Composition of anomalous cosmic rays and implications for the heliosphere

We use energy spectra of anomalous cosmic rays (ACRs) measured with the Cosmic Ray instrument on the Voyager 1 and 2 spacecraft during the period 1994/157-313 to determine several parameters of interest to heliospheric studies. We estimate that the strength of the solar wind termination shock is 2.42 (–0.08, +0.04). We determine the composition of ACRs by estimating their differential energy spectra at the shock and find the following abundance ratios: H/He = 5.6 (–0.5, ⁺0.6), C/He = 0.00048 ± 0.00011, N/He = 0.011 ± 0.001, O/He = 0.075 ± 0.006, and Ne/He = 0.0050 ± 0.0004. We correlate our observations with those of pickup ions to deduce that the long-term ionization rate of neutral nitrogen at 1 AU is 8.3 × 10^–7 s^–1 and that the charge-exchange cross section for neutral N and solar wind protons is 1.0 × 10^–15 cm² at 1.1 keV. We estimate that the neutral C/He ratio in the outer heliosphere is 1.8(–0.7, +0.9) × 10^–5. We also find that heavy ions are preferentially injected into the acceleration process at the termination shock.     

The new radiation belt of the earth from trapped anomalous cosmic rays

In this review we briefly present the observational results on the new radiation belt of the Earth originating from the anomalous cosmic rays (ACR) and their implications. Firstly, a brief historical account of the development of our knowledge and ideas on the trapped particles in the geomagnetic field is presented. We then discuss briefly the first observations of the anomalous cosmic rays inside the magnetosphere in theSkylab experiment in 1973–1974 (Biswaset al., 1975). This showed that the measured ACR oxygen flux was at least 25 times higher than the calculated flux from the interplanetary value, indicating the presence of trapped ACR component originating from the Blake-Freisen mechanism (Biswas and Durgaprasad, 1980). In the Cosmos experiment of the USSR, the presence of trapped ACR oxygen was indicated from the observations of double peaked angular distributution (Grigorovet al., 1990). In the recent satellite experiment, MAST-SAMPEX the new results were obtained which confirmed the earlier indications and established the presence of the trapped ACR component in the geomagnetic field from the spatially separated components of the ACR (Cummingset al., 1993). The properties of the trapped ACR ions as measured in the SAMPEX are briefly discussed. The theoretical model of trapped ACR oxygen by Blake and Preisen are briefly summarised. The implications of the new observations are noted.     

Use of map information for tracking targets on airport surface

A generic and novel approach for integrating airport map information with sensor measurements in the track estimation process is proposed and evaluated. The surface restrictions imposed by the network of roads, taxiways, and runways, represented by a simplified geometric model, are included in both the target observation and the dynamic models, to derive the target state estimates. The performance of the methods proposed is illustrated in representative airport surface scenarios, taking as a reference for comparison other tracking alternatives such as VS-IMM (variable structure interacting multiple model estimator) ground target tracking, or standard ones that do not make use of ground information.     

A robust method for large-scale route optimization on lunar surface utilizing a multi-level map model

As we look ahead to future lunar exploration missions, such as crewed lunar exploration and establishing lunar scientific research stations, the lunar rovers will need to cover vast distances.These distances could range from kilometers to tens of kilometers, and even hundreds and thousands of kilometers. Therefore, it is crucial to develop effective long-range path planning for lunar rovers to meet the demands of lunar patrol exploration. This paper presents a hierarchical map model path planning method that utilizes the existing high-resolution images, digital elevation models and mineral abundance maps. The objective is to address the issue of the construction of lunar rover travel costs in the absence of large-scale, high-resolution digital elevation models. This method models the reference and semantic layers using the middle-and low-resolution remote sensing data. The multi-scale obstacles on the lunar surface are extracted by combining the deep learning algorithm on the high-resolution image, and the obstacle avoidance layer is modeled. A twostage exploratory path planning decision is employed for long-distance driving path planning on a global–local scale. The proposed method analyzes the long-distance accessibility of various areas of scientific significance, such as Rima Bode. A high-precision digital elevation model is created using stereo images to validate the method. Based on the findings, it can be observed that the entire route spans a distance of 930.32 km. The route demonstrates an impressive ability to avoid meterlevel impact craters and linear structures while maintaining an average slope of less than 8°. This paper explores scientific research by traversing at least seven basalt units, uncovering the secrets of lunar volcanic activities, and establishing ‘golden spike' reference points for lunar stratigraphy. The final result of path planning can serve as a valuable reference for the design, mission demonstration,and subsequent project implementation of the new manned lunar rover.     

