On the basis of controlled Lagrangians,a controller design is proposed for underactuated mechanical systems with two degrees of freedom.A new kinetic energy equation(K-equation)independent of the gyroscopic forces is ...On the basis of controlled Lagrangians,a controller design is proposed for underactuated mechanical systems with two degrees of freedom.A new kinetic energy equation(K-equation)independent of the gyroscopic forces is found due to the use of their property.As a result,the necessary and sufficient matching condition comprises the new K-equation and the potential energy equation(P-equation)cascaded,the regular condition,and the explicit gyroscopic forces.Further,for two classes of input decoupled systems that cover the main benchmark examples,the new K-equation,respectively,degenerates from a quasilinear partial differential equation(PDE)into an ordinary differential equation(ODE)under some choice and into a homogeneous linear PDE with two kinds of explicit general solutions.Benefiting from one of the general solutions,the obtained smooth state feedback controller for the Acrobots is of a more general form.Specifically,a constant fixed in a related paper by the system parameters is converted into a controller parameter ranging over an open interval along with some new nonlinear terms involved.Unlike what is mentioned in the related paper,some categories of the Acrobots cannot be stabilized with the existing interconnection and damping assignment passivity based control(IDA-PBC)method.As a contribution,the system can be locally asymptotically stabilized by the selection of the new controller parameter except for only one special case.展开更多
Multiple hetero-interfaces would strengthen interfacial polarization and boost electromagnetic wave absorption,but still remain the formidable challenges in decreasing filler loadings.Herein,sandwich NC@Co/NC@MnO_(2)c...Multiple hetero-interfaces would strengthen interfacial polarization and boost electromagnetic wave absorption,but still remain the formidable challenges in decreasing filler loadings.Herein,sandwich NC@Co/NC@MnO_(2)composites with hollow cavity,multiple hetero-interfaces,and hierarchical structures have been fabricated via the cooperative processes of self-sacrifice strategy and sequential hydrothermal reaction.In the sandwich composites,middle magnetic components(Co/NC)are wrapped by inner N-doped carbon(NC)matrix and outer hierarchical MnO_(2)nanosheets.Importantly,hollow engineering of sandwich composites with multiple hetero-interfaces greatly facilitates the enhancement of absorption bandwidth without sacrificing the absorption intensity.The maximum reflection loss of sandwich NC@Co/NC@MnO_(2)composites reaches-44.8 dB at 2.5 mm and the effective bandwidths is achieved as wide as 9.6 GHz at 2.3 mm.These results provide us a new insight into preparing efficient electromagnetic wave absorbers by interface engineering and hollow construction.展开更多
OBJECTIVE： To investigate the traditional Chinese Medicine （TCM） etiology and pathogenesis of ac- quired immune deficiency syndrome （AIDS） by 18-month observation of Chinese rhesus macaques infected with simian i...OBJECTIVE： To investigate the traditional Chinese Medicine （TCM） etiology and pathogenesis of ac- quired immune deficiency syndrome （AIDS） by 18-month observation of Chinese rhesus macaques infected with simian immunodeficiency virus （SIV） mac239. METHODS： Thirty-five healthy Chinese rhesus ma- caques were divided into a model group （n=30） and a control group （n=5）. The model was estab- lished by inoculating monkeys intravenously with SIVmac239. Changes in TCM symptoms after SIV in- fection within 18 months were then observed and recorded. Routine blood tests, SIV viral load, T-lym-phocyte subsets, plasma triiodothyronine （T3）, tet- raiodothyronine （14）, adrenocorticotropic hormone （ACTH） and cortisol （Cor） were tested periodically during the experiment. RESULTS： During the acute infection period of SIV, model monkeys temporarily showed clinical symp- toms such as diarrhea, dysphoria and slight weight loss. Decrease percentages of CD4~ T-lymphocytes were observed but levels of T3, 14, Cot, and ACTH were relatively unchanged. Monkeys in the model group during the early and middle periods of infec- tion showed no obvious symptoms, except few monkeys exhibited transient diarrhea and reduced food intake. All variables at this stage showed nor- mal fluctuations. In the middle period model group monkeys showed chronic and persistent diarrhea, weight loss, reduced food intake and low levels of 13 and Cot. In the late period, symptoms including emaciation, weight loss, listlessness, crouching in corners and low levels of T3appeared. CONCLUSION： The results suggest that the rhesus monkey SIWSAIDS model can be applied to re- search on TCM etiology and pathogenesis of AIDS. According to this model, the etiology of disease is the SIV virus. The pathogenesis manifests as the in- vasion of SIV virus, incubation of the virus, balance between virus and healthy ＂Qi＂, damage to spleen and kidney as the disease progressed, exhaustion of vitality and finally the failure of five zang and six fu organs.展开更多
