Mixture Of Nd Research Articles

Химический синтез наноструктурированного магнитотвердого сплава системы Nd-Fe-B

Hard magnetic nanopowders of the Nd15Fe78B7 alloy were synthesized from mixtures of Nd, Fe and Fe-B oxides with CaH2 in a hydrogen atmosphere at 800 °C by a reduction-diffusion process. Nd, Fe, Fe-B oxides were synthesized by chemical deposition. The resulting particles had a granular shape with an average size: Nd2O3 — 50 nm, Fe2O3 — 95 nm, Fe3BO6 — 57 nm. The particle size of the Nd15Fe78B7 alloy was 45–140 nm. It is shown that the proposed method is suitable for obtaining nanopowders of hard magnetic alloys of the Nd-Fe-B system.

Hair Removal With Blended 755/1064 nm Laser Energy.

The 1064 nm wavelength is optimized for dark skin, but within the range of available fluences for commercially available 1064 nm devices, may not provide effective treatment for lighter hair. The 755 nm alexandrite wavelength can treat a full range of hair colors but is not ideal for darker skin. The hypothesis is that a new laser system capable of emitting 755/1064 nm wavelengths simultaneously allows for safer, effective, and less painful hair reduction over a range of skin and hair types. We completed treatment in 36 patients in this institutional review board approved prospective randomized study. Ages ranged from 20 to 55 and the distribution of skin types was: I (14% of patients), II (50% of patients), III (18% of patients), IV (18% of patients). Areas included the axilla and lower extremity. A prototype laser system emitted 755/1064 nm simultaneously. The spot size was 12 mm and the pulse duration was 3 milliseconds. The percentage of each wavelength in the mixture varied from 0% to 100%. Total radiant exposure ranged from 20 to 50 J/cm2 . Test spots were performed with escalating doses of light for each category (alexandrite alone, Nd YAG alone, and blended). Patients returned within 1 week for evaluation of side effects. The highest fluence without side effects for each category was then applied in two sessions 1 month apart. Final hair counts were performed 2 months after the final treatment. Optimal light doses (in J/cm2 ) for the range of skin types were as follows: for alexandrite alone, YAG alone, and blended. (Skin type I) 40, 70, 40-10; (II) 40, 70, 40-10; (III) 34, 60, 30-20; (IV) 26, 60, 20-30; (V) 18, 50, 14-36. After 2 months, there was greater than 50% hair reduction in 40%, 24%, and 60% of subjects on the lower extremity for the alexandrite, Nd YAG, and blended groups, respectively, and 20%, 25%, and 24% for the axilla. Our data show that for "challenging" cases, that is, darker skin types or tanned skin with lighter hairs, a 70/30 mixture of Nd:YAG and alexandrite wavelengths tended to produce the greatest hair reduction andleast epidermal compromise while maintaining a lower pain level than Nd YAG alone. Modeling and data suggest that 755/1064 nm mixture is useful in lighter hair removal treatment for darker skin types. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

Chemical synthesis and research nanopowder of magnetic hard alloy Nd15Fe78B7

Hard magnetic nanopowders of the Nd15Fe78B7 alloy were synthesized by the reduction-diffusion reaction of a stoichiometric mixture of Nd, Fe, and Fe-B oxides with CaH2 in a hydrogen atmosphere at 800 ° C. Nd, Fe, Fe-B oxides were obtained by precipitation and had the form of granules with an average particle size of neodymium oxide - 50 nm, iron oxide - 95 nm, iron borate - 57 nm. The particle size of the Nd15Fe78B7 alloy was 45-140 nm. It is shown that the proposed method is suitable for obtaining nanopowders of hard magnetic alloys of the Nd-Fe-B system.

