检索结果-南通市图书馆

Competitive adsorption of Cd, Cu, Hg and Pb by agricultural soils of the Changjiang and Zhujiang deltas in China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第11期8卷 1808-1815页

作者： zhang Ming-kui ZHENG Shun-an Department of Natural Resource Sciences School of Natural Resource and Environmental Sciences Zhejiang University Hangzhou 310029 China

Soils can often be contaminated simultaneously by more than one heavy metal. The sorption-desorption behavior of a metal in a soil will be affected by the presence of other metals. Therefore, selective retention and competitive adsorption of the soils to heavy metals can affect their availability and movement through the soils. In this study, the simultaneous competitive adsorption of four heavy metals (Cd, Cu, Hg, and Pb) on ten agricultural soils collected from the Changjiang and Zhujiang deltas, China was assessed. The results showed that the competition affected the behavior of heavy metal cations in such a way that the soils adsorbed less Cd and Hg, and more Pb and Cu with increasing total metal concentrations, regardless of the molar concen- tration applied. As the applied concentrations increased, Pb and Cu adsorption increased, while Cd and Hg adsorption decreased. The adsorption sequence most found was Pb>Cu>Hg>Cd. The maximum adsorption capacity for the heavy metal cations was calculated, and affected markedly by soil properties. The results suggest that Hg and Cd have higher mobility associated to the lower adsorption and that Pb and Cu present the opposite behavior. Significant correlations were found between the maximum adsorption capacity of the metals and pH value and exchangeable acid, suggesting that soil pH and exchangeable acid were key factors controlling the solubility and mobility of the metals in the agricultural soils.

关键词： Competitive adsorption Adsorption sequence Heavy metals Agricultural soils

Accurate and efficient exploit capture and classification

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2017年第5期60卷 193-209页

作者： Yu DING Tao WEI Hui XUE Yulong zhang Chao zhang Xinhui HAN Institute of Computer Science and Technology Peking University Eletrical Engineering and Computer Sciences UC Berkeley

Software exploits, especially zero-day exploits, are major security threats. Every day, security experts discover and collect numerous exploits from honeypots, malware forensics, and underground ***, no easy methods exist to classify these exploits into meaningful categories and to accelerate diagnosis as well as detailed analysis. To address this need, we present Seismo Meter, which recognizes both control-flowhijacking, and data-only attacks by combining approximate control-flow integrity, fast dynamic taint analysis and API sandboxing schemes. Once it detects an exploit incident, Seismo Meter generates a succinct data representation, called an exploit skeleton, to characterize the captured exploit. Seismo Meter then classifies the captured exploits into different exploit families by performing distance computing on the extracted *** evaluate the efficiency of Seismo Meter, we conduct a field test using exploit samples from public exploit databases, such as Metasploit, as well as wild-captured exploits. Our experiments demonstrate that Seismo Meter is a practical system that successfully detects and correctly classifies all these exploit attacks.

关键词： software security exploit classification exploit attack capture control flow integrity JIT security

Processing parameter optimization of fiber laser beam welding using an ensemble of metamodels and MOABC

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Mechanical Engineering 2022年第4期17卷 243-259页

作者： Jianzhao WU Chaoyong zhang Kunlei LIAN Jiahao SUN Shuaikun zhang State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Department of Mechanical Engineering National University of SingaporeSingapore 117575Singapore Walmart Global Technology Walmart Inc.BentonvilleAR 72712USA

In fiber laser beam welding(LBW),the selection of optimal processing parameters is challenging and plays a key role in improving the bead geometry and welding *** study proposes a multi-objective optimization framework by combining an ensemble of metamodels(EMs)with the multi-objective artificial bee colony algorithm(MOABC)to identify the optimal welding *** inverse proportional weighting method that considers the leave-one-out prediction error is presented to construct EM,which incorporates the competitive strengths of three *** constructs the correlation between processing parameters(laser power,welding speed,and distance defocus)and bead geometries(bead width,depth of penetration,neck width,and neck depth)with average errors of 10.95%,7.04%,7.63%,and 8.62%,*** the basis of EM,MOABC is employed to approximate the Pareto front,and verification experiments show that the relative errors are less than 14.67%.Furthermore,the main effect and the interaction effect of processing parameters on bead geometries are *** demonstrate that the proposed EM-MOABC is effective in guiding actual fiber LBW applications.

