MMW radar scattering statistics of terrain at near grazingincidence

The statistical behavior of clutter observed near grazing incidence and at 95 GHz is investigated for the specific cases of bare ground, snow cover, and for a heterogeneous scene. The bare ground constitutes a homogeneous target under homogeneous conditions and the magnitude of the amplitude is Rayleigh distributed. While the snow cover is a homogeneous target, the conditions under which it was observed are heterogeneous, and the Bayes rule is employed to describe its clutter distribution. The Bayes rule integrates variations due to signal fading with the underlying variations in the backscattering coefficient associated with the heterogeneity. The heterogeneous scene is also successfully described with the Bayes rule     

Postural control responses sitting on unstable board during visual stimulation.

Concerning with the relation of vection induced by the optokinetic stimulation and the body movement, especially we attended to the neck joint movement, which counteracted to the shoulder movement. Then, we analyzed the mechanisms of the sitting postural control by using the seesaw board. By the optokinetic stimulation through the head mounted display (H.M.D.), the vection was leaded, and it affected to the sway of the body on the seesaw board. In this experiment, we found that the movement of upper part of body except for the head was the same direction to the seesaw board but the head moved out of phase to the seesaw board. This phenomenon will be suggested that the unstable condition of sway is balanced by the counter swing of head and the neck muscle tonus is controlled by acting of the vestibulo-collic reflex.     

Physiological effects of acute and ordinary bed rest conditions on endurance trained volunteers.

The aim of this study was to carry out a comparative study of water balance and water protein composition of the blood during exposure to acute (abrupt restriction of motor activity) and ordinary rigorous bed rest of 7 days. The studies were performed on 30 long distance runners aged 22-25 years old who had a VO2, max of 66 ml kg-1 min-1 on the average. The volunteers were divided into three equal groups: the volunteers in the 1st group were under a normal ambulatory life conditions (control subjects), the volunteers of the 2nd group subjected to an acute bed rest (abrupt restriction of motor activity) regime (acute bed rested subjects) and the volunteers of the 3rd group were submitted to ordinary and rigorous bed rest (rigorous bed rested subjects). All volunteers were on an average of 13.8 km day before taking part in this investigation. The 2nd and 3rd groups of volunteers were kept under a rigorous bed rest regime for 7 days. During the prebed rest period and actual bed rest period plasma volume (PV), total protein and protein fractions (albumins and globulins) and hematocrit were measured. Exposure to acute bed rest conditions induced a significant increase in hematocrit, hemoglobin concentration, protein fractions and marked decrease in (PV) and water balance which were significantly more pronounced than during exposure to ordinary rigorous bed rest. It was concluded that exposure to acute bed rest conditions induces significantly greater changes in water balance and water protein concentration of the blood of endurance trained volunteers than exposure to ordinary rigorous bed rest conditions.     

Points of controversy in the study of magnetic storms

In the present review we concentrate on the most important and so far unresolved problems concerning morphology and physics of magnetic storms, namely, 1) which currents are responsible for the Dst variation; 2) which geophysical factors control the Dst index and what the underlying physics is; 3) why the latitude of the auroral electrojets and energetic particle precipitation region decreases during storms; 4) if there actually is a storm-to-substorm relation. We present major experimental results and theoretical views on each of the above problems.     

Digital beam forming (DBF) antenna system for mobile communications

We demonstrate the feasibility of a digital beam forming (DBF) and beam space CMA (Constant Modulus Algorithm) adaptive array antenna by implementing a digital signal processor (DSP) in ASICs using field programmable gate arrays (FPGA), this DBF can synthesize 16 multi-beams and eliminate interference signals by CMA adaptive processing. The whole function was implemented in 10 DSPs about 127,000 equivalent gates. Simple experimental results have confirmed the basic function of the DBF and BSCMA adaptive array antenna     

Novel AC-DC and DC-DC converters with a diode-capacitor multiplier

This paper presents a transformerless ac-dc and or dc-dc converter with a high output voltage multiplicity, which contains only one switch. The converter consists of an inverter and a diode-capacitor multiplier (DCM) and provides a voltage gain equal to double the number of multiplier steps. In the case of ac-dc conversion the proposed converter offers a practically unit power factor and provides a sine wave input current. The analysis of the steady state as well as the transient behavior of the DCM is given and simplified equivalent circuits are proposed. The prototype of the DCM has been built and tested to show the validity of the proposed converter. The theoretical analysis, the computer simulation results, and the experimental testing results are in good agreement.     

Development of thin-foil substrates for a large X-ray telescope

We have built a prototype of thin-foil substrates for the future mission with a large X-ray telescope. In future X-ray missions, the understanding of the early universe to reveal the evolution of the universe will become an important issue. For this purpose, large telescopes with high-spatial resolution up to 10^′′ are required. Using a stamping die with high accuracy, we have successfully press-formed thin-foil substrates into an almost accurate form of the Wolter type-I optics, which reflect X-rays twice with their confocal paraboloidal and hyperboloidal reflectors. The accuracy of the shape has reached to <15 μm.     

Optical fiber geostationary tether satellite (F-GTS) system design

The geostationary satellite orbit (GSO) is a limited natural resource and its efficient utilization is very important. The geostationary tether satellite (GTS) system has a number of satellites aligned along the local vertical on either side of the nominal geostationary position. The system is synchronized with the Earth's rotation and all the various altitudes are geostationary, Furthermore, optical-fiber geostationary tether satellite (F-GTS) system has been introduced to improve the GTS system, with regard to increment of communication capacity, simplification of interference paths and intersatellite link (ISL) capability. The F-GTS system design is discussed with the purpose of achieving a realistic satellite network. Three frequency bands, i.e., the 14/11, 30/20, and 50/40 GHz bands, are examined for selection of the optimum frequency band. The F-GTS system example for covering the service areas in Japan is discussed with regard to satellite antenna diameter, communication capacities, etc. To apply the F-GTS system to the whole GSO, the diagonal azimuth orbit arrangement method is proposed for low latitude service areas. Moreover, the F-GTS communication capacity and total communication capacity, when the F-GTS systems are applied to the whole GSO, are also examined.     

采样量化与滤波对圆锥补偿算法影响对比分析

研究了圆锥运动情况下陀螺角增量采样量化对姿态误差的影响, 对比分析 了单子样算法、三子样扩展频率级数算法和三子样显式频率整形算法,理论推导给出陀 螺角增量分辨率造成的量化误差方差和圆锥算法姿态误差方差间关系的理论表达式。推 导公式及蒙特卡罗仿真结果表明,除通过脉冲细分提高陀螺角增量分辨率外,低通滤波 和提高姿态更新频率也可减小量化误差对姿态解算的误差影响。     

Updated TUS space fluorescence detector for study of UHECR

The TUS (Tracking Ultra-violet Set up) space fluorescence detector has to be launched in 2010 as a separated platform in Foton (Bion) mission prepared by the Samara enterprise. This detector was designed for another satellite and the updated variant of the TUS detector for a new platform is presented. The data on UV glow of the atmosphere obtained in operation of one pixel of the TUS detector on board the Moscow State University “Universitetsky-Tatiana” satellite was taken into account in design of the updated TUS detector. The data on UV transient flashes registered in “Universitetsky-Tatiana” mission are of special interest. Electronics of the TUS detector able to select and register different types of UV events in the atmosphere is presented.