2018 Vol. 38, No. 4

Display Method:
TESS任务成功发射
2018, 38(4): 429-429.
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ESA第4个中级科学任务聚焦系外行星性质研究
2018, 38(4): 429-429.
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俄罗斯重启Ionosond-2025电离层探测项目
2018, 38(4): 430-430.
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SDO揭示太阳磁笼阻止太阳喷发机制
2018, 38(4): 430-430.
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NASA成功发射Insight火星探测器
2018, 38(4): 430-430.
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ESA和NASA签署火星采样返回任务研究意向书
2018, 38(4): 431-431.
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ESA成功发射Sentinel-3B任务
2018, 38(4): 431-431.
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Swarm发现地球第二磁场
2018, 38(4): 431-431.
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美国科学家发现几十年来全球海平面处于加速上升状态
2018, 38(4): 431-431.
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ESA成功试验世界首个吸气式电推进器
2018, 38(4): 432-432.
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ISS外部将安装Bartolomeo商用研究平台
2018, 38(4): 432-432.
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美国发布《NASA战略规划2018》
2018, 38(4): 433-434.
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LPI更新月球探索核心科学概念
2018, 38(4): 435-436.
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美国宇航局推举出新局长
2018, 38(4): 436-436.
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Relationship Between Solar Proton Events and the Associated Solar Flares
LE Guiming, WANG Hongyan, BAI Tienan
2018, 38(4): 437-443. doi: 10.11728/cjss2018.04.437
Abstract(1787) PDF 454KB(1773)
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The Correlation Coefficients (CC) between the time integral of solar Soft X-Ray (SXR) flux and the intensities of Solar Proton Events (SPE) in 0°W-39°W, 40°W-70°W and 71°W-90°W longitudinal areas have been calculated. The results show that the CC has its largest value. The property of CC is consistent with the concept that the largest flux of flare-accelerated particles can only be observed in the longitudinal area well magnetic connected with the observer. The results suggest that solar flares contribute to the production of SPE, namely that E ≥ 10MeV protons may be accelerated by the concurrent flares at the early phases of SPE.
Cold-dense Plasma Sheet and Its Impact on the Spatial Distributions of the Magnetotail Plasma Sheet ormalsize
BAI Shichen, SHI Quanqi, TIAN Anmin, ZHANG Shuai
2018, 38(4): 444-451. doi: 10.11728/cjss2018.04.444
Abstract(1647) PDF 2121KB(1642)
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Plasma sheet plays an important role in the coupling of solar wind and Earth magnetosphere, and the Cold-Dense Plasma Sheet (CDPS) is an important evidence of solar wind entry during the geomagnetic quiet time. However, there are handful statistical analyses using in situ observations to investigate the 2D profile of ion number density, temperature of plasma sheet and the CDPS occurrence rate in the xy plane of GSM coordinate. The Geotail data from 1996 to 2016 are used to fill that blank. The 2D profile of ion density, temperature of plasma sheet and the CDPS occurrence rate are plotted. A dawn-dusk asymmetry is seen in the 2D profile of ion density and in the cold-dense plasma sheet occurrence, but not seen in the 2D profile of ion temperature. The dawn-dusk asymmetry of ion density is more clear during the geomagnetic quiet time than that during the geomagnetic active time. Furthermore, the possible affect caused by the CDPS on the 2D profile of ion number density and temperature of the plasma sheet are investigated.
