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排序方式: 共有399条查询结果,搜索用时 21 毫秒
101.
Brahim Fady Jaouad Terhzaz Abdelwahed Tribak Fatima Riouch Angel Mediavilla 《国际射频与微波计算机辅助工程杂志》2019,29(11)
This article presents a novel low‐cost integrated multiband antenna design customized for navigation media applications. The distinctive feature of the design consists in using a broadband planar dipole with four arms and a miniaturized feeding‐point, easy to deploy inside the tracking devices, and cost‐effective for supply chain industry. The article first introduces the main challenges and the benefits of miniaturizing antennas for supply‐chain and particularly for navigation media system which is the case‐study. Further the parametric study and final dimensions of the design and the simulation results are discussed. The proposed design is fabricated and the measurements of the radiation pattern and the return loss are performed proving that the antenna with maximum gain up to 10 dBi and S11 up to ?30 dB, exhibits excellent performance for all the frequencies required in the navigation media systems such as 1.6, 1.8, 2.3, 2.4, 2.6, 3.6, and 5.8 GHz. The proposed design was implemented and tested inside a tracking device mounted on a vehicle and compared with existing commercial antennas. This study showed that the proposed antenna is suitable for tracking devices as it is miniaturized for internal integration and it has better 4G and GPS signal detection and low power consumption comparatively with existing commercial antennas. 相似文献
102.
103.
Khurshid Hafiz Fatima Farran Hani Allawnha Mohamad Ayoub Mohammad El‐Chafei 《The International journal of environmental studies》2013,70(4):433-443
Idling the engine of heavy‐duty truck is the only way a driver can control the temperature in the cab/sleeper and have power for auxiliary devices when the truck is parked. It is an inefficient and noisy process that wastes thousands of litres of fuel per year while standing stationary in a parking lot. Almost all heavy‐duty trucks idle about 20–40% of the time when the engine is running, depending on season, geographic location and trucking operation. This extensive engine idling has many disadvantages, including pollutant emissions, noise pollution, unnecessary fuel and maintenance costs, and driver discomfort. This paper discusses the problems related to truck idling and proposes an auxiliary power generation unit that can significantly reduce the fuel consumption, cut the costs, enhance engine life and reduce pollution. A control methodology is presented to regulate the output voltage of the auxiliary power unit under variable load conditions. 相似文献
104.
105.
Kaniz Fatima Sultana So Young Lee Ji-Eun Lee Joobeom Seo Shim Sung Lee 《Inorganic chemistry communications》2007,10(12):1496-1500
Two 20-membered penta- and hexadentate macrocycles containing one or two pyridine subunits, namely [20]aneNO2S2 (L1) and [20]aneN2O2S2 (L2), have been synthesized. Reaction of L1 with silver(I) nitrate afforded a unique 2:2 (M:L) disilver(I) complex [μ2-Ag2(L1)2](NO3)2 (1) in which two four-coordinate Ag atoms bridge two ligands to form a cyclic dimer. In contrast, an endo-dentate 1:1 monosilver(I) complexes [AgL2]X; [X = ClO4 (2) or PF6 (3)] which show isomorphous structures were obtained from the reactions of L2 with silver(I) salts. 相似文献
106.
Yassin Fatima Mohamed Ouarda Wael Alimi Adel M. 《Multimedia Tools and Applications》2022,81(5):6599-6631
Multimedia Tools and Applications - As an increasingly larger number of users partake in Facebook, the images shared and posted by user in Facebook provide a richer background to build a more... 相似文献
107.
108.
Ahmed Naveed Bakar Kamalrulnizam Abu Zuhra Fatima Tul Kehkashan Tanzila Mujahid Muhammad Akram Rathore Muhammad Siraj Dawood Muhammad Isyaku Babangida 《International Journal of Wireless Information Networks》2022,29(3):314-340
International Journal of Wireless Information Networks - Due to fast development in digital systems, the traditional network architecture is becoming inadequate for the requirements of new... 相似文献
109.
We implement and undertake an empirical study of the cache-oblivious variant of the polygon indecomposability testing algorithm of Gao and Lauder, based on a depth-first search (DFS) traversal of the computation tree. According to Abu Salem, the cache-oblivious variant exhibits improved spatial and temporal locality over the original one, and its spatial locality is optimal. Our implementation revolves around eight different variants of the DFS-based algorithm, tailored to assess the trade-offs between computation and memory performance as originally proposed by Abu Salem. We analyse performance sensitively to manipulations of the several parameters comprising the input size. We describe how to construct suitably random families of input that solicit such variations, and how to handle redundancies in vector computations at no asymptotic increase in the work and cache complexities. We report extensively on our experimental results. In all eight variants, the DFS-based variant achieves excellent performance in terms of L1 and L2 cache misses as well as total run time, when compared to the original variant of Gao and Lauder. We also benchmark the DFS variant against the powerful computer algebra system MAGMA, in the context of bivariate polynomial irreducibility testing using polygons. For sufficiently high degree polynomials, MAGMA either runs out of memory or fails to terminate after about 4 h of execution. In contrast, the DFS-based version processes such input using a couple of seconds. Particularly, we report on absolute irreducibility testing of bivariate polynomials of total degree reaching 19,000 in about 2 s for the DFS variant, using a single processor. 相似文献
110.
Fatima Eddoumy Frédéric Addiego Houcine Dhieb Jean‐Pierre Célis René Muller Valérie Toniazzo David Ruch 《Polymer International》2013,62(6):867-877
The impact of processing‐induced chain orientation on the sliding wear behaviour of ultrahigh molecular weight polyethylene (UHMWPE) was investigated. The orientation of the molecular network of UHMWPE was done by means of uniaxial tension up to different residual strains. We found that high residual strain levels (higher than 0.45) enabled the sliding dissipated energy of UHMWPE to be decreased in dry conditions. In particular, oriented UHMWPE with a residual strain of 0.85 exhibited, at 500 000 sliding cycles in dry conditions, a decrease in volumetric wear loss by a factor of 3.3 and 19.4 compared with the reference UHMWPE tested in directions parallel and perpendicular to the chain direction, respectively. It is argued that oriented UHMWPE exhibits less adhesion during interfacial wear than the reference material, and hence orientation of UHMWPE bulk may be an alternative treatment to crosslinking for dry sliding conditions. In the case of sliding testing conducted in Ringer's solution, the benefit of the initial chain orientation was quite weak due to a lubrication effect of the solution that markedly limited the effect of chain orientation on the sliding behaviour. 相似文献