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Early ERP effects on the scaling of spatial attention in visual search

Progress in Natural Science:Materials International 2008年第4期18卷 381-386页

作者： Ya-Nan Niu a,b, Jing-Han Wei a, Yue-Jia Luo a,c, a Institute of Psychology, Chinese Academy of sciences, beijing 100101,{2. b Graduate school of Chinese Academy of sciences, beijing 100049,{2. c State key laboratory of Cognitive Neuroscience and Learning, beijing normal university, 19 Xin-wai Avenue, beijing 100875,{2. Institute of Psychology Chinese Academy of Sciences Beijing 100101 China Graduate school of Chinese Academy of sciences Beijing 100049 China State key laboratory of Cognitive Neuroscience and Learning Beijing Normal University 19 Xin-wai Avenue Beijing 100875 China

This article describes the examination of the spatial ’scaling’ effect of visual attention with the technique of event-related potential (ERP). Eighteen participants were involved in a visual search task in which the cue-target paradigm was used. The search array was three concentric circles consisting of randomly selected English letters that were equally distributed in each circle. The behavioral and ERP data were recorded, respectively. The behavioral results showed that the response time increased and the response accuracy decreased with the increase of precue size. The ERPs amplitude of P1 and N1 components evoked by search array increased with the reduction of precue size. However, the latencies of these ERP components did not show significant differences between conditions. The hierarchical data of both behavioral assessment and ERPs provided evidence for the spatial ’scaling’ effect of visual attention. The amplitudes of P1 and N1 components may be used as indices to examine the effect of spatial ’scaling’. In different tasks, the display-set size of stimuli and the task complexity may be important factors that affect the attention allocation.

关键词： Visual search Spatial attention ‘Scaling’ effect Event-related potential

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Denitrification in Chongming east tidal flat sediment, Yangtze estuary, china

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Science china Earth sciences 2006年第10期49卷 1090-1097页

作者： WANG Dongqi1,2. CHEN Zhenlou1,3, XU Shiyuan1,2. HU Lingzhen1 & WANG Jun1,2.1. College of Resources & environment, East china {2. university, Shanghai 2.0062. china 2. State key laboratory of Estuarine and Coastal sediment Dynamics and Morphodynamics, East china {2. university, Shanghai 2.0062. china 3. key laboratory of Geographical Information Science of ministry of education,East china {2. university,Shanghai 2.0062. china 1. College of Resources & environment East China Normal University Shanghai 200062 China 2. State key laboratory of Estuarine and Coastal {2. Dynamics and Morphodynamics East China Normal University Shanghai 200062 China 3. key laboratory of Geographical Information Science of {2. of education East China Normal University Shanghai 200062 China

From July 2.03 to July 2.04, samples were collected on Chongming Island east tidal flat every two months. The research showed that the nitrous oxide (N2.) production rate was very low in the water, Chongming east tidal flat (CM) sediment was the N2. source of the water. sediment N2. natural production rate was between -0.08 and 1.74 μmolN·m-2.h-1. N2. natural production rate was higher in the summer. The difference of the N2. natural production rate in the different tidal flats, the correlation between the N2. natural production rate and the denitrification rate, and those with the temperature and DO indicate that middle tidal flat sediment denitrification was the main process of the N2. production, while in the low tidal flat sediment, the production of the N2. came from several processes of the nitrogen cycling. Tidal flat sediment denitrification reaction was stronger in summer and winter but relatively lower in the late autumn and early spring. Seasonal change of the sediment denitrification rate was wide, from 1.12.to 33.34 μmolN·m-2.h-1. Temperature, DO and the coactions of them had the prominent effect on the tidal flat sediment denitrification.

关键词： Yangtze estuary, tidal flat sediment, denitrification, nitrous oxide, effect factor.

