混合二肽的场解吸质谱

为了探索生物化学、生物医学中混合寡肽的分析问题,对未衍生的混合二肽场解吸质谱进行了研究(图1和图2)。在图1图2中出现了所有二肽的准分子离子[M+H]~+,除此外还出现了[2M+H]~+、[M_(AB)+H]~+、[M_(AC)+H]~+等集聚离子,这些集聚离子能用于进一步确定各个肽的分子量。     

基亏μC／OS-Ⅱ的高精度超声波测距系统设计

介绍一种以ARM处理器LPC2138为核心,采用超声波回波信号的A／D采样检测原理,实时测距,液晶屏显示的便携式系统。该系统利用ARM处理器处理速度快的优点,自行处理A／D采样速度。系统的测距范围在0．1-4．5m内,测量精度为1cm,实时性好,准确方便,有较高的推广价值。     

基于不完整描述样本的制冷系统故障诊断研究

制冷系统故障信息样本中的部分特征缺失时,已有的故障诊断模型无法使用这些样本。为解决该问题,提出了一种新颖的故障诊断策略。该诊断策略可通过以下步骤实现:(1)在部分问题描述与历史数据库的相互作用及领域知识的基础上,产生了用于特征转换的相似转换矩阵;(2)将不完整描述样本中的未知特征转变为与其相关的已知特征,形成检索目标;(3)通过计算和比较检索目标与数据库中样本间的相似度,得到最佳案例,将该案例中的相应值赋予未知特征;(4)运用已有的故障诊断模型及再生的完整描述样本,对制冷系统进行故障诊断。利用实验数据对该诊断策略进行验证,取得了满意的结果。     

Optimal asymmetrical back plane biasing for energy efficient digital circuits in 28 nm UTBB FD-SOI

In this work we propose an optimal back plane biasing (OBB) scheme to be used in a UTBB FD SOI technology that minimizes the energy per operation consumption of sub threshold digital CMOS circuits. By using this OBB scheme, simulations show that more than 30% energy savings can be obtained with low threshold voltage (LVT) devices in comparison with classic symmetric back plane biasing (SBB) schemes. Additionally, this OBB scheme allows to adjust the performance of the circuit with very small energy penalties. A very simple and intuitive model, for sub threshold digital CMOS circuits, was developed to justify the benefits obtained by OBB. The results predicted by the model are confirmed with extensive simulation results. We show that the OBB approach can be applied easily to a given circuit just based on the information provided by a logic simulation of the circuit (or even an analysis of its structure) and simple electrical simulations of the pMOS and nMOS transistors. Finally, we show that the variability in the energy consumption is improved by using OBB and suggests that new sizing methodologies must be studied to fully benefit from the wide back plane voltage range available in UTBB FD SOI technology for the design of robust energy efficient digital circuits.     

有尾焰动力飞行体电磁脉冲效应数值分析

 利用时域有限差分方法分析了动力段飞行体的等离子体高温尾焰对飞行体电磁脉冲效应的影响。计算结果表明：尾焰的存在极大地改变了飞行体蒙皮上感应电流密度的波形及分布;带尾焰飞行体感应皮电流密度不同于无尾焰时的情况;飞行体蒙皮感应电流密度的波形为衰减振铃信号波形,振铃周期等于电流波在整个飞行体和尾焰长度上流动两次的时间。     

Single-element ultrasonic transducer modeling using a hybrid FD–PSTD method

In a recent publication [E. Filoux, S. Callé, D. Certon, M. Lethiecq, F. Levassort, Modeling of piezoelectric transducers with combined pseudospectral and finite-difference methods, J. Acoust. Soc. Am. 123 (6) (2008) 4165–4173], a new finite-difference/pseudospectral time-domain (FD–PSTD) algorithm was presented and used to model the generation of acoustic waves by a piezoelectric resonator and their propagation in the structure and the surrounding water. In this paper, the model has been extended to simulate the two-dimensional behaviour of a complete single-element transducer, composed of the resonator, a backing and a front matching layer. This further version of the model takes into account the mechanical loss in materials, and enables the calculation of electrical impedance, which is a characteristic of high interest to optimize the performance of ultrasonic transducers. The impedance curves of a PZT [URL: http://www.ferroperm-piezo.com (last viewed 04/2008); B. Jaffe, R.S. Roth, S. Marzullo, Piezoelectric properties of lead zirconate-lead titanate solid-solution ceramics, J. Appl. Phys. 25 (1954) 809–810] plate-based high-frequency transducer, with a 50 MHz thickness resonant frequency, were compared to those of a KLM model [R. Krimholtz, D.A. Leedom, G.L. Matthei, New equivalent circuit for elementary piezoelectric transducers, Electron. Lett. 6 (1970) 398–399] in the one-dimensional case. The acoustical properties were also found to be in good agreement with those obtained using the finite element (FE) method of ATILA^® software in two-dimensional configuration.     

Ultra-High-Pressure Liquid Chromatographic method for the analysis of tocopherols in human colostrum and milk

A rapid, highly sensitive and direct Ultra-High-Pressure Liquid Chromatographic method was developed and validated for quantifying δ-, β + γ-, and α-tocopherol in human colostrum and milk. Two reversed-phase chromatographic columns and two detectors (Fluorescence Detector or FD and Photodiode Detector Array or PDA) were used and both methods were independently validated. Two internal standards were selected according to the detector used. Recoveries ranged from 96.71% to 103.55% and the relative standard deviations for the within-day precision were below 6% (PDA) and 3% (FD). Both approaches enabled to achieve low detection limits, on the order of ng (PDA) or pg (FD). Only 300 μL of sample and a chromatographic run of less than 1.6 min were enough to efficiently quantify the isomers in the colostrum and milk of Spanish women.     

An accurate algorithm to calculate the Hurst exponent of self-similar processes

In this paper, we introduce a new approach which generalizes the GM2 algorithm (introduced in Sánchez-Granero et al. (2008) [52]) as well as fractal dimension algorithms (FD1, FD2 and FD3) (first appeared in Sánchez-Granero et al. (2012) [51]), providing an accurate algorithm to calculate the Hurst exponent of self-similar processes. We prove that this algorithm performs properly in the case of short time series when fractional Brownian motions and Lévy stable motions are considered.We conclude the paper with a dynamic study of the Hurst exponent evolution in the S&P500 index stocks.     

同轴相对论返波管高频特性的数值分析

提出一种数值分析周期慢波结构色散特性的模拟法，先采用时域有限差分法和离散傅里叶变换技术计算含周期慢波结构的谐振腔的谐振频率及谐振场分布，再基于周期慢波电路色散关系的周期性质，利用几个特殊色散点由数值组合技术获得周期慢波线的完整色散关系。数值计算了同轴波纹波导中ＴＭ０ｎ模式的色散关系，亦能用于分析计算任意复杂几何结构的周期慢波线的色散关系。