The robust guarantee of train control on-board equipment is inextricably linked to the safe functioning of a high-speed train.A fault diagnostic model of on-board equipment is built utilizing the integrated learning X...The robust guarantee of train control on-board equipment is inextricably linked to the safe functioning of a high-speed train.A fault diagnostic model of on-board equipment is built utilizing the integrated learning XGBoost(eXtreme Gradient Boosting)algorithm to help technicians assess the malfunction category of high-speed train control on-board equipment accurately and rapidly.The XGBoost algorithm iterates multiple decision tree models to improve the accuracy of fault diagnosis by lifting the predicted residual and adding regular terms.To begin,the text features were extracted using the improved TF-IDF(Term Frequency-Inverse Document Frequency)approach,and 24 fault feature words were chosen and converted into weight word vectors.Secondly,considering the imbalanced fault categories in the data set,the ADASYN(Adaptive Synthetic sampling)adaptive synthetically oversampling technique was used to synthesize a few category fault samples.Finally,the data samples were split into training and test sets based on the fault text data of CTCS-3train control on-board equipment recorded by Guangzhou Railway Group maintenance personnel.The XGBoost model was utilized to realize the automatic fault location of the test set after optimized parameter tuning through grid search.Compared with other methods,the evaluation index of the XGBoost model was significantly improved.The diagnostic accuracy reached 95.43%,which verifies the effectiveness of the method in text fault diagnosis.展开更多
文摘On the basis of controlled Lagrangians,a controller design is proposed for underactuated mechanical systems with two degrees of freedom.A new kinetic energy equation(K-equation)independent of the gyroscopic forces is found due to the use of their property.As a result,the necessary and sufficient matching condition comprises the new K-equation and the potential energy equation(P-equation)cascaded,the regular condition,and the explicit gyroscopic forces.Further,for two classes of input decoupled systems that cover the main benchmark examples,the new K-equation,respectively,degenerates from a quasilinear partial differential equation(PDE)into an ordinary differential equation(ODE)under some choice and into a homogeneous linear PDE with two kinds of explicit general solutions.Benefiting from one of the general solutions,the obtained smooth state feedback controller for the Acrobots is of a more general form.Specifically,a constant fixed in a related paper by the system parameters is converted into a controller parameter ranging over an open interval along with some new nonlinear terms involved.Unlike what is mentioned in the related paper,some categories of the Acrobots cannot be stabilized with the existing interconnection and damping assignment passivity based control(IDA-PBC)method.As a contribution,the system can be locally asymptotically stabilized by the selection of the new controller parameter except for only one special case.
基金support from the National Natural Science Foundation of China(No.U21A2093)Natural Science Foundation of Shaanxi Province(No.2022JM-260)Fundamental Research Funds for the Central Universities(No.G2022KY05109).This work is also financially supported by the Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars.We would like to thank Zhang San from Shiyanjia Lab(www.shiyanjia.com)for the VSM analysis.
文摘Multiple hetero-interfaces would strengthen interfacial polarization and boost electromagnetic wave absorption,but still remain the formidable challenges in decreasing filler loadings.Herein,sandwich NC@Co/NC@MnO_(2)composites with hollow cavity,multiple hetero-interfaces,and hierarchical structures have been fabricated via the cooperative processes of self-sacrifice strategy and sequential hydrothermal reaction.In the sandwich composites,middle magnetic components(Co/NC)are wrapped by inner N-doped carbon(NC)matrix and outer hierarchical MnO_(2)nanosheets.Importantly,hollow engineering of sandwich composites with multiple hetero-interfaces greatly facilitates the enhancement of absorption bandwidth without sacrificing the absorption intensity.The maximum reflection loss of sandwich NC@Co/NC@MnO_(2)composites reaches-44.8 dB at 2.5 mm and the effective bandwidths is achieved as wide as 9.6 GHz at 2.3 mm.These results provide us a new insight into preparing efficient electromagnetic wave absorbers by interface engineering and hollow construction.
