 brain functional networks end-to-end nerve transfer end-to-side nerve transfer independent component analysis nerve repair peripheral plexus injury resting-state functional connectivity
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MXene-induced electronic structure modulation of Fe-Al-LDH to boost the Fenton-like Reaction:Singlet oxygen evolution and electron-transfer mechanisms 被引量:1
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作者 Zhongzhu Yang Zeyan Zhou +2 位作者 Xiaofei Tan Guangming Zeng Chang Zhang 《Journal of Materials Science & Technology》 2025年第1期224-237,共14页
Layered double hydroxide(LDH)based heterogonous peroxymonosulfate(PMS)activation degradation of pollutants has attracted extensive attention.The challenge is to selectively regulate the traditional free radical domina... Layered double hydroxide(LDH)based heterogonous peroxymonosulfate(PMS)activation degradation of pollutants has attracted extensive attention.The challenge is to selectively regulate the traditional free radical dominant degradation pathway into a nonradical degradation pathway.Herein,an interface ar-chitecture of Ti_(3) C_(2) T_(x)-MXene(MXene)loading on the Fe-Al LDH scaffold was developed,which showed excellent stability and robust resistance against harsh conditions.Significantly,the rate constant for tetra-cycline hydrochloride(TC)degradation in the MXene-LDH/PMS process was 0.421 min^(-1),which was ten times faster than the rate constant for pure Fe-Al LDH(0.042 min^(-1)).Specifically,more reactive Fe with the closer d-band center to the Fermi level results in higher electron transfer efficiency.The occupa-tions of Fe-3d orbitals in Mxene/Fe-Al LDH are pushed above the Fermi level to generate,which results in higher PMS adsorption and inhibition of the release of oxygen-containing active species intermedi-ates,leading to the enhanced^(1)O_(2) generation.Additionally,the built-in electric field in the heterojunc-tion was driven by the charge redistribution between MXene and Fe-Al LDH,resulting in a mediated-electron transfer mechanism,differentiating it from the Fe-Al LDH/PMS system.It was fascinating that MXene/Fe-Al LDH achieved satisfactory treatment efficiency in continuous column reactor and real landfill leachate. 展开更多
关键词 Interface engineering Density functional theory Layered double hydroxides PEROXYMONOSULFATE Electron transfer
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Factors of intention to learning transfer in apprenticeships:Results and implications of a chain mediation model
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作者 Xin-Xin Chen Young-Sup Hyun Wen-Hao Chen 《Journal of Psychology in Africa》 2025年第3期393-401,共9页
This study utilized a sequential mediating model to examine the role of motivation to learn and transfer selfefficacy in the relationships between perceived content validity,mentoring function,continuous learning work... This study utilized a sequential mediating model to examine the role of motivation to learn and transfer selfefficacy in the relationships between perceived content validity,mentoring function,continuous learning work culture and intention to transfer learning.The sample comprized 429 final-year apprentices in Guangdong province,China(females=69.9%,Engineering&Medicine=69%,mean age=20.99,SD=1.60).The apprentices completed standardized measures of motivation to learn,transfer self-efficacy perceived content validity,mentoring function,and continuous learning work culture.Structural equation modeling was used to analyze the data.Results showed perceived content validity,mentoring function,continuous learning culture to predict intention to transfer learning.Of these factors,perceived content validity was the strongest predictor of intention to transfer learning.Of these factors,perceived content validity was the most influential predictor of intention to transfer learning.The motivation to learn and transfer self-efficacy sequentially mediated the relationship between mentoring function and intention to learning transfer to be stronger than by either alone.Although perceived content validity and continuous learning culture exhibited no significant direct effects on intention to transfer learning,they demonstrated positive indirect associations with intention to transfer via motivation to learn and transfer self-efficacy.These study findings extend the applications of the learning transfer framework to individuals undergoing apprenticeship training which also would apply to other a long-term work-based learning programs. 展开更多
关键词 intention to learning transfer APPRENTICESHIP transfer self-efficacy motivation to learn mentoring function
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Pd/Cu-cocatalyzed multi-site functionalization of in-situ generated alkenes toward carbazole-based aggregation-induced emission luminogens
