HTPB的老化特性

讨论了HTPB的老化问题.研究了未加防老剂储存十年的R-45MHTPB的固化性能,进行了化学分析,测定了力学性能,作了溶胀试验.结果表明HTPB性能变坏主要是由于双键交联而不是链的断裂.此外,红外分光分析证明,用IPDI使已老化的HTPB预聚物交联固化时,在胶片表面生成透明玻璃状的、脆的薄膜,这是预聚物中的已氧化链段向界面迁移的结果.     

中燃速丁羟推进剂的湿老化研究

研究了中燃速丁羟推进剂的湿老化行为，结果表明，湿度对丁羟推进剂力学性能的影响是显著的，并且力学性能的降低与绝对湿含量相关，推进剂短时间吸湿，可采取烘干处理的方法使力学性能得到恢复。     

硝胺对低燃速丁羟推进剂能量与燃速的影响

从推进剂的能量特性和燃烧性能的角度探索了硝胺（RDX、HMX）在低燃速丁羟推进剂应用的可能性，结果表明：保持固体含量和铝粉含量恒定时，在推进剂中加入一定量的硝胺部分取代AP，可以提高低燃速丁羟推进 理论比冲和显著降低推进剂的燃速压强指数，但加入RDX、HMX降低丁羟推进剂燃速的幅度非常小。     

复合固体丁羟推进剂药柱表面防湿涂层研制

介绍了一种丁羟推进剂药柱表面防湿保护涂层,它可以涂敷在药柱表面形成一层薄膜,其透湿系数小于3.0×10~(-13)g·cm/(m~2·s·Pa),能有效阻止湿气扩散到推进剂内部,这种保护涂层有效地降低了湿气对推进剂性能的影响,延缓推进剂的老化,而对推进剂点火性能无明显影响。     

含球形铝粉丁羟固体推进剂性能综述

对含球形铝粉丁羟固体推进剂的主要性能进行了简要的综述，涉及的主要性能有能量特性，燃烧特性、力学性能和工艺性能。     

丁羟推进剂老化性能研究——几种防老剂对丁羟推进剂老化性能的影响

本文采用高温加速老化的试验方法研究了老化对推进剂的力学性能、邵氏硬度、相对交联密度、燃速、失重百分数的影响,并以 DSC 曲线的出峰温度作为评定参考.同时,通过电镜技术观察推进剂表面及其拉伸断裂面氧化剂 AP 的分解行为.实验结果表明,防老剂H、α-萘胺和二苯胺这三种防老剂对丁羟推进剂的防老化效果基本相同,但在较高温度下,防老剂 H 稍优于α-萘胺和二苯胺.     

HTPB贮存老化性能

测试和分析了常温条件下长期贮存丁羟胶的相对分子质量（Mr^-)、羟值（OH）和粘度（ηa）数据，研究了贮存下羟胶对推进剂性能的影响。结果表明：贮存丁羟胶的Mr^-，OH和ηa变化不显著，用它制成推进剂的性能仍保持原来水平。     

硝胺（RDX）低燃速丁羟平台推进剂研究

介绍了压强指数n<0.05(4.9～14MPa下)的硝胺低燃速丁羟平台推进剂,以及该推进剂的力学、工艺、安全性能,并简单地分析了产生平台的机理。     

恢复吸湿丁羟推进剂试件性能的研究

阐述了环境湿度对高、中、低燃速丁羟推进剂试件力学性能和药条燃速测结果的影响及其规律；给出了恢复吸湿试件性能的处理方法。     

固化剂TMXDI在丁羟推进剂中的应用

为进一步提升丁羟推进剂的各项性能,加快丁羟推进剂原材料的低毒化进程,开展了低毒固化剂四甲基苯二亚甲基二异氰酸酯(TMXDI)在丁羟推进剂中的应用研究。通过改进混合工艺及新型固化催化剂的组合应用,解决了低毒固化剂TMXDI在应用过程中出现的工艺性能差、固化温度偏高等技术难题。并初步探索了以TMXDI为固化剂的推进剂的力学、老化、燃烧等性能。研究表明,以TMXDI为固化剂的推进剂力学性能良好,其常温抗拉强度为1.03 MPa时,其最大伸长率可达60%,另外以TMXDI为固化剂的推进剂相比以TDI为固化剂的推进剂还具有更好的工艺性能和老化性能,丁羟推进剂性能得到提升。     

固体发动机O形橡胶圈密封性能试验研究

分析了O形橡胶圈自然贮存、热空气加速老化、相容性及全尺寸发动机密封结构自然贮存等一系列单项试验结果,得到了O形橡胶圈在压缩状态下的密封贮存性能及其使用期,这些结果可供发动机设计使用.     

