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1.
Dynamic Bandwidth Allocation and Rate Coordination for DiffServ Environment   总被引:1,自引:0,他引:1  
This paper presents a novel model for dynamic bandwidth allocation and rate coordination based on DiffServ and a bandwidth broker(BB). In this model, assignment of bandwidth was made according to a periodic trace of network characteristics per application. And adjustment of transfer rate was accomplished through negotiation with applications by a bandwidth agent. This model was evaluated using network simulator 2 (NS-2), and distinct improvements were found in respects of delay and packet loss of overall network and single flow. Finally, the model was suggested to be leveraged to multimedia applications with properties of lower delay and lower packet loss.  相似文献   

2.
1 Results We have already established a methodology of supramolecular organization of porphyrin and phthalocyanine by complementary coordination of the imidazolyl substituent to their metal centers.Since the stability constants reached a range of 1011 to 1012 M-1 in nonpolar solvents,it allowed construction of stable structures such as special pair of photosynthetic reaction center and light-harvesting antenna complex of photosynthetic bacteria.Here,we report one-dimensional array of porphyrin for the development of molecular wire and porphyrin-phthalocyanine conjugate as a molecular memory.  相似文献   

3.
Erosion behavior and mechanism of boronised steels   总被引:1,自引:0,他引:1  
  相似文献   

4.
系统地研究了L-拓扑空间中Dα-紧性的特征及其拓扑性质,证明了Dα-紧性是Dα-闭遗传的及有限可和的,讨论了Dα-紧性与强F紧性的关系.  相似文献   

5.
L-α氨基酸消旋化的结构理论探讨   总被引:2,自引:0,他引:2  
详述6种L-α-氨基酸在不同pH及温度条件下,消旋化百分率的差异,并从结构理论上进上步探讨消旋化的规律性。  相似文献   

6.
在L-闭包空间中定义了αc-准Lindelof性质,并研究了它的一些基本性质,证明了它对L-闭包空间的闭子集具有遗传性及弱拓扑不变性等。  相似文献   

7.
在L-ω空间借助ω_α-远域提出了ω_α-正则性,ω_α-正规性,ω_α-T_i(i=3,4)分离性,并且讨论了它们的一些性质。  相似文献   

8.
1 Results Molecular self-assembly of one-/two-dimensional (1D/2D) nanostructures has recently received great interest because the specific structures of crystals determine their unique physical and chemical properties. Coordination polymers contain two central components, connectors and linkers. Transition metal ions are often used as versatile connectors, with coordination numbers ranging from 2 to 7 dependant on the oxidation states of the metal ions. Multidentate ligands are often used as linkers, which can afford a wide variety of linking sites tuned binding strength and directionality. Thus, by using different connectors and linkers, one can design and prepare large amount of 1D, 2D and 3D coordination polymers with various structural frameworks.  相似文献   

9.
1 Results Complexation between polymer and metal cation is one of the most active and important areas of polymer science,and almost all complexed polymers were obtained in solutions[1-3].However,this method is rather limited to employ in material processing and applications.In our previous work,complexation between nitrile rubber (NBR) and CuSO4 in polymer bulk have been achieved for the first time.In this paper,complexation between NBR and ZnCl2 both in bulk and in solution were studied and the different mechanisms of complexation in different media have also been proposed.  相似文献   

10.
In this paper,what causes the setting-on place of woven fabrics without adopting tension compensation is explained by means of experimental methods.Owing to that the main shaft speed and the beating speed of reed can not attain the normal values at setting-on,the warp tension and the beating force of the reed can neither reach the normal level.Therefore,the relative slippage movement of the weft against the warp during beating will be less,while the common movement of the weft together with the warp will be bigger than those at nor-mal running.As a result,the setting-on place is then  相似文献   

11.
The detailed investigation of the dynamic epidemic spreading on homogeneous and heterogeneous networks was carried out. After the analysis of the basic epidemic models, the susceptible-infected-susceptible (SIS) model on homogenous and heterogeneous networks is established, and the dynamical evolution of the density of the infected individuals in these two different kinds of networks is analyzed theoretically. It indicates that heterogeneous networks are easier to propagate for the epidemics and the leading spreading behavior is dictated by the exponential increasing in the initial outbreaks. Large-scale simulations display that the infection is much faster on heterogeneous networks than that on homogeneous ones. It means that the network topology can have a significant effect on the epidemics taking place on complex networks. Some containment strategies of epidemic outbreaks are presented according to the theoretical analyses and numerical simulations.  相似文献   

