A new modeling method of solar energetic proton events for ISO specification

Solar energetic protons degrade performance and reliability of spacecraft systems due to single-event effects, total dose effects and displacement damage in electronics components including solar cells. On designing a solar cell panel, a total fluence of solar energetic protons (SEPs) which cause solar cell damage is needed to estimate power loss of the solar cells over mission life. Nowadays a solar panel area of spacecraft is increasing as spacecraft mission life becomes longer (15–18 years). Thus an accurate SEP model is strongly required for the cost-minimum design from the aerospace industry. The SEP model, JPL-91 proposed by Feynman et al., is currently used widely for solar cell designing. However, it is known that the JPL-91 model predicts higher fluences of protons than values actually experienced in space, especially after 7 years on orbit. In addition, the model is based on several assumptions, and also needs Monte-Carlo simulations for calculating fluences. In this study, we propose a new method for modeling SEPs especially focused on solar cell degradation. The newly-proposed method is empirical, which constructs a model based directly upon proton flux measurement data taken by instruments onboard spacecraft. This method has neither assumptions nor dependence on SEP event selection, both of which are needed in JPL-91. The model fluences derived from this method show lower fluences in longer missions compared to JPL-91. This method has been proposed to ISO (International Organization for Standardization) and has been discussed for a new standard SEP model.     

基于线性重力差模型的拦截弹中制导技术

针对机载动能拦截弹的中制导段气动力作用可忽略且存在无法实时精确计算重力偏差等特点，提出了一种基于线性重力差模型的预测制导方法。通过线性模型逼近中制导过程中拦截弹与目标之间的重力偏差，以此为依据调整拦截弹的推力矢量并将重力偏差值消除。在此基础上采用延迟点火的策略使得拦截弹的拦截器助推级更好地修正预测模型与实际情况的偏差，经过仿真验证可以将整个中制导段的脱靶量限制在一个较小数值，从而为末制导段提供良好的初始条件。     

2HDNPPb恒容燃烧能的测定及其在RDX-CMDB推进剂中的应用

利用精密转动弹热量计测定了2-羟基-3,5-二硝基吡啶铅盐(2HDNPPb)的燃烧能ΔcU,其结果为(-7 265.08±3.97)J/g。据此计算的标准摩尔燃烧焓和标准摩尔生成焓分别为(-4 425.81±2.43)kJ/mol和(-870.47±2.76)kJ/mol。利用均匀设计法,研究了2HDNPPb、2-羟基-3,5-二硝基吡啶铜盐(2HDNPCu)和炭黑(CB)在RDX-CMDB推进剂燃烧中的复合催化作用,发现当3种组分的加入量分别为1.0%、0.6%和0.6%时,推进剂在所测压强范围内有最高燃速,并且压强指数较低。     

非异氰酸酯聚氨酯(NIPU)研究进展

非异氰酸酯聚氨酯(NIPU)是由环碳酸酯和胺反应得到的一种新型聚氨酯,其吸水性、耐化学性和抗渗透性能均比传统聚氨酯更优良。简要介绍了NIPU的性能特点及合成原理,综述了NIPU的研究现状及在涂料、胶黏剂、泡沫等材料中的应用,对NIPU的发展作了展望。     

Advances in modeling gradual solar energetic particle events

Solar energetic particles pose one of the most serious hazards to space probes, satellites and astronauts. The most intense and largest solar energetic particle events are closely associated with fast coronal mass ejections able to drive interplanetary shock waves as they propagate through interplanetary space. The simulation of these particle events requires knowledge of how particles and shocks propagate through the interplanetary medium, and how shocks accelerate and inject particles into interplanetary space. Several models have appeared in the literature that attempt to model these energetic particle events. Each model presents its own simplifying assumptions in order to tackle the series of complex phenomena occurring during the development of such events. The accuracy of these models depends upon the approximations used to describe the physical processes involved in the events. We review the current models used to describe gradual solar energetic particle events, their advances and shortcomings, and their possible applications to space weather forecasting.     

