Fixed-appliance technology is the most common and effective malocclusion orthodontic treatment method, and its key step is the bending of orthodontic archwire. The springback of archwire did not consider the movement ...Fixed-appliance technology is the most common and effective malocclusion orthodontic treatment method, and its key step is the bending of orthodontic archwire. The springback of archwire did not consider the movement of the stress-strain-neutral layer. To solve this problem, a spring- back calculation model for rectangular orthodontic archwire is proposed. A bending springback experiment is conducted using an orthodontic archwire bending springback mea- surement device. The springback experimental results show that the theoretical calculation results using the proposed model coincide better with the experimental testing results than when movement of the stress-strain-neutral layer was not considered. A bending experiment with rectangular orthodontic archwire is conducted using a robotic orthodontic archwire bending system. The patient expriment result show that the maximum and minimum error ratios of formed orthodontic archwire parameters are 22.46% and 10.23% without considering springback and are decreased to 11.35% and 6.13% using the proposed model. The proposed springback calculation model, which considers the move- ment of the stress-strain-neutral layer, greatly improves the orthodontic archwire bending precision.展开更多
A Yarge-pore ECNU-19 material with unique pore system consisting of 12-ring （12R） pore channels intersected by 8R channels was post-synthesized via interlayer-expansion of HUS-2 lameliar silicate with silylating age...A Yarge-pore ECNU-19 material with unique pore system consisting of 12-ring （12R） pore channels intersected by 8R channels was post-synthesized via interlayer-expansion of HUS-2 lameliar silicate with silylating agent of 1,3-dimethyltetramethoxydisiloxane （DMTMDS）. In consideration of the fact that the HUS-2 precursor possessed a special structure with a malposition of the neighboring layers as well as silicon vacancies on layer surface, a ＂detemplating disassembly - intercalation reassembly - silylation＂ strategy was proposed to realize a successful interlayer-expansion and structural amending. An acid treatment was firstly performed to remove a part of the structure-directing agent molecules, which favored the following intercalation by bulk organic species. The intercalation not only rearranged the relative position of up-down layers but also provided enough interlayer space for the insertion of dimeric silane molecules. Two -OH groups attached to one silicon atom of the silane molecule reacted with two close silanols on the up-surface layer, while the other two -OH groups condensed with two silanols on the down-surface layer, which then connected the two layers via -Si-O-Si- pillars and constructed new 22R pores along o axis and 8R pores along c axis, respectively.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.51205093,61403222)China Postdoctoral Science Foundation(Grant No.2016M591538)+1 种基金Heilongjiang Postdoctoral Science Foundation(Grant No.LBH-Z16091)Science Funds for the Young Innovative Talents of Harbin University of Science and Technology(Grant No.201509)
文摘Fixed-appliance technology is the most common and effective malocclusion orthodontic treatment method, and its key step is the bending of orthodontic archwire. The springback of archwire did not consider the movement of the stress-strain-neutral layer. To solve this problem, a spring- back calculation model for rectangular orthodontic archwire is proposed. A bending springback experiment is conducted using an orthodontic archwire bending springback mea- surement device. The springback experimental results show that the theoretical calculation results using the proposed model coincide better with the experimental testing results than when movement of the stress-strain-neutral layer was not considered. A bending experiment with rectangular orthodontic archwire is conducted using a robotic orthodontic archwire bending system. The patient expriment result show that the maximum and minimum error ratios of formed orthodontic archwire parameters are 22.46% and 10.23% without considering springback and are decreased to 11.35% and 6.13% using the proposed model. The proposed springback calculation model, which considers the move- ment of the stress-strain-neutral layer, greatly improves the orthodontic archwire bending precision.
文摘A Yarge-pore ECNU-19 material with unique pore system consisting of 12-ring （12R） pore channels intersected by 8R channels was post-synthesized via interlayer-expansion of HUS-2 lameliar silicate with silylating agent of 1,3-dimethyltetramethoxydisiloxane （DMTMDS）. In consideration of the fact that the HUS-2 precursor possessed a special structure with a malposition of the neighboring layers as well as silicon vacancies on layer surface, a ＂detemplating disassembly - intercalation reassembly - silylation＂ strategy was proposed to realize a successful interlayer-expansion and structural amending. An acid treatment was firstly performed to remove a part of the structure-directing agent molecules, which favored the following intercalation by bulk organic species. The intercalation not only rearranged the relative position of up-down layers but also provided enough interlayer space for the insertion of dimeric silane molecules. Two -OH groups attached to one silicon atom of the silane molecule reacted with two close silanols on the up-surface layer, while the other two -OH groups condensed with two silanols on the down-surface layer, which then connected the two layers via -Si-O-Si- pillars and constructed new 22R pores along o axis and 8R pores along c axis, respectively.
