The Deformation Analysis of the 3D Alignment Control Network Based on the Multiple Congruence Models

In the construction and maintenance of particle accelerators,all the accelerator elements should be installed in the same coordinate system,only in this way could the devices in the actual world be consistent with the design drawings.However,with the occurrence of the movements of the reinforced concrete cover plates at short notice or building deformations in the long term,the control points upon the engineering structure will be displaced,and the fitness between the subnetwork and the global control network may be irresponsible.Therefore,it is necessary to evaluate the deformations of the 3D alignment control network.Different from the extant investigations,in this paper,to characterize the deformations of the control network,all of the congruent models between the points measured in different epochs have been identified,and the congruence model with the most control points is considered as the primary or fundamental model,the remaining models are recognized as the additional ones.Furthermore,the discrepancies between the primary S-transformation parameters and the additional S-transformation parameters can reflect the relative movements of the additional congruence models.Both the iterative GCT method and the iterative combinatorial theory are proposed to detect multiple congruence models in the control network.Considering the actual work of the alignment,it is essential to identify the competitive models in the monitoring network,which can provide us a hint that,even the fitness between the subnetwork and the global control network is good,there are still deformations which may be ignored.The numerical experiments show that the suggested approaches can describe the deformation of the 3D alignment control network roundly.

Aligned carbon nanostructures based 3D electrodes for energy storage

Electrochemical energy storage systems with high specific energy and power as well as long cyclic stability attract increasing attention in new energy technologies. The principles for rational design of electrodes are discussed to reduce the activation, concentration, and resistance overpotentials and improve the active ma- terial efficiency in order to simultaneously achieve high specific energy and power. Three dimensional （3D） nanocomposites are currently considered as promising electrode materials due to their large surface area, reduced electronic and ionic diffusion distances, and synergistic effects. This paper reviews the most recent progress on the synthesis and application of 3D thin film nanoelectrode arrays based on aligned carbon nan- otubes （ACNTs） directly grown on metal foils for energy storages and special attentions are paid on our own representative works. These novel 3D nanoelectrode arrays on metal foil exhibit improved electrochemical performances in terms of specific energy, specific power and cyclic stability due to their unique structures. In this active materials coated ACNTs over conductive substrate structures, each component is tailored to address a different demand. The electrochemical active material is used to store energy, while the ACNTs are employed to provide a large surface area to support the active material and nanocable arrays to facilitate the electron transport. The thin film of active materials can not only reduce ion transport resistance by shorten- ing the diffusion length but also make the film elastic enough to tolerate significant volume changes during charge and discharge cycles. The conductive substrate is used as the current collector and the direct contact of the ACNT arrays with the substrate reduces significantly the contact resistance. The principles obtained from ACNT based electrodes are extended to aligned graphene based electrodes. Similar improvements have been achieved which confirms the reliability of the principles obtained. In addition, we also discuss and view the ongoing trends in development of aligned carbon nanostructures based electrodes for energy storage.

3D vertically aligned microchannel structure to enhance piezoelectric energy harvesting performance of PZT/PVDF&CNTs piezoelectric composites

Piezoelectric energy harvesters(PEHs)have attracted significant attention with the ability of converting mechanical energy into electrical energy and power the self-powered microelectronic components.Generally,material's superior energy harvesting performance is closely related to its high transduction coefficient(d_(33)×g_(33)),which is dependent on higher piezoelectric coefficient d33 and lower dielectric constantεr of materials.However,the high d33 and lowεr are difficult to be simultaneously achieved in piezoelectric ceramics.Herein,lead zirconate titanate(PZT)based piezoelectric composites with vertically aligned microchannel structure are constructed by phase-inversion method.The polyvinylidene fluoride(PVDF)and carbon nanotubes(CNTs)are mixed as fillers to fabricate PZT/PVDF&CNTs composites.The unique structure and uniformly distributed CNTs network enhance the polarization and thus improve the d33.The PVDF filler effectively reduce theεr.As a consequence,the excellent piezoelectric coefficient(d_(33)=595 pC/N)and relatively low dielectric constant(ε_(r)=1,603)were obtained in PZT/PVDF&CNTs composites,which generated an ultra-high d_(33)×g_(33) of 24,942×10^(−15) m^(2)/N.Therefore,the PZT/PVDF&CNTs piezoelectric composites achieve excellent energy harvesting performance(output voltage:66 V,short current:39.22μA,and power density:1.25μW/mm^(2)).Our strategy effectively boosts the performance of piezoelectric-polymer composites,which has certain guiding significance for design of energy harvesters.