Estimating canopy water content using hyperspectral remote sensing data

Hyperspectral remote sensing has demonstrated great potential for accurate retrieval of canopy water content (CWC). This CWC is defined by the product of the leaf equivalent water thickness (EWT) and the leaf area index (LAI). In this paper, in particular the spectral information provided by the canopy water absorption feature at 970 nm for estimating and predicting CWC was studied using a modelling approach and in situ spectroradiometric measurements. The relationship of the first derivative at the right slope of the 970 nm water absorption feature with CWC was investigated with the PROSAIL radiative transfer model and tested for field spectroradiometer measurements on two test sites. The first site was a heterogeneous floodplain with natural vegetation like grasses and various shrubs. The second site was an extensively grazed fen meadow.     

光谱增感染料的结构与其光谱吸收

增感染料在摄影、印刷制版等领域中的应用是十分广泛的，增感染料可以使感光材料的感光度提高，可以改善和扩大其感色性和画面层次等。增感染料的增感效率与其光吸收有着直接的关系，而增感染料的光吸收作用又受到其结构的影响。本文分析了增感染料的结构对其光谱吸收的影响。     

土壤吸附汞测量方法在哈尔滨市活断层探测中的应用

应用土壤吸附汞测量技术在哈尔滨市部分地区进行活动断层探测,确定滨州断裂的(哈尔滨段)位置和走向与已有地质资料结果稍有偏离;松北断裂和现有结果基本一致;阿什河断裂(哈尔滨段)为两条近似平行隐伏断裂。     

X-ray Spectromicroscopy of Mineral Intergrowths in the Santa Catharina Meteorite

This work describes the application of microfocus X-ray absorption spectroscopy (XAS) and X-ray photo-emission electron microscopy (XPEEM) to the study of the complex mineralogical intergrowths within the Santa Catharina meteorite. The Santa Catharina meteorite of this study (BM52283 from the meteorite collection of the Natural History Museum, London, UK) primarily comprises a taenite bulk host phase (Fe:Ni ratio = 70.9 ± 0.8%:29.1 ± 0.8%) with a set of oxide-bearing cloudy zone textured regions (Fe:Ni:O ratio = 40.4 ± 0.3%:49.0 ± 0.7%:10.6 ± 0.8% at the core and Fe:Ni:O ratio = 34.4 ± 1.5%:42.7 ± 0.6%:22.9 ± 1.8% towards the rims) and numerous schreibersite (Fe:Ni:P ratio = 38.6 ± 1.6%:38.4 ± 0.9%:23.0 ± 0.5%) inclusions. Between the schreibersite and the taenite are rims up to 50 μm across of Ni-rich kamacite (Fe:Ni ratio = 93.4 ± 0.4%:6.6 ± 0.5%). No chemical zoning or spatial variations in the Fe and Ni speciation was observed within either the schreibersite or the kamacite phases. The oxide-bearing cloudy zone textured regions mostly comprise metallic Fe–Ni alloy, predominantly tetrataenite. Within the oxide phases, the Fe is predominantly, but not entirely, tetrahedrally co-ordinated Fe³⁺ and the Ni is octahedrally co-ordinated Ni²⁺. Structural analysis supports the suggestion that non-stoichiometric Fe₂NiO₄ trevorite is the oxide phase. The trevorite:tetrataenite ratio increases at the edges of the oxide-bearing cloudy zone textured regions indicating increased oxidation at the edges of these zones. The spatial resolution of the XPEEM achieved was between 110 and 150 nm, which precluded the study of either the previously reported ∼ 10 nm precipitates of tetrataenite within the bulk taenite or any antitaenite.     

Research on coda Q distribution in Beijing and its surrounding regions

Based on the single scattering model of seismic coda waves, we have calculated theQ-factor in Beijing and its surrounding regions by means of calculating the power density spectrum in frequency domain with a fixed time window. The digital seismic data of 69 earthquakes from Beijing Telemetered Seismographic Network are used. These earthquakes were recorded from January 1, 1989 to December 31, 1990 at 20 stations. This paper shows the variations of the codaQ-factors in the studied region with different sites, frequency and lapse time, and the temporal change of the codaQ-factors in these two years. The results indicate that codaQ-factor depends strongly on the lapse time and frequency. It is assumed that whenQ _C=Q ₀f^η, for the three time windows of 15–30s, 30–60s and 60–90s, the average values ofQ ₀ are 48, 115 and 217; and the average values ofη are 0. 89, 0.91 and 0.74, respectively. Contribution No. 95A0009, Institute of Geophysics, SSB, China. This work is a contract subject 85-04-01-02 of the State Seismological Bureau, China.     

曲线桥梁摩擦滑移隔振试验及隔振机理研究

针对曲线桥梁在地震中因固定支座处及桥墩底部受力过大而破坏严重的现象,提出考虑支座摩擦滑移隔震的曲线桥梁抗震设计方法,通过大型振动台模型试验,研究曲线桥梁考虑支座摩擦滑移时的隔震机理。试验结果表明:支座摩擦滑移可有效减小地震作用下曲线桥梁的桥墩加速度响应,但同时会增加桥墩与梁体间的相对位移;曲线桥梁进行隔震设计后,桥墩的应变响应明显减小,证明该设计方法可有效避免地震作用下桥墩底部产生较大的损伤;最后,探讨了考虑支座摩擦滑移时曲线桥梁的隔震机理并与震害进行了对比验证。研究成果可为曲线桥梁的减震隔设计提供新的视角。     

综合利用多种地球物理方法预测中层目标含气范围

莺歌海盆地浅层典型已知“亮点型”气藏的地球物理特征已经非常清楚,而且大部分目标都已列入储量计算的范畴,所以勘探潜力不是很大,这就要求我们应该把目光投向中层目标来寻找储量接替.但是若想准确的计算储量,就应该落实目标体的含气范围,但是由于埋深、压力及浅层目标屏蔽的影响,中层目标的地球物理特征我们还不是很清楚,更难较准确的确定含气范围.本文带着这个问题展开研究,第一步通过地震属性分析确定异常体的范围,通过反演确定砂体范围;第二步通过聚类分析确定有利砂体的范围;第三步通过叠后吸收处理判断目标体的含气性;最后,将有利砂体的范围与吸收异常的范围叠合来确定目标体的含气范围.综合应用多种地球物理方法判断目标体的含气性,总结出了一套预测中层目标含气范围的流程及方法,为较准确的落实中层目标含气范围奠定了基础.