由溶胶-凝胶法制备的La2NiO4+δ支撑透氧膜

采用配合物溶胶－凝胶法制备了具有透氧性能的类钙钛矿结构La2NiO4 δ材料，XRD实验表明为单一相，讨论了控制溶胶－凝胶过程的条件，成功地制得了均匀澄清的稳定溶胶和稳定凝胶，采用Al2O3多孔陶瓷为支撑体，用上述溶胶制备了支撑致密透氧膜，结果表明在孔径为0．2μm的多孔Al2O3陶瓷片上制备的支撑膜比较理想，膜的厚度约为35um，透氧实验结果表明，该支撑膜比传统方法制备的同种材料无支撑膜有更好的透氧性能，由于膜内部的离子传输过程是制约透氧通量的主要因素之一，而支撑膜的厚度远小于无支撑膜，较薄的膜减少了离子在固相中的传输距离，有助于加快这一传输过程，从而可获得较高的透氧通量。     

Relative ion Fe,C and O abundances in quiet time particle fluxes in the 23 SC

Using ACE and SOHO data the origin of quiet-time low-energy particle fluxes at 1 AU is studied in the 23rd solar cycle. One of the selection criteria of quiet-time periods is to demand that H/He < 10 provided that periods with noticeable contribution of remnants of gradual events have been excluded from consideration. Our results suggest different origin of 0.03–3 MeV/nucleon particles – different seed populations accelerated and different acceleration processes. During the ascending, maximum and descending phases of solar activity quiet-time ions consist of coronal particles accelerated to suprathermal energies in about a half of the quiet periods, the rest of quiet-time fluxes originates from particle acceleration in processes similar to those in small impulsive solar flares rich in Fe. At solar minimum the bulk solar wind particles serve as seed population.     

Modeling PSBL high speed ion beams observed by Cluster and Double Star

On October 8, 2004, the Cluster and Double Star spacecraft crossed the near-Earth (12–19 R_E) magnetotail neutral sheet during the recovery phase of a small, isolated substorm. Although they were separated in distance by ∼7 R_E and in time by ∼30 min, both Cluster and Double Star observed steady, but highly structured Earthward moving >1000 km/s high speed H⁺ beams in the PSBL. This paper utilizes a global magnetohydrodynamic (MHD) simulation driven by Wind spacecraft solar wind input to model the large-scale structure of the PSBL and large-scale kinetic (LSK) particle tracing calculations to investigate the similarities and differences in the properties of the observed beams. This study finds that the large-scale shape of the PSBL is determined by the MHD configuration. On smaller scales, the LSK calculations, in good qualitative agreement with both Cluster and Double Star observations, demonstrated that the PSBL is highly structured in both time and space, on time intervals of less than 2 min, and spatial distances of the order of 0.2–0.5 R_E. This picture of the PSBL is different from the ordered and structured region previously reported in observations.     

空间材料Kapton的真空紫外与 原子氧复合效应研究

对空间常用聚合物材料Kapton开展了真空紫外辐射及其与原子氧复合效应的地面模拟试验研究,总结了试验前后试样外观、质量、表面形貌、光学参数和表面成分的变化规律,并对反应机理作了初步的分析.结果表明:在原子氧的作用下,Kapton的剥蚀主要是碳氮等元素的氧化所致.而在真空紫外辐射的作用下,Kapton表面会交联形成大分子,从而提高了试样的抗原子氧剥蚀性能.但是,随着原子氧累积通量的增大,这层大分子会逐渐被剥蚀掉,而真空紫外辐射,对Kapton的原子氧效应试验结果没有影响.      

氢氧发动机真空羽流干扰试验研究

为了研究航天器发动机多股羽流产生的羽流干扰对流场结构及参数的影响,在北京航空航天大学真空羽流效应试验系统（PES）中,采用总压皮托管阵列对60 N氢氧模拟发动机单机羽流和双机干扰羽流的压力场进行了测量。试验结果表明:单机羽流流场压力随着轴向距离的增大而迅速降低;受到钟形喷管产生的压缩波束影响,同一轴向距离上的压力最大值逐渐偏离喷管轴线;双机羽流干扰发生于两股发动机羽流主流之间的区域,干扰流的作用范围和强度随着轴向距离的增大而增大,干扰流压力最高可以达到单机羽流相同位置处压力的5倍以上;受到干扰流压缩波束边界的影响,同一轴向距离上的压力最大值逐渐偏离双发动机对称面。      

三床机载制氧系统性能仿真及影响因素分析

建立了三床机载分子筛制氧系统的数学模型,对系统性能进行仿真.仿真结果与实验值进行了对比,两者吻合较好,验证了模型和求解的正确性.在此基础上,对不同飞行高度和工作条件下系统的性能进行仿真预测,研究了产品气流量、吸附压力、冲洗定径孔大小和循环时间对系统工作性能的影响,为三床机载分子筛制氧系统的设计和优化提供了依据.      

