The origin of the slow solar wind has been a puzzle in the field of space physics for many years. Some researchers suggest that Alfvenic slow winds originate from small coronal holes or at the boundary of coronal holes, although others have found that Alfvenic slow winds does not differ in compositions from the non-Alfvenic slow wind. A small coronal hole wind embedded in the slow solar wind is reported recently, but of lower Alfvenicity. We calculated the propagation of small coronal hole winds and Alfven waves using a simple two-dimensional solar wind model; the results show that the Alfven waves are separated from the co-originated plasma during the propagation, leading to small coronal hole winds with low Alfvenicity and ordinary slow winds with high Alfvenicity. This result qualitatively explains the properties of the small coronal hole winds and Alfvenic slow wind with normal slow wind properties. This study provides a new insight into the origin of the slow solar wind mystery.

针对多优先级天文观测卫星任务动态规划问题,分析了高优先级任务动态插入以及未知事件中断原任务规划方案执行的情况,研究了原任务规划方案相应的动态规划问题.在关于SVOM （Space multi-band Variable Object Monitor）卫星任务规划系统的研究中,针对单星机遇目标任务重规划问题,提出一种基于滚动优化策略的任务重规划求解方案.在每个滚动周期内,优先安排高优先级动态到达任务,回滚处理原方案中受未知事件和高优先级机遇目标影响的任务,或者删除原方案中受影响的任务.目标函数综合考虑了全年卫星任务规划总时长和机遇目标的规划总时长.仿真验证结果表明,本文设计方法对于快速响应高优先级机遇目标以及提高服务质量具有一定意义.

基于Polar卫星1996-2008年的表面电压数据，研究了卫星在低轨区域出现正高电位（异常事件）与太阳活动的关系及其发生位置的磁地方时（MLT）分布.研究表明:太阳辐射与异常事件发生次数呈正相关，太阳活动越活跃，异常事件出现次数越多，但不会影响航天器表面电位；异常事件发生占比呈现明显季节性变化，在太阳活动高年，冬季和夏季次数较多，春季和秋季次数较少，在太阳活动低年，每月次数均维持在较低水平，而一个月内异常事件次数没有明显规律；在分布上南北半球表现出相似性，异常事件均不会发生在地磁纬度50°-60°区域，极区和昏侧发生次数较多，而不同的是异常事件在南半球发生得更多更集中；虽然太阳活动与航天器在低高度时表面出现正高电位的次数呈正相关，但即使在太阳活动峰年，航天器异常事件发生率也不超过10%.

The miniature and integrated design is a main trend in science payload development for deep space. An integrated ion and neutral particle analyzer is built for Chinese Mars exploration project. The measurements of ion and energetic neutral atom share the sensor and electronics and are integrated in a single instrument with lower mass and power. Electrostatic analyzing method is used to measure the ions'energy and direction. Time of flight method is used to measure the ions species. The energetic neutral atoms are ionized firstly and the same measurement method with ions. The qualification model is calibrated and the results fulfill the requirements for the Mars project.

问题描述 空间天气是指从太阳表面、日地空间到地球磁场、高层大气中能够影响天地基技术系统性能与可靠性,危及人类健康与生命的变化的物质条件综合状况.而太阳爆发活动、电离层扰动事件和地磁暴均会产生破坏,严重影响社会正常运转.

Thermal ion mass discrimination is one of the key techniques for the space plasma detection.In order to measure the energy spectra and composition of space plasma,the Thermal Ion Mass Spectrometer (TIMS) utilizes a hemisphere electrostatic analyzer accompanied with a time of flight unit based on ultra-thin carbon foil.It has been used broadly in space plasma measurement.Three key techniques,such as 5 mV high resolution sweeping high voltage,10～20nm ultra-thin carbon foil treatment,and 30kV acceleration high voltage,have been resolved in the process of TIMS development.The prototype of TIMS has been calibrated by the calibration system in the University of Bern.The calibration results show that the performances of TIMS are as follows.The energy measurement range is from 0.499eV to 29.94keV,and the energy resolution is 10.5％.The field of view is 360° ×8.4°,and the angular resolution is 22.5°× 8.4°.The main ion species including H+,He+,O+ can be resolved.On the basis of the research work in this study,more advanced plasma instruments with higher mass resolution,larger field of view and more miniature design can be developed.

