An experimental system was established to explore the plasma flow control effect for helicopter rotors in hover mode.With the plasma actuator applied at the leading edge of the rotor blades,alternating current dielect...An experimental system was established to explore the plasma flow control effect for helicopter rotors in hover mode.With the plasma actuator applied at the leading edge of the rotor blades,alternating current dielectric barrier discharge(AC-DBD) plasma actuation was generated by a sinusoidal AC high-voltage generator.By direct force measurement,the influence of actuation parameters on the aerodynamic performance of the rotor was investigated at a tip Reynolds number of 1.7 × 105.AC-DBD actuation can delay the blade stall to more than 3° with a 20%increase of about in the thrust coefficient at the post-stall pitch.At a constant motor power driving the rotor,AC-DBD actuation could reduce the rotor’s torque at the stalled pitch and increase the rotational speed of the rotor.Also,AC-DBD actuation could maintain a relatively high hover efficiency of the rotor at large collective pitches.In a wide range of actuation parameters,AC-DBD plasma actuation could improve the rotor’s aerodynamic performance at large blade pitches.High-speed photography of the tuft motion on the blade’s upper surface showed that AC-DBD plasma actuation could promote the reattachment of the blade’s separation flow.展开更多
Magnesium(Mg) and its alloys have been intensively studied to develop the next generation of bone implants recently, but their clinical application is restricted by rapid degradation and unsatisfied osteogenic effect ...Magnesium(Mg) and its alloys have been intensively studied to develop the next generation of bone implants recently, but their clinical application is restricted by rapid degradation and unsatisfied osteogenic effect in vivo. A bioactive chemical conversion Mg-phenolic networks complex coating(e EGCG) was stepwise incorporated by epigallocatechin-3-gallate(EGCG) and exogenous Mg^(2+)on Mg-2Zn magnesium alloy. Simplex EGCG induced chemical conversion coating(c EGCG) was set as compare group. The in vitro corrosion behavior of Mg-2Zn alloy, c EGCG and e EGCG was evaluated in SBF using electrochemical(PDP, EIS) and immersion test. The cytocompatibility was investigated with rat bone marrow mesenchymal stem cells(r BMSCs). Furthermore, the in vivo tests using a rabbit model involved micro computed tomography(Micro-CT) analysis, histological observation, and interface analysis. The results showed that the e EGCG is Mgphenolic multilayer coating incorporated Mg-phenolic networks, which is rougher, more compact and much thicker than c EGCG. The e EGCG highly improved the corrosion resistance of Mg-2Zn alloy, combined with its lower average hemolytic ratios, continuous high scavenging effect ability and relatively moderate contact angle features, resulting in a stable and suitable biological environment, obviously promoted r BMSCs adhesion and proliferation. More importantly, Micro-CT, histological and interface elements distribution evaluations all revealed that the e EGCG effectively inhibited degradation and enhanced bone tissue formation of Mg alloy implants. This study puts forward a promising bioactive chemical conversion coating with Mg-phenolic networks for the application of biodegradable orthopedic implants.展开更多
Visual odometry is critical in visual simultaneous localization and mapping for robot navigation.However,the pose estimation performance of most current visual odometry algorithms degrades in scenes with unevenly dist...Visual odometry is critical in visual simultaneous localization and mapping for robot navigation.However,the pose estimation performance of most current visual odometry algorithms degrades in scenes with unevenly distributed features because dense features occupy excessive weight.Herein,a new human visual attention mechanism for point-and-line stereo visual odometry,which is called point-line-weight-mechanism visual odometry(PLWM-VO),is proposed to describe scene features in a global and balanced manner.A weight-adaptive model based on region partition and region growth is generated for the human visual attention mechanism,where sufficient attention is assigned to position-distinctive objects(sparse features in the environment).Furthermore,the sum of absolute differences algorithm is used to improve the accuracy of initialization for line features.Compared with the state-of-the-art method(ORB-VO),PLWM-VO show a 36.79%reduction in the absolute trajectory error on the Kitti and Euroc datasets.Although the time consumption of PLWM-VO is higher than that of ORB-VO,online test results indicate that PLWM-VO satisfies the real-time demand.The proposed algorithm not only significantly promotes the environmental adaptability of visual odometry,but also quantitatively demonstrates the superiority of the human visual attention mechanism.展开更多