一种高空台特种调节阀通用特性修正方法

为解决高空模拟试验台建立初期获取的大量试验数据,与基于厂家所提供阀门特性建立的特性模型仿真结果存在较大误差的问题,提出一种基于神经网络和试验数据修正阀门特性的方法。将使用该方法修正得到的新特性代入特性模型进行仿真,并与试验数据进行对比验证。结果表明:相对于特性修正前的仿真结果,修正后的仿真结果最大相对误差绝对值减小47.8%,相对误差绝对值的平均值减小72.6%。     

Aircraft traffic management on the airport surface using VHF datalink for CNS

Aircraft traffic management on the airport surface will require the effective utilization of communications, navigation and surveillance (CNS). This paper describes an experiment which provides a glimpse of future automation. The experiment combines precision surface radar, high-accuracy differential GPS (DGPS) position determination, automatic dependent surveillance (ADS), and ground and airborne automation systems able to intercommunicate via a VHF data link. In particular, this paper describes the air/ground communications provided by the VHF Data Link. Two classes of messages are processed: continual and ad hoc. The former include DGPS corrections, ADS messages and target data. The latter include graphical taxi clearances and hold bar set-reset information. The work described in this paper is the result of a cooperative venture among NASA, Westinghouse-Norden Systems and ARINC     

Electrochemical micromachining of microgroove arrays on phosphor bronze surface for improving the tribological performance

A high friction coefficient and a low wear rate of contacted surfaces are essential elements to friction pairs between the stator and the rotor in ultrasonic motors. It has been shown that surface textures have a significant effect on improving the tribological performance of friction pairs.In this paper, microgroove arrays are introduced to the stator surface for improving the tribological performance of friction pairs between the stator and the rotor in ultrasonic motors. Microgrooves were fabricated on a phosphor bronze surface by through-mask electrochemical micromachining(TMEMM). Parameters, namely, the electrolyte inlet pressure, applied voltage, pulse duty cycle,and frequency, were varied to investigate their influences on the dimensions and morphology of the microgrooves. Results showed that the width and depth of the microgrooves were strongly affected by the applied voltage and frequency, while the morphology of the microgrooves was dependent on the electrolyte inlet pressure and the pulse duty cycle. Compared with a smooth surface, the friction coefficient increased from 0.245 to 0.334 and less abrasion was obtained when a surface was textured with microgrooves of which the width and depth were 185.6 and 57.6 lm,respectively. Microgroove arrays might play an important role in enhancing the performance of ultrasonic motors.     

汽车复合曲面斜截面外形计算方法的研究

提出了一种用于计算汽车车身复合曲面斜截面外形的有效算法。根据实际问题的情况，提出了沿复合曲面三条边界扫描找始点及用自适应步长跟踪求迹的算法。该算法简化了扫描过程，缩短了计算时间，并且所得到的交点记录了坐标值和相应曲面片的参数值。测试显示这种算法简单实用、快速有效，在车身复杂曲面截面质量分析和自由曲面数控加工刀位轨迹计算等方面具有实际应用价值。     

从误差理论到公差设计的延伸

本文介绍了将误差理论中的有关公式拓宽到公差设计中的思路，以及由此而引发的理论再思考。     

Solar Surface Magnetism and Irradiance on Time Scales from Days to the 11-Year Cycle

The uninterrupted measurement of the total solar irradiance during the last three solar cycles and an increasing amount of solar spectral irradiance measurements as well as solar imaging observations (magnetograms and photometric data) have stimulated the development of models attributing irradiance variations to solar surface magnetism. Here we review the current status of solar irradiance measurements and modelling efforts based on solar photospheric magnetic fields. Thereby we restrict ourselves to the study of solar variations from days to the solar cycle. Phenomenological models of the solar atmosphere in combination with imaging observations of solar electromagnetic radiation and measurements of the photospheric magnetic field have reached high enough quality to show that a large fraction (at least, about 80%) of the solar irradiance variability can be explained by the radiative effects of the magnetic activity present in the photosphere. Also, significant progress has been made with magnetohydrodynamic simulations of convection that allow us to relate the radiance of the photospheric magnetic structures to the observations.     