探索了固液火箭发动机作为上面级动力系统的性能特点;采用气瓶、贮箱和燃烧室并联布局的结构,有效减少了固液火箭发动机的长细比;建立了固液火箭发动机系统设计的数学模型,采用多岛遗传算法,开展了并联式固液火箭发动机总体方案的设计优化;优化结果与某固体火箭发动机上面级的比较说明,固液火箭发动机在上面级动力系统中具有较大的应用潜力.

2016年6月，中国科学院遴选出5个空间科学卫星项目，争取在2020年前后发射，“磁层-电离层-热层耦合”（MIT）小卫星星座探测计划就是其中之一。该计划对于深入理解空间天气的一些重要物理过程有着重要意义，与国际同领域的任务相比，他具有独特的切入点和创新思想。

Interplanetary Coronal mass ejections (CMEs) and corotating interaction regions (CIRs) are two types of most geoeffective solar wind transients and also the main drivers of geomagnetic storms. In this study, by using a superposed epoch analysis, we have compared the statistical features of solar wind parameters for the two types of solar disturbances during the 23rd solar cycle and the resulting changes of geomagnetic indices ( D st, AE, and K p ). Meanwhile, the statistics of solar wind parameters and geomagnetic indices corresponding to magnetic storms with different intensities are also investigated. In general, it is found that the slopes of linearly fitted N sw /P dyn curves (where N sw is the solar wind proton density and P dyn is the solar wind dynamic pressure) with respect to epoch time remains positive for CME events but negative for CIR events, which can act as a feasible means to distinguish CME and CIR events. On average, compared to CIR events, CME events have larger magnitudes of southward IMF B z , solar wind dynamic pressure, AE and K p indices but smaller D st min . In principle, CMEs bear higher possibility to drive extremely intense (i.e., super) geomagnetic storms. The overall variations of D st tend to be similar to some extent for different levels of geomagnetic storms, however, D st decreases faster for stronger storms.

The injector II RFQ accelerator of ADS is used to accelerate protons of 10 mA from 35 keV to 2.1 MeV. The cavity structure of the RFQ is the same as that of the SNS RFQ which has a square cross section, and it adopts π-mode rods to enhance the RF (radio frequency) stability of the cavity. Low power tests show that the flatness of the cavity is better than ±0.01 and the unloaded Q value is 13000. CW (continuous wave) working condition was realized after a long time conditioning of the cavity. Beam tests were conducted with a current of 10 mA in pulse mode and CW mode, respectively, and it indicates that the transmission efficiency is 95.3%, output energy is 2.165 MeV, energy spread is 1.9%, and the transverse and longitudinal emittances are all 0.33 πmm·mrad. ©, 2015, Atomic Energy Press. All right reserved.

极区从电离层到磁层的上行粒子流探测研究是空间天气建模中的重要问题,其起源和加速机制是磁层-电离层-热层耦合小卫星星座计划的主要科学目标.磁层-电离层热层耦合小卫星星座计划拟定由两颗磁层星和两颗电离层/热层星组成星座对极区进行联合观测.其中,上行粒子源区附近的就位探测是电离层-热层耦合机制研究的重点,也是电离层/热层星轨道设计的关键.根据相关空间探测计划和卫星观测结果,通过比较圆轨道和椭圆轨道两种方案,确定电离层/热层星采用椭圆轨道.

磁层-电离层-热层是等离子体与中性气体共存、彼此紧密耦合的复杂系统,是太阳剧烈活动引起灾害性空间天气的主要发生区域,对于人类航天活动的安全及导航/通信系统的正常运行有着重要影响.对该区域的探测研究蕴涵重大的科学意义并具有重要的应用前景.本文总结了国际和国内开展的磁层、电离层、热层的空间探测研究,分析了已经实施的研究发现的一些关键科学问题,对未来研究磁层-电离层-热层耦合的卫星探测计划提出了初步设想.

