当量名义应力和变幅载荷下结构DFR的确定

1.当量名义应力及K_f和DFR之间的关系 当量名义应力定义为:在变幅载荷作用下结构危险部位的局部应力-应变水平对应的相同寿命的常幅名义应力水平。当量名义应力水平的确定方法详见文献。计算当量名义应力时必须用到结构的疲劳强度减缩系数K_f。 根据K_f的定义     

基于傅里叶变换的HY-1B卫星影像条带噪声去除

HY-1B卫星是中国第二颗海洋遥感卫星,水色水温扫描仪（COCTS）是其主要载荷。文章针对COCTS图像条带噪声的特点,采用傅里叶变换方法,设计了一种新的滤波器,对图像进行条带噪声去除．并同传统的低通滤波方法处理结果进行比较。实验结果表明,新的傅里叶变换方法能够有效地去除图像的条带噪声,其去除效果要优于传统的低通滤波方法。     

固体微推力器阵列的推力估计与分配补偿方法

针对固体微推力器阵列(SPMA)中微推力器一次性点火,推力测试中难以获得精确推力的特点,为实现推力在线估计和实时补偿,提出一种利用二次规划对微推力器阵列推力进行估计,同时结合混合整数规划算法进行推力分配的方法,对估计算法收敛性以及控制系统稳定性进行了分析。该方法在不修改控制律的前提下,对推力器推力进行在线估计,并采用推力分配的方法实时补偿推力器出现的推力偏差,对系统稳定性的分析证明该方法可以保证系统的有界稳定。将其应用到微纳卫星编队保持中,仿真结果表明,在微推力器阵列出现推力偏差的情况下,该方法能很好地补偿推力偏差对控制系统造成的影响。     

ACL模型在训练科目选择中的应用

美国军用手册MIL-HDBK-29612A中在对训练科目选择中介绍了ACL模型的应用,本文对ACL模型进行了简要介绍,并以航空发动机车间维修工作的训练为例,介绍了ACL模型的用法。     

Simulated microgravity inhibits the proliferation of K562 erythroleukemia cells but does not result in apoptosis

Astronauts and experimental animals in space develop the anemia of space flight, but the underlying mechanisms are still unclear. In this study, the impact of simulated microgravity on proliferation, cell death, cell cycle progress and cytoskeleton of erythroid progenitor-like K562 leukemia cells was observed. K562 cells were cultured in NASA Rotary Cell Culture System (RCCS) that was used to simulate microgravity (at 15 rpm). After culture for 24 h, 48 h, 72 h, and 96 h, the cell densities cultured in RCCS were only 55.5%, 54.3%, 67.2% and 66.4% of the flask-cultured control cells, respectively. The percentages of trypan blue-stained dead cells and the percentages of apoptotic cells demonstrated no difference between RCCS-cultured cells and flask-cultured cells at every time points (from 12 h to 96 h). Compared with flask-cultured cells, RCCS culture induced an accumulation of cell number at S phase concomitant with a decrease at G0/G1 and G2/M phases at 12 h. But 12 h later (from 24 h to 60 h), the distribution of cell cycle phases in RCCS-cultured cells became no difference compared to flask-cultured cells. Consistent with the changes of cell cycle distribution, the levels of intercellular cyclins in RCCS-cultured cells changed at 12 h, including a decrease in cyclin A, and the increasing in cyclin B, D1 and E, and then (from 24 h to 36 h) began to restore to control levels. After RCCS culture for 12–36 h, the microfilaments showed uneven and clustered distribution, and the microtubules were highly disorganized. These results indicated that RCCS-simulated microgravity could induce a transient inhibition of proliferation, but not result in apoptosis, which could involve in the development of space flight anemia. K562 cells could be a useful model to research the effects of microgravity on differentiation and proliferation of hematopoietic cells.     

分布式虚拟靶试系统中负载平衡机制设计与实现

针对大规模分布式交互仿真系统的开发需求,基于MAK／RTI深入研究了分布式仿真系统的负载平衡技术,并在分布式虚拟靶试系统中得到应用与验证。     

双电机驱动消隙技术及其在数控设备中的应用

根据传动间隙对设备的影响,提出了一种采用双电机驱动消除机械间隙的新方法,并以伺服主从驱动技术为理论基础,论述了双电机驱动消隙技术的原理和实现手段。最后,介绍了在西门子840D数控系统和611D伺服系统环境下,双电机驱动消隙技术在自动制孔设备中的实际应用情况。     

UQS独特码设计

UQS独特码要求它被自然界偶然产生的概率尽可能小,根据UQS码的8条数学标准设计出标准判别的编码生成算法,编程得到了20个UQS码的精简码集,生成的UQS码均符合UQS标准,能够作为要害系统的解保密码。     

基于逆ω-κ算法的SAR欺骗干扰方法

提出一种新的SAR欺骗干扰方法,其基本原理是干扰机在SAR副瓣区域快速生成覆盖保护区域的干扰信号,然后按照SAR发射信号的重复频率逐条发射干扰信号,最终使得干扰图像融合到真实场景之中,破坏和掩盖真实图像中的一些重要特征。为了实现快速的场景目标干扰,文中结合逆ω-κ算法,将一幅雷达灰度图转化为干扰信号。仿真试验表明,该方法可以有效实现对SAR的欺骗式干扰。     

某涡轴发动机起动不成功分析

对某型发动机外场起动不成功试验数据进行分析,并通过燃油喷嘴低油压雾化试验及整机起动时的温度场测量验证,确认燃油喷嘴喷口积炭后,燃油喷嘴喷雾锥角减少,燃油雾化质量恶化,直接影响到发动机起动时火焰联焰的可靠性,对发动机起动性能产生较大影响.涡流器插入深度对涡流器出口喷雾的部件研究试验结果显示:插入深度对涡流器出口喷雾无影响;整机模拟外场使用结果表明:发动机在不大于30%功率的低状态长期使用,离心式燃油喷嘴容易出现积炭.