原位合成Al2O3/Ti-Al复合材料的研究

利用氧对金属Ti、Al粉的部分氧化，原位合成了Al2O3／Ti-Al复合材料，通过XRD和SEM手段，发现Al2O3分布在Ti—Al基体交界处，在一些制得的复合材料中出现了大量原位生成的纤维。借助差热分析，对该制备过程的反应机理进行了初步探讨，研究认为该制备过程的反应步骤为：Ti、Al金属粉表面氧化→铝的熔化→TiAl，的生成→Ti2Al、TiAl、Ti，Al等多种化合物生成和Al对TiO2的还原反应。原始组成中铝含量决定了复合材料的主要晶相组成，铝含量不足时，生成Ti2Al、TiAl、Ti3Al等多种金属间化合物和氧化铝；铝含量足够时，最终的产物为TiAl3、金属铝以及氧化铝等相。     

An Improved Algorithm for Adaptive Processing

The Widrow-Hoff least mean square (LMS) algorithm based on the method of steepest descent is conditionally stable. A modified algorithm is given which is unconditionally stable, capable of better performance when used in adaptive filter processing, and provides a more realistic means for simulating the Applebaum-Howells adaptive loop.     

Gender differences in leader and follower perceptions of social support in Antarctica

The purpose of this study was to methodologically explore the links among social support, gender, age, prior experience, leader/follower status, and leadership effectiveness noted in previous accounts from Antarctic stations. Data for this study were collected from volunteers involved in Australian National Antarctic Research Expeditions conducted from 1996 to 2001. Multilevel analysis revealed that most of the variance in perceptions of social support was at the individual level (71%). Perceptions of social support had less variance at the group level (29%) and little variance at the weekly level. At the group level, the explanatory variables we examined included leadership effectiveness, gender similarity, and age similarity. At the individual level, the explanatory variables we examined included age, gender, prior experience, and leader/follower status. An interaction between gender and leader/follower status contributed to a significant model of variation in perceptions of social support.     

Voyager 2 plasma wave observations at Uranus

At Uranus, the Voyager 2 plasma wave investigation observed very significant phenomena related to radio emissions, dust impacts and magnetospheric wave-particle interactions. On January 19, 1986 (R= 270R_U) the plasma wave investigation detected an intense radio burst at 31 and 56 kHz, and this provided the first indication that Uranus had a magnetosphere. During the encounter we observed more of these sporadic bursts, along with relatively continuous radio emissions extending down to 10 kHz, and a sporadic narrowband radio signal with f near 5 kHz. As Voyager passed through the ring plane, the plasma wave investigation recorded a large number of dust impacts. The dust ring was relatively diffuse (thickness of several thousand kilometers) and the peak impact rate was near 50 hits/second. The Voyager 2 plasma wave instrument also detected many strong electromagnetic and electrostatic plasma waves, with intensity peaks in the region within 12 Uranus adii. These waves have characteristics that can interact strongly with the local plasma and with the trapped energetic particles, leading to precipitation into the atmosphere, charged particle acceleration, and charged particle diffusion. In addition we detected strong wave activity in the region of the bow shock and moderate levels in the magnetic tail.     

The Balloon Array for RBSP Relativistic Electron Losses (BARREL)

BARREL is a multiple-balloon investigation designed to study electron losses from Earth’s Radiation Belts. Selected as a NASA Living with a Star Mission of Opportunity, BARREL augments the Radiation Belt Storm Probes mission by providing measurements of relativistic electron precipitation with a pair of Antarctic balloon campaigns that will be conducted during the Austral summers (January-February) of 2013 and 2014. During each campaign, a total of 20 small (～20 kg) stratospheric balloons will be successively launched to maintain an array of ～5 payloads spread across ～6 hours of magnetic local time in the region that magnetically maps to the radiation belts. Each balloon carries an X-ray spectrometer to measure the bremsstrahlung X-rays produced by precipitating relativistic electrons as they collide with neutrals in the atmosphere, and a DC magnetometer to measure ULF-timescale variations of the magnetic field. BARREL will provide the first balloon measurements of relativistic electron precipitation while comprehensive in situ measurements of both plasma waves and energetic particles are available, and will characterize the spatial scale of precipitation at relativistic energies. All data and analysis software will be made freely available to the scientific community.     

A synthetic aviation hydraulic fluid of new generation

The results of investigating a domestic synthetic hydraulic fluid of new generation are presented. By comparing with the existing domestic and foreign analogues, we specify the main advantages and disadvantages of this hydraulic fluid.     

On the concept of a future carrier-based light fighter

The peculiarities of future light fighter concept generation, reflecting tendencies of fighter aviation development and potentialities of scientific and research background are considered.     

Direct comparison of transient radiation belt topology and dynamics in 1991 based on measurements onboard Mir space station and NOAA satellite.

In March 1991 the CRRES spacecraft measured a new transient radiation belt resulting from a solar proton event and subsequent geomagnetic disturbance. The presence of this belt was also noted by dosimeter-radiometers aboard the Mir space station (approx. 400 km, 51 degrees orbit) and by particle telescopes on the NOAA-10 spacecraft (850 km, 98 degrees). This event provides a unique opportunity to compare particle flux and dose measurements made by different instruments in different orbits under changing conditions. We present here a comparison of the measurements made by the different detectors. We discuss the topology and dynamics of the transient radiation belt over a period of more than one year.     

Verification of a mathematical model of dynamic loading in the quasistatic statement for a helicopter tubular skid landing gear by the results of drop tests

We present the results of verifying a mathematical model of dynamic loading of the helicopter skid landing gear with regard for two successive landing impacts. Also presented are the results of analyzing the interaction of springs in the course of drop tests.