离箱扰动和折叠翼展开数学模型研究

根据箱式发射导轨与导弹，导弹与折叠翼的约束特点，应用动力学普遍定理和解除约束原理，创建了离箱扰动运动数学模型和拆卸叠翼展开过程计算数学模型，并将计算结果与飞行试验结果作了比较。     

Geometry and size optimization of stiffener layout for three-dimensional box structures with maximization of natural frequencies

Based on the growth mechanism of natural biological branching systems and inspiration from the morphology of plant root tips, a bionic design method called Improved Adaptive Growth Method (IAGM) has been proposed in the authors’ previous research and successfully applied to the reinforcement optimization of three-dimensional box structures with respect to natural frequencies. However, as a kind of ground structure methods, the final layout patterns of stiffeners obtained by using the IAGM are highly subjected to their ground structures, which restricts the optimization effect and freedom to further improve the dynamic performance of structures. To solve this problem, a novel post-processing geometry and size optimization approach is proposed in this article. This method takes the former layout optimization result as start, and iteratively finds the optimal layout angles, locations, and lengths of stiffeners with a few design variables by optimizing the positions of some specific node lines called active node lines. At the same time, thicknesses of stiffeners are also optimized to further improve natural frequencies of three-dimensional box structures. Using this method, stiffeners can be successfully separated from their ground structures and further effectively improve natural frequencies of three-dimensional box structures with less material consumption. Typical numerical examples are illustrated to validate the effectiveness and advantages of the suggested method.     

空间遥操作分段自适应碰撞预警方法

目前空间遥操作碰撞预警机制并未考虑遥操作任务的阶段性特点,操作的快速性与精细性难以兼顾。针对这一现状,提出了空间遥操作分段自适应碰撞预警方法。通过计算机械手末端与操作目标之间的相对距离,将遥操作任务划分为自由接近、精细调整和操作控制三个阶段,分阶段自适应调整碰撞检测策略和操作比例系数,并通过直观的预警视觉信息,使得遥操作员实时感知任务阶段。目标逼近试验表明:在自由接近段,随着对目标的逼近,操作速度从7.46mm/s逐渐减小为4.41mm/s,关节运动和相对位置的抖动较大;在精细调整段,操作速度为3.98mm/s,关节运动和相对位置的抖动较小。因此,该分段自适应碰撞预警方法有效克服了操作快速性与精细性的矛盾,适合于未来更为精细、复杂的空间遥操作任务。     

机翼盒段结构优化分析

机翼在飞机飞行过程中产生升力,是飞机能够飞行的根本保障。翼盒是机翼的主要承力部件,承受机翼上产生的所有载荷。所以翼盒的结构设计,对机翼甚至整个飞机的影响有着至关重要的作用。好的结构设计不仅能够保证机翼产生正常的气动升力,以及机翼内系统的正常运作,而且能够充分发挥材料的性能优势,减轻结构重量。因此,结构优化设计技术开始广泛被使用。总结翼盒优化的工作,包括不同的结构布局形式,不同的气动压心位置,不同的发动机吊挂位置以及翼盒不同位置的结构尺寸优化,分析影响翼盒结构设计的因素,为机翼结构的初步设计打好基础。     

盒栅式电子倍增系统在不同路径下的模拟计算研究

利用CST软件对不同路径的盒栅式电子倍增系统进行建模,将相邻打拿极的排布分为“Z”型和“U”型。模拟计算这两种最小打拿极排布单元及其衍生路径下,电子倍增系统内电场分布、电子运行轨迹和电子倍增增益的差异。模拟结果显示,不同打拿极排布下电子倍增系统内的电场分布差异不大,但电子运行轨迹和电子倍增增益差别显著。结合盒栅式电子倍增系统实际装配的合理性,通过计算分析得出打拿极排布的基本原则,并在八级打拿极结构的情况下,优化得出较合理的排布路径。     

黑箱建模方法在环境模拟试验中的应用

某大型环境模拟试验设备中一些制冷设备的热力参数,如涡轮膨胀机的出口温度,很难用传统的计算公式来准确求解这一问题。文章提出了用黑箱建模方法来预测这些参数;运用多元回归分析和人工神经网络的方法对黑箱模型进行求解。通过试验数据的验证,表明预测值与试验值非常接近,说明该方法是一种简便易行、准确性高的计算方法。     

钛合金负角度圆框类零件热冲压成形工艺研究

结合某钛合金负角度半圆框零件的热冲压成形,提出了一种通过无侧压装置的热成形设备完成钛合金负角度圆框类零件成形的工艺方法。详细介绍了工艺方案的制定、模具结构的设计和工艺试验中遇到的零件底面不平度问题。     

Severe disruption of the cytoskeleton and immunologically relevant surface molecules in a human macrophageal cell line in microgravity—Results of an in vitro experiment on board of the Shenzhou-8 space mission

During spaceflight the immune system is one of the most affected systems of the human body. During the SIMBOX (Science in Microgravity Box) mission on Shenzhou-8, we investigated microgravity-associated long-term alterations in macrophageal cells, the most important effector cells of the immune system. We analyzed the effect of long-term microgravity on the cytoskeleton and immunologically relevant surface molecules. Human U937 cells were differentiated into a macrophageal phenotype and exposed to microgravity or 1g on a reference centrifuge on-orbit for 5 days. After on-orbit fixation, the samples were analyzed with immunocytochemical staining and confocal microscopy after landing. The unmanned Shenzhou-8 spacecraft was launched on board a Long March 2F (CZ-2F) rocket from the Jiuquan Satellite Launch Center (JSLC) and landed after a 17-day-mission. We found a severely disturbed actin cytoskeleton, disorganized tubulin and distinctly reduced expression of CD18, CD36 and MHC-II after the 5 days in microgravity. The disturbed cytoskeleton, the loss of surface receptors for bacteria recognition, the activation of T lymphocytes, the loss of an important scavenger receptor and of antigen-presenting molecules could represent a dysfunctional macrophage phenotype. This phenotype in microgravity would be not capable of migrating or recognizing and attacking pathogens, and it would no longer activate the specific immune system, which could be investigated in functional assays. Obviously, the results have to be interpreted with caution as the model system has some limitations and due to numerous technical and biological restrictions (e.g. 23 °C and no CO₂ supply during in-flight incubation). All parameter were carefully pre-tested on ground. Therefore, the experiment could be adapted to the experimental conditions available on Shenzhou-8.     

基于盒粒子滤波的低成本皮纳卫星高效姿态确定算法

针对低成本皮纳卫星姿态确定系统在质量、体积、计算量以及能耗等方面的限制问题,本文基于区间分析理论提出了卫星姿态区间化描述方法并建立了运动学区间化方程,提出了基于盒粒子滤波(BPF)的皮纳卫星姿态确定算法。该算法首先采用双矢量算法对太阳敏感器和磁强计得到的量测进行姿态解算,并将解算出的姿态四元数作为伪量测值输入传递给BPF,从而降低敏感器噪声对估计精度的影响。仿真实验表明,相比于传统粒子滤波的姿态确定算法,本文所提出的BPF姿态确定算法能够在保证姿态确定精度的同时大幅缩短算法运行时间。     

SCA在大规模软件无线电系统中的应用分析及其改进方案

介绍了软件通信体系架构（SCA）在军用和民用领域的发展现状,分析了 SCA 给软件定义无线电（SDR ）系统实现带来的诸多益处,指出SCA在大规模SDR系统实现过程中的不足之处,最后给出大规模SDR系统中SCA的改进方案,并总结了方案带来的优势以及后续研究计划。