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Packet track and traceback mechanism against denial of service attacks

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The Journal of China Universities of Posts and Telecommunications 2008年第3期15卷 51-58页

作者： li li SHEN su-bin Institute of Information Network Technology Nanjing University of Posts and Telecommunications Nanjing 210003 China

The denial of service attack is a main type of threat on the Internet today. On the basis of path identification （Pi） and Internet control message protocol （ICMP） traceback （iTrace） methods, a packet track and traceback mechanism is proposed, which features rapid response and high accuracy. In this scheme, routers apply packet marking scheme and send traceback messages, which enables the victim to design the path tree in peace time. During attack times the victim can trace attackers back within the path tree and perform rapid packet filtering using the marking in each packet. Traceback messages overcome Pi＇s limitation, wherein too much path information is lost in path identifiers; whereas path identifiers can be used to expedite the design of the path-tree, which reduces the high overhead in iTrace. Therefore, our scheme not only synthesizes the advantages but also compromises the disadvantages of the above two methods. Simulation results with NS-2 show the validity of our scheme.

关键词： denial of service (DoS) attack traceback packet marking Pi

Peptidomimetics and metalloprotease inhibitors as anticancer drugs

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Science China Chemistry 2009年第5期52卷 535-548页

作者： su li XU WenFang School of Pharmaceutical Sciences Shandong UniversityJinan 250012China

Peptidomimetics with three types, as the structural or functional mimetics of natural active peptides, can preserve the bioactivity and improve the bioavailability and the specificity towards the targets of the lead peptides. Peptidomimetics of high bioactivity can be designed through various ways including conformation restriction, modification and non-peptide design. Recently the concentration on the de-velopment of cancer chemotherapeutic drugs was transferred from cytotoxic drugs to target-based drugs, and many proteases and peptidases that play key roles in the process of tumor genesis and development was discovered, which means that peptidomimetics as potential cancer chemotherapeu-tic drugs should be paid close attention to. Our laboratory has focused on the development of small-molecule peptidomimetic inhibitors of APN, MMPs and HDACs as target-based anticancer agents. These three zinc-dependent metalloproteinases play very important roles in the process of tumor genesis, invasion, metastasis, angiogenesis and matrix degradation, so small-molecule peptidomimetic inhibitors based on them would be quite potential in the development of chemotherapeutic drugs with high selectivity.

关键词： peptidomimetics drug design metalloproteinase inhibitors anticancer agents

Reliability analysis of urban gas transmission and distribution system based on FMEA and correlation operator

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Frontiers in Energy 2014年第4期8卷 443-448页

作者： su li Weiguo ZHOU School of Mechanical Engineering Tongji University Shanghai 200092 China

In order to improve the safety management of urban gas transmission and distribution system, failure mode and effects analysis （FMEA） was used to construct the reliability analysis system of the pipeline network. To solve the problem of subjectivity and uncertainty of the multi-expert decision making, the correlation operator was introduced into the calculation of the risk priority number （RPN）. Using FMEA along with weight analysis and expert investigation approach, the FMEA evaluation table was given, including five failure modes, risk priority numbers, failure causes and effects, as well as corrective actions. The results show that correlation operator can directly process the linguistic terms and quantify the priority of the risks.

关键词： gas transmission and distribution system risk evaluation reliability analysis failure mode and effects analysis (FMEA) correlation operator

Metallogenic Correlations for the Fe-Nb-REE Mineralization in the West Mine of the Bayan Obo Deposit, Inner Mongolia, China

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Acta Geologica Sinica(English Edition) 2018年第2期92卷 614-626页

作者： su li PENG suping China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology College of Mining and Coal Engineering Inner Mongolia University of Science and Technology

The West Mine of the Bayan Obo deposit, located in the northern-central part of Inner Mongolia, China, is enriched in Nb, rare earth elements and iron （Nb-REE-Fe） mineral resources. This paper presents a combined method to explore metallogenic correlation of the Nb-REE-Fe mineralization at the Bayan Obo West Mine. The method integrates factor analysis and Back Propagation （BP） neural network technology into processing and modeling of geological data. In this study, the Nb and REE contents of samples were transformed into discrete values to analyze the correlations among the metallogenic elements. The results show weak mineralization correlations between Nb and REEs. Nb and U are closely related in the geochemical patterns, while Fe is closely related to both Th and Mn. LREEs are an important factor for the mineralization of the Bayan Obo deposit, while Fe and Nb can be considered as the results of passive mineralization. On the basis of a metallogenic correlation analysis, the factors affecting the Fe-REE-Nb mineralization were extracted, and the Nb mineralization model was established by the BP neural network. Based on the BP neural network data computing, the variability of the Nb concentration displays a coupled multi-factor nonlinear relationship, which can be used to reveal the inherent metallogenic elemental regularities and predict the degree of element mineralization enrichment in the mining area.

关键词： Factor analysis BP neural network metallogenic correlation mineralization prediction modeling Bayan Obo deposit

PQBP1:A New Player in Metabotropic Glutamate Receptor Signaling and Synaptic Plasticity

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Neuroscience Bulletin 2021年第11期37卷 1637-1638页

作者： li-Da su Ying Shen Neuroscience Care Unit Second Affiliated Hospital of Zhejiang University School of MedicineHangzhou310009China Department of Physiology Zhejiang University School of MedicineHangzhou310058China

Group 1 metabotropic glutamate receptors(Gp1 mGluRs),comprising mGluR1 and mGluR5,are predominantly located at postsynaptic ***1 mGluRs induce the activation of phospholipase C-γ.

