频谱激电法的发展与展望

从频谱激电法的发展概况﹑仪器系统、数学模型、反演方法及应用等方面,介绍了频谱激电法的研究现状。介绍了频谱激电法目前常用的仪器系统:SIP?FUCHSII和V8,数据模型主要有:Cole-Cole、常相位角模型CPA、普通化的Cole-Cole模型和理论模型SNP。反演方法简要介绍了几种常用算法,反演算法也由一维、二维发展到三维。列举了频谱激电法近年来在矿产资源、水资源调查等多个领域的应用概况,展望了频谱激电法的发展方向:(1)同时考虑激电效应和电磁效应的三维电磁场正演计算技术是研究的前沿和热点;(2)频谱激电法对有机污染的探查成为未来应用研究的新领域。     

5－（4－羧基苯偶氮）－8－（对甲苯磺酰氨基）－喹啉与金显色反应研究及应用

以８－氨基喹啉为母体，合成了新试剂５－（４－羧基苯偶氮）－８－（对甲苯磺酰氨基）－喹啉（ＣＰＴＳＱ），研究了它与Ａｕ的显色反应，在ＣＴＭＡＢ存在下，于ｐＨ１０～１３的ＮａＯＨ介质中，ＣＰＴＳＱ与Ａｕ形成２：１紫蓝色络合物，最大吸收峰位于６１０ｎｍ，摩尔吸光系数１．０×ｌ０５Ｌ·ｍｏｌ－１·ｃｍ－１，Ａｕ含量在０～１．２ｍｇ／Ｌ内符合比尔定律。方法选择性好，灵敏度高，操作简便，已用于金矿石样品中Ａｕ的测定，结果满意。     

Mapping degraded grassland on the Eastern Tibetan Plateau with multi-temporal Landsat 8 data — where do the severely degraded areas occur?

The Tibetan Plateau in Western China is the world’s largest alpine landscape, sheltering a rich diversity of native flora and fauna. In the past few decades, the Tibetan Plateau was found to suffer from grassland degradation processes. Grassland degradation is assumed to not only endanger biodiversity but also to increase the risk for natural hazards in other parts of the country which are ecologically and hydrologically connected to the area. However, the mechanisms behind the degradation processes remain poorly understood due to scarce baseline data and insufficient scientific research.We argue that remote sensing data can help to better understand degradation processes and patterns by: (1) identifying the distribution of severely degraded areas and (2) comparing the patterns of key spatial attributes of the identified areas (altitude above sea level, aspect, slope, administrative districts) with existing theories on degradation drivers. Therefore, we applied four Landsat 8 images covering large portions of the three counties Jigzhi, Baima and Darlag in the Eastern Tibetan Plateau. The dates of the Landsat scenes were selected to cover differing phenological stages of the ecosystem. Reference data were collected with a remotely piloted aircraft and a standard consumer RGB camera. To exploit the phenological information in the Landsat data as well as deal with the problem of cloud cover in multiple images, we developed a straightforward PCA-based procedure to merge the Landsat scenes. The merged Landsat data served as input to a supervised support vector machine classification which was validated with an iterative bootstrap procedure and an additional independent validation set. The considered classes were “high-cover grassland”, “grassland (including several stages of grassland vitality)”, “(severely) degraded grassland”, “green shrubland”, “grey shrubland”, “urban areas” and “water bodies”. Kappa accuracies ranged between 0.84 and 0.93 in the iterative procedure, while the independent validation led to a kappa accuracy of 0.76. Mean producer’s and user’s accuracies for all classes were higher than 80%, and confusion mainly occurred between the two shrubland classes and between the three grassland classes.Analysis of the slope, aspect and altitude values of the vegetation classes revealed that the degraded areas mostly occurred at the higher altitudes of the study area (4300–4600 m), with no strong connection to any specific slope or aspect. High-cover grassland was mostly located on sunny slopes at lower altitudes (less than 4300 m), while shrubland preferred shady, relatively steep slopes across all altitudes. These observations proved to be stable across the examined counties, while the proportions of land-cover classes differed between the examined regions. Most counties showed 5–7% severely degraded land cover. Darlag, the county located at the edge of the permafrost zone, and featuring the highest average altitude and lowest annual temperature and precipitation, was found to suffer from larger areas of severe degradation (14%).Therefore, our findings support a strong connection between degradation patterns and climatic as well as altitudinal gradients, with an increased degradation risk for high altitude areas and areas in colder and drier climatic zones. This is relevant information for pastoral management to avoid further degradation of high altitude pastures.     

Landsat 8全色影像阴影的扁平冰山出水高度提取

冰山出水高度是测量冰山厚度进而估算冰山体积的一个重要几何参数,是定量评估冰山对海洋的淡水输入量的基础。冬季冰山在海冰上成影且阴影较长,本文提出利用阴影测高模型高精度测量冰山出水高度的方法。试验选择2016年8月29日、9月7日和9月16日中心太阳高度角分别为5.43°、7.49°和11.01°的3期Landsat 8全色15 m影像,以独立扁平冰山为例,自动提取冰山在海冰上的阴影长度计算冰山出水高度,并利用不同时相同名成影点进行交叉验证评估测量精度。结果显示：阴影长度测量误差优于1个像元,在太阳高度角低于11.01°时,全色15 m影像提取的冰山出水高度均方根误差（RMSE）低于2.0 m,平均绝对误差（MAE）低于1.5 m。由此表明：在冬季低太阳高度角下,Landsat 8全色15 m影像可用于高精度测量冰山出水高度,具有大范围测量南极冰山出水高度的潜力。     

