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Jos M. Galn Ramn Abascal 《International journal for numerical methods in engineering》2002,53(5):1145-1173
A finite element formulation is applied to study Lamb wave scattering in homogeneous and sandwich isotropic plates. Dispersion curves are calculated in a simple and automatic way by solving a quadratic eigenproblem. A meshing criterion to obtain accurate results with linear and quadratic elements is provided. An absorbing boundary condition for semi‐infinite plates is derived from this formulation by means of a truncated normal mode expansion technique, where the finite element eigenvectors are used instead of the analytical expressions for the normal modes. This non‐reflecting boundary condition is directly applicable to study Lamb wave reflection by simple obstacles such as a flat edge. In order to tackle Lamb wave diffraction problems by defects with more complex geometries, a hybrid boundary element‐finite element formulation is developed. The validity and accuracy of both formulations are checked thoroughly with a series of test problems studied by other researchers. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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Fiach C. O'Mahony Toms C. O'Riordan Natalia Papkovskaia Vladimir I. Ogurtsov Joe P. Kerry Dmitri B. Papkovsky 《Packaging Technology and Science》2004,17(4):225-234
An optical oxygen analyser was used in two small‐scale industrial trials to non‐destructively assess the quality of packaged convenience foods and packaging process. Beef lasagne packed under 70% vacuum and cooked under standard sous vide conditions was monitored for residual oxygen, using disposable sensors incorporated in each pack and a benchtop optical oxygen analyser. High levels of residual oxygen close to ambient were determined in the majority of packs after packaging, as opposed to anticipated levels of 4–5%. Residual oxygen was monitored over product shelf‐life (4 weeks at +4–10°C) along with measurement of microbial growth and lipid oxidation in food by conventional destructive methods. Oxygen levels in packs went down to almost zero between weeks 2 and 3 indicating deterioration of packaged product. Correlation between oxygen profiles and the rate of microbial growth and lipid oxidation was established. The optical oxygen sensor system was shown to provide valuable information about performance of the packaging process, product storage conditions and food quality in a convenient and cost‐efficient fashion and non‐destructively. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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A.M. Patti A.L. Santi R. Gabrieli S. Fiamma M. Cauletti A. Pan 《Water research》1987,21(11):1335-1338
The hepatitis A virus (HAV) and poliovirus 1 were added to estuarine water samples and their stability in maintenance medium was compared to that in water samples untreated and treated by heat and filtration. The inactivation curves show that the inactivating factor is biological in nature. 相似文献
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A virus extraction method which combines elution with a 10% beef-extract with agitation and sonication, was used to recover enteric viruses from 4 types of sludge sampled at a treatment plant and from 2 types of stored sludge. Titers were measured using BGM continuous cell line with the plaque technique. No viruses were recovered from any of the 16 stored sludge samples analysed. All samples of fresh mixed sludge and of activated sludge contained viruses. 44% of digested sludge and 10% of dehydrated sludge samples were positives for virus. 相似文献
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Feng Li Huiling Chen Yejun Zhang Zhong Chen Zhi‐Ping Zhang Xian‐En Zhang Qiangbin Wang 《Small (Weinheim an der Bergstrasse, Germany)》2012,8(24):3832-3838
Assembling nanoparticles (NPs) into ordered architectures remains a challenge in the field of nanotechnology. Templated strategies have been widely utilized for NP assembly. As typical biological nanostructures, virus‐based NPs (VNPs) have shown great promise in templating NP assembly. Here it is illustrated that the VNP of simian virus 40 (SV40) is a powerful scaffold in directing the assembly of 3D hybrid nanoarchitectures with one NP encapsulated inside as a core and a cluster of gold NPs (AuNPs) on the outer surface of the SV40 VNP as a shell, in which the core NPs can be CdSe/ZnS quantum dots (QDs), Ag2S QDs, or AuNPs. The assembling of AuNPs onto the SV40 VNP surface is determined by the interactions between the AuNPs and the amine groups on the outer surface of SV40 VNPs. It is expected that the VNP guided 3D hybrid nanoarchitectures provide ideal models for NP interaction studies and open new opportunities for integrating various functionalities in NP assemblies. 相似文献
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目的：考察琐琐葡萄总黄酮体外抗乙型肝炎病毒(HBV)的效果。方法：用HBV DNA转染人肝癌细胞所得的HepG 2.2.15细胞株为模型,ELISA法测定用药后8d细胞培养上清液中HBsAg和HBeAg含量,计算琐琐葡萄总黄酮对HBsAg和HBeAg分泌的抑制率,荧光定量PCR法测定HBV DNA的变化,MTT比色法检测细胞毒性。结果：琐琐葡萄总黄酮在12.5～100μg/mL范围内,均能不同程度地减少细胞培养上清液中HBsAg和HBeAg的含量,且细胞毒性小,半数中毒剂量(TC50)为284.91μg/mL,对HBsAg半数有效剂量(IC50)为327.56μg/mL、对HBeAg为215.34μg/mL,对HBsAg治疗指数(TI)为0.87、对HBeAg治疗指数为1.32;总黄酮质量浓度100μg/mL时对HBV DNA的抑制率为47.63%。结论：琐琐葡萄总黄酮具有一定的体外抗HBV作用。 相似文献
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