液体火箭发动机泵动态特性水力试验研究

为了获取新一代大型运载火箭POGO稳定性分析及液体火箭发动机动力学研究等所必需的发动机泵动力学传递函数,进行了以常温水为试验介质、全尺寸降转速液氧/煤油补燃循环发动机氧泵的动态特性水力试验,对试验原理、试验模拟准则、隔离贮箱设计、激励系统设计、控制和测量分析系统设计、试验内容及数据分析方法等进行了深入探讨。通过试验成功地识别出泵的POGO动特性参数及参数的规律特点,为其他水力试验和真实介质试验储备经验。     

Variation of ionospheric total electron content in Taiwan region of the equatorial anomaly from 1994 to 2003

The ionospheric total electron content (TEC) in the northern hemispheric equatorial ionospheric anomaly (EIA) region is studied by analyzing dual-frequency signals of the Global Position System (GPS) acquired from a chain of nine observational sites clustered around Taiwan (21.9–26.2°N, 118.4–112.6°E). In this study, we present results from a statistical study of seasonal and geomagnetic effects on the EIA during solar cycle 23: 1994–2003. It is found that TEC at equatorial anomaly crests yield their maximum values during the vernal and autumnal months and their minimum values during the summer (except 1998). Using monthly averaged I_c (magnitude of TEC at the northern anomaly crest), semi-annual variations is seen clearly with two maxima occurring in both spring and autumn. In addition, I_c is found to be greater in winter than in summer. Statistically monthly values of I_c were poorly correlated with the monthly Dst index (r = −0.22) but were well correlated with the solar emission F_10.7 index (r = 0.87) for the entire database for the period during 1994–2003. In contrast, monthly values of I_c were correlated better with Dst (r ? 0.72) than with F_10.7 (r ? 0.56) in every year during the low solar activity period (1994–1997). It suggests that the effect of solar activity on I_c is a longer term (years), whereas the effect of geomagnetic activity on I_c is a shorter term (months).     

直升机金属结构的全范围安全S-N曲线确定方法

本文介绍了直升机结构安全S-N曲线的确定方法.在常用的三参数S-N曲线公式Stromeyer方程的基础上,根据直升机载荷的特点,介绍了一种适合直升机疲劳评定的全范围S-N曲线公式,并提供一套根据中值S-N曲线获得安全S-N曲线的方法.     

Specific features of the high-speed plasma stream cycles

The high-speed plasma streams in the solar wind are investigated during the solar cycles nos. 20–22 (1964–1996), separately on the two types of streams according to their solar origin: the HSPS produced by coronal holes (co-rotating) and the flare-generated, in keeping with the classification made in different catalogues. The analysis is performed taking into account the following high-speed stream parameters: the durations (in days), the maximum velocities, the velocity gradients and, the importance of the streams. The time variation of these parameters and the high-speed plasma streams occurrence rate show an 11-year periodicity with some differences between the solar cycles considered. A detailed analysis of the high-speed stream 11-year cycles is made by comparison with the “standard” cycles of the sunspot relative number (Wolf number). The different behaviour of the high-speed stream parameters between even and odd solar cycles could be due to the 22-year solar magnetic cycle. The increased activity of the high-speed plasma streams on the descendant phases of the cycles, regardless of their solar sources, proves the existence of some special local conditions of the solar plasma and the magnetic field on a large scale that allow the ejection of the high energy plasma streams. This fact has led us to the analysis the stream parameters during the different phases of the solar cycles (minimum, ascendant, maximum and, descendant) as well as during the polar magnetic field reversal intervals. The differences between the phases considered are pointed out. The solar cycles 20 and 22 reveal very similar dynamics of the flare-generated and also co-rotating stream parameters during the maximum, descendant and reversal intervals. This fact could be due to their position in a Hale Cycle (the first component of the 22-year solar magnetic cycle). The 21st solar cycle dominance of all co-rotating stream parameters against the 20th and 22nd solar cycle ones, during almost all phases, could be due to the same structure of a Hale Cycle – solar cycle 21 is the second component in a 22-year SC. During the reversal intervals, all high-speed stream parameters have comparable values with the ones of the maximum phases of the cycles even if this interval contains a small part of the descendant branch (solar cycles 20 and 22).     

