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Scandia doped tungsten matrix for impregnated cathode

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Rare Metals 2008年第1期27卷 9-12页

作者： WANG Jinshu WANG yanchun liu Wei LI Hongyi ZHOU Meiling School of Materials Science and Engineering Beifing University of Technology Beijing 100022 China

As a matrix for Sc-type impregnated cathode,scandia doped tungsten with a uniform distribution of Sc2O3 was obtained by powder metallurgy combined with the liquid-solid doping *** microstructure and composition of the powder and the anti-ion bombardment behavior of scandium in the matrix were studied by means of SEM,EDS,XRD,and in-situ AES *** powder covered with scandium oxide,an ideal scandium oxide-doped tungsten powder for the preparation of Sc-type impregnated cathode,was obtained using the liquid-solid doping *** with the matrix prepared with the mechanically mixed powder of tungsten and scandium oxide,Sc2O3-W matrix prepared with this kind of powder had smaller grain size and uniform distribution of *** on the surface of Sc2O3 doped tungsten matrix had good high temperature stability and good anti-ion bombardment capability.

关键词： scandia tungsten impregnated cathode doping

Rank-Defect Adjustment Model for Survey-Line Systematic Errors in Marine Survey Net

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Geo-Spatial Information Science 2002年第4期5卷 14-20页

作者： liu yanchun LI Mingsan HUANG Motao Department of Hydrography and Mapping Dalian Naval Academy 667 Jiefang Road Dalian 116018 China

In this paper,the structure of systematic and random errors in marine survey net are discussed in detail and the adjustment method for observations of marine survey net is studied,in which the rank_defect characteristic is discovered first up to *** the basis of the survey_line systematic error model,the formulae of the rank_defect adjustment model are deduced according to modern adjustment *** example of calculations with really observed data is carried out to demonstrate the efficiency of this adjustment ***,it is proved that the semi_systematic error correction method used at present in marine gravimetry in China is a special case of the adjustment model presented in this paper.

关键词： marine survey net survey_line error structure rank_defect adjustment model

Preparation and catalytic performance of La_(0.8)Sr_(0.2)CoO_(3) supported on the mullite fiber ceramic

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Frontiers of Chemical Science and Engineering 2007年第4期1卷 372-376页

作者： ZENG Lingke liu yanchun DUAN Bilin liu Ping’an WANG Hui SHUI Anze College of Materials Science and Engineering South China University of TechnologyGuangzhou 510640China A.O.Smith(China)Water Heater Co.Ltd. Nanjing 210038China

The perovskite-type La_(0.8)Sr_(0.2)CoO_(3) supported on the mullite fiber porous ceramics was prepared by means of the impregnating method,and was then characterized by scanning electron microscopy(SEM)and X-ray diffraction(XRD);thus we can come to the conclusion that the perovskite-type composite oxidant can disperse on the surface of mullite fiber *** catalytic activity of the La_(0.8)Sr_(0.2)CoO_(3) for NO and CO was *** effect of the doped 0.1 wt-%PdCl_(2) on the catalytic activity of the perovskite-type La_(0.8)Sr_(0.2)CoO_(3) was also *** results show that the conversion rates of NO and CO respectively reaches 74.5% and 99% at 601℃ without doped Pd,and both reach 100%at 350℃ with a little doped Pd.

关键词： Perovskites-type La_(0.8)Sr_(0.2)CoO_(3) Mullite fiber porous ceramics support palladium catalytic activity

Beyond Reading Comprehension--Cultivating Critical Readers through Critical Press News Reading

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Sino-US English Teaching 2004年第2期1卷 8-18页

作者： Lianzhong Dong yanchun liu Langfang Teachers＇ College Shijiazhuang Railroad Institute

English newspapers, which have already been widely used as supplementary readings in an input-poor Chinese EFL context, are chosen and modified as needed for the proficiency levels of the class and used with suitable activities and exercises that engage students in an active and purposeful construction of the meaning of the text in extensive reading instruction. However, critical reading of the press news, which requires readers moving beyond comprehension, is rarely involved. This article, using Fairclough＇s critical discourse analysis （henceforth, CDA） as the theoretical framework, and Halliday＇s systemic functional grammar （henceforth, SFG） as the analytical tool in the analysis of the news texts, makes a sample analysis of the critical news reading from China Daily on China＇s response to the US-led campaign against terrorism after the September 11 events, 2001. The analysis made is undertaken in three stages：（1） the Transitivity analysis of the headlines, （2） the textual meaning of the clauses in terms of Themes, and （3） the explanations made to give grounding for the preceding analysis. The paper concludes with the hypothesis that integrating critical news reading into extensive reading instruction will not only improve students＇ reading skills, but also increase their adequate comprehension to the reading materials, as well as cultivate their critical reading competence.

关键词： news reading China Daily critical discourse analysis systemic functional grammar

Method for Underwater Target Tracking Based on an Interacting Multiple Model

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Geo-Spatial Information Science 2008年第3期11卷 186-190页

作者： XU Weiming liu yanchun YIN Xiaodong Department of Electronic Engineering Tsinghua University Qinghuayuan Beijing 10084 China Department of Hydrography ＆ Cartography Engineering Dalian Naval Academy 667 Jiefang Road Dalian 116018 China.

According to the requirements of real-time performance and reliability in underwater maneuvering target tracking as well as clarifying motion features of the underwater target, an interacting multiple model algorithm based on fuzzy logic inference （FIMM） is proposed. Maneuvering patterns of the target are represented by model sets, including the constant velocity model （CA）, the Singer mode~, and the nearly constant speed horizontal-turn model （HT） in FIMM technology. The simulation results show that compared to conventional IMM, the reliability and real-time performance of underwater target tracking can be improved by FIMM algorithm.

