The whole airspace phased array telemetry,track and command(TT&C)system is regarded as the development tendency of next generation TT&C system,and the distribution of the antenna units and the beamforming tech...The whole airspace phased array telemetry,track and command(TT&C)system is regarded as the development tendency of next generation TT&C system,and the distribution of the antenna units and the beamforming technology have sparked wide interest in this field.A method for antenna distribution is proposed based on the linear subarrays technology.A symmetrical truncated cone conformal array is composed of the linear subarrays placed on the generatrix.The impact of truncated cone bottom radius and elevation angle on beamforming are studied and simulated.Simulation results verify the system design.展开更多
Currently, TT&C of spacecraft is performed by a ground system. Because more and more spacecrafts are launched into orbits, it is difficult for the ground system to meet the TT&C requirements of the spacecrafts...Currently, TT&C of spacecraft is performed by a ground system. Because more and more spacecrafts are launched into orbits, it is difficult for the ground system to meet the TT&C requirements of the spacecrafts. To explore a new, effective and economical TT&C mode is absolutely necessary. A method is proposed to use SGBM mode in TT&C spacecrafts in low earth orbits, here. Firstly, the principle of the mode is discussed; secondly, the system to simulate the mode is designed; thirdly, the relative issues to use the mode are indicated; fourthly, the experimental results (simulation) to apply the mode to TT&C spacecrafts are analyzed; and finally dawn is the main conclusion of the method.展开更多
目的报道1例在鞍区精原细胞瘤放化疗后出现C型尼曼-匹克病(Niemann-Pick disease type C,NPC)的病例,加强对尼曼-匹克病(Niemann-Pick disease,NPD)的了解。方法对南部战区总医院内分泌科2021年6月收治的1例鞍区精原细胞瘤切除术、放化...目的报道1例在鞍区精原细胞瘤放化疗后出现C型尼曼-匹克病(Niemann-Pick disease type C,NPC)的病例,加强对尼曼-匹克病(Niemann-Pick disease,NPD)的了解。方法对南部战区总医院内分泌科2021年6月收治的1例鞍区精原细胞瘤切除术、放化疗后逐渐出现垂体功能减退、重度肝损害、肝脾大,激素替代治疗后引起继发性糖尿病的青少年患者长达4年的病史进行回顾性分析。结果本例患者为青少年女性,鞍区精原细胞瘤切除术及放化疗后,逐渐出现不同程度血细胞下降、脂代谢异常、肝功能异常、肝脾增大等,行骨髓穿刺,形态学发现2%尼曼-匹克细胞,最终诊断为NPC。经输血、护肝、胰岛素降糖、激素替代等对症治疗后,各项指标较治疗前好转,精神较入院时稍好转,但患者仍存在黄疸、肝脾大,偶有精神异常。目前继续门诊随访,予对症治疗。结论对于颅内肿瘤术后或放化疗后所致内分泌与代谢相关症状,且同时伴有难以解释的神经、精神、脏器功能异常时,要考虑到NPC的可能性,可通过骨髓穿刺涂片发现尼曼-匹克细胞初步诊断。目前NPC的治疗以对症为主。展开更多
With the rapid increase of number and types of Low Earth Orbit (LEO) and Medium Earth Orbit (MEO) spacecrafts in China, the insufficiency of TT&C resources is exposed.How to improve LEO and MEO TT&C coverage r...With the rapid increase of number and types of Low Earth Orbit (LEO) and Medium Earth Orbit (MEO) spacecrafts in China, the insufficiency of TT&C resources is exposed.How to improve LEO and MEO TT&C coverage rate has become the key problem of TT&C system,which should be resolved urgently. Firstly,the basic concepts of TT&C coverage are discussed and the relation between TT&C coverage of ground station and geography latitude of ground station as well as spacecraft altitude are analyzed. Secondly,the United States NASA TT&C network is taken as an instance to describe the developing process of TT&C network. Finally,in combination with TT&C activities of LEO and MEO spacecrafts in China,the method to heighten TT&C coverage rate is put forward,such as rational establishing station,space resources application,international TT&C cooperation etc.展开更多
