bluuebunny/crossref_metadata_2025 huggingface dataset:
Dipolar Interaction Effects in the Magnetic and Magnetotransport Properties of Ordered Nanoparticle Arrays
Authors: Kechrakos D. , Trohidou K. N.
Published: April 2020

Assemblies of magnetic nanoparticles exhibit interesting physical properties arising from the competition of intraparticle dynamics and interparticle interactions. In ordered arrays of magnetic nanoparticles magnetostatic interparticle interactions introduce collective dynamics acting
competitively to random anisotropy. Basic understanding, characterization and control of dipolar interaction effects in arrays of magnetic nanoparticles is an issue of central importance. To this end, numerical simulation techniques offer an indispensable tool. We report on Monte Carlo studies
of the magnetic hysteresis and spin-dependent transport in thin films formed by ordered arrays of magnetic nanoparticles. Emphasis is given to the modifications of the single-particle behavior due to interparticle dipolar interactions as these arise in quantities of experimental interest,
such as, the magnetization, the susceptibility and the magnetoresistance. We investigate the role of the structural parameters of an array (interparticle separation, number of stacked monolayers) and the role of the internal structure of the nanoparticles (single phase, core–shell).
Dipolar interactions are responsible for anisotropic magnetic behavior between the in-plane and out-of-plane directions of the sample, which is reflected on the investigated magnetic properties (magnetization, transverse susceptibility and magnetoresistance) and the parameters of the array
(remanent magnetization, coercive field, and blocking temperature). Our numerical results are compared to existing measurements on self-assembled arrays of Fe-based and Co nanoparticles is made.
Gold Nanoparticle-Polyaniline Composite Films for Glucose Sensing
Authors: Pandey Pratibha , Singh S. P. , Arya Sunil K. , Sharma Anju , Datta Monika , Malhotra Bansi D.
Published: April 2020

Gold nanoparticles (AuNPs) have been self-assembled onto electrochemically deposited polyaniline (PANI) films on indium-tin-oxide (ITO) coated glass plates to fabricate glucose biosensor. The covalent immobilization of glucose oxidase (GOx) in the near vicinity of gold nanoparticles
has been obtained using N-ethyl-N′-(3-dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS), chemistry between amino groups of PANI and COOH groups of GOx. These AuNPs-PANI/ITO and GOx/AuNPs-PANI/ITO composite films have been characterized using Fourier transform infra red
(FTIR) and cyclic voltammetry (CV) techniques, respectively. The fast electron transfer from the modified PANI surface to electrode is indicated by the observed increase in amperometric response current of these GOx/AuNPs-PANI/ITO bioelectrodes. These GOx/AuNPs-PANI/ITO bioelectrodes exhibit
response time of 10 s, linearity from 50 to 300 mg/dl and show value of apparent Michaelis-Menten constant (Kmapp) of 2.2 mM.
Mesoporous Silicas Impregnated with Cobalt and Nickel Oxide Nanoparticles and the Growth of Carbon Nanotubes There from
Authors: Barreca D. , Blau W. J. , Dillon F. C. , Holmes J. D. , Kufazvinei C. , Morris M. A. , Spalding T. R. , Tondello E.
Published: April 2020

Metal oxide-based nanoparticles of cobalt or nickel were deposited inside the pores and on the surface of hexagonal mesoporous silicas by a direct synthesis technique using Pluronic P85 and P123 surfactants as structure directing agents with the appropriate metal phthalocyanine as a
metal precursor. Metal loadings were between 0.4–3.2 wt.%. XPS studies showed that the initial form of the metal oxide nanoparticles were [CoO] and [NiO] respectively. Samples of these materials formed from the P85 surfactant and 3.0 wt.% were used to grow carbon nanotubes (CNTs) from
acetylene feedstock in a catalytic chemical vapour deposition (CCVD) reactor at 800 °C. CNT growth appeared to be random and the CNTs had diameters ranging from <10 to >90 nm. Treatment of the metal impregnated silicas with nitric acid produced materials which, under the same CNT
growth conditions, afforded more uniform CNTs with diameters between 5–15 nm. No significant loss in mesophase ordering was seen in the TEM, PXRD or nitrogen physisorption analysis of the acid washed samples. CNTs grown with cobalt impregnated silicas formed with the P123 surfactant
had diameters in the range 15–25 nm. Raman spectroscopy of the CNT products showed the nanotubes were highly graphitised and of good quality.
Kinetics of the Nanohydrogel Flattening at a Hydrophobic Interface
Authors: Lee ImShik , Sun Haiying , Song Jingxia , Zhang Ying
Published: April 2020

Hydrophobitized polysaccharides were designed to form the self-assembled nanohydrogels (hydrogel nanoparticles) in the aqueous conditions. For improving their biocompatibilities, they were decorated with the biomembrane-mimetic 2-methacryloyloxyethy1 phosphory1choline (MPC) polymers.
The interfacial roles of the decorated membrane-mimetic nanohydrogels were investigated by choosing MPC branched choresteryl-bearing pullulan (CHP). Tapping-mode atomic force microscopy was used to study its adsorption mechanism on the hydrophobic highly oriented pyrolytic graphite (HOPG)
surface in aqueous conditions. Dynamic observation at the interfaces revealed two distinctive patterns: the immobilized nanohydrogel particles and the flatten layers. The flattening (unfolding) kinetics with and without MPC branched nanohydrogel revealed that the flattening energy was at ∼37
kBT. The flattening rate of the MPC decorated nanohydrogels was ∼1.7 times faster than that without MPC decoration, corresponding to minor reduction of the flattening activation energy.
Computational Nanomechanics and Thermal Transport in Nanotubes and Nanowires
Authors: Srivastava Deepak , Makeev Maxim A. , Menon Madhu , Osman Mohamed
Published: April 2020

