检索结果-南通市图书馆

Natural vegetation restoration of Liaodong oak(Quercus liaotungensis Koidz.) forests rapidly increased the content and ratio of inert carbon in soil macroaggregates

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2019年第6期11卷 928-938页

作者： sun lipeng HE Lirong WANG Guoliang JING Hang LIU Guobin Institute of Soil and Water Conservation Northwest A&F UniversityYangling 712100China Shaanxi Provincial Land Engineering Construction Group Co. Ltd.Xi'an 710075China

The lack of clarity of how natural vegetation restoration influences soil organic carbon(SOC) content and SOC components in soil aggregate fractions limits the understanding of SOC sequestration and turnover in forest *** aim of this study was to explore how natural vegetation restoration affects the SOC content and ratio of SOC components in soil macroaggregates(>250 μm), microaggregates(53–250 μm), and silt and clay(2.0 mm diameter) on SOC components were studied *** showed that the contents of high activated carbon(HAC), activated carbon(AC) and inert carbon(IC) in the macroaggregates, microaggregates and silt and clay fractions increased with restoration ***, IC content in the microaggregates in topsoil(0–20 cm) rapidly increased;peaking in the 90-year-old restored forest, and was 5.74 times higher than AC *** deep soil(20–80 cm), IC content was 3.58 times that of AC *** of 0.5–1.0 mm diameter roots and leaf litter affected the content of aggregate fractions in topsoil, while the biomass of >2.0 mm diameter roots affected the content of aggregate fractions in deep *** the soil profiles, macroaggregates had the highest capacity for HAC *** effects of restoration ages on soil aggregate fractions and SOC content were less in deep soil than in *** conclusion, natural vegetation restoration of Liaodong oak forests improved the contents of SOC, especially IC within topsoil and deep *** influence of IC on aggregate stability was greater than the other SOC components, and the aggregate stability was significantly affected by the biomasses of litter, 0.5–1.0 mm diameter roots in topsoil and >2.0 mm diameter roots in deep *** vegetation restorati

关键词： activated carbon leaf litter soil organic carbon soil aggregates silt and clay Shaanxi

Research on User Terminals’ Acquisition Sensitivity Based On P2P Aiding

在线全文

学校读者我要写书评

暂无评论

Research on User Terminals’ Acquisition Sensitivity Based O...

Seismic energy dispersion compensation by multi-scale morphology

第五届中国卫星导航学术年会

作者： Dai Weiheng Tian Shiwei sun lipeng Chang Jiang College of Communication Engineering of PLA University of science and technology Taiyuan Satellite Launch Center

ISBN: (纸本)9783642547362

With development of short range communication technology,P2P（Peer to Peer） networks are pervasive, and the nav-com user terminals become popular. The application of P2P networks provide the new method to improve positioning performances of user terminals. Compared to conventional A-GNSS augmentation,P2P aiding is completed by user terminals each other, which don’t depend on preinstalled communication infrastructures （ e.g., mobile communication base stations ） . In P2P networks ,aiding sources are closer to aided users than conventional base stations aiding. The advantage can provide more accurate and reliable augmentation information, so the user terminals can get better augmentation performances. Now there are some groups research P2P aiding,but their topic is the mean acquisition times. But the acquisition sensitivity is very important metric for both military users and civil *** paper researches performance of acquisition sensitivity in P2P networks. The aiding peer can receive both GNSS signals and the communication signals of aided peer,. According to the real-time measurements of carrier phase and frequency offset , the aided peer can get real-time local frequency offset values. Based on these values, the peer can extend coherent integration time and improve the acquisition sensitivity. Simulation show that the aided user can complete coherent integration of several seconds, and the non-aided user only do for hundreds of milliseconds. The aided terminal can reliably work in low signal-noise ration, 1 even in 10dB Hz condition. The requirement of communication rate is less than 1kps.