Effect of binary mixture of Nd–Zn ions on the electrical, structural and dielectric behavior of calcium-barium M-type hexaferrite nanoparticles

This study reports the synthesis and characterization of Nd–Zn-doped nanocrystalline Ca0.5Ba0.5-xNdxZnyFe12-yO19 (x = 0.00–0.10; y = 0.00–1.00) hexaferrites prepared by sol–gel auto combustion method. Doping of the binary mixture of Nd–Zn enhances the electrical and structural properties of Ca0.5Ba0.5-xNdxZnyFe12-yO19 hexaferrite nanoparticles. The required annealing temperature was obtained on the basis of TG/DTA analysis. The results of X-ray diffraction patterns revealed that dopant contents are inversely related to lattice parameters. The average nanocrystalline size lies in the range from 16 to 29 nm. The DC electrical resistivity decreased, whereas the drift mobility was increased by increasing doping of Nd–Zn. Maxwell–Wagner and Koop’s models were used to explain the dielectric constant and dielectric loss versus frequency. Nd–Zn doping favored the decrease in dielectric losses to a large extent, so the barium hexaferrite along with these dopants is very useful for high frequency applications. AC conductivity at low frequencies explained the grain boundary behavior; however, the dispersion at high frequency may be attributed to the conductivity of grains. The M–H loop indicated that the coercivity changed as a result of increase in grain size and saturation magnetization was increased as a result of strong and magnetic cations distribution on interstitial sites.

KARAKTERISASI BESARAN MAGNET PERMANEN DARI HASIL CAMPURAN NdFeB DAN SERBUK EPOXY RESIN

The bonded permanent magnet Nd 2 Fe 14 B has been made using raw materials Nd-Fe-B powder mixed withadhesive epoxy resin . Permanent magnets can be applied as a component of small DC motors and car parts.NdFeB composition variation on epoxy resins are made with the ratio of 93 : 7, 95 : 5, 90 : 10, 80 : 20, 70 : 30, 60: 40, 50 : 50, (% weight). Raw material NdFeB was made from the mixture of Nd, Fe and B with atomic ratio 2 :14 : 1 by using mechanical alloying technique. The blend of NdFeB and epoxy resin has been done in the vacuumbox . Sample test was prepared by compression with hydraulic press pressure 100kg/cm 2 within 2 minutes. Heattreatment in the oven with a temperature of 180 O C for 4 hours. The sample test was made in cylindrical shape witha diameter of 2-3 cm and thickness of 0.4 to 0.9 cm. The measurement of density vs. Histerisis has been recorded.The results show that the bonded NdFeB permanent magnets achieve optimum conditions in comparison NdFeB97% and 3% epoxy with the density = 4.49 g/cm3 and remanansi (Br) = 5.32 kG, HcJ = 7.936 kOe and (BH) max= 5.75 MGOe.

Seed dormancy and dormancy-breaking conditions of 12 West African woody species with high reforestation potential in the forest-savanna ecotone of Côte d'Ivoire

Information on the regeneration ecology of native woody species of the forest-savanna ecotone of West Africa is scarce, which is a major impediment to their optimal utilization in large-scale restoration programmes. The scattered information that is available for some of these species reveals that freshly matured seed are dormant. However, environmental heterogeneity among different habitats may results in inter-population seed dormancy variation. Thus, our objective was to re-examine the dormancy of 12 species from the forest-savanna ecotone that have been targeted for reforestation. Specifically, we aimed to examine the water-permeability of the seeds and explore the effectiveness of acid scarification and heat treatment to alleviate dormancy. Four species belonging to families other than Fabaceae and Malvaceae had water-permeable seeds. Two of them had nondormant (ND) seeds, and seeds of the other two species had a mixture of ND and other kinds of dormancy (possibly physiological dormancy, PD). Most species of Fabaceae and Malvaceae had water-impermeable seeds. All seeds of three species had physical dormant (PY), and some seeds of the remaining species had PY, while others were ND or had PD. Acid-scarification was effective in breaking PY and in augmenting imbibition and germination of non-PY seeds, while heat treatment was moderately effective in breaking dormancy. In general, acid scarification for 1-30 minutes and heat treatment for one hour at 55-75°C were optimal to enhance seed germination, depending on species. The present study has wide practical implications for park conservationists and restoration ecologists interested in producing bulk quantities of high-quality planting stocks of native woody species for large-scale restoration programmes.

Sustainable Development of Corrosion Inhibitors from Electronic Scrap: Synthesis and Electrochemical Performance

Due to its high content of rare earths, the use of permanent magnets can be a sustainable alternative for the synthesis of environmentally friendly corrosion inhibitors in order to replace the use of highly toxic inhibitors, as well as the use of rare earth salts of high purity and high cost. In this study, the recovery of rare earths from permanent magnet wastes and their synthesis to chloride salts were carried out. Rare earth chlorides were evaluated as corrosion inhibitors by electrochemical techniques on API X70 steel in a 3.5% NaCl solution. Both anodic and cathodic polarization curves were made, and measurements of both open-circuit potential, linear polarization resistance, and electrochemical impedance were made. Results show that the inhibitor synthesized is a mixture of Nd and Pr chloride. Its performance as a corrosion inhibitor is superior to that of high purity Nd chloride (analytical reagent). The results show that the use of electronic scrap is a sustainable source for the synthesis of green corrosion inhibitors with low carbon footprint.