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作者 Meiqi Zhang Xueyuan Yan +8 位作者 Zheng Liu Hongyuan Bai Hongwei Ma Genping Huang Bo Zhang Dezhu Xu Wenjia Han Li Han Tenglong Guo 《Chinese Journal of Catalysis》 2025年第2期176-184,共9页
In contrast to the predominant mono or difunctionalization of alkenes,the multi-site functionalization of alkenes involving the synergistic formation of more than two new C–C or C–X bonds is much challenging,especia... In contrast to the predominant mono or difunctionalization of alkenes,the multi-site functionalization of alkenes involving the synergistic formation of more than two new C–C or C–X bonds is much challenging,especially for developing new reaction pathway to afford the functional heterocycle compounds with aggregation-induced emission(AIE)property has been rarely reported.In present work,the multi-site functionalization of in situ generated alkenes with indoles has been developed for the synthesis of diversely functionalized carbazoles through the synergistic construction of multiple C–C bonds and C=O bond.A proposed reaction sequence involving C–H alkenylation/radical oxygen atom transfer/Diels-Alder cycloaddition/dehydrogenative aromatization was supported by experiments and density functional theory calculations.Further derivative carbazole-linked-quinoxaline skeletons represent a class of AIEgens with acceptor-donor-acceptor configuration,which generated the desired twisted intramolecular charge transfer(TICT)AIE properties and could be used as fluorescent probes for detecting the micrometer-sized phase separation of polymer blends.The protocol provides a concise route for the synthesis and application of carbazole-based AIE luminogens. 展开更多
关键词 Multi-site functionalization CARBAZOLES Aggregation-induced emission luminogens Radical oxygen atom transfer Microphase separation
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Janus-type BN-embedded perylene diimides via a“shuffling”strategy:Regioselective functionalizable building block towards high-performance n-type organic semiconductors
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作者 Kexiang Zhao Zongrui Wang +4 位作者 Qi-Yuan Wan Jing-Cai Zeng Li Ding Jie-Yu Wang Jian Pei 《Chinese Chemical Letters》 2025年第6期417-422,共6页
Regioselevtive functionalization of perylene diimides(PDIs)at bay area often requires multistep synthesis and strenuous recrystallization.Direct bromination of perylene diimides only afford the 1,6 and 1,7-regioisomer... Regioselevtive functionalization of perylene diimides(PDIs)at bay area often requires multistep synthesis and strenuous recrystallization.Direct bromination of perylene diimides only afford the 1,6 and 1,7-regioisomers.More importantly,the 1,6-dibromo regioisomers could only be separated by preparative HPLC.Herein,we report a promising strategy for constructing Janus backbone of BN-doped perylene diimide derivatives.This Janus-type configuration results in the unique regioselective functionalization of BN-JPDIs,which yields exclusively the 1,6-regioisomers.Further investigation shows that the Janus-type configuration leads to a net dipole moment of 1.94 D and intramolecular charge transfer,which causes substantial changes on the optoelectronic properties.Moreover,the single crystal organic field-effect transistors based on BN-JPDIs exhibit electron mobilities up to 0.57 cm^(2)V^(-1)s^(-1),showcasing their potential as versatile building block towards high-performance n-type organic semiconductors. 展开更多
关键词 BN heterocycles Perylene diimides Regioselective functionalization Intramolecular charge transfer N-type organic semiconductors
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Critical Bimetallic Phosphide Layer Enables Fast Electron Transfer and Extra Energy Supply for Flexible Quasi‑Solid‑State Zinc Batteries
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作者 Leixin Wu Linfeng Lv +15 位作者 Yibo Xiong Wenwu Wang Xiaoqiao Liao Xiyao Huang Ruiqi Song Zhe Zhu Yixue Duan Lei Wang Zeyu Ma Jiangwang Wang Fazal ul Nisa Kai Yang Muhammad Tahir Longbing Qu Wenlong Cai Liang He 《Nano-Micro Letters》 2025年第11期136-154,共19页