基金Supported by the National Science and Technology Major Project "Optimization for prescription of anti-HIV Chinese medicine and the study on animal model for AIDS with TCM symptoms(No.2008ZX10005-005)National Key Discipline Construction funding for clinical basic of TCM in Guangzhou university of Chinese Medicine
文摘OBJECTIVE： To investigate the traditional Chinese Medicine （TCM） etiology and pathogenesis of ac- quired immune deficiency syndrome （AIDS） by 18-month observation of Chinese rhesus macaques infected with simian immunodeficiency virus （SIV） mac239. METHODS： Thirty-five healthy Chinese rhesus ma- caques were divided into a model group （n=30） and a control group （n=5）. The model was estab- lished by inoculating monkeys intravenously with SIVmac239. Changes in TCM symptoms after SIV in- fection within 18 months were then observed and recorded. Routine blood tests, SIV viral load, T-lym-phocyte subsets, plasma triiodothyronine （T3）, tet- raiodothyronine （14）, adrenocorticotropic hormone （ACTH） and cortisol （Cor） were tested periodically during the experiment. RESULTS： During the acute infection period of SIV, model monkeys temporarily showed clinical symp- toms such as diarrhea, dysphoria and slight weight loss. Decrease percentages of CD4~ T-lymphocytes were observed but levels of T3, 14, Cot, and ACTH were relatively unchanged. Monkeys in the model group during the early and middle periods of infec- tion showed no obvious symptoms, except few monkeys exhibited transient diarrhea and reduced food intake. All variables at this stage showed nor- mal fluctuations. In the middle period model group monkeys showed chronic and persistent diarrhea, weight loss, reduced food intake and low levels of 13 and Cot. In the late period, symptoms including emaciation, weight loss, listlessness, crouching in corners and low levels of T3appeared. CONCLUSION： The results suggest that the rhesus monkey SIWSAIDS model can be applied to re- search on TCM etiology and pathogenesis of AIDS. According to this model, the etiology of disease is the SIV virus. The pathogenesis manifests as the in- vasion of SIV virus, incubation of the virus, balance between virus and healthy ＂Qi＂, damage to spleen and kidney as the disease progressed, exhaustion of vitality and finally the failure of five zang and six fu organs.
基金supported by the Science and Tec hnology Research and Development Plan Contract of China National Railway Group Co.,Ltd(Grant No.N2022G012)the Railway Science and Technology Research and Development Center Project(Project No.SYF2022SJ004).
文摘The robust guarantee of train control on-board equipment is inextricably linked to the safe functioning of a high-speed train.A fault diagnostic model of on-board equipment is built utilizing the integrated learning XGBoost(eXtreme Gradient Boosting)algorithm to help technicians assess the malfunction category of high-speed train control on-board equipment accurately and rapidly.The XGBoost algorithm iterates multiple decision tree models to improve the accuracy of fault diagnosis by lifting the predicted residual and adding regular terms.To begin,the text features were extracted using the improved TF-IDF(Term Frequency-Inverse Document Frequency)approach,and 24 fault feature words were chosen and converted into weight word vectors.Secondly,considering the imbalanced fault categories in the data set,the ADASYN(Adaptive Synthetic sampling)adaptive synthetically oversampling technique was used to synthesize a few category fault samples.Finally,the data samples were split into training and test sets based on the fault text data of CTCS-3train control on-board equipment recorded by Guangzhou Railway Group maintenance personnel.The XGBoost model was utilized to realize the automatic fault location of the test set after optimized parameter tuning through grid search.Compared with other methods,the evaluation index of the XGBoost model was significantly improved.The diagnostic accuracy reached 95.43%,which verifies the effectiveness of the method in text fault diagnosis.
