Microelectrodes on a Silicon Chip for Label-Free Capacitive DNA Sensing

This paper presents the experimental characterization of two-terminal microfabricated capacitors for microarrays with an electrical sensing of label-free deoxyribonucleic acid (DNA). So far, such a concept has been demonstrated only in experimental setups featuring dimensions much larger than those typical of microfabrication. Therefore, this paper investigates: 1) the compatibility of the silicon microelectronic processes with biological functionalization procedures; 2) the effects of parasitics when electrodes have realistic dimensions; 3) measurement stability and reproducibility; and 4) the possibility of a fully integrated stand-alone device. The obtained results clearly indicate that two-terminal capacitive sensing with fully integrated electronics represents a viable technology for a DNA label-free detection/recognition.     

A Fully Electronic Label-Free DNA Sensor Chip

This paper presents a microfabricated DNA chip for fully electronic, label-free DNA recognition based on capacitance measurements. The chip has been fabricated in 0.5-mum CMOS technology and it features an array of individually addressable sensing sites consisting of pairs of gold electrodes and addressing logic. Read-out circuitry is built externally using standard components to provide increased experimental flexibility. The chip has been electrically characterized and tested with various solutions containing DNA samples. Significant capacitance variations due to DNA hybridization have been measured, thus showing that the approach represents a viable solution for a single chip DNA sensor array     

Tactile Sensing Using Force Sensing Resistors and a Super-Resolution Algorithm

This paper presents a tactile sensor consisting of an array of force sensing resistors (FSRs). The tactile sensing array can be seen as a coordinated system of touch sensors. The low spatial resolution measured with the FSRs compared to other force or pressure sensors required the use of a super-resolution algorithm. Super-resolution algorithms are often used in digital image processing to enhance the resolution of images. Multiple images taken from slightly different orientations are superimposed in such a way that a single higher-resolution image is obtained. Different touch sensors are briefly discussed and the use of FSRs is motivated. Image-registration techniques are discussed and the super-resolution algorithm developed for the application is presented. Some tests performed using the tactile sensor in a neck palpation device and the results of these tests are also presented.      

In-Circuit Impedance Measurement Using Current Sensing

A novel approach to in-circuit measurement of resistors, capacitors, and inductors was evolved. This approach utilizes current sensing, making possible the measurement of in-circuit components which may be directly shunted by impedances as much as two to three orders of magnitude lower in impedance than the unknown. A minature clip-on probe was developed to facilitate measurements of components mounted on printed circuit boards. A compact impedance comparator was constructed which measured in-circuit components within approximately 2 to 4-percent accuracy over the following ranges: for resistance, 1.5 ? to 1 M?; for capacitance, 100 pF to 60 ?F; and for inductance, 400 ?H to 60 H. Impedances as low as one to three orders of magnitude smaller than the measured element impedance, depending on the probe used, shunted the unknown when the stated accuracy was measured. Much of the quoted inaccuracy is due to the ±3-percent resistance and ±0.1-percent linearity tolerances of the reference resistor which was used for all measurements.     

Real-Time Detection of Sub-ppm Aromatic Compounds in Alcohol by Surface Plasmon Resonance Using Label-Free Graphene

<正>The increasing importance of high-purity isopropyl alcohol(IPA) in semiconductor processing technology has led to a higher demand for technologies capable of detecting impurities in I PA.Although accurate and various impurity detection technologies have been developed,most of them have limitations in real-time and repeatable detection of impurities.Herein,for the first time,surface plasmon resonance(SPR) sensor was developed utilizing graphene transferred Au film(Au/graphene) to detect sub-ppm levels of 2,4-dinitrophenol(2,4-DNP) dissolved in IPA and this sensor demonstrates the ability to detect 2,4-DNP in real-time with great reversibility.     

结合边缘特征的遥感图像融合

曲波(Curvelet)变换是一种更适合于图像处理的多尺度几何分析(MGA)方法,具有很强的方向性.结合 HSI变换将其应用于全色图像和多光谱(MS)图像融合可以更好地表示图像中的有用特征.首先对多光谱图像进行 HSI变换,得到亮度分量 I,对全色图像和 I 分量进行曲波变换得到粗尺度系数和细节尺度系数,对全色图像的粗尺度系数和细节尺度系数进行叠加,计算归一化的全色曲波系数直方图,定义边缘有效因子,利用全色图像的特征信息对融合图像的粗尺度系数进行处理,对细节尺度系数采用函数对弱边缘进行增强,对新的曲波系数设计融合规则进行融合,逆变换后得到新的亮度分量 Inew,用 Inew 替代原亮度分量 I 进行逆 HSI 变换得到最终融合结果,采用统计类指标对融合结果进行评价.实验结果表明,该方法在保持光谱信息和提高空间分辨率上都有较好的效果.     

