With the development of economic activities, marine oil pollution is becoming an increasing serious problem. Instead of dissolved in seawater, petroleum hydrocarbons are more easily enriched in sediments, which poses ...With the development of economic activities, marine oil pollution is becoming an increasing serious problem. Instead of dissolved in seawater, petroleum hydrocarbons are more easily enriched in sediments, which poses a serious threat to benthos. In this paper, the research progresses on toxicity of marine petroleum hydrocarbon for polychaetes were reviewed in recent years, including the toxic mechanism of petroleum hydrocarbons, the feeding habits, the effects of petroleum hydrocarbons on the antioxidant defense system, the nervous system damages, the molecular damages of polychaetes under the stress of petroleum hydrocarbon, the accumulation and metabolism of petroleum hydrocarbons in polychaetes. The future research direction were also prospected.展开更多
The taxonomy of Coilia has been extensively studied in China,and yet phylogenetic relationships among component taxa remain controversial.We used a PCR-based fingerprinting technique,amplified fragment length polymorp...The taxonomy of Coilia has been extensively studied in China,and yet phylogenetic relationships among component taxa remain controversial.We used a PCR-based fingerprinting technique,amplified fragment length polymorphism(AFLP) to characterize and identify all four species of Coilia in China.We examined the genetic relationships of the four species of Coilia and a subspecies of Coilia nasus with AFLP.A total of 180 AFLP loci were generated from six primer combinations,of which 76.11% were polymorphic.The mean genetic distance between pairs of taxa ranged from 0.047 to 0.596.The neighbor-joining tree and UPGMA dendrogram resolved the investigated species into three separate lineages:(1) C.mystus,(2) C.grayii and(3) C.brachygnathus,C.nasus,and C.nasus taihuensis.Phylogenetic analysis of the AFLP data is inconsistent with current morphological taxonomic systems.The AFLP data indicated a close relationship among C.brachygnathus,C.nasus taihuensis,and C.nasus.Therefore,the two species described under Coilia(C.brachygnathus and C.nasus taihuensis) are treated as synonyms of C.nasus.展开更多
This paper considers a leader-following tracking control problem for second-order multiagent systems(MASs) under measurement noises and directed communication channels.It is assumed that each follower-agent can measur...This paper considers a leader-following tracking control problem for second-order multiagent systems(MASs) under measurement noises and directed communication channels.It is assumed that each follower-agent can measure the relative positions and velocities of its neighbors in a noisy environment.Based on a novel velocity decomposition technique,a neighbor-based control law is designed to realize local control strategies for these continuous-time agents.It is shown that the proposed consensus protocol can guarantee that all the follower-agents track the active leader.In addition,this result is extended to a more general case with switching topologies.Finally,a numerical example is given for illustration.展开更多
This paper presents a method for extracting geometrical features of the joint probability density function(PDF)of two-dimensional systems based on its contour lines,with particular interests given to the number and po...This paper presents a method for extracting geometrical features of the joint probability density function(PDF)of two-dimensional systems based on its contour lines,with particular interests given to the number and position of peaks and craters.In order to detect those two types of structures,a series of horizontal planes are applied to truncate the joint PDF with contour lines generated.Starting with the analysis of contour lines in a single plane,shape characteristics of the peak and the crater can be reflected on the contour lines in the aspects of gradient direction and inclusion relationship.Aided by the properties of PDF,the information about gradient direction and inclusion relationship of contour lines can be obtained simultaneously if the contour tree is built.According to the contour tree,the contour lines can be classified as two groups.Then the corresponding relation between contour lines in different planes is discussed.Based on the corresponding relation,clustering analysis about contour lines belonging to the same group but having different heights is performed.Two sets of contour lines are finally obtained as the simplest expression of geometrical characteristics of a joint PDF.They can be used to obtain the number and position of each peak and crater.Three oscillators of different types are chosen to test this method,which shows that this method can pave the way for numerical calculation about the stochastic P-bifurcation of multi-dimensional systems.展开更多
Low correlation zone (LCZ) sequences are useful in quasi-synchronous code-division multiple access (QS-CDMA) communication systems. In this paper, a generic construction of LCZ sequences based on inter-leaved techniqu...Low correlation zone (LCZ) sequences are useful in quasi-synchronous code-division multiple access (QS-CDMA) communication systems. In this paper, a generic construction of LCZ sequences based on inter-leaved technique is investigated. Firstly, the shift sequence is shown to correspond to two-tuple balanced d-form function essentially, which results in new shift sequence. Secondly, an optimal design of p2-ary sequences over the integer residue class ring Zp2 is proposed, which improves the previous construction when p is an odd prime.展开更多
The isomorphism of polynomials (IP), one of the hard problems in multivariate public key cryptography induces an equivalence relation on a set of systems of polynomials. Then the enumeration problem of IP consists o...The isomorphism of polynomials (IP), one of the hard problems in multivariate public key cryptography induces an equivalence relation on a set of systems of polynomials. Then the enumeration problem of IP consists of counting the numbers of different classes and counting the cardinality of each class that is highly related to the scale of key space for a multivariate publi9 key cryptosystem. In this paper we show the enumeration of the equivalence classes containing ∑n-1 i=0 aiX^2qi when char(Fq) = 2, which implies that these polynomials are all weak IP instances. Moreover, we study the cardinality of an equivalence class containing the binomial aX2qi + bX2qj (i ≠ j) over Fqn without the restriction that char(Fq) = 2, which gives us a deeper understanding of finite geometry as a tool to investigate the enumeration problem of IP.展开更多
基金supported by the National Natural Science Foundation of China(No.21677065).
