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1.
Formation of nanogaps in electrochemically deposited films of metals by the stress relaxation method
Formation of a set of planar electrodes spaced about 10 nm apart by electrochemical “healing” of gaps 50 to 100 nm wide in
half-finished electrodes is described. The method consists in complete healing of the gap followed by the creation of a discontinuity
at the joint of the electrodes via relaxation of stresses arising in the course of film deposition. 相似文献
2.
Gap detection thresholds were measured as an indication of the amount of interaction between electrodes in a cochlear implant. The hypothesis in this study was as follows: when the two stimuli that bound the gap stimulate the same electrode, and thus the same neural population, the gap detection threshold will be short. As two stimuli are presented to two electrodes that are more widely separated, the amount of neural overlap of the two stimuli decreases, the stimuli sound more dissimilar, and the gap thresholds increase. Gap detection thresholds can thus be used to infer the amount of overlap in neural populations stimulated by two electrodes. Three users of the Nucleus cochlear implant participated in this study. Gap detection thresholds were measured as a function of the distance between the two electrode pairs and as a function of the spacing between the two electrodes of a bipolar pair (i.e., using different modes of stimulation). The results indicate that measuring gap detection thresholds may provide an estimate of the amount of electrode interaction. Gap detection thresholds were a function of the physical separation of the electrode pairs used for the two stimuli that bound the gap. Lower gap thresholds were observed when the two electrode pairs were closely spaced, and gap thresholds increased as the separation increased, resulting in a "psychophysical tuning curve" as a function of electrode separation. The sharpness of tuning varied across subjects, and for the three subjects in this study, the tuning was generally sharper for the subjects with better speech recognition. The data also indicate that increasing the separation between active and reference electrodes has limited effect on spatial selectivity (or tuning) as measured perceptually. 相似文献
3.
The behavior of the impedance spectra of island permalloy films prepared through vacuum evaporation onto optically polished
glass-ceramic substrates has been investigated in the frequency range from 0.0001 to 100 MHz. A resistor-capacitor model of
the films has been developed and the model parameters, for which there is a good agreement with experimental data on the frequency
dependences of the real and imaginary components of the impedance, have been determined. The specific features in the behavior
of the electrical and physical characteristics with variations in the thickness of the sample and the gap between the measuring
electrodes have been investigated. It has been found that the relative permittivity of the films under investigation reaches
values ɛ ∼ 107–108. The structural relaxation times have been calculated. 相似文献
4.
Zhuoyu Ji Hongxiang Li Yaling Liu Wenping Hu 《Applied Physics A: Materials Science & Processing》2008,91(2):301-303
In this paper we propose a method for the integration of the synthesis of silver-tetracyanoquinodimethane (AgTCNQ) and the
fabrication of its devices within one step. The method was performed by electroplating Ag between gold coplanar micro-gap
electrodes in tetracyanoquinodimethane (TCNQ) solution. As soon as silver was electrochemically dissolved in the TCNQ solution,
it immediately reacted with TCNQ to form AgTCNQ and then deposited between Au gap electrodes. With the continuing of the reaction,
the Au micro-gap electrodes were connected by AgTCNQ to form Au/AgTCNQ/Au coplanar gap devices. With this electroplating technique,
series gap devices of AgTCNQ were fabricated, and the devices exhibited switching phenomena with good reproducibility. This
method integrated the synthesis of AgTCNQ and the fabrication of its devices within a single step, and should be also inspirable
for other charge transfer complexes.
PACS 81.05.Hd; 81.20.Ka; 82.45.Aa; 82.45.Qr 相似文献
5.
The influence of phosphate glass electrode in the configuration of resistive plate chamber has been studied using GEANT3.21
Monte Carlo code. Bakelite electrodes were replaced by phosphate glass electrodes, as these glass materials have low bulk
resistivity, are portable and easy to handle. These types of RPCs in their compact form of all materials are suitable for
high rate background environment. We find that these new types of RPCs give little higher response to γ-rays and e+/e− particles, both for single-and double gap RPCs. The results of simulation are discussed.
相似文献
6.
