Air route network optimization in fragmented airspace based on cellular automata

Air route network optimization,one of the essential parts of the airspace planning,is an effective way to optimize airspace resources,increase airspace capacity,and alleviate air traffic con gestion.However,little has been done on the optimization of air route network in the fragmented airspace caused by prohibited,restricted,and dangerous areas (PRDs).In this paper,an air route network optimization model is developed with the total operational cost as the objective function while airspace restriction,air route network capacity,and non-straight-line factors (NSLF) are taken as major constraints.A square grid cellular space,Moore neighbors,a fixed boundary,together with a set of rules for solving the route network optimization model are designed based on cellular automata.The empirical traffic of airports with the largest traffic volume in each of the 9 flight information regions in mainland China is collected as the origin-destination (OD) air port pair demands.Based on traffic patterns,the model generates 35 air routes which successfully avoids 144 PRDs.Compared with the current air route network structure,the number of nodes decreases by 41.67％,while the total length of flight segments and air routes drop by 32.03％ and 5.82％ respectively.The NSLF decreases by 5.82％ with changes in the total length of the air route network.More importantly,the total operational cost of the whole network decreases by 6.22％.The computational results show the potential benefits of the model and the advantage of the algorithm.Optimization of air route network can significantly reduce operational cost while ensuring operation safety.     

强不确定系统“全系数之和等于1”的实现方法

摘要： 研究强不确定系统“全系数之和等于1”的实现方法，强不确定系统指的是系统的静态增益及其界不完全确知且范围较大.“全系数之和等于1”是吴宏鑫院士20世纪80年代发现的，该原理表明，对于未知连续系统，其离散化系统的系数的和在一定条件下是1.该原理的发现对于解决闭环辨识和自适应控制的瓶颈问题具有关键作用.“全系数之和等于1”是在一定条件下成立的.为了实现系统的“全系数之和等于1”，需要对系统进行一定的变换，以满足所需条件.其中，采用静态增益的标称值的倒数进行输入变换的方法在实际中得到了广泛应用.但是，当系统的不确定性较大时，该变换将带来较大偏差.针对该问题开展了深入研究，明确给出了系统静态增益的不确定性与标称值的比值的关系对于实现“全系数之和等于1”的影响.当不确定性与标称值的比值较小时，可以近似实现“全系数之和等于1”；当比值较大时，进一步给出了通过选取合适的采样周期，近似实现“全系数之和等于1”的方法.本文的研究对于特征模型理论在实际中的应用提供了一定的基础.     

基于Visual Basic的互感器负荷箱测量仪校准系统的实现

为解决互感器负荷箱测量仪同相分量和正交分量的校准问题,在分析互感器负荷箱测量仪工作原理的基础上,设计了基于电子/电工组合式的互感器负荷箱测量仪校准装置,并简要说明装置电工部分、电子部分以及上位机软件的实现。经省级计量研究院验证结果表明,该装置校准结果符合0.2级要求,可作为标准装置解决1级互感器负荷箱测量仪量值溯源问题。     

飞机数字化装配系统中机身交点孔加工方法研究

针对传统交点孔加工方法加工精度低且存在回弹变形的问题,设计了一种满足飞机大部件数字化装配要求的机身交点孔精加工方法,根据交点孔的加工特性完成了机身定位与固持、数控加工中心定位以及加工工艺的总体设计,确定了交点孔加工程序原点的计算方法和编程原则,最后通过交点孔试切加工试验验证了加工方法的可行性。     

Application of small-size antennas for estimation of angles of arrival of HF signals scattered by ionospheric irregularities

A modification of the Doppler Interferometry Technique is suggested to enable estimating angles of arrival of comparatively broadband HF signals scattered by random irregularities of the ionospheric plasma with the use of small-size weakly directional antennas. The technique is based on the measurements of cross-spectra phases of the probe radiation recorded at least in three spatially separated points. The developed algorithm has been used to investigate the angular and frequency-time characteristics of HF signals propagating at frequencies above the maximum usable one (MUF) for the direct radio path Moscow-Kharkiv. The received signal spectra show presence of three families of spatial components attributed, respectively, to scattering by plasma irregularities near the middle point of the radio path, ground backscatter signals and scattering of the sounding signals by the intense plasma turbulence associated with auroral activations. It has been shown that the regions responsible for the formation of the third family components are located well inside the auroral oval. The drift velocity and direction of the auroral ionosphere plasma have been determined. The obtained estimates are consistent with the classical conception of the ionospheric plasma convection at high latitudes and do not contradict the results of investigations of the auroral ionosphere dynamics using the SuperDARN network.     