从AFLP指纹和标记基因序列看我国养殖的四种鲍的亲缘关系

九孔鲍是我国南方主要的鲍养殖对象,皱纹盘鲍与盘鲍则在北方被广泛养殖。对于皱纹盘鲍与盘鲍,尤其是九孔鲍与杂色鲍的分类关系,迄今学术界还存在着不同看法。本文通过AFLP指纹的比较以及细胞核ITS-1和18SrRNA基因片段、线粒体16S rRNA和COI基因片段DNA序列的比较,发现九孔鲍与杂色鲍之间遗传趋异很小,只达到不同地方群体差异的水平;皱纹盘鲍与盘鲍趋异较大,可以认为是属于不同亚种。本研究结果同时表明AFLP技术是进行鲍种质鉴别和遗传多样性研究的有用手段。     

Sensing Capability of Molecularly Imprinted Self-Assembled Monolayer Using Terphenylpropanethiol

A molecularly imprinted self-assembled monolayer (SAM) was fabricated on a gold plate by forming a monolayer with both thiol compound and the template molecule, and removing the template molecules by solvent extraction. 1-Dodecanethiol (DDT), 1-hexadecanethiol (HDT), [1,1′:4′,1′′-terphenyl]-4-thiol (TPT), and [1,1′:4′,1′′-terphenyl]-4-propanethiol (TPPT) were used as the thiol compounds. Cholesterol was used as the template molecule, and cholesterol, cholic acid, and deoxycholic acid were used as the substrate molecules. Cyclic voltammograms were obtained using these imprinted gold plates as a working electrode, with Ag/AgCl reference electrode and Pt counter-electrode. Potassium ferricyanide was used as a background material for oxidation and reduction. These imprinted monolayers were capable of discriminating cholesterol that had been imprinted. The order of sensing capability of the thiol compounds was TPPT > HDT > TPT > DDT.     

Sizing of Wastewater Particles Using the Electrozone Sensing Technique

Electrozone sensing is a rapid and effective method that has been widely used for particle size analysis. This method is based on the Coulter principle, which provides a measure of the solid volume of particles. However, for wastewater particles, due to the high porosity of these particles, the measured Coulter size is significantly less than the physical dimension of these particles. To quantify this effect, the size distribution curves of the sieved wastewater particles were measured using the Coulter particle sizing method, microscopy technique, and sieving methods. A theoretical model was developed by accounting for the porosity of wastewater particles to correlate the physical size of these particles to Coulter size measurement. However, this theoretical model underestimated the size of wastewater particles smaller than 100 μm. Instead, the wastewater particles size (D) for both primary and activated sludge samples was found to be linearly related to the Coulter particle size measurement (d) according to: D = 2.14d with r² = 0.98.     

采用双树轮廓波及压缩传感的多聚焦图像融合

为了拓展压缩传感(CS)的应用潜力,提出一种结合双树轮廓波(DT-Contourlet)及CS的多聚焦图像融合方法.该方法首先采用DT-Contourlet对源图像进行分解,提取图像的多尺度信息及方向信息,克服传统轮廓波变换不具平移不变性的缺点.接着,在DT-Contourlet域,将分解系数看成包含稠密和稀疏两部分:...     

Optimal Scheduling of Casting Sequence Using Genetic Algorithms

Scheduling a casting sequence involving a number of orders with different casting weights and satisfying due dates of is an important optimization problem often encountered in foundries. In this article, we attempt to solve this complex, multi-variable, and multi-constraint optimization problem by using different implementations of genetic algorithms (GAs). In comparison with a mixed-integer linear programming solver, GAs with problem-specific operators are found to provide faster (with a subquadratic computational time complexity) and more reliable solutions to very large (more than 1 million integer variables) casting sequence optimization problems. In addition to solving the particular problem, the study demonstrates how problem-specific information can be introduced in a GA for solving complex real-world problems.     

A Configurable Mixed-Signal Architecture for Label-Free Smart Biosensor Applications

The authors present a novel approach to perform the readout of a genetic sensor by using a low-frequency impedance-sensing technique based on phase-shift measurements. The proposed architecture is sufficiently simple to be fit into an off-the-shelf programmable system-on-chip (PSoC) and yet has been demonstrated to be powerful enough to measure a wide range of capacitance values (100 pF-10 muF ) with a relative error smaller than 2% compared with a high-cost laboratory instrumentation. Field measurements on real sensing structures demonstrated the functionality of the system in saline solutions characterized by different molarities. In this case, the sensor model could not be reduced to a simple capacitance, and the acquired phase shifts were fitted by exploiting a constant-phase element (CPE) model of the sensor. The worst-case relative error on the extracted capacitance for a given molar concentration is 16% for the 0.1-M solution and 11% for the 0.5-M solution. Since DNA hybridization should cause a capacitance change on the order of 25%, our conclusion is that, in principle, the proposed measurement procedure is able to discriminate between single-stranded and hybridized DNAs. The measured phase shifts as a function of frequency allowed us to extract the parameters of the CPE model with an error on the phase that is smaller than 0.4^deg .     