The process of electroforming (the production of a carboniferous conducting medium when the current flows through an organic
material under a high electric field) in open sandwichlike structures with an insulating gap several tens of nanometers in
width is considered. It is shown experimentally that there are factors that both favor (external ballast resistor) and prevent
(local spreading resistance and the presence of the initial conductivity in the insulating gap) the production of a single
conducting element between the electrodes. A simple model of the process in terms of the equivalent electric circuit is proposed.
The model helps to find the trade-off between these factors and to construct an I-V diagram, which exhibits a region within which a single conducting nanostructure can be electroformed. An expression that
relates the minimum permissible resistance of the nanostructure to its geometric parameters is derived. 相似文献
7.
N. R. Aghamalyan R. K. Hovsepyan I. A. Gambaryan E. A. Kafadaryan S. I. Petrosyan G. R. Badalyan A. K. Shirinyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2010,45(1):33-41
Transparent and conducting pure and Ga-doped ZnO films prepared by e-beam evaporation in vacuum were irradiated at room temperature
by Co60 radiation source with the γ-photon average energy of 1.25 MeV and with different doses up to ∼600 kGy. The energy band gap
E
g, electrical resistivity, carrier density as well as the structure parameters of pure and doped ZnO films versus the impurity
content and γ-doses were determined in order to estimate the radiation-induced degradation effect on ZnO-based films used
as transparent electrodes for electro-optical device applications. 相似文献
8.
A. M. Boichenko 《Technical Physics》2011,56(3):317-321
The mechanism of production of electrons with an “anomalous” energy in the spectrum of high-power nanosecond electron bunches
is investigated. Spherically symmetric propagation of the bunch between spherical electrodes in vacuum diodes with a large
potential difference is considered. The results are compared with the earlier results on 1D propagation of the bunch between
spherical electrodes. 相似文献
9.
The observation of the asymmetric passage of current in a plasma interrupter under certain conditions is reported. The effect
can be attributed to different temperatures of the electrodes for the laser production of plasma in the interrupter.
Zh. Tekh. Fiz. 69, 77–79 (March 1999) 相似文献
10.
Fabrication of a carbon nanotube device using a patterned electrode and a local electric field 总被引:1,自引:0,他引:1
Fujio Wakaya Jun Takaoka Kiyofumi Fukuzumi Mikio Takai Yoichi Akasaka Kenji Gamo 《Superlattices and Microstructures》2003,34(3-6):401
Suspensions of carbon nanotubes (CNTs) and organic solvent were dropped onto a substrate which had patterned electrodes while applying a DC voltage between the electrodes. Both multiwall and single-wall (SW) CNTs were purified from the mixture of CNTs and the undesirable particles of carbon when the solvent dichloromethane was used at high temperature. It is found that a SW CNT bridges the gap of the electrodes. This enables us to fabricate CNT devices at a controlled position. 相似文献
11.
D. Sahu S. Bhattacharjee M. Bandyopadhyay A. K. Chakraborty 《Indian Journal of Physics》2011,85(12):1871-1878
A microwave driven multicusp plasma based volume negative ion source equipped with a magnetic filter is developed. Instead
of employing any electrodes or current carrying filaments, microwaves of frequency 2.45 GHz is used to generate plasma by
resonance heating mechanisms namely the electron cyclotron resonance (ECR) and upper hybrid resonances (UHR), occurring near
the boundary plasma layers. The principal process of negative ion production in hydrogen is dissociative attachment of low
energy (0.5–1.0 eV) electrons to vibrationally excited neutral molecules generated from high energy (15–20 eV) electron impact.
The source therefore necessitates two distinct spatial regions (a) production and (b) attachment chambers; which would contain
electrons with optimum cross section for the aforementioned processes. A biased grid after the magnetic filter further helps
to lower down the electron temperature to ≤1 eV which is favorable for the dissociative attachment process. 相似文献
12.
