检索结果-南通市图书馆

Structural Properties of Ions and Polyelectrolytes in Aqueous Solutions under External Electric Fields:The Sign Effect

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第9期42卷 1341-1352,I0007页

作者： cheng-Jiang Lin Jun-Jun Wang Yuan Jiang Shu-Li Chen Hong-Fei Li wen-Han Zhao Qing-Rong Huang Chang-Ru Rong Xiao-zheng Duan State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China National Key Laboratory of Advanced Vehicle Integration and Control China FAW Group Co.Ltd.Changchun130013China State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai200438China Department of Food Science Rutgers University65 Dudley RoadNew BrunswickNew Jersey08901USA

We utilize molecular dynamics simulations to investigate the microstructures of ions and polyelectrolytes in aqueous solutions under external electric *** focusing on the multi-body interactions between ionic components and H_(2)O molecules,as well as their responses to the external electric fields,we clarify several nontrivial molecular features of the ionic and polyelectrolyte solutions,such as the solvations of cations and anions,clustering of the ions,and dispersions/aggregations of polyelectrolyte chains,as well as the corresponding responses of H_(2)O molecules in these *** simulations illustrate the variations in structures of ionic solutions caused by reversing the charge sign of the ions,and elucidate the disparity in structures between anionic and cationic polyelectrolyte solutions in the presence of the external electric *** work clarifies the mechanism for the alternations in complex multi-body interactions in aqueous solutions caused by the application electric field,which can contribute to the fundamental understanding of the physical and chemical natures of ion-containing and charged polymeric systems.

关键词： Polyelectrolyte Ions Aqueous solutions External electric fields Asymmetric dipole

Small tracking error correction for moving targets of intelligent electro-optical detection systems

在线全文

学校读者我要写书评

暂无评论

Frontiers of Mechanical Engineering 2024年第2期19卷 29-44页

作者： cheng SHEN Zhijie wen wenliang ZHU Dapeng FAN Mingyuan LING College of Intelligence Science and Technology National University of Defense TechnologyChangsha 410073China

Small tracking error correction for electro-optical systems is essential to improve the tracking precision of future mechanical and defense *** threats,such as“low,slow,and small(LSS)”moving targets,pose increasing challenges to *** core goal of this work is to address the issues,such as small tracking error correction and aiming control,of electro-optical detection systems by using mechatronics drive modeling,composite velocity–image stability control,and improved interpolation filter design.A tracking controller delay prediction method for moving targets is proposed based on the Euler transformation model of a two-axis,two-gimbal cantilever beam coaxial *** tracking error formation is analyzed in detail to reveal the scientific mechanism of composite control between the tracking controller’s feedback and the motor’s velocity–stability *** improved segmental interpolation filtering algorithm is established by combining line of sight(LOS)position correction and multivariable typical tracking fault ***,a platform with 2 degrees of freedom is used to test the *** LSS moving target shooting object with a tracking distance of S=100 m,target board area of A=1 m^(2),and target linear velocity of v=5 m/s is *** show that the optimal method’s distribution probability of the tracking error in a circle with a radius of 1 mrad is 66.7%,and that of the traditional method is 41.6%.Compared with the LOS shooting accuracy of the traditional method,the LOS shooting accuracy of the optimized method is improved by 37.6%.

关键词： electro-optical detection system small tracking error moving target visual servo aiming contro

Enhancing Tropical Cyclone Intensity Estimation from Satellite Imagery through Deep Learning Techniques

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Meteorological Research 2024年第4期38卷 652-663页

作者： wen YANG Jianfang FEI Xiaogang HUANG Juli DING Xiaoping cheng College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410008 Beijing Institute of Applied Meteorology Beijing 100029

This study first utilizes four well-performing pre-trained convolutional neural networks(CNNs) to gauge the intensity of tropical cyclones(TCs) using geostationary satellite infrared(IR) *** models are trained and tested on TC cases spanning from 2004 to 2022 over the western North Pacific *** enhance the models performance,various techniques are employed,including fine-tuning the original CNN models,introducing rotation augmentation to the initial dataset,temporal enhancement via sequential imagery,integrating auxiliary physical information,and adjusting *** optimized CNN model,i.e.,visual geometry group network(VGGNet),for TC intensity estimation is ultimately *** applied to the test data,the model achieves a relatively low mean absolute error(MAE) of 4.05 m s~(-1).To improve the interpretability of the model,the SmoothGrad combined with the Integrated Gradients approach is *** analyses reveal that the VGGNet model places significant emphasis on the distinct inner core region of a TC when estimating its ***,it partly takes into account the configuration of cloud systems as input features for the model,aligning well with meteorological *** several improvements made to this model's performance offer valuable insights for enhancing TC intensity forecasts through deep learning.

