Vertical crustal motion derived from satellite altimetry and tide gauges,and comparisons with DORIS measurements

A somewhat unorthodox method for determining vertical crustal motion at a tide-gauge location is to difference the sea level time series with an equivalent time series determined from satellite altimetry. To the extent that both instruments measure an identical ocean signal, the difference will be dominated by vertical land motion at the gauge. We revisit this technique by analyzing sea level signals at 28 tide gauges that are colocated with DORIS geodetic stations. Comparisons of altimeter-gauge vertical rates with DORIS rates yield a median difference of 1.8 mm yr⁻¹ and a weighted root-mean-square difference of 2.7 mm yr⁻¹. The latter suggests that our uncertainty estimates, which are primarily based on an assumed AR(1) noise process in all time series, underestimates the true errors. Several sources of additional error are discussed, including possible scale errors in the terrestrial reference frame to which altimeter-gauge rates are mostly insensitive. One of our stations, Malè, Maldives, which has been the subject of some uninformed arguments about sea-level rise, is found to have almost no vertical motion, and thus is vulnerable to rising sea levels.     

一种SMART显示器画面的设计与仿真方法

针对当前SMART显示画面及其画面描述文件设计验证方法的缺点,提出了一种SMART显示器画面的设计与仿真方法,通过对SMART显示机制的分析,抽象出其画面构成原理、画面控制原理、数据驱动原理和画面描述文件的设计原理,通过搭建仿真环境,在设计阶段即可便捷地对画面设计和画面描述文件进行设计仿真.     

一种可配置组关联cache的行为级设计

组关联的cache在当前微处理器中广泛应用，cache是一个验证难度比较大的模块。如何缩短cache验证周期对缩短开发处理器的周期有重要意义。建立了一个可配置的组关联cache的行为级模型。可作为微处理器设计中cache验证的参考模型。     

结构故障诊断中的小波分解层数选取方法研究

小波变换被广泛的应用到结构故障诊断中,但尽管利用小波变换进行故障诊断效果很好,在实际操作过程中仍存在两个问题,即小波基函数的选择和最佳小波分解层数的选择。基于结构的动力系统,通过讨论结构动力响应、频率折叠及频率混淆对小波分解层数的影响,推导总结出一种小波分解层数的算法,并给出了其算法公式。     

压气机特性曲线精确分步拟合方法研究

针对压气机特性曲线分步拟合中坐标变换方法不明确的问题,提出先对压比进行坐标变换,坐标变换中的参数对折合转速进行拟合,之后折合流量或效率分两步对压比和折合转速进行拟合的改进方法。用多个指标对拟合结果进行了评估,给出了拟合阶次的选取方法。实例说明了改进方法的有效性,进一步说明了拟合中坐标变换的意义,以及第二步系数拟合中牛顿插值法和最小二乘法的适用情形。     

硅微谐振加速度计的研究现状及发展趋势

硅微谐振加速度计具有体积小、 功耗低、 准数字量输出和精度提升大的优点,是一种具有良好应用前景的高精度MEMS惯性仪表.总结分析了近些年国内外在硅微谐振加速度计方面的研究现状,主要在结构设计及工艺、 测控电路设计等方面阐述了各自特点.最后,结合近些年MEMS惯性仪表的发展趋势,对硅微谐振加速度计晶圆级真空封装、 测控电路数字化、仪表补偿智能化3个发展方向进行了展望.     

复合式直升机技术发展分析

首先根据旋翼技术的特点和复合推进方式的不同,将复合式直升机分成5个类别,分别对5类复合式直升机的发展历程做了扼要介绍。然后,通过技术成熟度与市场需求的发展分析,将复合式直升机的发展归纳为5个阶段,总结了国外复合式直升机的型号发展过程和规律。最后,结合国外发展复合直升机的经验,以及中国直升机技术水平、科研机制的特点,针对中国复合式直升机技术发展提出了一些建议。     

Change rules of a stratospheric airship's envelope shape during ascent process

Stratospheric airship is a special near-space air vehicle, and has more advantages than other air vehicles, such as long endurance, strong survival ability, excellent resolution, low cost, and so on, which make it an ideal stratospheric platform. It is of great significance to choose a rea-sonable and effective way to launch a stratospheric airship to the space for both academic research and engineering applications. In this paper, the non-forming launch way is studied and the method of differential pressure gradient is used to study the change rules of the airship's envelope shape dur-ing the ascent process. Numerical simulation results show that the head of the envelope will main-tain the inflatable shape and the envelope under the zero-pressure level will be compressed into a wide range of wrinkles during the ascent process. The airship's envelope will expand with the ascent of the airship and the position of the zero-pressure level will move downward constantly. At the same time, the envelope will gradually form a certain degree of stiffness under the action of the inner and external differential pressure. The experimental results agree well with the analytical results, which shows that the non-forming launch way is effective and reliable, and the analytical method has exactness and feasibility.     

交换环上高层序与赋值对的相容性

本文的主要目的是把域上高层序与赋值对的相容性推广到含单位元的交换环上来。本文提出了交换环上高层序与赋值对相容的概念,由此得到高层序与赋值对相容的四个等价条件。本文的关键是藉助于赋值环的凸性来刻划高层序与赋值对的相容性。本文的方法是通过取序的特殊化以及整环的商域,使环的情形下的问题转化到域的情形来解决。     

模型驱动的软件构件研制保证水平验证方法

在机载软件架构设计阶段,人们将安全性研制保证水平分配到具体的构件中,确保产品质量。鉴于现代航空软件系统极其复杂,如何从系统角度,检验分配给构件的安全性等级符合系统的一致性目标,是设计阶段需要解决的重要问题。首先,分析了分布式和综合式机载软件系统的架构特点,得出了在安全性分析工作中需要考虑冗余等架构设计的影响的结论。其次,使用系统建模语言(SysML)块图建立带有安全性等级属性的系统静态结构模型,利用矩阵对模型进行精确的形式化转换;制定验证规则,在此基础上给出了验证方法,以验证安全性等级分配的合理性。在验证过程中,将关键信息存储在XML文档中,可为适航性审查提供证据。最后,通过实例分析,验证了该方法的可行性。