Influence of the interaction between light intensity and CO2 concentration on productivity and quality of spinach (Spinacia oleracea L.) grown in fully controlled environment

The effects of the factorial combination of two light intensities (200 and 800 μmol m⁻² s⁻¹) and two CO₂ concentrations (360 and 800 ppm) were studied on the productivity and nutritional quality of spinach (Spinacia oleracea L.) grown under controlled environment. After 6 weeks within a growth chamber, spinach plants were sampled and analyzed for productivity and quality. There were no statistically significant interactions between the effects of light and CO₂ for all of the variables studied, except for the nitrate and oxalic acid content of the leaves. High light and high CO₂ independently one from the other, promoted spinach productivity, and the accumulation of ascorbic acid, while their interactive effect limited the accumulation of nitrate and oxalic acid in the spinach leaves. The results highlight the importance of considering the effects of the interaction among environmental variables on maximizing production and the nutritional quality of the food when cultivating and modeling the plant response in controlled environment systems such as for bioregenerative life support.     

影像增强器DR/CT系统像场畸变快速校正

以XRS-152/153影像增强器DR/CT成像系统为研究对象,在分析其输出像场畸变特性的基础上,从校正精度和校正实时性要求出发,采用空间坐标多项式变换方法进行畸变校正.同时,为了解决畸变校正算法计算量大、运算速度慢的问题,利用可编程图形处理单元(GPU, Graphic Processing Unit)并行计算和高速浮点计算特性,将图像映射为GPU中的纹理,采用多线程并行计算,使得校正算法在GPU中加速执行.实验结果表明,本方法能有效实现畸变图像的校正,GPU加速方法可以在不损失图像信息的前提下,实现实时校正.     

Testing Modified Newtonian Dynamics with LISA Pathfinder

We suggest that LISA Pathfinder, a technology demonstrator for the future gravitational wave observatory LISA, could be used to carry out a direct experimental test of Modified Newtonian Dynamics (MOND). The LISA Pathfinder spacecraft is currently being built and the launch date is just a few years away. No modifications of the spacecraft are required, nor any interference with its nominal mission. The basic concept is to fly LISA Pathfinder through the region around the Sun-Earth saddle point, in an extended mission phase, once the original mission goals are achieved. We examine various strategies to reach the saddle point, and find that the preferred strategy, yielding relatively short transfer times of just over 1 year, probably involves a lunar fly-by. LISA Pathfinder will be able to probe the intermediate MOND regime, i.e. the transition between deep MOND and Newtonian gravity. We present robust estimates of the anomalous gravity gradients that LISA Pathfinder should be exposed to, based on MONDian effects as derived from the Tensor-Vector-Scalar (TeVeS) theory. The spacecraft speed and spatial scale of the MOND signal combine in a way that the spectral signature of the signal falls precisely into LISA Pathfinder’s measurement bandwidth. We find that if the gravity gradiometer on-board the spacecraft achieves its currently predicted sensitivity, these anomalous gradients could not just be detected, but measured in some detail.     

西宁曹家堡机场二期建设期间风沙现象特殊性的统计分析

针对西宁曹家堡机场2010、2011年风沙现象迅速增多的原因进行了详细的统计分析,得出了机场二期建设期间风沙现象的特点,并总结了合理的观测方法.     

以网络输出为导向的任务型教学在大学英语听说课程的实施与反思

本文阐述了基于以网络输出为导向的任务型教学模式的基本定义、特点,教学步骤和设计理念。通过讨论此教学模式在大学英语听说教学中的应用,总结和反思教学实践,证明基于网络环境下以输出为导向的任务型教学是一种行之有效的教学模式,能切实有效地优化英语听说课堂教学。     

高职英语专业学生英语记忆策略实证调查研宄

本研究以武汉商业服务学院商务英语专业学生为对象,对其英语学习策略和九种记忆策略使用情况分别进行了调查研究。结果表明,学生使用频率最高的是补偿策略,最低的是记忆策略。在九种记忆策略中,学生使用频率最高的是联想策略,最低的是借用肢体语言记忆策略。     

激光多普勒测速系统自适应阈值检测算法

信号检测是激光多普勒测速(LDV)系统实现高精度的关键技术,针对LDV中微弱多普勒信号的检测,本文从噪声在频域中的统计特性出发,对多普勒信号进行带阻滤波,结合雷达的恒虚警(CFAR)检测技术,设计了基于频域的单元平方和自适应阈值检测算法以解决在低信噪比(SNR)的环境中LDV的信号检测问题,提高LDV的信号探测能力,同时降低其虚警概率。仿真与实验的结果表明:该算法与固定阈值相比可以在SNR为-12 d B时实现信号的完全检测,保持低虚警概率,运算简单,工程适用性强。     

考虑磁滞效应的电抗器二维电磁场计算

将JA模型与电磁场数值分析方法相结合,在考虑铁心的磁滞效应的情况下,推导出电磁场的有限元计算模型。分别采用基本磁化曲线和磁滞回线两种不同的方法对电抗器的电磁场进行仿真计算。研究结果表明磁滞现象对电抗器电磁场的计算影响较大,因此考虑磁滞效应的电磁场数值计算模型,为进一步研究电抗器的发热问题奠定了理论基础。     

重力姿轨耦合效应引起的太阳能电站轨道共振

以任意相控阵天线式空间太阳能电站为研究对象,主要研究了其在轨运行过程中受到的重力姿轨耦合效应对其轨道运动的影响。首先,通过Hamilton原理建立起考虑重力姿轨耦合效应时的姿态运动和轨道运动的方程。其中,任意相控阵天线式空间太阳能电站被简化成刚体,它的重力势能以其结构尺寸和其轨道半径的比值为小量进行泰勒展开,并保留至二阶项。之后,采用解析的方法对方程进行分析,并发现当电站的姿态运动满足一定条件时,其轨道运动将会出现共振现象。此外,重力姿轨耦合效应还会引起空间太阳能电站轨道运动长期的漂移,通过选择合适的轨道运动初始条件可以消除漂移;而且,在一定条件下,重力姿轨耦合效应还会引起轨道运动的发散。最后,数值仿真结果验证了分析的正确性。     

高职英语教师科研能力现状及对策分析

提高教师科研能力,以科研带动教学,以科研提升师资队伍的整体水平,已经成为高职院校实现自身发展的一大重要举措。本文调查了浙江省高职英语教师科研现状,并提出了高职英语改进科研现状的对策。