Methods for probabilistic modeling of concentrating solar power plants

Probabilistic modeling of concentrating solar power technologies provides important information regarding uncertainties and sensitivities not available from deterministic models. Benefits of using probabilistic models include quantification of uncertainties inherent in the system and characterization of their impact on system performance and economics. This paper presents the tools necessary to conduct probabilistic modeling of concentrating solar technologies. The probabilistic method begins with the identification of uncertain variables and the assignment of appropriate distributions for those variables. Those parameters are then sampled using a stratified method (Latin Hypercube Sampling) to ensure complete and representative sampling from each distribution. Models of performance, reliability, and/or cost are then simulated multiple times using the sampled set of parameters. The results yield a cumulative distribution function that can be analyzed to quantify the probability of achieving a particular metric (e.g., net energy output or levelized energy cost) and to rank the importance of the uncertain input parameters.     

狭长磁电弹性体中Ⅲ型半无限裂纹的场强度因子

通过引入合适的保角映射, 利用复变函数方法研究了裂纹面上受反平面剪应力和面内磁电载荷共同作用下狭长磁电弹性体中半无限裂纹的断裂行为, 给出了磁电全非渗透型边界条件下裂纹尖端场强度因子和能量释放率的解析解。当狭长体高度趋于无限大时, 可得到无限大磁电弹性体中半无限裂纹的解析解。若不考虑磁场或电场作用, 所得解可退化为已知解。通过数值算例, 分析了裂纹面上受载长度、狭长体高度以及磁、电和机械载荷对能量释放率的影响。     

Reduced calcium current density in single myocytes isolated from hypertrophied failing guinea pig hearts

The present study explored the possibility that an alteration in the transmembrane calcium current (ICa), through its ability to modulate Ca2+ release from the sarcoplasmic reticulum, could contribute to the depressed peak [Ca2+]i we previously observed in hypertrophied failing myocardium. Whole-cell patch clamp was used to measure ICa in single guinea pig ventricular myocytes isolated from hearts of normal guinea pigs and from guinea pig hearts in which hypertrophy and failure were induced by gradually developing left ventricular pressure overload subsequent to ascending aortic banding of young animals. Membrane capacitance (Cm) was significantly greater. and ICa, normalized for Cm, was significantly lower in myocytes from hypertrophied failing hearts. Myocytes from hypertrophied failing hearts did not differ significantly from normal myocytes in terms of the voltage-dependence of the activation variable (d) of ICa (except at -30 mV), the time course of removal of inactivation of ICa, and the time constant of decay of ICa. Measurement of the voltage dependence of the inactivation variable (f) of ICa showed that significantly more steady-state inactivation was present at 0, -10, and -20 mV in myocytes from hypertrophied failing hearts. Multiple regression analysis of all data indicated that ICa density decreased with increasing myocyte membrane area (as reflected by Cm) irrespective of any specific effects of hypertrophy and heart failure. We conclude that ICa, normalized for Cm, is significantly reduced in myocytes isolated from hypertrophied failing hearts, probably by a process associated with increased cell size, per se.     

Uniform Voltage Distribution Control for Series Connected DC–DC Converters

This paper investigates applications of current-mode, shared-bus commercial-off-the-shelf (COTS) dc-dc converters to power system architectures configured as parallel-input, series-output (PISO) and series-input, parallel-output (SIPO). By employing a PISO (or SIPO) architecture, current-mode COTS converters can transform their system input voltage to higher (or lower) system output voltage, provide ease and flexibility of power expansion, and preserve system efficiencies equal to those of standalone converters. Nonuniform output (or input) voltages still exist within a PISO (or SIPO) power system using identical converters when the system lacks proper distribution control of the series connected output (or input) voltages-and thus, system reliability suffers from thermal overstress to the converters that contribute a greater portion of the output power. Through unified approaches of voltage distribution control for the PISO and SIPO architectures, a series-connected converter power system attains robust stability and reliability. Two effective approaches to uniform voltage distribution control-the central-limit and maximum-limit voltage distribution-will be discussed. Both computer simulation and experimental prototypes validate both of the uniform voltage distribution power converter architectures.     

