矿用本安型聚焦双频激电法激电信号接收系统设计

为解决聚焦双频激电法超前探测仪器应用于煤矿井下进行探测的问题,设计了矿用本安型聚焦双频激电法激电信号接收系统.该系统可产生双频PWM驱动控制信号,控制激励信号发送系统产生5路双频调制激励方波电流信号;通过井下测量电极及矿用传输电缆采集微弱激电电压信号,由锁相放大器进行信号处理后获得高低频电压幅值及相位等激电信息;矿用本安型人机界面实现探测数据及图像显示以及对整个系统的控制.研究结果表明:该接收系统产生驱动控制信号的频率为8 Hz及8/13 Hz、4 Hz及4/13 Hz、2 Hz及2/13 Hz、1 Hz及1/13 Hz四组中的任意一组,频率误差绝对值小于0.14%,激电电压幅值测量范围为±5 V,相对测量误差绝对值小于1.4%,满足实际超前探测要求.

矿用双频激电仪接收机微弱信号检测与测试方法

为验证矿用双频激电仪原理样机接收机信号检测的准确性和可靠性,利用互相关检测原理,分析微弱激电信号检测机理,推导激电效应参量数据处理方法,搭建阻容网络试验测试装置,对比模型试验测试与理论计算结果。结果表明:试验测量与理论计算得到的视幅频率值和视相对相位差值随频点变化总体趋势基本一致,但相位测量比幅值测量具有更高的精度,即在幅值测量方面有待于进一步改进和完善。此研究为研制工程样机,开展煤矿井下工业性试验,对适合煤矿井下探测的矿用双频激电法具有重要意义。

煤巷超前探测双频交流激电接收机系统设计

为准确检测煤矿不同地质构造的激发极化信息,针对井下强电磁干扰环境和电器设备使用要求,提出一种适合煤矿井下超前探测的新型双频交流激电接收机。建立以嵌入式单片机为控制中心的硬件系统,研究微弱激电信号检测过程数据处理关键技术,利用C＋＋语言编程完成系统软件设计,实现了激电信息多参量一次性检测,有效保证了微弱激电信号的检测精度。通过阻容模型激电效应试验与分析,观测数据稳定性控制在-1%～1%,视幅频率值最大相对百分比误差不超过0.16%,视相频率值最大相对百分比误差不超过0.08%。

Integrated circuit for single channel neural signal regeneration

Based on the 4-channel neural signal regeneration system which is realized by using discrete devices and successfully used for in-vivo experiments on rats and rabbits, a single channel neural signal regeneration integrated circuit （IC）is designed and realized in CSMC ＇ s 0. 6 μm CMOS （ complementary metal-oxide-semiconductor transistor ） technology. The IC consists of a neural signal detection circuit with an adjustable gain, a buffer, and a function electrical stimulation （FES） circuit. The neural signal regenerating IC occupies a die area of 1.42 mm × 1.34 mm. Under a dual supply voltage of ±2. 5 V, the DC power consumption is less than 10 mW. The on-wafer measurement results are as follows： the output resistor is 118 ml）, the 3 dB bandwidth is greater than 30 kHz, and the gain can be variable from 50 to 90 dB. The circuit is used for in-vivo experiments on the rat＇ s sciatic nerve as well as on the spinal cord with the cuff type electrode array and the twin-needle electrode. The neural signal is successfully regenerated both on a rat＇ s sciatic nerve bundle and on the spinal cord.

The Design and Application of Nerve Stimulator

To apply electrical stimulation to the specific phase position of electroencephalogram （EEG） waveform, a nervous electrical stimulation system was developed using general data acquisition card and LabVIEW virtual instrument environment. The hippocampal field potential signal in the brain of rat was sampled using the acquisition card＇ s A/D channel, and the amplitude and cycle characteristics were analyzed and the wave peak or trough of the coming field potential （ 0 ） rhythm was predicted using LabVIEW program. Meanwhile, the needed stimulus signal was output at the specified phase position via the digital port or D/A channel of the acquisition card, so as to implement the nerve stimulation. The experimental result showed that the prediction accuracies of 0 -rhythm wave peak and trough were up to 92% and 86%, respectively. The electrical stimulation system can be applied to predicting a variety of nervous rhythm wave phases and other signal characteristics because of its universality and flexibility. Thus, a new loop control stimulation method is provided for the nerve electrophysiology study and the electrical stimulation treatment of brain diseases.