Numerical Modeling of Ion Contributions in Ionospheric Sporadic-E Layerormalsize
ZHANG Yabin, WU Jian, XU Zhengwen, XU Bin, XU Tong, LIU Yao, HU Yanli, WANG Zhange
2018, 38(4): 452-459. doi: 10.11728/cjss2018.04.452
Abstract(1869) PDF 2714KB(1718)
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The ionospheric kinetic numerical model is expressed as the solution to the temporal evolution of the electron density profile. The ion continuity and the momentum equations, the solar ionization, star ionization, coronal ionization, interstellar background ionization and meteor ion flow are all considered. The main kinetic process and photochemical process of Es layer are analyzed synthetically. The effects of neutral component collision, electric field, metal ion and molecular ion on the ion distribution are also included. In the paper, a one-dimensional time-dependent model of the ionospheric Es has been developed on the basis of the wind shear theory. The ion production rate and the distribution of the vertical ion velocity in height and time are simulated by the model. The variations of ion density profile in 24 hours are also obtained. According to the observation results of winds by coherent scattering radar in Kunming station, the time and space dependent of electron density of Es (Ne) is acquired by the model. Then the f0Es are given by the conversion of Ne, and the retrieval results are in good agreement with the contemporaneous ionosonde data in Kunming.
Application of ERA5 Reanalysis to the Construction of Initial Conditions for WACCM Simulations
WANG Yegui, JING Wenqi, CUI Yuanyuan, CAI Qifa, LAN Weiren, FANG Hanxian, WENG Libin, NIU Jun
2018, 38(4): 460-468. doi: 10.11728/cjss2018.04.460
Abstract(1312) PDF 3465KB(2364)
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This study uses ECMWF fifth-generation reanalysis, ERA5, which extends to the mesopause, to construct the Initial Conditions (IC) for WACCM (Whole Atmosphere Community Climate Model) simulations. Because the biases between ERA5 and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperature data are within ±5 K below the lower mesosphere, ERA5 reanalysis is used to construct IC in the lower atmosphere. Four experiments are performed to simulate a Stratospheric Sudden Warming (SSW) event from 5 to 15 February 2016. The simulation using the WACCM default climatic IC cannot represent the sharp meteorological variation during SSW. In contrast, the 0~4 d forecast results driven by ERA5-constructed IC is consistent with ERA5 reanalysis below the middle mesosphere. Comparing with WACCM climatology ICs scheme, the ICs constructing method based on ERA5 reanalysis can obtain 67%, 40%, 22%, 4% and 6% reduction of temperature forecast RMSE at 10 hPa, 1 hPa, 0.1 hPa, 0.01 hPa and 0.001 hPa respectively. However, such improvement is not shown in the lower thermosphere.
Numerical Simulation of Stratospheric Gravity Waves Induced by a Rainstorm
SUN Rui, YAO Zhigang, HAN Zhigang, ZHAO Zengliang, CUI Xindong, YAN Wei
2018, 38(4): 469-481. doi: 10.11728/cjss2018.04.469
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In order to analyze the characteristics of the deep convection-induced stratospheric gravity waves in Chinese continental region, a stratospheric gravity wave process, which is observed by the satellite Aqua/AIRS and accompanied with the heavy rainstorm process on July 25th, 2011 in Rushan, is simulated using the mesoscale numerical WRF (Weather Research and Forcasting) model. The analysis of the vertical velocity field and the temperature disturbance field of the mode output show that the structure of the torrential wave in the stratosphere is mainly concentrated in the east of the precipitation cloud system, and the horizontal influence range is more than 1000km. With the increase of the height, the structure of the torrential wave tends to close, and the wave energy is also significantly enhanced. The results of power spectrum analysis based on Fast Fourier Transform (FFT) show that the stratospheric gravity wave induced by the storm at 35km has the horizontal wavelength of about 1000km and the vertical wavelength of 5~10km. Finally, the parameterized forcing in gravity wave uploading process is quantifiably reflected by analyzing the vertical transport of momentum flux reflects.
