A novel microstructure fiber （MF） structure is proposed for broadband dispersion compensation. Through manipulating the four air-hole parameters and the pitch, the broad band dispersion compensation MF can be effici...A novel microstructure fiber （MF） structure is proposed for broadband dispersion compensation. Through manipulating the four air-hole parameters and the pitch, the broad band dispersion compensation MF can be efficiently designed. The newly designed MF could compensate （to within 0.8%） the dispersion of 101 times of its length of standard single mode fiber over the entire 100-nm band centered on 1550 nm. The proposed design has been simulated through the finite difference beam propagation method, and the corresponding design procedures are also presented. OCIS codes： 060.2310, 060.2280.展开更多
The 60-GHz traveling-wave tube （TWT） prevails nowadays as the amplifier for the satellite communication and electronic countermeasures. The folded waveguide （FW） is a promising all-metal slow-wave structure （SWS...The 60-GHz traveling-wave tube （TWT） prevails nowadays as the amplifier for the satellite communication and electronic countermeasures. The folded waveguide （FW） is a promising all-metal slow-wave structure （SWS） for the 60-GHz TWT with advantages of robust performance, fine heat dissipation, considerable power and bandwidth. A novel FW periodically loaded with rectangular grooves is analyzed for the purpose of gaining higher power and gain. The rf characteristics are investigated by numerical simulation, and the nonlinear large- signal performance of such a TWT is analyzed by a 3I） particle-in-cell code MAGIC. Compared with normal circuits, relatively higher continuous-wave power （40-56 W） and similar bandwidth （5 GHz） are predicted by simulation. Meanwhile, the designed operation voltage is 10.5 kV, which keeps the low-voltage advantage of the popular helix TWT competitor. The novel FW will favor the design of a broadband and high-power 60-GHz TWT展开更多
The stratosphere airship provides a unique and promising platform for earth observation. Researches on the project design and control scheme for earth observation platforms are still rarely documented. Nonlinear dynam...The stratosphere airship provides a unique and promising platform for earth observation. Researches on the project design and control scheme for earth observation platforms are still rarely documented. Nonlinear dynamics, model uncertainties, and external disturbances contribute to the difficulty in maneuvering the stratosphere airship. A key technical challenge for the earth observation platform is station keeping, or the ability to remain fixed over a geo-location. This paper investigates the conceptual design, modeling and station-keeping attitude control of the near-space earth observation platform. A conceptual design of the earth observation platform is presented. The dynamics model of the platform is derived from the Newton-Euler formulation, and the station-keeping control system of the platform is formulated. The station-keeping attitude control approach for the platform is proposed. The multi-input multi-output nonlinear control system is decoupled into three single-input single-output linear subsystems via feedback linearization, the attitude controller design is carried out on the new linear systems using terminal sliding mode control, and the global stability of the closed-loop system is proven by using the Lyapunov theorem. The performance of the designed control system is simulated by using the variable step Runge-Kutta integrator. Simulation results show that the control system tracks the commanded attitude with an error of zero, which verify the effectiveness and robustness of the designed control system in the presence of parametric uncertainties. The near-space earth observation platform has several advantages over satellites, such as high resolution, fast to deploy, and convenient to retrieve, and the proposed control scheme provides an effective approach for station-keeping attitude control of the earth observation platform.展开更多