关键词： P2P aiding Acquisition sensitivity Coherent integration time

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Petroleum Science 2014年第3期11卷 376-384页

作者： Yu Junqing Wang Runqiu Liu Taoran Zhang Zhenglong Wu Jian Jiang Yongyong sun lipeng Xia Pei College of Geophysics and Information Engineering China University of Petroleum (Beijing) BGP Research & Development Center

Seismic energy decays while propagating subsurface, which may reduce the resolution of seismic data. This paper studies the method of seismic energy dispersion compensation which provides the basic principles for multi-scale morphology and the spectrum simulation method. These methods are applied in seismic energy compensation. First of all, the seismic data is decomposed into multiple scales and the effective frequency bandwidth is selectively broadened for some scales by using a spectrum simulation method. In this process, according to the amplitude spectrum of each scale, the best simulation range is selected to simulate the middle and low frequency components to ensure the authenticity of the simulation curve which is calculated by the median method, and the high frequency component is broadened. Finally, these scales are reconstructed with reasonable coefficients, and the compensated seismic data can be obtained. Examples are shown to illustrate the feasibility of the energy compensation method.

关键词： Seismic wave multi-scale morphology dispersion compensation high resolution median method spectrum simulation

Efficiently Writing Bragg Grating in High-Birefringence Elliptical Microfiber for Label-Free Immunosensing with Temperature Compensation

在线全文

学校读者我要写书评

暂无评论

Advanced Fiber Materials 2021年第5期3卷 321-330页

作者： Peng Xiao Zhiyuan Xu Deming Hu Lili Liang lipeng sun Jie Li Yang Ran Bai‑Ou Guan Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics TechnologyJinan UniversityGuangzhou 510632China Ji Hua Laboratory Foshan 528300China Institute of Information Technology Handan UniversityHandan 056005China

Immunosensor is a powerful tool in healthcare and clinic,food and drug industry,and environmental ***-free fiber-optic immunosensors have shown a myriad of advantages,such as high sensitivity,anti-electromagnetic interference,and afield measurement via the fiber ***,the fiber-optic based sensor may bear the temperature cross-talk,especially under the warming condition for bio-activating the immune *** this study,we proposed a highly birefringent microfiber Bragg grating for immunosensing with the *** birefringent microfiber was drawn from the elliptical cladding multimode fiber that was ablated by the CO2 *** considerably large energy overlap region offered by the original multimode fiber favored the efficient inscription of FBG with high *** dual reso-nances derived by the orthogonal polarization states presented similar temperature responsivities but significantly different ambient refractive index sensitivities,allowing the temperature-compensational RI *** human immunoglobulin G(IgG)molecules were anchored on the surface of the microfiber grating probe by the covalent functionalization technique to enable the specific detection of the anti-IgG *** proposed method promises a high-efficiency and low-cost design for the microfiber Bragg grating-based biosensor without being subjected to the temperature cross-sensitivity.

关键词： Fiber-optic biosensors Microfiber Fiber Bragg grating Birefringence Temperature compensation Immunosensing

Risks and Path Choices of the Tapering of Federal Reserve QE and Its Impact on China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Contemporary International Relations 2014年第3期24卷 113-129,5页

作者： sun lipeng sun Chenghao the Institute of American Studies CICIR

In December 2013,the Federal Open Market Committee （FOMC） formally announced that it would wind down the size of its large-scale asset purchase *** formally set in motion the exit of quantitative easing （QE）.However,at present,the American unemployment rate is still relatively high,the real estate market is gloomy,inflation is too low,the balance sheet is facing an unexpected increase in risks,and policies are confionted with cost *** such circumstances,the Fed is faced with multiple challenges in the tapering of *** policy has made great contributions to helping the United States to shake off financial crisis,and the safe and smooth exit of the policy is of the utmost importance to the recovery of the *** and the reshaping of *** addition,the Fed＇s monetary policy reversal will engender spillover risks and challenges for China＇s economy.

关键词：中国经济量化风险房地产市场松美国联邦路径金融危机

*** Ties:Steady Progress in Cooperation

在线全文

学校读者我要写书评

暂无评论

China Today 2016年第7期65卷 46-49页

作者： sun lipeng the Institute of American Studies under the China Institute of Contemporary International Relations

THE *** is one of the most significant bilateral ties in the *** ballast in this relationshipeconomic and trade cooperation-is at the same time a key engine driving global economic *** the financial crisis in 2008,the... 详细信息

关键词： over

A CCD based machine vision system for real-time text detection

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Optoelectronics 2020年第4期13卷 418-424页

