层序古地理背景下河南省二_1煤聚集规律研究

对河南省晚石炭世-早二叠世含煤岩系(太原组中部碎屑岩段、上部灰岩段和山西组二1煤层段、大占砂岩段)进行层序分析,共识别出以胡石砂岩底面、二1煤底面、大占砂岩底面和香炭砂岩底面为代表的4个层序界面,将该层段含煤岩系划分为3个三级层序。通过对层序S1和层序S3岩相古地理图和二1煤厚度等值线图耦合分析发现,障壁岛-潟湖沉积环境为二1煤的聚集提供一个较好的前期环境,分流间湾沉积环境为二1煤的保存提供一个较好的后期环境,而分流河道对二1煤的保存起到了破坏性的作用。     

http://www.sciencedirect.com/science/article/pii/S1674987111001320

Ectomycorrhizal fungi,a group of widcspread symbiotic fungi with plant,obtain carbon source from trees and improve plant mineral nutrient uptake with their widespread hyphal network.Ectomycorrhizal fun...     

http://www.sciencedirect.com/science/article/pii/S1674987111001290

The Three Gorges Dam(TGD) of the Yangtze River.China,is one of the largest irrigation and hydroelectric engineering projects in the world.The effects of huge man-made projects like TGD on fauna and macrophyte are obvious,mainly through changes of water dynamics and flow pattern;however, it is less clear how microorganisms respond to such changes.This research was aimed to examine differences in microbial diversity at different seasons and locations(in front of and behind the TGD).In addition, differences between particle-attached and free-living communities were also examined.The community structures of total and potentially active microorganisms in the water columns behind and in front of the TGD were analyzed with the DNA- and RNA-based 16S rRNA gene phylogenetic approaches over three different seasons.Clone libraries of 16S rRNA genes were prepared after amplification from extracted DNA and.for some samples,after preparing cDNA from extracted rRNA.Differences were observed between sites at different seasons and between free-living and particle-attached communities.Both bacterial and archaeal communities were more diverse in summer than in winter, due to higher nutrient levels and warmer temperature in summer than in winter.Particle-attached microorganisms were more diverse than free-living communities,possibly because of higher nutrient levels and heterogeneous geochemical micro-environments in particles.Spatial variations in bacterial community structure were observed,i.e..the water reservoir behind the TGD(upstream) hosted more diverse bacterial populations than in front of the dam(downstream),because of diverse sources of sediments and waters from upstream to the reservoir.These results have important implications for our understanding of responses of microbial communities to environmental changes in river ecosystems affected by dam construction.     

Sobol’ sensitivity analysis of parameters in the common land model for simulation of water and energy fluxes

The water and energy transfer of land surface is complex due to its large spatial and temporal variability. The modeling and simulation is an important means to study land water and energy transfer, but most selection and analysis of model parameters are empirical and qualitative. This paper has proposed a method of quantitatively identifying the most influential parameters of Common Land Model through Sobol?? sensitivity analysis. Considering sensible heat flux as the model output, the first order and total sensitivity indices of 25 model input parameters are estimated using an improved Sobol?? method. The simulated results are resampled using a bootstrapping method and the corresponding sensitivity indices are calculated. Confidence intervals for the bootstrapping sensitivity indices are estimated by using a percentile method. The results show that the parameters phi0 and porsl are the most important parameters, followed by ref(2,1), tran(2,1) and bsw. Five out of 25 parameters need to have an accurate evaluation, while the other parameters are fixed to a certain value. The sensitivity indices of parameters phi0 and porsl are decreasing after precipitation, while the sensitivity indices of parameters tran(2, 1) and ref(2, 1) are increasing after precipitation.     

