In order to study biostratigraphy and chemical stratigraphy during the Lower Kellwasser event, high resolution conodonts research and chemostratigraphic framework were carried out. The data reveals that the inorganic and organic carbon isotope have a significant positive excursion at the bottom of the Laye section. It is considered that the sample LY-8 is consistent with the Lower Kellwasser boundary. The main reason for the change of carbon isotope in this area is the increase of organic carbon burial, which is caused by the increase of marine primary productivity and anoxia environment possibly.

Graphene-based field-effect transistors (FETs) were fabricated by electron beam lithography and lift-off process and the photoresponse in the transistor was investigated. Significant photocurrents can be detected when the channel graphene near the metal contact is illuminated by a laser spot (λ = 633 nm). Both the magnitude and direction of the photocurrent can be effectively modulated by the back-gate voltage. In addition, the photocurrent will saturate by increasing the gate voltage. A maximum responsivity of 46.5 μA/W is achieved, which can be contributed to develop the novel graphene-based photodetectors.

Given that watershed transform based image segmentation methods usually produce obvious over-segmentation, and the high resolution imagery of urban areas shows some peculiar characteristics, the authors propose a hierarchical region merging method to optimize the segmentation results initially produced by watershed transformation. A multi-channel watershed transformation was adopted to generate an initial segmentation result. Through quantitative analysis of internal spectral variability of different ground objects in urban areas, the image was stratified to several layers. Region merging was separately conducted in each layer. A final segmentation result was obtained by aggregating segmentation results from these layers. The proposed method was evaluated by comparing with the existing watershed segmentation method in terms of visual inspection, quantitative measures and applications in urban land cover classification, using a QuickBird image of Beijing area. The experimental results indicate that the proposed method outperforms the existing method and it is suitable for segmentation of high resolution imagery over urban areas.

The work on the research of pinning effect in the anomalous Hall effect of high-Tc superconductors is reported. Based on the extended power lawequation and consideringthe pinning effect, two scaling relations are deduced which agree well with the experimental data of different superconductors. Meanwhile, based on the results of TDGL (time dependent Ginzburg-Landau) theory and considering pinning effect, two Hall conductivity equations for superconductors with and without double sign reversal were reported.

A hierarchical segmentation method is proposed for multispectral imagery by combining extended watershed transform and dynamics of contours. First, the gradient magnitude of an image is computed, and then local irrelevant minima are eliminated. After computing dynamics of contours, hierarchical (multi-level) segmentation results are produced by thresholding. The proposed method is evaluated with a high spatial resolution image of the urban area, and compared with the existing image segmentation method. The results show that the method can get hierarchical segmentation results, and segmente most of image objects. The segmentation results give the hierarchical representation of land cover types, which is helpful for further object based analysis.

Regressive independence means that conditional expectation E(Y|X) of two random variables X and Y does not depend on X. The relation between regressive independence and random independence is discussed, and several necessary and sufficient conditions are presented.

The title compounds 2-7 have been synthesized.This paper provides asimple and convenient separation method of diasteromers from 5-benzdyl-2, 3-dihydro-1H-Pyrrolizine-1-carboxylic acid and amino acid esters.

The parasite of Rhododendron delavayi Franch, collected from Yunnan Province, was extracted by organic solvents with different polarity. After chromatography and purification six crystallines were isolated from this plant for the first time. On the bases of physical and chemical properties and spectral analyses five of them were identified as nonacosane(A), succinic acid(C), quercetin(D), quercetin-3-O-α-arabinofuranoside(E), and quercetin-3-O-α-rhamnopyranoside(F) separately, crystalline B, identified by GC/MS, is a mixture composed of campesterol(Ⅰ), brassicasterol(Ⅱ), stigemasterol(Ⅲ) and γ -sitosterol(Ⅳ).