Representative results of computer simulation and/or modeling studies of the nanomechanical and thermal transport properties of an individual carbon nanotube, silicon nanowire, and silicon carbide nanowire systems have been reviewed and compared with available experimental observations.
The investigated nanomechanical properties include different elastic moduli of carbon nanotubes, silicon nanowires, and silicon carbide nanowires, all obtained within their elastic limits. Moreover, atomistic mechanisms of elastic to plastic transition under external stresses and yielding
of carbon nanotubes under experimentally feasible temperature and strain rate conditions are discussed in detail. The simulation and/or modeling results on thermal properties, presented in this work, include vibrational modes, thermal conductivity and heat pulse transport through single carbon
nanotubes, and thermal conductivity of silicon nanowires.
Efficient Numerical Schemes for Electronic States in Coupled Quantum Dots
Authors: Hwang Tsung-Min , Wang Wei-Hua , Wang Weichung
Published: April 2020

Electronic states in coupled quantum dots are studied numerically and qualitatively in this article. A second-order finite volume scheme based on uniform meshes is first developed to solve the three-dimensional Schrödinger equation. The scheme is used to solve the eigenvalue problem
with more than 12million unknowns. Using these efficient numerical tools, we study quantum structure induced interactions, with emphases on the effects of dot size and space layer thickness. The numerical experiments have predicted the phenomena that envelope functions become delocalized over
two QDs and the energy levels show anticrossing behavior.
Patterned Fabrication of Single ZnO Nanorods and Measurement of Their Optoelectrical Characteristics
Authors: Yu Chun-Wei , Lai Shang-Hung , Wang Teng-Yi , Lan Ming-Der , Ho Mon-Shu
Published: April 2020

This work develops a new process of growing well ordered ZnO nanorods in large scale on the Si(111) substrate. Nanosphere lithography (NSL) was adopted to produce a matrix in an extensive area. A pattern with a controlled amount of gold was formed through the nanosphere mask. The ZnO
nanorods were then grown on a patterned Au/Si substrate through a metal catalytic vapor-liquid-solid (VLS) process. The structure and characteristics of ZnO nanorods were investigated by XRD, SEM and TEM. The hexagonal nanorods were dominated at (0002) direction with a lattice constant of
∼5.03 Å. The optoelectronical properties were studied by PL emission spectroscopy. A strong UV emission at 380 nm was observed. The band gap of the single ZnO nanorod was directly measured to be 3.36 eV using a conductive AFM. The superiority of patterned ZnO nanorods indicates their
great potential in field emission display arrays.
A Study of Nanomaterial Dispersion in Solution by Wet-Cell Transmission Electron Microscopy
Authors: Franks Ryan , Morefield Sean , Wen Jianguo , Liao Dongxiang , Alvarado Jorge , Strano Michael , Marsh Charles
Published: April 2020

Preparation of nanomaterial dispersion or nanofluids requires good characterization techniques, including particle size and morphological measurements. A reliable and straight-forward process to characterize and quantify the degree of dispersion and agglomeration is needed. A wet-cell
transmission electron microscope (TEM) technique has been developed to make comparisons between sonicated and hand-shaken solutions of both aluminum oxide nanoparticles and multi-walled carbon nanotubes. In each case, the wet-cell TEM technique reveals images of nanoparticles well dispersed
in aqueous solutions due in part to the use of ultrasonic power instead of simply manual shaking and stirring. The technique is currently qualitative and shows great potential for a host of nanotechnology applications.
Novel Nanohybrids Derived from the Attachment of FePt Nanoparticles on Carbon Nanotubes
Authors: Tsoufis Theodoros , Tomou Aphrodite , Gournis Dimitrios , Douvalis Alexios P. , Panagiotopoulos Ioannis , Kooi Bart , Georgakilas Vasilios , Arfaoui Imad , Bakas Thomas
Published: April 2020

Multiwalled carbon nanotubes (MWCNTs) were used as nanotemplates for the dispersion and stabilization of FePt nanoparticles (NPs). Pre-formed capped FePt NPs were connected to the MWCNTs external surface via covalent binding through organic linkers. Free FePt NPs and MWCNTs-FePt hybrids
were annealed in vacuum at 700 °C in order to achieve the L10 ordering of the FePt phase. Both as prepared and annealed samples were characterized and studied using a combination of experimental techniques, such as Raman and Mössbauer spectroscopies, powder X-ray Diffraction
(XRD), magnetization and transmittion electron microscopy (TEM) measurements. TEM measurements of the hybrid sample before annealing show that a fine dispersion of NPs along the MWCNTs surface is achieved, while a certain amount of free particles attached to each other in well connected dense
assemblies of periodical or non-periodical particle arrangements is also observed. XRD measurements reveal that the FePt phase has the face-centered cubic (fcc) disordered crystal structure in the as prepared samples, which is transformed to the face-centered tetragonal (fct) L10
ordered crystal structure after annealing. An increase in the average particle size is observed after annealing, which is higher for the free NPs sample. Superparamagnetic phenomena due to the small FePt particle size are observed in the Mössbauer spectra of the as prepared samples. Mössbauer
and magnetization measurements of the MWCNTs-FePt hybrids sample reveal that the part of the FePt particles attached to the MWCNTs surface shows superparamagnetic phenomena at RT even after the annealing process. The hard magnetic L10 phase characteristics are evident in the magnetization
measurements of both samples after annealing, with the coercivity of the hybrid sample over-scaling that of the free NPs sample by a factor of 1.25.
Fullerene C60–Silver Nanoparticles Hybrid Structures: Optical and Photoelectric Characterization
Authors: Dmitruk N. L. , Borkovskaya O. Yu. , Mamykin S. V. , Naumenko D. O. , Berezovska N. I. , Dmitruk I. M. , Meza-Laguna V. , Alvarez-Zauco E. , Basiuk E. V.
Published: April 2020

