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METrust: A Mutual Evaluation-based Trust Model for P2P Networks

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International Journal of Automation and computing 2012年第1期9卷 63-71页

作者： Chun-Ling Cheng xiao-long xu Bing-Zhen Gao College of Computer Nanjing University of Posts and TelecommunicationsNanjing 210003PRC

It is necessary to construct an effective trust model to build trust relationship between peers in peer-to-peer （P2P） network and enhance the security and reliability of P2P systems. The current trust models only focus on the consumers＇ evaluation to a transaction, which may be abused by malicious peers to exaggerate or slander the provider deliberately. In this paper, we propose a novel trust model based on mutual evaluation, called METrust, to suppress the peers＇ malicious behavior, such as dishonest evaluation and strategic attack. METrust considers the factors including mutual evaluation, similarity risk, time window, incentive, and punishment mechanism. The trust value is composed of the direct trust value and the recommendation trust value. In order to inhibit dishonest evaluation, both participants should give evaluation information based on peers＇ own experiences about the transaction while computing the direct trust value. In view of this, the mutual evaluation consistency factor and its time decay function are proposed. Besides, to reduce the risk of computing the recommendation trust based on the recommendations of friend peers, the similarity risk is introduced to measure the uncertainty of the similarity computing, while similarity is used to measure credibility. The experimental results show that METrust is effective, and it has advantages in the inhibition of the various malicious behaviors.

关键词： Peer-to-peer (P2P) network reputation trust model mutual evaluation similarity risk

A Multi-dimensional Index Structure Based on Improved VA-file and CAN in the Cloud

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International Journal of Automation and computing 2014年第1期11卷 109-117页

作者： Chun-Ling Cheng Chun-Ju Sun xiao-long xu Deng-Yin Zhang College of Computer Nanjing University of Posts and Telecommunications Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and TelecommunicationsMinistry of Education Jiangsu Province

Currently,the cloud computing systems use simple key-value data processing,which cannot support similarity search efectively due to lack of efcient index structures,and with the increase of dimensionality,the existing tree-like index structures could lead to the problem of"the curse of dimensionality".In this paper,a novel VF-CAN indexing scheme is ***-CAN integrates content addressable network(CAN)based routing protocol and the improved vector approximation fle(VA-fle) *** are two index levels in this scheme:global index and local *** local index VAK-fle is built for the data in each storage ***-fle is thek-means clustering result of VA-fle approximation vectors according to their degree of *** cluster forms a separate local index fle and each fle stores the approximate vectors that are contained in the *** vector of each cluster center is stored in the cluster center information fle of corresponding storage *** the global index,storage nodes are organized into an overlay network CAN,and in order to reduce the cost of calculation,only clustering information of local index is issued to the entire overlay network through the CAN *** experimental results show that VF-CAN reduces the index storage space and improves query performance efectively.

关键词： Cloud computing index similarity search clustering vector approximation fle(VA-fle) content addressable network(CAN)

Impact of climate change on wheat yield and quality in the Yellow River Basin under RCP8.5 during 2020–2050

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Advances in Climate Change Research 2022年第3期13卷 397-407页

作者： xiao-xu long Hui JU Jian-Dong WANG Shi-Hong GONG Guang-Yong LI Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agriculture SciencesBeijing 100081China College of Water Resources&Civil Engineering China Agricultural UniversityBeijing 100083China Department of Irrigation and Drainage China Institute of Water Resources and Hydropower ResearchBeijing 100048China

Studying the impact of future climate change on the yield and quality of wheat in the Yellow River Basin(YRB)is both essential for rationalizing the utilization of climate resources and ensuring national food *** this study,we employed corrected refined meteorological grid data(30 km×30 km)generated by the Climate-Weather Research and Forecasting model under RCP8.5,coupled with the DSSAT-CERES-Wheat model to predict the impact of climate change on wheat phenology,yield,and grain nitrogen content(GNC)in the YRB from 2020 to *** to the type of wheat variety and planting management in the YRB,we designed five wheat ecological regions(I-V).The results show that from 2020 to 2050,the agro-meteorological resource,involving temperature,solar radiation,and precipitation,would have an overall increasing trend during the wheat growth seasons in the *** growth period of wheat was generally shortened by approximately 8 d,including 6 d less from sowing to anthesis,and 2 d less from anthesis to *** general,the predicted wheat yield showed a decreasing trend in the YRB,with an average reduction of 0.19%over the period from 2020 to 2050 compared with the baseline period from 1975 to 2005,and the spatial variation in wheat yield change was considerably *** the future,the Qing‒Zang Spring Wheat region(V)in the western part of the YRB would be the only region with a yield increase of 35.4%,whereas the Northern Spring Wheat region(I)in the northern part of the YRB would be the region exhibiting the greatest decrease of 9.9%.Moreover,compared with the baseline,the GNC would increase by an average of 2.3%in the YRB,with a significant increase in the southern and central parts during *** GNC increase in the Huang‒Huai Winter Wheat region(III)was the highest with a 12.5%increment,but the Qing‒Zang Spring Wheat region(V)is the only region where GNC would decline,with an average decrease of 18.9%.This study implies that wheat yield and GNC have a

