Equivalent circuit modeling of electrokinetically driven analytical microsystems

Equivalent circuit modeling of microfluidic chips accounts for the transport of fluid and electricity in the entire network of microchannels as a function of the applied pressure and electric potentials. For these calculations, each microchannel is represented by a set of conductance coefficients that relates to driving forces and conjugate flows. Theoretical expressions of the coefficients for rectangular microchannels with arbitrary values of the cross-sectional aspect ratio are derived from the fundamentals of electrokinetic phenomena. Particular emphasis is placed on the analysis of the conditions under which the equivalent circuit model can be accurately employed. Model predictions successfully match data on electrokinetically driven chips for immunoassays reported in the literature. A simulation example is also given to illustrate the capability of the technique for the design and manipulation of analytical microsystems.     

H桥式电路驱动无刷直流电机的设计

无刷直流电机是广泛应用于电动汽车、数控机床和家电等领域的重要器件。采用MOS管和专用栅极驱动芯片搭建H桥式驱动电路,主控电路基于ARM微处理器,利用PWM方波通过控制电枢电压的大小占空比从而调节电机速度,以及利用霍尔电流传感器检测电机电流大小监测电机运行情况,从而达到稳定、精细、准确地控制无刷直流电机的正常运行。经实验表明,H桥式电路可以实现无刷直流电机正反运转,并且工作稳定、功耗小、效率高,实现了无刷直流电机稳定可靠软启动和平稳精细调速控制。     

Design of an arithmetic circuit using non-reversible adders in 2 dot 1 electron QCA

Microsystem Technologies - Quantum-dot cellular automata (QCA) appeared as an alternative nanotechnology which is capable of overcoming the shortfalls of the existing CMOS technologies. This energy...     

LiFi cross-connection node model using whispering gallery mode of light in a microring resonator

Microsystem Technologies - A free space cross-connection of the optical signals using an optical micro/nano-electro-mechanical system(OMEMS/ONEMS) is designed and simulated using the commercial...     

SPICE-compatible microwave model of an optically controlled high electron mobility transistor

The effect of optical illumination on the microwave characteristics of an optically gated AlGaAs/GaAs HEMT has been studied theoretically. This article describes an integral approach to the problem which includes the calculation of the capacitance and the sheet concentration of the two-dimensional (2D) electron gas in the illuminated condition. The changes in the various intrinsic parameters of the device under the illuminated condition have been utilized to calculate the Y-parameters of the device at microwave frequencies. The lumped circuit model of the device in the illuminated condition has been obtained with the various components determined from the Y-parameters. The attractive feature of the present model is that it is fully compatible with commonly used circuit simulation packages like SPICE. © 1996 John Wiley & Sons, Inc.     

Evaluation of reservoir sedimentation using data driven techniques

The sedimentation is a pervasive complex hydrological process subjected to each and every reservoir in world at different extent. Hydrographic surveys are considered as most accurate method to determine the total volume occupied by sediment and its distribution pattern in a reservoir. But, these surveys are very cumbersome, time consuming and expensive. This complex sedimentation process can also be simulated through the well calibrated numerical models. However, these models generally are data extensive and require large computational time. Generally, the availability of such data is very scarce. Due to large constraints of these methods and models, in the present study, data driven approaches such as artificial neural networks (ANN), model trees (MT) and genetic programming (GP) have been investigated for the estimation of volume of sediment deposition incorporating the parameters influenced it along with conventional multiple linear regression data driven model. The aforementioned data driven models for the estimation of reservoir sediment deposition were initially developed and applied on Gobindsagar Reservoir. In order to generalise the developed methodology, the developed data driven models were also validated for unseen data of Pong Reservoir. The study depicted that the highly nonlinear models ANN and GP captured the trend of sediment deposition better than piecewise linear MT model, even for smaller length datasets.     

