This paper presents a design method to implement an antenna array characterized by ultra-wide beam coverage,low profile,and low Sidelobe Level(SLL)for the application of Unmanned Aerial Vehicle(UAV)air-to-ground commu...This paper presents a design method to implement an antenna array characterized by ultra-wide beam coverage,low profile,and low Sidelobe Level(SLL)for the application of Unmanned Aerial Vehicle(UAV)air-to-ground communication.The array consists of ten broadside-radiating,ultrawide-beamwidth elements that are cascaded by a central-symmetry series-fed network with tapered currents following Dolph-Chebyshev distribution to provide low SLL.First,an innovative design of end-fire Huygens source antenna that is compatible with metal ground is presented.A low-profile,half-mode Microstrip Patch Antenna(MPA)is utilized to serve as the magnetic dipole and a monopole is utilized to serves as the electric dipole,constructing the compact,end-fire,grounded Huygens source antenna.Then,two opposite-oriented end-fire Huygens source antennas are seamlessly integrated into a single antenna element in the form of monopole-loaded MPA to accomplish the ultrawide,broadside-radiating beam.Particular consideration has been applied into the design of series-fed network as well as antenna element to compensate the adverse coupling effects between elements on the radiation performance.Experiment indicates an ultrawide Half-Power Beamwidth(HPBW)of 161°and a low SLL of-25 dB with a high gain of 12 d Bi under a single-layer configuration.The concurrent ultrawide beamwidth and low SLL make it particularly attractive for applications of UAV air-to-ground communication.展开更多
Anisotropic polyaniline （PAni） plates decorated with self-aligned nanofiber arrays were synthesized under the hydrothermaI conditions. The formation mechanism of the self-assembled structures was investigated by stu...Anisotropic polyaniline （PAni） plates decorated with self-aligned nanofiber arrays were synthesized under the hydrothermaI conditions. The formation mechanism of the self-assembled structures was investigated by studying the effect on PAni micro-structure with additive electrolyte in reaction system, and numerical simulation for dependence of systematic electrostatic energy on cross angles of self-assembled nanofiber arrays in grid textured PAni plates. It is proposed that the electrostatic interaction based on ionic doping charges plays an important role in the formation of the self-assembled PAni structures.展开更多
A highly efficient coupling reaction of N-heterocyclic carbene precursors with sulfonyl azides has been developed, affording a variety of pyrido[1,2-c][1,2,4]triazole-based π-conjugated triazenes. The present reactio...A highly efficient coupling reaction of N-heterocyclic carbene precursors with sulfonyl azides has been developed, affording a variety of pyrido[1,2-c][1,2,4]triazole-based π-conjugated triazenes. The present reaction proceeds under very mild conditions with good functional group tolerance. The resulting triazenes exhibit selective and sensitive fluorescent response toward Fe3+ion.展开更多
以国内2001—2022年中国知网(China National Knowledge Infrastructure,CNKI)数据库中有关教师反馈研究的700篇中文期刊文献为数据来源,借助可视化软件CiteSpace5.8.R3绘制科学知识图谱,分别对研究趋势、研究热点和研究进程进行探析。...以国内2001—2022年中国知网(China National Knowledge Infrastructure,CNKI)数据库中有关教师反馈研究的700篇中文期刊文献为数据来源,借助可视化软件CiteSpace5.8.R3绘制科学知识图谱,分别对研究趋势、研究热点和研究进程进行探析。结果表明:国内教师反馈研究于21年间呈波动上升态势;研究热点始终围绕“教师反馈”这一中心主题展开;研究领域在不同时期有各自的侧重点。希望分析结果能为今后国内教师反馈的深入研究提供借鉴。展开更多
BACKGROUND The Fontan operation is the only treatment option to change the anatomy of the heart and help improve patients’ hemodynamics.After successful operation,patients typically recover the ability to engage in g...BACKGROUND The Fontan operation is the only treatment option to change the anatomy of the heart and help improve patients’ hemodynamics.After successful operation,patients typically recover the ability to engage in general physical activity.As a better ventilatory strategy,extracorporeal membrane oxygenation(ECMO) provides gas exchange via an extracorporeal circuit,and is increasingly being used to improve respiratory and circulatory function.After the modified Fontan operation,circulation is different from that of patients who are not subjected to the procedure.This paper describe a successful case using ECMO in curing influenza A infection in a young man,who was diagnosed with Tausing-Bing syndrome and underwent Fontan operation 13 years ago.The special cardiac structure and circulatory characteristics are explored in this case.CASE SUMMARY We report a successful case using ECMO in curing influenza A infection in a 23-year-old man,who was diagnosed with Tausing-Bing syndrome and underwent Fontan operation 13 years ago.The man was admitted to the intensive care unit with severe acute respiratory distress syndrome as a result of influenza A infection.He was initially treated by veno-venous(VV) ECMO,which was switched to veno-venous-arterial ECMO(VVA ECMO) 5 d later.As circulation and respiratory function gradually improved,the VVA ECMO equipment was removed on May 1,2018.The patient was successfully withdrawn from artificial ventilation on May 28,2018 and then discharged from hospital on May 30,2018.CONCLUSION After the modified Fontan operation,circulation is different compared with that of patients who are not subjected to the procedure.There are certainly many differences between them when they receive the treatment of ECMO.Due to the special cardiac structure and circulatory characteristics,an individualized liquid management strategy is necessary and it might be better for them to choose an active circulation support earlier.展开更多