关键词： Yellow river basin Climate change Wheat Yield Grain nitrogen content

Human umbilical cord mesenchymal stem cells promote peripheral nerve repair via paracrine mechanisms

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Neural Regeneration Research 2015年第4期10卷 651-658页

作者： Zhi-yuan Guo xun Sun xiao-long xu Qing Zhao Jiang Peng Yu Wang Institute of Orthopedics Chinese PLA General Hospital The Neural Regeneration Co-innovation Center of Jiangsu Province

Human umbilical cord-derived mesenchymal stem cells （hUCMSCs） represent a promising young-state stem cell source for cell-based therapy. hUCMSC transplantation into the transected sciatic nerve promotes axonal regeneration and functional recovery. To further clarify the para-crine effects of hUCMSCs on nerve regeneration, we performed human cytokine antibody array analysis, which revealed that hUCMSCs express 14 important neurotrophic factors. Enzyme-linked immunosorbent assay and immunohistochemistry showed that brain-derived neurotrophic factor, glial-derived neurotrophic factor, hepatocyte growth factor, neurotrophin-3, basic fibroblast growth factor, type I collagen, fibronectin and laminin were highly expressed. Treatment with hUCMSC-conditioned medium enhanced Schwann cell viability and proliferation, increased nerve growth factor and brain-derived neurotrophic factor expression in Schwann cells, and enhanced neurite growth from dorsal root ganglion explants. These ifndings suggest that paracrine action may be a key mechanism underlying the effects of hUCMSCs in peripheral nerve repair.

关键词： nerve regeneration human umbilical cord-derived mesenchymal stem cells conditioned medium Schwann cells dorsal root ganglion axons peripheral nerve regeneration neurotrophic factors neural regeneration

Improvement of the stability of Hg/AC catalysts by CsCl for the high-temperature hydrochlorination of acetylene

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Chinese Chemical Letters 2016年第6期27卷 822-826页

作者： xiao-long xu Jia Zhao Chun-Shan Lu Tong-Tong Zhang xiao-Xia Di Shan-Chuan Gu xiao-Nian Li Institute of Industrial Catalysis of Zhejiang University of Technology State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology

Activated carbon-supported mercuric chloride（HgCl2） is used as an industrial catalyst for acetylene hydrochlorination. However, the characteristic of easy sublimation of HgCl2 leads to the deactivation o the catalyst. Here, we showed that the thermal stability of the Hg/AC catalyst can be evidently improved when Cs Cl is added into the Hg/AC catalyst. Compared with the pure Hg/AC catalyst, the sublimation rate of HgCl2 from the Hg–Cs/AC catalyst decreased significantly and the Hg–Cs/AC catalyst showed bette catalytic activity and stability in the reaction. This promoting effect is related to the existence of cesium mercuric chlorides（CsxHgyCl（x＋2y）） highlighted by XRD, HR-TEM and EDX analyses. Thus, reacting HgCl2 with alkali chlorides to form alkali-mercuric chlorides may be a key to design highly efficient and thermally stable mercuric chloride catalyst for hydrochlorination reactions.

关键词： Cesium chloride Mercuric chloride Sublimation Hydrochlorination of acetylene Cesium–mercuric chlorides

One-pot synthesis of nitrogen and sulfur co-doped activated carbon supported AuCl_3 as efficient catalysts for acetylene hydrochlorination

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Chinese Chemical Letters 2016年第9期27卷 1567-1571页

作者： xiao-Xia Di Jia Zhao Yi Yu xiao-long xu Shan-Chuan Gu Hai-Hua He Tong-Tong Zhang xiao-Nian Li Institute of Industrial Catalysis of Zhejiang University of Technology State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology

Commercialization of acetylene hydrochlorination using AuCl3 catalysts has been impeded by its poor stability. We have been studying that nitrogen-modified Au/NAC catalyst delivered a stable performance which can improve acetylene hydrochlorination activity and has resistance to catalytic deactivation. Here we show that nitrogen and sulfur co-doped activated carbon supported AuCl3 catalyst worked as efficient catalysts for the hydrochlorination of acetylene to vinyl chloride. Au/NSAC catalyst demonstrated high activity comparative to Au/AC catalyst. Furthermore, it also delivered stable performance within the selectivity of acetylene, reaching more than 99.5%, and there was only a 3.3% C2H2 conversion loss after running for 12 h under the reaction conditions of a temperature of 180 C and a C2H2 hourly space velocity of 1480 h 1. The presence of the sulfur atoms may serve to immobilize/ anchor the Au and also help prevent reduction and sintering of the Au and hence improve the catalytic activity and stability. The excellent catalytic performance of the Au/NSAC catalyst demonstrated its potential as an alternative to mercury chloride catalysts for acetylene hydrochlorination.

