A highly simple failure detection method for electrostatic microactuators: application to automatic testing and accelerated lifetime estimation

Reliability and testability are two important factors for the development of batch fabrication of microelectromechanical systems (MEMS) or mixed MEMS/IC applications. In that frame, an easy-to-implement electrical method of detection of failures is presented in this paper, valid for every kind of electrostatic microactuators showing pull-in behavior, with great expectation value in the case of arrayed MEMS. The method relies on the detection of a pull-in current peak at very low frequency. An experimental setup is described and results are shown obtained with prototypes of electrostatic microactuators with parallel capacitances created by deep reactive ion etching on silicon-on-insulator wafers. This method is really suitable for automation and application to on-line testing during mass production and reliability studies. The functional schematic of a test circuitry is proposed for implementation in an industrial tester or for built-in self-test purposes. Then, in order to illustrate the benefits of this method for reliability studies, it is used in conjunction with high voltage testing for accelerated lifetime measurements. A time gain factor of 20 is achieved with above-mentioned test structures.     

Parallel conductance estimation by hypertonic dilution method withconductance catheter: effects of the bolus concentration and temperature

The conductance catheter has gained momentum since its introduction in cardiovascular dynamics back in 1980. However, measuring errors are still blurring its clinical acceptance. The main objective here was to study the effects of the injected saline concentration and temperature on the evaluation of the parallel conductance, Gp, and thus, on the correction volume Vp. That conductance, Gp, and its associated volume, Vp, were computed using 167 saline dilution curves obtained with boluses at different concentrations and temperatures, injected in seven anesthetized closed-chest dogs. The excursion of the total conductance relative to the steady-state value during a saline maneuver showed good correlation with the injected concentration at both studied temperatures. The reference parallel volume (one reference per dog) was defined as the average value obtained with three successive maneuvers, at 6-M concentration and at body temperature; therefore, the method acted as its own reference. The variation of Vp relative to the reference value was clearly dependent on the injected concentration and on its temperature; dispersion was greater at 22 degrees C than at 40 degrees C. The variability would recognize also other causes, such as uncertainty of the extrapolation procedure and the thoracic redistribution of electrical field lines. As conclusion, it is recommended to characterize each maneuver by its concentration and temperature. Body temperature and 6-M concentration appear as the most recommendable combination for the injectate in most animals. Finally, these results intend to characterize the Vp estimation procedure in order to minimize errors. The variability of Vp, in different experimental conditions, demonstrated that both concentration and temperature are additional parameters that may modify the Gp estimate.     

一种改善成像光谱仪光谱检测能力的新方法

为了改善成像光谱仪的检测能力,在不改变硬件结构的情况下,采用光谱细化最优化的新方法,利用液晶可调谐滤光片式成像光谱仪,取得了入射光近似光谱数据,进行了理论分析和实验验证。结果表明,在3组数值仿真数据中,相较于成像光谱仪测量光谱,该方法得到的近似光谱与入射光真实光谱的光谱强度差的标准差分别减小了79.3%,68.3%和58.8%;在两组实验数据中,标准差分别减小了84.4%和60.7%;求解得到的近似光谱与入射光真实光谱的近似程度得到了显著提高,较好地分离了相隔较近的光谱峰。这一研究改善了成像光谱仪的光谱检测能力。     

A novel technique to the solution of transient electromagnetic scattering from thin wires

Previous approaches to the problem of transient scattering by conducting bodies have utilized the well-known marching-on-in-time solution procedures. However, these procedures are very dependent on discretization techniques and in many cases lead to instabilities as time progresses. Moreover, the accuracy of the solution procedure cannot be verified easily and usually there is no error estimation. Recently an alternate approach to the solution of transient scattering by thin wires was presented based on the conjugate gradient (CG) method. In this procedure, space and time are discretized independently into subintervals and the error is minimized iteratively. Unfortunately, this procedure is very slow, not easily extendable to other geometries, and moreover, some of the advantages of marching-on-in-time are lost. In this paper, again the conjugate gradient method is applied to solve the above problem, but this time, reducing the error to a desired value at each time step. Since the error is reduced at each time step, marching-on-in-time can still be done without error accumulation as time progresses. Computationally, this procedure is as fast as conventional marching-on-in-time. Thus, this new method retains all the advantages of marching-on-in-time and yet does not introduce instabilities in the late time. It is also possible to apply this procedure to other geometries. Details of the solution procedure along with numerical results are also presented.     