A detailed optical and photoelectric characterization of pristine fullerene C60 films deposited onto n-silicon substrates (C60/Si), C60 films crosslinked by means of the solvent-free chemical functionalization with 1,8-diaminooctane (C60-DA/Si),
and the pristine and crosslinked films decorated with silver nanoparticles (C60-Ag/Si and C60-DA-Ag/Si), was carried out. The reflectance spectra obtained allowed to calculate the absorption coefficient (α = 4pik/λ) spectral dependencies
and the spectra of light transmittance in layered barrier structures metal(Au)/fullerene/Si. Photoelectric properties of the films were investigated as well. The experimentally measured values of band gap were in a good agreement with mobility gap values (2.3±0.1 eV). The decoration
of fullerene films (both pristine and chemically crosslinked) with silver nanoparticles did not change the photocurrent spectra as compared to those for undecorated fullerene films, but lowered the values of internal quantum efficiency Qint. The photocurrent generated in
fullerene/Si heterostructure, showed a maximum value at λ ∼450 nm (Qint max≈0.25 for decorated and undecorated C60-DA/Si films), and it was higher for the samples based on pristine C60 films, in accordance with their higher absorption
coefficient. Diminishing of Qint for C60-DA/Si and C60-DA-Ag/Si films was observed for the spectral range of photocurrent generated in Si layer. The analysis of dark current–voltage characteristics showed that the barrier properties differ insignificantly,
though a certain increase of series resistance was observed for the C60-DA/Si samples.
Polyaniline Nanorods and Hollow-Microspheres Prepared by Using Copper Wires or Rings as Template
Authors: Gao Yu , Wang Fengchun , Gong Jian , Su Zhongmin , Qu Lunyu
Published: April 2020

Polyaniline nanorods and hollow-microspheres have been successfully prepared by using copper wires and rings, respectively, as template in the presence of H4SiW12O40 and ammonium persulfate, which used as dopant and oxidant, respectively in this system.
Different morphology of the resulting products can be obtained and controlled by using corresponding different shape of the objects. Furthermore, the template of this method not only needn't contain or react with chemicals but also the removal of it is extremely easy and facile without solvent
or extra disposal. Meanwhile, possible formation processes of polyaniline nanorods and hollow-microspheres are proposed. The structure and morphology of the polyaniline nanorods and hollow-microspheres were characterized by Fourier Transform Infrared Spectrophotometer spectra, X-ray diffraction
patterns, Scanning Electron Microscope images, and Transmission Electron Microscopy images. Prompted by the high surface areas, small diameter, and porous structure of the prepared polyaniline, we constructed the polyaniline gas sensors and found that the polyaniline hollow-microspheres had
better sensitivity than the polyaniline nanorods to NH3 gas.
Ammonia Adsorption on Nanostructured Silica Materials for Hydrogen Storage and Other Applications
Authors: Roque-Malherbe R. , Marquez-Linares F. , Del Valle W. , Thommes M.
Published: April 2020

Our focus in the present study is to apply high specific surface area silica nanostructured porous materials (about 2,200 m2/g, as synthesized, and 600–700 m2/g, after stabilization) to adsorb ammonia (NH3) for hydrogen storage and other chemical
and pollution abatement applications. We describe here the synthesis, and characterization of these silica materials, and the adsorption study of N2 and NH3. These materials were obtained with the help of a modification of the Stöber-Fink-Bohn (SFB) method. The main
change, made here to the SFB method, was the use of amines, i.e., triethylamine as catalysts instead of ammonium hydroxide. The silica materials have been characterized with the help of SEM and FTIR Spectrometry. The N2 adsorption study was carried out with the help of the Quantachrome-Autosorb-1
and the NH3 adsorption with the Quantachrome-Autosorb-1-C. The amount of hydrogen adsorbed in the form of NH3 in the studied silica samples at: P = 760 [Torr] (1.01325×105 [Pa]), was 2 [wt.%] and the amount of hydrogen stored in the form
of NH3 at about: P = 7500 [Torr] (10.0×105 [Pa]), in the studied stabilized silica samples was 11 wt.%, a magnitude higher than the goal figure of 6.5 [wt.%] established by the United States of America, Department of Energy.
Polymer Solar Cells with Ternary Blend Nanolayers
Authors: Kim Youngkyoo , Shin Minjung , Kim Hwajeong
Published: April 2020

We report polymer solar cells with a polymer blend nanolayer (film) that consists of two electron-donating polymers and one electron-accepting polymer. Regioregular poly(3-hexylthiophene) (P3HT) and poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) were employed
as electron-donating polymers, whilst poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) was used as an electron-accepting polymer. Two kinds of solvent and film thickness were applied to examine their effect on the device characteristics. Results showed that the device performance was better
when p-xylene was used as a solvent, whilst thicker blend films exhibited better power conversion efficiency. A nanohole morphology found in the blend film made using chlorobenzene, compared to the blend film made using p-xylene, was assumed to be responsible for the relatively
poor device performance in spite of higher absorption in the longer wavelengths. Still low efficiency of present devices was attributed to the existence of charge blocking resistances in the bulk polymer nanolayer.
Quench-Ring Assisted Flame Synthesis of SiO2-TiO2 Nanostructured Composite
Authors: Worathanakul Patcharin , Jiang Jingkun , Biswas Pratim , Kongkachuichay Paisan
Published: April 2020

