利用“双星”系统建立初级数据中继卫星系统（TDRSS）的探讨

本文介绍了在“双星”系统的中继星上增加一个２．５ｍ直径Ｓ波段跟踪天线和２个转发器，与地面站一起构成初级ＴＤＲＳＳ系统。可以提供对飞船跟踪与通信的７０％以上的轨道覆盖率和２Ｍｂｐｓ的反向数传速率，解决了只依靠大量地面布站所面临的许多困难。

“双星”增强系统近空间伪卫星布站设计

布设近空间伪卫星可改善“双星”星座构型,实现无源定位,达到GDOP的最小化。从剖析GDOP的内涵出发,针对“双星”星座和近空间伪卫星特点,运用空间解析几何及矢量代数知识,推导出一种直接判断伪卫星空间位置的布站算法。该算法从几何角度,直观地确定近空间伪卫星的最佳布设点,具有简便、快捷、直观、形象的特点。不仅解决了“双星”增强系统的关键技术,也为近空间平台的应用提供了相关技术储备。

Salt-Containing Extractive Distillation of 1-Propanol/Water System 1.Prediction of Salt Effect on Vapor Liquid Equilibrium

This paper has studied the vapor-liquid equilibrium （VLE） for the salt-containing extractive distillation of the 1-propanol/water system. Binary VLE data were measured for the systems of 1-propanol （1）/KAc （4）, ethanediol （3）/KAc （4）, and 1-propanol （1）/ethanediol （3）, with the VLE data correlated with the NRTL model in order to obtain the model parameters of these binary systems. The binary VLE data cited in technical literature were correlated to obtain the model parameters for other binary systems. VLE data of ternary and quaternary systems predicted by the NRTI.： model agreed well with the literature data. The influence of KAc, ethanediol, and the KAc/ethanediol mixture on volatility between 1-propanol and water was investigated respectively. Test results showed that the above-mentioned materials （KAc, ethanediol） and their mixture （KAc and ethanediol） have different influence on the volatility. When x3=0.5, and x4=0.05, the azeotropic point can be elimi- nated. The NRTL model method of salt-containing VLE is simple and effective for the prediction of the system＇s VLE data.

BEACON SYNCHRONIZATION TECHNOLOGY FOR “BEIDOU” TERRESTRIAL IMPROVEMENT SYSTEM

Synchronization is an essential technology in the radio navigation system. The technique for improving the “Beidou” positioning ability is presented through constituting the terrestrial improvement system, and the beacon synchronization of the improvement system with the “Beidou” one-way time transfer model is realized.The direct digital synthesis (DDS) is adopted to generate the pseudo-random code clock having high precision and stability. Meanwhile, the CPLD device is used to design the synchronization pulse picking-up module, the spread spectrum PN code generator and the spread spectrum modulator. Measurement results indicate that the beacon synchronization has the high precision and the stability.

Vapor-Liquid Equilibrium of Ethyl Acetate+C_nH_(2n+1)OH(n=1,2,3) Binary Systems at 0.3 MPa

Vapor-liquid equilibrium data for the binary systems of ethyl acetate + methanol,ethyl acetate + ethanol and ethyl acetate + 1-propanol at 0.3 MPa were determined.The experimental data were verified with the point-to-point test of van Ness(1973).All these systems present an azeotropic point at 0.3 MPa that increases in ester composition for longer alcohol chains.The UNIFAC in different versions and ASOG prediction models were applied.

Corona-Support for the Entirety of High Energetic Disk

Based on results obtained from the study for MHD （magneto-hydrodynamics） of advective accretion disk, which are applied to real source showing typical values for CBS （close binary star-system）, it will investigate on self-structuring in the disk under the impact of the distribution of leading parameters （density, velocity ...）. The paper is considering the problem of development of the corona and will analyze the process of interaction of the plasma with the magnetic field in connection to support for the instabilities.

