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    Characteristics of main natural disasters and coping strategies in Shanghai(Chinese)
    CHEN Zhen-lou;WANG Jun;LIU Min;YU Li-zhong;XU Shi-yuang
    Journal of East China Normal University(Natural Sc    2008, 2008 (5): 116-125.  
    Abstract11255)      PDF (786KB)(848)      
    The paper pointed out that with global warming, sea level rising and the accelerated urbanization process, the intensity and frequency of natural disasters, and vulnerability of society and economy are growing quickly. Therefore, in order to seek effective disaster prevention and relief measures, natural disasters become hotspots for international society and academy. In Shanghai, one of the major big cities in eastern coastal areas of China, typhoons, rainstorms, storm surges and other natural disasters occur frequently, and often cause serious damages. The characteristics of these disasters are analyzed in detail. Facing the serious situation of risk mitigation and disaster prevention in Shanghai, several countermeasures should be adopted in order to improve Shanghai’s responding ability to natural disasters, which include taking strict precautions against serious natural disasters, developing disaster risk assessment methods and technologies, improving comprehensive disaster relief systems, establishing operational emergency plans, strengthening emergency shelters, relieve the disaster after-effects, promoting volunteer teams for emergency responses and rescues, carrying out disaster prevention publicity and disaster management personnel education.
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    Fe/ PZFE Nanometer Composites by High Energy Ball Milling
    QIAN Fang-zhen;JIANG Ke-yu;RUAN Jian-zhong
    Journal of East China Normal University(Natural Sc    2004, 2004 (1): 56-60.  
    Abstract10626)           
    Fe/PTFE nanometer compound was prepared by high energy ball milling. Firstly, PTFE was milled for 50h,90h,120h ,then Fe/ PTFE mixture was milled for 700h. The components were indentified by 57Fe Mossbauer spectroscopy. The Mossbauer effect studies show that the spectrum includes not only both
    sextets of bulk and interface of a-Fe ,it indicates the size of particle Fe is in the order of nanometer, but also one singlet for Fe3+, one doublet for Fe2+ , they corresponds to FeF2 and FeF3 respectively. As milling time increases,the component of interface of a-Fe disappears, meantime, the Fe3C appears. The result shows that it is helpful to produce FeF3 as PTFE was initially milled.
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    Sufficient and necessary condition for the chromatic equivalence of a class of graphs
    MA Hai-cheng, LI Sheng-gang
    Journal of East China Normal University(Natural Sc    2013, 2013 (1): 1-6.  
    Abstract7968)      PDF (195KB)(2428)      
    A necessary and sufficient condition for the adjoint equivalence of two graphs with the adjoint minimum real root at least $-$4 was given. Based on this result, a necessary and sufficient condition of the chromatic equivalence for the complement graphs of these graphs can be naturally obtained.
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    Property of an orthogonal projection matrix
    DU Kun, GU Gui-ding
    Journal of East China Normal University(Natural Sc    2012, 2012 (1): 97-99.  
    Abstract7841)      PDF (210KB)(2579)      
    In this paper we showed that for an orthogonal projection matrix with rank $k$, there exists an principal submatrix with order $k$ of the matrix, such that its Rayleigh quotient has a positive lower bound. The proof was made by using the relation of the singular values, eigenvalues and norm of matrices, as well as the properties of unitary matrix and compound matrix.
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    Properties of novel poly (aryl ether quinoxaline)s (PEQs)
    ZHAO Qiu-tang, Ding Ya-ming, HUA hui
    Journal of East China Normal University(Natural Sc    2013, 2013 (6): 134-140.  
    Abstract7595)      PDF (1409KB)(2025)      
    Novel poly(aryl ether quinoxaline)s (PEQs) were prepared via a new two-step procedure. Firstly, poly (ether benzil) (PEB) was synthesized by the polycondensation of 4,4′-difluorobenzil and 4,4′-isopropylidenediphenol. Then, PEQs were synthesized through chemical modification of PEB by 1,2-diaminobenzene and a small amount of 4,4′-oxydibenzene-1,2-diamine(OBDA). The polymers were characterized by IR, NMR, TMA and other measurements. Experiments show that these PEQs can be dissolved in common organic solvents, such as DMF and THF; these PEQs were dissolved in THF to get films which had good transmittance in the visible region (the transmittance was up to 85% at 450 nm). In addition, they also had higher glass transition temperatures (Tg>210 ℃), good thermal and mechanical properties, as well as excellent resistance to strong acid and alkali. They are expected to be useful functional materials.