A flame aerosol reactor (FLAR) was used to synthesize SiO2-based nanocomposite materials of SiO2-TiO2 in different precursor molar ratios and quench ring positions. Processing conditions were determined that resulted in formation of different crystal
phases at different precursor concentration molar ratios. The results showed that the addition of SiO2 inhibited TiO2 phase transformation from anatase to rutile. The different morphology of SiO2-TiO2 nanocomposite was primarily the result of changing
the quench ring position. Quenching can stop the growth kinetics, and this was obtained by locating the quench ring at different positions in the particle formation process. At a lower position, a binary mixture of SiO2-TiO2 was obtained in a core–shell structure.
The difference in residence time for sintering and coalescence yielded different morphologies of SiO2-TiO2 nanocomposites. The results from FTIR confirmed Si-O-Ti bonding for all samples. The samples of SiO2-TiO2 exhibited better suspension in liquid
than pure TiO2 as confirmed by zeta potential measurements.
Stability of Hydrophilic Magnetic Nanoparticles Under Biologically Relevant Conditions
Authors: Chen Z. P. , Zhang Y. , Xu K. , Xu R. Z. , Liu J. W. , Gu N.
Published: April 2020

Hydrophilic 2,3-dimercaptosuccinnic acid (HOOC-CH(SH)-CH(SH)-COOH, DMSA) coated monodisperse magnetic nanoparticles (Fe3O4 were dispersed in water, RPMI-1640 with 10% (v/v) fetal calf serum, RPMI-1640, PBS and MES, respectively, to investigate their stability under
biologically relevant conditions. The Photon Correlation Spectroscopy (PCS) results showed that DMSA-Fe3O4nanoparticles existed as aggregate under biological conditions. UV-vis, MRI and AFM results indicated that DMSA-Fe3O4 nanoparticles dispersed
in RPMI-1640, PBS and MES presented poor stability, whereas those dispersed in RPMI-1640 with fetal calf serum exhibited excellent stability, which was due to their adsorption from fetal calf serum, as confirmed by zeta potential and IR results. Additionally, in vitro cell experiments
showed that DMSA-Fe3O4 nanoparticles with adsorption from fetal calf serum had higher intracellular uptake than those without adsorption from serum, indicating that fetal calf serum could play a great role in intracellular uptake of nanoparticles.
Incorporation of Gold Nanoparticles Within Thermoresponsive Microgel Particles: Effect of Crosslinking Density
Authors: Dong Yang , Ma Ying , Zhai Tianyou , Zeng Yi , Fu Hongbing , Yao Jiannian
Published: April 2020

Hybrid microgel particles were prepared by one step incubation of poly(N-isopropylacrylamide)-co-poly(acrylic acid) (PNIPAM-co-PAA) and gold nanoparticles (AuNPs). PNIPAM-co-PAA microgel particles were synthesized by surfactant-free emulsion polymerization
with different crosslinking densities (4.5 wt.-%, 10 wt.-%, 15 wt.-%, MBA to NIPAM) and AuNPs obtained by trisodium citrate reduction method independently. The effect of crosslinking density of synthesized microgel particles on the loadings of AuNPs was investigated. The results showed that
18±2 nm AuNPs could be well entrapped in the loosely crosslinked (4.5 wt.-%, MBA to NIPAM) PNIPAM-co-PAA microgel particles with high loadings. The final hybrid microgel particles were well characterized by transmission electron microscopy (TEM), UV-vis spectra, X-ray photoelectron
spectroscopy (XPS), X-ray diffraction (XRD) and FT-IR. In particular, the PNIPAM-co-PAA/AuNPs hybrid microgel particles were thermoresponsive and completely reversible with several heating/cooling cycles. Therefore, the PNIPAM-co-PAA/AuNPs hybrid microgel particles allow for
combined surface plasmon and thermal switching applications.
Transmission Electron Microscopy of ZnO Nanotube Arrays Etched from Electrodeposited ZnO Nanorods
Authors: Su Jun , Che Renchao , She Guangwei , Duan Xiaofeng , Shi Wensheng
Published: April 2020

Well aligned large-scale ZnO nanorods were produced by a simple eletrodeposited process. Then, ZnO nanotubes arrays were formed via a subsequent etching in alkaline solution. Extensive studies including SEM, TEM, EDX, STEM and EELS indicate that the Zn and O elemental composition of
the nanorods was well-proportioned along the whole cross section and the ZnO nanotubes were Zn terminated at (0001) polar surface toward the growth direction.
One-Pot Assembly of Cu2O Chain-Like Hollow Structures
Authors: Zhang Hua , Zhang Dongfeng , Guo Lin , Zhang Rui , Yin Penggang , Wang Rongming
Published: April 2020

Novel Cu2O chain-like network was assembled via a facile one-pot solution process with the assistance of poly(vinylpyrrolidone) (PVP). TEM observations showed that the chain-like structures were aggregated by hollow spheres ∼70 nm in diameter. To be worth mentioning,
HRTEM image recorded from the coherent interfacial region demonstrated that the lattice fringes penetrate from one sphere into the adjacent one smoothly without apparent diffraction contrast, which indicated that the hollow spheres experienced lattice fusion and grew into each other. Based
on the systematic studies, an oriented aggregation mechanism was proposed, i.e., Cu2O nanoparticles into hollow spheres and subsequently the hollow spheres into the chain-like structures. The Raman spectra of the Cu2O chain-like hollow nanostructures were also investigated.
It was found that the Raman peak intensity is different from that in the previous reports, which might be originated from the structure defect resulted from the oriented attachment.
Hierarchical ZnO Nanostructures: Growth and Optical Properties
Authors: Umar Ahmad , Hajry A. Al. , Al-Heniti S. , Hahn Y.-B.
Published: April 2020