12.
ERP dissociations between implicit and explicit memory have been confirmed by a large amount of evidence in theories of human memory. However, similarities between the two forms of memory have scarcely been studied. A possibility is that while implicit memory and explicit memory have independ- ent components, they might additionally have shared components. To explore this question, an ERP experiment was conducted with a study-to-test paradigm, in which participants performed a "shallow" (color) study task or a "deep" (pleasant) study task, followed by either a lexical decision (implicit) test (Section 1) or a recognition (explicit) test (Section 2). An interference task was performed concurrently with either the encoding or the retrieval phase of the memory task for encoding interference condition or retrieval interference condition. We compared ERP signatures of implicit and explicit memory as a function of depth of processing or interference. Under the action of the same variables, 300―500 ms old/new ERP effects of implicit and explicit memory showed the same trend. These effects maybe all link with a perceptual representational system. 500―700 ms old/new ERP effects of the two memories were dissociated. They may probably reflect voluntary and involuntary recollection respectively. These results suggested that implicit and explicit memories are not completely independent of each other, but have both independent and shared components.  相似文献   

13.
Dynamic spreading behavior of homogeneous and heterogeneous networks   总被引:1,自引:0,他引:1  
The detailed investigation of the dynamic epidemic spreading on homogeneous and heterogeneous networks was carried out. After the analysis of the basic epidemic models, the susceptible-infected-susceptible (SIS) model on homogenous and heterogeneous networks is established, and the dynamical evolution of the density of the infected individuals in these two different kinds of networks is analyzed theoretically. It indicates that heterogeneous networks are easier to propagate for the epidemics and the leading spreading behavior is dictated by the exponential increasing in the initial outbreaks. Large-scale simulations display that the infection is much faster on heterogeneous networks than that on homogeneous ones. It means that the network topology can have a significant effect on the epidemics taking place on complex networks. Some containment strategies of epidemic outbreaks are presented according to the theoretical analyses and numerical simulations.  相似文献   

14.
在L-双拓扑空间中,利用Dα-闭包定义并刻画了几种Dα-层连通性(双Dα-层连通性,弱配Dα-层连通性及配Dα-层连通性),并对它们的性质作了深入的研究.  相似文献   

15.
IntroductionFrom the emergence of SARS CoV, manystudies havebeen done on its biological medicine aspects, such aspathogeny characteristics, mechanisms of causing disease,clinic diagnosis and treatment, bacterin development andthe spreading rules. At the level of molecule biology,studies have been done on its genome sequences characteristics, structures and functions of the translatedproteins, and the evolution relationships in sequences[1 5].The caus…  相似文献   

16.
17.
The relationship between the specific surface area (SSA) of rust and the electrochemical behavior of rusted steel under wet-dry acid corrosion conditions was investigated. The results showed that the corrosion current density first increased and then decreased with increasing SSA of the rust during the corrosion process. The structure of the rust changed from single-layer to double-layer, and the γ-FeOOH content decreased in the inner layer of the rust with increasing corrosion time; by contrast, the γ-FeOOH content in the outer layer was constant. When the SSA of the rust was lower than the critical SSA corresponding to the relative humidity during the drying period, condensed water in the micropores of the rust could evaporate, which prompted the diffusion of O2 into the rust and the following formation process of γ-FeOOH, leading to an increase of corrosion current density with increasing corrosion time. However, when the SSA of the rust reached or exceeded the critical SSA, condensate water in the micro-pores of the inner layer of the rust could not evaporate which inhibited the diffusion of O2 and decreased the γ-FeOOH content in the inner rust, leading to a decrease of corrosion current density with increasing corrosion time.  相似文献   

18.
Event-related potential (ERP) was used to examine the interactions between working memory and se- lective attention. We combined two unrelated tasks, one requiring working memory and the other se- lective attention, which were performed by some undergraduates. The ERP results revealed that both congruent and incongruent stimuli in the selective attention task evoked an N400 component, reaching the peak point at around 500 ms. The N400 evoked by incongruent stimuli was more negative than that of congruent, which indicated the difference of semantic N400. Furthermore, working memory load had a significant influence on the N400 evoked by selective attention task in parietal region. And working memory load showed difference in the ERPs of working memory retrieval in central and parietal regions. The ERPs of probe under high working memory load were more positive from 350 to 550 ms post-stimulus; however, stimulus type of selective attention had no influence on working memory re- trieval. The present study shows that working memory does not play a major role in the selective at- tention, especially in ignoring distracter, but it influences the performance of the selective attention as the background. The congruency of target and distracter in the selective attention task does not influ- ence the working memory retrieval.  相似文献   

19.
Based on the non-linear differential equations of buckled pipes, the buckling behavior of pipes in different wellbores has been analyzed. The relation between the deflection of buckled pipe and the loads on it has been given, and the critical loads for sinusoidal and helical buckling within different wellbores subjected to axial and torsional loads have been determined. Therefore, the profile of load increase during the post-buckling process and the bending moments in the buckled pipe can be determined. In addition, the effects of down-hole packer as fixed end on the helical buckling behavior of pipes have been investigated. These results can be applied to the related engineering design and construction. Keywords: sinusoidal buckling, helical buck  相似文献   

20.
在L-闭包空间中定义了αc-准Lindelf性质,并研究了它的一些基本性质,证明了它对L-闭包空间的闭子集具有遗传性及弱拓扑不变性等。  相似文献   

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