High-temperature laser scanning confocal microscopy (HT LSCM) has been applied to investigate the austenite–ferrite interface migration during cyclic phase transformations in situ in a Fe–Mn–C alloy. It has been found that during the cyclic phase transformations the transformation proceeds via the migration of existing austenite–ferrite interfaces. The interfaces migrate in a retraceable way. For the first time, the so–Called stagnant stage has been observed directly. The new in situ observations show that the interface migration rates for interfaces in different grains are comparable with each other prior to soft impingement, while the equilibrium migration distances for different interfaces can be quite different, depending on the local grain size. The average interface velocities as measured by HT LSCM are in very good agreement with the velocities derived from dilatometric data, and those are predicted by a local equilibrium transformation model. 相似文献
In this paper the influence of DC glow discharge HMDSO-N2 plasma on wettability and surface properties of Biaxial-oriented polypropylene (BOPP) polymeric surfaces, has been investigated. The effects of plasma exposure time and HMDSO percent on the surface energy and wettability of the BOPP films were characterized using Fourier transform infrared spectroscopy (FTIR), Atomic force microscopy (AFM) and contact angle measurement. A clear change in the surface energy of BOPP films due to plasma treatment was observed. In this work we report changing surface properties of BOPP films instead of plasma treatment time and HMDSO ratios. 相似文献
In this study, the electrochemical reduction reaction of copper(II) formate on the graphene/glassy carbon electrode (G/GCE) surface in the HCl (5 wt.%) was employed for fabrication of the PdCu nanostructures by galvanic displacement reaction. This method has a number of advantages including being environmentally-friendly, simplicity, inexpensiveness and fast. The PdCu nanostructures decorated on the G/GCE were fabricated in two steps: (1) electrochemical reduction reaction of copper(II) formate to Cu on the G/GCE and (2) the galvanic replacement reaction between Cu and Pd2+ ions. The physical and electrochemical properties of as-prepared PdCu/G were investigated via Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Cyclic Voltammetry, Chronoamperometry, and Electrochemical Impedance Spectroscopy. The PdCu/G compositional effect on ethanol oxidation in alkaline media is investigated. The results were shown that the catalytic activity and durability of PdCu/G catalyst are superior to those of Pd/C electrocatalyst for ethanol oxidation. The PdCu/G increased the current density 6.2 times more than Pd/C with a 50 mv negative shift in onset potential for electrooxidation of ethanol. Besides, the novel PdCu/G catalyst exhibits large electrochemically active surface area, lower apparent activation energy, higher levels of stability, poisoning tolerance, and lower charge transfer resistance compared to the Pd/C for the oxidation of ethanol. 相似文献
Vehicular ad hoc networks (VANETs) are a subset of mobile ad hoc networks that provide communication services between nearby vehicles and also between vehicles and roadside infrastructure. These networks improve road safety and accident prevention and provide entertainment for passengers of vehicles. Due to the characteristics of VANET such as self-organization, dynamic nature and fast-moving vehicles, routing in this network is a considerable challenge. Swarm intelligence algorithms (nature-inspired) such as ant colony optimization (ACO) have been proposed for developing routing protocols in VANETs. In this paper, we propose an enhanced framework for ACO protocol based on fuzzy logic for VANETs. To indicate the effectiveness and performance of our proposed protocol, the network simulator NS-2 is used for simulation. The simulation results demonstrate that our proposed protocol achieves high data packet delivery ratio and low end-to-end delay compared to traditional routing algorithms such as ACO and ad hoc on-demand distance vector (AODV).