尼泊尔Ms8.1级地震中国西藏地区地震震害特征分析

2015年4月25日尼泊尔发生Ms8.1级地震,对我国西藏地区造成较大人员伤亡与房屋破坏,道路、通讯等生命线工程及水利等基础设施损坏严重。本文介绍了本次地震的基本情况,并在现场地震烈度调查和地震损失评估的基础上,对灾区震害情况进行了分析,给出了灾区房屋类别与破坏情况以及生命线系统与各行业的受损情况。通过分析此次地震的灾害特点,指出了灾区在抗震设防中存在的问题,最后提出应加大地震地质灾害的防治力度,科学编制恢复重建规划,加强防震减灾宣传,提高农牧民抗震设防意识,加强农牧区房屋建筑的指导和监管,减少地震人员伤亡和损失,促进西藏地区经济的和谐发展。     

On the Multiplicity of the O-Star Cyg OB2 #8a and its Contribution to the γ-ray Source 3EG J2033+4118

We present the results of an intensive spectroscopic campaign in the optical waveband revealing that Cyg OB2 #8A is an O6+O5.5 binary system with a period of about 21.9 days. Cyg OB2 #8A is a bright X-ray source, as well as a non-thermal radio emitter. We discuss the binarity of this star in the framework of a campaign devoted to the study of non-thermal emitters, from the radio waveband to γ-rays. In this context, we attribute the non-thermal radio emission from this star to a population of relativistic electrons, accelerated by the shock of the wind-wind collision. These relativistic electrons could also be responsible for a putative γ-ray emission through inverse Compton scattering of photospheric UV photons, thus contributing to the yet unidentified EGRET source 3EG J2033+4118. Based partly on data Obtained at the Observatoire de Haute-Provence, France.     

Palaeoecology of a late Allerød peat bed at Godøy,western Norway

A peat bed found under solifluction deposits on Godøya island, western Norway, accumulated during a few decades around 11 000 yr BP, at the end of the Allerød period of the Late Weichselian. Palaeoecological investigations showed a local vegetation succession on wet sand culminating in a mire community dominated by Carex nigra. Periodic flooding brought in sand and silt, which decreased as drainage was impeded sufficiently for standing water to develop. The surrounding terrestrial vegetation was dominated by Salix scrub, with some open heath and alpine habitats nearby. Apart from two aquatic species, the 29 insect taxa recorded are characteristic of alpine heaths, plant litter (under Salix scrub) and stream-sides. Their remains, together with the terrestrial plant macrofossils, were washed into the mire from nearby. Because the fossils are locally derived, the environmental reconstructions are of the actual conditions at Godøy at ca. 11 000 yr BP. Palaeotemperature estimates from beetles and plants are in agreement. The coleopteran estimates (Mutual Climatic Range Method) suggest mean July temperatures of 10–13°C, slightly cooler than today (13.5°), and January temperatures between +1 and ?10°C, similar to or much colder than today. Summer temperature estimates from individual plant taxa indicate that temperatures during the Allerød period were similar to today's, but estimates from the reconstructed vegetation and timber-line positions give estimates up to 3.5° cooler. Temperatures fell 2.5–7.5°C at the Younger Dryas. This abrupt and severe cooling initiated the solifluction processes on Godøya that buried the peat. The Godøy peat bed and its contained fossils provide a rare glimpse of Allerød biota and environments at the local (site) scale.     

典型风力条件及水力调度下太湖藻华高频时空动态监测

湖泊藻华问题已成为全球水生态环境领域面临的长期挑战,风力条件变化和引调水工程的水力调度能改变湖体水动力结构,对藻类的生长和聚集过程产生影响,进行该过程的精细化监测和机制分析对于湖泊藻华预报预警和应急处置具有重要意义。本研究基于Hiamwari-8/AHI卫星遥感高频监测数据,对比分析了归一化差异植被指数(NDVI)、增强植被指数(EVI)和浮游藻类指数(FAI) 3种不同指数对太湖藻华的反演效果,开展了典型风力条件下和水力调度下太湖藻华生消过程的持续监测分析。结果表明,FAI对藻华区域和非藻华区域的区分更加明显,其阈值提取的藻华面积与基于MODIS图像解译的藻华面积的相对误差最低,为-2.27%。当营养盐充足且水温持续保持在蓝藻大量生长增殖的阈值以上时,风力条件是导致太湖藻类迁移聚集的关键因子,风向主要影响藻类的水平迁移,使其进行方向性迁移并逐渐形成大面积藻华区域。风速主要影响藻类的垂向迁移并存在临界阈值,当风速低于约2.5 m/s的临界风速时,藻华面积随风速增加而增加;当风速高于临界风速时,藻华面积随风速增加而降低。水力调度对距离较近的贡湖湾区域具有显著影响,主要通过水动力扰动来影响...     

鄂尔多斯盆地东南缘上三叠统长8段砂岩储层成岩作用与孔隙演化

鄂尔多斯盆地东南缘上三叠统延长组长8是该区油藏的主力储集层,主要为一套湖泊-三角洲相砂岩,储集岩主要为长石砂岩及长石岩屑砂岩。以岩心观察为基础,结合薄片鉴定、扫描电镜、压汞测试、X-衍射、包裹体测温、Ro测定等方法认为,研究区延长组砂岩经历了压实、胶结、溶解、交代等成岩作用,成岩阶段已达中成岩阶段A期。成岩作用成为控制该区物性的一个关键因素,早期的机械压实和胶结作用使原生孔隙大量丧失,有机质分解形成的酸性流体使储集层中长石等易溶组分的溶蚀对储层物性起到重要的改善作用,成岩阶段后期以（含铁）碳酸盐胶结物为主的胶结又使砂岩致密化。成岩作用中的孔隙演化特征对鄂尔多斯盆地上三叠统延长组低渗透储集层的开发具有积极的意义。