BACKGROUND Hepatitis C infection not only damages the liver but also often accompanies many extrahepatic manifestations.Incidences of pulmonary hypertension(PH)caused by hepatitis C are rare,and incidences of concurre...BACKGROUND Hepatitis C infection not only damages the liver but also often accompanies many extrahepatic manifestations.Incidences of pulmonary hypertension(PH)caused by hepatitis C are rare,and incidences of concurrent nephrotic syndrome and polymyositis are even rarer.CASE SUMMARY Herein we describe the case of a 57-year-old woman who was admitted to our department for intermittent chest tightness upon exertion for 5 years,aggravated with dyspnea for 10 d.After relevant examinations she was diagnosed with PH,nephrotic syndrome,and polymyositis due to chronic hepatitis C infection.A multi-disciplinary recommendation was that the patient should be treated with sildenafil and macitentan in combination and methylprednisolone.During treatment autoimmune symptoms,liver function,hepatitis C RNA levels,and cardiac parameters of right heart catheterization were monitored closely.The patient showed significant improvement in 6-min walking distance from 100 to 300 m at 3-mo follow-up and pulmonary artery pressure drops to 50 mmHg.Long-term follow-up is needed to confirm further efficacy and safety.CONCLUSION Increasing evidence supports a relationship between hepatitis C infection and diverse extrahepatic manifestations,but it is very rare to have PH,nephrotic syndrome,and polymyositis in a single patient.We conducted a literature review on the management of several specific extrahepatic manifestations of hepatitis C.展开更多
The influence of acceleration of electrons on relativistic nonlinear Thomson scattering in tightly focused linearly polarized laser pulses is investigated for the first time. In the framework of classical electrodynam...The influence of acceleration of electrons on relativistic nonlinear Thomson scattering in tightly focused linearly polarized laser pulses is investigated for the first time. In the framework of classical electrodynamics, it is deduced and found that the more severe the change in the electron transverse acceleration, the stronger the asymmetry of the radiation angle distribution, and the greater the transverse acceleration, the greater the radiation energy. Tightly focused, ultrashort,and high-intensity lasers lead to violent electron acceleration processes, resulting in a bifurcated radiation structure with asymmetry and higher energy. Additionally, a change in the initial phase of the laser brings about periodic change of the acceleration, which in turn makes the radiation change periodically with the initial phase. In other cases, the radiation is in a symmetrical double-peak structure. These phenomena will help us to modulate radiation with more energy collimation.展开更多
In this paper, we mainly study the orbital graphs of primitive groups with the socle A<sub>7</sub> x A<sub>7 </sub>which acts by diagonal action. Firstly, we calculate the element conjugat...In this paper, we mainly study the orbital graphs of primitive groups with the socle A<sub>7</sub> x A<sub>7 </sub>which acts by diagonal action. Firstly, we calculate the element conjugate classes of A7</sub>, then we discuss the stabilizer of two points in A7</sub>. Finally, according to the relation between suborbit and orbital, we obtain the orbitals, and determine the orbital graphs.展开更多
It is essential to utilize deep-learning algorithms based on big data for the implementation of the new generation of artificial intelligence. Effective utilization of deep learning relies considerably on the number o...It is essential to utilize deep-learning algorithms based on big data for the implementation of the new generation of artificial intelligence. Effective utilization of deep learning relies considerably on the number of labeled samples, which restricts the application of deep learning in an environment with a small sample size. In this paper, we propose an approach based on a generative adversarial network (GAN) combined with a deep neural network (DNN). First, the original samples were divided into a training set and a test set. The GAN was trained with the training set to generate synthetic sample data, which enlarged the training set. Next, the DNN classifier was trained with the synthetic samples. Finally, the classifier was tested with the test set, and the effectiveness of the approach for multi-classification with a small sample size was validated by the indicators. As an empirical case, the approach was then applied to identify the stages of cancers with a small labeled sample size. The experimental results verified that the proposed approach achieved a greater accuracy than traditional methods. This research was an attempt to transform the classical statistical machine-learning classification method based on original samples into a deep-learning classification method based on data augmentation. The use of this approach will contribute to an expansion of application scenarios for the new generation of artificial intelligence based on deep learning, and to an increase in application effectiveness. This research is also expected to contribute to the comprehensive promotion of new-generation artificial intelligence.展开更多
