Fungal Infection Reduces Herbivore-Induced Plant Volatiles of Maize but does not Affect Naïve Parasitoids

Plants attacked by insects release volatile compounds that attract the herbivores' natural enemies. This so-called indirect defense is plastic and may be affected by an array of biotic and abiotic factors. We investigated the effect of fungal infection as a biotic stress agent on the emission of herbivore-induced volatiles and the possible consequences for the attraction of two parasitoid species. Maize seedlings that were simultaneously attacked by the fungus Setosphaeria turcica and larvae of Spodoptera littoralis emitted a blend of volatiles that was qualitatively similar to the blend emitted by maize that was damaged by only the herbivore, but there was a clear quantitative difference. When simultaneously challenged by fungus and herbivore, the maize plants emitted in total 47% less of the volatiles. Emissions of green leaf volatiles were unaffected. In a six-arm olfactometer, the parasitoids Cotesia marginiventris and Microplitis rufiventris responded equally well to odors of herbivore-damaged and fungus- and herbivore-damaged maize plants. Healthy and fungus-infected plants were not attractive. An additional experiment showed that the performance of S. littoralis caterpillars was not affected by the presence of the pathogen, nor was there an effect on larvae of M. rufiventris developing inside the caterpillars. Our results confirm previous indications that naïve wasps may respond primarily to the green leaf volatiles.     

Investigation of Channel‐to‐Channel Cross Convection in Serpentine Flow Fields

Channel‐to‐channel cross convection in serpentine flow fields of polymer electrolyte fuel cells (PEFC) can influence the overall cell performance. The effect strongly depends on the gas transport properties of the gas diffusion layer (GDL). For the first time measured anisotropic, compression dependent permeability and effective diffusivity of GDLs are used to quantify the influence of cross convection on the local current distribution and performance. A model was developed to examine different channel‐rib geometries and GDL characteristics. The results show that cross convection can significantly increase the current density and consequently the power density of PEFCs. A strong sensitivity to GDL compression, flow velocity and rib width was found. As an optimised case the GDL thickness under the rib was increased resulting in about 20% higher current densities. Precise knowledge of the GDL characteristics and its compression are key to understand channel‐to‐channel cross convection and optimise perfomance.     

阀体类零件加工工艺研究

文章从阀体类零件的结构、功用入手,分析其加工的工艺性,制定了合理的工艺方案,并针对加工难点制定了相应的工艺措施,形成了合理的加工工艺;经过实践验证,值得推广应用或同行借鉴。     

A Cross-Layer Approach to Enhance QoS for Multimedia Applications Over Satellite

The need for on-demand QoS support for communications over satellite is of primary importance for distributed multimedia applications. This is particularly true for the return link which is often a bottleneck due to the large set of end-users accessing a very limited uplink resource. Facing this need, Demand Assignment Multiple Access (DAMA) is a classical technique that allows satellite operators to offer various types of services, while managing the resources of the satellite system efficiently. Tackling the quality degradation and delay accumulation issues that can result from the use of these techniques, this paper proposes an instantiation of the Application Layer Framing (ALF) approach, using a cross-layer interpreter (xQoS-Interpreter). The information provided by this interpreter is used to manage the resource provided to a terminal by the satellite system in order to improve the quality of multimedia presentations from the end user’s point of view. Several experiments are carried out for different loads on the return link. Their impact on QoS is measured through different application as well as network level metrics.

国际联合教学的组织与实施——一种跨文化、跨学科、跨年级的互动教学模式

随着信息化、全球化时代的到来,以及中国大规模建设的不断持续,越来越多的国际交流在中国与境外的高校之间出现,成为当前拓展专业教育的一大契机.东南大学建筑学院近年开展了多次联合教学实践,国际联合教学已成为城市规划教育系统、严谨的教学体系之外一种具有创新性的教学组织方式,成为跨文化、跨学科、跨年级的高水平交流平台,但在实践中这一模式在与教学体系的衔接、跨年级教学的组织实施及成果展示,反馈等方面尚存在诸多改进空间,需进一步加以完善.     

观光隧道盾构叠交施工技术初探

重点介绍运用首创“盾构施工专家系统” ,实施了盾构穿越叠交点施工的技术创新和实时监控 ,填补了我国在大直径铰接式土压盾构叠交施工领域的空白。     

Primary Recrystallization of Grain Oriented Silicon Steel Strip Rolled by CSR and Annealed in Magnetic Field

The magnetic properties and textures of grain oriented silicon steel with different thickness rolled by cross shear rolling (CSR) of different mismatched speed ratio (MSR) and annealed in magnetic field under hydrogen were presented. Effects of the factors such as thickness and mismatched speed ratio on the magnetic properties and recrystallization texture were analyzed and the recrystallization principles in magnetic field annealing were discussed. The study would provide a new route for mass production of high quality ultra-thin grain oriented silicon steel strip.     

强散射体的RCS分析

用简单的强散射体制作简易的目标模拟体．以较小的反射体模拟散射较强、体积较大的目标可以有效地提高目标的生存能力,达到伪装、迷惑的目的．常见的强散射体有二面角反射体、三面角反射体等,采用矩量法计算它们的RCS,通过分析、比较和计算结果来选择合适的强散射体．     

Hydrogen storage on cross stacking nanocones

Hydrogen is one of promising energy sources with virtually non-polluting. In this paper, the hydrogenation mechanism and hydrogen storage weight percentage of new forms of CNCs, BNNCs and SiCNCs with an apex angle of 112.9° are investigated for first time using density functional theory (DFT) and applying B3LYP level at 6–31 g(d,p) basis. The calculations underscore that for all nanocones; CNCs, BNNCs and SiCNCs the convex surface is always more energetic favorite for hydrogenation comparing with the concave surface of nanocones. Also, the hydrogen storage weight percentage is always enhanced via cross stacking nanocones. Noticeably, it is found that the electron density is widely distributed up the next neighbor atoms of pentagon ring via cross stacking, however for single nanocones is mostly concentrated on the atoms of the conical part (pentagon ring). Finally, the results show that the best candidate nanocone for hydrogen storage is the cross stacking nanocones.     

Erhöhung der Energieeffizienz der Crossflow‐Filtration durch keramische Rohrmembranen einer neuen Generation

The effect of cross‐flow filtration of liquids relies on the continuous and controlled circulation of fluids in linear channels. The flow rate is of crucial importance to the economy of the process. TAMI Industries is investigating the use of so‐called additive processes to produce ceramic supports with geometric structures that cannot be produced using traditional technologies. In comparison to conventional geometries, it is possible to increase the permeate output without increasing the energy consumption or correspondingly reducing the energy consumption at the same permeate output.