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1.
Nanotechnology ; 33(21)2022 Feb 28.
Article in English | MEDLINE | ID: mdl-35147526

ABSTRACT

The growing gap between the volume of digital data being created and the extent of available storage capacities stimulates intensive research into surface-supported, well-ordered array of atom-sized magnets that represents the ultimate limit of magnetic data storage. Anchoring transition-metal heterodimers in vacancy defects in the graphene lattice has been identified as a vivid strategy to achieve large magnetic anisotropy energy (MAE) up to 80 meV with an easy axis aligned along the dimer bond. In this paper we have made a significant leap forward finding out MAE of 119 meV for an OsPt dimer and 170 meV for an OsPd dimer bound to a single nitrogen-decorated vacancy defect. The system with the highest MAE and with the theoretical storage density of ∼490 Tb·inch-2pushes the current limit of theoretical blocking temperature in graphene-supported transition-metal dimers from ∼20 to ∼44 K assuming the relaxation time of 10 years. The mechanism of the enhanced MAE is discussed.

2.
Nanotechnology ; 2022 Feb 10.
Article in English | MEDLINE | ID: mdl-35144253

ABSTRACT

The growing gap between the volume of digital data being created and the extent of available storage capacities stimulates intensive research into surface-supported, well-ordered array of atom-sized magnets that represents the ultimate limit of magnetic data storage. Anchoring transition metal heterodimers in vacancy defects in the graphene lattice has been identified as a vivid strategy to achieve large magnetic anisotropy energy (MAE) up to 80 meV with an easy axis aligned along the dimer bond. In this paper we have made a significant leap forward finding out MAE of 119 meV for an OsPt dimer and 170 meV for an OsPd dimer bound to a single nitrogen-decorated vacancy defect. The system with the highest MAE and with the theoretical storage density of 490 Tb inch-2pushes the current limit of theoretical blocking temperature in graphene-supported transition-metal dimers from ~20 K to ~44 K assuming the relaxation time of 10 years. The mechanism of the enhanced MAE is discussed.

3.
Nanotechnology ; 32(23)2021 Mar 19.
Article in English | MEDLINE | ID: mdl-33626515

ABSTRACT

Single-atom magnets represent the ultimate limit of magnetic data storage. The identification of substrates that anchor atom-sized magnets firmly and, thus, prevent their diffusion and large magnetic anisotropy has been at the centre of intense research efforts for a long time. Using density functional theory we show the binding of transition metal (TM) atoms in defect sites in the graphene lattice: single vacancy and double vacancy, both pristine and decorated by pyridinic nitrogen atoms, are energetically more favourable than away from the centre of defects, which could be used for engineering the position of TMs with atomic precision. Relativistic calculations revealed magnetic anisotropy energy (MAE) of ∼10 meV for Ir@NSV with an easy axis parallel to the graphene plane. MAE can be remarkably boosted to 50 meV for OsIr@NSV with the easy axis perpendicular to the graphene plane, which paves the way to the storage density of ∼490 Tb/inch2with the blocking temperature of 14 K assuming the relaxation time of 10 years. Magnetic anisotropy is discussed based on the relativistic electronic structures. The influence of an orbital-dependent on-site Coulomb repulsionUand a non-local correlation functional optB86b-vdW on MAE is also discussed.

4.
Polymers (Basel) ; 10(6)2018 Jun 09.
Article in English | MEDLINE | ID: mdl-30966675

ABSTRACT

This article deals with the study of the utilisation of irradiated HDPE products after their end-of-life cycle. Today, polymer waste processing is a matter of evermore intensive discussion. Common thermoplastic waste recycling-especially in the case of wastes with a defined composition-is generally well-known-and frequently used. On the contrary, processing cross-linked plastics is impossible to do in the same way as with virgin thermoplastics-mainly due to the impossibility of remelting them. The possibility of using waste in the form of grit or a powder, made from cross-linked High Density PolyEthylene (rHDPEx) products, after their end-of-life cycle, as a filler for virgin Low Density PolyEthylene (LDPE) was tested in a matrix. It was found that both the mechanical behaviour and processability of new composites with an LDPE matrix, with rHDPEx as a filler, depend-to a high degree-on the amount of the filler. The composite can be processed up to 60% of the filler content. The Polymer Mixture Fluidity dropped significantly, in line with the amount of filler, while the mechanical properties, on the other hand, predominantly grew with the increasing amount of rHDPEx.

