scholarly journals Biodistribution of60Co–Co/Graphitic-Shell NanocrystalsIn Vivo

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Li Zhan ◽  
Qi Wei ◽  
Geng Yanxia ◽  
Xu Junzheng ◽  
Wu Wangsuo
Keyword(s):  
Graphitic Carbon ◽  
Nano Materials ◽  
Core Size ◽  
Cover Layer ◽  
The Core ◽  
Cvd Method ◽  
Graphitic Shell ◽  
20 Nm ◽  
Total Excretion

The magnetic nano-materials, Co/graphitic carbon- (GC-) shell nanocrystals, were madeviachemicalvapour deposition (CVD) method, and their biodistribution and excretion in mice were studied by using postintravenously (i.v.) injecting with60Co–Co/GC nanocrystals. The results showed that about 5% of Co was embedded into graphitic carbon to form multilayer Co/GC nanocrystals and the size of the particle was ~20 nm, the thickness of the nanocrystal cover layer was ~4 nm, and the core size of Co was ~14 nm. Most of the nanocrystals were accumulated in lung, liver, and spleen after 6, 12, 18, and 24 h afteri.v.with60Co–Co/GC nanocrystals. The nanoparticles were cleared rapidly from blood and closed to lower level in 10 min after injection. The60Co–Co/GC nanocrystals were eliminated slowly from body in 24 h after injection, ~6.09% of60Co–Co/GC nanocrystals were excreted by urine, ~1.85% by feces in 24 h, and the total excretion was less than 10%.

scholarly journals Mono-dispersed Ag nanoparticles decorated graphitic carbon nitride: An excellent lubricating additive as PPESK composite film

Friction ◽  
2021 ◽  
Author(s):  
Beibei Chen ◽  
Mengjie Zhang ◽  
Kan Zhang ◽  
Zhe Dong ◽  
Jiaye Li ◽  
...  
Keyword(s):  
Composite Film ◽  
Ag Nanoparticles ◽  
Carbon Nitride ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Great Promise ◽  
Theoretical Simulation ◽  
Heavy Loads ◽  
20 Nm ◽  
Ball On Disc

AbstractStudies show that two dimensional (2D) nanomaterial and its hybrid have a great promise in tribology for the special laminar microstructure. However, the majority of performed investigations about 2D graphitic carbon nitride (g-C3N4) nanosheets are most focused on energy storage, catalysis, adsorption, rarely tribology. In the present study, g-C3N4 supporting mono-dispersed Ag nanoparticle hybrid (g-C3N4/Ag) is prepared, and its microstructure and chemical composition are determined. More specifically, the tribological performance as the lubricating additive of poly phthalazinone ether sulfone ketone (PPESK) composite is investigated using the ball-on-disc friction tester. Moreover, the corresponding enhancement mechanism is well proposed based on the experimental analysis and theoretical simulation. Obtained results show that Ag nanoparticles with a size of about 10–20 nm are homogeneously anchored on g-C3N4 nanosheets, favoring for good compatibility between g-C3N4/Ag and PPESK. It is found that when 0.3 wt% of g-C3N4/Ag is added to PPESK, the friction coefficient and wear rate of PPESK decrease by 68.9% and 97.1%, respectively. These reductions are mainly attributed to the synergistic self-lubricating effect of Ag nanoparticles and g-C3N4 nanosheet, the formation of transfer film, as well as the limited effect of g-C3N4/Ag on the shear deformation of PPESK composite film. Furthermore, it is found that the proposed g-C3N4/Ag-PPESK composite still keeps reasonable friction-reducing and wear-resistant properties under heavy loads and high rotating speeds. The present study demonstrates that the proposed g-C3N4/Ag hybrid is an excellent lubricating additive for polymer composites.

scholarly journals Geometrical Scaling of Antiresonant Hollow-Core Fibers for Mid-Infrared Beam Delivery

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 420
Author(s):  
Ang Deng ◽  
Wonkeun Chang
Keyword(s):  
Structural Parameters ◽  
Transmission Band ◽  
Confinement Loss ◽  
Hollow Core ◽  
Core Size ◽  
Core Diameter ◽  
Mid Infrared ◽  
The Core ◽  
Tubular Type ◽  
Beam Delivery

We numerically investigate the effect of scaling two key structural parameters in antiresonant hollow-core fibers—dielectric wall thickness of the cladding elements and core size—in view of low-loss mid-infrared beam delivery. We demonstrate that there exists an additional resonance-like loss peak in the long-wavelength limit of the first transmission band in antiresonant hollow-core fibers. We also find that the confinement loss in tubular-type hollow-core fibers depends strongly on the core size, where the degree of the dependence varies with the cladding tube size. The loss scales with the core diameter to the power of approximately −5.4 for commonly used tubular-type hollow-core fiber designs.

