SEPARATION OF OVERLAPPING INCISIONS OF A.C.OSCILLOPOLAROGRAM USING KALMAN'S FILTER TECHNIQUE

Kalman's Filter Technique for the separation of overlapping incisions of an a.c.oscillopolarogram is presented,the experimental verifications were carried out in various systems with the ions of Pb^(2+),Tl^+,In^(3+)and Cd^(2+).The results showed that the concentration of the depolarizer can be determined directly and easily with this technique in the presence of interference elements.

Tunable wavelength filters using polymer long-period waveguide gratings based on metal-cladding directly defined technique

In this work, long-period waveguide grating-based tunable wavelength filters using organic–inorganic grafting poly（methyl methacrylate）（PMMA） materials are designed and fabricated by metal-cladding directly defined technique.The thermal stabilities and optical properties of the organic–inorganic grafting PMMA core materials are analyzed. Structures and performance parameters of the waveguide gratings and self-electrode heaters are designed and simulated. The contrast of the filter is about 15 d B and the resonant wavelength can be tuned by different electric powers applied to the metal-cladding self-electrode heaters. The temperature sensitivity is 3.5 nm/℃ and the switching time is about 1 ms. The technique is very suitable for realizing the optoelectronic integrated wavelength-division-multiplexing systems.

A Low Phase Noise, Low Power and Wide Tuning Range VCO with Filtering Technique in ISM Band

In this paper, a novel voltage controlled oscillator (VCO) with low phase noise, low power consumption and wide tuning range in the industrial, scientific and medical (ISM) band is proposed for communication systems applications. For improving the phase noise, filtering technique is used and VCO is designed with TSMC CMOS 0.18 μm technology and the power supply is 1.5 V. The simulation results with advanced design system (ADS) shows that phase noise in 1 MHz offset frequency from the carrier is -122 dBc/Hz and tuning range is 2 to 2.8 GHz. The power consumption of the core is 2.49 mW.

The Developmentand Clinical Application of Acoustical Technique in Hip Joint

A non- invasive acoustical system was developed for the measurement of transmission properties of acoustic waves in the hip joints.The instrumentation consisted of three sub- system s. An excitation system employed a vibratory force at the sacrum of the test subjects.A transduction system included a pair of identical microphones installed in the tubes of two stethoscopes,which were placed at the greater trochanters on both sides for picking up the acoustical signals transm it- ted across the hip joints.The data acquisition and analysis system was a portable signal analyzer with a program of dual channel digital filter for m easuring the power of acoustical signal in 1/ 3- oc- tave frequency bands.2 7normal adults,2 0 normal pre- school children and 4 0 norm al neonates were random ly selected for testing.Coherence function (CF) and discrepancy(D) was measured during the testing.Results from the three groups showed that there was a high coherence of the signals (CF>0 .9) and a sm all discrepancy(D<3d B) between bilateral hips in the frequency range of2 0 0— 315 Hz.For normal neonates,there was a wider frequency range of16 0 - 315 Hz in which the acoustical signals m aintained a high coherence (CF>0 .93) and a smaller discrepancy (D <2 d B) was observed.This study showed that the development of the acoustical technique pro- vided a practical m ethod with objective parameters.The results obtained in this study can offer a baseline for further investigation of hip disorders particularly those related to structural abnorm ali- ties of the hip.

Analysis of μ-Czochralski Technique Using Two-Dimensional Crystallization Simulator

μ-Czochralski technique has been analyzed using two-dimensional crystallization simulator. It is observed that the temperature is relatively uniform in the entire Si region after the laser irradiation because the heat conductivity of the Si region is much higher than that of the underneath SiO2. Grain growth advances from the grain filter to the channel region and continues until it collides with what advances from random nucleation in the channel region. When the initial temperature is high, the random nucleation rarely occurs even under the supercooling condition, and the grain size becomes large. Moreover, it is qualitatively reproduced that the grain size increases as the irradiated energy of the laser irradiation increases.

