High-performance implementation of regular and easily scalable sorting networks on an FPGA

The paper is dedicated to fast FPGA-based hardware accelerators that implement sorting networks. The primary emphasis is on the uniformity of core components, feasible combinations of parallel, pipelined and sequential operations, and the regularity of the circuits and interconnections. The paper shows theoretically, and based on numerous experiments, that many existing solutions that are commonly considered to be very efficient have worthy competitors that are better for many practical problems. We compared the even–odd merge and bitonic merge sorting networks (which are among the fastest known) with the even–odd transition network, which is often characterized as significantly slower and more resource consuming. We found that the latter is the most regular network that can be implemented very efficiently in FPGA, so we are proposing new, easily scalable hardware solutions and processing techniques based on this. Finally, the paper provides four main contributions and suggests: (1) a regular hardware implementation of resource and time effective architectures based on the even–odd transition network; (2) a pipelined implementation of even–odd transition networks; (3) a pre-processing technique that enables sorting to be further accelerated; (4) combinations of this technique with a merge sort, an address-based sort, a quicksort, and a radix sort.     

Real-Time Imaging Using a High-Power Monochromatic Terahertz Source: Comparative Description of Imaging Techniques with Examples of Application

Gradually appearing high-power terahertz sources require the development of adequate imaging techniques. This paper describes four imaging techniques (with a thermal recorder, temperature-sensitive phosphor plates, a visible-light thermal sensitive Fizeau interferometer, and an uncooled microbolometer array) applied with the Novosibirsk terahertz free electron laser as a radiation source. The space and time resolutions of the devices were examined thoroughly. Examples of the application of these techniques, including in-line holography and real-time moving-objects detection, are given.     

用激光散斑技术监测药物作用下淋巴流的变化

本文采用激光散斑零点法（ZCLS）监测了在不同剂量的盐酸异丙肾上激素作用下大鼠肠系腹上淋巴流的流速变化,并与传统的单帧分析方法获得的结果进行比较,两种方法获得的平均流速变化一致,开始时随着盐酸异丙肾上腺素浓度的增加（10^-1mol/L～10^-5mol/L）,淋巴流平均流速减小,在浓度为10^5mol/L时,淋巴流平均流速减小达到显著性水平,当浓度继续增加至10^4mol/L,平均流速开始增加,但未达到显著性水平,不同的是,采用本文方法同时获得了淋巴流流速的实时动态特征,在药物作用下,其动态特征也发生了改变,本方法将有可能为生理学和药理学研究提供一种简便的淋巴流流速监测方法。     

Hydrothermal Synthesis and Photocatalytic Activity of Whisker-Like Rutile-Type Titanium Dioxide

Nanowhiskers of rutile-type titanium dioxide (TiO₂) were synthesized by a simple hydrothermal treatment of a water-soluble titanium–glycolate complex at 473 K. The aspect ratio of the obtained rutile particles could be controlled by changing the concentration of the glycolic acid additive in the starting aqueous solution of the titanium complex. According to high-resolution transmission electron microscopy, whisker-like nanoparticles grow along the c -axis of rutile, the side facets of which are (110), (−110), (1–10), and (−1–10). Glycolic acid controls promotion of the rutile particles in the specified direction due to its preferred adsorption on the titanium-rich facets. Evaluation of the photocatalytic activity of the synthesized TiO₂ was performed in terms of decomposition of oxalic acid in an aqueous system under ultraviolet irradiation. It turned out that this particular whisker-like shape is responsible for the tremendous enhancement of rutile photocatalytic activity, and even rutile samples with low surface area demonstrated photocatalytic performance comparable with one of the best nanosized anatase photocatalytic materials. Therefore, it can be concluded that the (110) rutile facet plays an important role in the photocatalytic oxidation reaction, and that it exhibits higher photocatalytic activity than the (001) facet in the decomposition of oxalic acid.     

A mechanistic perspective of atmospheric oxygen sensitivity on composite energetic material reactions

Solid energetic composites have been used and studied in standard air environments, yet the contribution of atmospheric oxygen to reactive material combustion has not been investigated. This study experimentally examines the effect of atmospheric oxygen concentration (4% or 93% oxygen) on energy propagation of nanometric aluminum with copper oxide (Al + CuO), iron oxide (Al + Fe₂O₃), calcium iodate (Al + Ca(IO₃)₂), and iodine pentoxide (I₂O₅). In all cases energy propagation was examined in terms of flame speed and higher in the high oxygen environments. However, the convectively dominant reactions showed a smaller percent increase in flame speed mainly attributed to the reaction mechanism.     

Study of hydrogen production and storage based on aluminum–water reaction

The rate and yield of hydrogen production from the reaction between activated aluminum and water has been investigated. The effect of different parameters such as water–aluminum ratio, water temperature and aluminum particle size and shape was studied experimentally. The aluminum activation method developed in-house involves 1%–2.5% of lithium-based activator which is diffused into the aluminum particles, enabling sustained reaction with tap water or sea water at room temperature. Hydrogen production rates in the range of 200–600 ml/min/g Al, at a yield of about 90%, depending on operating parameters, were demonstrated. The work further studied the application in proton exchange membrane (PEM) fuel cells in order to generate green electric energy, demonstrating theoretical specific electric energy storage that can exceed batteries by 10–20 folds.     

Design of a Compact Ceramic High-Temperature Heat Exchanger and Chemical Decomposer for Hydrogen Production

This article describes a compact silicon carbide ceramic, high-temperature heat exchanger for hydrogen production in the sulfur iodine thermochemical cycle, and in particular, to be used as the sulfuric acid decomposer. In this cycle, hot helium from a nuclear reactor is used to heat the SI (sulfuric acid) feed components (H₂O, H₂SO₄, SO₃) to obtain appropriate conditions for the SI decomposition reaction. The inner walls of the SI decomposer channels are coated with platinum to catalytically decompose sulfur trioxide into sulfur dioxide and oxygen. Hydrodynamic, thermal, and the sulfur trioxide decomposition reaction were coupled for numerical modeling. Thermal results of this analysis are exported to perform a probabilistic mechanical failure analysis. This article presents the approach used in modeling the chemical decomposition of sulfur trioxide. Stress analysis of the design is also presented. The second part of the article shows the results of parametric study of the baseline design (linear channels). Several alternate designs of the chemical decomposer channels are also explored. The current study summarizes the results of the parametric calculations whose objective is to maximize the sulfur trioxide decomposition by using various channel geometries within the decomposer. Based on these results, a discussion of the possibilities for improving the productivity of the design is also given.