关键词： mGluR5 Metab Receptor

Rheological Properties of Mantle Peridotites at Yushigou in the North Qilian Mountains and Their Implicationsfor Plate Dynamics

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Acta Geologica Sinica(English Edition) 1998年第2期72卷 131-141,242页

作者： SONG Shuguang su li Xi'an Institute of Geology and Mineral Resources CAGS166 East Youyi Rd.Xi'anShaanxi 710054

Abstract: This paper discusses in detail the deformation textures, glide system, petrofabrics and olivine dislocation microstructures of mantle peridotites at Yushigou in the North Qilian Mountains, northwestern China. The peridotites have undergone high-pressure, high-temperature and low-strain rate plastic flow deformation. According to the dynamic recrystallized-grain size of olivine and the average spacing between the dislocation walls as well as the chemical composition of enstatite, the authors calculated the rheological parameters of the ancient upper mantle in the study area as follows: temperatures 1025–1093°C; pressures 3043–4278 MPa; depths 95–132 km; deviatoric stress 28–32 MPa; strain rates 0.2×10?14-2.13×10?14s?1 and equivalent viscosities 0.45×1020-4.65×1020 Pa ? s. These parameters suggest that the position where plastic flow took place was correspondent to the lowvelocity zone beneath the oceanic lithosphere and that oceanization characterized by middle-velocity (1–3 cm/a) sea-floor spreading took place in the North Qilian Mountains during the Early Palaeozoic.

关键词： oceanic mantle rocks rheology sea-floor spreading North Qilian Mountains

Opportunistic spectrum sharing in software defined wireless network

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Journal of Systems Engineering and Electronics 2014年第6期25卷 934-941页

作者： Mao Yang Yong li Depeng Jin li su lieguang Zeng Department of Electronic Engineering Tsinghua University

Over the past few decades, the world has witnessed a rapid growth in mobile and wireless networks（MWNs） which significantly change human life. However, proliferating mobile demands lead to several intractable challenges that MWN has to face. Software-defined network is expected as a promising way for future network and has captured growing attention. Network virtualization is an essential feature in software-defined wireless network（SDWN）, and it brings two new entities, physical networks and virtual networks. Accordingly, efficiently assigning spectrum resource to virtual networks is one of the fundamental problems in SDWN. Directly orienting towards the spectrum resource allocation problem, firstly, the fluctuation features of virtual network requirements in SDWN are researched, and the opportunistic spectrum sharing method is introduced to SDWN. Then, the problem is proved as NP-hardness. After that, a dynamic programming and graph theory based spectrum sharing algorithm is *** demonstrate that the opportunistic spectrum sharing method conspicuously improves the system performance up to around 20%–30% in SDWN, and the proposed algorithm achieves more efficient performance.

关键词： software-defined network(SDN) wireless virtualiza-tion opportunistic spectrum sharing dynamic programming graph theory

Expression Patterns of Nine Ammonium Transporters in Rice in Response to N Status

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Pedosphere 2012年第6期22卷 860-869页

作者： li su-Mei li Bao-Zhen SHI Wei-Ming State Key Laboratory of Soil and sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008(China) Key Laboratory of Agro-ecological Processes in subtropical Region Institute of Subtropical AgricultureChinese Academy of SciencesHunan 410125(China)

Nitrogen use efficiency （NUE） was very low in China and a loss of as much as 7070 of the applied nitrogen fertilizers was reported in high-yielding rice fields. In order to investigate the molecular basis of high-affinity ammonium transport or uptake into rice （Oryza sativa L.）, we analyzed the expression profiles of nine ammonium transporters （AMT）, three each of OsAMT1, OsAMT2 and OsAMT3, at two different N requirement stages （young seedling stage and tillering stage） of rice growth as well as the changes in these expression patterns according to external N status using real-time reverse transcription polymerase chain reaction （RT-PCR）. The results suggested that the nine OsAMT genes were expressed in different organs of rice plants, including mature roots, new roots, stems, old leaves and new leaves and that the expression patterns were organ specific and independent of the positions of the corresponding proteins in the phylogenetic tree. OsAMT1;1, 3;2 and 3;3 were expressed in the roots and shoots, primarily old leaves, OsAMT1;2 and 1;3 mainly in the roots, and OsAMT2;1, 2;2, 2;3 and 3;1 mainly in the shoots, primarily in new leaves, and relatively more in the stems than other genes. The expression patterns at the two different N requirement stages were the same; however, at the tillering stage with greater N requirements, the OsAMTs transcript levels were greater than those at the young seedling stage with low N requirements. N starvation for 48 h up-regulated OsAMT1;1, 1;2, 3;1, 3;2, 3;3 and down-regulated OsAMT1;3 mRNA abundance. Following N starvation, NH4＋ and NH4NO3 re-supply down-regulated OsAMT1;2 and 3;3 and up-regulated OsAMT1;3, whereas NO3 re-supply down-regulated OsAMT1;1 and 1;2. These suggested that the organ-specific expression pattern of OsAMT could be regulated by N requirement and external N status.

关键词： external N level gene expression growth stage N requirement plant organ

Solutions and Conditional lie-Backlund Symmetries of Quasi-linear Diffusion-Reaction Equations

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Communications in Theoretical Physics 2009年第1期51卷 6-12页

作者： ZUO su-li QU Chang-Zheng Center for Nonlinear Studies Northwest University Xi＇an 710069 China Department of Mathematics Northwest University Xi＇an 710069 China

New classes of exact solutions of the quasi-linear diffusion-reaction equations are obtained by seeking for the high-order conditional lie-Baeklund symmetries of the considered equations. The method used here extends the approaches of derivative-dependent functional separation of variables and the invariant subspace. Behavior to some solutions such as blow-up and quenching is also described.

关键词： conditional lie-Backlund symmetry exact solution quasi-linear diffusion-reaction equation