作者： Shihua ZHAO lipeng sun Gang LI Yun LIU Binbing LIU State Grid Hunan Electric Power Corporation Limited Research Institute Changsha 410007China State Grid Hunan Electric Power Corporation Limited Changsha 410007China School of Optical and Electronics Information Huazhong University of Science and TechnologyWuhan 430074China

Text detection and recognition is a hot topic in computer vision,which is considered to be the further development of the traditional optical character recognition(OCR)*** the rapid development of machine vision system and the wide application of deep learning algorithms,text recognition has achieved excellent *** contrast,detecting text block from complex natural scenes is still a challenging *** present,many advanced natural scene text detection algorithms have been proposed,but most of them run slow due to the complexity of the detection pipeline and can not be applied to industrial *** this paper,we proposed a CCD based machine vision system for realtime text detection in invoice *** this system,we applied optimizations from several aspects including the optical system,the hardware architecture,and the deep learning algorithm to improve the speed performance of the machine vision *** experimental data confirms that the optimization methods can significantly improve the running speed of the machine vision system and make it meeting the real-time text detection requirements in industrial scenarios.

关键词： machine vision text detection optical character recognition(OCR) deep learning

Analysis of Non-Sinusoidal Steady Electric Field of ±500 kV Converter Transformer

在线全文

学校读者我要写书评

暂无评论

Energy and Power Engineering 2017年第4期9卷 53-62页

作者： Gang Liu Cheng Chi Yanjiao Jin Yongqiang Ma lipeng sun Lin Li Youliang sun Hebei Provincial Key Laboratory of Power Transmission Equipment Security Defense North China Electric Power Universi-ty Baoding China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing China Shandong Power Equipment Co. Ltd. Jinan China

The line side winding is under the fundamental frequency AC voltage, while the valve side winding contains not only fundamental AC voltage component, but also the DC voltage component, fundamental AC voltage component, and higher harmonic voltage components when the converter transformer is at its normal operating condition, and the electric field of converter transformer is a non-sinusoidal steady one. To analyze the non-sinusoidal steady electric field containing the DC component, fundamental AC and higher harmonic components, the voltage spectrum of the valve winding in a ±500 kV converter transformer is firstly analyzed, and the non-sinusoidal periodic steady electric field is obtained by the fast discrete Fourier transform. Different resistivity of the oil and oil-immersed paper is adopted to simulate the aging of oil paper insulation at operation, and get the non-sinusoidal steady electric field.

关键词： Converter Transformer AC-DC Hybrid Non-Sinusoidal Periodic Electric Field

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

矩形钢管混凝土壁板的屈曲后强度

建筑结构学报 2022年第10期43卷 259-273页

作者：孙立鹏刘永健长安大学公路学院陕西西安710064 公路大型结构安全教育部工程研究中心陕西西安710064

为研究矩形钢管混凝土壁板的屈曲后强度,根据平板的弹塑性屈曲理论并考虑残余应力的影响,确定了板件发生塑性屈曲、弹塑性屈曲和弹性屈曲的正则化界限宽厚比。采用试验验证的有限元模型进行了宽厚比为20~150、钢材屈服强度为275~960 MP... 详细信息

为研究矩形钢管混凝土壁板的屈曲后强度,根据平板的弹塑性屈曲理论并考虑残余应力的影响,确定了板件发生塑性屈曲、弹塑性屈曲和弹性屈曲的正则化界限宽厚比。采用试验验证的有限元模型进行了宽厚比为20~150、钢材屈服强度为275~960 MPa的矩形钢管混凝土壁板局部屈曲分析,以界限宽厚比为控制点,根据有限元结果拟合出了矩形钢管混凝土壁板的有效宽度计算式。研究结果表明:弹性屈曲板件的屈曲后强度提高程度显著高于弹塑性屈曲板件;屈曲后强度的提高程度与钢材屈服强度无明显相关性;与无面外约束钢板相比,混凝土的单侧约束作用可使板件的屈曲后强度普遍提高约50%;提出的矩形钢管混凝土壁板的正则化界限宽厚比和有效宽度计算式与试验结果吻合较好,有效宽度试验值比所提公式计算值平均增大7.2%,标准差为0.091。

关键词：钢管混凝土屈曲后强度宽厚比有效宽度单侧约束板