Different parts of three plants (Primula auriculata, Fumaria vaillantii and Falcaria vulgaris) were extracted with three different solvents to yield 72 crude extracts. The phytochemical analysis (chemical screening, GC–MS) of three plants was investigated for their antioxidant and antibacterial activity using nine Gram-positive and Gram-negative bacteria. The principal antioxidant and antimicrobial components were determined using HPLC with UV detection. All extracts possessed antibacterial activity especially methanolic extracts from flowers of P. auriculata. The DPPH-radical scavenging assay exhibited high antioxidant activities in three plants (more than 80% at 50 μg). The F. vulgaris showed high content of carvacrol (29.8%) as main component. The contents of carvacrol and fumaric acid in the methanolic–water extracts were 1119 and 1966 mg/l respectively. Our results indicate that these plants would be able to promise sources of natural products with potential antibacterial and antioxidant activity. 相似文献
In order to explore the novel sensors for detection of carbon disulfide (CS2) molecule, the electronic sensitivity of Pd or Ni–SiCNT to CS2 molecule is investigated using density functional theory and dispersion-corrected density functional theory methods. The adsorption energy, charge transfer, density of states and molecular frontier orbital of all systems are also analyzed. The adsorption energy values reveal that PdSi or NiSi–SiCNT weakly adsorbed the CS2 molecule and their electronic properties do not change by adsorbing a gas molecule. While replacing C atom with Ni and Pd atoms can enhance the adsorption energy. Moreover, it is found that the electronic properties of PdC or NiC–SiCNT are changed upon exposure to the CS2 molecule. And NiC–SiCNT has more sensitivity to CS2 when compared to other considered nanotubes. Therefore, NiC–SiCNT is more suitable for detection and CS2 adsorption than other investigated nanotubes. NBO analysis reveals that electrons transfer from the CS2 molecule to the nanotube. 13C and 29Si chemical shielding tensors are computed using the gauge-independent atomic orbital method. Nuclear magnetic resonance calculations reveal that the isotropy parameters at the sites of Si nuclei which are directly bonded to the impurity atoms undergo significant changes. 相似文献
Effectiveness in the process of creating virtual organizations (VO) is an important pre-condition for having a truly dynamic VOs, in response to collaboration opportunities in fast changing market contexts. A realistic approach to materialize agility in VO creation is defined under the assumption of a VO Breeding Environment (VBE), that guarantees the preparedness of its members to quickly get engaged in collaboration processes. After a survey of past approaches and a characterization of the VBE concept, a discussion of the process and suggested functionalities towards a VO creation framework are presented in this context. Finally a list of supporting tools is described and future research challenges are pointed out. 相似文献
An automatic calibration of water quality model is developed in this research. Automatic calibration as the process to determine
the parameters appearing in the equations of a 2-dimensional, hydrodynamic, and water quality models (CE-QUAL-W2) is carried
out with Particle Swarm technique as an optimization tool. In the calibration of the CE-QUAl-W2 model, evaporation as a significant
parameter influences the thermal profile and water surface elevation in reservoir, simultaneously. Therefore to consider the
simultaneous effects of the water temperature variations on water surface elevation in the reservoir, a multi objective technique
is used to minimize the weighted sum of total deviations of temperature from field data at check points on monitoring days
and those of water surface elevation on daily monitoring period. The proposed approach overcomes the high computational efforts
required if a conventional calibration search technique was used, while retaining the quality of the final calibration results.
The automatic calibration approach is applied in temperature and water budget calibration of Karkheh reservoir in Iran. Applying
the proposed automatic calibration approach, shows the produced results by the CE-QUAL-W2 model with the calibrated coefficients
agree closely with a set of field data. 相似文献
Organizations compete in acquiring competitive resources, knowledge, and competencies. In the past, organizations applied
the acquired resources, knowledge and competencies to gain superiority and thus outperform others in getting customers and
brokering opportunities. In this manner the superior organizations forced the inferior organizations outside the market. However,
in the current market, when an opportunity is brokered, organizations need to collaborate, more than competing, by sharing
the acquired resources, knowledge, and competencies to respond to the opportunity which none of them could handle otherwise.
This means organizational strategies must now adapt to the notion of collaboration with others. One important organizational
strategy necessary in virtual organizations breeding environments (VBE) is focused on the organizational preparedness that
is required to enhance chances of participating in virtual organizations (VOs). A crucial aspect of preparedness is the establishment
of trust relationships with other member organizations to smoothen the sharing of resources, knowledge, and competence, and
in turn facilitate the organizations’ collaboration. In this paper we present the FETR: A Framework to Establish Trust Relationships among organizations in VBEs. We also present and analyze risks that can emerge and thus hamper the established
relationships among organizations. We also present the promotion of trust relationships among organizations. 相似文献
The zeolite NaA was synthesized from natural clinoptilolite as Si source and aluminum sulfate or sodium aluminate as Al source. The use of aluminum sulfate for the synthesis of zeolite A has not been reported in the literature. This study presents as the first time a synthesis approach in which the low cost and available source is used to prepare zeolite NaA. These nano particles of zeolite were prepared at different conditions in autoclave and a mixer was designed specifically for this purpose. The synthesized zeolites were characterized by instrumental analysis methods, such as X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope (SEM), transmission electron microscope (TEM) and wet chemical analysis by atomic absorption spectroscopy (AAS). Cation exchange capacity (CEC) and loss on ignition (LOI) have been also measured on the prepared samples. The influences of different parameters such as reaction time, temperature, initial gel concentration, mechanical stirring and drying conditions on the improvement of the final products were experienced and the procedure for the efficient synthesis of zeolite NaA was optimized with available quality control tests. Solubility of clinoptilolite as the Si source in alkaline solutions was also investigated. 相似文献