BACKGROUND Orthodontic treatment for open bite and crossbite cases is always challenging.In this paper,we demonstrate a skeletal class III patient with anterior open bite and crossbite whose problem was successfully c...BACKGROUND Orthodontic treatment for open bite and crossbite cases is always challenging.In this paper,we demonstrate a skeletal class III patient with anterior open bite and crossbite whose problem was successfully corrected with improved super-elastic Ti-Ni alloy wire(ISW).CASE SUMMARY A 19 years old male came to our clinic with a chief complaint of anterior open bite and crossbite and not able to chew food well.Clinical examination revealed an angle class III malocclusion with anterior open bite,crossbite and spaced arch.Ra-diographic and clinical examination showed a skeletal class III pattern.We used ISW to level the upper and lower arch and to correct the anterior open bite and crossbite.Intermaxillary elastics were also used to achieve a better interdigitation.Finally,adequate overbite,overjet and a desirable occlusion were achieved.The active treatment time took 2 years and 2 months.CONCLUSION In a case of class III angular malocclusion with open bite and crossbite in the ante-rior teeth,ideal results were achieved using the ISW technique and the patient was satisfied with the outcome.展开更多
Based on the experimental results of super-elastic NiTi alloy,a three-dimensional super-elastic constitutive model including both of stress-induced martensite transformation and plasticity is constructed in a framewor...Based on the experimental results of super-elastic NiTi alloy,a three-dimensional super-elastic constitutive model including both of stress-induced martensite transformation and plasticity is constructed in a framework of general inelasticity.In the proposed model,transformation hardening,reverse transformation of stress-induced martensite,elastic mismatch between the austenite and martensite phases,and temperature-dependence of transformation stress and elastic modulus of each phase are considered.The plastic yielding of martensite occurred under high stress is addressed by a bilinear isotropic hardening rule.Drucker-Prager-typed transformation surfaces are employed to describe the asymmetric behavior of NiTi alloy in tension and compression.The prediction capability of the proposed model is verified by comparing the simulated results with the correspondent experimental ones.Based on backward Euler's integration,a new expression of consistent tangent modulus is derived.The proposed model is then implemented into a finite element package ABAQUS by user-subroutine UMAT.Finally,the validity of such implementation was verified by some numerical samples.展开更多
Three-dimensional graphene-based aerogels have promising applications in oil adsorption and environmental restoration.However,current research of graphene-based aerogels is often hindered by high preparation cost,poor...Three-dimensional graphene-based aerogels have promising applications in oil adsorption and environmental restoration.However,current research of graphene-based aerogels is often hindered by high preparation cost,poor mechanical properties and low recycling efficiency.Here,superelastic graphene aerogel(SGA)was prepared through one-step freezing and twice hydrothermal reduction followed by drying under ambient pressure.The simple atmospheric drying provides a possibility for large-scale preparation of high performance graphene-based aerogels.The prepared SGA not only has the ability of highly repeatable compression rebound,but also exhibits excellent oil adsorption performance.And the overall performance of SGA is better than most of graphenebased aerogels prepared by freeze drying.After the SGA was cyclically compressed with 70%strain for 300 times,it can return to the original shape and height substantially.SGA retained about 90%of the initial adsorption capacity after 50 cycles of adsorption and compression regeneration for cyclohexane.展开更多
This study introduces a cut-to-fit methodology for customizing bulk aramid aerogels into form factors suitable for wearable energy storage.Owing to strong intercomponent bonds within aramid-based building blocks,it is...This study introduces a cut-to-fit methodology for customizing bulk aramid aerogels into form factors suitable for wearable energy storage.Owing to strong intercomponent bonds within aramid-based building blocks,it is possible to delaminate layered bulk aerogel into flexible and thinner sheets,enabling efficient mass production.This process allows for precise customization of aerogel dimensions,shape,and elasticity,ensuring high resilience to deformation along with excellent thermal and impact resistance.Incorporation of conductive carbon nanotubes on the surface significantly enhances electrical conductivity and multi-catalytic activity while retaining the inherent advantages of aramids.These