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Search Results: 1 - 10 of 78192 matches for " Sipeng Chen "
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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,
Abstract:
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
Abstract:

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

EXPERIMENTAL STUDY ON THE RELATION BETWEEN THE BURST TENDENCY AND WATER CONTENT IN COAL SEAM
煤层冲击倾向性与含水率关系的试验研究

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

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.
Crystallization properties of Sn--doped Ge--Sb--Te phase--change films
Sn掺杂Ge-Sb-Te相变薄膜的晶化特性

GU Sipeng,HOU Lisong,ZHAO Qitao,
顾四朋
,侯立松,赵启涛

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.
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
空间影响域覆盖最大的航标自动选取方法
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,
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.
Microwave induced oxidation process for Argazol Blue BF-BR wastewater treatmentwith modified alumina as catalyst
改性氧化铝微波诱导氧化处理雅格素蓝BF-BR染料废水的研究

HONG Guang,WANG Peng,ZHANG Guoyu,MA Huijun,JIANG Sipeng,
洪光
,王鹏,张国宇,马慧俊,姜思朋

环境科学学报 , 2005,
Abstract: 采用微波诱导氧化工艺(MIOP)技术,以改性氧化铝为催化剂,对雅格素蓝BF-BR染料模拟废水进行氧化处理.优化了处理工艺条件,实验在固液质量比为1:10(50mL雅格素蓝BF-BR水溶液中投加5.0g改性氧化铝)、微波功率为400W的条件下微波辐照处理5min.在此工艺条件下,对水中雅格素蓝BF-BR的脱色率可达到98%,COD去除率为87.4%.改性氧化铝在重复使用9次后仍能保持很高的脱色率.进一步研究表明在微波辐射场中废水中的有机污染物在改性氧化铝表面通过吸附.氧化协同作用而被迅速降解.反应动力学研究表明,该氧化过程符合一级反应动力学规律,反应速率常数k=0995min^-1,反应半衰期t1/2=0.697min.实验结果显示,在本实验中改性氧化铝比颗粒活性炭具有更高的催化活性.
Preliminary study on the emissions and pollution control of PCDDs/Fs from crematories in China
中国火葬场二口恶英类污染物排放及减排技术研究

WANG Wei,XIAO Chenglong,LI Datao,JIANG Sipeng,HU Daoqing,
王玮
,肖成龙,李大涛,姜思朋,胡道庆

环境科学学报 , 2006,
Abstract: 对中国某火葬场9具遗体进行了二(口恶)英类污染物排放测试,测试结果表明,烟气中二(口恶)英类物质总浓度为89~350ng·m-3,毒性当量浓度为1.5~5.4ng·m-3;PCDFs的总浓度高于PCDDs的总浓度;以此估算中国2004年火化遗体过程中二(口恶)英类污染物的年排放量为11.2~46.9 g·a-1.通过实验分别研究了布袋除尘器、布袋除尘器加不同厚度的活性炭纤维毡组合对火化遗体烟气中二(口恶)英类污染物的去除效果.结果表明,布袋除尘器去除火化烟气中二(口恶)英类污染物的效率为57.4%;布袋除尘器分别与厚度为5、15mm的活性炭纤维毡组合去除火化烟气中二(口恶)英类污染物的效率分别为64.0%和89.2%.
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