美国改进型一次性运载火箭发展概况

介绍美国新一代运载火箭系列的研制计划。该计划的目的是替代重型“大力神”、中型“德尔它”和“宇宙神”运载火箭系列，使成本降低到现有运载火箭的２５％～５０％。改进型一次性使用运载火箭的第一次发射预定在２００１年。     

标准化与企业发展刍议

企业只有利用标准化原理,将特有专长延伸为专业优势,方能在市场经济的竞争中谋敢发展.     

西部大开发中的人力资源开发浅谈

本文通过对西部地区现有人才状况的简单分析 ,提出了西部地区要更新人才观念 ,制定切实可行的政策 ,留住和吸引人才。要改变现有的人才浪费现象 ,通过开展多种形式的培训 ,特别是思维训练和观念变革的培训 ,使现有人才迅速适应WTO的有关规则 ,跟上时代的变化步伐。同时 ,尽可能创造宽松的环境条件 ,吸引国内外优秀人才回归。利用西部大开发提供的历史机遇 ,发挥各类人才的聪明才智 ,为西部地区经济腾飞做出贡献     

垂直发射战术导弹中捷联系统的工程设计问题

本文对捷联系统在垂直发射战术导弹中的工程应用问题作了较深入的探讨。这些问题包括如何使用弹体姿态信息,如何判别计算误差,采用怎样的初始对准方法以及如何描述动态特性等。     

制造业的发展趋势

本文阐述了作者对于21世纪制造业发展趋势的观点，总结出未来制造业的几个特点，简要介绍了敏捷制造、全球制造和绿色制造等几种先进制造模式。     

充气气囊减速方案的气动设计研究

减速是航天飞行器必须面对的问题。充气气囊减速方案利用柔性编织材料外加涂层方式构成气囊，利用气体发生器快速产生高压气体，集防热、减速和着陆减振功能于一体，重量轻、成本低、适用范围广、可靠性高。设计了满足减速需求的气囊外形，利用数值求解NS方程和工程计算方法进行了气动力的预测和比较分析，利用六自由度动力学模型与气动力的耦合计算，对减速效果进行了计算与分析，并对热环境、温度场、应力、热应力及变形进行了计算，还对分离不确定性进行了研究。地面引导性风洞试验和理论分析表明，充气气囊减速方案具有十分明确的减速效果和优点，可用于未来航天飞行器实现减速飞行目的的技术方案。     

Influence of the gravitational vertical on geometric visual illusions

The occurrence of geometric orientation illusions and the perception of ambiguous figures were analyzed in 24 subjects during static body tilt relative to gravity on Earth. Results showed that illusions such as the Rock's diamond/square, the Ponzo illusion, and orientation contrast illusions occurred less frequently, and that depth reversal of ambiguous figures took more time when subjects were lying on their side or supine compared to upright, thus suggesting that the gravitational reference plays a significant role in these “visual” illusions. The structure of images, our representation of the environment, and orientation relative to gravity are all integral parts in interpreting visual images. In a weightless environment where no gravitational reference can be used, it is expected that similar alterations in visual perception will occur.     

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.     

Numerical study of traveling ionosphere disturbances with vertical incidence data

High frequency ionosphere vertical sounding, as an important and representative application for detecting the ionosphere and studying the characteristics of radio propagation, can be utilized to monitor the ionosphere continuously variation and to acquire the ionosphere asymmetrical features of diverse scale above the ionosphere vertical sounding stations. This is a first article on real time application of numerical methods to obtain the parameters of traveling ionosphere disturbances (TIDs) using vertical incident ionograms. In this paper, the distribution of ionosphere electron density with TIDs is constructed using a background ionosphere model superimposed a perturbation theory model. The background ionosphere electron density is modelled by the inversion of vertical incident ionograms which are observed before the appearance of the disturbance. Based on the fourth order Adams-Bashforth-Moulton (the so-called ABM) predictor corrector method, instead of Runge-Kutta method, the fast digital ray tracing method is established. According to process of the disturbed trace simulation and parameters inversion, the characteristic parameters of ionosphere disturbance at different detection time can be obtained in real time. The numerical analysis of TIDs is then captured completely.     

Plasma transport process in the equatorial/low-latitude ionosphere

The behaviour of the equatorial/low-latitude ionosphere and the transport processes during magnetic disturbed and quiet periods of a high solar activity year, 2014, in the American sector are investigated. Parameters used include vertical drift (Vz), transport term (W), NmF2, hmF2 and scale-height (H). The F2 plasma variations followed the diurnal local solar pattern, being higher at daytime. The sunset maximum and sunrise minimum peaks of hmF2 were directly opposite to the scale height (H) pattern. The plasma distribution was basically controlled by combined actions of the electrodynamic convection/thermospheric composition, which is geomagnetic activity dependent. The annual, semi-annual and winter-anomalies of the F2 parameters were higher at the dip equator in comparison with the low-latitude. The Vz pre-reversal peak magnitude coincided with hmF2 peak and the effects are more pronounced during geomagnetic disturbed conditions. The transport term pattern was similar to that of the scale height and it is suggested as a proxy parameter for quantifying low-latitude plasma irregularities and distribution of thermospheric composition.