Hamilton圈问题的DNA算法

基于目前可以使用的DNA实验技术并采用试管与表面相结合的方式,设计了解决H am ilton圈问题的DNA算法;详细地介绍了对图的顶点和边的分子编码;描述了算法的生物化学实现过程。由于采用了有控的部分穷举策略,因而既提高了解的可靠性,又抑制了大量伪解的产生。最后,讨论了算法的性能特点并指出进一步的研究方向。     

Solar terrestrial effects of two distinct types

The occurrence frequencies or fluxes of most of the solar phenomena show a 11-year cycle like that of sunspots. However, the average characteristics of these phenomena may not show a 11-year cycle. Among the terrestrial parameters, some related directly to the occurrence frequencies of solar phenomena (for example, ionospheric number densities related to solar EUV fluxes which show 11-year cycle like sunspots) show 11-year cycles, including the double-peak structures near sunspot maxima. Other terrestrial parameters related to average characteristics may not show 11-year sunspot cycles. For example, long-term geomagnetic activity (Ap or Dst indices) is related to the average interplanetary solar wind speed V and the total magnetic field B. The average values of V depend not on the occurrence frequency of ICMEs and/or CIRs as such, but on the relative proportion of slow and high-speed events in them. Hence, V values (and Ap values) in any year could be low, normal or high irrespective of the phase of the 11-year cycle, except that during sunspot minimum, V (and Ap) values are also low. However, 2–3 years after the solar minimum (well before sunspot maximum), V values increase, oscillate near a high level for several years, and may even increase further during the declining phase of sunspot activity, due to increased influence of high-speed CIRs (corotating interplanetary regions). Thus, Ap would have no fixed relationship with sunspot activity. If some terrestrial parameter shows a 11-year cycle, chances are that the solar connection is through the occurrence frequencies (and not average characteristics) of some solar parameter.     

Bifurcation in a 3-DOF Airfoil with Cubic Structural Nonlinearity

Limit cycle oscillations (LCOs) as well as nonlinear aeroelastic analysis of a 3-DOF aeroelastic airfoil motion with cubic restoring moments in the pitch degree of freedom are investigated.Aeroelastic equations of an airfoil with control surface in an incompressible potential flow are presented in the time domain.The harmonic balance (HB) method is utilized to calculate the LCO frequency and amplitude for the airfoil.Also the semi-analytical method has revealed the presence of stable and unstable limit cycles,along with stability reversal in the neighborhood of a Hopf bifurcation.The system response is determined by numerically integrating the governing equations using a standard Runge-Kutta algorithm and the obtained results are compared with the HB method.Also the results by the third order HB (HB3) method for control surface are consistent with the other numerical solution.Finally,by combining the numerical and the HB methods,types of bifurcation,be it supercritical,subcritical,or divergent flutter area are identified.     

基于军机全寿命周期BOM的质量信息数据库模型

针对军机制造过程越来越精细,质量要求越来越高,研究了军机全寿命周期制造过程中产生的各种BOM及BOM之间的关系;建立了质量信息数据库模型,并提出了军机架次质量信息数据库模板,对质量信息进行了有效的集成和共享,增强了对数据的传递性、完整性和准确性;为保证军机制造质量奠定基础.     

两轮升压式涡轮冷却器特性试验研究

针对两轮升压式涡轮冷却器的特点制订了涡轮和压气机的特性试验方案,分别按照折合参数整理了涡轮和压气机的特性试验数据,利用曲面拟合分别得到了涡轮和压气机的特性曲面方程。将10个校核点的试验数据与曲面方程得到的数据对比,误差在5%以内,证明试验方法和数据处理方法合理可行,对类似产品的特性试验具有借鉴意义。     

基于核心零部件聚类的飞机现场可更换单元划分

为研究军用飞机测试性设计过程中现场可更换单元（LRU）划分工作，以功能独立性和结构独立性为基本原则，以降低飞机维修保障成本和时间为主要目标，设计了一种军用飞机LRU划分方案。方案在首先实现了飞机从整机到零部件的功能结构分层划分基础上，从设备零部件层级出发，以综合重要度作为各零部件的定量化指标，运用帕累托（Pareto）原则筛选出核心零部件。然后基于核心零部件开发了一种LRU划分聚类算法，该算法以军用飞机设计研制阶段、使用保障阶段、退役处置阶段全寿命周期内成本和时间为优化目标构造综合评判因子，实现了非核心零部件与LRU模块之间的聚类组合，得到最优的LRU划分结果。最后以某型军用飞机上蒸发循环制冷装置为例，运用本文设计的方案实现了该装置LRU的划分，并将划分结果与该装置的实际LRU清单进行对比，通过维修保障成本和时间综合评判因子对两种划分结果的优劣性进行分析，得出本文设计方案得到的LRU划分结果对飞机维修保障成本和时间的优化效果较为均衡的结论。