关键词： underwater target tracking interacting multiple model fuzzy logic inference

Influence of Tide Models on the Use of Altimetry Data to Research Sea Level Anomaly

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Geo-Spatial Information Science 2007年第2期10卷 100-104页

作者： XU Jun BAO Jingyang liu yanchun YU Caixia Department of Hydrography and Cartography Dalian Naval Academy 667 Jiefang Road Dalian 116018 China

A tide model （named DN1.0）, which contains 12 principal constituents over China seas and the Northwest Pacific is estimated by along-track harmonic analysis with TOPEX/Poseidon altimetry data taken from 1993 to 2002. CSR3.0, FES95.2 and DNI.0 are used respectively to detide the data for the time series of sea level anomaly （SLA） in the Yellow Sea, East China Sea, South China Sea and Northwest Pacific. The SLA curves and the power spectral density show that the major components that exist in SLA in China seas arise from the error of the tide models.

关键词： satellite altimetry sea level anomaly tide model tidal aliasing

Algorithm for Harmonic Tidal Analysis along T/P Tracks： Taking Differences of Observed Sea Surface Heights at Adjacent Points as Observations

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Geo-Spatial Information Science 2008年第1期11卷 17-20页

作者： XU Jun BAO Jingyang liu yanchun YU Caixia Department of Hydrography and Cartography Dalian Naval Academy 667 Jiefang Road Dalian 116018 China 不详

An algorithm （differential mode） is presented for the improvement of harmonic tidal analysis along T/P tracks, in which the differences between the observed sea surface heights at adjacent points are taken as observations. Also, the observation equations are constrained with the results of the crossover analysis; the parameter estimations are performed at 0.1° latitude intervals by the least squares. Cycle 10 to 330 T/P altimeter data covering the China Sea and the Northwest Pacific Ocean （2°-50° N,105°-150° E） are adopted for a refined along-track harmonic tidal analysis, and harmonic constants of 12 constituents in 8 474 points are obtained, which indicates that the algorithm can efficiently remove non-tidal effects in the altimeter observations, and improve the precision of tide parameters. Moreover, parameters along altimetry tracks represent a smoother distribution than those obtained by traditional algorithms. The root mean squares of the fitting errors between the tidal height model and the observations reduce from 11 cm to 1.3 cm.

关键词： satellite altimetry T/P harmonic tidal analysis differential mode

Drought shifts soil nematode trophic groups and mediates the heterotrophic respiration

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Journal of Plant Ecology 2024年第2期17卷 100-109页

作者： Cancan Zhao Yuanhu Shao Huijie Lu Aimée T.Classen Zuyan Wang Ying Li yanchun liu Zhongling Yang Guoyong Li Shenglei Fu International Joint Research Laboratory for Global Change Ecology School of Life SciencesHenan UniversityKaifeng 475004China Henan Dabieshan National Field Observation and Research Station of Forest Ecosystem Zhengzhou 450046China Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions Ministry of EducationCollege of Environment and PlanningHenan UniversityKaifeng 475004China Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security Kaifeng 475004China Department of Ecology and Evolutionary Biology University of MichiganAnn ArborMI 48109USA South China Botanical Garden Chinese Academy of SciencesGuangzhou 510650China Department of Natural Resource of Henan Province Institute of Natural Resources Survey and PlanningZhengzhou 450000China

As the most diverse metazoan taxa,soil nematodes serve a diversity of functions in soil food webs and thus can regulate microbial community composition and affect organic matter decomposition and nutrient turnover *** nematodes depend on water flms to access food resources,drought can negatively affect nematode-microbial food webs,yet the impacts of drought on nematode diversity and abundance and how these changes may infuence food web members and their functions are hardly ***,we coupled research along a drought gradient in arid and semiarid grasslands with a detailed intact plant-soil microcosm experiment to explore the patterns and mechanisms of how drought impacts nematode abundance and carbon footprint,microbial phospholipid fatty acid(PLFA)and heterotrophic soil ***,in the feld and the microcosm experiments,we found that nematode abundance,carbon footprint and diversity,microbial PLFA and heterotrophic respiration were reduced under drier *** addition,drought altered nematode and microbial community composition,through reducing the nematode channel ratio and increasing the relative fungivorous nematode abundance and the fungal to bacterial *** soil decomposition channel shifted from a bacterial to a fungal pathway in response to drought,indicating decelerated heterotrophic respiration under *** results highlight the important contribution of soil nematodes and their associated microbial food web to soil carbon *** fndings underscore the need to incorporate key soil fauna into terrestrial ecosystem model evaluation.

关键词： soil biota fungal energy channel bacterial energy channel carbon footprint arid grassland

Magnetic Detection Method for Seabed Cable in Marine Engineering Surveying

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Geo-Spatial Information Science 2007年第3期10卷 186-190页

作者： YU Bo liu yanchun ZHAI Guojun BIAN Gang XIAO Fumin Department of Hydrography and Mapping Dalian Naval Academy 667 Jiefang Road Dalian 116018 China. 不详

The detection and identification of the seabed cable is becoming an important task in the marine engineering. The features of the magnetic anomaly can be used to detect the existence of the seabed cable. The magnetic field model is presented, and the consistency of the magnetic anomaly distribution between the simulation of the model and the observed data is verified. The comparison shows that the seabed cable can be effectively detected and identified with reasonable method.

关键词： seabed cable magnetic filed modeol detection and identification