Growth of hierarchical ZnO nanostructures composed of ZnO nanoneedles have been achieved via simple thermal evaporation process by using metallic zinc powder in the presence of oxygen at low temperature of 460 °C on silicon substrate without the use of any kind of metal catalysts
or additives. It is confirmed by detailed structural studies that the as-grown hierarchical nanostructures are single crystalline with a wurtzite hexagonal phase and nanoneedles of these structures are grown along the c-axis in the [0001] direction. The Raman-scattering analysis substantiates
a wurtzite hexagonal phase with a good crystal quality for the as-grown products. Room-temperature photoluminescence (PL) exhibits a strong UV emission at 380 nm confirming the excellent optical properties of as-synthesized hierarchical structures. A plausible growth mechanism is also proposed
to clearly understand the growth process of the synthesized structures.
Theoretical Study of Vanadium Oxides Interaction with Y-Zeolite
Authors: Arroyo M. , Sansores L. E. , Salcedo R. , Montoya J. A.
Published: April 2020

A current problem about oils and feedstock in fluid catalytic cracking (FCC) is the continuous cumulative deposition of metal contaminants on the catalyst, resulting in important modifications of its properties. Vanadium plays a detrimental role on the catalyst components because enhances
the destruction of the Y-zeolite structure during regeneration stage when it is exposed by steam and oxygen at high temperatures. Knowledge of the mechanism interaction of vanadium with the catalyst is important to improve FCC performance. Quantum Molecular Dynamics calculations were done
introducing the VO, V2O3, VO2 or V2O5 molecules at the center of a Y-zeolite ring simulating regeneration conditions. The results indicate that the principal reaction is carried out among the zeolite and the vanadium atoms of molecules.
This happens, when interaction is presented, since the loss of a hydrogen atom of the active place causes high degree of oxygen reactivity.
Thermoluminescence Properties of Undoped and Dy3+ Doped ZrO2 Nanophosphor Under β-Ray Irradiation
Authors: Rodríguez R. A. , De la Rosa E. , Romero V. H. , Meléndrez R. , Salas P. , Diaz-Torres L. A. , Barboza-Flores M.
Published: April 2020

The thermoluminescence (TL) of undoped and Dy3+ doped ZrO2 nanocrystals under β-ray irradiation is reported. The TL glow curves are the result of the overlapping of four TL peaks produced partly by the intrinsic defect of highly asymmetrical monoclinic
structure and partly due to defects produced during the synthesis process. The introduction of dopant ions induces changes in the glow curve due to the enhancement of high temperature peaks intensity. The results show that both undoped and doped ZrO2 nanocrystalline phosphor present
good TL efficiency as well as good dose response which qualify them as a potential β-ray dosimeter.
Synthesis and Characterization of Porous Mo-W Oxide Nanostructures
Authors: Paraguay-Delgado F. , Verde Y. , Cizniega E. , Lumbreras J. A. , Alonso-Nuñez G.
Published: April 2020

The present study reports the synthesis method, microstructure characterization, and thermal stability of nanostructured porous mixed oxide (MoO3-WO3) at 550 and 900 °C of annealing. The material was synthesized using a hydrothermal method. The precursor was
prepared by aqueous solution using ammonium heptamolibdate and ammonium metatungstate, with an atomic ratio of Mo/W = 1. The pH was adjusted to 5, and then the solution was transferred to a teflon-lined stainless steel autoclave and heated at 200 °C for 48 h. The resultant material was
washed using deionized water. The specific surface area, morphology, composition, and microstructure before and after annealing were studied by N2 physisorption, scanning electron microscopy (SEM), analytical transmission electron microscopy (TEM), and X-Ray diffraction (XRD). The
initial synthesized materials showed low crystallinity and high specific surface area around (141 m2/g). After thermal annealing the material showed higher crystallinity and diminished its specific surface area drastically.
Nanostructured Cd1−xMnxS Films for Spintronics and Optoelectronic Device Applications: Synthesis and Characterization
Authors: Reddy D. Sreekantha , Reddy B. K. , Gunasekhar K. R. , Reddy P. Sreedhara
Published: April 2020

Nanostructured Cd1−xMnxS (x = 0.3 and 0.4) films were prepared on glass substrates by thermal evaporation. All the films were deposited at 373 K and annealed at 473 K in high vacuum of 2 × 10−6 mbar. The nanostructure
films were characterized for composition, structure, morphology, optical and magnetic properties. All the films exhibited wurtzite structure of the host CdS material. AFM studies showed that all the films were in nanocrystalline form with the grain size varying in the range of 25–43
nm. The magnetic susceptibility increased sharply with Mn content 'x'.
Photoinduced Birefringence in Nanostructured SiO2:DR1 Sol–Gel Films
Authors: Franco Alfredo , García-Macedo Jorge A. , Marino I. G. , Lottici P. P.
Published: April 2020

Pump-probe photoinduced birefringence measurements were carried out in amorphous and in nanostructured sol–gel films with Disperse Red 1 (DR1) azochromophores embedded in a SiO2 matrix. X-ray diffraction (XRD) patterns determine the long-range nanostructure order of
the films, exhibiting a lamellar nanostructure, with two different d-spacings, due to the presence during the sol–gel process of the Sodium Dodecyl Sulfate (SDS) or of the Cetyltrimethylammonium Bromide (CTAB) ionic surfactants. The photoinduced birefringence measurements were
performed on fresh and on heat treated films as a function of the pumping time. The measurements give us information about the effect of the nanostructures on the azochromophores orientation dynamics. As a result, for the same azochromophores concentration, annealed nanostructured films exhibited
the largest azochromophore mobilities but by the other side, amorphous films had the largest signal intensities. Besides, we established a phenomenological model for the analysis of the azochromophores orientation in the films as a function of the pumping time.
Exciton Polaritons in One-Dimensional Metal-Semiconductor Photonic Crystals
Authors: Márquez-Islas R. , Flores-Desirena B. , Pérez-Rodríguez F.
Published: April 2020