A Magnetic Induction Tomography System for Prospective Industrial Processing Applications

Magnetic induction tomography(MIT) is one of the newest industrial process imaging techniques.Main industrial applications of the MIT imaging are in high conductive flow imaging.However,recently it has been shown that the MIT may be useful for low conductive process imaging.This paper presents a cost effective hardware design for MIT in industrial applications,called Bath-MKI industrial MIT system.The system comprises 8 inductor coils and has the possibility of expansion to 16 coils.The excitation signals and the measured voltages are generated and measured using a LabView based system.Two 16 by 1 multiplexers are used to select between the coils.Measurements,excitation and multiplexing are all controlled by a National Instrument(NI) USB based DAQ:USB-6259 and a signal generator.Using the same electronics,the prototype is tested with two different coil arrays;one is a small scale ferrite core coil and one larger scale air cored coil.Experimental image reconstruction results are shown using both small scale and large scale coil arrays.

Sensibility to Changes of Vibrational Modes of Excited Electron： Sum Frequency Signals Versus Difference Frequency Signals

In this paper, we investigate a two electronic level system with vibrational modes coupled to a Brownian oscillator bath. The difference frequency generation （DFG） signals and sum frequency generation （SFG） signals are calculated. It is shown that, for the same model, the SFG signals are more sensitive than the DFG signals to the changes of the vibrational modes of the electronic two-level system. Because the SFG conversion efficiency can be improved by using the time-delay method, the findings in this paper predict that the SFG spectrum may probe the changes of the microstructure more effectively.

Electroacupuncture effect on neurological behavior and tyrosine kinase-JAK2 in rats with focal cerebral ischemia

OBJECTIVE:Electroacupuncture effect on neurological behavior and the expression of tyrosine kinase Janus kinase 2(JAK 2) of ischemic cortex in rats with the focal cerebral ischemia were investigated in this study.METHODS:The model of focal cerebral ischemia was established by the heat-coagulation induced the occlusion of the middle cerebral artery.The electro-acupuncture was applied on Baihui(GV 20) and Dazhui(GV 14),and AG490 was applied by intracerebroventricular infusion.The expressions of JAK2 mRNA and phospharylatedJAK2(p-JAK2) in the ischemic cortex were observed by in situ hybridization and western blotting.RESULTS:The expressions of JAK2 mRNA and p-JAK2 were rarely found in sham surgery group.In model group,the expression of JAK2 mRNA and JAK2 phosphorylation had increased.After 1 day of cerebral ischemia,the expression had reached its peak.After cerebral ischemia,the expressions of JAK2 mRNA and p-JAK2 were consistent with the neurological deficit score.Electroacupuncture treatment and AG490 intervention were able to improve the neurological deficit score after cerebral ischemia,and down-regulate the expressions of JAK2 mRNAand JAK2 phosphorylation.CONCLUSION:After cerebral ischemia,the excessive expressions of JAK2 and the JAK2 phosphorylation would be one of mechanisms by which the brain injury got worse.The therapy of electro-acupuncture could reduce the expression of JAK2,and inhibit JAK2 phosphorylated activation,so as to block the abnormal activation of signal transduction pathway which was induced by JAK2.

Mechanosensation of osteocyte with collagen hillocks and primary cilia under pressure and electric field stimulation

Mechanosensors are the most important organelles for osteocytes to perceive the changes of surrounding mechanical environment.To evaluate the biomechanical effectiveness of collagen hillock,cell process and primary·cilium in lacunar-canalicular system(LCS),we developed pressure-electricity-structure interaction models by using the COMSOL Multiphysics software to characterize the deformation of collagen hillocks-and primary cilium-based mechanosensors in osteocyte under fluid flow and electric field stimulation.And mechanical signals(pore pressure,fluid velocity,stress,deformation)were analyzed in LCS.The effects of changes in the elastic modulus of collagen hillocks,the number and location of cell processes,the length and location of primary cilia on the mechanosensitivity and the overall poroelastic responses of osteocytes were studied.These models predict that the presence of primary cilium and collagen hillocks resulted in significant stress amplifications(one and two orders of magnitude larger than osteocyte body)on the osteocyte.The growth of cell process along the long axis could stimulate osteocyte to a higher level than along the short axis.The Mises stress of the basal body of primary cilia near the top of osteocyte is 8 Pa greater than that near the bottom.However,the presence of collagen hillocks and primary cilium does not affect the mechanical signal of the whole osteocyte body.The established model can be used for studying the mechanism of bone mechanotransduction at the multiscale level.

Artifacts of Functional Electrical Stimulation on Electromyograph

The purpose of this study is to investigate different factors of the artifact in surface electromyography(EMG) signal caused by functional electrical stimulation(FES). The factors investigated include the size of stimulation electrode pads, the amplitude, frequency, and pulse width of the stimulation waveform and the detecting electrode points. We calculate the root mean square(RMS) of EMG signal to analyze the effect of these factors on the M-wave properties. The results indicate that the M-wave mainly depends on the stimulation amplitude and the distribution of detecting electrodes,but not on the other factors. This study can assist the reduction of artifact and the selection of detecting electrode points.