scholarly journals The hourglass effect in hierarchical dependency networks

2017 ◽  
Vol 5 (4) ◽  
pp. 490-528 ◽  
Author(s):  
KAESER M. SABRIN ◽  
CONSTANTINE DOVROLIS
Keyword(s):  
Low Complexity ◽  
Core Size ◽  
Original Network ◽  
Hierarchical Network ◽  
Modular Systems ◽  
The Core ◽  
Dependency Networks ◽  
Dependency Network ◽  
Hierarchical Dependency ◽  
Almost All

AbstractMany hierarchically modular systems are structured in a way that resembles an hourglass. This “hourglass effect” means that the system generates many outputs from many inputs through a relatively small number of intermediate modules that are critical for the operation of the entire system, referred to as the waist of the hourglass. We investigate the hourglass effect in general, not necessarily layered, hierarchical dependency networks. Our analysis focuses on the number of source-to-target dependency paths that traverse each vertex, and it identifies the core of a dependency network as the smallest set of vertices that collectively cover almost all dependency paths. We then examine if a given network exhibits the hourglass property or not, comparing its core size with a “flat” (i.e., non-hierarchical) network that preserves the source dependencies of each target in the original network. As a possible explanation for the hourglass effect, we propose the Reuse Preference model that captures the bias of new modules to reuse intermediate modules of similar complexity instead of connecting directly to sources or low complexity modules. We have applied the proposed framework in a diverse set of dependency networks from technological, natural, and information systems, showing that all these networks exhibit the general hourglass property but to a varying degree and with different waist characteristics.

scholarly journals All-fiber passively Q-switched ytterbium doped double-clad fiber lasers: experiment And modeling.

2021 ◽  
Author(s):  
Yi Lu
Keyword(s):  
Pulse Energy ◽  
Traveling Wave ◽  
Pulse Width ◽  
Fiber Lasers ◽  
Peak Power ◽  
Wave Model ◽  
Core Size ◽  
The Core ◽  
Q Switching ◽  
Output Characteristics

All-fiber passively Q-switched lasers were demonstrated using ytterbium-doped double cladding fiber (YDF) as an active medium. The laser was pumped by three 25W, 975nm fiber coupled diodes and Q-switching was initiated when the amplified spontaneous emission generated in the core of the gain fiber bleached the saturable absorber (SA). A piece of samarium-doped fiber was used as SA in first configuration and pulses with 68μJ pulse energy and 210ns pulse width were obtained. In second configuration, a piece of ytterbium-doped fiber with much smaller core size was used as SA to produce pulse energy of 86μJ. The last configuration incorporated a 9m-long YDF as gain fiber. The far end from pump was acting as SA in this case and pulses with 82μJ pulse energy and 148ns pulse width were observed. The peak power was estimated at 554W. Traveling wave model was implemented to numerically simulate the output characteristics versus pump power.

Solution-Responsive Particle Size Adaptivity in Lagrangian Vortex Particle Methods

2021 ◽  
Author(s):  
Mark J. Stock ◽  
Adrin Gharakhani
Keyword(s):  
Particle Size ◽  
Particle Method ◽  
Adaptive Method ◽  
Particle Methods ◽  
Core Size ◽  
Large Particle Size ◽  
The Core ◽  
Vortex Particle Method ◽  
Computational Resources ◽  
Vortex Particle

Abstract In order to minimize the computational resources necessary for a given level of accuracy in a Lagrangian Vortex Particle Method, a novel particle core size adaptivity scheme has been created. The method adapts locally to the solution while preventing large particle size gradients, and optionally adapts globally to focus effort on important regions. It is implemented in the diffusion solver, which uses the Vorticity Redistribution Method, by allowing and accounting for variations in the core radius of participating particles. We demonstrate the effectiveness of this new method on the diffusion of a δ-function and impulsively started flow over a circular cylinder at Re = 9,500. In each case, the adaptive method provides solutions with marginal loss of accuracy but with substantially fewer computational elements.

