Fractal Metamaterial Absorber with Three-Order Oblique Cross Dipole Slot Structure and its Application for In-band RCS Reduction of Array Antennas

To miniaturize the perfect metamaterial absorber, a fractal three-order oblique cross dipole slot structure is proposed and investigated in this paper. The fractal perfect metamaterial absorber (FPMA) consists of two metallic layers separated by a lossy dielectric substrate. The top layer etched a three-order oblique fractal-shaped cross dipole slot set in a square patch and the bottom one is a solid metal. The parametric study is performed for providing practical design guidelines. A prototype with a thickness of 0.0106λ (λ is the wavelength at 3.18 GHz) of the FPMA was designed, fabricated, measured, and is loaded on a 1×10 guidewave slot array antennas to reduce the in-band radar cross section (RCS) based on their surface current distribution. Experiments are carried out to verify the simulation results, and the experimental results show that the absorption at normal incidence is above 90% from 3.17 to 3.22GHz, the size for the absorber is 0.1λ×0.1λ, the three-order FPMA is miniaturized 60% compared with the zero-order ones, and the array antennas significantly obtain the RCS reduction without the radiation deterioration

Flutter analysis for bridge decks using Lattice Boltzmann Method

Aiming at using the Lattice Boltzmann Method for flutter analysis of the bridge decks, a fluid- structure interaction algorithm is developed  within the framework of multiple –relaxation- time Lattice Boltzmann  Method. In the present algorithm, the unsteady fluid dynamics  is computed by the extended two-dimensional Lattice Boltzmann Method by incorporating the dynamic Smagorinsky subgrid scale  model, while the structure is modelled by an elastically suspended rigid body and its dynamic analysis is performed by using a Runge–Kutta method. A staggered coupling strategy is adopted to couple the fluid solver and the structure solver. To demonstrate the applicability of the presented algorithm, flutter analyses of the Second Forth Road Bridge and the Guamá River Bridge are employed. The numerical results are compared with wind tunnel measurements. It is shown that the  presented algorithm has a good prediction for the flutter onset  velocities of the Forth Road Bridge and the Guamá River Bridge and thus indicates, to a certain extent, the applicability of the presented algorithm

Neoproterozoic subduction along the Ailaoshan zone, South China : geochronological and geochemical evidence from amphibolite

This study was supported by China Natural Science Foundation (41190073 and 41372198), National Basic Research Program of China (2014CB440901) and Natural Environment Research Council (grant NE/J021822/1).Lenses of amphibolites occur along the Ailaoshan suture zone at the southwestern margin of the Yangtze Block, South China. Petrological, geochemical and zircon U-Pb geochronological data indicate that they are divisible into two coeval groups. Group 1, represented by the Jinping amphibolite, has mg-number of 71-76 and (La/Yb)cn ratios of 7.2-7.7, and displays a geochemical affinity to island arc volcanic rocks. Group 2 amphibolites occur at Yuanyang and are characterized by high Nb contents (14.3-18.4 ppm), resembling Nb-enriched basalts. The epsilon(Nd)(t) values for Group 1 range from -3.45 to -2.04 and for Group 2 from +4.08 to +4.39. A representative sample for Group 1 yields a U-Pb zircon age of 803 7 Ma, whereas two samples for Group 2 give U-Pb zircon ages of 813 +/- 11 Ma and 814 +/- 12 Ma. Petrogenetic analysis suggests that Group 1 originated from an orthopyroxene-rich source and Group 2 from a mantle wedge modified by slab-derived melt. In combination with other geological observations, these amphibolites are inferred to constitute part of an early Neoproterozoic (similar to 815-800 Ma) arc-back-arc basin system. The Neoproterozoic amphibolites and related rocks along the Ailaoshan zone may be the southward extension of the Neoproterozoic supra-subduction zone that developed along the western margin of the Yangtze Block. (C) 2014 Elsevier B.V. All rights reserved.PostprintPeer reviewe