基于阶梯阻抗谐振器的双频宽带滤波功分器

为了更好地满足无线通信系统对多功能、多频段射频前端器件的要求,提出了一种基于阶梯阻抗谐振器的双频宽带滤波功率分配器。首先,使用单个T形谐振器实现双频滤波单元,同时采用阶梯阻抗技术引入了单独可调的高次模用于展宽双频功分器的高频通带带宽;其次,利用枝节加载技术实现额外谐振模式的引入,展宽了双频滤波功分器低频通带带宽;为了实现小型化设计,对部分微带线进行弯折,使得整个电路结构更加紧凑。此外,利用T形谐振器自身的滤波特性和在微带馈线上加载的开路枝节,在带外产生四个可控的传输零点,提高了通带外选择性;通过在微带馈线上加载扇形枝节和在输出端口引入隔离电阻,有效改善了滤波功分器的带内阻抗匹配效果和隔离度。为了进一步验证,对所提出的滤波功分器进行了加工和测试。该滤波功分器的中心频率为2.83 GHz和4.87 GHz,相对带宽分别为10.6%和11.7%,通带隔离度均大于14.5 dB。测试和仿真结果基本一致。

2008年M_(W)7.9汶川地震早期余震频度衰减速率空间分布特征分析

深入认识余震频度衰减及其影响因素对理解余震触发机理和震后应急救援具有重要意义.然而,由于强震后余震数量庞大,波形相互叠加导致了目录中余震缺失,进而影响了余震频度衰减速率的估计.本研究采用模板匹配技术对2008年M_(W)7.9汶川地震后约50天内连续数据进行扫描,检测余震数量约为模板地震数量的5倍,完备震级由M3.0降低到M2.3.根据余震沿映秀—北川断裂走向优势深度分布的变化,以映秀、汶川、茂县、北川、南坝为界,余震活动大致可分为6个区域.本研究利用最大似然法分别计算了各个区域的余震频度衰减速率,结果显示:以茂县、青川为界,余震频度衰减速率表现出映秀—北川断裂西南段较快、中间段居中、东北段较慢的特征.将余震频度衰减速率和余震空间分布、断裂类型、震后形变、同震形变等进行对比分析,本研究得到以下结论:1、余震频度衰减速率分区与断裂类型分区吻合.其中,映秀—北川断裂西南段余震频度较快衰减速率区域断裂以逆冲为主,中间段为经过各种震源机制类型交替出现的过渡带,映秀—北川断裂东北段余震频度较慢衰减速率区域断裂以右旋走滑为主;2、余震频度衰减速率西南段较快、东北段较慢的空间分布特征与震后形变特征相一致;3、余震频度衰减速率与同震形变相关性不强.结合本研究观测到的同震滑移量较大区域余震分布较少、部分区域余震数目和震后形变空间分布一致性等特征,我们推测汶川地震早期余震可能主要与震后余滑相关,余震频度衰减速率的空间分布差异主要与不同类型断裂震间滑移速率不同相关,震间滑移速率较快的区域余震频度衰减速率较快及震后形变较大.

基于改进群稀疏正则化的稀疏角度图像重建

计算机断层扫描(Computer Tomography,CT)是临床医学中广泛使用的医学图像,可以清楚地显示人体的精细结构细节,为医生诊断疾病提供很大帮助。通过最近的研究表明,基于群稀疏正则化的联合代数重建技术(Simultaneous Algebraic Reconstruction Technique,SART)重建在稀疏角度采样背景下可以获得较好的性能。然而,群稀疏正则化在去掉伪影的同时,可能将边缘或细节过度平滑,使得对比度降低,无法获得符合人类视觉效果的高分辨率图像。因此,该文提出了一种基于改进群稀疏正则化的稀疏角度图像重建方法。首先对稀疏角度下的Shepp-Logan模型进行SART重建,再利用群稀疏正则化去除图像伪影,最后利用滚动引导滤波(Rolling Guided Filtering,RGF)进行对比度提升,再次作为SART的输入进行迭代。实验结果表明,该方法在视觉上以及PSNR(Peak Signal-to-Noise Ratio),MSE(Mean Squared Error)和FSIM(Feature Similarity)上均优于其他算法,并且在迭代初始阶段就具有较好的收敛性能。

孔隙结构对黏土持水性及抗剪强度的影响

为研究双峰孔隙结构对非饱和土力学特性的影响,以广西南宁和桂林2种典型双峰孔隙结构黏土为研究对象,分析了其在不同饱和度情况下的抗剪强度特性;辅以滤纸法及核磁共振(nuclear magnetic resonance,NMR)技术探究了2种土体在双峰孔隙结构情况下孔隙水分布状态对强度的影响机理。结果表明:饱和状态下,2种土体试样的T2分布曲线为双峰结构,且土样持水特性整体上均呈现双峰土水特征曲线;2种土体的应力-位移关系变化规律相似,抗剪强度与饱和度密切相关;在饱和度为40%前后土样黏聚力变化趋势发生改变,而内摩擦角则是在饱和度为80%时达到最小值。

