Intra-body communication (IBC) is a technology using the human body as a transmission medium for electrical signals. Compared with the short distance wireless communication technologies, it has several novel character...Intra-body communication (IBC) is a technology using the human body as a transmission medium for electrical signals. Compared with the short distance wireless communication technologies, it has several novel characteristics. The modeling, simulation and implement of intra-body communication are reviewed. Firstly, the transfer function of the galvanic coupling IBC is deduced, and the in vivo measurements results and the corresponding mathematical simulations results based on the proposed transfer function are discussed. Secondly, a finite-element method for modeling the whole human body is introduced, and the simulation results of the galvanic coupling IBC based on the whole human body and the corresponding in vivo measurement results are discussed. Finally, the implement methods of the intra-body communication as well as a novel IBC system based on Mach-Zehnder EO modulator are introduced and analyzed, while some conclusions are achieved.展开更多
A new concept stratospheric aerostat is investigated which consists of a saucer-shaped hull, multi-vectored thrusters, and an under-slung nacelle. The design of this aerostat involves tradeoffs between conventional ai...A new concept stratospheric aerostat is investigated which consists of a saucer-shaped hull, multi-vectored thrusters, and an under-slung nacelle. The design of this aerostat involves tradeoffs between conventional airship and high altitude balloon. The sling connection simplifies structure design significantly, but brings challenges for dynamics analysis. Dynamics modeling for this aerostat is a kind of double-body problem with geometric constraint. Nonlinear dynamics model is established by considering the effects of under-slung nacelle. Oscillation behavior of this double-body system is superposed by a long-period oscillation of the hull and a short-period oscillation of the nacelle. The length of sling only influences the short-period oscillation but the mass ratio of nacelle to main body determines the stability of system. Finally, an envelope about mass ratio and maximal open loop forward thrust as well as speed is presented, where the system is stable.展开更多
Two classes of composite materials are considered: classical metaleceramic composites with reinforcing hard inclusions as well as hard ceramics matrix with soft gel inclusions. Movable cellular automaton method is use...Two classes of composite materials are considered: classical metaleceramic composites with reinforcing hard inclusions as well as hard ceramics matrix with soft gel inclusions. Movable cellular automaton method is used for modeling the mechanical behaviors of such different heterogeneous materials. The method is based on particle approach and may be considered as a kind of discrete element method. The main feature of the method is the use of many-body forces of inter-element interaction within the formalism of simply deformable element approximation. It was shown that the strength of reinforcing particles and the width of particle-binder interphase boundaries had determining influence on the service characteristics of metaleceramic composite. In particular, the increasing of strength of carbide inclusions may lead to significant increase in the strength and ultimate strain of composite material. On the example of porous zirconia ceramics it was shown that the change in the mechanical properties of pore surface leads to the corresponding change in effective elastic modulus and strength limit of the ceramic sample. The less is the pore size, the more is this effect. The increase in the elastic properties of pore surface of ceramics may reduce its fracture energy.展开更多
目的评估抑郁症患者中体质量指数(body mass index,BMI)正常、超重和代谢综合征(metabolic syndrome,MetS)的转移规律。方法以2016年1月至2021年11月期间于首都医科大学附属北京安定医院治疗,有多次入院记录的抑郁症患者为研究对象,根...目的评估抑郁症患者中体质量指数(body mass index,BMI)正常、超重和代谢综合征(metabolic syndrome,MetS)的转移规律。方法以2016年1月至2021年11月期间于首都医科大学附属北京安定医院治疗,有多次入院记录的抑郁症患者为研究对象,根据每次入院时BMI和代谢情况分为BMI正常、超重和代谢综合征3种状态,采用多状态Markov模型分析转移规律。结果纳入398例研究对象的892条观测记录,中位年龄56岁,中位随访时间40个月。结果显示3种状态间共发生494次转移,其中5.1%由BMI正常转移为超重,5.5%由超重转移为MetS。超重发展为MetS的转移强度最高,是超重变为BMI正常的9.52倍。48.53个月后,BMI正常的抑郁症患者开始转移为MetS。对于超重的患者,8.77个月后开始转移为MetS。36个月后,BMI正常或超重者转移为MetS的概率为31.4%和50.4%;对于合并MetS者,36个月后仍为MetS的概率为51.2%。多因素分析显示未婚是体质量正常的抑郁症患者转移为超重的危险因素,而具有较高的受教育程度是超重的抑郁症患者转移为MetS的保护因素。结论抑郁症患者发展为MetS的强度和风险较高,发生MetS后不易好转,提示加强抑郁症患者的BMI管理和MetS的干预。展开更多
文摘Intra-body communication (IBC) is a technology using the human body as a transmission medium for electrical signals. Compared with the short distance wireless communication technologies, it has several novel characteristics. The modeling, simulation and implement of intra-body communication are reviewed. Firstly, the transfer function of the galvanic coupling IBC is deduced, and the in vivo measurements results and the corresponding mathematical simulations results based on the proposed transfer function are discussed. Secondly, a finite-element method for modeling the whole human body is introduced, and the simulation results of the galvanic coupling IBC based on the whole human body and the corresponding in vivo measurement results are discussed. Finally, the implement methods of the intra-body communication as well as a novel IBC system based on Mach-Zehnder EO modulator are introduced and analyzed, while some conclusions are achieved.