Background:Accurately diferentiating pneumocystis from cytomegalovirus pneumonia is crucial for correct therapy selection in AIDS patients.Hence,the goal of this study was to compare the computerized tomography(CT)fea...Background:Accurately diferentiating pneumocystis from cytomegalovirus pneumonia is crucial for correct therapy selection in AIDS patients.Hence,the goal of this study was to compare the computerized tomography(CT)features of pneumocystis pneumonia and cytomegalovirus pneumonia in AIDS patients and identify clinical hallmarks to accurately distinguish these two pathologies.Methods:A total of 112 AIDS patients(78 with pneumocystis pneumonia and 34 cytomegalovirus pneumonia)at Beijing Ditan Hospital from January 2017 to May 2019 were included in this study.Two experienced chest radiologists retrospectively reviewed CT images for 17 features including ground-glass opacity,consolidation,nodules,and halo sign.Binary logistic regression analyses were conducted to identify the signifcant parameters that distinguished pneumocystis pneumonia from cytomegalovirus pneumonia.Correlations were analyzed by Pearson or Spearman correlation analyses.Result were considered signifcant if P<0.05.Results:The presence of consolidation,halo signs,and nodules(all P<0.05)were signifcantly more frequent in patients with cytomegalovirus pneumonia than in those with pneumocystis pneumonia.Small nodules(32.5%in cytomegalovirus pneumonia,6.41%in pneumocystis pneumonia,P<0.001)without perilymphatic distribution were particularly common in patients with cytomegalovirus pneumonia.Large nodules were not found in any of patients with cytomegalovirus pneumonia.The presence of ground-glass opacity,reticulation,and bronchial wall thickening(all P>0.05)were common in both groups.Conclusions:Analysis of consolidation,nodules,and halo signs may contribute to the diferential diagnosis of pneumocystis pneumonia or cytomegalovirus pneumonia.However,some CT features considered typical in one or other diseases appear with similar frequency in both cohorts of AIDS patients.CT features are potentially useful for the diferential diagnosis of pneumocystis pneumonia and cytomegalovirus pneumonia in AIDS patients.展开更多
基金supported by the National Natural Science Foundation of China(No.62371080 and 62031006)the National Science Foundation of Chongqing,China(No.CSTB2022NSCQ-MSX0597)the Venture&Innovation Support Program for Chongqing Overseas Returnees,China(No.cx2022063)。
文摘This paper presents a design method to implement an antenna array characterized by ultra-wide beam coverage,low profile,and low Sidelobe Level(SLL)for the application of Unmanned Aerial Vehicle(UAV)air-to-ground communication.The array consists of ten broadside-radiating,ultrawide-beamwidth elements that are cascaded by a central-symmetry series-fed network with tapered currents following Dolph-Chebyshev distribution to provide low SLL.First,an innovative design of end-fire Huygens source antenna that is compatible with metal ground is presented.A low-profile,half-mode Microstrip Patch Antenna(MPA)is utilized to serve as the magnetic dipole and a monopole is utilized to serves as the electric dipole,constructing the compact,end-fire,grounded Huygens source antenna.Then,two opposite-oriented end-fire Huygens source antennas are seamlessly integrated into a single antenna element in the form of monopole-loaded MPA to accomplish the ultrawide,broadside-radiating beam.Particular consideration has been applied into the design of series-fed network as well as antenna element to compensate the adverse coupling effects between elements on the radiation performance.Experiment indicates an ultrawide Half-Power Beamwidth(HPBW)of 161°and a low SLL of-25 dB with a high gain of 12 d Bi under a single-layer configuration.The concurrent ultrawide beamwidth and low SLL make it particularly attractive for applications of UAV air-to-ground communication.
基金This work was supported by the National Natural Science Foundation of China （No.90606021, No.60676006, and No.60706019） and the State Key Program for Basic Research of China （No.2006CBOL1000）.
文摘Anisotropic polyaniline （PAni） plates decorated with self-aligned nanofiber arrays were synthesized under the hydrothermaI conditions. The formation mechanism of the self-assembled structures was investigated by studying the effect on PAni micro-structure with additive electrolyte in reaction system, and numerical simulation for dependence of systematic electrostatic energy on cross angles of self-assembled nanofiber arrays in grid textured PAni plates. It is proposed that the electrostatic interaction based on ionic doping charges plays an important role in the formation of the self-assembled PAni structures.
