Profiling under UNIX by patching

Profiling under UNIX is done by inserting counters into programs either before compiling, during compiling or during assembly. A fourth type of profiling involves monitoring the execution of a program, and gathering relevant statistics during the run. This paper looks at this method and an implementation of it, and discusses its advantages and disadvantages.     

透视Virtex-4超高效且低功耗的奥秘

随着工艺技术越来越小型化、越来越快速,通常会增加功耗,这时在功耗和效能上往往必须有所取舍,因而器件功耗一直是半导体业的首要课题。来自Xilinx的新型Virtex-4FPGA采用创新的架构特性和先进的IC设计技术,可以在显著降低功耗的同时,依然不损害其性能,且和90nm工艺技术特征尺寸减小的趋势不谋而合。本文将探讨XilinxIC设计者如何在高性能Virtex-4FPGA中实现很高的功率效率。     

Who Owns the Data?

The push for data Integration has resulted in another nagging problem: data ownership. Owners have both rights and responsibilities. but these become clouded as organizations try to determine Just who owns the data.     

采用多层式结构的Raychem快速动作表面贴装熔断器

Raychem快速动作表面贴装熔断器是一种应用广泛的新型元件。该熔断器可为使用低于63V直流电源的系统提供过流保护，并有助于开发更可靠的高性能电子产品。目前已应用于手提电脑、多媒体装置。手机等便携式电子产品。     

Etiological Contributions to Heavy Drinking From Late Adolescence to Young Adulthood.

The authors examined genetic and environmental contributions to stability and change in heavy drinking from late adolescence to young adulthood in a sample of 1,152 twin pairs. In men, heavy drinking was similarly heritable at ages 17 (h2 = .57) and 20 (h2 = .39), and its stability owed primarily to common genetic factors. In women, heavy drinking was less heritable than in men at ages 17 (h2 = .18) and 20 (h2 = .30) and its stability was primarily due to enduring shared environmental influences. P3 amplitude, an event-related brain potential marker of alcoholism risk, was less predictive of heavy drinking in women than in men, providing further support for the proposition that biological factors have less impact on heavy drinking in young adult women than in young adult men. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental measurements of orientation and rotation of dense 3D packings of spheres

Many recent advances in the study of granular media have stemmed from the improved capability to image and track individual grains in two and three dimensions. While two-dimensional systems readily yield both translational and rotational motion, a challenge in three-dimensional experiments is the tracking of rotational motion of isotropic particles. We propose an extension of the refractive index matched scanning technique as a method of measuring individual particle rotation. Initial measurements indicate that shear-driven rotational motion may stem from gear-like motion within the shear zone.     

Salt recovery from agricultural drainage water using a liquid film solar-assisted concentrator – Simulation and model validation

Salt management in irrigated agriculture is critical to the economies of the San Joaquin Valley of California and many other areas around the world. Purified salts can be recovered as marketable products through fractional crystallization following concentration of final stage drainage water from integrated on-farm drainage management systems. To obtain recovered salt and use as a commercial product, new systems which can perform with higher efficiency and lower environmental impact than solar evaporation basins or solar ponds that have previously been used for the final stage are in need of development. For this purpose, a number of solar-assisted brine concentration concepts have been explored, including an open liquid film-type using a tilted evaporation surface described here. Model performance was conceptually evaluated and then experimentally verified.A transient model was developed from energy and component mass balances and employed constitutive heat and mass transfer relationships from various other sources for simulating concentration of agricultural drainage water using a liquid film solar-assisted concentrator.Measured maximum evaporation rate and productivity were between 1.3 and 1.5 kg m⁻² h⁻¹, and 80 kg m⁻² over a 7 day experimental period respectively which was about a third better performance compared with a shallow basin horizontal concentrator. Measurements were in good agreement with model predictions: within 2 °C at the peak and 4 °C at the lowest evaporation, and 0.2 kg m⁻² h⁻¹ for evaporation rates during the peak evaporation periods of the day when compared with independent data sets. Cumulative evaporation rates were from 75 to 85 kg m⁻² for the tilted concentrator model and 60 to 65 kg m⁻² for the horizontal concentrator model after 7 days. The tilted concentrator yielded productivity and efficiency that were 33% higher than the horizontal concentrator according to the experimental result for the same period and location.     

Very Low Degree of Energetic Disorder as the Origin of High Mobility in an n‐channel Polymer Semiconductor

Charge transport is investigated in high‐mobility n‐channel organic field‐effect transistors (OFETs) based on poly{[N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene)} (P(NDI2OD‐T2), Polyera ActivInk? N2200) with variable‐temperature electrical measurements and charge‐modulation spectroscopy. Results indicate an unusually uniform energetic landscape of sites for charge‐carrier transport along the channel of the transistor as the main reason for the observed high‐electron mobility. Consistent with a lateral field‐independent transport at temperatures down to 10 K, the reorganization energy is proposed to play an important role in determining the activation energy for the mobility. Quantum chemical calculations, which show an efficient electronic coupling between adjacent units and a reorganization energy of a few hundred meV, are consistent with these findings.     

Quantitative sizing of nano/microparticles with a tunable elastomeric pore sensor

The use of a "size-tunable" polyurethane resistive pulse sensor for quantitative sizing of nano- and microparticles is presented. A linear relationship, as first suggested by Maxwell, between particle volume and change in electric resistance across the pore was observed. Particle sizes were quantified for a given size-tunable membrane, by first creating a linear calibration curve to a series of monodisperse carboxylated polystyrene particles of various diameters and then applying this curve to calculate the size of "unknown" nanoparticles. The diameters of a selection of synthetic and biological particles, being PMMA and nonfunctionalized polystyrene particles, along with biological nanoparticles (adenovirus) were calculated using this methodology. Calculated particle diameters and coefficients of variation were shown to be in good agreement with both transmission electron microscopy and dynamic light scattering results.