BACKGROUND Hoffa fracture is rare,especially in adolescents,and has a high rate of complications such as avascular necrosis and osteoarthritis;moreover,there are no definitive guidelines for its treatment.This report ...BACKGROUND Hoffa fracture is rare,especially in adolescents,and has a high rate of complications such as avascular necrosis and osteoarthritis;moreover,there are no definitive guidelines for its treatment.This report could provide a new potential treatment for Hoffa fracture.CASE SUMMARY A 16-year-old girl presented to the orthopedic emergency department of No.2 People’s Hospital of Yibin City with persistent pain following a right knee injury sustained during a sprint race.Her knee was swollen and tender,and the range of motion was restricted by the pain.X-ray and computed tomography revealed a Hoffa fracture in the right knee.After consultation,surgical treatment was performed,and the fracture was fixed with three 3.5-mm cannulated cancellous screws;osteochondral plugs that were harvested from the screw insertion site were re-implanted to cover the screw head.The patient’s fracture and osteochondral plug healed 6 mo postoperatively,and she presented a knee range of motion of 0–135 without pain,and was walking without support with a normal gait.CONCLUSION Here,we describe an innovative surgical procedure for Hoffa fracture that could provide a new possibility for the treatment of similar fractures,and further improve their management.展开更多
We propose a novel scheme of simultaneous polarization separation and switching, based on the orthogonallypolarized four-wave mixing(FWM) effect, for ultra-high-speed polarization multiplexing(Pol-MUX) fiber networks ...We propose a novel scheme of simultaneous polarization separation and switching, based on the orthogonallypolarized four-wave mixing(FWM) effect, for ultra-high-speed polarization multiplexing(Pol-MUX) fiber networks such as 100-Gbps and 400-Gbps backbone networks. We use theoretical and experimental analysis of the vector theory of FWM to successfully achieve polarization separation and all-optical switching by utilizing a 100-Gbps dual polarizationquadrature phase shift keying(DP-QPSK) signal and two orthogonally-polarized pumps. Both of the polarization-separated QPSK signals have clear constellation diagrams, with root mean square(RMS) error vector magnitudes(EVMs) of 14.32%and 14.11% respectively. The wavelengths of idlers can be created at 30 different wavelengths, which are consistent with International Telecommunication Union-Telecommunication(ITU-T) wavelengths, by flexibly changing the wavelength of the pump light. Moreover, the idlers that have distinct wavelengths have power distributed in a range from-10 dBm to-15 dBm, which can support error-free transmission. The power penaltyis 5 d B lower than that of back-to-back(BTB)signal for both the X-and Y-polarization components measured at a bit error ratio(BER) of 3.8×10^(-3). Our experimental results indicate that this scheme has promising applications in future backbone networks.展开更多
Perovskite/silicon(Si) tandem solar cells have been recognized as the next-generation photovoltaic technology with efficiency over 30% and low cost. However, the intrinsic instability of traditional three-dimensional(...Perovskite/silicon(Si) tandem solar cells have been recognized as the next-generation photovoltaic technology with efficiency over 30% and low cost. However, the intrinsic instability of traditional three-dimensional(3D) hybrid perovskite seriously hinders the lifetimes of tandem devices. In this work, the quasi-two-dimensional(2D)(BA)_(2)(MA)_(n-1)Pbn I_(3n+1)(n = 1, 2, 3, 4, 5)(where MA denotes methylammonium and BA represents butylammonium), with senior stability and wider bandgap, are first used as an absorber of semitransparent top perovskite solar cells(PSCs) to construct a fourterminal(4T) tandem devices with a bottom Si-heterojunction cell. The device model is established by Silvaco Atlas based on experimental parameters. Simulation results show that in the optimized tandem device, the top cell(n = 4) obtains a power conversion efficiency(PCE) of 17.39% and the Si bottom cell shows a PCE of 11.44%, thus an overall PCE of 28.83%. Furthermore, by introducing a 90-nm lithium fluoride(LiF) anti-reflection layer to reduce the surface reflection loss, the current density(J_(sc)) of the top cell is enhanced from 15.56 m A/cm^(2) to 17.09 m A/cm^(2), the corresponding PCE reaches 19.05%, and the tandem PCE increases to 30.58%. Simultaneously, in the cases of n = 3, 4, and 5, all the tandem PCEs exceed the limiting theoretical efficiency of Si cells. Therefore, the 4T quasi-2D perovskite/Si devices provide a more cost-effective tandem strategy and long-term stability solutions.展开更多
