大型工程装备可拓制造模型研究

在大型工程装备快速变批量生产需求环境下,基于可拓协同制造资源概念,提出了装备可拓制造"超网络"链制造模式,研究了可拓制造能力单元的RKCQ流模型,构建了可拓制造"超网络"链的参考模型与组建过程模型,并指出使能技术框架体系,可拓制造"超网络"链模式提出的目的在于为大型工程装备制造系统应对不确定性的需求提供制造能力储备.     

直升机静力试验杠杆加载系统的载荷配重计算方法

介绍了直升机静力试验加载杠杆系统配重计算的必要性，包括杠杆系统重心偏离合力中心而引起的后果以及消除该后果的处理方法。然后介绍了载荷系数法的原理以及在大型静力试验中的应用情况。结果表明，利用载荷系数法进行杠杆配重计算，并在加载合力点进行集中扣重，能够消除杠杆系统重量对试验加载的影响，保证试验加载精度。     

Joint Iterative Decoding for Network-Coding-Based Multisource LDPC-Coded Cooperative MIMO

A network-coding-based multisource LDPC-coded cooperative MIMO scheme is proposed,where multiple sources transmit their messages to the destination with the assistance from a single relay.The relay cooperates with multiple sources simultaneously via network-coding.It avoids the issues of imperfect frequency/timing synchronization and large transmission delay which may be introduced by frequency-division multiple access(FDMA)/code-division multiple access(CDMA)and time-division multiple access(TDMA)manners.The proposed joint″Min-Sum″iterative decoding is effectively carried out in the destination.Such a decoding algorithm agrees with the introduced equivalent joint Tanner graph which can be used to fully characterize LDPC codes employed by the sources and relay.Theoretical analysis and numerical simulation show that the proposed scheme with joint iterative decoding can achieve significant cooperation diversity gain.Furthermore,for the relay,compared with the cascade scheme,the proposed scheme has much lower complexity of LDPC-encoding and is easier to be implemented in the hardware with similar bit error rate(BER)performance.     

新兴媒体影响下的大学生思想状况调查研究

在全球化的文化背景下,公共传媒对传统的思想道德、文化底线产生着强大的冲击,而青年学生又是公共传媒的主要受众群体和组成部分。基于当前形势,针对新兴媒体对大学生思想政治教育所产生的影响开展了相应的调查和研究,提出了新形势下高校大学生思想政治教育的思路。调查结果显示:新兴媒体已经对大学生的学习、生活产生了较大的影响,高校应该开辟多种渠道以适应新兴媒体对高等院校思想政治教育所提出的新要求。     

基于CBI的大学英语拓展课程体系研究

以CBI为基本理论依据,探讨了大学英语拓展课程体系设置的基本思路和框架模块构建。从学生的英语水平和学习需求出发,通过把语言知识和学科知识相结合,使学生完成大学英语拓展阶段课程的学习,促进其语言水平和综合素养的全面提高。     

Enhanced multipath mitigation method based on multi-resolution CNR model and adaptive statistical test strategy for real-time kinematic PPP

This study proposes an enhanced multipath mitigation method based on multi-resolution carrier-to-noise-ratio (CNR) model and adaptive statistical test strategy for real-time kinematic precise point positioning (PPP) applications. The multi-resolution CNR model is established with GPS observation data collected from DOY 152 to 181 of 2019 by 230 globally distributed IGS stations, which used to analyze the relevant factors affecting CNR. Statistical results indicate that the CNR is not only related to the satellite elevation, but also closely related to the receiver types and specific satellite. The maximum difference between different receivers can reach 20 dB for the same satellite at the same elevation. In addition, the performance of the CNR is also obviously different between each satellite, and the maximum difference between different satellites is about 10 dB for the same receiver at the same elevation. Hence, in terms of the method which is based on CNR information for multipath detection and mitigation, the independence of receiver types, satellite and frequency must be considered. With the above analysis, this study developed a multi-resolution CNR model based on different receiver types, different satellites and different elevation firstly. Then, combined with the adaptive statistical test strategy which is based on the difference of CNR between inter-frequency and the difference of CNR between adjacent epochs, the multipath can be detected effectively. For the epoch which affected by multipath, the down-weighted strategy based on CNR is adopted to mitigate the influence of multipath on positioning. Real-time kinematic PPP data are collected to assess the proposed method, and the results demonstrate that the proposed method can detect the multipath effectively, and the detection rate can reach 90.28%. Moreover, after adopting the mitigation strategy, the RMS bias of the east, north and up components are improved about 19.95%, 17.89% and 23.07% compared to the original results, respectively. It is worth noting that this proposed method is also suitable for other GNSS, such as GLONASS and BDS, but the corresponding CNR model must be established simultaneously.     

