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No-go guide for the Hubble tension: Late-time solutions 期刊论文  OAI收割
PHYSICAL REVIEW D, 2022, 卷号: 105, 期号: 2, 页码: L021301
作者:  Cai, Rong-Gen;  Guo, Zong-Kuan;  Wang, Shao-Jiang;  Yu, Wang-Wei;  Zhou, Yong
  |  收藏  |  浏览/下载：24/0  |  提交时间：2023/01/16
A New Set of Parameters of High-Mass X-ray Binaries Found with their Cyclotron Lines 期刊论文  OAI收割
arXiv e-prints, 2018
作者:  Zhang, Chengmin;  Taani, Ali;  Chaty, Sylvain;  Karino, Shigeyuki;  Song, Liming
  |  收藏  |  浏览/下载：77/0  |  提交时间：2019/07/12
Astrophysics - High Energy Astrophysical Phenomena  Abstract: We have derived new physical quantities for several High-Mass X-ray Binaries (HMXBs) with supergiant (SG) companions through their cyclotron lines. The parameters are: the terminal velocity of the wind, the mass loss rate of the donor, the effective temperature and the magnetic fields. These parameters influence significantly the improvement of the model of accretion. In spite of the variety of their observational properties, the corresponding magnetic field is around B ~ 10^12 G. This result can be constrained by the effects on stellar evolution. In addition, we have performed a segmentation in the parameter space of donors intended for several SG-HMXB listed in our sample set. The parameter space can be categorized into five regimes depending on the possibility of disk formation associated with accretion from the stellar wind. This can give a quantitative clarification of the observed variability and the properties of these objects. We show that, when these systems come into the direct accretion region, systems with corresponding parameters can emit X-rays.  
Analyse the angular velocity estimation errors of -- filter based on high sampling rate (EI CONFERENCE) 会议论文  OAI收割
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
作者:  Zhang Y.
收藏  |  浏览/下载：31/0  |  提交时间：2013/03/25
In order to get angular velocity of stabilization servo mechanism from angular position sensors  -- filter based on high sampling rate was established  model and error characteristics were analyzed. With the hypothesis of constant acceleration  -- filter and its angular velocity transfer function were deduced. Combing with optimum parameters  the effects of and sample rate on the error characteristics were evaluated. According to the requirements of stabilization servo mechanism  the frequency characteristics of angular velocity transfer function are analyzed  and the filter parameters are designed. The experimental which filter tracked and smoothed sinusoidal signal  the results show that when the cutoff frequency of angular velocity loop is 44.9rad/s  sampling period and parameters are 0.08ms and 0.01279 respectively  the phase leading of angular position is 70. -- filter tracked sinusoidal signals with maximum angular velocity(30/s) and maximum angular acceleration(30/s2)  the error of angular velocity estimation was 0.053/s. In the engineering of electro-optical stabilization servo mechanism  -- filter can reduce noise effectively  and reached the requirement of platform angular velocity estimation. Also it is one of the effective methods to get angular velocity from angular position sensors. 2011 IEEE.  
The angular velocity estimation principal of -- filter based on high sampling rate (EI CONFERENCE) 会议论文  OAI收割
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
作者:  Zhang Y.
收藏  |  浏览/下载：30/0  |  提交时间：2013/03/25
In order to get angular velocity of stabilization servo mechanism from angular position sensors  -- filter and its angular velocity transfer function were predigested. Combing with optimum parameters  -- filter based on high sampling rate was established  the effect of and sample rate on filter nature frequency were evaluated. According to the requirements of stabilization platform  the principle of steady and transient tracking filter differential were proved. With the hypothesis of constant acceleration  the frequency characteristics of angular velocity transfer function were analyzed  three-dimensional Kalman filter was simplified  and the filter parameters were designed. The results show that when the spectrum of input signal was lower than 6rad/s  parameters was 0.02  and sampling period were 0.08ms and 0.1ms respectively  the filter can realize differential exactly  when the spectrum was 9rad/s  the precision was no less than 1.1%  the phase leading of angular position was no less than 70  the natural frequency should be higher than the cut-off frequency of stabilization platform was two or three times. In the engineering of electro-optical stabilization servo mechanism  -- filter has properties of tracking differential  and reached the requirement of platform angular velocity estimation. Also it is one of the effective methods to get angular velocity from angular position sensors. 2011 IEEE.  
Three-sample rotation vector algorithm with angular rate input (EI CONFERENCE) 会议论文  OAI收割
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
作者:  Zhang Y.
收藏  |  浏览/下载：22/0  |  提交时间：2013/03/25
In order to research the attitude algorithm with angular rate input under the conical motion  a optimal threesample rotation vector algorithm based on single-step Newton backward interpolation is proposed. Using the principle of limited rigid body rotation and the characteristic of angular rate input  three-sample rotation vector algorithm is derivated. To minimum attitude errors  three-sample rotation vector algorithm is optimized. Three angular rate extraction methods of singlestep entire sample recursion  multi-step entire sample and singlestep Newton backward interpolation are proposed. Under the condition of conical motion with semi-cone angle 3 and angular frequency 2rad/s  simulation is done. The simulation results show that single-step Newton backward interpolation is superior to the other two methods  and its maximum error peak is 0.01  error drift rate is 0.036/h. Experiments in three-axis flying turntable with the same parameters are carried out  and the results show that error drift rates of three-channels are less than those of traditional quaternion  which are 13.53%  12.08% and 23.68% lower respectively. It also verified that the new algorithm can perform a high accuracy under the conical motion. 2011 IEEE.  