Evaluation of a novel electrochemical detection method for Chlamydia trachomatis: application for point-of-care diagnostics

Atlas Genetics has developed a point-of-care device for Chlamydia trachomatis utilizing a novel electrochemical detection principle. The assay has a time-to-result of less than 25 min. An independent preclinical validation study using 306 pretyped clinical samples determined a clinical sensitivity of 98.1% and specificity of 98.0%.     

Estimation of the aortic pressure waveform and beat-to-beat relative cardiac output changes from multiple peripheral artery pressure waveforms

We introduce a patient- and time-specific technique to estimate the clinically more relevant aortic pressure (AP) waveform and beat-to-beat relative changes in cardiac output (CO) from multiple peripheral artery pressure (PAP) waveforms distorted by wave reflections. The basic idea of the technique is to first estimate the AP waveform by applying a new multichannel blind system identification method that we have developed (rather than the conventional generalized transfer function) to the PAP waveforms and then estimate the beat-to-beat proportional CO by fitting a Windkessel model to the estimated waveform in which wave distortion should be attenuated. We present an evaluation of the technique with respect to four swine datasets including simultaneous measurements of two peripheral AP waveforms, a reference AP waveform, and reference aortic flow probe CO during diverse hemodynamic interventions. Our results show an overall AP waveform error of 3.5 mmHg and an overall beat-to-beat CO error of 12.9% (after a single CO calibration in each animal). These estimation errors represent substantial improvements compared to those obtained with several alternative PAP waveform analysis techniques. With further successful testing, the new technique may ultimately be employed for automated and less invasive monitoring of central hemodynamics in various cardiovascular patients.     

A simple and novel method for measuring the chirp parameter of anintensity modulated light source

A new and simple method of measuring the chirp parameter α of a modulated light source is presented. The technique involves modulating the optical source in a particular manner, and then directly examining the resulting optical spectrum. This experimental measurement technique allows us to directly measure the phase of the optical signal in the frequency domain. In addition, the method is very easy and accurate. Experimental results demonstrate the use of this measurement technique for measuring the chirp parameter of a source modulated at 10 GHz     

A novel noninvasive measurement technique for analyzing the pressure pulse waveform of the radial artery

Previous noninvasive measurements of the pulse waveform of the radial artery have not employed standard positioning procedures. Here, we propose a new noninvasive measuring apparatus that has a two-axis mechanism and employs a standard positioning procedure for detecting the optimal site for accurately measuring the pressure pulse waveform (PPW). A modified sensor was designed to simultaneously measure the arterial diameter changed waveform (ADCW) and PPW. Considering the artery as a cylinder, the measured waveform would be distorted if the sensor were not at the middle of arterial width. Moreover, a blood vessel is elastic, and its compliance changes with the transmural pressure, being maximal when the transmural pressure is equal to zero. The sensor should detect the PPW with the lowest possible distortion and, hence, an analysis of the vascular geometry and an arterial model were used to design a standard positioning procedure based on the ADCW for the X and Z axes. In order to verify the resolution of the X axis scanning procedure, the echo method was used to measure the radial artery outer diameter in ten healthy subjects. The difference between the scanning width and the actual arterial diameter was 0.36 +/- 0.23 mm (mean +/- SD). Finally, the PPW as measured at the optimal position was used to diagnose myocardial ischemia symptoms in 60 elderly subjects whose chief complaint was chest pain, with the exercise electrocardiogram being used as a reference to compare between individuals with and without myocardial ischemia. The PPW analysis used the harmonic components in the frequency domain. We found that the fourth harmonic of the Fourier series differed significantly between the groups (p = 0.0039), which is consistent with previous studies. The results indicate that our noninvasive measurement apparatus is very suitable for analyzing the PPW of the radial artery.     