Attitude stability and periodic attitudes of rigid spacecrafts on the stationary orbits around asteroid 216 Kleopatra

In this work, equilibrium attitude configurations, attitude stability and periodic attitude families are investigated for rigid spacecrafts moving on stationary orbits around asteroid 216 Kleopatra. The polyhedral approach is adopted to formulate the equations of rotational motion. In this dynamical model, six equilibrium attitude configurations with non-zero Euler angles are identified for a spacecraft moving on each stationary orbit. Then the linearized equations of attitude motion at equilibrium attitudes are derived. Based on the linear system, the necessary conditions of stability of equilibrium attitudes are provided, and stability domains on the spacecraft’s characteristic plane are obtained. It is found that the stability domains are distributed in the first and third quadrants of the characteristic plane and the stability domain in the third quadrant is separated into two regions by an unstable belt. Subsequently, we present the linear solution around a stable equilibrium attitude point, indicating that there are three types of elemental periodic attitudes. By means of numerical approaches, three fundamental families of periodic solutions are determined in the full attitude model.     

Experimental comparison between aircraft fuel tank inerting processes using NEA and MIG

Fuel tank inerting technologies are able to reduce the fire risk by injection of inert gas into the ullage or fuel, the former called ullage washing and the latter fuel scrubbing. The Green On-Board Inert Gas Generation System (GOBIGGS) is a novel technology based on flameless catalytic combustion, and owning to its simple structure and high inerting efficiency, it has received a lot of attentions. The inert gas in the GOBIGGS is mainly comprised of CO₂, N₂, and O₂ (hereinafter, Mixed Inert Gas (MIG)), while that in the On-Board Inert Gas Generation System (OBIGGS), which is one of the most widely used fuel tank inerting technologies, is Nitrogen-Enriched Air (NEA). The solubility of CO₂ is nearly 20 times higher than that of N₂ in jet fuels, so the inerting capability and performance are definitely disparate if the inert gas is selected as NEA or MIG. An inerting test bench was constructed to compare the inerting capabilities between NEA and MIG. Experimental results reveal that, if ullage washing is adopted, the variations of oxygen concentrations on the ullage and in the fuel are nearly identical no matter the inert gas is NEA or MIG. However, the ullage and dissolved oxygen concentrations of MIG scrubbing are always higher than those of NEA scrubbing.     

实时数据处理结果动态选优方法研究

针对传统的实时数据处理结果按方案优先级选优输出方法存在的缺陷,提出一种结合实时数据处理结果的精度进行实时动态选优的方法。该方法在每个数据处理周期将所有的数据结果与数据融合处理结果相比较,按照误差值大小对处理结果进行排序,若当前选择输出结果的误差值大于其他结果的误差值,可采用人机交互方式进行动态切换,选择其他精度高的结果输出。实际应用证明,该方法能有效避免当测量方案优先级高的数据处理结果精度差时其结果被选优输出的问题,提高了实时数据处理结果的精度。     

自主学习环境中原声电影赏析的教师干预效果

在自主学习中心大部分学生选择观看原声电影作为主要的学习手段,但学生在电影赏析时缺乏明确的学习目标和可行的学习方法.本文在介绍实验操作的具体步骤后,通过对比分析实验对象在实验前后的考试数据,证明了教师合理科学地干预学生原声电影赏析活动,可以让学生收获更好的语言学习效果.