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    Analysis of Remote Sensing Image Format —— GeoTIFF(Chinese)
    CHEN Duan-wei;SHU Jiong;WANG Qiang;DUAN Yu-sen
    Journal of East China Normal University(Natural Sc    2006, 2006 (2): 18-26.  
    Abstract7125)           
    GeoTIFF, a geographically extended image format of TIFF, was studied in this paper. Description and analysis were given to TIFF format, storing methods of GeoKeys, three kinds of coordinate systems supported by GeoTIFF, six GeoTags and their relationships, as well as coordinate transformation and geocoding. Advantages of GeoTIFF were explained, and its application prospect is anticipated.
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    Analysis of tidal characteristics of the tide gauges in the Changjiang Estuary
    YANG Zheng-dong, ZHU Jian-rong, WANG Biao, LIN Tang-yu
    Journal of East China Normal University(Natural Sc    2012, 2012 (3): 111-119.  
    Abstract6878)      PDF (1190KB)(5065)      
    Based on the measured water levels at Hengsha, Majiagang, Baozhen and Yonglongsha tide gauges in 2009, the tidal temporal and spatial variations, tidal constituents, tidal form and distortion at these gauges in the Changjiang Estuary were analyzed. There exist tidal daily inequalities that mainly occur during high tide levels, and are more significant during neap tides than spring tides in March and September while are more significant during spring tides than neap tides in June and December. The monthly maximum and minimum tidal ranges in each month at the tide gauges were given out statistically. The tidal range in the estuary varies monthly with two peaks: the maximum tidal range reaches the maximum values in March and September, and reaches the minimum values in June and December. The minimum tidal range reaches the maximum values in June and December, and reaches the minimum values in March and September. The tidal range in the South Branch reduced toward upstream due to the river discharge and friction. The tidal range at Yonglongsha tidal gauge is the largest among the 4 tidal gauges because the North Branch has small river discharge division ratio and funnel shape bathymetry. The tide is mainly composed by the 4 semi-diurnal tidal constituent (M 2S 2N 2K 2), 4 diurnal tidal constituent (K 1O 1P 1Q 1) and 3 shallow water tidal constituent (M 4MS 4M 6). The semi-diurnal tidal constituents M 2 and S 2 are the predominant ones, and the shallow water tidal constituents M 4 and MS 4 are apparent due to the shallow water in the estuary. The tidal form number in the South Branch is larger than 0.25, indicating where the tide is an irregular semi-diurnal tide type there, and is smaller than 0.25 in the North Branch, indicating where the tide is a regular semi-diurnal tide type. The tidal distortion coefficients in the 4 tidal gauges are all larger than 0.1, indicating that the tide at the tide gauges has significant distortion in the Changjiang Estuary, especially at Yonglongsha in the North Branch with tidal distortion coefficient 0.173.
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    Marine hazards in Shanghai coastal regions and corresponding countermeasures: Lessons from the storm surge disaster of Burma (Chinese)
    GONG Mao-xun;DU Pan-jun;XUE Zhi-gang
    Journal of East China Normal University(Natural Sc    2008, 2008 (5): 126-133.  
    Abstract6606)      PDF (2278KB)(574)      
    The paper firstly reviewed the serious storm surge disaster in Myanmar in May of this year, pointing out that global warming, leading to extreme natural disasters. Then analyzed marine hazards in Shanghai coastal regions. Their causes were identified in detail. Gave a description of the existing service for early warning and emergency control of marine hazards in Shanghai. Finally detail suggestions were put forward for countermeasures for these hazards.
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    The Growth Optimal Portfolio in a General Market Driven by Jump-diffusion Processes
    XU Zhi-yan
    Journal of East China Normal University(Natural Sc    2004, 2004 (2): 37-42.  
    Abstract6323)           
    In this paper, We generalize the results of Yan et al[1] results on the growth optimal portfolio in a market driven by jump-diffusion processes with multi-risky assets. Sufficient conditions for existence of growth optimal portfolio in this case were given.
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    Techniques for estimating click-through rates of Web advertisements: A survey
    JI Wen-di, WANG Xiao-ling, ZHOU Ao-ying
    Journal of East China Normal University(Natural Sc    2013, 2013 (3): 1-14.  
    Abstract6130)      PDF (1639KB)(7735)      
    Computational advertising is a kind of advertising mechanism which has the capability to find the most suitable ads for given users and web content, so as to advertises them accurately. Therefore, estimating click-through rate (CTR) precisely makes significant difference in the efficiency of advertising on the Internet. Ad click-through rate prediction is to estimate CTR with click log, which is influenced by the nature features of ad, the position, the page information, user properties, the reputation of advertisers and such other factors. This paper is aimed to illustrate useful CTR prediction models, including CTR models for ads of abundant history data, CTR models for rare ads or new ads and some optimization models. Finally, the implementation methods with real data set were demonstrated as examples.