This paper reports on the results of the investigation of the high-frequency susceptibility of a layered ferromagnetic structure
in which, apart from a periodic change in the magnetic anisotropy parameter from layer to layer, this parameter varies along
layers according to a random law (the superlattice with two-dimensional phase inhomogeneities). The evolution of the frequency
dependence of the imaginary part of the averaged Green’s function in the range of the energy gap (band gap) in the spectrum
of waves propagating along the superlattice axis due to the change in the relative root-mean-square fluctuations of the phase
γ2 has been studied at the boundaries of the odd Brillouin zones. It has been found that, for all odd Brillouin zones, the
imaginary part of the Green’s function exhibits a universal behavior: the peak corresponding to the edge of the band gap with
a lower frequency remains unchanged, and the peak corresponding to the edge of the band gap with a higher frequency is smoothed
with an increase in the quantity γ2. These effects, which were initially revealed at the boundary of the first Brillouin zone of the sinusoidal superlattice,
have been explained, as before, by the specific features of the energy conservation laws for the incident and scattered waves
in the lattice with two-dimensional inhomogeneities. It has been demonstrated that an increase in the Brillouin zone number
leads to a decrease in the value of γ2 at which the peak at the edge of the band gap with a higher frequency disappears. 相似文献
13.
J. Mahoney W. Zhu V. S. Johnson K. H. Becker J. L. Lopez 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(3):441-447
We report a capillary dielectric barrier discharge (Cap-DBD) plasma operated in atmospheric pressure air. The plasma reactor
consists of metal wire electrodes inside quartz capillary tubes powered with a low kilohertz frequency AC high voltage power
supply. Various reactor geometries (planar, 3-D multilayer, and circular) with wall-to-wall separation ranging from zero up
to 500 micron were investigated. For the electrical and spectral measurements, three reactors, each with six tubes, six inches
in length, were assembled with gap widths of 500 micron, 225 micron, and 0 micron (i.e. tubes touching). The discharges appear
homogenous across the whole device at separations below 225 micron and turned into filamentary discharges at larger gap spaces.
The operating voltage was generally around 3–4 kV (rms). The power consumption by the Cap-DBD was calculated using voltage/charge
Lissajous figures with observed powers of a few watts to a maximum of about 14 W for the reactor with no gap spacing. Further
studies of optical emission spectroscopy (OES) were employed to evaluate the reactive species generated in the microplasma
source. The observed emission spectrum was predominantly within the second positive system of
N2\mbox{N}_2(C3\mbox{C}^3
Pu\Pi_u–B3\mbox{B}^3
Pg\Pi_g) and the first negative system of
N+2\mbox{N}^+_2(B2\mbox{B}^2
S+u\Sigma^+_u–X2\mbox{X}^2
S+g\Sigma^+_g). 相似文献
14.
研制了一种适用于平行板传输连接的平面火花隙三电极开关,开关正负电极为半圆形状,触发电极为细条状。将之替代立体式(半球形电极)火花隙三电极开关并应用于爆炸箔起爆装置中,装置回路参数将得以优化。实验测试了空气间隙为4.12, 3.14和2.2 mm的平面火花隙三电极开关的性能。结果表明,在开关间隙间距一定的情况下,随着电压的升高,开关间隙的放电时延和分散时间呈指数降低,开关电感小于15 nH;对于不同范围内的应用电压,使用不同间隙间距的开关,其分散时间不大于10 ns。该开关应用于较低充电电压(小于10 kV)的脉冲功率装置中,与立体式火花隙三电极开关相比,回路电感降低了约50 nH,放电周期缩短近1/3,峰值电流增加约1/3。 相似文献
15.
A. S. An’shakov I. M. Ulanov E. K. Urbakh A. E. Urbakh V. A. Faleev 《Thermophysics and Aeromechanics》2007,14(3):439-443
The AC plasma electric furnace with graphite electrodes was tested using methane as the modelling gas. Its advantage for production
of hydrogen and fine soot was demonstrated. It was found that 1150–1200 °C of the reactor wall is enough for complete methane
decomposition. It was shown that specific erosion of graphite electrodes is about 5·10−9 kg/C at the average current density of 32 A/cm2.
The work was financially supported by the State Contract No. 02.515.11.5010 (March 6, 2007). 相似文献
16.