Currently,with the influence of long term exploitation of oil,gas,groundwater and brine resources,the increase of surface load and the compaction of recent sediments,ground subsidence has become one of the main geological hazards of the modern Yellow River Delta,China.Wetlands are broadly distributed,and most areas are covered by vegetation in this region,which make monitoring more difficultly.This article introduces monitoring of ground subsidence in the modern Yellow River Delta area using PSInSAR technique.To carry out experiment 10 ERS1/2 images during June 1992 and August 1995 were collected,and with Hooper’s PSInSAR algorithm model,more than 80 000 PS points were selected.3.0 was chosen as the threshold of standard deviation to screen the PS points,and PS points were drop out which were affected by noise.PS points that in Dongying airport were chosen as reference points to correct the results,then the mean subsided velocity map and the deformation quantity in time series were derived.Ground subsidence phenomenon are widely distributed in the modern Yellow River Delta area.The mean subsided velocity is about 4.4 mm/a in most coastal area,mean subsided velocity of Shengli Oil Production Plant and its surrounding areas is 10.1mm/a.In the west city district of Dongying the value is 7.1 mm/a and in the east city district of Dongying the value is 7.4 mm/a.Subsided velocity map,the residential map and oilfield distribution map were overlapped to analyze the relationship between them.The results show that subsided velocity of the modern Yellow River Delta has high correlation with exploitation of oil,the increase of surface load and natural compaction of sediments.The accuracy of PSInSAR technique was verified by traditional Leveling data.Four leveling points were taken near PS points.Although the monitoring time interval and location of Leveling points was not in full accord match with PS points,the monitoring results gotten by PSInSAR technique was consistent with the leveling results.The subsided quantity curve of one leveling points which were 80 m distant from the nearest PS point and monitoring during the same time interval is very similar with the PS point’s subsided quantity curve,and the mean square error between them is 0.88 mm,so the mean square error gotten by PSInSAR technique was within the bounds of millimeter level.The results show that PSInSAR technique based on small data set can be used to monitor ground subsidence either the area is vegetation covered or wetland area,if only it have stable scatters.

The feasibility of attaining short pulse duration heavy ion beam with a scale of nanosecond pulse length was studied in the Heavy Ion Research Facility in Lanzhou—Cooling Storage Ring(HIRFL-CSR),such heavy ion beam can be produced by non-adiabatic compression,and it is implemented by a fast rotation in the longitudinal phase space.In this paper,the bunch compression beam dynamics of 238U72+ which the energy is 250 MeV/u,initial bunch pulse duration is 200 ns,and the initial momentum spread is 5×10-4 was computed with K-V envelope model,and the possible beam parameters are presented during bunch compression.The short 238U72+ bunch of 16 ns is got which can satisfy with the research of high energy density physics.

The scheme of longitudinal bunch compression cavity for the Cooling Storage Ring(CSR)is an important issue.Plasma physics experiments require high density heavy ion beam and short pulsed bunch,which can be produced by non-adiabatic compression of bunch implemented by a fast compression with 90° rotation in the longitudinal phase space.The phase space rotation in fast compression is initiated by a fast jump of the RF-voltage amplitude.For this purpose,the CSR longitudinal bunch compression cavity,loaded with FINEMET-FT-1M is studied and simulated with MAFIA code.In this paper,the CSR longitudinal bunch compression cavity is simulated and the initial bunch length of 238U72+ with 250 MeV/u will be compressed from 200 ns to 50 ns.The construction and RF properties of the CSR longitudinal bunch compression cavity are simulated and calculated also with MAFIA code.The operation frequency of the cavity is 1.15 MHz with peak voltage of 80 kV,and the cavity can be used to compress heavy ions in the CSR.

In order to obtain optimization threshold for the centroid algorithm,several kinds of influencing factors,such as signal-to-noise ratio,discrete gathering of star point and so on,are studied.Based on theoretical computation,a function is established to depict the relationship between the luminosity of star spot and the threshold with optimization centroid accuracy.Then,by combining the function with the simulation results of discrete gathering of star spot,a method of obtaining the optimization threshold based on luminosity of star spot is proposed.Based on the relationship between optimization threshold and luminosity of the spot,a curve model is established,and the optimization threshold is educed by interpolation.The threshold estimation accuracy of the method is shown,and the centroid accuracy is also compared with those of various thresholding algorithms.The experimental results indicate that the luminosity estimation error of the optimization threshold is less than 3 under different SNR conditions of the camera system,and the centroid locating accuracy by proposed method has raised by 1/100~1/10 pixel level as compared with those of other methods,which can satisfy the requirement of dynamic threshold optimization of centroid algorithm.

The tasks scheduling algorithm is the key factor to the performance of the embedded parallel computing system. Heuristic scheduling algorithm is a simple multi-task scheduling algorithm with good performance in embedded distributed system. The present scheduling algorithms are mostly based on task duplication,and the dependence between the predecessor tasks and successor tasks is not well taken into account. In this paper,a new scheduling algorithm based on Dependent Tasks Optimization(DTO) is presented. For the algorithm,the scheduling length and the number of the processing units are decreased by analyzing the load and the idle time of the processor. The result of algorithm analysis shows that the performance of the DTO algorithm is better than other scheduling algorithms,it is a better choice for tasks scheduling in the embedded parallel computing systems.