A novel nonnegative decomposition method and its application to 2-D digital filter design

In designing two-dimensional (2-D) digital filters in the frequency domain, an efficient technique is to first decompose the given 2-D frequency domain design specifications into one-dimensional (1-D) ones, and then approximate the resulting 1-D magnitude specifications using the well-developed 1-D filter design techniques. Finally, by interconnecting the designed 1-D filters one can obtain a 2-D digital filter. However, since the magnitude responses of digital filters must be nonnegative, it is required that the decomposition of 2-D magnitude specifications result in nonnegative 1-D magnitude specifications. We call such a decomposition the nonnegative decomposition. This paper proposes a nonnegative decomposition method for decomposing the given 2-D magnitude specifications into 1-D ones, and then transforms the problem of designing a 2-D digital filter into that of designing 1-D filters. Consequently, the original problem of designing a 2-D filter is significantly simplified.     

A novel method for the float-point to fixed-point conversion from statistical perspective

The problem of efficient generation of trees of a graph has been treated rather extensively in the literature. In this part of the paper, it is shown that many of the existing techniques can be formulated by matrix algebra. Thus, they can all be unified. The unified theory enables one to summarize many of these results systematically and to provide a simple and easy way for their derivation. The present Part II may be read independently of Part I (see Chen 1969).     

A multistrip moment method technique and its application to thepost problem in a circular waveguide

A moment method technique for solving obstacle problems in a waveguide is presented. Instead of using a multifilament current representation, which leads to a slowly converging series, a multistrip representation of the current is proposed. In the procedure, the matrix elements are determined by a series involving integrals of mode functions over the strips and the convergence is improved. The true currents on obstacle surfaces are replaced by equivalent planar currents in a number of waveguide cross sections inside the obstacle. The technique is applied to a pair of metallic posts in the TE₁₁-mode circular waveguide. Numerical results are compared with experimental data     

A simple quantum-electronic approach to the gyrotron and its application to the solid-state gyrotron

A simple, unifying theory of the gyrotron is presented. It is of the Lamb type. Within its framework, important results from different approaches can he easily obtained. As an application, gyrotron action in InSb is reexamined, and coherent emission at 10¹²Hz appears possible with an output power of about 0.5 mW/mm²of the device.     

A novel method for the detection of apnea and hypopnea events in respiration signals

The monitoring of breathing dynamics is an essential diagnostic tool in various clinical environments, such as sleep diagnostics, intensive care and neonatal monitoring. This paper introduces an innovative signal classification method that is capable of on-line detection of the presence or absence of normal breathing. Four different artificial neural networks are presented for the recognition of three different patterns in the respiration signals (normal breathing, hypopnea, and apnea). Two networks process the normalized respiration signals directly, while another two use sophisticatedly preprocessed signals. The development of the networks was based on training sets from the polysomnographic records of nine different patients. The detection performance of the networks was tested and compared by using up to 8000 untrained breathing patterns from 16 different patients. The networks which classified the preprocessed respiration signals produced an average detection performance of over 90%. In the light of the moderate computational power used, the presented method is not only viable in clinical polysomnographs and respiration monitors, but also in portable devices.     

A novel method for detection of the transition between atrial fibrillation and sinus rhythm

Automatic detection of atrial fibrillation (AF) for AF diagnosis, especially for AF monitoring, is necessarily desirable for clinical therapy. In this study, we proposed a novel method for detection of the transition between AF and sinus rhythm based on RR intervals. First, we obtained the delta RR interval distribution difference curve from the density histogram of delta RR intervals, and then detected its peaks, which represented the AF events. Once an AF event was detected, four successive steps were used to classify its type, and thus, determine the boundary of AF: 1) histogram analysis; 2) standard deviation analysis; 3) numbering aberrant rhythms recognition; and 4) Kolmogorov-Smirnov (K-S) test. A dataset of 24-h Holter ECG recordings (n = 433) and two MIT-BIH databases (MIT-BIH AF database and MIT-BIH normal sinus rhythm (NSR) database) were used for development and evaluation. Using the receiver operating characteristic curves for determining the threshold of the K-S test, we have achieved the highest performance of sensitivity and specificity (SP) (96.1% and 98.1%, respectively) for the MIT-BIH AF database, compared with other previously published algorithms. The SP was 97.9% for the MIT-BIH NSR database.     