Nickel-based cathodes in aqueous nickel-zinc batteries typically suffer from sluggish reaction kinetics and limited energy density.In situ introduction of metal phosphides and rational construction of heterostructures... Nickel-based cathodes in aqueous nickel-zinc batteries typically suffer from sluggish reaction kinetics and limited energy density.In situ introduction of metal phosphides and rational construction of heterostructures can effectively promote electron/ion transport.However,the complex evolution of phosphidation and intractable phosphidizing degree greatly affect the composition of active phase,active sites,charge transfer rate,and ion adsorption strength of cathodes.Herein,the critical bimetallic phosphide layer(CBPL)is constructed on the NiCo-layered double hydroxide(NiCo-LDH)skeleton by a controllable anion-exchange strategy,yielding a novel nanohybrid cathode(NiCo-P1.0,1.0 representing the mass ratio of Na_(2)H_(2)PO_(2)to NiCo-LDH).The high-conductivity CBPL with the inner NiCo-LDH forms extensive heterostructures,effectively regulating the electronic structure via charge transfer,thereby improving electrical conductivity.Remarkably,the CBPL exhibits unexpected electrochemical activity and synergizes with NiCo-LDH for electrode reactions,ultimately delivering extra energy.Benefiting from the bifunctional CBPL,NiCo-P1.0 delivers an optimal capacity of 286.64 mAh g^(−1)at 1C(1C=289 mAh g^(−1))and superb rate performance(a capacity retention of 72.22%at 40C).The assembled NiCo-P1.0//Zn battery achieves ultrahigh energy/power density(503.62 Wh kg^(−1)/18.62 kW kg^(−1),based on the mass loading of active material on the cathode),and the flexible quasi-solid-state pouch cell validates its practicality.This work demonstrates the superiority of bifunctional CBPL for surface modification,providing an effective and scalable compositing strategy in achieving high-performance cathodes for aqueous batteries. 展开更多
关键词 Bimetallic phosphide layer Dual functionality Fast electron transfer Energy supply Flexible quasi-solid-state batteries
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Seeing the macro in the micro:a diffusion model-based approach for style transfer in cellular images
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作者 Jiayi CAI Yong HE +2 位作者 Feng LIU Byung-Ho KANG Xuping FENG 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 2025年第6期609-612,共4页
The internal structures of cells as the basic units of life are a major wonder of the microscopic world.Cellular images provide an intriguing window to help explore and understand the composition and function of these... The internal structures of cells as the basic units of life are a major wonder of the microscopic world.Cellular images provide an intriguing window to help explore and understand the composition and function of these structures.Scientific imagery combined with artistic expression can further expand the potential of imaging in educational dissemination and interdisciplinary applications. 展开更多
关键词 interdisciplinary applications artistic expression diffusion model explore understand composition function cellular images educational dissemination style transfer internal structures
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Analysis of the optical quality by determining the modulation transfer function for anterior corneal surface in myopes 被引量:6
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作者 Yan-Zhen Zheng, Yao-Yu Li 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2012年第2期196-201,共6页
AIM: To describe the characteristics of modulation transfer function (MTF) of anterior corneal surface, and obtain the the normal reference range of MTF at different spatial frequencies and optical zones of the anteri... AIM: To describe the characteristics of modulation transfer function (MTF) of anterior corneal surface, and obtain the the normal reference range of MTF at different spatial frequencies and optical zones of the anterior corneal surface in myopes. METHODS: Four hundred eyes from 200 patients were examined under SIRIUS corneal topography system. Phoenis analysis software was applied to simulate the MTF curves of anterior corneal surface at vertical and horizontal meridians at the 3, 4, 5, 6, 7mm optical zones of cornea. The MTF values at spatial frequencies of 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60 cycles/degree (c/d) were selected. RESULTS: The MTF curve of anterior corneal surface decreased rapidly from low to intermediate frequency (0-15cpd) at various optical zones of cornea, the value decreased to 0 slowly at higher frequency (>15cpd). With the increase of the optical zones of cornea, MTF curve decreased gradually. 3) In the range of 3 mm- 6 mm optical zones of the cornea, the MTF values measured at horizontal meridian were greater than the corresponding values at horizontal meridian of each spatial frequency, the difference was statistically significant (P<0.05). At 7 mm optical zones of cornea, the MTF values measured at horizontal meridian were less than the corresponding values at vertical meridian at 10-60 spatial frequencies (cpd), and the difference was statistically significant in 25, 30, 35, 40, 45, 50 cpd(P<0.05). CONCLUSION: MTF can be used to describe the imaging quality of optical systems at anterior corneal surface objectively in detail. 展开更多
关键词 modulation transfer function optical quality CORNEA point spread function optical transfer function phase transfer function
