Uranium measurements using laser-induced breakdown spectroscopy in lithium chloride-potassium chloride salt of pyroprocessing

In pyroprocessing,uranium(U) is recovered from molten LiCl-KCl salt,and,for safeguard purposes,it is important to analyze the U and Plutonium(Pu) concentrations in a timely manner.In the present work,salt samples containing U were fabricated.The laser used in the present work was an Nd:YAG laser with a wavelength of 532 nm,a laser energy on the sample of11.5 mJ,and a pulse repetition rate of 10 Hz.The plasma emission light was measured with an Echelle spectrometer.A total of 100 points on the sample surface were measured as the laser incident position was changed.The U and potassium(K) peaks in the spectrum were identified.Univariate and multivariate analyzes were conducted to determine the accuracy and limit of detection(LOD) of the laser-induced breakdown spectroscopy.     

Application of Cudrania tricuspidata leaf extract as a washing agent to inactivate Listeria monocytogenes on fresh-cut romaine lettuce and kale

The present study aimed to examine the antimicrobial activity of silkworm thorn (Cudrania tricuspidata) leaf extract (CTLE) and its application as a washing agent for fresh-cut romaine lettuce and kale. The antimicrobial activities of CTLE at various concentrations against Listeria monocytogenes were determined using disc diffusion and viable cell count assays, and CTLE exhibited strong inactivation of L. monocytogenes. In particular, after the treatment with 0.4% CTLE, the protein content of L. monocytogenes cells was significantly (P < 0.05) decreased from 507.21 to 254.58 μg mL⁻¹, and damaged cells were observed by scanning electron microscopy. CTLE washing resulted in approximately 2-log reduction of microbial growth, similar to that of 0.01% NaOCl. In addition, CTLE washing did not affect the quality of romaine lettuce and kale. Therefore, these results suggest that CTLE is applicable as a new washing agent for inactivating L. monocytogenes on fresh-cut romaine lettuce and kale.     

Simple reactor for the synthesis of silver nanoparticles with the assistance of ethanol by gas–liquid discharge plasma

Atmospheric pressure plasma technology is gaining increasing importance because it is a simple and tunable synthesis process for the production of metallic nanoparticles. In addition to the development of the power supply, improving the reactor is also one of the main strategies to enhance the utility. In this study, a simple reactor for the gas–liquid discharge plasma induced by argon gas was applied to synthesize silver nanoparticles from silver nitrate (AgNO₃) in solution. An AC power supply with a peak voltage of 3.5 kV was used. The frequency and on-time were set to 50 kHz and 2.5 μs, respectively. The oscilloscope showed that the rising time was approximately 2 μs. The ethanol was used as the source for the reactive reducing agent. No more additional components existed in the solution during the discharge and neither of the electrodes was in contact with the treated solution. The temperature increased by 10 °C within 1min without a cooling system. Carbon was the main impurity and was expected to be produced from the decomposition of the organics under the plasma. The elevated temperature decreased the organic by-products by evaporation and could also decrease the production of carbon. Transmission electron microscopy showed that the spherical silver nanoparticles with a size of approximately 10 nm were synthesized with a crystal structure and that a low concentration of ethanol prefers the production of the mono-dispersed colloid.     

Scalable implementation of multigrid methods using partial semi-aggregation of coarse grids

The Journal of Supercomputing - Multigrid methods are efficient and fast algorithms for solving elliptic equations. However, they suffer from the degradation of parallel efficiency on coarser...     

从日、韩低碳型生态城市探讨相关生态城规划实践

随着全球对气候变化和生态环境的重视,最近国内外的城市发展政策都将焦点集中到低碳生态城市的规划建设上.于是,实现现有城市发展模式向低碳生态城市空间结构的转变就成为城市领域共同探讨的新课题.目前,我国正在积极与新加坡和欧洲国家共同对生态城规划建设进行实践研究,在此背景下,首先对生态规划建设起步较早的日本和韩国的典型低碳型生态城市进行案例分析,然后利用归纳总结的规划要素构想出适合低碳生态城市建设的紧凑型城市空间结构,最后针对中新天津生态城与日本和韩国的低碳生态城市比较分析中得出的问题提出相应的改善建议.     

Low-bandgap copolymers consisting of 2,1,3-benzoselenadiazole and carbazole derivatives with thiophene or selenophene π-bridges

Two donor–acceptor-type alternating copolymers consisting of 2,1,3-benzoselenadiazole and carbazole derivatives with thiophene or selenophene π-bridges were synthesized by Suzuki cross-coupling polymerization, and their optical, electrochemical, and photovoltaic properties were compared. The selenophene π-bridged copolymer (PCz-DSeBSe) exhibited a smaller band-gap (1.82 eV) than the thiophene-bridged polymer (PCz-DTBSe; 1.89 eV). PCz-DSeBSe also showed a deeper highest occupied molecular orbital energy level (−5.36 eV) than PCz-DTBSe (−5.20 eV). Moreover, the PCz-DSeBSe thin film showed higher crystallinity and hole mobility than the PCz-DTBSe thin film. Organic photovoltaic devices were fabricated using the polymers as the donors and [6,6]-phenyl-C₇₁-butyric acid methyl ester (PC₇₁BM) as the acceptor. The device using PCz-DSeBSe showed a higher open circuit voltage (V_oc), short circuit current density (J_sc), and power conversion efficiency (PCE) than that using PCz-DTBSe. The fabricated indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/PCz-DSeBSe:PC₇₁BM/LiF/Al device showed the maximum PCE of 2.88% with a J_sc of 7.87 mA/cm², an V_oc of 0.80 V, and a fill factor of 0.50 under AM 1.5G irradiation (100 mW/cm²).     

Optimal number of minor failures before replacement

This paper extends a replacement model based on failure number to include a repair-cost limit for general failure distributions. The stochastic behaviour of failures and repair costs are modelled by a non-homogeneous Poisson process. An efficient marginal analysis algorithm is presented for finding the optimal failure number for replacement that minimizes the average cost rate.     

A Modification of the Coates Gain Formula for the Analysis of Linear Systems

In this paper, the Coates flow-graph gain formula is modified by the introduction of the loop-set and the two-loop-set, baaed on the concepts of the tree and the two-tree in network topology. The analogy is evident by observing that the two-trees T _ij of a given graph G can be obtained by coalescing vertices i and j of G and thon removing the self-loops. In a similar manner, the two-loop-sets can be obtained from the flow graph by first modifying the graph and then obtaining the loop-sets of tho modified graph. Because of such modification, the derivation of tho gain formula is considerably simplified. Consequently, the evaluation of the terms in the formula becomes easier. Finally, a simple method of determining the number of terms in the formula is derived as a check against possible omission of terms due to carelessness.     

Design of class-based storage racks for minimizing travel time in a three-dimensional storage system

This paper deals with a new storage structure layout method called ‘cubic-in-time’, for minimizing the travel time of selected handling equipment in a three-dimensional palletized storage system. Storage-system design algorithms for minimizing travel times are described, the results are analysed, and some general conclusions are drawn.