Filter Method and Its Consistency of Double-Star Position/SINS Integrated System

According to the characteristic of Beidou Double-star positing system (for short: Double-star position), the optimal predication model of Double-star position/SINS integrated system is put forward, which can make use of the delayed position in-formation from Double-star positioning system to predicate optimally for the integrated system, and then to correct SINS, and af-fords integrated results of some navigation parameters. In order to validate the consistency of the filter, the criteria for consistency of a filter is also studied, and the tested statistics are given, the experiment based on practical measured data shows that the filtering method is consistent with the integrated system.

A GPS/BDS dual-mode positioning algorithm for a train based on CIPSO_EKF

When using global positioning system/BeiDou navigation satellite(GPS/BDS)dual-mode navigation system to locate a train,Kalman filter that is used to calculate train position has to be adjusted according to the features of the dual-mode observation.Due to multipath effect,positioning accuracy of present Kalman filter algorithm is really low.To solve this problem,a chaotic immune-vaccine particle swarm optimization_extended Kalman filter(CIPSO_EKF)algorithm is proposed to improve the output accuracy of the Kalman filter.By chaotic mapping and immunization,the particle swarm algorithm is first optimized,and then the optimized particle swarm algorithm is used to optimize the observation error covariance matrix.The optimal parameters are provided to the EKF,which can effectively reduce the impact of the observation value oscillation caused by multipath effect on positioning accuracy.At the same time,the train positioning results of EKF and CIPSO_EKF algorithms are compared.The eastward position errors and velocity errors show that CIPSO_EKF algorithm has faster convergence speed and higher real-time performance,which can effectively suppress interference and improve positioning accuracy.

The fast rotation of companions of compact objects in close binary systems

We have performed Monte Carlo simulations of the rotation of single stars and companions of compact objects(The compact objects are white dwarfs(WDs) and neutron stars(NSs)) in close binaries.We present a comparison between the rotation of companions of compact objects and that of single stars.We find that the rotation of the companions of compact objects is on average faster than that of the single stars.According to the distribution of the orbital period and the rotation angular velocity,we find that the rotation of the companions of compact objects is mostly accelerated by stable mass transfer.Tidal forces of the compact object can also affect the rotation of companion.

A test of an early-type contact binary model by comparing the relations obtained from theory with those from observations

Contact binary systems,including massive,middle-mass and low-mass systems,have been observed.It is necessary to construct the evolutionary model for contact binary systems with all different masses.The model introduced by Huang,Song and Bi indicates some special and unique understandings of the physical processes occurring in the contact binaries.It is necessary to test whether this model can be applied to the early-type contact binaries.The best way to test a theoretical model is to know whether this model can explain the observational phenomena of such binaries.For this aim,a comparison is performed for the relations of mass-luminosity,mass-radius,and the distribution in the HR diagram obtained from the model introduced by Huang et al.and those from the astronomical observations.A good result is obtained by the comparison.This means the model can be used in calculating the evolution of early-type contact binaries,and can explain the observational phenomena of such binaries.

Contact binaries:I.An inspection of the HSB contact binary model by comparison of relationships obtained from theoretical light curves with that from astronomical observations

The light curve is one of the most important photometric characteristics of variable stars,which can supply physical information about many stars.So,light curves are the best candidate to inspect a theoretical model of binaries.One important feature of the light curve is the difference of two light minima of the light curve,namely the difference between the primary eclipse depth and the secondary eclipse depth(DED).In this paper,the secondary eclipse depths of theoretical and observational light curves are studied.Firstly,a method to calculate the theoretical light curves of an eclipsing binary with non-spherical components is proposed,which can be put into the HSB contact binary model [Huang R Q,et al.Chin J Astron Astrophys,2007,7:235-244;Song H F,et al.Chin J Astron Astrophys,2007,7:539-550].Theoretical light curves and the DED of the binary can be obtained at every evolutionary phase.The relationships of DED with mass and luminosity are presented and show special features for the contact binaries.Secondly,a large amount of observational data is collected,from which 11 massive,intermediate-mass contact binaries and 9 low-mass contact binaries are chosen and the two relationships are obtained using theoretical light curves.Finally,in order to check whether the HSB contact binary model can be used in contact binary systems with massive,intermediate-mass and low-mass components,a comparison is performed for the above mentioned relationships obtained from theoretical light curves with those from the astronomical observations.The results show a good agreement for contact binary systems with all different masses.

