频率稳定度与守时钟组配置关系研究CSCD

通过对中小型守时实验室对时间尺度稳定度的需求分析,以目前主流守时钟5071A为例,利用国际权度局公布的原子钟数据,研究不同钟组配置与时间尺度稳定度的关系,为中小时间实验室守时钟组的优化配置提供参考依据;权重确定是原子时算法的关键之一,通过对不同数量、不同取权规则的原子时计算结果进行统计分析与比较,提出中小时间实验室原子时尺度算法中的取权原则。     

HORACE: A compact cold atom clock for Galileo

HORACE (HOrloge à Refroidissement d’Atomes en Cellule = clock based on atoms cooled from vapour cell) is a compact cold caesium atom clock developed in SYRTE at Paris Observatory. This clock can operate both on ground and in microgravity environment. Design of HORACE is based on isotropic light cooling, allowing performing the whole clock sequence (cooling, atomic preparation, Ramsey interrogation and detection) at the same place. Compared to more conventional cold atom clocks such as atomic fountains, the use of isotropic light cooling simplifies both the optical part of the setup and the detection sequence, and leads to a drastic size reduction of the physics package. Very good short-term performances have been demonstrated at SYRTE since relative frequency instability of 2.2 × 10⁻¹³ τ^−1/2 has been obtained. Optimization of the long term stability is still under progress and current results show relative frequency instability around 3 × 10⁻¹⁵ in 10⁴ s of integration. With these performances, HORACE appears as a good candidate both for Galileo’s ground segment clock and for onboard Galileo clock.     

高阶矩谱分析与空间等离子体非线性相互作用识别

利用高阶矩统计分析方法对ＡＵＲＥＯＬ－３卫星观测数据进行分析处理，所涉及的信号分别为ＥＬＦ频率范围内的电场扰动Ｅｈ（ｔ）和等离子体密度波动δＮｅ／ｎｅ（ｔ），处理结果表明：利用高阶矩谱分析方法可以很好地识别空间等离了波－粒相互作用过程中的非线性成分     

非金属电热膜材料及工艺分析

本文论述了制作电热膜的工艺过程.对电热膜的材料、烧结工艺及使用寿命进行了试验,获得了有价值的结论.并论述了提高电热膜产品寿命应注意的问题.     

可移动式六极束管型铯原子钟

描述了一种可移动式铯原子钟的设计和性能。该装置可断续或连续运行,结构独特、潜力较大,在一定使用环境下,主要技术指标达到了国外商品铯钟相应的先进水平。     

疲劳学的研究进展

随机疲劳、混沌疲劳及复合材料疲劳寿命估算属疲劳学研究的三个重要前沿。给出了疲劳损伤的动态概率分布；对混沌疲劳进行了初步探索；且给出了用于复合材料疲劳寿命估算的损伤演化方程。     

随机疲劳累积损伤可靠性分析模型

将疲劳损伤累积过程看作是能量耗散的不可逆过程，从随机过程的角度，研究了各类随机损伤累积法则均应满足的若干必要条件，对目前已有的一些概率型疲劳损伤累积法则的统计相容性进行了较为系统的理论分析，建立了一类不依赖于疲劳寿命具体分布形式的随机疲劳累积损伤可靠性分析模型。     

存在剥离条件下颗粒物沉积过程的数值研究和实验验证

为了更加准确地模拟涡轮叶片表面颗粒物沉积的增长过程和分布状况,研究颗粒物沉积过程中粘附、剥离直至稳定平衡的规律,在经改进的颗粒粘附模型基础上考虑两种剥离形式,利用Fluent的User Defined Function (UDF)功能和网格重构技术,最终实现了熔融石蜡颗粒于带有气膜冷却的平板上沉积动态增长的过程。通过与相同条件下所得实验结果的对比,验证了所用模型的有效性和合理性。随后研究了是否加入剥离模型、气膜冷却吹风比、气膜孔射流角度等因素对沉积效果的影响。计算结果表明,考虑颗粒的剥离效应将减少颗粒物沉积的总量,尤其是在气膜孔后较短区域内;此外,吹风比的增加将使颗粒不易撞击壁面,已粘附的颗粒也更容易剥离从而降低沉积的厚度和质量;射流角度不断增大则使气膜覆盖效果变差,壁面温度升高,颗粒更易达到熔融状态沉积下来。研究发现该数值方法有助于更加精确地仿真沉积增长的过程,证实了吹风比和射流角度对沉积的分布和厚度有很大影响。当射流角度处于35°～40°时,可在一定程度上减少沉积。     

Analysis and control of the compaction force in the composite prepreg tape winding process for rocket motor nozzles

In the process of composite prepreg tape winding, the compaction force could influence the quality of winding products. According to the analysis and experiments, during the winding process of a rocket motor nozzle aft exit cone with a winding angle, there would be an error between the deposition speed of tape layers and the feeding speed of the compaction roller, which could influence the compaction force. Both a lack of compaction and overcompaction related to the feed-ing of the compaction roller could result in defects of winding nozzles. Thus, a flexible winding sys-tem has been developed for rocket motor nozzle winding. In the system, feeding of the compaction roller could be adjusted in real time to achieve an invariable compaction force. According to exper-iments, the force deformation model of the winding tape is a time-varying system. Thus, a forgetting factor recursive least square based parameter estimation proportional-integral-differential (PID) controller has been developed, which could estimate the time-varying parameter and control the compaction force by adjusting the feeding of the compaction roller during the winding process. According to the experimental results, a winding nozzle with fewer voids and a smooth surface could be wounded by the invariable compaction force in the flexible winding system.     

玻璃纤维复合材料的原子氧剥蚀效应试验研究

对两种玻璃纤维复合材料开展了原子氧效应的地面模拟试验研究。总结了试验前后试样质量及表面形貌的变化规律，计算得到了材料的剥蚀率。试验结果表明，随着原子氧累积通量的增大，玻璃纤维复合材料的质量和体积损失减慢。经分析认为，在原子氧与复合材料的作用过程中，树脂优先被剥蚀，而将纤维暴露在外，由于玻璃纤维对底层树脂基体的遮挡作用，导致在原子氧效应试验后期，玻璃纤维复合材料的剥蚀速度减缓。