文摘BACKGROUND Hoffa fracture is rare,especially in adolescents,and has a high rate of complications such as avascular necrosis and osteoarthritis;moreover,there are no definitive guidelines for its treatment.This report could provide a new potential treatment for Hoffa fracture.CASE SUMMARY A 16-year-old girl presented to the orthopedic emergency department of No.2 People’s Hospital of Yibin City with persistent pain following a right knee injury sustained during a sprint race.Her knee was swollen and tender,and the range of motion was restricted by the pain.X-ray and computed tomography revealed a Hoffa fracture in the right knee.After consultation,surgical treatment was performed,and the fracture was fixed with three 3.5-mm cannulated cancellous screws;osteochondral plugs that were harvested from the screw insertion site were re-implanted to cover the screw head.The patient’s fracture and osteochondral plug healed 6 mo postoperatively,and she presented a knee range of motion of 0–135 without pain,and was walking without support with a normal gait.CONCLUSION Here,we describe an innovative surgical procedure for Hoffa fracture that could provide a new possibility for the treatment of similar fractures,and further improve their management.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFC0803900)the National Natural Science Foundation of China(Grant No.9163801)
文摘We propose a novel scheme of simultaneous polarization separation and switching, based on the orthogonallypolarized four-wave mixing(FWM) effect, for ultra-high-speed polarization multiplexing(Pol-MUX) fiber networks such as 100-Gbps and 400-Gbps backbone networks. We use theoretical and experimental analysis of the vector theory of FWM to successfully achieve polarization separation and all-optical switching by utilizing a 100-Gbps dual polarizationquadrature phase shift keying(DP-QPSK) signal and two orthogonally-polarized pumps. Both of the polarization-separated QPSK signals have clear constellation diagrams, with root mean square(RMS) error vector magnitudes(EVMs) of 14.32%and 14.11% respectively. The wavelengths of idlers can be created at 30 different wavelengths, which are consistent with International Telecommunication Union-Telecommunication(ITU-T) wavelengths, by flexibly changing the wavelength of the pump light. Moreover, the idlers that have distinct wavelengths have power distributed in a range from-10 dBm to-15 dBm, which can support error-free transmission. The power penaltyis 5 d B lower than that of back-to-back(BTB)signal for both the X-and Y-polarization components measured at a bit error ratio(BER) of 3.8×10^(-3). Our experimental results indicate that this scheme has promising applications in future backbone networks.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 62004151, 62274126, 62274126, 61874083, and 61804113)the China Postdoctoral Science Foundation (Grant No. 2020T130490)。
文摘Perovskite/silicon(Si) tandem solar cells have been recognized as the next-generation photovoltaic technology with efficiency over 30% and low cost. However, the intrinsic instability of traditional three-dimensional(3D) hybrid perovskite seriously hinders the lifetimes of tandem devices. In this work, the quasi-two-dimensional(2D)(BA)_(2)(MA)_(n-1)Pbn I_(3n+1)(n = 1, 2, 3, 4, 5)(where MA denotes methylammonium and BA represents butylammonium), with senior stability and wider bandgap, are first used as an absorber of semitransparent top perovskite solar cells(PSCs) to construct a fourterminal(4T) tandem devices with a bottom Si-heterojunction cell. The device model is established by Silvaco Atlas based on experimental parameters. Simulation results show that in the optimized tandem device, the top cell(n = 4) obtains a power conversion efficiency(PCE) of 17.39% and the Si bottom cell shows a PCE of 11.44%, thus an overall PCE of 28.83%. Furthermore, by introducing a 90-nm lithium fluoride(LiF) anti-reflection layer to reduce the surface reflection loss, the current density(J_(sc)) of the top cell is enhanced from 15.56 m A/cm^(2) to 17.09 m A/cm^(2), the corresponding PCE reaches 19.05%, and the tandem PCE increases to 30.58%. Simultaneously, in the cases of n = 3, 4, and 5, all the tandem PCEs exceed the limiting theoretical efficiency of Si cells. Therefore, the 4T quasi-2D perovskite/Si devices provide a more cost-effective tandem strategy and long-term stability solutions.