关键词： tropical cyclone intensity deep learning satellite imagery

Numerical investigation of the coupled aero-hydrodynamic performances of a semi-submersible floating offshore wind turbine with inclined columns

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2024年第2期36卷 316-330页

作者： Ying-jie Xue Xiao-long Yang Wei-wen Zhao De-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Offshore Oil Engineering Co.Ltd. Tianjin300461China

Numerical investigations of floating platforms with different outer column inclined angles under two operating conditions of regular wave and irregular wave are presented in this paper.A coupled aero-hydrodynamic computational fluid dynamics in-house solver FOWT-UALM-SJTU is applied for the ***,the validation for wave and wind generation are conducted to determine mesh distribution *** on these,the hydrodynamic motion response,aerodynamic performance and wake flow are analyzed to explore the impact of inclined *** spectral analysis on the motion response under wave action,discuss the aerodynamic attack angle and inflow wind velocity along the blade spanwise direction in detail,reveal different trends in wake development and *** results show that for the regular wave condition with the increase of inclined angles,the equilibrium position of surge motion is constantly rising,while pitch is *** maximum root mean square(rms)value occurs at angle=30°,compared with the original OC4 FOWT,the rms in power and thrust increase 0.35%,0.71%.And there are two low regions of attack angle and high regions of axial inflow velocity,corresponding to aerodynamic *** spectral analysis indicates that the natural frequency of pitch motion will increase with inclined ***,from the middle to far region of wake flow,the velocity recovery of FOWT with inclined angle will become faster,which is beneficial for downstream turbines to enhance more wind energy.

关键词： Floating offshore wind turbine numerical simulation aero-hydrodynamic coupled analysis floating platform with inclinedcolumns wake flow recovery

Numerical simulation of liquid sloshing in a spherical tank by MPS method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2024年第2期36卷 232-240页

作者： Cong-yi Huang Ji-fei Wang Wei-wen Zhao De-cheng Wan Computational Marine Hydrodynamic Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Shanghai Aerospace System Engineering Institute Shanghai201109China

This paper investigates the sloshing phenomena in a spherical liquid tank using the moving particle semi-implicit(MPS)method,a crucial study in fluid *** from previous research focused on rectangular or LNG tanks,this work explores the unique motion patterns inherent to spherical *** accuracy of our in-house MPS solver MLParticle-SJTU is validated against experimental data and finite volume method(FVM).And the MPS method reveals a closer alignment with experimental outcomes,which suggests that MPS method is particularly effective for modeling complex,non-linear fluid *** the fluid’s response to excitation at its natural frequency is simulated,showcasing vigorous sloshing and rotational *** analyses of the fluid motion are conducted by drawing streamline diagrams,velocity vector diagrams,and vorticity *** fluid’s motion response is explored using both time-domain and frequency-domain curves of the fluid centroid,as well as the sloshing force.

关键词： Moving particle semi-implicit(MPS)method spherical tank liquid sloshing model experiment

Conceptual design of a 714-MHz RFQ for compact proton injectors and development of a new tuning algorithm on its aluminium prototype

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第1期35卷 45-58页

作者： Yi-Xing Lu wen-cheng Fang Yu-Sen Guo Zhen-Tang Zhao Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800China University of Chinese Academy of Sciences Beijing 101408China Shanghai Advanced Research Institute Chinese Academy of Sciences Shanghai 201204China Shanghai Key Laboratory of Cryogenics&Superconducting RF Technology Shanghai 201800China ShanghaiTech University Shanghai 201210China

Radio frequency quadrupoles(RFQs),which are crucial components of proton injectors,significantly affect the performance of proton accelerator *** RFQ with a high frequency of 714 MHz dedicated to compact proton injectors for medi-cal applications is designed in this *** RFQ is designed to accelerate proton beams from 50 keV to 4 MeV within a short length of 2 m and can be matched closely with the downstream drift tube linac to capture more particles through a preliminary *** develop an advanced RFQ,challenging techniques,including fabrication and tuning method,must be evaluated and verified using a *** aluminium prototype is derived from the conceptual design of the RFQ and then redesigned to confirm the radio frequency performance,fabrication procedure,and feasibility of the tuning ***,a new tuning algorithm based on the response matrix and least-squares method is developed,which yields favorable results based on the prototype,i.e.,the errors of the dipole and quadrupole components reduced to a low level after several tuning *** from the conceptual design and techniques obtained from the prototype,the formal mechanical design of the 2-m RFQ is ready for the next manufacturing step.

