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排序方式: 共有181条查询结果,搜索用时 359 毫秒
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Fundamental advances have been made in the spatially resolved chemical analysis of polymer thin films. Tip‐enhanced Raman spectroscopy (TERS) is used to investigate the surface composition of a mixed polyisoprene (PI) and polystyrene (PS) thin film. High‐quality TER spectra are collected from these nonresonant Raman‐active polymers. A wealth of structural information is obtained, some of which cannot be acquired with conventional analytical techniques. PI and PS are identified at the surface and subsurface, respectively. Differences in the band intensities suggest strongly that the polymer layers are not uniformly thick, and that nanopores are present under the film surface. The continuous PS subsurface layer and subsurface nanopores have hitherto not been identified. These data are obtained with nanometer spatial resolution. Confocal far‐field Raman spectroscopy and X‐ray photoelectron spectroscopy are employed to corroborate some of the results. With routine production of highly enhancing TERS tips expected in the near future, it is predicted that TERS will be of great use for the rigorous chemical analysis of polymer and other composite systems with nanometer spatial resolution.  相似文献   
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A self-tuning control scheme that is suitable for enhancing system performance in the presence of variations in operating conditions is proposed. Unlike most of the existing self-tuning control strategies, the proposed scheme makes use of a linear combination of two signals as the variable of a discrete-time model chosen to describe the system dynamics. This approach enables the system performance to be enhanced without increasing the computational time required. Experimental studies involving the control of a DC servo motor shows that the proposed scheme is effective  相似文献   
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A gel imaging method was employed to quantitate the GFP that had been subjected to denaturation and degradation treatments. This method is able to differentiate the nativity of GFP by relating the observed changes in the position of fluorescent bands which is unable to be detected using the spectrofluorometric method.  相似文献   
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翟贺  彭铁红  赵晨  周思昂 《钢结构》2014,(3):48-50,71
针对大檩条屋面结构体系的特点,应用有限元计算软件,对结构体系变形特点、大檩条隅撑组合梁进行系统分析,并对大檩条简化计算方法加以讨论,得出若干设计中需要注意问题的处理意见。  相似文献   
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Characteristics of a phage effective for colibacillosis control in poultry   总被引:1,自引:0,他引:1  
BACKGROUND: Colibacillosis is one of the main causes of economic loss in the poultry industry worldwide. Although antibiotics have been used to control this infection, the emergence of antibiotic‐resistant bacteria poses a threat to animal and human health. Phage therapy has been reported as one of the potential alternative methods to control bacterial infections. However, efficient phage therapy is highly dependent on the characteristics of the phage isolated. In the present study the characteristics of a lytic phage, ØEC1, which was found to be effective against the causative agent of colibacillosis in chickens in a previous in vivo study, are reported. RESULTS: Examination by transmission electron microscopy revealed that ØEC1 is a DNA phage belonging to the Podoviridae family. ØEC1 showed an optimum multiplicity of infection of 0.1‐1. The latent period of ØEC1 was 25 min, with a burst size of 200 particles per infected cell. Under the experimental conditions the maximum adsorption rate for ØEC1 was 99.9% within 8 min. ØEC1 demonstrated an optimum phage lytic activity at pH 6‐9 and 25–41 °C. CONCLUSION: These characteristics can serve as a guideline for selection of effective candidates for phage therapy, in this case for collibacillosis control in chickens. Copyright © 2012 Society of Chemical Industry  相似文献   
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The C-terminal domain of Nipah virus (NiV) nucleocapsid protein (NP401–532) was inserted at the N-terminus and the immunodominant loop of hepatitis B core antigen (HBc). The stability of NP401–532 increased tremendously when displayed on the HBc particles. These particles reacted specifically with the swine anti-NiV and the human anti-HBc antisera.  相似文献   
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