Finger capacitance of a terahertz photomixer in low-temperature-grown GaAs using the finite element method
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Interdigitated finger capacitance of a continuous-wave terahertz photomixer is calculated using the finite element method.For the frequently used electrode width(0.2 μm) and gap width(1.8 μm),the finger capacitance increases quasi-quadratically with the number of electrodes increasing.The quasi-quadratic dependence can be explained by a sequence of lumped capacitors connected in parallel.For a photomixer composed of 10 electrodes and 9 photoconductive gaps,the finger capacitance increases as the gap width increases at a small electrode width,and follows the reverse trend at a large electrode width.For a constant electrode width,the finger capacitance first decreases and then slightly increases as the gap broadens until the smallest finger capacitance is formed.We also investigate the finger capacitances at different electrode and gap configurations with the 8 μm× 8 μm photomixer commonly used in previous studies.These calculations lead to a better understanding of the finger capacitance affected by the finger parameters,and should lead to terahertz photomixer optimization. 相似文献
17.
The chemical interactions and physical processes occurring in a high energy spark gap with different combinations of gases, electrodes, and insulators were studied. The electrodes studied were graphite and a tungsten-copper composite; the insulators were Lexan and Blue Nylon; and the gases were N2 and SF6. The gas composition was monitored with a mass spectrometer. Spectroscopic techniques were used to observe the arc channel. The electrode surfaces were studied with several surface analysis techniques, including scanning electron microscopy, electron spectroscopy for chemical analysis, Auger electron spectroscopy, and X-ray fluorescence. The breakdown voltage distribution was examined for different material combinations. The plasma chemistry processes involving the gas, electrode, and insulator materials were found to affect the voltage self-breakdown distribution. The detailed surface analysis gave information about the nature of the chemical processes. The presence of Blue Nylon seemed to have a more adverse effect than Lexan and graphite seemed to have a narrower voltage distribution than the tungsten-copper composite. 相似文献
18.
研制了一种适用于平行板传输连接的平面火花隙三电极开关,开关正负电极为半圆形状,触发电极为细条状。将之替代立体式(半球形电极)火花隙三电极开关并应用于爆炸箔起爆装置中,装置回路参数将得以优化。实验测试了空气间隙为4.12, 3.14和2.2 mm的平面火花隙三电极开关的性能。结果表明,在开关间隙间距一定的情况下,随着电压的升高,开关间隙的放电时延和分散时间呈指数降低,开关电感小于15 nH;对于不同范围内的应用电压,使用不同间隙间距的开关,其分散时间不大于10 ns。该开关应用于较低充电电压(小于10 kV)的脉冲功率装置中,与立体式火花隙三电极开关相比,回路电感降低了约50 nH,放电周期缩短近1/3,峰值电流增加约1/3。 相似文献
19.
The results of experimental investigation of the stability boundary for a spatially homogeneous state of a discharge in the
planar gap of a “semiconductor-gas-discharge” cryogenic system filled with nitrogen are considered. The semiconductor cathode
was prepared from single-crystalline silicon doped with a deep-lying impurity. Quantitative data are obtained for the conditions
of formation of a hexagonal dissipative structure in the current distribution for two values of the discharge gap length upon
a change in the gas pressure and in the conductivity of the cathode. It is found that for a fixed gap length, the formation
of the critical state can be described approximately by a universal function of the electrode conductivity and gas pressure. 相似文献
20.
É. N. Voronkov 《JETP Letters》1999,70(2):72-74
The results of an experiment demonstrating the appearance of a soliton under certain conditions of pulsed breakdown of a glassy
semiconductor film in a magnetic field are reported. The wave is excited by a current filament moving at a velocity close
to the speed of sound between two parallel electrodes in an external magnetic field. To distinguish the direction of motion
of the acoustic wave and that of the current filament along the substrate, electrodes with a bend that changes the direction
of motion of the filament are deposited. Two “frozen” structural-excitation fronts, diverging at an angle to one another and
attesting to the decay of the soliton at the moment the current filament vanishes, are observed at the location of the bend
in the electrodes.
Pis’ma Zh. éksp. Teor. Fiz. 70, No. 2, 70–72 (25 July 1999) 相似文献