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21.
Iyad Rahwan Dmytro Krasnoshtan Azim Shariff Jean-Fran?ois Bonnefon 《Journal of the Royal Society Interface》2014,11(93)
Social learning—by observing and copying others—is a highly successful cultural mechanism for adaptation, outperforming individual information acquisition and experience. Here, we investigate social learning in the context of the uniquely human capacity for reflective, analytical reasoning. A hallmark of the human mind is its ability to engage analytical reasoning, and suppress false associative intuitions. Through a set of laboratory-based network experiments, we find that social learning fails to propagate this cognitive strategy. When people make false intuitive conclusions and are exposed to the analytic output of their peers, they recognize and adopt this correct output. But they fail to engage analytical reasoning in similar subsequent tasks. Thus, humans exhibit an ‘unreflective copying bias’, which limits their social learning to the output, rather than the process, of their peers’ reasoning—even when doing so requires minimal effort and no technical skill. In contrast to much recent work on observation-based social learning, which emphasizes the propagation of successful behaviour through copying, our findings identify a limit on the power of social networks in situations that require analytical reasoning. 相似文献
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23.
Chouaib Ennawaoui Houda Lifi Abdelowahed Hajjaji Cdric Samuel Mohamed Rguiti Samira Touhtouh Azeddine Azim Christian Courtois 《Polymer Engineering and Science》2019,59(7):1455-1461
In this article, the authors present a porous copolymer film with pseudo‐piezoelectric effects as a new candidate material for sensing applications. Porous films of poly(ethylene‐co‐vinyl acetate) (EVA) with a thicknesses ranging from 160 to 310 μm are fabricated by a coextrusion chemical foaming process and charged using a high‐voltage contact charging process. Output performances (piezoelectric constant and relative permittivity) with related thermal/mechanical stability are specifically studied as a function of the film porosity and of the electrical charging process. The piezoelectric constant d33 increases with the cell porosity and an interesting piezoelectric constant close to 5.1 pC/N is achieved with a porous EVA film containing 65% of porosity. Actual results are then discussed using a theoretical solid–gas multilayer model to describe and predict the pseudo‐piezoelectric effect of porous polymer materials. The originality of this work lies in the fact that all the steps leading to optimize pseudo piezoelectric films are included, and also in the use of EVA which is not a standard piezoelectric material. Therefore, this work is a contribution in the development of low‐cost piezoelectric materials with potential applications as sensor in different fields such as medical, security, environment, sport, and transport. POLYM. ENG. SCI., 59:1455–1461 2019. © 2019 Society of Plastics Engineers 相似文献
24.
Mahdi Hosseinnejad Abbas Erfanian Mohammad Azim Karami 《International Journal of Circuit Theory and Applications》2019,47(12):2032-2041
In this study, a differential phase-shift-keying (DPSK) demodulator, which is implemented by digital circuit, is proposed. A differential voltage clipper is used to generate narrow pulses at the extremum of the received modulated signal. Regarding the DPSK signal, the outputs of the clipper have double frequency. In order to halve the frequency, a frequency divider is applied to get synchronous clock. Two binary counters are used to detect phase variation; the data are recovered after two times sampling. This technique removes the need for voltage controlled oscillator (VCO). The proposed demodulator is postlayout simulated in a 0.18-μm CMOS process, with a power of 64 μW and active area of 68 × 70 μm2. The demodulator recovers 10 Mb/s data rate at 10-MHz carrier frequency using a 1.8-V power supply. 相似文献
25.
IP header compression schemes offer a valuable measure for bandwidth preservation. Such schemes have been practically implemented in infrastructure‐based IP networks for point‐to‐point links. However, minimal research and practical implementation efforts have been conducted in the direction of an IP header compression strategy that can meet the peculiar requirements of multi‐hop ad hoc wireless networks. In this paper, we present a practically implemented multi‐hop IP header compression scheme using the Robust Header Compression (ROHC) protocol suite. The scheme runs on a novel identifier (ID) based networking architecture, known as an ID‐based ad hoc network (IDHOCNET). IDHOCNET additionally solves a number of bottlenecks of pure IP‐based ad hoc networks that have emerged owing to IP address auto‐configuration service, distributed naming and name resolution, and the role of an IP address as an identifier at the application layer. The proposed scheme was tested on a multi‐hop test bed. The results show that the implemented scheme has better gain and requires only O (1) ROHC contexts. 相似文献
26.
The depolymerization of poly(ethylene terephthalate) (PET) by alcoholysis reaction is an easy operation and gives prospects for the valorization of wastes. PET waste was first depolymerized by glycolysis reaction at different molar ratios of diethylene glycol (DEG), in the presence of Mn acetate as a transesterification catalyst. The glycolyzed products obtained were reacted with p‐hydroxybenzoic acid (PHBA) and maleic anhydride (MA) to prepare modified unsaturated polyesters. The molar ratio of added PHBA was varied in order to investigate its effect on the curing characteristics of these modified unsaturated polyesters. The data obtained revealed that an increasing molar ratio of PHBA, within the studied range of concentrations, leads to a reduction in the peak exothermic temperature (Tmax) accompanied with the required delay in the curing time. The curing characteristics of these modified polyesters are not so fast anymore, which is not manageable and considered as disadvantageous from the practical point of view, showing instead a moderate speed. 相似文献
27.
