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31.
Electrical response of anatase TiO2 films is discussed for different concentrations of CO gas (20-100 ppm) in a nitrogen gas ambient. We investigated temperature (100-300 °C) and film thickness (100-1000 nm) effects for films deposited on glass, sapphire (0 0 0 1) and, Si(1 0 0) substrates. In general, there is a drop in resistance of the device when exposed to CO gas. Films deposited on sapphire showed a larger decrease in the resistance at 300 °C compared to those deposited on glass and silicon substrates. However, films grown on glass and silicon substrates showed a larger decrease in the resistance values for temperature around 200 °C when CO (ppm) values are greater than 40. The change in resistance of the films varies as square root of the CO gas concentration at 200 °C for films deposited on all the three substrates. In general, the decrease in resistance for thicker films is large compared to thinner ones, indicating participation of the bulk in the detection of CO gas. In the presence of O2, film loses its sensitivity to CO gas when the concentration level of O2 approaches 1800 ppm. 相似文献
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Muhammad Mobaidul Islam Abdullah Al Redwan Newaz Li Song Benjamin Lartey Shih-Chun Lin Wei Fan Ali Hajbabaie Mubbashar Altaf Khan Alireza Partovi Tienake Phuapaiboon Abdollah Homaifar Ali Karimoddini 《商业与工业应用随机模型》2023,39(5):684-700
Connected autonomous vehicles (CAVs) have the potential to deal with the steady increase in road traffic while solving transportation related issues such as traffic congestion, pollution, and road safety. Therefore, CAVs are becoming increasingly popular and viewed as the next generation transportation solution. Although modular advancements have been achieved in the development of CAVs, these efforts are not fully integrated to operationalize CAVs in realistic driving scenarios. This paper surveys a wide range of efforts reported in the literature about the CAV developments, summarizes the CAV impacts from a statistical perspective, explores current state of practice in the field of CAVs in terms of autonomy technologies, communication backbone, and computation needs. Furthermore, this paper provides general guidance on how transportation infrastructures need to be prepared in order to effectively operationalize CAVs. The paper also identifies challenges that need to be addressed in near future for effective and reliable adoption of CAVs. 相似文献
34.
Non-resonant microwave absorption (NRMA) studies of superconducting MgB2 and a sample containing ∼10% by weight of MgO in MgB2 are reported. The NRMA results indicate near absence of intergranular weak links in the pure MgB2 sample. A linear temperature dependence of the lower critical field H
c1 is observed indicating a non-s wave superconductivity. However, the phase reversal of the NRMA signal which could suggest d wave symmetry is also not observed. In the MgB2 + MgO sample, much larger low field dependent absorption is observed indicating the presence of intergranular weak links.
The hysteretic behavior of NRMA is compared and contrasted in the two samples. In the pure MgB2 sample, a large hysteresis is observed between the forward and the reverse scans of the magnetic field indicating strong
pinning of flux lines. This hysteresis saturates a few degrees below T
c while in the MgB2 + MgO sample, a much slower increase of hysteresis with decreasing temperature is observed, a signature of weaker pinning. 相似文献
35.
This paper is concerned with an experimental investigation of a comparison of the rheological performance of an ER fluid, consisting of a carrier with a range of solid phase sizes, in oscillatory squeeze-flow under DC conditions. The fluid is sandwiched between two parallel plane electrodes, the upper one stationary and the lower one oscillating normal to its plane. It is seen that the dynamic performance of the fluid, in terms of the capacity for the transmission of imposed forces across the fluid, is highly dependent on the size of the dispersed solid phase and has an optimum value which is dependent on the mean value of the interelectrode gap. In addition the paper includes some measurements of the current through the fluid which may help to shed some further light on the mechanism of the ER effect. Finally the implications of the results to vibration control are discussed. Copyright 1999 Academic Press. 相似文献
36.
Ali Newaz Bahar Radhouane Laajimi Md. Abdullah-Al-Shafi Kawsar Ahmed 《International Journal of Theoretical Physics》2018,57(11):3419-3428
Quantum-dot cellular automata (QCA) is one of the emergent nano-technologies and a potential substitute for transistor based technologies. In this research, an efficient QCA based T, SR and JK flip-flops have been proposed. The proposed gates are implemented with multiplexer, three-input Majority gate and XOR gate. The circuit layouts are designed and verified using QCADesigner version 2.0.3. The simulation result reviles the excellence of the proposed design. The proposed T flip-flop archives 35% improvement in terms cell count. Similarly, the reported RS and JK flip-flop requires 43% and 50% less area respectively in comparison to the previous best single layer design. In addition, QCAPro tool has been used to estimate the power dissipation of all considered designs at different tunneling energy level. 相似文献
37.
Siddiquey IA Furusawa T Sato M Bahadur NM Alam MM Suzuki N 《Ultrasonics sonochemistry》2012,19(4):750-755
In this paper, we report the synthesis of silica coated ZnO nanoparticles by ultrasound irradiation of a mixture of dispersion of ZnO, tetraethoxysilane (TEOS), and ammonia in an ethanol-water solution medium. The silica coating layer formed at the initial TEOS/ZnO loading of 0.8 for 60 min ultrasonic irradiation was uniform and extended up to 3 nm from the ZnO surface as revealed from HR-TEM images. Silica coated ZnO nanoparticles demonstrated a significant inhibition of photocatalytic activity against photodegradation of methylene blue dye in aqueous solution. The effects of silica coating on the UV blocking property of ZnO nanoparticles were also studied. 相似文献
38.
Densities ρ and ultrasonic speeds u of the binary mixtures of tetrahydrofuran (THF) with 1-butanol and tert-butanol, at 30°C, over the entire composition range
were measured. From these data isentropic compressibility, K
s, intermolecular free length L
f, relative association R
A, acoustic impedance Z, molar sound speed R
m, deviations in isentropic compressibility ΔK
s, and excess volume V
E were calculated. The variation of these parameters with composition of the mixture helps us in understanding the nature and
extent of interaction between unlike molecules in the mixtures. Further, theoretical values of ultrasonic speed were evaluated
using theories and empirical relations. The relative merits of these theories and relations were discussed. 相似文献
39.
We study the rheology of semi-dilute solutions of the sodium salt of calf-thymus DNA in the linear and nonlinear regimes.
The frequency response data can be fitted very well to the hybrid model with two dominant relaxation times τ0 and τ1. The ratio (τ0/τ1) ∼5 is seen to be fairly constant on changing the temperature from 20 to 30°C. The shear rate dependence of viscosity can
be fitted to the Carreau model. 相似文献
40.
We have found experimentally that the shot noise of the tunneling current I through an undoped semiconductor superlattice is reduced with respect to the Poissonian noise value 2eI, and that the noise approaches 1/3 of that value in superlattices whose quantum wells are strongly coupled. On the other hand, when the coupling is weak or when a strong electric field is applied to the superlattice, the noise becomes Poissonian. Although our results are qualitatively consistent with existing theories for one-dimensional multibarrier structures, the theories cannot account for the dependence of the noise on superlattice parameters that we have observed. 相似文献