Performance of interdigitated nanoelectrodes for electrochemical DNA biosensor

An electrochemical methodology for bio-molecule sensing using an array of well-defined nanostructures is presented. We describe the fabrication by e-beam lithography of nanoelectrodes consisting of a 100 micro m x 50 micro m area containing interdigitated electrodes of 100 nm in width and interelectrode distance of 200 nm. Sensitivity and response time of the nanoelectrodes are compared to the responses of macro- and microelectrodes. The specificity of the sensor is studied by modifying the gold electrodes with DNA. The technique enables to characterize both single and double-stranded DNA of 15 nucleotides. A special electrochemical cell is adapted to control the temperature and measure the DNA concentration by UV analysis. The electrochemical method requires no label on the DNA, only redox mediators were used.     

分水岭算法与其他方法融合的粘连虫卵图像分割

在分水岭算法基础上融合多种方法,试图找出适合粘连虫卵图像的有效分割方法。通过对比实验发现,最小误差阈值法、极小值合并、分水岭等多种方法的融合能够准确地将粘连虫卵图像分离,取得很好的效果。     

Light‐Assisted Charge Propagation in Networks of Organic Semiconductor Crystallites on Hexagonal Boron Nitride

Introducing organic semiconductors as additional building blocks into heterostructures of 2D materials widens the horizon of their applications. Organic molecules can form self‐assembled and self‐aligned crystalline nanostructures on 2D materials, resulting in well‐defined interfaces that preserve the intrinsic properties of both constituents. Thus, organic molecules add unique capabilities to van der Waals heterostructures that have no analogues in inorganic matter. This study explores light‐assisted charge propagation in organic semiconductor networks of quasi‐1D needle‐like crystallites, epitaxially grown on insulating hexagonal boron nitride. Electrostatic force microscopy is employed to demonstrate that upon external illumination it is possible to change the conductivity of organic crystallites by more than two orders of magnitude. Furthermore, by exploiting the highly anisotropic optical properties of the organic nanoneedles, a selective charge propagation along the crystallites is triggered that matches the orientation of the molecular backbones with the incident light's polarization direction. These results demonstrate the possibility to use a “light‐gate” to switch on the conductivity of organic nanostructures and even to guide the charge propagation along desired directions in self‐assembled crystallite networks.     

Automatic system for operational traffic monitoring using very-high-resolution satellite imagery

Vehicle detection from very-high-resolution satellite imagery has received increasing interest during the last few years. In this article, we propose an automatic system for operational traffic monitoring using very-high-resolution optical satellite imagery (0.5–0.6 m resolution) of small highways with low traffic density and a range of different illumination conditions, including cloud-shadowed, hazy, and partially cloudy conditions. The proposed system includes cloud and cloud shadow detection, road detection, and vehicle detection, classification, and counting. The main part of the system is vehicle detection, which is constructed using an elliptical blob detection strategy followed by region growing and feature extraction steps. Vehicular objects are separated from non-vehicular objects using a K-nearest-neighbour classifier, with various classical features used for pattern recognition, as well as some proposed application-specific features, and are also classified according to vehicle size. The fully automatic processing chain has been validated on a selection of satellite scenes from different parts of Norway, including imagery with large amounts of cloud, fog, cloud shadows, and similar conditions that complicate image interpretation. The overall vehicle detection rate was 85.4% and the false detection rate was 9.2%. Overall, this demonstrates the potential of operational traffic monitoring using very-high-resolution satellites.     

On quasi-cyclic codes over {\mathbb{Z}_q}

Quasi-cyclic (QC) codes are a remarkable generalization of cyclic codes. Many QC codes have been shown to be best for their parameters. In this paper, some structural properties of QC codes over the prime power integer residue ring ${\mathbb{Z}_q}$ are considered. An l-QC code of length lm over ${\mathbb{Z}_q}$ is viewed both as in the conventional row circulant form and also as a ${\frac{\mathbb{Z}_q[x]}{\langle x^m-1 \rangle}}$ -submodule of ${\frac{GR(q,l)[x]}{\langle x^m-1 \rangle}}$ , where GR(q, l) is the Galois extension ring of degree l over ${\mathbb{Z}_q}$ . A necessary and sufficient condition for cyclic codes over Galois rings to be free is obtained and a BCH type bound for them is also given. A sufficient condition for 1-generator QC codes to be ${\mathbb{Z}_q}$ -free is given and a formula to evaluate their ranks is derived. Some distance bounds for 1-generator QC codes are also discussed. The duals of QC codes over ${\mathbb{Z}_q}$ are also briefly discussed.