Core@shell nanostructured Au-d@NimPtm for electrochemical oxygen reduction reaction: effect of the core size and shell thickness

2019 ◽  
Vol 9 (17) ◽  
pp. 4668-4677 ◽  
Author(s):  
Min Zhang ◽  
Shu Miao ◽  
Bo-Qing Xu
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Shell Thickness ◽  
Reduction Reaction ◽  
Core Shell ◽  
Core Size ◽  
The Core ◽  
Electrocatalytic Performance ◽  
Electrochemical Oxygen

Au-d@NimPtm nanostructures are studied to address the effects of the Au-core size (d) and NiPt-shell thickness (m) on the electrocatalytic performance of Pt for the ORR.

scholarly journals Clouds, cores, and stars in the nearest molecular complexes

1991 ◽  
Vol 147 ◽  
pp. 221-228
Author(s):  
P. C. Myers
Keyword(s):  
Column Density ◽  
Velocity Dispersion ◽  
Molecular Complexes ◽  
Star Cluster ◽  
The Sun ◽  
Core Size ◽  
Core Mass ◽  
The Core ◽  
Internal Motions ◽  
Over Time

The properties and structure of six molecular complexes within 500 pc of the Sun are described and compared. They are generally organized into elongated filaments which appear connected to less elongated, more massive clouds. Their prominent star clusters tend to be located in the massive clouds rather than in the filaments. The complexes have similar structure, but big differences in scale, from a few pc to some 30 pc. They show a pattern of regional virial equilibrium, where the massive, centrally located clouds are close to virial equilibrium, while the less massive filaments and other small clouds have too little mass to bind their observed internal motions. Complexes can be ranked according to increasing size, mass, core mass, and the mass and number of the associated stars: they range from Lupus to Taurus to Ophiuchus to Perseus to Orion B to Orion A. The cores in nearby complexes tend to have maps which are elongated, rather than round. The core size, velocity dispersion, and column density of most cores are consistent with virial equilibrium. Cores in Orion tend to exceed cores in Taurus in their line width, size, temperature, mass, and in the mass of the associated star, if any. Stars in Orion tend to be more numerous and more massive than in Taurus, while those in Taurus tend to be more numerous and more massive than in Lupus. The mass of a core tends to increase with the mass of the cloud where it is found, with the mass of the star cluster with which it is associated, and with its proximity to a star cluster. These properties suggest that complexes and their constituent cores and clusters develop together over time, perhaps according to the depth of the gravitational well of the complex.

scholarly journals Indium Phosphide-Based Semiconductor Nanocrystals and Their Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Paul Mushonga ◽  
Martin O. Onani ◽  
Abram M. Madiehe ◽  
Mervin Meyer
Keyword(s):  
Indium Phosphide ◽  
Surface Passivation ◽  
Semiconductor Nanocrystals ◽  
Core Size ◽  
The Core ◽  
Colloidal Semiconductor Nanocrystals ◽  
Biological Studies ◽  
Fluorescent Materials ◽  
Different Types ◽  
Heating Up

Semiconductor nanocrystals or quantum dots (QDs) are nanometer-sized fluorescent materials with optical properties that can be fine-tuned by varying the core size or growing a shell around the core. They have recently found wide use in the biological field which has further enhanced their importance. This review focuses on the synthesis of indium phosphide (InP) colloidal semiconductor nanocrystals. The two synthetic techniques, namely, the hot-injection and heating-up methods are discussed. Different types of the InP-based QDs involving their use as core, core/shell, alloyed, and doped systems are reviewed. The use of inorganic shells for surface passivation is also highlighted. The paper is concluded by some highlights of the applications of these systems in biological studies.

scholarly journals CADOR “Core with Adding DOppleR effect” concept application to sodium fast reactors

2019 ◽  
Vol 5 ◽  
pp. 1
Author(s):  
Alain Zaetta ◽  
Bruno Fontaine ◽  
Pierre Sciora ◽  
Romain Lavastre ◽  
Robert Jacqmin ◽  
...  
Keyword(s):  
Mechanical Energy ◽  
Core Size ◽  
Fuel Temperature ◽  
Fast Reactors ◽  
The Core ◽  
Loss Of Coolant ◽  
Neutron Moderator ◽  
Concept Application ◽  
Sodium Fast Reactors ◽  
Reactivity Insertion

Generation-IV sodium fast reactors (SFR) will only become acceptable and accepted if they can safely prevent or accommodate reactivity insertion accidents that could lead to the release of large quantities of mechanical energy, in excess of the reactor containment's capacity. The CADOR approach based on reinforced Doppler reactivity feedback is shown to be an attractive means of effectively preventing such reactivity insertion accidents. The accrued Doppler feedback is achieved by combining two effects: (i) introducing a neutron moderator material in the core so as to soften the neutron spectrum; and (ii) lowering the fuel temperature in nominal conditions so as to increase the margin to fuel melting. This study shows that, by applying this CADOR approach to a Generation-IV oxide-fuelled SFR, the resulting core can be made inherently resistant to reactivity insertion accidents, while also having increased resistance to loss-of-coolant accidents. These preliminary results have to be confirmed and completed to meet multiple safety objectives. In particular, some margin gains have to be found to guarantee against the risk of sodium boiling during unprotected loss of supply power accidents. The main drawback of the CADOR concept is a drastically reduced core power density compared to conventional designs. This has a large impact on core size and other parameters.

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