基于双通道接收的干扰对消性能分析

为了探究在工程实现中卫星通信地球站使用干扰对消抵抗来自空中平台或周边干扰的可行性,对不同接收环境下的干扰对消性能进行了分析。首先,在假定2个通道中干扰差异被准确估计并补偿的情况下,推导出理论性能的近似计算公式;然后,采用最小均方(least mean square, LMS)自适应滤波器对2个通道干扰的差异进行补偿,完成干扰对消;最后,通过仿真实验对使用LMS自适应滤波器的干扰对消进行验证。结果表明:干扰对消的理论性能在卫星信号与干扰入射夹角大于15°时信噪比恶化可以接近0 dB,而夹角小于15°时信噪比恶化程度明显提高;除了入射夹角的影响外,采用LMS自适应滤波器的干扰对消性能还受算法参数、干扰大小等其他因素的影响,对于固定频点的干扰,在入射夹角大于4°且主通道干信比小于30 dB时,干扰对消后信噪比恶化小于0.6 dB,而且这一结果基本不受采样率的影响。所提出的理论性能近似计算公式可以为干扰对消算法的性能评价提供参考,采用LMS自适应滤波器的干扰对消在算法参数设置合理的情况下可以接近理论性能。

非线性方程组的一个不使用罚函数和filter的算法

给出了求解非线性方程组的一个新算法,首先将非线性方程组转化为一个非线性规划,再使用一个不使用罚函数和filter的算法求解这个非线性规划,在Jacobi矩阵一致列满秩的条件下证明由算法产生序列的极限点是非线性方程组的解.通过在算法中引进二阶校正技术来克服可能的Maratos效应,可以证明这个方法是局部超线性收敛的.

求解非线性互补问题的无导数filter方法

应用filter技术,结合无导数方法和Armijio型条件,构造了一个新的搜索方向,给出了求解非线性互补问题的新算法,并证明了它的全局收敛性.最后的数值实验表明,此算法是可行的.

基于RBF和LSGRG的滤芯托架注塑成型质量控制与优化

针对汽车用复杂交错薄壁格栅的滤芯托架体积收缩率大和生产能耗高的问题,采用有限元仿真分析方法,建立了复杂交错薄壁格栅的滤芯托架仿真分析的有限元模型,对塑件的体积收缩率和注塑过程中的最大锁模力进行了优化,以提高塑件成型质量和降低生产能耗。首先,基于最优拉丁超立方抽样(OLHS)方法和径向基函数(RBF)神经网络模型建立预测模型并对模型精度进行了验证;其次,通过分析20组计算数据并结合工程经验发现体积收缩率和最大锁模力呈相互冲突的关系,且对成型质量和能耗有较大的影响,为此采用大规模广义降阶梯度(LSGRG)技术对预测模型进行多目标寻优并得到最优的工艺参数组合,经过LSGRG方法优化的最大锁模力降低了10.30%,体积收缩率降低了27.61%,优化效果显著。最后,在注塑机上应用优化后的注塑工艺参数生产出了复杂交错薄壁格栅的滤芯托架,产品质量符合要求。提出的基于RBF神经网络模型和LSGRG技术的联合多目标优化方法可为同类型塑件的成型质量控制与优化提供借鉴。

基于多窗口识别的多波长光信号峰值实时检测系统

波分复用(Wavelength Division Multiplexing,WDM)作为光纤通信系统的核心技术之一,为多个波长光信号的复用和传输提供了强有力的解决方案,对复用光信号的解复用和识别是WDM系统需解决的重要问题之一。文中研制了一种针对多波长光信号峰值的实时检测系统,用于实时检测多波长光信号的峰值功率。首先,设计并研制了光纤法布里-珀罗可调谐滤波器(FFP-TF)的驱动控制器和微弱光信号探测器,分别控制FFP-TF的驱动电压使其滤出特定波长的光信号和对滤出光信号的功率进行实时探测;其次,对于光电探测器中实时探测的光信号功率,设计了一种基于多窗口识别的峰值检测方法,使用三个针对波形不同位置的数据筛选窗口,根据实时检测数据来识别波形的变化趋势从而得到峰值强度与位置,进而计算出对应的光信号峰值强度。实验结果显示,所研制的实时检测系统实现了对多波长光信号的实时检测以及峰值的识别,光信号检测强度范围为0~-60 dBm,识别速度较快,对于准周期或周期的多波长光信号的识别具有良好的识别效果。

水中粪大肠菌群四种监测方法的对比分析

粪大肠菌群作为一项能够反映水质卫生安全程度的因子,已成为水体污染评价的重要指标。目前,国内环境监测领域主流的测定方法有多管发酵法、纸片快速法、酶底物法和滤膜法4种。从原理、阳性判别方式、适用范围、检出限、方法特点和干扰因素等方面对上述4种方法进行对比论述,表明了4种方法所具有的特性,总结了实际工作中应当因地制宜选择合适的测定方法,有助于提升监测质量、提高工作效率。

