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1.
The fluxgate magnetometer experiment onboard the ROSETTA spacecraft aims to measure the magnetic field in the interaction region of the solar wind plasma with comet 67P/Churyumov-Gerasimenko. It consists of a system of two ultra light (about 28 g each ) triaxial fluxgate magnetometer sensors, mounted on the 1.5 m long spacecraft boom. The measurement range of each sensor is ±16384 nT with quantization steps of 31 pT. The magnetometer sensors are operated with a time resolution of up to 0.05 s, corresponding to a bandwidth of 0–10 Hz. This performance of the RPC-MAG sensors allows detailed analyses of magnetic field variations in the cometary environment. RPC-MAG furthermore is designed to study possible remnant magnetic fields of the nucleus, measurements which will be done in close cooperation with the ROSETTA lander magnetometer experiment ROMAP.  相似文献   
2.
This discusses the implementation issues of installing a commercially available hand geometry system in the current infrastructure of Purdue University's Recreational Sports Center. In addition to a performance analysis of the system, a pre- and post-data collection survey was distributed to the 129 test subjects gathering information on perceptions of biometrics, in particular hand geometry, as well as participants' thoughts and feelings during their interaction with the hand geometry device. The results of the survey suggest that participants were accepting of hand geometry. Additionally, analyses of the participants' survey responses revealed that 93% liked using hand geometry, 98% thought it was easy to use, and 87% preferred it to the existing card-based system, while nobody thought the device invaded their personal privacy. System performance achieved a 3-try match rate of 99.02% (FRR 0.98%) when "gaming"/potential impostor attempts were removed from analysis. The failure to enroll rate was zero. Statistical analyses exposed a significant difference in the scores of attempts made by users with prior hand geometry usage, and subjects that could not straighten out their hand on the device. However, there were no statistical difference in the effects of rings/no rings, improper hand placements/proper hand placements, or gender on hand geometry score.  相似文献   
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As the title suggests, the purpose of this chapter is to review the current status of numerical simulations of black hole accretion disks. This chapter focuses exclusively on global simulations of the accretion process within a few tens of gravitational radii of the black hole. Most of the simulations discussed are performed using general relativistic magnetohydrodynamic (MHD) schemes, although some mention is made of Newtonian radiation MHD simulations and smoothed particle hydrodynamics. The goal is to convey some of the exciting work that has been going on in the past few years and provide some speculation on future directions.  相似文献   
5.
The Solar Dynamo     
Observations relevant to current models of the solar dynamo are presented, with emphasis on the history of solar magnetic activity and on the location and nature of the solar tachocline. The problems encountered when direct numerical simulation is used to analyse the solar cycle are discussed, and recent progress is reviewed. Mean field dynamo theory is still the basis of most theories of the solar dynamo, so a discussion of its fundamental principles and its underlying assumptions is given. The role of magnetic helicity is discussed. Some of the most popular models based on mean field theory are reviewed briefly. Dynamo models based on severe truncations of the full MHD equations are discussed.  相似文献   
6.
采用多学科专业CAE工具LMS Virtual.Lab和LMS Imagine.Lab AMESim设计前缘缝翼,这不仅展示了不同物理领域的集成,还包括采用LMS Imagine.Lab AMESim构建的一维或称"集总参数"模型与采用LMS Virtual.Lab构建的三维模型的集成。  相似文献   
7.
The LIPS III satellite, which was launched into a 1100-km circular orbit of 60° inclination in the spring of 1987, is discussed. LIPS III is a member of the living-plume-shield class of spacecraft, all of which were built around a simple sheet metal plume deflector. The purpose of LIPS III was to provide a testbed for space power sources. An overview of the LIPS III system is given, and the experiments submitted for it, all but one of which were photovoltaic in nature, are described  相似文献   
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Over the last 3 years, a team at JPL has worked to design a new concept for a small, low cost lander applicable to a variety of in-situ lunar exploration activities. This concept, named Lunette, originated as a design which would exploit potential excess capacity of EELV launches by being compatible with the EELV Secondary Payload Adapter (ESPA). The original Lunette mission concept would have allowed up to six low cost landers to be delivered to a targeted region of the moon, with landings separated by a few km, allowing establishment of a regional network with a single, shared launch. The original concept faced limits in the extent of regional distribution of landing sites since all six landers were dependent on a single solid rocket braking motor. In the last year the Lunette team has focused on a modification of the original ESPA-based concept to a design that would allow launch of multiple individual landers (each with its own braking stage) on a single launch vehicle, where each lander would be capable of independent targeting and landing. With such an implementation, the entire lunar surface could be accessed for establishment of network nodes that could enable high priority geophysical measurements on a scale not seen since Apollo. The present paper discusses the current state of the design of the Lunette geophysical network lander, as well as describing mission design, science operations, and an innovative design solution allowing the lander to take critical data continuously, even over the lunar night, without the need for radioisotope power systems.  相似文献   
10.
The central objective of the New Horizons prime mission was to make the first exploration of Pluto and its system of moons. Following that, New Horizons has been approved for its first extended mission, which has the objectives of extensively studying the Kuiper Belt environment, observing numerous Kuiper Belt Objects (KBOs) and Centaurs in unique ways, and making the first close flyby of the KBO 486958 2014 MU69. This review summarizes the objectives and plans for this approved mission extension, and briefly looks forward to potential objectives for subsequent extended missions by New Horizons.  相似文献   
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