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Search Results: 1 - 10 of 28407 matches for " SUN Sipeng "
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Perfectly Matched Layer for an Elastic Parabolic Equation Model in Ocean Acoustics Perfectly Matched Layer for an Elastic Parabolic Equation Model in Ocean Acoustics
XU Chuanxiu,ZHANG Haigang,PIAO Shengchun,YANG Shi'e,SUN Sipeng,TANG Jun
- , 2017,
Abstract: The perfectly matched layer(PML) is an effective technique for truncating unbounded domains with minimal spurious reflections. A fluid parabolic equation(PE) model applying PML technique was previously used to analyze the sound propagation problem in a range-dependent waveguide(Lu and Zhu, 2007). However, Lu and Zhu only considered a standard fluid PE to demonstrate the capability of the PML and did not take improved one-way models into consideration. They applied a [1/1] Padé approximant to the parabolic equation. The higher-order PEs are more accurate than standard ones when a very large angle propagation is considered. As for range-dependent problems, the techniques to handle the vertical interface between adjacent regions are mainly energy conserving and single-scattering. In this paper, the PML technique is generalized to the higher order elastic PE, as is to the higher order fluid PE. The correction of energy conserving is used in range-dependent waveguides. Simulation is made in both acoustic cases and seismo-acoustic cases. Range-independent and range-dependent waveguides are both adopted to test the accuracy and efficiency of this method. The numerical results illustrate that a PML is much more effective than an artificial absorbing layer(ABL) both in acoustic and seismo-acoustic sound propagation modeling
The Triangle Inequality and Its Applications in the Relative Metric Space  [PDF]
Zhanjun Su, Sipeng Li, Jian Shen
Open Journal of Discrete Mathematics (OJDM) , 2013, DOI: 10.4236/ojdm.2013.33023

Let C be a plane convex body. For arbitrary points , a,b ∈E ndenote by │ab│ the Euclidean length of the line-segment ab. Let a1b1 be a longest chord of C parallel to the line-segment ab. The relative distance dc(a,b) between the points a and b is the ratio of the Euclidean distance between a and b to the half of the Euclidean distance between a1 and b1. In this note we prove the triangle inequality in E2 with the relative metric dc( .,.), and apply this inequality to show that 6≤l(P)≤8, where l(P) is the perimeter of the convex polygon P measured in the metric dp

Space-Time Cluster Analysis of Tuberculosis Incidence in Beijing, China  [PDF]
Gehendra Mahara, Mina Karki, Kun Yang, Sipeng Chen, Wei Wang, Xiuhua Guo
Journal of Tuberculosis Research (JTR) , 2018, DOI: 10.4236/jtr.2018.64027
Abstract: Tuberculosis is one of the top killer diseases in the globe. The aim of this study was to explore the geographic distribution patterns and clustering characteristics of the disease incidence in terms of both space and time with high relative risk locations for tuberculosis incidence in Beijing area. A retrospective space-time clustering analysis was conducted at the districts level in Beijing area based on reported cases of sputum smear-positive pulmonary tuberculosis (TB) from 2005 to 2014. Global and local Moran’s I, autocorrelation analysis along with Ord (Gi*) statistics was applied to detect spatial patterns and the hotspot of TB incidence. Furthermore, the Kuldorff’s scan statistics were used to analyze space-time clusters. A total of 40,878 TB cases were reported in Beijing from 2005 to 2014. The annual average incidence rate was 22.11 per 100,000 populations (ranged from 16.55 to 25.71). The seasonal incidence occurred from March to July until late autumn. A higher relative risk area for TB incidence was mainly detected in urban and some rural districts of Beijing. The significant most likely space-time clusters and secondary clusters of TB incidence were scattered diversely in Beijing districts in each study year. The risk population was mainly scattered in urban and dense populated districts, including in few rural districts.
Reproduction strategy of Trias verrucosa (Orchidaceae) from China

Liu Zhongjian,Chen Lijun,Lei Sipeng,Rao Wenhui,Li Liqiang,

生态学报 , 2007,
Crystallization properties of Sn--doped Ge--Sb--Te phase--change films