A new method of target recognition based on rough set and support vector machine (EI CONFERENCE) 会议论文  OAI收割
2nd International Conference on Image Analysis and Signal Processing, IASP'2010, April 12, 2010 - April 14, 2010, Xiamen, China
作者:  He X.
收藏  |  浏览/下载：19/0  |  提交时间：2013/03/25
Stabilization for wireless sensor/actuator networks with reordering-based sample rate adaptation 会议论文  OAI收割
2010 International Conference on Electrical Engineering and Automatic Control (ICEEAC2010), Zibo, China, November 26-28, 2010
作者:  Li JN(李金娜);  Yu HB(于海斌);  Xie YH(谢彦红);  Pei XW(裴晓雯)
收藏  |  浏览/下载：15/0  |  提交时间：2012/06/06
A high-speed acquisition and processing system of the laser speckle signal on the magnetic fluid (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, June 17, 2009 - June 19, 2009, Beijing, China
作者:  Sun Y.;  Sun Y.;  Wan Q.-H.
收藏  |  浏览/下载：27/0  |  提交时间：2013/03/25
In order to achieve the dynamical detection and real-time analysis of the movement status of the magnetic fluid  according to the difficulties of the detection of the magnetic fluid  established a high-speed acquisition and processing system of laser speckle signal on the magnetic fluid. First of all  the FPGA (EP2C8T144C8N) drived the linear array CCD(TCD1501D) to scan in the corresponding time sequence given by the computer  collected the laser speckle interferometric image in rapid change on the surface of the magnetic fluid  which followed the movement of the magnetic fluid  and the signal collected by CCD was converted into the digital data through the high-speed A/D convertor and stored into the internal buffer FIFO of the FPGA  whose width and depth were designed by the user as required. Then  the FPGA sent the digital signal of the laser speckle interferometric images into the computer through the USB2.0 highspeed differential bus  whose transmission rate can reach 480Mb/s in theory. Finally  the distribution of the laser speckle on the magnetic fluid was messy and random  which carried certain information about the surface of the magnetic fluid  based on the theories of the statistic correlation and the subdivision of images  analysing and processing the laser speckle interferometric images  indirectly got the movement status of the magnetic fluid under the electromagnetic field. The experimental results show that: the High Speed Acquisition and Processing System has the advantage of full-court  non-contact  non-invasive  high-precision and high reliability and so on. The detection resolution of high speed acquisition and processing system is superior to 1m and the sample rate is 3Msps  which basically meets the requirements of the magnetic fluid movement state detection. 2009 SPIE.  
Application of CMOS APS star tracker with large FOV in attitude and angular velocity determination (EI CONFERENCE) 会议论文  OAI收割
Advanced Sensor Systems and Applications III, November 12, 2007 - November 14, 2007, Beijing, China
Lu D.; Guang J.; Shaoju W.; Tao C.
收藏  |  浏览/下载：30/0  |  提交时间：2013/03/25
The paper deals with the spacecraft attitude determination problem using a new kind of star tracker with large FOV based on CMOS APS. Star tracker has been developed since 1970s and proved to be the most accurate sensor ever used in the spacecraft attitude determination systems. But the traditional CCD star tracker also has some disadvantages  such as small FOV  high power consumption  low sample rate and low working angular rate limit which prevent the use of CCD star tracker in attitude large angle maneuvering process. The new kind of star tracker based on CMOS APS has no such disadvantages and is more applicable on modern low-cost agile small satellites. Its higher sample rate and working angular rate limit over traditional CCD star tracker make it more adapt for spacecraft angular velocity determination. Because of the large FOV of the star tracker  the mathematical model of traditional CCD star tracker with a small FOV is not appropriate. So a new mathematical model was quoted to fit the star tracker with a large FOV. An alternative adaptive algorithm was also introduced in the paper. It can help the EKF algorithm work lacking of accurate covariance of the observation noise. An optimal estimation algorithm was used to estimate the angular velocity directly from the star tracker measurements. Mathematic simulation results indicate the CMOS APS star tracker can give accurate attitude information and estimated angular rate. The method can be used as the chief attitude determination system design of low-cost satellite without gyros  or be used as a backup strategy in the event of gyro failures to enhance the reliability of the attitude determination system.  
False signal rates for the ((X)over-bar) control charts with runs tests when process parameters are estimated 期刊论文  OAI收割
COMMUNICATIONS IN STATISTICS-SIMULATION AND COMPUTATION, 2006, 卷号: 35, 期号: 4, 页码: 1045-1056
作者:  Yang, C.;  Tse, S. -K.;  Li, G.
  |  收藏  |  浏览/下载：17/0  |  提交时间：2018/07/30