Development of polarization ratio model for sea surface wind field retrieval from TerraSAR-X HH polarization data

In this article, the polarization ratio (PR) of TerraSAR-X (TS-X) vertical–vertical (VV) and horizontal–horizontal (HH) polarization data acquired over the ocean is investigated. Similar to the PR of C-band synthetic aperture radar (SAR), the PR of X-band SAR data also shows significant dependence on incidence angle. The normalized radar cross-section (NRCS) in VV polarization data is generally larger than that in HH polarization for incidence angles above 23°. Based on the analysis, two PR models proposed for C-band SAR were retuned using TS-X dual-polarization data. A new PR model, called X-PR hereafter, is proposed as well to convert the NRCS of TS-X in HH polarization to that in VV polarization. By using the developed geophysical model functions of XMOD1 and XMOD2 and the tuned PR models, the sea surface field is retrieved from the TS-X data in HH polarization. The comparisons with in situ buoy measurements show that the combination of XMOD2 and X-PR models yields a good retrieval with a root mean square error (RMSE) of 2.03 m s^–1 and scatter index (SI) of 22.4%. A further comparison with a high-resolution analysis wind model in the North Sea is also presented, which shows better agreement with RMSE of 1.76 m s^–1 and SI of 20.3%. We also find that the difference between the fitting of the X-PR model and the PR derived from TS-X dual-polarization data is close to a constant. By adding the constant to the X-PR model, the accuracy of HH polarization sea surface wind speed is further improved with the bias reduced by 0.3 m s^–1. A case acquired at the offshore wind farm in the East China Sea further demonstrates that the improvement tends to be more effective for incidence angles above 40°.     

“LOGO”在塑料机械中的应用

把可编程控制器“PLC”中“LOGO”集成块应用于塑料机械中,把可编程序输入到“LOGO”,来表达电器线路对塑料制品的记数和裁刀部分进行自动控制。     

Influences of zinc oxide and an organic additive on the electrochemical behavior of pure aluminum in an alkaline solution

The corrosion behavior of pure aluminum in inhibited and uninhibited 4 MKOH was investigated by means of hydrogen collection, polarization curve measurement and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion of pure aluminum was greatly inhibited by the addition of ZnO and dimethyl amine epoxy propane (designated as DE). EIS and EDAX analyses revealed that ZnO produces its effect by depositing on the aluminum surface, which increases the overpotential of hydrogen evolution. It was also found that the addition of DE could greatly improve the deposition of zinc layers.     

UHMWPE混炼接枝马来酸酐研究

讨论了超高相对分子质量聚乙烯(UHMWPE)混炼接枝马来酸酐(MAH)过程中，单体MAH用量、引发剂DCP用量、交联抑制剂己内酰胺(CAILA)用量、流动改性剂硬脂酸钙(CaSt2)用量及混炼温度、时间等工艺条件对UHMWPE接枝率和凝胶含量的影响。用红外光谱表征了接枝物的存在。并用滴定分析法和重量分析法测定了接枝物UHMWPE～g～MAH的接枝率和凝胶含量。实验表明，MAH用量为5份、DCP为0．15份、CALA为0．1份、CaSt2为1份时。混炼温度175∽180℃。混炼时间14min时，可得到接枝率0．75％、凝胶含量1．48%的UHMWPE接枝物。     

PA-1010/ABS合金的性能研究

研究了以自制的马来酸酐 (MAH)接枝改性ABS(MABS)作为PA 10 10 /ABS增容剂所形成的PA 10 10 /ABS合金的性能。研究结果表明 ,随ABS中马来酸酐接枝量的上升 ,PA 10 10 /ABS合金的冲击强度提高 ,保持PA 10 10与ABS用量在某一恰当配比范围内 ,可得到冲击强度高 ,维卡软化温度较高的合金。     

基于RTX的工程飞行模拟器数据采集与存储系统设计

在一些仿真应用中,由于Windows操作系统较差的实时性,从而给许多半物理仿真试验带来了一些不确定的因素.在充分论证的基础上,引入了Ardence公司的基于Windows的硬实时解决方案RTX（Real-Time eXtension）,并结合某型号飞行器仿真课题总结出了Windows环境下RTX实时应用系统的设计方法与开发流程以及RTX下硬件板卡驱动程序的编写,最后将这种设计方法成功应用在某型号飞行器飞行仿真系统中.实验证明该仿真系统是可靠的、稳定的,整个实验过程中飞行器的飞行数据没有丢失,仿真周期确定,结果正确,RTX仿真程序能够满足系统对实时性和确定性的要求.     

传热设备自动清洗纽带的开孔结构优化研究

对设有开孔结构的自转清洗纽带进行了传热特性及流阻特性研究。结构优化试验的结果表明 :摩擦阻力和传热强化都随开孔面积比率的增大表现出先上升后下降的趋势 ,传热强化的幅度在 2 %— 18%之间 ,摩擦阻力系数在开孔率 18%时最大 ,其中 7#开孔比率纽带的综合性能最佳。因此 ,这种开孔结构的纽带更宜用于中低Re工况下应用 ,在 2 .0m/s以上的高流速工况下应采用高开孔率结构的纽带或螺旋带     

评“异向双螺杆挤出机的发展前景”一文

本文结合Ｊ．Ｌｅｉｎｇａｒｔｎｅｒ先生的文章，从一个新的角度分析了锥形双螺杆和平行双螺杆挤出机各自的特点，对两种双螺杆挤出机作了评价。     

多核DSP的以太网远程程序加载方法

为了解决工业远程控制设备的软件更新带来的成本和效率问题,在研究了以TMS320C6670为核心的DSP系统的结构和程序启动的基础上,提出了基于以太网的DSP程序远程加载方法。该方法主要基于BOOTP协议的广播和以太网UDP协议实现。实践表明,该加载技术灵活可靠,为远程控制系统的调试和更新提供了便利。