Synthesis and Structure of the Inclusion Complex {NdQ[5]K@Q[10](H₂O)₄}·4NO₃·20H₂O.

Heating a mixture of Nd(NO3)3·6H2O, KCl, Q[10] and Q[5] in HCl for 10 min affords the inclusion complex {NdQ[5]K@Q[10](H2O)4}·4NO3·20H2O. The structure of the inclusion complex has been investigated by single crystal X-ray diffraction and by X-ray Photoelectron spectroscopy (XPS).

Recovery of Dy from a Mixture of Nd, Fe, B and Dy by Electrolysis in Molten LiCl

Recovery of Dy from a Mixture of Nd, Fe, B and Dy by Electrolysis in Molten LiCl

Mechanical properties of nanodiamond and multi-walled carbon nanotubes dual-reinforced aluminum matrix composite materials

Nanodiamond (nD) and multi-walled carbon nanotubes (CNT) was used to fabricate reinforced pure aluminum (Al) matrix composites by mechanical ball milling and hot-pressing. Pure Al bulk and each single nanoparticle (nD or CNT) reinforced composites was also fabricated for comparison. Micro-Vickers hardness was measured for single (nD or CNT) and dual nanoparticle (mixture of nD and CNT)-reinforced Al matrix composites and showed maximum values that were approximately six times higher than those of pure Al bulk. Four-point bending behaviors were also discussed and the dual nanoparticles-reinforced Al matrix composites showed highest value of the flexural strength (about 760MPa). The fracture surfaces that resulted from the bending test were also observed. Moreover, the crystallite size and lattice strain of the Al particles in the composites were described by the Scherrer equation.

Growth of NdFeAsO Films by a Combination of Metal–Organic Chemical Vapor Deposition and Arsenic Diffusion Processes

NdFeAsO films have been grown by a two-step method. First, precursor films that contain a mixture of Nd and Fe oxides were grown by metal-organic chemical vapor deposition. Afterward, the arsenic is incorporated during annealing of these precursor films in the presence of a NdFeAsO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.75</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.25</sub> pellet. The X-ray diffraction and the scanning electron microscopy show that the formation of the quaternary NdFeAsO phase is prevented by the stability of the rare-earth oxides and rare-earth oxyfluorides and that it is synthesized only if the annealing temperature is higher than 1050 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C. Although the pellet creates a reaction atmosphere to synthesize the superconducting phase, the fluorine is not incorporated into the quaternary NdFeAsO phase.

Magnetization reversal processes in bonded magnets made from a mixture of Nd–(Fe,Co)–B and strontium ferrite powders

Isotropic epoxy-resin bonded magnets composed of different amounts of Magnequench MQP-B and strontium ferrite powders have been prepared using a compression molding technique. The magnetic parameters for magnets with different amounts of strontium ferrite and magnetization reversal processes have been studied by the measurement of the initial magnetization curves, the major hysteresis loops measured at a field up to 14T and sets of recoil loops. The enhancement of μ0MR and μ0HC is observed in comparison with the calculated values. From the recoil loops the field dependences of the reversible, irreversible and total magnetization components and the differential susceptibilities were derived. From the dependence of the irreversible magnetization component versus an applied field it was deduced that the main mechanism of magnetization reversal process is the pinning of domain walls in MQP-B and strontium ferrite grains. The interactions between the magnetic particles and grains have been examined by the analysis of the δM plot. The δM behavior of magnets with ferrite has been interpreted as being composed of magnetizing exchange coupling and demagnetizing dipolar interactions.

