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1.
G. Michałek B.R. Bułka 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(1):121-128
The currents and their fluctuations in two capacitively coupled single electron transistors are determined in the limit of
sequential tunnelling. Our considerations are restricted to the case when the islands (dots) of the transistors are atomic-sized,
which means each of them has only one single electronic level available for the tunnelling processes. The Coulomb interactions
of accumulated charges on the both single electron transistors lead to the effect of the negative differential resistance.
An enhancement of the current shot-noise was also found. Spectral decomposition analysis indicated the two main contributions
to the shot-noise: low- and high-frequency fluctuations. It was found that the low frequency fluctuations (polarization noise)
are responsible for a strong enhancement of the current noise.
Received 9 October 2001 / Received in final form 8 March 2002 Published online 9 July 2002 相似文献
2.
西气东输工程中卫黄河穿越隧道长1197.77m,高4.3m,宽5.6m。隧道入口高于黄河水位28m,出口高于黄河水位45m。隧道顶板高程为1130m。位于黄河水下100m。隧道场地围岩为寒武系磨盘井组灰绿色、银灰色浅变质中厚层细粒长石石英砂岩、千枚状板岩、绢云母化千枚岩。围岩为弱风化Ⅲ~Ⅳ类岩石。透水率为4~67Lu,纵波波速为500~3300m.s-1。BQ为300~400。变形模量为6.11~9.22GPa。泊松比(μ)0.14~0.24。内摩擦角(ψ)为42.1°~44.7°。地下水为基岩裂隙水。含水层为寒武系浅变质岩,受大气降水渗入补给,单井涌水量为1.0~50m3.d-1。隧道轴线穿越区岩体较完整—较破碎,未有全新活动断层。隧道位置选择和开挖深度设计是可行的。施工和长期运营是安全的。 相似文献
3.
A suggestion to experimentally measure the electron tunnelling time by observing the tunnelling current cut-off as a function
of the magnetic field intensity in semiconductor pn tunnel junctions, when they are placed in a crossed electric and magnetic
field configuration, has been made in this paper. A simple and a rigorous quantum mechanical analysis to justify the above
proposition have been presented. An order of agreement between the tunnelling time values derived from the published experimental
data and our theoretical prediction has been noticed. 相似文献
4.
W. Medycki 《Phase Transitions》2013,86(9-10):867-872
Spin-lattice relaxation time T 1 is determined for protons in three polycrystals (CH3NH3)5Bi2Cl11, (CD3NH3)5Bi2Cl11 and (CH3ND3)5Bi2Cl11. The temperature dependence of the relaxation times obtained for (CH3NH3)5Bi2Cl11 and (CD3NH3)5Bi2Cl11 are interpreted as a result of correlated motions of the three-proton groups of the monomethylammonium cation. 2H NMR lines of (CD3NH3)3Sb2Br9 have been recorded between 5 K and 291 K using solid echo method. The 2H NMR line shape analysis shows that characteristic shape of tunnelling methyl group appears at about 25 K and coming down with temperature up to 5 K is more distinct. From theoretical calculation, it has been found that in the quadrupolar constants is 161.3 kHz and tunnelling frequency is above 3 MHz. 相似文献
5.
Dongfang Cheng Ziyang Wei Zisheng Zhang Prof. Peter Broekmann Prof. Anastassia N. Alexandrova Prof. Philippe Sautet 《Angewandte Chemie (International ed. in English)》2023,62(20):e202218575
The dynamic restructuring of Cu surfaces in electroreduction conditions is of fundamental interest in electrocatalysis. We decode the structural dynamics of a Cu(111) electrode under reduction conditions by joint first-principles calculations and operando electrochemical scanning tunneling microscopy (ECSTM) experiments. Combining global optimization and grand canonical density functional theory, we unravel the potential- and pH-dependent restructuring of Cu(111) in acidic electrolyte. At reductive potential, Cu(111) is covered by a high density of H atoms and, below a threshold potential, Cu adatoms are formed on the surface in a (4×4) superstructure, a restructuring unfavorable in vacuum. The strong H adsorption is the driving force for the restructuring, itself induced by the electrode potential. On the restructured surface, barriers for hydrogen evolution reaction steps are low. Restructuring in electroreduction conditions creates highly active Cu adatom sites not present on Cu(111). 相似文献
6.
《Physics and Chemistry of Liquids》2012,50(6):559-566
Phillips and Jung [J.C. Phillips and J. Jung (2002). Phil. Mag. B, 82, 1163] refute nodal properties of the gap function Δk and propose an isotropic s-wave picture with electron–phonon interaction as the mechanism for high-T c superconductivity in the cuprates. Here, we compare and contrast predictions of various physical properties with the gap function Δk reflecting three scenarios: (i) isotropic s-wave pairing, (ii) extended s-wave with eight line nodes as championed quite recently by Zhao [G.M. Zhao (2001). Phys. Rev. B, 64, 024503], and (iii) d-wave pairing. By referring to (a) scanning tunnelling microscopy imaging of a Zn impurity, supported by our own subsequent theoretical study, (b) linear decrease of T c with non-magnetic impurity concentration, and (c) calculations on the extended s-wave scenario applied to tunnelling conductance, strong evidence for nodal properties of Δk is given. The contentions of Phillips and Jung [J.C. Phillips and J. Jung (2002). Phil. Mag. B, 82, 1163] should therefore be treated with considerable caution, isotropic s-wave behaviour being truly exceptional among the high-Tc cuprates. 相似文献
7.
A. Di Chiara G. Peluso G. Pepe U. Scotti di Uccio F. C. Matacotta R. Mele E. Olzi 《Il Nuovo Cimento D》1988,10(7):863-867
Summary Preparation procedure and sample characterization of 112 BiSCCO pellets exhibiting high-T
c superconductivity are discussed. TypicalI–V and dV/dI curves of Nb/BiSCCO point conctact junctions at various temperatures are presented. 相似文献
8.
Summary The effect of dissipation in experiments on macroscopic quantum tunnelling in Josephson tunnel junctions are discussed. The
frequency-dependent, nonlinear dynamic resistance of the junction makes it difficult to understand which effective linear
resistance has to be chosen to compare the experimental results with the theory developed in the framework of the RSJ model.
Various experiments reported in the literature lead to different conclusions and are presently discussed. Recently obtained
experimental results on the thermal regime allow us to propose a new experimental strategy which ultimately should remove
any ambiguity on the possibility to observe MQT process in the presence of dissipation in Josephson structures.
To speed up publication, the authors have agreed not to receive proofs which have been supervised by the Scientific Committee. 相似文献
9.
10.
A unique multi-dimensional hybrid system has been developed by incorporating titania nanoparticle into chemically synthesized amorphous carbon nanotubes (a-CNTs)-amorphous graphene composites. The as-synthesized samples were characterized by x-ray diffraction, scanning and transmission electron microscopy; Raman spectroscopy and photoluminescence spectroscopy. The microscopic studies confirm the attachment of the TiO2 nanoparticles on carbon structures. The performance of the both the pure and hybrid samples as cold cathode emitter has been investigated and it has been found that cold emission performance of the pure carbon system improves considerably after TiO2 nanoparticles being added to it giving a turn on field as low as 2.1 V/μm and enhancement factor 2746. The enhancement of field emission characteristic after TiO2 addition was justified from the ‘ANSYS- Maxwell’ software based simulation study. 相似文献