关键词： Acetylene Hydrochlorination AuCl3 Nitrogen and sulfur co-doped

Progress in processing of porous titanium:a review

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Rare Metals 2024年第5期43卷 1932-1955页

作者： xiao-Li Yang Xian-Feng Du Zhi-Lin xu Zhong-Shuai Liang Li-long Xiong Engineering Research Center of Energy Storage Materials and Devices Ministry of EducationSchool of ChemistryXi'an Jiaotong UniversityXi'an 710049China

As a novel structural and functional material,porous titanium and its alloys have been widely used in the aerospace,marine engineering and biomedical fields due to their high corrosion resistance,low density,good biocompatibility and excellent mechanical ***,in this paper,a comprehensive review of powder metallurgy(PM)(including additive manufacturing(AM)processes)for fabricating porous titanium is firstly covered in terms of their working principles,capabilities,shortcomings and ***,the influencing factors of various methods on final pore structure of porous Ti are ***,a summary of the chemical methods(CM)to obtain the porous Ti is also provided,such as dealloying method and reduction ***,the tendency and direction of preparation technology as well as application of porous titanium were prospected.

关键词： Porous titanium Powder metallurgy Chemical method Pore structure Processing process

Surface Polarization Effects on Collapse Transition of Polyelectrolyte Brushes

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Chinese Journal of Polymer Science 2024年第9期42卷 1313-1320,I0006页

作者： xiao-Fei xu State Key Laboratory of Chemical Engineering and School of Chemical Engineering East China University of Science and TechnologyShanghai200237China

Polyelectrolyte brushes(PEBs)are commonly used to modify surface that have attracted great research *** dielectric permittivity of the grafted surface is typically significantly different from that of solution,which results in surface polarization(SP)effect with a jump of electric *** is thus important to study how SP alters the PEB’s structure and *** this work,the SP effects on PEB structure was studied using a statistical thermodynamic *** free energy functional to describe SP effect was constructed by using the image-charge ***,the electrostatic potential was solved from a modified Poisson-Boltzmann equation taking the ion solvation effect into *** the absence of SP,the thickness of PEB exhibited a continuous collapse transition when decreasing the solvent *** the presence of SP,the collapse became a jump-like *** energy analysis showed that the long-range Coulombic interaction dominated the transition because of the enhanced counterion condensation in the presence of *** theory provides an effective tool to study SP effect on PEBs,and the results explain the underlying physics in PEB collapse transition.

关键词： Surface polarization Polyelectrolyte brush Image charge Ion solvation Polyelectrolyte collapse transition

Effects of water extract from Cornus controversa on the expression levels of DiSOC1-b and DiCCoAOMT1 genes related with the growth of dove tree seedlings

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Journal of Plant Ecology 2024年第2期17卷 62-73页

作者： xiaoyan Chen Zhengchuan Liang Yun long Jihong Pan Tingfa Dong Qinsong Liu xiao xu College of Life Science China West Normal UniversityNanchongSichuan 637009China Key Laboratory of Southwest China Wildlife Resources Conservation(China West Normal University) Ministry of EducationNanchongSichuan 637009China Academy of Agricultural Sciences Liangshan Yi Autonomous PrefectureXichangSichuan 615000China

Although characterization of plant interactions has become a research hotspot to assess the adaptability of endangered plants,the underlying molecular basis remains *** tree(Davidia involucrata)seedlings were watered with distilled water(CK),leaf water extract(0.025 g mL^(-1))and branch water extract(0.1 g mL^(-1))from Cornus controversa,***,the morphology,biomass and gene expression levels of DiSOC1-b and DiCCoAOMT1 were *** results showed that morphological traits and biomass accumulation of *** seedlings were decreased by the addition of leaf water extracts,and increased by branch water ***,the gene expression level of DiSOC1-b was signifcantly down-regulated,while the gene expression level of DiCCoAOMT1 was signifcantly up-regulated in the stems and roots of *** upon treatment with leaf water extracts of *** contrast,the gene expression level of DiSOC1-b was signifcantly up-regulated in the leaves and stems,while the gene expression level of DiCCoAOMT1 was signifcantly down-regulated in the roots of *** upon treatment with branch water extracts of *** addition,the expression level of DiSOC1-b was positively correlated with most of morphological traits and total biomass(P<0.05),while DiCCoAOMT1 was negatively correlated with the majority of morphological traits in *** seedlings(P<0.05).Taken together,these results suggest that water extracts from the leaves and branches of the *** exhibit opposite allelopathic effects and affect the expression levels of genes related to growth(DiSOC1-b)and environmental adaptability(DiCCoAOMT1)in *** seedlings.

关键词： allelopathy Davidia involucrata DiCCoAOMT1 DiSOC1-b water extract