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The fabrication and hydroxylation of surface defects on multi-walled carbon nanotubes (MWCNTs) are performed through a single or combined method involving hydrothermal, ultrasonic and ball-milling treatments. These treatments cannot change the tubular morphology of the graphite structure in MWCNTs but they can alter the surface defect structure on MWCNTs. Surface defects on MWCNTs can promote the hydroxylation of the MWCNTs to produce hydroxyl groups. However, these defects are difficult to hydroxylate when occupied by other functional groups, such as carboxyl groups, even though the hydroxylation processes are the same. After hydroxylation, the MWCNTs with surface defects can be employed as metal-free catalysts for the oxidative dehydrogenation of ethylbenzene using CO2 as soft oxidants. The inherent disorder or artificial skeleton defects on MWCNTs cannot directly act as catalytic active sites, but they can be hydroxylated to enhance the catalytic activity of the MWCNTs. For the same type of MWCNT defects formed after hydroxylation, the catalytic activity is closely related to the defect density. If the disorder or skeleton defects cause a higher defect density on the hydroxylated MWCNTs, the MWCNTs will exhibit a higher catalytic activity. Due to the different structures and positions of the MWCNT defect carbons, the artificial skeleton defects on MWCNTs more efficiently promote the hydroxylation of MWCNTs compared to the disorder defects, decreasing their defect density and enhancing their catalytic activity. Therefore, MWCNTs-BOH36 with skeleton defects has a catalytic activity that is twice as high as that of MWCNTs-CS-120 with disorder defects.

Ag-CeO2 nanoassemblys are prepared with a simple melamine-induced thermal decomposition method. Ag-CeO2 nanoassemblys have a structure composed of Ag nanoparticles and CeO2 nanoparticles. For Ag-CeO2 nanoassemblys, Ag introduction can partially or completely activate lattice oxygen species of CeO2 nanoparticles and however, the ease of Ag-CeO2 interface oxygen activation is strongly influenced by their pyrolysis temperature. Ag-CeO2 nanoassemblys prepared at 350 °C have only partial activation of CeO2 surface oxygen. If the calcination temperature increases to 400 °C, Ag-CeO2 nanoassemblys are fully activated to form more reducible interfacial lattice oxygen and to promote their low-temperature reductivity. Although excessive calcination temperature (500 °C) induces full activation of Ag-CeO2 interface lattice oxygen, Ag-CeO2 nanoassemblys will construct a new Ag-CeO2 interface that is relative difficult to reduce, causing a less amount of reducible interface lattice oxygen provided at higher temperature. Ag-CeO2 nanoassemblys are investigated to reveal the relationship of Ag-CeO2 interfacial oxygen activation and CO catalytic oxidation performance. Ag-CeO2 nanoassemblys with more interfacial lattice oxygen provided at lower temperature are found to have higher catalytic activity than that catalyst with the partially or excessively activated interfacial oxygen.

Automaton or table-based multi-pattern matching methods have been widely used in cloud services, i.e., virtual Firewall service, virtual IDS service, etc. In cloud, a large scale of patterns in such services are frequently updated causing by users’ joining or quitting and adjustment of security and management policies. Therefore, how to quickly and accurately update the Automaton and Table becomes an important issue. In this paper, we propose Eagle+, an incremental approach for updating the matching Automaton and Table whilst avoiding recalculating the whole patterns after each change. In Eagle+, we attain efficiency by computing only the latest update set of patterns when updating the Automaton and Table. Moreover, Eagle+ achieves accurately local updating based on three atomic operations, adding, updating and deleting, each of which modifies values on classical Aho–Corasick (AC) automaton, Set Backward Oracle Matching (SBOM) automaton and Wu–Manber (WM) table. Compared with existing pattern updating methods, Eagle+ reduces the computation complexity from O ( n 2 ) to O ( n ) . The experimental results show that Eagle+ can save nearly 72%–92% of the time consumption in updating automatons and perform 100X faster in WM table.

Co3O4/N-doped graphene is synthesized with a one-pot and low-cost thermal decomposition in air. N-doped graphene improves their reductivity and their low-temperature catalytic performance of CO oxidation. After the treatment with dry reaction gases, the treated composites show the changed chemical structure of nitrogen species from N (C)3 structure to C N C structure. After the treatment with wet reaction gases, nitrogen species on N-doped graphene are decomposed and the anchored sites of Co3O4 nanoparticles are converted into oxygenated groups. The nitrogen sites of N (C)3 structure are beneficial to promote the reversible conversion between the reduced Co2+ ions and active Co3+ ions on Co3O4 nanoparticles at low temperature, but Co3+ ions can irreversibly be converted into the reduced Co2+ ions on Co3O4 nanoparticles anchored at the nitrogen sites of C N C structure and it is more difficult to reduce Co3O4 nanoparticles anchored at oxygenated groups from the converted nitrogen species. Since CO oxidation is promoted by the reversible conversion between Co2+ ions and Co3+ ions on Co3O4 nanoparticles, Co3O4/N-doped graphene has low-temperature catalytic activity, but the composites treated with dry reaction gases require higher temperature to show catalytic activity and the composites treated with wet reaction gases show lower catalytic performance.