We investigate theoretically the coupling of exciton with light in a one-dimensional photonic crystal. The unit cell of the crystal consists of two alternating layers, namely a metallic layer and a semiconductor one. The frequency-dependent dielectric function of the metal is described
by the Drude model, whereas for the semiconductor we use a nonlocal excitonic dielectric function. The polariton dispersion for s-polarized modes in the metal-semiconductor photonic crystal is compared with that for a dielectric-semiconductor photonic crystal. Because of the metal layers,
a low-frequency gap appears in the photonic band structure. The presence of the semiconductor gives rise to photonic bands associated with the coupling of light with size-quantized excitón states. At frequencies above the longitudinal exciton frequency, the photonic band structure exhibits
anticrossing phenomena produced by the upper exciton–polariton mode and size-quantized excitons. It is found that the anticrossing phenomena in the metal-semiconductor photonic crystal occur at higher frequencies in comparison with the dielectric-semiconductor case.
Magnetic Properties of a Pair of V4 Interacting Clusters in a Fe Matrix
Authors: Montejano-Carrizales J. M. , Alvarado-Leyva P. G. , Sosa-Hernandez E. M.
Published: April 2020

The magnetic properties of a pair V4 atomic clusters embedded in bulk Fe are determined by using a realistic spd-band Hubbard-like model. The spin density distribution is calculated self-consistenly in the unrestricted Hartree-Fock approximation. The local magnetic
moments μ(i) are obtained at various atoms i of the cluster and of the surrounding Fe matrix. We consider two different geometrical arrangements for V clusters, collinear (C) and non-collinear (NC). In all the cases studied the magnetic coupling in the interface cluster-matrix
is antiferromagnetic, and the ferromagnetic order of the matrix is not broken by the presence of the V atoms, although the local magnetic moments of Fe atoms at the interface cluster-matrix, are reduced respect to Fe bulk magnetization (2.22 μB) about 8%–20%. We
compare the results with those of just one V4 atomic cluster embedded in bulk Fe.
Studies of Point Defect Formation and Self-Compensation in Indium Doped ZnO Nanorods by STM and STS
Authors: González-Carrazco A. , Herrera-Zaldívar M. , Pal U.
Published: April 2020

The effect of indium doping on the point defect formation in ZnO nanostructures is studied by scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) techniques. While the incorporation of a donor dopant like indium should increase the n-type conductivity
of ZnO nanostructures, it has been found that formation of VZn native acceptors in heavily doped ZnO nanostructures produces self-compensation effect, creating acceptor states in their band gap. Presence of both donor and acceptor states in heavily indium doped ZnO nanostructures
are probed and identified. The mechanism of formation of such donor and acceptor states is discussed.
Thermal Phase Stability and Catalytic Properties of Nanostructured TiO2-MgO Sol–Gel Mixed Oxides
Authors: Lopez T. , Hernandez-Ventura J. , Aguilar D. H. , Quintana P.
Published: April 2020

Several compositions in the system TiO2-MgO were prepared via sol–gel method. The structural evolution of the samples was followed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermal analysis (DTA/TG). In order to study the crystalline
phase stability over time, the amorphous fresh gels were subjected to successive thermal treatments from 100 to 1100 °C, with a total annealing time of 442 h. Below 350 °C, magnesium acetates and oxalates phases were detected; at higher temperatures the binary compounds MgTi2O5,
MgTiO3 and Mg2TiO4 appeared over a wide range of compositions. In the titania rich end, brookite, anatase and rutile were detected, these phases easily reacted to form the binary oxides; in contrast, on the rich-end magnesia, periclase showed an overall high
stability. The successive thermal treatments over an extended period of time allowed a better control of nanosized crystallite growth; for anatase was 30 nm, below 850 °C, and for rutile was 45 nm, between 600 °C and 1000 °C. Magnesia showed a constant value of 22 nm on the overall
studied temperatures. The best catalytic performance for 2-propanol decomposition was achieved by 90Ti/10Mg, annealed at 400 °C; this indicates that when magnesium is added to titania, the catalytic activity improves due to the introduction of structural defects and charge deficiencies.
For 2-butanol decomposition, the formation of cis and trans isomers indicates the presence of high acidity sites.
Machines, Monsters, and Coffin Corners: Broadcast Meteorologists’ Use of Figurative and Intense Language during Hurricane Harvey
Authors: Prestley Robert , Olson Michele K. , Vos Sarah C. , Sutton Jeannette
Published: April 2020

During impactful weather events, television broadcast meteorologists act as high-profile risk communicators by interpreting complex weather information for viewers. However, the specific language choices broadcast meteorologists make in these situations have rarely been studied. This qualitative study investigates how meteorologists used figurative and emotionally intense language to interpret threats and impacts during Hurricane Harvey in August 2017, using 24 h of live broadcasts from KHOU, a Houston CBS affiliate. The results of this inductive, thematic analysis suggest that KHOU meteorologists framed Harvey as an all-encompassing monster and as a heat-seeking machine. The meteorologists also relied on emotionally intense language to emphasize Harvey’s extreme threat and to express their concern and disbelief about Harvey’s impact. This study indicates the specific and multifaceted ways broadcast meteorologists communicate risk and science during high-impact events and identifies key questions for future research.
Subannual to Interannual Variabilities of SST in the North Atlantic Ocean
Authors: Li Xiaofan , Hu Zeng-Zhen , Huang Bohua
Published: April 2020

