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The toxicity of Cu^(2+) to Microcystis aeruginosa using dielectric spectroscopy

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Science china Chemistry 2010年第3期53卷 631-636页

作者： YU YanLi1,BAI Wei1,zhao KongShuang1& ZHOU YunLong2 1college of Chemistry,beijing normal university,beijing 100875.china 2college of life Science,beijing normal university,beijing 100875.china 1. college of Chemistry Beijing Normal University Beijing 100875 China2. College of Life Science Beijing Normal University Beijing 100875 China

Dielectric spectroscopy(DS) was utilized to investigate the toxicity of the Cu2+ solution to Microcystis *** was found that 0.04 mM Cu2+ had no effect on dielectric increment,whereas the Cu2+ concentrations above 0.1 mM decreased the value of Δε/Δε *** toxic effect of Cu2+ on *** cells was time-dependent and *** was a threshold concentration between 0.04 mM and 0.1 mM,which affected the cell membrane,suggesting that Cu2+ at the concentrations higher than 0.1 mM caused serious plasmalemma damage to *** *** addition of 1 mM Ca2+ or Mg2+ did not protect *** cells from 1 mM Cu2+ *** study demonstrates that DS monitors cell biomass facilitating observation of the toxic effects of metal ions.

关键词： Microcystis aeruginosa dielectric spectroscopy dielectric increment cupric ion toxicity

A Study of Oxalate-Induced Systemic Resistance of Muskmelon to Squash Mosaic Virus

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Advances in Manufacturing 2000年第2期4卷 171-174页

作者： zhao rong le college of life sciences, beijing normal university, beijing 100875. china college of life sciences Beijing Normal University Beijing 100875 China

By treatment with oxalate muskmelon cultivar “Wangwenxiang”, which is sensitive to squash mosaic virus (SqMV), develops systemic resistance to SqMV significantly. The challenge inoculation experiments indicate that the symptom of oxalate treated plants gets much slighter, the virus content is only 4% reduced to. The peroxidase activity increases by five times, three new isoperoxidases are induced, and lignin content increases by 82.9%. These results indicate that oxalate induces systemic resistance of muskmelon to SqMV while it induces increase of peroxidase activity, new isoperoxidases and content of lignin in the plants treated with oxalate.

关键词： oxalate muskmelon squash mosaic virus inductive resistance

Theoretical study on thermal decomposition of azoisobutyronitrile in ground state

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Science china Chemistry 2004年第5期47卷 373-380页

作者： SUN Chengke1,2, zhao Hongmei1 & LI Zonghe1 1. Department of Chemistry, beijing normal university, beijing 100875. china 2. Department of Chemistry, Qujing normal college, Qujing 655000, china 1. Department of Chemistry Beijing Normal University 100875 Beijing China 2. Department of Chemistry Qujing Normal College 655000 Qujing China

The thermal decomposition mechanisms of azoisobutyronitrile (AIBN) in the ground state have been investigated systematically. Based on the potential energy surfaces (PES) of various possible dissociation paths obtained using the semiempirical AM1 method with partial optimization, the density function theory B3LYP/6-311G* method was employed to optimize the geometric parameters of the reactants, the intermediates, the products and the transition states, which were further confirmed by the vibrational analysis. The obtained results show that the re- action process of the two-bond (three-body) simultaneous cleavage Me2(CN)C─ N=N─ C(CN)Me2? 2Me2(CN)C?+N2 is much more favorable than the reaction process of the two one- bond asynchronous cleavage Me2(CN)CN=N─C(CN)Me2 ? Me2(CN)CN=N?+ Me2(CN)C?? Me2(CN)C?+ N2. It was suggested that the electron shrinking effect of double bond (─N=N─) in AIBN and the stabilities of the Me2(CN)C?radical as well as N2 molecule are main factors of leading to the reaction proceeding in the former pathway. The calculation results were consistent with all the experimental facts.

关键词： azoisobutyronitrile, radicals, thermal decomposition, density function theory (DFT).

