PXI在测控系统中的应用

随着有关PXI总线的规范和产品的推出，由于优良的性能指标和适宜的价格，使其受到各相关行业的广泛关注。对风洞测控系统的结构和系统配置作了具体的阐述，并对PXI总线在具体使用中的效果和特点作了较详细的介绍。     

风能地板辐射采暖系统

随着经济快速发展,化石燃料已被大量开发和使用,一方面人类面临能源日渐匮乏的危机,另一方面能源大量浪费也引起全球环境问题.本文以环保和节能为目标,提出一种综合利用风力发电技术、热泵技术和低温地板辐射采暖技术的新型采暖模式,对使用可再生风能进行采暖,进行了可行性探讨.     

农机报表管理系统的设计与实现

以新疆生产建设兵团农机报表管理系统为例，介绍了基于C／S和B／S模式的农机报表管理系统的设计与实现，并对其系统开发中的关键技术等内容进行了探讨。     

钢板仓受风载作用的有限元分析

对高 14.76m ,直径 12m的螺旋卷边钢板筒仓在空仓风载工况下进行了有限元分析。计算结果表明 ,在风载作用下 ,仓体的强度不是主要问题 ,而仓顶开口处刚度较弱。     

Estimating Sampling Errors in REA Survey: A Model Approach for the Synthetic Presentation of Results for Main Variables Involved in Economic Analysis

A new sample business survey for agriculture, the REA survey, and a project of integration with the FADN network (RICA in Italy) have significantly changed the production of statistical information nowadays available with reference to the agricultural sector. On the basis of this relevant information, new economic analyses are being developed on farms’ performance, agricultural households’ income and the Common Agricultural Policy (CAP). In this paper the authors estimate the relationship between the levels of variables of interest and their sampling errors using models in order to improve the accessibility of the information on estimates accuracy to the final users (agricultural analysts, policy makers). The paper is the result of a joint research of the three authors. Sections 1–3 and 6 by Pizzoli, Sects. 4 and 5 by Rondinelli, Sect. 7 by Filiberti, conclusions joint to the three authors.     

Evolution of the Alfvénic correlation in the solar wind

Summary The radial evolution of Alfvénic correlation is such that its value decreases with increasing heliocentric distance. So far this behaviour has been interpreted as an increase in the local production of ?inward? modes interacting destructively with the ?outward? modes. This work, which deals with largescale turbulence, shows that local generation phenomena are not commonly found in the solar wind and that the Alfvénic character of the fluctuations mainly depend on the ?outward? modes alone. The interaction of these modes with density and/or magnetic-field structures convected by the wind causes their destruction and a consequent depletion of the Alfvénic correlation. The same effect would be obtained if ?inward? modes were really present. Our conclusions are that large-scale ?inward? modes are the spectral counterpart of non-propagating field and plasma structures convected by the solar wind and identified as both compression regions and pressure balance structures. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.     

Nonlinear oblique propagation of magnetohydrodynamic waves in the solar wind

Summary Oblique propagating magnetohydrodynamic waves with various wave forms and amplitudes are observed both at the Earth's foreshock and at comets. The possibility of interpreting some observational results in terms of nonlinear evolution of one- and two-dimensional hydromagnetic waves is investigated. For this purpose both analytical and numerical techniques are employed. It is found that an initial monochromatic wave changes its polarization giving origin to magnetosonic shocks and rotational discontinuities; the time evolution of density-magnetic-field correlation is studied, as a function of the plasma parameters and of the propagation angle. In the two-dimensional case both a transverse instability and a self-focusing effect may take place. Moreover, a two-dimensional magnetosonic solution is found, in which the density fluctuations are driven by the total pressure fluctuation as in a one-dimensional simple wave. These theoretical predictions compare well with the features observed in the solar-wind waves. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.     

风洞风表检定仪8031系统研制

本文是在笔者最近研制的ＦＢＹ－１型风洞风表检定仪８０３１系统的基础上整理而成的，主要介绍了这个简单而实用系统的基本组成、软件设计以及针对现场实际问题所采用的有效措施     

地面突风对通航飞行器的影响及数值模拟研究

突风一直以来都是危及飞行安全的重要气象要素之一,造成国民经济和人民生命财产的损失。利用常规观测资料、ADWR-X多普勒气象雷达资料和ERA5逐小时再分析资料,对四川盆地西部一次爆发性大风过程中风场的精细化特征、成因及对飞行的影响进行诊断和模拟研究,结果表明：此次大风过程风速增长快,爆发性强。地面风速自午后开始出现4次波动,且每一次波动期间风速峰值呈增加趋势,时间呈缩短趋势。由于第4次波动风速呈爆发性增加,最大瞬时风达到了16.1 m/s,地面风速脉动值超过5 m/s,致使跑道区域内流场的不稳定性增加,起降跑道侧风值超过了中小型飞行器的起降标准。高空动量下传对本次大风过程中风速的爆发性增加起主导作用。中层强偏南气流与低层偏北急流配和,中层辐合以及低层辐散下沉的垂直结构使得低层下沉气流异常强劲,将900～850 hPa的大风核快速向地面传导。通过天气研究与预报(weather research and forecasting, WRF)模式四重嵌套对本次过程进行模拟,表明WRF对盆地西部冷空气补充南下引起的在风速演变趋势、风速最大值和大风影响时段的风向有较好的模拟能力,对飞行起飞和着陆有一...     

高层建筑外附雨篷的表面风压和气动力系数

采用风洞试验方法研究高层建筑外附雨篷的风压特征,分析风压系数、风压相关性、非高斯性和整体升力系数随风向角的变化,给出围护结构的设计风压,最后研究倾角和出挑长度对整体力系数的影响. 研究发现,高层建筑外附雨篷上表面风压系数在正迎风时最大值接近1.4,系气流受到后方高层建筑的阻挡下翻导致;上、下表面的最大整体压力系数出现正迎风情况,最大值分别为1.24和0.76;上、下表面的最大整体升力系数出现侧风面,最大值分别为1.13和1.01;上下叠加后测点风压的非高斯性比单表面增强;上表面和下表面的升力系数在0°~70°风向呈现高斯分布,在80°~180°风向呈现较强的非高斯分布;高层建筑外附雨篷上表面的极值正压大于下表面;雨篷整体升力系数按照倾角-10°、0°、10°依次递增.