The Time-of-Flight Energy,Angle, Mass Spectrograph (Teams) Experiment for Fast

The Time-of-flight Energy Angle Mass Spectrograph (TEAMS) is being flown on the FAST Small Explorer mission to measure the 3-dimensional distribution function of the major ion species present in the lower magnetosphere. The instrument is similar to time-of-flight plasma analyzer systems that have been designed and planned for flight as CODIF (COmposition and DIstribution Function analyzer) on the four European Space Agency Cluster-II spacecraft and, as ESIC (Equator-S Ion Composition instrument) on Equator-S. This instrument allows the 3-dimensional distribution functions of individual ion species to be determined within spin period (2.5 s). Two-dimensional distributions are measured in 80 ms. These capabilities are crucial for the study of selective energization processes in the auroral regions of the magnetosphere. The design, operational characteristics, and test and calibration results for this instrument are presented. The sensor consists of a toroidal top-hat electrostatic analyzer with instantaneous acceptance of ions over 360° in polar angle. After post-acceleration of the incoming ions by up to 25 kV, a time-of-flight mass spectrograph discriminates the individual species. It has been demonstrated through calibration that the instrument can easily separate H⁺, He²⁺, He⁺, O⁺ and, for energies after post-acceleration of > 20 keV, even O₂ ⁺ molecules. On-board mass discrimination and the internal accumulation of several distinct data quantities combined with the spacecraft's flexible telemetry formatting allow for instrument data rates from 7.8 kb s^–1 to 315 kb s^–1 to be telemetered to ground through the FAST centralized Instrument Data Processor.     

Physiologic and metabolic responses of wheat seedlings to elevated and super-elevated carbon dioxide

The metabolic consequence of suboptimal (400 μmol mol⁻¹ or ppm), near-optimal (1500 ppm) and supra-optimal (10,000 ppm) atmospheric carbon dioxide concentrations [CO₂] was investigated in an attempt to reveal plausible underlying mechanisms for the differential physiological and developmental responses to increasing [CO₂]. Both non-targeted and targeted metabolite profiling by GC–MS and LC–MS were employed to examine primary and secondary metabolites in wheat (Triticum aestivum, cv Yocoro rojo) continuously exposed to these [CO₂] levels for 14, 21 and 28 days. Metabolite profile was altered by both [CO₂] and physiological age. In general, plants grown under high [CO₂] exhibited a metabolite profile characteristic of older plants under ambient CO₂. Elevated [CO₂] resulted in higher levels of phosphorylated sugar intermediates, though no clear trend in the content of reducing sugars was observed. Transient starch content was enhanced by increasing [CO₂] to a much greater extent at 10,000 ppm CO₂ than at 1500 ppm CO₂. The percentage increase of starch content resulting from CO₂ enrichment declined as plants develope. In contrast, elevated [CO₂] promoted the accumulation of secondary metabolites (flavonoids) progressively to a greater extent as plants became mature. Elevated [CO₂] to 1500 ppm induced a higher initial growth rate, while super-elevated [CO₂] appeared to negate such initial growth promotion. However, after 4 weeks, there was no difference in vegetative growth between 1500 and 10,000 ppm CO₂-grown plants, both elevated CO₂ levels resulted in an overall 25% increase in biomass over the control plants. More interestingly, elevated atmospheric [CO₂] reduced evapotranspiration rate (ET), but further increase to the supra-optimal level resulted in increased ET (a reversed trend), i.e. ET at 1500 ppm < ET at 10,000 ppm < ET at 400 ppm. The differential effect of elevated and super-elevated CO₂ on plants was further reflected in the nitrogen dynamics. These results provide the potential metabolic basis for the differential productivity and stomatal function of plants grown under elevated and super-elevated CO₂ levels.     

Induced Magnetic Fields in Solar System Bodies

Electromagnetic induction is a powerful technique to study the electrical conductivity of the interior of the Earth and other solar system bodies. Information about the electrical conductivity structure can provide strong constraints on the associated internal composition of planetary bodies. Here we give a review of the basic principles of the electromagnetic induction technique and discuss its application to various bodies of our solar system. We also show that the plasma environment, in which the bodies are embedded, generates in addition to the induced magnetic fields competing plasma magnetic fields. These fields need to be treated appropriately to reliably interpret magnetic field measurements in the vicinity of solar system bodies. Induction measurements are particularly important in the search for liquid water outside of Earth. Magnetic field measurements by the Galileo spacecraft provide strong evidence for a subsurface ocean on Europa and Callisto. The induction technique will provide additional important constraints on the possible subsurface water, when used on future Europa and Ganymede orbiters. It can also be applied to probe Enceladus and Titan with Cassini and future spacecraft.     

A uniform anthropomorphological approach to the human conception of dimensional relations

Within psycholinguistics, the dimensional conception of space is described through a variety of theoretical constructs, e.g., frames of reference, perspectives, strategies, and patterns. The objective of this paper is to introduce a uniform classification of the alternatives of dimensionally conceiving of object relations, derived from the functional and morphological asymmetries of the human body which define an anthropomorphous Origo, and from our ability to mentally project the Origo into positions and orientations other than we actually occupy. Particularly, the conception of dimensional relations on the first horizontal line is explained through the principle of perceptual accessibility of objects; this allows for the uniform treatment of (almost) all conceptual alternatives from basic psychological principles. Finally, some implications of this anthropomorphological view for the human cognition of dimensional relations are discussed and underpinned with empirical results.     

The low-energy neutral atom imager for IMAGE

The `Imager for Magnetosphere-to-Aurora Global Exploration (IMAGE) will be launched early in the year 2000. It will be the first mission dedicated to imaging, with the capability to determine how the magnetosphere changes globally in response to solar storm effects in the solar wind, on time scales as short as a few minutes. The low energy neutral atom (LENA) imager uses a new atom-to-negative ion surface conversion technology to image the neutral atom flux and measure its composition (H and O) and energy distribution (10 to 750 eV). LENA uses electrostatic optics techniques for energy (per charge) discrimination and carbon foil time-of-flight techniques for mass discrimination. It has a 90°×° field-of-view in 12 pixels, each nominally 8°×°. Spacecraft spin provides a total field-of-view of 90°×360°, comprised of 12×45 pixels. LENA is designed to image fast neutral atom fluxes in its energy range, emitted by auroral ionospheres or the sun, or penetrating from the interstellar medium. It will thereby determine how superthermal plasma heating is distributed in space, how and why it varies on short time scales, and how this heating is driven by solar activity as reflected in solar wind conditions.     

The morphology of fair weather cumulus cloud fields as remotely-sensed from satellites and some applications

The morphology of fair weather Cumulus cloud field over several ocean areas distributed globally has been studied using LANDSAT data. Distribution functions of cloud size, spacing, perimeter and other relevant parameters have been derived, as well as their correlations and moments.Examples of distribution functions of cloud size, cloud spacing and fractal dimension of the cloud fields over oceanic areas are given and applied to several problem in Cu convection.     

固化过程可视化:采用集成的超声传感器监测交联反应过程

在工艺过程中,树脂的反应程度或固化度通常因为其不会导致可见的缺陷,所以常被忽视.然而,未完全固化的产品会对最终的力学性能产生很大的影响,在使用过程中伴随有较大温度变化的情况下尤其如此.