面向舰船目标检测的单通道复值SAR图像统计建模方法研究

合成孔径雷达(SAR)成像模式丰富、覆盖范围广、分辨率高，可以长期、动态、宏观地对海洋进行监测。在完全发展的相干斑假设条件下，传统单通道SAR图像舰船目标检测方法主要研究幅度信息。然而，其部分假设条件在高分辨率情形下并非严格成立，因此无法有效利用单通道SAR图像的相位或复值信息。该文面向舰船目标检测应用，将单通道复值SAR图像统计建模方法划分为幅度、相位和复值统计建模3个部分，首先简要综述了单通道SAR图像幅度统计建模方法，然后详细阐述了单通道SAR图像相位和复值统计建模方法，并重点介绍了其建模过程和参数估计方法。在此基础上，该文给出了作者研究小组在基于复值统计信息的单通道SAR图像舰船目标检测方面的部分最新研究结果，并分析展望了下一步研究方向。      

Research on orbital angular momentum communication technology

As the good orthogonality between the different modes of orbital angular momentum (OAM),the application of OAM technology in wireless communication has gained increasing popularity in recent years with great potential for capacity improvement.OAM-based wireless communication technology can effectively improve spectrum utilization,but also brings some challenges.Firstly,the research status and progress of OAM technology in the field of wireless communication were introduced and the relationship between OAM and MIMO technology was compared and analyzed combined with the basic principle of OAM.Moreover,the dispute “Does OAM provides a new dimension?” was concluded.Then,the generation and reception methods of OAM were summarized.The key techniques and application fields were overviewed.Finally,the challenges of the technology in practical application were analyzed and the future development trends and follow-up research directions were point out,which would provide a reference and help for the research in this field.     

整体式挤压油膜阻尼器对管道振动抑制试验

针对管道振动现象，设计了一种整体式挤压油膜阻尼器并分析其刚度影响规律。利用SAP2000软件模拟仿真阻尼减振效果。搭建二维门型管道振动试验台，在管道上安装整体式挤压油膜阻尼器，研究整体式挤压油膜阻尼器控制管道振动的影响规律。结果表明：整体式挤压油膜阻尼器安装在激振源处且与激振力平面平行时的减振效果最佳，较原始振动降幅达51.83%；安装在激振源处且与激振力平面垂直时的减振效果最差；安装两个整体式挤压油膜阻尼器减振效果优于安装一个整体式挤压油膜阻尼器；安装在激振源处的减振效果优于安装在远离激振源的效果。     

基于GA-BP神经网络的电网暂稳极限切除时间预测

本文介绍了一种利用PSASP软件结合GA-BP神经网络的极限切除时间预测方法.通过PSASP软件搭建三机九节点系统,模拟系统发生三相短路故障,得到实验数据,将实验数据分为训练集和测试集,构建基于GA-BP的极限切除时间预测模型.结果表明,基于GA-BP模型的极限切除时间预测值与实际值基本一致,且GA-BP模型的预测精度高于BP模型.     

Targeted editing of intronic-splicing silencer enhancement of SMN2 Exon 7 inclusion by CRISPR/Case 9

Spinal muscular atrophy (SMA) is an autosomal recessive hereditary neuromuscular disease. Exon 7 and 8 of survival of motor neuron 1 (SMN1) gene or only exon 7 homology deletion leads to the failure to produce a full-length SMN gene. The copy number of SMN2 gene with high homology of SMN1 affects the degree of disease and was the target gene for targeting therapy, in which splicing silencer in intron 7 was the key to suppress the inclusion of exon 7. In this study, we projected to use CRISPR/Case 9 for the targeted editing of intronic-splicing silencer (ISS) sequence to promote the inclusion of SMN2 exon 7 and increase the production of SMN2 full-length (FL) gene expression. It happens that there was a protospacer adjacent motif (PAM) at one end of the ISS sequence according to the design of sgRNA. The recombinant vector of sgRNA HSMN2 CRISPR/Case 9 was constructed and transfected into HEK293 cells. Sequencing results showed that the ISS sequence could be edited accurately and targeting in the predicted direction, in which deleting small fragments, inserting small amounts and mutation. Quantitative analysis of RT-PCR products by restriction enzyme of DdeI digestion showed that the FL of SMN2 increased by 8% (P < 0.05). In the primary cultured chondrocytes of SMA mice, in which sgRNA HSMN2 CRISPR/Case9 recombinant vector transfection could increase the SMN2 FL gene by 23% (P < 0.05) and significantly improve SMN protein levels (P < 0.05). CRISPR/Case 9 is an effective tool for gene editing and therapy of hereditary diseases, but it is rarely reported in the treatment of SMA diseases. This study shows that CRISPR/Case 9 was first used for the precision target of ISS sequence editing, which can effectively promote the production of SMN2 FL gene expressions, in which there was an important clinical reference value.     

指数反余弦函数变换灰色预测模型

将指数反余弦函数变换aarccosx(a≥e)应用到粮食产量数据的实证分析中,可变参数a取值可以提高GM(1,1)模型的预测精度.     

基于用户体验的压路机操纵手柄交互品质研究

目的以压路机操纵手柄为对象,探讨交互品质研究方法,改进用户体验。方法对交互品质进行解析,由用户体验与交互品质的关联性,提出基于用户体验的交互品质研究方法;面向压路机操纵手柄典型任务进行用户体验研究,梳理压路机手柄的操作流程,并对交互行为进行聚类分析,结合语义分析构建用户体验词库,运用半结构式访谈与问卷调查,以定量与定性方法相结合对驾驶员的操纵体验进行调研;以专家研讨的形式进行驾驶员的操纵体验向交互特征的映射,构建交互特征集,进而对操纵手柄的交互品质进行分析与阐释。结果得出了压路机操纵手柄的交互特征与交互品质。结论通过用户体验可以映射交互特征,得到了交互品质,对于从交互品质的角度指导交互设计提供了借鉴。     

乌溪江流域下游特殊干旱期的应急供水方案

针对乌溪江流域下游水资源供需状况,将乌溪江流域特殊干旱期的典型年份作为研究对象,分析应急供水控制条件,得到不同应急级别相应湖南镇水库控制水位.同时,根据不同级别的干旱预警,研究确定了应急供水方案启动程序与应急供水方案.     

等离子体预处理对解淀粉芽胞杆菌生长和α-淀粉酶分泌的影响

本研究采用低真空室温射频等离子体对解淀粉芽胞杆菌CICC 10035进行预处理，通过改变放电功率、处理时间和工作气压等参数，筛选最佳工艺条件，并使用蛋白质组学技术，对差异蛋白质进行生物信息学分析，探讨等离子体预处理对菌体生长和产酶性能的影响。结果表明，等离子体预处理的最佳工艺条件为：放电功率120 W，处理时间15 s，工作气压135 Pa。在最佳条件下，发酵48 h后，α-淀粉酶酶活超过400 U/mL，与对照样相比提高约20%。蛋白组学分析表明，等离子体预处理对菌体的蛋白合成及代谢产生了较强的正效应，尤其在DNA修复和氨基酸合成上，一方面提高了菌体活性，延缓其衰亡过程；另一方面促进了α-淀粉酶在菌体内的合成和分泌。