An empirical model of electron density for low and middle latitudes below 200 km

Our empirical model of electron density (n_e) for quiet and weakly disturbed geomagnetic conditions (Kp not greater 4) takes account of comparative analysis of existing models and of experimental data obtained by rockets and incoherent scatter radar. The model describes the n_e distribution in the 80 to 200 km height range at low and middle latitudes, and to some extent, in the subauroral region. It is presented in analytical form thus allowing one to calculate electron density profiles for any time. The electron density distribution at 140 km depends on the season (day of the year) and on the solar zenith angle. Profile variations during the day are for one season shown. Different from other models, ours specifies the variations during sunrise and sunset and reflects the particular profile shape at night admitting the occurrence of an intermediate layer.     

一种Ka频段宽带3dB功分桥的实现技术研究

文章简要介绍了波导宽边耦合3dB功分桥的工作原理，重点阐述四耦合窗Ka频段宽带波导宽边耦合3dB功分桥的仿真设计过程、仿真结果以及最终的实物测试结果。最后得到一个性能优良的Ka频段宽带波导宽边耦合3dB功分桥。     

Study of backward propagating Langmuir waves with PIC simulation

The conversion of Langmuir waves into electromagnetic radiations is an important mechanism of solar type III bursts. Langmuir waves can be easily excited by electron beam instability, and they can be converted into backward propagating Langmuir waves by wave–wave interaction. Generally, the backward propagating Langmuir waves are very important for the second harmonic emission of solar type III bursts. In this work, we pay particular attention to the mechanism of the backward propagating Langmuir waves by particle in cell (PIC) simulations. It is confirmed that the ions play a key role in exiting the backward propagating Langmuir waves. Moreover, the electron beam can hardly generated the backward propagating Langmuir waves directly, but may directly amplify the second harmonic Langmuir waves.     

Improved Accuracy Metallic Resonator CVG

Metallic resonator Q-factor is very sensitive to the resonator's material, its thermal and chemical treatment, design, and environment; i.e., pressure and temperature. In order to obtain higher accuracy for CVG it is necessary to use resonator evacuation. Resonator mass plays a very important role in sensitivity to angle rate, in stability of vibration, in response to environmental condition changes, and also to external vibration and shock resistance. tnnalabs Holding Inc. uses a cylindrical resonator with increased rim thickness of up to 2 mmn and more. This concerns resonator material and design parameters selection, material thermal treatment to increase resonator Q-factor, and improved control algorithms in order to increase metallic CVG accuracy. As a result, CVG bias instability of 0.025 degth and random walk of 0.008 degvh for the resonator diameter 43 mmn, and 0.2 deg/h for the resonator diameter 25 mm were obtained. Future opportunities for Innalabs CVG is also discussed herein. Test results are presented for CVG43 and CVG25. Three-axis CVG unit under control of one DSP "Sharc" and IMU parameters are forecasted.     

Relativistic electrons high doses at International Space Station and Foton M2/M3 satellites

The paper presents observation of relativistic electrons. Data are collected by the Radiation Risk Radiometer-Dosimeters (R3D) B2/B3 modifications during the flights of Foton M2/M3 satellites in 2005 and 2007 as well as by the R3DE instrument at the European Technology Exposure Facility (EuTEF) on the Columbus External Payload Adaptor at the International Space Station (ISS) in the period February 20 – April 28, 2008. On the Foton M2/M3 satellites relativistic electrons are observed more frequently than on the ISS because of higher (62.8°) inclination of the orbit. At both Foton satellites the usual duration of the observations are a few minutes long. On the ISS the duration usually is about 1 min or less. The places of observations of high doses due to relativistic electrons are distributed mainly at latitudes above 50° geographic latitude in both hemispheres on Foton M2/M3 satellites. A very high maximum is found in the southern hemisphere at longitudinal range 0°–60°E. At the ISS the maximums are observed between 45° and 52° geographic latitude in both hemispheres mainly at longitudes equatorward from the magnetic poles. The measured absolute maximums of dose rates generated by relativistic electrons are found to be as follows: 304 μGy h⁻¹ behind 1.75 g cm⁻² shielding at Foton M2, 2314 μGy h⁻¹ behind 0.71 g cm⁻² shielding at Foton M3 and 19,195 μGy h⁻¹ (Flux is 8363 cm⁻² s⁻¹) behind les than 0.4 g cm⁻² shielding at ISS.     

Solution of the Problem of Optimal Spacecraft Launching into Orbit Using Reactive Acceleration and Solar Sail in Kustaanheimo–Stiefel Variables

Cosmic Research - Using the Pontryagin maximum principle and the Kustaanheimo–Stiefel variables, the spatial problem of optimal launching into a given orbit of a spacecraft (SC) controlled by...     

数字化检验在航电系统集成生产中的应用

针对航电系统集成生产模式下数字化检验工作的深入研究,系统地总结了航电系统集成检验的内容、方法和工作流程。结合某型飞机航电系统集成数字化检验,构建了航电系统集成生产过程中数字化检验标准的框架结构,为实现航电系统集成生产中数字化检验标准和手段的发展提供了宝贵经验。     

Biomedical problems of EVA support during manned space flight to Mars

Current projects of manned missions to Mars are aimed to their realization in the second-third decades of this century. The purpose of this paper is to determine and review the main biomedical problems, that require a first and foremost decision for safety support of extravehicular activity (EVA) carried out by crewmembers of the Mars expedition. To a number of such problems the authors of the paper attribute a creation of adequate EVA equipment intended, first, for assembly of interplanetary spacecraft on the Earth orbit, performance of maintenance operations and scientific researches on the external surface of spacecraft during interplanetary flight and, secondly, for work on the Mars surface. New generation of space suits with low weight, high mobility and acceptable risk of decompression sickness must be as a central component of EVA equipment. The program for preparation to a Mars expedition also has to include special investigations in order to design the means and methods for a reliable protection of crew against space radiation, to elaborate the approach to medical monitoring and primary medical care during autonomous space mission, to maintain good health condition of crewmembers during EVA under the Mars gravity (0.38 g) after super long-term flight in weightlessness.     

Three-dimensional numerical studies of a jet airflow around the duct platforms of the turbine nozzle clusters

This paper presents the results of three-dimensional numerical studies of hydrodynamics and heat exchange on the models of flat plates in the jet airflow. These results are compared with the experimental data. A three-dimensional model for determining the thermal condition of the nozzle clusters in the conjugated formulation is proposed. Also presented are the data on optimization of the system used for the jet airflow around the duct platforms of the nozzle clusters.