•Ni-doped branched ZnO nanowires were grown using three-step vapor phase reaction.•Gas response was significantly enhanced by the formation of Ni-doped ZnO branches.•Doped Ni acted as catalyst for ...the selective detection of p-xylene.•A novel method to grow catalyst-doped hierarchical ZnO nanowires is suggested.
Branched ZnO nanowires (NWs) doped with Ni were grown by a three-step vapor phase method for the sensitive and selective detection of p-xylene. ZnO NWs were directly grown on sensor substrates with Au electrodes, which were transformed into NiO NWs by the thermal evaporation of NiCl2 powder at 700°C. ZnO branches doped with Ni were grown from NiO NWs by the thermal evaporation of Zn metal powder at 500°C. The stem NiO NWs played the role of catalyst for the growth of ZnO branches through vapor–liquid–solid mechanism. The Ni-doped branched ZnO NWs showed enhanced gas response (S=resistance ratio) to methyl benzenes, especially to 5ppm p-xylene (S=42.44) at 400°C. This value is 1.7 and 2.5 times higher than the responses to 5ppm toluene (S=25.73) and C2H5OH (S=16.72), respectively, and significantly higher than the cross-responses to other interfering gases such as benzene, HCHO, trimethylamine, H2, and CO. The selective detection of xylene was attributed to the catalytic role of the Ni component. This novel method to form catalyst-doped hierarchical ZnO NWs provides a promising approach to accomplish superior gas sensing characteristics by the synergetic combination of enhanced chemiresistive variation due to the increased number of branch-to-branch Schottky barrier contacts and the catalytic function of the Ni dopant.
Aqueous zinc ion batteries (ZIBs) are promising energy storage devices due to the high ionic conductivity of the aqueous electrolyte as well as the safety, eco‐friendliness, and low cost. Vanadium ...oxide‐based materials are attractive cathode materials for aqueous ZIBs because of their high capacity from their layered structure and multiple valences. However, it is difficult to achieve high cycle stability and rate capability due to the low electrical conductivity and trapping of diffused electrolyte cations within the crystal structure, limiting the commercialization of aqueous ZIBs. In this study, the authors propose a facile sonochemical method for controlling the interlayer of the vanadate nanofiber crystal structure using poly(3,4‐ethylene dioxythiophene) (PEDOT) to overcome the shortcomings of vanadium oxide‐based materials. In addition, the electrochemical correlation between the interplanar distance of the expanded vanadate layers by the insertion of PEDOT and the behavior of Zn2+ ions is investigated. As a result, the intercalation of the conducting polymer increases the electron pathway and extends the distance of the vanadate layers, which helps to increase the number of active sites inside the vanadate and accelerate the zinc ion intercalation/de‐intercalation process. Their findings may guide research on the next generation of ZIBs that can replace lithium ion batteries.
The controlling interlayer of the vanadate nanofiber crystal structure using intercalation of conducting polymers is fabricated via a facile sonochemical method and used as a cathode material in zinc ion batteries. Intercalated conducting polymers act as strong pillars and facilitate rapid Zn2+ ion diffusion and electron transport, resulting in reversible electrochemical reactions and high rate performance.
It is challenging to develop alloying anodes with ultrafast charging and large energy storage using bulk anode materials because of the difficulty of carrier‐ion diffusion and fragmentation of the ...active electrode material. Herein, a rational strategy is reported to design bulk Bi anodes for Na‐ion batteries that feature ultrafast charging, long cyclability, and large energy storage without using expensive nanomaterials and surface modifications. It is found that bulk Bi particles gradually transform into a porous nanostructure during cycling in a glyme‐based electrolyte, whereas the resultant structure stores Na ions by forming phases with high Na diffusivity. These features allow the anodes to exhibit unprecedented electrochemical properties; the developed Na–Bi half‐cell delivers 379 mA h g−1 (97% of that measured at 1C) at 7.7 A g−1 (20C) during 3500 cycles. It also retained 94% and 93% of the capacity measured at 1C even at extremely fast‐charging rates of 80C and 100C, respectively. The structural origins of the measured properties are verified by experiments and first‐principles calculations. The findings of this study not only broaden understanding of the underlying mechanisms of fast‐charging anodes, but also provide basic guidelines for searching battery anodes that simultaneously exhibit high capacities, fast kinetics, and long cycling stabilities.
With the difficulty in simultaneously achieving a large capacity, ultrafast charging capability, and long cycling stability in a battery anode, a bulk Bi anode is presented for Na‐ion batteries that provides a simple yet practical route to address this issue without using expensive nanoscale materials and additional complex modifications.
