MPI和Pthread混合编程在NCS算法中的设计和实现

根据星载合成孔径雷达（Synthetic Aperture Radar,SAR）实时和准实时成像的需求,论文设计和实现了一种混合编程模式的非线性CS（Nonlinear Chirp Scaling, NCS）成像算法。此方法基于SMP（Symmetric Multiprocessing）集群系统,利用MPI（Message Passing Interface）和Pthread混合编程,实现了多进程和多线程的两级流水线并行成像处理。通过在HP刀片系统上的实验验证和结果分析,这种混合编程的流水线NCS并行成像算法既能较好适应前端系统传输一景原始回波数据时间不小于8s的情况,又能较好适应大规模原始回波数据堆积并且等待处理的情况。     

激光探潜系统中杂散光抑制措施分析

杂散光会引起像质模糊和对比度下降,降低像面的信噪比,严重影响了光学系统的成像质量,必须进行消除。针对激光探潜系统中红外光和蓝绿光分离的光学系统,分析了红外系统中杂散辐射和蓝绿光系统中杂散光来源,给出了相应的杂散辐射和杂散光的抑制措施,为激光探潜系统光学系统的进一步优化设计提供了参考,展望了消杂光技术未来的发展趋势。     

Effects of punch size,magnetic field,and magnetorheological elastomers medium on forming T-shaped thin-walled Inconel 718 tubes

This study aims at investigating the impact of using the Magnetorheological Elastomers(MREs) medium to improve the formability of T-shaped Inconel 718 tubes during the bulging process. Besides, the influence of the punch size and the intensity of the magnetic field on the branch height and wall thickness distribution of the T-shaped Inconel 718 tubes are also explored. The results showed that the parts formed by the punch with a length of 5 mm in the pressurization zone have better forming quali...     

全数字接收机中的并行插值技术研究

文章针对全数字接收机提出了一种并行插值结构.它不同于以往的串行插值,一次可以计算出一个符号内所需的所有插值点.这个特点改善了硬件中对插值计算的速度限制,提升了全数字接收机的性能.同时仿真结果表明,该并行插值结构可以很好的调整定时误差,适合应用在高速率的数据通信中.     

O2 evolution and cyclic electron flow around photosystem I in long-term ground batch culture of Euglena gracilis

Based on the purpose of better exploring the function of green producers in the closed aquatic biological life support system, the condition of dynamic O₂ evolution and performance of cyclic electron flow around photosystem I (CEF-PSI) in long-term ground batch culture of Euglena gracilis were studied, the relationship between linear electron flow (LEF) and CEF-PSI was revealed, the function of CEF-PSI was investigated. Excellent consistency in O₂ evolution pattern was observed in cultures grown in both closed and open containers, O₂ evolution was strictly suppressed in phase 1, but the rate of it increased significantly in phase 2. CEF-PSI was proposed to be active during the whole course of cultivation, even in the declining phase 3, it still operated at the extent of 47–55%. It is suggested that the relationship between LEF and CEF-PSI is not only competition but also reciprocity. CEF-PSI was proposed to contribute to the considerable growth in phase 1; it was also suggested to play an important protective role against photosystem II (PSII) photoinhibition at the greatly enhanced level (approximately 80–95%) on the 2nd day. Our results in this research suggest that E. gracilis had very particular photosynthetic characteristics, the strict O₂ evolution suppression in the initial culture phase might be a special light acclimation behavior, and CEF-PSI could be an important mechanism involved in this kind of adaptation to the changeable light environment.     

Effects of different carbon dioxide and LED lighting levels on the anti-oxidative capabilities of Gynura bicolor DC

Gynura bicolor DC is not only an edible plant but also a kind of traditional Chinese herbal medicine. G. bicolor DC grown in controlled environmental chambers under 3 CO₂ concentrations [450 (ambient), 1500 (elevated), 8000 (super-elevated) μmol mol⁻¹] and 3 LED lighting conditions [white (WL), 85% red + 15% blue (RB15), 70% red + 30% blue (RB30) ] were investigated to reveal plausible antioxidant anabolic responses to CO₂ enrichment and LED light quality. Under ambient and elevated CO₂ levels, blue light increasing from 15% to 30% was conducive to the accumulation of anthocyanins and total flavonoids, and the antioxidant activity of extract was also increased, but plant biomass was decreased. These results demonstrated that the reinforcement of blue light could induce more antioxidant of secondary metabolites, but depress the effective growth of G. bicolor DC under ambient and elevated CO₂ levels. In addition, compared with the ambient and elevated CO₂ levels, the increased anthocyanins, total flavonoids contents and antioxidant enzyme activities of G. bicolor DC under super-elevated CO₂ level could serve as important components of antioxidative defense mechanism against CO₂ stress. Hence, G. bicolor DC might have higher tolerance to CO₂ stress.     

采用连续旋转检偏器的天空偏振光探测装置设计与实现

为了实现对运动目标与天空散射光的偏振分布模式进行快速、有效的探测,根据连续旋转检偏器光强度透射的数学模型,利用光电传感器的积分特性,设计并构建了采用连续旋转检偏器的偏振成像探测装置。测试结果表明,该装置对偏振光的角度的测量精度优于0.069°（3σ）,偏振度的测量精度优于0.12%（3σ）。一幅偏振图像的探测时间达到0.7s。在偏振度低于4%的情况下,仍可以探测到有规律的偏振分布模式,其抵抗恶劣天气的性能优于现有的偏振导航探测装置。     

An improved procedure for manufacture of 3D tubes with springback concerned in flexible bending process

Three dimensional (3D) tubes, which possess the characteristics of space saving, lightweight and high strength, are widely used in many high-end industries such as aviation, aerospace, automobile and shipbuilding. However, when manufacturing a 3D tube in flexible bending process, springback is a big obstacle for improving the forming quality. In this paper, a new comprehensive strategy for springback control of 3D tubes is proposed. The strategy can be described as follows: (1) define the desired shape and manufacture shape; (2) optimize the manufacture shape using two tooling design methods (e.g. DA (displacement adjustment) method and B&T (bending and twisting) method presented in this paper); (3) make a discretization of the manufacture shape to acquire the optimized forming parameters. Additionally, experiment is implemented to validate the effectiveness of the new strategy. Results show that forming parameters acquired by the new strategy are partially effective. The new strategy also demonstrates that, during 3D tubes forming, the deviation caused by over-bent elements can be counteracted by the deficient-bent elements. This principle is helpful to reduce the difficulty of parameter determination in future.     

高压氧气黄铜管路连接件设计与应用

根据高压氧气特殊的化学性质和高压氧气供应系统使用要求,参考航天QJ2889系列37。导管连接件标准,设计了DN4,DN10和DN20的黄铜球头、焊接直通等连接件,并进行了强度校核、强度及密封性试验。系统建设后经正式应用验证,确认黄铜连接件设计满足了高压氧气系统使用要求,解决了黄铜管路与不锈钢管路互连的技术难题。     

航星座自主运行平行系统的轨道计算方法

构建一个能够与实际卫星导航系统长期保持时空一致的平行系统,可为导航星座自主运行提供一个监视与评估平台。针对建设该平行系统所需的高逼真轨道计算问题,引入平行系统理论的思想,在分析历史精密轨道的基础上,提出高精度轨道计算与预报方法。该方法以不断更新的精密轨道作为输入,利用PID增量式算法或时变加权法进行数据平滑,使得轨道计算结果始终与实际系统保持高度一致性。试验结果表明,该方法可使卫星轨道计算的结果与实际卫星轨道长期保持在分米量级。