The thermodynamic properties of metamizol monohydrate in pure solvents(methanol,ethanol,n-propanol and isopropanol) and two binary mixed solvent systems including(methanol+ethanol) and(methanol+isopropanol) were measu...The thermodynamic properties of metamizol monohydrate in pure solvents(methanol,ethanol,n-propanol and isopropanol) and two binary mixed solvent systems including(methanol+ethanol) and(methanol+isopropanol) were measured from 283.15 K to 313.15 K by gravimetric method under atmospheric pressure thought as 0.1 MPa.The modi fied Apelblat equation,the CNIBS/R-K equation,the Hybrid model and the NRTL model were used to correlate the solubility of metamizol monohydrate,respectively.The results show that the solubility of metamizol monohydrate in all the tested solvents increases with the rising temperature which means that it has temperature dependence.What's more,the effects of solvent components of the binary solvent mixtures on solubility were discussed,it illustrates that the increasing of the molar fraction of methanol gives the system a greater dissolving power.Furthermore,according to the NRTL model,the enthalpy,the Gibbs energy and the entropy of the mixing process were also obtained and discussed.展开更多
目的目前美军较为成熟的战伤编码系统为美军战地医疗系统伤情编码(Deployable medical systems patient conditions,PCs)和美军战伤定级编码系统(Military Combat Injury Scale,MCIS)。PCs由于包含战伤诊断、救治概要、生存概率以及后...目的目前美军较为成熟的战伤编码系统为美军战地医疗系统伤情编码(Deployable medical systems patient conditions,PCs)和美军战伤定级编码系统(Military Combat Injury Scale,MCIS)。PCs由于包含战伤诊断、救治概要、生存概率以及后送要求等要素,广泛应用于卫勤领域的模拟仿真系统,但对于真实战伤诊断数据的编码率较低,且无法对严重程度定级。MCIS具有针对强、简单易用等特点,能够较好地对真实战伤诊断进行编码并对战伤严重度定级,但目前仅包括战伤诊断要素,缺少卫勤决策支持的其他要素。因此本文通过对两套编码系统进行对比与转换研究,探究建立两套编码系统转换规则的可行性,从而使得真实战伤数据和模拟仿真数据相结合,共同为卫勤决策提供支持,并为构建我军战伤编码提供建议。方法提取PCs中187个战伤伤情编码,将PCs和MCIS编码指导手册分别交给3名资深编码员,分别将两套编码进行匹配并记录。计算不同编码员匹配记录的加权Kappa系数用以评价评分者间信度。结果两套编码匹配记录的评分者信度较差。结论亟待建立一套既能编码真实战伤诊断数据,又涵盖卫勤决策支持要素的战伤分类与编码系统,从而将真实数据与模拟仿真数据相结合,共同形成决策证据为卫勤保障提供决策支持。展开更多
基金funded by the National Key Research and Development Program of China(No.2021YFB3700801)by the State Key Laboratory of Powder Metallurgy,Central South University,Changsha,China。
文摘An experimental system was established to explore the plasma flow control effect for helicopter rotors in hover mode.With the plasma actuator applied at the leading edge of the rotor blades,alternating current dielectric barrier discharge(AC-DBD) plasma actuation was generated by a sinusoidal AC high-voltage generator.By direct force measurement,the influence of actuation parameters on the aerodynamic performance of the rotor was investigated at a tip Reynolds number of 1.7 × 105.AC-DBD actuation can delay the blade stall to more than 3° with a 20%increase of about in the thrust coefficient at the post-stall pitch.At a constant motor power driving the rotor,AC-DBD actuation could reduce the rotor’s torque at the stalled pitch and increase the rotational speed of the rotor.Also,AC-DBD actuation could maintain a relatively high hover efficiency of the rotor at large collective pitches.In a wide range of actuation parameters,AC-DBD plasma actuation could improve the rotor’s aerodynamic performance at large blade pitches.High-speed photography of the tuft motion on the blade’s upper surface showed that AC-DBD plasma actuation could promote the reattachment of the blade’s separation flow.
基金supported by the Key Research and Development Program of Shaanxi Province (2019ZDLSF03-06) and (2020ZDLGY13-05)the National Key Research and Development Program of China (2020YFC1107202)。
文摘Magnesium(Mg) and its alloys have been intensively studied to develop the next generation of bone implants recently, but their clinical application is restricted by rapid degradation and unsatisfied osteogenic effect in vivo. A bioactive chemical conversion Mg-phenolic networks complex coating(e EGCG) was stepwise incorporated by epigallocatechin-3-gallate(EGCG) and exogenous Mg^(2+)on Mg-2Zn magnesium alloy. Simplex EGCG induced chemical conversion coating(c EGCG) was set as compare group. The in vitro corrosion behavior of Mg-2Zn alloy, c EGCG and e EGCG was evaluated in SBF using electrochemical(PDP, EIS) and immersion test. The cytocompatibility was investigated with rat bone marrow mesenchymal stem cells(r BMSCs). Furthermore, the in vivo tests using a rabbit model involved micro computed tomography(Micro-CT) analysis, histological observation, and interface analysis. The results showed that the e EGCG is Mgphenolic multilayer coating incorporated Mg-phenolic networks, which is rougher, more compact and much thicker than c EGCG. The e EGCG highly improved the corrosion resistance of Mg-2Zn alloy, combined with its lower average hemolytic ratios, continuous high scavenging effect ability and relatively moderate contact angle features, resulting in a stable and suitable biological environment, obviously promoted r BMSCs adhesion and proliferation. More importantly, Micro-CT, histological and interface elements distribution evaluations all revealed that the e EGCG effectively inhibited degradation and enhanced bone tissue formation of Mg alloy implants. This study puts forward a promising bioactive chemical conversion coating with Mg-phenolic networks for the application of biodegradable orthopedic implants.
