We fabricate and characterize Au nanoparticle-aggregated nanowires by using the nano meniscus-induced colloidal stacking method. The Au nanoparticle solution ejects with guidance of nanopipette/quartz tuning fork-base...We fabricate and characterize Au nanoparticle-aggregated nanowires by using the nano meniscus-induced colloidal stacking method. The Au nanoparticle solution ejects with guidance of nanopipette/quartz tuning fork-based atomic force microscope in ambient conditions, and the stacking particles form Au nanoparticle-aggregated nanowire while the nozzle retracts from the surface. Their mechanical properties with relatively low elastic modulus are in situ investigated by using the same apparatus.展开更多
The quality of the low frequency electromagnetic data is affected by the spike and the trend noises.Failure in removal of the spikes and the trends reduces the credibility of data explanation.Based on the analyses of ...The quality of the low frequency electromagnetic data is affected by the spike and the trend noises.Failure in removal of the spikes and the trends reduces the credibility of data explanation.Based on the analyses of the causes and characteristics of these noises,this paper presents the results of a preset statistics stacking method(PSSM)and a piecewise linear fitting method(PLFM)in de-noising the spikes and trends,respectively.The magnitudes of the spikes are either higher or lower than the normal values,which leads to distortion of the useful signal.Comparisons have been performed in removing of the spikes among the average,the statistics and the PSSM methods,and the results indicate that only the PSSM can remove the spikes successfully.On the other hand,the spectrums of the linear and nonlinear trends mainly lie in the low frequency band and can change the calculated resistivity significantly.No influence of the trends is observed when the frequency is higher than a certain threshold value.The PLSM can remove effectively both the linear and nonlinear trends with errors around 1% in the power spectrum.The proposed methods present an effective way for de-noising the spike and the trend noises in the low frequency electromagnetic data,and establish a research basis for de-noising the low frequency noises.展开更多
In this study, we collected 1156 broadband vertical components records at 22 digital seismic stations in Xinjiang region, Urumqi station, and 7 stations in the adjacent regions during the period of 1999-2003. The reco...In this study, we collected 1156 broadband vertical components records at 22 digital seismic stations in Xinjiang region, Urumqi station, and 7 stations in the adjacent regions during the period of 1999-2003. The records were firstly processed by the stacked spectral ratio method to obtain Q0 (Q at 1 Hz) and the frequency correlation factor η corresponding to each path. Based on the results, the distribution images of Q0 and η in 1°×1° grids for Xinjiang region were gained by the back-projection technique. The results indicate that Q0 is high (300-450) in the Tarim platform and marginal Siberian platform, while Q0 is low (150-250) in the southern regions as west Kunlun fold system and Songpan-Ganzi fold system. In the northern regions as Junggar fold system and Tianshan fold system, Q0 is also low (250-300) and η varies between 0.5 and 0.9.展开更多
Dielectric elastomers(DEs)have emerged as one of the most promising artificial muscle technologies,due to their exceptional properties such as large actuation strain,fast response,high energy density,and flexible proc...Dielectric elastomers(DEs)have emerged as one of the most promising artificial muscle technologies,due to their exceptional properties such as large actuation strain,fast response,high energy density,and flexible processibility for various configurations.Over the past two decades,researchers have been working on developing DE materials with improved properties and exploring innovative applications of dielectric elastomer actuators(DEAs).This review article focuses on two main topics:recent material innovation of DEs and development of multilayer stacking processes for DEAs,which are important to promoting commercialization of DEs.It begins by explaining the working principle of a DEA.Then,recently developed strategies for preparing new DE materials are introduced,including reducing mechanical stiffness,increasing dielectric permittivity,suppressing viscoelasticity loss,and mitigating electromechanical instability without pre-stretching.In the next section,different multilayer stacking methods for fabricating multilayer DEAs are discussed,including conventional dry stacking,wet stacking,a novel dry stacking method,and micro-fabrication-enabled stacking techniques.This review provides a comprehensive and up-to-date overview of recent developments in high-performance DE materials and multilayer stacking methods.It highlights the progress made in the field and also discusses potential future directions for further advancements.展开更多
基金supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No. 200983512)Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2013R1A6A3A03063900)the Brain Korea 21
文摘We fabricate and characterize Au nanoparticle-aggregated nanowires by using the nano meniscus-induced colloidal stacking method. The Au nanoparticle solution ejects with guidance of nanopipette/quartz tuning fork-based atomic force microscope in ambient conditions, and the stacking particles form Au nanoparticle-aggregated nanowire while the nozzle retracts from the surface. Their mechanical properties with relatively low elastic modulus are in situ investigated by using the same apparatus.
文摘The quality of the low frequency electromagnetic data is affected by the spike and the trend noises.Failure in removal of the spikes and the trends reduces the credibility of data explanation.Based on the analyses of the causes and characteristics of these noises,this paper presents the results of a preset statistics stacking method(PSSM)and a piecewise linear fitting method(PLFM)in de-noising the spikes and trends,respectively.The magnitudes of the spikes are either higher or lower than the normal values,which leads to distortion of the useful signal.Comparisons have been performed in removing of the spikes among the average,the statistics and the PSSM methods,and the results indicate that only the PSSM can remove the spikes successfully.On the other hand,the spectrums of the linear and nonlinear trends mainly lie in the low frequency band and can change the calculated resistivity significantly.No influence of the trends is observed when the frequency is higher than a certain threshold value.The PLSM can remove effectively both the linear and nonlinear trends with errors around 1% in the power spectrum.The proposed methods present an effective way for de-noising the spike and the trend noises in the low frequency electromagnetic data,and establish a research basis for de-noising the low frequency noises.
基金National Natural Science Foundation of China (49974012) and Joint Seismological Science Foundation of China (604004).
文摘In this study, we collected 1156 broadband vertical components records at 22 digital seismic stations in Xinjiang region, Urumqi station, and 7 stations in the adjacent regions during the period of 1999-2003. The records were firstly processed by the stacked spectral ratio method to obtain Q0 (Q at 1 Hz) and the frequency correlation factor η corresponding to each path. Based on the results, the distribution images of Q0 and η in 1°×1° grids for Xinjiang region were gained by the back-projection technique. The results indicate that Q0 is high (300-450) in the Tarim platform and marginal Siberian platform, while Q0 is low (150-250) in the southern regions as west Kunlun fold system and Songpan-Ganzi fold system. In the northern regions as Junggar fold system and Tianshan fold system, Q0 is also low (250-300) and η varies between 0.5 and 0.9.
基金This work is supported by the National Natural Science Foundation of China(No.T229722).
文摘Dielectric elastomers(DEs)have emerged as one of the most promising artificial muscle technologies,due to their exceptional properties such as large actuation strain,fast response,high energy density,and flexible processibility for various configurations.Over the past two decades,researchers have been working on developing DE materials with improved properties and exploring innovative applications of dielectric elastomer actuators(DEAs).This review article focuses on two main topics:recent material innovation of DEs and development of multilayer stacking processes for DEAs,which are important to promoting commercialization of DEs.It begins by explaining the working principle of a DEA.Then,recently developed strategies for preparing new DE materials are introduced,including reducing mechanical stiffness,increasing dielectric permittivity,suppressing viscoelasticity loss,and mitigating electromechanical instability without pre-stretching.In the next section,different multilayer stacking methods for fabricating multilayer DEAs are discussed,including conventional dry stacking,wet stacking,a novel dry stacking method,and micro-fabrication-enabled stacking techniques.This review provides a comprehensive and up-to-date overview of recent developments in high-performance DE materials and multilayer stacking methods.It highlights the progress made in the field and also discusses potential future directions for further advancements.