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排序方式: 共有68条查询结果,搜索用时 19 毫秒
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Đurović Gordana Van Neerbos Francine A. C. Bossaert Sofie Herrera-Malaver Beatriz Steensels Jan Arnó Judit Wäckers Felix Sobhy Islam S. Verstrepen Kevin J. Jacquemyn Hans Lievens Bart 《Journal of chemical ecology》2021,47(8-9):788-798
Journal of Chemical Ecology - There is increasing evidence that microorganisms, particularly fungi and bacteria, emit volatile compounds that mediate the foraging behaviour of insects and therefore... 相似文献
3.
Ahmed Hamed Attia Ahmed Sobhy Sherif Ghada Samy El-Tawel 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2016,20(8):3153-3161
Non-symmetric similarity relation-based rough set model (NS-RSM) is viewed as mathematical tool to deal with the analysis of imprecise and uncertain information in incomplete information systems with “?” values. NS-RSM relies on the concept of non-symmetric similarity relation to group equivalent objects and generate knowledge granules that are then used to approximate the target set. However, NS-RSM results in unpromising approximation space when addressing inconsistent data sets that have lots of boundary objects. This is because objects in the same similarity classes are not necessarily similar to each other and may belong to different target classes. To enhance NS-RSM capability, we introduce the maximal limited similarity-based rough set model (MLS-RSM) which describes the maximal collection of indistinguishable objects that are limited tolerance to each other in similarity classes. This allows accurate computation to be done for the approximation space. Furthermore, approximation accuracy comparisons have been conducted among NS-RSM and MLS-RSM. The results demonstrate that MLS-RSM model outperforms NS-RSM and can approximate the target set more efficiently. 相似文献
4.
Sanz-Izquierdo B. Batchelor J.C. Langley R.J. Sobhy M.I. 《Antennas and Propagation, IEEE Transactions on》2006,54(5):1416-1422
A compact multiband planar inverted-F antenna (PIFA) suitable for distributed radio-over-fiber repeater networks is modified into a planar structure. It is shown that the planar antenna performance is not degraded with respect to the original PIFA and further, a two layer design is demonstrated to offer improved feed matching. The European bands for GSM, DCS-1800, DECT, UMTS, Bluetooth and HiperLAN2 are all covered. A model of the antenna is introduced as a first stage to developing an equivalent circuit. 相似文献
5.
Ehab A. Sobhy Ahmed M. Soliman 《International Journal of Circuit Theory and Applications》2010,38(5):441-452
Three novel CMOS realizations for the fully differential voltage second‐generation inverting current conveyor (FDVCCII‐) are proposed in this paper. The first realization has a limited input range, and the other two realizations have a rail to rail input range and show excellent features in linearity and bandwidth. As an application to the FDVCCII‐, a floating gyrator is proposed. A floating inductor is realized using the floating gyrator and it is used in realizing a second‐order low‐pass filter, which is simulated and compared with the ideal result. All circuits are simulated with SPICE using CMOS 0.35µm technology and supply voltages ±1.5V to verify the theoretical results. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
6.
AbstractIn this paper, the effects of hygrothermal conditions on various behaviors, such as bending, free vibration, mechanical and thermal buckling, of exponentially graded microplates lying on two-parameter elastic foundations are investigated. The trigonometric four-variable plate theory incorporated to the modified couple stress theory (MCST) is employed to derive the equations of motion. The present MCST contains an internal material length scale parameter, thus it can capture the size effect. The microplate is assumed to be subjected to a temperature rise and moisture concentration which are varied linearly through the thickness of the plate. Based on an exponential law, the material properties of the microplate are graded only in z direction. The equations of motion are solved analytically to obtain the displacements, stresses, eigenfrequencies and critical buckling load and temperature of the microplates. The present results are validated by comparing them with those previously published. The numerical examples reveal that considering the size effect and/or the elastic foundations leads to an increment in plate stiffness and thereby leads to a decrement in the deflection and an increment in eigenfrequency and buckling loads. It is also shown that the size effect is negligible for the thicker plate. 相似文献
7.