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    Judd-Ofelt theory analysis and calculation(Chinese)
    LIN Liang-shu;XUE Yan-ling;JIANG Qi-cheng
    Journal of East China Normal University(Natural Sc    2008, 2008 (3): 109-114.  
    Abstract6047)      PDF (535KB)(981)      

    A clear presentation of the formulas and parameters in the Judd-Ofelt theory was given. Three intensity parameters was calculuted by the least-squares fitting method. Consequently, the algorithms of calculating the Judd-Ofelt parameters such as the oscillator strength, the spontaneous emission probability, branching ratio and radiative lifetime were discussed. Especially, three tables were given to make the complex algorithms be easily understood.

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    Click-through rate prediction of online advertisements based on probabilistic graphical model
    YUE Kun, WANG Chao-lu, ZHU Yun-lei, WU Hao, LIU Wei-yi
    Journal of East China Normal University(Natural Sc    2013, 2013 (3): 15-25.  
    Abstract5713)      PDF (1294KB)(7013)      
    CTR (Click-Through Rate) prediction can be used to improve users’ satisfaction with respect to the presented online advertisements (ads) and support effective advertising. CTR prediction is the basis for personalized recommendation of online ads. It is also necessary to re-commend ads and predict their CTRs for the users that have no historical click-through records. In this paper, we adopted BN (Bayesian network), an important probabilistic graphical model, as the framework for representing and inferring the similarity and the corresponding uncertainty of the behaviors in ad search of different users. First, we constructed the BN to reflect the similarity between users by means of statistic computations on the historical records of user’s ad search. Then, we measured the behavior similarity between the users with click-through records and those without records quantitatively based on the mechanism of BN’s probabilistic inferences. Consequently, we predicted the CTRs of ads with respect to the users without historical click-through records, in order to provide a metric for ad recommendation. We made experiments on the training data of Tencent CA from KDD Cup 2012-Track 2 and tested the effectiveness of our methods.
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    Compatibility characteristics of acellular porcine heart valve matrix co-crosslinked with procyanidins and glutaraldehyde
    MA Xu-bing, ZHAI Wan-yin, ZHANG Jia-min, ZHU Zi-yan,ZHANG Hong-feng, CHANG Jiang
    Journal of East China Normal University(Natural Sc    2013, 2013 (2): 92-102.  
    Abstract5578)      PDF (3608KB)(2868)      
    The clinical used bioprosthetic heart valves (BHVs) were prepared from biological tissues by glutaraldehyde (GA) crosslinking. But the clinical application of BHVs is limited mainly due to calcification, cytotoxicity and remaining immunogenicity. Procyanidins (PC) can crosslink acellular heart valve matrix (AHVM) through hydrogen bond formation and prevent AHVM from calcification. The aim of this study is to modify GA crosslinking method using PC co-crosslinking to produce a much ideal material with higher compatibility for BHV preparation. Porcine aortic AHVM was crosslinked by 8 mg/mL PC for 4 h and then by 1.25 mg/mL GA for 44 h. The co-crosslinked AHVM was tested for cytocompatibility, blood compatibility and immunogenicity. The results showed that the in vitro adhesion rate of valvular interstitial cells on co-crosslinked AHVM was increased by 59% (78.75%~19.75%)when compared with that of GA-crosslinking. There was no difference in hemolysis between co- and GA- or PC-crosslinked AHVM. The co-crosslinked AHVM exhibited significant anti-thrombosis effect ((193±15.5) platelets) when compared with that of GA-crosslinked ((292.6±24.93) platelets). Furthermore, co-crosslinked AHVM displayed lower immunogenicity than that of GA-crosslinked ((49.33±6.3)% vs (95.27±5.26)%, cell adhesive rate). These results suggest that co-crosslinked AHVM has high potential to be used for preparation of BHVs.
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    Research on the framework of specification for e-Textbook and e-Schoolbag
    WU Yong-he, ZHU Zhi-ting, HE Chao
    Journal of East China Normal University(Natural Sc    2012, 2012 (2): 70-80.  
    Abstract5439)      PDF (2795KB)(4836)      
    With the development of information technology, the e-Textbook and e-Schoolbag is received more concerns from the community, its promotion and popularization is becoming the trend. First, this paper analyzes the demand of e-Textbook and e-Schoolbag from perspective of research on framework of standards. Then it describes the framework of e-Textbook and e-Schoolbag, including conceptual model, system framework model, hierarchy diagram for e-Textbook and e-Schoolbag system and function model. At last, it gives architecture of standards for e-Textbook and e-Schoolbag and profiles of related standards for e-Textbook and e-schoolbag.
