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排序方式: 共有217条查询结果,搜索用时 328 毫秒
51.
52.
Amir Javad Nikkhah Omid Torabi Reza Ebrahimi-Kahrizsangi Sanaz Naghibi Amin Jamshidi 《Ceramics International》2014
Alpha-alumina–boron nitride (α-Al2O3–BN) nanocomposite was synthesized using mixtures of aluminum nitride, boron oxide and pure aluminum as raw materials via mechanochemical process under a low pressure of nitrogen gas (0.5 MPa). The phase transformation and structural evaluation during mechanochemical process were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and differential thermal analysis (DTA) techniques. The results indicated that high exothermic reaction of Al–B2O3 systems under the nitrogen pressure produced alumina, aluminum nitride (AlN), and aluminum oxynitride (Al5O6N) depending on the Al value and milling time, but no trace of boron nitride (BN) phases could be identified. On the other hand, AlN addition as a solid nitrogen source was effective in fabricating in-situ BN phase after 4 h milling process. In Al–B2O3–AlN system, the aluminothermic reaction provided sufficient heat for activating reaction between B2O3 and AlN to form BN compound. DTA analysis results showed that by increasing the activation time to 3 h, the temperature of both thermite and synthesis reactions significantly decreased and occurred as a one-step reaction. SEM and TEM observations confirmed that the range of particle size was within 100 nm. 相似文献
53.
This paper analytically investigates the thermal performance of convective–radiative T-shape fin with simultaneous variation of thermal conductivity, heat transfer coefficient and surface emissivity with temperature. Unlike some other fin studies, the sink temperatures for convection and radiation are assumed to be non-zero. This model is a more realistic representation of fins in actual engineering practice. The collection of graphs provided should facilitate design and performance evaluation of T-shaped fins. 相似文献
54.
In this article, we introduce a new metamaterial complementary electric LC resonator (CELC) and investigate its operational mechanism, characteristics, and potentialities for application in microwave components and devices, such as filters. We consider the excitation of CELC by the electric and magnetic fields of microstrip lines and its resonance characteristics by the diagrams of effective permittivity (εeff) and permeability (μeff). A circuit model is obtained by the consideration of its coupling with the loaded microstrip line. We then realize a novel left‐handed (LH) cell by the combination of the CELC resonator and a short circuited stub. It is designed by the least mean square method. We finally use the cascade connection of such LH cells for the design of a miniaturized narrow‐band band‐pass filter with high out of band rejection. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013. 相似文献
55.
Payman Shahabi Gérard Siest Bernard Herbeth Daniel Lambert Christine Masson Jean-Sébastien Hulot Sébastien Bertil Pascale Gaussem Sophie Visvikis-Siest 《International journal of molecular sciences》2013,14(8):16402-16413
We aimed to assess the association between the most common polymorphisms of cytochrome P450 (CYP) epoxygenases on the plasma levels of inflammatory markers in a population of healthy subjects. We also sought to determine whether CYP2C19*2 polymorphism is associated with the anti-inflammatory response to clopidogrel. In a population of 49 healthy young males, the baseline plasma levels of inflammatory markers including C-reactive protein, haptoglobin, orosomucoid acid, CD-40 were compared in carriers vs. non-carriers of the most frequent CYP epoxygenase polymorphisms: CYP2C9*2, CYP2C9*3, CYP2C19*2, CYP2C8*2 and CYP2J2*7. Also, the variation of inflammatory markers from baseline to 7 days after administration of 75 mg per day of clopidogrel were compared in carriers vs. non-carriers of CYP2C19* allele and also in responders vs. hypo-responders to clopidogrel, determined by platelet reactivity tests. There was no significant association between epoxygenase polymorphisms and the baseline levels of inflammatory markers. Likewise, CYP2C19* allele was not associated with anti-inflammatory response to clopidogrel. Our findings did not support the notion that the genetic variations of CYP epoxygenases are associated with the level of inflammatory markers. Moreover, our results did not support the hypothesis that CYP2C19*2 polymorphism is associated with the variability in response to the anti-inflammatory properties of clopidogrel. 相似文献
56.
Rolling-horizon and fix-and-relax heuristics for the multi-product multi-level capacitated lotsizing problem with sequence-dependent setups 总被引:1,自引:0,他引:1
M. Mohammadi S. M. T. Fatemi Ghomi B. Karimi S. A. Torabi 《Journal of Intelligent Manufacturing》2010,21(4):501-510
This paper discusses the multi-product multi-level capacitated lotsizing and scheduling problem with sequence-dependent setups.