由于新型苯二氮[艹卓]类策划药物具有用量小、药效强、体内代谢快和含量低等特点,很难在受害人的血液和尿液中检出,而毛发具有检出时效长、易获取和易保存的优势,因此提出了题示方法.取剪至1~2 mm的毛发20 mg,加入1 m L含内标(1μg.L^(...由于新型苯二氮[艹卓]类策划药物具有用量小、药效强、体内代谢快和含量低等特点,很难在受害人的血液和尿液中检出,而毛发具有检出时效长、易获取和易保存的优势,因此提出了题示方法.取剪至1~2 mm的毛发20 mg,加入1 m L含内标(1μg.L^(-1)阿普唑仑Gd5)提取剂,于-50℃预冷5min,冷冻研磨两次,每次90s,中间间隔60s,并离心5min,取上清液浓缩至干,用100μL甲醇复溶,经0.22μm有机滤膜过滤.滤液在Acquity UPLCHSST3色谱柱上进行分离,经不同体积比的0.1%(体积分数,下同)甲酸溶液G含0.1%甲酸的乙腈溶液的混合液为流动相进行梯度洗脱,采用电喷雾离子源正离子模式(ESI+)扫描,多反应监测(MRM)模式检测,以保留时间和特征离子定性,内标法定量.结果表明,7种新型苯二氮[艹卓]类策划药物(瑞马唑仑、科纳唑仑、氟阿普唑仑、氟溴唑仑、玻玛唑仑、依替唑仑、溴替唑仑)工作曲线的线性范围为1~500pg.mg^(-1),检出限(3S/N)为0.11~0.35pg.mg^(-1).按照标准加入法进行回收试验,回收率为90.2%~104%,日内精密度和日间精密度试验所得相对峰面积的相对标准偏差(n=6)分别为1.7%~4.7%和2.9%~7.0%.展开更多
基金This work was supported by the National Basic Research Program of China (No. 2003CB314900) the Key Grant Project of Chinese Ministry of Education (No. 104046)
文摘A novel microstructure fiber （MF） structure is proposed for broadband dispersion compensation. Through manipulating the four air-hole parameters and the pitch, the broad band dispersion compensation MF can be efficiently designed. The newly designed MF could compensate （to within 0.8%） the dispersion of 101 times of its length of standard single mode fiber over the entire 100-nm band centered on 1550 nm. The proposed design has been simulated through the finite difference beam propagation method, and the corresponding design procedures are also presented. OCIS codes： 060.2310, 060.2280.
基金Supported by the National Natural Science Foundation of China under Grant No 61271029the National Science Fund for Distinguished Young Scholars of China under Grant No 61125103the National Research Foundation of Korea under Grant No MSIP:NRF-2009-0083512
文摘The 60-GHz traveling-wave tube （TWT） prevails nowadays as the amplifier for the satellite communication and electronic countermeasures. The folded waveguide （FW） is a promising all-metal slow-wave structure （SWS） for the 60-GHz TWT with advantages of robust performance, fine heat dissipation, considerable power and bandwidth. A novel FW periodically loaded with rectangular grooves is analyzed for the purpose of gaining higher power and gain. The rf characteristics are investigated by numerical simulation, and the nonlinear large- signal performance of such a TWT is analyzed by a 3I） particle-in-cell code MAGIC. Compared with normal circuits, relatively higher continuous-wave power （40-56 W） and similar bandwidth （5 GHz） are predicted by simulation. Meanwhile, the designed operation voltage is 10.5 kV, which keeps the low-voltage advantage of the popular helix TWT competitor. The novel FW will favor the design of a broadband and high-power 60-GHz TWT
基金supported by Hunan Provincial Innovation Foundation for Postgraduate(Grant No. CX2011B005)National University of Defense Technology Innovation Foundation for Postgraduate, China(GranNo. B110105)
文摘The stratosphere airship provides a unique and promising platform for earth observation. Researches on the project design and control scheme for earth observation platforms are still rarely documented. Nonlinear dynamics, model uncertainties, and external disturbances contribute to the difficulty in maneuvering the stratosphere airship. A key technical challenge for the earth observation platform is station keeping, or the ability to remain fixed over a geo-location. This paper investigates the conceptual design, modeling and station-keeping attitude control of the near-space earth observation platform. A conceptual design of the earth observation platform is presented. The dynamics model of the platform is derived from the Newton-Euler formulation, and the station-keeping control system of the platform is formulated. The station-keeping attitude control approach for the platform is proposed. The multi-input multi-output nonlinear control system is decoupled into three single-input single-output linear subsystems via feedback linearization, the attitude controller design is carried out on the new linear systems using terminal sliding mode control, and the global stability of the closed-loop system is proven by using the Lyapunov theorem. The performance of the designed control system is simulated by using the variable step Runge-Kutta integrator. Simulation results show that the control system tracks the commanded attitude with an error of zero, which verify the effectiveness and robustness of the designed control system in the presence of parametric uncertainties. The near-space earth observation platform has several advantages over satellites, such as high resolution, fast to deploy, and convenient to retrieve, and the proposed control scheme provides an effective approach for station-keeping attitude control of the earth observation platform.