初始气孔率热老化试验研究与应用：预测双基推进剂储存寿命的一种新方法

通过对双基推进剂药柱进行初始气孔率热老化试验研究。探讨了用累积损伤理论和粘弹性分析方法来预测药柱储存寿命的理论基础和应用价值，提出了一种准确，经济，方便的预测药柱储存寿命的新方法。     

方坯药预测寿命与发动机推进剂药柱实际寿命差异研究

从固化条件、贮存条件、应力状态条件和预测方法4个方面,分析了方坯药预测寿命与发动机推进剂药柱实际寿命存在差异的原因。针对以上原因提出了用修正因子、受力状态模拟试验和老化动力学研究等方法来减少这种差异的技术途径。以提高推进剂寿命预测的准确性。     

Peculiarities of the formation of a thin current sheet in the Earth’s magnetosphere

We investigate the process of the self-consistent formation of a thin current sheet with a thickness close to the ion Larmor gyroradius in the presence of decreasing magnetic field’s normal component B_n. This behavior is typical of the current sheet of the Earth’s magnetospheric tail during geomagnetic substorms. It has been shown that, in a numerical model of the current sheet, based on the particle-in-cell method, the appearance of self-consistent electric field component E_y in the current sheet vicinity can lead to its significant thinning and, eventually, to the formation of a multiscale configuration with a thin current sheet (TCS) in the central region supported by transient particles. The structure of the resulting equilibrium is determined by the initial parameters of the model and by the particle dynamics during the sheet thinning. Under certain conditions, the particle drift in the crossed electric and magnetic fields leads to a significant portion of ions becoming trapped near the neutral sheet and, in this way, to the formation of a wider configuration with an embedded thin current sheet. The population of trapped particles produces diamagnetic negative currents that manifest in the form of negative wings at the periphery of the sheet. Correspondingly, in the direction perpendicular to the sheet, a nonmonotonic coordinate dependence of the magnetic field appears. The mechanisms of the evolution of the current sheet in the Earth’s magnetotail and the formation of a multiscale structure are discussed.     

NEPE推进剂/衬层粘接界面XPS表征

运用XPS分析手段表征了NEPE推进剂/衬层粘接界面的化学组成和老化历程,通过研究界面区的化学组成及分布,得出了界面区各位置及老化前后主要组分的变化;探讨了界面老化过程中元素结合能变化与老化失效的关系,认为界面区域中结合能是286～287 eV的羟基和结合能是401～402 eV的N活性基团的含量降低,以及硝基的分解是粘接界面失效的主要原因.     

NEPE推进剂“两段式”老化的动力学研究

NEPE推进剂老化表现为"两段式",即稳定剂完全消耗前后(分别对应Ⅰ阶段和Ⅱ阶段),推进剂力学性能出现显著差异.文中借鉴双基系推进剂和NEPE推进剂老化研究结果,在进一步分析"两段式"老化特性的基础上,探讨了提高NEPE推进剂贮存寿命的技术途径,计算了"两段式"老化过程的动力学参数,并比较了温度对两阶段主要反应的影响.结果表明,Ⅰ阶段稳定剂消耗反应和Ⅱ阶段推进剂聚合物基体降解反应的表观活化能分别为86.18 kJ/mol和166.35 kJ/mol,常温25 ℃时两阶段的老化速率分别为1.30×10~(-4) d~(-1)和2.75×10~(-6) d~(-1),温度对两个老化阶段都有很大影响,但老化第Ⅱ阶段受温度的影响远大于第Ⅰ阶段.     

发动机药柱和推进剂方坯老化性能相关性研究

通过长期贮存的CTPB推进剂方坯性能变化和发动机中推进剂药柱性能变化比较,研究了发动机药柱和推进剂方坯老化性能的相关性,发现发动机中不同位置的推进剂性能的变化有明显差异,内层推进剂“变软”的速率比外层慢得多。当外层推进剂强度降低较大时,内层推进剂仍有较高的保持率,几乎和推进剂初始性能相同,并且强度由内向外逐渐变化。因此。单用推进剂方坯的老化性能难于推断发动机药柱的寿命,并对这一现象对发动机寿命的影响进行了讨论。     

Tearing mode in thin current sheets of the Earth’s magnetosphere: A scenario of transition to unstable state

The results of numerical modeling of thinning process in the Earth’s magnetotail current sheet are compared with the model of an anisotropic current sheet in collisionless space plasma. Stability of the current sheet during its evolution is investigated. In the evolution one can distinguish three basic stages: 1) transformation of the initial two-dimensional “isotropic” equilibrium that is well described within the MHD-approximation into a relatively thin current structure; 2) further kinetic evolution, as a result of which the virtually one-dimensional, extremely thin current sheet is formed; 3) relaxation of the system into a new equilibrium that can be stable or unstable. A substorm scenario of transformation of the magnetospheric tail and its transition into the unstable state is suggested. The spontaneously appearing tearing disturbance favors a current sheet disruption. It is shown that the estimate of a tearing mode wavelength, obtained from the model, is in accordance with experimental observations during the explosive phase of substorms.     

Turbulence in the Plasma Sheet during Substorms: A Case Study for Three Events Observed by the INTERBALL Tail Probe

Variations of turbulence properties of the plasma sheet during geomagnetic substorms are investigated using observations of the INTERBALL Tail Probe satellite. The periods are chosen when the satellite was inside the plasma sheet. Fluctuations of the plasma bulk velocity across the plasma sheet are studied for the growth, expansion, and recovery phases of geomagnetic substorms on October 14, 1997; October 30, 1997; and December 16, 1998. It was demonstrated that the level of turbulence increases considerably after the onset of the substorm expansion phase and slowly decreases nearly to the presubstorm level later. The correlation times of plasma fluctuations in the Z-direction are estimated, and diffusion coefficients in the Z-direction are calculated.