5.
Polymers (Basel) ; 10(12)2018 Dec 08.
Article in English | MEDLINE | ID: mdl-30961286

ABSTRACT

This article discusses the possibilities of using radiation cross-linked high density polyethylene (HDPEx) acting as a filler in the original high density polyethylene (HDPE) matrix. The newly created composite is one of the possible answers to questions relating to the processing of radiation cross-linked thermoplastics. Radiation cross-linked networking is-nowadays, a commonly used technology that can significantly modify the properties of many types of thermoplastics. This paper describes the influence of the concentration of filler, in the form of grit or powder obtained by the grinding/milling of products/industrial waste from radiation cross-linked high density polyethylene (rHDPEx) on the mechanical and processing properties and the composite structure. It was determined that, by varying the concentration of the filler, it is possible to influence the mechanical behaviour of the composite. The mechanical properties of the new composite-measured at room temperature, are generally comparable or better than the same properties of the original thermoplastic. This creates very good assumptions for the effective and economically acceptable, processing of high density polyethylene (rHDPEx) waste. Its processability however, is limited; it can be processed by injection moulding up to 60 wt %.

6.
Vet Parasitol ; 206(3-4): 328-32, 2014 Dec 15.
Article in English | MEDLINE | ID: mdl-25458566

ABSTRACT

Nine ponies, aged 12 months at the time of infection, were randomly allocated to one of three groups. Each pony was infected with 30,000 infective cyathostome larvae stored 4 weeks under the natural environmental conditions of the Czech Republic. Horses of Group A were infected with larvae conditioned from August 16 to September 12 (the first phase of the experiment). Horses of Group B were inoculated with larvae conditioned from October 10 to November 4 (the second phase of the experiment). In the third phase, horses from Group C received larvae stored under natural conditions (from 8.11 to 18.11.2011). The larvae were then kept under laboratory conditions (5 °C, the light reduction according to the nature condition). In the first and second phase of the experiment, 98.57% and 95.48% of adult nematodes were found, respectively. However, only 29.07% of adults were found in the third phase of experiment, and the proportion of arrested larvae (EL3) was 67.73%. The share of these larvae in the cecum during last phase of the experiment comprised 92.59% of all cyathostomes.


Subject(s)
Horse Diseases/parasitology , Strongyle Infections, Equine/parasitology , Strongyloidea/growth & development , Animals , Cecum/parasitology , Czech Republic , Horses , Larva , Random Allocation
7.
Int J Food Microbiol ; 182-183: 37-43, 2014 Jul 16.
Article in English | MEDLINE | ID: mdl-24859188

ABSTRACT

Highly undesirable microbial contaminants of processed cheese are endospore-forming bacteria of the genera Bacillus and Clostridium. Survival of Bacillus subtilis, B. cereus, Clostridium butyricum and C. sporogenes was examined in model processed cheese samples supplemented with monoacylglycerols. In processed cheese samples, monoacylglycerols of undecanoic, undecenoic, lauric and adamantane-1-carboxylic acid at concentration of 0.15% w/w prevented the growth and multiplication of both Bacillus species throughout the storage period. The two species of Clostridium were less affected by monoacylglycerols in processed cheese samples and only partial inhibition was observed. The effect of milk fat content on microbial survival in processed cheese was also evaluated. The growth of Bacillus sp. was affected by the fat level of processed cheese while population levels of Clostridium sp. did not differ in processed cheese samples with 30, 40 and 50% fat in dry matter.


Subject(s)
Anti-Infective Agents/pharmacology , Bacillus/drug effects , Cheese/microbiology , Clostridium/drug effects , Food Microbiology , Monoglycerides/pharmacology , Clostridium/growth & development , Fats/metabolism , Fats/pharmacology , Food Additives/pharmacology
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