关键词： laser beam welding parameter optimization metamodel multi-objective

Origin of the Neoproterozoic Baijianshan Banded Iron Formation at the Southeastern Margin of the Tarim Block in NW China:Implication for an Extremely Reducing Ocean

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2022年第1期96卷 208-220页

作者： HAO Xiaoshu zhang Chuanlin zhang Huichao DING Teng YE Xiantao College of Oceanography Hohai UniversityNanjing 210024China

The Neoproterozoic banded iron formations(BIFs)were closely associated with the“Snowball Earth”during the breakup of the Rodinia,thus they played an important role in our understanding of the atmospheric and oceanic oxygen levels during this *** this contribution,the Neoproterozoic(ca.737 Ma)Baijianshan BIF at Southeast Tarim,northwestern China was *** is the dominated iron-species,which occurs as the lamina interbedded with *** BIF contains low concentrations of trace elements,and is depleted in light rare earth elements(LREEs)based on comparison with the Post-Archean Australian Shale(PAAS).In addition,the BIF exhibits slightly positive La-Eu anomalies,negligible Ce anomalies,insignificant Y anomalies,chondritic Y/Ho ratios(23-32),and slightly chondritic initial ε_(Nd)(t=737 Ma)values(−0.45 to 1.46,averaging 0.37).All these features indicate that the precipitation of Baijianshan BIF was closely related to the submarine low-T hydrothermal fluids with little detrital ***,the Baijianshan BIF is characterized by the significant enrichment of heavy Fe isotopes,with δ^(57)Fe_(IRMM-014) values ranging from 1.78‰ to 3.05‰,revealing the partial oxidation of Fe^(2+) into Fe^(3+) during the precipitation of this *** data suggest that the formation of Baijianshan BIF was closely associated with a significantly reducing ocean,which most likely was isolated from the oxidized atmosphere by a local ice *** Neoproterozoic Baijianshan ocean has the initial oxygen levels as low as,or even lower than that of Archean and Paleoproterozoic oceans.

关键词： Neoproterozoic banded iron formations(BIFs) Sr-Nd isotope Fe isotope Tarim Block

Mesoporous molecular sieve confined phase change materials with high absorption,enhanced thermal conductivity,and cooling energy charging/discharging capacity

在线全文

学校读者我要写书评

暂无评论

Frontiers of Materials Science 2024年第1期18卷 1-14页

作者： Qi zhang Chongyang Liu Xuehong Wu Xueling zhang Jun Song School of Energy and Power Engineering Zhengzhou University of Light IndustryZhengzhou 450007China

The biggest challenge for organic phase change materials(PCMs)used in cold energy storage is to maintain high heat storage capacity while reducing the leakage risk of PCMs during the phase transition *** is crucial for expanding their applications in the more demanding cold storage *** this study,novel formstable low-temperature composite PCMs are prepared with mesoporous materials,namely SBA-15 and CMK-3(which are prepared using the template method),as supporting matrices and dodecane as the *** to the combined effects of capillary forces within mesoporous materials and interactions among dodecane molecules,both dodecane/SBA-15 and dodecane/CMK-3 exhibit outstanding shape stability and thermal cycling stability even after 200 heating/cooling *** comparison to those of dodecane/SBA-15,dodecane/CMK-3 exhibits superior cold storage performance and higher thermal ***,the phase transition temperature of dodecane/CMK-3 is-8.81℃ with a latent heat of 122.4 J·g^(-1).Additionally,it has a thermal conductivity of 1.21 W·m^(-1)·K^(-1),which is 9.45 times that of dodecane *** these highlight its significant potential for applications in the area of cold energy storage.

关键词： cold energy storage phase change material mesoporous molecular sieve CMK-3 SBA-15 cooling energy charging/discharging capacity

CONVERGENCE ANALYSIS OF PARAREAL ALGORITHM BASED ON MILSTEIN SCHEME FOR STOCHASTIC DIFFERENTIAL EQUATIONS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2020年第3期38卷 487-501页

作者： Liying zhang Jing Wang Weien Zhou Landong Liu Li zhang School of Mathematical Science China University of Mining and TechnologyBeijing 100083China National Innovation Institute of Defense Technology Chinese Academy of Military ScienceBeijing 100101China Department of Foundation Courses Beijing Union UniversityBeijing 100101China

In this paper,we propose a parareal algorithm for stochastic differential equations(SDEs),which proceeds as a two-level temporal parallelizable integrator with the Milstein scheme as the coarse propagator and the exact solution as the fine *** convergence order of the proposed algorithm is analyzed under some regular ***,numerical experiments are dedicated to illustrate the convergence and the convergence order with respect to the iteration number k,which show the efficiency of the proposed method.

