分布式数据采集控制系统的现状及发展趋势

综述了ＤＣＳ系统的形成，现状及今后的发展方向，阐明了应用远智能Ｉ／Ｏ改进ＤＣＳ系统的优越性及向ＦＣＳ系统的过渡。     

An Integer Precise Point Positioning technique for sea surface observations using a GPS buoy

GPS data dedicated to sea surface observation are usually processed using differential techniques. Unfortunately, the precision of resulting kinematic positions is baseline-length dependent. So, high precision sea surface observations using differential GPS techniques are limited to coasts, lakes, and rivers. Recent improvements in GPS satellite products (orbits, clocks, and phase biases) make phase ambiguity fixing at the zero difference level achievable and opens up the observation of the sea surface without geographical constraints. This paper recalls the concept of the Integer Precise Point Positioning technique and discusses the precision of GPS buoy positioning. A sequential version of the GINS software has been implemented to achieve single epoch GPS positioning. We used 1 Hz data from a two week GPS campaign conducted in the Kerguelen Islands. A GPS buoy has been moored close to a radar gauge and 90 m away from a permanent GPS station. This infrastructure offers the opportunity to compare both kinematic Integer Precise Point Positioning and classical differential GPS positioning techniques to in situ radar gauge data. We found that Precise Point Positioning results are not significantly biased with respect to radar gauge data and that horizontal time series are consistent with differential processing at the sub-centimetre precision level. Nevertheless, standard deviations of height time series with respect to radar gauge data are typically [4–5] cm. The dominant driver for noise at this level is attributed to errors in tropospheric estimates which propagate into position solutions.     

生长在Si上的GaAs外延膜中有关深能级缺陷与其形貌间的关联研究

由于在GaAs和Si单晶材料间有着很大的格子常数及线性热膨胀系数差别，所以在St上生长的GaAs异质外延薄膜（GaAs／Si）中会存在着界面失配形变与高密度的结构缺陷。我们的实验显示，GaAs／Si外延膜的无序与其生长条件有关，尤其与其［As］／［Ga］比密切相关。与GaAs／Si无序相关的失配位错、线位错及畴区的形貌已用扫描电子显微镜作了观察;与深能级相关的缺陷与其形貌间的关联也已用实验说明。对于高有序GaAs／Si外延膜来说，其与离域相关的主发光峰的强度对温度的变化服从阿兰纽斯方程，而对低有序的GaAs／Si外延膜来说，其与局域相关的主发光峰的强度对温度的变化关系则遵循对无定型半导体才成立的另一种方程。     

Composition of the Volatile Material in Halley's Coma from In Situ Measurements

The investigation of the volatile material in the coma of comets is a key to understanding the origin of cometary material, the physical and chemical conditions in the early solar system, the process of comet formation, and the changes that comets have undergone during the last 4.6 billion years. So far, in situ investigations of the volatile constituents have been confined to a single comet, namely P/Halley in 1986. Although, the Giotto mission gave only a few hours of data from the coma, it has yielded a surprising amount of new data and has advanced cometary science by a large step. In the present article the most important results of the measurements of the volatile material of Halley's comet are summarized and an overview of the identified molecules is given. Furthermore, a list of identified radicals and unstable molecules is presented for the first time. At least one of the radicals, namely CH₂, seems to be present as such in the cometary ice. As an outlook to the future we present a list of open questions concerning cometary volatiles and a short preview on the next generation of mass spectrometers that are being built for the International Rosetta Mission to explore the coma of Comet Wirtanen. This revised version was published online in June 2006 with corrections to the Cover Date.     

全球精密单点定位性能评估

随着中国北斗三号卫星导航系统（BDS-3）全面建成与开通，北斗卫星导航系统已步入了新发展阶段，基于BDS-3实现全方位、多层次、高精度应用已成为地学研究中一项基本任务。利用全球最新均匀分布的10个MGEX跟踪站，分别从24 h内接收到的卫星数、卫星位置精度因子（PDOP）、卫星数据解算完整率和双频非组合精密单点定位（PPP）静态/动态定位精度等方面系统深入地评估了BDS-3在全球范围内的可用性。结果表明，测站对卫星跟踪能力与配备的接收机类型和区域位置有强相关性，单BDS-3卫星在全球范围内具有较强的连续定位能力，当使用SEPT POLARX5和JAVAD TRE_3接收机的情况下，数据解算完整率可达100%。此外，水平方向和高程方向定位精度分别优于2 cm和3 cm，并且在联合使用BDS-2和BDS-3定位的条件下，可使得静态定位精度在东、北和高程方向进一步提升37.6%,25.3%和38.9%。     

