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排序方式: 共有156条查询结果,搜索用时 4 毫秒
71.
Mahsa Mohiti Asli Behnam Pourdeyhimi Elizabeth G. Loboa 《Macromolecular bioscience》2012,12(7):893-900
Functional PLA scaffolds are created with single component, core–sheath, or porous fiber morphology and doped with TCP nanoparticles to study the release profiles for use in bone tissue engineering applications. Pharmacokinetic analyses are performed for the three different nanofibrous structures after doping with TCP. Results indicate that single component and porous fiber scaffolds exhibit an initial‐burst release profile whereas core–sheath fibers show a steady release. All scaffolds are then seeded with human adipose‐derived stem cells (hASC), which remain viable and continue proliferation on all nanofibrous morphologies for up to 21 d. Osteogenic differentiation of hASC and cell‐mediated calcium accretion are largest on porous fibers.
72.
Reliable design of a logistics network under uncertainty: A fuzzy possibilistic-queuing model 总被引:1,自引:0,他引:1
This paper proposes a bi-objective model for designing a reliable network of bi-directional facilities in logistics network under uncertainties. For this purpose, the model utilizes an effective reliability approach to find a robust logistics network design. The objectives of the model are to minimize the total costs and the expected transportation costs after failures of bi-directional facilities of the logistics network. To solve the model, a new solution approach is proposed by combining queuing theory, fuzzy possibilistic programming and fuzzy multi-objective programming. Finally, the computational experiments are provided to illustrate the effectiveness of the proposed model and solution approach. 相似文献
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74.
An emulsification liquid phase microextraction followed by on-line phase separation coupled to high performance liquid chromatography (HPLC) is introduced based on a novel idea for the separation of dispersed organic phase from aqueous phase. In this method, the dispersed organic extraction phase was filtered using an in-line filter and it was separated from the water sample. The new approach is simple and, in addition to improving some limitations of the conventional emulsification liquid phase microextraction, eliminates the need for centrifugation in the phase separation step. 相似文献
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76.
Nakhaei Pour Ali Farshad Riyahi Mohammad Reza Housaindokht Mohammad Irani Seyed Mehdi Kamali Shahri Behnam Hatami 《Journal of Energy Chemistry》2013,22(1):119-129
The detailed kinetics of Fischer-Tropsch synthesis over an industrial Fe/Cu/La/Si catalyst was studied in a continuous spinning basket reactor under the conditions relevant to industrial operations. Reaction rate equations were derived on the basis of Langmuir-Hinshelwood-Hougen-Watson type models for Fischer-Tropsch synthesis based on possible reactions sets originated from the carbide, enolic and combined enol/carbide mechanisms. Kinetic model candidates were evaluated by the global optimization of kinetic parameters, which were realized by first minimization of multi-response objective functions with conventional Levenberg-Marquardt method. It was found that an enolic mechanism based model could produce a good fit of the experimental data. The activation energy for paraffin formation is 95 kJ·mol?1 which is smaller than that for olefin formation (121 kJ·mol?1). 相似文献
77.
Ahmad Shaabani Mozhdeh Seyyedhamzeh Ali Maleki Maryam Behnam 《Tetrahedron letters》2009,50(46):6355-4805
A new, one-pot, four-component reaction for the synthesis of a novel class of highly substituted 1,4-dihydro-1,8-naphthyridine-3-carboxamide derivatives starting from readily available inputs including aliphatic or aromatic amines, diketene, aromatic aldehydes, and 2-aminopyridines in the presence of a catalytic amount of p-toluenesulfonic acid under mild reaction conditions and in good yields at ambient temperature is described. 相似文献
78.
SPE coupled with dispersive liquid–liquid microextraction followed by GC with flame ionization detection for the determination of ultra‐trace amounts of benzodiazepines 下载免费PDF全文
Masoomeh Ghobadi Yadollah Yamini Behnam Ebrahimpour 《Journal of separation science》2014,37(3):287-294
SPE combined with dispersive liquid–liquid microextration was used for the extraction of ultra‐trace amounts of benzodiazepines (BZPs) including, diazepam, midazolam, and alprazolam, from ultra‐pure water, tap water, fruit juices, and urine samples. The analytes were adsorbed from large volume samples (60 mL) onto octadecyl silica SPE columns. After the elution of the desired compounds from sorbents with 2.0 mL acetone, 0.5 mL of eluent containing 40.0 μL chloroform was injected rapidly into 4.5 mL pure water. After extraction and centrifugation, 2 μL of the sedimented phase was injected into a GC equipped with a flame ionization detector. Several parameters affecting this process were investigated and optimized. Under the optimal conditions, LODs ranged from 0.02 to 0.05 μg/L, a linear dynamic range of 0.1–100 μg/L and relative SDs in the range of 4.4–10.7% were attained. Very high preconcentration factors ranging from 3895–7222 were achieved. The applicability of the method for the extraction of BZPs from different types of complicated matrices, such as tap water, fruit juices, and urine samples, was studied. The obtained results reveal that the proposed method is a good technique for the extraction and determination of BZPs in complex matrices. 相似文献
79.
Multi-objective OLSR for proactive routing in MANET with delay,energy, and link lifetime predictions
Zhihao Guo Shahdi Malakooti Shaya Sheikh Camelia Al-Najjar Behnam Malakooti 《Applied Mathematical Modelling》2011,35(3):1413-1426
In this paper, we develop a multi-objective approach for proactive routing in a Mobile Ad Hoc Network (MANET). We consider three routing objectives: minimizing average end-to-end delay, maximizing network energy lifetime, and maximizing packet delivery ratio. Accordingly, we develop three routing metrics: mean queuing delay on each node, energy cost on each node, and link stability on each link. For the proposed multi-objective approach, we develop efficient prediction methods: (a) predicting queuing delay and energy consumption using double exponential smoothing, and (b) predicting residual link lifetime using a heuristic of the distributions of the link lifetimes in MANET. Extensive simulation (by using ns2) is performed for the comparison of this multi-objective OLSR with existing OLSRs. The results show that the multi-objective OLSR is effective in finding optimal routing by tradeoffs among proposed objectives. 相似文献
80.
Different methods to utilize the rich library of patterns and behaviors of a chaotic system have been proposed for doing computation or communication. Since a chaotic system is intrinsically unstable and its nearby orbits diverge exponentially from each other, special attention needs to be paid to the robustness against noise of chaos-based approaches to computation. In this paper unstable periodic orbits, which form the skeleton of any chaotic system, are employed to build a model for the chaotic system to measure the sensitivity of each orbit to noise, and to select the orbits whose symbolic representations are relatively robust against the existence of noise. Furthermore, since unstable periodic orbits are extractable from time series, periodic orbit-based models can be extracted from time series too. Chaos computing can be and has been implemented on different platforms, including biological systems. In biology noise is always present; as a result having a clear model for the effects of noise on any given biological implementation has profound importance. Also, since in biology it is hard to obtain exact dynamical equations of the system under study, the time series techniques we introduce here are of critical importance. 相似文献