VxWorks环境下捷联惯导系统的软件设计

介绍了VxWorks实时操作系统实时性和多任务环境的特性。在分析了捷联惯导系统基本原理的基础上，提出捷联惯导系统各个任务模块的划分原则，介绍了各个任务的优先级别和触发方式，提出了各个任务间的通信手段与同步方法。此外，还给出了在PC-104嵌入式计算机上，应用VxWorks实时操作系统成功开发捷联惯导系统软件的实例。     

基于OMAPL138 FPGA构架的PC104主板检测系统

为了对PC104主板进行自动检测,分析了PC104主板工作原理及其总线时序,提出了一种基于ARM FPGA的嵌入式检测系统的设计方案。该方案采用德州仪器(TI)双核架构的高性能芯片OMAPL138中的ARM核来实现检测系统的应用管理,DSP核实现数据的处理,并利用FPGA技术来实时采集PC104总线数据。检测系统在Linux操作系统下,通过人机交互方式实现了PC104主板的各种功能的自动检测。实验结果显示该检测快速可靠,为PC104主板的自动检测提供了一种有效的方法。     

光纤捷联航姿基准系统的设计与实现

针对光纤陀螺仪及捷联系统的特点,研究并实现了一种基于光纤陀螺仪的捷联航姿基准系统。以PC/104作为导航计算机,采用I/F转换回路及计数线路构成加速度计的数字信号采集系统,采用智能多串口线路完成各模块之间的通讯任务,构成捷联式航姿基准系统原理样机。在此基础上,设计了系统的机械编排方案、传感器的误差补偿方案和闭环卡尔曼滤波器。样机的测试结果表明:样机满足系统设计要求,在温控环境中,其精度优于基于挠性陀螺仪的捷联航姿系统。     

Mean stability of stochastic difference systems

In this paper the mean stability of linear and non-linear stochastic difference systems is considered. For linear systems the relationship between mean stability and other stability definitions is explored. For the non-linear system explicit criteria for mean stability are derived when the non-linear term satisfies a certain realistic condition.     

Merging covering arrays and compressing multiple sequence alignments

Covering arrays have been extensively studied, in part because of their applications in testing interacting software components. In this setting, fast and flexible methods are needed to construct covering arrays of close-to-minimum size. However testing scenarios often impose additional structure on the tests that can be selected. We extend a greedy method to construct test suites for complex systems that have a hierarchical structure in which components combine to form subsystems, which in turn form larger subsystems, until the entire system is formed. The algorithm for merging covering arrays that we propose is then shown to have further potential application in the compression of multiple sequence alignments of genomic data.     

On the α-invariants of cubic surfaces with Eckardt points

In this paper, we show that the αm,2-invariant (introduced by Tian (1991) [27] and (1997) [29]) of a smooth cubic surface with Eckardt points is strictly bigger than . This can be used to simplify Tian's original proof of the existence of Kähler-Einstein metrics on such manifolds. We also sketch the computations on cubic surfaces with one ordinary double points, and outline the analytic difficulties to prove the existence of orbifold Kähler-Einstein metrics.     

A New and Efficient Synthesis of the HMG‐CoA Reductase Inhibitor Pitavastatin

A new synthetic method for the preparation of pitavastatin is described. The approach circumvents various synthetic problems associated with the buildup of the 3,5‐dihydroxy‐C₇ acid side chain of HMG‐CoA reductase inhibitors (statins). The use of the C₆‐amide derivative 5 instead of ester derivatives in the coupling reaction with carboxaldehyde 8 (Scheme 3) prevents undesired side reactions, such as eliminations and retro‐aldol reactions. The method provides synthetic statins, such as pitavastatin, in >99% ee and exceptionally high overall yield. The enantiomerically pure starting material, (3S)‐3‐{[(tert‐butyl)dimethylsilyl]oxy}‐5‐oxo‐5‐{[(1S)‐1‐phenylethyl]amino}pentanoic acid ( 3c ), is prepared by an improved procedure from 3‐{[(tert‐butyl)dimethylsilyl]oxy}glutaric anhydride ( 1 ) and (1S)‐1‐phenylethylamine ( 2c ; Scheme 1).     

Enzymatic Hydrolysis of Penicillin for 6-APA Production in Three-Liquid-Phase System

A dodecane/thermosensitive polymer/water three-liquid-phase system was introduced for enzymatic hydrolysis of penicillin G (Pen G) for 6-aminopenicillanic acid (6-APA). The enzyme was covalently attached to the terminal of PEO–PPO–PEO polymer (L63), which would be transferred into a polymer coacervate phase at high temperature above its “cloud point”. 6-APA was primarily resided in the aqueous phase due to its zwitterionic nature. More than 70% phenylacetic acid (PAA) was transferred into the organic phase using trioctylmethylammonium hydroxide and trihexyl-(tetradecyl)phosphonium bis 2,4,4-trimethylpentylphosphinate ionic liquids (Cyphos IL-104) mixture at pH 5.5, while most of Pen G resided in water. As a result, high operational pH was permitted in three-liquid-phase system, which leads to higher enzymatic activity (120 IU at 40°C) and stability (enzymatic half-time up to 55 h at 60°C) in comparison with the value in butyl acetate/water two-phase system. On the other hand, two products in three-liquid-phase system might be automatically separated from the enzyme sphere into different phases at the same time, which facilitated the reaction equilibrium towards the product’s side with 6-APA productivity of 80% at 42°C, pH 5.5. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Search for Superheavy Elements in the Nature

The existence of relatively stable elements beyond the present Periodic Table is predicted by various theoretical calculations. Considering all experiments of the search for superheavy elements (SHE) in nature and their non definite positive results further search seems to be pessimistic. Nevertheless in this work the scientific necessity to continue the search in nature by a modified manner using industrial enrichment steps is pointed out.     

LEVEL DENSITY AND FINITE-TEMPERATURE SPECIFIC HEAT OF NUCLEUS 104Pd UNDER MICROSCOPIC IBM

By using the microscopic sdgIBM-F_max approach, procedure of canonical ensemble average and saddle point approximation, thermodynamics of nucleus is established under microscopic IBM. Calculations of spectrum, level density and finite-temperature specific heat for the nucleus ¹⁰⁴Pd are carried out. The calculated values are coincident with the experimental data reported recently. The results predict that the shape phase transition in ground state band appears at about T≈0.230MeV and the phase transition of thermal excitation mode takes place at T≈0.630MeV for nucleus ¹⁰⁴Pd.