Characteristics of Wind and Planetary Waves Based on FPI over Kelan of Chinaormalsize
ZHANG Yiyao, SHENG Zheng, SHI Hanqing, JIANG Yu, YANG Pinglü, CAO Yu
2018, 38(4): 482-491. doi: 10.11728/cjss2018.04.482
Abstract(1596) PDF 5057KB(1655)
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The horizontal wind data observed by Fabry-Perot Interferometer (FPI) over Kelan, China, has been used to investigate the characteristics of wind and planetary waves at altitudes of 87, 97 and 250km. Firstly, the midnight winds have been compared with those from HWM07. The results are as follows. At 87 and 97km, the AO (Annual Oscillation) and SAO (Semiannual Oscillation) phases of zonal wind of FPI tend to consist with those from HWM07, while the phases of FPI meridional wind lag behind. Both the zonal and meridional FPI amplitudes are smaller. It shows large discrepancies between FPI and HWM07 winds, which reveals that the improvement of HWM07 model needs to further consider the influence of solar activity and interplanetary magnetic field. Secondly, the Lomb-Scargle analysis and the least squares harmonic fitting method have been used to derive the amplitudes of planetary waves at the three altitudes. At 87 and 97km, the 16-day waves are prominent at autumn, winter and spring during 2013-2014, while the 6.5-day waves tend to dominant spring and autumn. Both of the two planetary waves have weak amplitudes around mesopause. The amplitudes are stronger in meridional wind than zonal at 250km. Three typical planetary wave period bands of meridional wind show that the strongest amplitudes persist from May to October. This is consist with the results of ionospheric f0F2 oscillations.
Abnormal Echoes in Lower Stratosphere Observed by Wuhan MST Radar during a Cold front Event
PAN Zhenhao, ZHOU Xiaoming, CHEN Gang, YAN Chunxiao, CHEN Feilong, WANG Ying
2018, 38(4): 492-501. doi: 10.11728/cjss2018.04.492
Abstract(1978) PDF 3209KB(1682)
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Wuhan Mesosphere-Stratosphere-Troposphere (MST) radar is a radio atmosphere detection radar deployed by the Chinese Meridian Project. As the frequency is in VHF band, the echoes are sensitive in all their aspects. Such echo characteristics are much more obvious in the Upper Troposphere and Lower Stratosphere (UTLS), which provides a practical approach to investigate the atmosphere dynamics. Observations of echo characteristic during a cold front are obtained by Wuhan MST radar in mid-latitude in April 2016. The experiment results show that the typical feature of the echo aspect sensitivity is significantly changed compared with that of normal days. Reasons of the echo anomaly are studied by analyzing echo characteristics variations, wind field spatial distributions, turbulence generation mechanisms and Inertia Gravity Waves (IGWs) effects. The result demonstrates that the dissipating (or even breaking) of upward IGWs coming from convection system might feed the long-time persistence of Kelvin-Helmholtz (K-H) instability, which further tilts the horizontal reflection layer and results in the intense turbulence and the echo enhancement.
Neutron Radiation Environment and Resulting Single Event Effects Prediction in Near Spaceormalsize
ZHANG Zhangang, LEI Zhifeng, SHI Qian, YUE Long, HUANG Yun, EN Yunfei
2018, 38(4): 502-507. doi: 10.11728/cjss2018.04.502
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Neutron radiation environment in near space is analyzed by Space Radiation 7.0 toolkit. It is found that neutron flux decreases by several orders as altitude increases, low-energy neutron flux increases sharply at solar maximum condition, neutron flux increases constantly as latitude ascends. The inner reasons are further investigated. Based on the results, a prediction technique of atmospheric-neutron induced Real-Time Soft Error Rate (RTSER) using Monte-Carlo method is proposed. Taking Field Programmable Gate Array (FPGA), critical Integrated Circuit (IC) used in avionics system, as an example, the RTSERs of Single Event Upset (SEU) sensitive modules (including Configurable Memory (CM), Block Random Access Memory (BRAM) and user Flip-Flops (FF)) and Single Event Functional Interrupt (SEFI) sensitive modules (including Power-On-Reset (POR), SelectMAP etc.) are predicted. The results show that SEUs in CM accounted for 77% of the total SEU rate in the FPGA. Both POR and SelectMAP SEFIs accounted for 36% of the total SEFI rate respectively. According to the failure levels of flight system in RTCA DO-254, the FPGA can not be employed in key positions of avionics.