The current-voltage characteristics of mono-crystalline solar cell device under dark and illumination of 100 mW/m2 (AM1.5) were measured. The efficiency of the studied device under AM1.5 was found to be 14.22%±0.2 compared with the company standards. The capacitance properties of mono-crystalline silicon solar cell device were investigated under dark and illumination conditions. The studied mono-crystalline silicon solar cell exhibits an unusual photocapacitance ranging from 50.4 to 4585 nF under dark and 100 mW/m2 (AM1.5) of white light, respectively. The drastic increase in the capacitance of the solar cell is due to the space charge polarization induced by the increasing number of photogenerated carriers. The photocapacitance mechanism of the solar cell was interpreted by modified Goswami and Goswami (MGG) model. The relative capacitance Cph/Cd (the ratio between the capacitance under illumination to the capacitance under dark) and the relative resistance Rph/Rd (the ratio between the resistance under illumination to the resistance under dark) as a function of the applied frequency at different illuminations were interpreted. The values of the interface state density Nss and interface capacitance Css are increased with the increasing illumination intensities. The prepared mono-silicon solar cell device is a good candidate for photocapacitive and photoresistive sensors in modern electronic and optoelectronic devices. 相似文献
28.
Bronislava Gorr Franz Müller Maria Azim Hans-Jürgen Christ Torsten Müller Hans Chen Alexander Kauffmann Martin Heilmaier 《Oxidation of Metals》2017,88(3-4):339-349
The high-temperature oxidation behavior of a new family of refractory high-entropy alloys (HEAs) with compositions of W–Mo–Cr–Ti–Al, Nb–Mo–Cr–Ti–Al and Ta–Mo–Cr–Ti–Al was studied at 1000 and 1100 °C. Based on these equimolar starting compositions, the main incentive of this study was to select the most promising alloy system whose properties may then be successively improved. Despite the high amount of refractory elements, Ta–Mo–Cr–Ti–Al showed good oxidation resistance at 1000 and 1100 °C. Moderate values of mass gain and complex oxidation kinetics were observed for the W- and Nb-containing HEAs. These alloys formed inhomogeneous oxide scales possessing regions with thick and porous layers as well as areas revealing quite thin oxide scales due to the formation of discontinuous Cr- and Al-rich scales. The most promising behavior was shown by the alloy Ta–Mo–Cr–Ti–Al which followed the parabolic rate law for oxide growth due to the formation of a thin and compact Al-rich layer. 相似文献
29.
Su WS Lekas P Carlisle EJ Cowin R Bellamy J Margetts PJ Brimble KS Clase CM Gangji AS 《Hemodialysis international. International Symposium on Home Hemodialysis》2011,15(2):219-225
Hypophosphatemia is observed in patients undergoing nocturnal hemodialysis. Phosphate is commonly added to the dialysate acid bath, but systematic evaluation of the safety and reliability of this strategy is lacking. The objectives of this study were 4‐fold. First, we determined whether predictable final dialysate phosphate concentrations could be achieved by adding varying amounts of Fleet® enema. Second, we assessed the stability of calcium (Ca) and phosphate dialysate levels under simulated nocturnal hemodialysis conditions. Third, we assessed for Ca‐phosphate precipitate. Finally, we evaluated whether dialysate containing Fleet® enema met the current sterility standards. We added serial aliquots of enema to 4.5 L of dialysate acid concentrate and proportioned the solution on Gambro and Althin/Baxter dialysis machines for up to 8 hours. We measured dialysate phosphate, Ca, pH, and bicarbonate concentrations at baseline, and after simulated dialysis at 4 and 8 hours. We evaluated for precipitation visually and by assessing optical density at 620 nm. We used inoculation of agar to detect bacteria and Pyrotell reaction for endotoxin. For every 30 mL of Fleet® (1.38 mmol/mL of phosphate) enema added, the dialysate phosphate concentration increased by 0.2 mmol/L. There were no significant changes in dialysate phosphate, Ca, pH, and bicarbonate concentrations over 8 hours. No precipitate was observed in the dialysate by optical density measures at 620 nm for additions of up to 90 mL of enema. Bacterial and endotoxin testing met sterility standards. The addition of Fleet® enema to dialysate increases phosphate concentration in a predictable manner, and no safety problems were observed in our in vitro studies. 相似文献
30.
Hamid Reza Armozd Morteza Gharib Hossein Afarideh Mitra Ghergherehchi Azim Ahmadi Niar Morteza Jafarzadeh 《Annals of Nuclear Energy》2011
The radioisotope 16N is produced by the interaction of fast neutrons with 16O in water reactor coolant. This radioisotope emits at the two major gamma ray energies of 6.13 MeV and 7.1 MeV. Exploiting the linear relation between the number of gamma particles versus the reactor power change, the reactor power is determined by detecting and counting the emitted gammas. In this work, for the detection of gammas to measure the reactor power, two different methods are employed. First, by NaI(Tl) scintillator detector and second, by assembly of ten GM detectors. The obtained results confirm that the number of emitted gammas is proportional to the change in reactor power as shown by different monitoring systems such as UIC, CIC, FC, Cherenkov and thermal power. Both of the applied methods are shown to give reliable results for reactor power above 20 kW. Both systems, having been calibrated, are being used as monitoring systems of power in Tehran Research Reactor. These systems are usable in other research reactors and possibly in power reactors as well. 相似文献