C-半群的紧性

引入了算子为 C-紧的定义及紧的 C-半群的概念 .讨论了紧的 C-半群的一些性质 ,并给出了 C-半群为紧的一个充要条件 .     

无源光纤脉冲电压电场传感器的研究

研究了一种利用电光晶体的一次电光效应测量脉冲电压和电场的方法,给出了光纤电压电场传感器的基本结构和测量原理,计算和对比了BGO和LN等几种不同晶体对测量灵敏度的影响.利用HP-8011A型脉冲信号发生器做为信号源,进行了初步的设计和测试,实验结果表明LN晶体具有较高的灵敏度、线性度以及较好的频率响应.     

基于近邻成分分析的短期风电功率集成预测

针对短期风电功率预测关键气象因素影响程度的差异和单一模型预测精度不足的问题,提出一种基于近邻成分分析(neighborhood components analysis, NCA)特征加权和Stacking集成预测的短期风电功率预测模型。考虑气象特征对风电功率影响程度不同,利用NCA对气象特征进行加权,将加权特征作为模型输入,强化关键特征的影响程度;在此基础上,构建多个基预测器预测风电功率,并利用结合器将预测结果融合,建立Stacking集成预测模型。算例分析表明,以加权特征作为输入的Stacking集成预测模型具有更高的短期风电功率预测精度。     

飞行员异常事件处理能力的脑电评估方法

为客观准确评估飞行员在飞行过程中对发生的异常事件的处理能力,在A320NEO/CEO全任务飞行模拟器中设定异常事件,并利用脑电设备进行实验信号采集。脑电信号（Electroencephalography,EEG）经独立成分分析（Independent Component Analysis,ICA ）等预处理后,通过近似熵法与小波包分析法提取相应特征以构建特征集,再选择适用于脑电领域的机器学习算法构建模型,并引入F1值、ROC-AUC曲线等模型评价指标对构建的模型进行评价。分析结果显示随机森林算法所构建的模型的分类效果最好,其准确度为88.5%,F1值为84.2%,AUC值为0.95。研究表明该模型预测精度良好,可用于辅助飞行员训练与评估。     

农田荒漠过渡带包气带土壤水盐运移规律研究

为实现农田区和荒漠保护区植被协同发展,通过石羊河流域下游某试验场原位试验研究农田荒漠过渡带包气带土壤水盐运移规律。结果表明：农田荒漠过渡带上,荒漠区土壤包气带水盐运移与农田区灌溉息息相关。灌溉后,农田区土壤盐分随灌溉水进入地下水中,继而流向荒漠区,引起荒漠区表层土壤盐分大幅升高。水位调控后,灌溉对农田区表层土壤脱盐效果更好,盐分随灌溉水向下运移更深。同时,不仅农田区侧向流入荒漠区盐分减少,而且减少了浅层咸水进入荒漠区包气带土壤中的盐分,有效缓解了荒漠区表层土壤聚盐效应。     

基于GA-BP神经网络的加速工况车内声品质研究

遴选出15辆乘用车三挡全油门加速工况车内噪声,选择专业评审者进行主观评价试验,选择具有噪声时变特征的4个客观评价参量,基于GA-BP神经网络建立精准的预测模型,同时将用该模型与多元线性回归模型得出的结果进行对比。研究表明,GA-BP神经网络模型更适合描述车内噪声品质评价的复杂性和非线性,可以获得更好的预测结果,可较大程度的提高预测精度。     

The reconstruction of fossil planation surface in China

On the basis of results of relative subjects, the fossil planation surface has been discussed by the authors from the point of geomorphologic view. The discussion contents included the characteristic information, research methods, paleotopography (gradient and altitude) and other problems about fossil planation surface. The recognition and reconstruction of fossil planation surface mainly rely on the following characteristic information: ( i ) the character of erosion unconformity surface; (ii) the paleo-weathering crust and residual deposits; (iii) the paleo-karst and filled deposit in the paleo-karst under the unconformity surface,and (iv) the character and environment of sediment above the unconformity surface. According to the above-mentioned characteristic information, the authors recognized and reconstructed two stages of fossil planation surface on Paleo-land of North China and Yangtze Paleo-land. These two fossil planation surfaces formed from Middle Ordovician to Lower Carboniferous and from Lower Permian to Upper Permian respectively. The paleo-gradient of fossil planation surface changed within 0.31‰-1.32‰, mostly less than 1.0‰. According to the developing depth of paleo-karst, the authors considered that in Suqiao buried-hill region of Paleo-land of North China, the paleo-altitude is 300 m or so above paleo-sea-level. The authors hope that the research is in favor of discussion about rising scale and process of the Tibetan Plateau. Besides, the research of fossil planation surface can provide a theoretical base for relative research,such as the reconstruction of paleoenvironment, the evolution and drift of paleo-continent, the formation and distribution of weathering ore deposits, the reservior and prospection of oil and gas, etc.     

AC2 and AC4 proteins of <Emphasis Type="Italic">Tomato yellow leaf curl China virus</Emphasis> and <Emphasis Type="Italic">Tobacco curly shoot virus</Emphasis> mediate suppression of RNA silencing

Tomato yellow leaf curl China virus Y10 isolate (TYLCCNV-Y10) alone could systemically infect host plants such as Nicotiana benthamiana without symptoms. In contrast, Tobacco curly shoot virus Y35 isolate (TbCSV-Y35) alone induces leaf curl symptoms in N. benthamiana. When inoculated into transgenic N. benthamiana plants expressing GFP gene (line 16c), TYLCCNV-Y10 neither reverses the established GFP silencing nor blocks the onset of GFP silencing. In contrast, TbCSV-Y35 can partially reverse the established GFP silencing and block the onset of GFP silencing in new leaves. In the patch co-infiltration assays, the AC2 and AC4 proteins of TYLCCNV-Y10 and TbCSV-Y35 could suppress local GFP silencing and delay systemic GFP silencing, suggesting that they are suppressors of RNA silencing. Comparison of the accumulation levels of GFP mRNA in the co-infiltration patches showed that Y10 AC2 and Y35 AC2 proteins had similar efficiency for suppression of RNA silencing. However, Y35 AC4 protein functioned as a stronger suppressor of RNA silencing than Y10 AC4 protein. There-fore, the pathogenicity difference between TbCSV-Y35 and TYLCCNV-Y10 may be related to the functional difference in their AC4 proteins.     

Van der Waals流体的大时间行为

相关液气相变的研究,主要研究一维混合型偏微分方程组初值问题的解关于时间的渐近性质。证明了积分意义下初始状态的平均密度决定了系统的大时间行为。     

色彩与质感——关于建筑的色彩设计

从色彩与质感的关系入手,分析了色彩在表达造型方面的特点;并由此总结出了建筑色彩设计的一般规律与特点.