Reconstruction of the Typhoon Center and Wind Speed Distribution Using HF Sky-wave Backscatter Spectrumormalsize
LU Zhuanxia, LI Xue, LI Jining, HUA Caicheng, LÜ Zhe
2018, 38(4): 508-516. doi: 10.11728/cjss2018.04.508
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By analyzing the distribution characteristics of HF sky-wave backscatter clutter spectrum, the three-spectrum filter model is constructed to extract the Bragg line ratio in multi-type spectrum. The extractions are in good agreement with the measurements. Combining the backward difference method, the Typhoon center has been determined effectively on the basis of the correlation analysis of Typhoon center and the Bragg line ratio. The results are basically in line with the data released by the meteorological department. The average absolute error is about 38km. Using the modified empirical model, the maximum wind speed in Typhoon center and the wind speed near Typhoon center are preliminarily investigated. The reversions are basically consistent with the data released by the meteorological department. The results show that HF sky-wave backscatter sounding is of great significance and application value for state monitoring of the sea with wide range and long distance.
Soot Formation in Laminar Diffusion Flame under Microgravityormalsize
YUAN Hongliang, KONG Wenjun
2018, 38(4): 517-523. doi: 10.11728/cjss2018.04.517
Abstract(2011) PDF 2750KB(1695)
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The soot formation in a coflow ethylene/air laminar flame at 1g/0g (normal gravity and zero gravity) has been studied using particular fuel oxidation and PAH mechanism. The nucleation process is regarded as the dimerization of two large PAH, and HACA mechanism is used to describe the surface growth process. The collision of soot and PAH is mainly taken into account for the condensation process in soot surface. The initial nucleation, soot surface growth, condensation and oxidation are simulated with a discrete sectional aerosol model to capture the different size soot with different mass. The calculating results show that the peak temperature of the flame at 0g decrease by 230K, whereas the peak soot volume fraction is nearly twice larger than that of the 1g condition. This paper also studied the distribution of precursors (C2H2 and PAH), nucleation rate, surface growth rate, and condensation rate under microgravity. It is indicated that the condensation is the major process of soot formation in the centerline of flame for both 1g and 0g conditions, and it plays a more important role under microgravity. The average diameter of soot is lager due to long residence time under microgravity.
Structure Design of Multifunctional Supporting Bench in the Microgravity Combustion Science Experimental System ormalsize
SHANG Lan, WANG Baorui, LIU Chuang, KONG Wenjun
2018, 38(4): 524-529. doi: 10.11728/cjss2018.04.524
Abstract(1552) PDF 2540KB(1602)
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The microgravity Combustion Science Rack (CSR) in a manned space station can provide extended duration microgravity environment for combustion study. It thus has significant value for the development of combustion theories and models and the breakthrough of aerospace propulsion technology. In the CSR, the Multifunctional Supporting Bench (MSB) is a crucial structure because it is used to fix a variety of parts and units such as the combustion measuring devices, the combustor and the experimental control modules and so on. The MSB must have enough stiffness and installation space in view of the constraints of size and mass. In this paper, a split-body structure is designed to make the MSB smoothly pass through the hatch. According to the finite element method, structural optimization design as well as modal analysis is employed to satisfy the stiffness requirement without overweight.
Infrared Materials Growth under Microgravity in Spaceormalsize
JIAO Cuiling, WANG Reng, LU Ye, LI Xiangyang
2018, 38(4): 530-538. doi: 10.11728/cjss2018.04.530
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Recent developments of infrared materials growth in space have been reviewed. The growth methods mentioned here includes melt, vapor growth, liquid phase epitaxy and molecular beam epitaxy. The fundamental principles have been presented for materials grown by different methods. A comparison of ground and space growth has been made giving the challenges and advantages respectively. The ZnTe:Cu crystal was grown using the melt method under microgravity conditions on board of TG-Ⅱ spacecraft, and a reference crystal was grown on Earth under gravity conditions. The related experimental results between the space and terrestrial conditions have been compared. Both the current methods of melt and vapor and perspective development by molecular beam epitaxy have been presented for high-performance, large-scale infrared material growth in space. Lastly the future direction is demonstrated for the space-borne growth of infrared material.
