Worm grinding has been applied to manufacture gears to pursue high accuracy and fine surface finish.When the worm used to grind face gears is manufactured with multi-axis computer numerical control(CNC)machining,the m...Worm grinding has been applied to manufacture gears to pursue high accuracy and fine surface finish.When the worm used to grind face gears is manufactured with multi-axis computer numerical control(CNC)machining,the machining accuracy is usually improved by increasing the number of tool paths with more time cost.Differently,this work proposes a generated method to improve the efficiency by dressing the worm surface with only one path,and a closed-loop manufacturing process is applied to ensure the machining accuracy.According to an advanced geometric analysis,the worm surface is practically approximated as a swept surface generated by a planar curve.Meanwhile,this curve is applied as the profile of a dressing wheel,which is used to dress the worm surface.The practical machining is carried out in a CNC machine tool,which was originally used to grind helical gears.Finally,a closed-loop manufacturing process including machining,measurement,and modification is proposed to compensate the machining errors.The proposed method is validated with simulations and practical experiments.展开更多
In animals, signaling behavior is often context-dependent, with variation in the probability of emitting certain signals dependent on fitness advantages. Senders may adjust signaling rate depending on receiver identit...In animals, signaling behavior is often context-dependent, with variation in the probability of emitting certain signals dependent on fitness advantages. Senders may adjust signaling rate depending on receiver identity, presence of audiences, or noise masking the signal, all of which can affect the benefits and costs of signal production. In the cooperative breeding meerkat Suricata suricatta, group members emit soft contact calls, termed as ＂close calls＂, while foraging in order to maintain group cohesion. Here, we investigated how the close calling rate during foraging was affected by the presence of pups, that produce continuous, noisy begging calls as they follow older group members. Adults decreased their overall close call rate substantially when pups were foraging with the group in comparison to periods when no pups were present. We suggest this decrease was likely due to a masking effect of the loud begging calls, which makes the close call function of maintaining group cohesion partly redundant as the centrally located begging calls can be used in- stead to maintain cohesion. There was some support that adults use close calls strategically to at- tract specific pups based on fitness advantages, that is, as the philopatric sex, females should call more than males and more to female pups than male pups. Dominant females called more than dominant males when a pup was in close proximity, while subordinates showed no sex-based dif- ferences. The sex of the nearest pup did not affect the calling rate of adults. The study shows that meerkats modify their close call production depending on benefits gained from calling and provides an example of the flexible use of one calling system in the presence of another, here contact calls versus begging calls, within the same species.展开更多
Objective：To explore a surgical model of utilizing consecutive free scapular flap and adjacent pedicled flap transfer for repairing massive soft tissue defects on the dorsum of the hand while minimizing the donor sit...Objective：To explore a surgical model of utilizing consecutive free scapular flap and adjacent pedicled flap transfer for repairing massive soft tissue defects on the dorsum of the hand while minimizing the donor site morbidity.Methods：Six patients with massive soft tissue injuries on the opisthenar and forearm were treated with free scapular flaps.Afterwards,a pedicled flap adjacent to the donor site was transferred to cover the donor site defect by direct closure.Results：All six free scapular flaps survived without signs of infection.Three adjacent pedicled flaps presented minor signs of insufficient blood flow on the distal apex,which resolved after six weeks with only conservative therapy.All the incisions healed without other complications.At six-month follow-up,the patients regained full shoulder function.Conclusion：With the assistance of an adjacent pedicled flap,the scapular flap is a highly applicable approach in repairing massive soft tissue defects in the opisthenar.It can achieve positive outcomes in both reconstructive and aesthetic aspects.展开更多
The tracheocutaneous fistula after tracheostomy is a complex clinical problem. An ideal fistula closure is still difficult at present though a variety of fistula-closing methods have been reported in the literature. W...The tracheocutaneous fistula after tracheostomy is a complex clinical problem. An ideal fistula closure is still difficult at present though a variety of fistula-closing methods have been reported in the literature. We used a turnover skin flap to cover the fistula. All the procedures were completed at bedside under local anesthesia. The fistula was successfully closed and well healed without complications within 7-9 days. It has been proven that this operation is simple, effective, and safe.展开更多