Surface structures of one-dimensional CeO2 nanocrystals are tuned with different cationic ions in a facile and mild hydrothermal system with formate and carbonate. The synthetic key is to control the formation of anisotropic CeO2 precursors with the anion structure of formate and carbonate. The diluted concentration of Na+ ions with NH4+ ions can induce the formation of the CeO2 nanotube (NT) precursors, and yet Na+ ions can promote the production of the CeO2 nanorod (NR) precursors. CeO2 nanocrystals are applied in CO oxidation and show a very important effect of their surface structure on their catalytic performance. CeO2 NTs have rich cerium surface with the higher concentration of Ce3+ ions and can accelerate the mobility of more surface oxygen species than CeO2 NRs with difficultly reduced rich oxygen surface. However, after silver loading, CeO2 NRs can show the higher stability of CeO2 particles, more easily activated surface of CeO2 NRs with more Ce3+ ions, the promoted production of metallic Ag nanoparticles and higher mobility of more surface oxygen species on CeO2 surface. Therefore, CeO2 NTs have a higher catalytic activity of CO oxidation and conversely, after loading Ag, Ag/CeO2 NRs show the higher catalytic performance.

As water resources have been developed, the input of water into wetlands by rivers has decreased. Thus, these wetland ecosystems are seriously threatened. The upstream reservoir must be operated in a manner that provides downstream wetlands with their ecological water requirement. Here, a method for analysing the effects of artificial water replenishment from reservoirs on wetlands is established. A hydrodynamic mathematical model was coupled by a one-dimensional longitudinal and depth-averaged two-dimensional hydrodynamic model to simulate the water replenishment process in wetlands. The results indicate that the overflow of floodwaters into wetlands may not occur if insufficient reservoir water is discharged. In contrast, if too much water is discharged, excess water will reach the wetland and cause a water shortage upstream. Furthermore, the results showed that there is a quantitative relationship between the area of water in a wetland and the flow discharged by the upstream reservoir. This analytical method provides direct data that can be used to ensure that wetlands receive enough water from reservoirs to maintain their ecological functions and to avoid wasting the water resources of upstream reservoirs.

Aedes albopictus is a vector of several human viral diseases, including dengue, chikungunya, and Zika. New control method for Aedes albopictus is needed to replace traditional methods such as chemical insecticides which induce resistance, environmental contamination and toxicity to human. In sterile insect technique (SIT), male mosquitoes are sterilized by γ-ray or X-ray irradiation before released. In this study, the relative effectiveness of X-ray irradiation as a mosquito SIT was investigated. Both pupal and adult Aedes albopictus were subjected to different radiation doses and their emergence, survivorship, longevity, induced sterility, and male mating competitiveness were evaluated. Relative to controls, irradiation had no significant effect on emergence and survivorship but significantly reduce adult longevity. Induced sterility were essentially same for both irradiated pupal and adult. At a dose of 40 Gy, 97% and 100% sterility was respectively achieved for males and females. Mating competitiveness was reduced both in adult males and those derived from pupae exposed to 40 Gy. However, populations can be suppressed by increasing the release ratio (sterile: normal). When the release ratio was 7:1, 74% of the wild population could be suppressed. Overall, the results of the present study showed that SIT based on X-Ray irradiation is scientific and feasible to control Aedes albopictus.