Effect of Substrate and Flow Rate on Hydroxyapatite Growthormalsize
DAI Guoliang, LAN Ding, CHEN Jialu
2018, 38(4): 539-545. doi: 10.11728/cjss2018.04.539
Abstract(1086) PDF 8371KB(2873)
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Hydroxyapatite (HAP) has excellent biocompatibility and bioactivity. Synthetic HAP can be widely used as medical and eco-friendly materials. In order to know valuable information of study and development of bone tissue engineering, the influence on HAP crystals growth by the changed of fluid field and the chosen of substrates are studied. The composites materials are used as substrates, which are made of Polydimethylsiloxane (PDMS)/HAP, PDMS/bioglass, and pure bioglass, respectively, and the effect of different substrates on HAP growth are analyzed. The results show that HAP crystals growth rates are different on different substrates when the flow rate is zero. HAP crystals growth rate is highest on PDMS/HAP substrate. However, it is lowest on pure bioglass substrate. Moreover, the influence of different flow rates of HAP growth solution (Simulated Body Fluid, SBF) by a homemade flow rate adjustment apparatus is studied. Three different flow rates, 10ml/min, 15ml/min, and 30ml/min, are used in this study. Under SBF flow conditions, the sizes of HAP crystals increased and the amount of amorphous precipitate decreased.
Numerical Simulation of Flow Velocity and Silver Ion Concentration Distribution in Sterilization Moduleormalsize
LI Peng, TAN Xu, MA Yong, YU Haibin, XIE Wen, LI Leilei
2018, 38(4): 546-552. doi: 10.11728/cjss2018.04.546
Abstract(1954) PDF 2159KB(1689)
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Future manned spacecraft needs to provide a long-term working environment, in which sterile water is the guarantee of life and health. The sterilization module is installed at the end of the water treatment system to release the specified concentration of silver ions to the purified water, playing a role of sterilization and long-term preservation of the water. According to the exchange basin using standard k-ε model standard wall function, the calculating model of flow field and concentration field of silver ions have been set up for the 600mL·min-1 flow condition as the water flows through the wall. The sterilization module electrode alternating exchanges with 30s period, and draws the concentration change. For meeting the actual conditions, the model is solved by iterative method. By analyzing the production rate of silver ion velocity, the highest concentration of silver ions locates at the anode surface near the cathode. Anode-cathode converting repeatedly can effectively reduce the silver ion concentration near the electrode surface. That is, the conversion has transmission effect to the decreasing of silver ion concentration, and can be carried out repeatedly. There is no AgOH precipitation, and then the process parameters can be determined and the engineering design can be guided. Finally, according to the simulation results, the optimization suggest of the sterilization module is given.
Accuracy Analysis of Satellites Velocity with BDS Broadcast Ephemeris Based on Position Observationsormalsize
CHANG Zhiqiao, HU Xiaogong, SHI Xin, LI Jin, MA Yongbo, DONG Wenli, SHAO Jia'ni
2018, 38(4): 553-559. doi: 10.11728/cjss2018.04.553
Abstract(2323) PDF 1141KB(1670)
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Using broadcast ephemeris to calculate the velocity vector of navigation satellites is a necessary condition for GNSS real-time velocity determination. In this paper, the accuracy of velocity vector calculated by Beidou broadcasting ephemeris only with position observations is analyzed, and the calculation formula of velocity vector with Beidou 18-element model is deduced. Based on one year data of 13 Beidou satellites in orbit, the accuracy of velocity vector calculated by broadcasting ephemeris is obtained. The results show that the maximal velocity error calculated by the 18-element model is in the order of 10-4-1. At the same fitting period, the velocity accuracy of GEO and IGSO satellites is higher than that of MEO. By analyzing position residual sequence, the conclusion is drawn that the velocity accuracy computed by broadcast ephemeris is very high because of little position residual with smooth change trend. The analysis and calculation results in this paper verify the effectiveness of fitting BDS broadcast ephemeris only using position observations.