AIM To investigate the role of bloodtransfusion in TT viral infection(TTV).METHODS We retrospectively studied serumsamples from 192 transfusion recipients whounderwent cardiovascular surgery and bloodtransfusion betwe...AIM To investigate the role of bloodtransfusion in TT viral infection(TTV).METHODS We retrospectively studied serumsamples from 192 transfusion recipients whounderwent cardiovascular surgery and bloodtransfusion between July 1991 and June 1992.Allpatients had a follow-up every other week for atleast 6 months after transfusion.Eightyrecipients received blood before screeningdonors for hepatitis C antibody(anti-HCV),and112 recipients received screened blood.Recipients with alanine aminotransferase level】2.5 times the upper normal limit were testedfor serological markers for viral hepatitis A,B,C,G,Epstein-Barr virus and cytomegalovirus.TTV infection was defined by the positivity forserum TTV DNA using the polymerase chainreaction method.RESULTS Eleven and three patients,whoreceived anti-HCV unscreened and screened'blood,respectively,had serum ALT levels】90 IU/L.Five patients(HCV and TTV:1;HCV,HGV,and TTV:1;TTV:2;and CMV and TTV:1)were positive for TTV DNA,and four of them hadsero-conversion of TTV DNA.CONCLUSION TTV can be transmitted viablood transfusion.Two recipients infected byTTV alone may be associated with the hepatitis.However,whether TTV was the causal agentremains unsettled,and further studies arenecessary to define the role of TTV infection inchronic hepatitis.展开更多
The tracking, telemetry and command （TT＆C） mission is extremely reliable for its characters of small time horizon and high redundancy. The combined forcing and failure biasing （CFFB） method that is usually used f...The tracking, telemetry and command （TT＆C） mission is extremely reliable for its characters of small time horizon and high redundancy. The combined forcing and failure biasing （CFFB） method that is usually used for simulating the unreliability of the highly dependable mission system seems not so efficient for the TT＆C mission. The concept about the importance of failure transition is proposed based on the logical relationship between TT＆C mission and its involved resources. Then, the importance is used for readjusting the transition rate of the failure transition when using the forcing and failure biasing during the simulation. Examples show that the improved CFFB method can evidently increase the occurrence of the TT＆C mission failure event and decrease the sample variance. More redundancy of the TT＆C mission leads to the improved CFFB method more efficient.展开更多
文摘The whole airspace phased array telemetry,track and command(TT&C)system is regarded as the development tendency of next generation TT&C system,and the distribution of the antenna units and the beamforming technology have sparked wide interest in this field.A method for antenna distribution is proposed based on the linear subarrays technology.A symmetrical truncated cone conformal array is composed of the linear subarrays placed on the generatrix.The impact of truncated cone bottom radius and elevation angle on beamforming are studied and simulated.Simulation results verify the system design.
文摘Currently, TT&C of spacecraft is performed by a ground system. Because more and more spacecrafts are launched into orbits, it is difficult for the ground system to meet the TT&C requirements of the spacecrafts. To explore a new, effective and economical TT&C mode is absolutely necessary. A method is proposed to use SGBM mode in TT&C spacecrafts in low earth orbits, here. Firstly, the principle of the mode is discussed; secondly, the system to simulate the mode is designed; thirdly, the relative issues to use the mode are indicated; fourthly, the experimental results (simulation) to apply the mode to TT&C spacecrafts are analyzed; and finally dawn is the main conclusion of the method.