Based on observational data, this work examines the multi-time-scale feature of the sea surface temperature (SST) variability averaged in the whole North Atlantic Ocean (to be referred to as NASST), as well as its time-scale-dependent connections with El Niño–Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO). Traditionally, the NASST index is used to characterize the SST trend and multidecadal variability in the North Atlantic. This study found that superimposed on a prominent long-term trend, NASST is nonnegligible at subannual and interannual time scales, compared with that at decadal to multidecadal time scales. Spatially, the interannual variation of NASST is characterized by a horseshoe-like pattern of the SST anomaly (SSTA) in the North Atlantic. It is mainly a lagged response to ENSO through the atmospheric bridge, and NAO plays a secondary role. At the subannual time scale, both ENSO and NAO play a role in generating the fluctuations of NASST and a horseshoe-like pattern in the North Atlantic. Nevertheless, both the ENSO- and NAO-driven variations only explain a small fraction of the variances in both the interannual and subannual time scales. Thus, other factors unrelated to ENSO or NAO may play a more important role. The associated thermodynamical processes are similar at the two time scales; however, the dynamical processes have a significant contribution to the subannual component, but not to the interannual component. Thus, the SSTA averaged in the North Atlantic as a whole varies at different time scales and is associated with different mechanisms.
Simulated Impact of the Tibetan Glacier Expansion on the Eurasian Climate and Glacial Surface Mass Balance during the Last Glacial Maximum
Authors: Liu Yonggang , Wu Yubin , Lin Zhongda , Zhang Yang , Zhu Jiang , Yi Chaolu
Published: April 2020

Glaciers over the Tibetan Plateau and surrounding regions during the Last Glacial Maximum (LGM) were much more extensive than during the preindustrial period (PI). The climate impact of such glacial expansion is studied here using the Community Atmosphere Model, version 4 (CAM4). To cover the range of uncertainty in glacier area during the LGM, the following three values are tested: 0.35 × 106, 0.53 × 106, and 0.70 × 106 km2. The added glacier is distributed approximately equally over the Pamir region and the Himalayas. If 0.70 × 106 km2 is used, the annual mean surface temperature of the glaciated regions would be cooled by ~3.5°C. The annual mean precipitation would be reduced by 0.2 mm day−1 (10%) and 2.5 mm day−1 (24%) over the Pamir region and Himalayas, respectively. The surface mass balance (SMB) of the glaciers changes by 0.55 m yr−1 (280%) and −0.32 m yr−1 (−20%) over the two regions, respectively. The changes in SMB remain large (0.29 and −0.13 m yr−1), even if the area of the Tibetan glacier were 0.35 × 106 km2. Therefore, based on the results of this particular model, the expansion of glaciers can either enhance or slow the glacial growth. Moreover, the expansion of glaciers over the Himalayas reduces summer precipitation in central and northern China by ~0.5 mm day−1 and increases summer precipitation in southern Asia by ~0.6 mm day−1. The expansion of glaciers over the Pamir region has a negligible influence on the precipitation in these monsoonal regions, which is likely due to its large distance from the main monsoonal regions.
Beyond Climate Impacts: Knowledge Gaps and Process-Based Reflection on Preparing a Regional Chapter for the Fourth National Climate Assessment
Authors: Roesch-McNally Gabrielle , Chang Michael , Dalton Meghan , Lowe Scott , Luce Charlie , May Christine , Morishima Gary , Mote Philip , Petersen Alexander “Sascha” , York Emily
Published: April 2020

The Fourth National Climate Assessment (NCA4) provided the most up-to-date understanding of climate change and its effects on the Earth system and on consequences for the United States, including impacts and associated risks, along with approaches to coping with these effects. It is intended to provide guidance to decision-makers in governmental sectors while, in practice, providing guidance for nongovernmental actors. Its regional and topical chapters highlight current knowledge, uncertainties, gaps in knowledge, and emerging threats. The current knowledge and gaps can help set a research agenda to inform future national, regional, and local climate assessments and thereby support better decision-making. The evolution of the assessment, including greater diversity in participation, and more grounded research in the Northwest represents a growing and deepening engagement with more diverse participants. This shift emphasizes the importance of diversity, inclusion, and a greater acknowledgment of multiple ways of knowing, including local and Indigenous knowledge. The Northwest chapter reflects the broader shift in framing from NCA3 to NCA4 to better understand how climate impacts pose risks to things of value in each sector or region. It considers climate impacts through five broad ways in which humans relate to the environment: natural resource economy; heritage and quality of life; water, transportation, and infrastructure; health and social systems; and frontline communities. We reflect on the assessment process and identify three recommendations to improve the assessment outcomes and processes: seek new ways to 1) engage diverse authors and stakeholders and 2) value and integrate epistemic plurality and different knowledge systems, and 3) when gaps are identified, promote research or data collection efforts designed to fill those gaps. Done well, the assessment can build support and knowledge to facilitate community action, leading to broader resilience.
The Ghetto President and Presidential Challenger in Uganda
Authors: Osiebe Garhe
Published: April 2020