关键词： Stochastic differential equations Parareal algorithm Convergence Stochastic Taylor expansion Milstein scheme

High-quality haplotype-resolved genome assembly of cultivated octoploid strawberry

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Horticulture Research 2023年第1期10卷 299-310页

作者： Jianxin Mao Yan Wang Baotian Wang Jiqi Li Chao zhang Wenshuo zhang Xue Li Jie Li Junxiang zhang He Li Zhihong zhang Liaoning Key Laboratory of Strawberry Breeding and Cultivation College of HorticultureShenyang Agricultural University120 Dongling RoadShenyang 110866China Laboratory of Protected Horticulture(Shenyang Agricultural University) Ministry of EducationShenyang 110866China School of Information Science and Technology ShanghaiTech University393 Middle Huaxia RoadShanghai 201210China

Cultivated strawberry(Fragaria×ananassa),a perennial herb belonging to the family Rosaceae,is a complex octoploid with high heterozygosity at most ***,there is no research on the haplotype of the octoploid strawberry *** we aimed to obtain a high-quality genome of the cultivated strawberry cultivar,“Yanli”,using single molecule real-time sequencing and high-throughput chromosome conformation capture ***“Yanli”genome was 823 Mb in size,with a long terminal repeat assembly index of *** genome was phased into two haplotypes,Hap1(825 Mb with contig N50 of 26.70 Mb)and Hap2(808 Mb with contig N50 of 27.51 Mb).Using the combination of Hap1 and Hap2,we obtained for the first time a haplotype-resolved genome with 56 chromosomes for the cultivated octoploid *** identified a∼10 Mb inversion and translocation on chromosome 2-1.104957 and 102356 protein-coding genes were annotated in Hap1 and Hap2,*** of the genes related to the anthocyanin biosynthesis pathway revealed the structural diversity and complexity in the expression of the alleles in the octoploid F.×ananassa *** summary,we obtained a high-quality haplotype-resolved genome assembly of F.×ananassa,which will provide the foundation for investigating gene function and evolution of the genome of cultivated octoploid strawberry.

关键词： straw cultivar resolved

Synthesis and Biological Evaluation of Novel Anthranilic Diamides Containing N-H/CH3-1H-Pyrazoie

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2020年第5期36卷 829-834页

作者： zhang Xiulan zhang Huan LIU Jingbo XIONG Lixia LI Zhengming College of Science Tianjin University of Science&TechnologyTianjin 300457P.R.China State Key Laboratory of Elemento-Organic Chemistry Institute of Elemento-Organic ChemistryNankai UniversityTianjin 300071P.R.China

In order to systematically study the structure-activity relationship of anthranilic diamides and develop insecticides with simple structure and high efficiency,a series of novel anthranilic diamides containing N-H/CH3-lH-pyrazole was designed and *** chemical structures were characterized by NMR spec-tra,high resolution mass spectrometry(HRMS)or 13C NMR *** preliminary bioassay results indicated that all title compounds displayed moderate insecticidal activity against oriental armyworm(Mythinina separata)at 200 mg/L and ftmgicidal activities against six kinds of fungi at 50 mg/L,especially compound 5i showed 50%insecticidal activity at 25 mg/*** addition,some compounds exhibited certain antitumor *** was demonstrated that the introduction of CH3 group into pyrazole ring was superior to H for the insecticidal activity.

关键词： Anthranilic dianiide Insecticidal activity Fungicidal activity Antitumor activity

Rapid report of source parameters of 2023 M6.2 Jishishan,Gansu earthquake sequence

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Earth and Planetary Physics 2024年第2期8卷 436-443页

作者： ZhiGao Yang Jie Liu YingYing zhang Wen Yang XueMei zhang China Earthquake Networks Center Beijing 100045China

The M6.2 earthquake in Jishishan,Gansu Province,on December 18,2023,caused extraordinary earthquake *** was located in the northern part of the north−south seismic zone,which is a key area for earthquake monitoring in *** newly built dense strong motion stations in this area provide unprecedented conditions for high-precision earthquake relocation,especially the earthquake focal *** paper uses the newly built strong motion and traditional broadband seismic networks to relocate the source locations of the M3.0 and above aftershocks and to invert their focal *** horizontal error of earthquake location is estimated to be 0.5−1 km,and the vertical error is 1−2 *** focal depth range of aftershocks is 9.6−14.6 km,distributed in a 12-km-long strip with SSE *** in the south are more concentrated horizontally and vertically,while aftershocks in the north are more *** focal mechanisms of the main shock and aftershocks are relatively consistent,and the P-axis orientation is consistent with the regional strain *** is a seismic blank area of M3.0 and above,about 3−5 km between the main shock and *** is suggested that the energy released by the main shock rupture is concentrated in this *** on the earthquake location and focal mechanism of the main shock,it is inferred that the Northern Lajishan fault zone is the seismogenic structure of the main shock,and the main shock did not occur on the main fault,but on a secondary *** initial rupture depth and centroid depth of the main shock were 12.8 and 14.0 km,*** source rupture depth may not be the main reason for the severe earthquake disaster.

关键词： Jishishan earthquake earthquake relocation focal mechanism strong motion data