A novel detection criterion for weak m-ary signals and its application to ultrawideband multiple access systems

In this paper, we propose a novel criterion for the detection of weak m-ary signals. In the sense of minimizing the error probability, the proposed criterion is optimal when the signal strength approaches zero. Based on the proposed criterion, a detection scheme for ultrawideband multiple access systems is proposed and analyzed in the presence of impulsive interference. Numerical results show that the proposed detector requires less complexity than, and possesses almost the same performance as, the maximum likelihood detector. In impulsive interference, the proposed detector also offers significant performance improvement over the detector optimized for a Gaussian environment.     

基于Rail-GPSAR实测数据的地雷检测新方法

本文借鉴恒虚警率(CFAR)思想估计图像数据中杂波的统计量,实现图像的预白化处理。在训练图像中选取地雷图像切片的距离向中心切线作为本征向量构造训练数据阵,获取检测器的参数估计,结合主分量分析设计高效的偏差最优线性二次(DOLQ)检测器。验证了DOLQ检测器输出的灰度图像服从Gamma分布,利用其分布参数和实测数据特点确定整体阈值。对得到的二元图像利用形态学操作获取可疑目标块,然后通过整体阈值和局部门限确定的自适应阈值对其进行二次检测,以确保无漏检的情况下尽可能降低虚警。基于图像中目标能量的空间范围,提出了利用能量环对预白化处理后的图像进行目标检测。最后,提出了一种将能量环与DOLQ检测器的检测结果进行决策级融合的新方法,完成对不同土壤环境、埋设深度地雷的检测。对实际图像的检测结果表明,新方法能够显著降低虚警,且具有较好的稳健性。     

Ternary mixing: A simple method to tailor the morphology of organic solar cells

We present a detailed study of the effects of ternary mixing on blend morphology, charge carrier mobility and organic solar cell performance. We investigate ternaries consisting of regio random poly(3-hexylthiophene) (P3HT), regio regular P3HT and soluble fullerene derivative, PCBM. By means of absorption, photoluminescence, atomic force microscopy and X-ray diffraction, we demonstrate that the structure of ternary films consists of crystallites of regular P3HT embedded into a random polymer matrix acting as a soft scaffolding where PCBM can only form nanoscale aggregates but cannot grow the detrimental micron-sized structures often observed in the conventional regular P3HT:PCBM case upon annealing. The ternary films exhibit higher degree of crystallinity than the conventional blends, but with smaller crystallite sizes. Moreover, we show that the addition of the random polymer chains does not prevent good charge carrier transport for regio random P3HT concentrations up to 50% of the total polymer content. Finally, we prove that solar cells based on the ternary systems have a similar short circuit current than the conventional binary, but improved open circuit current (by 100 mV), which leads to an overall enhancement of power conversion efficiency.     

A simple method to determine the impedance of a loop antenna

Simple closed formula is given to determine the resistive part of the loop antenna input impedance. An equivalent transmission line is used to determine the reactive part of the input impedance for the same loop, and the antenna in both cases may have any regular configuration. This method has proved to be accurate for a loop perimeter up to0.5 lambdafor the resistive part and up to0.8 lambdafor the reactive part.     

A simple method to determine the floating-body voltage of SOI CMOSdevices

A technique to extract the off-state floating-body (FB) voltage of silicon-on-insulator (SOI) CMOS devices is presented. The bias dependent S-parameter measurements of a single standard FB SOI device and its equivalent circuit, along with the capacitance-voltage (C-V) measurements between the drain and source of the same device, are used to determine the FB voltage. No special test structure design is needed. The technique proposes a method for the extraction of the parasitic source, drain, and gate resistances. Using the technique, FB voltage in excess of 0.4 V is measured in a partially depicted (PD) NMOS device at drain voltage of 2.5 V and zero gate voltage