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排序方式: 共有407条查询结果,搜索用时 46 毫秒
1.
2.
Motohiko Kimura Toshifumi Sugiura Yoshihito Fukui Morio Togawa Yukio Harada† 《Artificial organs》1990,14(5):390-391
Carbon fibers with fibrin glue were used as electrodes for diaphragm pacing. The electrodes were applied to three mongrel dogs and the effectiveness was tested. The carbon leads were glued to phrenic nerves by means of the fibrinogen and thrombin bilaterally. The tidal volumes and threshold current level for stimulation were measured at various time up to 9 weeks after implantation. Effective contraction of diaphragm were observed for 9 weeks. By using this electrode, the exfoliation of the nerve is not necessary, the nerve can be maintained in an intact state, and the risk of the implanting operation can be minimized. 相似文献
3.
In some instances the same electrodes are used for stimulation and then for recording a bioelectric event immediately after
the stimulus. However, after the current pulse there remains an electrode potential that decays quasiexponentially. We have
designated this falling potential the electrode-recovery potential. This study investigated the recovery potentials of single
electrodes of rhodium, stainless steel, platinum and platinum-iridium in contact with 0.9% saline at room temperature (25°C)
over a current density ranging from 0.1 to 100 mA/cm2 using a constant-current pulse. In all cases, with increasing current density, there was a decrease in the time for the electrode
potential to fall to one half of the immediate post-stimulus value. Above about 20 mA/cm2 the decrease in recovery time was smooth with increasing current density. Below 20 mA/cm2, the recovery time was slightly irregular. The shortest recovery times were for platinum and platinum-iridium. The largest
decrease in recovery time with increasing current density was for stainless steel, which decreased 10 fold from 0.1 to 100
mA/cm2. The recovery time for rhodium decreased about three-and-one half fold over the same current density range. It was found
that the waveform of the recovery potential is not a simple exponential because the Warburg and Faradic components of the
electrode-electrolyte interface are current-density dependent. In general, for all current densities studied (0.1–100 mA/cm2), there was a sudden initial fall in electrode potential with cessation of current flow, followed by a very gradual nonexponential
decrease in potential. 相似文献
4.
用氟离子选择电极测定牙膏中的氟含量,本法测定回收率为98.63%~104.00%,变异系数为3.83%。 相似文献
5.
K. S. Kohli D. V. Rai P. Kumar V. K. Jindal Dr. N. Goyal 《Medical & biological engineering & computing》1997,35(4):348-353
The complex electrical impedance of a goat eye lens is studied in the frequency range 10mHz−10Hz at room temperature, using
a computer-controlled AC impedance system. AC impedance software (model 368, version 2.2) is employed to determine the total
impedance and capacitance of the eye lens at various frequencies. A Cole-Cole plot of the eye lens material is drawn between
the real component of impedance Z′ and the imaginary component Z″ for each excitation frequency that shows a perfect arc of
a semicircle, with its centre lying below the abscissa at an angle of 35°. The half-angle ϕ between R0 and R∞ is found to be 55°, which mathematically demonstrates the selective permeability of the eye lens. Using graphical analysis
of the Cole-Cole plot, characteristic frequency fc and distribution factor α are observed to be 1Hz and 0.77, respectively. At characteristic frequency, capacitance and total
impedance are found to be 1.14μF and 9.08kΩ. The effect of electrode polarisation on capacitance is corrected, based on Fricke's
power function. The observed electrical parameters are then used to explain the multiple current path through various tissue
compartments. Further, an attempt is made to explain the results on the basis of a possible dipolar model. 相似文献
6.
A glass/silicon composite intracortical electrode array 总被引:5,自引:0,他引:5
Kelly E. Jones Patrick K. Campbell Richard A. Normann 《Annals of biomedical engineering》1992,20(4):423-437
A new manufacturing technique has been developed for creating silicon-based, penetrating electrode arrays intended for implantation
into cerebral cortex. The arrays consist of a 4.2 mm×4.2 mm glass/silicon composite base, from which project 100 silicon needle-type
electrodes in a 10×10 array. Each needle is approximately 1,500 μm long, 80μm in diameter at the base, and tapers to a sharp
point at the metalized tip. The technique used to manufacture these arrays differs from our previous method in that a glass
dielectric, rather than ap-n-p junction, provides electrical isolation between the individual electrodes in the array. The new electrode arrays exhibit
superior electrical properties to those described previously. We have measured interelectrode impedances of at least 1013 Ω, and interelectrode capacitances of approximately 50 fF for the new arrays. In this paper, we describe the manufacturing
techniques used to create the arrays, focusing on the dielectric isolation technique, and discuss the electrical and mechanical
characteristics of these arrays. 相似文献
7.
M. D. Craggs N. de N. Donaldson P. E. K. Donaldson 《Medical & biological engineering & computing》1986,24(4):424-430
The paper introduces the electrode limit-voltage plane (ELVP)—a useful tool for describing in electrical terms what a polarisable
electrode is doing under a particular set of conditions. The ELVP is then used to consider the charge-injection capability
of a platinum stimulating electrode. 相似文献
8.
外层型视网膜假体采用了MEMS技术,通过植入到视网膜相应部位的电极来刺激神经节细胞,并且能够在大脑皮层视觉区域引起对应的特征电位反应,最终部分恢复生物体的视觉.这种外层型视网膜植入装置可分为眼外和眼内部分.后者功能相对重要,设计也较为复杂.它是由包含MPDA和微电极的刺激芯片及附属装置组成.本篇文章主体包括四部分:首先是视网膜假体的概况;其次是视网膜生理基础和视网膜假体理论的简介;在第三部分,为设计理念和MPDA的制造过程;最后,是对难题的讨论和未来发展的展望. 相似文献
9.
P. Zipp 《European journal of applied physiology》1982,50(1):41-54
Summary Standardized lead positions for recording myoelectric signals are given for various muscles. The positions are given in terms of (1) the lead line connecting two anatomical landmarks and (2) the central lead point about which the electrodes are placed symmetrically on the lead line.This research was financially supported by the Sonderforschungsbereich 152 of the Deutsche Forschungsgemeinschaft 相似文献
10.
The series equivalent resistance R and capacitance C of metal/saline electrode/electrolyte interfaces were measured as a function
of frequency (100 Hz–20k Hz) and current density (0·25 to 1000 A m−2) for eight typical electrode metals. For each of the metals tested, R decreased and C increased as the current density was
increased above a critical value (with the exception of silver and MP35N at frequencies above 1 kHz for which R increased
and C decreased slightly). With the exception of copper, the current density linearity limit (for 10 per cent decrease in
R or 10 per cent increase in C) increased with increasing frequency and, in most cases, the current density linearity limit
for 10 per cent increase in C was slightly less than that for 10 per cent decrease in R. Among the metals tested, copper and
aluminium had the lowest current carrying capability and rhodium had the highest current-carrying capability. The current
carrying capabilities of 316 SS, platinum, silver and MP35N, were intermediate and similar. With increasing current density,
an increase in the electrode/electrolyte capacitance was the most sensitive indicator of the current-carrying linearity limit. 相似文献