关键词： Compact proton injector RFQ IH-DTL High gradient Tuning

High temperature lubrication performance of chlorophenyl silicone oil

在线全文

学校读者我要写书评

暂无评论

Friction 2024年第8期12卷 1716-1727页

作者： Yan MENG Xiangli wen Jie cheng Pengpeng BAI Yonggang MENG Yu TIAN School of Mechanical and Electrical Engineering China University of Mining and Technology-BeijingBeijing 100083China Department of Mechanical Engineering State Key Laboratory of Tribology in Advanced EquipmentTsinghua UniversityBeijing 100084China

Most studies of liquid lubricants were carried out at temperatures below 200°***,the service temperature of lubricants for aerospace and aeroengine has reached above 300°*** order to investigate the friction mechanism and provide data for high temperature lubrication,the friction and wear properties of chlorophenyl silicone oil(CPSO)-lubricated M50 steel and Si3N4 friction pairs were investigated ***-on-disk experimental results show that the lubrication performance of CPSO varies significantly with *** 150°C,coefficient of friction(COF)remains at 0.13–0.15 after the short running-in stage(600 s),while the COF in the running-in stage is 0.2–*** 200°C and above,the running-in time is much longer(1,200 s),and the initial instantaneous maximum COF can reach *** this condition,the COF gradually decreases and finally stabilizes at around 0.16–0.17 *** phenomenon is mainly due to the different thickness of boundary adsorption *** importantly,the wear rate of M50 steel increases significantly with the temperature,while the wear rate barely changes at temperatures above 200°*** anti-wear mechanism is explained as tribochemical reactions are more likely to occur between CPSO and steel surface with the increased temperature,generating the FeCl2 protective film on the metal ***,FeCl2 tribochemical film improves the lubrication and anti-wear capacity of the *** high temperatures(200–350°C),FeCl2 film becomes thicker,and the contact region pressure becomes lower due to the larger wear scar size,so the wear rate growth of M50 steel is much smaller compared with that of low temperatures(22–150°C).The main findings in this study demonstrate that CPSO lubricant has good anti-wear and lubrication capacity,which is capable of working under temperatures up to 350°C.

关键词： chlorophenyl silicone oil(CPSO) liquid lubricant anti-wear high temperature

A Comparative Study on the Post-Buckling Behavior of Reinforced Thermoplastic Pipes(RTPs)Under External Pressure Considering Progressive Failure

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Ocean Engineering 2024年第2期38卷 233-246页

作者： DING Xin-dong WANG Shu-qing LIU wen-cheng YE Xiao-han College of Engineering Ocean University of ChinaQingdao 266100China Shandong Provincial Key Laboratory of Ocean Engineering Ocean University of ChinaQingdao 266100China Department of Marine Technology Norwegian University of Science and Technology(NTNU)Trondheim NO-7491Norway

The collapse pressure is a key parameter when RTPs are applied in harsh deep-water *** investigate the collapse of RTPs,numerical simulations and hydrostatic pressure tests are *** the numerical simulations,the eigenvalue analysis and Riks analysis are combined,in which the Hashin failure criterion and fracture energy stiffness degradation model are used to simulate the progressive failure of composites,and the“infinite”boundary conditions are applied to eliminate the boundary *** for the hydrostatic pressure tests,RTP specimens were placed in a hydrostatic chamber after filled with *** has been observed that the cross-section of the middle part collapses when it reaches the maximum *** collapse pressure obtained from the numerical simulations agrees well with that in the ***,the applicability of NASA SP-8007 formula on the collapse pressure prediction was also *** has a relatively greater difference because of the ignorance of the progressive failure of *** the parametric study,it is found that RTPs have much higher first-ply-failure pressure when the winding angles are between 50°and 70°.Besides,the effect of debonding and initial ovality,and the contribution of the liner and coating are also discussed.

关键词： reinforced thermoplastic pipes post-buckling behavior progressive failure of composites debonding initial ovality

Magnetic-field-assisted triboelectric nanogenerator for harvesting multi-directional wave energy

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第8期17卷 7144-7152页

作者： Mengru Ding Jianlong Wang Da Zhao Hengyu Li Xiaojun cheng Jianming wen Zhong Lin Wang Tinghai cheng Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing 101400China School of Nanoscience and Engineering University of Chinese Academy of SciencesBeijing 100049China Guangzhou Institute of Blue Energy Guangzhou 510555China College of Engineering Zhejiang Normal UniversityJinhua 321004China School of Materials Science and Engineering Georgia Institute of TechnologyAtlantaGA 30332-0245USA

Ocean wave energy is a significant and promising source of renewable ***,the energy harvesting is challenging due to the multi-directional nature of *** paper proposes a magnetic-field-assisted triboelectric nanogenerator(MFATENG)for harvesting multi-directional wave *** incorporating a magnetic field,the planar motion of the pendulum is converted into spatial motion,increasing the triggering of multilayered TENG(M-TENG)and enhancing the output energy of the *** results demonstrate that the output energy of the MFA-TENG is increased by 73%by utilizing the magnetic ***,a spring model based on the origami-structured M-TENG is established to analyze the effect of different equivalent stiffnesses on the performance of the M-TENG,aiming to obtain optimal output *** results showcase the impressive output performance of the M-TENG,generating outputs of 250 V,18μA,and 255 ***,the proposed MFA-TENG effectively harvests multi-directional wave energy under water-wave driven *** study significantly enhances the ability of the MFA-TENG to harvest multi-directional wave energy and presents a promising approach for self-powered marine monitoring in the future.

关键词： triboelectric nanogenerator magnetic-field-assisted spring model multi-directional wave energy