基金Projects(61175074,11272205)supported by the National Natural Science Foundation of China
文摘A new concept stratospheric aerostat is investigated which consists of a saucer-shaped hull, multi-vectored thrusters, and an under-slung nacelle. The design of this aerostat involves tradeoffs between conventional airship and high altitude balloon. The sling connection simplifies structure design significantly, but brings challenges for dynamics analysis. Dynamics modeling for this aerostat is a kind of double-body problem with geometric constraint. Nonlinear dynamics model is established by considering the effects of under-slung nacelle. Oscillation behavior of this double-body system is superposed by a long-period oscillation of the hull and a short-period oscillation of the nacelle. The length of sling only influences the short-period oscillation but the mass ratio of nacelle to main body determines the stability of system. Finally, an envelope about mass ratio and maximal open loop forward thrust as well as speed is presented, where the system is stable.
基金the Projects Nos. III.23.2.3 (I.S. Konovalenko, S.P. Buyakova) and III.23.2.4 (S.G. Psakhie) of the Basic Scientific Research Program of State Academies of Sciences for 2013e2020the RFBR Project No. 12-01-00805-a (A.Yu. Smolin, E.V. Shilko)the grant No. 14-19-00718 of the Russian Science Foundation (A.Yu. Smolin, E.V. Shilko, S.V. Astafurov)
文摘Two classes of composite materials are considered: classical metaleceramic composites with reinforcing hard inclusions as well as hard ceramics matrix with soft gel inclusions. Movable cellular automaton method is used for modeling the mechanical behaviors of such different heterogeneous materials. The method is based on particle approach and may be considered as a kind of discrete element method. The main feature of the method is the use of many-body forces of inter-element interaction within the formalism of simply deformable element approximation. It was shown that the strength of reinforcing particles and the width of particle-binder interphase boundaries had determining influence on the service characteristics of metaleceramic composite. In particular, the increasing of strength of carbide inclusions may lead to significant increase in the strength and ultimate strain of composite material. On the example of porous zirconia ceramics it was shown that the change in the mechanical properties of pore surface leads to the corresponding change in effective elastic modulus and strength limit of the ceramic sample. The less is the pore size, the more is this effect. The increase in the elastic properties of pore surface of ceramics may reduce its fracture energy.
文摘目的评估抑郁症患者中体质量指数(body mass index,BMI)正常、超重和代谢综合征(metabolic syndrome,MetS)的转移规律。方法以2016年1月至2021年11月期间于首都医科大学附属北京安定医院治疗,有多次入院记录的抑郁症患者为研究对象,根据每次入院时BMI和代谢情况分为BMI正常、超重和代谢综合征3种状态,采用多状态Markov模型分析转移规律。结果纳入398例研究对象的892条观测记录,中位年龄56岁,中位随访时间40个月。结果显示3种状态间共发生494次转移,其中5.1%由BMI正常转移为超重,5.5%由超重转移为MetS。超重发展为MetS的转移强度最高,是超重变为BMI正常的9.52倍。48.53个月后,BMI正常的抑郁症患者开始转移为MetS。对于超重的患者,8.77个月后开始转移为MetS。36个月后,BMI正常或超重者转移为MetS的概率为31.4%和50.4%;对于合并MetS者,36个月后仍为MetS的概率为51.2%。多因素分析显示未婚是体质量正常的抑郁症患者转移为超重的危险因素,而具有较高的受教育程度是超重的抑郁症患者转移为MetS的保护因素。结论抑郁症患者发展为MetS的强度和风险较高,发生MetS后不易好转,提示加强抑郁症患者的BMI管理和MetS的干预。
