我国货币供应时序结构的奇异谱分析

时间序列的结构分析是深入研究原始序列的重要前提。应用奇异谱分析并以极大熵谱估计为辅助,对我国广义货币供应量M2进行时间序列结构分析,结果显示:改革开放以来,我国广义货币供应量M2除了趋势项外,还具有周期分别约为10年、4～5年和3年,方差解释能力依次为23.22%、7.48%和3.44%的主周期波动成分;所有的周期波动成分的振幅均随时间而增大;长期趋势在改革开放前期增长速度较慢,而在中后期增长速度较快。     

基于支持向量机的云烟87烟叶成熟度高光谱遥感识别

利用烟叶光谱反射率数据研究烟叶的成熟度是将高光谱遥感探测技术应用于烟叶成熟采收的前提.对生理成熟期内云烟87的中部叶成熟度进行了研究,研究是从提取和分析烟叶高光谱信息的角度上进行的.基于提取到的反映烟叶成熟度的光谱特征和支持向量机这一基于数据的小样本学习方法,建立了识别烟叶成熟度的数学模型,这个数学模型是由支持向量机生成的2个最优决策超平面,一个将初熟类烟叶和适熟类烟叶分开,另一个将适熟类烟叶和过熟类烟叶分开,且分类精度均在90％以上.     

Application of the Multicomponent Spectral Fitting Algorithm in the Estimation of the Correct Value of Phosphorus determined by ICP OES in Soil Samples

ABSTRACT

Phosphorus (P) determination by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) in soil extracts is affected by copper (Cu) content and may lead to misinterpretation of the results. In this study, Multicomponent Spectral Fitting (MSF) method for the quantitative determination of P in the presence of Cu was tested. Phosphorus determination by UV/Vis molecular absorption spectrometry (COL) was free from copper interference. Phosphorus determination by ICP OES at wavelengths of 213.618 and 214.914 nm without use of MSF were subject to interference when Cu concentration was greater than 1.5 and mg L^?1 and 3.5 mg L^?1, respectively. When the P: Cu ratio in solution was 1:1 and 2:1, on average, there was no significant difference between the P determined by COL and by ICP-OES using MSF. In matrices containing Cu, it is indicated to use the P spectral line at 214.914 nm because it was less sensitive to Cu concentration than spectral line at 213.618 nm.     

奶牛产奶量测量系统设计

为了快速、准确地获取奶牛产奶量数据,避免目前常用的间接测量方法产生的误差,设计了基于质量计量的奶量采集系统。该系统通过在奶罐下安置基于压力传感器的质量称量机,将压力产生的模拟电信号通过A/D转换模块转变为数字电信号,再经分级处理从而获取牛奶质量数据,并直接上传至上位机。上、下位机之间通过CAN总线连接,基于自主协议进行相互通信。经多次测试表明,在5～35kg范围内该系统的测量误差可以控制在6%以下,且具有采集速度快、容错性强的特点。     

番茄叶片和果实热容量的热平衡测定方法

为了分析植物器官体温形成机制的需要,即在植物与环境间热平衡分析时,有准确的植物器官热容量参数,该文采用热平衡法测定了番茄叶片和果实的热容量参数。考虑胁迫生态环境植物传热分析问题,也选择了侧柏等生态恢复先锋树种,以及作为参照的肉质植物芦荟的热容量参数。结果表明,番茄叶片热容为3253.7±97.10J/(kg℃),与针叶植物侧柏和肉质叶植物芦荟叶片的热容相近;番茄果实热容为3517.4±68.50J/(kg℃)。热平衡法可以用来测定植物器官的热容量;其热容量均低于水的热容量。对前人用热平衡法测定生物质热物性参数的方法,进行了改进和完善。该文既为其他生物质的热容量测定提供了试验方法,也为植物气候空间研究提供了热物性参数基础数据。     

低压宽温状态下气体流量的动态测量方法

针对气体绝对压力小于40kPa的低压、宽温(-70～+80℃)状态下流量的测量,目前仍无简便有效的质量流量测量手段的问题,该文基于动态平衡原理提出了一种流量测量方法,设计了一套流量标定装置,其原理为低压、宽温状态下,流经调节阀的流量取决于阀前、后压力、阀门开度、气流温度4个变量。通过对由流量标定装置采集的原始数据样本的分析,利用BP神经网络方法建立了流量与阀前、后压力、阀门开度、气流温度的关系表达式。试验结果表明模型计算值与实测流量偏差小于1.8%,验证了该文所提出的流量测量方法有效性。     

