Efficient monitoring of bone milling conditions in orthopedic and neurosurgical surgery can prevent tissue,bone,and tool damage,and reduce surgery time.Current researches are mainly focused on recognizing the cutting ...Efficient monitoring of bone milling conditions in orthopedic and neurosurgical surgery can prevent tissue,bone,and tool damage,and reduce surgery time.Current researches are mainly focused on recognizing the cutting state using force signal.However,the force signal during the milling process is difficult and expensive to acquire.In this study,a neural network-based method is proposed to recognize the cutting state and force during the bone milling process using sound signals.Numerical modeling of the cutting force is performed to capture the relationship between the cutting force and the depth of cut in the bone milling process.The force model is used to calibrate the training data to improve the recognition accuracy.Wavelet package transform is used for signal processing to understand bone-cutting phenomena using sound signals.The proposed system succeeds to monitor the bone milling process to reduce the surgical risk.Experiments on standard bone specimens and vertebrae also indicate that the proposed approach has considerable potential for use in computer-assisted and robot-assisted bone-cutting systems used in various types of surgery.展开更多
The static nonlinear magnetic response of randomly pinned flux-line lattice in a type-Ⅱ super-conductor has been investigated using variational replica-symmetry-broken method.A peak in the curve of susceptibility as ...The static nonlinear magnetic response of randomly pinned flux-line lattice in a type-Ⅱ super-conductor has been investigated using variational replica-symmetry-broken method.A peak in the curve of susceptibility as a function of external magnetic field is found.When the magnetic field is low,there is a softening in the susceptibility as an effect of pinning potential with nonzero correlation length.At some critical magnetic field,the softening changes into hardening.After reaching the maximum in hardening,the susceptibility decreases to its value of piire states with the increase of magnetic field.展开更多
In this study,a composite powder capillary wick is prepared,manufactured by sintering copper powder and surface treated by low-temperature thermal oxidation.It is used to improve the performance of the capillary wick....In this study,a composite powder capillary wick is prepared,manufactured by sintering copper powder and surface treated by low-temperature thermal oxidation.It is used to improve the performance of the capillary wick.The forced flow method and infrared imaging method are used to test the permeability and capillary performance of the samples.The effects of different oxidation temperatures on the performance of capillary wick are investigated.The experimental results show that the wetting performance of the oxidized samples is significantly enhanced.With the increase of oxidation temperature,the permeability decreases.The capillary height and velocity of the thermally oxidized samples are significantly higher than those of the untreated capillary wick.However,the oxidation temperature needs to be adjusted to obtain the best capillary performance.The highest capillary performance is found at oxidation temperature of 300℃,with an increase of 46% compared to the untreated ones.Comparisons with other composite wicks show that the sample with an oxidation temperature of 300℃ has competitive capillary performance,making it a favorable alternative to two-phase heat transfer device.This study shows that combining low-temperature thermal oxidation technology with powder sintering is a convenient and effective method to improve the capillary performance of powder wicks.展开更多
基金the Open Research Fund of State Key Laboratory of Digital Manufacturing Equipment and Technology,Huazhong University of Science and Technology(Grant No.DMETKF2020004).
文摘Efficient monitoring of bone milling conditions in orthopedic and neurosurgical surgery can prevent tissue,bone,and tool damage,and reduce surgery time.Current researches are mainly focused on recognizing the cutting state using force signal.However,the force signal during the milling process is difficult and expensive to acquire.In this study,a neural network-based method is proposed to recognize the cutting state and force during the bone milling process using sound signals.Numerical modeling of the cutting force is performed to capture the relationship between the cutting force and the depth of cut in the bone milling process.The force model is used to calibrate the training data to improve the recognition accuracy.Wavelet package transform is used for signal processing to understand bone-cutting phenomena using sound signals.The proposed system succeeds to monitor the bone milling process to reduce the surgical risk.Experiments on standard bone specimens and vertebrae also indicate that the proposed approach has considerable potential for use in computer-assisted and robot-assisted bone-cutting systems used in various types of surgery.
文摘The static nonlinear magnetic response of randomly pinned flux-line lattice in a type-Ⅱ super-conductor has been investigated using variational replica-symmetry-broken method.A peak in the curve of susceptibility as a function of external magnetic field is found.When the magnetic field is low,there is a softening in the susceptibility as an effect of pinning potential with nonzero correlation length.At some critical magnetic field,the softening changes into hardening.After reaching the maximum in hardening,the susceptibility decreases to its value of piire states with the increase of magnetic field.
基金financial support for this research from the National Natural Science Foundation of China (52006040 and 51876044)the Natural Science Foundation of Guangdong Province(2019B090905005)the International Science and Technology Projects of Huangpu District of Guangzhou City(2020GH08)。
文摘In this study,a composite powder capillary wick is prepared,manufactured by sintering copper powder and surface treated by low-temperature thermal oxidation.It is used to improve the performance of the capillary wick.The forced flow method and infrared imaging method are used to test the permeability and capillary performance of the samples.The effects of different oxidation temperatures on the performance of capillary wick are investigated.The experimental results show that the wetting performance of the oxidized samples is significantly enhanced.With the increase of oxidation temperature,the permeability decreases.The capillary height and velocity of the thermally oxidized samples are significantly higher than those of the untreated capillary wick.However,the oxidation temperature needs to be adjusted to obtain the best capillary performance.The highest capillary performance is found at oxidation temperature of 300℃,with an increase of 46% compared to the untreated ones.Comparisons with other composite wicks show that the sample with an oxidation temperature of 300℃ has competitive capillary performance,making it a favorable alternative to two-phase heat transfer device.This study shows that combining low-temperature thermal oxidation technology with powder sintering is a convenient and effective method to improve the capillary performance of powder wicks.