Study on the Survivability of Space Tethers Due to Debris Collisionsormalsize
YU Ziyuan, LI Aijun, YANG Shu, WANG Changqing
2018, 38(4): 560-566. doi: 10.11728/cjss2018.04.560
Abstract(1416) PDF 833KB(4262)
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The structures and dimensional parameters of space tether significantly affect their survivability against space debris collisions in complex space environment. This work addresses the probability analysis for double tethers and tape tethers severed by debris based on tether-debris collision model and Poisson distribution. The influence of debris on the survivability of space tethers is also studied. A double tether is a pair of parallel strings connected at a certain distance, and tape tethers can be treated as a specific type of single tethers with rectangular cross-sections. The probability of single tethers severed by space debris is modeled, and the survivability functions for double tethers and tape tethers are also formulated. Moreover, the survivability of tethers with different structures and dimensional parameters is calculated based on a cumulative debris flux model. The results show that double tethers and tape tethers are of higher survivability compared with single tethers.
Centralized Payload Management System for Dark Matter Particle Explorer Satelliteormalsize
WANG Lianguo, ZHU Yan, SHEN Weihua, LIANG Yaoming, TENG Xuejian, ZHOU Changyi
2018, 38(4): 567-574. doi: 10.11728/cjss2018.04.567
Abstract(1693) PDF 2568KB(1592)
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The Dark Matter Particle Explorer (DAMPE) Satellite consists of 4 detectors. The total number of detector Front End Electronics (FEE) is 28. To satisfy the requirements for supporting large numbers of FEEs and complicated interface, a centralized management strategy is proposed. Telemetry and telecontrol, scientific data and housekeeping data collection, secondary power supply of all the payloads are realized by payload management system. In addition, the payload management system provides mass data storage and high data rate multiplex function. The scientific data and the housekeeping data can be stored separately by the mass data storage, which based on flash memory. When entering the ground receiving station, the stored data can be retrieved and formatted to CCSDS protocol frame, and then the frame is channel-coded and sent to X-band transmitter. The strategy solved several key technologies such as burst and multi-source scientific data collection and storage, onboard autonomous detection management, and distribution of large capacity and low-noise secondary power supplies. The system has undergone onboard assessment and verification. The results indicate that the control and information architectures are suitable, and the autonomous detection management and health management measures are effective.
Design of Star Simulator with Spatial Background Lightormalsize
XU Da, ZHANG Guoyu, SUN Gaofei
2018, 38(4): 575-582. doi: 10.11728/cjss2018.04.575
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In order to satisfy the high precision calibration requirement of the star sensor's optical signal, a star sensor ground calibration system with spatial background light is proposed. It solves the problem of calibration accuracy of the star sensor's optical signal due to the spatial background light, improves the accuracy of star sensor calibration. The influence of spatial background light on the calibration accuracy of star sensor is analyzed. The scheme of star simulator with spatial background light is given. A set of star simulator optical system which can simulate spatial background light and star point position at the same time is designed. The results show that the system distortion is smaller than 0.1%, MTF is larger than 0.5 with 80lp·mm-1. The system satisfies the high-precision requirements. A set of spatial background light system is designed through the control of the current and the variable iris. The background brightness adjustment is up to 26 times. Finally, a method of correct star point position with aberration compensation is proposed, and the correction model is presented. The star position error and spatial background brightness of the star simulator are tested by using the Leica T6100 theodolite and the illuminometer. The result shows that the spatial background brightness adjustment is up to 26 times and the star position accuracy is better than 10". The star simulator can meet the ground calibration requirement of star sensor.
中国科技创新的两个优势和两个短板——访增强型X射线时变和偏振(eXTP)空间天文台首席科学家张双南
2018, 38(4): 583-583.
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中国科学院复杂航天系统电子信息技术重点实验室
2018, 38(4): 584-585.
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