Ahmad Sobhy Helaly 《Egyptian Journal of Petroleum》2019,28(1):77-90
The available aeromagnetic data together with information from some available wells have been used in the current study to shed the light on the geothermal setup of the Nile Delta Province. The aeromagnetic data was reduced-to-pole and critically analyzed using the Spectral Analysis Technique through the Fast Fourier Transform (FFT), to determine the expected depths to the Basement and Curie Point (CPD) surfaces. The geothermal gradient between CPD and earth's surface was estimated, and accordingly the heat flow was evaluated using the proposed thermal conductivity. Then, the Basement Surface Temperature (BST) was estimated, by which the geothermal gradient and heat flow for the igneous-rocky basement and sedimentary-rocky horizon was independently predicted. By which, it could be possible to distinguish between the heat flow contribution from each horizon separately. 相似文献
8.
A Al-Othman S Al-Musharaf NM Al-Daghri S Yakout KM Alkharfy Y Al-Saleh OS Al-Attas MS Alokail O Moharram S Sabico S Kumar GP Chrousos 《Nutrition journal》2012,11(1):56
ABSTRACT: BACKGROUND: Coffee and tea consumption was hypothesized to interact with variants of vitamin D-receptor polymorphisms, but limited evidence exists. Here we determine for the first time whether increased coffee and tea consumption affects circulating levels of 25-hydroxyvitamin D in a cohort of Saudi adolescents. METHODS: A total of 330 randomly selected Saudi adolescents were included. Anthropometrics were recorded and fasting blood samples were analyzed for routine analysis of fasting glucose, lipid levels, calcium, albumin and phosphorous. Frequency of coffee and tea intake was noted. 25-hydroxyvitamin D levels were measured using enzyme-linked immunosorbent assays. RESULTS: Improved lipid profiles were observed in both boys and girls, as demonstrated by increased levels of HDL-cholesterol, even after controlling for age and BMI, among those consuming 9--12 cups of coffee/week. Vitamin D levels were significantly highest among those consuming 9--12 cups of tea/week in all subjects (p-value 0.009) independent of age, gender, BMI, physical activity and sun exposure. CONCLUSION: This study suggests a link between tea consumption and vitamin D levels in a cohort of Saudi adolescents, independent of age, BMI, gender, physical activity and sun exposure. These findings should be confirmed prospectively. 相似文献
9.
M. F. Fahmy M. Abo-Zahhad M. I. Sobhy 《International Journal of Circuit Theory and Applications》1989,17(1):87-101
This paper presents a novel approach for the design and synthesis of odd-degree sampled-data filters. Initially, an efficient iterative scheme is described for the construction of a class of selective linear-phase distributed bandpass filters with equiripple passband loss response. Then, the filter's transfer function is synthesized using classical distributed circuit networks. Finally, the equivalent switched-capacitor filter could be constructed. the resulting switched-capacitor networks are completely insensitive w.r.t. parasitic capacitances, as well as having low Cmax/Cmin Design tables and an illustrative example are also given. 相似文献
10.
The solid-solid interactions between nanosized pure and NiO-substituted ferric and titanium(IV) oxides have been investigated using XRD technique and microstructure studies, also magnetic properties were studied using vibrating samples magnetometer (VSM). The amounts of substituting Ni2+ were x = 0, 0.2, 0.4, 0.6, 0.8 and 1 mole. A mixture equimolar proportions of finely powdered Fe2O3 and TiO2 were mixed with NiO, ball milled, compressed at 250 kg/cm2 and fired at 1200 °C for 4 h.The obtained results showed that with substituting Ni2+ concentration x = 0 only Fe2TiO5 phase is present (∼80 nm) which showed a very small saturation magnetic flux density (Bs), remnant magnetic flux density (Br) and the maximum energy product (BH)max. By the addition of x = 0.2 NiO, new phases were observed NiTiO3 and NiFe2O4 of crystallite sizes 160 and 110 nm, respectively. By the increase of substituting Ni2+ concentration the NiTiO3 and NiFe2O4 phases increased on the expense of Fe2TiO5 up to x = 0.4, then the increase in substituting Ni2+ concentration led to a decrease in Fe2TiO5 and NiTiO3 while NiFe2O4 increases which results in a great improvement of magnetic properties.All samples exhibit a catalytic activity towards H2O2 decomposition and the values of rate constant increase with increasing amount of Ni2+ substituting. The most acidic active sites are shown by specimens substituted with x = 0 this concludes that H2O2 decomposition is not favored on acidic active sites. 相似文献