230 research outputs found
Plasmonic-Photonic Hybrid Nanodevice
In this thesis, we propose to tackle this important issue by designing and
realizing a novel nano-optical device based on the use of a photonic crystal
(PC) structure to generate an efficient coupling between the external source
and a NA. In this dissertation, the content is arranged into three charpters.
Chapter 1 introduces the theoritical background of this research including
surface plasmon and photonic crystal concepts. This chapter also shows the
design of the hybrid devices and demonstrates the numerical simulation of their
optical properties. Chapter 2 mainly describes the process and the fabricated
samples. The nanodevices are fabricated on an InP membrane substrate. The
critical technology for the fabrication is complex electron beam lithography.
With this technology the alignment of the positions of PC structure and NA is
well controlled. Chapter 3 demonstrates the optical characterizations of the
hybrid nanodevices including far-field characterizations and near-field
characterizations. The far-field measurement is performed by
micro-photoluminescence spectroscopy at room temperature. The results show that
for the defect PC cavities, the presence of the NA influences the optical
properties of the laser, such as lasing threshold and laser wavelength. The
near-field measurement is performed by near-field scanning microscopy, at room
temperature also. The investigation shows that the NA modifies the optical
field distribution of the laser mode. The modification depends on the position
and direction of the NA and it is sensitive to the polarization of the optical
field.Comment: Doctoral thesi
Plasmonic-photonic crystal coupled nanolaser
We propose and demonstrate a hybrid photonic-plasmonic nanolaser that
combines the light harvesting features of a dielectric photonic crystal cavity
with the extraordinary confining properties of an optical nano-antenna. In that
purpose, we developed a novel fabrication method based on multi-step
electron-beam lithography. We show that it enables the robust and reproducible
production of hybrid structures, using fully top down approach to accurately
position the antenna. Coherent coupling of the photonic and plasmonic modes is
highlighted and opens up a broad range of new hybrid nanophotonic devices
Evaluation of the Effect of Saturated Silty and Fine Sand Foundation Improved by Vibro-Flotation in Seismic Area
The improvement of liquefaction foundations in seismic region has been concerning many engineers. The authors had carried out experimental studies on the improvement of saturated silty and fine sand foundations at the suburbs of Beijing by vibroflotation method. The test results are described and the improvement effects are evaluated in this paper
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Bioelectricity generation by wetland plant-sediment microbial fuel cells (P-SMFC) and effects on the transformation and mobility of arsenic and heavy metals in sediment.
Two wetland plant-sediment microbial fuel cell systems (PSM1 and PSM2) and one wetland sediment microbial fuel cell system (SM) were constructed to investigate their electricity production performance and the simultaneous migration and transformation of arsenic and heavy metals in sediment and overlying water, arsenic and heavy metals uptake by plants. The bioelectricity generation was monitored for 175 days, and sediment samples were collected at three time points (64, 125 and 200 days) for the analysis. The results showed that plants improved the efficiency of the electricity production by the fuel cell system. The average output voltage was: PSM1 (0.32 V) > PSM2 (0.28 V) > SM (0.24 V)(P ≤ 0.05).The electricity production of the electrodes and the introduction of plants affected the mobility and transformation of As, Zn and Cd in the sediment, which contributed to their stability in the sediment and reduced the release of these metals into the overlying water column. The bioelectricity production process affected the bioavailability of arsenic and heavy metals in the sediment and attenuated metal uptake by plants, which indicated the potential for remediation of arsenic and heavy metals pollution in sediment
NASA Prediction of Worldwide Energy Resource High Resolution Meteorology Data For Sustainable Building Design
A primary objective of NASA's Prediction of Worldwide Energy Resource (POWER) project is to adapt and infuse NASA's solar and meteorological data into the energy, agricultural, and architectural industries. Improvements are continuously incorporated when higher resolution and longer-term data inputs become available. Climatological data previously provided via POWER web applications were three-hourly and 1x1 degree latitude/longitude. The NASA Modern Era Retrospective-analysis for Research and Applications (MERRA) data set provides higher resolution data products (hourly and 1/2x1/2 degree) covering the entire globe. Currently POWER solar and meteorological data are available for more than 30 years on hourly (meteorological only), daily, monthly and annual time scales. These data may be useful to several renewable energy sectors: solar and wind power generation, agricultural crop modeling, and sustainable buildings. A recent focus has been working with ASHRAE to assess complementing weather station data with MERRA data. ASHRAE building design parameters being investigated include heating/cooling degree days and climate zones
High-throughput cell-based screening reveals a role for ZNF131 as a repressor of ERalpha signaling
<p>Abstract</p> <p>Background</p> <p>Estrogen receptor α (ERα) is a transcription factor whose activity is affected by multiple regulatory cofactors. In an effort to identify the human genes involved in the regulation of ERα, we constructed a high-throughput, cell-based, functional screening platform by linking a response element (ERE) with a reporter gene. This allowed the cellular activity of ERα, in cells cotransfected with the candidate gene, to be quantified in the presence or absence of its cognate ligand E2.</p> <p>Results</p> <p>From a library of 570 human cDNA clones, we identified zinc finger protein 131 (ZNF131) as a repressor of ERα mediated transactivation. ZNF131 is a typical member of the BTB/POZ family of transcription factors, and shows both ubiquitous expression and a high degree of sequence conservation. The luciferase reporter gene assay revealed that ZNF131 inhibits ligand-dependent transactivation by ERα in a dose-dependent manner. Electrophoretic mobility shift assay clearly demonstrated that the interaction between ZNF131 and ERα interrupts or prevents ERα binding to the estrogen response element (ERE). In addition, ZNF131 was able to suppress the expression of pS2, an ERα target gene.</p> <p>Conclusion</p> <p>We suggest that the functional screening platform we constructed can be applied for high-throughput genomic screening candidate ERα-related genes. This in turn may provide new insights into the underlying molecular mechanisms of ERα regulation in mammalian cells.</p
Nonlinear dynamics of global atmospheric and earth system processes
During the grant period, the authors continued ongoing studies aimed at enhancing their understanding of the operation of the atmosphere as a complex nonlinear system interacting with the hydrosphere, biosphere, and cryosphere in response to external radiative forcing. Five papers were completed with support from the grant, representing contributions in three main areas of study: (1) theoretical studies of the interactive atmospheric response to changed biospheric boundary conditions measurable from satellites; (2) statistical-observational studies of global-scale temperature variability on interannual to century time scales; and (3) dynamics of long-term earth system changes associated with ice sheet surges
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