软件接收机中调频信号的一种解调算法

本文提出了软件接收机中调频信号解调的一种算法,文章最后给出了一个具体实例的仿真结果.     

圆草捆缠膜机的设计与研究

本文论述了圆草捆缠绕式青贮的原理，以及发展圆草捆缠膜机的必要性。并结合我国国情，对圆草捆缠膜机进行合理配置及优化设计。     

高燃速HTPB/IPDI推进剂低温力学性能研究(Ⅰ)细AP及工艺助剂PA的影响

研究了细粒度AP及工艺助剂PA含量对丁羟高燃速推进剂低温(-40℃)力学性能的影响,结果显示:大量细粒度AP加入高燃速配方中,一方面加剧了单向拉伸过程中填料(主要是细AP)颗粒附近的应力集中;另一方面降低了填料/粘合剂间的粘结强度,是造成低温力学性能偏低的主要原因.由于工艺助剂PA极性及刚性,使得它易于富集于填料表面,低温下降低了界面层的柔性,物理作用也极大地束缚了填料附近粘合剂网络的分子运动,因此,它在改善工艺性能的同时,对推进剂低温力学性能有不利影响.     

可压缩流体恒温热线风速仪校准方法

开展了恒温(CT)热线风速仪校准方法的研究,以满足可压缩流体中湍流度测量需求。将对数函数与多元回归技术相结合,建立了恒温热线风速仪校准的数学模型,并进行了风洞湍流度测量试验验证。在马赫数Ma=0.3~0.55范围内进行了校准试验,根据建立的数学模型对试验数据进行拟合,拟合优度R2=0.999 82,平均绝对速度偏差Δu=0.18m/s,基本满足了恒温热线风速仪校准精度要求。对马赫数Ma=0.55条件下流场进行了湍流度测量,速度测量偏差为0.034%,流场湍流度Tu=0.14%。试验结果证明了恒温热线风速仪应用于可压缩流体速度测量的可行性。     

Preparation of bimodal grain size 7075 aviation aluminum alloys and their corrosion properties

The bimodal grain size metals show improved strength and ductility compared to traditional metals; however, their corrosion properties are unknown. In order to evaluate the corrosion properties of these metals, the bimodal grain size 7075 aviation aluminum alloys containing different ratios of coarse(100 μm in diameter) and fine(10 μm in diameter) grains were prepared by spark plasma sintering(SPS). The effects of grain size as well as the mixture degree of coarse and fine grains on general corrosion were estimated by immersion tests, electrochemical measurements and complementary techniques such as scanning electron microscope(SEM) and transmission electron microscope-energy disperse spectroscopy(TEM-EDS). The results show that, compared to fine grains, the coarse grains have a faster dissolution rate in acidic NaCl solution due to the bigger size,higher alloying elements content and larger area fraction of second phases in them. In coarse grains,the hydrogen ions have a faster reduction rate on cathodic second phases, therefore promoting the corrosion propagation. The mixture of coarse and fine grains also increases the electrochemical heterogeneity of alloys in micro-scale, and thus the increased mixture degree of these grains in metal matrix accelerates the corrosion rate of alloys in acidic NaCl solution.     

基于工作过程的《制冷技术》课程教学设计

根据高等职业教育新的课程理念,对《制冷技术》课程的教学进行了改革。基于对实际工作过程的分析和思考,设计了学习情境,重构了课程内容,以学生为主体组织实施教学,创新了考核方法,有效地提高了教学效果。     

农民培训工作档案的建立与功能——以杨凌职业技术学院为例

随着我国＂城镇化＂进程的进一步推进和党中央对三农问题的高度关注,省级部门对农民培训的力度愈来愈大,并呈现出良好的势头,成为新农村和城镇化建设的重要抓手。因此,将农民培训工作中的原始文件资料进行整理、加工、归档,进而开发和使用,对于进一步搞好新时期农民培训工作,推进农村成镇化建设具有十分重要的意义。     

Near real-time assimilation in IRI of auroral peak E-region density and equatorward boundary

The paper describes the method and initial results of assimilating the auroral peak E-region density (NmE) and the auroral equatorward boundary (EB) into the International Reference Ionosphere (IRI). The NmE and EB are obtained using a FUV based auroral model or FUV measurements in near real-time. Initial results show that the auroral NmE is often significantly larger than the NmE due to the solar EUV. This indicates the importance of including the contribution of precipitating electrons in IRI. The global equatorial boundary helps to improve the specification of the sub-auroral ionosphere trough in IRI. An IDL software package has been developed to interactively display the IRI parameters with assimilated NmE and EB. It can serve as an operational tool for space weather monitoring.     

FastCAM软件在等离子切割机中的应用

FastCAM软件主要针对等离子、火焰、激光和水刀等数控切割机,用于任意形状零件的绘图、编程、套料、校验和数控切割.通过FastCAM.充分结合人的套料经验和计算机的运算速度可以提高钢材套料率.有效节省钢材;提高编程、套料和切割工作效率,有效提高切割生产效率.     

化解乡村债务的基本思路及实现途径

乡村债务包括存量债务和增量债务两个部分，解决乡村债务问题就要从这两个方面入手。对于存量债务，可以通过债务重组的方式进行化解；对于增量债务文章提出了在新农村建设中，不仅不应一味地避免乡村新增债务，而且应该积极地采取有效措施，使乡村新增债务尤其是良性债务维持在适度的规模和水平之上的观点。