GaAs Quantum Dot Thermometry Using Direct Transport and Charge Sensing

We present measurements of the electron temperature using gate-defined quantum dots formed in a GaAs 2D electron gas in both direct transport and charge sensing mode. Decent agreement with the refrigerator temperature was observed over a broad range of temperatures down to 10 mK. Upon cooling nuclear demagnetization stages integrated into the sample wires below 1 mK, the device electron temperature saturates, remaining close to 10 mK. The extreme sensitivity of the thermometer to its environment as well as electronic noise complicates temperature measurements but could potentially provide further insight into the device characteristics. We discuss thermal coupling mechanisms, address possible reasons for the temperature saturation and delineate the prospects of further reducing the device electron temperature.     

Sensing RF Connector Tightness Using a Grounded Plate Capacitive Structure

This paper describes a grounded plate capacitive sensing technique for monitoring mated RF connector tightness. The capacitive sensing structure and conditioning electronics are fabricated on the surface of a small polystyrene disc which is integrated into the RF connector body. A model of the electrostatic-mechanical system accurately predicts the change in capacitance as a function of the torque applied to tighten the mated connectors. Mechanical displacement in the connector (or, indirectly, axial force on the mated connector) translates to a change in the period of an oscillator drive circuit. The sensing system is measured to provide a transducer sensitivity range from 0.15 pF/N $cdot$ m at the initial connector mating force to 0.74 pF/N $cdot$ m at the high end of mating force.      

First Asian and Microbe-Sourced DNA Sequence Reference Materials Released

<正>The Asian-sourced DNA sequence reference materials(BW-5201)and DNA sequence reference materials of 0157 genome colibacillus(BW-5202)were released by National Institute of Metrology of China(NIM)and Shenzhen Huada Gene Research Institute on June 19,2015.This is the first time to release these reference materials in the world,providing a reference for the gene sequencing and data analysis in     

Specific and Sensitive Fluorescence Anisotropy Sensing of Guanine-Quadruplex Structures via a Photoinduced Electron Transfer Mechanism

Fluorescence anisotropy (FA) is a homogeneous, ratiometric, and real-time analytical technology. By selective labeling of a guanine (G)-quadruplex motif with tetramethylrhodamine (TMR), here, it is established that a large reduction in FA response can be specifically associated with the unfolding → folding transition of G-quadruplex structures. On the basis of fluorescence intensity, polarization and lifetime analysis, and molecular docking simulation, the mechanism was found to be that the labeled fluorophore (TMR) can intramolecularly interact with adjacent G bases in an unfolded G-quadruplex motif, which allows for the photoinduced electron transfer (PET) occurring between the fluorophore and G bases, leading to a short fluorescence lifetime. Upon the folding of the motif to form a stable G-quadruplex structure, the intramolecular interactions and the concomitant PET could be eliminated with an increased fluorescence lifetime, leading to a large reduction in the FA response. On the basis of this mechanism, a novel, specific, and sensitive FA approach was developed for the detection of biologically and functionally important G-quadruplex structures. The approach is examined and validated using one normal G-quadruplex motif, five mutants, and six small cations and is potentially applicable to the study of G-quadruplexes at single molecule level, ligand screening, profiling of highly ordered DNA nanostructures, and biosensing.     

多模光纤传感器复合材料固化实时监测研究

设计了一种新型光纤传感器，提出通过测量光纤末端近场模斑谱监测光纤埋置周转树脂折射率的变化。     

基于下采样的特征融合遥感图像语义分割

本文提出了一种基于下采样的特征融合遥感图像语义分割模型,该模型在编解码结构基础上,将高分辨率原始图像引入"下采样"模块提取低级语义特征,在此基础上,将输出的低级语义特征通过MobileNetV2和空间金字塔池化进一步提取多尺度高级语义细节特征,然后,将这些高级语义特征和直接从下采样模块提取的低级语义特征融合并进行特征图分割.最后,在"CCF卫星影像的AI分类与识别竞赛"的数据集上取得了93%的训练准确率以及91%的预测准确率.     

利用极点顺序的多边形顶点凹凸性判别算法

提出一种根据多边形各个极点在顶点序列中的先后顺序确定多边形方向的算法.对于多边形顶点凹凸性的判别,提出通过确定某个顶点与其相邻两顶点构成三角形的方向,进而利用多边形方向与该三角形方向是否相同而确定该顶点凹凸性的方法.该算法包括了点包含的判别.试验表明,该算法不含乘法运算,使运算高效稳定.