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Temperature and Water Vapor Weighting Functions from Radiative Transfer Equation with Surface Emissivity and Solar Reflectivity 被引量:11
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作者 李俊 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1994年第4期421-426,共6页
Linearization of Radiative Transfer Equation (RTE) is the key step in physical retrieval of atmospheric temperature and moisture profiles from InfRared (IR) sounder observations. In this paper, the successive forms of... Linearization of Radiative Transfer Equation (RTE) is the key step in physical retrieval of atmospheric temperature and moisture profiles from InfRared (IR) sounder observations. In this paper, the successive forms of temperature and water vapor mixing ratio component weighting functions are derived by applying one term variation method to RTE with surface emissivity and solar reflectivity contained. Retrivals of temperature and water vapor mixing ratio profiles from simulated Atmospheric Infrared Sounder (AIRS) observations with surface emissivity and solar reflectivity are presented. 展开更多
关键词 Radiative transfer Equation Weighting function RETRIEVAL
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Transfer function measurement for the SSRF SRF system 被引量:2
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作者 Yang-Yang Xia Zhen-Tang Zhao +5 位作者 Yu-Bin Zhao Xiang Zheng Kai Xu Zhi-Gang Zhang Shen-Jie Zhao Qiang Chang 《Nuclear Science and Techniques》 SCIE CAS CSCD 2019年第6期129-137,共9页
A digital transfer function measurement system has been embedded in the low-level radio frequency (LLRF) system of the storage ring of the Shanghai Synchrotron Radiation Facility. The measurement results indicate that... A digital transfer function measurement system has been embedded in the low-level radio frequency (LLRF) system of the storage ring of the Shanghai Synchrotron Radiation Facility. The measurement results indicate that the decreased control accuracy at high current is primarily owing to ripples from the high-voltage power supply, the transient beam loading effect, and the digital aliasing effect. The current LLRF algorithm is not able to suppress these disturbances. 展开更多
关键词 transfer function RIPPLES of HVPS TRANSIENT BEAM LOADING effect
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Repetitive PD control strategy with inverse transfer function compensation for CVCF inverter 被引量:2
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作者 ShanxuDUAN 《控制理论与应用(英文版)》 EI 2004年第2期121-125,共5页
A novel repetitive control strategy for the output waveform of single-phase CVCF inverters is presented. In this scheme, the inverse transfer function of inverter is used as a compensator to obtain stable and satisfy ... A novel repetitive control strategy for the output waveform of single-phase CVCF inverters is presented. In this scheme, the inverse transfer function of inverter is used as a compensator to obtain stable and satisfy harmonic rejection. Besides, PD controller is adopted to improve transient performance. Simulation and experimental results, which are gotten from a DSP-based 400Hz, 5.5KW inverter, indicate that the proposed control scheme can achieve not only low THD during steady-state operation but also fast transient response during load step change. 展开更多
关键词 INVERTER Inverse transfer function Repetitive control PD control
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Modulation transfer function characteristic of uniform-doping transmission-mode GaAs/GaAlAs photocathode 被引量:2
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作者 任玲 常本康 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第8期398-402,共5页
The resolution characteristic can be obtained by the modulation transfer function (MTF) of a GaAs/GaA1As photocathode. After establishing the theoretical model of GaAs(100)-oriented atomic configuration and the fo... The resolution characteristic can be obtained by the modulation transfer function (MTF) of a GaAs/GaA1As photocathode. After establishing the theoretical model of GaAs(100)-oriented atomic configuration and the formula for the ionized impurity scattering of the non-equilibrium carriers, this paper calculates the trajectories of photoelectrons in a photocathode. Thus the distribution of photoelectron spots on the emit-face is obtained, which is namely the point spread function. The MTF is obtained by Fourier transfer of the line spread function obtained from the point spread function. The MTF obtained from these calculations is shown to depend heavily on the electron diffusion length, and enhanced considerably by decreasing the electron diffusion length and increasing the doping concentration. Furthermore, the resolution is enhanced considerably by increasing the active-layer thickness, especially at high spatial frequencies. The best spatial resolution is 860 lp/mm, for the GaAs photocathode of doping concentration 1 ×10^19 cm 3 electron diffusion length 3.6 μm and the active-layer thickness 2 μm, under the 633-nm light irradiated. This research will contribute to the future improvement of the cathode's resolution for preparing a high performance GaAs photocathode, and improve the resolution of a low light level image intensifier. 展开更多
