778 research outputs found
Efficient Volumetric Method of Moments for Modeling Plasmonic Thin-Film Solar Cells with Periodic Structures
Metallic nanoparticles (NPs) support localized surface plasmon resonances
(LSPRs), which enable to concentrate sunlight at the active layer of solar
cells. However, full-wave modeling of the plasmonic solar cells faces great
challenges in terms of huge computational workload and bad matrix condition. It
is tremendously difficult to accurately and efficiently simulate near-field
multiple scattering effects from plasmonic NPs embedded into solar cells. In
this work, a preconditioned volume integral equation (VIE) is proposed to model
plasmonic organic solar cells (OSCs). The diagonal block preconditioner is
applied to different material domains of the device structure. As a result,
better convergence and higher computing efficiency are achieved. Moreover, the
calculation is further accelerated by two-dimensional periodic Green's
functions. Using the proposed method, the dependences of optical absorption on
the wavelengths and incident angles are investigated. Angular responses of the
plasmonic OSCs show the super-Lambertian absorption on the plasmon resonance
but near-Lambertian absorption off the plasmon resonance. The volumetric method
of moments and explored physical understanding are of great help to investigate
the optical responses of OSCs.Comment: 11 pages, 6 figure
Hierarchical layered double hydroxide nanocomposites: structure, synthesis and applications
Layered double hydroxide (LDH)-based nanocomposites, constructed by interacting LDH nanoparticles with other nanomaterials (e.g. silica nanoparticles and magnetic nanoparticles) or polymeric molecules (e.g. proteins), are an emerging yet active area in healthcare, environmental remediation, energy conversion and storage. Combining advantages of each component in the structure and functions, hierarchical LDH-based nanocomposites have shown great potential in biomedicine, water purification, and energy storage and conversion. This feature article summarises the recent advances in LDH-based nanocomposites, focusing on their synthesis, structure, and application in drug delivery, bio-imaging, water purification, supercapacitors, and catalysis. This journal i
Vertical Structure of Neutrino-Dominated Accretion Disk and Applications to Gamma-Ray Bursts
We revisit the vertical structure of neutrino-dominated accretion flows in
spherical coordinates. We stress that the flow should be geometrically thick
when advection becomes dominant. In our calculation, the luminosity of neutrino
annihilation is enhanced by one or two orders of magnitude. The empty funnel
along the rotation axis can naturally explain the neutrino annihilable
ejection.Comment: 13 pages, 3 figures, accepted for publication in Ap
Quantum fluctuation of ferroelectric order in polar metals
Since its discovery a decade ago, "polar metallic phase" has ignited
significant research interest, as it further functionalizes the switchable
electric polarization of materials with additional transport capability,
granting them great potential in next-generation electronic devices. The polar
metallic phase is an unusual metallic phase of matter containing long-range
ferroelectric (FE) order in the electronic and atomic structure. Distinct from
the typical FE insulating phase, this phase spontaneously breaks the inversion
symmetry but without global polarization. Unexpectedly, the FE order is found
to be dramatically suppressed by carriers and destroyed at moderate ~10%
carrier density. Here, we propose a general mechanism based on carrier-induced
quantum fluctuations to explain this puzzling phenomenon. Basically, the
quantum kinetic effect would drive the formation of polaronic quasi-particles
made of the carriers and their surrounding dipoles. The disruption in dipolar
directions can therefore weaken or even destroy the FE order. We demonstrate
such polaron formation and the associated FE suppression via a simple model
using exact diagonalization, perturbation, and quantum Monte Carlo approaches.
This quantum mechanism also provides an intuitive picture for many puzzling
experimental findings, thereby facilitating new designs of multifunctional FE
electronic devices augmented with quantum effects.Comment: 12 pages, 6 figures in tota
Restenosis treatments using nanoparticle-based drug delivery systems
Restenosis, the re-narrowing of a blood vessel after removal of atherosclerotic plaque, is a major limitation of surgical treatments for atherosclerosis. Various attempts to prevent or treat restenosis by pharmacological or mechanical approaches have had limited success in clinical trials. Hence, there is wide interest in developing new strategies to prevent or treat restenosis. This review discusses 'a new-generation therapy' that uses functional nanoparticles to effectively deliver active drug molecules. The potential platforms for nanoparticle-based solutions to restenosis include organic (e.g. polymers, liposomes, and proteins) and inorganic nanoparticles (e.g. layered double hydroxides, titanium oxide nanotubes, and magnetic nanoparticles,). Many in vitro and in vivo studies based on these platforms demonstrate the feasibility and potential of using nanoparticle drug delivery systems for preventing or treating restenosis, but as yet few have reached clinical trials. It is suggested that using inorganic nanoparticles to target deliver multi-functional drugs will be a promising approach to preventing or treating restenosis
Dynamic changes of main metabolic substances during anther-derived embryos development in loquat (Eriobotrya japonica Lindl. cv. ‘Dawuxing’)
The main metabolic substances changes during the development process of anther-derived embryos in loquat (Eriobotrya japonica Lindl. cv. ‘Dawuxing’) were studied. These include water contents, dry mass contents, carbohydrates, soluble proteins and nucleic acids. In the developmental stages of anther-derived embryos, the fresh weight and the dry mass contents increased gradually with the anther-derived embryos development as a whole. Soluble sugars, soluble protein and nucleic acid were closely related to the development and maturation of embryos, changing significantly in metabolism at the important development turning points. Soluble sugar, fructose and starch contents had the same change trend. The two accumulation peaks appeared at globular and cotyledon stages. During the development of loquat anther embryos, the dynamics of protein synthesis were roughly in "S" shape. The two accumulation peaks appeared at globular and cotyledon stage, respectively, in accordance with the change of sugar and starch. Alkaline protein contents were higher than acidic protein contents. Alkaline protein contents and total soluble protein contents had the same change trend during the development process. DNA contents and total nucleic acid contents had the same change trend during the development of anther-derived embryos. The DNA synthesis peaks appeared at the embryogenic callus stage. RNA contents were very low at embryogenic callus stage and cotyledon stage, while DNA was actively synthesized at the two stages.Key words: Eriobotrya japonica, anther culture, embryos, metabolic substances
- …