THE PERSISTENCE OF SOLUTIONS IN A NONLOCAL PREDATOR-PREY SYSTEM WITH A SHIFTING HABITAT

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Acta Mathematica Scientia 2024年第3期44卷 1096-1114页

作者：赵敏袁荣 School of Science Tianjin Chengjian UniversityTianjin300384China Laboratory of Mathematics and Complex Systems(Ministry of Education) School of Mathematical SciencesBeijing Normal UniversityBeijing100875China

In this paper,we mainly study the propagation properties of a nonlocal dispersal predator-prey system in a shifting *** is known that Choi et al.[J Differ Equ,2021,302:807-853]studied the persistence or extinction of the prey and of the predator separately in various moving *** particular,they achieved a complete picture in the local diffusion ***,the question of the persistence of the prey and of the predator in some intermediate moving frames in the nonlocal diffusion case was left open in Choi et al.'s *** using some a prior estimates,the Arzelà-Ascoli theorem and a diagonal extraction process,we can extend and improve the main results of Choi et *** achieve a complete picture in the nonlocal diffusion case.

关键词： predator-prey system persistence nonlocal dispersal shifting environment

Using remote sensing to research beijing wetlands dynamics

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Science china(Technological sciences) 2006年第z2期49卷 97-107页

作者： zhao Wenji, GONG zhaoning, GONG Huili, LI Xiaojuan, ZHANG Songmei & LI Jing Key Lab of Resource Environment and GIS of beijing, Capital normal university, beijing 100037, china Northeast Institute of Geography and Agroecology, Chinese Academy of sciences, Changchun 130012, china college of Resources Science and Technology, beijing normal university, beijing 100875. china Capital normal Univ Key Lab Resource Environm Beijing 100037 Peoples R China Capital normal Univ GIS Beijing Beijing 100037 Peoples R China Chinese Acad Sci NE Inst Geog & Agroecol Changchun 130012 Peoples R China beijing normal Univ Coll Resources Sci & Technol Beijing 100875 Peoples R China

In beijing, where wetlands are important to municipal freshwater conservation and biodiversity retention, three different types of wetlands were identified: riverside wetlands, wetlands surrounding lakes and reservoirs, and wetlands in municipal *** sensing technology was applied in combination with field investigations to monitor and analyze the changes in these wetlands, and a combination of fusion technologies,Landsat TM/ETM+ and IKONOS imaging, was used to investigate and map them. This study indicates that not only have wetland areas been reduced by half, but also their ecological environments have been degraded because of rapid economic development and population increase. Suggestions based on this research are made to reconstruct the ecological environment of the wetlands and return them to their previous state.

关键词： beijing, wetland resource, remote sensing technology, ecological environment, dynamics.

The Generalization of the Chinese Remainder Theorem

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Acta Mathematica Sinica,English Series 2002年第3期18卷 531-538页

作者： Li rong YU Digital Communication. Technical Research Institute. beijing 100083. P. R. china Li Bo LUO Department of Mathematics. beijing normal university. beijing 100875. P. R. china Guangdong Women’s Professional college. Guangdong 510300. P. R. china Digital Communication Technical Research Institute Beijing P. R. China Department of Mathematics Beijing Normal University Beijing P. R. China Guangdong Women's Professional college Guangdong P. R. China

We generalize the Chinese Remainder Theorem. use it to study number theory models, compare and analyse several number theory theorems in non-standard number theory models.

关键词： Non-standard number THN model Chinese Remainder Theorem

Influence of Zn ion implantation on structures and field emission properties of multi-walled carbon nanotube arrays

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Science china(Technological sciences) 2010年第3期53卷 776-781页

作者： CHEN KeFan,DENG JianHua,zhao Fei,CHENG GuoAn &ZHENG RuiTing Key Laboratory of Beam Technology and Material Modification of Ministry of Education,college of Nuclear Science and Technology,beijing normal university,beijing100875.china 1. Key Laboratory of Beam Technology and Material Modification of Ministry of Education College of Nuclear Science and Technology Beijing Normal University Beijing 100875 China

The structures and field emission properties of multi-walled carbon nanotube arrays implanted with Zn+ by MEVVA ion implanter have been *** results revealed that Zn+implantation induced structural damage and that the top of carbon nanotubes with multi-layered graphite structure were transformed into carbon nanowires with amorphous ***,C:Zn solid solution was synthesized after Zn+ *** turn-on field and threshold field were 0.80 and 1.31 V/μm,respectively for original multi-walled carbon nanotube arrays and were reduced to 0.66 and 1.04 V/μm due to the synthesis of C and Zn composite,in which the work function was reduced after low doses of Zn+*** is indicated that low doses of Zn+implantation can improve field emission performance of multi-walled carbon nanotube ***,high doses of Zn+implantation can reduce field emission properties of multi-walled carbon nanotube arrays,because radiation damage reduces the electric field enhancement factor.