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    Environmental impact assessment of Qingcaosha Reservoirconstruction project in the Yangtze Estuary
    ZHANG Hongwei;;WU Jian;;CHE Yue;LI Wei;TONG Chunfu
    Journal of East China Normal University(Natural Sc    2009, 2009 (3): 38-47.  
    Abstract5393)      PDF (3244KB)(3737)      
    Based on historical and 2005-2006 field survey data, environmental impact assessment of Qingcaosha Reservoir construction project in the Yangtze Estuary was carried out. Results show that water quality in Qingcaosha is good, and the main indicators of water quality can meet the class Ⅱ of national surface water standard. There are 22 common types of plants in the study area with a vegetation cover of 11.3 km2. The aquatic biodiversity is high, and freshwater species are the main types of aquatic ecology. River basin pollution emissions, upstream runoff water quality deterioration, major construction projects and estuarine saltwater invasion may impact water quality of the reservoir. Reservoir operations optimization, delineation of source water protected areas, environmental pollution control and compensation strategy should be taken to protect the Qingcaosha area.
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    Some theorems about the H-value rule(Chinese)
    LIANG Yi-kong;CHAI Jun
    Journal of East China Normal University(Natural Sc    2008, 2008 (5): 27-34.  
    Abstract5388)      PDF (1240KB)(514)      
    Further study was given in this paper to the H value as a standard for evaluation of the quality of a security set. The H
    value in terms of its related parameters was characterized. An
    inequality which the changed H value satisfies after removing the
    "worst" security from the set was proved.
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    Simulation and analysis of Shanghai central citypopulation density in 1990-2000(Chinese)
    LIAO Bang-gu;XU Jian-gang;HAN Xue-pei;QI Yi;MEI An-xin
    Journal of East China Normal University(Natural Sc    2008, 2008 (4): 130-139.  
    Abstract5282)      PDF (956KB)(730)      
    This paper discussed population density simulation of shanghai central city in 1990-2000 based on land use, and analyzed the population distribution and change. Some steps were introduced to simulation process to improve precision, such as zoning by cluster analysis, modeling separately by zoning, gradually eliminating errors and precision controlling by street zones. Then the temporal and spatial characteristics of population density change were analyzed based on GIS. Raster overlay produced a map of population density change; concentric circle method and sector analysis method were used to show the distribution characteristics different with distance and orientation; the relationship between population density and residential land use shows the improvement of living condition in Shanghai from 1990 to 2000.
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    Efficient implementation for LDA in Mahout
    XU Bo-xi, HU Ning, CHEN Wen-bin, GAO Wei-guo, CHENG Jin
    Journal of East China Normal University(Natural Sc    2013, 2013 (3): 118-130.  
    Abstract5203)      PDF (423KB)(3626)      
    In a careful study of Latent Dirichlet Allocation (LDA)
    using Gibbs sampling and the MapReduce framework, an efficient
    implementation for LDA in Mahout was achieved. The experiments
    showed the high performance of this distributed parallel LDA
    program, and several issues about enhancing performance were
    discussed.
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    Automatic recognition and translation of english address on postal mails(Chinese)
    TU Xiao;CHEN Guo-yue;LU Yue
    Journal of East China Normal University(Natural Sc    2008, 2008 (3): 83-91.  
    Abstract5087)      PDF (764KB)(606)      

    According to the characteristics of the language used in address, rules different from those of natural languages were defined and applied to automatically recognize and translate English address on postal mails. To deal with the address got from Optical Character Recognition, an English-to-Chinese address translation method based on inexact string matching technology was proposed to recognize English address and translate it into Chinese. The experimental results showed that the present method is capable of reducing the influence of OCR error, and improving the translation performance.

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    Study on lake surface area change in the mid-lower reaches of the Yangtze River based on the remote sensing technique(Chinese)
    LIU Xin;HE Long-hua;ZHOU Chi;
    Journal of East China Normal University(Natural Sc    2008, 2008 (4): 124-129.  
    Abstract4937)      PDF (588KB)(664)      
    Spatial and temporal data of the major lake surface aera change in the mid-lower reaches of the Yangtze River were obtained and analyzed on the platform of geographical information system (GIS) by using digital topography maps and satellite remote sensing images(Landsat TM/ETM) in different periods of time. The results showed that: the total lake surface area in the mid-lower reaches of the Yangtze River reduced about2 544.51km2 from 1971 to 1988 ,and 1 151.97km2 from 1988 to 2000. This should due to both nature factors and human activity ,but the major factor was lake reclamation.
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