关键词 GaAs/GaAlAs photocathode uniform-doping modulation transfer function spatial res-olution
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Influence of heme oxygenase-1 gene transfer on the viability and function of rat islets in in vitro culture 被引量:6
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作者 Xiao-Bo Chen Yong-Xiang Li +4 位作者 Yang Jiao Wei-Ping Dong Ge Li Jing Chen Jian-Ming Tan 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第7期1053-1059,共7页
AIM. To investigate the influence of heme oxygenase-1 (HO-1) gene transfer on the viability and function of cultured rat islets in vitro. METHODS: Islets were isolated from the pancreata of Sprague-Dawley rats by i... AIM. To investigate the influence of heme oxygenase-1 (HO-1) gene transfer on the viability and function of cultured rat islets in vitro. METHODS: Islets were isolated from the pancreata of Sprague-Dawley rats by intraductal collagenase digestion, and purified by discontinuous Ficoll density gradient centrifugation. Purified rat islets were transfected with adenoviral vectors containing human HO-1 gene (Ad- HO-1) or enhanced green fluorescent protein gene (Ad- EGFP), and then cultured for seven days. Transfection was confirmed by fluorescence microscopy and Western blot. Islet viability was evaluated by acridine orange/ propidium iodide fluorescent staining. Glucose-stimulated insulin release was detected using insulin radioimmunoassay kits and was used to assess the function of islets. Stimulation index (SI) was calculated by dividing the insulin release upon high glucose stimulation by the insulin release upon low glucose stimulation. RESULTS: After seven days culture, the viability of cultured rat islets decreased significantly (92% ± 6% vs 52% ± 13%, P 〈 0.05), and glucose-stimulated insulin release also decreased significantly (6.47 ± 0.55 mIU/ L/30IEO vs 4.57 ± 0.40 mIU/L/3OIEO., 14.93 ± 1.17 mIU/L/30IEQ vs 9.63 ± 0.71 mIU/L/30IEQ, P 〈 0.05). Transfection of rat islets with adenoviral vectors at an 1±10 of 20 was efficient, and did not impair islet function. At 7 d post-transfection, the viability of Ad-HO-1 transfected islets was higher than that of control islets(71% ± 15% vs 52% ± 13%, P 〈 0.05). There was no significant difference in insulin release upon low glucose stimulation (2.8 mmol/L) among Ad-HO-1 transfected group, Ad-EGFP transfected group, and control group (P 〉 0.05), while when stimulated by high glucose (16.7 mmol/L) solution, insulin release in Ad-HO-1 transfected group was significantly higher than that in Ad-EGFP transfected group and control group, respectively (12.50 ±2.17 mIU/L/30IEQ vs 8.87 ± 0.65 mIU/L/30IEQ, 12.50 ± 2.17 mIU/L/30IEQ vs 9.63 ± 0.71 mIU/L/30IEQ, P 〈 0.05). The SI of Ad-HO-1 transfected group was also significantly higher than that of Ad-EGFP transfected group and control group, respectively (2.21 ± 0.02 vs 2.08 ± 0.05; 2.21 ± 0.02 vs 2.11 ± 0.03, P 〈 0.05). CONCLUSION: The viability and function of rat islets decrease over time in in vitro culture, and heine oxygenase-1 gene transfer could improve the viability and function of cultured rat islets. 展开更多
关键词 Islet viability Islet function Heineoxygenase-1 Gene transfer Adenoviral vectors
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A hardening load transfer function for rock bolts and its calibration using distributed fiber optic sensing 被引量:4
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作者 Assaf Klar Ori Nissim Itai Elkayam 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第11期2816-2830,共15页
Confinement of rock bolts by the surrounding rock formation has long been recognized as a positive contributor to the pull-out behavior,yet only a few experimental works and analytical models have been reported,most o... Confinement of rock bolts by the surrounding rock formation has long been recognized as a positive contributor to the pull-out behavior,yet only a few experimental works and analytical models have been reported,most of which are based on the global rock bolt response evaluated in pull-out tests.This paper presents a laboratory experimental setup aiming to capture the rock formation effect,while using distributed fiber optic sensing to quantify the effect of the confinement and the reinforcement pull-out behavior on a more local level.It is shown that the behavior along the sample itself varies,with certain points exhibiting stress drops with crack formation.Some edge effects related to the kinematic freedom of the grout to dilate are also observed.Regardless,it was found that the mid-level response is quite similar to the average response along the sample.The ability to characterize the variation of the response along the sample is one of the many advantages high-resolution fiber optic sensing allows in such investigations.The paper also offers a plasticity-based hardening load transfer function,representing a"slice"of the anchor.The paper describes in detail the development of the model and the calibration/determination of its parameters.The suggested model captures well the coupled behavior in which the pull-out process leads to an increase in the confining stress due to dilative behavior. 展开更多