In two-dimensional honeycomb ferromagnets, bosonic magnon quasiparticles (spin waves) may either behave as massless Dirac fermions or form topologically protected edge states. The key ingredient ...defining their nature is the next-nearest-neighbor Dzyaloshinskii-Moriya interaction that breaks the inversion symmetry of the lattice and discriminates chirality of the associated spin-wave excitations. Using inelastic neutron scattering, we find that spin waves of the insulating honeycomb ferromagnetCrI3(TC=61K) have two distinctive bands of ferromagnetic excitations separated by a∼4meVgap at the Dirac points. These results can only be understood by considering a Heisenberg Hamiltonian with Dzyaloshinskii-Moriya interaction, thus providing experimental evidence that spin waves inCrI3can have robust topological properties potentially useful for dissipationless spintronic applications.
A quantum spin liquid is a state of matter where unpaired electrons’ spins, although entangled, do not show magnetic order even at the zero temperature. The realization of a quantum spin liquid is a ...long-sought goal in condensed-matter physics. Although neutron scattering experiments on the two-dimensional spin-1/2 kagome lattice ZnCu3(OD)6Cl2 and triangular lattice YbMgGaO4 have found evidence for the hallmark of a quantum spin liquid at very low temperature (a continuum of magnetic excitations), the presence of magnetic and non-magnetic site chemical disorder complicates the interpretation of the data. Recently, the three-dimensional Ce3+ pyrochlore lattice Ce2Sn2O7 has been suggested as a clean, effective spin-1/2 quantum spin liquid candidate, but evidence of a spin excitation continuum is still missing. Here, we use thermodynamic, muon spin relaxation and neutron scattering experiments on single crystals of Ce2Zr2O7, a compound isostructural to Ce2Sn2O7, to demonstrate the absence of magnetic ordering and the presence of a spin excitation continuum at 35 mK. With no evidence of oxygen deficiency and magnetic/non-magnetic ion disorder seen by neutron diffraction and diffuse scattering measurements, Ce2Zr2O7 may be a three-dimensional pyrochlore lattice quantum spin liquid material with minimum magnetic and non-magnetic chemical disorder.
Although many studies have demonstrated the excellent potential of hard carbon as an anode in sodium ion batteries, the contribution of its active sites to the capacities of the sloping and plateau ...voltage regions is not yet clear. Herein, systematical investigation of the relationship between the active sites and sodium ion (Na+) storage in the sloping and plateau voltage regions was presented. In light of the physicochemical properties of the lignin-derived hard carbon (graphitization degree, interlayer spacing, micropore size distribution, and specific surface area), the results of Na+ ion diffusivity, and the change in these properties during Na+ ion insertion/extraction (as characterized by ex situ techniques), new mechanistic insights into Na+ ion storage were proposed. At the beginning of the sodiation process, Na+ ions were adsorbed on defect/edge sites; then partial micropore filling occurred in the sloping region above 0.1 V. In the plateau region below 0.1 V, Na+ ions were intercalated in the graphitic layers, and further adsorption in the micropores occurred near the cutoff potential. Furthermore, sodium clustering occurred below 0.1 V owing to the high concentration of Na+ ions in the micropores.
Proposed new sodium ion storage mechanism in hard carbon derived from lignin. At the beginning of the sodiation process, Na+ ions are adsorbed on defect/edge sites; then partial micropore filling occurs in the sloping region above 0.1 V. In the plateau region below 0.1 V, Na+ ions are intercalated in the graphitic layers, and further adsorption in the micropores occurs near the cutoff potential. Furthermore, sodium clustering occurs below 0.1 V owing to the high concentration of Na+ ions in micropores. Display omitted
A gravure offset printing system composed of a roll-to-roll web-providing apparatus, a cup-type encapsulated doctoring blade, a flat gravure plate, and CCDs for line-width measurement has been ...devised for printing the electrodes of flat panel display (FPD) devices. This system may be characterized as a small experimental system capable of carrying out printing tests prior to using a huge gravure offset printing system for mass production. The conceptual design of this gravure offset printing system is focused on conducting the reliability accelerating test and on mimicking the huge mass-production printing process required for FPD parts such as plasma display panel electrodes. Using the fabricated prototype, printing experiments were repeated semi-automatically 300 times. It was found that it requires several bursts of idle printing for stabilization, that the widths of the printed pattern continue increasing little by little, and that the deviation in the width of the printed pattern increases as the number of printings is repeated. These increasing rates could constitute an index of printing reliability.