Flow mechanism between purge flow and mainstream in different turbine rim seal configurations

The rim seal is used to prevent mainstream ingestion to the gap between the vane of a turbine and its blade. In this article, the dolphin lip with a hook configuration and a large seal cavity with hook structures are designed based on the high-pressure turbine datum single shark lip rim seal configuration. The sealing effect and parameters of the flow field are measured by an experiment method and a numerical simulation is used to explain the mechanism. For three configurations, the effect of the leakage slot vortex on the efficiency of the seal and the influence of leakage vortex, generated by the interaction between purge flow and mainstream flow, are discussed in depth. The result shows that the reverse vortex formed by the dolphin lip rim seal with hook structure will increase the sealing efficiency. The seal configuration with a large cavity improves sealing efficiency to a greater extent than the datum structure. At different purge flow rates and with unequal seal structures, the purge flow produces three types of leakage vortices in the passage. Besides, the seal configuration with dolphin lip produces a Kelvin-Helmholtz instability at the interface of the purge and the mainstream flows at a low purge flow rate to induce new leakage vortex branches in the passage of the blade.     

Alfvén gravity waves in viscous solar plasma: Effect of the background flow

We study the Propagation and damping properties of Alfvén gravity waves in the presence of the vertical magnetic field in the viscous solar plasma under influence of the background flow by deriving a fourth order dispersion relation in terms of the Doppler shifted frequency. We derive the dispersion relation under WKB and Boussinesq approximation. We study the damping of Alfvén gravity waves for the wave frequencies less than and greater than the Brunt-Väisälä frequency. We find that the Brunt-Väisälä frequency divides the frequency ranges where the weakly or strongly damped oscillations occur. The background flow exhibits a strong effect on weakly damped oscillations and a weak effect on the strongly damped oscillations. We also notice that the damping of both the strong and weakly damped oscillations depend on the Brunt-Väisälä frequency and wave number. The effect of the background flow is also being governed by the Brunt-Väisälä frequency and wave number. We also study the properties of gravity wave mode after filtering the Alfvén wave mode by minimizing the magnetic field and noticed that the background flow shows a very strong effect on the gravity wave mode.     

涡轮流量计前导流件有限元计算分析

对涡轮流量计关键部件之一前导流件运用NX THERMAL/FLOW进行有限元计算分析,得出流量分离导致的大涡旋尾迹区易出现在前导流件尾部区域、前导流件叶片形状对此处流体速度变化具有较大影响的结论,为涡轮流量计和前导流件的设计提供了理论依据。     

先进航发旋转雾化喷嘴制造技术

喷射油道是一种高精度旋转雾化喷嘴,其非连续窄深端槽、窄深槽、3/4圆弧窄端槽为行业内少见结构.通过分析喷射油道特有结构的加工工艺,摸索油孔尺寸与燃油流量的匹配关系,解决了非连续深窄端槽、窄深槽、细微孔电火花成形加工、3/4圆弧窄端槽高效数控加工、高精度喷嘴孔流量调试等关键技术瓶颈,具有一定的指导意义和广阔的应用前景.     

阵风载荷减缓系统故障分析

阵风引起的额外载荷会引起飞机结构疲劳,降低结构使用寿命。采用非定常气动力有理函数拟合方法建立时域状态空间下的动力学系统,设计了阵风载荷减缓系统。研究了阵风载荷减缓系统3种典型故障模式(副翼偏转饱和、舵机卡死、副翼偏转延时)的力学建模方法,并对机翼在阵风减缓系统故障模式下的阵风响应进行分析。仿真结果表明,3种故障模式均不利于阵风载荷减缓系统对阵风载荷的减缓,对于一些特定情况,故障模式下的阵风载荷减缓系统不仅不能减缓阵风载荷,还会带来由副翼偏转不当引起的额外负载。