基于IEEE1588的分布式柔性测压带系统设计

为了研发一套分布式翼面柔性测压带系统,实现以表面贴附的方式测量飞机翼面压力,同时满足大规模分散式的传感器节点数据的同步采集、实时传输和本地存储等功能,提出系统总体设计方案,提供了硬件设计方法和软件设计流程。测试了系统的各项性能,并进行系统性能评估。测试结果表明:该系统达到了预期的技术指标,符合测试平台的要求;该系统是通用的,可以将压力传感器换成其他类型的传感器,尤其对于需要大量传感器的测试环境,其提供了一种安装方便、扩展灵活、数据传输可靠的解决方案。

运输机襟翼压力分布飞行试验测量

为了飞行试验测量运输机襟翼压力分布,国内首次研制了测压带。提供了直接打孔法与测压带法的飞行试验比对测量结果,表明测压带法是准确适用的。在飞行试验中采用测压带测得了某后退双开缝襟翼起飞、着陆构型的压力分布,结果表明襟翼起飞构型的气动设计有待改进,襟翼着陆构型气动效率较高。测压带法适用于飞行试验空气动力学研究和飞机气动特性的演示验证。

亚音速飞机压力分布测量

简要地介绍了亚音速飞机压力分布测量的飞行试验技术，并给出了部分试验结果。对用测压带法进行机翼压力分布测量及滑流对压力分布的影响等问题进行了讨论。

压力分布飞行实测进展研究

飞行载荷试飞验证对飞机的结构强度设计和气动性能设计具有重要的意义,新型飞机都要进行飞行载荷测量的飞行试验。压力分布法是飞行载荷测量的一种有效手段,能获取测试剖面处的压力分布,能获得其他专业所需的气动特性,试验成本低。文章对国内外飞行试验中压力分布测量技术研究现状及相关方法进行了介绍。最后,对压力分布测量在飞行试验中的应用提出展望。

Relationship between Rice Planthopper Occurrence Area in China and Atmospheric Circulation Indices

[Objective] This study aimed to establish models based on atmospheric cir- culation indices for forecasting the area attacked by rice planthopper every year, and to provide guide for preventing and controlling planthopper damage. [Method] The data related to rice planthopper occurrence and atmospheric circulation were collected and analyzed with the method of stepwise regression to establish the prediction models. [Result] The factors significantly related to the area attacked by rice plan-thopper were selected. Two types of prediction models were established. One was for Sogatella furcifera （Horvath）, based on Atlantic-Europe circulation pattern W in October in that year, Pacific polar vortex area index in October in that year, North America subtropical high index in August in that year, Atlantic-Europe circulation pattern W in June in that year, northern boundary of North America subtropical high in February in that year, Atlantic-Europe polar vortex intensity index in October in that year and Asia polar vortex intensity index in November in the last year; the other type of prediction models were for Nilaparvata lugens （Stal）, based on the Eastern Pacific subtropical high intensity index in July in that year, northern hemi- sphere polar vortex area index in October in the last year, Asia polar vortex strength index in November in the last year, north boundary of North America-At- lantic subtropical high in September in that year, north boundary of North Africa-At- lantic-North America subtropical high in January in that year, sunspot in September of the last year and eastern Pacific subtropical high area index in September in that year. [Conclusion] With the stepwise regression, the forecasting equations of the rice planthopper occurrence established based on the atmospheric circulation indices could be used for actual forecast.

Comparison of remote sensing data with in-situ wind observation during the development of the South China Sea monsoon

Wind measurements derived from QuikSCAT data were compared with those measured by anemometer on Yongxing Island in the South China Sea (SCS) for the period from April 2008 to November 2009. The comparison confirms that QuikSCAT estimates of wind speed and direction are generally accurate, except for the extremes of high wind speeds (>13.8m/s) and very low wind speeds (<1.5m/s) where direction is poorly predicted. In-situ observations show that the summer monsoon in the northern SCS starts between May 6 and June 1. From March 13, 2010 to August 31, 2010, comparisons of sea surface temperature (SST) and rainfall from AMSR-E with data from a buoy located at Xisha Islands, as well as wind measurements derived from ASCAT and observations from an automatic weather station show that QuikSCAT, ASCAT and AMSR-E data are good enough for research. It is feasible to optimize the usage of remote-sensing data if validated with in-situ measurements. Remarkable changes were observed in wind, barometric pressure, humidity, outgoing longwave radiation (OLR), air temperature, rainfall and SST during the monsoon onset. The eastward shift of western Pacific subtropical high and the southward movement of continental cold front preceded the monsoon onset in SCS. The starting dates of SCS summer monsoon indicated that the southwest monsoon starts in the Indochinese Peninsula and forms an eastward zonal belt, and then the belt bifurcates in the SCS, with one part moving northeastward into the tropical western North Pacific, and another southward into western Kalimantan. This largely determined the pattern of the SCS summer monsoon. Wavelet analysis of zonal wind and OLR at Xisha showed that intra-seasonal variability played an important role in the summer. This work improves the accuracy of the amplitude of intra-seasonal and synoptic variation obtained from remote-sensed data.

Predicting Western Pacific Subtropical High Using a Combined Tropical Indian Ocean Sea Surface Temperature Forecast

Weather and climate in East China are closely related to the variability of the western Pacific subtropical high(WPSH), which is an important part of the Asian monsoon system. The WPSH prediction in spring and summer is a critical component of rainfall forecasting during the summer flood season in China. Although many attempts have been made to predict WPSH variability, its predictability remains limited in practice due to the complexity of the WPSH evolution. Many studies have indicated that the sea surface temperature(SST) over the tropical Indian Ocean has a significant effect on WPSH variability. In this paper, a statistical model is developed to forecast the monthly variation in the WPSH during the spring and summer seasons on the basis of its relationship with SST over the tropical Indian Ocean. The forecasted SST over the tropical Indian Ocean is the predictor in this model, which differs significantly from other WPSH prediction methods. A 26-year independent hindcast experiment from 1983 to 2008 is conducted and validated in which the WPSH prediction driven by the combined forecasted SST is compared with that driven by the persisted SST. Results indicate that the skill score of the WPSH prediction driven by the combined forecasted SST is substantial.

High temperature property studies of the 6H-SiC MOS capacitor

N-type and p-type 6H-SiC metal oxide semiconductor (MOS) capacitor samples are fabricated with a typical method,and the high frequency capacitor voltage (C-V) curves of these samples are measured at temperatures ranging from 293 to 533 K.There exists huge difference between the n-type and p-type samples.Flat-band voltage shift of the n-type sample becomes larger with temperature rising,but that of the p-type sample have very little change.This may be caused by the residual Al in the p-type oxide.Both types of the SiC samples follow the same rule of flat-band voltage changing with temperature.But their mechanisms are different as temperature is above 453 K.Of both types the p-type SiC is more suitable for high temperature applications.

Underwater sonar target imaging via compressed sensing with M sequences

Due to the low sound propagation speed, the tradeoff between high azimuth resolution and wide imaging swath has severely limited the application of sonar underwater target imaging. However, based on compressed sensing(CS) technique, it is feasible to image targets with merely one pulse and thus avoid the above tradeoff. To investigate the possible waveforms for CS-based underwater imaging, the deterministic M sequences widely used in sonar applications are introduced in this paper. By analyzing the compressive matrix constructed from M sequences, the coherence parameter and the restricted isometry property(RIP) of the matrix are derived. Also, the feasibility and advances of M sequence are demonstrated by being compared with the existing Alltop sequence in underwater CS imaging framework. Finally, the results of numerical simulations and a real experiment are provided to reveal the effectiveness of the proposed signal.