导航卫星钟差预报的Elman神经网络算法研究

针对卫星钟差不能被精确模型化的问题,将具有较强记忆功能和强大计算能力的Elman神经网络运用到卫星钟差预报中,提出适用于卫星钟差预报的Elman模型。首先对原始钟差数据进行一次差处理,然后选择合适的神经网络结构建立预报效果最佳的Elman钟差预报模型,最后选用国际GNSS服务（IGS）提供的精密钟差数据进行GPS卫星钟差预报,并与二次多项式模型、附加周期项的多项式模型和灰色系统模型进行对比分析。结果表明,Elman模型进行1 d、7 d和30 d钟差预报的精度得到显著提高,分别达到亚ns、ns和μs级,表明该模型的钟差预报性能优于3种常用模型,在卫星钟差预报中具有可行性。     

光及补料条件对室内管道光反应器中三角褐指藻生长和岩藻黄素积累的影响

【目的】制备富含岩藻黄素的三角褐指藻(Phaeodactylum tricornutum)生物质。【方法】采用470 L室内管道光生物反应器系统,研究自养培养下光源、调光策略、补料培养操作条件对于细胞生长、生物量浓度和岩藻黄素积累的影响。【结果】在采用LED灯、梯度提升照度及重复补料半连续培养模式下,三角褐指藻细胞密度、生物量和岩藻黄素产率最高分别可达3.16×10⁷mL^-1、1.64 g/L和1.90 mg/(L·d),分别是日光灯为光源条件下的2.77倍、3.09倍和2.38倍(P<0.01)。【结论】在管道光生物反应器中获得的自养培养条件,可强化三角褐指藻生物量和岩藻黄素积累,为三角褐指藻积累岩藻黄素的室内可控规模化技术开发提供指导。     

基于典型物候特征的MODIS-EVI时间序列数据 农作物种植面积提取方法 —小区域冬小麦实验研究

利用MODIS植被指数时间序列这一特性,以北京市通州及周边为实验区,冬小麦种植面积为研究对象,提出 了农作物种植面积指数模型(Pan-CPI模型)的概念,并构造了冬小麦特征物候期植被指数与种植面积的定量函数关系, 通过样区TM影像求解关键参数,对研究区冬小麦种植面积测量方法进行了试验研究。研究结果表明：(1)Pan-CPI模 型能够很好地反映特定目标农作物种植面积状况,为基于植被指数时间序列影像识别农作物种植面积提供了新方法; (2)精度分析结果表明：Pan-CPI模型具有很高的稳定性,且不受样本变化的影响,只要达到满足模型计算的样本量(如： 5%),多次测量结果间具有很好的一致性。选取MODIS 6×6像元大小的窗口时,TM样本的复相关系数(R2)稳定在0.85 左右,与TM结果比较,窗口相对精度稳定在95%左右,区域精度稳定在92%以上,经调整的区域精度高达96%以上; (3)对于种植结构复杂、目标作物种植破碎的地区,Pan-CPI模型可以充分利用MODIS植被指数时间序列的优势,有效改 善TM单时相和多时相提取信息因时相缺失无法表征作物变化的不足。     

导航用重力梯度基准图构建方法的比较研究

基准图是重力梯度辅助导航实用化研究的关键技术,由于依靠实测构造大范围基准图还需要较长时间,理论模型逼近重力梯度开始成为可行的构图方法。系统研究了一种基于自由空间异常或布格异常数据的构图方法,避免了相关研究构建梯度图时较少考虑标准测量数据,构图结果物理意义不明确和缺乏实用性的缺点。以重力归算理论推导了构图方法原理,然后用频域算法实现构图过程中两个关键计算过程,通过算例分析了构图效果。所构基准图数值、轮廓等关键特征均与实测重力梯度吻合较好,证明了该方法在重力梯度辅助导航基准图构建中的实用价值。     

不同校正方法对RTK测图精度的影响

基于RTK技术的原理和方法进行测量实验,将RTK测量数据与GPS静态定位数据进行分析对比,探讨了不同的校正方法、测量距离等因素对RTK测量精度的影响,从而得出RTK的作业精度和实际作用范围,为RTK更好地在工程测量中应用提供了参考。     

北斗系统及GNSS多星座组合导航性能研究

针对北斗、GPS、GLONASS和GALILEO等单星座系统定位中存在的定位精度不足、可见星不多、定位可靠性不强等问题,研究了一种利用北斗、GPS、GLONASS和GALI—LEO多星座信息在统一坐标系中采用最小二乘法进行组合导航定位的方法。仿真结果表明：北斗与GPS双系统的定位精度优于单纯的北斗系统精度,而采用北斗／GPS／GLONASS／GALILEO多星座组合导航定位能够有效提高用户的定位精度和可靠性,研究成果对北斗系统的精度验证和多星座接收机的实现具有参考意义。