Experimental Analysis for Factors Affecting the Repeatability of Plastics Injection Molding Tests on the Self-developed Apparatus

To improve the repeatability of the injection molding test result, the affecting factors were investigated by means of experiments. Besides the traditional processing parameter, the factors of test conditions were also considered. In order to focus on the molding process rather than the molded part, the curve measurement of the melt pressure at the entrance to the nozzle was used as the output characteristic. Experiments for polypropylene (PP) showed that the injected volume was the key processing parameter. Within the test conditions, the injection number is the most important factor. According to the analysis the operating procedure was improved effectively. Doi: 10.12777/ijse.5.1.6-11 [How to cite this article: Huang, Y., Li, D., Liu, Y. (2013). Experimental Analysis for Factors Affecting the Repeatability of Plastics Injection Molding Tests on the Self-developed Apparatus. International Journal of Science and Engineering, 5(1),6-11. Doi: 10.12777/ijse.5.1.6-11

Thermal discharge-created increasing temperatures alter the bacterioplankton composition and functional redundancy

Additional file 1: Table S1. Measurements of geochemical factors of the 10 sampling sites. Table S2. Pearson correlations between seawater temperature and biogeochemical variables. Figure S1. Pearson correlations between seawater temperature and bacterial abundance (A), DNA yield (a proxy for microbial biomass) (B), and grazing rate (C). Figure S2. Multivariate regression tree (MRT) of bacterial diversity associated with driving biogeochemical factors

Relaxation behavior of biaxially stretched PLA film during the heat setting stage

In this paper, the relaxation behavior of polylactic acid (PLA) film in the heat-setting stage of biaxial stretching was studied. Firstly, the polylactic acid casting films were stretched synchronously in different ratios. We found that the Machine direction (MD) and Transverse direction (TD) stress relaxation curves exhibited a separation trend with the increase in the stretching ratio, and the relaxation amplitude increased gradually. Then, the stress relaxation curves were fitted by the expansion exponential equation (KWW equation). The results showed that the coefficient used to characterize the homogeneity of stress relaxation increased with the increase in the stretching ratio, and the homogeneity in Machine direction was better than that in Transverse direction. Finally, we analyzed the evolution of rheological units and the activation energy spectrum during stress relaxation. We found that the volume of rheological units gradually decreased with the increase in the stretching ratio. The activation energy spectrum exhibited a Gaussian distribution, and the symmetry axis of distribution curves shifted to the high energy. The above results would be of great significance in further understanding the deformation mechanism of polylactic acid film during biaxial stretching and providing theoretical guidance for the preparation of high-performance BOPLA films

Effect of Yugan Sanjie decoction on expressions of regulatory T cells, serum P21 protein and vascular endothelial growth factor in mice with hepatocellular carcinoma

Purpose: To investigate the effect of Yugan Sanjie decoction on the expressions of regulatory T cells (Tregs), serum P21 protein and vascular endothelial growth factor (VEGF) in mice with hepatocellular carcinoma. Methods: A total of forty specific-pathogen-free (SPF) Kunming mice were randomly assigned to four groups of 10 mice each. Except for normal control group, the other three groups were transfected with hepatoma-22 (H22) cells to establish a mouse model of liver cancer. Mice in the cyclophosphamide group was given cyclophosphamide at a dose of 20 mg/kg daily intragastrically, while those in decoction group were treated with Yugan Sanjie decoction (0.4 ml/kg/day) intraperitoneally. After 30 days of treatment, serum levels of CD4+ Th17, CD4+CD25+ Treg, Th17/Treg, TNF-α, and VEGF were determined. Results: There was lower serum level of CD4+ Th17 in the decoction group than in negative control and cyclophosphamide groups (p < 0.05). However, higher serum levels of CD4+CD25+ Treg and Th17/Treg were seen in the decoction group, relative to the negative control and cyclophosphamide groups (p < 0.05). Serum TNF-α was also markedly elevated in decoction group, when compared with negative control and cyclophosphamide groups (p < 0.05). Serum VEGF was markedly lower in decoction group than in negative control and cyclophosphamide groups, and was appreciably lower in cyclophosphamide group than in negative control group (p < 0.05). Conclusion: Yugan Sanjie decoction effectively alleviates clinical symptoms of LC, and improves immune function of mice by regulating serum levels of T lymphocytes. These findings provide scientific support for a new treatment strategy