应用Pspice仿真软件优化电路设计

文章对电子电路仿真软件Pspice作了简要介绍,给出了应用实例,实验表明,该软件可以快速、方便、精确地评价电路设计的正确性,并且可以成功地用于电路的优化设计。     

Characteristics of a Pd–oxide–In0.49Ga0.51P high electron mobility transistor (HEMT)-based hydrogen sensor

An interesting hydrogen sensor based on a high electron mobility transistor (HEMT) device with a Pd–oxide–In_0.49Ga_0.51P gate structure is fabricated and demonstrated. The hydrogen sensing characteristics including hydrogen detection sensitivity and transient responses of the studied device under different hydrogen concentrations and temperature are measured and studied. The hydrogen detection sensitivity is related to a change in the contact potential at the Pd/insulator interface. The kinetic and thermodynamic properties of hydrogen adsorption are also studied. Experimentally, good hydrogen detection sensitivities, large magnitude of current variations (3.96 mA in 9970 ppm H₂/air gas at room temperature) and shorter absorption response time (22 s in 9970 ppm H₂/air gas at room temperature) are obtained for a 1.4 μm × 100 μm gate dimension device. Therefore, the studied device provides a promise for high-performance solid-state hydrogen sensor, integrated circuit (IC) and micro electro-mechanical system (MEMS) applications.     

Accurate evaluation of integrals arising from the bulk electron densities in quantum wells of high electron mobility transistors

In this paper we propose a new accurate approach to compute integrals arrays of the electron density and energy density in a multi-layered high electron mobility transistors (HEMTs) device. These new formulas enable the user to calculate efficiently the certain integrals. Example results on the simulation of a certain integrals are given to demonstrate the efficiency of the new scheme. The results are compared with other theoretical calculation results. The convergence rate of the series is estimated and discussed.     

The effect of uniaxial stress on band structure and electron mobility of silicon

The band structure of silicon (Si) under arbitrary stress/strain conditions is calculated using the empirical nonlocal pseudopotential method. The method is discussed with a special focus on the strain induced breaking of crystal symmetry. It is demonstrated that under general stress the relative movement of the sublattices has a prominent effect on the conduction band masses. This displacement, which cannot be determined from macroscopic strain, is extracted from ab initio calculations. The transport properties of strained Si are investigated by solving the semi-classical Boltzmann equation using the Monte Carlo (MC) method. It is shown that the change of the electron effective mass induced by uniaxial stress has to be included in accurate models of the electron mobility.     

Parallel processing circuit of line image using neuristor

A simultaneous detecting circuit system of centers and lengths of some lines in one dimension is presented applying an electronic circuit model of the nervous axon with respect to signal transmission. This model consists of series of one basic section, and has functions of Neuristor. The circuit system has a paralell processing function. It is constructed by three layers. In the first layer each visual signal of lines is changed to electric pulse signal. In the second layer edges of each line are detected, and in the third layer these detected signals are converted into voltages which correspond to lengths of the lines. These functions were confirmed experimentally using its hardware.     

Yield sensitivity study of A1GaAs/GaAs high electron mobility transistor

A simple graphical statistical method is presented and is used to study the statistical sensitivity of the AlGaAs/GaAs High Electron Mobility Transistor (HEMT) small-signal performances to physical model parameters, Using an analytical model and applying numerical techniques, the small-signal performances, transconductance, gate-to-source capacitance, current gain cut-off frequency, and the optimum cut-off frequency are calculated for four different HEMTs. These are then used as the device specifications in the Monte Carlo-based sensitivity analysis. Based on the model, a device simulator is developed in which the gate length, the gate width, and the carrier mobility are statistically varied simultaneously about their nominal values. The yield factor histograms for each small-signal parameter and its sensitivity to the process parameter variations are determined. In this work, we report that the current gain cut-off frequency increases as the carrier mobility increases, but it is almost independent of the gate width. We observe that the gate-to-source capacitance is independent of the carrier mobility, but it is strongly dependent on the transistor dimension. All the performance yields analyzed here go down as the gate length increases.     

利用异步采样电路提高SRAM工艺FPGA的设计安全性

提出了一种利用外接CPLD提高SRAM工艺FPGA设计安全性的方法。该方法利用异步采样电路的不确定性生成随机序列,并且每次上电都产生不同的随机序列,断绝了剽窃者通过克隆序列对系统进行破解的可能性。此外,芯片之间通信采用了M序列加密,以进一步增强系统的安全性。     

基于电路模型的复杂网络节点相似度度量

针对复杂网络中节点相似度度量的问题,在物理学相关知识的启发下,运用相关模型提出了一种基于物理学中电路模型的节点相似度度量的方法.纯粹从节点间的链接图结构来计算节点间的相似度,节点间的相似度用物理学电路模型中的电阻来衡量:电阻越小,相似度越大;电阻越大,相似度越小.实验结果表明了该方法的有效性和合理性,提供了一种借用其它学科方法来解决复杂网络节点相似度度量的新颖方法.     

