735 research outputs found
Longitudinal quantum plasmons in copper, gold, and silver
The propagation of plasmonic waves in various metallic quantum nanostructures
have considered attention for their applications in technology. The quantum
plasmonic properties of metallic nanostructures in the quantum size regime have
been difficult to describe by an appropriate model. Here the nonlocal quantum
plasmons are investigated in the most important metals of copper, gold, and
silver. Dispersion properties of these metals and propagation of longitudinal
quantum plasmons in the high photon energy regime are studied by a new model of
nonlocal quantum dielectric permittivity. The epsilon near zero properties are
investigated and the spectrum and the damping rate of the longitudinal quantum
plasmons are obtained in these metals. The quantum plasmon s wave function is
shown for both classical and quantum limits. It is shown that silver is the
most appropriate for quantum metallic structures in the development of next
generation of quantum optical and sensing technologies, due to low intrinsic
loss
Plasma-enabled growth of ultralong straight, helical, and branched silica photonic nanowires
This article reports on the lowerature inductively coupled plasma-enabled synthesis of ultralong (up to several millimeters in length) SiO2 nanowires, which were otherwise impossible to synthesize without the presence of a plasma. Depending on the process conditions, the nanowires feature straight, helical, or branched morphologies. The nanowires are amorphous, with a near-stoichiometric elemental composition ([O] / [Si] =2.09) and are very uniform throughout their length. The role of the ionized gas environment is discussed and the growth mechanism is proposed. These nanowires are particularly promising for nanophotonic applications where long-distance and channelled light transmission and polarization control are required
Diffusivity of adatoms on plasma-exposed surfaces determined from the ionization energy approximation and ionic polarizability
Microscopic surface diffusivity theory based on atomic ionization energy
concept is developed to explain the variations of the atomic and displacement
polarizations with respect to the surface diffusion activation energy of
adatoms in the process of self-assembly of quantum dots on plasma-exposed
surfaces. These polarizations are derived classically, while the atomic
polarization is quantized to obtain the microscopic atomic polarizability. The
surface diffusivity equation is derived as a function of the ionization energy.
The results of this work can be used to fine-tune the delivery rates of
different adatoms onto nanostructure growth surfaces and optimize the
low-temperature plasma based nanoscale synthesis processes.Comment: Published versio
Electron-conduction mechanism and specific heat above transition temperature in LaFeAsO and BaFe(2)As(2) superconductors
The ionization energy theory is used to calculate the evolution of the
resistivity and specific heat curves with respect to different doping elements
in the recently discovered superconducting Pnictide materials. Subsequently,
the electron-conduction mechanism in the Pnictides above the structural
transition temperature is explained unambiguously, which is also consistent
with other strongly correlated matter, such as cuprates, manganites, titanates
and magnetic semiconductors. Therefore, the superconductivity is not uniquely
corresponds to the electronic properties above the structural transition
temperature. Detailed prediction are given on these compounds for various
doping elements, namely, La(Sm,Ce,Ba,Sr,Ca)FeAsO(F,Cl,Br) and
Ba(Sr,Ca,K,Rb,Cs)Fe(2)As(2).Comment: Published online: J. Supercond. Nov. Magn. (2009
Plasma-Controlled Metal Catalyst Saturation and the Initial Stage of Carbon Nanostructure Array Growth
The kinetics of the nucleation and growth of carbon nanotube and nanocone arrays on Ni catalyst nanoparticles on a silicon surface exposed to a low-temperature plasma are investigated numerically, using a complex model that includes surface diffusion and ion motion equations. It is found that the degree of ionization of the carbon flux strongly affects the kinetics of nanotube and nanocone nucleation on partially saturated catalyst patterns. The use of highly ionized carbon flux allows formation of a nanotube array with a very narrow height distribution of half-width 7 nm. Similar results are obtained for carbon nanocone arrays, with an even narrower height distribution, using a highly ionized carbon flux. As the deposition time increases, nanostructure arrays develop without widening the height distribution when the flux ionization degree is high, in contrast to the fairly broad nanostructure height distributions obtained when the degree of ionization is low
Hierarchical bi-dimensional alumina/palladium nanowire nano-architectures for hydrogen detection, storage and controlled release
Nano Technology and Gas Plasma as Novel Therapeutic Strategies for Ovarian Cancer Oncotherapy