Pairwise and Parallel: Enhancing the Key Mismatch Attacks on Kyber and Beyond

Key mismatch attacks resilience is a great concern for KEMs in the NIST PQC standardization process. In key mismatch attacks, the adversary aims to recover the reused key by sending special form of ciphertexts to the target party and observing whether the shared key matches his guesses or not. In this paper, we propose pairwise-parallel key mismatch attacks on Kyber and other lattice-based KEMs. The strategy is to recover partial information about multiple secret key coefficient-pairs in a parallel way per query. We realize the required multi-value key mismatch oracle in a simple key exchange scenario and experimentally validate our proposed attacks. Our attacks greatly reduce the number of queries required to recover the full secret key. Specifically, compared with state-of-the-art key mismatch attacks on CPA-secure Kyber, our attacks reduce the number of queries by 95% with computational complexity $2^{32}$. Then we employ the post-processing with lattice reduction to further minimize the number of queries. The results show we only need 78 queries to recover the full secret key with a lattice reduction cost of $2^{32}$. Moreover, our proposed pairwise-parallel attack method can be directly applied to enhance the PC oracle-based SCA against CCA-secure Kyber, reducing the number of queries/traces by 16.67%

Effect of Surcharge on the Stability of Rock Slope under Complex Conditions

In this paper, a general analytical expression for the factor of safety of the rock slope against plane failure is proposed, incorporating most of the practically occurring under complex conditions such as depth of tension crack, depth of water in tension crack, seismic loads and surcharge. Several special cases of this expression are established, which can be found similarly to those reported in the literature. A detailed parametric analysis is presented to study the effect of surcharge on the stability of the rock slope for practical ranges of main parameters such as depth of tension crack, depth of water in tension crack, the horizontal seismic coefficient and the vertical seismic coefficient. The parametric analysis has shown that the factor of safety of the rock slope decreases with increase in surcharge for the range of those parameters in this paper. It is also shown that the horizontal seismic coefficient is the most important factor which effects on the factor of safety in the above four influence factors. The general analytical expression proposed in this paper and the results of the parametric analysis can be used to carry out a quantitative assessment of the stability of the rock slopes by engineers and researchers

Quantitative Analysis of Volatile Impurities in Diallyldimethylammonium Chloride Monomer Solution by Gas Chromatography Coupled with Liquid-Liquid Extraction

The quantitative analysis method for volatile impurities in diallyldimethylammonium chloride (DADMAC) monomer solution was established in this paper. The volatile impurities were quantitatively analyzed with trichloromethane as extraction solvent and n-hexane as internal standard by using gas chromatography (GC) coupled with solvent extraction, and the chromatographic conditions, quantitative methods, and extraction conditions were systematically investigated in detail. The results showed that excellent linear relationships of 5 volatile impurities (dimethylamine, allyldimethylamine, allyl chloride, allyl alcohol, and allyl aldehyde) were obtained in the range of 1–100 mg·L−1. The method also showed good specificity, recovery (95.0%–107.5%), and relative standard deviation (RSD, 1.40%–7.67%). This method could accurately detect the whole volatile impurities in DADMAC monomer solution quantitatively in one time with a low detection limit. Furthermore, this method is conducive to the preparation of highly pure DADMAC monomer and the development of national and international standards of the DADMAC monomer product quality, and the results could provide a strong foundation for the regulation and mechanism research of impurities on monomer reactivity in polymerization