不同香型烟区地形特征的比较研究

烤烟是一种内在质量对生态条件十分敏感的经济作物.地形特征是作物生长所需的重要的生态条件之一,影响着地表物质和能量的再分配,而这些会导致土壤类型的分异和土壤性质的不同,进而影响到土壤中作物的品质,以及作物对光、热和水分等条件的接收差异.通过对我国浓香型典型烟区和清香型典型烟区的野外实地调查,结合DEM图,研究浓香型烟区和清香型烟区的地形特征,及其对烟叶香型风格的影响.     

缆系海底观测网电力系统结构与拓扑可靠性

缆系海底观测网可持续提供充裕电能和通信带宽给大量海底科学仪器.基于可靠性和经济性的原则,分析得观测网电力系统适合采用负高压单极直流输电、以海水作为电流回路、海底负载并联供电和级联式高频直流变换的总体方案,并以此为基础设计了观测网的物理架构.根据观测网的特点,总结了海底电力系统适合采用的几类典型拓扑,并以水下基站平均供电可靠度为可靠性指标,计算并比较了这些典型拓扑的可靠性,可为观测网的拓扑规划提供依据.进一步设计了海底电力系统的运行模式,以提高观测网的容错能力.研究结果可为国家未来建设大规模观测网提供参考.     

KH-4B卫星数据在城镇周边活动断层解译中的应用

地震的发生与活动断层的发育密切相关,城镇周边活动断层调查对于合理地规划城市和抗震设防、减轻城市可能遭遇的地震损失具有重要意义。遥感技术可以为活动断层调查提供快速有效的技术手段。然而,受城镇化及人类活动改造的影响,新成像的遥感数据在城镇及周边活动断层调查中发挥的作用有限;而成像于20世纪60年代的美国侦察卫星KH-4B影像较好的保存了活动断层运动形成的各种微地貌单元,这些地貌现象受人类活动改造较小。利用该卫星数据对郯庐断裂带江苏段分支之一的新沂-新店断裂进行解译研究,分析该断裂带的几何展布特征,介绍KH-4B数据在活动构造填图和定量研究中的应用,对该数据应用于活动断层的效果进行了评价,收到了良好的效果;并系统总结了一套数据处理与活动断层提取技术流程。     

神经网络模型度量地形对实际行驶排放的影响

由于难以将行驶路线地形的影响从实际行驶排放(real driving emission,RDE)试验的其他试验边界的影响中独立出来,提出采用神经网络输入变量重要性算法以定量评估行驶路线地形试验边界对RDE试验的影响强度。以重庆地区RDE试验的37 256个数据窗口排放样本为基础,采用因子分析方法缩减数据并消除试验边界之间的信息重叠,建立神经网络模型预测污染物排放,并计算输入变量相对重要性占比。结果表明,行驶路线地形试验边界在二氧化碳(CO₂)排放中起主导作用,它的相对重要性远大于行程动力学试验边界。对于一氧化碳(CO)、颗粒数量(particle number,PN)、氮氧化物(NO_x)污染物排放,地形因素的影响力仍不可忽视,特别是在车辆高速行驶条件下,它对车辆行驶排放的影响与行程动力学因素大致相当。总体而言,在现有排放标准体系中,行驶路线地形试验边界对RDE试验的影响被严重低估。     

浅海水下地形SAR成像中松弛率参数的研究

松弛率是浅海水下地形SAR成像中的关键参数。首先对水下地形的SAR成像机制,及其中的松弛率进行了理论推导;然后对松弛率进行了实验比较。由此获得的结论对实际应用具有指导意义。     

深海两千五百米——加拉帕戈斯海底热液探索

30多年前(1975年),人们在位于东太平洋的加拉帕戈斯海底首次发现了正在活动的海底热液,以及与此相伴的热液生物群落。这个发现震撼了当时的科学界,对以后地学、生物学的发展起到了巨大的影响,以至在今天人们还很难断言这一发现最终的意义。在下面这些不连贯的笔记中,作者记录了在2005年随同科考船亚特兰蒂斯(RV/At-lantis)及深潜器阿尔文(Alvin)在这一海域的工作经历,以此纪念30多年前的这一科学发现。     

EVVA源离子束合成镧硅化物

用MEVVA离子源将La离子注入到单晶硅中形成掺杂层 ,用XRD ,SEM分析了掺杂层的物相和表面形貌 .分析结果表明 ,在强流离子注入后 ,掺杂层中有硅化物形成 ,且形成相的种类与注量、束流密度及后续热处理条件密切相关 .对La硅化物的形成过程进行了讨论 .     

