690 research outputs found
Compensation of Loss and Stimulated Emission of Surface Plasmon Polaritons
Surface plasmon polaritons (SPPs) have become in recent years an important research topic because of their interesting, physics and exciting potential applications, ranging from sensing and biomedicine to nanoscopic imaging and information technology. However, many applications of surface plasmon polaritons are hindered by one common cause—absorption loss in metal.
Over the years, numerous proposals have been made on how to conquer the plasmon loss. In this dissertation, (1) the known solutions to the loss problem by adding optical gain have been reviewed; (2) the properties of surface plasmon polaritons are studied theoretically, and the solution of the controversy regarding the direction of the k vector of a wave with a strong evanescent component in an active medium has been developed; (3) the propagation of surface plasmon polaritons without gain has been studied experimentally, and it is demonstrated that an addition of highly concentrated rhodamine 6G chloride dye to the PMMA film adjacent to a silver film can cause 30% elongation of the propagation length of surface plasmon polaritons; (4) the propagation of SPPs with optical gain has been studied experimentally and compared to the theoretical predictions: the level of gain achieved in our experiments (≈ 420 cm−1 at λ=594 nm) was, in principle, sufficient to compensate the propagation loss of surface plasmon polaritons in high-quality silver films; and (5) the stimulated emission of surface plasmon polaritons characterized by a distinct threshold in the input-output dependence and narrowing of the emission spectrum has been demonstrated.
The realized compensation of the metallic absorption loss by gain and the observed stimulated emission of surface plasmon polaritons pave the road to a broad range of applications of metamaterials and nanoplasmonic devices
The End of the Nobel Era and the Reconstruction of the World Republic of Letters
In their article The End of the Nobel Era and the Reconstruction of the World Republic of Letters Guohua Zhu and Yonghua Tang critically examine mechanisms of cultural hegemony associated with the Nobel Prize in Literature from a neocolonial lens. Borrowing from Casanova\u27s idea of the World Republic of Letters and its attentiveness to geopolitics, the essay proceeds to reconstruct the dialectical relations between the nation and the world. It does so, in the first place, by documenting and analyzing the process of negotiation and bargaining entailed in the construction of global cultural hegemony and thereby examine the functions and boundaries of hegemony. Further, it reveals how colonial apparatuses of understanding continue to limit the ways in which we imagine the world and sustain the power relations that ought to be questioned, challenged, and broken. Ultimately, the essay aims to provide a multi-dimensional and multi-layered vision of the World Republic of Letters that is genuinely multi-polar
From the Other to the Master Narrative : the Chinese Journey of the Frankfurt School
In their article, From the \u27Other\u27 to the \u27Master Narrative\u27: The Chinese Journey of the Frankfurt School, Guohua Zhu and Xiangchun Meng discuss the Chinese reception of Frankfurt School and the Maoist historical context. Chinese scholars take the narrow view of the Frankfurt School theories as a depoliticized instrument to explain Chinese practice, particularly in the realm of mass culture. Furthermore, the Frankfurt School has encountered the powerful political and ideological legacy of Maoism, which not only dictates instrumentalist view, but also predisposes to a nationalistic attitude that pits Chinese exceptionalism against universalism, including the Frankfurt School and other western Marxist theories. It is thus imperative to disentangle the complex relationship of Critical Theory and Maoism in China. Recontexualizing the broader history of Chinese reception and response to western theories and knowledge will help renew conversations with the West in humanities and social sciences
Dynamic responses of axially moving telescopic mechanism for truss structure bridge inspection vehicle under moving mass
Dynamic responses of a telescopic mechanism for truss structure bridge inspection vehicle under moving mass are investigated under the assumption of Euler-Bernoulli beam theory. Equations of motion for the telescopic mechanism are derived using the Hamilton’s principle. The equations are transformed into discretized equations by employing the Galerkin’s method. The eigenfunctions of the beams are derived based on the kinetic and dynamic boundary conditions. The time-dependent features of the eigenfunctions are taken into account. The discretized equations are solved utilizing the Newmark-β method. Numerical results are presented to explore the influence of the moving mass on the dynamic responses of the telescopic mechanism and find appropriate mass-moving strategy to avoid large vibration. The results show that the vibrations when the mass doesn’t move synchronously with the telescopic beam are not always the minimum; on the other hand, the mass moving in the same direction of the telescopic beam will bring in stronger vibration
Influence of ventilation on flow-induced vibration of rope-guided conveyance
The behavior of rope-guided conveyances is so complicated that the rope-guided hoisting system hasn’t been understood thoroughly so far. In this paper, with user-defined functions loaded, ANSYS FLUENT 14.5 was employed to simulate the flow-induced vibration of rope-guided conveyances under different ventilation air speed. With rope-guided mine cages taken into account, results show that the ventilation affects the lateral displacement of conveyance greatly. With the increase of ventilation air speed, the maximum lateral and side displacements of ascending conveyances also increase, while those of descending conveyances don’t always increase, because the ventilation air flows downcast. With the thrust bearings equipped with the hoist rope attachment and the tail rope attachment, the rotation of conveyance about vertical axis is very small
Genome-wide linkage analysis of the tracking of systolic blood pressure using a mixed model
BACKGROUND: Elevated blood pressure in middle age is a major risk factor for subsequent cardiovascular complications. An important longitudinal characteristic of blood pressure is the "tracking phenomenon". Tracking is defined as the persistence of the rank of a person's blood pressure level in a group over a long period of time. In this analysis, we used the Framingham data to investigate whether there are some genes responsible for this phenomenon. RESULTS: Both two-point and multipoint linkage analyses were applied to family members with complete data only and to all family data with missing values imputed by a Gaussian model. The results of two-point linkage analysis indicated that two loci for linkage with the intercept were on chromosomes 10 and 13, and two loci for linkage with both slope and intercept were on chromosomes 1 and 3. Multipoint linkage analysis indicated only one region, 200–240 cM on chromosome 1, to be linked with both intercept and slope. For the intercept of SBP, the highest LOD (4.43) was found at 214 cM when missing data were imputed, and the highest LOD (2.81) was at 231 cM for the complete case data. For the slope of SBP, the highest multipoint LODs were 3.63 at 227 cM and 2.02 at 234 cM for the complete case data and imputation data, respectively. CONCLUSION: One or more genes in the range of 200–240 cM on chromosome 1 may be related to the tracking phenomenon of SBP
- …