基于试验的高空台混合器至流量管传热模型研究

基于高空台升温试验原理和已有试验数据,对影响升温过程的因素进行了分析,得出混合器出口温度值的高低是影响升温速率的主要因素。同时,采用基于试验数据的建模方法,将经验值转化为数学模型,实现了高空台升温过程的数值模拟。     

Global Response of the Ionosphere to Atmospheric Tides Forced from Below: Recent Progress Based on Satellite Measurements

This paper provides an overview on the recent progress in studying the ionospheric response to atmospheric tides forced from below. The global spatial structure and temporal variability of the atmospheric temperature tides and their ionospheric responses are considered on the basis of modern satellite-board data (COSMIC and TIMED). The tidal waves from the two data sets have been extracted by one and the same data analysis method. The similarity between the lower thermospheric temperature tides and their ionospheric responses provides evidence for confirming the new paradigm of atmosphere-ionosphere coupling. This paper provides also new experimental results which give an explanation why the WN4 and partly WN3 longitude structures are so prominent pattern in the ionosphere. These results present evidence indicating that the WN4 (WN3) structure is not generated only by the DE3 (DE2) tide as it has been often assumed. The DE3 (DE2) tide remains the leading contributor, but the SPW4 and SE2 (SPW3, DW4 and SE1) waves have their effects as well in a way that the ionospheric response becomes almost double (1.5 time stronger). The paper presents also the global distribution and temporal variability of the sun-synchronous 24-h (DW1), 12-h (SW2) and 8-h (TW3) electron density oscillations. It has been shown that while the latitude and altitude structure of the ionospheric SW2 response is predominantly shaped by the migrating SW2 tide forced from below the DW1 response is mainly due to daily variability of the photo-ionization. The peculiar vertical structure of the ionospheric TW3 response, that shows downward/upward phase progression, calls for further study of the physical processes shaping this ionospheric response.     

浅谈波音737NG飞机eFLOW构型活门非指令关断的监控方式

介绍了波音737NG飞机空调eFLOW构型系统的原理,对机队具体的故障进行了分析,在借鉴厂家建议的基础上,基于公司自有的监控平台创造性地探索出新的监控方式和算法,为国内同行处理此类问题提供了一种可供借鉴的方法。     

带源项的守恒系统时间分裂算法定常解的收敛性研究

时间分裂算法很难获得带源项的守恒系统的定常解,本文中,考虑使用基本的隐式方法积分线性、二次和三次源项,研究了时间分裂算法不能收敛到数值定常态的原因.采用一个刚性参数的方式预测定常态的误差,刚性参数依赖于特定的源项.当源项是解的线性函数时,不存在定常态误差;当源项是解的非线形函数时,发现定常状态的误差是刚性参数的单调增加函数.定常态误差的分析将推广到标准k-epsilon双方程湍流模型计算的情况.     

Estimations of the Seismic Pressure Noise on Mars Determined from Large Eddy Simulations and Demonstration of Pressure Decorrelation Techniques for the Insight Mission

The atmospheric pressure fluctuations on Mars induce an elastic response in the ground that creates a ground tilt, detectable as a seismic signal on the InSight seismometer SEIS. The seismic pressure noise is modeled using Large Eddy Simulations (LES) of the wind and surface pressure at the InSight landing site and a Green’s function ground deformation approach that is subsequently validated via a detailed comparison with two other methods: a spectral approach, and an approach based on Sorrells’ theory (Sorrells, Geophys. J. Int. 26:71–82, 1971; Sorrells et al., Nat. Phys. Sci. 229:14–16, 1971). The horizontal accelerations as a result of the ground tilt due to the LES turbulence-induced pressure fluctuations are found to be typically \(\sim 2 \mbox{--} 40~\mbox{nm}/\mbox{s}^{2}\) in amplitude, whereas the direct horizontal acceleration is two orders of magnitude smaller and is thus negligible in comparison. The vertical accelerations are found to be \(\sim 0.1\mbox{--}6~\mbox{nm}/\mbox{s}^{2}\) in amplitude. These are expected to be worst-case estimates for the seismic noise as we use a half-space approximation; the presence at some (shallow) depth of a harder layer would significantly reduce quasi-static displacement and tilt effects.We show that under calm conditions, a single-pressure measurement is representative of the large-scale pressure field (to a distance of several kilometers), particularly in the prevailing wind direction. However, during windy conditions, small-scale turbulence results in a reduced correlation between the pressure signals, and the single-pressure measurement becomes less representative of the pressure field. The correlation between the seismic signal and the pressure signal is found to be higher for the windiest period because the seismic pressure noise reflects the atmospheric structure close to the seismometer.In the same way that we reduce the atmospheric seismic signal by making use of a pressure sensor that is part of the InSight Auxiliary Payload Sensor Suite, we also the use the synthetic noise data obtained from the LES pressure field to demonstrate a decorrelation strategy. We show that our decorrelation approach is efficient, resulting in a reduction by a factor of \(\sim 5\) in the observed horizontal tilt noise (in the wind direction) and the vertical noise. This technique can, therefore, be used to remove the pressure signal from the seismic data obtained on Mars during the InSight mission.