Current Location:home > Browse

1. chinaXiv:201711.01902 [pdf]

Taxonomic revision of lizards from the Paleocene deposits of the Qianshan Basin, Anhui, China

DONG Li-Ping; Susan E. EVANS; WANG Yuan
Subjects: Biology >> Zoology

Although the Late Cretaceous lizard fauna of China and Mongolia is relatively well-known, information on Paleocene lizards from the same region is currently limited. Several species of lizards have been reported from the Paleocene Wanghudun and Doumu formations of Qianshan Basin on the basis of fragmentary specimens, namely Agama sinensis Hou, 1974, Anhuisaurus huainanensis Hou, 1974, Anqingosaurus brevicephalus Hou, 1976, Changjiangosaurus huananensis Hou, 1976, Qianshanosaurus huangpuensis Hou, 1974, and Tinosaurus doumuensis Hou, 1974. In this paper, we review all the reported material of these taxa with the aid of new technology, including CT scanning, and according to current views of squamate relationships and classification. Revised descriptions and classifications are given for each taxon, leading to changes in our understanding of faunal composition. This, in turn, reveals greater morphological and ecological diversity among the Paleocene lizards of the Qianshan Basin, including the occurrence of a varaniform (IVPP V 22767), and the reinterpretation of Anqingosaurus as a possible burrower. Further work on the Paleocene Qianshan lizards is ongoing and the discovery of new specimens may help to solve the puzzles these strange lizards have posed.

submitted time 2017-11-07 From cooperative journals:《古脊椎动物学报》 Hits1730Downloads753 Comment 0

2. chinaXiv:201701.00030 [pdf]

Characterization of Mixed Target Scattering Using Random Similarity

Dong, Li; Yunhua, Zhang; Yueying, Tang
Subjects: Geosciences >> Space Physics

A random similarity parameter is proposed which can measure not only the scattering similarity of any two scatterers but also the scattering randomness. The parameter covers both the similarity parameters developed by Yang et al. and Chen et al., and provides a fast and competent alternative to the scattering entropy H parameter. The excellence of the parameter on target discrimination is demonstrated by simply applying it to the terrain classification.

submitted time 2017-01-04 Hits1921Downloads910 Comment 0

3. chinaXiv:201701.00029 [pdf]

Unified Phenomenological Decomposition of Radar Targets

Dong, Li; Yunhua, Zhang
Subjects: Geosciences >> Space Physics

Huynen phenomenological decomposition as the first for-malized target decomposition has not been widely accepted. Huynen’s preference for scattering symmetry and regularity restricts not only the application of this decomposition but also its unification with other target dichotomies such as the Barnes-Holm decomposition and Yang decomposition. The non-uniqueness issue then arises because we may have dif-ferent dichotomies of radar targets, but we have no idea on how to select them. Recently, a unified Huynen dichotomy was developed by Li and Zhang to extend Huynen decom-position for a full preference for symmetry and regularity, non-symmetry, irregularity, as well as their couplings. The dichotomy covers all the existing dichotomies and provides an excellent discrimination of radar targets. This paper gives a concise review of the Huynen-type target dichotomies to investigate the existing concerns influencing the application of such decompositions and the corresponding coping me-thods. We hope this review will help to promote the wide acceptation of Huynen-type target dichotomies in the future.

submitted time 2017-01-04 Hits1554Downloads837 Comment 0

4. chinaXiv:201701.00020 [pdf]

Scattering preference pyramid classification of PolSAR data based on canonical huynen dichotomy

Dong, Li; Yunhua, Zhang
Subjects: Geosciences >> Space Physics

Huynen decomposition prefers the world of basic symmetry and regularity (SR) in which we live. However, it is just this preference prevents Huynen decomposition from analyzing the non-symmetric (NS) and irregular (IR) targets. The canonical Huynen dichotomy is proposed to provide two competent supplements to Huynen decomposition by developing two other target dichotomies with the scattering preferences for IR and NS. In virtue of an adaptive combination and permutation of the scattering preferences of the canonical dichotomy, a scattering preference pyramid description of the mixed scattering is developed in this paper. The pyramid is composed of three layers to reflect three different degrees of scattering randomness. Each layer is further composed of several blocks to totally indicate ten different scattering mechanisms. The excellent performance of this scheme is demonstrated by comparing it with the widely-used entropy/alpha classification, and a better discrimination of radar targets is obtained. ?VDE VERLAG GMBH ?Berlin ?Offenbach.

submitted time 2017-01-04 Hits1602Downloads741 Comment 0

5. chinaXiv:201609.00999 [pdf]

Super Strong Magnetic Fields of Neutron Stars in Be X-Ray Binaries Estimated with New Torque and Magnetosphere Models

Chang-Sheng Shi; Shuang-Nan Zhang; Xiang-Dong Li
Subjects: Physics >> Nuclear Physics

We re-estimate the surface magnetic fields of neutron stars (NSs) in Be X-ray binaries (BeXBs) with different models of torque, improved beyond Klus et al. (2014). In particular, a new torque model (Dai \& Li 2006) is applied to three models of magnetosphere radius. Unlike the previous models, the new torque model does not lead to divergent results for any fastness parameter. The inferred surface magnetic fields of these NSs for the two compressed magnetosphere models are much higher than that for the uncompressed magnetosphere model. The new torque model using the compressed-magnetosphere radius (Shi, Zhang \& Li 2014) leads to unique solutions near spin equilibrium in all cases, unlike other models that usually give two branches of solutions. Although our conclusions are still affected by the simplistic assumptions about the magnetosphere radius calculations, we show several groups of possible surface magnetic field values with our new models when the interaction between the magnetosphere and the infalling accretion plasma is considered. The estimated surface magnetic fields for NSs BeXBs in the Large Magellanic Cloud, the Small Magellanic Cloud and the Milk Way are between the quantum critical field and the maximum "virial" value by the spin equilibrium condition.

submitted time 2016-09-14 Hits1579Downloads933 Comment 0

6. chinaXiv:201609.00018 [pdf]

Track segment finding with CGEM-IT and matching to tracks in ODC

Xin-Hua Sun; Liang-Liang Wang; Ling-Hui Wu; Xu-Dong J; Qing-Lei Xiu; Liao-Yuan Dong; Ming-Yi Dong; Wei-Dong Li; Wei-Guo Li; Huai-Min Liu; Qun Ou-Yang; Ye Yuan; Yao Zhang
Subjects: Physics >> Nuclear Physics

The relative differences in coordinates of Cylindrical-Gas-Electron-Multiplier-Detector-based Inner Tracker (CGEM-IT) clusters are studied to search for track segments in CGEM-IT. With the full simulation of single muon track samples, clear patterns are found and parameterized for the correct cluster combinations. The cluster combinations satisfying the patterns are selected as track segment candidates in CGEM-IT with an efficiency higher than 99%. The parameters of the track segments are obtained by a helix fitting. Some chi-squared quantities, evaluating the differences in track parameters between the track segments in CGEM-IT and the tracks found in Outer-Drift-Chamber (ODC), are calculated and used to match them. Proper chi-squared requirements are determined as a function of transverse momentum and the matching efficiency is found reasonable.

submitted time 2016-09-02 Hits1137Downloads610 Comment 0

  [1 Pages/ 6 Totals]