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Distribution and origin of biologically available phosphorus in the water of the Meiliang Bay in summer

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Science china Earth sciences 2006年第z1期49卷 146-153页

作者： HUANG Qinghui, WANG Zijian, WANG Donghong, MA Mei & WANG Chunxia State key laboratory of {2.al Aquatic Chemistry, Research Center for Eco-{2.al sciences, Chinese Academy of sciences, beijing 100085, china key laboratory of Yangtze Aquatic {2. (ministry of {12.), College of {2.al Science and Engineering, Tongji university, Shanghai 2.0092. china Chinese Acad Sci Ecoenvironm Sci Res Ctr State Key Lab Environm Aquat Chem Beijing 100085 Peoples R China Tongji Univ Coll Environm Sci & Engn Minist Educ Key Lab Yangtze Aquat Environm Shanghai 200092 Peoples R China

The investigation and continuous monitoring with an innovative iron oxide embedded cellulose acetate membrane (FeO/CAM) on the concentrations of biologically available phosphorus (BAP) were conducted in the Meiliang Bay of the Taihu Lake during summer in 2.04. The results showed that the concentrations of dissolved (FeO-DP), particulate (FeO-PP) and total bioavailable phosphorus (FeO-P) had similar horizontal distribution. The BAP concentrations were the highest in those estuaries in the northern bay. With the decrease of the distance to the estuary or long shore,there was little difference between BAP concentrations in an open lake area. During the observation period, algal blooms occurred in most waters of the northern bay, which was reflected from the high concentrations of chlorophyll a (Chl-a). While they were not highest in the estuarine waters of those major rivers, this is the case for the BAP concentrations. The concentrations of Chl-a had a significantly positive correlation with those of bioavailable phosphorus in the open area of the Meiliang *** the {2. resuspension induced by wind and wave, BAP concentrations increased in a short-term, indicating that the riverine P inputs mainly contribute to the concentrations of BAP in the estuarine water while internal P release was the major source of BAP in the open lake area. In the eutrophic shallow lake, the blooms of alga may cause pH increase and further result in internal P release. The above results showed that the new membrane of FeO/CAM can be used to monitor the concentrations of BAP and provide the scientific justifications for the control strategy of the lake eutrophication.

关键词： phosphorus, bioavailability, eutrophication, resuspension, Taihu Lake.

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Power functions with low uniformity on odd characteristic finite fields

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Science china Mathematics 2010年第8期53卷 1931-1940页

作者： ZHA ZhengBang 1,3 & WANG XueLi 2.1 school of Mathematical sciences,Luoyang {2. university,Luoyang 47102.,china 2.school of Mathematical sciences,South china {2. university,Guangzhou 510631,china 3 State key {12. of Information Security,Graduate university of Chinese Academy of sciences,beijing 100049,china 1. school of Mathematical sciences Luoyang Normal University Luoyang 471022 China3. State Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences Beijing 100049 China2. School of Mathematical Sciences South China Normal University Guangzhou 510631 China

In this paper,we give some new low differential uniformity of some power functions defined on finite fields with odd *** corollaries of the uniformity,we obtain two families of almost perfect nonlinear functions in GF... 详细信息

关键词： almost perfect nonlinear function differential uniform function finite field

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sediment pollution and its effect on fish through food chain in the Yangtze River

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International Journal of sediment Research 2008年第4期23卷 338-347页

Suspended sediment adsorbs pollutants from flowing water in rivers and deposits onto the bed. However, the pollutants accumulated in the river bed sediment may affect the bio-community through food chain for a long period of time. To study the problem the concentration of heavy metals (Cr, Cd, Hg, Cu, Fe, Zn, Pb and As) in water, sediment, and fish/invertebrate were investigated in the middle and lower reaches of the Yangtze River during 2.06-2.07. The concentrations of heavy metals were 100-10,000 times higher in the sediment than in the water. Benthic invertebrates had relatively high concentrations of heavy metals in their tissues due to their proximity to contaminated sediments. Benthic invertivore fish had moderately high concentrations of heavy metals whereas phytoplanktivore fish, such as the silver carp, accumulated the lowest concentration of heavy metals. The concentrations of Cu, Zn, and Fe were higher than Hg, Pb, Cd, Cr, and As in the tissue samples. The concentration of heavy metals was lower in the river sediments than in the lake sediments. Conversely, the concentration of heavy metals was higher in river water than in lake water. While a pollution event into a water body is often transitory, the effects of the pollutants may be long-lived due to their tendency to be absorbed in the sediments and then released into the food chain. The heavy metals were concentrated in the following order: bottom material > demersal fish and benthic fauna > middle-lower layer fish > upper-middle layer fish > water.