advancements facilitate the use of flexible and conductive electrodes as air cathodes in solid-state zinc–air batteries(ZABs),which demonstrate superior cyclic performance and lifecycles exceeding 160 h.Furthermore,aramid-based packaging provides superior protection for pouch-type ZABs,ensuring a consistent power supply even in severe conditions.These batteries are capable of withstanding structural deformations and absorbing physical and thermal shocks,such as impacts and exposure to fire.Moreover,the innovative reassembly of custom-cut single-pouch cells into battery modules allows for enhanced power output,tailored to wearable applications.This highlights the potential of the technology for a wide array of wearable devices requiring dependable energy sources in demanding environments.展开更多
The key points to consider in determining the effectiveness of using structural isolation with shape memory alloys （SMA） are the constitutive model, the SMA isolation device and the analysis method. In this paper, a...The key points to consider in determining the effectiveness of using structural isolation with shape memory alloys （SMA） are the constitutive model, the SMA isolation device and the analysis method. In this paper, a simplified constitutive model based on the classic theory of plasticity is proposed to simulate the behavior of the superelasticity of the SMA, in which the martensite volume fraction is considered as one of the state variables. Comparisons between simulation results and experimental results are made and indicate that the proposed constitutive model yields stress-strain curves that are in good agreement with the experimental ones. Thus, the proposed model can correctly simulate the yield mechanism and energy dissipation capacity of the SMA. Next, in order to make full use of the superelasticity of SMA, a new SMA isolator composed of pre-tensioned SMA bars is presented. Then, a finite element analytical model is established to simulate the behavior of the SMA isolator according to its configuration and simplified constitutive model. Finally, a simplified design method for long-span structures installed with SMA isolators is proposed, which is further used to investigate the isolation effects of a space grid structure. Results show that the SMA isolator can reduce the seismic responses of the structure effectively, which indicates the effectiveness of the proposed SMA isolation method.展开更多
文摘BACKGROUND Orthodontic treatment for open bite and crossbite cases is always challenging.In this paper,we demonstrate a skeletal class III patient with anterior open bite and crossbite whose problem was successfully corrected with improved super-elastic Ti-Ni alloy wire(ISW).CASE SUMMARY A 19 years old male came to our clinic with a chief complaint of anterior open bite and crossbite and not able to chew food well.Clinical examination revealed an angle class III malocclusion with anterior open bite,crossbite and spaced arch.Ra-diographic and clinical examination showed a skeletal class III pattern.We used ISW to level the upper and lower arch and to correct the anterior open bite and crossbite.Intermaxillary elastics were also used to achieve a better interdigitation.Finally,adequate overbite,overjet and a desirable occlusion were achieved.The active treatment time took 2 years and 2 months.CONCLUSION In a case of class III angular malocclusion with open bite and crossbite in the ante-rior teeth,ideal results were achieved using the ISW technique and the patient was satisfied with the outcome.
基金supported by the New Century Excellent Talents in University(No.NCET05-0796)National Natural Science Foundation of China(No.50625515)the Innovation Foundation of Southwest Jiaotong University(2008)
文摘Based on the experimental results of super-elastic NiTi alloy,a three-dimensional super-elastic constitutive model including both of stress-induced martensite transformation and plasticity is constructed in a framework of general inelasticity.In the proposed model,transformation hardening,reverse transformation of stress-induced martensite,elastic mismatch between the austenite and martensite phases,and temperature-dependence of transformation stress and elastic modulus of each phase are considered.The plastic yielding of martensite occurred under high stress is addressed by a bilinear isotropic hardening rule.Drucker-Prager-typed transformation surfaces are employed to describe the asymmetric behavior of NiTi alloy in tension and compression.The prediction capability of the proposed model is verified by comparing the simulated results with the correspondent experimental ones.Based on backward Euler's integration,a new expression of consistent tangent modulus is derived.The proposed model is then implemented into a finite element package ABAQUS by user-subroutine UMAT.Finally,the validity of such implementation was verified by some numerical samples.
