基于弯曲板波的延迟线振荡器的ANSYS仿真

针对复合板结构中弯曲板波谐振频率计算相对复杂的问题,建立并分析了基于弯曲板波延迟线振荡器的理论模型,计算得到A0(0阶反对称)模式板波的谐振频率为41 MHz;为了验证理论分析的结果,利用有限元软件ANSYS建立了基于弯曲板波的延迟线振荡器的3D有限元模型,并对其进行了谐响应分析以及瞬态动力学分析。谐响应分析得到A0模式的谐振频率为37.2 MHz,与理论计算结果的相对误差为9.3%;瞬态动力学分析得到A0模式的谐振频率为39.1 MHz,与理论计算结果的相对误差为4.6%。计算和仿真为基于弯曲板波的延迟线振荡器的结构设计提供了重要的依据。     

Capacity of practical wireless multihop broadcast networks

In a wireless multihop broadcasting scenario, a number of relay nodes may cooperate the source node in order to improve the capacity of the network. However, the imposition of total energy and maximum hop constraints to this system in a practical setting. In this paper, we study an ad-hoc network with infinitely many nodes and analytically find the number and positions of rebroadcasting relay nodes to achieve the optimal broadcast capacity. The interference due to multiple transmissions in the same geographical area is taken into account. According to the results of this theoretical model, we propose two heuristics, one distributed and one centralized, as suboptimal but practical solutions to the relay selection problem in wireless multihop broadcasting. We discuss the broadcast capacity performances and CSI (channel state information) requirements of these algorithms. The results illustrate that the benefits of peer-assisted broadcasting are more pronounced in the centralized relay selection algorithm when compared to the fully randomized and distributed selection under a realistic system model.     

Monocyte, macrophage and foreign body giant cell interactions with molecularly engineered surfaces

To elucidate the mechanisms involved in monocyte/macrophage adhesion and fusion to form foreign body giant cells on molecularly engineered surfaces, we have utilized our in vitro culture system to examine surface chemistry effects, cytoskeletal reorganization and adhesive structure development, and cell receptor-ligand interactions in in vitro foreign body giant cell formation. Utilizing silane-modified surfaces, monocyte/macrophage adhesion was essentially unaffected by surface chemistry, however the density of foreign body giant cells (FBGCs) was correlated with surface carbon content. An exception to the surface-independent macrophage adhesion were the alkyl-silane modified surfaces which exhibited reduced adhesion and FBGC formation. Utilizing confocal immunofluorescent techniques, cytoskeletal reorganization and adhesive structure development in in vitro FBGC formation was studied. Podosomes were identified as the adhesive structures in macrophages and FBGCs based on the presence of characteristic cytoplasmic proteins and F-actin at the ventral cell surface. Focal adhesion kinase (FAK) and focal adhesions were not identified as the adhesive structures in macrophages and FBGCs. In studying the effect of preadsorbed proteins on FBGC formation, fibronectin or vitronectin do not play major roles in initial monocyte/macrophage adhesion, whereas polystyrene surfaces modified with RGD exhibited significant FBGC formation. These studies identify the potential importance of surface chemistry-dependent conformational alterations which may occur in proteins adsorbed to surfaces and their potential involvement in receptor-ligand interactions. Significantly, preadsorption of α₂-macroglobulin facilitated macrophage fusion and FBGC formation readily on the RGD surface in the absence of any additional serum proteins. As α₂-macroglobulin receptors are not found on blood monocytes but are expressed only with macrophage development, these results point to a potential interaction between adsorbed α₂-macroglobulin and its receptors on macrophages during macrophage development and fusion. These studies identify important surface independent and dependent effects in foreign body reaction development that may be important in the identification of biological design criteria for molecularly engineered surfaces and tissue engineered devices. © 1999 Kluwer Academic Publishers     

From relative to absolute quantification of tryptic peptides with tandem mass tags: application to cerebrospinal fluid

Quantification is a major task in proteomics. Among the different analytical strategies to enable peptide and protein quantification, tagging with isotopic labels has emerged as a practical, versatile, and efficient alternative. In particular, isobaric labels, such as TMT or iTRAQ, are now widely employed to make relative comparison of the protein amounts in separate biological samples with tandem mass spectrometry (MS/MS). We used herein a shotgun proteomic approach based on labelling with tandem mass tags (TMTs) for the relative quantification of proteins, and the absolute quantification of their tryptic peptides in human cerebrospinal fluid (CSF). First, the comparison of ante- and post-mortem CSF samples was carried out for the discovery of protein marker candidates of brain-damage disorders. Second, tryptic peptides representative of these candidates were measured in CSF using reporter-ion calibration curves. These works highlighted the advantages and limitations of such strategies for quantification purposes in proteomics.     

Synthesis and photopolymerization of phosphonic acid monomers for applications in compomer materials

Novel methacrylate monomers bearing phosphonic acid groups 1 and 2 as well as new sulfur methacrylates 9 and 10 have been prepared in good yields from thiophenol. They have been fully characterized by ¹H‐NMR, ¹³C‐NMR, ³¹P‐NMR, and HRMS. Their copolymerization with a bis‐GMA : TEGDMA (1 : 1) blend has been investigated with photodifferential scanning calorimetry at 50°C with camphorquinone as a photoinitiator and ethyl 4‐(dimethylamino)benzoate (EDAB) as a coinitiator. The higher the content of acidic monomer 1 or 2 incorporated in the bis‐GMA : TEGDMA (1 : 1) blend, the lower the mixtures reactivity. The phosphonic acid group has been proved to be responsible for this drop of reactivity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Die Wechselwirkung Laurin- und Stearinsäure/Ni-NiO-System des Katalysators

The Interaction between Lauric and Stearic Acid and the Ni-NiO Catalyst System The reactivity of the Ni-NiO catalytic system of following degrees of reduction: 0, 35–65 and 100% Ni with the pure chemical quality lauric and stearic acids during the catalyst passivating conditions 75–115°C were followed in the time period 0–100 hours. The quantity of interaction product of nickel salts of fatty acids in the catalyst is controlled both of the initial reactivity of the Ni-NiO system with the fatty acids and of the kinetics of the zero reaction order. Although the lauric acid is expressively more reactive than the stearic acid, the activity of the in this way prepared catalysts tested in hydrogenation of free fatty acids did not show significant differences.     

Zur Bleichung pflanzlicher Öle II: Kinetik des Bleichprozesses

Bleaching of Vegetable Oils II.: Kinetics of the Bleaching Process The study deals with the kinetics of bleaching. The test-system used rapeseed oil with a low content of erucic acid and added bleaching earth Tonsil Optimum FF. By means of the results obtained an empiric equation was then developed describing the process taking part under the conditions studied.