过氧化氢水溶液在自分解过程中的温升特性研究

针对过氧化氢水溶液在自分解过程中分解放热引起的温升进行传热分析,建立数学模型,求解得出随着浓度、比热容、分解速率以及散热等因素下的温升变化规律。其结果可以为过氧化氢溶液的储存、输送以及推进燃烧控制提供重要的理论依据,为进一步掌握过氧化氢热化学机理提供理论基础。     

The Galactic Environment of the Sun: Interstellar Material Inside and Outside of the Heliosphere

Interstellar material (ISMa) is observed both inside and outside of the heliosphere. Relating these diverse sets of ISMa data provides a richer understanding of both the interstellar medium and the heliosphere. The galactic environment of the Sun is dominated by warm, low-density, partially ionized interstellar material consisting of atoms and dust grains. The properties of the heliosphere are dependent on the pressure, composition, radiation field, ionization, and magnetic field of ambient ISMa. The very low-density interior of the Local Bubble, combined with an expanding superbubble shell associated with star formation in the Scorpius-Centaurus Association, dominate the properties of the local interstellar medium (LISM). Once the heliosphere boundaries and interaction mechanisms are understood, interstellar gas, dust, pickup ions, and anomalous cosmic rays inside of the heliosphere can be directly compared to ISMa outside of the heliosphere. Our understanding of ISMa at the Sun is further enriched when the circumheliospheric interstellar material is compared to observations of other nearby ISMa and the overall context of our galactic environment. The IBEX mission will map the interaction region between the heliosphere and ISMa, and improve the accuracy of comparisons between ISMa inside and outside the heliosphere.     

The Solar Wind Around Pluto (SWAP) Instrument Aboard New Horizons

The Solar Wind Around Pluto (SWAP) instrument on New Horizons will measure the interaction between the solar wind and ions created by atmospheric loss from Pluto. These measurements provide a characterization of the total loss rate and allow us to examine the complex plasma interactions at Pluto for the first time. Constrained to fit within minimal resources, SWAP is optimized to make plasma-ion measurements at all rotation angles as the New Horizons spacecraft scans to image Pluto and Charon during the flyby. To meet these unique requirements, we combined a cylindrically symmetric retarding potential analyzer with small deflectors, a top-hat analyzer, and a redundant/coincidence detection scheme. This configuration allows for highly sensitive measurements and a controllable energy passband at all scan angles of the spacecraft.     

The Search Coil Magnetometer for THEMIS

THEMIS instruments incorporate a tri-axial Search Coil Magnetometer (SCM) designed to measure the magnetic components of waves associated with substorm breakup and expansion. The three search coil antennas cover the same frequency bandwidth, from 0.1 Hz to 4 kHz, in the ULF/ELF frequency range. They extend, with appropriate Noise Equivalent Magnetic Induction (NEMI) and sufficient overlap, the measurements of the fluxgate magnetometers. The NEMI of the searchcoil antennas and associated pre-amplifiers is smaller than 0.76 pT $/\sqrt{\mathrm{Hz}}$ at 10 Hz. The analog signals produced by the searchcoils and associated preamplifiers are digitized and processed inside the Digital Field Box (DFB) and the Instrument Data Processing Unit (IDPU), together with data from the Electric Field Instrument (EFI). Searchcoil telemetry includes waveform transmission, FFT processed data, and data from a filter bank. The frequency range covered depends on the available telemetry. The searchcoils and their three axis structures have been precisely calibrated in a calibration facility, and the calibration of the transfer function is checked on board, usually once per orbit. The tri-axial searchcoils implemented on the five THEMIS spacecraft are working nominally.     

OB Associations, Wolf–Rayet Stars, and the Origin of Galactic Cosmic Rays

We have measured the isotopic abundances of neon and a number of other species in the galactic cosmic rays (GCRs) using the Cosmic Ray Isotope Spectrometer (CRIS) aboard the ACE spacecraft. Our data are compared to recent results from two-component (Wolf–Rayet material plus solar-like mixtures) Wolf–Rayet (WR) models. The three largest deviations of galactic cosmic ray isotope ratios from solar-system ratios predicted by these models, ¹²C/¹⁶O, ²²Ne/²⁰Ne, and ⁵⁸Fe/⁵⁶Fe, are very close to those observed. All of the isotopic ratios that we have measured are consistent with a GCR source consisting of ∼20% of WR material mixed with ∼80% material with solar-system composition. Since WR stars are evolutionary products of OB stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of our data with WR models suggests that OB associations within superbubbles are the likely source of at least a substantial fraction of GCRs. In previous work it has been shown that the primary ⁵⁹Ni (which decays only by electron-capture) in GCRs has decayed, indicating a time interval between nucleosynthesis and acceleration of >10⁵ y. It has been suggested that in the OB association environment, ejecta from supernovae might be accelerated by the high velocity WR winds on a time scale that is short compared to the half-life of ⁵⁹Ni. Thus the ⁵⁹Ni might not have time to decay and this would cast doubt upon the OB association origin of cosmic rays. In this paper we suggest a scenario that should allow much of the ⁵⁹Ni to decay in the OB association environment and conclude that the hypothesis of the OB association origin of cosmic rays appears to be viable.     

A 10 kW DC-DC converter using IGBTs with active snubbers

This full bridge DC-DC converter employs zero voltage switching (ZVS) on one leg and zero current switching (ZCS) on the other. This technique produces exceptionally low insulated-gate bipolar transistor (IGBT) switching losses through the use of an active snubber that recycles energy back to the source. Experimental results are presented for a 10-kW, 20-kHz converter     

HIGH TEMPERATURE MOIRE INTERFEROMETRY TECHNOLOGY

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