文摘With the development of economic activities, marine oil pollution is becoming an increasing serious problem. Instead of dissolved in seawater, petroleum hydrocarbons are more easily enriched in sediments, which poses a serious threat to benthos. In this paper, the research progresses on toxicity of marine petroleum hydrocarbon for polychaetes were reviewed in recent years, including the toxic mechanism of petroleum hydrocarbons, the feeding habits, the effects of petroleum hydrocarbons on the antioxidant defense system, the nervous system damages, the molecular damages of polychaetes under the stress of petroleum hydrocarbon, the accumulation and metabolism of petroleum hydrocarbons in polychaetes. The future research direction were also prospected.
基金Supported by the Special Research Foundation for Public Welfare Marine Program(No.200905019-1)the National Natural Science Foundation of China(Nos.30770354,40676086)
文摘The taxonomy of Coilia has been extensively studied in China,and yet phylogenetic relationships among component taxa remain controversial.We used a PCR-based fingerprinting technique,amplified fragment length polymorphism(AFLP) to characterize and identify all four species of Coilia in China.We examined the genetic relationships of the four species of Coilia and a subspecies of Coilia nasus with AFLP.A total of 180 AFLP loci were generated from six primer combinations,of which 76.11% were polymorphic.The mean genetic distance between pairs of taxa ranged from 0.047 to 0.596.The neighbor-joining tree and UPGMA dendrogram resolved the investigated species into three separate lineages:(1) C.mystus,(2) C.grayii and(3) C.brachygnathus,C.nasus,and C.nasus taihuensis.Phylogenetic analysis of the AFLP data is inconsistent with current morphological taxonomic systems.The AFLP data indicated a close relationship among C.brachygnathus,C.nasus taihuensis,and C.nasus.Therefore,the two species described under Coilia(C.brachygnathus and C.nasus taihuensis) are treated as synonyms of C.nasus.
基金supported by the National Natural Science Foundation of China under Grant No.61174070the Specialized Research Found for the Doctoral Program under Grant No.20110172110033
文摘This paper considers a leader-following tracking control problem for second-order multiagent systems(MASs) under measurement noises and directed communication channels.It is assumed that each follower-agent can measure the relative positions and velocities of its neighbors in a noisy environment.Based on a novel velocity decomposition technique,a neighbor-based control law is designed to realize local control strategies for these continuous-time agents.It is shown that the proposed consensus protocol can guarantee that all the follower-agents track the active leader.In addition,this result is extended to a more general case with switching topologies.Finally,a numerical example is given for illustration.
基金supported by the National Program on Key Basic Research Project(Grant No.2014CB046805)National Natural Science Foundation of China(Grant No.11372211).
文摘This paper presents a method for extracting geometrical features of the joint probability density function(PDF)of two-dimensional systems based on its contour lines,with particular interests given to the number and position of peaks and craters.In order to detect those two types of structures,a series of horizontal planes are applied to truncate the joint PDF with contour lines generated.Starting with the analysis of contour lines in a single plane,shape characteristics of the peak and the crater can be reflected on the contour lines in the aspects of gradient direction and inclusion relationship.Aided by the properties of PDF,the information about gradient direction and inclusion relationship of contour lines can be obtained simultaneously if the contour tree is built.According to the contour tree,the contour lines can be classified as two groups.Then the corresponding relation between contour lines in different planes is discussed.Based on the corresponding relation,clustering analysis about contour lines belonging to the same group but having different heights is performed.Two sets of contour lines are finally obtained as the simplest expression of geometrical characteristics of a joint PDF.They can be used to obtain the number and position of each peak and crater.Three oscillators of different types are chosen to test this method,which shows that this method can pave the way for numerical calculation about the stochastic P-bifurcation of multi-dimensional systems.
基金supported by the Key grant Project of Chinese Ministry of Education(Grant No.311031)the Innovative Research Team of Sichuan Province(Grant No.2011JTD0007)+1 种基金National Natural Science Foundation of China(Grant No.91218301)the Ministry of Education of Humanities and Social Science Foundation of China(Grant No.11XJCZH002)
文摘Low correlation zone (LCZ) sequences are useful in quasi-synchronous code-division multiple access (QS-CDMA) communication systems. In this paper, a generic construction of LCZ sequences based on inter-leaved technique is investigated. Firstly, the shift sequence is shown to correspond to two-tuple balanced d-form function essentially, which results in new shift sequence. Secondly, an optimal design of p2-ary sequences over the integer residue class ring Zp2 is proposed, which improves the previous construction when p is an odd prime.
基金supported by National Basic Research Program of China (973 Program)(Grant No. 2011CB302400)National Natural Science Foundation of China (Grant No. 60970152)Grand Project of Institute of Software (Grant No. YOCX285056)
文摘The isomorphism of polynomials (IP), one of the hard problems in multivariate public key cryptography induces an equivalence relation on a set of systems of polynomials. Then the enumeration problem of IP consists of counting the numbers of different classes and counting the cardinality of each class that is highly related to the scale of key space for a multivariate publi9 key cryptosystem. In this paper we show the enumeration of the equivalence classes containing ∑n-1 i=0 aiX^2qi when char(Fq) = 2, which implies that these polynomials are all weak IP instances. Moreover, we study the cardinality of an equivalence class containing the binomial aX2qi + bX2qj (i ≠ j) over Fqn without the restriction that char(Fq) = 2, which gives us a deeper understanding of finite geometry as a tool to investigate the enumeration problem of IP.