Coverage enhancement by using the mobility of mobile sensor nodes

Coverage is a fundamental problem in sensor networks. Sensor coverage, which reflects how well a sensor network is monitored by sensors, is an important measure for the quality of service (QoS) that a sensor network can provide. In mobile sensor networks, the mobility of sensor nodes can be utilized to enhance the coverage of the network. Since the movement of sensor nodes will consume much energy, this mobility of sensor nodes should be properly managed by some pre-defined schemes or protocols. By noticing this issue, some existing works have proposed several movement-assisted sensor deployment schemes. These works assume that the target field is a 2-dimensional space. In this paper, we study a generalized case of this problem whereby the target field can be a space which ranges from 1-dimensional to 3-dimensional. Two variations of the movement-assisted sensor deployment problem with different optimization objectives were formulated. We identify a set of basic attributes which can be used as guidelines for designing movement-assisted sensor deployment schemes. Based on these attributes, we propose efficient algorithms for both variants of the movement-assisted sensor deployment problem.     

The mobility of two-dimensional electron gas in AlGaN/GaN heterostructures with varied Al content

The mobility of the two-dimensional electron gas （2DEG） in AIGaN/GaN hetero-structures changes significantly with AI content in the AIGaN barrier layer, while few mechanism analyses focus on it. Theoretical calculation and analysis of the 2DEG mobility in AIGaN/GaN heterostructures with varied AI content are carried out based on the recently reported experimental data. The 2DEG mobility is modeled analytically as the total effects of the scattering mechanisms including acoustic deformation-potential, piezoelectric, polar optic phonon, alloy disorder, interface roughness, dislocation and remote modulation doping scattering. We show that the increase of the 2DEG density, caused by the ascension of the AI content in the barrier layer, is a dominant factor that leads to the changes of the individual scat- tering processes. The change of the 2DEG mobility with AI content are mainly determined by the interface roughness scattering and the alloy disorder scattering at 77 K, and the polar optic phonon scattering and the interface roughness scattering at the room temperature. The calculated function of the interface roughness pa- rameters on the AI content shows that the stress caused AIGaN/GaN interface degradation at higher AI content is an important factor in the limitation of the in- terface roughness scattering on the 2DEG mobility in AIGaN/GaN heterostructures with high AI content.     

Multi-satellite observations on the storm-time enhancements of energetic outer zone electron fluxes driven by chorus waves

The evolution of energetic outer zone electron fluxes during the strong magnetic storm on September 28, 2002 is investigated based on the observations of SAMPEX and GOES-10 satellites. The observations of both satellites showed that energetic electron fluxes increased significantly during the storm recovery phase, and reached the maximum on October 6. The 1.5–14 MeV and 2.5–14 MeV electron fluxes observed by SAMPEX peaked around L=3.5 with values of 6×10 2 cm -2 s -1 sr -1 keV -1 and 5×10 3 cm -2 s -1 sr -1...     

Review on mobility aware MAC protocol using Mobile internet of things

Multimedia Tools and Applications - Modern boom and understanding of our growing needs, applications based on the Mobile Internet of Things (MIoT) are becoming important for future internet...     

Dynamic characteristics of a piezoelectric driven inkjet printhead fabricated using MEMS technology

To understand the residual vibration of the piezoelectric diaphragm in a piezo (PZT) driven inkjet printhead fabricated on silicon wafers by MEMS manufacturing process, the transfer function of the piezo velocity to sinusoidal input voltage is obtained in the experiments. The piezo velocity can be predicted using the obtained velocity transfer function with discrete Fourier transform of a trapezoidal waveform. In the low amplitude of voltage waveform, the spectrum shows a good agreement between the predicted and measured velocities of the piezo diaphragm. However, when the drop is ejected from the nozzle orifice with actual amplitude of the voltage waveform, the spectrum of the piezo velocity shows more complicated frequency components due to the reflected pressure waves and fluid motion inside the chamber. In this study it has been attempted to obtain the transfer function of the piezo velocity to the voltage input when the drops are fired. The simulated results of the piezo displacement with the various durations of the voltage waveform show a good agreement with the drop volume and velocity measured in experiments. In addition, it was found that suppressing the residual oscillations was closely related to eliminating the satellite drop formation, which was confirmed with the strobe stand drop visualization.     

Enhancement of electron mobility in GaAs/AlxGa1-xAs square-parabolic double quantum well HEMT structure

Microsystem Technologies - We show that the enhancement of electron mobility μ as function of well width w can be achieved in a GaAs/AlxGa1-xAs square-parabolic double quantum well (SPDQW)...