关键词： sediment pollution Heavy metal Fish Invertebrate Yangtze River

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Feature extraction without phase error for THz reflective spectroscopy

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Science china(Information sciences) 2012年第1期55卷 127-132页

作者： ZHANG LiangLiang,ZHONG Hua,ZHU DeChong,ZUO Jian&ZHANG CunLin beijing key {2. for Terahertz Spectroscopy and Imaging,key {2. of Terahertz Optoelectronics,ministry of education of china,Capital normal university,beijing 100048,china 1. beijing key {2. for Terahertz Spectroscopy and Imaging Key Laboratory of Terahertz Optoelectronics Ministry of Education of China Capital Normal University Beijing 100048 China

We propose two methods for avoiding misplacement phase error in terahertz reflection time-domain spectroscopy(THz-RTDS).The absorption signatures of the materials are extracted directly from the second-order derivative of the phase of the sample beam or the first derivative of the relative reflectance with respect to *** techniques provide straightforward and fast solutions to solve the phase-retrieval problem in RTDS.

关键词： feature extraction phase error reflective spectroscopy

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Evidence from carbon isotope measurements for biological origins of individual long-chain n-alkanes in sediments from the Nansha Sea,china

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Chinese Science Bulletin 2002年第7期47卷 578-581页

作者： DUAN Yi & WANG ZhipingState key laboratory of Gas Geochemistry, Lanzhou Institute of Geology, Chinese Academy of {2., Lanzhou 730000, china Institute of environmental Science, beijing normal university, beijing 100875, china 1. State key laboratory of Gas Geochemistry Lanzhou Institute of Geology Chinese Academy of Sciences 730000 Lanzhou China 2. Institute of environmental Science Beijing Normal University 100875 Beijing China

Carbon isotopes are measured for individual long-chain n-alkanes in sediments from the Nansha Sea. The features of carbon isotopic compositions of individual n-alkanes and their origins are studied. The results show that the long-chain n-alkanes have a light carbon isotopic composition and a genetic feature of mixing sources, and low-latitude higher plants and microbes are considered to be their main end member sources. Based on the abundances and carbon isotopic compositions of individual n-alkanes, the fractional contributions of the two end member sources to individual n-alkanes are quantitatively calculated by using a mixing model. The obtained data indicate that the fractional contributions of the two biological sources are different in the three samples. A trend is that the contribution of microbes increases with the depth. These results provide the theory basis and quantitatively studied method for carbon isotopic applied research of individual n-alkanes.

关键词： modern marine sediment individual n-alkane carbon isotopic composition biological source.

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Spatio-temporal pattern analysis of single-trial EEG signals recorded during visual object recognition

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Science china(Information sciences) 2011年第12期54卷 2519-2527页

作者： WANG ChangMing 1 , HU XiaoPing 3 , YAO Li 1,2., XIONG Shi 2.& ZHANG JiaCai 2.1 National key laboratory of Cognitive Neuroscience and Learning,{2., beijing 100875, china 2.College of Information Science and Technology,{2., beijing 100875, china 3 Biomedical Imaging Technology Center, Emory university/Georgia Institute of Technology, Atlanta 3032., USA 1. National key laboratory of Cognitive Neuroscience and Learning Beijing Normal University Beijing 100875 China3. Biomedical Imaging Technology Center Emory University/Georgia Institute of Technology Atlanta 30322 USA2. College of Information Science and Technology Beijing Normal University Beijing 100875 China

Object discrimination is a fundamental cognitive function for human brains. In this study, we utilized an analysis approach for single-trial electroencephalography (EEG) to analyze the spatio-temporal activation patterns of visual objects processing in human brains, and attempted to apply it to discriminate different visual objects. The spatial patterns were respectively extracted from scalp EEG and the reconstructed cortical sources, while the experiment participants were perceiving 4 different categories of visual objects (faces, buildings, cats and cars). By classifying the patterns extracted from single-trial EEG, the presented visual objects could be discriminated by a computer, and the classification accuracies may provide a quantitative index to evaluate the spatial differences of the brain activations related to different visual objects. Our results demonstrated that the spatial patterns on both the scalp and the sources levels resulted in higher classification accuracies than chance rate. We also examined the classification results using temporally non-overlapping time intervals of different event-related potential (ERP) components. The temporal changes of classification accuracies may reflect the temporal distribution of the discriminative information in the EEG responses. The present pattern extraction and classification methods may compose a computational model for single-trial EEG data analysis in investigations of the spatio-temporal activation patterns for object recognition. These spatio-temporal patterns in EEG may be useful to identifying the discriminative spatial areas and time stages to improve the accuracies and efficiencies of object discrimination. In addition, investigating and utilizing humans'cognitive mechanisms of object recognition may improve computers' processing efficiency of visual information.

