畸变信号的反演修正在同步测压中的应用

本文说明了同步测压所包含的主要内容以及一套实用的同步测压系统的组成,分析了通过传压管道传递的压力信号产生畸变的原因,指出对畸变信号进行反演修正是同步测压过程中必不可少的关键环节。利用频域修正的方法可以对压力分布同步测量中的畸变信号进行反演,以消除输出信号的幅值误差和相位差,保证各个测压通道得到的信号在时间上具有良好的同步性。这样就可以通过对脉动压力分布进行面积加权积分,得到脉动气动力的时间历程。在对畸变信号进行反演修正时,得到测压系统的频率响应函数是关键,本文介绍了利用比较法来标定频响曲线的装置和方法。并通过实验演示了反演修正的效果,表明本文所采用的同步测压装置具有非常好的同步性能。     

Free Space Measurement Device Independent Quantum Key Distribution with Modulating Retro-Reflectors under Correlated Turbulent Channel

Modulating retro-reflector (MRR), originally introduced to support laser communication, relieves most of the weight, power, and pointing requirements to the ground station. In this paper, a plug-and-play measurement device independent quantum key distribution (MDI-QKD) scheme with MRR is proposed not only to eliminate detector side channels and allow an untrusted satellite relay between two users, but also to simplify the requirements set-ups in practical flexible moving scenarios. The plug-and-play architecture compensates for the polarization drift during the transmission to provide superior performance in implementing the MDI-QKD on a free-space channel, and the MRR device is adopted to relax the requirements on both communication terminals. A double-pass correlated turbulent channel model is presented to investigate the complex and unstable channel characteristics caused by the atmospheric turbulence. Furthermore, the security of the modified MDI-QKD scheme is analyzed under some classical attacks and the simulation results indicate the feasibility under the situation that the system performance deteriorates with the increase of fading correlation coefficient and the turbulence intensity, which provides a meaningful step towards an MDI-QKD based on the moving platforms to join a dynamic quantum network with untrusted relays.     

Enhancing the Limit of Detection for Comprehensive Two‐Dimensional Gas Chromatography (GC×GC) using Bilinear Chemometric Analysis

The chemometric method referred to as the generalized rank annihilation method (GRAM) is used to improve the precision, accuracy, and resolution of comprehensive two‐dimensional gas chromatography (GC×GC) data. Because GC×GC signals follow a bilinear structure, GC×GC signals can be readily extracted from noise by chemometric techniques such as GRAM. This resulting improvement in signal‐to‐noise ratio (S/N) and detectability is referred to as bilinear signal enhancement. Here, GRAM uses bilinear signal enhancement on both resolved and unresolved GC×GC peaks that initially have a low S/N in the original GC×GC data. In this work, the chemometric method of GRAM is compared to two traditional peak integration methods for quantifying GC×GC analyte signals. One integration method uses a threshold to determine the signal of a peak of interest. With this integration method only those data points above the limit of detection and within a selected area are integrated to produce the total analyte signal for calibration and quantification. The other integration method evaluated did not employ a threshold, and simply summed all the data points in a selected region to obtain a total analyte signal. Substantial improvements in quantification precision, accuracy, and limit of detection are obtained by using GRAM, as compared to when either peak integration method is applied. In addition, the GRAM results are found to be more accurate than results obtained by peak integration, because GRAM more effectively corrects for the slight baseline offset remaining after the background subtraction of data. In the case of a 2.7‐ppm propylbenzene synthetic sample the quantification result with GRAM is 2.6 times more precise and 4.2 times more accurate than the integration method without a threshold, and 18 times more accurate than the integration method with a threshold. The limit of detection for propylbenzene was 0.6 ppm (parts per million by mass) using GRAM, without implementing any sample preconcentration prior to injection. GRAM is also demonstrated as a means to resolve overlapped signals, while enhancing the S/N. Four alkyl benzene signals of low S/N which were not resolved by GC×GC are mathematically resolved and quantified.     

革兰氏阴性细菌群体感应信号分子AHL结构类似物的合成及活性研究

基于组氨酸的结构基础,以82.7~85.2%的产率合成了4种N-酰基高丝氨酸内酯(AHL)的结构类似物(His-7,His-8,His-10和His-12),经IR、1H NMR、13 C NMR和MS确认了产物的结构。将四种化合物与紫色色杆菌共培养考察其对革兰氏阴性细菌群体感应系统的影响。结果表明:His-7对紫色色杆菌群体感应系统具有增强信号的作用,能够显著促进菌体中脱氧紫色杆菌素(DVio)的表达。随着分子中脂肪链长度的增加,AHL结构类似物对DVio的表达表现了抑制作用。     

Self-amplifying sensory materials: energy migration in polymer semiconductors

Signal amplification for ultra-sensitive detection has been achieved by energy migration in conjugated semiconducting polymeric assemblies. Critical to optimizing this effect is the synthesis of non-aggregate polymers, the multidimensional directional transport of excited states (excitons), and extending the intrinsic excited state lifetime of conjugated polymers. We developed new water-soluble non-ionic conjugated polymers for use in biosensory applications, which can be used to provide highly sensitive/specific ultra-trace detection that is immune to specificity problems that plauge ionic conjugated polymers.     

基于并联开关技术的ECL电路设计

本文首先指出了采用电压信号的多值电路中,在多个开关串联时存在的问题,进而提出了适合于ECL电路设计的两种将串联开关转换成并联开关的方法,并具体设计了采用并联开关的三值ECL电路。设计实例表明这些方法具有简便、规范的特点。用PSPICE对设计的电路进行模拟得到的结果表明,采用并联开关技术设计的电路不仅具有正确的逻辑功能,而且比采用串联开关设计的电路具有更快的速度。     

模式滤波器在色谱信号除噪中的应用

提出一种模式滤波器方法,用于解决色谱信号中宽带噪声的除噪问题。模式滤波器的应用原理是基于色谱信号与宽带噪声之间的形态差异。工作过程：先采用模式匹配方法识别宽带噪声,再识别各种噪声的起始点与终止点,最后采用线性插值方法重构含噪声的色谱信号。方法具有实现简单、运算速度快、去除噪声能力强等特点。由实际采集的色谱信号经除噪处理后所得的结果表明：模式滤波器比一般滤波器具有更好的除噪效果。     

一种有效提取微弱信号的新方法

根据小波变换能进行时频局部化分析的特性,本文提出一种用小波分段分析处理信号的方法。对任意长度的信号数据,在不增减信号点的情况下,提高分析信号的信噪比,有效地从信号中提取有用信息。将它应用于微弱信号检测,效果满意。     

Optimization of Output Properties for Bias Signal-Modulated in a Single-Mode Laser

Defining the quantity K as the signal-to-noise ratio (SNR) and the normalized intensity fluctuation C(0) of a single-mode laser for bias signal modulation driven by color noises with colored correlation, the whole output properties of the laser system is described by K. It is found that there is a maximum in the curves of K versus D, Q, and io. The optimization parameters are gained.     

Signal‐responsive gating of porous membranes by polymer brushes

Various types of signal‐responsive polymers were grafted on surfaces of porous membranes as polymer brushes. The grafted polymers shrank and extended in response to environmental signals, such as pH, ionic strength, temperature, redox reaction and photo‐irradiation. The pore size was regulated by the extent of the polymer brush. The phenomenon was observed in situ by atomic force microscopy. As a result, the substance permeation through the porous membrane was controlled in response to the signals. The permeation control was rapid in comparison with hygrogel‐type membranes, and was reversibly performed. Copyright © 2000 John Wiley & Sons, Ltd.