Dynamic Interaction of the Escherichia coli Cell Division ZipA and FtsZ Proteins Evidenced in Nanodiscs

The full-length ZipA protein from Escherichia coli, one of the essential components of the division proto-ring that provides membrane tethering to the septation FtsZ protein, has been incorporated in single copy into nanodiscs formed by a membrane scaffold protein encircling an E. coli phospholipid mixture. This is an acellular system that reproduces the assembly of part of the cell division components. ZipA contained in nanodiscs (Nd-ZipA) retains the ability to interact with FtsZ oligomers and with FtsZ polymers. Interactions with FtsZ occur at similar strengths as those involved in the binding of the soluble form of ZipA, lacking the transmembrane region, suggesting that the transmembrane region of ZipA has little influence on the formation of the ZipA·FtsZ complex. Peptides containing partial sequences of the C terminus of FtsZ compete with FtsZ polymers for binding to Nd-ZipA. The affinity of Nd-ZipA for the FtsZ polymer formed with GTP or GMPCPP (a slowly hydrolyzable analog of GTP) is moderate (micromolar range) and of similar magnitude as for FtsZ-GDP oligomers. Polymerization does not stabilize the binding of FtsZ to ZipA. This supports the role of ZipA as a passive anchoring device for the proto-ring with little implication, if any, in the regulation of its assembly. Furthermore, it indicates that the tethering of FtsZ to the membrane shows sufficient plasticity to allow for its release from noncentral regions of the cytoplasmic membrane and its subsequent relocation to midcell when demanded by the assembly of a division ring.

Corrosion mechanism of Mo/Nd 16Fe 71B 13/Mo film in a simulated marine atmosphere

This study describes the corrosion mechanism of Mo/Nd 16Fe 71B 13/Mo film induced by sodium chloride particles in 80% relative humidity (RH) environment. The deliquescence of sodium chloride particles on the Mo/Nd 16Fe 71B 13/Mo film caused the step by step attacks. Initial loosening of the Mo layer allows permeation of electrolyte into Nd–Fe–B layer, resulting in cavitations of electrolyte and subsequent film failure. The second failure step involves corrosion of Nd element in the Nd–Fe–B layer, with Fe element remaining beneath the corrosion product. Corrosion of Fe constitutes the third-step failure, forming a mixture of Nd and Fe corrosion product.

Could binary mixture of Nd–Ni ions control the electrical behavior of strontium–barium M-type hexaferrite nanoparticles?

Cationic substitution in M-type hexaferrites is considered to be an important tool for modification of their electrical properties. This work is part of our comprehensive study on the synthesis and characterization of Nd–Ni doped strontium–barium hexaferrite nanomaterials of nominal composition Sr 0.5Ba 0.5− x Nd x Fe 12− y Ni y O 19 ( x = 0.00–0.10; y = 0.00–1.00). Doping with this binary mixture modulates the physical and electrical properties of strontium–barium hexaferrite nanoparticles. Structural and electrical properties of the co-precipitated ferrites are investigated using state-of-the-art techniques. The results of X-ray diffraction analysis reveal that the lattice parameters and cell volume are inversely related to the dopant content. Temperature dependent DC-electrical resistivity measurements infer that resistivity of strontium–barium hexaferrites decreases from 1.8 × 10 10 to 2.0 × 10 8 Ω cm whereas the drift mobility, dielectric constant and dielectric loss tangent are directly related to the Nd–Ni content. The results of the study demonstrate a relationship between the modulation of electrical properties of substituted ferrites and nature of cations and their lattice site occupancy.

Single-Molecule Atomic Force Spectroscopy Reveals that DnaD Forms Scaffolds and Enhances Duplex Melting

The Bacillus subtilis DnaD is an essential DNA-binding protein implicated in replication and DNA remodeling. Using single-molecule atomic force spectroscopy, we have studied the interaction of DnaD and its domains with DNA. Our data reveal that binding of DnaD to immobilized single molecules of duplex DNA causes a marked reduction in the ‘end-to-end’ distance of the DNA in a concentration-dependent manner, consistent with previously reported DnaD-induced looping by scaffold formation. Native DnaD enhances partial melting of the DNA strands. The C-terminal domain (Cd) of DnaD binds to DNA and enhances partial duplex melting but does not cause DNA looping. The Cd-mediated melting is not as efficient as that caused by native DnaD. The N-terminal domain (Nd) does not affect significantly the DNA. A mixture of Nd and Cd fails to recreate the DNA looping effect of native DnaD but produces exactly the same effects as Cd on its own, consistent with the previously reported failure of the separated domains to form DNA-interacting scaffolds.