Development and experiment of handheld digitalized and multi-functional forest measurement gun

为了实现森林的数字化、多功能、精准计测,该文研制了一种数字化多功能电子测树枪,该设备以MEMS（micro-electro-mechanical systems）测角传感器、激光测距传感器、电子罗盘等主要硬件为基础,通过测量距离、倾角、磁方位角3个参数,基于三角函数原理,嵌入操作软件,实现了树高测量、林分平均高测量、株数密度测量、角规绕测、任意高度直径测量、基本测量6项功能。并将该设备在河南省、内蒙古等地林场进行了试验,试验结果表明,树高测量精度最高,达99.39%,林分平均高测量精度最低,为94.97%,其他功能精度都在95%以上,可以满足林业外业调查的需要。     

基于抽样调查地块实测数据的省级水稻单产遥感估算

利用统计局抽样调查地块实割实测标准单位面积产量数据及空间位置信息,在研究水稻种植区MOD09GA、MYD09GA EVI （enhanced vegetation index）数据结合使用可行性分析的基础上,进行湖南省省级水稻单产遥感估算。结果表明：在水稻种植区,水稻生长期间有超过50%、85%、95%的MOD09GA与MYD09GA EVI偏差绝对值分别小于0.03、0.08、0.1。水稻遥感估产模型以二次非线性模型或回归模型精度较高,且时相集中在水稻生长的孕穗期到抽穗期。在省级水平上,与实测值相比,基于统计局统计抽样调查地块实割实测标准单位面积产量数据的水稻单产遥感拟合结果相对误差小于2%,预测结果的相对误差接近5%,且实测值与模拟值集中分布在1∶1线附近,说明预测结果与统计值在空间分布上具有较好的一致性。     

Effects of cuvette surface material on ammonia‐, nitrous oxide‐, carbon dioxide‐, and methane‐concentration measurements

Closed‐chamber systems are commonly used to determine gaseous C and N emissions from agricultural soils. We investigated the effects of eight cuvette surfaces on two standard gas concentrations of NH₃, N₂O, CO₂, and CH₄ under laboratory conditions. Cuvette surface materials differentially affected gas adhesion or recovery as a function of the type and the concentration of the gases. Given the strong effects on results of gas measurements in closed‐chamber systems, both the type and the concentration of the measured gases need to be considered in selecting cuvette surface materials.     

Long term and seasonal courses of leaf area index in a semi-arid forest plantation

Effective leaf area index (LAI_e) in the semi-arid Pinus halepensis plantation, located between arid and semi-arid climatic zones at the edge of the Negev and Judean deserts, was measured bi-annually during four years (2001-2004) and more intensively (monthly) during the following two years (2004-2006) by a number of non-contact optical devices. The measurements showed a gradual increase in LAI_e from ∼1 (±0.25) to ∼1.8 (±0.11) during these years. All instruments, when used properly, gave similar results that were also comparable with actual leaf area index measured by litter collection and destructive sampling and allometric estimates. Because of the constraint of clear sky conditions, which limited the use of the fisheye type sensors to times of twilight, the fisheye techniques were less useful. The tracing radiation and architecture of canopies system, which includes specific treatment of two levels of clumpiness of the sparse forest stand, was used successfully for the intensive monitoring. The mean clumpiness index, 0.61, is considered representative for the specific environment. Finally, the LAI_e measurements at the start of each season were used to constrain phenology-based estimates of annual LAI_e development, resulting in a continuous course of LAI_e in the forest over the five-year period. Intra-seasonal LAI_e variation in the order of 10% of total LAI_e predicted by the model was also observed in the intensive TRAC measurements, giving confidence in the TRAC system and indicating its sensitivity and applicability in woodlands even with low LAI_e values. The results can be important for forest management decision support as well as for use in evaluation of remote sensing techniques for forests at the lowest range of LAI_e values.