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排序方式: 共有855条查询结果,搜索用时 31 毫秒
31.
In this paper, a new voltage-mode (VM) first-order phase shifter (all-pass filter) employing only four NMOS transistors and
minimum number of passive elements (i.e. one resistor and one capacitor) is proposed. The proposed VM phase shifter has high
input impedance and does not require passive element matching constraints. Moreover, since only two NMOS transistors are stacked
between positive and negative supply voltages, the proposed circuit is suitable for low-voltage operation. Electronic tunability
can be provided easily by replacing the employed resistor with an NMOS transistor operating in triode region. Simulation results
based on 0.18 μm TSMC CMOS parameters with ±0.9 V supply voltages are given to demonstrate the performance of the proposed
phase shifter. 相似文献
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34.
Behrouz Parsa Moghaddam José António Tenreiro Machado 《Journal of scientific computing》2017,71(3):1351-1374
This paper proposes accurate and robust algorithms for approximating variable order fractional derivatives of arbitrary order. The proposed schemes are based on finite difference approximations. We compare the performance of algorithms by introducing a new formulation of experimental convergence order. Two initial value problems are considered and solved by means of the proposed methods. Numerical results are provided justifying the usefulness of the proposed methods. 相似文献
35.
Glucose oxidase effect on treatment of textile effluent containing reactive azo dyes by Phanerochaete chrysosporium 下载免费PDF全文
36.
Majid Siavashi Hamid Garusi Shahram Derakhshan 《Numerical Heat Transfer, Part A: Applications》2017,72(9):721-744
Steam-assisted gravity drainage (SAGD) is a thermal enhanced oil recovery technique through drilling of two horizontal wells. Effects of steam injection temperature, well rates, and their distance on oil recovery were analyzed and optimized. Steam temperature and well distances remarkably affect SAGD performance. Four metaheuristic algorithms (particle swarm optimization (PSO), imperialist competitive algorithm, cultural algorithm, and Bees algorithm) and pattern search optimization algorithm (PSA) are used for optimization. PSO performs better than other metaheuristics and PSA is the fastest one, while it is probable to be trapped in local optimums. Hybrid PSO-PS is proposed that starts with PSO and proceeds with PSA, and tested in an SAGD project and showed excellence over other techniques. 相似文献
37.
Shahram Azadi Ali Jafari Masoud Samadian 《Journal of Mechanical Science and Technology》2014,28(3):837-848
Directional response and roll stability characteristics of a partly filled tractor semi-trailer vehicle, with cylindrical tank, under different parameters and conditions are investigated. The effective parameters and conditions in the stability of a tractor semi-trailer carrying liquid can be considered as filled volume, kinematic viscosity of liquid cargo and vehicle steering input. The dynamic interaction of liquid cargo with the tractor semi-trailer vehicle is evaluated by integrating a dynamic slosh model of the partly filled tank with five-degrees-offreedom of a tractor semi-trailer tank model. The dynamic fluid slosh within the tank is modeled using three-dimensional Navier-Stokes equations, coupled with the volume-of-fluid equations and analyzed using FLUENT software. The coupled tank-vehicle model is subsequently analyzed to determine the roll stability characteristics for different conditions and maneuvers. The results show effects of parameter variations on roll stability of the vehicle carrying liquid and also fluid’s behavior in interaction with a vehicle’s dynamics. 相似文献
38.
David Rivest-Hénault Reza Farrahi Moghaddam Mohamed Cheriet 《International Journal on Document Analysis and Recognition》2012,15(2):101-124
Document image binarization is a difficult task, especially for complex document images. Nonuniform background, stains, and variation in the intensity of the printed characters are some examples of challenging document features. In this work, binarization is accomplished by taking advantage of local probabilistic models and of a flexible active contour scheme. More specifically, local linear models are used to estimate both the expected stroke and the background pixel intensities. This information is then used as the main driving force in the propagation of an active contour. In addition, a curvature-based force is used to control the viscosity of the contour and leads to more natural-looking results. The proposed implementation benefits from the level set framework, which is highly successful in other contexts, such as medical image segmentation and road network extraction from satellite images. The validity of the proposed approach is demonstrated on both recent and historical document images of various types and languages. In addition, this method was submitted to the Document Image Binarization Contest (DIBCO??09), at which it placed 3rd. 相似文献
39.
Application of the dry‐spinning method to produce poly(ε‐caprolactone) fibers containing bovine serum albumin laden gelatin nanoparticles 下载免费PDF全文
Bahareh Azimi Parviz Nourpanah Mohammad Rabiee Shahram Arbab Maria Grazia Cascone Andrea Baldassare Luigi Lazzeri 《应用聚合物科学杂志》2016,133(48)
We designed and manufactured a polymeric system with combined hydrophilic–hydrophobic properties by loading gelatin nanoparticles (GNPs) containing bovine serum albumin (BSA) into poly(ε‐caprolactone) (PCL) fibers. Our ultimate goal was to create a device capable of carrying and releasing protein drugs. Such a system could find several biomedical applications, such as those in controlled release systems, surgical sutures, and bioactive scaffolds for tissue engineering. A two‐step desolvation method was used to produce GNPs, whereas PCL fibers were produced by a dry‐spinning method. The morphological, mechanical, and thermal properties of the produced system were investigated, and the distribution of nanoparticles both inside and on the surface of the fibers was examined. The effect of the particles on the biodegradability of the fibers was also evaluated. In vitro preliminary tests were performed to study the release of BSA from nanoparticle‐laden fibers and to compare this with its release from free nanoparticles. Our results indicate that the distribution of particles inside the fibers was quite homogeneous and only a few of them were present on the surface. The presence of the particles in the fibers did not affect the thermal properties of the PCL polymer matrix, although it created voids that affected the degradation characteristics so the PCL fibers favored faster erosion compared to the plain fibers. Preliminary results indicate that the release from GNP‐laden fibers occurred much more slowly compared to that in the free GNPs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44233. 相似文献
40.
Ehteshami-Moinabadi Mohsen Nasiri Shahram 《Bulletin of Engineering Geology and the Environment》2019,78(1):69-88
Bulletin of Engineering Geology and the Environment - The combination of remote sensing observations, geological field investigations and geomorphological mapping and measurements along with faults... 相似文献