Combined Adaptive Multiple Subtraction Based on Optimized Event Tracing and Extended Wiener Filtering

The surface-related multiple elimination(SRME) method is based on feedback formulation and has become one of the most preferred multiple suppression methods used. However, some differences are apparent between the predicted multiples and those in the source seismic records, which may result in conventional adaptive multiple subtraction methods being barely able to effectively suppress multiples in actual production. This paper introduces a combined adaptive multiple attenuation method based on the optimized event tracing technique and extended Wiener filtering. The method firstly uses multiple records predicted by SRME to generate a multiple velocity spectrum, then separates the original record to an approximate primary record and an approximate multiple record by applying the optimized event tracing method and short-time window FK filtering method. After applying the extended Wiener filtering method, residual multiples in the approximate primary record can then be eliminated and the damaged primary can be restored from the approximate multiple record. This method combines the advantages of multiple elimination based on the optimized event tracing method and the extended Wiener filtering technique. It is an ideal method for suppressing typical hyperbolic and other types of multiples, with the advantage of minimizing damage of the primary. Synthetic and field data tests show that this method produces better multiple elimination results than the traditional multi-channel Wiener filter method and is more suitable for multiple elimination in complicated geological areas.

基于OpenFilters的He-Ne气体辉光压制窄带滤光片

为了解决环形激光器小型化中信号信噪比随腔长减小而下降的问题,设计了一种能压制He-Ne气体放电辉光而不影响激光光强的窄带滤光片。基于Open Filters软件独有的"step"自动膜系设计方法,以初始膜层厚度为线索,设计了符合光谱特性实际应用要求的多个非规整膜系结构。考虑膜层数、膜层厚度及应力等因素,选出便于石英晶振监控的窄带滤光片。在45°的入射角下,该滤光片对s偏振光在632.8nm处的峰值透射率为99.9%,通带半峰值全宽为5.2nm,截止带平均透射率为1.35%。结果表明,该滤光片可有效压制He-Ne气体的放电辉光,提高小型环形激光器的信噪比。

Robust L_1 filtering with pole constraint in a disk via parameter-dependent Lyapunov functions

The problem of robust L 1 filtering with pole constraint in a disk for linear continuous polytopic uncertain systems is discussed. The attention is focused on design a linear asymptotically stable filter such that the filtering error system remains robustly stable, and has a L 1 performance constraint and pole constraint in a disk. The new robust L 1 performance criteria and regional pole placement condition are obtained via parameter-dependent Lyapunov functions method. Upon the proposed multiobjective performance criteria and by means of LMI technique, both full-order and reduced-order robust L 1 filter with suitable dynamic behavior can be obtained from the solution of convex optimization problems. Compared with earlier result in the quadratic framework, this approach turns out to be less conservative. The efficiency of the proposed technique is demonstrated by a numerical example.

A Retrospective Filter Trust Region Algorithm for Unconstrained Optimization

In this paper, we propose a retrospective filter trust region algorithm for unconstrained optimization, which is based on the framework of the retrospective trust region method and associated with the technique of the multi-dimensional filter. The new algorithm gives a good estimation of trust region radius, relaxes the condition of accepting a trial step for the usual trust region methods. Under reasonable assumptions, we analyze the global convergence of the new method and report the preliminary results of numerical tests. We compare the results with those of the basic trust region algorithm, the filter trust region algorithm and the retrospective trust region algorithm, which shows the effectiveness of the new algorithm.

Evaluation of properties for lubricant filter in diesel engines

The properties of lubricant filters in diesel engines directly affect operation of the lubricant system, and lubricant filters are apt to be impacted by many factors. Therefore, scientific and sensible methods evaluating the properties for lubricant filter diesel engines are necessary to monitor filter properties on line and dynamically. This paper applies ferrographic techniques and adopts sampling methods that oil specimens are synchronously obtained in front of and behind filter elements to monitor the filters of ISUZU DA-220 diesel engine in two FD50 forklifts. Results show that the combination of ferrographic techniques and above sampling methods is effective in analyzing the whole operating process of filters used in diesel engines. The service life and ruined type of filter can be estimated through the relationship between ferrographic readings in front and behind of filter and operation time. Furthermore, through a great deal of tests, a series of experimental curves of readings and time and characteristic parameters for filters used in different machines can be gained, which has guiding significance to the selection and maintenance of the filters. But because of the limitation of the ferrographic technique, the debris on the substrate prevents determination of sizes. It is difficult to judge accurately the size of debris that a filter can filter.