基金Supported by Tianjin Municipal Natural Science Foundation of China(Grant No.19JCJQJC61600)Hebei Provincial Natural Science Foundation of China(Grant Nos.F2020202051,F2020202053).
文摘Visual odometry is critical in visual simultaneous localization and mapping for robot navigation.However,the pose estimation performance of most current visual odometry algorithms degrades in scenes with unevenly distributed features because dense features occupy excessive weight.Herein,a new human visual attention mechanism for point-and-line stereo visual odometry,which is called point-line-weight-mechanism visual odometry(PLWM-VO),is proposed to describe scene features in a global and balanced manner.A weight-adaptive model based on region partition and region growth is generated for the human visual attention mechanism,where sufficient attention is assigned to position-distinctive objects(sparse features in the environment).Furthermore,the sum of absolute differences algorithm is used to improve the accuracy of initialization for line features.Compared with the state-of-the-art method(ORB-VO),PLWM-VO show a 36.79%reduction in the absolute trajectory error on the Kitti and Euroc datasets.Although the time consumption of PLWM-VO is higher than that of ORB-VO,online test results indicate that PLWM-VO satisfies the real-time demand.The proposed algorithm not only significantly promotes the environmental adaptability of visual odometry,but also quantitatively demonstrates the superiority of the human visual attention mechanism.
文摘BACKGROUND Hepatitis C infection not only damages the liver but also often accompanies many extrahepatic manifestations.Incidences of pulmonary hypertension(PH)caused by hepatitis C are rare,and incidences of concurrent nephrotic syndrome and polymyositis are even rarer.CASE SUMMARY Herein we describe the case of a 57-year-old woman who was admitted to our department for intermittent chest tightness upon exertion for 5 years,aggravated with dyspnea for 10 d.After relevant examinations she was diagnosed with PH,nephrotic syndrome,and polymyositis due to chronic hepatitis C infection.A multi-disciplinary recommendation was that the patient should be treated with sildenafil and macitentan in combination and methylprednisolone.During treatment autoimmune symptoms,liver function,hepatitis C RNA levels,and cardiac parameters of right heart catheterization were monitored closely.The patient showed significant improvement in 6-min walking distance from 100 to 300 m at 3-mo follow-up and pulmonary artery pressure drops to 50 mmHg.Long-term follow-up is needed to confirm further efficacy and safety.CONCLUSION Increasing evidence supports a relationship between hepatitis C infection and diverse extrahepatic manifestations,but it is very rare to have PH,nephrotic syndrome,and polymyositis in a single patient.We conducted a literature review on the management of several specific extrahepatic manifestations of hepatitis C.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10947170/A05 and 11104291)Natural Science Fund for Colleges and Universities in Jiangsu Province(Grant No.10KJB140006)+2 种基金Natural Sciences Foundation of Shanghai(Grant No.11ZR1441300)Natural Science Foundation of Nanjing University of Posts and Telecommunications(Grant No.NY221098)sponsored by the Jiangsu Qing Lan Project and STITP Project(Grant No.XYB2013012)。
文摘The influence of acceleration of electrons on relativistic nonlinear Thomson scattering in tightly focused linearly polarized laser pulses is investigated for the first time. In the framework of classical electrodynamics, it is deduced and found that the more severe the change in the electron transverse acceleration, the stronger the asymmetry of the radiation angle distribution, and the greater the transverse acceleration, the greater the radiation energy. Tightly focused, ultrashort,and high-intensity lasers lead to violent electron acceleration processes, resulting in a bifurcated radiation structure with asymmetry and higher energy. Additionally, a change in the initial phase of the laser brings about periodic change of the acceleration, which in turn makes the radiation change periodically with the initial phase. In other cases, the radiation is in a symmetrical double-peak structure. These phenomena will help us to modulate radiation with more energy collimation.