The search for topological spin excitations in recently discovered two-dimensional (2D) van der Waals (vdW) magnetic materials is important because of their potential applications in dissipationless ...spintronics. In the 2D vdW ferromagnetic (FM) honeycomb latticeCrI3(TC=61K), acoustic and optical spin waves are found to be separated by a gap at the Dirac points. The presence of such a gap is a signature of topological spin excitations if it arises from the next-nearest-neighbor (NNN) Dzyaloshinskii-Moriya (DM) or bond-angle-dependent Kitaev interactions within the Cr honeycomb lattice. Alternatively, the gap is suggested to arise from an electron correlation effect not associated with topological spin excitations. Here, we use inelastic neutron scattering to conclusively demonstrate that the Kitaev interactions and electron correlation effects cannot describe spin waves, Dirac gaps, and their in-plane magnetic field dependence. Our results support the idea that the DM interactions are the microscopic origin of the observed Dirac gap. Moreover, we find that the nearest-neighbor (NN) magnetic exchange interactions along thecaxis are antiferromagnetic (AF), and the NNN interactions are FM. Therefore, our results unveil the origin of the observedc-axis AF order in thin layers ofCrI3, firmly determine the microscopic spin interactions in bulkCrI3, and provide a new understanding of topology-driven spin excitations in 2D vdW magnets.
This study aimed to evaluate the association between sleep quality and quality of life (QoL).
This cross-sectional study included 225,541 adults (101,133 men, 124,408 women) who participated in the ...2018 Korean Community Health Survey. Multiple sociodemographic and psychosocial variables were evaluated and compared between participants with poor (n = 67,619) and good sleep quality (n = 157,922); sleep quality was subjectively determined using the Pittsburgh Sleep Quality Index (PSQI). The EuroQol five-dimension (EQ-5D) index scores were adjusted for multiple confounding factors and compared between the good and poor sleep quality groups. A logistic regression analysis was used to identify determinants of the lowest quartile of QoL.
The mean EQ-5D index scores were significantly lower in the poor sleep quality group (score 0.85) than in the good sleep quality group (score 0.92; p < 0.001). The multivariate odds ratio (OR) for the lowest quartile of the EQ-5D index scores in the poor sleep quality group versus that in the good sleep quality group was 1.95 (95% confidence interval CI, 1.89–2.00). Participants with poor sleep quality were more likely than those with good sleep quality to have some or severe problems with physical activity (OR, 1.46; 95% CI, 1.41–1.51), self-control (OR, 1.35; 95% CI, 1.29–1.42), daily activity (OR, 1.44; 95% CI, 1.39–1.50), pain (OR, 1.81; 95% CI, 1.77–1.86), and anxiety/depression (OR, 2.24; 95% CI, 2.17–2.31).
Poor sleep quality is associated with impaired QoL, particularly if some or severe problems with anxiety/depression are present.
•Poor sleep quality is associated with impaired quality of life.•Poor sleep quality were more likely to have with anxiety/depression.
The aim of this registry study was to analyze the long-term safety and effectiveness of recombinant human growth hormone (rhGH) in South Korean pediatric patients (≥2 years of age) with growth ...hormone deficiency GHD) of idiopathic or organic etiology, idiopathic short stature, Turner syndrome, small for gestational age and chronic renal failure.
The study patients were followed-up till two years after the epiphyseal closure, with visits scheduled every six months. The outcome measures included the incidence of adverse events (AEs, in particular, neoplasia, glucose intolerance and hypothyroidism), as well as height standard deviation score (Ht SDS) and annual height velocity. The results of the interim analysis of a 5-year accumulated data for 2,024 patients (7,342 patient-years, PY) are presented.
A total of 14 neoplasms were diagnosed (191/100,000 PY); 7 out of 9 malignancies were recurrent craniopharyngioma found in patients with organic GHD. Seven cases of glucose intolerance (95/100,000 PY) and 22 cases of hypothyroidism (300/100,000 PY) were detected; about half of the cases (4 and 10 cases each) were considered to be related with rhGH treatment. Most of the growth-retarded patients showed continuous improvement in Ht SDS, with the most prominent effect observed within a year of treatment initiation. The beneficial effect of rhGH on Ht SDS gain was maintained for 2-4 years.
The incidence of AEs of interest in rhGH-treated patients was low, and most of the neoplasms were benign and/or non-related to rhGH. Most patients benefited from the therapy in terms of height increment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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