文摘目的报道1例在鞍区精原细胞瘤放化疗后出现C型尼曼-匹克病(Niemann-Pick disease type C,NPC)的病例,加强对尼曼-匹克病(Niemann-Pick disease,NPD)的了解。方法对南部战区总医院内分泌科2021年6月收治的1例鞍区精原细胞瘤切除术、放化疗后逐渐出现垂体功能减退、重度肝损害、肝脾大,激素替代治疗后引起继发性糖尿病的青少年患者长达4年的病史进行回顾性分析。结果本例患者为青少年女性,鞍区精原细胞瘤切除术及放化疗后,逐渐出现不同程度血细胞下降、脂代谢异常、肝功能异常、肝脾增大等,行骨髓穿刺,形态学发现2%尼曼-匹克细胞,最终诊断为NPC。经输血、护肝、胰岛素降糖、激素替代等对症治疗后,各项指标较治疗前好转,精神较入院时稍好转,但患者仍存在黄疸、肝脾大,偶有精神异常。目前继续门诊随访,予对症治疗。结论对于颅内肿瘤术后或放化疗后所致内分泌与代谢相关症状,且同时伴有难以解释的神经、精神、脏器功能异常时,要考虑到NPC的可能性,可通过骨髓穿刺涂片发现尼曼-匹克细胞初步诊断。目前NPC的治疗以对症为主。
文摘With the rapid increase of number and types of Low Earth Orbit (LEO) and Medium Earth Orbit (MEO) spacecrafts in China, the insufficiency of TT&C resources is exposed.How to improve LEO and MEO TT&C coverage rate has become the key problem of TT&C system,which should be resolved urgently. Firstly,the basic concepts of TT&C coverage are discussed and the relation between TT&C coverage of ground station and geography latitude of ground station as well as spacecraft altitude are analyzed. Secondly,the United States NASA TT&C network is taken as an instance to describe the developing process of TT&C network. Finally,in combination with TT&C activities of LEO and MEO spacecrafts in China,the method to heighten TT&C coverage rate is put forward,such as rational establishing station,space resources application,international TT&C cooperation etc.
文摘AIM To investigate the role of bloodtransfusion in TT viral infection(TTV).METHODS We retrospectively studied serumsamples from 192 transfusion recipients whounderwent cardiovascular surgery and bloodtransfusion between July 1991 and June 1992.Allpatients had a follow-up every other week for atleast 6 months after transfusion.Eightyrecipients received blood before screeningdonors for hepatitis C antibody(anti-HCV),and112 recipients received screened blood.Recipients with alanine aminotransferase level】2.5 times the upper normal limit were testedfor serological markers for viral hepatitis A,B,C,G,Epstein-Barr virus and cytomegalovirus.TTV infection was defined by the positivity forserum TTV DNA using the polymerase chainreaction method.RESULTS Eleven and three patients,whoreceived anti-HCV unscreened and screened'blood,respectively,had serum ALT levels】90 IU/L.Five patients(HCV and TTV:1;HCV,HGV,and TTV:1;TTV:2;and CMV and TTV:1)were positive for TTV DNA,and four of them hadsero-conversion of TTV DNA.CONCLUSION TTV can be transmitted viablood transfusion.Two recipients infected byTTV alone may be associated with the hepatitis.However,whether TTV was the causal agentremains unsettled,and further studies arenecessary to define the role of TTV infection inchronic hepatitis.
基金supported by the National Natural Science Foundation of China (71071159)
文摘The tracking, telemetry and command （TT＆C） mission is extremely reliable for its characters of small time horizon and high redundancy. The combined forcing and failure biasing （CFFB） method that is usually used for simulating the unreliability of the highly dependable mission system seems not so efficient for the TT＆C mission. The concept about the importance of failure transition is proposed based on the logical relationship between TT＆C mission and its involved resources. Then, the importance is used for readjusting the transition rate of the failure transition when using the forcing and failure biasing during the simulation. Examples show that the improved CFFB method can evidently increase the occurrence of the TT＆C mission failure event and decrease the sample variance. More redundancy of the TT＆C mission leads to the improved CFFB method more efficient.