Demographic characteristics,seasonal range and habitat topography of Balkan chamois population in its southernmost limit of its distribution (Giona mountain,Greece)

The annual range of Balkan chamois (Rupicapra rupicapra balcanica) in Giona mountain was found to be 5502 ha, with a low population density (2 individuals/100 ha). Seasonal range patterns varied significantly, with a minimum extent in summer and a maximum in winter (30% and 79% of the annual range, respectively). Summer stress and the rutting period might be associated with the observed aggregated distributions during the summer and autumn (core areas of 28% and 22% of seasonal ranges, respectively, defined after the Fixed Kernel Density Estimator). Chamois were found to use significantly lower altitude habitats in winter (1212 m) than in summer (2223 m), and significantly steeper slopes in winter (35°); aspect was not found to have a significant effect on habitat use. Population structure consisted of kids (21%), yearlings (8%), females (35%) and males (36%). Conservation management for the species should consider poaching, livestock competition and global warming.     

基于GNSS-A的海底目标高精度定位算法研究

为提高海底目标垂直方向的定位精度,在分析全球导航卫星/声学定位(Global Navigation Satellite System-Acoustic, GNSS-A)基本原理的基础上,提出基于动态观测的海底目标声学定位算法。针对动态观测中产生的双程传播时延问题,将其发射和接收过程分别考虑,并利用最小二乘(Least Squares, LS)法解算圆形对称观测数据,消除绝大部分系统误差和粗差对水平定位精度的影响;结合水平解算结果、高精度声学测距信息和实测声速剖面信息,开展声线跟踪(Sound Ray Tracking, SRT)并构造迭代,进一步减弱垂直方向误差,提高海底目标点的垂直定位精度。南海实验证明,采用本文方法可以有效减小声速误差对测距精度的影响,明显提高海底目标在垂直方向上的定位精度。     

Magnetic recording of the Cenozoic oceanic crustal accretion and evolution of the South China Sea basin

We review and discuss some of the recent scientific findings made on magnetic data in the South China Sea (SCS). Magnetic anomalies bear extremely rich information on Mesozoic and Cenozoic tectonic evolution. 3D analytical signal amplitudes computed from magnetic anomalies reveal very precisely relict distributions of Mesozoic sedimentary sequences on the two conjugate continental margins, and they are also found very effective in depicting later-stage magmatism and tectonic transitions and zonation within the SCS oceanic crust. Through integrated analyses of magnetic, gravity and reflection seismic data, we define the continent-ocean boundary (COB) around the South China Sea continental margin, and find that the COB coincides very well with a transition zone from mostly positive to negative free-air gravity anomalies. This accurate outlining of the COB is critical for better tracing magnetic anomalies induced by the oceanic crust. The geometrically complex COB and inner magnetic zonation require the introduction of an episodic opening model, as well as a transform fault (here coined as Zhongnan Fault) between the East and Southwest Sub-basins, while within the East and Southwest Sub-basins, magnetic anomalies are rather continuous later-ally, indicating nonexistence of large transform faults within these sub-basins. We enhance magnetic anomalies caused by the shallow basaltic layer via a band-pass filter, and recognize that the likely oldest magnetic anomaly near the northern continental margin is C12 according to the magnetic time scale CK95. Near the southern continental margin, magnetic anomalies are less recognizable and the anomaly C12 appears to be missing. These differences show an asymmetrical opening style with respect to the relict spreading center, and the northern part appears to have slightly faster spreading rates than to the south. The magnetic anomalies C8 (M1 and M2, ~26 Ma) represent important magnetic boundaries within the oceanic basin, and are possibly related to changes in spreading rates and magmatic intensities. The magnetic evidence for a previously proposed ridge jump after the anomaly C7 is not clear. The age of the Southwest Sub-basin has yet to be further examined, most favorably with deep-tow magnetic surveys and ocean drilling. Our magnetic spectral study shows that the shallowest Curie points are located around the eastern part of the Southwestern Sub-basin, whereas within the East Sub-basin Curie depths are smaller to the north of the relict spreading center than to the south. This pattern of Curie depths is consistent to regional heat flow measurements and later-stage volcanic seamount distributions, and we therefore reason that Curie-depth variations are closely associated with later-stage magmatism, rather than with crustal ages. Although magnetic anomalies located around the northern continent-ocean transition zone (COT) are relatively quiet, this area is not a typical magnetic quiet zone since conceptually it differs markedly from an oceanic magnetic quiet zone. The relatively quiet magnetic anomalies are seemingly associated with a shallowing in Curie isotherm and thinning in magnetic layer, but our comprehensive observations suggest that the well-preserved thick Mesozoic sedimentary rocks are major causes for the magnetically quiet zone. The high similarities between various low-pass filtered marine and air-borne magnetic anomalies and satellite magnetic anomalies clearly confirm that deeper magnetic sources (in the lower crust and the uppermost mantle) have contributions to long-wavelength surface magnetic anomalies in the area, as already inferred from magnetically inversed Curie depths. The offshore south China magnetic anomaly (SCMA) becomes more prominent on low-pass filtered marine and air-borne magnetic anomalies and satellite magnetic anomalies, indicating very deeply-buried magnetic sources beneath it.