The γ-ray bursts as a result of the proper activity of the neutron star

The model of the Γ-ray burst is developed which is based on the nuclear explosion in the neutron star envelope because of the chain fission reaction of the superheavy nuclei. It is shown, that the main part of the Γ-ray burst radiation must have thermal origin, but the nonthermal component and Γ-ray lines may be present. The parameters of the strong burst of 5 March 1979 are evaluated on the basis of its radiation spectra and the present model. The distance to this burst is about 100 pc and the total energy of this Γ-ray burst is about 2.1039 ergs.     

A Far Infrared Photometer (FIRP) for the Infrared Telescope in Space (IRTS)

We describe the design and calibration of the Far-Infrared Photometer (FIRP), one of four focal plane instruments on the Infrared Telescope in Space (IRTS). The FIRP will provide absolute photometry in four bands centered at 150, 250, 400, and 700 μm with spectral resolution λ/Δλ ≈ 3 and spatial resolution ΔΘ = 0.5 degrees. High sensitivity is achieved by using bolometric detectors operated at 300 mK in an AC bridge circuit. The closed-cycle ³He refrigerator can be recycled in orbit. A 2 K shutter provides a zero reference for each field of view. More than 10% of the sky will be surveyed during the ≈3 week mission lifetime with a sensitivity of <10⁻¹³ W·cm⁻²·sr⁻¹ per 0.5 degree pixel.     

The Freja wave and plasma density experiment

The Wave Experiment, F4, on the Swedish/German satelliteFreja, is designed to measure the electric wave fields up to 4 MHz, the magnetic wave fields up to 16 kHz and the plasma density and its relative variations up to 2 kHz. Six wave signals and four density probe signals can be measured simultaneously. The wave forms of all signals are transmitted to ground without any analysis onboard. The limited TM allocation does not allow continuous sampling of the wave signals, so normally the measurements are made in snapshots of various lengths dependent on sampling frequency, etc. Continuous sampling can be made for shorter time periods by using a 6 Mbyte memory as a buffer.     

Integrated Planning and Execution for Autonomous Spacecraft

An autonomous spacecraft must balance long-term and short-term considerations. It must perform purposeful activities that ensure long-term science and engineering goals are achieved and ensure that it maintains positive resource margins. This requires planning in advance to avoid a series of shortsighted decisions that can lead to failure. However, it must also respond in a timely fashion to a somewhat dynamic and unpredictable environment. Thus, in terms of high-level, goal-oriented activity, spacecraft plans must often be modified due to fortuitous events such as early completion of observations and setbacks such as failure to acquire a guidestar for a science observation. This describes an integrated planning and execution architecture that supports continuous modification and updating of a current working plan in light of a changing operating context.     

Ureilites

Ureilites are a rare group of five stony meteorites — feldsparless achondrites containing diamonds of preterrestrial origin the total weight of them being 315 carats. The whole carbon content in ureilites makes up 1.5–4.1%. Ureilites substantially differ from the other stony meteorites. In comparison with chondrites they are enriched in Mg but depleted in metal, troilite, alkaline elements. All ureilites are very similar by their structure. They contain elongated cavities generally stretched in the same direction. The structure of ureilites is an achondritic porphyric one. These meteorites consist of large olivine grains, there is less clinopyroxene (pigeonite). They contain kamacite (Ni content being 1.5–4%), troilite FeS, chromite. Carbon material is represented by diamond, graphite and organic material being present in a disequilibrium state. Two ureilites (North Haig and Dingo Pup Donga) were considerably oxidized during terrestrial weathering and contain secondary iron oxides.Diamonds are present in ureilites in thin intergrowths with graphite being disposed between silicate grains more or less evenly in the meteorite. The sizes of such black diamond-graphite aggregates are 0.3–0.9 mm. The sizes of the micromonocrystals of diamond and graphite are less than 1. The diamond-graphite aggregates contain dispersed particles of kamacite, troilite, chromite, nickelchrome, being present in very thin intergrowths with one another. Besides the usual diamond there is an admixture of lonsdaleite in the aggregates representing a hexagonal diamond with a würtzite-like structure. Lonsdaleite has been identified in the ureilites Novo Urei, Goalpara, North Haig. The diamonds of ureilites are characterized by inhomogeneities in the crystalline structure which are at least partly caused by the presence of donor nitrogen. According to the isotopic carbon composition the diamond in the meteorite Novo Urei has the value C¹³ = -5.7.The structure peculiarities of ureilites bear witness of the fact that these meteorites had been subject to the action of dynamic pressure about 300–600 kbar. The impact had taken place in cosmic space. All ureilites subdivide into two types: the first type are Novo Urei, Dyalpur, Dingo Pup Donga, the second type are Goalpara, North Haig according to the following signs: (1) olivine grains are finer in ureilites of the second type; (2) twinning is more typical of clinopyroxenes of ureilites belonging to the first type; (3) in ureilites of the first type a net-like iron distribution is observed, in ureilites of the second type kamacite plates are chiefly present between silicate grains; (4) the size of diamondgraphite intergrowths in ureilites of the first type does not exceed 0.3 mm, in ureilites of the second type it reaches 0.9 mm. Ureilites of the first type have undergone a less intensive impact than ureilites of the second type. Certain similarity of the material composition of ureilites and of the material composition of carbonaceous chondrites, the distinction of these two groups of meteorites from all other meteorites bear witness of the fact that ureilites have formed from carbonaceous chondrites during a collision of asteroid bodies in cosmic space, diamonds having been formed from the carbon material of carbonaceous chondrites.     

基于自联想网络的发动机传感器解析余度技术

本文提出了一种基于自联想神经网络的传感器解析余度技术。在这种网络中,冗余传感器的信息被压缩、重组进入网络的第一部分,网络的第二部分将压缩信息恢复出来。基于数据融合原理,若一个传感器发生故障,其它传感器仍可提供足够的信息代替发生故障的传感器。理论分析和用于涡轴发动机的仿真结果表明,这种特殊结构的自联想网络具有良好的过滤噪声和故障信号的作用,特别适合于用作不易建模的复杂对象的传感器信号重构     

The Genesis Solar-Wind Collector Materials

Genesis (NASA Discovery Mission #5) is a sample return mission. Collectors comprised of ultra-high purity materials will be exposed to the solar wind and then returned to Earth for laboratory analysis. There is a suite of fifteen types of ultra-pure materials distributed among several locations. Most of the materials are mounted on deployable panels (‘collector arrays’), with some as targets in the focal spot of an electrostatic mirror (the ‘concentrator’). Other materials are strategically placed on the spacecraft as additional targets of opportunity to maximize the area for solar-wind collection. Most of the collection area consists of hexagonal collectors in the arrays; approximately half are silicon, the rest are for solar-wind components not retained and/or not easily measured in silicon. There are a variety of materials both in collector arrays and elsewhere targeted for the analyses of specific solar-wind components. Engineering and science factors drove the selection process. Engineering required testing of physical properties such as the ability to withstand shaking on launch and thermal cycling during deployment. Science constraints included bulk purity, surface and interface cleanliness, retentiveness with respect to individual solar-wind components, and availability. A detailed report of material parameters planned as a resource for choosing materials for study will be published on a Genesis website, and will be updated as additional information is obtained. Some material is already linked to the Genesis plasma data website (genesis.lanl.gov). Genesis should provide a reservoir of materials for allocation to the scientific community throughout the 21st Century. This revised version was published online in August 2006 with corrections to the Cover Date.