As the sizes of IT infrastructure continue to grow, cloud computing is a natural extension of virtualisation technologies that enable scalable management of virtual machines over a plethora of physically connected systems. The so-called virtualisation-based cloud computing paradigm offers a practical approach to green IT/clouds, which emphasise the construction and deployment of scalable, energy-efficient network software applications (NetApp) by virtue of improved utilisation of the underlying resources. The latter is typically achieved through increased sharing of hardware and data in a multi-tenant cloud architecture/environment and, as such, accentuates the critical requirement for enhanced security services as an integrated component of the virtual infrastructure management strategy. This paper analyses the key security challenges faced by contemporary green cloud computing environments, and proposes a virtualisation security assurance architecture, CyberGuarder, which is designed to address several key security problems within the 'green' cloud computing context. In particular, CyberGuarder provides three different kinds of services; namely, a virtual machine security service, a virtual network security service and a policy based trust management service. Specifically, the proposed virtual machine security service incorporates a number of new techniques which include (1) a VMM-based integrity measurement approach for NetApp trusted loading, (2) a multi-granularity NetApp isolation mechanism to enable OS user isolation, and (3) a dynamic approach to virtual machine and network isolation for multiple NetApp's based on energy-efficiency and security requirements. Secondly, a virtual network security service has been developed successfully to provide an adaptive virtual security appliance deployment in a NetApp execution environment, whereby traditional security services such as IDS and firewalls can be encapsulated as VM images and deployed over a virtual security network in accordance with the practical configuration of the virtualised infrastructure. Thirdly, a security service providing policy based trust management is proposed to facilitate access control to the resources pool and a trust federation mechanism to support/optimise task privacy and cost requirements across multiple resource pools. Preliminary studies of these services have been carried out on our iVIC platform, with promising results. As part of our ongoing research in large-scale, energy-efficient/green cloud computing, we are currently developing a virtual laboratory for our campus courses using the virtualisation infrastructure of iVIC, which incorporates the important results and experience of CyberGuarder in a practical context.

Nowadays, various promising paradigms of distributed computing over the Internet, such as Grids, P2P and Clouds, have emerged for resource sharing and collaboration. To enable resources sharing and collaboration across different domains in an open computing environment, virtual organizations (VOs) often need to be established dynamically. However, the dynamic and autonomous characteristics of participating domains pose great challenges to the security of virtual organizations. In this paper, we propose a secure collaboration service, called PEACE-VO, for dynamic virtual organizations management. The federation approach based on role mapping has extensively been used to build virtual organizations over multiple domains. However, there is a serious issue of potential policy conflicts with this approach, which brings a security threat to the participating domains. To address this issue, we first depict concepts of implicit conflicts and explicit conflicts that may exist in virtual organization collaboration policies. Then, we propose a fully distributed algorithm to detect potential policy conflicts. With this algorithm participating domains do not have to disclose their full local privacy policies, and is able to withhold malicious internal attacks. Finally, we present the system architecture of PEACE-VO and design two protocols for VO management and authorization. PEACE-VO services and protocols have successfully been implemented in the CROWN test bed. Comprehensive experimental study demonstrates that our approach is scalable and efficient.

As hydrogen, deuterium and tritium storage materials, a series of investigations of mechanical and thermal properties of titanium hydrides, deuterides and tritides have been performed, however, very limited theoretical studies of thermodynamic properties for them can be found. Based on density-functional theory (DFT) and density-functional perturbation theory (DFPT) we have discussed systematically the hydrogen isotope effects on the thermodynamic properties of TiX2 (X = H, D, and T) system. Our calculations indicate that for evaluating accurately their physical properties at absolute zero temperature, such as the equilibrium lattice constants, bulk modulus, and heat of formation, the zero-point energy correction must be taken into account. By performing the phonon calculation within quasiharmonic approximation (QHA), we obtain their vibrational free energies, vibrational entropies, and temperature dependence of specific heat, thermal expansion, and bulk modulus. Those results demonstrate that comparing with TiH2, TiT2 and TiD2 are more stable and the zero-point effects play an important role in their thermal expansion. The increase in the force constant between Ti and H causes the higher value of specific heat of TiH2 during the phase transition from FCC to FCT. In addition, comparing with available experimental values, we can conclude that QHA is feasible for describing the thermal properties of TiX2. (C) 2006 Elsevier B.V. All rights reserved.

The main goal of our key project, the CROWN Grid, is to empower in-depth integration of resources and the cooperation of researchers nationwide and worldwide. CROWN exploits a service-oriented architecture based on OGSA. In CROWN, remote service deployment is highly desirable. To the best of our knowledge, however, there is no successful solution to ensure the enabling remote and hot service deployment in grid systems. Traditionally, remote deployment is supported in a cold fashion, which results in many disadvantages, such as low efficiency. Moreover, since the deployer and the target container may be in different domains, great security challenges arise when a service is deployed to a remote container. In this paper, we present ROST, an original scheme of Remote and hOt Service deployment with Trustworthiness. By dynamically updating runtime environment configurations, ROST avoids restarting the runtime system during deployment. In addition, we include trust negotiation in ROST, which greatly increases the flexibility and security of the CROWN Grid. ROST has been successfully implemented. We conduct comprehensive experiments with real applications, and the results show that ROST is viable and significantly improves the service efficiency and quality of CROWN. We believe that the wide deployment of ROST would also benefit other grid systems.