GU Sipeng,HOU Lisong,ZHAO Qitao,

材料研究学报 , 2004,
Abstract: Sn-doped Ge_2Sb_2Te_5 thin films were prepared by RF-sputtering.The effect of Sn- content on their crystallization properties was studied by XRD and DSC.The XRD spectra of the films in the as-deposited and heat-treated states showed that the films changed from amorphous to crystalline states due to heat-treatment and Sn-Te phase appeared.Using DSC data of the amorphous film materials,the activation energies were calculated by measuring the peak crystallization temperatures at different heating rates.It was found that the Ge-Sb-Te-Sn samples have higher activation energy of crystallization than that of the Ge_2Sb_2Te_5 sample.It is concluded from these results that Sn-doping can increase the crystallization rate of the Ge_2Sb_2Te_5 phase-change material,and thereby increase the erasing speed of the material for rewritable optical storage.
A Method for Selecting Aids to Navigation Automatically Based on the Maximal Covering of Their Spatial Influence Domains

李思鹏, 张立华, 贾帅东
LI Sipeng
, ZHANG Lihua, JIA Shuaidong

- , 2017, DOI: 10.13203/j.whugis20150460
Abstract: 针对当前海图制图综合中航标手工选取作业效率低、选取结果受限于作业人员业务水平和工作态度等不足,提出了一种基于空间影响域覆盖最大的航标自动选取方法。通过定义空间影响域,创建空间影响域模型,加权评估航标地理位置重要性,设计空间影响域覆盖最大的分轮次自动选取策略,实现了航标的自动选取。实验结果表明:本文方法实现了航标的自动选取且结果符合《中国航海图编绘规范》要求,能避免手工选取可能存在的明显失误和不同作业人员可能导致的结果不一致性,作业效率明显高于当前普遍使用的手工选取方法
Influence of Ar/N2 Flow Rate on Structure and Property for TaN/NbN Multilayered Coatings
Xuehua ZHANG,Yuanbin KANG,Sipeng LIU,Qiang LI,Ying YANG,Xiangyun DENG,Dejun LI,

材料科学技术学报 , 2007,
Abstract: TaN/NbN multilayered coatings with nanoscale bilayer periods were synthesized at different Ar/N2 flow rates by RF (radio frequency) magnetron sputtering. XRD (X-ray diffraction) and Nano Indenter System were employed to investigate the influence of Ar/N2 flow rate (FAr:FN2) on microstructure and mechanical properties of the coatings. The low-angle XRD pattern indicated a well-defined composition modulation and layer structure of the multilayered coating. All multilayered coatings almost revealed higher hardness than the rule-of-mixtures value of monolithic TaN and NbN coatings. At FAr:FN2=10, the multilayered coating possessed desirable hardness, elastic modulus, internal stress, and fracture resistance, compared with ones synthesized at other Ar/N2 flow rates. The layered structure with strong mixture of TaN (110), (111), (200) and Nb2N (101)textures should be related to the enhanced mechanical properties.
Formal Derivation of the Combinatorics Problems with PAR Method  [PDF]
Lingyu SUN, Yatian SUN
Journal of Software Engineering and Applications (JSEA) , 2009, DOI: 10.4236/jsea.2009.23026
Abstract: Partition-and-Recur (PAR) method is a simple and useful formal method. It can be used to design and testify algo-rithmic programs. In this paper, we propose that PAR method is an effective formal method on solving combinatorics problems. Furthermore, we formally derive combinatorics problems by PAR method, which cannot only simplify the process of algorithmic program's designing, but also improve its automatization, standardization and correctness. We develop algorithms for two typical combinatorics problems, the number of string scheme and the number of error per-mutation scheme. Lastly, we obtain accurate C++ programs which are transformed by automatic transforming system of PAR platform.
Deliberative Democracy: A Probe into Female Interests Demands and Response Mechanism in Shanghai  [PDF]
Lili Sun, Lingling Sun
Open Journal of Political Science (OJPS) , 2017, DOI: 10.4236/ojps.2017.71013
Abstract: Last year, deliberative democracy in mass organization gained great importance in China, which made new demands on the All-China Women’s Federation in representing and integrating the female interests, and also provided it new opportunities to strengthen its function in community governance. Facing the new characteristics, the authors analyze how the Shanghai Women’s Federation develops the response route and mechanism of female interests from the perspective of deliberative body, content and approach.

Mao Xianbiao,Chen Zhanqing,Xu Sipeng,Li Tianzhen,
茅献彪 陈占清 徐思朋

岩石力学与工程学报 , 2001,
Abstract: The relations are determined systematically between the burst tendency and water content, the water content and porosity in coal seam by experiment. It is found that the burst tendency of coal seam depends inversely on the water content, and it is most sensitive in original water content. The saturated water content in coal seam depends on porosity in coal. A reliable quantitative basis is provided for preventing rockburst in coal mine by using water injection method.
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