Applications of two-way satellite time and frequency transfer in the BeiDou navigation satellite system

A two-way satellite time and frequency transfer(TWSTFT) device equipped in the BeiDou navigation satellite system(BDS)can calculate clock error between satellite and ground master clock. TWSTFT is a real-time method with high accuracy because most system errors such as orbital error, station position error, and tropospheric and ionospheric delay error can be eliminated by calculating the two-way pseudorange difference. Another method, the multi-satellite precision orbit determination(MPOD)method, can be applied to estimate satellite clock errors. By comparison with MPOD clock estimations, this paper discusses the applications of the BDS TWSTFT clock observations in satellite clock measurement, satellite clock prediction, navigation system time monitor, and satellite clock performance assessment in orbit. The results show that with TWSTFT clock observations, the accuracy of satellite clock prediction is higher than MPOD. Five continuous weeks of comparisons with three international GNSS Service(IGS) analysis centers(ACs) show that the reference time difference between BeiDou time(BDT) and golbal positoning system(GPS) time(GPST) realized IGS ACs is in the tens of nanoseconds. Applying the TWSTFT clock error observations may obtain more accurate satellite clock performance evaluation in the 104 s interval because the accuracy of the MPOD clock estimation is not sufficiently high. By comparing the BDS and GPS satellite clock performance, we found that the BDS clock stability at the 103 s interval is approximately 10.12, which is similar to the GPS IIR.

Effects from Periastron Advance of Eccentric Binary Stars

In this paper,we discuss the coefficients of Gravitational waveform due to eccentric binaries periastron advance with evolved eccentricity.For the basic harmonic modes(n ≤ 5),the frequency split and corresponding relative strengths in the spectrum are figured out.Taking the well known binary systems PSRB 1913+16 and PSRB 1534+12 as examples,we study the dominant harmonic and its frequency split caused by periastron advance in the spectra,and give an estimation of detectability for PSRB 1913+16 and PSRB 1534+12,which are the promising targets for space observatories of gravitational wave.

On the non-synchronous rotation of binary systems

During the evolution of the binary system, many physical processes occur, which can influence the orbital angular velocity and the spin angular velocities of the two components, and influence the non-synchronous or synchronous rotation of the system. These processes include the transfer of masses and angular momentums between the component stars, the loss of mass and angular momentum via stellar winds, and the deformation of the structure of component stars. A study of these processes indicates that they are closely related to the combined effects of tide and rotation. This means, to study the synchronous or non-synchronous rotation of binary systems, one has to consider the contributions of different physical processes simultaneously, instead of the tidal effect alone. A way to know whether the rotation of a binary system is synchronous or non-synchronous is to calculate the orbital angular velocity and the spin angular velocities of the component stars. If all of these angular velocities are equal, the rotation of the system is synchronous. If not, the rotation of the system is non-synchronous. For this aim, a series of equations are developed to calculate the orbital and spin angular velocities. The evolutionary calculation of a binary system with masses of 10M~ ＋ 6Me shows that the transfer of masses and angular momentums between the two components, and the deformation of the components structure in the semidetached or in the contact phase can change the rotation of the system from synchronous into non-synchronous rotation.

Hyperbolicity of C^1 -star invariant sets for C^1 -class dynamical systems

In this paper, we simply prove, in the framework of Liao, the hyperbolicity of C 1 -star invariant sets of C 1 -class differential systems on a closed manifold of dimension≤ 4, without using the C 1 -connecting lemma and even the ergodic closing lemma.