Solar Energetic Particle Charge States: An Overview

The ionic charge distributions of solar energetic particles (SEP) as observed in interplanetary space provide fundamental information about the origin of these particles, and the acceleration and propagation processes at the Sun and in interplanetary space. In this paper we review the measurements of ionic charge states of energetic particles in interplanetary space and discuss their implication for our understanding of SEP sources, and acceleration and propagation processes.     

Inner radiation belt source of helium and heavy hydrogen isotopes

Nuclear interactions between inner zone protons and atoms in the upper atmosphere provide the main source of energetic H and He isotopes nuclei in the radiation belt. This paper reports on the specified calculations of these isotope intensities using various inner zone proton intensity models (AP-8 and SAMPEX/PET PSB97), the atmosphere drift-averaged composition and density model MSIS-90, and cross-sections of the interaction processes from the GNASH nuclear model code. To calculate drift-averaged densities and energy losses of secondaries, the particles were tracked in the geomagnetic field (modelled through IGRF-95) by integrating numerically the equation of the motion. The calculations take into account the kinematics of nuclear interactions along the whole trajectory of trapped proton. The comparison with new data obtained from the experiments on board RESURS-04 and MITA satellites and with data from SAMPEX and CRRES satellites taken during different phases of solar activity shows that the upper atmosphere is a sufficient source for inner zone helium and heavy hydrogen isotopes. The calculation results are energy spectra and angular distributions of light nuclear isotopes in the inner radiation belt that may be used to develop helium inner radiation belt model and to evaluate their contribution to SEU (single event upset) rates.     

Monte Carlo calibration of the response of the University of Chicago’s Cosmic Ray Nuclei Experiment (CRNE) on IMP-8 to electrons above 0.5 MeV

Modern instrument-simulation techniques offer the possibility of increasing the scientific yield from archival space datasets. In this paper, we report on a simulation of the electron response of the University of Chicago’s Cosmic Ray Nuclei Experiment (CRNE) instrument on the IMP-8 satellite. IMP-8/CRNE returned data from 1973 to 2006. The CRNE particle telescope was designed to measure the isotopic composition of Galactic cosmic-ray (GCR) nuclei and has also been used in many studies of protons and ions above 10 MeV/nucleon from solar energetic particle (SEP) events. But CRNE also functions as a highly-capable detector for solar electrons above 0.5 MeV, an energy range that has not been extensively studied. Utilization of the CRNE electron data has heretofore been limited by the fact that CRNE was never calibrated for electrons. We have therefore used the GEANT4 Monte Carlo simulation package to model the CRNE response to electrons and (separately) protons for multiple energies and incident angles. The results were used to compute the energy- and angle-dependence of the effective area and the energy-dependence of the geometric factor. The response to protons, which was already well understood, was used to verify the mass model, the simulation settings, and the post-processing software. Our simulation of the IMP-8/CRNE electron response now allows analysis of hundreds of relativistic solar electron events observed by CRNE over the years, including studies of evolution of electron energy spectra with high time resolution. We show examples of these results and briefly discuss potential applications to future scientific investigations.     

Forbush decreases and solar events seen in the 10–20 GeV energy range by the Karlsruhe Muon Telescope

Since 1993, a muon telescope located at Forschungszentrum Karlsruhe (Karlsruhe Muon Telescope) has been recording the flux of single muons mostly originating from primary cosmic-ray protons with dominant energies in the 10–20 GeV range. The data are used to investigate the influence of solar effects on the flux of cosmic rays measured at Earth. Non-periodic events like Forbush decreases and ground level enhancements are detected in the registered muon flux. A selection of recent events will be presented and compared to data from the Jungfraujoch neutron monitor. The data of the Karlsruhe Muon Telescope help to extend the knowledge about Forbush decreases and ground level enhancements to energies beyond the neutron monitor regime.     

聚氨酯预聚体合成反应动力学模型的建立及应用

提出了一种测试聚氨酸预聚体合成中氨酯化反应和支化反应的反应动力学参数的理论模型，并对甲苯二异氰酸酯（TDI）与乙二醇（EG）的预聚反应进行了研究，结果表明：通过^13CNMR测出的支化概率值跟从理论模型中获得的支化概率值基本吻合。