关键词 Rock bolts Distributed fiber optic sensing Pull-out tests Load transfer function Hardening model
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Spectrum Characteristics and Transfer Function of the Hydrograph of the Deep Aqueous System 被引量:1
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作者 Chen Baoren, Liu Shuyun, Earth Sciences Dept., Nanjing University, Nanjing, Jiangsu, China Jin Peikang Geological Dept., Tulane University, New Orleans, LA 70118, U.S.A. and Dong Shouyu Hebei Province Seismological Bureau, Shijiazhuang, Hebei, China 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1993年第4期453-464,共12页
The fluctuation of most of the hydrograph in the deep aqueous system records the fluid pulsation in lithosphere and variation of the earth's crust. Many observations have verified that groundwater is an ideal info... The fluctuation of most of the hydrograph in the deep aqueous system records the fluid pulsation in lithosphere and variation of the earth's crust. Many observations have verified that groundwater is an ideal information carrier of the crust. In this paper, the series of input (precipitation, air pressure, Earth tide etc.) and output (water level, artesian flow) of the deep aqueous system are studied by using the spectrum analysis and system theory. The application concepts of transfer function and the spectral structure of the hydrograph enrich the knowledge of the deep aqueous system. Two typical spectral structures of the hydrograph of the deep aqueous system are obtained by comparing with many water-bearing systems of the Jizhong depression. One is from well Ma-17 and the other is from the well Xinze-5. Finally, the physical models of forming the spectrum of the hydrograph are constructed on the basis of the spectrum research on the deep aqueous system. 展开更多
关键词 deep aqueous system HYDROGRAPH transfer function
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Establishment of a diatom-total phosphorus transfer function for lakes on the Songnen Plain in northeast China 被引量:2
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作者 SUI Fengyang ZANG Shuying +2 位作者 FAN Yawen LU Xinxin HUI Hongkuan 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2020年第6期1771-1786,共16页
To understand the relationship between planktonic diatoms and environmental variables in the lakes on the Songnen Plain,northeast(NE)China,we investigated water quality and planktonic diatoms from 71 sampling points i... To understand the relationship between planktonic diatoms and environmental variables in the lakes on the Songnen Plain,northeast(NE)China,we investigated water quality and planktonic diatoms from 71 sampling points in 27 lakes,based on which Canonical Correspondence Analysis(CCA)was conducted.The result show that planktonic diatoms displayed certain responses to environment gradients,and the total phosphorus(TP)explained the maximum variation of planktonic diatom species among the 15 environmental variables,suggesting that TP was the most important and significant environmental parameter affecting the distribution of diatom species.In addition,we established a diatom-total phosphorus transfer(DTPT)function,of which component 5 of the weighted averaging partial least squares regression(WAPLS)was chosen to and compared with a series of weighted average regression(WA)models and WA-PLS models.According to the jackknifing statistical test,the component 5 of WA-PLS models provided a lower root-mean-square error prediction(RMSEP=0.202)and a higher correlation coefficient between observation and prediction(R^2_Jack=0.759).After deletion of three outliers,the root-mean-square error prediction of the DTPT function was reduced(RMSEP=0.169)while the correlation coefficient between observation and prediction was increased(R^2_Jack=0.823).Therefore,this DTPT function performed better than other regional TP models in the world.However,it remains demanding for expanding the background dataset to improve the prediction ability of the model. 展开更多
关键词 Songnen Plain DIATOM total phosphorus transfer function
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