热循环对原子氧与树脂基复合材料 交互作用的影响

文章选取M40/DFA-1和M40/AG-80两种碳纤维增强树脂基复合材料,进行了热循环对原子氧与这两种材料交互作用影响的研究。原子氧反应率的计算和层间剪切性能测试的结果表明,一定温度区间一定次数的热循环使得材料与原子氧交互作用减弱。该研究应用X射线光电子能谱仪（XPS）和扫描电子显微镜（SEM）对样品表面成分和形貌进行了分析。根据分析结果,初步提出热循环对增强树脂基复合材料自身抗原子氧侵蚀能力的作用机理。     

剪切同轴式喷嘴中心管壁厚对火焰的影响

为了研究剪切同轴式喷嘴中心管壁厚度对火焰的影响,针对LOX/CH4火焰,采用数值方法计算了三种不同喷嘴中心管壁厚的长方体形燃烧室内的燃烧过程,计算表明,对于较大的管壁厚度,在紧贴管壁下游的区域将形成较大的回流区,有利于火焰稳定在喷嘴出口处,还给出了采用相同几何结构燃烧室的LOX/CH4燃烧试验结果,试验也得出了同样的趋势,随着中心管壁厚度的增加,火焰中心明显前移。     

空间原子氧对低地球轨道航天器用粘结剂的腐蚀效应影响

原子氧是低地球轨道(leo)-种重要的空间环境因素,地面模拟试验是用于开展leo航天器备选材料原子氧环境评价的主要手段.利用北京卫星环境研究所的原子氧设备,对牌号为e-32的环氧树脂和牌号为gs414的硅橡胶两种粘结剂进行了评价试验.依据轨道参数与航天器两年的设计寿命,选定试验中原子氧的等效积分通量为1.4×1021atom/cm2.试验结果表明,环氧树脂样品出现了较大的质量损失,而硅橡胶样品的质量损失则相对较小.根据质量损失计算环氧树脂样品的原子氧反应率处于3.2×10-24～3.8×10-24cm3/atom之间.试验后的环氧树脂样品表面颜色变浅,硅橡胶样品的表面则呈现了玻璃化.对两种材料都进行了表面形貌分析,试验前后测试结果的对比分析表明原子氧的氧化作用使材料表面发生了较大的变化. abstract： atomic oxygen (ao) is prevalent in low earth orbit (leo). ground-based testing on ao exposure was performed to investigate the effects of atomic oxygen on materials to be used in leo spacecraft. two types of adhesive materials, e-32 epoxy and gs414 silicone, were tested in the atomic oxygen testing facility at beijing institute of spacecraft environment engineering (bisee). the equivalent atomic oxygen fluence in test was approximately 1.4×1021 atom/cm2 as determined based on two years' exposure on leo. significant mass losses of the epoxy adhesive samples were observed after the exposure to atomic oxygen, but relatively small mass changes were found in the silicone samples. the erosion yields of epoxy samples range from 3.2×10-24 cm3/atom to 3.8×10-24 cm3/atom. bleaching by atomic oxygen was found in the epoxy samples. the surface on the silicone sample was glossed after ao exposure. the external appearance of both kinds of materials was analyzed using scanning electron microscope (sem) and x-ray photoelectron spectroscopy (xps). a comparison between unexposed and exposed samples shows noticeable changes on the s     

氧化锌半导体薄膜在原子氧探测中的应用

氧化锌半导体薄膜是用于空间原子氧探测的一种敏感材料。采用脉冲激光沉积方法（PLD）在（001）取向的蓝宝石基底上制备出了高质量的氧化锌薄膜,并在地面原子氧模拟设备中考察了其原子氧敏感特性。结果表明,氧化锌薄膜对原子氧有较好的敏感特性,并且在受热后导电性能可以恢复,满足重复探测的要求。