关键词： multi-walled carbon nanotubes ion implantation field electron emission

Monitoring Dynamic Change of Land Cover Based on SVM and Satellite Images in Hanoi,Vietnam

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Wuhan university Journal of Natural sciences 2010年第4期15卷 355-362页

作者： zhao Jinling1,2, LIU Chuang1, 3 1. Institute of Geographic sciences and Natural Resources Research, Chinese Academy of sciences, beijing 100101, china 2. Graduate university of Chinese Academy of sciences, beijing 100049, china 3. college of Resources Science and Technology, beijing normal university, beijing 100875. china Institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing China Graduate university of Chinese Academy of sciences Beijing China college of Resources Science and Technology Beijing Normal University Beijing China

An integral method,combining support vector ma-chine (SVM) with remote-sensing analysis techniques,was ex-plored to monitor Hanoi’s dynamic change of land cover. The landsat thematic mapper (TM) image in 1993,the enhanced the-matic mapper plus (ETM+) image in 2000,and the image with the charge-coupled device camera (CCD) on the china-Brazil earth resources satellite (CBERS) in 2008 were used. Six land-cover types,including built-up areas,woodland,cropland,sand,water body and unused land,were identified. The detected results showed visually the rapid urban expansion as well as land-cover change of Hanoi from 1993 to 2008. There were 12 637.54 hm2 cropland de-creased between 1993 and 2000,and 8 227.6 hm2 cropland de-creased between 2000 and 2008. Compared with cropland,wood-land firstly decreased and then increased,and the other types did not change significantly. The results indicate that CBERS dataset has the application potential in world resources researches.

关键词： land cover the china-Brazil earth resources satellite (CBERS) support vector machine (SVM) change detection

The role of different cues in the brain mechanism on visual spatial attention

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Progress in Natural Science:Materials International 2006年第10期16卷 1045-1050页

作者： SONG Weiqun, LUO Yuejia, CHI Song, JI Xunming, LING Feng, zhao Lun, WANG Maobin and SHI Jiannong ( Department of Rehabilitation, Xuanwu Hospital, Capital university of Medical Science, beijing 100053, china State Key Laboratory of Cognitive Neuroscience and learning, beijing normal university, beijing 100875. china School of Psychology, Southwest university, Chongqing 400715, china Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of sciences, beijing 100101, china Department of Neurology, Affiliated Hospital of Qingdao university, Medical college, Qingdao 266003, china Department of Neurology, Xuanwu Hospital, Capital university of Medical Science, beijing 100053, china Institute of Linguistics, Xuzhou normal university, Xuzhou 221116, china) [a]Department of Rehabilitation Xuanwu Hospital Capital University of medical science Beijing China [b]State Key laboratory of Cognitive Neuroscience and learning Beijing Normal University Beijing China [c]School of Psychology Southwest University Chongqing China [d]Key Laboratory of Mental Health Institute of Psychology Chinese Academy of Science Beijing China [e]Department of Neurology Affiliated Hospital of Qingdao University Medical College Qingdao China [f]Department of Neurology Xuanwu Hospital Capital University of Medical Science Beijing China [g]Institute of Linguistics Xuzhou Normal University Xuzhou China

The visual spatial attention mechanism in the brain was studied in 16 young subjects through the visual search paradigm of precue-target by the event-related potential (ERP) technique, with the attentive ranges cued by different scales of Chinese character and region cues. The results showed that the response time for Chinese character cues was much longer than that for region cues especially for small region cues. With the exterior interferences, the target stimuli recognition under region cues was much quicker than that under Chinese character cues. Compared with that under region cues, targets under Chinese character cues could lead to increase of the posterior P1, decrease of the N1 and increase of the P2. It should also be noted that the differences between region cues and Chinese character cues were affected by the interference types. Under exterior interferences, no significant difference was found between region cues and Chinese character cues; however, it was not the case under the interior interferences. Considering the difference between the exterior interferences and the interior interferences, we could conclude that with the increase of difficulty in target recognition there was obvious difference in the consumption of anterior frontal resources by target stimuli under the two kinds of cues.

关键词： visual spatial attention cue scale event-related potential (ERP) Chinese character cues region cues.