Preparation for exchange-coupled permanent magnetic composite between α-Fe (soft) and Nd2Fe14B (hard)

Abstract Soft magnetic α-Fe nanoparticles were prepared by a coprecipitation route and hard magnetic Nd 15 Fe 77 B 8 nanoparticles were prepared by ball milling for 20 h by using a shaker mill. A mechanical ball-mill technique was applied to build up exchange-coupled nanoparticles. A mixture of Nd 2 Fe 14 B and α-Fe nanoparticles in a stainless steel boat was milled for 2 h and annealed in a vacuum furnace under vacuum (∼10 −5 Torr) at 650 °C for 30 min. The crystal structure of the nanoparticles was confirmed by using X-ray powder diffraction (XRD). The surface morphology was identified by FE-SEM. The magnetization curve was measured with a vibrating-sample magnetometer (VSM). Thermogravimetry using a microbalance with magnetic field gradient positioned below the sample was used for the measurement of a thermomagnetic analysis (TMA) curve showing the downward magnetic force versus temperature.

Features of the HDDR process in R–Fe–B ferromagnetic alloys (R is a mixture of Nd, Pr, Ce, La, Dy and others)

Features of the conventional hydrogenation, disproportionation, desorption, recombination (HDDR) and solid-HDDR processes in some R–Fe–B (R is a mixture of Nd, Pr, Ce, La, Dy) ferromagnetic alloys were studied in the temperature range 20–990 °C and pressure range from 1×10 −3 Pa to 0.1 MPa. This was carried out by means of differential thermal analysis (DTA), X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) methods. The hydride of the initial phase is formed by heating to 115 °C. The disproportionation of the alloys occurs in the temperature range from 320 to 800 °C. Φ-phase constitutes the base of the initial alloys. Among the disproportionation products, R-hydride, α-Fe and two borides (Fe 2B and R 1.1Fe 4B 4) were revealed. The initial phase in all the alloys is recovered after heating in vacuum to a temperature of 990 °C. Full hydrogen desorption occurs in two temperature ranges with the peaks at 200–320 and 630–715 °C.

Reinvestigation of phase relations around the oxyapatite phase in the Nd 2O 3–SiO 2 system

Phase relations around the oxyapatite phase in the Nd 2O 3–SiO 2 system have been investigated by means of a slow cooling floating zone (SCFZ) method and solid-state reactions. The results on SCFZ proved that the oxyapatite phase melts congruently at the composition of Nd 2O 3:SiO 2=7:9, corresponding to Nd 9.33(SiO 4) 6O 2. The 2:3 phase (Nd 8(SiO 4) 6), which had been believed to have an apatite structure and to melt congruently, does not exist and consists of a mixture of Nd 9.33(SiO 4) 6O 2 and Nd 2Si 2O 7 phases. The solid-state reaction revealed that a solid solution region of the oxyapatite phase is extremely narrow or does not exist below 1650°C.

Mechanochemical effects on synthesis of Rhabdophane-type neodymium and cerium phosphates

Mechanochemical effects were investigated in the mixture of a rare earth compound (Nd(NO3)3·6H2O, NdCl3·6H2O, Nd2(CO3)3·8H2O, Ce(NO3)3·6H2O, CeCl3·7H2O, or Ce2(CO3)3·8H2O) and (NH4)2HPO4. These mixtures were ground and then heated. These ground mixtures and thermal products were characterized by X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), thermogravimetry–differential thermal analyses (TG–DTA), and adsorption of nitrogen. By grinding, Rhabdophane-type rare earth (Nd or Ce) phosphate was formed in the mixture of Nd(NO3)3·6H2O–(NH4)2HPO4 or Ce(NO3)3·6H2O–(NH4)2HPO4. By mechanical treatment, Rhabdophane-type neodymium phosphate was formed at lower temperature in the mixture of NdCl3·6H2O–(NH4)2HPO4. The mixture of CeCl3·7H2O–(NH4)2HPO4 indicated XRD peaks of CeO2 by heating, whereas ground mixtures transformed to Rhabdophane-type cerium phosphate. Specific surface areas of Rhabdophane-type neodymium and cerium phosphates verified from 0.1 to 120m2/g depending on various synthetic conditions. Rhabdophane-type neodymium and cerium phosphates which had large specific surface area were obtained by grinding with ethanol and then heating.