The political history of post-colonial Uganda is about as fascinating as that of any post-colonial state. The styles of key political figures, including Milton Obote and Idi Amin Dada, who have had the privilege of leading the country, are central to this fascination. Yet, since becoming Uganda’s leader in 1986, President Yoweri Museveni appears to have outdone his predecessors so much so that an entire generation cares little of the country’s history before Museveni. In 2021, the Ugandan people are scheduled to go to the polls in a presidential election. Following the success of a bill in parliament to expunge an upper age limit to contest for the office of president, the seventy-five -year-old Museveni is set to seek an additional mandate. Unlike in his previous electoral contests, however, Museveni faces the challenge of a man less than half his age. Thirty-seven year-old Robert Kyagulanyi is among the most successful popular musicians in East Africa. Kyagulanyi has since exploited his success and fame to become an elected Member of Uganda’s Parliament. Barely two years after the artist materialised as a politician, the Ghetto President, as he is popularly known, has declared his intention to run for the office Museveni occupies, against Museveni. Since Museveni permitted electoral contests for the presidency of Uganda, he has remained defiantly invincible. How does Kyagulanyi propose to undo this, and why does he think he can, to the extent of daring? Drawing on a socio-biographical analysis of the celebrity MP, some strategic interviewing and student-participant observation, the article engages the dynamics inherent with some of these issues.
Nicorandil for Periprocedural Myocardial Injury in Elective Percutaneous Coronary Intervention: A Meta-Analysis of 10 Randomized Controlled Trials
Authors: Yi Bin , Luo Jinwen , Jiang Yumei , Mo Shaoyan , Xiao Xiaoyi , Chen Xiang , Rong Jian
Published: April 2020

The clinical outcomes of nicorandil in percutaneous coronary intervention (PCI) are conflicting. We sought to evaluate the effects of nicorandil on periprocedural myocardial injury (PMI) in elective PCI. Eligible studies that reported the effect of nicorandil on PMI in elective PCI were obtained from PubMed, Web of Science, and Cochrane Library (up to October 28, 2019). The outcomes were PMI and major adverse cardiovascular and cerebrovascular events (MACCEs). Ten randomized controlled trials with 1304 patients undergoing elective PCI were evaluated. Nicorandil significantly reduced the incidence of PMI (odds ratio [OR] = 0.48; P = .0003); however, there was no significant difference in MACCEs (OR = 0.80; P = .45) between the 2 groups. Subgroup analyses showed that nicorandil significantly lowered the PMI risk when only patients with stable coronary artery disease (OR = 0.41; P = .0008) were considered and when nicorandil was administered intravenously (OR = 0.41; P = .0007) or orally (OR = 0.33; P = .0001). This meta-analysis suggests that nicorandil could reduce the incidence of PMI without increasing the occurrence of MACCEs in elective PCI. The effect of nicorandil in lowering the PMI risk is associated with the diagnosis of the patients and the route of nicorandil administration.
Does trust in supervisors translate to compliance and cooperation? A test of internal procedural justice among Taiwanese police officers
Authors: Wang Shun-Yung Kevin , Sun Ivan Y , Wu Yuning , Van Craen Maarten , Kuen-Lung Hsu Kevin
Published: April 2020

The procedural justice model of policing has gained much popularity in scholarship and empirical support in democracies, yet research on the procedural justice within police organizations, particularly the mediating mechanisms connecting internal procedural justice and officer behavioral tendencies, is rather limited. With an aid of survey data collected from Taiwanese police officers, this study tests the connections between internal procedural justice and officers’ compliance with agency rules and cooperation with supervisors via an essential element—trust in supervisors. Internal procedural justice was found to be directly related to trust in supervisors and officer cooperation with supervisor, whereas the association between internal procedural justice and compliance with agency rules is mainly indirect through trust in supervisors. This study concludes with discussing research and pragmatic implications of findings.
« Missa dos Quilombos » : La messe transformée en spectacle de dénonciation ou quand le rituel, l’art et l’éthique se rencontrent
Authors: Cardita Ângelo
Published: April 2020

Le 22 novembre 1981, à Recife, Brésil, une messe a été célébrée dans le but de conduire l’Église catholique brésilienne à s’intéresser à la question des noirs. L’encadrement rituel de la « Missa dos Quilombos » est resté celui d’une messe catholique, mais son déroulement a suivi une dynamique toute particulière, laquelle a suscité de multiples reprises de cette messe devenue événement, marchandise, spectacle, et aussi ressource pédagogique. Ainsi, la « Missa dos Quilombos » doit se comprendre du point de vue de la fragmentation rituelle en lien avec la vitesse du temps post-moderne, qui, selon Victor Turner, est à l’origine des phénomènes « liminoïdes ». Dans cette foulée, on se concentre ici sur les différents aspects d’une telle fragmentation rituelle que la « Missa dos Quilombos » permet d’illustrer. On sera ainsi en mesure de voir non seulement des essais de rencontre entre le rite, l’art et l’éthique, mais aussi leur éloignement du berceau religieux.
Éclectisme et polysémie des « théories du complot » sur le Web et dans l’industrie du divertissement. Enquête ethnographique sur leur réception par des élèves (15–18 ans) suisses et français
Authors: Rouiller Sybille
Published: April 2020

En France, suite aux attentats de Paris en 2015, plusieurs enquêtes d’opinions et articles de presse (Kreis, 2015) établissent des liens importants entre « numérique », « théories du complot », « crédulité » et « radicalisation » qui toucheraient en particulier la jeunesse actuelle. A partir d’une enquête ethnographique dans des établissements scolaires secondaires en France et en Suisse, cet article propose d’apporter un éclairage sur la diversité des représentations et usages des « théories du complot » chez des adolescents (15–18 ans). Il abordera notamment l’éclectisme et la polysémie des « théories du complot » en circulation sur le Web et dans l’industrie du divertissement. Enfin, il prêtera une attention particulière aux comportements que ces adolescents adoptent face au jugement que leurs pairs ou les enseignants – voire la chercheuse – pourraient porter sur ces thématiques dans un contexte où ces dernières sont souvent réduites à un mode de pensée irrationnel ou un signe d’embrigadement politique ou religieux.