Ovarian cancer (OC) is associated with a high rate of resistance to most chemotherapy drugs and thus novel therapies are crucial to overcoming these obstacles. The technological advances in nanotechnology make it possible to adapt these approaches for the treatment of chemo-resistant OC. In parallel, it is also evident that this emerging technology plays crucial roles in other medical areas including wound healing, treatment of viral infection and applications in dentistry. With the advancement of nanotechnology, nano dependent therapies are attractive viable alternatives to conventional therapies for various diseases, especially cancers. Nanoparticles (NPs) are a suitable platform for cytotoxic agent delivery and aiding early diagnosis of disease, which can lead to improving outcomes for these patients. Gas plasma oncotherapy is an innovative modality and shows huge potentials in cancer treatment and may emerge as the fifth cancer treatment modality together with surgery, radiotherapy, chemotherapy, targeted therapy and immunotherapy. The combination of nanoparticle and gas plasma therapy could lead to the discovery of an alternative effective treatment approach in these resistant tumors leading to improvement of OC prognosis. Here, we highlighted the two novel modalities with known multiple biological targets and underlying mechanisms appropriate for their application in OC treatment. This chapter explores the utility of combination or multimodal of novel nanotherapeutic agents in the treatment of OC
Microplasmas for Advanced Materials and Devices
Microplasmas are low-temperature plasmas that feature microscale dimensions and a unique high-energy-density and a nonequilibrium reactive environment, which makes them promising for the fabrication of advanced nanomaterials and devices for diverse applications. Here, recent microplasma applications are examined, spanning from high-throughput, printing-technology-compatible synthesis of nanocrystalline particles of common materials types, to water purification and optoelectronic devices. Microplasmas combined with gaseous and/or liquid media at low temperatures and atmospheric pressure open new ways to form advanced functional materials and devices. Specific examples include gas-phase, substrate-free, plasma-liquid, and surface-supported synthesis of metallic, semiconducting, metal oxide, and carbon-based nanomaterials. Representative applications of microplasmas of particular importance to materials science and technology include light sources for multipurpose, efficient VUV/UV light sources for photochemical materials processing and spectroscopic materials analysis, surface disinfection, water purification, active electromagnetic devices based on artificial microplasma optical materials, and other devices and systems including the plasma transistor. The current limitations and future opportunities for microplasma applications in materials related fields are highlighted.</p
Lung Cancer Oncotherapy through Novel Modalities: Gas Plasma and Nanoparticle Technologies
Cold atmospheric pressure plasma (CAP) is emerging as new healthcare technology and it has a high potential through physical and chemical effects for cancer treatment. Recently, CAP, plasma activated liquid (PAL), and nanomaterial have been significant advances in oncotherapy. Reactive oxygen-nitrogen species (RONS), electrical field, and other agents generated by CAP interact with cells and induce selective responses between the malignant and normal cells. Nanomedicine enhances therapeutic effectiveness and decreases the side effects of traditional treatments due to their target delivery and dispersion in tumor tissue. There are various nanocarriers (NCs) which based on their properties can be used for the delivery of different agents. The combination of gas plasma and nanomaterials technologies is a new multimodal treatment in cancer treatment, therefore, is expected that the conjunction of these technologies addresses many of the oncology challenges. This chapter provides a framework for current research of NC and gas plasma therapies for lung cancer. Herein, we focus on the application of gas plasmas and nanotechnology to drug and gene delivery and highlight several outcomes of its. The types and features of the mentioned therapeutics strategy as novel classes for treating lung cancer individually and synergistic were examined
Future antiviral polymers by plasma processing
Coronavirus disease 2019 (COVID-19) is largely threatening global public health, social stability, and economy. Efforts of the scientific community are turning to this global crisis and should present future preventative measures. With recent trends in polymer science that use plasma to activate and enhance the functionalities of polymer surfaces by surface etching, surface grafting, coating and activation combined with recent advances in understanding polymer-virus interactions at the nanoscale, it is promising to employ advanced plasma processing for smart antiviral applications. This trend article highlights the innovative and emerging directions and approaches in plasma-based surface engineering to create antiviral polymers. After introducing the unique features of plasma processing of polymers, novel plasma strategies that can be applied to engineer polymers with antiviral properties are presented and critically evaluated. The challenges and future perspectives of exploiting the unique plasma-specific effects to engineer smart polymers with virus-capture, virus-detection, virus-repelling, and/or virus-inactivation functionalities for biomedical applications are analysed and discussed
- …