文摘In this paper, we mainly study the orbital graphs of primitive groups with the socle A<sub>7</sub> x A<sub>7 </sub>which acts by diagonal action. Firstly, we calculate the element conjugate classes of A7</sub>, then we discuss the stabilizer of two points in A7</sub>. Finally, according to the relation between suborbit and orbital, we obtain the orbitals, and determine the orbital graphs.
基金the National Natural Science Foundation of China (91646102, L1724034, L16240452, L1524015, and 20905027)the MOE (Ministry of Education in China) Project of Humanities and Social Sciences (16JDGC011)+3 种基金the Chinese Academy of Engineering’s China Knowledge Center for Engineering Sciences and Technology Project (CKCEST-2018-1-13)the UK– China Industry Academia Partnership Programme (UK-CIAPP/260)Volvo-Supported Green Economy and Sustainable Development at Tsinghua University (20153000181)the Tsinghua Initiative Research Project (2016THZW).
文摘It is essential to utilize deep-learning algorithms based on big data for the implementation of the new generation of artificial intelligence. Effective utilization of deep learning relies considerably on the number of labeled samples, which restricts the application of deep learning in an environment with a small sample size. In this paper, we propose an approach based on a generative adversarial network (GAN) combined with a deep neural network (DNN). First, the original samples were divided into a training set and a test set. The GAN was trained with the training set to generate synthetic sample data, which enlarged the training set. Next, the DNN classifier was trained with the synthetic samples. Finally, the classifier was tested with the test set, and the effectiveness of the approach for multi-classification with a small sample size was validated by the indicators. As an empirical case, the approach was then applied to identify the stages of cancers with a small labeled sample size. The experimental results verified that the proposed approach achieved a greater accuracy than traditional methods. This research was an attempt to transform the classical statistical machine-learning classification method based on original samples into a deep-learning classification method based on data augmentation. The use of this approach will contribute to an expansion of application scenarios for the new generation of artificial intelligence based on deep learning, and to an increase in application effectiveness. This research is also expected to contribute to the comprehensive promotion of new-generation artificial intelligence.
基金Supported by National Natural Science Foundation of China(21206109)China Ministry of Science and Major National Scientific Instrument Development Project(21527812)
文摘The thermodynamic properties of metamizol monohydrate in pure solvents(methanol,ethanol,n-propanol and isopropanol) and two binary mixed solvent systems including(methanol+ethanol) and(methanol+isopropanol) were measured from 283.15 K to 313.15 K by gravimetric method under atmospheric pressure thought as 0.1 MPa.The modi fied Apelblat equation,the CNIBS/R-K equation,the Hybrid model and the NRTL model were used to correlate the solubility of metamizol monohydrate,respectively.The results show that the solubility of metamizol monohydrate in all the tested solvents increases with the rising temperature which means that it has temperature dependence.What's more,the effects of solvent components of the binary solvent mixtures on solubility were discussed,it illustrates that the increasing of the molar fraction of methanol gives the system a greater dissolving power.Furthermore,according to the NRTL model,the enthalpy,the Gibbs energy and the entropy of the mixing process were also obtained and discussed.
文摘目的目前美军较为成熟的战伤编码系统为美军战地医疗系统伤情编码(Deployable medical systems patient conditions,PCs)和美军战伤定级编码系统(Military Combat Injury Scale,MCIS)。PCs由于包含战伤诊断、救治概要、生存概率以及后送要求等要素,广泛应用于卫勤领域的模拟仿真系统,但对于真实战伤诊断数据的编码率较低,且无法对严重程度定级。MCIS具有针对强、简单易用等特点,能够较好地对真实战伤诊断进行编码并对战伤严重度定级,但目前仅包括战伤诊断要素,缺少卫勤决策支持的其他要素。因此本文通过对两套编码系统进行对比与转换研究,探究建立两套编码系统转换规则的可行性,从而使得真实战伤数据和模拟仿真数据相结合,共同为卫勤决策提供支持,并为构建我军战伤编码提供建议。方法提取PCs中187个战伤伤情编码,将PCs和MCIS编码指导手册分别交给3名资深编码员,分别将两套编码进行匹配并记录。计算不同编码员匹配记录的加权Kappa系数用以评价评分者间信度。结果两套编码匹配记录的评分者信度较差。结论亟待建立一套既能编码真实战伤诊断数据,又涵盖卫勤决策支持要素的战伤分类与编码系统,从而将真实数据与模拟仿真数据相结合,共同形成决策证据为卫勤保障提供决策支持。