基金supported by the National Natural Science Foundation of China(No.21302081)the Scientific Fund of Sichuan Province,China(No.2014JQ0052)
文摘A highly efficient coupling reaction of N-heterocyclic carbene precursors with sulfonyl azides has been developed, affording a variety of pyrido[1,2-c][1,2,4]triazole-based π-conjugated triazenes. The present reaction proceeds under very mild conditions with good functional group tolerance. The resulting triazenes exhibit selective and sensitive fluorescent response toward Fe3+ion.
文摘以国内2001—2022年中国知网(China National Knowledge Infrastructure,CNKI)数据库中有关教师反馈研究的700篇中文期刊文献为数据来源,借助可视化软件CiteSpace5.8.R3绘制科学知识图谱,分别对研究趋势、研究热点和研究进程进行探析。结果表明:国内教师反馈研究于21年间呈波动上升态势;研究热点始终围绕“教师反馈”这一中心主题展开;研究领域在不同时期有各自的侧重点。希望分析结果能为今后国内教师反馈的深入研究提供借鉴。
基金Supported by the Capital Foundation of Medical Development,No. 2018-1-2171the Seedling Plan from the Beijing Ditan Hospital,Capital Medical University,No. DTYM201802。
文摘BACKGROUND The Fontan operation is the only treatment option to change the anatomy of the heart and help improve patients’ hemodynamics.After successful operation,patients typically recover the ability to engage in general physical activity.As a better ventilatory strategy,extracorporeal membrane oxygenation(ECMO) provides gas exchange via an extracorporeal circuit,and is increasingly being used to improve respiratory and circulatory function.After the modified Fontan operation,circulation is different from that of patients who are not subjected to the procedure.This paper describe a successful case using ECMO in curing influenza A infection in a young man,who was diagnosed with Tausing-Bing syndrome and underwent Fontan operation 13 years ago.The special cardiac structure and circulatory characteristics are explored in this case.CASE SUMMARY We report a successful case using ECMO in curing influenza A infection in a 23-year-old man,who was diagnosed with Tausing-Bing syndrome and underwent Fontan operation 13 years ago.The man was admitted to the intensive care unit with severe acute respiratory distress syndrome as a result of influenza A infection.He was initially treated by veno-venous(VV) ECMO,which was switched to veno-venous-arterial ECMO(VVA ECMO) 5 d later.As circulation and respiratory function gradually improved,the VVA ECMO equipment was removed on May 1,2018.The patient was successfully withdrawn from artificial ventilation on May 28,2018 and then discharged from hospital on May 30,2018.CONCLUSION After the modified Fontan operation,circulation is different compared with that of patients who are not subjected to the procedure.There are certainly many differences between them when they receive the treatment of ECMO.Due to the special cardiac structure and circulatory characteristics,an individualized liquid management strategy is necessary and it might be better for them to choose an active circulation support earlier.
文摘Background:Accurately diferentiating pneumocystis from cytomegalovirus pneumonia is crucial for correct therapy selection in AIDS patients.Hence,the goal of this study was to compare the computerized tomography(CT)features of pneumocystis pneumonia and cytomegalovirus pneumonia in AIDS patients and identify clinical hallmarks to accurately distinguish these two pathologies.Methods:A total of 112 AIDS patients(78 with pneumocystis pneumonia and 34 cytomegalovirus pneumonia)at Beijing Ditan Hospital from January 2017 to May 2019 were included in this study.Two experienced chest radiologists retrospectively reviewed CT images for 17 features including ground-glass opacity,consolidation,nodules,and halo sign.Binary logistic regression analyses were conducted to identify the signifcant parameters that distinguished pneumocystis pneumonia from cytomegalovirus pneumonia.Correlations were analyzed by Pearson or Spearman correlation analyses.Result were considered signifcant if P<0.05.Results:The presence of consolidation,halo signs,and nodules(all P<0.05)were signifcantly more frequent in patients with cytomegalovirus pneumonia than in those with pneumocystis pneumonia.Small nodules(32.5%in cytomegalovirus pneumonia,6.41%in pneumocystis pneumonia,P<0.001)without perilymphatic distribution were particularly common in patients with cytomegalovirus pneumonia.Large nodules were not found in any of patients with cytomegalovirus pneumonia.The presence of ground-glass opacity,reticulation,and bronchial wall thickening(all P>0.05)were common in both groups.Conclusions:Analysis of consolidation,nodules,and halo signs may contribute to the diferential diagnosis of pneumocystis pneumonia or cytomegalovirus pneumonia.However,some CT features considered typical in one or other diseases appear with similar frequency in both cohorts of AIDS patients.CT features are potentially useful for the diferential diagnosis of pneumocystis pneumonia and cytomegalovirus pneumonia in AIDS patients.
