固冲火箭技术的发展与展望

通过若干典型例子系统总结了目前固冲火箭技术的研究与进展情况,着重指出了该技术在达到实际应用之前尚存在的关键技术问题,并对今后的研究与发展方向提出了建议。     

法国SPOT地球观测卫星

该文介绍法国SPOT卫星系列。     

光纤氢传感技术的研究现状及其应用前景

分析了光纤氢传感技术发展的现状和特点，比较了几种典型光纤氢传感器的结构和工作原理。指出了光纤氢传感技术是测量易爆环境下氢气浓度的有效方法，并对光纤氢传感技术的应用前景和有待解决的问题进行了讨论。     

国外地球同步轨道遥感卫星发展初步研究

地球同步轨道遥感卫星因具备高时效性及持续探测能力等优势,已成为当前国际遥感卫星领域一个重要的发展方向。文章围绕地球同步轨道遥感卫星,重点针对光学、微波、电子侦察等国际地球同步轨道遥感卫星及卫星平台发展动态、发展趋势开展了调研与分析,梳理出国际发展情况对中国地球同步轨道遥感卫星领域发展的启示。文章从地球同步轨道遥感卫星领域发展战略的高度,进一步提出支撑该领域发展需重点突破的关键技术。     

Numerical analysis of deflection control of a gas plasma jet based on magnetohydrodynamic staggered electrode configuration

To control the deflection of the gas plasma jet, a new analytical method is proposed based on the Magnetohydrodynamic(MHD) technique. Based on the typical MHD power generation model, the applied voltage is applied to the staggered electrodes, that is, a pair of electrodes on the same side wall are connected to generate an axial current in the channel. Under the action of the magnetic field perpendicular to the direction of the flow, the plasma is subjected to electromagnetic forces perpendicular...     

Measurements of heat transfer and pressure in a trailing edge cavity of a turbine blade

 An experimental investigation is conducted to obtain the heat transfer and pressure drop data for an integral trailing edge cavity test section that simulates a novel turbine blade's internal cooling passage with bleed holes. Local heat transfer is measured on both the suction and pressure sides by a transient liquid crystal technique, while pressures at six positions are recorded by pressure calibrators. Moreover, flow characteristic and its effect on heat transfer are analyzed for conditions with or without bleed flow. The experimental results show that, in the cases with bleed flow, local heat transfer on the pressure side exceeds that on the suction side in the first and second channels. In the cases without bleed flow, in the first and third channels, local heat transfer on the suction side weakens whilst it increases significantly on the pressure side. For the second channel, non-bleed condition leads to a more balanced heat transfer distribution between the upstream and downstream channel. Besides, after the bleed holes are blocked, heat transfer in the first bend region on the suction side declines sharply, while the opposite phenomenon occurs for the second bend region on the pressure side. In both bleed and non-bleed cases, the total pressure of six measurement positions decreases continuously along the channel at the same Reynolds number and it promotes for higher Reynolds number. Among all the measurement points, under the same flow rate condition, the highest speed occurs at Position 5, which also shows the maximum difference between the total and static pressures. When the bleed holes are blocked, the total pressure at each measurement position appears to increase.     

Investigations into sensing characteristics of circular thin-plate electrostatic sensors for gas path monitoring

Circular thin-plate electrostatic sensors are promising in gas path monitoring due to their advantages of non-intrusiveness and easy installation. The spatial sensitivity and filtering effect are two important performance parameters. In this paper, an analytically mathematical model of induced charge on a circular thin-plate electrode is first derived. Then the spatial sensitivity and filtering effect of the circular electrostatic sensor are investigated by numerical calculations. Finally,experimental studies are performed to testify the theoretical results. Both theoretical and experimental results demonstrate that circular thin-plate electrostatic sensors act as a low-pass filter in the spatial frequency domain, and both the spatial filtering effect and the temporal frequency response characteristics depend strongly on the spatial position and velocity of the charged particle. These conclusions can provide guidelines for the optimal design of circular thin-plate electrostatic sensors.     

Assessing the feasibility of involving gaseous products resulting from physicochemical oxidation of human liquid and solid wastes in the cycling of a bio-technical life support system

The study addresses the possible ways of involving gaseous products produced by “wet” incineration of human wastes mixed with H₂O₂ in an alternating electric field in the cycling of the physical model of a bio-technical life support system (BTLSS). The resulting gas mixture contains CO₂ and O₂, which are easily involved in the cycling in the closed ecosystem, and NH₃, which is unacceptable in the atmosphere of the BTLSS. NH₃ fixation has been proposed, which is followed by nitrification and involvement of the resulting products in the mass exchange of the closed system. Experiments have been performed to show that plants can be grown in the atmosphere resulting from the closing of the gas loop that includes a physicochemical installation and a growth chamber with plants representing the phototrophic compartment of the BTLSS. The results of the study suggest the conclusion that the proposed method of organic waste oxidation can be a useful tool in creating a physical model of a closed-loop integrated BTLSS.     

一种测定大值的风速计

简单叙述了研制1种大风速值简易精密测量仪器原理和方法，并对测量误差进行了估算。     

2021 Turkey mega forest Fires: Biodiversity measurements of the IUCN Red List wildlife mammals in Sentinel-2 based burned areas

Mega wildfires are one of the environmental disasters worldwide. This study evaluates the pre-fire species diversity and the indirect effects, including habitat loss for one of the largest wildfires in Manavgat (Antalya-Turkey) in 2021, with a two-step methodology. Here, (1) burnt areas in the Manavgat district (2021) were detected with remote sensing data from Sentinel-2A by delta Normalized Burn Ratio calculation for a selected area in Google Earth Engine, and (2) mammals' habitat vector data of International Union for Conservation of Nature (IUCN) Red List were integrated into Habitat and Biodiversity modelling of Terrset to analyze the alpha, beta, gamma diversity and Range Restriction Index for the wildfire region. In the total 4210 km² study area, 696 km² of the area was damaged by different fire severity; also, there were 56 mammal species' habitats here. These species include bats (i.e. Nyctalus leisleri), felids (i.e. Felis chaus), rodents (i.e. Rattus norvegicus) and large mammals (i.e. Ursus arctos). 88 % of these species are in IUCN's Least Concern category. The remaining classes are Near Threatened (3.7 %) and Vulnerable (7.4 %). This study also indicated that the burnt area's species richness does not totally consist of endemic species. Therefore, pre-fire species richness analyses of this study can be a base for further studies about the species' post-fire activity and occupancy.Furthermore, the 2021 mega wildfires show us the necessity of wildfire monitoring and risk studies in the entire Mediterranean ecosystem to evaluate the risks to the Sustainable Development Goals. Therefore, post-fire spatial data, fire migration monitorization, and recording of the species' activities should be performed temporally. In this way, the ability of wildlife's recovering, and the direct and indirect effects of the fire will be examined for ecosystems in the long term.