关键词： EEG spatio-temporal pattern object recognition single-trial analysis visual information processing

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Estimating surface evapotranspiration using combined MODIS and CBERS-02.data

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Science china(Technological sciences) 2005年第S2期48卷 145-160页

作者： XIN Xiaozhou1,2. LIU Qinhuo1, TANG Yong1,3, TIAN Guoliang1, GU Xingfa1, LI Xiaowen1,2. ZHENG Hongsheng4 & CHEN Jiayi4 1. State key laboratory of Remote Sensing Science, Institute of Remote Sensing Applications, Chinese Academy of {2., beijing 100101, china 2. Research Center for Remote Sensing and GIS, Department of Geography, beijing normal university, beijing 100875, china 3. Graduate university of Chinese Academy of {2., beijing 100039, china 4. Department of Atmospheric Physics, Peking university, beijing 100871, china 1. State key laboratory of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences 100101 Beijing China2. Research Center for Remote Sensing and GIS Department of Geography Beijing Normal University 100875 Beijing China3. Graduate University of Chinese Academy of Sciences 100039 Beijing China4. Department of Atmospheric Physics Peking University 100871 Beijing China

Spatial scale error is one of the most serious problems in the estimates of land surface heat fluxes of sensible and latent from satellite-borne data such as MODIS 1km resolution reflectance and emissive data. One of the feasible and economic ways to decrease the spatial scale error is to use high resolution land use class data together with the MODIS data. CBERS-02.data were used to produce land use class of Baiyangdian area, Hebei Province, china in the autumn of 2.04. The area ratio of each class in MODIS pixel was calculated, and used to derive the heat fluxes of the mixed pixel. The results showed that the estimated heat fluxes of soil, sensible and latent have been changed remarkably after using the high resolution land class data. It could be concluded from the comparison between simulated and ground-measured fluxes as well as the theoretical analysis that high resolution land class data are useful to diminishing the scale error of heat fluxes estimated from low resolution satellite data.

关键词： surface evapotranspiration spatial scale error MODIS CBERS land class.

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Study on thermal infrared remote sensing of Yarlung Zangbo River and Bangong Co-Nujiang River suture belt in Qinghai-Tibet Plateau

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Science china(Technological sciences) 2006年第z2期49卷 108-113页

作者： BI Siwen, YAN Hao & WANG Changyao State key laboratory of Remote Sensing {2., Institute of Remote Sensing Application, Chinese Academy of {2., beijing 100101, china key laboratory of Three-Dimensional Information Acquisition and Application, ministry of education, Capital normal university, beijing 100037, china Chinese Acad Sci Inst Remote Sensing Applicat State Key Lab Remote Sensing Sci Beijing 100101 Peoples R China Capital normal Univ Minist Educ Key Lab Dimens Informat Acquisit & Applicat Beijing 100037 Peoples R China

The area change of heat abnormity is not in accordance with conclusions of former thermal infrared remote sensing studies of the Qinghai-Tibet Plateau, which were that the temperature of Yarlung Zangbo River suture belt of the southern Plateau is high and the northern temperature is low. The study result in this paper shows that the highest temperature is found in the Bangong Co-Nujiang River suture belt, the Yarlung Zangbo River suture belt temperature is the second highest, and the northern Tibet temperature is the lowest. The study demonstration area was the suture belt areas of the Yarlung Zangbo River and the Bangong Co-Nujiang River in the Qinghai-Tibet Plateau, where the land temperature of the Qinghai-Tibet Plateau and the bore temperature of field land surface were measured and the emissivity of land surface was calculated. In addition, the authors explore the mechanism of the relationship between thermal infrared remote sensing and constructing thermodynamics and reach four new conclusions about the thermodynamics of the Tibet Plateau.

关键词： Qinghai-Tibet Plateau, Yarlung Zangbo River-Bangong Co-Nujiang River, suture belt, thermal infrared remote sensing, heat abnormity.

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