Multi-point observations and modeling of subauroral polarization streams (SAPS) and double-peak subauroral ion drifts (DSAIDs): A case study

While subauroral polarization streams (SAPS) are well recognized as representatively one of the most important features of magnetosphere-ionosphere (M-I) coupling processes in the subauroral region, the double-peak subauroral ion drifts (DSAIDs) is a newly recognized ionospheric phenomenon, categorized as a subset of subauroral ion drifts (SAIDs). In this study, we investigate both SAPS and DSAIDs that appear during the storm main phase of the 17 March 2015 event through a combination of multi-point observations and numerical simulations. We find that when SAPS/DSAIDs are observed by the DMSP spacecraft near the dusk subauroral region, strong electric fields are detected minutes later by the Van Allen Probes almost in the same conjugate region near the equatorial plane. Numerical simulations are carried out not only to reveal the global context and dynamic evolution of the SAPS in both the magnetospheric and ionospheric systems, but also to aid the understanding of the effect of conductance on the DSAIDs. Our results confirm that SAPS are indeed associated with Region 2 field-aligned currents (FACs) flowing into the low conductance region. On the other hand, the DSAIDs may be related to the double-conductance-trough in the subauroral region.     

Atomic Physics for Atmospheric Composition Measurements

The atomic physics relevant to the interpretation of solar spectra produced by plasmas at temperatures ≳ 105 K are discussed. Methods for determining relative abundance ratios are presented and examples provided from the Coronal Diagnostic Spectrometer on board SOHO. In particular, the Fe/Si ratio in the corona is found to be close to photospheric; the Mg/Ne ratio in the transition region is found to vary by an order of magnitude in different solar features. The Mg/Ne ratios in supergranule cell centres and the network are separated for the first time, although no significant differences are found. This revised version was published online in June 2006 with corrections to the Cover Date.     

机载适航标准DO-178B/C软件开发过程研究

介绍了DO-178B/C标准的发展历程,结合对DO-178B/C标准机载软件生命周期过程的研究,分析了机载软件开发过程需求、设计、编码和集成子过程的关系及输入输出数据,在分析机载软件需求、设计、编码及集成子过程的目标、活动和转换准则的基础上,给出了各子过程的过程模型.展望了DO-178B/C标准的未来研究方向.     

韧性材料的冲蚀损伤数值仿真综述

砂尘造成韧性材料的冲蚀损伤现象和损伤演化规律是冲蚀机理研究的重要内容，基于相应冲蚀试验和数值仿真的分析 方法是揭示冲蚀机理的重要手段。回顾了砂尘冲蚀损伤研究的缘起和发展经历，在介绍砂尘冲蚀损伤机理的基础上，总结了当前 数值仿真研究的3种主流方法：有限元方法、无网格方法和计算流体动力学方法。从数值仿真角度针对砂尘对韧性材料造成的破 坏模式、砂尘冲击姿态、砂尘冲击速度和形状、砂尘破碎对材料去除机制的影响等4个方面综述了影响冲蚀损伤机理的主要因素 和当前研究进展。砂尘对韧性材料造成的破坏模式通常分为材料凹陷、滑动、犁削、切削等4种不同机制；砂尘的冲击姿态决定了 材料的损伤模式；砂尘的冲击速度和砂尘的形状决定了材料的损伤严重程度；砂尘破碎现象对材料的去除机制有一定影响。     

产品设计以三维实体建模为基础，建立单一数据源，实现企业级信息集成——关于进一步推进CAD／CAM技术应用的意见

从总结洪都航空工业集团10年来在普及计算机应用和推进企业数字化信息系统建立方面取得长足进展人笔，论述了该集团公司计算机应用和信息管理工作必须从产品设计三维实体建模数字化抓起。建立单一数据源，实现以产品为对象的企业级信息集成管理。