基金Project(2019 YFB 2004700)supported by the National Key R&D Project of ChinaProject(HTL-O-19 K 02)supported by National Key Laboratory of Science and Technology on Helicopter Transmission,Nanjing University of Aeronautics and Astronautics,China。
文摘Worm grinding has been applied to manufacture gears to pursue high accuracy and fine surface finish.When the worm used to grind face gears is manufactured with multi-axis computer numerical control(CNC)machining,the machining accuracy is usually improved by increasing the number of tool paths with more time cost.Differently,this work proposes a generated method to improve the efficiency by dressing the worm surface with only one path,and a closed-loop manufacturing process is applied to ensure the machining accuracy.According to an advanced geometric analysis,the worm surface is practically approximated as a swept surface generated by a planar curve.Meanwhile,this curve is applied as the profile of a dressing wheel,which is used to dress the worm surface.The practical machining is carried out in a CNC machine tool,which was originally used to grind helical gears.Finally,a closed-loop manufacturing process including machining,measurement,and modification is proposed to compensate the machining errors.The proposed method is validated with simulations and practical experiments.
文摘In animals, signaling behavior is often context-dependent, with variation in the probability of emitting certain signals dependent on fitness advantages. Senders may adjust signaling rate depending on receiver identity, presence of audiences, or noise masking the signal, all of which can affect the benefits and costs of signal production. In the cooperative breeding meerkat Suricata suricatta, group members emit soft contact calls, termed as ＂close calls＂, while foraging in order to maintain group cohesion. Here, we investigated how the close calling rate during foraging was affected by the presence of pups, that produce continuous, noisy begging calls as they follow older group members. Adults decreased their overall close call rate substantially when pups were foraging with the group in comparison to periods when no pups were present. We suggest this decrease was likely due to a masking effect of the loud begging calls, which makes the close call function of maintaining group cohesion partly redundant as the centrally located begging calls can be used in- stead to maintain cohesion. There was some support that adults use close calls strategically to at- tract specific pups based on fitness advantages, that is, as the philopatric sex, females should call more than males and more to female pups than male pups. Dominant females called more than dominant males when a pup was in close proximity, while subordinates showed no sex-based dif- ferences. The sex of the nearest pup did not affect the calling rate of adults. The study shows that meerkats modify their close call production depending on benefits gained from calling and provides an example of the flexible use of one calling system in the presence of another, here contact calls versus begging calls, within the same species.
文摘Objective：To explore a surgical model of utilizing consecutive free scapular flap and adjacent pedicled flap transfer for repairing massive soft tissue defects on the dorsum of the hand while minimizing the donor site morbidity.Methods：Six patients with massive soft tissue injuries on the opisthenar and forearm were treated with free scapular flaps.Afterwards,a pedicled flap adjacent to the donor site was transferred to cover the donor site defect by direct closure.Results：All six free scapular flaps survived without signs of infection.Three adjacent pedicled flaps presented minor signs of insufficient blood flow on the distal apex,which resolved after six weeks with only conservative therapy.All the incisions healed without other complications.At six-month follow-up,the patients regained full shoulder function.Conclusion：With the assistance of an adjacent pedicled flap,the scapular flap is a highly applicable approach in repairing massive soft tissue defects in the opisthenar.It can achieve positive outcomes in both reconstructive and aesthetic aspects.
文摘The tracheocutaneous fistula after tracheostomy is a complex clinical problem. An ideal fistula closure is still difficult at present though a variety of fistula-closing methods have been reported in the literature. We used a turnover skin flap to cover the fistula. All the procedures were completed at bedside under local anesthesia. The fistula was successfully closed and well healed without complications within 7-9 days. It has been proven that this operation is simple, effective, and safe.