基金the financial support of National Natural Science Foundation of China (22078366)
文摘Three-dimensional graphene-based aerogels have promising applications in oil adsorption and environmental restoration.However,current research of graphene-based aerogels is often hindered by high preparation cost,poor mechanical properties and low recycling efficiency.Here,superelastic graphene aerogel(SGA)was prepared through one-step freezing and twice hydrothermal reduction followed by drying under ambient pressure.The simple atmospheric drying provides a possibility for large-scale preparation of high performance graphene-based aerogels.The prepared SGA not only has the ability of highly repeatable compression rebound,but also exhibits excellent oil adsorption performance.And the overall performance of SGA is better than most of graphenebased aerogels prepared by freeze drying.After the SGA was cyclically compressed with 70%strain for 300 times,it can return to the original shape and height substantially.SGA retained about 90%of the initial adsorption capacity after 50 cycles of adsorption and compression regeneration for cyclohexane.
基金supported by‘Regional Innovation Strategy(RIS)’through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(MOE)(2021RIS-002)supported by NRF grant funded by Ministry of Science,ICT and Future Planning(No.NRF-2018R1C1B6005009,NRF-2021R1C1C1012676,and 2009-0082580).
文摘This study introduces a cut-to-fit methodology for customizing bulk aramid aerogels into form factors suitable for wearable energy storage.Owing to strong intercomponent bonds within aramid-based building blocks,it is possible to delaminate layered bulk aerogel into flexible and thinner sheets,enabling efficient mass production.This process allows for precise customization of aerogel dimensions,shape,and elasticity,ensuring high resilience to deformation along with excellent thermal and impact resistance.Incorporation of conductive carbon nanotubes on the surface significantly enhances electrical conductivity and multi-catalytic activity while retaining the inherent advantages of aramids.These advancements facilitate the use of flexible and conductive electrodes as air cathodes in solid-state zinc–air batteries(ZABs),which demonstrate superior cyclic performance and lifecycles exceeding 160 h.Furthermore,aramid-based packaging provides superior protection for pouch-type ZABs,ensuring a consistent power supply even in severe conditions.These batteries are capable of withstanding structural deformations and absorbing physical and thermal shocks,such as impacts and exposure to fire.Moreover,the innovative reassembly of custom-cut single-pouch cells into battery modules allows for enhanced power output,tailored to wearable applications.This highlights the potential of the technology for a wide array of wearable devices requiring dependable energy sources in demanding environments.
基金National Natural Science Foundation of China Under Grant No. 50725828 & No. 50808041Scientific Research Foundation of Graduate School of Southeast University Under Grant No. YBJJ1006Teaching and Research Foundation for Excellent Young Teacher of Southeast University
文摘The key points to consider in determining the effectiveness of using structural isolation with shape memory alloys （SMA） are the constitutive model, the SMA isolation device and the analysis method. In this paper, a simplified constitutive model based on the classic theory of plasticity is proposed to simulate the behavior of the superelasticity of the SMA, in which the martensite volume fraction is considered as one of the state variables. Comparisons between simulation results and experimental results are made and indicate that the proposed constitutive model yields stress-strain curves that are in good agreement with the experimental ones. Thus, the proposed model can correctly simulate the yield mechanism and energy dissipation capacity of the SMA. Next, in order to make full use of the superelasticity of SMA, a new SMA isolator composed of pre-tensioned SMA bars is presented. Then, a finite element analytical model is established to simulate the behavior of the SMA isolator according to its configuration and simplified constitutive model. Finally, a simplified design method for long-span structures installed with SMA isolators is proposed, which is further used to investigate the isolation effects of a space grid structure. Results show that the SMA isolator can reduce the seismic responses of the structure effectively, which indicates the effectiveness of the proposed SMA isolation method.