An exact formulation of the problem is provided as a mixed-integer program which is impractical to solve in reasonable computing
time for non-small instances. To solve non-small instances of the problem, MIP-based heuristics are provided. To test the
accuracy of heuristics, two lower bounds are developed and compared against the optimal solution. The trade-offs between schedule
quality and computational time of heuristics are also provided. 相似文献
57.
Atousa Torabi Guillaume Massé Guillaume-Alexandre Bilodeau 《Computer Vision and Image Understanding》2012,116(2):210-221
In this work, we propose a new integrated framework that addresses the problems of thermal–visible video registration, sensor fusion, and people tracking for far-range videos. The video registration is based on a RANSAC trajectory-to-trajectory matching, which estimates an affine transformation matrix that maximizes the overlapping of thermal and visible foreground pixels. Sensor fusion uses the aligned images to compute sum-rule silhouettes, and then constructs thermal–visible object models. Finally, multiple object tracking uses blobs constructed in sensor fusion to output the trajectories. Results demonstrate the advantage of our proposed framework in obtaining better results for both image registration and tracking than separate image registration and tracking methods. 相似文献
58.
Sina Farahani Kasbi Seyed Hassan Jafari Hossein Ali Khonakdar Vahabodin Goodarzi Atefeh Torabi 《应用聚合物科学杂志》2020,137(45):49403
Polyamide 6 (PA6) as a cost-effective polar polymer and barium titanate (BT) as piezoelectric ceramic nanofiller were melt compounded with poly(vinylidene fluoride) (PVDF) matrix to enhance the β electroactive phase. A series of samples with two blending ratios of PVDF/PA6 (90/10 and 70/30 [wt%/wt%]) each containing 1, 3, and 5 wt% of BT were prepared. The SEM results revealed that the addition of BT to the neat blends refined the biphasic morphology which is mainly due to selective localization of BTs in PA6 dispersed phase as confirmed by TEM observation and wetting parameter predictions. The EDX analysis demonstrated a uniform distribution of BT nanoparticles in the filled systems. FTIR and XRD results showed that β content increased as a result of blending while the α phase was suppressed. The BT nanoparticles inclusion to the blends showed a synergistic effect on the β-polymorph content. These results in combination with the data derived from DSC (indicating reduction of the total crystallinity) complement the idea of β enhancement by the addition of BT nanoparticles and PA6 into PVDF. 相似文献
59.
Quantitative risk assessment is methodology based on calculating probabilities and frequencies of sequential events using Boolean algebra, and it is normally used to perform safety assessments for complex interacting systems. Although quantitative risk assessment has been commonly used in aerospace and nuclear industries, it can also be used for quantifying economic risk and for estimating possibilities of potential production losses in a petrochemical or a manufacturing plant. In developing quantitative risk assessment models for petrochemical plants, component failures as well as human (operator) errors are taken into consideration in developing the plant's fault‐tree logic, in which is used to predict probabilities of future plant upsets. This paper shows how the quantitative risk assessment can be used to rank the economic importance of the production units in a refinery for prioritizing maintenance activities. In addition, two case studies are compared to demonstrate how a quantitative risk assessment model can be used as an invaluable tool in process design optimization. The quantitative risk assessment methodology developed in this work relates production losses to the performance of the major components and the process design. This application of the quantitative risk assessment provides a basis for the risk‐informed decision‐making and optimizing allocation of plant resources in support of plant operation and maintenance activities. 相似文献
60.
A novel approach toward integration of rules into business processes using an agent-oriented framework 总被引:1,自引:0,他引:1
Every action a business process performs must be explicitly anticipated, designed for, and implemented by business professionals. The business process is dependent upon business rules (BRs) to achieve its objectives, which also involve pre- and post-conditions in the business process (BP). Most of the current techniques implement these rules directly into BPs. This will result in the BP becoming even more complicated and harder to customize. Most BRs (and laws) are buried in data warehouses as raw data. Incorporating the BRs into any BP is very complex, in terms of customization, reuse, and system integration. To overcome this problem, we propose and implement an agent-oriented framework. Using this framework, we can make the process of incorporating BR into BP less complex. The agent creates a bridge between components of the business structure, the BRs, and the BP. The BP consists of activities and sub-activities. The agent is able to communicate with BP and BRs to execute a BP. The agent can also communicate with other agents and have control over their own internal states and behavior. In this paper, we propose and implement a simple case study to execute a BP dependent upon BRs. The case study shows how the agent will synchronize, integrate, and deploy the BP. 相似文献